Accelerated delivery of polychlorinated biphenyls (PCBs) in recent sediments near a large seabird colony in Arctic Canada Neal Michelutti a, * , Huijun Liu b , John P. Smol a , Lynda E. Kimpe c , Bronwyn E. Keatley a , Mark Mallory d , Robie W. Macdonald e , Marianne S.V. Douglas f , Jules M. Blais c a Paleoecological Environmental Assessment and Research Laboratory (PEARL), Department of Biology, Queen’s University,116 Barrie St., Kingston, ON K7L 3N6, Canada b Department of Environmental Science, Zhejiang Gongshang University, Hangzhou, China c Program for Chemical and Environmental Toxicology, Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada d Environment Canada, Iqaluit, NU, Canada e Department of Fisheries and Oceans, Sidney, BC V8L 4B2, Canada f University of Alberta, Edmonton, AB T6G 2E3, Canada Seabird activity accelerates the delivery of PCBs from marine to terrestrial ecosystems. article info Article history: Received 20 January 2009 Received in revised form 23 March 2009 Accepted 21 April 2009 Keywords: Polychlorinated biphenyls Biovector transport Seabirds Paleolimnology Arctic Canada abstract 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 w5 greater in seabird-affected sites relative to a nearby control pond and were correlated with independent indicators of seabird activity including, sedimentary d 15 N 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 nutri- ents 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. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Industrial pollutants pose a serious threat to Arctic ecosystems. Chemicals such as polychlorinated biphenyls (PCBs), organochlo- rine pesticides and mercury continue to exceed health safety guidelines in some of the traditional foods of indigenous peoples, including certain fish, marine mammals and seabirds (INAC, 2003). In addition to these ‘‘legacy pollutants’’ that have been known for some time, emerging pollutants such as brominated flame retar- dants and perfluorinated acids are increasing in the Arctic with doubling times of six to eight years (Ikonomou et al., 2002; Martin et al., 2004; Young et al., 2007). Government regulators and managers require a more thorough understanding of contaminant pathways to Arctic food webs if they wish to effectively mitigate these problems. An often overlooked contaminant pathway is biological trans- port. Recent evidence has shown that migratory animals can concentrate chemicals to potentially toxic levels in specific receptor sites (reviewed in Blais et al., 2007). Typically, these receptor sites are diverse and productive ecosystems because biovectors usually also deposit nutrients via wastes and mortality. For example, anadro- mous fish such as sockeye salmon in Alaska (USA) and British Columbia (Canada) are known to provide critical nutrient subsidies to some inland ecosystems, but have also been shown to concentrate persistent organic pollutants (POPs) in the sediments (Kru ¨ mmel et al., 2003, 2005) and food webs (Ewald et al., 1998; Gregory-Eaves et al., 2007) of their natal lakes where they die after spawning. The most globally relevant biovectors are probably seabirds, which are found on every continent and have populations reaching tens of millions of individuals in the Canadian Arctic alone (Mallory and Fontaine, 2004). Many seabird species occupy high trophic positions in the marine food web and, as a result, often accumulate elevated levels of contaminants due to biomagnification (Fisk et al., 2003). When seabirds congregate on shore, often in dense nesting colonies, they funnel a portion of their bioaccumulated contami- nants to the land via guano and mortality. Indeed, seabirds in Arctic regions have been observed to concentrate considerable amounts * Corresponding author. Tel.: þ1 613 533 6159; fax: þ1 613 533 6617. E-mail address: nm37@queensu.ca (N. Michelutti). Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol 0269-7491/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.envpol.2009.04.025 Environmental Pollution 157 (2009) 2769–2775