IAEA-TECDOC-1075 XA9949696
Radioactivity in the Arctic Seas
Report for the International Arctic Seas Assessment Project (IASAP)
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INTERNATIONAL ATOMIC ENERGY AGENCA / Y / 1JrrziZr^AA
30-16 The originating Section of this publication in the IAEA was: Radiometrics Section International Atomic Energy Agency Marine Environment Laboratory B.P. 800 MC 98012 Monaco Cedex
RADIOACTIVITY IN THE ARCTIC SEAS IAEA, VIENNA, 1999 IAEA-TECDOC-1075 ISSN 1011-4289 ©IAEA, 1999 Printe IAEe th AustriAn y i d b a April 1999 FOREWORD
From 199 o 1993t e Internationa6th l Atomic Energy Agency's Marine Environment Laboratory (IAEA-MEL s engage IAEA'e wa ) th n di s International Arctic Seas Assessment Project (IASAP whicn i ) h emphasi bees ha sn place criticaa n do l revie f environmentawo l conditions in the Arctic Seas.
IAEA-MEe Th L programme, organize framewore th n dIASAi e th f ko P included:
(i) an oceanographic and an ecological description of the Arctic Seas; provisioe th (ii )centra a f no l database facilitIASAe th r yfo P programm collectione th r efo , synthesi interpretatiod san datf nmarino n ao e radioactivit Arctie th n yi c Seas;
(iii) participation in official expeditions to the Kara Sea organized by the joint Russian- Norwegian Experts Group (1992, 1993 and 1994), the Russian Academy of Sciences (1994), and the Naval Research Laboratory and Norwegian Defence Research Establishment (1995);
(iv) assistance wit d n laboratorsiti han u y based radiometric measurement f curreno s t radionuclide concentrations in the Kara Sea;
(v) organization of analytical quality assurance intercalibration exercises among the participating laboratories;
(vi) computer modellin e potentiath f o g l dispersa f radionuclideo l s released froe mth dumped f assessmeno wast d associatee ean th f o t d radiological consequencee th f o s disposals on local, regional and global scales;
(vii) in situ and laboratory based assessment of distribution coefficients (Kd) and concentration factor sArctie (CFth r c)fo environment.
This report summarize wore sth k done under parts (vii)(i)d resulte ,an (ii)Th ) . (v s, obtained under parts (iii), (iv) and (vi) have already been published in the scientific literature and the modelling components (vi) will also be included in a report of the Modelling and Assessment Working Group currently in preparation. The source term component of the IASA s beeha P n e Source treatereporth th f n o i etd Term Working Group, Predicted Radionuclide Release from Marine Reactors Dumped in the Kara Sea (IAEA-TECDOC-938 (1997)) presene Th . t report shoul reae d b conjunctio n di n wit maie hth n reporIASAe th f o tP project, Radiological Condition Westere th f so n Kar (Radiologicaa aSe l Assessment Reports Series, IAEA, Vienna (1998)) so that the full radiological context is appreciated.
This wor co-ordinates kwa IAEA'e th n di s Marine Environment Laborator Monacn yi o and the responsible officer was P.P. Povinec. The success of the project was due to the full collaboration of the institutions participating in the IASAP programme. The IAEA would like to expres gratituds sit Governmente th o et Germanyf so , Norway Russiae th , n Federatiod nan the United States of America for their generous support. The IAEA also extends its thanks to several institutions, namely the Norwegian Defence Research Establishment (Horten, Norway), the Norwegian Radiation Protection Authority (Osteras, Norway), SPA Typhoon (Obninsk, Russian Federation), the Murmansk Marine Biology Institute of the Russian Academy of Sciences (Murmansk, Russian Federation), the Arctic and Antarctic Research Institute (St. Petersburg, Russian Federation), MAFF (Lowestoft, United Kingdom) and others for their hel n providini p g radionuclide datd othean a r information necessare th r fo y completion of this report.
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EDITORIAL NOTE
In preparing this publication for press, staff of the IAEA have made up the pages from the original manuscripts). The views expressed do not necessarily reflect those of the IAEA, the governments of the nominating Member States or the nominating organizations. Throughout the text names of Member States are retained as they were when the text was compiled. The use of particular designations of countries or territories does not imply any judgement by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions delimitation ofthe or of their boundaries. The mention namesof specificof companies productsor (whetherindicatednot or as registered) does imply intentionnot any infringeto proprietary rights, should construednor be it as an endorsement or recommendation on the part of the IAEA. CONTENTS
SUMMARY...... 1
1. INTRODUCTION...... 3
2. DESCRIPTIO REGIOE TH F NNO ...... 4
2.1. Oceanography...... ^ 2.1.1. Arctic Ocean...... 4 2.1.2. Barents Sea...... 8 2.1.3. Kara Sea...... 9 2.1.4. Kar dumpsitea aSe s ...... 19 2.2. Ecology ...... 23 2.2.1. Biological productio Arctie th n i c ...... 23 2.2.2. Marine food-web Arctic...... 2e th n si 5 2.2.3. Fisfisheried hBarentan e th Karn d si san a Seas ...... 28
3. RADIOACTIVITY IN THE KARA SEA...... 29
3.1. Marine Radioactivity database...... 29 3.2. Pre-1992 radionuclide concentrations...... 30 3.2.1. Water...... 30 3.2.2. Sediment...... 33 3.3. Present radionuclide concentration Kare th an s i Sea...... 3 3 3.3.1. Dumpsites...... 33 opee 3.3.2Th n Kar. a Sea...... 45 Yenised an 3.3.3b O y .estuaries...... 4 6 3.3.4. Biota...... 46 3.3.5. Intercomparison exercises ...... 51 3.3.6. Conclusion radionuclidn so e inventorie Kar e ...... 5a th aSe n s i 1
4. DISTRIBUTION COEFFICIENTS AND CONCENTRATION FACTORS ...... 52
4.1. Distribution coefficients ...... 52 4.1.1. Result laboratorf so y experiments...... 53 4.1.2. Results of field experiments ...... 56 4.1.3. Conclusion distribution so n coefficients ...... 57 4.2. Concentration factors...... 57 4.2.1. 137 60d CCsan o transfer factor Arctir sfo c clams...... 58 4.2.2. Concentration factors for Arctic benthic organisms...... 58 4.2.3. Concentration factors for a Kara Sea bivalve...... 61 4.2.4. Conclusion concentration so n factors...... 62
5. CONCLUSIONS...... 64
REFERENCES ...... 65
CONTRIBUTORS TO DRAFTING AND REVIEW ...... 71 SUMMARY
From 199 199o 3t Internationae 6th l Atomic Energy Agency carrieInternationan a t dou l Arctic Seas Assessment Project (IASAP) in order to assess the consequences of the dumping of radioactive wastes in the Arctic Seas on human health and the environment. In the framewor f thio k s project IAEA'e th , s Marine Environment Laborator Monacn yi o (LAEA- MEL) has participated in several activities including the review of the oceanography and ecolog f Arctiyo c Seaassistind an s centraa s ga l e collectionfacilitth r yfo , synthesid an s interpretatio datf no marinn ao e radioactivit Arctie th yn i c Seas.
This report provides comprehensive information on environmental conditions in the Arctic Sea requires sa stud e th possiblf r yo d fo e radiological consequences from dumped high level radioactive waste Kare th an s i reporSea e Th . t describe oceanographe sth regionse th f yo , with emphasis on the Kara and Barents Seas, including the East Novaya Zemlya Fjords. The ecological description concentrate biologican so l production, marine food-web fisheried an s s in the Arctic Seas.
Further, IAEA-MEL, withi IASAe nth P programme bees ha , n actin centraa s ga l facility collectione foth r , synthesi interpretatiod an s f dat no marinn ao e radioactivit e Arctith n yi c Seas. The data have been included in the Global Marine Radioactivity Database (GLOMARD) whic bees hha n develope storo dt l dat emarinal n ao e radioactivit seawatern yi , sedimentd san biota database Th . e provides critical evaluatioe inputh o environmentae t th f no l radionuclide levels in the region and to the assessment of the radiation doses to local, regional and global human population marino t d san e biota. Concentration anthropogenif o s c radionuclidee th n si Kara and Barents Seas are studied over two time intervals — before and after 1992 — when new data, especially fro joine mth t Russian-Norwegian cruises, became availablee th n O . basis of data stored in the GLOMARD database on concentrations of several radionuclides in water, sedimen biotd an t a sample majoe th t rda dumpsite Abrosimove th n i s , Stepovod yan Tsivolka Fjords and the Novaya Zemlya Trough, as well as in the open Kara Sea and the Ob and Yenisey e concludeestuariesb n ca t i d, that, wite exceptioth h f limiteo n d arean i s Abrosimo d Stepovoan v y Fjords, only minor contamination exists relativ backgrouno t e d levels. The open Kara Sea is relatively uncontaminated, the main contributions being due to direct depositio catchmend nan t runoff from global fallout cause nucleay db r weapons tests, discharges from reprocessing plants in western Europe and the former Soviet Union, local fallout from tests performed at Novaya Zemlya and Chemobyl fallout.
The concept e distributioth f o s n coefficien e concentratiot th (Kd d )an n factor (CF) have been use intercomparo dt e relativeth e degree f uptako s f marino e e contaminanty b s different sediment type marind an s e biota, respectively. Laborator field yan d studies were carrie investigato t t dou environmentae eth l parameters that might affec valueF C t r d K According to the first available information [1] the dumping activities of the former e inventorth o t Sovie q f radionuclideyo PB t 0 Unio9 e added o t th nha p n i dstotaa u f o l marginal Arctic Seas, primaril nucleas ya r reactor assemblies (some including spent nuclear fuelentird an ) e vessel PBq9 (8 st als )s liquibu oa d (0.9 PBq). Considerin l wastgal e types, over 95% of the total activity of the nuclear material was located in the Kara Sea. No disposal f objecto s s with spent nuclear fuel were reporte Barente th r dfo s Sea, althouge hth nuclear-powered and armed submarine Komsomolets which sank accidentally in the Norwegia region'e th 198o n t i q a s9 inventoryn Se addPB 5 s5. . More recent estimate hav] 3 , es [2 suggeste d tha presene tth t inventorie radionuclidef so s r fissiofo ) n(a e Kar a ireactorproductsth ne b Se a n ca s , abou 1 PBq4. r t S , 137 d Can s respectivelyq e activatiocontributinPB th 9 r 0. fo d ) n(b an , productsg1 , abou PBq5 0. t e ,th 63 60 largest contribution being from Ni (0.3 PBq) and Co (0.1 PBq) and (c) for the actinides, 241 about 0.1 PBq (the highest contribution (0.08 PBq) being from Pu). From the point of view of the total activities in the disposed materials, Tsivolka Fjord is the dominant dump site (2.2 PBq), although Abrosimov and Stepovoy Fjords and the Novaya Zemlya Trough contain important inventorie fissiof so n product PBq3 0. sd , respectively)(1.4an 8 ,0. , while Techeniye Fjord hosts 0.005 PBq of activation products. dumpine Asth f higgo h level radioactive wastes took plac eKarae onlth n yi Seae ,th main interes stude th environmentaf yn o ti l condition bees sha n centre thin do s particular sea. However predictionr fo , possiblf so e environmental consequences from dumped wastes, other Arctic Seas have been under focus as well for a better understanding of the oceanography and ecolog regione th f yo . The International Atomic Energy Agency carrie t durindou g 1993-199 Internationan 6a l Arctic Seas Assessment Project (IASAP) in order to assess the consequences of the dumping f radioactivo e e wasteArctith n i cs Sea n humao s ne environment th healt d an he th n I . framework of this project, the IAEA's Marine Environment Laboratory in Monaco (IAEA- MEL) has participated in several activities with the main aim of reviewing environmental conditions in the Arctic Seas and assisting as a central facility for the collection, synthesis and interpretation of data on marine radioactivity in the Arctic Seas. The present report begins with an oceanographic description of the region and some observation fooe th dn schaio n pathways prevailing there. This informatio fundamentals ni o t understanding the transfer routes for any anthropogenic radionuclides released from the dumped objects. This them radionuclidf eo e transfe s continuei r repore Section di th f o t n4 which examines experimentaw ne a vi , l research conducte t IAEA-MELa d , whether low- temperature (Arctic) conditions chang parametere eth f marino s e radionuclide transfer into marine organism d sedimentan s s (relativ e commonlth o t e y published datr temperatfo a e latitudes). Finall repore yth t presents dat radionuclidn o a e concentration e Kard th an an i s Barents Seas and uses these data to estimate the inventories of radionuclides currently in the marine environmen Kare Barentd th f aan to s Seas. 2. DESCRIPTION OF THE REGION 2.1. OCEANOGRAPHY 2.1.1. Arctic Ocean The Arctic Ocean (Fig. 1) is nearly land-locked and is divided into two major basins: the Eurasia nCanadiae th Basi d nan n Basin, separate Lomonosoe th y db v Ridge. Bote hth Eurasian Basin, with maximum depths of around 4000 m, and the Canadian Basin, with maximum depths of about 5000 m, are further subdivided by lesser submarine ridges. Another important topographic featur continentae th s ei l shelf, underlyine aree th f th a o gf o abou % 30 t Arctic Ocean and comprising several shallow marginal seas (Fig. 2). The shelf bordering Eurasia extends out to 500-1700 km, while along the Alaskan and Greenland coastlines its width is under 200 km. The total area of the Arctic Ocean is 9.5-106 km2 and its volume is 1.7-10 km . The most important connection of the Arctic Ocean with the rest of the World 7 3 Ocean is through the 2600 m deep Fram Strait between Greenland and Svalbard. Shallower openings in the land belting the Arctic Ocean connect it to the Pacific and to the Atlantic through the Bering Strait and the Canadian Archipelago, respectively. Three main water masses can be defined in the Arctic