Recent changes in levels of persistent organochlorines and mercury in eggs of seabirds from the Barents Sea

Environmental Pollution, Vol. 92, No. 1, pp. 13-18, 1996 Copyright © 1996 Elsevier Science Ltd Printed in Great Britain. All fights reserved 0269-7491/96 $15.00 + 0.00 ELSEVIER

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RECENT CHANGES IN LEVELS OF PERSISTENT O R G A N O C H L O R I N E S A N D M E R C U R Y IN EGGS OF SEABIRDS FROM THE BARENTS SEA R. T. Barrett, a J. U. Skaare b & G. W. Gabrielsen c* aDepartment of Zoology, Tromso Museum, University of Tromso, N-9037 Tromso, Norway bDepartment of Toxicology and Chemistry, Central Veterinary Laboratory~Department of Pharmacology and Toxicology, Norwegian College of Veterinary Medicine, PO Box 8146 Dep., N-0033 Oslo, Norway CNorwegian Institute for Nature Research, c/o Tromso Museum, University of Tromso, N-9037 Tromso, Norway (Received 22 May 1995: accepted 2 October 1995)

Abstract

found for any of the contaminants. Nor were there any consistent geographical differences. Recently, considerable emphasis has been put on studies and monitoring of contaminants in the environment, both nationally and internationally. The 1983 exercise was therefore repeated a decade later in order to document any further changes in OC levels in North Norwegian waters and is the basis for this study. Because the study was carried out as part of the Arctic Monitoring and Assessment Programme (AMAPproject 13 in Kristjansson & Kielland, 1994), the geographical range was extended to include Svalbard. Long-range transport of contaminants to high latitudes has been documented (Nettleship & Peakall, 1987; Hargrave et al., 1992) and very high levels of PCBs have been detected in glaucous gulls Larus hyperboreus breeding on Bear Island (Bourne & Bogan, 1972; Gabrielsen et al., 1995). An incidental collection of eggs on Kharlov, an island off the Kola Peninsula was also included as there are few data of this kind published from this region (Savinova, 1991).

Eggs of ten seabird species were collected from six regions in North Norway, Svalbard and N W Russia in 1993, and were analyzed for organochlorines (OCs) and mercury. Significant declines in levels of PCBs, p,prDDE, HCB, /~-HCH, "~-HCH and oxychlordane were documented in nearly half the data set since a similar study in 1983 in six of the seabird species breeding in North Norway. Only four of the 90 paired data sets increased significantly, and the remainder remained unchanged. There was very little change in mercury levels. The decline in OCs corresponds to similar declines found in Canada and the Baltic Sea, and to declines documented in marine fish in a Norwegian fjord. They can all be attributed to the reduction in use and spread of contaminants, both in Norway and internationally. No consistent regional differences in residue levels were found. Keywords." Seabirds, eggs, Barents sea, organochlorines, mercury. INTRODUCTION Recognizing eggs as a good source of tissue samples for routine analyses (Walker, 1992; Furness, 1993), eggs of seven seabird species from four regions in North Norway were collected in 1983 and analyzed for organochlorines (OCs) and mercury to investigate possible temporal changes since a similar analysis in 1972 as well as geographical differences in pollutant levels (Barrett et al., 1985). In these earlier studies, the main OCs found were PCBs, p,p'-DDE and hexachlorbenzene (HCB) and all were at concentrations below those at which breeding could be expected to be affected (Barrett et al., 1985). Mercury levels were also low. Although some OC levels measured in 1983 were lower than in 1972, no consistent temporal trends were

MATERIALS AND METHODS

Ten eggs of gannets Morus bassanus, shags Phalacrocorax aristotelis, eiders Somateria mollissima, herring gulls Larus argentatus, glaucous gulls L. hyperboreus, kittiwakes Rissa tridactyla, common guillemots Uria aalge, Brfinnich's guillemots U. lomvia, razorbills Alca torda and puffins Fratercula arctica were collected in 1992 and 1993 from one or more of the four regions sampled in the 1983 study: (A) East Finnmark (Horney); (B) West Finnmark (Hjelmsoy); (C) South Troms/North Nordland (Bleiksoy, Skarvklakken); and (D) Lofoten (R~st). Eggs were also collected off the Kola Peninsula (Kharlov, region E) and from Svalbard (Bear Island and Spitsbergen, region F) (Fig. 1). The eggs were collected randomly among the nests in each colony and only one egg was collected, again at random, from nests of multi-egg species.

