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Environmental Scoping Study of Snettisham-Ketchikan Transmission Line System 1 of 2 1981
7 RECEIVER Noy 36 198} ENVIRONMENTAL SCOPING” STUDY OF | SNETTISHAM/KETGHIKAN TRANSMISSION LINE SYSTEM NOVEMBER 1981 /WWHSILLINS 40 aanis ONIdODS VWINIWNOIANG PREPARED FOR U.S. DEPARTMENT OF ENERGY ALASKA POWER ADMINISTRATION Under Contract No. A- 81-128 LIERARY COPY PROPERTY OF: Alaska Power Authority 334 W. 5th Ave. Anchorage, Alaska 99501 186l ¥3aGWIAON This report was tates Governme} Department of Ej express or imp] the accuracy, Ct product, or pro infringe privat commercial prodf manufacturer, 0 endorsement, reé¢ or any agency tf herein do not n Government or af JUN-T 002 DATE ISSUED TO a - 1 fp ee HIGHSMITH = 42-225 PRINTED INU.S.A. ysored by the United jhe United States Jakes any warranty, or responsibility for formation, apparatus, ts use would not to any specific me, mark, nstitute or imply its ted States Government uthors expressed the United States AM. ENVIRONMENTAL SCOPING STUDY OF SNETTISHAM/KETCHIKAN TRANSMISSION LINE SYSTEM NOVEMBER 1981 PREPARED BY: ENVIRONAID JUNEAU, ALASKA FOR THE U.S. DEPARTMENT OF ENERGY ALASKA POWER ADMINISTRATION P.O.BOX 50 JUNEAU, ALASKA 99802 Under Contract No. A-81-128 Department Of Energy Alaska Power Administration P.O. Box 50 Juneau, Alaska 99802 November 6, 1981 FOREWORD: Alaska Power Administration, as part of its continuing program to facilitate conversion of the State's major electric power systems from their present dependency on oil and gas to renewable and other plentiful energy resources and to improve service reliability, initiated prelimi- nary interconnection feasibility studies in Southeast Alaska in 1980. Study findings indicate that interconnection between Snettisham and Ketchikan is technically feasible and initial Alaska Power Administration analysis shows economic feasibility in the late 1980's. In preparation for further feasibility studies of the interconnection an environmental scoping study was prepared under contract for Alaska Power Administration. Purpose of the study was to determine the scope of environmental elements to be assessed in further feasibility studies. This report presents the findings of the scoping study. Environmental elements evaluated included electrical field effects on sea life, chlorine gas production from anode electrodes, corrosion effects on ships and shore facilities, magnetic field alteration, location of transmission line in relation to anchoring and fishing areas, and impacts of road construction and burial of the transmission line near shores. Study recommendations suggest further biological work where the transmission line will enter salt water and at sea electrode locations, study of corrosion hazards along shore areas near sea electrodes, location and evaluation of bottomfish and shellfish near proposed line locations, and studies of electro-magnetic effects on migratory behavior and migratory success of salmon. Sincerely, Je. Gare Robert J. Cross Administrator DANIEL M. BISHOP anonard 12175 Mendenhail Loop Road JUNEAU, ALASKA 9980 ] 907 789-9305 THE SCOPE OF ENVIRONMENTAL ELEMENTS RECOMMENDED FOR CONSIDERATION IN REGARD TO THE PROPOSED SNETTISHAM-KETCHIKAN D.C. POWER TRANSMISSION SYSTEM Prepared for: U.S. Department of Energy Alaska Power Administration Juneau, Alaska October 29, 1981 OBJECTIVES ... APPENDIX B: APPENDIX C: APPENDIX D: APPENDIX E: TABLE OF CONTENTS METHODS .....ccccccecs mse ceececcceas Sa felie\e,al sie) @) 1s Sisilicl'e ‘e46) 6: ilal «eile Colles fa Background Information .......ceececcccccccccrcccccccssscves Information Specific to Locale ...... pte lala! sla elie phsverai ey alle telelisito a Alaska Department of Fish & Game Biologists thet wieie) = eielerslisls National Marine Fisheries Service Biologists ........... Salmon Creek Hatchery Biologist ...............-- eo cewiceis Fishermen .....cccccccsecesese alfalts 6] 61 ela}: @1es6 te exe) sisi = wilelt liete U.S. Geological Survey .....-s.eecceees is nie losetet si eleteie else lets Municipalities ....ccccccccccsvees 41 oi at ol'61 ola volte te lalko! oi'p] 1 ellastoi'e fe of RESULTS | csi. c)4) 6 s\s 20 ese wie 910 sie teraleie 4 i araltehorda ialacss|51 51 Silas! t/a fale! (ol’e(al.s5 el olson (ele fa Effects of Electrical Fields Produced by Ground Current Electrodes on Sea Life .........eseeeeee Snettisham..... i fo 1s (wiets) 0] 1 «|S 01 60 (0 felnsal 6] 9) sls! eles le (oe ie lel «1 9180. 9\000 ere%e Petersburg ......... 9} &! 6] 6) 6: © 9 (0 (0 [6 Golo! 0141 0! 6) 6's [6 fe 9 lo (oie! 8) 9:19] © Sere nie ie! Wrangell ...cccccccccccccccccccvcccccccscsescssccces eis (er Ketchikan ....... fe {a16) 5] 31 61 sltel elle (a (e/isi ala} oo 0190 10 aCe le ol ob e) 6) 616 6 foe fare Chlorine Gas Production from Anode Electrodes ...........+.- Corrosion Effects on Ships and Shore Facilities ............ Snettisham .....ccccccccccscccccccessccsencscsccce Piel ehstens PETSLSDUTR 5 oie eis ss ioe; 0) 0) 01 5] 0) #110 0 10 10 61 918i sisi sis 9.0 oie we rele) 9 sie 6 61 ecerei Wrangell ......... ao} oY olfahe) wile) calke terie! a) 61 0} 9] 9-05) ol laie leaks (otlel etietielel ate (elelie ele Reteb tian | iota iste :s 6 6 iarste; 2215) «1 = [0\16\(0 00 ini ors) si sere sole we (ee lets) $j 6.0/0) ws ele leiet = Magnetic Field Alteration by Submarine D.C. Power Cable and Effects on Sea Life ...........---0-- Magnetic Field Alteration and Effects on Natigation by Magnetic Compass...... sie (0 {0 (0 (0! 0! vie! 9109 @ 10» is vie! ois Location of Submerged Cable and Effect on Anchoring or Fishing Areas .......ceccecccccscccesecces Construction Impacts ..... ccc ccccccccccccccsccssccssscsccee RECOMMENDATIONS ......ceeececcecees eis! 6 '/a)'s1'6 (els fore (otopsy eters yaaa fale Taltshl os APPENDIX A: Scope of Biological Effects for the Proposed D.C. Power Grid: Literature Review and Bibliography. Information Provided by ASEA Letter from Sigvard Smedsfelt re Swedish Tests on the Influence of Electric Current on Marine Fauna. Letter from Mr. S.L. Nilsson, re Location of HVDC Submarine Cable Systems; Nature, Scope of Effects. The Natural Magnetic Setting of the Proposed D.C. Transmission Route Page Ww WWWWWNNNHE WOW WANAAUL | 10 13 13 14 14 19 79 170 173 176 cro mA/cm2 msec mV/cm ohmcm ppt sec TRC TRO uA/cm2 V/cm LIST OF ABBREVIATIONS amperes amperes per meter degrees Celsius chlorine-induced oxidants centimeter direct current degrees Farenheit foot gauss hertz pound concentration lethal to 50% of test organisms meter milliampere per square centimeter milligram per liter millisecond millivolt per centimeter ohm-centimeter parts per thousand second total residual chlorine total residual oxidant species microampere per square centimeter volt volt per centimeter OBJECTIVES HHEHBRHHHEHEHEEEE This study was designed to identify environmental elements of the proposed power link which will require further, more detailed, consideration. Environmental elements evaluated in this study included: 1) 2) 3) 4) 5) 6) 7) Electrical field effects on sea life produced by ground current electrodes installed in salt waters. Populations evaluated include salmon (fry, fingerlings, adults), herring, capelin, halibut, black cod, crab, shrimp, and sea mammals. Chlorine gas production from anode electrodes. Corrosion effects on ships and shore facilities. Magnetic field alteration by the submarine DC power cable, and effects on sea life. Effects of magnetic field alteration on magnetic compass and navigation. Location of submerged cable in relation to anchoring or fishing areas. Impacts of road construction and trenching/burying of the DC line near shores. This work examines beneficial and adverse impacts which may be associated with the above elements and recommends the scope of future investigations which may be needed to deal with possible environmental concerns. METHODS The two basic types of information collected for this study are from: 1) Sources not directly related to the S.E. Alaska locale - library material, correspondence, phone conversations. wha 2) The location of the proposed power link, including the Alaska Department of Fish and Game in Juneau, Petersburg, Wrangell and Ketchikan, municipal governments, and fishermen in Petersburg, Wrangell and Ketchikan. Background Information Library computer researches were made at the University of Alaska, Fairbanks and at the Alaska State Library in Juneau. This work, completed by Ms. Jan Mills, is presented with a summary analysis in Appendix A. Personal contacts were made with the following people: Mr. Jon Dunlap - Electric Power Research Institute, Palo Alto, California. Dr. B. Kepshire - Principal Fish Culturist, Alaska Department of Fish and Game - FRED Division, Juneau, Alaska. Dr. Uno Lamm - Consultant to ASEA, Hillsborough, California. Mr. John McKinney - Duriron Company, Dayton, Ohio. Mr. Willis Osbakken - Chief, USGS Sitka Observatory, Sitka, Alaska. Mr. Jim Patchot’ - Manager, Transmission Design Section, Bonneville Power Administration, Portland, Oregon. Mr. Tom Pittman - U.S. Bureau of Mines, Douglas, Alaska. Dr. Thomas Quinn - College of Fisheries, University of Washington, Seattle, Washington. Mr. S. Smedsfelt - Chief Engineer, The Swedish State Power Board. Mr. Ken Williams - Norton Corrosion, Ltd., Woodinville, Washington. Dr. Bruce Wing - Biological Oceanographer, Auke Bay Laboratories, Auke Bay, Alaska. Mr. Greg Young - Fisheries Biologist, Salmon Creek Hatchery, Juneau, Alaska. Information Specific to Locale To obtain information specific to the transmission route locale, the following individuals were contacted. Alaska Department of Fish & Game Biologists Will Bergman - Area Biologist, Commercial Fish Division, Petersburg. Barry Bracken - Bottom Fish Biologist, Commercial Fish Division, Petersburg. =J= Al Dittier - Hatchery Manager, FRED Division, Snettisham. Tim Koeneman - Shellfish Biologist, Commercial Fish Division, Petersburg. Don Seidelman - Area Biologist, Sport Fish Division, Ketchikan. National Marine Fisheries Service Biologists H.R. Carlson - Auke Bay Biological Laboratories. Dr. Stan Rice - Auke Bay Biological Laboratories. Salmon Creek Hatchery Biologist Greg Young - (formerly at Snettisham Hatchery; also knowledgeable regarding electro fishing). Fishermen Mr. Dick Bishop, Ketchikan. Mr. Fred File, Petersburg. U.S. Geological Survey Mr. Willis Osbakken - Chief, Sitka Observatory. Municipalities Mr. Rick Braun - Planner, City of Petersburg. Ms. Joyce Rasler - City Manager, City of Wrangell. Visits were made to Snettisham and Petersburg for the purpose of interviewing and gathering information. Foul weather prevented intended visits to Wrangell and Ketchikan. Questions involving these areas were answered through phone conversations. 3B BPBRRRHEHREEREEEE & Results of this work are presented by the respective environmental elements. i Relevant conditions are described and possible beneficial or adverse impacts are discussed. Bases for evaluation of impacts are drawn from literature || review and analysis (Appendix A). Effects of Electrical Fields Produced by Ground Current Electrodes on Sea Life An important basis for evaluating electrical field effects is the strength of the electrical field as designed into the sea electrode system. The preliminary feasibility design, assuming seawater resistivity of 20 ohm-cn, predicts an electrical field as follows: Distance Voltage Current from Gradient penaay Electrode (cm) (mV/ cm) (mA /cm*) 0 40 20) 20 410 0.5 100 2.5 Be These calculated voltage gradients are generally too low to result in narcotizing or injuring fish. Voltage gradient at lam is less than 2% of the threshold level observed to attract a 20 cm trout in freshwater. Fish and other sea organisms will be able to sense the voltage gradients found at the electrodes. The impact, if any, of this sensing level is unclear at this time. The designed voltage gradient is safely below the 1.65 volt maximum body voltage gradient suggested by the Department of Fisheries, Canada. Snettisham The electrode proposed at Snettisham would be located in the bight across the bay from the Snettisham power station. This bight is adjacent to the site of the Snettisham pulp mill. Depth is 300-350 feet offshore. A strong halocline is likely between surface and deeper waters. The electrode would be located about 200 feet deep, probably below the halocline. The bight is fished by one vessel (F.V. Seadawn, Juneau) for shrimp, probably "side stripe." According to Tim Koeneman, ADF&G, this resource is probably limited in extent. Immediately down channel (southwest) of the proposed electrode location a line of king crab pots are seasonally set. Magnitude of catch was not estimated. There is a run of capelin (eulachon) which spawns at the mouth of the Speel River in early May. The location(s) and depths where this population may hold in the estuary are not known. Test trawls have shown this species to be dispersed vertically for 20-30 fathoms, but their depth before spawning is not known. No information is available which describes the route(s) outmigrating salmon fry and smolt take out of Port Snettisham. Dittier (ADF&G) believes these spring migrants are likely to move rapidly out of the inlet, carried by rising meltwaters from Speel River. He further believes their route of travel will be highly variable according to prevailing conditions of tidal and river flow at the time of outmigration. It should be borne in mind that this, our most qualified opinion, is not yet supported by actual observation of fry or smolt in the inlet. The route(s) through Port Snettisham of adult salmon returning into Speel River and the Snettisham hatchery are also unknown. Occasional feeding king salmon may move in and out of Snettisham. Their depth would reach the 200 foot level proposed for the electrode. Halibut are not caught to any extent in Port Snettisham. Approximately 50 harbor seal live in the Port Snettisham area. They feed on salmon moving into Speel River, and congregate in the head of the bay when capeline (eulachon) are running in early May. Sea lion may occasionally be seen at that time. Only one whale (humpback) has been reported in recent years. Petersburg The electrode at Petersburg would be located in Frederick Sound along the shore ENE of town, offshore from Sandy Beach Road. The electrode depth would be found at something less than 2,000 feet offshore. There is a residential area along this shoreline, and an 1,100 foot sewer outfall extends out to a depth of about -62 feet below 0 tide. The sewer line is made of asbestos-concrete. Alascom cables emerge along this shoreline. Their location was not closely identified. This portion of Frederick Sound is not protected from winds and storm seas. Few vessels other than Alascom ships anchor here. Waters in this area are fished for crab, coho and chinook salmon, halibut, and octopus; evidently, none of these species are taken in large number. A fisheries biologist, resident along this shore, also suspects that "nomad" coho salmon pushed out of nearby streams may pass along this shore to enter small rearing streamlets along the shoreline. Although seal and sea lion undoubtedly use these waters, there is no report of significant concentrations. Wrangell The Snettisham-Ketchikan Transmission System Preliminary Feasibility Study indicates that the sea electrode would be located somewhere between Cemetary Point and Shoemaker Bay, south of Wrangell in Zimovia Straits. Distance from shore to 200 foot depths will be about 3,000-4,000 feet, well into the Strait. Two sewer outfalls, both constructed of ductile irons, occur along this shoreline. A Wrangell outfall is located near Cemetary Point, and extends to the -25 foot tideline. There is another line from the former Wrangell Institute which extends to the -5 foot tideline. These waters support sizeable stocks of shrimp, which are commercially harvested. Zimovia Strait is also a likely corridor for juvenile salmon migrating seaward and returning adults. No information was obtained regarding uses of these waters by sea mammals. Ketchikan The preliminary feasibility study does not specify a location for a sea electrode near Ketchikan, but suggests in a drawing that its location might be in Tongass Narrows in the vicinity of Mud Bay and Ward Cove. The Revilla Island shoreline in this general area is thoroughly developed with much boat use, storage, etc. The center of Tongass Narrows in this area lies about .6 to .7 miles off the shorelines. These waters in Tongass Narrows are not heavily fished, and were not extensively evaluated in this regard. The waters off Point Higgins (northerly end of Tongass Narrows) and Vallenar Point (across Tongass Narrows from Point Higgins) were considered since these locations are more free of development and possible corrosion impacts from a sea electrode. Waters moving northeast of Point Higgins on into Clover Pass become increasingly heavily used by sport fishermen, particularly for coho and chinook salmon, but also for halibut and rock fish. The immediate vicinity off Point Higgins is less used by fishermen. Waters off the Gravina Island shoreline immediately south of Vallenar Point are fished by commercial trollers. The mouth of Vallenar Bay, about two miles south of Vallenar Point, is sometimes used as an anchorage for ships waiting to load or unload in the Ketchikan vicinity. Chlorine Gas Production from Anode Electrodes As with other elements of this work, investigation was directed at two fronts: biological effects of marine chlorination (found in Appendix A) and the probability of chlorine production and possible concentrations at the electrodes. The latter effort was unsuccessful in establishing a rigorous physical model for estimating chlorine concentrations, but did indicate that measureable chlorine concentrations at the electrodes are unlikely. Communication with Mr. John McKinney of Duriron (electrode) Company of Dayton, Ohio, indicated that in a marine environment, where electrodes are not bedded in the bottom, chlorine is immediately diluted into seawater with no measure- able chlorine expected in the area. B.C. Hydro has an electrode installed in a ground-bed, where anodes are placed a few feet into the ground. This results in non-circulating water a around the anode. In this instance chlorine produced at the anode can accumulate. As a result, there is some effect on nearby plant life. Mr. McKinney (Duriron) knows of no studies or information which would quantify chlorine production from Durichlor anodes. Mr. Ken Williams of Norton Corrosion, Ltd., noted that chlorine production from anodes depends on temperature, pressure, composition of anode, as well as current density (amperes/cm-) at the electrode. He, also, would not expect measureable chlorine to form in a sea electrode system, especially at the low operating amperages anticipated. Williams cited the situation where a cathode protection system is installed in Seward, Alaska, using a Durichlor anode in the sea to protect a 5,000 A current system from corrosion. He notes that barnacles and algae grow around the anode. Thus, while it is evident from the review of literature dealing with marine chlorination that damaging biological effects can be expected from even low concentrations of chlorine, there is indication that such concentrations do not develop beyond the immediate near-surface of the anode. Chlorine production from sea electrode-anodes is unlikely to be an environmental problen. Corrosion Effects on Ships and Shore Facilities An extensive body of relevant information titled "A Survey of Corrosion Aspects Related to the Operation of Electrodes for HVDC Ground Return," received from Allmaénna Svenska Elektinska Aktiebolaget, provides a basis for evaluating possible impacts from corrosion. This report is included as Appendix B. As part of the scope of this effort, we have considered the conditions near the possible electrode sites as they may relate to corrosion effects (refer to Ground Current Electrode Section). The objective of this review was to identify areas where corrosion effects may require more intensive study. Snettisham The electrode in Port Snettisham would be located somewhat less than 2 miles from the powerplant-hatchery-living area complex. This installation is presumed safe from significant corrosion impacts, either as it stands or with installed cathodic protection. Petersburg The vicinity of proposed electrode location near Petersburg is not significantly used by vessels for anchorage since the area is unprotected. Existing features that may require further examination will include: 1) The 1,100 foot sewer outfall (18 inch concrete) which runs out to a depth of -62 feet. 2) Private or public water lines found along Sandy Beach Road. Wrangell The shoreline south of Wrangell, between Cemetary Point and Shoemaker Bay, may experience corrosion effects from an electrode located in offshore waters. Features of concern include: 1) The two ductile iron sewer lines running out from Cemetary Point and the former Wrangell Institute, respectively. 2) The boat harbor facility near the former Wrangell Institute. 3) Present and contemplated sewer/water lines serving residences along the road south from Wrangell. Ketchikan The sea-electrode near Ketchikan must be located with consideration to the extensive residential and business developments along the NE side of Tongass Narrows. This shoreline is also heavily used for a variety of marine activities, particularly boat storage and repair. Additional possible electrode sites which should be examined include the vicinities of Point Higgins, and Vallenar Point on Revilla and Gravina Islands, respectively. The Point Higgins location might affect the pipes, wells, etc., of a number of residences. The Vallenar Point location would have little evident problem with corrosion effects. Magnetic Field Alteration by Submarine D.C. Power Cable and Effects on Sea Life The natural conditions and the variability of the earth's magnetic field are discussed briefly in Appendix C. The horizontal component of the geomagnetic field (which is the component selected for examination here) amount to about .15 to .16 gauss and may vary during a magnetic storm by at least .01 gauss (ca. 6%). The horizontal component of the magnetic field developed above the proposed DC line can be computed as follows: where r = distance above DC line and I current in amperes Ayo is given in A/m. Equivalent value in units of gauss = = . In this manner, the following conditions of induced magnetic field above the DC line are proposed: Distance Above DC Line (m) A/m Gauss at 0.1 453.53 5.68 at 1.0 45.353 568 at 10.0 4.535 -057 at 20.0 2.267 028 at 100.0 453 -006 The net effect of the DC power line's magnetic field in altering field lines near the line will be greatest when the line runs along an azimuth of about 210°T and least when the line runs at an azimuth of 120°T. Thus, there will be small, but measurable, differences in magnetic field characteristics between Stephens Passage and Frederick Sound and between the lines down Stikine Strait and Clarence Strait. - A summary of the physical-biological conditions along the proposed DC cable route is also necessary for this evaluation. The proposed location for the -10- entry of the line into Port Snettisham waters is in the bight just south of Star Point. No particular habitat or holding area has been identified for this location, though the site has never been examined from this perspective. The line would move through Port Snettisham to Stephens Passage at depths initially exceeding 250 feet then increasing to depths generally exceeding 600 feet. No fish habitat was identified along this section. The line as it moves down Stephens Passage maintains depths greater than 600 feet and frequently exceeds 1,000 feet. It may pass in the general vicinity of waters and bottom habitat fished for halibut, brown crab, and black cod. A sizeable black cod "hole" is located just south of the "Brothers," west of Cape Fanshaw. This "hole" is partly crossed by the charted cable corridor. The cable's route down Frederick Sound to Petersburg’s east shore passes through depths varying from 350 to nearly 600 feet. No particular habitat was identified for this section, though these waters*are extensively fished for crab and halibut. The cable would emerge at Petersburg along a shoreline which supports harvestable numbers of crab, halibut, and octopus. Significant numbers of troll-caught salmon are also harvested in these waters, and the area may also receive some use in spring by migrating salmon fry or smolt. Entry of the DC cable into Zimovia Strait near Wrangell would be more gradual and would initially reach depths of only about 200 feet. This area, where Zimovia Strait is crossed, is one of the more important shrimp habitats in S.E. Alaska. As the cable passes through Chichagof Pass, waters deepen, ranging from 350 to 500 feet. No specific habitat was identified for this section of the route. The cable moving through Stikine Strait would pass under depths of 600 to 1,200+ feet. No specific habitat was identified for this sector. The route of the cable along Clarence Strait would be through depths of 600 -1ll- to 2,000+ feet in passing from Stikine Strait to the northerly end of Tongass Narrows near Ketchikan. These waters are extensively fished for halibut and at least one black cod "hole" (at the mouthiiof Ernest Sound) is intersected by cable corridors. The emerging route of the DC cable near Ketchikan could pass through waters utilized by feeding coho and chinook salmon, and through shallow waters which may be used in spring by migrating salmon fry and smolt. An examination of possible biological impacts from this proposed underwater DC cable, based upon the foregoing physical-biological features and utilizing the literature study (Appendix A), can be attempted in a general sense only. Some conclusions reached by this investigator are as follows: 1) Large-scale disruption of any biologic community or habitat encountered by the magnetic field of the DC line is unlikely. Disruption, alteration or even enlargement of very local and small biologic communities is possible. 2) Change in the biota inhabiting the immediate environs (0.1 to 1.0 m radius) of the cable is likely. The nature of this change, whether depressing or stimulating a given population's growth or reproduction patterns, cannot be accurately evaluated at this time. 3) Migratory behavior of fishes, notably salmon, could be altered by the influence of the DC cable's magnetic field in the near-field. The only locations where this, as yet undocumented, possibility has much chance of occurring is where the cable passes from the sea bottom to the adjacent shoreline (Snettisham, Petersburg, Wrangell, Ketchikan). Such an alteration of migration behavior of salmon could occur at either outmigration (fry, smolt) stage or when adult salmon return. The low current load, and hence low magnetic field effect of the proposed DC line, minimizes the probability of such a effects. —j3- Magnetic Field Alteration and Effects on Navigation by Magnetic Compass The physical background described in the previous section is pertinent for this section also. Equally pertinent is Appendix 1F of the "Snettisham- Ketchikan Transmission System Preliminary Feasibility Design." Examination of charts along the cable route and evaluation of depths in terms of Appendix Figure F-4 indicates that only in the crossing of Zimovia Strait will compass alteration even approach 2°. Even this local compass alteration must be viewed in terms of the natural changes of magnetic compass variation. As summarized in Appendix C, it can be shown that magnetic compass variation may change up to 5-6° during magnetic storm disturbances. It is also true that variation may change from day to day by up to a half-degree or so without the occurrence of magnetic storm events. In conclusion, as indicated in the earlier "Preliminary Feasibility Design" report, there will be no significant problem with compass change due to the DC power line. Location of Submerged Cable and Effect on Anchoring or Fishing Areas Here, too, the physical background information provided in previous sections will be used as a basis for this work. Fishery observations described earlier will also be considered. The anchoring possibilities evident from examining the charts along this route include the following: 1) Proposed cable entry near Snettisham. 2) Proposed cable emergence near Petersburg. 3) Proposed cable routing across Zimovia Strait. None of these locations offer much likelihood of risk to the cable. Risk from fishing may be considered in three categories: 1) Long line fishing for halibut, black cod: This method will utilize line with maximum test of around 1,000 lbs. Fish lines will break before the power line is disrupted. -13- 2) Pot fishing for black cod and other bottom fish species: This gear will utilize greater breaking strength, but is not likely to hang up with a cable on the bottom. 3) Bottom trawl fishing: Mr. Barry Bracken, S.E. Alaska bottom fish biologist for ADF&G, indicates that trawl fishing in inside waters is not likely, and if this method is employed, it is more likely to be mid-water trawl than bottom trawl. Construction Impacts Construction impacts by roading or by trenching to bury the D.C. lines near shores have received little attention during this work. It is a feature which must receive attention at the stage where advanced study and deliber- ation is given to cable entry locations and to electrode locations. At this stage of information, significant evaluation proves unfeasible, although serious problems are not anticipated in this regard. RECOMMENDATIONS | | gi a gi a a wg a a a a These recommendations are provided in order of the priority we would establish: 1) Perform biological inventory work in the vicinities of locations where the D.C. power cable may enter salt water and where the sea electrodes would be located. This work will identify populations and habitats in the vicinity of proposed installations. It will be used to: a. assess magnitude of possible impacts, b. locate installations where least impacts are possible, and, c. provide a basis for future re-examination and evaluation of possible effects on installations on sea life. This inventory should include at least three visits to each site (fall, winter, spring). A fourth visit (summer) would provide more conservative and complete coverage. Work in each area should include the following items as a minimum: a. identification of fish as found in the area; estimate of numbers within populations b. identification of shell fishes using each area, with estimates of numbers c. identification of flora/fauna on the sea bottom of area. This TA. wn work should include photographic or video record of bottom surface conditions d. prominent in-fauna species found within the near-surface of the sea bottom e. salinity/temperature profiles descriptive of the area. Such a program of investigation was discussed with the U.S. Fish & Wildlife Service (FWS), since this Service has done, and is equipped to do, such work. This discussion led to an estimate of costs per area visit. Methods used by the FWS for such work would include: trawl, trap (for shell fishes), dive (scuba) observation, B/W video observation & record, in-fauna (within bottom) 6-inch core sampling, salinity/temperature profiles. Cost per day for this work would be about $500. A given area (i.e. electrode site) would require about five days work. Seven to eight days would be required for each visit where possible areas for both electrode and cable entry are located in close proximity and can thus be combined. This would be true in the cases of Snettisham, Petersburg, Wrangell, and possibly true for the Ketchikan locations, as well. Additional laboratory time would be required for analyses of in-faunal species found in 6-inch core samples. This analysis is estimated to cost $1,000 per area core sampled. Thus, an estimate of biological inventory costs for a periodic visit to one set of electrode-cable entry areas would be as follows: 8 days: $4,000 core analysis work _1,000 $5,000 per visit to combined electrode and cable entry areas. Cost per seasonal round of visits to the four locales in question (Snettisham, Petersburg, Wrangell, Ketchikan) would be about $20,000, and a year's cost with quarterly visits: $80,000. The analysis and report preparation upon completion of this work would cost about $10,000. In the event that phasing out this environmental work concerning electrode-cable entry sites proves desireable or necessary, the following factors should be considered in prioritizing locations: -15- 2) a. Areas of highest biological potential should receive first attention. This will allow agencies maximum time and experience in dealing with possible critical areas or features which may be identified. b. Operability - Among areas of similar biological potential, areas easiest to investigate should be examined first. As examples, areas with strong currents or turbid (glacial) waters may be deferred if other sites of equal productive potential are also being considered. c. Logistical situation is not anticipated to be an important factor in prioritizing southeastern sites. Vessel use could often be scheduled so that only a relatively small additional cost is involved in varied locations. Timing of work may also be an important consideration. Spring (April) is suggested as a desireable time to begin environmental site investigations due to long daylight hours, favorable weather, good water clarity. In the instance of the proposed Snettisham-Petersburg-Wrangell- Ketchikan linkage, it appears that Wrangell and Ketchikan may have the highest biological potential and, hence, highest initial priority. The Wrangell (Zimovia Straits) area is known to have a shellfish population of significant size, and probably supports other species as well. The Ketchikan area (Pt. Higgins, Vallenor Point) has not yet been well defined regarding proposed cable/electrode locations. A high priority given to this area is based upon the existence of known, nearby populations of known importance. Either of these areas are likely to be operable. The Zimovia Straits area may be subject to milky water (at the surface) during some tidal conditions of the meltwater season between May-June:and November. Both sites probably have significant current conditions, with Ketchikan perhaps being more severe. A study of corrosion hazards along shore areas near sea electrodes will be necessary. The most important areas will be near Petersburg, Wrangell, - and just northeast of Ketchikan, if a sea electrode location is consid- 16 3) ered within Tongass Narrows. This study would be of an engineering nature, and may involve a summer's work. Location and evaluation of bottom fish and shellfish resources with respect to proposed routings for the submarine cables will provide a basis for locating the cable so as to avoid areas of existing or potential fishing importance. This effort will serve to avoid hang- ups of fishing gear on the D.C. power cable, as well as reduce or eliminate possible electro-magnetic effects upon fishery resources caused by the cable. The work described below should begin after developing proposed routings of the submarine cable, utilizing more than one alternative where practical. It should be three-fold in nature: . a. Charts showing alternative routings should be discussed in detail with bottom fish specialists in ADF&G, NMFS. This work should lead to initial identification of known or likely fishery resources in the vicinity of cable routings. b. Personal contact should be made with fishermen engaged in bottom fishing along the proposed routes. These contacts should be made either individually or in local gatherings and should lead to further refined and/or additional locations of existing or poten- tial fishing areas. This work may involve somewhat confidential information requiring special methods of acquiring and handling. c. Locations obtained from (a) and (b) above should be plotted on charts. Specific areas of possible concentrated resource values which cable routings cannot avoid may require test fishing. Estimated time required for this work is given as follows: a. 3 days; b. 5 days; c. 2 days, +5 days test-fishing possible. Report preparation; 5 days. Thus, 15 investigation + 5 days fishing. Estimated cost: 15 days investigation $7,000 fishing (possible) 3,000 , - $10,000 =. TF = 4) 5) Examine proposed roading, trenching, and shoreline disturbance sites for possible impacts and/or mitigation measures. This work should be done when more specific information is available on the location and nature of proposed installation activity. It involves on-site visits, but should not require an extensive time period. Studies of electro-magnetic effects on migratory behavior and migra- tory success of salmon, both as outmigrating young and as returning adults would be relevant to the installation of HUDC submarine cables. Although such studies are probably unjustified in terms of this project, the questions which might be answered will recur in future projects involving electro-magnetic field effects in the sea. This may be partic- ularly true if and when much larger current loads are carried in a sub- marine DC line. The environment and the circumstances found at Port Snettisham - strong natural magnetic anomaly in the vicinity, presence of native salmon runs, presence of salmon hatchery, possible availability of electrical power, reasonable access - suggest that a specialist in this field of study might be able to design productive work here. Inquiry should be made of biologists working in this field to deter- mine whether the Snettisham location has, in fact, the particular research potential suggested. If such potential is identified, coop- erative work involving scientists and appropriate agencies could be encouraged. Such work should not be tied to this project. It would probably in- volve a time frame of several years, and the support of several agen- cies or institutions. Daniel M. Bishop October 29, 1981 2B APPENDIX A SCOPE OF BIOLOGICAL EFFECTS FOR THE PROPOSED D.C. POWER GRID: LITERATURE REVIEW AND BIBLIOGRAPHY Janice C. Mills - Juneau, Alaska October 15, 1981 19 TABLE OF CONTENTS for APPENDIX A BIOLOGICAL EFFECTS OF DIRECT CURRENT FIELDS IN THE MARINE ENVIRONMENT INTRODUCTION... . . a Ba SF & BASIC ELECTRICAL FIELD PRINCIPLES eee eee Size of Organism ..... Species . 2. 1. 6 2 es ee ee ww ew ww Water Resistivity... ea © @ THRESHOLD OF ELECTRICAL SENSITIVITY ee 6.6 « ATTRACTION AND AVOIDANCE EFFECTS ....... Attraction to the Anode ......... Salmonids ...... oe . Other Aquatic Organisms ...... Repulsion from the Cathode ....... NARCOSIS, TETANUS AND DEATH ........ Salmonids .......-e- Other Aquatic Species. . os s BEHAVIORAL EFFECTS OF ELECTRIC FIELDS Orientation and Navigation ....... BIOLOGICAL EFFECTS OF MAGNETIC FIELDS IN THE MARINE ENVIRONMENT INTRODUCTION... ‘om 3 ws # 2H mH ww PHYSIOLOGICAL EFFECTS | cee eee EFFECTS ON ORIENTATION AND NAVIGATION. oe BIOLOGICAL EFFECTS OF MARINE CHLORINATION INTRODUCTION... . . AQUATIC LIFE CRITERIA. FOR CHLORINE . DEGRADATION OF CHLORINE IN SEAWATER ..... CHLORINE TOXICITY TO MARINE PLANKTON. .... CHLORINE TOXICITY TO BENTHIC ORGANISMS . . . CHLORINE TOXICITY TO FISH .......4-.-.-.- BIBLIOGRAPHY ELECTRIC FIELDS .....+4.4446-. MAGNETIC FIELD EFFECTS ........ SEAWATER CHLORINATION ......-.-. 20 24 24 24 25 25 26 27 27 27 28 29 30 30 32 32 33 34 34 aS 40 40 41 43 43 46 49 63 71 INTRODUCTION A review of the biological literature was conducted to identify the scope of potential biological effects resulting from submarine direct current electrical transmission from Snettisham power station (near Juneau, Alaska) to Ketchikan, Alaska. Elements to be considered during the literature search included: 1) Effects of electrical fields associated with the ground sea electrodes on salmonids and other aquatic organisms. 2) Impact of magnetic field alteration along the DC cable on the physiology of aquatic organisms and on the orientation and navigation of migratory salmon. 3) Effects of seawater chlorination on marine life. Computer searches of the literature were conducted through services available at the Alaska State Library, Juneau, and the University of Alaska Rasmussen Library, Fairbanks. Indices searched included Aquatic Science Abstracts 78-81/July, BIOSIS Previews 77-81/Sep., Compendex 70-81/Aug., Inspec. 