Biotransport of organic contaminants and mercury to a coastal food web in the Canadian High Arctic

Abstract

Seabird-derived nutrients enhance plant abundance in coastal ecosystems, increasing rates of primary productivity, and indirectly increasing consumer populations. However, at Cape Vera, concentrations of contaminants in the sediment of ponds below nesting colonies of northern fulmars (Fulmarus glacialis) are 10 to 60 times higher than in reference ponds (Blais et al. 2005). This pattern suggests that the colony concentrates hexachlorobenzene (HCB), total mercury (THg), and dichlorodiphenyltrichloroethane (DDT) through guano to pond sediments (Blais et al. 2005). It remains unclear whether the effects of these contaminants are localized to the ponds or whether they enter the food chain. This study was designed to determine whether organochlorines and mercury were transferred from a seabird colony to coastal food webs. Contaminant concentrations were measured in primary producers and animals. Nitrogen stable isotopes were used to detect seabird influence. Concentrations of SigmaPCB and SigmaDDT in organisms were high relative to other Arctic areas; however, THg concentrations were similar. Snow buntings (Plectrophenax nivalis ) had SigmaPCB (mean: 168 ng/g ww) and SigmaDDT (mean: 106 ng/g ww) concentrations that surpassed environmental guidelines for protecting wildlife. Biovector transport may be a source of contaminants to certain organisms at Cape Vera.