Accelerated delivery of polychlorinated biphenyls (PCBs) in recent sediments near a large seabird colony in Arctic Canada
2009
Michelutti, Neal | Liu, Huijun | Smol, J. P. (John P) | Kimpe, Lynda E. | Keatley, Bronwyn E. | Mallory, Mark | Macdonald, Robie W. | Douglas, Marianne S.V. | Blais, Jules M.
Polychlorinated biphenyls (PCBs) were measured in sediment cores from ponds located near a large seabird colony at Cape Vera, Devon Island, Arctic Canada. Surface sediment PCB concentrations were approximately 5x greater in seabird-affected sites relative to a nearby control pond and were correlated with independent indicators of seabird activity including, sedimentary δ¹⁵N and lakewater chlorophyll a and cadmium concentrations. PCB fluxes were amongst the highest recorded from the High Arctic, ranging from 290 to 2400 ng m⁻² yr⁻¹. Despite a widespread ban of PCBs in the mid-1970s, PCB accumulation rates in our cores increased, with the highest values recorded in the most recent sediments. Possible mechanisms for the recent PCB increases include a vertical flux step driven by seabird-delivered nutrients and/or delayed loading of PCBs from the catchment into the ponds. The high PCB levels recorded in the seabird-affected sites suggest that seabird colonies are exposing coastal ecosystems to elevated levels of contaminants.
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