78-81, and Pollution Abstracts 70-81/May. A manual search was also conducted of the Aquatic Science and Fisheries Abstracts 70-81/July. Combinations of the following descriptors were used in the search process: Behavior Chlorine or chlorine gas Electric Electric field Fish or fishes Magnetic Magnetic field Magnetic field and compass Magnetic force 2A: Marine mammal Marine organism Mortality Navigation Power plants Salmon Sea lion Sea mammal Seal Submarine power cable Whale These descriptors were also used in subject heading searches in the holdings of the Alaska Library Network, the University of Alaska at Juneau, and the National Marine Fisheries Service Library at the Auke Bay Laboratory. The literature, search was expanded by obtaining and reviewing pertinent articles cited in the bibliographies of all material examined. Individuals 1) 2) 3) 4) 5) 6) Mr. Dr. Dr. Mr. Mr. Mr. contacted for information as part of the search effort included: Jon Dunlap B. Kepshire Uno Lamm John McKinney Willis Osbakken Jim Patchett Electric Power Research Institute Palo Alto, California Principal Fish Culturist-FRED Division Alaska Dept. Fish and Game Juneau, Alaska Consultant to ASEA Hillsborough, California Duriron Company Dayton, Ohio Chief, U.S.G.S. Sitka Observatory Sitka, Alaska Bonneville Power Portland, Oregon 22 7) Mr. Tom Pittman U.S. Bureau of Mines Douglas, Alaska 8) Dr. Thomas Quinn College of Fisheries University of Washington Seattle, Washington 9) Mr. S. Smedsfelt Chief Engineer The Swedish State Power Board 10) Mr. Ken Williams Norton Corrosion, Ltd. Woodinville, Washington 11) Dr. Bruce Wing Biological Oceanographer Auke Bay Laboratories Auke Bay, Alaska 12) Mr. Greg Young Fisheries Biologist Salmon Creek Hatchery Juneau, Alaska The following review and bibliography describe the literature relating to effects of electric fields, magnetic field alteration and chlorination on the marine environment. Literature which could be obtained locally or through interlibrary loan, as well as abstracts generated by computer search, were annotated in the bibliography. Articles which were not available, but which were reviewed and cited elsewhere or appeared particularly relevant, were included as non-annotated citations. For the purpose of evaluating the potential for impact of the Snettisham- Ketchikan line, emphasis was placed on reporting levels of intensities and concentrations which will have lethal and sublethal effects on marine organisms. Most frequently, the identified thresholds of impact exceed those anticipated for the proposed transmission line. 23 BIOLOGICAL EFFECTS OF DIRECT CURRENT ELECTRIC FIELDS IN THE MARINE ENVIRONMENT INTRODUCTION Physical reactions of aquatic organisms exposed to electric fields have been the subject of considerable experimentation, particularly as they relate to the development of electric fishing techniques and fish diversion designs. Scheminsky (1934) outlined the following general reaction sequence for fish subjected to electric currents of successively higher energy levels: 1) Threshold of sensory recognition, 2) Attraction and avoidance effects, 3) Narcosis (muscle relaxation and paralysis), 4) Tetanus and mortality. This sequence is a simplification of more than 30 distinct physiological reactions identified for aquatic organisms exposed to fields of increasing intensity (Lamarque, 1967). Additional biological impacts may include various nonphysio- logical effects, such as interruption of electrocommunication, orientation and electronavigation, and detection of predator and prey organisms. BASIC ELECTRICAL FIELD PRINCIPLES The reaction of an organism in the proximity of an electrode depends essentially upon the character of the electric field, the distance between the organism and the electrode, and the orientation of the organism in the field. However, additional modifying factors which influence the degree of exposure and the potential for biological effects are described in the following sections. Size of Organism Holzer (1932) applied the term Gestaltspannung (body-voltage) to the difference of electrical potential between the head and tail required to produce a reaction to an electric field. Larger fish intercept a greater head-tail 24 potential than smaller fish in a given voltage gradient and, therefore, charac- teristically exhibit lower tolerance to an electric field (Halsband, 1967). Body-voltage is also a consideration in evaluating effects of varying body orientations in the electric field. Orientation parallel to current flow maximizes the head-tail potential and results in the most sensitive response. Reactions to electric fields lessen (Klima, 1968; Enger, et al., 1976) or disappear entirely (Rommel and McCleave, 1973a; McCleave, et al., 1971) when organisms are oriented perpendicular to current flow. Species As will become apparent in later sections, thresholds of response to electricity are species-specific and are related to methods of electroreception, body resistivity, life stage and ecological behavior. Water Resistivity The body-voltage experienced by an aquatic organism in an electric field is influenced by the ratio of water resistivity to that of the organism's body (Holzer, 1933 cited by Denzer, 1956). In an electrically equivalent surrounding (where the water and organism are equally conductive) the head-tail potential in a homogeneous field is equal to the voltage gradient multiplied by the organism's length. When the water resistivity exceeds that of the body of the organism, current lines are deflected toward the body (the better conductor) and the body-voltage is lower than in an equivalent medium. In seawater, the water is much more conductive than the organism, and the body deflects the current flow. Therefore, the body-voltage experienced by an organism in seawater is greater than in an equivalent medium. The resistivity of both body tissues and water decrease with increasing temperature. A potential gradient which has minimal effects on an organism in cold water (high resistivity) might be sufficient to narcotize or kill the same organism in warmer water. Such contrasting effects have been reported based on field observation by Erkkila, et al. (1956) who noted that game fish were unaffected by an electrical field in cold months, but were killed when subjected to identical voltage gradients in summer. 25 The organism's body resistivity is species-specific and depends upon the body chemistry, internal structure and surface conformation. Halsband (1967) calculated resistance for several types of fish, including trout (818 ohm-cm), perch (981 ohmcm), carp (1,149 ohm-cm) and gudgeon (1,228 ohm-cm). THRESHOLD OF ELECTRICAL SENSITIVITY Several species of aquatic life, both fresh and seawater varieties, have the ability to detect weak electric fields which may be useful for detecting prey and predators, communicating, and assessing changes in water chemistry, currents and geomagnetic and geoelectric events (Bullock, 1973). The sensitivity of many organisms to feeble electric gradients may make them sensitive to natural or man-made electrical events of less magnitude than those which produce detectable physiological effects. Electrosensory abilities were first recognized in fish which had identifiable receptor organs. Kalmijn (1966) first demonstrated the electrosensitivity of the ampullae of Lorenzini, structures which are widespread in the skin of all elasmobranchs (sharks, skates and rays). The long tubules of the ampullae magnify the difference between the electrical potential of seawater at the pore opening and the body potential within the fish. Elasmobranchs are sensitive enough to detect objects over a range of several meters, with a threshold of electrical sensitivity of 1 x 107 >mV/cm in seawater (Kalmijn, 1966). Until recently, electroreception was discounted for most teleost fish (Bullock, 1973). However, passive reception of feeble voltage gradients is now accepted for freshwater fish with small pit organs, such as catfish (Peters and Van Wijland, 1974); American eels (McCleave and Power, 1978); several families of electric fish (Lissmann and Machin, 1958) and lamprey (Podznick and Northcutt, 1981). Sensitive electroreception has also been demonstrated for some species of salmonids. McCleave, et al. (1971) tested 18 Atlantic salmon (Salmo salar) for conditioned cardiac deceleration responses to weak electric fields in freshwater. Ninety percent of the salmon demonstrated significant response to voltage gradients of 0.06 to 0.70 mV/cm when the field was applied 26 perpendicular to the body axis. In seawater (resistivity 40 to 400 ohm-cm) Atlantic salmon were found to be sensitive to direct current voltage gradients of 6 x 10> mV/cem (Rommel and McCleave, 1973b). No investigations are known which specifically identify electrically sensitive organs in salmonids. However, in a review of sensory function in fish, Dijkgraaf (1963) concluded the electroreceptive organs in other species are basically modified mechanoreceptors which have evolved electrical sensitivity independently in several groups. The possibility exists of a system of electroreception developing in any group of fish that has sensory organs possessing even secondary electrical sensitivity (Royce, et al., 1968). Perception of direct current voltage gradients as low as 0.001 mV/cm has also been demonstrated for several non-fish species, including the planaria Dugesia (Brown, 1962) and the snail Nassarius obsoleta (Webb, et al., 1961). ATTRACTION AND AVOIDANCE EFFECTS Attraction to the Anode The involuntary movement of fish toward a positive electrode (anode) in a continuous direct current field has been exploited since the 1950's for electrofishing in freshwaters of Europe and North America (see bibliography by Applegate, et al., 1954). Lamarque (1967), in a study of 16 freshwater fish species, described the response of fish to the anode as follows. In an increasing anode field, an organism experiences (1) increased activity and "forced swimming" in a random direction, (2) narcotic inhibition of activity (see following section), and (3) erratic, "unbalanced swimming" toward the anode. During the narcotic state and unbalanced swimming phase, the organism involuntarily orients its head toward the anode through enforced curvature of the body and can escape only passively (i.e., with current drift) from the anode field. Increased activity during stages (1) and (2) may be accompanied by changes in normal oxygen consumption and metabolism (Altmann, 1969). Salmonids Lamarque (1967) documented forced swimming in the anode field at a voltage gradient of 136 mV/cm for a 20 cm trout in freshwater. The duration of forced 27 swimming was longer for salmonids, which are naturally strong swimmers, than for the less capable swimmers tested. The threshold voltage for unbalanced swimming toward the anode occurred at 870 mV/cm. For a trout oriented perpendicular to the electric field, anodic curvature of the body (which reoriented the fish to face the anode) occurred at 350 mV/cm. In freshwater laboratory and field tests with a pulsed DC field (duty cycle 0.66, pulse rate 3/sec.), McLain and Nielsen (1953) demonstrated involuntary and persistant movement toward the anode for brook trout (Salvelinus f ffontinalis) and rainbow trout (Salmo gairdneri). Trout of various body lengths (9 to 24 inches) responded to voltage gradients less than 393 mV/cm, with larger fish showing greater sensitivity. However, trout will show a less sensitive response to continuous DC fields than for the pulsed current used in this study (Haskell, et al., 1954). Thresholds of response for salmonids in seawater can be expected to be lower than indicated in these freshwater studies due to the low resistivity ratio of seawater to the fish's body. In the marine environment, studies connected with the U.S. Navy's Project Sanguine (renamed Seafarer) investigated the biological effects associated with low level alternating current (AC) electric fields. McCleave, et al. (1974) and Richardson, et al. (1976) investigated possible effects of extremely low frequency AC fields on Atlantic salmon. Conditioned cardiac deceleration techniques demonstrated that although Atlantic salmon are marginally sensitive to AC fields of 0.07 to 7.0 mV/cm (frequency of 60 to 75 Hz), locomotor activity levels were unchanged at these voltage gradients. Anodic electrotaxis did not occur during these studies with AC fields, and the potential for effects would be even less for DC fields. Other Aquatic Organisms Field tests of marine effects associated with a 200A direct current transmission line were conducted in 1948-49 by the Swedish State Power Boerd and the National Board of Fishery in Vastervik, Sweden. Fish (pike, cod, perch, eels, bream, roach and herring) held within 2m of the anode became unconscious at the instant of current closing, but recovered after current breaking. When active, fish were continuously striving toward the anode. No attraction effect was noted for fish held at 4-10m distance from the anode cr in free schools of fish in the vicinity (S. Smedsfelt, pers. comm.). Voltage gradient was not specified. 28 Zimmerman and McCleave (1975) and McCleave, et al. (1971) reported that polarity and strength of a weak DC electric field influenced orientation in American eel elvers (Anguilla rostrata). Additional studies by McCleave and Power (1978) indicated that at the lowest field strengths tested in seawater (1 x 10> to 1x 107 >nV/cm) elvers turned more toward the cathode (negative electrode) while at higher fields (0.91 to 0.1 mV/cm) they oriented toward the anode. Klima (1972) observed fish reactions to different voltages and pulse rates of interrupted DC fields in the laboratory and documented electrical characteristics which induced electrotaxis in 12 species of pelagic and bottom fish collected in the Gulf of Mexico and tropical Atlantic. Effective electrical combinations varied according to species and body length, and ranged from 150 to 300 mV/cm (frequency 15 to 45 pulses/sec., pulse duration 1.0 msec.). Electrotaxic behavior included an increase in swimming speed and distance traveled by the fish in the anode grid. Evidence presented by Lamarque (1967) indicated that some species of bottom fish may flatten to the bottom rather than undergo the forced swimming electrotaxis phase. Repulsion from the Cathode Organisms which venture into a negative electrode (cathode) field are generally repelled and reorient their direction of movement away from the electrode. This effect has been utilized in some electric screen and fish diversion designs, where the cathode produces a negative voltage gradient in the nearfield and the anode is generally of infinite extent and has no local field effect (Hartley and Simpson, 1967). Larmarque documented a half-turn away from the cathode at a direct current voltage gradient of 130 mV/cm for a 20 cm trout in freshwater. Similarly, in freshwater field tests, rainbow trout which had been drawn to the anode at a voltage gradient of 165 mV/cm were immediately repulsed from the electrode when polarity was reversed (McLain and Nielsen, 1953). In field tests of the 200A direct current submarine transmission system at Vastervik, Sweden, fish held within 2 m of the cathode were continuously striving to move away from the negative field. No effects were noted for caged or free schools of fish at distances greater than 2.5 m (S. Smedsfelt, pers. comm. ). 29 Contrasting orientation effects have been noted for some species in the cathode field. Paulini, et al. (1968) studied the behavior of manorbid snails (Biomphalaria glabrata) under the influence of pulsed direct current (frequency 1 to 2 Hz). Snails migrated to the cathode at current densities of 0.08 to 0.12 mA/ cn’. An increase in current density caused the snails to retract into their shell and, in some cases, induced bleeding. Novak and Bentrup (1973) subjected zygotes of the marine brown alga, Fucus serratus, to a continuous DC field. In a voltage gradient of 300 to 400 mV/cn, zygotes oriented the cell axis parallel to the field, with the rhizoid pole oriented toward the cathode. NARCOSIS, TETANUS AND DEATH In the narcosis zone of a direct current anode field, an organism will experience relaxation of the body musculature and paralysis. If the immobilized organism is passively carried into a higher voltage gradient, it will resume activity and swim involuntarily toward the anode. This may carry the organism into a voltage gradient sufficient to induce tetanus, which may cause fractured vertebrae, rupture of internal organs and drowning (Lamarque, 1967). Either involuntary active movement toward the anode or immobilization near the anode will increase the likelihood of death, as adverse effects of voltage gradient increase with increasing duration of exposure (McMillan, 1928; Collins, et al., 1956). In a cathode field there is no narcotic effect, although an organism which is exposed to high voltage gradients in the negative field will be subject to cathodic tetanus. In a gradually increasing voltage gradient, however, the organism will generally turn away from the cathode before a body-voltage sufficient to cause tetanus is intercepted. Salmonids In freshwater experiments with 20 cm trout, Lamarque (1967) documented thresholds of 350 mV/cm for anodic narcosis and 870 mV/cm for anodic tetanus. Cathodic tetanus was elicited at a voltage gradient of 350 mV/cm. 30 In a detailed study of the factors affecting the mortality of chinook salmon fingerlings (Oncorhynchus tshawytscha) exposed to pulsating DC fields, Collins, et al. (1956) evaluated the influence of voltage gradient, current density, other field characteristics, fish size, and water temperature. Mortality increased in a constant ratio with an increase in voltage gradient and/or current density. The effect of voltage gradient increased with the duration of exposure. No mortality was induced at voltage gradients less than 4000 mV/cm and current densities of less than 0.19 mA/em in water of high resistivity (21,000 ohm—cm). In seawater tests of AC electrical fish screen designs, fingerling chinook salmon 3.1 inch (7.9 cm) in length were narcotized when exposed to a voltage gradient of 106 mV/cm (McMillan, 1928). Exposure to a gradient of 590 mV/cm for 1 minute resulted in death, and a direct relation of mortality to duration of exposure was noted. The possibility of injurious effects of a nonvisible nature (such as an effect upon reproductive ability or growth rates) is being explored. The residual effects of steady DC voltage gradients of sufficient intensity to produce narcosis and tetanus in rainbow trout were studied by Kynard (1975). No significant effects of narcosis (induced at 250 mV/cm) on the growth rates and normal photonegative behavior of the trout were noted. Maxfield, et al. (1971) examined the residual effects of pulsed DC shocking on the survival, growth and fecundity of rainbow trout. Two year classes, the young of the year and yearlings, were exposed for 30 sec to voltage gradients of 1 V/cm and .75 V/cm, respectively. No effects on survival, growth or fecundity were noted for test organisms, nor were effects on the survival and development of the eggs and fry of exposed fish noted. Schreck, et al. (1976) investigated the short term, nonlethal physiological changes in blood chemistry and cardial respiratory responses in electroshocked rainbow trout and concluded that fish returned to a normal condition within 6 hours post-shock. Use of a 600 V pulsed DC electroshocker (frequency 60/sec, duration 6 msec) for 31 the collection of gravid chinook, coho (Oncorhynchus kisutch) and chum (O. keta) salmon had no effect on the survival of their progeny from the green egg stage to fry. Progeny of electroshocked showed no greater incidence of deformities, nor lesser growth rates (source unknown). Other Aquatic Species The narcotic effects of DC fields on non-salmonid fish were noted during studies conducted at Vastervik, Sweden (Héglund, 1971; S. Smedsfelt, pers. comm.). Fish held within 2 m of the DC anode of the 200A system were unconscious at the instant of current closing, but recovered with current breaking. No effect was noted at distances greater than 2.5 m, and shielding of the anode was recommended for mitigation. No tetanus or mortality was reported for fish. Other planktonic and benthic organisms showed no response to the fields of either electrode. Higman (1956) and Kessler (1956) independently examined the involuntary "hopping" response of the pink shrimp, Penaeus duorarum Burkenroad, in DC electric fields. Anode-facing shrimp elicited a sharp, vertical jump caused by an involuntary contraction of the abdominal muscle in low voltage fields (0.06 to 0.39 V). Threshold voltages for the hopping response were twice as high for shrimp facing the cathode. Voltage gradient was not specified. In an examination on the effects of electrofishing on non-target organisms in freshwater streams, Mesick and Tash (1980) evaluated narcosis in nine species of benthic stream insects exposed to DC fields. Voltages similar to those commonly used in electrofishing induced drift in eight species. Threshold voltages for electronarcosis varied with species, body size, and temperature. Temporary reduction in productivity, due to loss of benthic species, was predicted for areas of frequent or continuous electric field impact. BEHAVIORAL EFFECTS OF ELECTRIC FIELDS Recent investigations into the biological effects of electric fields have identified the tremendous sensitivity of many aquatic species to low voltage gradients. The ability of aquatic organisms to detect field magnitudes which naturally occur in nature suggests that fields produced by other organisms, 32 geoelectric and meteorological events, and oceanographic processes may be used for information and behavioral cues for aquatic organisms. Electrical cues have been implicated in communication within and between species (Hopkins, 1973), detection of predator and prey (Bullock, 1973), postural control (Feng, 1977) and orientation and navigation (Royce, et al., 1968). Orientation and Navigation Considerable attention has been given to the possibility that the migratory orientation of salmon and other fishes in the open ocean may use the earth's magnetic field in a system of bico-ordinate navigation (Royce, et al., 1968; Rommel and McCleave, 1973 a,b). Two of the potential mechanisms for the use of geomagnetic cues in navigation involve sensitive electroreception: (1) orientational information may be determined from electromotive forces produced by the motion of water through the geomagnetic field (Rommel and McCleave, 1973a,b), and (2) the fish's motion through the earth's magnetic field may produce detectable electrical potentials within its own body (Street, 1976; Kalmijn, 1978). Additional information on direct perception of geomagnetic fields is presented in the following section. Water moving horizontally across the vertical component of the earth's magnetic field induces an electromagnetic field transverse to the direction of flow (Harden-Jones, 1968). Induction of electric fields occur in ocean currents, and to a lesser extent, in lotic freshwaters. Voltage gradients up to 0.005 mV/cm | have been measured in major ocean currents (Kalmijn, 1971). In the northern hemisphere, the induced electrical current flows from right (+) to left (-) when facing down-current. Sensitivity to weak electric fields of the magnitude found in major ocean currents exists in widely separated groups of aquatic organisms. Further, the polarity and strength of weak electric fields have been shown to influence orientation in eel elvers (Zimmerman and McCleave, 1975), elasmobranchs (Kalmijn, 1978), catfish (Peters and Van Wijland, 1974) and other marine species. Demonstrated sensitivity levels and positive indications of orientational responses in several aquatic species makes this a potential model for orientation of fishes undertaking a major open ocean migration. However, direct evidence has not been presented for populations of ocean migrating salmonids, which are of particular importance to this review. 33 BIOLOGICAL EFFECTS OF MAGNETIC FIELDS IN_THE MARINE ENVIRONMENT INTRODUCTION It has been proposed by Kholodov (1974) that during the course of evolution, biological systems have become adapted to a definite range of magnetic field intensity, just as they became adapted to regimes of temperature, atmospheric pressure, and so on. Although the literature on biological magnetic field effects is limited, it is evident that many physiological and behavioral characteristics of plants and animals, ranging in complexity from unicellular algae to mammals, are responsive to abrupt increases and decreases in the intensity of the magnetic field. PHYSIOLOGICAL EFFECTS There is little literature available on the physiological effects of low magnetic fields on aquatic, and specifically marine, organisms. Studies which are available generally concentrate on growth, reproduction and mortality effects of low magnetic fields; neither the anatomical subcellular or organ level of function has been studied. Halpern (1966) exposed cultures of the simple algae Euglena and Chlorella to magnetic field intensities ranging from 0.001 to 1000 gauss (G) for one to three weeks. The reproduction rate of both species was accelerated at the lower field intensities, and inhibited in higher fields. The influence of magnetic fields on the larvae of the American oyster, Crassostrea virginica, at the period of their setting was examined by Hartman and Claus (1971). Horizontal and vertical fields of two field strengths (35 and 58 G) were employed for 2-4 days of exposure. Horizontal Magnetic fields of 58 G resulted in 100 percent larval mortality for 3-4 days exposure; vertical fields led to 93 percent mortality for 3-4 days exposure. Shorter exposures to the vertical 58 G field had no effect. The 34 horizontal 35 G magnetic field resulted in 100 percent larval mortality after 4 days of exposure, but was without effect at shorter exposures. The 35 G vertical field resulted in 20 percent mortality with a simultaneous doubling of sets at 4 days exposure, and increased the number of sets but caused no mortality at shorter exposure times. The biological mechanism for these influences are unknown. The reproductive success of other aquatic organisms may also be effected by Magnetic fields. Several generations of the guppy Lebistes reticulatus were subjected to exposures of a 500 G magnetic field by Brewer (1979). Brood size was normal in the first generation but the gestation period was reduced by 30%. The second generation had an average spawn rate reduction of 50 percent and reduction of the gestation period by 30 percent. Reproduction was entirely inhibited for the third generation of guppies in the magnetic field. McCleave, et al. (1974) examined the effect of a magnetic field with a flux density equal ito that of the geomagnetic field (0.5 G) on activity levels and diel patterns of American eels (Anguilla rostrata) and Atlantic salmon (Salmo salar). Neither species demonstrated sensitivity to the 0.5 G field, and no affect of alternating 24 hour periods of exposure and non-exposure on activity were noted. Activity rhythms were not synchronized by 1 hour of magnetic field exposures every 23 hours. A replication of this study by Richardson, et al. (1976) confirmed these results. An increase in the activity level of stickleback was elicited in a much greater magnetic field during an experiment conducted by Kholodov (1958). Activity increased by 64 percent in a magnetic field strength of 50 to 150 G. Duration of exposure is unknown for this study. EFFECTS ON ORIENTATION AND NAVIGATION Theories of magnetic field perception by animals, initially viewed with skepticism, have recently been implicated as a means of orientation and navigation in migrant animals which can respond to earth-strength fields. Yet even more fundamental than the use of geomagnetism as a migration cue, 35 modern studies indicate the geomagnetic field influences orientation in simpler organisms which do not migrate. The deep-seated nature of responsiveness to magnetism in biological organisms became apparent with the discovery of magnetic responsiveness in Volvox aureus, a unicellular alga which is directly descended from one of the earliest forms of life. The turning response of Volvox in a weak magnetic field was documented by Palmer (1963) for two 5.0 G horizontal fields, one parallel and the other perpendicular to the horizontal geomagnetic field. Clockwise turning of the alga increased by 43 and 150 percent, respectively, for the two experimental conditions. Volvox was shown to be able to perceive Magnetism and distinguish between intensities and directions of magnetic force. A second simple life form, identified as Blakemore's mud bacteria, moves in response to weak magnetic fields of the magnitude of the geomagnetic field (0.5 G) (Blakemore, 1975). When separated from the substrate, the bacteria swim back to the seafloor following the earth's magnetic field lines (Kalmijn and Blakemore, 1978). Their response is believed to be related to the presence of ferromagnetic particles within the cytoplasm membrane. Brown (1962) presents evidence that the planarian (flatworm) Dugesia and the protozoan Paramecium respond to weak magnetic fields (0.17-10.0 G). Dugesia altered its orientation in response to fields both parallel and perpendicular to its body, and was able to resolve intermediate angular orientations of the field with precision. The orientation of mud-snails (Nassarius obsoleta) is also cued from the earth's magnetic field. The orientation of snails in 0.17 to 1.5 G fields parallel and perpendicular to the earth's geomagnetic field was compared to control snails over a two-month period (Brown, et al., 1960). The mean paths of snails in the higher experimental fields were significantly to the left of the control paths. In subsequent studies, Brown, et al. (1964) exposed snails to abrupt reversals of the horizontal component of the geomagnetic field. The maximum alteration of normal snail orientation occurred when the strength of the reversed field was closest in strength to the earth's natural horizontal field (0.17 G). 36 The electroreceptive abilities of an elasmobranch fish (see previous section) allows it to indirectly detect magnetic orientation by sensing the electric field induced by the movement of seawater or its own body through the geomagnetic field. Brown and Il'inskii (1978a, b) studied the response of the ampullae of Lorenzini (the elasmobranch electroreceptor) in Black Sea skates (Raja clavata and Trygon pastinaca) to changes in the vertical component of the magnetic field. The nature of responses to magnetic fields depended on induced electrical currents in the animal's body and in the surrounding seawater. Skates were shown to be able to detect fields as low as the vertical component of the geomagnetic field (0.35 G). Knudtson and Stimers (1977) examined the sensitivity of three other elasmobranch species (Cephalloscyllium ventriosum, Heterodontus franscisci and Urolophus halleri) to magnetic fields of varying magnitude and direction. H. francisci displayed an electroreceptor-mediated response, while Cc. ventriosum seemed to experience direct stimulation of nerves and muscles by, the magnetic field. U. halleri oriented along a Magnetic axis, but the method of field detection was unclear. Magnetic field strengths that elicited responses were greater than the earth's magnetic field strength. The possibility that migrant eel (Anguilla sp.) directly or indirectly utilize magnetic cues in navigation has been investigated by Tesch (1974), McCleave, et al. (1971) and McCleave and Power (1974). Experiments by Tesch (1974) with elvers and subadults of the European eel (A. anguilla) seem to indicate they are able to determine compass direction directly from magnetic field forces. However, American eel (A. rostrata) showed no orientational response when exposed to different magnetic fields (0.54 G, <0.02 G, 2.00 G and 0.52 G in the reversed direction) (McCleave and Power, 1974). Nevertheless, American eel may indirectly utilize magnetic cues for orientation by detecting the electric fields induced by the movement of seawater through the geomagnetic field. The theory of orientational response to magnetic cues has recently been extended to the open water migrations of salmon. Experimental studies have - demonstrated that salmon exhibit directional preferences, influenced by a variety of sensory mechanisms, during open water movements. Quinn (1980) 37 documented the directional preferences of sockeye salmon (Oncorhynchus nerka) fry in laboratory conditions simulating migrations within an inland lake. Directional preferences were maintained under both overcast and clear skies, and under plastic covers. A 90° shift in the earth's magnetic field caused a 90° change in the mean direction of movement of fry at night and in covered tanks. A shift in the magnetic field had no effect on orientation in fish with a view of the day-sky, indicating celestial cues may also be operative. Based on the indication that juvenile sockeye's directional preferences are determined in part by magnetic fields, Quinn (198la) compared the Magnetosensory system of salmon with those of other organisms. Unlike birds, salmon fry did not reverse their compass orientation 180° when the magnetic field's vertical component was inverted, but rather displayed northerly (31°) orientation similar to that of fry in two different control conditions (325° and 22°). A search for some type of magnetized material (implicated as possible magnetic transducers in the magnetic sensory systems of bacteria, honeybees and homing pigeons) was not found in sockeye salmon fry. The mechanism of magnetic detection in salmon remains unknown. Quinn (1981b) has developed a theory for the open ocean navigation of salmon based on their apparent use of magnetic cues in determining directional preferences. The model proposes that homeward migrating Pacific salmon use an active orientation system involving a map-compass-calendar system of navigation. A bi-coordinate grid of the earth's magnetic inclination and declination isolines constitutes the map; compass mechanisms previously documented in juvenile salmon include celestial and magnetic orientation, and are proposed to maintain the headings determined from the map sense. An assessment of daylength or the rate of change in daylength (tied to a latitude sense) combines with endogenous circannual rhythms to provide a calendar sense. The range of inclinations, declinations and daylengths in the regions occupied by Pacific and Atlantic salmon are presented. At present, this model is theoretical. However, three types of experiments, designed to test the map hypothesis, are proposed. 38 The coupling of magnetic cues with other sensory information may also be used in navigation by some species of marine mammals. In experiments with harbor seals (Phoca vitulina), James and Dykes (1978) and James and Rynoff (1972) discovered that seals, captured on Sable Island and released in places from which the sea was not visible, headed SSW on the shortest route to the coast. Based on a complex series of experiments, the authors hypothesized seal navigation involved detection of the earth's magnetic meridian, as well as use of polarized light and audiovisual cues. 89 BIOLOGICAL EFFECTS OF MARINE CHLORINATION INTRODUCTION The application of chlorine to natural waters for industrial, biocidal and disinfection purposes has been a common practice for over 175 years. Although the chemistry and biological effects of chlorine in freshwater environments is relatively well known, only recently has the complicated chemistry of chlorine in seawater and effects on marine organisms and ecological communities been reported in the literature. This review summarizes major recent literature reporting laboratory and field observations of effects of chlorine applications to marine waters. Emphasis has been placed on reporting concentration criteria for sublethal and lethal (acute) toxic effects to marine and estuarine organisms. Additional literature reviews of marine and/or freshwater chlorination are presented by Brung (1976), Davis and Middaugh (1976), and Mattice and Zittel (1976). AQUATIC LIFE CRITERIA FOR CHLORINE The water quality criteria for total residual chlorine (TRC) established by the U.S. Environmental Protection Agency (U.S. EPA, 1976) are .002 mg/1 for salmonids and 0.010 mg/l for other freshwater and marine organisms. A recent critique of EPA criteria (DeGraeve, et al., 1975) indicates the distinction between salmonids and other aquatic organisms may not be warranted in view of 96-hour bioassay results showing that some organisms (particularly freshwater species) are more sensitive to TRC than are salmonids (Ward and DeGraeve, 1978). Other studies have indicated the 10 mg/l criteria may not be sufficient to protect some marine organisms (Bellanca and Bailey, 1977). DeGraeve, et al. (1979) suggest the criterion for marine chlorine applications be established for "oxidant species," which result from chlorine reaction with P naturally occurring inorganic elements in seawater, rather than for residual 40 chlorine (see following section). Mattice and Zittel (1976) suggested a "chronic toxicity threshold" of 0.020 mg/l of oxidant species for marine waters. However, sublethal effects can occur at lower oxidant levels for adult marine organisms (Geoffrey and Middaugh, 1978), and eggs and larvae may be even more susceptible to sublethal and lethal effects (Roberts, et al., 1979). DEGRADATION OF CHLORINE IN SEAWATER The chemical reaction of chlorine with naturally occurring inorganic and organic elements in seawater produces oxidant species and chloro-organics which may be directly toxic to marine organisms. A theoretical model summarizing the suspected pathways of chlorine degradation in seawater is presented in Figure A-l. Rates, coefficients and physical-chemical factors which control reaction and end products are obviously omitted. The persistence, bioaccumulation, transport and fate of chlorine-induced oxidant species have only recently become topics of investigation. The level I to level II reaction represents the hydrolysis of chlorine gas to hypochlorous acid, hypochlorite ions and sodium hypochlorite. This reaction goes to completion within seconds of chlorine addition. The abundance and chemical composition of oxidant species resulting from the level II to level III reaction is determined by seawater characteristics, including temperature, pH, ammonia concentration, ultraviolet light, salinity and bromine availability. Formation of the oxidant chloramine from an ammonia- chlorine reaction is expected, however reactions with bromide to form bromine (and other oxidants) is the principal reaction (Carpenter and Macalady, 1976). The further decomposition of bromine to bromamine is facilitated by high salinity. The presence of these oxidants in effluent may be more toxic than chlorine residuals to several aquatic species, including salmonids (Ward and DeGraeve, 1980). Level III to level IV represents the reaction of oxidant species with naturally occurring organics in seawater (Jolley, 1973). The stable and products indicated in level V occur through a variety of chemical reactions occurring in levels I through IV. 41 rT LE IV Figure A-l. Chlorine gas (C1,) Hypochlorous acid (HOC1) Hypochlorite ions (0C17) Sodium Hypochlorite ~ (Na0C1) Chlorine-induced Oxidants Halogenated Organics Cl, Br Degradation processes of chlorine in seawater (from Davis and Middaugh, 1976). 42 CHLORINE TOXICITY TO MARINE PLANKTON Effects of chlorination and thermal pollution on plankton viability have been investigated in some detail due to entrainment of these organisms in chlorinated power plant cooling water systems. Carpenter, et al. (1972) observed an 83% decline in productivity of phytoplankton cultured in cooling waters from a nuclear generating plant, with intake TRC levels of 1.20 mg/1 and a chlorine-induced oxidant (CIO) residual of 0.04 mg/1 measured at discharge. Gentile, et al. (1976) observed 55% decrease in ATP content of marine phyto- plankton exposed to 0.32 mg/1 TRC for 2 minutes and a 77% decrease after 45 minutes of exposure to TRC concentrations as low as 0.01 mg/l. Relative toxicities of chlorinated and chloro-brominated (an oxidant species) seawater on selected estuarine plankton were investigated by Liden, et al. (1980). Bromine chloride (BrCl) and chlorine (c1,) residuals apparently had similar toxic effects to the organisms tested. Increases in oxygen evolution, carbon- fixation and respiration rates of phytoplankton were recorded following both treatments. Survival was reduced for the zooplankter Acartia tonsa exposed to BrCl and cl, residuals ( 0.10 mg/1) for 24 hours. In additional studies of effects of chlorine and oxidant species on marine zooplankton, TRC concentrations between 250 and 750 mg/l reduced the motility ratio of selected estuarine zooplankton by less than 50 percent (Davies and Jensen, 1975). McClean (1975) documented 90% mortality for the copepod, Acartia tonsa, in 2.5 mg/l residual chlorine for 5 minutes of exposure. The 48-hour LC. for A. tonsa in seawater was found to be less than 0.05 mg/1 TRC (Roberts, et al., 1975). CHLORINE TOXICITY TO BENTHIC ORGANISMS The effects of intermittent or continuous chlorination on marine benthic invertebrates are less well understood than effects on fish. However, studies have been conducted in conjunction with evaluating entrainment effects in power 43 generating stations, and low level chlorination has been extensively used as an anti-foulant. Several invertebrate estuarine species were exposed to various residual chlorine concentrations by Roberts, et al. (1975) under continuous-flow, continuous- exposure conditions for up to 96 hours. Larvae of the clam, Mercenaria mercenaria, and oyster, Crassostrea virginica, demonstrated 48-hour LC.o values of less than 0.005 mg/1 TRC. The 96-hour LC.G of the grass shrimp, Palaemonetes pugio, was 22 mg/1 TRC. The authors assumed only free chlorine was present in all experiments, and did not attempt to measure oxidant species. In subsequent studies, Roberts, et al. (1978, 1979) examined effects of bromine chloride (BrCl) and other chlorine-induced oxidants (CIO) on invertebrates held in continuous-flow systems. The most sensitive species were oysters (Crassostrea virginica larvae and juveniles) with 48-hour LC. of 0.10-0.21 mg/1 50 of 0.10 mg/1 C10. The grass of 0.70 mg/l BrCl. In comparing BrCl, and decapod crustacean zoae with 96-hour LC shrimp was most tolerant with a 96-hour LC. previous experimental work with this series of experiments, the authors concluded bromine chloride is 2-4 times less toxic than Cl, for the invertebrate 2 species tested. Relative toxicities of BrCl and cl, were also compared for selected estuarine food chain organisms (Liden, et al., 1980). Bromine chloride and chlorine residuals apparently had similar toxicities to estuarine invertebrates. Juvenile American oysters and brackish water clams (Rangia cumeata) had no mortalities attributable to Brcl or cl, after 15 days of exposure. Lethal and sublethal effects of chlorination on adult American oysters were observed during chronic exposure on a seasonal basis (Geoffrey and Middaugh, 1978). Chronic exposure to chlorine-induced oxidants produced mortality at high concentrations and severe sublethal effects at lower levels. Sublethal effects included reduced feeding, reduced tissue formation and gonad size, and avoidance of chlorine. Reduced pumping (feeding) has also been noted in oysters - exposed to 0.01 to 0.05 mg/1 residual chlorine (Galtsoff, 1946). 44 Waugh (1964) observed no significant mortality of oyster larvae, Ostrea edulis, exposed to 5.0 mg/1 chlorine for 3 minutes at ambient temperature. However, a chlorine concentration of 0.5 mg/l caused heavy mortality and reduced growth rates of survivors for the barnacle nauplii, Eliminius modestus. Barnacle larvae of the species, Balanus sp., also suffered heavy mortality (80%) after 5 minutes exposure to 2.5 mg/l residual chlorination at ambient temperatures (McLean, 1973). Stage 1 larvae of the American lobster (Homarus americanus) were exposed by Capuzzo, et al. (1976) to chloramines (oxidant species) and free chlorine in filtered seawater (organics removed). Applied chloramine was more toxic than 50 values of 2.02 mg/l and 16.3 mg/1, respectively. Reduced respiration rates were noted at 0.05 mg/1 free chlorine to the lobster, with 48-hour LC chloramine-and 0.10 mg/1 free chlorine. James (1967) observed that residual chlorine concentrations of 0.02 to 0.05 mg/1 caused detachment and passive movement of mussels. Holmes (1970) also demonstrated significant decline in attached mussels at 0.50 mg/1 chlorine. Species of estuarine invertebrates subject to entrainment in the cooling water system of a steam electric station were exposed experimentally to estuarine water with 2.5 mg/l TRC (McLean, 1973). Two amphipods (Gammarus sp. and Melita nitida) and grass shrimp exhibited greater tolerance to chlorine stress than barnacle nauplii and copepods when exposures were limited to 5 minutes. However, when exposures were extended to 3 hours, mortality of amphipods and shrimp reached 25 percent, and within 96 hours after exposure, delayed mortality 59 Of 1.85 mg/1 TRC for Gammarus daiberi. However, the amphipod Crangonyx sp. and isopods claimed nearly 100 percent. O'Connor (1978) found a 1-hour LC showed no response to chloramine concentrations as low as .001 to 0.114 mg/1 (Carlson, 1976). Gibson, et al. (1975) examined synergistic effects of chlorine, copper and thermal maxima for coonstripe shrimp, Pandalus danae. Shrimp were least resistant to residual chlorine concentrations when acclimated and exposed at higher test temperatures (20° C), with 96-hour LC.) values of .110 to .190 mg/l. Reduced growth was observed in shrimp exposed to .080 mg/1 for one month. 