Ocean: surface water, Atlantic water and bottom water [4]. The surface water layer originates in the marginal shelf seas and from local mixing of waters below the sea-ice cover following the freeze/melt cycle. It is the most variable of the water masses, its properties being influenced by the seasonality of ice formatio shelf/rived nan r wate dividee rb inputn ca d t I . int surface oth e polar mixed layer0 3 , deepm 0 to5 , containing fresh, cold (-1.4° -1.7°CCo t )underlyine waterth d an , g halocline, dow , wit m abouo nt h 0 increasin20 t g salinit temperatured yan ware 0°Co t d Th m.p an su salty Atlantic water layer extends below the pycnocline down to depths of 800-900 m and is characterized by a mid-depth temperature maximum ranging between 0.5°C and 4°C. This water mas generates si d fro Norte mth h Atlantic waters inflowing throug Frae hth m Straid an t ove Barente rth Kard shelvesa san aSe deee Th .p waters, extending belo Atlantie wth c layeo rt the ocean floor, have relatively high and uniform salinity (34.93 to 34.99%o) and temperature (-0.7 to -0.8°C in the Eurasian Basin and -0.3 to -0.4°C in the Canadian Basin). Besides the three main water masses described, in the Canadian Basin there is a thin interlayer of Pacific water, underlying the surface waters. The circulation in the Central Arctic is well understood (Fig. 3). The flow pattern in the Polar Mixed Layer is closely related to that of the overlying sea-ice. The prominent long term e featureBeauforth e ar s t e CanadiaGyrth n i e ne Transpola th Basi d an n r Drift Stream, directed from the Pole towards the Fram Strait. Circulation in the halocline is driven by anticyclonic flows on the shelves. The flow in the Atlantic layer is generally cyclonic. It appear occuo st boundarn ri y currents influences i , processey db shelvee th n so s (mainly those Barente o th f e steere d Karb an sy topographi y adb ma Seas d an ) c features.e Mosth f o t Atlantic water enter e Arctith s c Ocean throug e Frahth m e WesStraith n ti t Spitsbergen Current and leaves it in the East Greenland Current. A branch of the Norwegian Atlantic Current also brings Atlantic water into the Arctic Basin over the Barents and Northern Kara Sea shelves t depthA . e Centrath , l Arctic Basin e decouplear s d from extensive exchange. There, cyclonic flows appear to exist around the boundaries of the Canadian and Eurasian Basins. A summary of main inflows and outflows for the Arctic Ocean is given in Table I. a Se East S/bcrian Sea FIG. I. The Arctic Ocean. O rt •aoeh StiO M FIG. Bathymetry2. Arctic ofthe Ocean. East r S/beq ''Sea FIG. Main3. surface currents Arcticthe in Ocean (draftedfrom [3]). TABLE I. MAIN WATER FLOWS IN THE ARCTIC [5] From To Through Flow (Sverdrup)* Atlantic Ocean Arctic Ocean Fram Strait 4 Atlantic Ocean Barenta sSe Bear Island-North Cape 3.1 Arctic Ocean Atlantic Ocean Fram Strait 5 Arctic Ocean Atlantic Ocean Canadian Archipelago 2.1 Arctic Ocean Barents Sea Spitzbergen-Franz Josef Land 0.5 Pacific Ocean Arctic Ocean Bering Strait 0.8-0.9 Whita eSe Barenta sSe Gorlo Strait 0.015 Barenta sSe Atlantic Ocean Spitzbergen-Bear Island 1.2 Barenta sSe Arctic Ocean Franz Josef Land-Sv. Anna Trough 1.2 Barents Sea Kara aSe Franz Josef Land-Novaya Zemlya 0.15-0.54 Barents Sea Kara Sea Kara Gate 0.04-0.6 Kara Sea Arctic Ocean Wf Severnayo a Zemlya 0.6-0.7 Kara aSe Laptev Sea Sevemaya Zemlya-mainland 0.16-0.3 1 Sverdrup =10bmjs . The central Arctic is permanently covered by sea-ice, the exchange with the atmosphere being thus limite polynyao dt leadsd san . This, together wit share hth p pycnoclin about ea 0 t20 , almosm t completely isolate deee sth p ocean from non-particulate vertical exchange wite hth upper waters [5]. In the Polar Mixed Layer brine release leads to limited vertical mixing. The haloclin permanenta s ei , advective featur appeard nevee an b o st r penetrated waters It . e sar formed during winter freezin marginae th n o g l shelve advected san d int centrae oth l Arctic Basins, sinking underneath the Polar Mixed Layer due to their relatively high density. The salty Atlantic water t coosge l enoug reachinn hi Frae gth m Strai sino t k beneat Arctie hth c upper deee watersth pr waterArctie Fo . th f o cs Basin, vertical mixin restrictes gi neao dt r boundary convection, which may ventilate water masses down to the bottom of the ocean. Waters entering/exitin Arctie gth c Ocean throug Frae hth m Strai affectee ar t open-oceay db n convection which reaches bottodowe Greenlane th th o nt mn i dmid-deptho t Gyr d ean e th n si Iceland Sea. Residence time 2.5-3.f so 5 years have been derive fresr dfo h Barente wateth n d o r san Kara Sea shelves [5]. The mean residence time of freshwater in the upper layers of the Arctic Basin is 10 years, possibly 2-6 years shorter for surface waters than for the halocline. Conservative tracers transported fro shelvee muppeth e th o srt layerArctie th f so c Basin could therefore exit through the Fram Strait in about 5 years. Renewal times of tens of years, 50-100 years and 250—300 years have been estimated for the intermediate, deep and bottom waters of the Arctic Basin, respectively. 2.1.2. Barenta sSe The Barents Sea (Fig. 1), with an area of 1 424 000 km2 and a volume of 316 000 km3, lies mainly on the northern European continental shelf. It has a complicated bottom topography, which contributes to the complexity of distributions of water masses and sedimentation regimes mose th r t partFo . depths onlit d , an y variem 0 35 s betweed an 0 n10 sea'e dropth f s o oveareabeloo sm t % 0 1 r, w wit50 hmaximua attaine abouf m o 0 60 t da the boundary wit Norwegiae hth nvera Seas Barente y ha unstabl Th .a sSe e climate [6]e .Th atmospheric Arctic front forms at the boundary between the predominantly temperate air masses in the south and the cold Arctic air masses in the north. Considerable changes occur acrosmeae th Barenttemperaturr e n ai sth i a south-weste sSe th winten n i e (i C r0° , -10°Cn i the south-east and -24°C at Spitsbergen; in summer 9°C in the south and 0°C in the north), precipitatioe th n n (annuai m north-ease m 100o t lth 0 averag p n i u d m an tm e 0 value30 f so south-west) and dominant winds. Beside mais it s n connection Atlantie th centrao d t s can l Arctic Barente th , alsa Se so communicate White th d se witan SeaKar e a hth aSe t .receiveI s runoff from e riverth n o s mainland (Fig ) eithe4 . r directly, notabl Pechore yth a Rive 3 a"r (abou1 km )r throug ,o 0 13 t h the White Sea, mainly the Severnaya Dvina, Mezen and Onega (altogether 136 km3 a"1). There is a number of smaller rivers flowing into the Barents Sea from the Scandinavian and Kola coasts, amountin totae th lf riveo abouo gt % r 10 trunofBarent e th o t f s Sea. Rivers from Spitsbergen, Fran1 za" Jose3 Novaye km f th Lan3 3 d d an a an Zemly 7 aboud 3. , aad 36 t respectively. Snow/ice meltin mainlane islandse th th n go d dan also contribute frese th ho st water input [8]. Run-off significantly affects only the south-eastern part of the sea. Four main water masses can be identified in the Barents Sea [7]. The Atlantic water, warm (4—12°C) and saline (about 35%o), incoming from the west but also from the north, throug Arctie hth c basin locates i ,wester e th n di seane surface e parth .f Th o t , cold (<0-1°C), less saline (33-34%o) Arctic water, flow fron i snorthe mth relativele Th . y fresh (28-34.5%o) coastal water, with significant variatio seasonan i l temperatur salinitd ean y extends alone gth mainland and western Novaya Zemlya coasts. The Barents Sea waters, forming as a result of mixing betwee previousle nth y described water masse transformatiod san n unde effece rth f o t local conditions, reside mainl eastere th northerd n yi n an n sea e partth characteristi.f A so c featur polae th s rei front formin boundare th t ga y betwee cole nth d Arcti ward can m Atlantic waters, with temperatur salinitd ean y gradients reaching maxim f 1.3°ao C km" 0.2%d 1an o km"1, respectively t stronglI . y influences water circulatio affectd nan s chemica biologicad an l l condition vicinitys it n i s , leadin increaseo gt d content f biogenio s c element generaa d an s l abundanc lifef eo . The general water circulation in the Barents Sea is cyclonic. The strongest and most stable flow runs eastward along the northern coast of Norway. It is formed from waters of the Norwegian Atlantic Current and of the Norwegian Coastal Current [9] entering the Barents Sea sout Beaf ho r Islandcalles i Nortd e dan th , h Cape Current. Further eas t beari t name sth e of Murmansk Current, and at about 30°E is divided into a coastal branch and a northward flowing branch, part of which recirculates westwards. In the Barents Sea there are also a number of cold currents, flowing westwards and southwards. Important from the point of view of possible dispersion of contaminants from the Kara Sea is the Litke Current, coming into the Barent througa Se s northere hth Karne parth af o tGate s intensitIt . t welno ls y i known t bu , appears to be a factor of at least 7-10 times weaker than the current flowing eastward through the Kara Gate [10]. Main water inflows and outflows for the Barents Sea are summarized in Table I. FIG. Mean4. Annual Arctic runoffthe to Ocean (km3y'!) (drafted from [6]) 10 Tides decrease in amplitude towards the northeast, from extreme maxima attained at Norte th t hStraia Murmans n , Capi d m) t eWhitGorl6 e an ( th a lessef o okt o eSe ) fjordm r 4 ( s maxim Spitsberget aa , Franm) 1 zn( Josef Lan Novaydd (0.an ) 8m a Zemlya (0.8-1.. 4m) s stratifiei e wara th se mn e i d seasoTh t convectivnbu e mixing occur wintern i s i h , summer the halo-, thermo- and pycnoclines are situated at depths of 25-50 m. Due to the bottom topography, there are quasipermanent zones of downwelling and upwelling, like the Bjomoya Trough and the northeastern region [6]. A consequenca s e intensivth f o e e vertical mixing e Barentth , watera Se swele ar s l ventilated surface Th . e water oversaturatee sar d with oxyge summen ni eved wintean n rni r the oxygen saturation is not less than 70—80% [4]. Due to low temperatures, the deep layers of water are enriched in carbon dioxide. Due to the inflow of warm Atlantic waters, the Barents Sea is never completely ice- covered. A typical feature of the Barents Sea ice regime is the large seasonal and interannual variability largese Th .exten e ic t usualls i t y observe t variei Aprin d i d an sl from 55-60%f o the sea surface area in warm winters to over 70% in cold winters [6]. The smallest ice extent is recorded in August-September, when, in specially warm years, the sea is completely ice- free, whil anomalousln ei y col dcovee yearic e r sth persist s ove areara e 40-50se Th .e th %f o annual average, minimum and maximum ice cover extents are 38%, 22% and 52% respectively. Stable fast ice forms near the coasts. The ice thickness does not usually exceed margine seae th t th a . f Driftinso m 3 reache0. e gic s maximue mth n thicknessei m 8 0. f o s south-easternorthe th wintern n i I . m 5 , northwar1. n Barentd an a drife sdSe ic t prevails, while in summe southware rth d transport dominates. Extensive polynya formee sar d nea coaste rth s e o islandlocat oth f e le forme e du Barentswindsic th e a itseln i d Se Th s .usualli f y predominant, with some import from the Arctic Ocean and the Kara and White Seas. Ice import is considerably larger than export (Table II). However, the ice exchange of the Barents Sea is insignificant compared with the ice volume in the sea. The Barents Sea is characterized by a typical polar sedimentogenesis, with relatively low sedimentation rates and marked predominance of terrigenous sediments over bio- and chemo-genic ones [11]. A total of about 7.5 107 tonnes of terrigenous material is supplied to the Barents Sea every year, mainly by coastal and sea floor abrasion, but also by rivers and by deposition from the atmosphere. The White Sea receives an input of 9.3 10 1 a" . Suspended sedimen topee loadth nn i southerd sBarent rangan 1~ a g eSe snm frocoastaw mfe l areo at 7 1 ! several tens, even hundreds of mg I" in some of the fjords on the western coast of Novaya 1 Zemlya. Besides key factors like the complex topography of the sea floor and hydrodynamics, which control sedimentation regimes and mechanical characteristics of the bottom sediments, the presenc largf eo e permanently ice-free areas contribute activo st e resuspensio bottof no m sediments. This process mainly occurs durin storme gth y autumn-winter period, when wave action can affect sea floor sediments at depths up to 80 m and even deeper. Due to the existing system of permanent bottom currents, the resuspended sediment is entrained in long range transport .hav Sedimentatioa" e m beem n5 0. estimate o t Barente nt 1 a th rate r 0. a df fo sSe o 1 large [7]t value,bu orden a s f magnitudo r e expectee highe b wester e n th ca r dfo n Novaya Zemlya fjords. The whole spectrum of lithological types of bottom deposits is represented in the Barents Sea. South of 72°N sands are dominant, whereas to the north mud prevails. Generally a floo t se deptha s covere, i re f th leso s sm d tha0 mainl10 n sandy yb , often containing boulders, gravel and shells. Deeper basins are covered with mud. Clayey mud 11 occurs especially in the northern part of the sea. Due to the active hydrodynamic regime, bimodal grain-size distributions, as well as polycomponent sediments are dominant, monogranular sediments being very rare. Light minerals (quartz, feldspar e fine) th and -n i , grained sediments, also clay minerals (mainly illite) predominate [4]. Heavy minerals in the surface layer are in general between 1 and 5%, rarely more. The SiOa ranges from 85% in sands to 58% in muds and clayey muds, while metallic oxides vary from 8 to 25%, showing a clear correlation between the chemical and mechanical compositions. Manganese content increases from sande 0.01th f southern o si % n Barentabouo t a e northertSe sth 0.6 n i % n muds organie Th . c matter conten Barentn i t sedimenta Se s s ranges between 0.15-3.12r %fo carbon and 0.02-0.42% for nitrogen, both increasing in proportion with the clay content. The phosphorus content increases from below soute 0.05 th northe 0.32o hn th t %i n %i . Active chemical processes are related to precipitation of compounds leached by rivers from the mainland and occur principally in the fresh water-sea water mixing area. Densities between 1.35 and 1.99 g cm~3 and water contents of 30 to 67% have been generally observed for bottom sediments [11]. 