Why Do Organochlorine Differences between Arctic Regions Vary among Trophic Levels?

Abstract

Statistical analysis of organochlorine contaminants (OCs) in marine mammals has shown that, for most OCs, the European Arctic is more contaminated than the Canadian and U.S. Arctic. Recently, comparison of OC concentration ranges in seabirds, arctic cod (Boregadus saida), and zooplankton, found no difference between these regions. To address these inconsistencies, marine food web OC data from the European (central Barents Sea (CBS)) and Canadian Arctic (Northwater Polynya (NOW)) were simultaneously statistically analyzed. In general, concentra tions of OCs were greater in seabirds and ringed seals (Phoca hispida) from the CBS as compared to the NOW; consistent with circumpolar trends observed in marine mammals. In contrast, levels of OCs were generally similar in zooplankton and arctic cod between the CBS and NOW. The main exception is HCH which had greater levels in the NOW across all trophic levels because of the greater proximity to sources in eastern Asia. The lack of differences in OC concentrations in zooplankton and Arctic cod from the European and Canadian Arctic suggest that regional differences in OC contamination in the Arctic have evened out. Reduced regional differences were not observed in marine mammals or seabirds because they are long-lived and also acquire contaminants from maternal transfer and hence reflect levels from the past when the European Arctic was more contaminated than the Canadian Arctic. In addition, seabirds may reflect exposure from other areas. This study highlights the potential problem of comparing spatial trends by using means and confidence intervals as compared to simultaneous statistical analysis of raw data. Differences in the spatial trends of OCs between trophic levels in the Arctic are important for consideration when assessing regional differences in spatial and temporal trends of discontinued and current-use contaminants.

Persistent organic pollutants in four bivalve species from Svalbard waters

“…In Kongsfjorden, the contribution of local point sources on PCB concentration in macrobenthos has been shown to be minimal or non-existent (Hop et al, 2001). The findings of similar P CHLOR levels in amphipods from the European and North American Arctic (Borgå et al, 2005), however, are contradictive to the spatial pattern found between the study of Fisk et al (2003) and our results. The trend of lower P CHLOR levels in bivalves from the European than the North American Arctic (Fisk et al, 2003) has been confirmed by other studies done in Svalbard (Angot, 2009;Tessmann, 2008).…”

“…This percentage is estimated based on the PCB pattern observed before in M. truncata from Svalbard (Hop et al, 2001). A recent comparison of circumpolar OC data also showed higher P PCB in amphipods from the North American compared to the European Arctic (Borgå et al, 2005). Fisk et al (2003) suggested that elevated PCB levels might be due to local input from point sources in the North American Arctic.…”

Chiral Organochlorine Contaminants in Blood and Eggs of Glaucous Gulls (Larus hyperboreus) from the Norwegian Arctic

“…Therefore, in order for similar steady-state EFs to occur between these two populations, the birds must have a regular consumption of prey containing analogous enantiomer distributions of chiral compounds. It has been shown that glaucous gulls from Svalbard and the NOW polynya in the Canadian Arctic feed at similar trophic levels , although their opportunistic diets may include a wide variety of food items that may differ between these two populations. In general, the few studies investigating EFs in lower trophic level organisms from both Svalbard and the NOW polynya found that they contained EFs of most OC compounds which were closer to racemic than EFs measured in glaucous gulls from these arctic locations ,− .…”

The influence of global climate change on accumulation and toxicity of persistent organic pollutants and chemicals of emerging concern in Arctic food webs

“…Environmental changes in contaminant exposure appear to be reflected faster in zooplankton than in longer-lived, higher trophic-level organisms. 92 Thus, extrapolating the results of this study to approximate future climate change effects should be done with caution. Space-for-time approaches require two contrasting sites that are comparable with regards to other potential confounding factors within- or between-sites.…”