*Present address: Norwegian Polar Institute, Postbox 399, N-9001 Troms~, Norway. 13

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R . T . Barrett et al.

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To enable a direct comparison with the 1983 data, the eggs were analyzed for OCs in the same laboratory at the Norwegian College of Veterinary Medicine. Details of the fat extraction and clean-up procedures and the gas chromatographic determination are given in Gabrielsen et al. (1995). However, in the present study, the capillary column was a 60 m, 0.25 mm i.d., 0.25 #m film thickness SPB-5 column (Supelea Inc., Bellefonte, PA, USA). The column temperature programme was: injection temperature 90°C (3 min hold), 25°C min -1 increasing to 180°C (2 rain hold), 1.5°C min -1 increase to 220°C (2 min hold), 3°C min -l increase to 275°C (10 min hold). Quantification was by comparison with individual standards of PCBs made from powder (Promochem, Wesel, Germany) and pesticides (CPM from Cambridge Isotope Lab., Woburn, MA) and were carried out within the linear range of the detector. Recoveries of pesticides and PCBs varied from 86 to 113%. The laboratory has participated in several interlaboratory analytical quality assurance tests organized by WHO/UNEP in 1992, ICES/IOC/OSPARCOM in 1989-1995, and the analytical quality for determination of selected PCB congeners and pesticides was tested and found acceptable. The reproducibility of the PCB levels in the laboratory's own reference sample was tested and found acceptable (n=8, 90.9+7.4% of true value). Although the analyses of the 1983 and 1993 samples were done in the same laboratory, the techniques used did, however, vary slightly. In 1983, packed gas chromatograph (GC) columns were used (Barrett et al., 1985), whereas capillary GC columns were used in this study. To control for any possible differences in the results inherent in the techniques, 25 samples were analyzed in parallel for ZPCB and p,//-DDE using both capillary and packed columns. There were no significant differences in the means of either data set [t = 0.48 (PCB), 0.89 (DDE), p>0.1]. The 1983 and present results were thus considered to be directly comparable.

Twenty-one PCB congeners were quantified (IUPAC Nos. 28, 74, 66, 101, 99, 110, 149, 118, 153, 105, 141, 138, 187, 128, 156, 157, 180, 170, 194, 206 and 209) as were the following: HCH (a,/3 and 7 isomers), HCB, the chlordane group (oxy-, trans- and cis-chlordane, and trams- and c/s-nonachlor), the DDT group (p,p'-DDE, o,ff-DDD, p,p'-DDD, o,p'-DDT and p,p'-DDT), mirex and dieldrin. The limit of quantification was 0.15-0.72 ng g-i for the PCB congeners, 0.13-0.4 ng g-i for the HCH isomers, 0.1-0.35 ng g-1 for the chlordanes, 0.160.6 ng g-l for the DDT group, 0.5 ng g-I for mirex, and 2.0 ng g-1 for dieldrin, all on a wet mass basis. Concentrations of mercury were determined by hydride generator atomic absorption spectroscopy. The detection limit was 0.01#g g-~ (wet mass). Because of a low variance in the means of the results and due to the high costs of the analyses, only five eggs of each sample were analyzed. The 1983 and 1993 sample data sets were compared non-parametrically using the Mann-Whitney two-sample rank test. The significance level was set at 95%.