2.1.3. Kara Sea The Kara Sea (Fig. 5) lies on the western part of the Arctic continental shelf of Asia and is connected with the Barents Sea to the west, the Arctic Basin to the north and the Laptev Sea to the east. It has an area of 883 000 km2 and a volume of 98 000 km3. The sea is rather shallow ares it ,a f continentahavin e o lyin th % n go g82 l shelf, with depthd an s, undem 0 r20 only reaching depths of more than 500 m over 2% of its area [6]. The most prominent topographical feature three ar s e submarine rifts Svyataye th : a Ann Voronid aan n Troughn si th Novayee nortth d han a Zemlya Troug south-weste th n hi , alon eastere gth n coas Novayf o t a Zemlya, with maximum depths of 620 m, 450 m and 430 m respectively. The Novaya Zemlya and Svyataya Anna Trough deem separatee 0 psar 10 northere sill a Th . y db n troughs form pronounced reentrants from the Arctic Basin into the shelf and play important roles — particularly the Svyataya Anna Trough — in shaping the water circulation between the Barents Sea, the Kara Sea and the central Arctic. Strong winter coolin wead gan k summer warming, unstable weathe cole th dn ri seaso n and relatively calm atmospheric conditions in summer are characteristic features of the Kara Sea climate [7]. Mean monthly air temperatures range between -20°C and -28°C in winter summern i C extreme 6° Th .o t r temperatureanC eai d1° s recorde -48°e d ar 20°C d Can n I . summer-fall winds are generally between 4-7 m s~], the frequency of winds less than 11 m s"1 winds bein f 88%o g . Extreme wind f e bora40-6o s th occu — ss~0m — ' r neae th r mountainous coast Novayf so a Zemly Severnayd aan a Zemlya, typically lasting several hours, but possibly lasting 2—3 days in winter. Storms are most frequent in the western Kara Sea. In winte stor7 r6- m day montsa recordede har . Precipitation amount 20-3o st a"m 10.c Ther five ear e main water masse distributioe Kar e [6]a th Th .aSe n si extend nan f o t these water masses has not only a seasonal variation, related to ice formation and melting, but also an interannual variability, which is controlled by atmospheric processes generated by the dominance of either the Icelandic depression or the Arctic pressure maximum. The surface water Arctie th f so c Basin com througn ei norte hth h fro centrae mth llocatee Arctiar d n dcan i the upper layers of the Kara Sea. They are characterized by rather small seasonal changes in salinit temperaturd yan e around typical value , respectivelysof , 32%o, slightly increasing with depth, and -1.8°C — that is, close to the freezing point. 12 F/G. 5. Bathymetry of the Kara Sea. The surface Kara Sea water can suffer modifications due to ice formation and mixing with other water masses therefors i t I . e characterize significany db t seasonal fluctuationf o s salinity and temperature: between 25%o and -1.4°C respectively in winter, and 22%o and 7°C in summer Barente Th . a waterSe s s originat Atlantie th n comd i e an c e inte Kara oth Se a betwee northere n th Novayf o p nti a Zemlya (Mys Zhelaniya Frand an ) z Josef Lan alsd doan through the Southern Novozemel'skiye straits, mainly between the southern tip of Novaya Zemly Vaygacd aan h Island (Kara Gate). This water mas characterizes si higy db h salinitl yal year round: 35.3%o in summer to 35.6%0 in winter. Its temperature is vertically homogeneous and varies from -1.9°C in winter to 6°C in summer. The salty and warm Atlantic water mass is formed from water flowing into the Kara Sea at depth from the Arctic Basin through the Svyataya Anna and Voronin Troughs. It presents no significant seasonal variation of salinity (35%o temperaturd an ) e (2.2°C). The river waters have a strong influence on the hydrological regime of the Kara Sea. Their temperature ranges between 0°C in winter and 11.7°C in summer. The extent of the water mass formed by river water discharge, usually defined by an upper limit of salinity of 25%o, may reach up to 30% of the area of the Kara Sea. A strong frontal zone develops where river runoff meets more saline shelf waters. Five main rivers flow into the Kara Sea from the mainland : Yenisey, Ob, Pyasina, Taz and Pur, the first two delivering more than 90% of a total estimated mean inflo 1 [8]f 110wo a" 150o 3 0.t Severa0km l small river intn e sru oth Kar froa amSe Novaya Zemlya, totallin ginfloe lesth f sw o tha fro% n3 m mainland riverss A . in the Barents Sea, there is a small contribution of fresh water inflow related to melting of alone snoic coastlines e d gth w an . The water circulation pattern in the Kara Sea is strongly influenced by river inflow. A cyclonic gyre forms in the southwestern Kara Sea, while in its northeastern part northward and eastward current givee ar Kare s a nth dominat f aSe o mai e t Th ] (Figou n . e [9 d flow 6) . an n si in Table I. It can be noticed that the dominant paths of water flowing out of the Kara Sea are northward, to the Arctic Basin, and eastward, to the Laptev Sea. Tides have average values ranging between 30 and 80 cm [6]. Maximum values of 1.8 m are observed in the northern part of the Ob estuary. Along the shores of Novaya Zemlya tidal amplitudes reach 0.5-0.. 9m During summer, due to melting of sea-ice, increased river discharge and insolation, well-defined thermo-, halo- and pycnoclines form at 6-8 m in shallow parts of the sea and at 20-30 m in deeper regions [12]. Cooling and ice formation accompanied by brine release result in strong vertical mixing during winter. Zones of upwelling and downwelling persist in the region of the continental slope and the troughs [7]. Oxygen concentration fairle ar s y high throughou e Kar a watersth t Se a . e Eveth n ni relatively enclosed Novaya Zemlya Trough, oxygen values are typically up to only 15% lower adjacene thath n no t shelf [12]. Ventilation occurconvectioo t e sdu n followin formatione gic , so that only nea bottoe th roxygee ar t mdepth a m n 0 exces n i svalue 30 f so s less tha% n70 saturation, indicating reduced renewal of waters. 14 FIG. Currents6. Kara (draftedthe Sea in from [9]). 15 Due to its severe climate, the Kara Sea freezes over in fall-winter and is never totally ice-fre formatioee ic [9] w , (FigNe n. start7) . Septemben si norte aboud th monthe n an ri on t h average e southe th late th n n ri O . , from Octobe Kare areMaye th o rt ath f ao f ,o abou% 94 t Sea is covered by ice. Mean thickness of fast ice is between 1.2 m in the southwest to 1.8 m in the northeast. Drifting ice in the central part of the Kara Sea can reach thicknesses of 1.5-2 m. The Novaya Zemlya ice massif generally melts in late summer but is a perennial feature in some years. In the northern regions ice persists all year round. Icebergs are observed in the southwestern Kara Sea, generally along the coast of Novaya Zemlya and appear to be calved mostly from glacier northere th n so n islan Novayf do a Zemlya notes i t .I d [12] that e mosth f to icebergs generate glaciery db Novayn so a Zemly trappee shalloae ar th n di w fjords. Thera s ei dominana t outflod froe ne an Kare ic m a f th w o taSe flux northward average Th . e transit time required for ice to drift from the Kara Sea through the Arctic Basin to Fram Strait is 2-2.5 a [12, 13], considerably fastetransia 8 r 5- ttha time nth e estimate r water dfo e tota e Th .ic l export to the Barents and Laptev Seas and to the Arctic Basin exceeds 400 km3 a"1 (Table II). The presence of the extensive ice-cover for at least 10 months a year, considerably damping wave action and river discharge are critical factors controlling the sedimentation regim Kare th an e i Sea tota.A f 1.4-1 o lterrigeneou~ a t 0 s materia supplies i l Kare th ao dt g -I Sea, 80% of which comes from coastal abrasion [6]. The main rivers discharge approximately 3-107 t a"1 of suspended matter, 80% of it being deposited in the estuaries. The Novaya Zemlya fjords are an important source of clayey material for the Kara Sea. However, only 1.5% of the particles discharged to the Kara Sea are dispersed beyond it [5]. The suspended matter content in southwestern Kara Sea waters is below 10 mg I"1, generally between 3 and 7 mg F1. Sedimentatio masket no Kars e i shelorgani a sloy s ndth i d b aSe n w fan o c oozes, since the metabolic productivity rates are also low. Sedimentation rates are estimated to be between a" m highee 1m , th 4 d r0. value1an s being attaine Novaye arean di th f so a Zemlya fjordsn I . the Kara Sea, bigranular silts (55%), sands (20%) and muds (20%) are dominant. In coastal areas and on rises, sandy and gravelly sands prevail whereas the deep sea bottom is dominated by clayey and silty sediments (Fig. 8). As typical for an Arctic continental shelf area with important river inflow, large numbers of ferromanganese nodules are found in some areas of the Kara Sea [4], along the coast and in the fjords of Novaya Zemlya (as observed during the Joint Russian-Norwegian 1994-1995 expeditions). Feldspar-quart d micaceous-quartan z z varietie f terrigeneouso s sediment dominane ar s twestere [4]th n .I n Kara Sea, densitief o s 1.4 1.6o 0t cm""5g wated wer3% an r60 e contentdetermineo t 2 3 f so r bottodfo m sediments organie [7]Th . c carbon rangcontene th 0.2f n eo i s 71.99o ti t % [4]. TABLE II. ICE TRANSPORT IN THE ARCTIC [5] From To km3 a~! Barenta sSe Arctic Ocean 32-33 Kara Sea Barents Sea (Kara Gate) 4.6 Kara Sea Barents Sea (Northern top of N. Zemlya) 140-198 Barents Sea Kara aSe 20 Kara Sea Laptev Sea 50 Kara Sea Arctic Ocean 170 Arctic Ocean Barenta sSe 43.5-58 Barents Sea Whita eSe 50 White Sea Barents Sea 13.6 Arctic Ocean . GreenlanE Greenlane th y b da CurrendSe Fraa tvi m Strait 2600 16 Polynyas Fast Ice Stable Ice Massifs characteristicsIce 7. FIG. Kara of(draftedthe Sea from[9]). 17 FIG. S.Kara Sea sediments (draftedfrom [3]). 18 2,1.4. Kara Sea dumpsites The only specific information available for the sites where radioactive waste has been dumped is derived from reports of the 1992-1994 joint Russian-Norwegian expeditions to the Kara Sea [14-16]. Abrosimov Fjord (Fig. 9) has smooth topography, with depth reaching maximum values of about 20 m inside the fjord [16]. There are two inflowing rivers, the main inflow occurring through Abrosimov River fjore clearls Th i .d y unde influence th r f Barento e a Se s waters flowing into the Kara Sea through the relatively nearby Kara Gate. High salinity (33.4%o to 34.1%o, except for a very thin desalinated surface layer) and temperature (0.4°C at the surface to over -1.2°C at the bottom) were recorded in August-September, and several water massee clearlb n yca s identifie profilesD d CT fro e .m th Botto m sediment generally consists of fine mud, with clayey mud covering the central part of the fjord. The bottom of the shallow mouthe area rivere th t th s a f covere s si so d with mout e fjore sandth th t df hA o .ther e are coarse sands covered with gravel. Life is relatively abundant in Abrosimov Fjord. Stepovoy Fjord has widths below 2 km on the 10 km stretch investigated in 1993 and 1994 (Fig. shallo10)A . w sil t aboudepta lm 0 h2 t separate innere sth , deeper part (maximum ) fro deptoutee m mdissolveth 0 A h 6 fjor. e r parth m) d f 0 o t(depth d4 oxygeo t p su n profile measured in the inner part of the fjord indicates good ventilation of bottom waters [16]. In September innee th , r basi relativels nwa y strongly stratifie compares da outee th ro dt parf o t the fjord and the nearby coastal area. In the inner basin, the water temperature went from 3.7°surface th t C a -1.7°o et C nea bottoe rth m while salinity ranged from aboue t th 20% n i o top 10m to 34.8%o at the bottom [15, 17]. Temperature and salinity were quite constant below outee th 35 fjorn e rI . par th df o ttemperatur e varied very little with depth, rangbeine th f n gei o 2.6-3.4°C. Salinities slowly increased from centra17%e 28%th o t on i ooutele partth f ro basin, moutwhile fjore th th t df ea ho the y were constan t 18%a t o dow 15-2o nt , the0m n gradually increase 24%o dt o nea bottome rth frese Th .h water componen thus i t s more importane th n i t oute fjord e rbottoe parth f Th .o t m sediment thin si s area also indicate strong flushine th f go bottom innee th rn I .basi n grave concretiond an l s lin bottoe eth e mth shoreclose o t th d o et s an sill. The deepest region is covered with fine silt. Tsivolka Fjord is a relatively open inlet (Fig. 11) with typical fjord-like topography. In September, the water temperature was 3.5°C at the surface and -1.5°C at the bottom, with a thermocline at around 20 m depth [15, 17]. Salinity ranged between 14%o at the surface and 38.4%e bottom e bottoth th t a on I m. layer water turbidit s highywa . Excep r shallofo t w nearshore sites and high bottom current areas at the mouth of the fjord, the bottom sedimentary material consists of fine mud. The fjord is rich in benthic fauna, particularly sea- stars (Ophiuroidea), isopod amphipodd an s s (Gammarida). mose Th t abundant specief o s seaweed are Fucus evanescens and Laminaria digitata [17]. Fish are rare. The fjords are completely frozen in for at least 10 months a year. Average flushing times of a few months can be expected on average, somewhat slower in winter due to the ice cover [18]. Complete flushing of the fjords, especially the smaller, shallower ones, can occur during coupla dayf eo s under storm events scourine signo ic . N f so g were see visuat na l inspectiof no fjore th d bottoms. 