Due to the high organochlorine concentrations reported in Arctic top predators, and the potential transport of contaminants with the drifting sea-ice in the Arctic, organisms constituting lower trophic levels living in association with sea-ice have been proposed as susceptible of uptake of high loads of organic pollutants. The present project studies the organochlorine occurrence in organisms living in the marginal ice zone north of Svalbard and in the Fram Strait. This includes both ice fauna (ice-amphipods), zooplankton, polar cod and different seabird species foraging in the marginal ice zone. Our objectives are to investigate: *The bioaccumulation of organochlorines in ice-associated amphipods in relation to diet preference, spatial variation due to sea ice drift route, size, sampling year, uptake and distribution within the body. *Comparison of organochlorine contamination in pelagic and ice-associated organisms at the similar trophic position, to investigate the effect of sea ice as a transporter and concentrator of pollutants. *Spatial variation in zooplankton species, related to differences in water masses and exposure to first year or multi year sea ice. *The contamination load in different seabirds feeding in the marginal ice zone, in relation to diet choice and estimated trophic position, taxonomically closeness and the induction of hepatic CYP P450 enzymes.
Paremeters measured in addition to POPs: EROD activity and testosterone hydroxylase in seabirds. Stable nitrogen and carbon isotopes (co-operation with Haakon Hop at NP). Radiolabelled PCB to study distribution and uptake in ice fauna. Media sampled: The collection of organisms was conducted during cruises in the marginal ice zone in 1998 and 1999. Samples of calanoid copepods (Calanus glacialis, Calanus hyperboreus), euphausiids (Thysanoessa inermis), pelagic and ice-associated amphipods (Parathemisto libellula, Apherusa glacialis, Gammarus wilkitzkii, Onisimus spp.), fish (Boreogadus saida), and seabirds (Alle alle, Cepphus grylle, Uria lomvia, Rissa tridactyla) were collected. Whole organisms are analysed for all taxa except seabirds, where the liver were analysed for POPs and EROD, and muscle for stable isotope analyses.
1998 September(from multiyear ice): N8133/E2910 Station I N8055/E1504 Station II N8012/E0002 Station III 1999 May (from first year ice): In the sentral Barent Sea and close to Hopen Island. 1999 September (from multiyear ice): N8227/E3255 Station IV N7645/W0807 Station V
Extracts from all the organochlorine analyses are stored at the Environmental Toxicology Laboratory at the Norwegian School of Veterinary Science, Oslo, Norway. The rest of the seabird carcasses not used are stored at the Norwegian Polar Institute, Tromsø, Norway.
Sampling: Calanoid copepods Calanus hyperboreus stage C V and females were collected with MEGA net (1550 m mesh) and Tucker trawl (2000 m mesh). The samples were stored in polypropylene buckets until processed (identified and sorted under stereoscopic microscopes). Euphausiids (Thysanoessa inermis) and amphipods (Parathemisto libellula) were collected with MEGA net (1550 m mesh), Tucker trawl (2000 m mesh) and bottom trawl. The samples were stored in polypropylene buckets until processed (identified and sorted under stereoscopic microscope, length measurements). Ice fauna (Onisimus glacialis, Onisimus nanseni, Apherusa glacialis and Gammarus wilkitzkii) were collected by divers using suction pumps. The ice stations were on floes consisting of multiyear ice. Polar cod (Boreogadus saida) were collected by divers using hand held nets, and by bottom trawl. We measured the total length of each fish, preserved the stomach on 70% ethanol and dissected the otoliths to store them on glycerol. The rest of the fish was frozen whole at -20 deg.C for analysis of POPs. The seabird species were shot, dissected immediately, and stored frosen until analyses. Organochlorine Analysis: All samples for POPs analysis are stored frozen at -20 deg.C in containers of polypropylene. The analysis of organochlorines were carried out at the Environmental Toxicology Laboratory, The Norwegian College of Veterinary Medicine, Oslo, Norway. Extraction and clean up of the samples were conducted similar to Bernhoft and Skaare (1994) with modifications described in Borgå et al. (submitted to Chemosphere). (Extraction of lipids and organochlorines with cyclohexane and acetone, clean up with concentrated sulphuric acid to remove lipids. Separation of compounds on a high resolution gas chromatograph with electron capture detector (HRGC 5300 Mega Series, Carlo Erba). The compounds were identified by comparison with standards.) The samples were analysed for contents of -, - and -hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), cis-chlordane, trans-chlordane, oxychlordane and trans-nonachlor, the dichlorodiphenyltrichloroethane compounds p,p’-DDE, p,p’-DDD, and p,p’-DDT, and PCB congeners 28, 31, 47, 52, 66, 74, 99, 101, 105, 118, 138, 149, 151, 153, 170, 180, 187, 196. CYP P450 Enzymes Analysis: The seabird’s livers were analysed for the activity of testosterone hydroxylation and ethoxyresorufin-O-deethylation (EROD) as described by Wortelboer et al. (1990, Bopchemical Pharmacology, 40, 2525-2534) and Wolkers et al. (1996. Aquatic Toxicology, 35, 127-138). Stable Isotope Analysis: Parallel samples for analysis of stable isotopes were collected for stable isotopes. The analysis of stable isotopes was carried out at The Institute for Energy Technology, Kjeller, Norway.
The analytical quality of the Environmental Toxicology Laboratory at the National School of Veterinary Science was approved in international inter-calibration tests. The laboratory is accredited as a testing laboratory for the selected compounds according to requirements of NS-EN 45001 (1989) and ISO/IEC Guide 25 (1990), and the precision, linearity and sensitivity of the present analyses were within the laboratory's accredited requirements.
The Norwegian School of Veterinary Science, Oslo, Norway. The Norwegian School of Fishery Science, University of Tromsø, Norway. Akvaplan-NIVA A/S
The Norwegian Research Council's Ecotoxicology Programme. The Norwegian Ministry of Environment's Transport and Effect Programme