RESULTS Twenty-three samples of eggs were analyzed, 19 of which duplicated the majority of the species and regions sampled in 1983 (Table 1). Unfortunately, bad weather forestalled a complete sampling in West Finnmark where only one of the five species was sampled. The main OCs found in the analyses are summarized in Table 1. EPCB is the sum of the 21 congeners while ~DDT and ]Cchlordane give the sums of the various members of the groups listed above. Not all the groups listed in Table. 1 were presented as totals in 1983. To allow direct comparisons to be made, some of their components [e.g. p,p'-DDE and /5- and 7-HCH, the concentrations of which were documented in 1983 (Barrett et al., 1985)] are also listed. No p,p'-DDD or o,p'-DDT were detected in any of the samples, o,p'-DDD was detected in only four samples (0.65-15.18 ng g-l). Other OCs detected were mirex [0.51-18.26 ng g-i in 17 of 20 samples (excluding kittiwakes in region A)] and dieldrin (26-261 ng g-l in 18 of the same 20 samples).

Temporal changes A direct comparison of six data sets from the 1983 and the present studies was possible; EPCB, p,p'-DDE, HCB, /3-HCH, .y-HCH and mercury. Levels of oxychlordane which was not documented in detail in Barrett et al. (1985), but for which raw data were available, was also compared. All data-pairs, except that of mercury, tend towards a downward trend in contamination levels in all species in all regions. Levels of p,p'-DDE and ~-HCH decreased significantly (p < 0.05) in ten and eight (respectively) of the 13 data sets, while those of PCB and oxychlordane decreased in five (Fig. 2). Increases were documented in PCB and p,p'-DDE levels in herring gull eggs in region

Organochlorines and mercury in eggs o f seabirds

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C and in oxychlordane levels in gannet eggs. The remaining changes were insignificant. A statistical comparison with the 1973 data was precluded by the lack of the original 1973 data. Among the data not illustrated in Fig. 2, there was no change in 11 of the 12 mercury data sets. The twelfth decreased significantly. Corresponding figures for E H C H were five significant

Herring gull 12 PCB (ppm)

Kittiwake C. guill. Puffin

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decreases and seven unchanged, and for 7 - H C H nine significant decreases, one increase and three unchanged.

Regional differences

As in 1983, there were no clear regional differences in levels of any of the OCs or mercury (Fig. 3).

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Fig. 3. Regional differences in mean levels (wet mass) of ~PCB, HCB, p,p'-DDE and mercury in eggs of seabirds collected in North Norway in 1993. For A-E, see Fig, 1. Columns with common letters are not significantly different from one another.

Organochlorines and mercury in eggs of seabirds DISCUSSION As in earlier studies of eggs and birds in the Barents Sea (Barrett et al., 1985; Moksnes & Norheim, 1986; Savinova et al., 1995), PCBs were the commonest OC contaminants found, followed by the DDT group, the chlordane group, HCB and the HCHs. The latter were found at very low levels (#g kg-1). The concentrations recorded are also all at the lowest end of the scale of recently published data from Britain, Canada and the Mediterranean Sea (Noble & Burns, 1990; Walker, 1992). The highest concentrations were found in the gulls, Larus spp., but even they were considerably lower than earlier Norwegian data from the south and west coast (Bergstrgm & Norheim, 1986; Moksnes & Norheim, 1986).