19 Reactor comp. 1,2 •:•::: •:•:•:•;•:•::::::: •:•:•:•;:: •:. •'•• !•/!•!•;•.•!•!•'.•!•/;••;•>"•!•>!•;•/!•/. ^>>><>>^i>>>>>?>>>;><<>% > N -::;:::::;:::::;:::;:::;::::::::::::;:::::;::;: ,.- ; ': : / : ; : .- / ; ; - ; ; /; : / ; : : .• . . .^. ^!- / '.•': .'': ': / 1-'.-': ': ': '; '; '; ': ': ': '.•': ':•': ': ': : F/G. 9. Bathymetry ofAbrosimov Fjord with localized dumped objects. N Fine sediments Bottom covered with gravel ...;m^m^ ^^^:,:;,,. FIG. 10. Bathymetry ofStepovoy Fjord with localized dumped objects. N A Region (according to Yablokov et al., 1993) of dumping of the LENIN reactors without fuel (not localised). Region (accordin Yablokogo t t al.ve , 1993 dumpinf )o g of spent fuel of the LENIN reactors (not localised). 0 1 Containers MILES FIG. 11. Bathymetry ofTsivolka Fjord with localized dumped objects. 22 Novaya Zemlya Trough (Fig reache) .12 s . Temperaturdepth aboum o t 0 p su 43 t d ean salinity profiles [15] have allowed identificatio f fouo n r main water masses whicn i , e hth influence of river water, of water of Atlantic origin and of processes related to ice formation can be recognised [17]. The surface layer has relatively low salinity (about 32%o) and high temperature (2-2.5°C). Belo share w th salinite pth , haloclinm y 0 smoothl2 t ea y increases with depth from about 34.5% almoso ot t 35.4%o temperaturee Th . , however constans i , - t a t 1.75°C dow , increase aboum o n t 0 maximua 10 t o st abouf mo , thet m -1.2°n0 slowl15 t Ca y decrease -1.86°o t s C (near-freezing temperature) nea bottome th r hige Th h. densite th f yo bottom water will obviously lead to increased residence time of water in the lower layers of the trough. At the investigated sites the bottom is covered with fine sediments and is inhabited b benthiya c fauna composed mainl brittlf yo e star amphipodsd san . 2.2. ECOLOGY 2.2.1. Biological production in the Arctic Biological productio hign ni h latitude ver d usualls si an y unevew ylo n throughoue th t year vere yTh . poor illumination over yeamuce th rf hwito h darkness ove extreme rth e winter months, reflectionloso t lighf greatlse e o th du t d yan , reduced penetratio thice th e kic o t e ndu cover, severely limit primary (phytoplankton) production markeA . d seasonal changn i e primary production may be evident, however, since over the very brief summer of long days, a bloom of phytoplankton, mainly diatoms, is possible. Seeding of diatoms is normally satisfactory at high latitudes because some species, especially those which have resting stages, survivn icesnoe e ca soos th th . A w s n eni a cover thine disappearic se producinth d san g melt ponds, sufficient light can penetrate for growth even at very low temperatures because some indigenous species photosynthesis t temperatureea s below 0°C, thouge b ht growtno y hma efficient. In the Arctic Ocean, light penetration through the snow-covered ice is so poor that production increases only in late June to a fairly low maximum in August. The productive cycle lasts only abou month3 t primard san y productio t exceptionallno s ni y high even over that period. [19] suggested that mid-summern i , , productio Arctin i c waters could reacC g h1 m~2 d"1 but, where ice cover was maintained, it could be as low as 0.03 g C m"2 d"'. During winter, production is undetectable. With the extremely brief summer, annual production must be poor although determinations of annual biological productivity are very few. An assessmen e annuath f productionw o lt ne rat e f fractioo th e r f o totao ,n l biological productivity which depend resupple th n o sf nutrient yo continentae th o t s l shelvese b n ca , made from chemical measurements. Regional averag productiow ne e n derived from total carbonates measure uppee th n da"2 ri 1haloclin m" [20] C seconestimateg s A . 5 ewa 4 e db o dt estimate for new production was derived from the apparent oxygen utilisation rates, which were determined from modelling profiles of chlorofluoromethanes, salinity, temperature, and oxyge watee th n nri column [21] value Th . e obtaine shelr dfo f production, subjec severao t t l qualifications, was between 8 and 21 g C m"2 a"1. These numbers can be compared to values for total productio Arctie th n ni c Ocea 1 [22]a a' 2 s nA .mf rangin C g g8 9 betwee d an 2 n1 genera latitudely rulean t a , , inshore waters mor e tenb o det productive than offshore waters. Occasionally, offshore water shon sca w high rate productiof so n comparabl inshoro et e areas, but these are due to temporary enrichment and are not sustained, and annual production is always greate n inshori r e areas. This also appliee Arctith o t cs Ocea d biologicaan n l production wil generalle lb y more importan marginae th n ti l sea scentrae thath n i l basin. 23 71.5 56 57 58 59 60 °E • Nuclear submarine reactor with spent fuel (not localised). ^ Barge shipd ssan with solid radioactive wastes. • Other radioactive wastes. FIG.Bathymetry12. ofNovaya Zemlya Trough dumpsite with localized objects. 24 e fatf pelagio Th e c biological productio s i grazinn y marinb g e animals and/or sedimentatio particlesf no . Grazin phytoplanktof go zooplanktoy nb basie th y cs ni stean n pi pelagic food web. Still, in polar regions, herbivorous activity by pelagic crustaceans (copepods, euphausiids) s importandoe a t appea e no sb o s passivt ra t s ea sinkinr fa s g(a controlling phytoplankton biomass and distribution is concerned). This seems especially true in shallower regions and marginal ice zones, where there are large amounts of new production which are apparently not used within the euphotic zone by herbivores. This material apparently sinks from the surface layer and supports a large and active benthic community [23]. Ther deepee ear r regions, however whicn i , h grazin relativels gi y more important. 2.2.2. Marine food-web Arctie th n si c Marine food-web polan i s r region shorte sar , wit hcarbo3 onlo t y2 n transfers between diatoms and apex predators. The apex predators include baleen and toothed whales, seals, walruses, bears and seabirds of several families. In the Arctic Basin, sea ice is greatly consolidated except at its periphery, and over much of its surface never melts. Negative effect thi f coverage o s sic termn ei productiof so energd nan y transfer throug food-webe hth s are the prevention of access of land/air predators to the water column and, as already mentioned e inhibitioth , f ligho n t penetration and photosynthetie , thusth f o , c processes necessary for pelagic food-webs [24]. Positive effects of ice include the plankton blooms associated with ice margins, the provision of substrate from which micro- and macronekton seek refuge against predators, and a rich epontic community (i.e. living below the marine ice) that provides important inputs to pelagic food-webs [25]. Another habitat feature that strongly affect e trophith s c e Arctie levelth th n s i i cs physiographic setting e ArctiTh . c basi s i characterizen y broadb d , relatively shallow continental majoritshelvee th surface d th f san ice-covereys o i e d year-round; this resulta n si relatively unproductive ocean. The Bering Sea provides a narrow connection to the Pacific Ocean, and the East Greenland and Labrador Seas connect the Arctic with the Atlantic Basin. These connections provide important inputs of productive waters to small portions of the Arctic Ocean. They also exer majoa t r influenc regionae th n eo l zoogeograph Arctie th f yco marine biota, i.e. there is marked longitudinal as well as latitudinal change in faunal composition e intensTh . e cold that overlie e regioth s n during winte e a resulth s f a ro t surrounding land importane masseth d san t spatia temporad an l l change temperaturn si d ean salinity of the surface waters (see physico-chemical description above) result in dramatic seasonal large-scale east-wes north-soutd tan h migration manf so y species. In sub-polar waters , invertebrated e fismanth an h f yo e importansth thae ar t t links between primary consumers and higher levels of the food web are also species of great commercial importance, e.g. capelin (Mallotus villosus), herring (Clupea harengus), sandlace (Ammodytes hexapterus), and squid (Illex) in the North Atlantic low Arctic zone; and walleye pollock (Theragra chalcogramma) and herring in the Bering Sea low Arctic [26]. Thus, a great dea s knowi l n abou e lifth et cycles, abundance distributiod an , f thesno e important species hign I . h Arctic waters, however importane th , t secondary consumer relativele sar y less well known. Mos f whao t knows i t n about Arcti (Boreogadusd cco saidd),speciey ke a n si Arctic food-webs s comha , e through studie f predatorso s , especially ringed seals (Phoca hispidd] and thick-billed murres (Una lomvid) [27]. 25 In the Arctic Ocean, two trophic webs have been identified, one associated with the shallow nearshor e otheth d r wit an epelagie th h c offshore habitats [26]. Arctie cth cod, pagophilic amphipod (Apherusa glacialis), euphausiids (Thysanoessa), d copepodan s (Calanus) are central to the pelagic web and are important in that of the nearshore, but in the latter, organisms of the epibenthos contribute substantially to energy flow. Arctic cod in their first year feed principally on copepods, but as juveniles and adults they switch more to amphipods suc Parathemistos ha [27]. Althoug numbeha mammalf ro componente sar e th f so Arctic marine food-webs year-round, especially polar bears (Ursus maritimus), ringed seals, and bearded seals (Erignathus barbatus), there are only two avian predators: black guillemot (Cepphus grylle) and ivory gull (Pagophila eburnea) [28]). Polynyas (areas within the ice pack almost always clear of ice and with enhanced productivity at their ice edges) are particularly importan developmene th o t thesf to e Arctic Ocean food-webs. Several apex predators winter in large numbers in the marginal annual ice of the Bering, Labrador, East Greenland and Barents Seas. Where large polynyas occur, these predators can be found within the pack ice as well. Included among the mammals are the bowhead (Balaena mysticetus), narwhal (Monodon monoceros), white whale (Delphinapterus leucas), ribbon seal (Histriophoca fasciatd), and walrus (Odobenus rosmarus) [28]. Major components of avian fauna are the ivory gull, as well as glaucous, Iceland, slaty-backed, and Ross's gulls (Larus glaucescens, L. leucopterus, L. schistisagus, and Rhodostethia rosed) and thick-billed murres (Una aalge and U. lomvid) [29]. At the Bering Sea ice edge, walleye pollock, capelin, euphausiids, and a pelagic amphipod (Parathemisto libelluld) are the mainstays of the midwater food web; walrus feed on molluscs of the benthos, and ribbon seals feed on demersal fish [30]. Copepod importane ar s t primary consumers t higA . h Arcti e edgesic c , Arctic cod, copepods (Calanus}, Parathemisto, and pagophilic amphipods are important in the intermediate trophic levels [31]. Farther south, Arctic cod, capelin . libellulaP e th d e an , ar major prey of upper-level predators. During summer numbea , migrantf ro s increas numbere eth predatorsf so t mosbu ,o d t so onl ice-fren yi e waters r exampleFo . , harp seals move nort epibenthoe feeo hth t n di e th n so shelves of the eastern Canadian Arctic as do Gray whales, fin whales and other baleen whales, as well as fur seals which frequent oceanic waters along continental slopes. Also moving into polar water mane sar y specie seabirdsf so mose ,th t abundan whicf o t oldsquae har eided wan r ducknearshore th n si e (where the yepibenthos)e feeth n di shearwatersd an , , northern fulmars, kittiwakes, murres, auklets and dovekies. Arctic cod is paramount to the food web of high Arctic areas, but key prey vary regionall Arctiw lo cn yi areas exampler .Fo easter e th n ,i n Barent durina sSe g summer, Arctic maie th ns i pre d wester e seabirdsf yco o th n i nt Barentbu , s Sea, whic strongls hi y influenced ware byth m North Atlantic Curren t thaa t t time, sandlace, capelin herrind an , importane gar t food item predatoro st s [31]. The central zone of the Kara Sea is low in productivity, with few and small-sized fish. Echinoderms dominate as predators; therefore, the energy transfer to the higher trophic levels through the food-web there is small. The trophic chain to higher organisms and humans in the more coastal environmen shows i whic 3 f thia 1 o t Fign sse ni .h highlight majoe sth r energy shalloe flowth n si wpotentiae th water seae , th f lso seafood source humanr pathe sfo th d s san through which radionuclides or other contaminants in the environment may reach humans. 