45 Roesijadi, et al. (1979) examined the effects of chlorinated seawater on magnesium regulation in the crab Cancer productus. Regulation of haemolymph solution and Mg concentrations was essentially abolished at chlorination levels approaching the 96-hour LC A four-fold increase in ammonia excretion was noted at 0.68 mg/1 TRC. 50° McLean (1972) exposed colonies of the hydroid Bimeria franciscana to various concentrations of chlorine (0.1 to 4.5 mg/1) for 1 to 3 hours and then returned the colonies to their natural habitat. The percentage of new growth was slightly lower in colonies exposed to concentrations of 2.5 to 3.5 mg/l than in controls. CHLORINE TOXICITY TO FISH Larval stages of plaice (Pleuronectes platessa) and Dover sole (Solea solea) were exposed to residual chlorination in seawater by Alderson (1974). Early larval stages of both fish species had 48 to 96-hour LC.. values between 25 50 and 71 mg/l. No attempt was made to differentiate between effects of chlorine and bromine compounds produced as a result of seawater chlorination. Several estuarine fish species previously used for tests of cl, toxicity were tested for toxicity of bromine chloride (BrCl) in a continuous-flow seawater system (Roberts and Gleeson, 1978). Atlantic silverside (Menidia menidia), Atlantic menhaden (Brevoortia tyrannus) and spot (Leiostomus xanthurus) all had a 96-hour LC. of 0.21-0.23 mg/l BrCl. The effects of bromine chloride and chlorine residuals on menhaden and spot were found to be similar in tests conducted by Liden, et al. (1980). In more recent tests with juvenile spot, Middaugh, et al. (1980) examined lethal and sublethal effects of chlorine produced oxidants in continuous flow tests at 26-31 ppt salinity. Spot were exposed to two sublethal concentrations of oxidants (0.09 and 0.12 mg/1) and three acutely toxic levels (0.13, 0.20 and 0.37 mg/1). Opercular ventilation rates were higher in exposed fish than in controls, returning to near normal in sublethal exposures but remaining elevated until death in lethal exposures. Blood pH and oxygen uptake declined after 48-hour exposure in all concentrations. Damage to circulatory and gill tissues 46 was noted in fish exposed to the highest concentration of 0.37 mg/l. For these estuarine fish, and other species, the combined effects of chlorine and temperature indicates that thermal shock increases the toxicity of chlorine (Hoss, et al., 1977). The effects of temperature in enhancing toxic effects of chlorinated water to marine animals may be due to an interaction of uptake rates and regulation of physiological rates, and the greatest enhancement in sensitivity could be expected at the upper end of a species’ thermal tolerance (Capuzzo, 1978). Stober and Hanson (1974) examined synergistic effects of chlorine and thermal stress to pink salmon, Oncorhynchus gorbuscha, and chinook salmon, 0. tshwaytscha. After a 24-hour recovery period, LC.) values for both species were 0.50 mg/1 for 7.5 minute exposure and 0.25 mg/l for 15, 30 and 60 minute exposures. Sensitivity increased with increasing temperature and duration of exposure. During a 2-hour exposure to fluctuating residual chlorine levels, juvenile pink salmon demonstrated more sensitive LC. 5 of 0.045 mg/l. Stober, et al. (1978) reported on short-term and 96-hour static and continuous- flow seawater bioassays with shiner perch, Cymatogaster aggregata, and coho salmon, Onchorhynchus kisutch. Short-term flow-through tests indicated coho salmon are more sensitive to chlorinated seawater than shiner perch. Both species were more sensitive to total residual oxidant levels (TRO) when a 7° C thermal shock was also applied. Shiner perch sensitivity seemed to vary with life stage and size. Fluctuations of chlorine in the bioassays prevented estimations of 96-hour LC. values for these tests. In behavioral studies, coho salmon avoided all concentrations of chlorine above 0.002 mg/1 TRO in ambient seawater. Shiner perch did not respond with an avoidance or attraction effect to chlorine levels less than .175 mg/1 TRO. In more recent studies, Stober, et al. (1980) established LC. values for coho salmon smolts and 1 to 3 month old shiner perch under chlorine and thermal stress conditions. The mean 60-minute LC.. value for shiner perch ranged from .23 mg/1 50 at 20° C to .31 mg/l at 13° C. Coho salmon 60-minute LC. values were .13 mg/1 at 20° C and .21 mg/l at 13° C. The LC.9 values for coho salmon in chlorinated seawater averaged 55% of those for shiner perch. A significant avoidance effect 47 for coho salmon occurred at .002 mg/1 TRO and was enhanced with increasing temperature. Perch avoidance occurred at .175 mg/1 TRO, however, a significant preference occurred at 16° C and 20° C with TRO concentrations of .010, .025, -050 and .100 mg/l. The attraction of shiner perch to sublethal chlorine levels in seawater has also been documented by Dinnel, et al. (1979). The behavioral effects of residual chlorination on several estuarine fish species were studied in flowing-water bioassays by Meldrim, et al. (1974) and Meldrim and Fava (1977). White perch, Morone americana, consistently avoided chlorine levels as low as 0.08 mg/1 TRC at temperatures of 7 to 17° C. Atlantic silversides also avoided 0.08 mg/l TRC at temperatures from 8 to 28° C, but preferred this residual concentration when fish acclimated to 7° C were exposed at 12° C. Mummichogs, Fundulus heterochitus, and hog chokers, Trinectes maculatus, avoided residual chlorination levels as low as 0.03 mg/l. An additional behavioral effect which could occur with fish and other marine organisms may be the interruption of chemical communication and pheromone systems in chlorinated seawater (Jolley, et al., 1976). The combination of products of chlorine degradation with organic constituents in seawater may interfere with behaviors which depend upon natural organic chemicals, such as the use of olfactory imprinting and sensing during migration in homing fish. BIBLIOGRAPHY ELECTRIC FIELDS Agalides, E., 1967. Sensitivity and Behavioral Reaction of Sharks to Electric Stimuli. General Dynamics/Electronics, New York, Final Report, 83 pp. Lemon sharks (Negaprion brevirostris) were studied to determine their sensitivity to electric stimuli. The Lorenzini ampulla, a skin sensory receptor found in elasmobranch fishes, can sense temperature variations, water displacement or electric stimuli. Sensitivities to electric currents between 0.65 and .00024 amperes per ampulla were determined. Altmann, G., 1969. The Physiological Effect of Electrical Fields on Organisms. Arch. Met. Geoph. Biokl., 17:269. Direct and alternating current electric fields act on physiological processes and the behavior of organisms. Artificial fields of static direct and alternating current were tested on various animals, and an increase in activity in static fields of continuous current as well as in intermittent fields of direct current and fields of alternating current with 10 cps could be clearly observed. A rise in the oxygen consumption parallel to the increase in activity was also measured. Animals subjected to electric currents in water show the same phenomenon. The direction of the current through the body is important. An activation of the matabolism was evident in the rise of the free amino- acids in the tissues, which would seem to prove that electro-magnetic energies interfere with the chemistry of the metabolic process of the tissue and the cells. Applegate,. V.C., P.T., Macy and V.E. Harris, 1954. Selected Bibliography on the Applications of Electricity in Fishery Science. U.S. Fish and Wildlife Service, Special Scientific Report: Fisheries No. 127, 55 pp. Balaev, L.A. and N.N. Fursa, 1980. Behavior of Ecologically Different Fishes in Electric Fields. Vopr Ikhtiol, 20(4):751-755. Bary, B.McK., 1956. The Effect of Electric Fields on Marine Fishes. Marine Res. No. 1, Her Majesty's Stationary Office, 32 pp. Bodznick, D. and R.G. Northcutt, 1981. Electroreception in Lampreys (Lampetra tridentata) Evidence that the Earliest Vertebrates were Electroreceptive. Science, 212(4493) : 465-467. 49 Evoked potential and unit responses from the lamprey brain to weak electric fields demonstrate that lampreys have an electrosensory system as sensitive as those of other electroreceptive fishes. Brown, F.A., 1962. Response of the Planarian, Dugesia, to Weak Horizontal Electrical Fields. Biological Bulletin, 123:282-294. Effects of horizontal electrostatic-field gradients on the freshwater planarian, Dugesia dorotocephala, were determined by comparing paths chosen in field gradients modified by aluminum plates in freshwater. Time of day, original magnetic compass direction of enforced orientation of the worm, and natural magnetic field were also altered. The planarian was able to perceive a change of 2 V/cm in air, equivalent to detection of fractions of a microvolt/cm gradient in the freshwater experimental environment. The strength and character of worm response to a right-angle potential change was related to the direction the worm was oriented in the earth's magnetic field, and to time of day. Dugesia was also able to distinguish the direction of a gradient across its body. Ability to resolve small differences in strength and direction of electrostatic fields can contribute as a navigational aid. Bullock, T.H., 1973. Seeing the World Through a New Sense: Electroreception in Fish. Am. Sci., 61:316. Many species of fish have developed the ability to receive electrical signals useful for detecting prey or predators, possibly useful in sensing changes in water salinity, ocean or river currents, and geomagnetic or geoelectric events. In addition, many other species are both electroactive and electroreceptive, enabling communication for the purposes of remote identification of animate and inanimate objects, which is useful in seeking food and mates or in avoiding enemies. Fish have also been demonstrated to be sensitive to atmospheric electricity, for example due to thunderstorms, and might be able to sense man-made fields such as result from current return paths in the ground. Burrows, R.E., 1957. Diversion of Adult Salmon by an Electrical Field. U.S. Fish and Wildlife Service, Special Scientific Report No. 246, 11 pp. An alternating current electrical weir consisting of a line of hanging electrodes and a submerged ground line (110 V, single phase, (d) cycle) was used to divert adult chinook and sockeye salmon. Effective voltage gradients varied from 0.3 to 0.7 V/in (118 to 275 mV/cm) in freshwater. No deleterious effects of electrical diversion either on survival until maturation of adult salmon or on egg viability and resulting progeny were noted. Collins, G.B., C.D. Volz and P.S. Trefethen, 1956. Mortality of Salmon - Fingerlings Exposed to Pulsating Direct Currents. Fish. Bull. No. 92:61-81. The influence of voltage gradient, current density, pulse frequency, and duration of exposure upon the mortality of chinook salmon fingerlings, 50 Oncorhynchus tshawytscha, exposed to pulsating direct current was examined experimentally in relation to the length of the fish, water temperature and pulse duration. A square-wave form current was used and the following ranges explored: voltage gradient 0.5 to 10 V/cm, pulse frequency 2 to 15 sec, duration 20 to 80 msec, current density 0.05 to 1.9 mamp/cm2, duration of exposure 0.5 to 20 min, fingerling lengths 4 to 12 cm and water temperature 10° to 25°C. Mortality increased in a constant ratio with voltage gradient, an increase in current density, or both. However, the total voltage to which the fish was exposed (fish length x voltage gradient) was the effective factor in mortality. Mortality increased with pulse frequency and with duration of exposure. Mortality also increased with increasing water temperature. In tests examining combined effects of voltage gradient and current density, mortality of fingerlings did not occur below a threshold level of 4 V/cm voltage gradient and 0.19 mamp/cm2 current density (g= 21,000 ohm-cm). The possibility of sublethal deleterious effects was not explored in this study. Denzer, H.W., 1956. Die Electrofischeri. Handb. Binnenfisch. Mitteleurop., 5:142-233. Dijkgraaf, S., 1962. The Functioning and Significance of the Lateral-Line Organs. Biol. Rev., 38:51-105. Enger, P.S., L. Kristensen and 0. Sand, 1976. The Perception of Weak Electric D.C. Currents by the European Eel (Anguilla anguilla). Comp. Biochem. Physiol., 54A:101-103. Eels were conditioned to exhibit cardiac deceleration to direct current electric fields. Current density thresholds averaged 0.08 «A/cm? (lowest value 0.04 «A/cm?) in freshwater of resistivity 3 x 104 ohm-cm and increased with decreasing water resistivity (increasing salinity) to 9.5 4 A/cm? at 75 ohm-cm. Thresholds were 2-3 times higher for a current direction perpendicular than parallel to the fish's body. Calculated voltage gradients were 0.4-0.6 mV/cm. These voltage thresholds were at least 1000 times higher than those demonstrated for the American eel by Rommel and McCleave (1972). Erkkila, L.F., B.R. Smith and A.L. McLain, 1956. Sea Lamprey Control in the Great Lakes. U.S. Dept. Int. Special Scientific Report, Fisheries No. 175. Feng, A.S., 1977. The Role of the Electro Sensory System in Postural Control of the Weakly Electric Fish Eigenmannia virescens. J. Neurobiol, 8(5): 429-438. The role of the electrosensory inputs in postural control was examined in the weakly electric fish E. virescens. These fish exhibited tonic postural tile in response to a tilted plexiglas substrate in both transverse and longitudinal planes (rolling and head-up pitching responses, respectively), but not to an electrically transparent agar Di substrate. The fish's pitching and rolling responses were abolished when the electrosensory inputs from the trunk were bilaterally eliminated even though the fish's visual and mechanosensory lateral-line systems remained intact. A unilateral lesion abolished the rolling response but not the pitching response. These results demonstrated the functional role of the electrosensory system in postural control. In addition to its known role in social communication and in object location, and the underlying neuronal mechanism was discussed. Flux, J.E.C., 1967. Factors Affecting the Response of Trout to an Electric Field in Fresh and Salt Water. Jour. Fisheries Res. Bd. Can., 24:191-199. Groody, T., A. Loukashkin and N. Grant, 1952. A Preliminary Report on the Behavior of the Pacific Sardine (Sardinops caerula) in an Electrical Field. Proc. Cal. Acad. Sci., 27:311-323. A direct relation between current density and mortality that depends on fish size and duration of exposure was demonstrated for Pacific sardine; the relation was found to be "especially true when nonpulsating (direct) current was used." Halsband, E., 1967. Basic Principles of Electric Fishing. In: Fishing With Electricity, Vibert (ed.), European Inland Fisheries Advisory Commission, Fishing News (Books) Ltd., pp. 57-64. General reactions of fish to direct current exposure are outlined in a discussion of electric fishing principles. Basic principles include the following: (1) Response threshold values of current density are reproducible for fish of the same species and size. (2) Threshold values diminish as the size of fish increases due to the greater head-tail body voltage intercepted by larger fish. (3) In media which are more conductive than the body of the fish, reaction thresholds occur at lower potential gradients than in "equivalent media." (4) Direct current exposure has less neurophysiological effect than alternating currents and interrupted currents. However, DC has greater residual effects on general metabolism. Harden-Jones, F.R., 1968. Fish Migration. St. Martin's Press, New York, pp. 195-196. Mechanisms of orientation using electrical cues were summarized and comparisons to known levels of sensitivity were made. Water moving horizontally across the vertical component of the earth's magnetic field induces an electromagnetic field (emf) transverse to the direction of flow. The field corresponding to a flow of 1 kt (50 cm/sec) with a vertical magnetic field component of 0.4 gauss is on the order of 0.2 = y~V/cm; which is within the demonstrated detectibility for Gymnarchus “Oo. 15 pV/cm) and the elasmobranch ampullae of Lorenzini (0.01 ,V/cm). In the northern hemisphere, the electrical current flows from right (+) to left (-) when facing downstream, and left to right upstream. The maximum emf is detectible by lying along the axis of the water current for fish with sensitive bilateral electroreceptors. 52 Haskell, D.C., J. MacDougal and D. Geduldig, 1954. Reactions and Motion of Fish in a Direct Current Electric Field. New York Fish and Game Journal, 1(1) :47-64. A study was undertaken of the reactions of fish subjected to continuous and pulsed direct current. It was found that migration of fish to the positive electrode in the DC shocker is an involuntary response resulting from shock to the nerve endings in the muscles. Steady DC modifies normal swimming motion and guides the fish toward the positive pole. Intermittent DC causes an involuntary motion consisting of a turn toward the anode and forward motion at each circuit closure. The intermittent effect requires a lower voltage than that of steady current. Hauck, F.R., 1949. Some Harmful Effects of the Electric Shocker on Large Rainbow Trout. Trans. Am. Fish. Soc., 77(1947):61-64. Higman, J.B., 1956. The Behavior of Pink Ground Shrimp Penaeus duorarum, Burkenroad, in a Direct Current Electrical Field. Fla. St. Bd. Conserv. Tech. Ser. No. 16:1-23. Pink shrimp were shown to exhibit a "scare hop" reaction for each pulse of DC electricity at low power levels. Hopping consisted of a sharp vertical jump caused by an involuntary contraction of the shrimp's abdominal muscle. It is not known whether this reaction is caused by stimulation of the central nervous system or by direct stimulation of the shrimp's abdominal muscle. However, the response does occur at low power levels and may cause the shrimp to leave their burrows. Héglund, H., 1971. Research with Electricity at Vaestervik. Lysekil (105) :1-16. The effect of DC fields on fish and other organisms was studied in 1949 in a bay in the Vastervik area of Sweden. Electrodes were placed in seawater 20-25 m deep, and were 900 m apart. Current strength was 380/220 V; experiment duration was one month. Salinity, temperature, DO and pH showed only minimal changes. No adverse effects were noted on plankton, pelagic or benthic fauna, except in immediate vicinity of electrodes where fish appeared stunned or in state of shock. Suggested shielding at 20 m to avoid fish contact with direct effect of current and gases and iron hydroxide formed during electrolysis. Holmes, H.B., 1948. History, Development and Problems of Electric Fish Screens. U.S. Fish and Wildlife Service, Special Scientific Report No. 53, 62 pp. Holzer, W., 1932. Uber Eine Absolute Reizspannung Bei Fischen. Pfliigers Arch. ges. Physiol., 229:153-72. Hoppe, W., et al., 1977. Electroreception and Orientation in an Electrical Field. Biophysics, Springer-Verlag, Berlin, pp. 601-608. 53 Kalmijn, A.J., 1966. Electro-Perception in Sharks and Rays. Nature, London, 212: 1232-1233. Marine sharks and rays were conditioned to exhibit bradycardia to direct electric currents. Sensitivity thresholds of 0.01 pV/cm were demonstrated in seawater with a resistivity of 25 ohm-cm, corresponding to a current density threshold of 0.4 x 10-3 ,A/cm*, Kalmijn, A.J., 1977. The Electric and Magnetic Sense of Sharks, Skates and Rays. Oceanus, 20(3): 45-52. Five species of elasmobranchs electrically located agar-screened prey. One species, Mustelus canis, exhibited predatory behavior toward two pairs of electrodes, confirming the experimental work. Kalmijn, A.J., 1978. Experimental Evidence of Geomagnetic Orientation in Elasmobranch Fishes. In: Animal Migration, Navigation and Homing; Schmidt-Koenig and Keeton (eds.), Springer-Verlag, Berlin. Marine sharks, skates and rays have an electric sense enabling them to detect direct current voltage gradients as low as 0.01 ,V/cm within the frequency range of up to 8 Hz. The electroreceptor is located in the ampulla of Lorenzini, a sensory structure in the elasmobranch snout. Swimming through the earth's magnetic field, they induce electric fields which may provide electromagnetic compass sense. Electromagnetic orientation has been demonstrated in recent training experiments. Kessler, D.W., 1965. Electrical Threshold Responses of Pink Shrimp Penaeus duorarum Burkenroad. Bulletin of Marine Science, 15(4):885-895. Threshold voltages of DC electricity producing a hopping response in pink shrimp (Penaeus duorarum) were determined by stimulating shrimp with single capacitor discharge pulses varying from 50 to 500 wzsec in length. Mean threshold voltages ranged from 0.06 to 0.39 V for shrimp held parallel to the field. Threshold voltages were twice as high for shrimp facing the cathode as when facing the anode. Shrimp oriented across the field did not elicit the hopping response, but responded variably with single appendage jerks or slight movements at voltages 1.5 to 5 times the anode-facing thresholds. Larger shrimp responded to lower voltages than smaller shrimp. DC pulse width was inversely related to threshold voltages. Shrimp tested at 14° and 36°C had higher mean threshold voltages than those tested at 20° and 28°C, though salinity had no apparent effect on response. Klima, E.F., 1968. Shrimp-Behavior Studies Underlying the Development of the Electric Shrimp-Trawl System. U.S. Fish and Wildlife Service, Fish. Ind. Res., 4:165-181. 54 - Klima, E.F., 1972. Voltage and Pulse Rates for Inducing Electrotaxis in Twelve Coastal Pelagic and Bottom Fishes. J. Fish. Res. Bd. Can., 29: 1605-1614. Laboratory observations on fish reactions to different DC voltages and pulse rates provided information on electrical characteristics needed for inducing electrotaxis in 12 species of coastal pelagic and bottom fishes found in the eastern Gulf of Mexico and tropical Atlantic. Optimal electrical combinations for fish in seawater varied according to species and length, and ranged from 0.15 to 0.30 V/cm at 15-45 pulses/sec with a pulse duration of 1.0 msec. Kynard, B. and E. Lonsdale, 1975. Experimental Study of Galvanonarcosis for Rainbow Trout (Salmo gairdneri) Immobilization. J. Fish. Res. Bd. Can., 32(2):300-302. Experimental galvanonarcosis treatments had no significant effect on growth or photonegative behavior of rainbow trout (Salmo gairdneri) in uninterrupted direct electrical current. Experimental conditions were as follows: voltage gradient 0.25 V/cm, head-tail voltage 3 V, water temperature 13-21°C, and specific conductivity 450 uohm-cm. Lamarque, P., 1967. Electrophysiology of Fish Subject to the Action of an Electric Field. In: Visert (ed.) European Inland Fisheries Advisory Comm., Fishing News (Books) Ltd., pp. 65-92. Sixteen species of freshwater fish were exposed to direct current electric fields, and a theory of neural response was proposed based on approximately 30 identified reactions. Response thresholds, which would be important for electric fishing or electric screens, are emphasized. Lissmann, H.W., and K.E. Machin, 1958. The Mechanism of Object Location in Gymnarchus niloticus and Similar Fish. J. Exp. Biol., 35(2): 451-486. Maxfield, G.H., R.H. Lander and K.L. Liscom, 1971. Survival, Growth and Fecundity of Hatchery-Reared Rainbow Trout after Exposure to Pulsating Direct Current. Trans. Amer. Fish. Soc., 1971, No. 3, pp. 546-552. Unshocked (control) and shocked (test) rainbow trout (Salmo gairdneri) were held through spawning to determine the effects of electrical shock on the survival, growth and fecundity of the young of the year and yearlings, and on the survival of the eggs and fry of exposed fish. Test groups were exposed for 30 sec to two test conditions - the young of the year to a pulse frequency of 8 pulses/sec, a pulse duration of 40 msec and a voltage gradient of 1 V/cm; and the yearlings to a pulse - frequency of 5 pulses/sec, pulse duration of 60 msec and voltage gradient of 0.75 V/cm. The survival, growth and fecundity of the fish apparently were not affected by the electrical shock, nor were the survival and development of their offspring. 55 McCleave, J., 1973. Effect of Electromagnetic Fields Generated by Naval Communications Systems (ELF) on Biological Clocks of Migratory Fishes. Office of Telecommunications Policy. Studies were made on the cardiac deceleration and activity rhythm of Atlantic salmon and American eel at field strengths of 0.06-0.07 V/m at 45 and 75 Hz. No strong evidence was found but slight decelerations were observed in a few cases. The author gives no information as to whether the fishes were immersed in fresh water (resistivity around 100 ohm-m) or salt water with the resistivity of the Atlantic (2 ohm-m). McCleave, J.D., E.H. Albert and N.E. Richardson, 1974. Perception and Effects on Locomotor Activity in American Eels, and Atlantic Salmon of Extremely Low Frequency Electric and Magnetic Fields. Univ. of Maine, Naval Office. Possible effects of the proposed Sanguine communication system on American eels (Anguilla rostrata) and Atlantic salmon (Salmo salar) were investigated in three ways. Conditioned cardiac deceleration techniques demonstrated that both species are marginally sensitive to Sanguine level ELF (60-75 Hz) electric fields (0.007-0.07 V/m) but not to magnetic fields (0.5 gauss). Locomotor activity levels or diel patterns of the fishes were not affected by alternating 24 hr periods of exposure and non-exposure to the ELF electric or magnetic fields. Activity rhythms were not entrained (synchronized) by 1 hr exposures every 23 hr to ELF electric or magnetic fields. It is concluded that while at least these two species can probably perceive Sanguine electromagnetic radiation, their normal behavior is unlikely to be affected by such fields. Higher frequencies will probably result in less effect than lower frequencies. McCleave, J.D. and J.H. Power, 1978. Influence of Weak Electric and Magnetic Fields on Turning Behavior in Elvers of the American Eel Anguilla rostrata. Marine Biology, 46(1):29-34. The turning behavior of elvers of the American eel was studied in an arena in which horizontal electric or vertical magnetic fields could be manipulated. Objectives were (1) to determine if the strength and polarity of a weak DC electric field influenced elver orientation and to determine if any of such influence was due to electric fields cenerated by the elver's own swimming movements. As electric current density increased from 10-2 ,4A/cm2 to 10* A/cm, elvers turned increasingly more toward the anode (in the lower fields tested they turned more toward the cathode). There were no differences in mean turning angles for groups of elvers swimming in four different vertical magnetic fields (0.54 gauss, <0.02 gauss, 2.00 gauss and 0.52 gauss reversed direction), suggesting that elvers were not influenced by internally generated electric fields. However, swimming speeds were such that the generated fields would have been on the order of 10-4 x A/cm? - or less. Elver orientation apparently could be influenced by electric fields of the magnitude generated by major ocean current systems, but probably are not influenced by electric fields generated by their own swimming in a geomagnetic field. 56 McCleave, J.D., S.A. Rommel and C.J. Cathart, 1971. Weak Electric and Magnetic Fields in Fish Orientation. Ann. N.Y. Acad. Sci., 188:270-282. Twenty-six American eels were tested for natural or conditioned cardia deceleration responses to weak electric fields (0.333 x 1074 to 0.167 ace Oj 2 A/cm?) and eighteen Atlantic salmon tested for Se a: deceleration to weak electric fields (0.167 x 10~? » A/cm“) Thirteen eels (Anguilla rostrata) and eigth salmon (Salmo salar) were tested for natural or conditioned cardiac deceleration responses to reversals of the vertical component of the geomagnetic field (0.38 gauss), DC or pulsed fields 5 times the vertical component (1.90 gauss), or pulsed reversals of the horizontal component (0.17 gauss). Four out of five eels and salmon showed significantly lower mean test rates than mean control rates when an electrical field (0. 167 ~xamp/cm * ) was applied perpendicular to the body axis. No response when field applied parallel to body. Neither eels or salmon appeared to respond to the magnetic fields. McLain, A.L. and W.L. Nielsen, 1953. Directing the Movement of Fish with Electricity. U.S. Fish and Wildlife Service, Special Scientific Report: Fisheries No. 93, 24 pp. Laboratory and field tests were conducted to analyze effects of a pulsed direct current electrode system (duty cycle 0.66, pulse rate 3 per sec) in freshwater on white suckers (Catostomus c. commersoni), brook trout (Salvelinus f. fontinalis) and rainbow trout (Salmo gairdneri). In field tests with white suckers (water temperature 75 to 78°F), fish showed positive involuntary and persistent movement toward the anode. Brook trout (in water temperature 36 to 38°F) experienced first discomfort reaction at a voltage gradient of approximately 0.2 V/cm (80 mV/cm), oriented perpendicular to current flow at 0.3 V/cm (120 mv/cm) and moved toward the anode above 0.5 V/cm (200 mV/cm). Authors concluded application of continuous DC would produce a response to polarity but would restrict the ability of the fish to move. In laboratory tests (water resistivity 7620 ohm-cm) with rainbow trout, fish of various body lengths (9 to 24 inches) responded to pulsed DC at voltage gradients less than 1 V/inch (393 mV/cm), with larger fish showing greater sensitivity. In field tests (water temperature 62 to 63°F) with 14-inch rainbow trout, trout which were successfully drawn to the anode by a voltage gradient of 165 mV/cm immediately left when polarity was reversed and swam away from the cathode. Ten rainbow trout released near the weak fringe of the electrical field turned away from the field at low voltage gradients. However, the persistence of upstream (homing) migrants may be sufficient to force them to penetrate into stronger gradients, where biological effects could occur. McMillan, F.0., 1928. Electric Fish Screen. U.S. Department of Commerce, Bulletin U.S. Bur. Fish., 44:97-128. In tests of fish screen designs, a voltage gradient of 0.27 V/inch AC (106 mV/cm) narcotized a 3.1 inch (79 cm) chinook salmon fry (Oncorhynchus tshawytscha) in seawater. Exposure of fingerling to a gradient of 2155) V/in (590 mV/cm) for 1 minute resulted in death. 57 Mesick, C.F. and J.C. Tash, 1980. Effects of Electricity on Some Benthic Stream Insects. Trans. Am. Fish. Soc., 190(4):417-422. Pulsed direct current, square-wave alternating current, alternating current and direct current, at voltages similar to those currently in use for electrofishing, induced drift in 8 of 9 insect species tested. There was an inverse relationship between the propensity of an individual to drift and the minimum level of voltage required to induce drift. Threshold body voltages varied among and within species at different body sizes and at different temperatures. Temporary reductions in productivity with potential loss of species will occur in areas that are electrofished so frequently that rates of insect displacement are greater than rates of insect recolonization. Miyake, I. and W.R. Steiger, 1958. The Response of Tuma and Other Fish to Electrical Stimuli, U.S. Fish and Wildlife Service, Washington, D.C., Special Scientific Report: Fisheries No. 223, 23 pp. Novak, B. and F.W. Bentrup, 1973. Orientation of Fucus Egg Polarity by Electric AC and DC Fields. (Source unknown), 9(3):253-260. Zygotes of the marine brown alga, Fucus serratus, were subjected to the different modes of electric fields. The result of a former study with conductive dc fields was confirmed using electrostatic de fields of 0.3 to 4 V/cm. The zygotes develop the cell polarity axis parallel to the imposed field with the rhizoid pole toward the cathode. The data support the hypothesis of the authors that imposed electric field induce cell polarity via differential shift of the membrane potential rather than transcellular current flow. Pals, N. and A.A.C. Schoenhage, 1979. Marine Electric Fields and Fish Orientation. Jour. Physiology, 75(4): 349-354. Paulini, E., J.P. Pereira and J. Dradoczy, 1968. Migration of Biomphalaria glabrata in an Electric Field of Pulsating Direct Current. Rev. Brasil Malarial Doencas Trop., 20(1/2):133-138. The behavior of Manorbid snails (Biomphalaria glabrata) under the influence of pulsating direct current was investigated in the laboratory. The folowing conditions were maintained: potential 80-90 V; frequency 1-2 Hz; stainless steel electrodes. The mean velocity of migration varied from 0.2 to 1.7 cm/min. The calculated current density was 0.8-1.2 ma/cm?. An increase of the current density caused the snails to retract the body into the shell and sometimes induced bleeding. Muscular contractions at the rhythm of the pulsating current were visible in most of the specimens. Snails of all shell diameters except small ones (less than 2 cm) migrated under the experimental conditions to the negative electrode. 58 Peters, R.C. and F. Van Wijland, 1974. Electro-Orientation in the Passive Electric Catfish, Ictalurus nebulosus Les. J. Comp. Physiol., 92:273-280. For the "passive" (non-transmitting) elegtro-sensitive catfish, a threshold sensitivity value of 0.8 x 10 a A/ cm in water with a specific resistivity of 2.5 x 103 ohm-cm oui demonstrated, corresponding to a voltage gradient of 2. 0 #V/cm. Richardson, N.E., J.D. McCleave and E.H. Albert, 1976. Effect of Extremely Low Frequency and Magnetic Fields on Locomotor Activity Rhythms of Atlantic Salmon (Salmo salar) and American Eels (Anguilla rostrata). Environ. Pollut., 10(1):65-76. The effect of weak, extremely low frequency (ELF) electric and magnetic fields on the locomotor activity of Atlantic salmon (Salmo salar) and American eel (Anguilla rostrata) juveniles is investigated. Fish were individually exposed to 60 or 75 Hz electrical fields of 0.07 V/m or 0.7 V/m or magnetic fields of 0.5 gauss on alternate days in LD 12:12 or DD light conditions. Neither salmon nor eels showed differences between the level or rhythmicity of locomotor activity on exposed and nonexposed days. Fish were also exposed to a 75 Hz electric or magnetic field for 1h in every 23 h in LL, DD or LD 12:12. None became entrained to a 23 h periodicity. Thus, there is no indication that proposed ELF communications systems would influence the daily activity of Atlantic salmon or American eels. Rommel, S.A. and J. McCleave, 1973a. Sensitivity of American Eels (Anguilla rostrata) and Atlantic Salmon (Salmo salar) to Weak Electric and Magnetic Fields. J. Fish. Res. Bd. Can., 30(5):657-663. Two long distance migrating fish, American eel and Atlantic salmon, showed consistent conditioned cardiac deceleration to weak electrical fields applied perpendicular, but not parallel, to their bodies. At a field with current density 0.167 x 19-4 A/em?, 63 percent of eels were conditioned; at 0.15 x 107 3 4A/cm, 56 percent of salmon were conditioned. This work demonstrates these two species have sufficient electrosensitivity to detect naturally occurring electric fields; and are sensitive to perpendicular fields. Therefore, these fish are able to detect geoelectric fields when swimming parallel to water motion but not when swimming perpendicular to it. Rommel, S.A. and J.D. McCleave, 1973b. Rrediction of Oceanic Electric Fields in Relation to Fish Migration. J. Cons. Int. Explor. Mer., 35:27. American eels and Atlantic salmon are sensitive to very low level electric fields and it is hypothesized that this sensitivity enables them to use the electric fields developed in ocean currents to guide - their long-distance migrations. Both species showed cardiac conditioning to electric fields perpendicular to their bodies. For American eels, results were significant for voltage gradients of -0067 wV/cm in seawater. Atlantic salmon were sensitive to 0.06 “V/cm in seawater. 59 Royce, W.F., L.S. Smith and A.C. Hartt, 1968. Models of Oceanic Migrations of Pacific Salmon and Comments on Guidance Mechanisms. U.S. Fish. Bulletin, 66:441-442. The general oceanic distribution and migratory behavior of Pacific salmon are summarized, and a model of the entire migration is developed for each of three typical stocks. In general, salmon stocks travel "downstreati" in the major current systems within the area defined. The time schedule, rate of travel, and average size of the fish at various stages are described for each of the three stocks (pink salmon of S.E. Alaska and British Columbia, pink salmon of E. Kamchatka, and sockeye salmon of Bristol Bay). On the basis of this summary, the authors believe that salmon migrations could not be performed by migrating or drifting at random, or if they depended upon memorized visual or olfactory cues except for final location of home estuary and stream. The salmon predominantly travel actively with the residual ocaen currents in circular migration routes. Many races could accomplish their migrations by moving down or across currents until close to the mouths of their home streams, where they might recall olfactory cues. Also, ocean currents produce electric potentials in a range that some fish can detect; therefore, salmon might depend for navigation on electromagnetic cues from ocean currents. Scheminsky, F., 1934. Uber die Natum de "Wechselstromnarkose" bei Fischen. Pfltigers Arch. ges. Physiol., 233-371-79. Sheppard, A.R. and M. Eisenbud, 1977. Biological Effects of Electric and Magnetic Fields of Extremely Low Frequency. Inst. of Environmental Medicine, New York University Medical Center, New York, pp. 7-22 - 7-28. Intended as an informational base for assessment of effects associated with human exposure to ELFs, this volume provides a comprehensive review of the international literature on biological effects of low frequency electric and magnetic fields. Topics include hematological and biochemical effects, as well as physiological and behavioral effects in human and non-human species. Effects on migration, navigation and communication in marine species are discussed. Stewart, P.A.M., 1977. A Study of the Response of Flatfish Pleuronectidae to Electrical Stimulation. J. Cons. Int. Explor. Mer., 37(2):123-129. Direct observation on the reactions of flatfish of the Pleuronectidae to electrical stimulation were made by towing a manned sledge supporting an energized electrode array over the sea bed. The electrical stimulus was pulsed DC, ranging in frequency from 4-40 Hz. Involuntary muscular contractions were induced by this stimulus which caused the majority of fish to flee from the electrified zone. Reactions were classified into = a few broad categories and the approximate fish size in each observed event was recorded. The most efficient frequency for inducing flatfish to leave the bottom is around 20 Hz, and that large fish are more strongly stimulated by an electric field than small fish; the latter 60 being a significant demonstration under natural conditions of a theory based on aquarium experiments. Observations were made on the reactions of flatfish to a towed chain to assess its comparative efficiency in forcing fish to leave the sea bed. Straub, K.D., J.Z. Kendrick and H. Jackson, 1972. Effects of Low Frequency Electrical Current on Various Marine Animals. Naval Air Development Center, 72126-Cs. The effects of extremely low frequency AC electric fields on a number of marine animals were examined in the laboratory using stainless steel plate electrodes in a plastic tank to produce current densities in the range of 10-650 A/m2, The studies were conducted at frequencies between 10 Hz and 20,000 Hz. Each animal was observed for its response, e.g., withdrawal of tentacles, contractions of certain muscles, a bioluminescent flash, or rapid swimming. The animals investigated included the sea anemone, mnemiopsis, bay scallops, mud snails, crabs, shrimp, sea squirts, and fish. The most sensitive response was obtained from the green shrimp (Panaeus setiferus) which was sensitive at 75 Hz to current densities below 10 A/m?. At low frequencies fish were stunned and the young ones died at current densities of 40-80 A/m2, while larger fish recovered. Despite the wide variations in the sorts of marine life tested, including large differences in the skeleton which affectsthe current density penetrating the organism, the range of threshold responses at 10 Hz was small, within one order of magnitude for all the organisms. By 100 Hz this range had increased appreciably to almost 2 orders of magnitude. Because of the similarity of the response curves found in all these different animals, and in consideration of other literature they cite, it is suggested that AC currents have their effect at the cell membrane. Street, R., 1976. Electricity as a Navigational Device in Fish. In: Animal Migration and Navigation, Charles Scribner's Sons, New York, pp. 36-50. Some fish, such as the freshwater species Gymnarchus niloticus (Lissmann, 1958), produce slight electrical fields which can detect magnetic fields. Three groups of marine fish are electrogenic, including "stargazers" (small group of bottom fish) and two groups of elasmobranchs, the torpedo rays and skates. Webb, H.M., F.A. Brown and T.E. Schroeder, 1961. Organismic Responses to Differences in Weak Horizontal Electrostatic Fields. Biological Bulletin, 121:413. Mud-snails, Nassarius obsoleta, submerged in seawater were able to resolve a horizontal field difference of 2 V/cm in air at right angles to their body axis, and to exhibit a characteristic orientational response. The experimental field detected by snails in the seawater medium was on the order of fractions of a microvolt per centimeter. Snails also appeared able to distinguish the direction of the very weak 61 gradient across their bodies. The character of the electrostatic response was altered simply by changing the compass direction in the earth's field in which the response was assayed. Electrostatic response was seemingly altered by some natural force effected by geographical orientation of the organism. Zimmerman, M.A. and J.D. McCleave, 1975. Orientation of Elvers of American Eels (Anguilla rostrata) in Weak Magnetic and Electric Fields. Helgolander wiss. Meersunters, pp. 175-181. 