Long-term trends As far as we know, this is the first long-term data set from the North Norwegian waters. While the 1983 study failed to reveal any temporal trends since the early 1970s, levels of OCs in nearly half the paired data sets decreased significantly between 1983 and 1993. These are most marked in herring gulls and gannets which contained high concentrations in 1983 but now approach those of the other species. The only exception is the herring gull in region C in which concentrations of PCB, p,p'-DDE, ~-HCH, oxychlordane and HCB increased. For PCB and p,p~-DDE, the increase was significant. A 60-85% decrease in levels of HCB, DDE and PCB is also observed when comparing present herring gull egg data with those collected in an independent study in East Finnmark in 1979-1981 (Moksnes & Norheim, 1986). This is one of few equally long-term studies of contaminant levels in seabird eggs (Olsson & ReutergArdh, 1986; Noble & Burns, 1990; Elliott et al., 1992; Elliott & Noble, 1993) and common to most of them it shows a recent downward trend. For example, concentrations of DDT compounds declined in eggs of Leach's storm petrels Oceanodroma leucorhua, rhinocerous auklets Cerorhinca monocerata, great blue herons Ardea herodias and pelagic cormorants Phalacrocorax pelagicus collected in British Columbia, western Canada, in the 1970s and 1980s (Elliott & Noble, 1993). PCB concentrations also declined in the eggs of rhinocerous auklets, but not in the British Columbian storm petrels or in the Bay of Fundy puffins (EUiott et al., 1992). PCBs also declined in eastern Canadian Arctic breeding fulmars Fulmarus glacialis, kittiwakes and Briinnich's guillemots in 1967-1987 (Elliott et aL, 1992). However, concentrations of DDT did not change between the early 1970s and the late 1980s in eggs of double-crested cormorants Phalacrocorax auritus, herring gulls and razorbills breeding in the St. Lawrence Estuary in eastern Canada (Noble & Burns, 1990). In the Baltic Sea, equally significant declines in DDE and PCB have been documented between 1968 and 1985 in common guillemot eggs (Olsson & ReutergArdh, 1986). On the Murman coast, DDT concentrations in herring gulls also decreased significantly while PCB levels remained unchanged (Savinova, 1991).

17

Both the Canadian and Baltic studies demonstrated how the concentrations of OCs have followed the patterns of OC use in the respective regions. In Norway, DDT was banned in 1970. The use of PCB was restricted in 1971, before its use in open systems was banned in 1980. PCBs are to be phased out completely in 1995. Chlordane was banned in 1967. Although the species studied disperse, some widely, from the breeding colonies outside the breeding season and may thus ingest contaminants outside the region, this study also documents a decline in levels after the use and spread of contaminants was limited at the end of the 'organochlorine era' in the early 1970s (Elliott et al., 1992). Similar declines were documented in seven species of fish in a Norwegian fjord between 1972 and 1982 (Skaare et al., 1985). Why there was an increase in levels of DDE and PCB found in the herring gulls in region C resulting in concentrations higher than in any of the other species is an enigma. It is possible that it reflects what were already relatively low levels in 1983, that they reflect a North Norwegian baseline level, and that we can expect fluctuations around these levels in years to come.

Geographical differences There was no evidence that the eggs collected off the Kola Peninsula were more contaminated than those from the Norwegian mainland. This agrees with Savinova's (Savinova, 1991) findings that the gulls L. marinus and L. argentatus sampled along the Murman coast had small concentrations of OCs in relation to other northern sea regions. Nor were the eggs from Spitsbergen less contaminated. This is corroborated in an analysis of guillemot eggs collected on Bear Island in 1989 which showed residue levels very similar to those of the guillemots in this study (Gabrielsen et al., 1995). The lack of differentiation may reflect: (1) that the birds spend most of the winter and early spring away from the colony and in the same areas as the birds from the mainland: they may thereby pick up similar (small) loads of OCs; or (2) the local conditions around all the colonies are relatively homogenous due to a strong circulation and mixing of the Barents Sea.

ACKNOWLEDGEMENTS This study was financed by the Norwegian Directorate of Nature Management, the Offices of the County Governors of Nordland, Troms and Finnmark, the World Wide Fund for Nature (Norway), Troms~ Museum, University of Tromso and the Norwegian College of Veterinary Medicine, Oslo. Thanks are due to Tycho Anker-Nilssen, Enok Olsen, Gunnar Henriksen, Juri Krasnov and Espen Henriksen for their help in collecting the eggs. Espen Henriksen also analyzed the kittiwake eggs from Hornoya as part of his post graduate study (Henriksen, 1995). All the other eggs

18

R. T. Barrett et al.

were analyzed by Anusehka Polder of the Norwegian College o f Veterinary Medicine, Oslo to whom we are extremely grateful.