26 gulls guillemot ringed seal harp seal Benthos, epibenthos -toJ FIG. 13. Food-web of the upper trophic levels in the shallow Kara Sea and potential food sources for man. 2.2.3. Fish and fisheries in the Barents and Kara Seas The estimated average annual primary production of the Barents Sea of 110 g C mf2 a"1 is far more than the average for the central warm ocean (<50 g C m~2 a"1) and the ice-free parts of the Antarctic ocean (<20 g C mf a"" ), but is a little less than that estimated for the Bering 2 1 continentae th n o Sed aan l shel Norwaf fof y [33]. This primary productio animale basie th r th fo s nsi grazin , i.esecondarit e .th n go y production or better, the zooplankton production. The main zooplankton populations consist of the copepods (mainly Calanus fmmarchicusm, C. hyperboreus and C. glacialis) and krill (mainl smallee yth r species Thysanoessa inermis, . raschii. longicaudatd).T T d an Amphipods have als importann oa Arctie t rolth n ei c ecosystem f thesO . e Parathemisto libelluae th s i most abundan importantd an t predatoa s A . smallen o r r zooplankton t formi , importann a s t link to the next step in the food web, i.e. seals, polar cod and diving birds [36]. The Barents Sea ecosystem contains some of the largest fish stocks of the world, i.e. the capelin (Mallotus villosus) whicmaximua d hha m registered seventiestocd mi ke sizth f so n e i abou millio5 7. t n tonnes [34]Northease th , t Arcti (Gadusd cco morhua) wit hstoca k sizf eo abou millio6 t n tonnes just afte secone th r d Worl partlr [35d Norwegiaan e ]dWa y th n spring spawning herring (Clupea harengus) whicmaximua d hha m stoc kmillio0 1 siz f eo n tonnes befor t collapseei 197n di 0 [37]. The annual harvest is from 2-3.5 million tonnes and the catches for the most, divided between Norway and Russia. There are strong interactions between these stocks, and variations in the year-class strength of the various fish stocks have a marked influence on other components of the ecosystem [34]. In addition to the direct harvest of the area, the Barents Sea is important as a feeding ground for fish populations harvested further south on the Norwegian shelf. The Norwegian shelf from 62°N and northwards is a spawning ground for the most important fish populations of the northeast Atlantic. Fish-egg and fish-larvae are transported via the Norwegian Coastal Current int Barente oth s Sea, wher havy benefie ma e th fis y abundanf hfr o t t food. Kare ichyofauna Th aSe poorer fa e raar tha rice nth h selectio commerciaf no e l th fis f ho Barents Sea. Fis kepe har tsever e awath y yeb climatic conditions Kare founth an di Seae Th . Atlantic boreal and arcto-boreal species have a limited occupational area in the Kara Sea and are found mainle southwesterth n i y n sectors . 4 familie2 Ther e f ar efiso s h wit3 5 h representatives in the Kara Sea. Polar cod (Boreogadus saidd) is the most abundant and widespread species in the Kara Sea whereas navaga (Eleginius navagd) and polar plaice are usually coastafoune th brackisd n di lan h waters. e fishTh populatio s verni y small withi e centranth l area whic s characterizei h y db brow justifiably n ma mud d e callean sb y d "the fishless zone". Thi s explainei s e th y db generally lower productive properties of this body of water and by the brown mud possessing conditions unfavourabl fish-lifeo et bottoe Th . m fish communit deee th pf y o water s consists primarily of small-sized members of the Cyclopteridae, Zoarcidae and Cottidae families (Artediellus, Ulcina, Licodes, Liparis Triglops).d an However, even these small-sized fise har extremely rareonle Th y. Barent speciea sSe s alslone th og s browi e founroug th d n di hnmu dab (Hippoglossoides platessoides) that live smaln i s l number s immatura s e specimenr o s mature dwarfs. The smale yar sizn grod i l ean w s slowlyi b exampler da yea 7 Fo .d o t rol 6 a , 28 17.o t Kar 15.e e lonwhilspeciea 5e 5m th th c th an Se g n i thit i e a sag sm c measure 1 3 o t 0 s3 Barents Sea. Closshoree th situatioe o et th , differens n i morr fa fisd e har an abundantt mouthe Th . s of the great rivers Ob, Yenisey and Pyasina abound in fish. Suitable conditions for local brackish water fisheries southere existh n i tmainlan e nSeae th parf th f alonof ,d o t dan e gth coast of Novaya Zemlya; industrial fisheries have been developed in the relatively productive Ob-Yenisey sector [35]. The northern char (Salmo alpinus) is found in the mouth of the rivers of Novaya Zemlya. Other majo e Arctir th a whitefishefise cSe ar h s (Coregonus), frostfish (Osmenis), navaga, Arctic cods goby(Gadidae)d Polaan e .b th Mand rda an y other fish caught there belon coregonide th o gt salmonided san s (beardie, Stenodus leucicthus nelma, grayling and others). Polar cod (Borogdadus saidd) is fairly frequently caught off the Novaya Zemlya coast, especially within the regions of the Kara Strait and Matochkin Strait. There is no commercial catch of fish in the open area of the Kara Sea. Closer to the coast f commercia,o navage ar polad d aan e amon co r us l fisa gse h Ob-Yenisee andth n i , y sector, migrator d semi-migratoran y y f speciecommerciao e ar s l importance (frostfish, whitefish, nelma (Stenodus) and golets (Salverius)}. The fishing of the latter group usually takes place during spawning in the mouth of the rivers. Separate statistics on fisheries for the t exist thein no i o s include.i d rO ThiKar a vasa FA Se saSe ty db fisherie s are, i.ee 18 aTh . Arctic Sea' whereas by ICES is included in the Barents Sea zone (ICES area 1). National fishery dat alargese existh r tfo tSea e gulfth 1990f n :i so totae estuarb th , O l s catce yth wa n hi 1526 tonnes of sea and brackish water fish and 836 tonnes of freshwater fish whereas the total fish catch was 228 tonnes in the Yenisey basin [7]. Whitefish were the most abundant species catchee inth bott sa h places. 3. RADIOACTIVITY OF THE KARA SEA 3.1. MARINE RADIOACTIVITY DATABASE The LAEA-MEL, withi IASAe nth P programme bees ,ha n actin centraa s ga l facilitr yfo the collection, synthesis and interpretation of data on marine radioactivity in the Arctic Seas. The data have been include e IAEA-MEth n i d L Global Marine Radioactivity Database (GLOMARD) which has been developed to store all data on marine radioactivity in seawater, sediments and biota [39]. The database is designed to serve the following functions (i) to provide immediate and up-to-date information on radionuclide levels in the seas and oceans, (ii) to provide a snap-shot of activities at any time in any location, (iii) to investigate changes in radionuclide levels with tim (ivd eidentifan )o t y gap availabln si e information. The data format has been rigorously prescribed to meet programme objectives and ensure maximum informatioutilitye th f o n containe databasee th n di degree Th . f detaieo s i l extensive (general sample information including type, method of collection and location as well as physical and chemical treatment) to allow the data to be validated and its quality assured additionn I . database th , links e ha lAEA-MEL' o st s in-house analytical quality control database allowing immediate checks on laboratory practice. Information is stored in such a way as to facilitate data interrogation and analysis. 29 The database provides critical input to the evaluation of the environmental radionuclide assessmene th regiolevelo e t radiatioe th d th f sf no an o t n dose localo st , regiona globad an l l human populations and to marine biota. The database enables : (a) Evaluatio f nuclidno e ratio allows— identificatioe sth individuae th f no l radionuclide contribution radioactivito st regione th n yi , whic criticas hi l give multiple nth e naturf eo the source terms. (b) Investigation of time trends — given the temporally varying nature of the known source f radionuclideo s e regionth e databasn i th s, e help o estimatt s e source contributions to the environmental concentrations and thus increases the sensitivity with whic smaly han l residual chang detectede b trenr eo y dma . (c) Inventory calculations — the ability to carry out budget calculation may again permit the detection of any imbalances. (d) Model validatio provido t n— e reliable prediction impace th f reasf o o thypotheticar o l l discharges, it is necessary to use validated models and this requires access to the existing appropriate experimental data (eithefore th f timm o n ri e serie observatiof so n or a snap-shot of activities). About 50 MB of data (6000 inputs) from the Arctic Seas have already been entered, with initial emphasi e extensivth n o s e joint Norwegian-Russian data, LAEA-MEL'n ow s measurement datd san a obtained from other institutions. 3.2. PRE-1992 RADIONUCLIDE CONCENTRATIONS Result radionuclidf so e measurement watern si , sedimen Arcti e biotd th an tf aco Ocean are sparse as can be seen from Fig. 14, where sampling stations of 11*7Cs is surface water are shown thadensite w lo Th t. o sophisticatef dats yo s ai d method f dato s a analysis cannoe b t used for data evaluation. The evaluation of time trends may be carried out only for the Norwegian, Barents and Kara Seas. 3.2.1. Water Fig. 15 (a) shows the evolution of yearly averaged surface concentrations of 90Sr and I37Cs with time in Barents Sea surface water. The only well-documented record available is for Sr [40] and partially also for Cs [41, 42]. Sr levels are gradually decreasing from an 90 137 90 e presenn 196i th 3 o 4t m" taverag q valuB f abou9 m~q eo 1 e B 34 sligh.tA t increasn i e concentrations at the end of the seventies and the beginning of the eighties may be associated with Sellafield peak releases in the mid-seventies. This is, however, much better documented by 137Cs records, although ther e alsar eo values missin r severagfo f theso l e yearsn A . approximate transit time from Sellafield to the Barents Sea can be estimated to be 4-5 years. The data from GLOMARD show that there has been a decrease in the anthropogenic radioactivit recenn i Kare a th f atSe yo year s (Fig (b)) 5 exampler 1 . Fo . 137e th ,C s contenf o t surface Kara Sea water decreased from (18-27) Bq m~3 in 1982 in the south-west Kara Sea t presenta 3 [40(3-8o t nf ] .q Thi)B s trenreflecy dma considerabla t e decreas weaponn ei s testing fallout and probably also the reduction in 13 Cs discharges from the Sellafield reprocessing plant. Sr in surface waters shows similar trends, the levels having decreased 90 from (7-21) Bq m"3 in 1982 [40] to present values of (3-11) Bq m~3. 30 FIG. 14. Sampling stations in the Arctic Seas for Cs-137 surface water (1965-1995). I IIIIII Sr-90 I 1I Co) AverageFIG.15. concentrations of Sr-90 Cs-137and surfacein bottomand waterthe in Barents Kara Seas.and (b) (a) 32 In the histogram shown in Fig. 15 (b) for the Kara Sea, high 90Sr concentrations (about observee b sixtiee n th ca n d m~i q s3associate e 3) 9B b whic y hma d with local fallout [43]; medium concentrations (below 15 Bqnf3) in 1970, 1971 and 1982, and low concentrations (abou m~q ) B 5 t have been observe recenn di t yearse CTh . s dat onle aar y available from 3 137 1982, and the value for that year (about 20 Bq m~) is consistent with mean Sr values. 3 90 Present concentration muce sar h smalle therefor d speculatn r an (abouca m~q e 3) B eon t6 e that the 1982 value may represent the peak Sellafield signal in the Kara Sea. The approximate transit time from Sellafiel Kar e woula th aSe o d t d7 years the 6- pre-199 o e nN .b 2 date aar availabl 239+240r efo pu concentration Kar n waterssi a aSe . The spatial distribution of » *)rj Cs in the Barents and Kara Sea surface and bottom waters for time intervals in the period 1965-1995 is shown in Figs. 16 and 17, respectively. The effect of transport of Sellafield I37Cs to the Barents Sea, especially for the years 1981-1985 anrecene dth t decreas 137n ei Cs concentration clearle b n ysca seen. Because of the above temporal trends coupled with residence time, deeper waters 137 239+240 (>50m opee th nn i )Kar shoa aSe w higher concentrationf so d Csan pu than surface waters, by about a factor of 2-3. The spatial distribution of 90Sr in Barents and Kara Sea surface waters depicted in Fig. 18 also shows a considerable decrease of 90Sr levels in the open Kara Sea. Remarkably higher Sr concentrations have been observed in the central and eastern Kara Sea, which may be due 90 to discharge radioactivf so e wastes fro formee mth r Soviet Union's nucleab rO plante th o st river but also due to runoff of global fallout from the catchment areas of the Siberian rivers and discharges from reprocessing plants in Western Europe. Pu-date Barente Th th r Kard afo san a Seas' water vere sar y sparse. Howevere b n ca t i , 238 239+240 seen fro -otha9 e mm1 th t p Figu./ 19 pthau ratt thioe fn pu/Barent watea abovs Se s wa r peu 0.1ra, t which 238 239+240 would indicate its transport from the Irish Sea 3.2.2. Sediment Pre-1992 radionuclide dat r sediment vere afo ar Kare ya th sparse aSe n si highes e Th . t 137Cs level wer) dw se (arounkg"observeq 1 B seventiee 0 th d centra20 e n di th easterd n si an l n Kar (Figa . aSe 20). Data fro eightiee mth surfacn i ss sho weighC y ewdr r (4-20tfo g k q )B sediment [40] comparee whicb n hca d wit presene hth t values (18-32[44-A7].w d kg"q 1 )B There are no pre-1992 data available for 2 +24 Pu concentrations in Kara Sea sediments. 3.3. PRESENT RADIONUCLIDE CONCENTRATIONS IN THE KARA SEA 3.3.1. Dumpsites Radionuclide analyses of water, sediment and biota sampled at the major dumpsites in Tsivolka, Stepovoy and Abrosimov Fjords and the Novaya Zemlya Trough show that radionuclide concentrations are generally low, similar to those observed in the open Kara Sea. However, very localized contamination of sediment has been observed from leakage of waste containers in Abrosimov and Stepovoy Fjords (Table III). Text cont. on p. 40. 33 1981 1985 80- 70- £ e 0 10 0 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 10 5 1C IS 20 25 SO 40 SO 100 150 Bq/m3 FIG. Cs-13716. Barentsin Karaand Seas surface waters. 34 9N 70- 80- 30- 70- E e 0 10 0 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 10 1 5 10 IS 20 25 30 40 50 SO 70 Bq/m3 FIG. 17. Cs-137 in Barents and Kara Seas bottom waters. 35 80-1 80H 8C" 70- 80- 70- 50 60 70 80 90 100 SE 10 20 30 40 60 80 100 Bq/m3 Sr-90FIG.18. Barents in Karaand Seas surface waters. 36 Pu-238 0 10 0 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 10 Pu-239+240 70 10 20 30 40 50 SO 70 1E-004 1E-OOS 1E-002 IE-001 tt+QOO 8q/m3 Pu-238/Pu-239+240 10 20 30 40 50 80 70 80 90 100 SE 0.01 0.05 0.10 0.50 1.00 FIG. 19. Pu in Barents and Kara Sea waters (1980-1995). 37 80- 70- 70- 70 30 40 50 70 80 90 100 2 4020O 0 SO100 k 10050 k30 Ba/m3 FIG. Cs-13720. Barentsin Karaand Seas surface sediments. 38 TABLE III. RANG CONCENTRATIONF EO RADIONUCLIDEF SO KARN SI WATER A ASE SURFACD SAN E SEDIMENTS (1992-1994] ) 54 [17 , ,44 137 90 239+2 40 p 60 Cs Sr u Co Water Sediment Water Sediment Water Sediment Sediment (Bq nT3) (Bq kg"'dw) (Bq nr3) (Bq kg 'dw) (mBq irf3) (Bq kg"'dw) kg-'dwq (B ) Site Surface Bottom Surface Bottom Surface Bottom Abrosimov 4_7 4-9 9-8400 2-4 2-4 0.3-350 5 3- 0 1-1 7 3- 8 Stepovoy Fjord 3-9 6-32 7-103000 2-7 3-26 0.4-300 5 2- 2-18 0.1-15 0.1-3100 Tsivolka Fjord 4-6 6-14 4-30 4-6 3-4 0.4-14-10 5-8 0.03-0.5 NTrougZ h 4-7 7-14 7-308 3 0. 