62 MAGNETIC FIELD EFFECTS Blakemore, R., 1975. Magnetotactic Bacteria. Science, 190:377. Certain bacteria found in marine sediments move in response to weak DC magnetic fields of the size of the geomagnetic field (0.5 G). Their response to a magnetic field may be related to the presence of chains of iron-rich, crystal-like particles found within membranes in the cytoplasm. The magnetotactic response depends upon the bacterium's ability to move (by flagellar motion) and is not a result of a direct magnetic force on the cell. Brewer, H.B., 1979. Some Preliminary Studies of the Effects of a Static Magnetic Field on the Life Cycle of the Lebistes reticulatus (Guppy). Biophys. J., 28(2):305-314. Lebistes reticulatus was subjected to a continuous treatment of a 500-G homogeneous magnetic field within a specially designed horseshoe Magnet encompassing a small aquarium. The experiment was carried through several generations with the following results: in the first generation, the brood size was normal but the gestation period was reduced by 30%, the second generation had an average reduction of spawn rate of 50% and a reduction of the gestation period of 30%, and in the third generation, reproduction was completely inhibited as long as the fish remained within the magnetic field. Brown, F.A. Jr., 1962. Responses of the Planaria, Dugesia, and the Protozoan, Paramecium, to Very Weak Horizontal Magnetic Fields. Biological Bulletin, 123:264-281. The orientational response of the freshwater planarian, Dugesia dorotocephala, at a given time of solar day undergoes what appears to be a semi-monthly or monthly fluctuation, probably a consequence of the possession of lunar-day rhythm on response to some compass- direction factor. The monthly rhythm in Dugesia is modifiable by a weak magnetic field (0.17-10 gauss). Dugesia differentiates between a horizontal field parallel to the long axis of the body and a field at right angles, and between North and South poles. Furthermore, Dugesia is able to resolve intermediate angular orientations of field with remarkable precision. The response of Dugesia alters its character in passing from a 0.17 to 10 gauss field, suggesting the perceptive mechanism is adapted to such a weak field as the geomagnetic one. There is also suggestive evidence that the protozoan Paramecium also responds to very weak magnetic fields. Brown, F.A. Jr., F.H. Barnwell and H.M. Webb, 1964. Adaptation of the Magnetoreceptive Mechanism of Mud-Snails to Geomagnetic Strength. Biological Bulletin, 127:221-231. The intent of this investigation with mud-snails, Nassarius obsoleta, was to determine at what strength of an abruptly reversed horizontal 63 Magnetic vector the snails would be induced to alter their orientation to the greatest degree. The maximum tendency to alter direction in response to the experimentally reversed horizontal magnetic field occurred when the strength of the reversed field is closest in strength to the earth's (horizontal) natural field (0.17 gauss). There is a persistent effect of experimental magnetic fields deviating from the natural one which remains for three to five minutes after the experi- mental field is removed. Brown, F.A. Jr., W.J. Brett, M.F. Bennett and F.H. Barnwell, 1960. Magnetic Response of an Organism and its Solar Relationships. Biological Bulletin 118(3) : 362-381. The orientation of mud-snails, Nassarius obsoleta, in a constant, symmetrical field (horizontal @ 1.5 gauss) was studied over a two-month period (June 28 - August 29, 1959) at various hours of the day between 5 a.m. and 9 p.m. The orientation of snails in the earth’s natural magnetic field was compared throughout the study with the orientation of snails subjected to the 9- to 10-fold increase in field strength, with fields both parallel and at right angles to the earth's natural field. A daily rhythm in the direction and average amount of turning was found in the snails; the mean paths of those in the two (N-S; E-W) experimentally augmented fields were statistically significantly to the left of the controls, particularly between the hours of 7 a.m. through 9 p.m. The mean amount of turning, whether clockwise or counterclockwise, in the experimental magnetic field was also increased significantly over controls, and similarly exhibited a daily rhythm. Evidence is advanced supporting the hypothesis that the orientation of snails normally includes a true response to the earth's magnetic field (indicates sensitivity as low as 0.17 gauss). Brown, H.R., G.N. Andrianov and 0.B. Ilyinski, 1974. Magnetic Field Perception by Electroreceptors in Black Sea Skates. Nature, 249:178-179. Our experiments showed that a changing magnetic field penetrating the fish evoked the response of neurones in the area acoustico-lateralis, whereas a constant magnetic field failed to influence the electroreceptor system. The characteristic of the response to the changing magnetic field is dependent on the direction of the field; the intensity of the reaction is due to the rate of change of the magnetic field. The smallest change in the magnetic field evoking a neuronal response was found to be 2 gauss-1, obtained on a neurone showing no spontaneous activity. Apparently, this value could be reduced by improving the functional state of the animal. The comparison between the magnetic flux change observed in experimental conditions and that which occurs during natural fish movements (both linear and turning) shows the possibility that the earth's magnetic field may be perceived by electroreceptor apparatus of ampullae of Lorenzini. 64 Brown, H.R. and 0.B. Il'inskii, 1978a. The Ampullae of Lorenzini in the Magnetic Field. J. Comp. Physiol., 126(4):333-341. The impulse activity of single nerve fibers supplying the ampullae of Lorenzini in the Black Sea skate, Raja clavata and Trygon pastinaca, was recorded to study the response of these receptors to various modifications of stimulation with the vertical component of a magnetic field. When the animal was at rest in motionless water an impulse reaction was observed only with changes in magnetic field, a constant field had no effect. The intensity of response was determined by the rate of magnetic field change. The nature of responses to magnetic field changes depended on the orientation of the ampullary canals relative to induced currents in the animal's body and in the surrounding sea water. The intensity of response of a single receptor to magnetic field changes decreased with the shortening of the ampullary canal under study, cutting of the other canals or dissection of the capsule of the ampullary cluster appeared to have no effect. The receptors of the ampullae of Lorenzini were shown to respond to a constant magnetic field when the fish moved in water, or when water was moved with respect to the fish. The character of impulse responses to a constant magnetic field depended on the direction of the field and the direction of movement of either the fish or the water. The relationship between the response intensity and magnetic field, or velocity of water flow is roughly linear. Symmetrical receptors on the right and left sides of the animal's body responded oppositely to stimulation by either increasing or constant magnetic field. Experiments involving compensation for the earth's magnetic field with Helmholtz coils revealed a statistically significant reaction to the vertical component of the geomagnetic field (0.35 G) ac Brown, H.R. and 0.B. Il'inskii, 1978b. Mechanism of Changing Magnetic Field Detection by Ampullae of Lorenzini in Elasmobranchs. Neirofiziologiya, 10(1): 75-83. Investigating the impulse activity from single nerve fibers connected with the Lorenzinian ampullae in Black Sea skates, Raja clavata, the mechanisms of changing magnetic field detection were studied. The receptor responses to magnetic stimulation were caused by induction of electric currents in the fish body or sea water. The peculiarities of receptor responses enables the animal to distinguish magnetic stimuli from any other stimuli. An increase in fish receptor reaction to magnetic stimulation near the coast wall of the tank was observed. The biological significance of magnetic detection by the Lorenzini ampullae was discussed. Halpern, M.H., 1966. Effects of Reproduceable Magnetic Fields on the Growth of Cells in Culture. NASA CR-75121, National Aeronautics and Space Administration, Washington, D.C. The reproduction rate of the simple algae Euglena and Chlorella was accelerated in very low magnetic fields (.001 gauss) and inhibited in high fields (1000 gauss) during one to three weeks of exposure. 65 Hartman, S.A. and G. Claus, 1971. The Effects of Induced Magnetic Field on the Larvae of the American Oyster, Crassostrea virginica. Basteria, 35 (6) 2119-130. Influence of high magnetic fields was tested on larvae of C. virginica at the period of their setting. Two field strengths (35 and 58 gauss) of 2-4 days exposure were employed in configurations either parallel or perpendicular to earth's gravitational field. Magnetic fields at the higher level resulted in 100% larval mortality when perpendicular to gravity for 3 and 4 days exposure; same field 93% mortality when parallel for 3 and 4 days exposure. Shorter exposure to this parallel field had no effect. The lower magnetic field resulted in 100% larval mortality while perpendicular to gravity at 4 days exposure, but was without effect at shorter exposures. When parallel to gravity it affected 20% mortality with a simultaneous doubling of sets at 4 days exposure and had no lethal effect but still increased the number of sets at shorter exposure times. Oyster larvae are considered sensitive indicators of presence of higher magnetic fields and are influenced not only by strength of field but also by direction. Biological mechanism underlying this phenomenon is unknown. James, H.D. and R.W. Dykes, 1978. Some Experiments on Navigation in the Harbour Seal, Phoca vitulina. In: Schmidt-Koenig and Keeton (eds.), Animal Migration, Navigation and Homing, Springer-Verlag, Berlin, pp. 395-404. Seals, captured on Sable Island (43°55'N; 60°00'W) and released 24 hours later in the interior of the island from places with which they are not familiar and from which the sea is not visible, head SSW on the shortest route to the coast. Based on a complex series of experiments, the authors hypothesize seal navigation involves detection of a magnetic meridian coupled with polarized light, audio (sound of surf) and visual cues. James, H. and D. Renoug, 1972. Navigation in Harbor Seals, Phoca vitulina. Symposium on the Biology of the Seal, Univ. Guelph, Ontario, Canada, 14-17 August. Overland navigation of harbor seals at Sable Island was unaffected by horizontal visibility, cloud opacity, wind direction or apparent direction of the sound of the surf. The use of celestial or geomagnetic clues is suggested. Kalmijn, A.J., 1979. Electromagnetic Guidance Systems in Fishes. In: Tenforde (ed.) Magnetic Field Effect on Biological Systems, Proc. of the Biomagnetic Effects Workshop, Berkeley, April 6-7, 1978, pp. 15-18. Kalmijn, A.J. and R.P. Blakemore, 1978. The Magnetic Behavior of Mud Bacteria. In: Schmidt-Koenig, K. and W.T. Keeton (eds.), Animal Migration, Navigation and Homing, Springer-Verlag, Berlin, pp. 354-355. 66 When separated from the substrate, Blakemore's mud bacteria (benthic microfauna) swim back to the seafloor following the earth's magnetic field lines. Magnetotactic response appears to be due to the presence of internal ferromagnetic dipole components of single-domain properties. Kholodov, Yu.A., 1958. Formation of Conditional Reflexes in Fish to a Magnetic Field. In: Proc. of Conf. on the Physiology of Fish, Izd. Akad. Nauk. SSSR, p. 82 (in Russian). In experiments with sticklebacks, exposure to a magnetic field increased motor activity in fish. Activity increased by 64% in a field with strengths of 50 to 150 G. Kholodov, Yu.A., 1974. Influence of Magnetic Fields on Biological Objects. Joint Publications Research Service, Arlington, VA, 230 p. Knudtson, B.K. and J.R. Stimers, 1977. Notes on the Behavior of Elasmobranch Fishes Exposed to Magnetic Fields. Bull. South. Calif. Acad. Sci., 76(3):202-204. Species (3) of elasmobranchs Cephaloscyllium ventriosum, Heterodontus francisci and Urolophus halleri were examined for sensitivity and behavioral responses to magnetic fields of varying magnitude and direction. Each species responded in a unique manner to magnetic stimulation. H. francisci displayed what could be electroreceptor- mediated responses, while responses of C. ventriosum were possibly a result of direct stimulation of nerves and muscles by the magnetic field. Responses of U. halleri suggested orientation along a magnetic axis. Magnetic field strengths that elicited responses were greater than the earth's magnetic field strength. Sensitivity of the electroreceptor organs and the use to which the information they supply is put could vary as a function of the ecology of each species. Free-ranging, epipelagic sharks may use their electromagnetic reception capabilities for fixed-space orientation, while more sedentary, near-shore species May use them to locate live food sources, or not use them at all. McCleave, J.D. and J.H. Powers, 1978. Influence of Weak Electric and Magnetic Fields on Turning Behavior in Elvers of the American Eel Anguilla rostrata. Marine Biology, 46(1):29-34. The turning behavior of elvers of the American eel was studied in an arena in which horizontal electric or vertical magnetic fields could be manipulated. Objectives were (1) to determine if the strength and polarity of a weak DC electric field influenced elver orientation and to determine if any of such influence was due to electric fields generated by the elver's own 7swimming movements 98 electric current density = increased from 107 2 uA/cn2 to 102 pAlem, elvers turned increasingly more toward the anode (in the lower fields tested they turned more toward the cathode). There were no differences in mean turning angles for groups of elvers swimming in four different vertical magnetic fields (0.54 gauss, 67 20.02 gauss, 2.00 gauss and 0.52 gauss reversed direction), suggesting that elvers were not influenced by internally generated electric fields. However, swimming speeds were ane that the generated fields would have been on the order of 107 “4 pal cut or less. Elver orientation apparently could be influenced by asain fields of the magnitude generated by major ocean current systems, but probably are not influenced by electric fields generated by their own swimming in a geomagnetic field. - McCleave, J.D., S.A. Rommel and C.J. Cathart, 1971. Weak Electric and Magnetic Fields in Fish Orientation. Ann. N.Y. Acad. Sci., 188:270-282. Twenty-six American eels were tested for natural or conditioned cardiac deceleration responses to weak electric fields (0.333 x 10-4 to 0.167 x 107 2 wA/ cm) and eighteen Atlantic salmon tested for conditioned deceleration to weak electric fields (0.167 x 107 -2 A/cm). Thirteen eels (Anguilla rostrata) and eight salmon (Salmo wate) were tested for natural or conditioned cardiac deceleration responses to reversals of the vertical component of the geomagnetic field (0.38 gauss), DC or pulsed fields 5 times the vertical component (1.90 gauss), or pulsed reversals of the horizontal component (0.17 gauss). Four out of five eels and salmon showed significantly lower mean test nese than mean control rates when an electrical field (0. 167 ~amp/em 2 ) was applied perpendicular to the body axis. No response when field applied parallel to body. Neither eels or salmon appeared to respond to the magnetic fields. Palmer, J.D., 1963. Organismic Spatial Orientation in Very Weak Magnetic Fields. Nature, 198:1061-1062. The turning response of the green alga Volvox aureus in a weak magnetic field was documented for three experimental conditions: (1) the control condition, with a horizontal intensity of 0.17 gauss (natural geomagnetic field at experimental site), (2) an augmented field of 5.0 gauss with the horizontal component oriented as that of the earth's magnetic field, and (3) a 5.0 gauss field with the north seeking pole directed west (90° out of phase). Significant increases in clockwise turning were noted for conditions 2 (43% increase) and 3 (150% increase). Volvox was shown to be able to perceive magnetism, distinguish between different intensities, and distinguish different directions of magnetic lines of force. Because Volvox is an evolutionarily less complex organism and a direct descendent of one of the earliest forms of life, this discovery emphasizes the deep-seated nature of responsiveness to magnetism. Poddubnyi, A.G., 1965. Some Results of Long-Range Observation of Behavior of Migrating Fish. In: Bionics, Nauka, Moscow, p. 225. se A positive capability for geomagnetic orientation was demonstrated for fish; 87.5% of fish transplanted to a new basin and 50% of local individuals moved in the magnetic meridian in water with uniform hydrophysical indices. 68 Poddubnyi, A.G. and L.K. Malinin, 1976. Orientation of Diadromous and Freshwater Fishes in the Inland Reservoir. In: Acts of the 2nd European Ichthyological Congress organized with the National Museum of Natural History, Paris, UNESCO, 8-15 September. On the basis of the data collected from 320 individuals of 12 species in various water bodies, orientation behavior patterns relating to each condition became apparent. For lakes or reservoirs with uniform conditions navigation is affected by the general direction of the sun's movement, by stars or by the ability to detect the horizontal component of the earth's magnetic field. Quinn, T.P., 1980. Evidence for Celestial and Magnetic Compass Orientation in Lake Migrating Sockeye Salmon Fry. J. Comp. Physiol., 137(3):243-248. Radially symmetrical, four-armed tanks were designed for testing the directional preferences of Oncorhynchus nerka fry as they commenced up-lake migrations following emergence from gravel nests and river migration to the lake. When tested during the day or night, as appropriate for their migration, fry from 2 stocks moved in compass directions corresponding to those which they would have to maintain in their up-lake migration. The directional preferences of one population tested during the non-migratory time of day apparently corresponded to the fry's onshore movement. Orientation was maintained under both overcast and clear skies, and under plastic covers. A 90 degree counter-clockwise shift in the horizontal component of the earth's magnetic field was associated with approximately 90 degree changes in the mean direction of movement of fry at night, even when they were given a view of the sky. During the day, only fish tested in covered tanks displayed redirected movements in the altered field; those tested with a view of the sky showed geographically appropriate movement patterns despite the shifted field. Quinn, T.P., 198la. Magnetic Field Detection in Sockeye Salmon. J. Exp. Zoology, 217:137:142. Previous research has indicated that lake-migrating sockeye salmon fry have compass directional preferences, cued in part by magnetic fields. This paper reports the results of experiments designed to compare the magnetosensory system of salmon with those of other organisms. Unlike birds, salmon fry did not reverse their compass orientation 180° when the magnetic field's vertical component was inverted, but rather displayed northerly (31°) orientation similar to that of fry in two different control conditions (325° and 22°). Magnetized material (possible transducer) was not found in 26 out of 30 fry examined. The material in the other 4 was probably environmental contamination, and not part of a sensory system. The mechanism of magnetic detection in salmon remains unknown. 69 Quinn, T.P., 1981b. A Model for Salmon Navigation on the High Seas. Unpublished. The established movement patterns of homeward migrating Pacific salmon seem best explained by an active orientation system. A combined map- compass-calendar system is proposed. A bi-coordinate grid of magnetic inclination and declination isolines constitutes the map, compass mechanisms previously documented in juvenile salmon include celestial and magnetic orientation, and are proposed to maintain the headings determined from the map sense. An assessment of daylength or the rate of change in daylength (tied to a latitude sense) combines with endogenous circannual rhythms to provide a calendar sense. The range of inclinations, declinations and daylengths in the regions occupied by Pacific and Atlantic salmon are presented. Three types of experiments, designed to test the map hypothesis, are proposed. Richardson, N.E., J.D. McCleave and E.H. Albert, 1976. Effect of Extremely Low Frequency Electric and Magnetic Fields on Locomotor Activity Rhythms of Atlantic Salmon (Salmo salar) and American Eels (Anguilla rostrata). Environ. Pollut., 10(1):65-76. The effect of weak, extremely low frequency (ELF) electric and magnetic fields on the locomotor activity of Atlantic salmon (Salmo salar) and American eel (Anguilla rostrata) juveniles is investigated. Fish were individually exposed to 60 or 75 Hz electrical fields of 0.07 V/m or 0.7 V/m or magnetic fields of 0.5 gauss on alternate days in LD 12:12 or DD light conditions. Neither salmon or eels showed differences between the level or rhythmicity of locomotor activity on exposed and nonexposed days. Fish were also exposed to a 75 Hz electric or magnetic field for 1 h in every 23 h in LL, DD or LD 12:12. None became entrained to a 23 h periodicity. Thus, there is no indication that proposed ELF communications systems would influence the daily activity of Atlantic salmon or American eels. Tesch, F.W., 1974. Influence of Geomagnetism and Salinity on the Directional Choice of Eels. Helgoladnder wiss. Meersonters, pp. 382-396. 70 SEAWATER CHLORINATION Alderson, R., 1974. Seawater Chlorination and the Survival and Growth of the Early Developmental Stages of Plaice, Pleuronectes platessa L., and Dover Sole, Solea solea (L.). Aquaculture, 4:41-53. Bellanca, M.A. and D.S. Bailey, 1977. Effects of Chlorinated Effluents on Aquatic Ecosystem in the Lower James River. J. Water Poll. Control Fed., 49:639. A 96-hour LCs5q of 0.22 mg/1 TRC was found for the decapod, Palaemonetis pegis. For the fish, Menidia menidia, 96-hour LCcg was 0.037 mg/1. Brungs, W.A., 1976. Effects of Wastewater and Cooling Water Chlorination on Aquatic Life. U.S. Environmental Protection Agency, Env. Res. Lab., EPA-600/3-76-098, 45 pp. The literature since 1972 pertaining to wastewater and cooling water chlorination is discussed under the following headings: review papers, chlorinated municipal wastewaters, continuously chlorinated water, intermittently chlorinated water, dechlorination, avoidance, formation of chlorinated organic compounds, aquatic life criteria and application factors, and regulations. Chlorination of both marine and freshwater environments are considered. Capuzzo, J.M., et al., 1976. Combined Toxicity of Free Chlorine, Chloramine and Temperature to Stage 1 Larvae of the American Lobster Homarus americanus. Water Res. Capuzzo, J.M., 1978. The Effect of Temperature on the Toxicity of Chlorinated Cooling Waters of Marine Animals - A Preliminary Review. Marine Pollution Bulletin 10(2):45-47. The effect of temperature on the toxicity of free Cl and chloramine to Acartia tonsa, Brachnionus plicatilus, Crassostrea virginica, Fundulus heteroclitus, Homarus americanus, Oncorhynchus gorbuscha, and Oncorhynchus tshawytscha is reviewed. For all species tested, except the copepod Acartia tonsa, temperature has a synergistic effect on the toxicity of both halogen forms. The effect of temperature in enhancing the toxic effects of chlorinated cooling waters to marine animals may be due to an interaction of uptake rates and regulation of physiological rates, and the greatest enhancement in sensitivity could be expected at the upper limit of a species’ thermal tolerance. Carlson, A.R., 1976. Reproductive Behavior of the Threespine Stickleback Exposed to Chloramines. Master Sci. Thesis, Oregon State Univ., Corvallis, Oregon. a Carpenter, E.J., B.B. Peck and S.J. Anderson, 1972. Cooling Water Chlorination and Productivity of Entrained Phytoplankton. Marine Biology, 16:37-40. Carpenter, J.H. and D.L. Macalady, 1975. Chemistry of Halogens in Seawater. Presented at the Conf. on Environmental Impact of Water Chlorination, Oct. 22-24, 1975, at Oak Ridge Nat. Laboratory. Davies, R.M. and L.D. Jensen, 1975. Zooplankton Entrainment at Three Mid-Atlantic Power Plants. Jour. Water Pollution Control Federation, 47, p. 2130. Davis, W.P. and D.P. Middaugh, 1976. Impact of Chlorination Processes on Marine Ecosystems. In:- Jolley (ed.), Water Chlorination; Environmental Impact and Health Effects, Ann Arbor Science Publishers, Inc., Vol. 2, pp. 283-310. For over 175 years chlorine gas has been used in industrial, biocidal ,and disinfection applications. The chemistry of chlorine in freshwater is farely well known, but long-range effects on marine organisms and ecological communities have been barely studied. This paper presents a theoretical degradation model of chlorine added to marine waters. Additionally, it summarizes literature reporting laboratory or ecological effects of chlorination, pertinent through 1977. DeGraeve, G.M., W.J. Blogoslawski, W.A. Brungs, J.A. Fava, B.J. Finlayson, T.P. Frost, T.M. Krischan, J.W. Meldrim, D.T. Michand, R.E. Nakatani and G.L. Seegert, 1979. In: A Review of the EPA Red Book: Quality Criteria for Water. Thurston, R.V., et al. (eds.), Water Quality Section, American Fisheries Society, Bethesda, Maryland. Dinnel, P.A., Q.J. Stober and D.H. DiJulio, 1979. Behavioral Responses of Shiner Perch to Chlorinated Primary Sewage Effluent. Bulletin of Environmental Contamination and Toxicology, 22(4-5):703-714. Twenty duplicate tests were conducted with 0% effluent and 10 duplicated tests, each with 1%, 5%, 10%, 15% and 20% vol/vol chlorinated effluent to determine the behavior response of Cymatogaster aggregata to chlorinated primary sewage effluent in seawater. Shiner perch showed a statistical preference for 1%, 5% and 10% chlorinated effluent, avoidance of 15% and 20% effluent, and random movement in the test tank when effluent was not present. Subjective analyses of shiner perch behavior from video tape recordings yielded similar conclusions. Shiner perch avoided levels of chlorinated sewage which would have been lethal to them in 96 hr. However, they were attracted to effluent concentrations = which produce sublethal damage to the integrity of the gills and changes in blood chemistry and blood cell morphology of coho salmon. Chlorine may be partly responsible for the attraction-avoidance pattern exhibited by shiner perch. The variability observed in fish behavioral responses to Cl and chlorinated sewage effluent may provide a partial answer to the differences in fish distribution sometimes observed in discharge areas. 42, Galtstoff, P.S., 1946. Reactions of Oysters to Chlorination. U.S. Fish and Wildlife Serfice, Research Report 11. Gentile, J.H., et al., 1974. Power Plants, Chlorine and Estuaries. Presented at the 104th Annual Meeting of the American Fisheries Society, Sept. 9-11, Honolulu, Hawaii. Geoffrey, I.S. and D.P. Middaugh, 1978. Seasonal Chronic Toxicity of Chlorination to the American Oyster, Crassostrea virginica. In: Water Chlorination: Environmental Impact and Health Effects, V. 2, pp. 311-328. Lethal and sublethal effects of chlorination to adult oysters (Crassostrea virginica) were observed during chronic exposures on a seasonal basis. Results show that chronic exposure of oysters to chlorine-produced oxidants (CPO's) can produce mortality at high concentrations and severe sublethal effects at low levels (reduced feeding and avoidance of CPO, reduced tissue formation, reduced gonad size). Ginn, T.C. and J.M. O'Connor, 1978. Responses of the Estuarine Amphipod Gammarus daiberi to Chlorinated Power Plant Effluent. Estuarine Coastal Mar. Sci., 6:459. A l-hour LC59 value of 1.85 mg/1 total residual chlorine was determined for the estuarine amphipod Gammarus daiberi. Holland, G.A., J.E. Lasater, E.D. Neumann and W.E. Eldridge, 1964. Toxic Effects of Organic and Inorganic Pollutants on Young Salmon and Trout. Dep. Fish. Res. Bull. No. 5, State of Washington, 264 pp. Holmes, N., 1970. Marine Fouling in Power Stations. Marine Poll. Bull., 12105). Hoss, D.E., L.C. Coston and D.R. Colby, 1977. Synergistic Effects of Exposure to Temperature and Chlorine on Survival of Young-of-the-Year Estuarine Fishes. In: Physiological Responses of Marine Biota to Pollutants. Vernberg, W.B. (eds.), Academic Press, Inc., New York, pp- 345-355. The combined effects of heat and chlorine that would be encountered by entrained fish at estuarine and offshore power plant sites was investigated by the authors. The experimental fishes used were southern flounder (Paralichthys lethostigma), striped mullet (Mugil cephalus), Atlantic silverside (Menidia menidia) and mojarra. (Eucinostomus argenteus) all young-of-the-year fish. This report on the combined i effects of chlorine and temperature indicates that thermal shock increases the toxicity of chlorine to the species of fish tested. 73 James, W.G., 1967. Mussel Fouling and Use of Exomotive Chlorination. Chem. Ind. (Lond.), 24:994-996. Jolley, R.L., 1973. Chlorination Effects on Organic Constituents in Effluents from Domestic Sanitary Sewage Treatment Plants. Oak Ridge Nat. Laboratory, Rept. No. ORNL-TM-4290, Oak Ridge, Tennessee. Jolley, R.L., G. Jones, W.W. Pitt and J.E. Thompson, 1976. Chlorination of Organics in Cooling Waters and Process Effluents. In: Jolley, R.L. (ed.), Water Chlorination, Environmental Impact and Health Effects, Ann Arbor Science Publishers, Inc., Vol. 1, pp. 105-138. Kalmaz, E.V., 1978. Added Residual Chlorine in Marine Environments. Institute of Environmental Sciences: 1978 proceedings, pp. 216-219. Studies made on the chlorination of freshwater systems do not have much application to marine environments of coastal and estuarine waters because seawater has a relatively high concentration of Br compared to typical added residual Cl. This Br causes the reduction of all Cl to chloride, forming hypobomous acid and hypobromite. If ammonia N levels are high, however, the formation of monochloramine may compete with Br oxidation. The presence of ammonia therefore is a major factor in fish toxicity of halogen residuals. While most fish and other aquatic mammals can ingest chlorinated organic compounds from food and waters in which they live, those which use large quantities of water to obtain 09 accumulate large quantities of these compounds in their tissues. In trying to assess the true impact of residual Cl on marine organisms, it is important to identify the reaction products of Cl in seawater, since the potential toxicity of such compounds is unknown. Special techniques, mathematical modeling, computer simulation, and sophisticated apparatus have yet to be developed which will enable the measurement of low concentration chloramines, bromamines, and trace organochlorine compounds, which are more persistent than free Cl, and hence, more toxic. There is a need for reliable, a priori, predictive tests techniques to assess the inherent potential of substances that induce adverse biological effects, and an urgent need for a more efficient method of establishing standards for toxicants produced from the chlorination of water. Liden, L.H., D.T. Burton, L.H. Bongers and A.F. Holland, 1980. Effects of Chlorobrominated and Chlorinated Cooling Waters on Estuarine Organisms. Water Pollution Control Federation. Journal, 52(1):173-182. Toxicities of chlorobrominated and chlorinated cooling waters to selected estuarine food-chain organisms were investigated during an on-site power plant study. Bromine chloride (BrCl) and Clz residuals apparently have similar toxicities to estuarine organisms. Survivals were similar among juvenile Atlantic menhaden (Brevoortia tyrannus) and spot (Leiostomus xanthurus) after exposures to BrCl and Cly treated condenser effluents. Juvenile American oysters (Crassostrea virginica) and brackish water clams (Rangia cuneata) had no halogen-attributable mortalities after 15-d exposures. Similar survival reductions were recorded for copepods 74 (Acartia tonsa) subjected to BrCl or Clj residuals (< 0.100 mg/1) for 24 hr. Increases in 0) evolution (77-388%), carbon-fixation (40-712) and respiration (56-1,276%) rates of entrained phytoplankton were recorded from both chlorobrominated and chlorinated samples. Mattice, J.S. and H.E. Zittel, 1976. Site-Specific Evaluation of Power Plant Chlorination. Jour. Water Pollution Control Federation, 48(10):2284- 2307. McLean, R.I., 1972. Chlorine Tolerance of the Colonial Hydroid Bimeria franciscana. Chesapeake Sci. 13(3):229-230. Euryhaline colonial hydroid Bimeria franciscana experimentally exposed to various concentrations of chlorine(0.1, 1.0, 1.5, 2.5, 3.5, 4.5 ppm) for 1-3 hrs and were returned to their natural habitat. Growth occurred in all colonies but was slightly inhibited in colonies exposed to higher chlorine concentrations. McLean, R.I., 1973. Chlorine and Temperature Stress on Estuarine Invertebrates. J. Water Pollut. Control Fed., 45(5):837-41. Five species of estuarine invertebrates subject to entrainment in the cooling water system of a steam electric station were exposed experi- mentally to chlorine stresses simulating plant operations. Estuarine water with 2.5 mg/l total chlorine residual resulted in 80% mortality in the barnacle nauplii Balanus sp. and 90% in the copepod Acartia tonsa during 5 min exposure. Two amphipods (Gammarus sp. and Melita nitida) and one species of shrimp (Palaemonetes pugio) exhibited greater tolerance to chlorine stress. Meldrim, J.W. and J.A. Fava, 1977. Behavior Avoidance Responses of Estuarine Fishes to Chlorine. Chesapeake Sci., 18(1):154-157. Meldrim, J.W., J.J. Gift and B.R. Petrosky, 1974. The Effect of Temperature and Chemical Pollutants on the Behavior of Several Estuarine Organisms. Ichthyol. Assoc., Inc., Bulletin, 11:1-129. Middaugh, D.P., L.E. Burnett and J.A. Couch, 1980. Toxicological and Physiological Responses of the Fish, Leiostomus xanthurus, Exposed to Chlorine Produced Oxidants. Estuaries, 3(2):132-141. The sublethal and lethal effects of chlorine produced oxidants (CPO) on juvenile spot, L. xanthurus, were investigated in flowing water tests conducted at 30deg+/-idegC and 26-30/00 salinity. Short-term S LTI59 (median lethal time) tests were conducted at 2 nominal sodium hypochlorite (NaOCl) concentrations -1.0 and 1.4 mg/1 (respective measured CPO concentrations 0.09 and 0.12 mg/1) which were sublethal in 2.880 min exposures and at 3 nominal concentrations 1.6, 1.8 and qd) 3.2 mg/1 NaOCl (respective measured CPO concentrations 0.13, 0.20 and 0.37 mg/1) which were acutely toxic. Opercular ventilation rates in exposed spot were much higher than in control fish, but returned to rates only slightly above those of controls during the latter portion of the sublethal CPO exposure. Opercular rates at the acutely toxic CPO concentrations remained much higher than control rates until the exposed fish died. Blood pH after 2,880 min of exposure to the sublethal concentrations of CPO, or at the respective estimated LT59 for lethal concentrations, showed significant decreases. Oxygen uptake by spot was depressed at all of the measured concentrations of CPO tested. Gill respiratory epithelial tissues sloughed away from the underlying pillar cells. Complete denudation of circulatory tissues and hemangiectic secondary lamellae were observed in gill tissues from fish exposed to the highest CPO concentration of 0.37 mg/l. Roberts, M.H. Jr., et al., 1975. Acute Toxicity of Chlorine to Selected Estuarine Species. Jour. Fish. Res. Bd. Can., 32:2525. Roberts, M.H. Jr., and R.A. Gleeson, 1978. Acute Toxicity of Bromochlorinated Seawater to Selected Estuarine Species with a Comparison to Chlorinated Seawater Toxicity. Marine Environmental Research, 1(1):19-30. Various estuarine species previously used for tests of Cl toxicity were tested for toxicity of bromine chloride (BrCl) in a continuous flow system. The most sensitive species were oysters (Crassostrea virginica larvae and juveniles) and copepods (Acartia tonsa) with 48-hour LCsgs of 0.10-0.21 mgBrC1/1. Palaemonetes pugio was most tolerant with a 96-hr LC5q of 0.70 mgBrC1/1. The fish species tested (Menidia menidia, Brevoortia tyrannus, and Leiostomus xanthurus) all had a 96-hr LC5q of 0.21-0.23 mgBrC1/1. When the LCsgs are expressed as equivalents/litre, BrCl is 2-4 times less toxic than Cl2. The ranking of species in terms of sensitivity is the same for both disinfectants. Bromine chloride decays more rapidly than Cl2 at higher ammonia levels (0.25 mg ammonia-N/1). The question of chemical speciation is discussed with particular reference to the different toxicities. Roberts, M.H. Jr., E. Laird and J.E. Illowsky, 1979. Effects of Chlorinated Seawater on Decapod Crustaceans and Mulinia Larvae. Final Report 14, EPA/600/3-79/031. Eggs and larvae of decapod crustaceans and Mulinia lateralis were exposed to chlorinated seawater for varying periods in continuous flow systems. Mortality, developmental rate and general behavior were recorded. Tests with chlorine-induced oxidants (CIO) resulted in 96-hr LC5Q values of 0.10 mg/1 for the decapod zoeae of Panopaeus herbstii and Pangurus longicarpus, with delayed development es noted at 0.02 mg/1 for these species. Mulinia embryos had a 2-hr LCs5q of 0.072 mg/1. 76 Roesijadi, G., D.M. Jacobsen, J.R. Bridge and E.A. Crecelius, 1979. Disruption of Magnesium Regulation in the Crab Cancer productus Exposed to Chlorinated Seawater. Mar. Environ. Res., 2(1):71-84. Exposure of the crab C. productus to Cl seawater resulted in alterations in haemolymph solution and Mg concentrations. Regulation of both ions So was essentially abolished at chlorination levels approaching the 96-hr LC59. Suggested effect on activity of bladder wall. A four-fold increase in ammonia excretion was noted at 0.68 mg/l total residual chlorine. Stober, Q.J. and C.H. Hanson, 1974. Toxicity of Chlorine and Heat to Pink (Oncorhynchus gorbuscha) and Chinook Salmon (0. tshawytscha). Trans. Am. Fish. Soc., 103:659. Stober, Q.J., P.A. Dinnel, E.F. Hurlburt, D.H. DiJulio, S.P. Felton and R.E. Nakatani, 1978. Effects of Seawater Chlorination on Marine Organisms. College of Fisheries, Univ. Washington, Tech. Rpt. UW-NRC-9, 134 pp. A summary of seawater chlorination chemistry and analysis of methods for measurement of chlorine-produced oxidants in seawater are presented as preface to results of bioassay studies with coho salmon, shiner perch and sand dollar. Bioassays with coho salmon and shiner perch indicate coho are more sensitive to chlorine when under 7°C thermal stress. Chlorine bioassays with sand dollar sperm found that successful fertilization of eggs was reduced following 5-min exposures of sperm to concentrations of 2 to 20 mg/1 TRO. Filtered, chlorinated seawater was less toxic to sperm than unfiltered seawater. Behavioral response of marine fish to chlorinated seawater was species dependent. Coho salmon actively avoided chlorine above 2 mg/1 TRO in seawater of all temperatures tested. Shiner perch, however, did not avoid chlorine at less than 175 mg/1 TRO. Perch were attracted to seawater with a temperature of 3° and 7°C above ambient and chlorinated to 10, 25, 50 and 100 mg/1 TRO. Stober, Q.J., P.A. Dinnel, E.F. Hurlbert and D.H. DiJulio, 1980. Acute Toxicity and Behavioral Responses of Coho Salmon (Oncorhynchus kisutch) and Shiner Perch (Cymatogaster aggregata) to Chlorine in Heated Seawater. Water Research, 14(4):347-354. The acute toxicity and behavioral response to chlorinated and heated seawater was determined for coho salmon smolts and 1-3 mo. old shiner perch. The LC59 values were determined for 7.5, 15, 30 and 60 min exposure times; 13°, 16°, and 20°C temperatures; and total residual oxidant (TRO) concentrations ranging from 0.077 to 1.035 mg/l. The mean 60 min LCsg for shiner perch was significantly reduced from - 308 mug/1 TRO at 13°C to 230 mug/1 TRO at 20°C. The 60 min LC5Q for coho salmon decreased from 208 mug/1 TRO at 13°C to 130 mug/1 at 20°C. The LCs5g values for coho salmon in chlorinated seawater averaged 55% of those for shiner perch. The relationship between TRO concentration, 77 exposure time, and percent survival in chlorinated seawater at 13°C is presented for both species. A significant avoidance threshold for coho salmon occurred at 2 mug/1 TRO and was reinforced with increasing temperature. A significant avoidance threshold for shiner perch occurred at 175 mug/1 TRO, while a significant preference response at 16° and 20°C occurred at 10, 25, 50 and 100 mug/1 TRO. The ecological implications of the toxicity tests and the behavioral responses are discussed. Sung, R., D. Strehler and C. Thorne, 1979. Assessment of the Effects of Chlorinated Seawater from Power Plants on Aquatic Organisms. Contract 68-02-2613. EPA/600/7-78/221. U.S. Environmental Protection Agency, 1976. Quality Criteria for Water. EPA-440/9-76-023, Washington, D.C. Ward, R.W. and G.M. DeGraeve, 1978. Acute Residual Toxicity of Several Wastewater Disinfectants to Aquatic Life. Water Resources Bulletin, 14(3):696-709. Wastewater toxicity, with regard to Cl, bromine chloride, and ozone content, was tested with several species of cyprinids, salmonids, centrarchids, and the freshwater invertebrate, Daphnia magna, using effluent from a wastewater treatment plant at Grandville, Michigan. Effluent exposure times were 96-hr for fish and 48-hr for D. magna. Chlorinated effluent exhibited the highest residual toxicity, based on LCsg concentrations and mortality frequency. Dechlorination with sulfur dioxide eliminated residual toxicity, and test animals tolerated residual sulfite adequately. Residual bromine chloride was present at lower levels than Cl in secondary effluent and was less toxic; it was potentially harmful to aquatic life, however, at sufficient concentration. Ozone was the least toxic of the disinfec- tants, primarily due to its rapid dissipation in water. Disinfectant choice would depend on the volume of wastewater treated, dilution potential, receiving water use, climate, and economics. Waugh, G.D., 1964. Observations on the Effects of Chlorine on the Larvae of Oysters, Ostrea edulis L., and Barnacles, Eliminius modestus. Darwin Ann. Appl. Biol., 54:423-440. 