REFERENCES Barrett, R. T., Skaare, J. U., Norheim, G., Vader, W. & Freslie, A. (1985). Persistent organochlorines and mercury in eggs of Norwegian seabirds 1983. Environ. Poll. (Ser. A), 39, 79-93. Bergstrnm, R. & Norheim, G. (1986). Persistente klorerte hydrokarboner i sjofuglegg fra kysten av Telemark. Fauna, 39, 53-7. Bourne, W. R. P. & Bogan, J. A. (1972). Polychlorinated biphenyls in North Atlantic seabirds. Mar. Poll. Bull., 3, 171-5. Elliott, J. E. & Noble, D. (3. (1993). Chlorinated hydrocarbon contaminants in marine birds of the temperate North Pacific. In The Status, Ecology, and Conservation of Marine Birds of the North Pacific, eds K. Vermeer, K. T. Briggs, K. H. Morgan & D. Siegel-Causey. Can. Wildl. Serv., Spec. Publ., Ottawa, Canada, pp. 241-53. Elliott, J. E., Noble, D. G., Norstrom, R. J., Whitehead, P. E., Simon, M., Pearce, P. A. & Peakall, D. B. (1992). Patterns and trends of organic contaminants in Canadian seabird eggs, 1968-90. In Persistent Pollutants in Marine Ecosystems, eds C. H. Walker & D. R. Livingstone. SETAC Spec. PubL Series. Oxford, Pergamon Press, UK, pp. 181-94. Furness, R. W. (1993). Birds as monitors of pollutants. In Birds as Monitors of Environmental Change, eds R. W. Furness & J. J. D. Greenwood. Chapman & Hall, London, UK, pp. 86-143. Gabrielsen, G. W., Skaare, J. U., Polder, A. & Bakken, V. (1995). Chlorinated hydrocarbons in glaucous gulls (Larus hyperboreus) at the southern part of Svalbard. Sci. Total Environ., 160/161, 337--46.

Hargrave, B. T., Harding, (3. C., Vass, W. P., Erickson, P. E., Fowler, B. R. & Scott, V. (1992). Organochlorine pesticides and polychlorinated biphenyls in the Arctic Ocean food web. Arch. Environ. Contain. Toxicol., 22, 41-54. Henriksen, E. O. (1995). Levels and congener pattern of PCBs in kittiwakes, Rissa tridactyla, in relation to mobilization of body-lipids associated with reproduction. Cand. scient. thesis, Univ. Tromse, Tromsz, Norway. Kristjansson, K. P. & Kielland, (3. (1994). Arctic Monitoring and Assessment Programme (AMAP). Norwegian Implementation Report 1993. SFT-Report, No. 94:01. Moksnes, M. T. & Norheim, (3. (1986). Levels of chlorinated hydrocarbons and composition of PCB in Herring Gull Larus argentatus eggs collected in Norway in 1969 compared to 1979-81. Environ. Poll. (Ser. B), 11, 109-16. Nettleship, D. N. & Peakall, D. B. (1987). Organochlorine residue levels in three high arctic species of colonially breeding seabirds from Prince Leopold Island. Mar. Poll. Bull., 18, 434-8. Noble, D. (3. & Burns, S. P. (1990). Contaminants in Canadian seabirds. SOE Fact Sheet No. 90-1, Environ. Canada. Olsson, M. & Reuterg~rdh, L. (1986). DDT and PCB pollution trends in the Swedish aquatic environment. Ambio, 15, 103-9. Savinova, T. N. (1991). Chemical Pollution of the Northern Seas. Can. Trans. Fish. Aquat. Sei., N5536. Savinova, T. N., Polder, A., Gabrielsen, G. W. & Skaare, J. U. (1995). Chlorinated hydrocarbons in seabirds from the Barents Sea area. Sci. Total Environ., 160/161, 497-504. Skaare, J. U., Stenersen, J., Kveseth, N. & Polder, A. (1985). Time trends of organochlorine chemical residues in seven sedentary marine fish species from a Norwegian fjord during the period 1972-1982. Arch. Environ. Contain. Toxicol., 14, 33-41. Walker, C. H. (1992). The ecotoxicology of persistent pollutants in marine fish-eating birds. In Persistent Pollutants in Marine Ecosystems, eds C. H. Walker & D. R. Livingstone, SETAC Spec. PubL Ser. Pergamon Press, Oxford, UK, pp. 211-32.