2- 2-4 4 3- 7-121 <2 Open Kara aSe 8 3- 8-20 2-33 6 4- 3-10.3-0.1 8 8 2- 5-16 0.4-1.3 3.3.1.1. Abrosimov Fjord An example of a profile of 60Co, 90Sr, I37Cs and Pu isotopes in sediment collected in 1994 at the container dumpsite in Abrosimov Fjord is shown in Fig. 21. The concentrations of all detected radionuclides were higher by a factor of 10 to 1000 than those at uncontaminated sites. Contamination by fission products (137Cs up to 30 kBq kg"1 and 90Sr up to a few kBq kg" 1 dw), activation products (60Co up to a few hundreds of Bq kg""1 dw) and actinides (239+240Pu up to 18 Bq kg"1 dw) have been observed in sediment profiles [48-54]. The 238Pu/239+240Pu activity ratio strona , g indicato plutoniuf o r m marinorigie th n ni e environment, ranges from whic7 0. 0. o 3ht differs significantly fro value m th r globa efo l fallout (0.03 suggestd an ) sa waste origi r plutoniufo n e sedimenth n mi t coree samplinTh . g site wher e highesth e t contamination is observed does not contain reactor compartments, only low-level wastes packed in containers. This observation implies that leakage probably occurred from dumped containers due to their poor quality. However, the leakage has not led to a measurable increase of radioactivity in the outer part of the Fjord. The highly localized character of the contamination suggests that leakage probably occurred in particulate form. Some radioactive particles have also been identifie sedimene th n di t samples [51]. Fig. 22 shows a map of Abrosimov Fjord with localized dumped objects and contours of elevated Cs concentrations in surface sediments calculated on the basis of data reported in 137 [52-54] similaA . r distributio bees nha n observer Codfo , d San r Pu. However, H , 90 I37 239+240 60 239+24090 3 Sr, d Csan pu levels observe fjor e watee withie th th ar d f typica n e dro i n th l range opee foth r n Kara Sea. This would imply that leakag t continuinno s ei present ga thad e an tth sediment contamination observed occurre paste th .n di Radionuclide inventorie t locationa 2 sedimentn i sm" 300o t q s p 0 kB u r !37 fo e sC ar s 60 239+240 where leakages have been observed. Similarly Co and pu inventories are up to about 3 m~q 2, kB anrespectivel2 d0. y [53]. 3.3.1.2. Stepovoy Fjord Perhaps the single most persuasive piece of confirmatory evidence of background radionuclide levelFjore th lAEA-MEL's dn i si s sea-bed gamma-spectrum fro sedimene mth t surfac Stepovoe th t ea y Fjord dumpsite (Fig. 23). This spectrum obtained using lAEA-MEL's underwater survey system which include propane-coolesa d HPGe detector [18 e ,55]0 ,5 on s i , of the first sets of high resolution gamma-spectra ever recorded in situ in the marine environment spectrue Th . m show glanca t sa predominance eth gamme th f lineey o ara s from naturally occurring (background) radionuclides, namely from 40K and the U and Th decay series onle Th y. identifiable anthropogenic radionuclid 137s ei concentratioa Ct sa n whics hi clearly well below thos f naturao e l radionuclides, indicating that, even nea thio t r s major nuclear waste dumpsite e gammth , fluy s ra essentiallai x y natura composition i l n i d an n intensity [18]. Higher concentration 137f so Cs, 60Co isotopekg"u q P , 90kB d 1 S,0 an r s11 (137o t Cp su 1239+2401 1 9060 kg"q B kg"q 0 )d 1 kB havkg"q an o 3 t kB e0. p ,3 beeu o t o t Sp n Cru p ou measured only at very localized places around dumped containers [14, 59, 50] (Fig. 24). As in Abrosimo a measurabl o t vd le Fjord et e leakagno th increas, s ha en radionuclidi e e contamination the outer part of the Fjord. Text45. cont.p. on 40 DEPTH (cm) oo ro 11 " *"*• 3 o' "• 8 a. 00 0> ro °N to 71,95 71,93 711 71,91- 30 40 60 100 5000 6000 7000 Bq/kg dw FIG. 22. Cs-137 in Abrosimov Fjord surface sediments. 600- 500- 400H i 300 o O K-40 Pb-214 + Pb-212 200 Pb-214 ANNRAD TI-208 Bi-214 100H Cs-137 0- 500 1000 1500 Energy (keV) FIG. 23. In-situ sea-bed gamma-spectrum measured by an underwater HPGe spectrometer in LO Stepovoy Fjord 1993.in Spectrum accumulation time9500s.was 10 30 100 200 300 Bk/kgdw FIG. 24. Cs-137 in Stepovoy Fjord surface sediments. Measured concentrations of Sr, Cs and pu in the inner part of the fjord bottom 90 137 239+240 5 highea facto3- y f b wateo rr e a surfactha ar rn i n e water, indicatin a gleakag e from containers outee th fjorde n rconcentrationI .e th par th f , o t typicae sar opee f thoso lth nn ei Kara Sea. Radionuclide inventorie sedimentn i s vary r 137ma syfo C sn i fro2 mm~ q belokB w1 uncontaminated locations to 110 kBq m~2 indicating that leakage has occurred. Similarly 60Co 239 240 2 and " pu inventories are up to 26 and 0.2 kBq m~ , respectively [53]. 3.3.1.3. Tsivolka Fjord 137 239+240 Sediment cores analysed from Tsivolka Fjord have shown Cs and pu concentrations comparable with those in open Kara Sea sediment [17, 52, 53] (Fig. 25). However, the presence of traces of Co suggest a local source of contamination. The observed 60 radionuclide profiles indicate a fast deposition of sedimentary material and effective mixing by physical and/or biological processes. spene Th t nuclea icebreaker'e r th fue f o l s t beereactono ns localizeha r y dan yetd ,an possible leakage associated with thi t beesno wastns ha reportede . Radionuclide concentration waten si typica e opee ar rth nf o lKar a Sea. Radionuclide inventorie sedimenn si t m"q rang 60 r 137d kB r 2C ,fo eoC3 fo an so t fro 3 m0. for 239+240 0.0 d nTq abouo an t 2 Pu,kB 3 p respectivelu ,0. t y [53]. 3.3.1.4. Novaya Zemlya Trough No local contamination of sediment has been observed [46, 47, 59], (Fig. 26). However, the nuclear reactor dumped in the Novaya Zemlya Trough has not yet been properly localized. mentiones A d previously concentration 137f 239o sd C ""san 240 expectee puar highee b o dt r in deep waters. While the Cs concentration in surface water varies between 4 and 7 Bq mf , !37 3 bottom water 137Cs concentrations are 7-14 Bq m"3. 137 239+240d Csan pu inventorie rang e sedimenn th i s aboun o ei t 0.3-0.e p u tar t 0.0d 8an 2 kBq irf2, respectively [53]. 3.3.2 opee .nTh Kara aSe The concentrations of anthropogenic radionuclides in Kara Sea water sediment and biot generalle aar y very low. 137Cs data show almost constant spatial distribution, however, Sr data, especially Sr/ Cs activit ywatea ratise n roi vary acros Kare sth a Sea ratie .Th o 90 90 137 anticorrelates with salinit indicated yan importance sth e Sth r f inpueo riveb t O fro re mth 90 (Fig. 27). The 137Cs inventory in the water column ranges from 1 to 4 kBq m""2 and shows a relatively smooth and linear correlation with water depth. This implies that there are no point source radioactivitf so y nea sampline rth g stations [47]. 45 The sediment column inventories, ranging from 0.5 to 0.9 kBq m , show an inverse correlation with water depth, suggesting an enhanced rate of nuclide scavengin 2 g in the higher particle fluxes associated with shallower waters [47]. The total 137Cs inventories in the open Kara Sea range from 1.5 to 4.5 kBq rrf2 [53]. In comparison wit amounte hth radioactivf so e fallout deposite northere th dn i n hemisphere [56], we estimate thae contributioth t f globano l fallou137e th C so t tinventor e Kara th Se an y i should be about 0.5 kBq nf2. This value is lower than the average measured value weighted ove meae rth n water Kare dept(1. a th m~q aSe n 5h i kB 2), suggesting thadifference th t y ma e reflect contributions from local fallout and from discharges from the Sellafield reprocessing plant. Indeed Pechore th n i , a Sea observee th , d I37Cs concentration muce sar h higher [46, ,57 58] which reflect its close proximity to the Cuba Chernaya underwater nuclear test site. 210 bees Pbha n assaye orden di estimato rt e sediment mixin accumulatiod gan n rated san to reconstruct radionuclide e paslevelth t n i s[46] e datTh a. confirm that mixing playa s dominant rol controllinn ei radionuclide gth e concentration surfacn si e sediment Kare th af so Sea. The estimated sedimentation rate is from 1 to 4 mm a"1. The 137Cs depth distribution is affecte sedimeny db t mixing (bioturbation post-depositionad )an l migratio caesiumf no e th s a , penetratio f 137o n Cn sedimeni s s deepei t r than woul e expecteb d d froe 210e mth P ag b determination. 239+240 2 The pu inventor sedimentn yi s betweei s n[53] 0.0e m" 0.0d Th 1q .an 3kB 238 239+240 239+240pu/i37Cs inventory ratios are about 0.03. pu/ pu ratios jn sediments are between 0.02 and 0.05 suggesting a global fallout origin for the plutonium in sediment (Fig. 28). Yenised 3.3.3an b y.O estuaries The Ob and Yenisey rivers are important suppliers of fresh water to the Kara Sea and possibl contaminantf yo s (e.g. 90137d SCsran ) from land based sources date aTh . clearly show 137 239+240 Cs and pu depletion from water at low salinity [59]. Therefore, fast sedimentation and scavenging occu t location a rsalinit w lo f o ys resultin n relativeli g y high sediment inventorie 137f so C s (1- m"q 52kB ) [53]. 3.3.4. Biota datThero n ae availablear pre-199n eo 2 radionuclide concentration Kar e biotn si th af ao Sea. From post-199 conclud2n dataca e w , e that typical benthiconcentratione th n i cs C f so 1 "37 1 137 239+240 fauna of the Kara Sea are around 1 Bq kg" dw. Cs and pu concentrations in gammarids were foun dd 0.0arounan q kg"15 B , 1. respectivelyd1 dw . Brittle stars 239+240 1 137 (Ophiurded) showed pu concentrations kg"aroun q . HigheB dw 1 d0. r valuef so Cs were observed for Polychaeta (Spiochaetopterus) between 6—17 Bq kg"1 in the tubes. For fish (Polar cod) caught in the open Kara Sea and in Abrosimov Fjord, 137Cs concentrations were about 1 Bq kg"1 dw. Algae samples showed 137Cs levels below 3 Bq kg"1 dw [52, 60, 61]. 137 90 239+240 Generally, the concentrations of Cs, Sr and pu jn biota samples from the Kara Sea are very low (the latter two radionuclides often below detection limits of 0.5 Bq kg" and 1 0.01 Bq kg"1 dw, respectively). Textcont.51. p. on 46 Region (accordin Yablokogo t al.t ve , 1993 dumpinf o ) g of the LENIN reactors without fuel (not localised). 74.4 ion (according to Yablokov et al., 1993) 01 dumping | of spen LENIe t th fue f o lN reactors (not localised). Containers 74.; 74.2 58.6 58.7 58.8 58.9 59.0 59.1 59.2 °E 10 15 5 Bq/kgd2 20w FIG. Cs-13725. Tsivolkain Fjord surface sediments. 47 °N 73.5 73.0 72.0 56 57 59 60 °E 15 20 25 Bq/kg dw Nuclear submarine reactor with spent fuel (not localised). Barge shipd san s with solid radioactive wastes. Other radioactive wastes. FIG. Cs-13726. Novayain Zemlya Trough sediments. 48 80- 80- 70- 80- 1985 1990 10 20 30 40 50 60 70 80 90 100 9E 0 3. 5 2. 0 2. S 1. 0 1. O.S Sr-90/Cs-13727. FIG. Barentsin Karaand Seas surface waters. 49 Pu-238 70- 50 60 65 70 75 80 85 Pu-239+240 ••004 IE-003 IE-002 IE-00" 1E+000 Bq/kg Pu-238/Pu-239+240 0.01 0.02 0.03 0.04 O.OS FIG. 28. Pu in Kara Sea sediments (1992-1995). 50 3.3.5. Intercomparison exercises Intercomparison exercises were organise y IAEA-MEb d e laboratorieth r fo L s performing analyse samplen o s s collected durin e 1992-199gth 4 joint Russian-Norwegian expedition e Karth ao t sSea , covering relevant categorie f environmentao s l matrices: sediment, sea water and seaweed. For each exercise, results were requested to be reported for 239+240 I37 basie th p u- ca tgrou leas d Srf radionuclideCpto 90 ,san s which have been routinely analysed and reported for Kara Sea environmental samples. The radionuclide concentrations intercomparisoe inth n samples were representativ levele th f eso generally encounteree th n di Kara'Sea. Detailed resultintercomparisoe th f so n exercise reportee sar Joine th tn d i Russian - Norwegian Experts Group reports on the 1992, 1993 and 1994 expeditions [60,17, 52]. thess A e exercises were organise smala r dfo l numbe laboratoriesf ro , their purposs ewa not to define reference values for radionuclide concentrations in the respective samples, but rathe checo rt agreemene kth t between results reporte participantse th y de basib e th th f sn o O . intercomparison exercises concludes wa t i , d that, generally reliabilite th , analyticae th f yo l method participatinse useth y db g laboratorie appropriats si tha d laboratoriee ean tth s produce radionuclide concentration data which are in reasonably good agreement. For all three intercomparison materials, the best concordance amongst individual results was obtained for 13/Cs (around 10% standard deviation from the mean for sediment and seaweed, 5% for sea water). Good agreement was also obtained for 90Sr in sea water (10% standard deviation from e verthw th Se ylo r o mean)t concentratio e Du . n sedimen ni e smal th d l an numbet f o r 90 reported results for seaweed, it proved difficult to evaluate the participants' performance in these cases. For 239+240Pu, the agreement is not as good (up to 25% standard deviation from the mean) reflecting the analytical difficulties associated with its determination in environmental matrices. 