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

摘要

Organochlorine contaminants (OCs) and stable isotopes of carbon (δ~(13)C) and nitrogen (δ~(15)N) were determined in 7 benthic and 7 pelagic marine invertebrate species from the North American Arctic to identify factors influencing OC concentrations. Values of δ~(13)C separated benthic (enriched in ~(13)C) from pelagic species and δ~(15)N 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, δ~(13)C and δ~(15)N 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.