78 APPENDIX B INFORMATION PROVIDED BY ASEA AS LISTED BELOW: Elstrommens inverkan pa havsfaunan: W. Deines, Stockholm. Repring from ERA 1949, h.12. (The Influence of Electrical Current flow on Sea Life). Beeinflussungsfragen: LFS560a LFA 133a. page 4 (a. Influence on Communication Cable b. Influence on Ships' Compasses ). Information 4809 574: Experience of earth return gained from experimental investigations and commercial installations. The Anodic Earth Electrode for the Konti-Skan HVDC Link: E. Andersen, N.R. Nielsen, May 1966 Direct Current. A survey of corrosion aspects related to the operation of electrodes for HVDC ground return: I Liden, H. Martensson, (CIGRE 1469(SC). Supplement to (5) above. Second supplement to (5) above. 79 Dealt with by Our date Our reference | B Hammarlund, LFS Ludvika LFS 479 LK i 1981, September 25 { Copy for ASEA Inc. ‘ASKS Mr Donald L Shira WHITE PLAINS, N.Y. 106 04 USA Chief, Planning Division Att.: Mr-J O'Hara For the attention of LEA < (9472) 81-03 5000 Watkeons 5 3 Department of Energy Alaska Power Administration P O Box 50 * JUNEAU, Alaska 99802 USA Your date Your reference August 19, 1981 Dear Sir, Information about ground current electrodes and magnetic field due to d.c. transmissions. As mentioned in the letter by Mr John O'Hara our knowledge in some of the areas outlined is limited. Regarding impact on species (fish) from d.c. electrodes we can only refer to some experiments made in the early days of HVDC, described in Swedish according to attached copy. We also refer to ETZ-B Bd 20 (1968) H17. As to corrosion effects lots of papers etc. have been provided. Attached CIGRE reports present the corrosion experience from existing HVDC projects. Some literature references are also given. Further references can be obtained from AEEI CP63-388. An annotated Bibliography of HVDC transmission (1932-1962) and IEEE 31-S60 Same title (1963-1965). Impact on magnetic compass is treated in attached Information LFS 560a (in German) which was written for a specific case. The equations given are, however, sufficient to calculate the conditions in each separate case, i.e. for other depth and current value. atc 80 iia srausiacads Tatne { Ansvarig: POR 917 0907-AA {989) 80-12 100000 Wives ASE Enclosures: (MT) Ludvika, 1981, September 25 Page 2 LFS 479 LK Mr Donald L Shira JUNEAU, Alaska 99802 USA We have no indication that a reasonable d.c. magnetic field has any significant impact on free living species. Refer however, to the French paper mentioned in attached page 4 of LFA 133a. We hope this information will help you in your investigations. Yours faithfully, ASEA AB HV Switchgear and HVDC Convertor Division HVDC Equipment Marketing Office Lennart Carlsson 4 Skil Stra song c ill - Elstrémmens inverkan pa havsfaunan: W Deines, Stockholm. Reprint from ERA 1949, h. 12. - Beeinflussungsfragen: LFS 560a - LFA 133a, page 4 - Information 4809 574: Experience of earth return gained from experimental investigations and commercial install- ations - The anodic earth electrode for the Konti-Skan HVDC link: E Andersen, N R Nielsen, May 1966 Direct Current - A survey of corrosion aspects related to the operation of electrodes for HVDC ground return: I Lidén, H Martensson, CIGRE 14-69 (SC) - Supplement to above paper - Second supplement to above paper 81 AS - A Inc. il “at Alesha. September 2, 1981 98S ne Mr. Donald L. Shira Chief, Planning Division Department of Energy Alaska Power Administration P. 0. Box 50 Juneau, Alaska 99802 Dear Mr. Shira: Thank you for your recent letter expressing interest in information regarding environmental aspects of a DC underwater cable link in Alaska. ASEA has had extensive experience in supply of HVDC systems utilizing submarine cables - however, our knowledge in some of the environmental areas you have outlined is somewhat limited. Nevertheless, we wil] review what information is available within the company as well as from some of the utilities presently operating such HVDC cable arrangements and report back to you during September. JJO'H/n1 cc: | Dept. LES ASEA, Ludvika U.S.A. HEADQUARTERS WHITE PLAINS, New York 4 New King Street 10604 Tel. (914) 428-6000 Telex 137401 OFFICES ARLINGTON HEIGHTS, IL 717 W. Algonquin Rd. 60005 Tel. (312) 640-6630 Telex 255279 BELLEVUE, WA 11058 Main Street 98004 Tal sone) A81-2AIA Very truly yours, ASEA Inc. Seo eel hn J. O'Har Vice Presi HOUSTON, Texas 15760 W. Hardy Street 77060 Tel. (713) 445-2800 Teiex 792829 PITTSBURGH, PA Bigelow Apartments 1924 15219 Tel.(412) 391-8403 -—~ Telex 866372 82 SAN MATEO, CA 66 Bovet Road 94402 Tel. (415) 574-5400 Telex 2*266 TROY, Mi 1176 East Big Beaver Rd. 48084 Tel. (313) 528-3630 Telex 230419 RELAY & CONTROL DIVISION YONKERS, NEW YORK 1 Odell Plaza 10701 Tel. (914) 969-1900 Telex 646564 ASEA TECHNICAL SERVICES, INC. LAVERGNE, TN 1610 Heiiquaker Bivd. 37086 Tel. (615) 793-7791 Sartryck nr ERA 1949, 2. 12. -Elstrommens inverkan pa havsfaunan Av civilingenjor W Deines, Stockholm I foregaende hafte av ERA framférdes resulratet av en undersékning av den planerade fram- tida férbindelsen mellan kraftnaten pa fastlandet och Gotland. Kraftéverféringen planeras ske med hégspiind likstrém och med enledarkabel till Gotland och iteriedning genom vattnet. Overféringsavstinder blir ca 9 mil och man har riknat med ett Sverfdringsbehov vid en férsta utbyggnad av ca 20 MW vid en likspinning av 100 kV. I samband med denna undersékning har Vartenfallsstyrelsen och Fiskeristyrelsen gjort en del férsék med likstrémséverféring ge- nom vattnet fdr att utréna om fisken, eller Gverhuvud taget havsfaunan, paverkades av denna strém. Har presenteras en utforligare redogérelse Gver dessa férsék. Es fGrutsattning for en enledar-likstrémséver- féring ar, att djurlivet i den andra »ledaren» — ha- vet — ej tar nagon skada. Annars skulle eventuella krav fran fiskerindringens sida kunna_ omintet- géra vinsten med endast en kabel i stallet for tva. Man har vid tidigare férsok, som dock hade helt andra ml, observerat, att bl. a. skaldjur sdkte sig till den ena elektroden. Vidare har i dagspressen setts upp- gifter om elektriskt fiske, men detta utfGres i allmin- het i sétvatten och i mindre bickar, dar man har helt Elektroa Linddajuper Elextrod Horns posr- Linddsunder Karta dver farsdksomradet, Skala ca 1: 20 000, andra férhallanden dn i ppna haver. Detta tydde pa att djurlivet kunde taga skada, atminstone i narheten av elektroderna, varfér det ej ansags tilltyllest att en- dast studera inverkan pa fiskarna utan ven pa plank- toniska organismer och faunan i bottenlerans Oversta skikt. En skadlig inverkan hir kunde indirekt medfora fara for fiskbestandet, di dessa organismer till stor del ar tiskarnas féda. Vidare borde genom regelbundna vattenprov under- sdkas, om elektrolysen hade nagot inflytande pa vatt- rets sammansittning. En eventuell fordndring hirav kan givetvis ocksa skada djurliver. Fiskeristyrelsen utsag fil. dr H Héglund att vara ledare fér den biologiska delen av fdrséket och dr phil. F Koczy for den hydrogratiska. Férséken bér likna verkliga férhallanden Det stod redan fran bérjan klart, att férsdken, sd lange som mdjligt, borde géras i Sverensstimmelse med en verklig kraftéverféring bade elektriskt och fiskeri- 83 621.315.051.2.024 :639.2.039 tekniskt. Den planerade Gotlandséverféringen togs da som monster, och i enlighet harmed valdes trakten kring Vastervik som férsdksplats. Sjailva likriktarsta- tionen forlades till Horns postbrygga ca 7 km SO om Vastervik och kraftéverféringen igde rum mellan den- na brygga och Katsholmarna ca 1 000 m NO hirom tvars dver en vik, Lindédjupet. Elektroden vid Kats- holmarna lag inne i en ca 150 m lang och grund vik, Stora Fartarmen. I denna vik fanns, ett mycket rikt bestand av smafisk och ryggradslésa djur, vartér det ansags limpligt att lagga den ena elektroden har; i verkligheten skulle man givetvis ej placera en elektrod inne i en sadan vik. Elektroden vid postbryggan dir- emot lag, eller rattare sagt hingde, ett tiotal meter ut frin land pa djupt vatten. Mellan dessa-bagg¢ punk- ter skulle alltsa en likstrém pa ca 200 A Overféras. Det kan tyckas, att ett avstand av 1 coo m svarar illa mot en verklig Sverféring pa kanske hundratals kilometer, men nar man har med en nagorlunda ut- bredd vatrenmassa att géra, spelar avstandet mellan elektroderna ingen roll, om detta dr stort i férhallande till elektrodernas geometriska dimensioner. Det hu- vudsakliga spanningsfallet mellan elektrod och vat- _ ligger namligen i elektrodernas omedelbara nir- et. Ej heller spelar spanningen mellan kabeln och vatt- net nagon roll. Denna kan vid en verklig Sverféring vara 100 kV eller mera, medan det vid ett fOrs6k ric- ker med en spinning, som férmar driva runt den dnskade strémmen. Man vill ju endast studera férhal- landena i vattnet och dessa ar alltsi direkt reprodu- cerbara, om man anvander den verkliga strémmen. Likstr6mmen erhdlls fran torrlikriktare, vars ena De fem magnetitelektroderna i sténgets mitt. pol var direkt ansluten till elektroden vid postbryg- gan, medan den andra polen var kopplad cll elektro- den vid Katsholmarna medelst en ca 1 100 m lang sj6- kabel. Fér att driva runt denna strém pa 200 A er- fordrades en likspanning pa ca 280 V, dvs. motstin- det einai enna BL RRA var ca 1,4 Q. P% grund av vattnets salthalt urvecklas klorgas vid anoden. Bestar elektroden av jarn, bortgar inte kloren T gasform utan bildar jarnklorid, vilken i sin tur oxi- deras till jarnhydroxid och saltsyra. Resultatet av den- na process blir, att elektroden mycket snabbt korrode- rar och att vattnet i viss man férorenas. Man bér i stallec anvinda magnetitelektroder, vilka ej angripes av kloren. Vid katoden har man ej nagra korrosions- problem, men en viss, om ock betydelselés, férorening erhalles aven har pa grund av hydroxidbildning. Elektroden pa fastlandssidan bestod av ett ca 2m lingt gjutjirnsrér med roo mm diameter, som hingde ned i vattnet. P2 Katsholmssidan provade man sig fram med olika elektrodutformningar och olika ma- terial. Bl. a. anvande man slingor och ringar av galva- niserad jarntrad, galvaniserade platar, gjutjarns-, gra- tit- och magnetitelektroder. Bottenfaunan och planktoniska organismer under- sdkes Fér att man skulle f& en objektiv bedémning av strémmens eventuella inverkan pa djurlivet i botten- lerans dversta skikt togs, nagra dagar innan stro6mmen slapptes pa, bottenprov pa fem olika platser. Fyra »stationer» lig pe sammanbindningslinjen mellan elektrodcrna, varav en inne i Firtarmen, medan den femte var en kontrollstation, som lag ca 10 km NV om Lindédjupet. Individerna per djurart riknades och bestiimdes per ytenhet. Framfor allt forekom tre arter, namligen Pontoporeia affinis (en marla), Corophium volutator (ett rikdjur) och Macoma_baltica (lilla Sstersjémusslan). Sarskilt faunan inne i Fartarmen var mycket individrik men artfattig. Vid provtagningen dir fére eléverféringen riknades ca 4 000 individer pa 0,1 m*, varav ca 3 000 var Corophium. Efter 14 dagars drift togs ater ett prov och da hade antalet sjunkit till 285, for att efter ytterligare 14 dagar ned- ga till 55 per 0,1 m*. Med stérsta sannolikhet kan dock denna katastrof ej tillskrivas sjélva strémmen utan sekundirverkningar genom elektrolysprodukter, fram- for allt jarnhydroxid, som anrikades i den tranga vi- ken under forsdkets férsta dagar. P& de dvriga sta- tionerna kunde ej nagon minskning av bottentaunan observeras, itminstone ej nagon minskning, som med sikerhert kunde tillskrivas stréméverféringen. Vid ett sadant férsék maste man ju alltid rikna med en mingd andra faktorer, sisom indrade temperatur- och strém- ningsférhallanden, indrade uppehallsplatser fdr en arts olika stora individer osv. For en massdéd av bot- tenfaunan liknande den inne i Fartarmen behéver man givetvis ej vara ingslig vid en verklig Sverféring, di elektroderna ej kommer att liggas inne i en grund vik, och man dessutom kommer att undvika jarnhydroxid- bildning. For sikerhets skull gjordes iven prov med ett 50- tal Corophium i en liten bur. Buren befann sig ca 4 m frin elektroden i ett dygn med strémmen sluten, utan att dess innevanare tog nagon synbar skada. De minsta organismerna i vattnet, plankton, togs upp med en ytterst finmaskig hav. Den slurgiltiga be- arbetningen av dessa havningar dr annu ej klar, men 84 Elektrodernas placering i Fartarmens yttre dei med stangets lage vid de temporGra fdrséken med strémming. en preliminar granskning visar ej nagra stérre fér- andringar mellan de olika provtagningarna. Direkta iakttagelser av faunan i elfaltet Férutom ovan namnda rika bottenfauna fanns iven mycket stora bestind av smafisk inne i Fartarmsvi- ken. Salunda férekom en mangd stim av léja, spigg och elritsa, som huvudsakligen héil till i strandvege- tationen. Viken inspekterades dagligen under hela for- sékstiden, bade nar strémmen var bruten och nar den var sluten. Nagon minskning i stimmens antal eller dindrade uppehallsplatser kunde ej férmarkas. Poten- tialfalret hade ak delvis ritt avsevard styrka inne i viken, men det syntes ej bekomma fiskarna nagot. Aven omkring den vertikala elektroden vid postbryg- gan kunde man mycket ofta f& se stora stim av ett litet kriftdjur, Neomysis vulgaris, som manga ganger var sa nira elektroden som 1 4 1,5 m utan att de reagerade pa minsta vis. Narmare in sa kunde man dock aldrig se, att de kom. Till de direkta iakttagelserna av fisken kan ven ekolodning efter strémmingsstim raknas. Fiskeriin- struktérens i Vastervik bat hade ekolodsutrustning och denna bat kryssade fram och tillbaka Sver Lindé- djupet, medan lodet hela tiden registrerade. Harvid var givetvis strémmen bruten. Uppricktes s4 ett strém- mingsstim, kastades en markesboj, varefter baten ater- vande till denna plats. Till saken hor, att stimmen vid limplig vaderlek rér sig mycket litet under en begrinsad tid. Nir sa stimmert iterfanns, lade sig baten dver detta och medelst radio dirigerades strommens slutning och brytning sa ofta som méjligt under den tid stimmet kunde hallas. Hade strémmen, och di huvudsakligen dess slutning, haft nagon inver- kan, borde registreringen av stimmet direkt fOrsvunnit fran ekogrammer. Detta blev dock aldrig fallet, uran fisken férflyttade sig fullt normale ett temtiotal me- ter i alla riktningar, liksom den gjort i strémlést till- stand. Ej heller i strémbrytningsdgonblicker kunde na- gon reaktion markas. Langtidsférsék med fisk i burar Burarna placerades i mynningen av Fartarmsviken. Dessa hade en volym av ca 1 m® och forankrades mel- lan 4 och ro m fran elektroderna. I burarna hade fér- sdksdjuren, sdsom torsk, gidda, abborre, 4l, braxen och mért, stangts in. Dessa vistades sedan kontinuer- ligt i strémfaltet upp till ro dygn, utan att de tog na- gon pavisbar skada, vare sig elektroden var anod eller katod. Som ett kuriosum kan namnas, att ett par abbor- TemporGra fdrsdk med braxen vid katoden, Fiskarna simma med buken i vadret. rar t. 0. m. lade rom under tiden. Att nagra fiskar dog under forsékstiden kunde givetvis ej undvikas, men de som avied var delvis redan fére forsdket i da- lig kondition. A andra sidan anvandes ett parti torsk under hela tiden, 30 dagar, och dessa fiskar hade di delvis f&tt tjanstgéra som forsdksdjur vid de tempo- rira férséken, som var betydligt mera pafrestande fdr fisken. Vid forsdkstidens slut var torskarna fortfaran- de vid god vigor. Vidare gjordes langtidsférsék med strémming, som stingdes in i ett rektangulart spant nat, vars blysin- ken lag pa bottnen och vars korkfléten lag i ytan. Detta s. k. »stang» hade en omkrets av ca 30 m. Det ena héenet av stdnget lag endast ndgon meter fran den utanfér beldgna elektroden, medan det diagonalt motstaende hornet lig pa ca ro m avstand fran denna. Nagra hundra stroémmingar slapptes in i ett sting och fick gi dar i to dagar med strémmen sluten. Elektroden var da katod. Hela tiden gick strémming- en valsamlad i ett stim runt stanget till synes utan att paverkas av det elektriska falter. Tempordra férsdk med fisk invid elektroderna Buren med nagot slag av ovanstdende fisksorter placerades vid strémlést tillstand pa varierande av- stand fran elektroden. Strémmens slutning och bryt- ning beordrades via radio. Lag buren_r a 1,5 m fran elektroden, nar den var anod, si kunde man hos fis- karna i sjalva strémslutningsdgonblicket observera en mycket kraftig reaktion — de sprattlade haftigt till, orienterade sig huvudsakligen i spanningsfallets rikt- ning samt drogs hastigt mot anoden. P4 vagen dit vin- de de buken eller sidan upp, ffot till ytan och blev pa vagen eller invid elektroden fullstindigt beddvade. Nar strémimen bréts, kvicknade fiskarna till nastan omedelbart och sam omkring i buren, som om ingenting hant. Man kunde dven f8 liv i dem, om buren avligs- nades nagra meter fran elektroden. Vidare iakttogs, att de stérsta fiskarna bedévades fortast och vak- nade sist till liv i jamfdrelse med de mindre, sakerli- gen beroende pa att de var utsatta fir det stérsta spanningsfallet. Gjordes samma férsék med buren pa ca 2 m av- stand fran elektroden, var reaktionen mycket mindre och uteblev i flesta fall helt. Vid 3 m avstand kunde ingen reaktion observeras. TT Motsvarande férsék gjordes med elektroden som ka- tod. Reaktionerna i och fér sig var desamma som vid anoden, men den visentliga skillnaden var, att fiskar- na har drevs bort frdn katoden och samlades i det 85 tran elektroden mest aviagsna hérnet, dar de slutli- gen bedévades. Vid korttidsférséken med strémming hingdes en bunt av fem magnetitelektroder i stangets mitt. Vid stromldst tillstand gick strémmingen som vanligt i stim huvudsakligen utmed stingets ena sida 4 a 5 m fran elektroden. Nar man slét strémmen med elektro- den som anod, kunde man inte marka nagon reaktion hos huvuddelen av stimmet. Nagra av fiskarna kom dock da och d& ur kursen, och om de kom pa ca 2 m avstand fran elektroden, »stelnade» de och drogs mot denna, dar de upprepade ganger »studsade» mot elektroden med huvuder. Till slur bedévades de dock fullstandigt och flét omkring med buken upp. Sa smaningom samlades allt flera strémmingar runt elek- troden fér att efter nadgra minuter uppga till ert tju- gotal. Nar s& strémmen brits, kvicknade fiskarna omedelbart till igen och sam sin vag. Om bedévningen tillats vara langre tid an ca 4 minuter, kunde fiskarna dock ej hamta sig lingre utan avied. Det bdr obser- veras, att under hela férsdkstiden huvuddelen av stim- met fullkomligt oberdrt gick fram och tillbaka utmed stdngets ena sida. Vid samma férsék men med elektroden som katod kunde ingen reaktion alls mirkas hos fiskarna. Aven nu kom nagra ur kursen, men de undvek elektrodens narmaste omgivning. Ej heller i sjailva_ strémslut- nings- eller brytningségonblicket kunde nagon paver- kan observeras. Kontakt hélls med yrkesfiskarena Med hansyn till det yrkesmissiga fisket var tid- punkten fér undersdkningarna ej den basta, meg kon- takt hélls dock med nagra fiskare, som lade skdtkrok efter strémming i Lindédjupet. Under midsommarvec- TemporGra fSrsék med braxen vid katoden. Fiskarna har drivits bort fran katoden. kan erhGll de for arstiden ovanligt goda fangster och fiskarena ville nog satta detta i samband med strém- Sverféringen. Fangsternas storlek avtog dock sedan snabbt och fisket installdes. Efterit var man dverens om att strémmen nog ej haft nagon inverkan pa fisker. De hydrografiska férhdllandena studeras Vattnets syre- och salthalt samt vitejonkoncentra- tion bestamdes fére, under och efter fdrséker. Den enda férindring, som har kunde iakttagas och som kunde tillskrivas stréméverféringen, lg i vatejonkon- centrationen i Fartarmen, som sjonk fran 8,31 till 7,90 under den tid elektroden har var anod. Denna sank- ning ar dock obetydlig, om man betinker, att man har hade en relative begransad vattenmassa, medan i verk- ligheten elektroderna kommer att ligga i fritt vatten. Resultat Av ovanstaende framgir, att man med lampliga skyddsatgirder med stérsta sannolikhet kan undvika skador pa havsfaunan vid en stréméverféring med vattnet som den ena ledaren. De skador, som uppstod pa bottenfaunan vid férséket, kan med lamplig elek- trodplacering och lampligt elektrodmaterial vid en 86 verklig dverféring helt undvikas. Ej heller behéver man befara, att fiskarna tar skada invid elektroder- na, om dessa inhagnas med ett nat, som hindrar fis- ken att komma i elektrodernas omedelbara narhet. I sin redogérelse Over frsdken anser ocksa Fiskeristy- relsen, att ovanndmnda fordringar 4r tillrickliga med hansyn till havsfaunans bestand. Vid en verklig kraft- dvertéring bér dessutom de lokala fragor, som sam- manhianger med sjilva kabelns strackning och elektro- dernas placering, diskuteras med fiskerimyndigheterna pa platsen. 125346. Nordisk Rotogravyr, Stockholm 19°C ZUSAMMENFASSUNG . LFS Januar 1979 LFS 560a 1 Beeinf lussungsfragen Dieser Bericht geht auf die zu erwartende Beeinflussung von Nachrichtenkabeln und Schiffskompassen durch die HGU- Kabeln ein und gibt quantitative Schdtzwerte. 87 560a | LFS LFS Januar 1979 Information BEEINFLUSSUNG VON NACHRICHTENKABELN BEEINFLUSSUNG VON SCHIFFSKOMPASSEN eo fee) ea N n H 8 H 3 Ww & n 2 q | 5 Visv Wjope B pm vebunwunisog oF -® L Be a nyon see: pou |B1puo} coool 9'E , ; Pama ameivonioms pes g C 4n0 jnoyIIM Paido> eq jou = = = a ASEA Information LFS Januar 1979 LFS 560a 3 BEEINFLUSSUNG VON NACHRICHTENKABELN Eine genauere Abschaétzung der durch den HGU-Betrieb zu erwartenden Beeinflussung erfordert die Kenntnis sowohl der charakteristischen Eigenschaften der HGU-Kabeln, als auch der Nachrichtenkabeln. < $ 2 < ‘S 3 3 6 3 3 3 2 3 ¢ g ? $ é = 3 3 3 ~ thereot Contra- purpose, ASEA horized mm, and the conten proseculed parted to a third party nor be unaut| be jor an vention will This document must not be copied without our @rrt x 3 376 al Me} Ss a Grundsdtzlich kann festgestellt werden, dass die Oberwellen zum gréssten Teil im Kabelmantel zuriickfliessen und der restliche Anteil dann durch das Seewasser sehr nahe dem Kabel fliesst. Die Beeinflussung eines Nachrichtenkabels wird deshalb schon bei einem Abstand von einigen zehn Metern zwischen HGU-Kabel und Nachrichtenkabel verndchlassigbar klein. Die im Mantel eines Nachricghten-Kabels induzierte Langs- spannung lasst sich-z.B. mit Hilfe der Gleichung 3.73) 5 Seite 229, in Ref. (1] berechnen: Fiir verschiedene Abstadnde a zwischen parallelen Kabeln erhalt man: a= 5m 1.13 V/km, A ? 10 m 0.45 "= 20 m O52) N= 40 a 0.008 "- Die Werte gelten fiir eine Stromoberwelle mit der Frequenz 1000 Hz und fiir ein Leistungskabel ohne Mantel. Fiir héhere Frequenzen werden obige Werte wohl héher, gleichzeitig jedoch werden die Oberwellenstréme niedriger. Fiir die 24. Oberwelle (1200 Hz) wird der Strom etwa 4 A, wodurch folgende Langsspannungen bei den verschiedenen Abstanden induziert werden: 4.5; 1.8; 0.5 und 0.032 V/km. Welche Stérungen diese Langsspannungen an dem Nachrich- tenkabel bewirken, hdngt dann ausschliesslich von den Eigenschaften dieses Kabel ab. Allgemein gilt, dass die induzierten Spannungen stark reduzier werden, wenn das Leistungskabel mit einem Mantel versehen ist. Normalerweise sind ftir das Nachrichtenkabel keine St6rungen zu befiirchten, wenn der Abstand zum HGU-Kabel mindestens 50 m betrdgt. Wenn die Kabeln ganz nahe beisammen liegen, wie es bei Kreuzungen der Fall sein kann, kénnen erhebliche Langs- spannungen induziert werden. Kabelkreuzungen mit kleineren Winkeln als 20-25° sollten deshalb vermieden werden. 89 ASEA BEEINFLUSSUNG VON SCHI. nor be s thereot Contra- whout our rd party content let KSta” unauthorized prosecuted. be 3 2 & = 2 3 = 3: pe vention will g 2 zt a®@ Allgemein sollte eine langere Parallelfiihrung von HGU-Kabel und Nachrichtenkabel vermieden werden, vor allem wenn der Abstand zwischen den Kabeln geringer als 50-100 m ist. Beziiglich der hier skizzierten Beeinflussungsverhdltnisse schlagen wir ein ndheres Studium der aktuellen Falle wahrend des Projektierungsstadium vor. FFSKOMPASSEN Die Beeinflussung von Schiffskompassen durch ein Gleich- ] » Seite 280, eingehend behandelt. Mit Hilfe der dort gegebenen Gleichungen kann der akkumulierte Positionsfehler bei Passage des HGU-Kabels berechnet werden. Auch die Berechnung des kritischen Passagewinkels, bei welchem ein Schiff vom Kabelfeld lasst sich verhdltnissmdssig einfach durchfiihren. stromkabel wird in Die Nummern der im Folgenden angegebenen Gleichungen, beziehen sich auf oben angefiihrtes Buch. Die Gesamtabweichung eines Schiffes, das die Kabeltrasse passiert, wird durch Gleichung 15.58 ausgedriickt: Ys 1 Information LFS Januar 1979 LFS 560a eingefangen" werden kann, sin ? Hierbei bezeichnet I yl - oe +cos ? den die die den Gleichstrom (A) erdmagnetische Feldstadrke (A/m) Meerestiefe (m) Winkel zwischen Kabeltrasse und Schiffskurs ASEA Information LFS Januar 1979 LFS 560a Mer delse hdrav ¢ < € 3 ‘obehdrigen ‘as med siéd av gal inde lag. ASEA Ss 3 € 3 = 2 € € 3 2. beivr Contra- d pa unauthorized purpose. be ‘prosecuted. ASEA Fiir EPOS muss angenommen werden, dass das Kabel parallel zum Magnetfeld der Erde verlegt wird, was die ungiinstigsten Verhdltnisse ergibt. Diese Voraussetzung gilt auch fiir die vereinfachte Gleichung. Fiir die Passage winkelrecht zur Kabeltrasse, d.h. fiir f = 90°, ergibt sich _ Fir l= 760A H, = 16 A/m (angenommener Wert) wird / Y = 23.8 0 Fir p< 90° nimmt der Fehler langsam zu. Der maximale Kurs- fehler wird ? ° I tao cm Zea ele iit Damit wird fiir t = 35 m (Meerestiefe entlang der Kabeltrasse) Wena In einem Abstand von 100 m vom Kabel sinkt der Fehler bereits auf 1.3°. Ein Schiff, das einen Kurs entlang der Kabeltrasse steuert, wird durch das Magnetfeld des Kabelstromes eine Strecke aus dem Kurs gebracht, die bei einer gesegelten Distanz von 1.7. km etwa 100 m betragt, bei 11 km etwa 200 m und fiir die ganze Kabelstrecke etwa 400 nm. 91 ASEA Information LFS Januar 1979 LFS 560a | 6 se Bestiinmungen wird gesetzlich verlolg!. ASEA s onnan eller iva: s 3 € 3 2 S 3 = € <. > <. 2 3 far 8 1 ej holler del; igen anvindas. beivras med siéd ov ras. Den obehSri Denna handlin kopier ithout our st not be copied , and th rosecuted. ASEA nauthorized purpose. Contra- ei aeeeeee be Mit zwei Kabeln, wobei angenommen wird, dass jedes 760 A iibertragt, wird der Positionsfehler ‘fiir Schiffe, die die Kabeltrasse kreuzen, verdoppelt. Die Gesamtabweichung Y wird damit bei etwa winkelrechter Kreuzung 50 m, und zwar ziemlich unabhadngig vom Abstand zwischen den beiden Kabeln. Fiir Schiffe die nahezu parallel zu den Kabeln fahren, ergeben sich etwas andere Verhdltnisse. Nun spielt der Abstand zwischen den Kabeln und die Position des Schiffes im Verhdltnis zu den beiden Kabeln eine Rolle. Werden die Kabeln geniigend weit voneinander verlegt, ist natiirlich nur ein Kabel wirksam. Fiir den Sonderfall, dass cotg? = = wird Yoo. Das bedeutet, ° dass das Schiff durch das Kabel "eingefangen" wird und danach fiir Kreuzungswinkel gleich oder kleiner als Py der Kabeltrasse folgt. , Dieser kritische Winkel ergibt sich fiir EPOS-HGU, mit den getroffenen Annahmen, zu 12.2°. In Wirklichkeit wird dieser Winkel etwas kleiner, da die Berechnung von einem unendlich langen Kabel ausging. ; Die Gefahr fiir ein Schiff eingefangen zu werden, was zu betrdichtlichen Positionsfehlern fiihren kann, ist damit nicht von der Hand zu weisen. Diese Gefahr kann jedoch durch Verlegen des Kabels in einem Zick-Zack-Kurs, mit Winkel- abweichungen von etwa 129, verhindert werden. Die Lange des Kabels wird dadurch nur um etwa 2-3 2 vergréssert. Um zu starke mechanische Beanspruchungen am Kabel zu vermeiden, ist es ohnehin zu empfehlen, das Kabel in leichten Bogen und nicht schnurgerade zu verlegen. Q] Dr. E. Uhlmann: Power Transmission by Direct Current, (Springer Verlag, 1975). [2] ~ F. Busemann: The Magnetic Compass Error Caused by D.C. Single Core Sea Cables. Direct Current, March 1954. 92 This document must not be copied without our written permission, and the contents thereol must not be imparted to @ third party nor be vied for Denno handling f&r | vian virt medgivande kopieras. Den fir oj heller delgivas annan eller eljest obshdrigen anvandos. OvertrSdelse hdrav be- ivras med s18d av gallands log ASEA BI723.n (9472) vie Ore « ‘ony unavihorized purpose. Contravention will be prosecuted ASHA Information# Fahb Sept. 1963 | 4809 574 Experience of earth return gained from experimental investi- gations and commercial installations Replaces earlier Information with number 4809 551 periments in Sweden In the years 1943-1946 a series of experimental investigations were made in Sweden in order to study the effects of D.C. earth current. Sheng experiaiets are iene ‘bed in the CIGRE Reports Noe 134, 1946 and Noe 401, 1948 1 The distance between the electrodes varied between 50 im and 1,100 kme Existing A.C. overhead transmission lines (the three phases connected in parallel) were used to connect the electrodes. Direct currents between 20 and 330 A were used. The condit— ions at electrodes placed in the ground, far from the sea, and in the sea were studied. Potential distribution and currents in cable sheaths and railway tracks were measured and compared with the results of theoretical calculations. Some very interesting conclusions can be drawn from these measurementse The study of the potential distribution shows that the earth's crust, from the point of view of electrical conductivity, may be divided into three layerss a top layer of about 1 km, with a resistivity of about 4,000 ohm-metres, below this down to about 30 km a layer of primary rock with & resistivity of about 14,000 ohm—metres, and then at greater depths a molten mass, the resistivity of which is as low as 800 ohm=metres. These results are confirmed by other observationse The tem— perature of the earth's crust, for instance, increases by about 1°C for each 30 m, which means that the melting point of the earth is reached at a depth of about 30 kno If the distance between the electrodes is small, the current will mainly be confined to the uppermost layer, the primary rock acting as an insulator. For medium distances part of the current will pass through the inner molten mass of the earth, and for large distances most of the current will take this way. With electrodes placed in the sea very little current will enter the surrounding land. The conductivity of the sea water can be up to 70,000 times that of the primary rock below and the sea may, therefore, be regarded as a huge plate electrode. Almost all the current goes from this plate down into the molten interior of the earth, and a very small part of the current will go in over adjacent land areas following the earth's surface in the badly conducting primary rock. . It is also apparent that with a long distance between the electrodes the current distribution around an electrode is 8 NoB. Number appearing after reference to publications Fahb 2013a indicates position in List of References at end of ‘ this Information. odele hévav be eS en eavandas. Ovi ‘ennan eller eest obeho: 1d sad av gillonde log. 10 hondling f+ ej vion vait medgivende hopieros. Den Ide ej heller 3 z = ASEA The Gotland Scheme Fahb 2013b Information Fahb Sept. 1963 4809 574 Reg. 735 quite independent of the route of the D.C. transmission line, and is determined by the resistivity conditions only. The risk of corrosion of underground cables and other nefayiic structures has been treated to quite an extent by Busck | With an electrode placed on land and far from the sea and carrying 1000 A and with reasonable assumptions regarding resistivity of ground (1000 ohm-metres) and cable size and resistance (radius of cable 3 om, resistance of armour 0.1 ohm per kn), @ minimum distance of 6 km between electrode and cable will be reqaszed for a leakage current on the cable surface of 1 pA/om? ° In order to Jat te the leakage cur— rent on the cable surface to 0.1 ALA, the distance between the electrode and the cable has to -— increased to approxim= ately 18 kn. It has also been established by the calculations and also by the tests that if the electrode is placed in, or in the vicinity of, the sea the permissible distance between cable and electrode can be considerably reduced, due to the fact that most of the current will enter the sea as mentioned previously. With the same assumptions as above and a resist~- ivity of the sea of 0.2 ohm-metre, the of 1 nal os approxim= ately 4 km will give a leakage current of 1 pab/' om2. = Permanent earth return has been successfully a 3 Gotland transmission since its commission in 1954 a) *10) 11) This scheme transmits 20 MW at 100 kV over a distance ue about 100 km by a submarine cable. The current is 200 4. The decision to use earth return was based on the experiments referred to above and calculations taking into account the conditions in this particular case. The direction of current through the earth is always the same in this scheme - from the mainland electrode at Vastervik to the Gotland electrode. The direction of power is reversed by reversal of the cable polarity.- With this arrangement it has been sufficient to build one positive electrode. In a double conducter mid-point earth system where the sarth is to be used in the case of failure of one side, the direction of current through the earth may be either way, depending on the side which is shut down. Thus both electrodes must be con- structed as positive electrodes. Corrosion only oceurs on the positive electrode, and consequently the two Gotland elec- trodes are of completely different design. The negative elec- trode on the Gotland side consists of a smooth copper conductoz laid on the sea bed at a distance of 350 m from the shore. The positive mainland electrode consists of 9 number of parallel- connected magnetite rods placed in an excavated basin on the sea—shore. A detailed account of the earth return arrangements in the Gotland transmission is presented in a CIGRE report published 94 ( ASEA Fahb 2013c ~ Information Fahb Sept. 1963 4809 574 | 3 Reg. 735 in 1954: "The Gotland H.V.D.C. Transmission and the Underlying Development Work", by B. G. Rathsman and U. Lamm 9/. The location of the electrode, in relation to cables exposed to corrosion, including the D.C. power cable and an already existing telephone cable which followed approximately the same route as the D.C. cable, was determined by calculations. It was found that with a distance of 7 km between the cable and the electrode the maximum leakage current in the cable would be 0.2,14/om? at a maximum electrode current of 200 A. A leakage current of 0.1 pA/om2 would have required a distance of 9 kn. The distance actually chosen is about 10 km. It should be noted that this refers to the Baltic Sea where the salinity of the water is very low (0.7 ohm-metres). The con- ditions are more favourable when the salinity is higher. The submarine telephone cable is located at a somewhat greater distance from the electrode than the power cable and is, there- fore, less exposed to corrosion than the latter cable. After the direct current cable had been laid potential measure— ments were made to determine the risk of corrosion. The measurements showed that the iron armouring and lead sheath were at a potential of about 1.0 volt (relatively to a copper/ coppersulphate electrode). Since iron will not corrode if the negative potential to earth is at least -0.85 V (-0.55 V for lead) it follows that the cable is protected against corrosion as long as the galvanized layer on the iron armour ing is intact. The difference between the potential in a currentless and a current-carrying cable is insignificant (0.005 V), and consequently the leakage current from the sea electrodes is inappreciable so that the galvanized layer is very little exposed to corrosion. Experiments for the possible protection of the galvanized layer of the armouring have been carried out by electrical drainage on the Gotland side. The test showed that a drain- age current of a few amperes suffices to eliminate the risk of corrosion entirely. Up to the present, however, the risk of corrosion is regarded as so slight that no measures for drainage have been taken. Check measurements of the cable potential are carried out about once 4 year. It is apparent from the foregoing that the operation of the earth return system applied in the Gotland transmission has been very successful. With a distance between electrode and cable chosen on the basis of theoretical calculations, the risk of corrosion has been completely eliminated. Methods of protecting the cable sheath and armouring - cathodic pro- ~- tection and electrical drainage - have been studied but no measures have been undertaken so far. It has been estab- lished that there is no risk of corrosion as long as the gal- vanization of the cable armouring is in good condition. Neither have there been any reports indicating corrosion of 95 ~~ §3 2 medgivonde hopievas. Den lor @ heller vigen anviindas. Overiadelre haray be: ivias med sod av gallande log ASEA Thu document must aot be copied without our wii Contents thereof must aot be imparted 10 @ third ony unauthorized purpose Coatrovenon will be pr Denna hondliay delgivos annan el (954) vet @urd« “N 8 a < € ASEA Experience in Japan Fahb 2013d Information Fahb Sept. 1963 | 4809 574 4 Reg. 735 ‘ other underground and submarine installations in the vicinity of the electrodes. xperience in the U.S.S.R. Corrosion of underground constructions owing to earth currents has been studied in the H.V.D.C. transmission Kashira-Moscow. The tests are described in Electricheskie Stantsii No. 1, 1956 6) 7). Unfortunately, the theoretical investigation made by the Russians was very approximate and their experimental investi- gations were carried out with an unrealistically small dist- ance between the electrode and the cable. A study of the Russian investigations in view of later calculations (Rusck 17) disclosed that the Russian results are far too pessimistic. Experimental drainage of cables and underground structures exposed to earth currents has been carried out and has proved to be a very efficient protection against corrosion. In Japan direct current is used for electric railways. Nor= mally the earth is used as a return circuit but in some places where the railway runs along the coast the sea is used for this purpose. In a paper submitted to CIGRE Study Committee No 10 in 1955 5), K. Hoshino describes five installations for sea return and summarizes the operation experience gained. The maximum current through the sea is 300, 800, 900, 1,000 and 1,200 A in the five plants. The oldest installation with a@ maximum current of 1,000 A has been in operation since 1941. By means of the sea return system the major part of the load current in the railway tracks is drawn into the sea. As a result the leakege currents from the tracks to the earth dimin- ish and consequently the corrosion of the tracks is prevented. At the same time the corrosion of underground metal objects is decreased as a result of the reduction of leakage current. Even where the rail is connected, not directly to the sea but +o an earth electrode in a river situated within the tidal area 1 or 2 km up from the coast, many cases of decreased corrosion of underground cables, pipes and rails have been observed, but hardly any of increased corrosion. The only cases of an increased tendency of corrosion observed in connection with the Japanese installations are on submarine cables situated 400 m from an electrode and on propellers of a- ship which had been lying at anchor for a long time at a dist- ance of only 10 m from an electrode. Disregarding these exceptional cases, the Japanese paper states that the experienc of sea return has been entirely satisfactory. 96 ui) Ours (954) “ 8 3 < < ASEA Fahb 2013e List of References 1. 6. 8. 10. 11. 12. 13. Information Fahb Sept. 1963 Reg. 735 5 Iundholm, 2., Séderbaum, C.E., Beckius, I., and Bockman, H.: "D.C. Transmission with Return Current Through Earth", CIGEE Report No. 401, 1948. lundholm, 2.: "Direct Current Through Earth", CIGRE Report No. 134, 1946. lundholm, R.: "Return Current Through the Earth for H.V.D.C. Transmission", Direct Current, 1953, Vol. 1, Noe 4, ppe79-96. Lidén, I., Svidén, S., and Uhlmann, 8.:"The Gotland D.C. Links The Layout of the Plant". Part I, Direct Current, 1954, Vol. 2, No. 1, pp- 2-7. Part II, Direct Current, 1954, Vol. 2, No. 2, ppe 34-39. Kyuhei, Hoshino: "Examples of Sea Return Circuit for Railways in Japan", Railway Technical Research Institute, Japanese National Railways. Paper submitted to CICRE Study Committee No. 10, 1958. Bagenov, S.A., Nocolsky, K.K., and Michailov, M.Is: "Corrosior of Underground Metal Constructions in Earth-Return D.C. Trans- mission", Electricheskie Stantsii, 1956, No. 1. English translation: CIGRE Study Committee No. 10. Bagenov, S.A., Pimenov, V.P., and Sonin, M.R.: "“Investigatior of Some Problems Concerning the Earth-Return H.V.D.C. Trans~ mission System on the Experimental H.V.D.C. Power Transmissior line Kashira-Moscow", Electricheskie Stantsii (1959):9, pp. 54-59, 7 ref., Internal ASEA English translation. Pettersson, G.A., Ahlgren, L. and Forsell, H.: "Telephone Interference and other Effects caused by the Gotland H.V.D.C. Transmission", CIGRE Report No. 324, 1958. Rathsman, B.G. and Lamm, A.U.: "The Gotland H.V.D.C. Transmis- sion and the Underlying Development Work", CIGRE, 1954. Lane, F.J. and Smedsfelt, S.: "Report on the Work of Study Committee No. 10, D.C. Transmission at B.H.V.", CIGRE Report No. 417, 1960. Rathsman, B.G. and Svidén, S.: "The Gotland H.V.D.C. Trans- mission Link", Blue-White Series 15 E, Swedish State Power Board. Sayers, D.P., Laborde, M.E. and Lane, F.J.: "The Possibilitie of a Cross—Channel Power Link Between the British and French™ Supply Systems", Proceedings I.E.B., 1954, 101, Part I, pp. 284 = 308. Gosland, L.: "Phenomenon Associated with H.V.D.C. Transmissio lecture at Manchester College of Science and Technology, 1953 Direct Current, 1953, Vol. 1, No. 7, pe 166. 97 Viet Ones ASEA Fahb 2013f 146 15. 16. 17: 18. Information Fahb Sept. 1963 | 4809 574 | 6 Reg. 735 Romanoff, M.: "Underground Corrosion", United States Depart—- ment of Commerce, National Bureau of Standards Circular 579, April 1957. Vivian, A.C. and Gerrard, J.S.: "Cathodic Protection: Some Basic Considerations", Direct Current, 1955, Vol. 2, No. 6, pe 138. De Brouwer, 2.: "Cathodic Protection of Buried Metallic Structures", CIGRE Report No. 205, 1948. Rusck, S.: "H.V.D.C. Power Transmission, Problems Relating to Earth Return", Direct Current, 1962, Vol. 7, No. 11, Pp. 290 = 298, 300. Ollendorf, F.: "Erdstréme" (Book), Berlin 1928. 