MEPS 262:201-214 (2003)  -  doi:10.3354/meps262201

Influence of habitat, trophic ecology and lipids on, and spatial trends of, organochlorine contaminants in Arctic marine invertebrates

Aaron T. Fisk1,8,*, Paul F. Hoekstra1,2, Jean-Marc Gagnon3, Jason Duffe4, Ross J. Norstrom4, Keith A. Hobson5,6, Michael Kwan7, Derek C. G. Muir1,2

1National Water Research Institute, Environment Canada, Burlington, Ontario L7R 4A6, Canada
2Department of Environmental Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
3Canadian Museum of Nature, PO Box 3443 STN ŒD¹, Ottawa, Ontario K1P 6P4, Canada
4National Wildlife Research Centre, Environment Canada, Ottawa, Ontario K1A 0H3, Canada
5Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W0, Canada
6Prairie and Northern Wildlife Research Center, CWS, Saskatoon, Saskatchewan S7N 0X4, Canada
7Nunavik Research Center, Kuujjuaq, Quebec J0M 1C0, Canada
8Present address: Warnell School of Forest Resources, University of Georgia, Athens, Georgia 30602-2152, USA

ABSTRACT: Organochlorine contaminants (OCs) and stable isotopes of carbon (δ13C) and nitrogen (δ15N) were determined in 7 benthic and 7 pelagic marine invertebrate species from the North American Arctic to identify factors influencing OC concentrations. Values of δ13C separated benthic (enriched in 13C) from pelagic species and δ15N values gave a logical approximation of trophic level (TL). With few exceptions, OC concentrations in invertebrates were low (most were <5 ng g-1 wet wt) relative to the same or similar species in temperate waters and in the range expected for lower TL Arctic organisms. Polychlorinated biphenyls (PCBs) were the predominant OC group and lower chlorinated PCB congeners and hexachlorocyclohexane (HCH) isomers were the most common individual OCs in most species. Relatively higher levels of PCBs and high proportions of highly chlorinated PCB congeners were found in a small number of the pelecypod samples (Mytilus edulis and Mya truncata), suggesting that local harbors and communities can be point sources of PCBs in the Arctic. The OC concentrations (wet wt) varied by up to 2 orders of magnitude among species and were more variable among the benthic invertebrates. Lipid content, δ13C and δ15N were significant variables related to OC concentration, but differences among species remained after accounting for these variables. Scavenging, high TL, high lipid content and local point sources can all contribute to higher OC concentrations in Arctic marine invertebrates.

KEY WORDS: Stable isotopes · Carbon-13 · Nitrogen-15 · Zooplankton · Benthic · Pelagic

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