Environmental contaminants in Canadian shorebirds

Abstract

Canadian shorebirds are exposed to environmental contaminants throughout their annual cycle. Contaminant exposure among species varies with diet, foraging behaviour and migration patterns. We sampled twelve species of shorebirds from four locations across Canada to assess their exposure to PCBs, organochlorine pesticides, as well as four trace elements (Hg, Se, Cd, As). SigmaPCB and SigmaDDT followed by SigmaCHL were most frequently found above trace level in the shorebird carcasses. In general, the plover species (American golden, semipalmated, black-bellied) appear to be the most contaminated with organochlorines, whereas Hudsonian and marbled godwits appear to be the least contaminated. Among adult birds, the greater and lesser yellowlegs had the highest hepatic Hg concentrations (2.4-2.7 microg g(-1) dw), whereas American golden plovers as well as Hudsonian and marbled godwits contained relatively low levels of Hg (<1 microg g(-1) dw). Renal Se concentrations varied from 3.2 to 16.7 microg g(-1) dw and exhibited little interspecific or seasonal variation. Renal Cd levels in adult birds were highest in Hudsonian godwits from Quill Lakes (43 microg g(-1) dw) and Cape Churchill (12 microg g(-1) dw), and lowest (0.8-1.5 microg g(-1) dw) in greater and lesser yellowlegs from Cape Churchill and Bay of Fundy. Renal As concentrations varied from 0.06 microg g(-1) dw in golden plovers from Cape Churchill to 4.6 and 5.1 microg g(-1) dw in dunlin samples from the Pacific coast. There is no evidence that contaminants were adversely affecting the shorebirds sampled from the Canadian locations in this study.

Distribution of metals and trace elements in adult and juvenile penguins from the Antarctic Peninsula area

“…Seabirds from other regions of the world showed a wide range of As levels (from 0.22 to 5.62 μgg −1 d.w. in liver; Lucia et al 2010;Ribeiro et al 2009) which could be related to differences in their diets (Kubota et al 2001). In accordance with Braune and Noble (2009), As levels in our samples were lower than 3 μg g −1 d.w. (see Table 3), which are usual levels in living organisms.…”

Metals in tissues of migrant semipalmated sandpipers (Calidris pusilla) from Delaware Bay, New Jersey

“…The sample sizes in their study, however, ranged from 7 to 10. (Braune and Noble, 2009, dry weights) reported levels of mercury in liver of semipalmated sandpipers of 1.37 ppm in June in Churchill, and 1.23 ppm from Quill Lakes in August and 2.13 ppm in August/ September from the Bay of Fundy, supporting Didyk et al's suggestion of accumulating mercury while on migration. Hui et al (2001) reported levels in liver for several metals in western sandpipers (Calidris mauri) from San Francisco Bay: arsenic averaged 1.31-2.23 ppm (dry weight), cadmium averaged 1.06-1.23 ppm, chromium averaged 0.65 ppm, mercury averaged 4.43-4.17 ppm, and selenium averaged 12.2-13.4 ppm.…”

Geographic and Seasonal Variation in Mercury Exposure of the Declining Rusty Blackbird

“…Areas of Central and South America are of particular concern because mercury contamination is significantly increasing due to artisanal small-scale gold mining (UNEP 2013). Braune and Noble (2009) found liver mercury concentrations to be generally lower in 11 shorebird species sampled at noncontaminated sub-Arctic sites across Canada relative to those sampled in contaminated temperate wetlands . By contrast, however, Hargreaves et al (2010Hargreaves et al ( , 2011 found blood mercury concentrations in some shorebird species breeding in the eastern Canadian Arctic to be as high as those found in shorebirds sampled in mercury contaminated wetlands in San Francisco Bay.…”