98 ASEA Information LFA November 1976 |LFA 133a Reg. 0611, 7350 jegen die- gt. ASEA verfol 4) ~ Although e.g. touching the insulated fence as discussed above gives a shock which can be considered annoying, a large and comprehensive program of research has shown the true danger 2t a.c. being minimal. For d.c. the short-circuit current will te significantly less, and consequently also the risk will be less. The effect on man by shock-currents at touching an insulated ~ object as well as steady-state currents are thoroughly dealt with in ref. 1. It is evident that the effects of direct current on man is far less than from alternating current, e.g. she let- go current (the maximum current at which a human holding an energized conductor can control his muscles enough to release it) for man is 16 mA for a.c. and 76 mA for d.c. ELECTRIC AND MAGNETIC FIELD EFFECTS igivande an eller rfadelse hdrav . ASEA vton vart med ler delgivas anni ter of igen anvSndas. Rr ej he s13d av gdllonde Denna hondlin, 4 EXPERI 00M D.C. ENCS 2F and the contents thereof ; ot This document must not be copied without our The French periodic Revue Générale d'Electricité has a special” issue July 1976/completely devoted to the biological effects by electric and magnetic fields (ref. 3). The paper apart from publishing 2 number of special articles of the subjects also gives a broad bibliography of the literature within this subject. The paper is almost entirely concentrated to the effects fron alternating fields. } The conclusion of the articles of the paper as well as the reports listed in the bibliography, based on a considerable volume of observations and research, is that living org2nisrs are aware of the physical existance of the field and they detect its presence, however, without the slightest risk. As an exception from this general statement some Russian scien- tists have reported illness of high-voltage substation workers - (e.g. ref. 9). Up to now no similar problems have been reported in the rest of the world in spite'of the comprehensive research which has been performed. SCHEMES IN OPERATION So far no side-effects on man from overhead d.c. transmissions have been reported. 99 os Y The Anodic Earth &, 4F Yr r2e Electrode Se Konti-Skan E.Y.D.C. Link \ By E. Andersen and N. 2. Néilsen* os Introduction N the Konti-Skan d.c. transmission link the earth is used as the current return path, as this proved to ’ be technically possible and economically advan- tageous. The construction of the electrode station is the main technical problem when the earth has to be used as return. Conditions at the two electrodes, the positive and the negative, are, however, widely different. At the positive electrode, the anode, special provision must be made to avoid excessive loss of material by elec- trolytic corrosion. At the negative electrode, the cathode, on the other hand, no corrosion problem arises. At an carly stage of the planning, it was decided that the current in the sea cables should always flow from the east to the west, i.e. from Sweden to Denmark. This means that the magnetic field from the current is always in the same direction as the natural magnetism of the earth, thus causing the least inconvenience to shipping. The reversal of power transmission will have to be effected by reversal of polarity rather than reversal of the current direction. With this arrangement the electrode on the Danish side is always the anode and that on the Swedish side always the cathode. The latter station could therefore be very simple, and it consists, as on the Gotland link, of about 300 metres of non-insulated copper cable, laid on the sea bed. Construction problems were thus limited to the Danish electrode station. Initial considerations It was from the outset obvious that the station ought to be placed at the coast in order to reduce the corrosion problem. : A site by the sea would reduce the area of land which could be affected by corrosion, and theoretical calculations also showed! that the main part of the current would go towards the better-conducting sea water. A site at the coast of Kattegat was chosen in preference to one at the Limfjord, near the converter stution in Vester Hassing (see Figure 1). This latter site would have given a shorter overhead line to the station, but with the ‘ Limfjord being very narrow, corrosion problems would have been more likely there. Measurements at and near the station now built at Kattegat may, however, show that the station at a later stage could be moved to the Limfjord without giving rise to corrosion problems. *Mr. Andersen and Mr. M. R. Nielsen are with ELSAM, The Jutland-Funen Electricity Consortium, Denmark. 54 100 The choice of site at Kattegat was affected by the decision to install from the outset both conductors on the double-circuit d.c. line from Vester Hassing to its ter- mination at Stensnes, which meant that one of the con- ‘ductors could then be used as electrode line. About 8 km south of Stensnes a short length (3 km) of lightly insulated line was built from a tee-off on the main line to the coast at Sora, a fairly isolated spot, remote from built-up areas, harbours, cables, etc. The site at Sora consists of 1.5 acres of marshy land. The length along the coast is about 137.1 metres and the depth about 45.7 metres. . Here the water is very shallow far into the sea (see Figure 2). At low tide the water recedes as much as 400 metres. Due regard had to be given to fairly high tides. At least once a year the water is expected to rise | metre above normal level, so that the whole site will be submerged (see Figure 3). Regarding the positioning of the electrodes we had to consider whether they should be placed on the site itself or in the sea, which would have obvious advantages. . This latter alternative had, however, to be abandoned because the risk of damage from ice in hard winters was considered to be too great. We therefore decided to con- centrate on designing a station with the electrodes situated on land, inside the normal coastline. Design of the electrode station The most obvious solution was to excavate a big pool and have the electrodes suspended in water from wooden frames. This arrangement is used at the anodic station at Vistervik on the Gotland link. The walls of the pool are here made of rather large boulders which gives pienty of water-filled cavities. Water can then easily penetrate the pool and the natural changes in sea level and the waves will give a washing out of the pool. For Konti-Skan a pool of 60 by 16 metres would have been necessary. Due to the rather special conditions of the chosen site (wide areas of shallow water) natural washing out of a pool would have been quite inadequate, and it would therefore have been necessary to pump seawater to the ool. : Tests in the moist soil indicated that water in a pool without pumping would probably have a salinity con- siderably smaller than the seawater, due to underground fresh water flowing to the pool. Pumping would therefore - also have been necessary in order to increase the conduc- tivity of the water around the electrodes. Having realised that a pumping arrangement was un- avoidable we tried to find a simpler and more economical alternative to a pool. This led us to consider an arrange- ment with a number of pipes or wells with an electrode suspended in each weil. From a system of plastic pipes it would be easy to supply each well with the necessary amount of seawater. If we were to continue along those lines the main problems would be: (1) To find a suitable material for the wells which would not corrode due to the electrolytic products formed by electrolysis of salt water. (2) To ensure a reasonable division of the d.c. current (max. 1,050A) among a suitable number of electrodes. May 1966 DIRECT CURRENT Tests In order to clarify these main problems a series of tests were carried out, and after some consideration and advice from chemical engineers we decided to try hard poly- vinyichloride (PVC) for the weils. Fortunately PVC pipes have been used by well drillers for some years for the sandfilters placed at the bottom ofa weil and from which the water is pumped out. These pipes were available with an inside diameter of 230 mm, a wail thickness of 10 mm and in lengths of 6 metres, with the dimension and number of slits we required. For the tests two wells of PVC piping each 3 metres deep were made at the beach in Kolding Fjord near Skerbak Power Station, and the following equipment was provided: 2 graphite electrodes, length 1.5 metres, diameter 75 mm, weight approximately 15 kg. 1 Welding converter for 300 A, 100 V, d.c. 1 water pump to give a suitabie circulation of salt water ~ in the wells. A series of tests were then carried out using the two clec- trodes as anodes and the steel constructions at the power station quay as cathode. Current per electrode The first tests were merely made in order to find the maximum current carrying capacity of the electrode placed in one of these weils. We found that it would carry somewhat more than 50 to 60 A without any problems arising. The salt water flow could without difficulty be limited to as little as 0.2 litres per second per well. This gave suitable flushing and very little rise in temperature (less than 0.5 deg. C) in the well. By weighing the electrodes after they had each carried 50 A for about 2 months (approximately 70,000 Ah) we found that the electrode material was disappearing at the rate of about 5 grams per 1,000 Ah. The reason for this low figure is undoubtedly that the electrolytic products (chlorine and oxygen) are rinsed out by the water circulation. This meant that the graphite electrodes would have a life of more than ten years at approximately 200,000 Ah per year per well, which was a very satisfying result. The necessary number of weils was thus 20 to 25 (maximum current 1,050 A). Current sharing We then investigated how the current divided itself between the two electrodes (weils) connected in parallel. This test also gave very satisfying results, with a very even distribution of the current between the two electrodes. The deviation from the ideal division was as little as +10 per cent, and this in spite of the fact that one well was placed very close to the beach (approximately 2 metres) and the other about 10 metres away. The subsoil in the test area consisted of sand mixed with clay and remains of vegetation. To get'an impression of the current sharing between a greater number of parallel electrode weils we made a laboratory test in which an electrode station of twenty wells was set up on a linear scale. The electrode wells were simulated by thin copper wires fixed to a piece of wood and placed in a straight line. These electrodes were then sub- merged in a tub of salt water. The current sharing between these twenty electrodes was found to be completely acceptable. _ We knew in advance that there would be a strong mutual potential influence between the twenty electrodes. The outer electrodes would have a tendency to carry the larger Ficure | MAP OF THE NORTHERN PART OF FATTEGAT WITH THE KONTI-S” AN D.C.-TRANSMISSION SCHEME. CIRCUIT ARRANGEMENT FOR THE FIRST STAGE OF THE SCHEME 0 50 DIRECT CURRENT May 1966 101 KATTEGAT ® Converter siation | {| |_L <= Stenkullen tte “7: ‘y Gothenburg *e @.c. overhead line with two fully insulated conductors —-dc. submarine cable for 250 BV ---—— Low insulated overhead line and cable OC3i3-! 55 Lb farmhouse +20m +m Deep water +10m 0 300 700 —+00 once 2 year —+075 7 times 2 year Main pipe for sit wssier Supply: ‘ Graphile electrode Current- permeable zone f 0 f 2 Metres | oh, 102 Sea water level to be expected —+1/52(flood observed 1893) SECTION OF THE COAST AT SORA. NOTE THAT THE VERTICAL SCALE {S —+h25 once in 5 years — +0:50 40 times 2 year 700 100 «0 $00 Ficure 2 (above) 10 TIMES BIGGER THAN THE HORIZONTAL Ficure 3 (left) CROSS-SECTION OF AN ELECTRODE WELL share of the current. We tried to anticipate this tendency by placing the outer wells closer together than those in the middle. After these investigations we felt sure that we could get an acceptable current sharing between twenty to 25 weils placed in a row near the beach. Failure of the water circulation In view of the possibility of failure of the salt water circulation it was important to investigate what would happen to the electrode wells under such circumsiances, the main problems being the rise in temperature and corrosion. Without water circulation the temperature in the test wells reached an almost constant value of about 50 deg. C in a few days, i.e. a temperature rise of about 40 deg. C. These conditions were maintained for fifty days. The hot liquid containing the electrolytic products, chlorine and oxygen, corroded the graphite electrodes very rapidly. Weighing of the electrodes showed that the graphite was dissolved at the rate of approximately 50 grams per 1,000 Ah, i.e. ten times as fast as under normal conditions. Furthermore the corrosion now appeared to be much more uneven. In the short time available (8 to 12 months) it was much more difficult to determine the rate of corrosion of the PVC well material. In order to get at least some indication of the chemical reaction on the PVC material, a piece was cut up and placed in a sample of the liquid from the test well. After some months we found that the only difference in the PVC was a slight discoloration from the chlorine, but the mechanical properties were unchanged. These results were confirmed on examination of the test pipes after the conclusion of the tests. We are therefore confident that the PVC piping will prove satisfactory for many years of operation with con- tinuous water circulation. The concentration of electro- lytic products in the wells will be negligible. Earth resistance The tests with the two electrode wells also gave us some information on the probable carth resistance for the finished anode station with twenty to thirty electrodes connected in parallel. We measured an earth resistance of approximately 0.8 2 for a single electrode. As expected, the largest part i ; Ficure 4 GENERAL VIEW OF THE FINISHED ELECTRODE STATION May 1966 DIRECT CURRENT ee a me CT of the voltage drop from the electrode to infinity was found to occur within an area very close to the electrode well, 75 per cent of the voltage drop inside a 7 metres radius. The test electrodes were, as previously mentioned, found to have a current carrying capacity in excess of 50 A. At a commercial plant where great reliability is required, it is, however, necessary to have a certain safety margin and in the final design the following data for the electrode were decided upon: Electrode length: 244 cm (testlength 150cm) diameter: 100 min (test electrode 75 mm) * number of electrodes: 25, i.e. maximum current.42 A per electrode (test electrode 50 A) Due to the larger dimensions of the electrodes an earth resistance of 0.5 2 instead of the 0.8 2 for the test elec- trode, was to be expected. The earth resistance R, for a compound electrode system consisting of 1 electrodes in parallel is, because of the mutual influence, not !/n of a single electrode resistance Ry, but a factor p bigger, i.e. ~ Ry = R= +P At site the wells were to be placed in a row along the beach at 5 metres interval, giving an influence factor p of approximately 1.6. The expected resulting earth resistance should then be 0S een 5 1.6=0.032 2 At the Swedish side the electrode arrangement was to be made up of approximately 300 metres, 600 mm? bare copper cable laid on the sea bed. The earth resistance of this electrode was expected to be so small that the resist- ance of the copper cable itself-would not be without significance in the computation. The resulting earth resistance was expected to be approximately 0.02 42. The total resistance for the current path through ground would thus be about 0.052 2. Number of wells Before the number of electrode wells was finally decided “upon we looked at the economics in adding to the number (25) which were considered adequate from a current carrying point of view. By adding to the number of electrodes, the earth resist- ance and consequently the losses would be reduced. We found that the capitalised saving in adding a well was only about 1,400 Danish Kronor against the extra cost of about 3,000 Danish Kronor per well: an increase in the number .of wells was therefore not economically justified. Following the commissioning of the electrode station the assumptions on which our calculations had been made have been verified. Description of the finished station The electrode station lies at the coast of Vendsyssel about | km north east of the village of Sora. The surround- ing area is extremely flat. The sketch on Figure 2 shows a profile of the coastline. The nearest buildings area summer bungalow 600 metres from the coast and a couple of farms approximately 800 metres away. The subsoil at the site consists of about 1.4 metres of sand, with blue clay underneath. Drilling showed that clay is found down to at least 44 metres. The stratum of clay was an unpleasant surprise as it would make the Ficure 5 LAYOUT OF THE ELECTRODE-STATION ‘see TT cere ere fren ermmeeen een reer cr aa La sr ree erm rm eee OT se Electrode-line, 10mm? ACSR jh25mm ? pyc insulated copper ili cable. One for each weil. 1| Number 16 shown only 200008 1% pa = Electrode wells i Symbols i ‘3 Dam | a a) . | tees Oulflow ditch with Salt water wells in | a ihe ba A sea- boltom | | \ _ Pv suclion pipes for f0 0 10 20 30 40 50 ee andl . dented intel ienibnnnitetelnnnet ——— —— ressure pipes tor Meires salt elon = 58 103 0¢313-5 May 1966 DIRECT CURRENT ny omen Sea planned sca water pumping from wells drilled in the sea bed more difficult than was at first anticipated. The clectrode conductor, 910 mm? ACSR is connected to a copper busbar | metre long at the stayed terminal- tower (Figure 4) and 25 plastic-insulated copper cables, each 25 mm? in section, connect the electrodes to the busbar. The length of cable varies from 18 to 78 metres. In a water proof bakelite box at each electrode the cables are connected to neoprene-insulated cables with which the graphite electrodes are suspended (Figure 3). The 25 electrode wells are placed in a row along the beach, approximatciy 20 metres inside the coastline (Figures 5 and 6). Wells No. 8 and 18 are placed at 5 metre intervals. The distance between weils is decreased towards the ends, down to only 3 metres between wells | and 2 and wells 24 and 25. This arrangement does, as previously men- tioned, reduce the tendency for the outer wells to carry a disproportionaily large part of the current. The current through the outer weils is further reduced by the much longer length of cable necessary for the outer wells. This added resistance, up to 0.04 2 for 60 metres, with 25 mm? cable, is perceptible compared to the earth resistance of the electrode itscif. In the next section the division of * current actually obtained between the wells will be dis- cussed. The weil itself consists of a 6 metre-long PVC pipe closed at the bottom with an oak plug. At the bottom of the well there is a smaller inlet pipe for sea water. The water level in the well is raised by pumping until it reaches the discharge pipe at the top. In this way a pressure of an approximately 50 ¢ n (water column) is established, so that salt water will constantly drain through slits in the weil wall into the surrounding earth. The natural draining is 10-20 per cent of the water pumped in. Without this percolation of salt water the electrode would have a bigger earth resistance as the ground water surrounding the wells is much less salty than the water pumped in. The slits in the pipe wall cover 16 per cent of the wail. The slit-zone is approximately 2.8 metres, i.e. a total area of slits of 3,500 cm? per weil giving a current density in the slits of 10 to 15 metres A/cm?. The length of the graphite electrode is 2.44 metres and the diameter 100 mm. The weight of the electrode is about 38 kg, including 5 metres supply cable. The current density at the electrode surface is approximately 5 mA/cm? for a total current of 1.000 A. The salt water for the electrode wells is brought up from wells in the sea bed approximately 25 metres outside the coastline. A seifpriming centrifugal pump is used. The pump is placed about 1.5 metre above normal sea level to avoid it being submerged even at high tide. The pump is protected against frost by an earth wall around the pump. The electrode line is, as mentioned. terminated at a stayed steel tower. The foundations for the tower and stay are 13 and 8 metres from the cicctrode wells. To avoid electrolytic corrosion of the armour rods layers of thick polyethylenfoil is piaced around the foundation block to insulate it from the surrounding ground. The tower and stay and consequently all the armour rods are earthed to two graphite electrodes placed in the ground about 16 metres from the electrode weils. The potential at this distance at 1,000 A is approximately | V less than at the tower foundation and approximately 4 V less than at the backstay foundation. A possible leakage current through the foundation insulation will therefore not give any corrosion problems. DIRECT CURRENT May 1966 104 Ficure 6 INSTALLATION OF ELECTRODE WELL PIPES. A I6 IN. DIA. STEEL-TUBE IS DRILLED 5 METRES INTO THE GROUND. AFTERWARDS THE 10 IN. WELL-PIPE IS INSERTED, THE STEEL-TUBE IS DRAWN UP AND AT THE SAME TIME FILTER SAND IS FILLED IN AROUND THE WELL-PIPE A plastic covered wire mesh has been used for the station fencing. The aim was to arrange the fence, as far as was thought practicable, along an equipotential line around the station. Figure 4 shows the chosen arrangement with semi-circles at the outer ends and straight runs in between. Even with this layout, however, potential lines will cut the fence and small insulators have therefore been inserted to divide the fence into mutually insulated sections of about 10 metres length. This reduces to a minimum the possibility of stray currents following the fence. None of the approximately thirty fence sections have been earthed as this would have been too difficult with plastic covered wire. Non-earthing is also found to be the best way to minimise voltage differences between the fence and the surrounding ground. Auxiliary power for the site is taken from an existing supply transformer about 600 metres away. It passes through a 3 by 16 mm? piastic-insulated cable. The cadle is without neutral conductor as an insulation fault would result in a d.c. current to ground through the starpoint of the transformer causing the transformer earthing con- nection to corrode very quickly. Measurements on the finished station The electrode station was finished at the beginning of May, 1965, and the complete Konti-Skan link was tested for the first time on 20th May. In the intermediate period a number of measurements were made on the earthing systems at Vester Hassing and at Sora. Ad.c. circulating current of 140 A from Vester Hassing 59 via the electrode line to Sora, with a return through earth, was obtained from a welding converter in Vester Hassing. Measurements at the electrode station confirmed that the current distribution and potential ticld was approxi- mately as predicted, which meant it should be safe to operate with currents up to 1,050 A. The measurements made with 140 A were later repeated with currents of about 1,000 A, after the complete link had been commis- sioned. In the following notes only measurements with 920 to 1,050 A are mentioned. The results quoted have throughout been converted into values corresponding to 1,000 A. The distribution of current between the 25 wells has been measured on a number of occasions. The values quojed below are rounded off and adjusted to give a total of 1,000 A. Variations in the quoted distributions have for several months been inside +! A per well. Weill Current Well Current No. (A) No. (A) 1 53 14 38 my 47 15 39 3 43 16 38 4 42 4 38 5 41 18 37 6 40 19 36 7 41 20 38 8 40 21 37 9 39 a2 36 10 40 23 35 att 39 24 39 12 40 25 44 13 40 The current distribution is shown graphically on Figure 7. The distribution curve shows very clearly the tendency for the southerly wells to carry more current than the northerly ones. This asymmetry is most likely due to the fairly even rise in the specific resistivity of the soil from well No. | to No. 25. The reason for this variation in resistivity has not been found, but the explanation could be that there is a stronger current of fresh ground water to the sea at the northern end of the site. The equipotential lines show a’similar asymmetry as mentioned later. If the soil at the site had been uniform we would have expected the following current distribution: Wells | and 25 each about 48.5 A Wells 2 and 24 each about 43 A Wells 3 to 23 each about 39 A ; Measurements of potentials and gradients serve to establish an important quality of the electrode station—its resulting earth resistance. Knowledge of the gradients is further- more a deciding factor in judging the corrosion danger for cables and pipes in the vicinity of the station. The surface potential has been investignted by meusur- ing the voltage difference between the branch-olf busbar and earth at varying distances up to 500 metres from the electrodes. Figure 8 shows the results of two series of measurements. With the special graphical representation used, the poten- tial relative to infinite neutral earth can be found by extrapolation. Extrapoiation is, however, only permissible if the increase in voltage relative to infinity is assumed to 2 follow the theoretical formula Ua ie. under the as- sumption of an even distribution of current in all direc- tions, with hemispherical equipotential planes. 60 105 Most of the gradient measurements made at points more than S00 metres from the station indicate that the increase in potential is a little less than that found by extrapolation on Figure 8. The total earth resistance for 40 V 000 A= 40 m 2. The earth resistance for a single well has been measured with an ordinary bridge as used for testing of tower earth- ing, and was found to be 0.63 2. Thus the resistance for the composed electrode and the resistance for a single well were both about 25 per cent. higher than expected. The gradients are determined by measuring the voltage difference over 20 or 100 metres. CU-CuSo, half-ceils were used at the contact point with earth. First the direc- tion of the equipotential line through the measuring point was established, and then the gradient measured at right angles to this direction. The position of the equipotential lines could be fixed with an accuracy of +5 mV, which corresponds to a radial deviation of about 2 metres at a distance of 500 metres from the station, and about 10 metres at a distance of !,500 metres. The resuits of measurements are shown on Figure 9, with the measured gradients as a function of the distance from the station. From the diagram apparent earth resistivities of 1.5 to 82.m are found. A direct deter- mination of the resistivity from the diagram is, however, only permissible with circular equipotential lines round the station. Figure 10 shows the position of potential tines at distances up to | km, evaluated from the measurements of gradients and their directions. The direction of the current in the ground is at right angles to the equipotential the station works out at approximately Ficure 7 CURRENT DISTRIBUTION FOR 25 ELECTRODES. TOTAL CURRENT |,000 4 Mal 7 60 af , 50% al \ ~— es 1 A 40 Poteet - lar mralae Py — teats ] | ] 2 i Saal ———+ | | ly Jz] * 1000 A 10+ 1 T + | } | i] | OH - - —_—_——— | i 4 7 10 6B 46 9 Te kee, Well number 0c3i3-7 May 1966 DIRECT CURRENT x South-£ast direction OQ South-West direction eee 4 | a w§B se ES FE & E § & S » SBggsh 8 8 gs § Distance r (reciprocal scale 4) ocau- Ficure 8 EVALUATION OF BRANCH-OFF BUSBAR VOLTAGE AGAINST INFINITE NEUTRAL EARTH, BASED ON MEASUREMENTS UP TO SOO METRES’ DISTANCE FROM THE STATICN line and the measurements show that the direction of the current can deviate from a radial direction. Closer to the station the accurate position of two equipotential curves around the station have been deter- mined. The inner curve, at 60 to 90 metres distance, was determined at 24 points and the outer (at 200 metres distance) at 14 points (Figure 11). The curves are cleariy asymmetrical in relation to the electrode system, with a greater distance to the equipotential lines at the north side of the station. This asymmetry is presumably closely related to the asymmetrical current distribution mentioned earlier (see Figure 5). At the site itseif the equipotential curves can be deter- mined with an accuracy of a few centimetres. Figure 12 shows the potential field for one half of the electrode system. The largest gradient of 2 V/m is found at the outer wells; in the middle of the system the maximum gradient is about | V/m. Within about 2 metres of the wells, except at the outer wells, the gradient at the surface is very small, as there is no current transmission in the top 1.5 metres of the well (see Figure 3). Discussion on corrosion danger outside the station Knowledge of the potential field around the station makes it possible to calculate the corrosion currents in metal objects. ‘cables, pipes, etc. in the ground. The corrosion currents are determined by the potential field, the form of the metal object, the extension and orientation of it relative to the station and the earth resistivity around the metal object. The calculations are rather laborious and will not be dealt with in detail here. Calculations show. for instance, that the current density in a water pipe with a inaximum length of 100 metres, about 800 metres distant from the station, will not excced DIRECT CURRENT May 1966 106 0.2 wA/em? with 1,000 A through the electrode station. The calculated current densitics of extended pipe sys- tems or cables without insulation or cathodic protection, passing the station at a distance of. for exampie, 600 metres is 3-15 zA/cm® at the point closest to the station. (The range corresponds to different diameters. wail thick- nesses and metals, for instance. iron and lead.) The current entering the cable from the surrounding soil near the station does not cause corrosion but where it leaves the cable in the more distant parts of the cable corrosion occurs. But as the “discharge’’ zone is much more extended than the “pick-up” zone, the calculated corroding currents only reach densities of 0.5-2.0 wA/cm?. It might be said that an anodic electrode station is less dangerous to nearby cabies or pipes than a cathodic station. : A continuous corroding current of about | »A/cm? would be permissible in most cases; at 1 wA/cm? a layer of 0.12 mm would corrode from an iron object in about ten years. There are in fact no uninsulated pipe- or cable-networks in the vicinity of the electrode station and private water pipes do-not exceed 100 metres in length. The corrosion risk is thus less than that indicated by the above-mentioned calculations. Furthermore, as the station is not expected to operate continuously at 1,000 A, the accumulated corrosion will be reduced in relation to the average degree of utilisation of the link. Temperature rise in the wells As pointed out earlier, each weil is washed out with salt water—about 0.J litre per second. This quantity is sufficient to limit the temperature rise to a minimum. The voltage drop in a weil is about 10 V ata current of about 40 A, i.e. a loss of about 400 W. Cooling from the circulat- ing water alone would result in a calculated rise in tempera- ture of about | degree. A great deal of heat is, however. conducted to the earth and to the air, limiting the tempera- ture rise to an unmeasurable value. As mentioned earlier the temperature in the test wells rose about 40 deg. C when water circulation was stopped. The temperature rise in the wells in the final station with longer and thicker electrodes was measured in the week from 15th to 22nd July, 1965, when the link was operated fairly close to its maximum capacity throughout day and night. The maximum rise in temperature is about 0.006 i?, where “i” is the current through an eiectrode, i.e. about 15 degree at SO A. : The difference in temperature rise between the test wells and the final wells is not only caused by the difference in size, but also in the salinity of the sea water at the sites. The sea water in Kolding Fjord, where the initial tests were made has only about 0.7 times the salinity of the sea water in the Kattegat. The specific resistance of the salt water pumped to the final station is about 0.25-0.30 2.m, measured at 20 deg. C. The specific resistance of the chlorine-saturated liquid. which is formed in the wells after severe! days without water circulation, has been measured to be almost the same as that of the sea water present before the water circulation was stopped. The acidity, pH=5-6 for sea water, changes to pH=0.7 for the chlorine-saturated liquid. Operating experience The electrode station has so far operated quite sa factorily. Some details have, however, been altered. — ; a NC NUE NNT) 2 Ss } od Surface potential gradient -mV/metre - 1000 A of 02 05 «1020 ar) Distance from centre of electrode system - km Symbols: x Gradients evaluated from vollage measurements in the shallow water perpendicular to the coast line, (direction—South- East). AGradients evaluated from voltage measurements along the coast line, (direction— South-West). aGradienls measured along the coast line, (direction- South- West). ©Gradienis measured along the coast line, (dinection- North- Egs?). ‘+ Gradients measured in differen? inland places, (direclions between North and West). Inclined lines show values at apparent resistivity according fo the formula for a uniform Hemispherical Field G:2mr? if 6. ? or = 2n-p? P + potential gradient in V/metre + dislance in metres. current (1000 A) earth resistivity in Q«m CHT « oc 3s-9 Figure 9 DIAGRAM OF GRADIENTS, MEASURED IN DIFFERENT DISTANCES AND DIRECTIONS FROM THE STATION, WITHIN S00 METRES FROM THE STATION THE APPARENT RESISTIVITY OF THE SUBSOIL 1S APPROXIMATELY 5.2/s. AT GREATER DISTANCES THE MORE STRAYED MEASUREMENT POINTS TO A SOMEWHAT LOWER APPARENT RESISTIVITY, ABOUT 22]m 62 107 The salt water wells in the sea bed were not quite able to supply the intended amount of water. At low water, when the area around the wells dries up, they were rather in- effective after about two hours, as all the water from the surrounding area was pumped out. It is normally low water twice every 24 hours for about three hours but, - especially in the months of February to April, low water may last for several days. In January, 1966, a prolonged period of low water occurred leaving an exposed and frozen sea bed. This opportunity was used to increase the efficiency of the wells by laying drain pipes into the sea bed around the salt water wells. Some 150 metres of 3 in. diameter PVC pipes with slits were laid at a depth of 0.8 to | metre to drain water from wider areas. This has brought the minimum water capacity, even after several days of low water, up to about 10 m/*h, corresponding to 0.11 litre per second per well. : It has been necessary to rebuild the pipe installation at the pump. The pump is in a marine finish, with wet parts in bronze. Between the pump and some valves, also made of bronze, a length of iron pipe had by mistake been inserted and this was corroded by electrolytic action. This fact was not discovered until after a few months of opera- tion, when the pipe broke, having corroded through from the inside. At the same time the pump motor was changed due to defective bearings, probably because the motor had been flooded by the accident. Plastic pipes are now uscd throughout. At first the graphite anodes were suspended as shown on Figure 3. Cracks halfway through the submerged part of the insulation on the cables were, however, discovered on inspection in September, 1965. It was not possible to re- new the cables as these are cast into the graphite and the electrgdes were therefore raised until the top was about 5m above water level. The cables were then free of the salt water and we did not have to renew the electrodes, on which the corrosion after only four months of operation was only just visible as a rounding-off of sharp edges. By raising the electrode, only part of it was now opposite the slit-up area, whereby the effective length was reduced Ficure 10 EQUIPOTENTIAL LINES AT DISTANCES UP TO ABOUT 1,000 METRES FROM THE STATION May 1966 DIRECT CURRENT Values of gradients | and potentials are per [000A Gradients in mV/melre perpendicular in line “ equal potential Ficure I! MEASUREMENT OF TWO CLOSED EQUIPOTENTIAL CURVES AROUND THE STATION. THE FLAT AND MOIST MEADOWS ON LAND AND THE SEA BED, EXPOSED DURING LOW WATER, GIVE IDEAL CONDITIONS FOR THESE MEASUREMENTS and the resistance per weil rose from 0.63 2 to 0.77 2, i.e. by a factor of 1.22. Measurements of the change in voltage distribution, in and around the wells, showed that the increase in the total earth resistance for the station was less than for a single well, it rose from about 0.04 2 to about 0.0475 2, i.e. bya factor of 1.19. When the electrodes have to be changed, at some future date, longer graphite rods or a better cable insulation material will be used. An insulation of vulcanized poly- ethylene mixed with powdered graphite has been sug- gested. The electrode station is not under daily supervision but is inspected at one or two weeks interval. It has been necessary occasionally to remove sand and mud from the bottom of some of the wells where the water circulation had failed. On these occasions the current carrying electrode can be drawn out of the water without discon- necting it electrically first. No switches or isolators are found necessary. The electrode having a voltage of a maximum of 15 V when drawn out, may be handled with bare hands, but rubber gioves are advisable also because the electrodes are slimy and dirty. Of course only a few electrodes must be drawn out at a time when the station is in operation. During ail fault conditions, periods of rebuilding and cleaning up, etc., it has never been necessary to interrupt the transmission. Influence on the surroundings Experience, for instance from the Gotland link, show that the voltage difference in the sea acts on fish in sucha way as to draw them to the anode. At Sora, where the electrodes are placed on land, the gradient at the normal coastline is 0.3 V/m, at the most. This has, however, apparently not been enough to attract fish. The area south of the electrode station is very marshy land, which is used for grazing. The maximum gradient in this area is 0.2 V/m and this has not been observed to have any visible effect on the cattle. DIRECT CURRENT May 1966 108 4V above remote earth Y above Q 0 20 30 40 50 remote earth Uesebesseliereleetlitenterelirnterilersetinral : Metres Values of potentials are pr. 10004. Surface potential is almost consignt close to the ceninal walls. Potentials of electrode rods inside the wells :- _ Well number 13 — 39-5V - ” Well number 7 — 38-5 Well number { — 37-0¥ oeas-i2 Ficure 12 EQUIPOTENTIAL LINES CLOSE TO THE ELECTRODE WELLS The clectrode station does not affect vegetation. The plants in the area, grass and reeds, grow quite normally at the site, even close to the electrode wells. Economy If, for some reason, it had not been possible to use the earth as return conductor, an additional cable would have been necessary. This would have given the following capital investments: : Million Danish : Kronor Return cable, total length about 85km_... 13 Losses in return cable and lines from converter ~ stations to return cables, 5,900 kW, capital- ised to oc 7 TT 7 = 7 Total an cm ms 20 By the use of earth return considerable savings have been obtained, which can be seen by comparing the above costs for a return cable with the actual costs for the earth return: Million Danish Kronor Anodic earth electrode in Denmark -- 0.20 Lightly insulated electrode line in Denmark (3 km) 7 co oe + «. 0.15 Cathodic earth electrode and lightly insulated electrode line and cable in Sweden (3 km line and 9 km cable) ae Fe -» 0.85 Losses in electrode lines and stations, incl. lines from converter stations to electrode line tee-offs, 1,930 kW capitalised to ws 2530 Total .. a .. 3.50 Thus the resulting savings by using earth return in the ~- Konti-Skan case amount to approx. 16.5 million Danish Kronor. 