3.3.6. Conclusion radionuclidn so e inventorie Kare a th an Se si On the basis of the extensive joint Norwegian-Russian data [17, 45, 47, 49, 51, 52, 54, , 59-6455 , othed IAEA-MEf an 53 ] o r, d 60result50 an ], 48 s , L e store 47 [18th , n di ,44 GLOMARD database [36] measuremenn ,o f concentrationo t f severao s l radionuclides (3H, 60 90 129 I37 238 239+240 241 Co, Sr, "Tc, I, Cs, Pu pu and Am) in water, sediment and biota sampled at the major dumpsites in Abrosimov, Stepovoy and Tsivolka Fjords and the Novaya Zemlya Trough as well as in the open Kara Sea and the Ob and Yenisey estuaries, it can be concluded that, wit exceptioe hth f limiteno d area Abrosimon i s Stepovod van y Fjords, only minor contamination exists relativ backgrouno et d levels. In-situ gamma-spectra recordee th t a d dumpsites indicate thacontaminatioe th t localizea s nha d character and t site,a s outside eth disposal areas contributioo n , n from local source observee b n sca d [16, 18]mose .Th t marked contaminatio sedimenf no t appear associatee b o st d with leakage from dumped containert sbu this is confined to the immediate vicinity of the containers. The ope nrelativels i Kar a aSe y uncontaminated maie th , n contributions o t bein e gdu direct depositio catchmend nan t runoff from global fallout cause nucleay db r weapons tests, discharges from reprocessing plant Western si n e formeEuropth d rean Soviet Union, local fallout from tests performe Novayt da a Zemly Chemobyd aan l fallout [62-64]. 51 4. DISTRIBUTION COEFFICIENTS AND CONCENTRATION FACTORS Obtaining basic information on the potential uptake of contaminants by marine particles and biota is fundamental to an evaluation of the transport pathways and risks posed by waste- derived radionuclides in the Kara Sea. The concepts of distribution coefficient (K IQs are used by numerical modellers in their models of radionuclide dispersion to establis partitionine hth f radionuclidgo e concentration between paniculatea mattese d an r water. Concentration factors are used to establish the partitioning between marine biota and sea water radionuclide concentrations regardless of the pathways by which these radionuclides are taken up. t knowno r mane fo nar yF e ocea e areaC actuath d f d Th an no s an l d valueK r fo s furthermore they vary spatially and temporally and are often affected by environmental and biological variables e Arcticth r ,Fo . date particularlar a y sparse because acces s beeha s n limited until recently. With little field data available, modellers have relie n valueo d s published by IAEA [65]. IQs in this report were estimated from both stable element geochemical data and the proportions of the particulate phase abundance of the elements that are likely to be exchangeable with the aqueous phase. CFs were computed using field measurements of radionuclide and/or stable element concentrations in organisms as well as data derived from laboratory radiotracer experiments. This chapter describes results of laboratory and field work aimed at elucidating environmental parameters that might affec valueF C t r arctid K 4.1. DISTRIBUTION COEFFICIENTS The uptake potential for radionuclides on suspended or deposited particulate matter (sediment marinn )i e system functioa relative s si th f no e influenc chemicae th f eo l properties of the radionuclides, sediment characteristics and the moderating influence of the environment e unitlesTh . s parameter use quantifo dt y this potentias i d an knows i d l K s na 1 defined as the ratio of the concentration of radionuclide on sediment (Csed, in Bq/kg"" dry 1 weight) and in water (Cwater, in Bq kg" ): Ged A paucity of data on K 52 investigation, conducted in summer 1995, in which Kds for caesium, americium and cobalt were determinelocations5 3 t a a se .t da In radionuclide dispersion models, a parameter known as the partition coefficient is used to establish the equilibrium between radionuclide concentrations in sediment and seawater. The partition coefficient for sea water (PCW) ranges from zero to one and is a function of Kd and suspended matter concentration C. It is defined in dispersion models as: >c.=-4^- where PCW represents the fraction of the total radionuclide activity in a parcel of water which remain s clos i solution n i s W oneo et PC f ,I . the ne radioactivit mosth f o t s predicteyi o dt remain dissolved in sea water; if PCW is close to zero then most of the radioactivity is expected attaco t sedimentso ht . With little field data available for Kd and C, a risk analysis was conducted to determine range th valuef eo s predicte partitior dfo n coefficients analysie Th . conductes swa d usine gth IAEA estimated [65K ] primarr sfo y waste-related radionuclide frod expectee san m th d ranges Novaye th r fo ao fC Zemly aopee Fjord th defin nC d Kard e san eth an rangee ad SeaTh K f . so precision of PCW used in the models. The analysis illustrates that for caesium and strontium modellers must accept a 20% variation in PCW. The ranges are much greater for the other waste-related radionuclides (Fig. 29). Partition coefficient alse ar so sensitiv suspendeo et d matter concentration. For all radionuclides, higher suspended matter concentrations in the fjords resulte lowen destimatei W rPC s (Fig. 30). 4.1.1. Results of laboratory experiments As a result of the difficulty in accurately defining partition coefficients based on the IAEA [62] estimates alone, laboratory experiments were subsequently develope asseso dt e sth influence of key environmental parameters operating in the Kara Sea which might account for some of the uncertainty in the values of Kd, C and hence PCW. Experiments were conducted to examine the influence on Kd of changes in the ionic strength of sea water, suspended matter concentration and temperature using Kara Sea water and surficial bottom sediments collected from Abrosimov and Stepovoy Fjords during a 1994 joint Russian-Norwegian expedition. determine s rangd e K Th f eo thesn di e experiment eacr sfo h radionuclid gives ei Tabln i . eIV In respons o experimentaet l fluctuation n salinityi s , notable change n distributioi s n coefficients were observed at low salinities (0-10%o) only. The salinity of Abrosimov Fjord and Stepovoy Fjord watert expecteno e sar decreasdo t e below 15%o suggesting that variations in salinity at the dumpsites need not be considered. Suspended matter concentrations in the fjord Novayf o s a Zemly likele aar fluctuato yt e withi range nth e typically measure coastan di l fjords; i.e. 10s to 100s of mg/L. As previously predicted, such large variations are expected to play a significant role in the sorption behaviour of radionuclides. Indeed, in laboratory experiments, Kd values for several waste-related radionuclides (Am, Co, Ru and Sr) were sensitiv fluctuationo et concentration si suspendef no d matter. 53 Partition Coefficient o O O O O 5-8 Ni it>. Ol (DO 3 1 &r <* ^ 3 T; Co H 3 S?' ^ •>• *^1 C^ ^j ^) a. S g- % a C> a 5 & CD ^ CO QJ *<- —1 a en °> s U) CD a, ID Partition Coefficient ^ p p 0 p P ~^ o r £» b 05 CTi cc b ! \ » i* I — o • y/ to x cn 3 cn S- — o <*' 3". 0s- »•»*. ~~ cn 5' j. a O //, ^ ^ <^ tr +*+ * ^^ 8 "a O : r T t3- ?> I! —o •* I/ —— / SA x^x ,' • '/ H J /// CD y/ _D Oa TRO" ^ — *° C O a. I 01 CD r ^~*- r^ a S *^k **<, - n O ^ ~ ° £ s. — cn "O TO 5 CD sl o — o O S 0 Q s. | TO 3 1 "—O ss Xxv L^ S" v// ^ ; a l22i p«*. m K) a0 cn ^ cn a ~ o a a. KJ ~ cn J-. >* _^ — o 0 TABLE IV. IASAP SELECTED KdS FOR MODELLING COMPARED WITH EXPERIMENTAL DAT IAED AAAN VALUES Fjords3 IAEA0 IASAP Stepovoy Abrosimov Kara Sea [65] Selected Valuesd Americium (0.1-1) x 106 (0.1-3 6 10 (0.1-4 )x 5 10 )x 1 x 105-2x 107 1 x 106 Plutonium 0.5-1 x 105 0.5-1 x 105 e0.2-5 10 5x 1 x 104-1 x106 1 x 105 Cobalt (1-2) x 106 (1-2) x 103 (0.5-5) xlO4 x 102 4-1x 106 6 10 x 1 Europium (1-2) x 105 (1-2) x 105 1 x 105 110x 5-2x 106 7x 105 Strontium (0.1-1)x 102 (0.1-1) x 102 e(0.1-5) x 101 1 x 102-5x 102 3 10 x 1 Caesium (3-6) x 102 (2-3) x 102 0.15 x 102 1 x 102-2x 104 5x 103 a Laboratory experiments. b Shipboard experiments. c Coastal sediments. d Used in IASAP model calculations. Estimated Kj ranges based on measured radionuclide concentrations in water and sediment samples. e Temperature affects the rate and endpoint of all chemical exchange reactions. Because fundamentallQ I y represent e equilibriuth s m endpoin a chemica f o t l reaction, colder temperatures in arctic waters (-4 to 4°C) may result in different equilibrium K From these experiments elucidatin e effec th f go salinityt , suspended matter concentration and temperature on IQ, only suspended matter concentration and the grain size s observewa importante b o dt largA . s emeasure differencwa , r sedimentCo d fo r K 4.1.2. Results of field experiments A drawback of conducting laboratory studies to understand the influence of environmental parameters on Kj is that, after sample collection, changes begin to occur to sedimena watese s thesa d r an et environmental materials age. Experiments shoule b d conducte soos da possibls na e after sample collection. This limitation poses difficulties when 56 conducting research in remote areas such as the Arctic. A second limitation of laboratory investigations is that typically only a few water and sediment samples are collected. This limits the extrapolation of results determined for a limited number of sites to a large region Kare sucth as h a Sea responsn I . theso et e limitations determinationd K , usina se t gsa freshly collected materials were conducte 199 n dJoinpari s a a 5f to t Norwegian—US expedition. Batch experiments were conducted using 241Am, 60Co, and 134Cs radionuclides which exhibit varying degrees of particle affinity. Partition coefficients (PCW) may be calculated directly from the experimental data. These data confirm the finding of the laboratory experiments that distribution coefficients and partition coefficients both exhibit a wide range of variation for the Kara Sea. Caesium is the only radionuclide exhibiting a well-constrained Kd [(0.1 0.04± 2 m3/kg) solutionn i ] wit% h99 . 4.1.3. Conclusions on distribution coefficients three-phase Th e approac renderes hha d site-specific informatio valued K theid n san no r range uncertaintyf so . (1) Theoretical: The results of a risk analysis conducted by computer simulation demonstrate tha twaste-relatee mosth f o t d radionuclides e residin ar Kare a th aSe n g i expected to exhibit large ranges of variation for PCW- The only exceptions are radionuclides with low Kd, i.e. caesium and strontium. (2) Laboratory: From laboratory experiments suspended matter concentratio sedimend nan t characteristics were identified as the most important sources of variation for Kd. The effects of temperature and salinity fluctuations on Kd are negligible. (3) Field based: Field based determinations fro location5 m3 Kare confira th aSe n si m that KdS exhibi wida t e rang f valueeo responsn i s variablo et e environmental conditions. Partition coefficients calculated directly from the field data demonstrate that the modelling parameter, PCW, will vary significantl responsn yi suspended botan o e t d hK d matter concentration in the Kara Sea. Appropriate ranges of both Kd and suspended matter concentration values therefore mus e examineb t e radionuclid th s par a df o t e dispersio d risan nk assessment modelling investigations. Experimentally-determined Kd values for Novaya Zemlya Fjords and the open Kara Sea are give Tabln i . eIV 4.2. CONCENTRATION FACTORS The radioactive wastes disposed on the sea floor of the Kara and the Barents Seas in recen releasee t b yeary sma d from their containers, leadin potentiao gt l contaminatioe th f no fauna living on the sea bottom. Released radionuclides may be retained in benthic organisms and then transferre highea o dt r trophic Arcti e leveth f o lc marine foodchain. Realistic models for assessing biological uptake under Arctic conditions require precise estimate rate f th e o f so transfer of key radionuclides from sediment or sea water to organisms representative of the Arctic community [64]. Since little is known about radioecological processes in Arctic marine foodwebs, laboratory experiments were carried out on benthic organisms. The objectives of 57 these experiments were to select sentinel organisms and evaluate transfer factors and concentration factor varieta r fo sf radionuclide yo s selecte basie th f estimateso n do d waste inventories for the Kara Sea. 4.2.1. Cs and Co transfer factors for Arctic clams 137 60 Transfer factors (TF) were evaluated in order to define the fraction of total contaminant availabl accumulatior efo n from sedimen benthiy b t c organisms. Arctic speciee clamth f so s Chlamys islandicus were maintaine aquarin di a reproducin environmentae gth l conditionf so Abrosimov Kare Fjor(2°Ca th aSe n di , 35%o salinity, bulk sediment collected fro uppee mth r 10 cm). Afte day9 7 rf exposur o s contaminatee th o et d sediment, clam sedimend an s t were collected for gamma-counting and TF were computed as follows: _ Adam A•sed 1 where Aciam and Aseci represent the measured activities in Bq kg" dw. Activities in the soft parts of the organisms were very close to the detection limit; therefore obtaineF T e th , d were long-livee lesth sr thafo 0 nd1. 0.0radionuclided 1an s 137Cs and Co, respectively. These result similae sar thoso rt e previousl yuptak m reporteA er dfo 60 1 24 by benthic bivalves from temperate latitudes. 4.2.2. Concentration factor Arctir sfo c benthic organisms As previously reported, the benthic communities of the Kara Sea are dominated by brittle stars (echinoderms). Bivalve mollusc browd san n algae, presen shalloe th n i tw Arctic marine environment, have been routinely used in temperate latitudes as biomonitors of both radionuclide and trace metal pollution. Hence, short term exposure experiments (12 days) were conducted with these organisms (i) to assess the validity of extrapolating CF obtained under temperate conditions to Arctic ecosystems, (ii) to help model the radiological impact of pulsed contaminant exposures (e.g. leakage from dumped nuclear reactor r wasto s e containers) and (iii) to select benthic organisms as bio-indicators of radionuclide contamination and dispersion in the Arctic Seas. The experimentally-derived concentration factors are defined as: organisA —, pm_ 1 where Aorganism and Awater represent the measured concentrations in Bq kg" wet weight and Bq kg"1 water, respectively. Accumulation and depuration rates of radiotracers of key radionuclides were compare (typicaC Arctie 2° th t f da co t l 12° a Seas d Can )(typica f o l temperate seas) for the macroalga (Fucus vesiculosus) [68] and the brittle star (Ophiothrix fragilis] [69]. Result presentee sar , respectivelyVI Tablen dd i an sV . 