Chemical Contaminants in the Arctic Environment - Are They A Concern for Wildlife?

Abstract

—Environmental contaminants are a global problem, and their presence in the Arctic reflects the way in which the Arctic interacts with the rest of the world. Most contaminants are transported to the North on air and ocean currents from more southerly agricultural and industrial sources. Upon reaching the Arctic environment, many persistent contaminants bioaccumulate and biomagnify in the food web, making those species feeding at high trophic positions more vulnerable to contaminant exposure via their diet. By examining contaminant levels in wildlife, we can look for the arrival of new contaminants in the Arctic, as well as determine whether existing chemical contaminants of concern are increasing or decreasing. Historically, contaminants of concern included compounds such as the polychlorinated biphenyls (PCBs), and organochlorine pesticides such as dichlorodiphenyltrichloroethane (DDT). During the 1950s to 1970s, bioaccumulation of organochlorine compounds such as DDT and its degradation product, dichlorodiphenyl dichloroethane (DDE), were associated with eggshell thinning and reduced reproduction rates in top predatory species such as the Peregrine Falcon (Falco peregrinus). The majority of these legacy persistent organic pollutants (POPs) have significantly declined in Arctic biota over the last several decades. However, more recently, newer compounds such as brominated flame retardants (BFRs) and perfluorinated compounds (PFCs) have been detected in a wide variety of biota including Arctic wildlife. Certain metals are also contaminating the Arctic environment. Elemental mercury (Hg0) is highly volatile, and gaseous Hg partitions readily into the atmosphere where it can undergo long-range atmospheric transport to the polar regions which are global sinks for Hg. Although Hg occurs naturally in the environment, anthropogenic sources have been postulated to contribute more significantly to the occurrence of Hg in the Arctic than natural emissions, resulting in increasing Hg concentrations in a variety of Arctic biota, particularly in the Canadian Arctic and western Greenland. Recent warming ocean conditions and longer ice-free periods have also altered prey availability in some areas of the Arctic, affecting nutrition and chemical contaminant profiles. These changes in environmental conditions and contaminant exposure all contribute to the complexity of interpreting the contaminant profiles found in Arctic biota. Received 1 March 2011, accepted 19 April 2011. BRAUNE, B.M. 2011. Chemical contaminants in the Arctic environment–Are they a concern for wildlife? Pages 133–146 in R. T. Watson, T. J. Cade, M. Fuller, G. Hunt, and E. Potapov (Eds.). Gyrfalcons and Ptarmigan in a Changing World, Volume I. The Peregrine Fund, Boise, Idaho, USA. http://dx.doi.org/ 10.4080/ gpcw.2011.0114