63 ~14-69 (sc) 42 A_ SURVEY OF CORROSION ASPECTS RELATED TO TES OPERATION OF ELECTRODES FOR HVDC GROUND RETURN A report to Study Committee No. 36 (Interference) (Volgograd 1969) by Ingvar Lidén and Heine Martensson of ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET Ludvika, Sweden 109 Content Summary Is Presentation of projects, electrode design and electrode operation 2. Measures taken to prevent corrosion on buried structures 2.1 Selection of electrode site 2.2 Distances to buried objects 2.3 Other measures for protection of specific objects 3. Experienced corrosion Conelusion 110 Sumsary 1 The survey is requested by the former corrosion Sub-Cczmittee for Liason between Cigzé and CCITT. The survey should provide information on the systezs of direct current transaissien al- ready used or likely to be used in tke future, with special reference to corrosion matters such es magnitude of the direct current passing vie ground and measures that can be adopted to reduce the effects on other buried structures. Different users of HVDC transmissions have been asked to pro- vide related information and the survey is basicly a summary of the answers obtained,with extracts from earlier literature on the subject incorporated. Only two cases of corrosion damages related to electrode ope- ration and experienced on objects outside the electrode station have been reported. This survey is therefore mainly dealing with the selection of electrode site, design of electrodes and other specific measures taken to prevent corrosion. For the detailed knowledge the reader is referred to the Utility in question and to the literature specified in enclosure 1. The authors are grateful to the Utilities end the Consultants for placing the basic information at their disposal. Presentation of vrojects, electrode design end electrode operation 2 As a background for the understanding of the measures taken to prevent corrosion the electrode arrangement, site conditions and operation requirementscthe investigated projects are sum- marised in table 1. Measures taken to prevent corrosion on buried structures 2.1 Selection of electrode site The selection of an efficient electrode site is the primary step to be taken in order to decrease risks for corrosion on buried structures. However many factors influence the choice of the site and evaluations have to be made as to the costs for electrode line and cost for effective grounding taking into account the losses, durability of grounding resistance, step voltages and required protection against corrosion. As the resistivity of the ground rarely is uniformly distributed, it is not feasible to precalculate exactly the current densities and thus the corrosion risks for buried structures. However practical guidance can be obtained theoretically under the pre- sumption. of even resistivity distribution with due regard taken to the influence of well conducting nearby sea. Metheods for the calculation of current densities to be anticipated for dif- ferent parameters such as type of csjects, location in relaticn - to the electrode and ground resistivity are given for instance in the literature [1] according to enclosure 1. In general, ceasure- ments on test electrode arrangements have been cade sy the Utilities at the intended electrode sites giving basic for the definite design of electrodes and corrosion protection to be foreseen. On the final installation, measurerents of the LLL 2.2 Distances to buried objects structure to soil potential difference end the structure currents can show if further measures for protection are required. The literature gives for instance the folloing current densities as acceptable 0.1-1.5 pa/on” for cable armouring where 1.0 pa/om@ is an internationally accepted figure 5-7 pa/em? for pipework. The current density of 1 pA/en® corresponds to the loss of 0.174 mm iron in 15 years Distances from the selected electrode sites to buried structures are specified in table 2 and visualized in diagrams 1 and 2. It can be observed that the closest plastic insulated cables for low volgage distribution and telecommunication, grounded distri- bution transformers , small water piping and unprotected metallic structures cen be found in a distance of 0.5 to 1 km from the electrode. More widespread odjects,such as distribution systems for gas electricity and tele, appear et 1 to 10 km. The distances to submarine cables range from 8 to 13 km and urban areas with more than 1000 people can be found down’ to 2 km from the electrode. A direct comparison of the figures for different projects is not feasible as too meny conditions influence the final outcome of distances. For instance the desire’ to.utilize-a:site which offers suitable -grounding:.donditions’.is1a° largely.influencing factor, However, in general, the figures reflect the circumstances exemplified in Rusck's theoretical evaluations. Thus the existence of transmission cables and other widespread objects has been the decisive factor in the main location of the: electrode site. This is indicated for instance through the. relatively equal distances for submarine cables (CTS). Smaller structures may influence the location in the selected area. The sea electrode arrangement has permitted shorter distances to land objects than to submarine. For instance the average, equivalent current,distances to land distribution (CD) and transmission (CT) cables is 5.5 km as compared with 9 @ for submarine (CTS) cables. The lend electrodes are-too few to trace from the figures any tendency that these electrodes require larger distances for large ods e due to higher surrounding resistivity 112 2.3 Other measures for protecticn of buried objects 2.3.1 _ Gotland If the electrode is located so that the design objectives above are met for larger essential cable or pipeline installations or other widespread objects, it is anticipated that severe corrosion could aprea> only on elezents located very close to the electrode or on less important elerents of considerable length. Corrosion damage on such elements can develop also during short operation time. It is also anticipated that if corrosion damages can be expected or found to develop on such objects,the consequences will be limited and inexpensive means to avoid or protect against a repeated damage on the installation can be found. With the electrode sites chosen utilities have considered it justified to take some additional measures to avoid corrosion on nearby structures such as equipment in the electrode station, electrode line towers and fencing. The following is a summary of such measures. Calculations: showed that also with the very low figure of Q.1 pA/cm? it was possible to locate the electrode stations down to around 10 km from the power cable -end existing teletransnission cables on the mainland side, where the sea bottom is sloping. Even shorter distances could be accepted at the Gotland side, where the bottom is steep at the shore. The electrodes at Vastervik were originally housed in earthen- ware tubes placed on wooden runners, which could be withdrawn from the water for inspection and replacement. The planks in the wooden runners were fastened together by wooden pegs. However, because of the action of ice on the tubes and the agression of chlorine on the wood the electrode station was rearranged according to fig. 1. The platform bridge is still made of wood. ‘The electrode line passes three inlets where plastic insulated cables without lead sheathing are used for the crossings. A cable for 400 V distribution to an island at a distance of 4 km passes 500 m from the electrode station. This cable has also a plastic insulation. For this transmission project a cable return arrangement has been selected. In the planning stage the feasibility of ground return was studied. Tests were carried out on existing 33 kV and telecommunication cables to verify theoretical consideretions concerning effect on ship's compasses, induced voltages in tele- communication cables and risk of corrosion from DC stray currents. The shortest distance between electrode and test object was around 1.4 km. The change of cable sheet potential end earth current was measured to 210 mV and 6 mA respectively when passing 200 A through the electrodes. Though not applicable directly on an envisaged HVDC link ground return and electrode arrangement the test indicated that the large number of teleprone caoles crossing the Channel and the existence of other installations on shore would make it difficult to place the sea electrodes sufficiently far away to eliminate LU 2.3.3 Cook Strait 2.3.4 Konti-Skan completely any risk of electrolytic corrosion if sea return arrangements were used. The corrosion aspect was therefore one of the reasons for using the cable return arrangement. The requirement of 1 pA/mm? current density on cables and structures at Benmore power and converter stations and the desire to utilise a low resistivity tertiary soil area lead to the location of the Benmore land electrode. Checking with Rusck's formula indicated that the site intended for the sea electrode at Haywards was far enough from the power cables at Oteranga Bay (approx. 13 km) +o ensure thet the cable armouring current density would not be more than 0.47 pa/em*, when electrode was operating at 1200 A. In all the cases investigated, concerning risk of corrosion on cables, buried objects in populated erees and grounding systems for radio receiving stations etc., it was found that the chances of any corrosion were extremely slight, mainly because the sea would absorb the major part of the current. The Benmore electrode line is connected to the lend electrede arms by isolating switches in a switching house. The foundation of this switching house is unreinforced to avoid corrosion. Steel towers are installed for the electrode line except for the last few spans within less than 0.6 km from the electrodes, where wooden pooles ere used. The voltages between a wire fence and the adjacent soil at the electrode site were found to be undesirebly high. Therefore fences within about 2 km of the land electrode were modified to reduce continuous fence wire runs to relatively short in- sulated lengths. In some places earthing of the wire has been satisfactory. : A small water pipe for farm house supply near the land electrode has been interrupted by the insertion of a length of plastic piping. Checks will be carried out on nearby buried metallic objects including tower footings and cable armourings to assess the corrosion risk. Also for the sea electrode at Riborg, the design objective has been to limit the current density to 1.0 uA/cm* at 250 kV DC and 20 kV AC power cables. The smallest distance between electrode and these cables is 8 kn. To prevent corrosion on the water supply eauipment for the electrode wells wet pump and valve details are made of brenze. Plastic pipes are used throughout. 114 The electrode line is terminated at a stayed steel tower. The foundations of the tower and stuy are 13 and 8 meters fron the wells. In order to insulate the foundation blocks frem the soil and prevent corrosion on the armouring rods, the foundeticns exe enclosed in layers of thick polyethylenfoil. The Utility has used electrical drainage for the protection of the electrode line terminating tower. The tower and stay and consequently all the armour rods are grounded: to two graphite electrodes placed in the ground ebout 16 meters from the electrode wells. The potential at this distance at 1000 A is approximately 1V less than the tower foundation and approxicately 4 V less than the backstay. foundation. A. possible leakage current through the foundation insulation will therefore not give any corrosion problems ‘ Auxiliary power for the site is teken from an existing supply ( : transformer about 600 m away. It passes through a 3x16 mm plastic insulated cable. The cable is not provided with ea neutral conductor as an insulation fault would result in a d.c. current to ground through the starpoint of the transformer causing corrosion on the transformer grounding connection. - The fence surrounding the electrode station is, as far as practicable, arranged along one potential line. Stray currents _in the fence deriving from the residual potential differences axe further reduced by the subdivision of the fence into mutually insulated sections of about 10 m length. The plestic covered fence is not grounded at any point. At the Gothenburg electrode station the feeder conductor from the electrode line to the electrode consists of a plastic insu- lated cable without wire armouring. 2.3.5 Sardinia’ The Sardinian anode electrodes are suspended from a timber bridge. The risk for corrosion was one of the reasons for rejection of en alternative arrangement utilising a reinforced concrete bridge. The two cables supplying the mainland cathode are steel wire armoured against damage during leying and separately covered ‘with insulating plastic. The electrodes are formed as an unin- sulated part of these cables. 2.3.6 Vancouver project As an example can be mentioned that before the final design of the electrodes a test was performed with a temporary anode and @ prototype cathode located in the area for the final installation. A current of approximately 280 A was circulated using sea return and joint measurements were undertaken with the party concerned on buried pipelines and submarine cables etc. At the same tine results on resistance, temperature rise, and chemical effects were obtained on the prototype cathode and were used as a basis for the design of the final installation. 115 2.3.7 Pacific Intertie 2.3.761 Celilo In the electrode design certain measures have been taken to prevent corrosion. The feed cables from the electrode line to the three terminal boxes as well as the *4/0 copper cable feeder in the coke- filled trench will be insulated with high-density polyethylene. The metallic electrodes will be factory fabricated into series . of strings of five electrodes connected by 5-foot insulated cables and 5-foot insulated pig tail on each end of the string. All connections of the pig tails to the # 4/0 main distribution~ cable must be made waterproof to prevent electrolytic corrosion on the copper conductors. This will be accomplished by the use ( of commercially available splicin kits consisting of a plastic il mold which is fitted over the splice and then filled with epoxy casting resin. No specific measures have been taken by the utility so far to avoid electrolytic corrosion of other buried structures. Con- sideration is being given to means of protecting steel trans- mission line towers in the immediate vicinity of the ground electrode. The following possibilities have “been considered: 1. Install towers on concrete footings instead of the customary steel grillage. 2. Employ conventional steel grillate footings, but protect them with an insulating coating. 3. Surround the tower footings with a screen of sacri- ficial electrodes to intercept current on one side and discharge it back into the earth on the other side of the tower. All gas pipelines in the area have insulating coatings and are equipped with impressed-current cathodic protection systems. These protective measures are normally taken by pipeline owners as a standard practice which was adopted long before the advent of HVDC transmission. The Pacific Northwest-Southwest HVDC Intertie has been designed and will be operated as a balanced bi-polar system. Any earth current problems are not anticipated which cannot be handled adequately by conventional meens such as cathodic protection. Confirmation of this must await energization of the first d.c. line, at which tire fullscale tests will be conducted. Sylmar Ground return tests have been carried out over 240 miles distance with the Sylmar Station ground rat as an electrode to explore the possibility to use a landelectrode in the Los Angeles area. Measurements of pipe-to-soil potentials, current discharge into 116 the anode bed of a common cathodic protection system and potential drops were made on nearby pipelines and telephone cable sheaths. Since the entire Los Angeles area is underlaid with pipelines and other structures, it became apparent that any surface electrode situated within a reasonably distance from the Sylmar converter station would create electrolysis problems. Consequently further study was directed towards electrode types that would result in reduced earth field strengths in the yicinity of the electrode. These studies verified by tests on offshore electrode clearly demonstrated the reduced field of an ocean electrode. The eight miles at the beach end of electrode line will consist of two parallel 1250 MCM 91-strand copper single conductor, 15 kV paper insulated, lead covered cables mostly in duct banks for 34.5 or 5 kV circuits. The two cables terminate on 2 common bus in a control vault near the beach from where two 3-conductor underwater cables connect to the electrode. Each conductor will be 300 MCM copper with 5 kV polyethylene insulation. The cable has a polyethylene jacket. The electrode elements inside the concrete shields will be suspended by polypropylene rope slings attached to the top section of the shield. 2.3.8 . z Additional notes It is interesting to note that no cathodic protection has been reported to be installed yet as a consequence of the electrode ‘installations. On the other hand cathodic protection installed for pipelines to protect against currents from other sources has enabled Utilities to regard them as fully protected against redundancy stray currents from the electrode. Ground wires on transmission lines can conduct ground currents between places with different ground potentials and low grounding resistances causing corrosion in for instance stays spanners etc. Similar phenomenon may appear in transmission and distri- bution systems with transformer neutrals grounded at widely separated points in the electrical field from an electrode site. It must also be checked thet a possible stray current will nee cause d.c. magnetization of the transformers. Experienced corrosion The very few corrosion damages reported so far seem to verify the expectations on the electrode design stage. 3.1 . . Gotland . During 1961, seven years after the commissioning of the trans- mission, inhabitants on the island, where the anode electrode station is located, claimed that the current from the electrode station caused corrosion on boats with aluminiumsheathing. To 117 o> 3.2 Volgograd-Donbass Cook Strait 3-4 Konti-Skan 9 clarify the phenomenon a test was performed from 14th December 1961 to 31st October 1962. Aluminium sheets of different quality were placed in the water at distances varying fron 5 to 2300 meters from the electrede station. No traces of corrosion originating from the electrode current could be identified on the sheets. After the tests were finished it wes explored that the aluminium sheets delivered to the boat-builder were not of required quality. In connection with cable faults 1963 and 1964, caused by mechanical damage, parts of the sea cable from sections between 12 and 30 km from the electrode station at Vastervik were . inspected. No corrosion could be found on the lead sheath or the armouring. Corrosion of the lead sheath in one position of the land cable 17 km from the electrode at Vastervik wes ‘ discovered 1963. ‘The reason is somewhat doubtful but as lime has been found in the damage and near the cable the corrosion is considered to be caused by chemical action. Inspection of distribution line stays spanners etc. in the surrounding of the elctrode station has not lead to the _ Getection of any traces of corrosion. No other corrosion damages have been experienced. The measurements of the influence of stray currents on the stretched unterground structures have shown that they well approached the design values and that the measures taken in the design proved to be quite sufficient to prevent their electric corrosion. In a distance of 1 km from the south Island land electrode there is a water pipe of very small size for e farm supply. Severe corrosion was discovered on this supply after a period of electrode service, but how much the earth currents contributed was not known as the pipes may have been very old. The pipework was interrupted by the insertion of a length of plastic piping. Apart from this one case of corroding water pipes there have been no other reports of corrosion exceeding normally observed rates. Checks are carried out on nearby buried metallic objects, in- cluding tower. footings and cable armourings to assess the corrosion danger. The electrode at Gothenburg is situated around 3000 m from the basic shore line. However there is a populated peninsula at around 2000 m distance from the electrode. The electrode is = carrying negative potential. In this area certain corrosion has been experienced on lead-sheated teletransmission cables. The potential change on the cables has been measured at 0.4 V, on electrode energizing. 118 Conclusion 10 In Aalborg electrode station has been necessary to rebuild the Pipe installation at the pump. The pump is in a marine finish with wet parts in bronze. Between the pump and some valves, also made of bronze, a length of iron pipe had unintentionally been inserted and this was corroded by electrolytic action. This fact was not discovered until after a few months of operation when the pipe broke having corroded through from the inside. Plastic pipes were then installed throughout. No corrosion damages have been experienced outside the electrode station. It is within the nature of the corrosion problem that unacceptable deteriorisation dces not necessarily occur or become apparent until after a very long period of aggression. Furthermore uneven distribution of ground resistivity and conditions, such as unknown interconnection of buried structures, can give rise to unexpected local corrosion. However the experiences. of damages obtained so far and the results of controls performed do not contradict the opinion that theoretical methods and practical test results are at hand for the overall judgement of the corrosion risks for buried structures when it concerns the design criteria for HVDC ground return electrodes. 119 L469 4 ASEA Specification 1 . literature’ basic for the survey CJ Rusck, Ss HVDC Power Transmission: Problems Relating to Earth Return. Direct Current, Vol.7, No. 11. November 1962, pages 290-300. B.G. Rathsman and A.U. Lamm: The Gotland HVDC Transmission and the Underlaying Work. Cigré 1954. L. Csuros and J.M. Cranmer: Experimental study of the Effects of Using Sea-Return. IEE Confexence publication 22, 1966, pages 435-438 A.M. a Fil. Butaev, E.S. Grois, A.V. Posse, S.S. Rokotyan and P.E. Sandler: Operating Experience of the Yolgograd-Donbass DC Transmission Line and its Applications to Extra High Voltage D.C. High Capacity Trans- missions. ¢ 1968 Cigré 43-07. D.G. Dell: The Benmore Land Electrode Reprint from N.Z. Toginsezing, 20(5) 2165-175 (May i565 D.G. Dell: The North Island Sea Electrode Reprint from N.Z. Engineering, 20(6):213-222 (June 1965) EB. Andersen and M.R. Nielsen: The Anodic Earth Electrode for the Konti-Skan HVDC Link Direct Current Yol.11, No.2, May 1966, pages 54-63 S.D. Thorp and D. MacGregor: Design of the Sea Electrode System Sardinia-Italian Mainland 200 kV scheme. IEE Conference publication 22, 1966, pages 431-434 H.M. Ellis and W. Chin: Major Features of the Vancouver Island - = 260 Kv EvDC Submarine Link 1968 American Power Conference Carleton L. Waugh: The Rice Flats DC Ground Electrode for the Pacific Northwest-Southwest HVDC Intertie. Western Water and Power Ryaponni, pogeeenOety April 8-9, 1968 in Los Angeles. G.R. Elder :end D.3B. Whitney: fhe Los Angeles HYIC Ocean Electrode Western Water and Power Symposium, Proceedings, April 8-9, 1968 in Los Angeles. 120 L469 a Tabl 121 o4 Table 1 Start Electrode desicn Electrode operation of Pp. c Planned |M i Utility Project ope= Type city eed anaes pene Pola- pate Period | Remarks ration Amanode jratingjutili- |dimension rity jload | . zation Cecathaig A Se y/ and data KAR % time F ! SSPB Gotland, Vastervik | 1954 Shore! A 200 | Mono Fig. 1 A 15 March 1954 polar $8.yer~ ssPe Got land ,Visby 1954 |Sea ¢ 200 | 100/100 |rig, 4 c 145 : cess Cha ; tpgge Charme! | 961 [Ne Bipolar Cable return y EqF Ch EER onee anced 1961 No . USSR Volgograd-Donbass Vv Bit va jelzhskaya 1962 [Land | Mac 300 Bs ie Son's at Mostly Ft ‘aie 4962-1987 . : USSR Volgograd-Dondass moqo- veericitdy in one i rr Mikhatlovekaya | 1962 [land] Ac | o00 | fe oat ly poere= | ifea® tion tranches NZED Cook=Strait sie Benmore 4965 |tand| asc | 1200 | Sn Fig.2 a 143 polar c 7 $863 t0 NZeD Cook-Strait ca anery Haywards 1965 Land At 1200 188 ong. Fig.3 A 2 periods Cc 1.3 EPOC Sakuma 1965 | No e-station rPequenc: ’ converte! ELSAM Konti-Skan Aalborg 1965 [Shorey A 1000 Mono= i Figed A 18 ssPs Konti-Skan sony 138s, to Gothenburg 19%5 [Sea ¢ |1000 Fr | Figes c | 18 1368 ENEL (PCR)| Sardinia,Sardinia | 1966 Shi A 1000 | Mer Fig.5 A |>2 0. (PCR) dinia,Sardin: ore poise 9) 3888 is ENEL (PCR)| Sardinia,Mainland | 1966 | Sea ¢ |1000 | 100/ | Fig. c |>2 {385° 100 8CH Vancouver Vancouver Island 1968 | Shore A 4200 | Mono- Fig.6 A s Fags: polar 2 B to BQH Vancouver i335" Mainland 1968 | Land c 4200 | 100A00 | Fig.7 c 3 F Common fh BPA j Pacific Intertie sear fetur or w | Celilo I (and 11) | 1969 |Land| 44c | 1600 baried | Fig.8 iensaissione wees Ely LaowP Pacific Intertie F4ggier Fig.9 Sylmar 1969 |Sea Ae 1800 | brief j a Table 2 Approximate distances (km) from electrode to buried structures Ob ject Pipeline Distribution pipes cas Distribution pipes liquid Cables ic coated distr, or teld Telecomm, Distr, S10 W Transa, 210 kV Submarine Metallic structure Armour ing Railroad Storage tanks Steel tower Transformer directly Grounded Distribution Transmission Urtan area >1000 people & corroded xv ec 9288 8° a4 3) 8 * ~ ad 0.5 12 17 17.5 0.5 10 10 410 10 10 20 122 0.6 13 0.6 7.5 Konti-Skan 0.8 0.8 25 74 12 410 10 10 10 10 10 10 1 10 10 10 Table 2 \Vancouver >1 >7 24 13 11.5 11.5 3.5 Is lang} land Main: 3.5 29 11.5 41,5 1 12 11.5 1 11.5 shore electr Tei Se 3.8 0.2 O¥stance 0 to buried cviccts Shore and sea electrodes Pipeline gas liquid Cables plastic coated telecommunication distribution <10 kV 0 . = transmission > 10 kV * submarine 4 Transformers grounded 20 u distribution <10 . transmission >10 Wetallic structure. armour ing steel tower u railroad = storage Urban area > 1000 people Corroded CTS according [1] formula 15,16 a7 SRS8RG° 2B S22 AF =) 33 7 Diagram 1 199 year Diagrem 2 . Distance 0 to buried obincts Land electrodes Pipeline gas liquid 22° Cables plastic coated telecorrunication distribution <10 kV transmission >10 kV . submarine 9883° a Transformers grounded distribution <10 kV transmission >10 kV Metallic structure arpouring steel tower railroad storage © @SRE* AT ke Urban area >1000 people { Corroded a p6,c0,45,0 “oo 124 1200 , 1800 4 1965 199 year » Site conditions Water resistivity Ground resistivity « Eleotrode design Polarity Type Electrode units number material dimensions Electrode unit housing Arrangement Measured resistance SeT Vastervik 70 ohm cm 1,400,000 ohm om Linseed impregnated . graphite L 1500 ma 6 85 mm Barrier only Spring suspended from wooden platform in brackish water basine on coast line Noninsulated smooth copper conductor One wire forming two parallel 120 ma Trench in rock for joint only One electrode unit on sea bed roef 350 m offshore One electrode unit buried at seashore and connected winter= time only. Each unit consists of one bioht of wire running from one electrode line conductor and continuing back to the other line conductor 0.5 ohm ORECTION TO THE 0oTtAno ___ ELECTROOE STATION Voltage differences between the Viistervik electrodes and earth, GOTLAND L armdpz Site conditions Water resistivity - Soil resistivity apparent 6150 ohm ca surface 3320 ohm cm to 36.3! = depth 10000 ohm cm to >500' Soil moisture content | Mean BY (4-21%) Soil quality Tertiary Unconsolidated quartz sand, silt and clay aa carbonaccus clay and lignite and graywacke . conglomerate » Electrode design Polarity AsC ; Type Land , SIX POINTED STAR ' Electrode units 3 . TYPE nunb or 6 arms ‘PLAN VIEW material Mild steel rod in coke dimensions L approx. 400 yards/ara 61.5" Electrode unit housing | Trenches cateriol Granulated coke perforation = dimensions Cross section 20"x20" Arrangement Horisontal ster arrange ment of arms in ground surface Calculated resistance Economic range 0.5-0.05 ohm Measured resistance 9,22 ohm “Ground surface potential map. » - Percentage of full electrode voltage drop to remote earth. | GROUND SURFACE © 8 8 8 yerees RETURNED SOIL ———— GRANULATED COKE | 6 | METALLIC CONDUCTOR orndt gy NZED BENNORE LAND ELECTROLE = te 9CL CHOSS-SECTION OF COKL-FULLED ELECTRODE 1, Site conditions Water resistivity FLECTRQOE, gin i Soil resistivity : Le apparent -. f ! 4 FINAL BEACH LEVEL surface 1000 ohm cm<10' water 4 fl i saturated shingle : \\ ee 2 BOULDER LAYER temporary . R200 STOPBANK dapth 100000 oh ca rock (Far, A . wa at78 MIGHEST HIGH WATER LEVEL Soil moisture content - 7 JUNCTION i za RSE —— ere sede I ne I Weil fceu. eves ib al See 2. Electrode design i : i SET IN CONTRETE |Lize2 -¢| CUT _OFF DRAIN LOW wareR 5-7 LOWEST LOW WATER LEVEL B, sinecehOce, Cee tan na t 7 160. TO SUMPS MARK Polarity Ase Le ee + NT ee ea ee Type Electrode units number 25 material Impregnated graphite dimensions L7', 66 Electrode unit housing - material Concrete pipe perforation 6% dimensions Let, g2! Arrangement : Vertical in backfilled beach trench drained by “y water tide 5 Calculated resistance 0.18 ohm : 3 Nes ne 0.23-0.3 ohm 2 Measured resistance é a ena 4 i Bie SWITCH HOUSE JUNCTION pal GE PIRES oto ITN a CONCRETE Pipes TH tir 68 FOE 681s b bk bb bh BO iss At > LIMITS OF TRENCH ! iw ROCK oot TRIAL CELECTRODE Tih 7 = TEMPORARY STOP DANK? j Beach Surface Potential Map. Percentage of full electrode APPROX. Uw _. —. — 1-— — — — — — ‘—-—-- al TTT iT LINE Voltage drop to remote earth, i Sea electrode final layouts. w Q Q - Mw Ler N.Z.E.D. NORTH ISLAND SEA ELECTRODE « Site conditions Water resistivity Soil resistivity apparent surfece Soil moisture content Soil quality 2, Electrode design Polarity Type Electrode units nuaber material dimensions Electrode unit housing material perforation dimensions Arrangement Calculated resistance Measured resistance 8?eT LAYOUT 0F THE ELECTRODE STATION Aalborg Goteborg ij ? 20 ohm ca 20 cha ca \ \ leclrode-lune, 80mm? ACR 200-500 ohm ca . Vs nea timm? Pvc insuleled copper 100-1 oha ca alle. One for each “Mumber % shown only 100%, partly saline water 0-1 m depth: Seach sand 1-approx. 200 m: Glacial deposits: Alue clay, sand, moraine, etc. ces Qullow dich wilh Approx, 200-400 m: Chalk, lime,thin layers of marl 7 A NS hon of Flow . sea-botlom Approx, 400-1500 m: : A PVG suction pipes for ; Ht water Layers of sand, cley,hard clay etc. no www we ae par Below approx. 1500 a: . Bares Bat Sota Bed-rock,probably gneiss , . ° 50 100 Feet 25 Impregnated graphite Bare copper Speed y 7 L 2440 ma, 6 100 mm 300 =, 600 am Jumetion box None Sea waler level to be expected —+#52(flood observed 1893) 425 once in Syears DEN MARK +£00 once 3 year ss +075 Thimes 2 year Si 10 50 40 limes 2 year PVC pipe 16% (Normal) L 6000 mm, # 230 ma f Saitaae Vertical in beach wells drained Conductor arranged i ditch * Pe C-tube 25/25em dig by pumped sea water in a ring on sea bed Me ft ete eee e-s “ Insulated suspension cable Cxpected to be changed to at 10-15 m depth Horizontal in coke beds about 3000 m offshore 9,032 ohm 0.02 ohm 0,04 ohm 0.02 ohm “Graphite electrode Current: permesble sone EQUIPOTENTIAL LINES AT DISTANCES UP TO ABOUT 1.000 \itTRES FROM (prereset 1 Q 4 ? THE STATION HA Metres uh bg & a Be Konti-Skan a CROWES HON OF AN KERCTRODE WHEL 5 a Aalborg Site conditions Water resistivity Electrode design Polarity Type Electrode units nueber material dimensions Electrode unit housing material j perforation dimensions Arrangement 671 Sardinia 20 ohm cm A Shore 2x15 Platinized titanium tubes. Not plati- nized part coated with glass fibre. Total L*10" Platinized surface L-24", f-1,3" Breakwater only On line,at one metre spacing, suspension from pitchpine sup- port at the head of a bay 20 ohm ca Bare copper con- ductor 1 Conductors are anchored on concrete blocks above sand bottom at 26 m depth 2000 off shore WIPLATIMISED PORTION 26° PLATINISED PORTION ELECTRODE ELECTROOE GAY PUNTA TRAMONTANA Sardinian Electrode G emndty 1, Site conditions Water resistivity Electrode design Polarity Type Electrode units number material dimensions Electrode unit housing materiol perforation dimensions Arrangement Moosured resistance OCT 30-50 ohm ca 28 , . Linseed ofl impregnated graphite ts', g4" PVC tubes . Bottom 8 of PVC tube cut to semi-circular cross section. Electrode bar raised to avoid direct contact with tube L 20', 6 6" On line on sloping support inside rock barrier in salt water bay, < 0.1 oha — ' DISCONNECTS —— —— HIGH WATER ~~ —— Low WATER CREST OF BARRIER SEAWARD orouP | SIDE —> - SEAWARD SI0E ~~ OIA. PVC TUBE 4 GROUPS OF 7 ELECTRODES cGOv—mn_— oh. GROUP DISCONNECTS ELECTRODE Line ca ELECTRICAL CONNECTIONS FOR ANODE B£O ANODE INSTALLATIONS B.C. Hydro Vancouver Island Anode 9 amt 1. Site conditions “Soil resistivity Soil*moisture content Soil quality Electrode design Polerity Type Electrode units nunber material dimensions Electrode unit housing Arrangement Measured resistance TEL 150-200 ohm om Sand layer is seawater saturated Soft topsoil 4-5! Sand from 5' to 20° 40 Copper weld ground rods L 30", p 3/4" None Driven Vertically into sea water impregnated soil adjacent to the shore line 0.01 ohm ELECTRODE LINE a rs hae AREA FENCE i 30°x 3%" > wa GROUND RODS | 180'x1000° 440) —_t x to wan Cy oe 20! ~—_, Le _ -lgohe wa ELECTRICAL CONNECTIONS % | [eee POLE STRUCTURE | r WAST WAST 8 30'x 57," > COPPERWELO GROUND ROO | T TYPICAL_CATHODE BAR CONNECTION CATHODE INSTALLATION B.C. Hydro Mainland Cathode L amar 1. Site conditions Soil resistivity apparent 10,000 ohm ca surface 4500-7500 cha cm depth S150 Soil moisture content Soll quality 5-14% over yoar Wind-deposited silt rich in minerals Electrode design Polarity Type Electrode units Ase Land nueber 1067 material High silicon cast iron dimensions L 60", 61 1/2" Electrode unit housing matorial Coke filling perforation dimensions Cross section 2' x 2! Oepth of electrode centre S$! Arrangement Horisontally, circular arrange- -ment in ground surface. Fed by three insulated radial buried cables at 3 points equally spaced along circumference 0.057 ohm 0.04 ohm (subject to confirmation by further more refined measure- Calculated resistance Measured resistance ments HB w Nt TO CELILO +-€ CELILO-SYLMAR CENTER OF ELECTRODE 700 MCM CABLE ——s] EARTH SURFACE SOIL FILL 2 COMPACT TO ORIGINAL DENSITY . UNDISTURBED SOIL 4{—— COKE 4/0 AWG OIST. CABLE HIGH SILICON CAST IRON ANODE CENTERED IN COKE-TOLERANCE t3" (a) TRANSVERSE CROSS SECTION 4/0 AWG CABLE 11/2"D X 6O"L CAST EPOXY SPLICE CAST IRON ANODE Wasco Co Road 800 KV D-C LINE TERMINAL BOXES SPACED 120° APART 10670'-4/0 AWG 1067 ANODES 2'x2' COKE ENVELOPE SSF RVIRMTESTIRVTTS EARTH oecxrut—— (6) CIRCUMFERENTIAL CROSS SECTION Vanoyr * ELECTRODE ARRANGENEL/T PACIFIC INTERTIE D-C SYSTEM 1, Site conditions Water resistivity 543'-O" soho 2bg 282° 7 25%0-425'0" Begesgacs € SHIELDS Wl 1234 6 6 7 4% (8 1 17 18 19 20 2 22 23% INLIGHTED 2. Electrode design éuor eh orm Polarity A Type Sea oC 4 Electrode units ; [OATRA SHIELD SECTIONS j number 24 elements each with 2 rode a es m= material High silicon iron alloy cd FEET dimensions ts, 93" “i Electrode unit housing & 3 2» 2 20 METRES material Concrete p perforation 25-40 % of lateral area dimensions Lait, w7!, H Sta" Arrangement Horisontal linear arrangement 6900' offshore at 48 m depth on 1 1/2! and 3 1/2! level above ocean bed : CENTER Calculated resistance |<. 0.02 ohm SECTIONS Measured resistance” ELECTRODE SHIELDS 5 g B8O7TOM SECTION ELECTRODE ARRANGEMENT FACIFIC INTFERTIE D-C SYSTE/L TRANSIISSION LINE SYLMAL TERIVINAL LADWP 6 omndty ST uae Reference 14-€9 (SC) 42 Supplement to A SURVEY OF CORROSION ASPECTS RELATED TO THE OPERATION OF ELECTRODES FOR HVDC GROUND RETURN A report to Study Committee No. 36 (Interference) (Volgograd 1969) by Ingvar Lidén and Heine Martensson ASEA, LUDVIXA Sweden oat (wal) 134 Laz 75-09-08 Content Summary 1. Presentation of projects, electrode design and electrode operation 2. Measures taken to prevent corrosion on buried structures 2.1 Selection of electrode site 2.2 Distances to buried objects 2.3 Other measures for protection of speci- fic objects 3. Experienced corrosion Conclusion © 1:35 1 On request of CCITT the original report issued in 1969 has been updated concerning: new installations change of electrode design currents conducted through the electrodes measures to prevent corrosion experience or none-experience of corrosion to the extent such aspects have been reported. Totally eighteen electrode stations have been energized and eight are under installation. One shore well electrode station has been redesigned to electrode in coke arrangement. Generally the Utilities using HVDC ground return appears to have the corrosion aspect under continous observation. Serious corrosion has been observed in one case but installation of potential regulated cathodic protection has apparently got the problem under control. fo simplify the reference to the original report the original index of chapters has been used also in this revision. Presentation of projects, electrode design and electrode operation i 1.1 Projects tae, Hlectrode design Konti-Skan Eleven new transmission projects requiring totally twelve new electrode installations have been added in Table 1. The shore electrode for the Aalborg station was originally arranged as graphite electrodes in vertical beech wells drained by pumped sea water. After test operation of other electrode arrangements, the well arrangement has during the periode June 1968 - July 1971 been changed to graphite electrodes in coke-beds in the same location, Fig. 4a. The test operation also showed that it is not practicable to simply insert the electrodes directly in the sea bed, because the tare of the graphite electrodes in operation will be unacceptably large. 136 an Nelson River Cabora Bassa 133 Electrode operation 3. The electrode design is given in Figures 11a and 11b. The earth electrode at Cabora Bassa terminal is formed by three deep electrodes in form of graphite rods. The earth electrode at Apolo terminal is of conventional design. Presently totally eighteen electrode stations have been energized. The Mega~Ampere-hours conducted through the electrodes, given in Table 1, are updated. Measures taken to prevent corrosion on buried structures During the course of investigations underlaying the design of different electrode installations the following aspects on design criteria for corrosion interference have been reported from the Utilities. The peoples concerned with the actual selection of sites and selection of measures to prevent corrosion continue to t ( er 2.1 Selection of electrode site Design criteria A. com report that there are so many conditions, such as types of buried objects, ground conditions, electrical requirements etc to consider in each installation for obtaining of sufficient but not meaningless protection that recommen- dation of a few standardized and universal design criteria should be of no practical guidance. Each case has to be treated on its own merits. On the other hand it should in the design work be useful to have access to reports on corrosion damages which have occured and a detailed specification of conditions prevailing in each case. 137 + B. The following are examples m design criteria which have been found realistic: 1. Coated pipe lines, to be protected by cathodic protection. A maximum limit to acceptable pipe to soil voltage will promote the proper design of cathodic protection. With respect to uncontrolled cathodic protection a limit of 0.2 V may be discussed. However, this figure can be too high and it can be too low for the specific case. 2. Uncoated pipe lines 2.1 Network The HVDC may be of the same order as the background current. 2.2 Long pipe lines Continuous DC 1 pea/en® Intermittent DC 10-20 jaa/ea Cc. Because disturbances can originate from other sources than the HVDC transmission electrodes, such as tramways, welding, furmaces telluric currents, soil conditions etc. the specialists have found it advisable to first consider protection of essential buried objects by means of for instance cathodic protection. This will form a base for judgement of measures required with respect to an intended HVDC electrode operation. 2.2 Distances to buried objects Table 2 is revised and distances for Nelson River are added. 2.3 Other measures for protection of buried objects Pacific Intertie In June 1970 a full scale (1800 A) ground current test was conducted using the actual electrodes at Celilo and Sylmar terminals. The purpose of the test was to determine quanti- tatively the effects on underground structures from emergency monopolar ground return operation of the Pacific Intertie HVDC System. 138 Kingsnorth Nelson River Current effects from the testing were detectable on a coated pipe line as far as 200 km from the sea electrode. Nevertheless, an evaluation of the data on pipe current and pipe-to-soil potential changes for the specific ‘structures observed in the tests verified the effectiveness of the electrode design in minimizing interference. The analysis of test data shows that no significant adverse effects to buried metallic structures will result from normal bipolar operation and emergency ground return operation of the Sylmar terminal. The Beddington/Willesden terminals are located within the area of London in close vicinity of numerous buried installations. It. follows that the operation of ground electrodes at economically benefical distances from the terminals should introduce serious risks for electrolytic corrosion. Therefore a cable is installed as a neutral connection instead of a ground return circuit. The power circuit is during operation grounded in one point only. Pilote test programme Prior to the final design of the electrode a test programme in co-operation with owners of the major pipe lines, railways and commmications facilities was performed in order to collect data for the design of the electrodes as well as for prediction of possible interference with buried structures, transformer installations and signal system operation. Two lengths were selected for the dipole,namely 145 and 380 km. Nominal discontinous currents of 330 A, 247 A and 165 A were applied in the long dipole test. Summer as well as winter conditions were tested. Concerning remote potential gradients the measurements show: 1. Negligable difference between winter and summer conditions. 139 2. Better correlation to theoretical values based on two layer assumption than based on homogeneous earth assumption. However, homogeneous earth assumption might be sufficient at greater distances. (In this specific case 30 km.) 3. Linear relationship between gradient reading and current level. 4. Very little influence, if any, on the gradient pattern (within surveyed 20-25 % dipole length) when changing dipole length from 145 to 380 kn. 5. Natural phenomena lead to potential gradients which frequently exceed those measured and predicted for the final electrode beyond 5 to 6 km from the electrode. Site area conditions and precautions The electrode at Dorsey (south) is installed in a distance of 32 km from a populated area. However, the built-up area and the related pipe lines are concentrated along two river parts forming an arc at approximately constant distance from the electrode site. Accordingly the pipe lines have little radial extention in relation to the electrode and are expected to be little affected by the ground current. A rock out- cropping between the city and the electrode may have a shielding effect on the most heavily populated areas. Gas distribution lines in the city are coated and cathodically protected and are divided by insulators in lengths usually not over 400 m. This normal practice for good corrosion control has been used without reference to HVDC. 4 6" and 8" pipe line was installed 1967 when the future installation of an HVDC electrode, but not the position, was kmown. The line was divided by insulating flanges into sections about 8 km long in order to reduce possible effects of ground currents and to simplify the protection. The pipe line is 140 “T- running at distances from 31 km up to 60 km from the final location of the Dorsey electrode. Measurements confirm theoretical expectations that damage could occur to the pipe line in case it were not sectionalised ty insulating flanges. Sectionalised lines should according to the measurements have a negligible interference. The SSPB have reported (74-05-30) that no further corrosion damages have been discovered than those mentioned in the original survey. 