58 TABLE V. CFs IN FUCUS VESICULOSUS COMPARED TO CF IN MACROALGAE Waste Radiotracers CF (2°C) CF (12°C) CF Radionuclides [65] 137Cs 134Cs 3.3 ±0.3 4.6 ±0.9 30-100 60 57 Co Coor 241+6 186 ±43 — • 60Co 101 ±6 353 + 23 1000-10000 241Am 24IAm 329 ±10 3 7 + 7 43 5000-10000 152 152,,54,155Eu Eu 478 0±3 614 ±67 300-5000 106Ru 88 + 6 * 300-5000 109 Cd 51±3 286 ±21 1000-10000 133Ba 9 + 0 21 298 2±1 10-30 * The experiment was not completed due to insufficient Ru tracer available. TABLE VI. CF IN OPHIOTHRIXFRAGILIS Waste radionuclides Radiotracers CF (2°C) CF (12°C) 137Cs 134Cs 3 4 60 S7/-1,. Co C°org 69 360 60Co 16 29 241Am 241Am 48 53 I06Ru 9 10 109 Cd 34 46 I33Ba 1 2 t 2°C A valueF ,C Fucusr sfo vesiculosis were highes followe u , CoE , r orgAm fo tBa , y db Coinorg, Ru, Cd and Cs, in that order. The general order of accumulation at 12°C, Eu > Am > s somewhawa , Co> Cs d or> gtC differen> Co a inorB > g t from tha tespeciall C note2° t da r yfo the two Co forms. The CF values generated from both experiments ranged over two orders of magnitude, from several hundred for Eu, Am, Coinorg Ba, Cd and Coorg to less than 5 for Cs. 60 109 Thercleaa s re wa influenc f temperatureo accumulation eo f nCoo e d inorth C an ?t da 12-e th en df d o experiment , whereb finae yth l concentration facto significantls wa r y greatet ra 59 the higher temperature (p < 0.001). As supported by the literature, the temperature effect noted for Coinorg uptake might be a consequence of the oxidation (mediated by bacteria and enhance t higheda r temperature f Co(IIo ) Co(III))o t ) mora , e particle-reactive th form r Fo . remaining tracers, temperatur significano n d eha t influence Th 0.00 < . p ( eCF 1 e levelth n o ) CFs obtained at 12°C for most of the radionuclides in these experiments were lower than values literature citeth n di e [65] probabld ,an y reflec face th tt thaliterature th t e values were based on long term chronic periods of exposure rather than short term laboratory exposure experiments. For the brittle star (Ophiothrix fragilis) radionuclide CFs obtained at the end of the 57 uptak ed 12° perioan presente e C3 ° daysC ar 2 Cos (1 d2° t ora t )wa g A Tabln i d . VI e 241 I09 60 I06 concentrate greatese th o dt t degre fragilis. O y eb followey db Am , Cd, Coinorg, d Ruan Cs. Ba was not concentrated at 2°C. The general order of accumulation was the same at 134 133 12°C tracerl Al . s were concentrate greatea o dt r degre highee th t ea r temperature, with organic 5'Co showing the greatest response to temperature. After 13 days of uptake, there was no significant differenc 0.05bode < th p ( eyn ) i distribution (arm discd an f sradionuclid o ) e concentrations. Increase accumulation si n rate highet sa r temperatur partialle b o t y e ema y du increased metabolic activity (animals observed to be much more active at 12°C than at 2°C). For the seaweeds, depuration of the radionuclides was followed daily over 14 days at 2°C and 12°C. Linear regressions for radionuclide loss were calculated for the exponential portio lose th sf ncurvo e betwee depurationf o 4 1 n d dayan .s2 Elimination rates obtainet da 2°C were significant (p < 0.05) for 241Am, 133Ba and 152Eu. At 12°C significant rates of depuration were obtained for Ba, Cs and Co. Ba was rapidly eliminated by F. 133 134 60 133 vesiculosus, wherea othee th s r radionuclides remained relatively firmly boune algath .o dt Considerin entire gth e 14-d depuration experimen exponentiae t (firsth day o d tw tsan l portion lose ofth s curve) percentagee ,th timf so e zero activity retaine elementl al r dfo s d excepan a B t Cs ranged between 71% (Eu) and 91% (Cd) at 2°C, and between 85% (Cooro.) and 100% (Eu t 12°a ) anCdCd (Table VII). TABLE VII. RADIONUCLIDE ELIMINATION DAT FUCUSR AFO VESICULOSUS Waste Radiotracer retaine% d aftes day4 1 r s Biological Radionuclides half-lives (days) 2°C 12°C I37Cs 134Cs 53 ±6 72 ±17 96 60 57<~i^ Co C°org 82.5 ±1.9 5 85±2 106 60Co 90 ±12 92 ±5 540 241Am 241Am 85.6 ±4.4 92 ±13 80 I52 152,154,155Eu Eu 71 ±8 100 ±1 27 106Ru 89.9 ±4.4 — 99 109 Cd 91 ±9 101 0± CO 133Ba 30.4 ±2.7 32.5 ±3.6 9 60 Compared to other radionuclides the retention values obtained for Cs and Ba were much t 12°Ca % ,32 respectively d t an 2°Ca % % ,72 lower30 . d Temperatur,an viz.% a 53 d eha significant effect only (p < 0.001) on retention of Eu. An explanation for the greater Eu 152 I52 elimination observed at 2°C is not immediately evident; however, it may be related to morphological and biochemical changes taking place in the fruiting algae at 12°C which, in turn, could result in enhanced retention of the radionuclide. Durin e exponentiagth l phas f depuratioe o days 4 1 o )t correspondin2 n( "lone th go gt 241 152 134 60 133 term" loss pool, only Am (2°C), Eu (2°C), d CCoan s inorg (12°C)d an d ° Ban , a(2 12°C) were significantly released case th f eo n BaI . , rapid depuration resulte vern di w ylo 133 percentages retained afte4 days1 r . Therefore, 133Ba, like 134Cs, doe t appeae no b s o t r accumulated and retained in F. vesiculosus, unlike the other radionuclides which are relatively firmly bound to the brown algae. Biological half-lives computed for the depuration rate constants presented in Table VII, show that values ranged from 9 days for Ba to infinity for !33 109Cdatboth20Candl2°C. For the brittle star, radionuclide depuration was followed daily over 14 days at 2°C and 241 60 12°C. Am and Coinorg were significantly (p < 0.05) eliminated from the brittle stars at 2°C. At 12°C, only the loss of inorganic 60Co and 134Cs was significant at the p < 0.05 level. As there was no significant difference in long term loss rates at 2°C and at 12°C, temperature variations withi range nth e examined woul t exerdno majoa t r influencn eo excretio radionuclidef no s accumulated fro watea m se ophiuroids y rb . The retention times obtaine werC 2° e t da ver y long. Biological half-lives wert no e 241 different from infinity for most radionuclides except Am (Tb1/2 = 16 days) and inorganic Co (Tb,days)9 1 = , supportin viee gth w that ophiuroids efficiently retai recorna theif do r 60 /2 exposure to soluble radioactive contaminants. 4.2.3. Concentration factors for a Kara Sea bivalve A long term exposure (1 month) laboratory uptake study was performed under Arctic conditions using a bivalve mollusc {Macoma) collected from Abrosimov Fjord sediment in Kare th a Sea. This benthic organism deposit-feedea , r livine th f go burieuppee m c th 0 n d1 ri sediment, was exposed to a relatively constant source of the contaminant radionuclides 60Co, Cs and Am in sea water. After 36 days of exposure, accumulation of these radionuclides 134 241 reached steady state only for Cs. Concentration factors obtained for Am, Co and Cs 134 241 60 134 were , respectively380,3014 d an 0 r 241 60d Fo A.Co man , these concentration factore ar s somewhat lower tha valuee nth s reporte literature th n di temperatr efo e zones. Compared wit activitiee uptakhe th th f o e sd period measureen e e clae th th , th t m a n d i percentage radionuclidf so e retained afte day0 8 rdepuratiof so 24!r nAmfo wer% , 84.5e88 % for onld Coan y 7.5r %fo Cs . Radionuclides were mainly locate sofe th t n dtissuei r fo s 60 134 241 Am (60%), in the shell for 60Co (90%), and were equally distributed between shell and soft tissue I34r fo sCs . Therefore, once accumulated fro watera mse , 241 60Ad Cman o will remain tightly bound to the clam. The Am located in the soft tissues has the potential for trophic 241 transfe higheo rt r levelfoodchaie th f so n through predation, whereas 60Co, mainly adsorben do shell, would be less available for biological uptake. 134Cs is concentrated from sea water to a rapidl s ver degrei clae w d yth lo m an y y eb eliminated. Therefore, l34Cs would remain mainly dissolvee inth d forwould m an t readil dno y ente fooe th r d chai consumptioa nvi f thino s bivalve. 61 4.2.4. Conclusions on concentration factors Give paucite nth f informatioyo bioavailabilite th n no wastf yo e radionuclidew lo t a s temperatures in the marine environment, the findings of the short term experiments should be useful in modelling the radiological impact due to leakages from nuclear reactors or waste containers dumped in the Kara Seas. The main conclusions of the studies are: (1) Previous CF data obtained under temperate conditions should be applicable to the Arctic ecosystem for the benthic macroalga (Fucus vesiculosus), since there is no temperature waste effecth r efo tradionuclide s tested except with inorganic 60Co. Nevertheless, care must be taken in ensuring that the same environmental conditions (e.g. salinity, light intensity and duration of the exposure) are considered when extrapolating these results 60 to Arctic waters. For Coinorg, very low temperatures (2°C) could decrease bioconcentratio (Fucusy nb vesiculosus) possibly through greatly reduced microbially- mediated processes. For the brittle star (Ophiothrixfragilis), CFs obtained for Am and organi inorganid can undeo cC r temperate condition t applicablno e Arctie ar sth o et c ecosystem. ) (2 Once accumulated from water, contaminant lose b nearlt a ty sma y identical rate hign si h and low temperature regimes by both seaweeds and brittle stars. 133Ba, I34Cs, 152Eu and 24 'Aeliminatee mar Fucusy db vesiculosus whereas 106Ru, Co-cobalamine, inorganic 60109d CCoan d remain tightly bounbrowe th o dbrittlt e n th alga r e Fo .sta r (Ophiothrix fragilis) e radionuclideth mos f o t s (except 24I d inorganiAman c 60Co) wert no e significantly eliminated. Long retention times should increas potentiae eth r trophifo l c transfer of these contaminants to predators such as grazers or flatfish for seaweeds and brittle stars, respectively. purpose th r monitorinf Fo (3eo ) g radioactive contaminatio dispersiod nan Kare th an i Sea, the seaweeds (Fucus) and the molluscs (Macoma} are recommended for use as bio indicators. Recommended CFs for the Arctic ecosystem are given in tables VIII and IX. TABLE VIII. RECOMMENDE BIO-INDICATORR FO s DCF S Brown Seaweed Bivalve Ophiuroid Fucus1 Macoma2 Ophiothrix1 ° 10 x 1 3x 10° 3x 10° 1 x 102 3 x 102 2x 10' 2.4 x 102 7x 10' 4.7 x 102 2 10 x 4 3.3 2 x 10 5x~"lO1 8.8 x 101 9x 10° 5x 101 1 x 10° 2.1 x 102 8x10'3x 10' weeks2 1 . 2 1 month. 62 TABLE IX. SELECTED CFs FOR MODELLING COMPARED WITH EXPERIMENTAL DATA AND IAEA VALUES11 Fish Sea Birds Marine mammals IAEA IASAP (muscle) [65] Selected value fishr sfo b Fish (muscle) Pu (1-410'-1.5x <2 )2 xlOx10 3 3 SxlCT'-lxlO2 4x10' Cs (0.3-3) xlO2 (0.04-1.13 10 )x 2 10 x (0.13-1.81 2 10 )x (0.1-3 2 10 )x Sr ' 10 (2-9 x ) 0.4-3 (0.3-1) x 10' 4 Ni 1 x 102 7xl02 (0.05-1) x 103 1 x 102 Sb - - 1x10-' (0.1-13 10 )x a This tabl bases ei datn do a provide experty db . Boissons(F . CarrollJ , . Fisher . FowlerN , W . S . ,Rissanen K , . SalbuB , , K-L. Sjoeblom . SazykinaT , ) participatine th n gi IASAP Consultants' Meeting organized in Monaco from 27-29 November 1995. b Used in IASAP model calculations OJ 5. CONCLUSIONS e basiO th nf comprehensiv o s e investigation f environmentao s d radiologicaan l l condition e Arctith n i cs Seas carrie t durinou d e yearth g s from 1992-1996e b n ca t i , concluded t bee tharegioe no th tn s affecten ha dumpine th y db radioactivf go e wastee th n si Kar Barentd aan s Seas. From the data stored in the GLOMARD database on the measurement of concentrations of several radionuclides in water, sediment and biota sampled at the major dumpsite Abrosimovn i s , Stepovo Tsivolkd yan aNovaye Fjordth d an as Zemlya Troughs a , well as in the open Kara Sea and the Ob and Yenisey estuaries it can be concluded that, with the exception of limited areas in Abrosimov and Stepovoy Fjords, only minor contamination exists relativ backgrouno et d levels. In-situ gamma-spectra recorde dumpsitee th t da s indicate thacontaminatioe th t localizea s nha d character and t site,a s outsid disposae eth l areaso n , contribution from local sources can be observed. The most marked contamination of sediment appear e associateb o t s d with leakage from dumped container t thi s confinebu si s e th o t d immediate vicinity of the containers in cases where suitable measurements exist. The open relativels i Kara aSe y uncontaminated maie th , n contributions direco beint e tgdu deposition and catchment runoff from global fallout cause nucleay db r weapons tests, discharges from reprocessing plant Western si n Europformee th d rean Soviet Union, local fallout from tests performed at Novaya Zemlya and Chernobyl fallout. concepte Th f distributioso n coefficient (K 64 REFERENCES [I] YABLOKOV, A.V., KARASEV, V.K., RUMYSANSEV, V.K, KOKEEV, M.E., PETROV, O.J. LYTSOV, V. N. YEMELYANENKOV, A.F., Facts and Problems Relate Radioactivo dt e Waste Disposa e Seath sn i lAdjacen e Territorth e o th t t f yo Russian Federation, Office of the President of the Russian Federation, Moscow, Small World Publishers, Albuquerque (1993). 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Bull, (in press). [68] BOISSON, F., HUTCHINS, D.A., FOWLER, S.W., FISHER, N.S., TEYSSIE, J-L., Influence of temperature on the accumulation and retention of eleven radionuclides by the marine alga Fucus vesiculosus (L.), Marine Poll. Bull, (in press). [69] HUTCHINS, D.A., TEYSSIE, J.-L., BOISSON, F., FOWLER, S.W., FISHER, N.S., Temperature effects on uptake and retention of contaminant radionuclide and trace metals by the brittle star Ophiomrix fragilis, Marine Environ. Res. (in press). 69 CONTRIBUTORS TO DRAFTING AND REVIEW The following IAEA staff members contributed to drafting and review: Ballestra, S. Baxter,. M.S. Boisson, F. Carroll, J. Fowler, S.W. Gastaud, J. Gayol, J! Gustavsen, C. Hamilton. L , Harms. ,I Huynh-Ngoc. L , Liong Wee Kwong, L. Miquel, J.-C. Oregioni, P. Osvath, I. Parsi, P. Povinec, P.P. Scott, E.M. 71