Contaminants in the arctic marine environment: priorities for protection

Abstract

We assess evidence for significant adverse effects on the arctic marine environment associated with global and regional releases of chemical and radioactive contaminants from human activities. The sources, mode of transport, and biological effects of persistent organic compounds, lead, cadmium, mercury, artificial radionuclides, and oil are reviewed. An outline of the physical and biogeochemical processes occurring within the Arctic Ocean is used as a basis for identifying contaminant transport, accumulation, and exposure pathways. Where significant anthropogenic impacts can be inferred or suspected, we evaluate opportunities for human intervention through the introduction of new source controls, or other restrictions, to reduce impacts. We conclude that additional controls are justified only in the cases of persistent artificial organic compounds and petroleum exploitation and transport. Artificial radionuclides pose threats that are largely nominal. Protection of the arctic environment and human health can be achieved through universal compliance with existing international standards. Threats posed by cadmium and lead from anthropogenic sources are relatively minor. Trends in the anthropogenic mobilization of mercury are not currently defined with sufficient confidence to assess the associated dangers posed to animal and human health in the Arctic. Nevertheless, the properties of mercury and its current environmental levels suggest that the Arctic is sensitive to increased anthropogenic mobilization of this metal. There is also evidence that mercury levels in the Arctic are increasing due to anthropogenic activities. Accordingly, priority should be given to determining temporal trends of mercury within the Arctic.

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

“…[36] Seawater in the upper Arctic Ocean has residence times varying from one to 3 years on the shelves, ,10 years in the polar mixed layer, and ,30 years in halocline waters beneath the mixed layer. [39,40] Deeper in the ocean, the residence times are up to several centuries based on 14 C and other tracers. [41,42] Again, these ocean circulation rates set the time scale over which deposited Hg can be held in the various ocean reservoirs within the Arctic.…”

Concentrations and Interactions of Selected Essential and Non-Essential Elements in Ringed Seals and Polar Bears of Arctic Alaska

“…Cadmium and Hg occur at apparently elevated concentrations in marine mammals as compared to some domestic and laboratory animals. Consequently, they warrant investigation as potential risks to marine mammals or human consumers (Muir et al, 1992;Macdonald and Bewers, 1996). Some arctic species, especially marine mammals, may have evolved proficient physiologic mechanisms to detoxify and tolerate comparatively high concentrations of some potentially harmful metals (Dietz et al, 1998).…”

Concentrations and patterns of organochlorine contaminants in white whales (Delphinapterus leucas) from Svalbard, Norway

“…1996 . OC pollutants can also be transported to Arctic regions via ocean currents, river outflows, Ž continental run-off and ice-drift Ottar, 1981;Oehme, 1991;Barrie et al, 1992;Macdonald and . Bewers, 1996 .…”

“…Their low water solubility and high lipid solubility leads to their bioconcentration in lipid-rich tissues of organisms and their biomagnification between increasing trophic levels within ecosystems Ž . Thomann, 1989;Macdonald and Bewers, 1996 . OC concentrations are generally high in top Ž predators such as pinnipeds, polar bears Ursus .…”