3 Experienced corrosion ' Gotland { Volgograd-Donbass Cook Strait Konti-Skan No report on corrosion has been received. The NZED report (74-07-08) that the annual inspections of booth electrodes have been continued. No new problems have arisen and there is no evidence of any new corrosion. No. other points of interest have arisen. Aalborg No corrosion damages have been discovered round the Danish electrode which is operated as an anode. Gothenburg The Telecommunication district of Gothenburg is an area where the ground is less homogeneous which has caused a relatively high rate of corrosion damages to uncoated metallic sheeted telecommmication cables. A few years after the commissioning of the Koni-Skan Power transmission,a somewhat increased rate ~ of corrosion damages was observed in a coast area close to the electrode south of Gothenburg. Investigations in the autum 1966 showed that currents (of the order 0.1-0.5 A), flowing in the lead sheets of the cables in this area, derived 141 ; ager from the electrode current of the Konti-Skan link. Due to these findings plastic insulated lead sheeted cables are since then used locally in new installations and on exchange of damaged cables as has generally become the practice in areas with high rates of corrosion damages. However, a combination of unfavourable circumstances (the soil conditions, the cathode potential of the electrode and the location of essential parts of the larger uncoated leads— heated telecommmication cables radial to the electrode) involve that the leakage of the cable sheet currents to ground will be concentrated to cable parts close to the electrode. Continued investigations have shown that for instance at 860 A , in the power electrode the increase of cable sheet potentials t range from 115 nV inland to 340 mV in the vicinity of the shoreline, giving corrosion potentials of -d400 mV and -100 mV respectively referred to CuSO ‘4 electrodes. To offset such potential changes cathodic protection consisting of rectifiers with potential regulation have been installed in three locations whereby the leakage currents in the cables are forced to ground via electrodes at the shoreline. Draining of the leakage currents from the cables, without the installation of rectifiers, has been found not to be sufficient in this case. Two cathodic protections have been in operation since 1971, the third from 1974. The average rate of corrosion failures have been reduced remarkably in the area. No secondary action from the cathodic protection on other buried structures has been explored during the investigations. Sardinia No report on corrosion has been received. Vancouver No corrosion has been reported (73-02-05). _ Pacific Intertie Sylmar No corrosion has been reported (74-07-26). Gelilo aot 7 No corrosion has been reported (72-08-23). 142 ¢ 7 2 LAE 75-08-C Diwee * Miveseine® band Stir 1. e conditions Aalborg Goteborg Water resistivity 20 oha ca 20 cha on Naat Soil restativity jooobaadoot-****0eeadooaal | apparent 200-500 oha ca J\. assis, surface 100-1000 ohe ca Soil moisture content 100%, partly saline water Soil quality 0-1 = depth: Beach sand I-approx. 200 mi: Reese a ee Glacial deposite: Blue clay, Gogg beamumeeny or sand, moraine, etc. Approx, 200-400 a: . e = a ee = Chalk, lime, thin layers of marl Approx. 400-1500 a: . Layers of sand, clay, hard clay etc. : plostic tube trom Stage potertaity arounel ehectooe 74 Below approx. 1500 a: sot “eal Ane zn = k Bed-rock, probably gneiss for conmall Tesouet ~N 2. Electrode design cable wilh tonga-inatruments : seq level Polarity A c - \ Type Shore Sea The ratereca O tat. \ da tha peteatial of the Electrode units Le Hlogging eel sacs thors he os \ fuaber 25 1 ~~ ‘i material Impregnated graphite Bare copper egnduct 7 \ \ dimensions L 2440 ma, 6 100 ma 300 =, 600 ae 0 mm \ p ~? Electrode units housing | Trenches None Eoch grophite clcctrede ts embsdied Ia | % ie | \ material Coke filling 35 mm? of cotie. Col:e typa: Neavy furnace | Y; Ce | grain size 40-50 an cos en re Oe a ' 4 G | perforation at ww / dimension Cross section taxia . : / Depth of electrode centre 1.1 0 Conductor arranged s ot , aa) Arrangement Horizontal, linear on beach in a ring on sea bed} el / at 10-15 = depth The bovier (Doyen od) ow 7. about 3000 « of fshor fogging Is laid dupctly ji 4 Calculated r. ance 0.02 ohe Y ‘on the coke-bad surface. a Measured resistance 0.02 ohe — 5 3 “ “ The upper ket of Meg9- b ‘ is told tinded with a i aioe fuse ts ted KONTI-SKAN guss-lee lacad ond Aalborg electrode after nee rebuilding 1968-1971 T7e 1, Site conditions Radisson Resistivity sounding ohe ca Soil quality and resietivity Silty till (Two values given Paleeozoice for measurement or overburden at two axes) Palasoroice or overburden} (In one axi Rocke to the sides Soil solature content, Water table Linited Situation fe poor Incidence of persafrost 2. Electrode design Polarity Aec Type land Electrode unite nuaber One ring material Steel rods, cadwelded end-to-end dimensions rod 61 1/2" ring ® 1250' Electrode unit housing waterial Low Sulphur content coke filling dimensions Trench cross section 2'x2' Depth of elec trode centre approx 9! Arrangesents Horizontally,circuler arrangement in ground surface Calculated reaistance 0,4 cha (0,38) Mesaured resistance 0,4 ohe Porous eacarnnn = __ | A) boca Tkmocourkts 164n Bn 40.3» CART Bate Gu A ‘ . y oo ARCA. TVPICAL THEmsOCOUrLE TERM BOK HO.2 —y 10 9€ Locar mont TOR THE HIGHEST SPOT IM THUS Ect iON. a mor stuRe wae ~motstuae Tues, AME AMQCOUPLES TEM pox no G 10 OC Locateo 10 MONLIOR THe MIGHEST SO tm MHtS SECTION A monetary [_ = Semuocourees VER OH HO. war \ - 5 if worstuRt ruet 1CAL). SEE NOTE . : MecmMOCOUFLES 1m BOANO! 4 Were, + hee Ss = SuAvEY LUNES — wor stuhe THEAMOCOURLES TEAM twat 80x WO. 6 10 af To MOvhTOR THE MiG ae SeOr iy maid SECTION woistuar rust SECTION Darmwocouries 10 ci) pamocourice sea acer’ oacerine hy NELSON RIVER # a Radisson electrode station A » S¥T 1, Site conditions Soil quality and resietivity (Teo values given for measurement at two axes) Soll molature content, Water table Electrode design Polerity Type Electrode unite nuaber moterial dimensions rod ring Electrode unit housing material dimensions Arrangeaents Calculated resistence Measured resistance Rosletivity sounding ohe ca 5400-6000 }1,40-1,43 73000-65000 | 140-1507 Precasbrian Linited No free water table down to 4,5 0 One ring Steel rode, cadwelded end-to-end 81 1/2" ® 800" Low Sulphur content coke filling Trench cr section 2'x2' Depth of elec- trode centre approx 9! Horizontally,cirouler arrangement in ground surface 0,4 oha (0,38) 0,4 oha Tani pave quit” ACPOSS OAAINAdE atce vi : IMERMOCOUPLES TERM 80K WO. 1 ‘S000 POST A, THe moc OurLE Tend 00x WO.8 - tint * Twtamocourl & Teh BOX WO.4 h- Nworstume wat DY i Tacemocours ch \ 5 tome B64 HO.3 He a) KP URTURE CaTENSION FT ELECTRODE ’ REQUIALS CONVERTING FOR CURMLAT CAPACHTY OF 4 MONTH CONTINUOUS OFERATION. meta Gran NELSON RIVER : Dorsey electrode station a LL smetg aN (wal) | cor NZED ELSAM ENEL (PCR) ENEL (PCR) BCH 8CH SPA Gotland, Vistervik Get land, Visby Cross Channel Lydd Cross Channel Echinghen Velgograd-Oonbass Volzhaskaya : Velgograd-Jonbas Mikhad lovekaya Cook-Strait Bemore CookeStrait Konti-Skan Aalborg Konti-Skan Gothenourg Sardinia,Sardinia Sardinia,Main land Vancouver Island Vancouver Mainland! Pacific Intertie Celile I (and II) Pacific Intertie Sylmar 1954 1961 1961 1962 1962 1965 1965 1965 1965 1965 1966 1966 1968 1968 1970 1970 A+c Aec Ac aed Ac Ae 146 8 1200 1200 4000 1000 1000 1000 1200 1200 1800 1800 Bipolar polar 23/oor= wally Sipolar 1006rief Fig. Fig. Fige Fige Fige Fig. Fige Fig. Fig. Fig. Fige Figs 20,4 |1974 Mostly {8 Mah of} | ich 1962 6.7 Mah to in one 1968 pole ration 6.9 [April 1965 12.1 to July 1974 12.1 6.9 , %.6 = |[/May 1965 to January %.6 = |}1974 2 Dec 1966 pto Fear. 2 1969 22-26 Feo. 1968 30 August 4 22-26 1972 0,047 0,045 0,28 Jan. 1970 (to July 0,047 1974 0,048 0,26 ¥ Revised Aug. 1975 Bipelar cable only Common earth return for two 1800 4 transmissions Values limited due to availibi lity of sonopal: metallic return Unbalance curre [S204 in bipolar operation. Utility cess Mozasbiqu Escos 8CH Tri-State Basin Elecr Power C. Sismarc Visby Eel River Nelson River Radisson (North) Nelson River Dorsey (South) Kingsnorth Cabora Sessa Cabora Gassa Cabora Sassa Apolo Vancouver V Jaland Terminal Vancouver Arnott Stegall Seottb luff 1972 1972= 1978 1972— 1978 1973 1973 1975 1976 1976 1976 Ne Land} A+C Land| A+C Ne land | A+C land | A+C No 147 1800 1800 1200 1800 1800 1200 1200 Bipolar | Figs ita 100/brisf} periods to 4 weeks ‘mally Bipolar | Fige ib 100/or inf periods to 4 weaks + S/nors wally Max 11004 100/on unoa lane: Max 11 want unba lane: Page 2 UE 75-09-02 Jan, 1973 to Aug. 1975 (may Bipolar and monopolar with cable neutral for current balance and re- turn respective Extension, No change of elec- trodes, Additio al pole 13204 1700A) .Metalli return up to 6C unbalance curr One station frequency converter = A ay Zaire Kolwezi CU Project USA Coal Creek CU Project USA Oickinsen 1977 197 T= 197 T= 1978 1978 TABLE f i 9 Electrode design Aec Aec 148 1000 (560) 1120 (360) 1120 10 1250 100/ 200/100 200/100 | Pace 3 TABLE Approximate distance (km) from electrode to buried structures Be 8 Vdaters vik Pipeline P Distribution pipes | °6 gas Oistribution pipes PL liquid Cables Plastic coated oO 0,5 ( *> distr. or tele 7 . | Telecoas, ce Distr. <10 W co _ \ Transe.> 10 kV cT Submarine cts 12 Metallic structure “ Arsouring - Ma a7, Railroad mR Storage tanks MS Steel tower ut “= Tranaformer directly! T ‘Dy sounded Distribution m | 2,2 (77 Tranamiasion 7 | 47 ar \ Urban area U > 1000 peopie 17,5 = corroded “corroded prior to finstallation [ Jeathodic protectiqn (wal) 0,5 10 10 10 10 10 of ca >9 odic (s] | 7» 6 6 9 7 0,6 1 9 6 ction 149 13 0,6 75 0,8 0,8 0,6 12 10 10 10 10 10 10 aeons ee eee Besser org atm Sare a ‘anc. |Main- Colilesy lear ward: rae org Gath dini Island! land 11 10 10 10 Page 1 UE 75-09-02 a [29] (ti | 11,5 s 1 a 10,9 12 11,5 9 6 11,5 | 4 [19 4,8 10,7 | 12 11,5 6,4 11,0 1,5 | 4 9 4 11 9 3 11,5 Pacific Revised August 1975 Puse* shor eiex 1€c> 1.3) 3.3 0,2 TASLE 2°. Page 2 paige Approximate distance (ks) from electrode to buried structures ULE 75-0902 ' ie femme occ are eae eset create Sey in dia- Radis= pr ee Spee Pipeline i x “ Distribution pipes PG 2 gas Distribution pipes PL 2 liquid : Cables . Cc Plastic coated oe ‘ distr, or tele ( . | Telécoas, cc j | Distr. <10 W - % Transm. > 10 WV ct Subsarine Metallic structure ” Arsouring « + ma | 8,8 20 Railroad wm | 2,4 4 : 6,4 3 Storage tanks Steel tower i ” Teansforner directly} T 1(9 grounded Distribution 1 0,8 ( Transsission Tv j~20 Urban area U => 1000 people 22 = corroded I: am corroded prior to |inetallation lof cathodic protect c []eatheaie peotectian 1 1 (wal) 150 Reference i ; 14-69 (SC) 42 Second Supplement to cy A SURVEY OF CORROSION ASPECTS RELATED TO THE OPERATION OF ELECTRODES FOR HVDG GROUND RETURN A report to Study Committee No. 36 (Interference) (Volgograd 1969) by - Ingvar Lidén and Heine MArtensson ASEA, LUDVIKA Sweden (wat) 151 LAB 77-05-25 1. CONTENTS Summary 1. Presentation of projects, electrode design 2 and electrode operation 2. Measures taken to prevent corrosion on buried structures s( # 2.1 Selection of electrode site ~ 2.2 Distances to buried objects 2.3 Other measures for protection of specific objects 3. Experienced corrosion Conclusion Ne (- xX 152 Summary This Second Supplement is an additional updating of the original survey. The subjects covered are: new installations change of electrode design currents conducted through the electrodes measures to prevent corrosion experience or none-experience of corrosion to the extent such aspects have been reported. \ Totally twenty-two HVDC electrode stations have been energized and four are under installation. One electrode r station has been rebuilt from cathode to combined anode C and cathode design due to extension from monopolar to bi-polar system. Corrosion has been observed in two cases. Installation of fence insulators in one case and installation of cathodic protection in the other appears to be effective. To simplify the reference to the original report the original index of chapters has been used also in this revision. 153 3. 1. Presentation of projects electrode design and electrode operation. 1.1 No new HVDC transmissions are to be reported in Table 1. 1.2 Electrode design Cook-Strait North Island Shore Electrode Station The original graphite electrodes were removed from service on 1 October 1976 after operating for a total of 23.9 million amperes hours since commissioning in early 1965. The electrodes had by then become very fragile to handle as a result of the loss of graphite over the 11% years of operation. - X\ Silicon-irm electrodes were used to replace the graphite electrodes as new graphite electrodes could not be obtained. tT Although the new electrode station resistance with silicon- . iron electrodes installed was calculated to be about 24% higher than the original graphite installation, it is possible that the final resistance of the graphite installation imme- diately prior to replacement would have been higher than the new silicon-iron installation. However, the total earth return path resistance would be only increased 7% for a 24% increase in shore electrode station resistance. Vancouver The HVDC link will be extended with one additional pole, Pole II, rated -280 kV, 1320 A with a winter overload rating - of 1700 A. The first valve group of Pole II was put into = commercial service early 1977. The second group is scheduled for service in 1978. Ce The electrodes on Vancouver Island and the mainland (Boundary Bay) will now both be required to perform as an anode or cathod The Vancouver Island electrode will have a maximum current of 1320 A while operating as an anode and 1700 A as a cathode, The values for the mainland electrode are reversed. No changes have been made to the Vancouver Island electrode. - Major changes have been made to the mainland electrode which up to the time the system became bi-polar was required only to operate as a cathode. The changes made were as follows: a) The electrode was enlarged slightly to consist of 46 elec- trode bars instead of 40 as shown in rig. 7a. oN Pacific Sylmar Intertie 4. b) ‘The copper-weld ground rods were removed and replaced by Durichlor 51 bars which are made of a high silicon iron alloy. c) The Durichlor bars were installed as shown in Fig. 7a. The bars surrounded by a cylinder of high carbon content coke breeze are buried in the silt. The augered holes are capped with 1# feet of crushed rock to act as a vent for gases generated by the electrolysis action. In addition a PVC tube was slipped over the lead connection down to the top of the bar for further venting. a) The cable lead insulation chosen to withstand the highly chemical adverse environment generated by electrolysis consists of 3 different layers. First there is an extruded layer of "Halar" (a fluropolymer) adjacent to the conductor than a layer of high molecular weight polyethylene and lastly an outer shell of shrunk on teflon. e) Two out of the 46 electrode bars installed are made of graphite. These were installed to assess the long term performance of graphite compared to durichlor. The Sylmar ocean electrode continues to function without any design changes. Difficulties have been experienced with the polyethylene jacketed ocean cables due to damage from anchors and from abrasion on the ocean bottom. A new third cable was installed completely trenched in on the ocean bottom in February 1973, to replace one of the two original cables. This new cable has not incurred any damage. At no time were both cables damages simultaneously so that the electrode could not function. E55) ~ = Skagerrak CU Project 1.3 Electrode operation 5. The Danish electrode is a shore electrode consisting of coke embedded. graphite-electrode units. Fig. 13. An original installation of 20 electrode units gave a measured resistance of 0.6 ohm. By installation of 21 edditional electrode units as close as possible to the shore line the measured resistance was limited to 0.28 ohm. Additional measurements of equipotential lines and step-voltages will be performed during 1977, and reported later. The rated current of the transmission is 1000 A. The Norwegian electrode is a sea electrode. The original installation comprised 30 electrode units, Fig. 14, each consisting of one graphite electrode embedded in compres- sed coke in wooden containers. The containers are buried in the sea bottom and covered by a 20 cm thick layers as frost protection. Measurements on the complete electrode have given a 225 V potential rise at rated current 1000 A. These measurements have also confirmed the equivipotential lines derived during the operation of three test electrodes. However, the current distribution was not sufficiently even in that the units at the bay entrance carried each a relatively big share of the current. Electrode no. 30 carried around 10% and electrodes no. 21-30 around 65% of the total current. The salt content of the water can be 3% higher there than at the electrodes towards the inner part of the bay. The current distribution has been successfully improved in that an "artificial" potential line has been arranged by an aluminum conductor connected to ground rods along the electrodes and by addition of two electrodes at the electrode close to the bay entrance. The Dickinson and Coal Creek land electrodes are both planned to consist of 18 vertical electrodes each approximately 12 inches in diameter and approximately 200 feet in depth, see Fig. 15. The resistance of the electrode is calculated to be less than 0.1 ohm. The Mega-Ampere-hours (MAh) conducted through the electrodes, specified in Table 1 are updated. 156 ah 2 Measures taken to prevent corrosion on buried structures 2.1 Selection of electrode site Design criteria Skagerrak Pacific Intertie An estimate, taking normal safety precautions in account, has shown that the electrode station shall be placed at a minimum distance of 4 km from the transmission cable and minimum 1.5 km from metal objects with an extension ex- ceeding 100 m radial to the electrode, such as armoured cables and long pipelines. Two alternative electrode sites were selected for conside- vation. A test electrode arranged at the inner part of Alefjaersfjord clearly showed that the stray current den- s sity was unacceptable with regard to the risk for corrosion on telephone cables and other installations in the Kjevik- Varoddbroen area and in the Kristiansand harbour. The test clearly showed that the electrode had to be located as far as possible towards the open sea. rT The electrode was installed at the alternative site in a bay with shallow water close to the open sea. Measure— ments on three parallel test electrodes indicated a potential rise above "true ground" of approximately 200 V at 1000 A corresponding to a resistance of 0.2 ohms to "true ground". At the time of energization of the Pacific D-C Intertie there was an agreement between the Intertie operators and the in- volved gas pipeline people that ground return operation of the Intertie would be limited to 144,000 Ampere hours per year. This figure was arrived at by assuming full load current operation of 1800 A for 80 hours total per year. The actual record of the monopolar operation with ground return is as follows: = Year Total Ampere Hours 1972 6,906 1973 11,055 1974 12,850 1975 5,534 1976 (through July 1) __8.043 44,3638 157 FN 2.3 7. As can be seen from the record the total ampere hours for 4s years is only 44,388. Despite this record the present policy is to limit ground return operation to 15 min during any single fault condition. There is now capability to operate metallic return for times longer than 15 min. The unenergized pole is used for the metallic return path, unless of course the fault is caused by loss of one conductor. Since most faults are terminal faults ground return operation from July 1976 to the present time will not significantly add to” the total shown above. = Normal bipolar unbalance current was specified as + 3% of the full 1800 A load.current or 54 A. Records show that unbalance currents rarely exceed 10 A for this line. Other measures for protection of buried objects . Cook Strait Vancouver A fence with seven galvanised wires on impregnated timber posts in 5 metres average distance to the electrode line has been provided with small insulators in the wires at main posts and at 20 metre intervals in between (See chapter 3). In May 1975 an interim metallic return circuit consisting of two spare cables was put into service. This resulted in Pole I operating as a +260 kV, 1200 A monopolar system with no ground return current. In this mode of operation the VIT converter “station was operated grounded as the reference while Arnott was ungrounded. This configuration was used almost continu- ously from May 1975 to October 1975 and then on an inter- mittent basis during the winter peak load of 1975 and also during the construction and installation period of Pole II in 1976. During normal bi-polar operation of the Pole I and Pole II the system will operate with a metallic return circuit (1 spare dc cable) which is capable of carrying unbalanced currents up to 600 A. During extended periods of monopolar operation the " system will also be able to operate with a metallic return using the cables of the pole whose converter equipment is down for servicing. During metallic return operation the Arnott converter station will be operated grounded as the reference. 158 8. Whenever the system uses a ground return during bi-polar opetation, pole balancing of the current orders will be used when possible to minimize the magnitude of the ground current. The decision to use a metallic return path to eliminate ground return current or alternatively to minimize it by pole balancin of the current orders is aimed at avoiding interference problem the potential for which is steadily increasing as the number of buried facilities in proximity to the electrode increases. A cathodic protection system has been installed to protect a sewer pipe line (See chapter 3 below). 3 Experienced corrosion Gotland No further corrosion has been mentioned in report 77-03-23. Volgograd—-Donbass No report on corrosion has been received. Cook-Strait In June 1976 a post and wire fence, comprising seven runs of galvanised wire supported on timber posts which had been treated with a water borne multi-metallic salt preservative, was erected parallel to the electrode line and terminating adjacent to the electrode site. The spacing between the © electrode line and the fence averaged 5 metres. During erection of the fence the farmer reported sparking between - ( the fence wires and metallic items brought into contact with C it. Within a few weeks corrosion was obvious at the points where the lowest wire was attached by metal staples to the posts, and also at all positions where the wire was in contact with the ground. Signs of corrosion existed over about 400 metres of fence length. A current of 80 mA was measured in the lowest fence wire. Further corrosion was prevented by inserting small insulators in the fence wires at main posts and at 20 metre intervals in between. ' 159 9. Konti-Skan No corrosion damages have been revealed round the Aalborg electrode station, 77-03-25. ( No further corrosion at the Gothenburg electrode is reported 17-03-23. Vancouver Questions have been raised as to the effect that the HVDC grounc current has had on a sewer pipe-line. The sewer line was originally installed without a proper insulation coating and cathodic protection. Subsequent to the corrosion problems arising a cathodic protection system has been installed and - appears to be effective. Pacific Intertie No corrosion problems due to de:stray current from this system have been reported to date. The Utilities are therefore satisfied with the adequacy of the design of the earth and sea electrodes and the separation distances established between the electrodes and major buried metallic systems. Continuous monitoring of certain pipelines and telephone cable is still being carried on by some companies having underground plants near the Sylmar electrode. C Nelson River Nothing new to report 77-04-13. 160 Specification 1a Literature It may be reminded that the original report as well as any supplements to the report are intended as surveys only. The reader who is interested in detailed information in any specific matter is referred to the basic information available with the Utilities referred to in the report. Further reference is given to the following literature. /12/ Proceedings Manitoba Power Conference EHV-DC Winnipeg Canada, June 7-10 1971. /13/ & Unlmann, Power Transmission by Direct Current. Springer-Verlag, Berlin Heidelberg New York 1975. /14/ C.I.G.R.E. Study Committee 14, October 1975, Johannesburg by F.W. Cors "Report on the Equipment of the Cabora Bassa Scheme - The Earth Electrodes - /15/ The CU HVDC Transmission System Cigré Study Committee 14 Colloquium, Winnipeg,June 1977. 161 al! KZo £°D2 " in b Acer Got land, Vistervik Get land, Visby Cross Channel lyss Cross Channel | Echinghen HY | Velgograd-Jonbass ! volznaskays : volgograce-Jondas “iknailovskaya foomeSsrais wiyeaccs Sakura saisors Kont i<Skan Sethendurg Sarcinia,Sarcinia Sardinia, Yainlane Vancouver Island Foie 2 Vancouver Mainland: Facific Intertie Celile 1 {ane 11) Sy lear 1954 1964 1961 1962 1962 1965 1966 1968 1968 1970 | 1970 e Land land 'Usne he Land ‘Sea oa o aed 8 1000 1000 1000 1200 1200 1800 1800 162 Bipolar and polar Bipolar and polar 100/ lono- perioes polar 100/ 100 Yonoe polar 100/100 polar 100/100 Bipolar 200/bris* period, o3/nor= lly | Bipolar | [10Gbref | \perios, | 2 Vner| jmaity Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fio. 4 c 3.0 = [1977 . Bipolar cable only 10 }Mostly |6 Mah of| \ A |which | 1962 6.7 Man | to 10 |Mestly|in one e 1968 C pele ope= | ration } h Z 4 | S68. |Mpril 1965 c | 12.1 [fee uly ¥1S74 23.9 Total to Oct 1976 Sf A | a2 is 1985 ti ¢ 6.2 [tg uly 23.9 1 Oct 1976 t fOne-atation | ' frequency | eonverter emia 41,0 | May 1965 | Sto March aa) 5 4120 yaar 5 a 2 'Dee 1966 bee Feber. s ¢ 2 1969 6 A | 22-25 [}Febr, 1968 re August vi C 4 22-26 |}1972 Ea ||| foucaem: itso Soro 0) 01) es jt 0.054 ee Exclusive of b ie normal unbdalanc: P)aec | 0.26 eae currents. — | 197% ; Values limiteo fi due to availibi L fA | 0.054 ian 4970 | lity of monceol to li $ | ue | 0.058 tere etallic return | var 175 [2ibeS | 0,25 | Te July |unbalance curs 1976 trarely exceecin }10 4 in bipolar operation Mezaabique Escos BCH TriState | Basin Elecr Scotts luff Nelson River Radisson (North) Nelson River Dorsey (South) ¥inesnorth Cabora Bassa Cabora Bassa Cabora Sassa Apolo Vancouver Pole if Vancouver Arnott Stegall Pole IT 1972= 1978 1972= 1978 1975 1978 1975 4877-78 1977-78 1976 TABLE land Land | No i § Shore Shore! No 4 1800 1800 4200 1800 1800 Max. curr, |A1S20 1700 |A1700 C1320 163 Bipolar | Fig. ita 100/briaf| periods to 4 weeks + 5/nore| wally Bipolar | Fig. 11> 100/be ief, periods to 4 weexs + S/nor= lly 400/Limi ted geri rope ig 7a ted peri Page 2 UE 75.09.02. Bipolar and monopolar with cable neutral for current Arnot electrode rebuilt. © Metallic return up to 600A une balance current and on extended monopolar opera. tion, One station frecuency converter Tjele WE Skagerack Kristiansand Minketa Square Butte Power Center Cooperative Square Butte Duluth SHEL Zaire Inga SNEL Zaire Kolwezi CPA - CU Project USA Coal Creek. UPA CU Project USA Dickinson Rev. May 1977 1977 1976= 1977 1977 1977 1977 = 1978 1978 Shorq A + C Sea {A +C Land Land | Land Land land | A+C land | AoC 164 1000 1000 1000 1000 (360) 1120 (360) 1120 1250 1250 % tise 100/ 100/ 200/100 200/100 Fig 15 ELSAM Skagerack 1976— a3 | from Aug 74 cable return : from Aug 77 Site conditions Water resistivity Soil resistivity epparent surface depth Soil moisture content Soil quality * Electrode desion Polarity Type Electrode units nurber material dimensions Electrode unit housing waterial perforation dimensions Arrangerent Calculated resistance Measured resistance . 32 1) Replaced by silicon-iron electrodes 1976 2) Calculated silicon-iron electrode resistance about Revised May 1977 H oO uw a, ote “) 4 ELECTRODE LIN: ‘ . TERMINAL POLE. ¥ . 1 ° Switch House ; ‘ | os ‘FINAL BEACH LEVEL 1000 ohm cm< 10! water fl ; . saturated shingle \\e iranian 3 BOULDER LAYER TEMPORARY , as - 20-0" STOPBANK . 100000 ohm cm rock 1F-Q we 4 a i 41-75 HIGHEST. HIGH WATER LEVEL aes oe coi Sa 0 ban : - , TURE TION Ky ~—~— PS tame SR 10’ MEAN HIGH WATER LEVEL . AEA fe IMPERVIOUS \ £9 MEAN SEA LEVEL SGEW PIPES u LAYER 2:9 HEAN LOW WATER LEVEL SET IN CONCRETE |L ize. } 9 CUT OFF DRAIN LOW WATER 8-7 LOWEST Low WATER LEVEL , “ol TO suMPS MARK Se, 8. + a orc — EE, ALERS . 17 10__ 25 Impregnated graphite L7, po" 1) Concrete pipe 6% te, o2t Vertical in backfilled beach trench drained by water tide 0,18 ohm 0,23-0.3 ohm 2) 668-0 aa xp MITCH HOUSE _,_ JUNCTION PITS a7 iS CONERETE pire TTT. . 24% higher. pit fi ' Lith yay Lt ] 3 SPO A ra / : i SeH oe > LIFTS OF TRENCH : rs ype fa tittgrie FENCE TEMPORARY STOPBANK” Beach Surface Potential Map. Percentage of full electrode Voltage drop to remote earth, APPROX. Ly __ — — a tine Sea electrode final layouts, N.Z.E.D. NORTH (SLAND SEA ELECTRODE, Site condi tons Water rosistivily Soil resistivity apparent surfece depth Soil moisture content Soil quality + Electrode design Polerity Type Electrode units number material dimensions Electrode unit housing material perforation dimensions Arrangement Calculated resistence Measured resistance oT See igure 7 A+ Shore 4442 44 high silicon iron alloy 2 graphite aq" Coke Crushed rock ventilation 132" fers in coke breeze buried in silt, err i f Sang ye mi #3SW ELS #isw end 1,24n03 #5sw ELS # ASW ELA 44,45 1046 EXTENSION 447 EXTENSION =f L Wl © CURICHLOR SI TA-5 BARS BURIED IN COKE BREEZE et 10% 45 @ CELLS #1 AND # 46 - GRAPHITE THERMOCOUPLES LASHED Ot 70 BAAS FOR CELL HI AND J2 aa 87 Trricac ELecrrobe BAR INSTALLATION B.Hyoro MAINLAND Electrode el sam2ty 1, Site conditions Water resistivity Soil resistivity epperent surface depth Soil moisture content Soil quality 2, Electrode design Polarity Type Etectrode units number material dimensions Electrode unit housing material perforation dimensions Arrangement Calculated resistance. Measured resistance IT A+c Shore a Graphite {in——~ Coke in concrete wellring Electrodes installed at approx, 2 m depth 0.28 ohm ra ge Approximate scale ice ne ee Renee A eee 0 8 th % 32 40m NH Se SIE SIC alls LEO EER GG, LOVNS BREDNING Elektrode station Graphite - bar ! (Electrode) ELSAM CL exattr « Sile condition: Water resistivity fialt content Soil resi-tivily apparent surface depth Soil moisture content Soil quality '» Electrode design Polarity Type Electrode units number material dimensions Flectrode unit housing material perforation dimensions Arrangement Calculated resistance Measured resistance 3% normally, 1,9 % wt heavy rain foll Ase Sea 30 & 2) Graphite Rod 120 cmX10,5 one Coke in wooden case see figure 300100100 Cases buried in sea bed 0,2 ohm 0,225 obm 89T “y sae G# Plante tube with 30 cobles Located Into the sea bed - 2" holon for each cablo branch-off “tio 05a “phtated bbbE BLE BEE fb B “ eonnemnnnvdeens , | Container of F ‘an wood | ll “_e _ da Ci lil [ two HWOAONK A SUUUUUUUULOUUUU 9 <J 300m Speo cable protected Ath plastic tube Conorete An epoxy cobtng - coke Paper-board eleeve with coke will be fixed to the electrode when lowered ° —~ Graphite rod 120 x 10,5 ont Section: B-H Skagorack Norwogian Blootrode PL ema Gravel Backfill Earth's Surface Plastic 750 KCNIT. Tnsulated —Underground Cable. 4/0 Insulated Underground Cable Electrode . Rod tee Casing ze Section A-A fr (200 £2) Jad Electrode Distritution Rod | (6 rods per electrode) , Centering S8races 1 — v LLL |e Plugged Bottom L/Im = (2s Ee) Single vertic2l ground electrode 169 oy CU BVDC THzNSMiSS=IO% APPENDIX C LETTER FROM SIGUARD SMEDSFELT TO MS. JAN MILLS RE SWEDISH TESTS ON THE INFLUENCE OF THE MARINE FAUNA FROM ELECTRIC CURRENTS IN THE WATER. 170 O38 we BT " Our attention S Smedsfelt STATENS VATTENFALLSVERK THE SWEDISH STATE POWER BOARD Our date Our ret 1981-10-02 ET-St/AA Your date Your ref Environaid Janice Mills 360 Distin Avenue JUNEAU, Alaska 99801 USA Dear Mrs Mills, Thanks for your letter of September 2. In 1948-1949 we carried out extensive tests on the influence of the marine fauna from electric current in the water. We also published a report on the tests. I have, however, just exchanged the furniture in my room and I have not been able to find the copies left. I enclose, however, a summary of the report describing the main results. You will note that the electrodes have to be protected in some way so that fish cannot come too close to them. That is necess- ary for both electrodes if they are used as anodes some time and as cathodes some time. If the direction of the current is always the same, which means that one of the electrodes always operates as anode and the other one as cathode, it is sufficient to protect only the anode station. At the cathode no protection is necessary because the fish is repelled from it. The cathode can then be made of a single copper wire placed on the sea bottom. This has been used in Sweden since 1954. If I find the full report I will send you a copy. Kindest regards, Yours sincerely, Fis 2 A 71. Telephone ieee The Electrical Current's Impact on Sea Fauna During the first two stages of the Gotland-transmission the seawater will be used as currentreturn at 200A. As this current might have an impact on sea fauna, the Swedish State Power Board and the National Board of Fishery made in 1949 extensive investigations at Vdstervik with fishes and invertebrates. A direct current of 200A was transmitted about 1 km between two electrodes during four weeks. The bottom fauna was examined before, during and after the test, and the number of specimens of different species was determined. No reduction was established that could be attributed to the impact of the current. On one occasion, however, electrolytic production of ferrie hydroxide caused considerable damages on the bottom fauna. This can be avoided by using proper electrode material. During the long-time experiments with fishes (pike, cod, perch, eel, bream, roach, herring) kept in cages 4-10 m from the electrodes, no influence what so ever could be established neither at the anode nor at the cathode. Some "“fish-chest death" occurred of course. At a distance of 0 - 1,5 4 2 m from the electrodes the fishes were unconscious at the instant of current closing but recovered after current breaking. The fishes were always striving towards the anode and away from the cathode. No reaction what so ever could be noted at distances exceeding about 2,5 m. The effect on free shoals of fish was investigated with echo sounders but no reaction was observed. The concluding results from the investigations prove that the sea fauna is not affected by the electrical current provided proper remedies are ~ undertaken. The most important measure is to prevent the fishes to come close to the electrodes. This can be accomplished e g by surround- ing the electrodes with protective nets. (Translation from: Teknisk Tidskrift te Dec. 3, 1949 p. 923-924) APPENDIX D LETTER FROM MR. S.L. NILSSON, ELECTRIC POWER RESEARCH INSTITUTE RE LOCATION OF HVDC SUBMARINE CABLE SYSTEMS, NATURE, SCOPE OF EFFECTS. 78 -—{, ee we EEE CTRIG POWERIRESEAR CH UNS i] TUT Ee September 23, 1981 Mr. Donald L. Shira Chief, Planning Division Department of Energy Alaska Power Administration P. 0. Box 50 Juneau, Alaska 99802 Subject: Snettisham-Ketchikan DC Link Dear Mr. Shira: I will try to respond to the questions raised in your August 19, 198] letter to our Research Reports Center. While there may not be much documentation of environmental problems regarding electrodes, there is a wealth of information around the world about the operation of dc links. I will therefore try to give you information about possible contacts that may be of help. Sea electrodes are used for the following dc projects: Sweden - Gotland (monopolar) New Zealand Sardinia - Italy (monopolar) Sweden - Denmark (monopolar) Norway - Denmark Pacific HVDC Intertie Vancouver Island HVDC Link (monopolar from 1968 to 1975) N OO FP WH — The owners are the national utilities except for the Danish systems, which are owned by ELSAM in Denmark, and the Pacific Intertie that is owned by Bonneville Power Administration and the Department of Water and Power, City of Los Angeles. In general, the monopolar systems have elaborate anode electrodes but very simple cathode electrodes. The bipolar systems must be designed for both anode and cathode duties. Fish barriers/people protection has been used at the anode sites, whereas there normally is no or very little protection at the cathode sites. Corrosion of permanently installed structures such as sewer lines has been experienced. In general these problems have been manageable. Chlorine gas development that affected vegetation in a very small area at the electrode site has been reported by BC Hydro. Magnetic field effects were of major concern for the cross-channel link between England and France and in fact was one of the reasons for the selection of a two-cable system for that dc link. To my knowledge, it has 174 Io actacartaee, QA49 Hillviow Avenue. Post Office Box 10412, Palo Alto, CA 94303 (415) 855-2000 Mr. Donald L. Shira September 23, 1981 Page Two A been of no major concern in the other cases. The reason for this might | / have been different orientation of the cables in relationship to the { magnetic field of the earth. Let me point out two EPRI reports that may be of interest to you. One deals with multiterminal systems. This is report EL-1260, System Studies for HVDC Circuit Breakers. The other is a new report, EL-2020, HVDC Ground Electrode Design. You can order them from our Records and Reports Center. Please let me know if we can be of further assistance. Sincerely, (I ee 4s. Uahsson Project Manager Electrical Systems Division SLN:ek cc: J. Dunlap L75 APPENDIX E THE NATURAL MAGNETIC SETTING OF THE PROPOSED D.C. TRANSMISSION ROUTE 176 GENERAL The geomagnetic field along the proposed submarine DC transmission line route from Port Snettisham (near Juneau) to Ketchikan has an average total intensity between 57 and 58,000 nanotesla (.57 to .58 gauss), with a horizontal intensity of 15 to 16,000 nt (.15 to .16 G) and vertical intensity of 55 to 56,000 nt (.55 to .56 G). Normal declination for southeast Alaska ranges from 27 to 29°. NATURAL VARIABILITY Magnetic activity is directly related to sum spot activity, and the earth is presently coming off a peak of activity in the 11 year sun spot cycle. During large magnetic storms in southeast Alaska, the horizontal intensity (H) and vertical intensity (Z) of the earth's magnetic field often have ranges of 1000 nt (.0100 G) or more, and declination may change several degrees in a few hours (W. Osbakken, personal communication). During a principal 6 day magnetic storm beginning on May 10, 1981, values for H and Z ranged 1210 nt (.0120 G) and 410 nt (.0041 G), respectively, at the U.S.G.S. Sitka Observatory. The range of declination at the Sitka Observatory could not be measured for this event as the trace was off of the magnetograph record for a portion of the storm. However, compass headings can deviate by as much as 5 to 6° during a magnetic storm. Twenty principal magnetic storms have been recorded at the Sitka Observatory between January 1 and September 18, 1981. Disturbances of lesser magnitude commonly occur every few days in southeast Alaska. Although these events are not large enough to be classified as magnetic storms, the variability of H and Z values are significant (300 to 400 nt) for these occurrences. A third feature of normal variability is the diurnal curve or daily variation. Fields may range 90 nt (.0009 G) over a 24 hour period. Additional magnetic variability may be introduced due to the magnetic influence of local ore deposits or other geologic factors. The National Oceanic and 177 Atmospheric Administration map for "Stephens Passage to Cross Sound" (1:209,978) indicates that an area of extreme magnetic disturbance exists in Port Snettisham and Gilbert Bay. Natural extreme declinations (78°) make the magnetic compass entirely unreliable in this zone. 178 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY Sitka Observatory Box 158 Sitka, Alaska 99835 September 18, 1981 Ms. Jan Mills 360 Distin Avenue Juneau, Alaska 99801 * Dear Ms. Mills: I have enclosed several days of magnetograph recordings from the Sitka Observatory in hopes of illustrating some of the magnetic field changes that take place at this latitude and to answer your questions in your letter of September llth. The facilities for making copies of my records here are primative and result in a reversed print, that is, white traces on a black background but they are legible for the most part. As you no doubt are aware, magnetic activity is directly related to sun spot activity. We are at present coming off of a peak of activity in the 11 year sun spot cycle. My records are forwarded to Denver on a monthly basis so I did not have an intense magnetic storm to illustrate. During a large storm the horizontal intensity (H) and the vertical intensity (Z) often have ranges of 1000 nt or more. Declination may change several degrees in afew hours. During a principal magnetic storm beginning on May 10th this year H and Z ranged 1210 and 410 nt respect- ively. I was unable to measure the range of declination (D) as the trace was off of the magnetograph record for a portion of the storm. This storm lasted for six days. Thus far this year there have been 20 principal magnetic storms. The small disturbance that you see on Sept. 2nd is much more common and events of this magnitude occur every few days. We have had 4 similar events so far this month. though these events are not large enough to be classified as magnetic storms it is obvious that the ranges for H and Z greatly exceed the values of annual change that you derived from the maps that I furnished. The change in nanoteslas may be found by miltiplying the appropriate scale value by the vevical shift in the trace measured in millimeters. For example, on Sept. and H changed 343 nt between points a and b and Z changed 468 nt between points c and d. Another feature that is noticable on the records is the diurnal curve or daily variation. It is especially obvious on the D and H traces of magnetically calm days such as Sept. lst and 7th. You will note that on Sept. lst the H field changed 88 nt between points x and z. 4 179 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY This daily variation is most pronounced during the summer months and least during the winter. Taking into account this daily variation and the typical events as shown on the sample magnetograms, I feel that it is safe to say that there are mee few days in the year when either H or Z does not exceed the annual changes referred to in your letter. I hope this information will be of some help to you in your project. : Sincerely, gt 7 » Nat lee MMe _ Willis Osbakken Chief, Sitka Observatory 180