Heavy metal concentrations in three shorebird species from Okgu Mudflat, Gunsan, Korea

Iron, zinc, copper, lead, and cadmium were measured in livers of three shorebird species from Okgu Mudflat, Korea in the East Asian-Australian migration flyways. Iron concentrations in red-necked stints (Calidris ruficollis) (geomean = 1,322 mu g/g dw) were higher than in terek sandpipers (Xenus cinereus) (467 mu g/g dw), and great knots (Calidris tenuirostris) (158 mu g/g dw). Copper concentrations in great knots (85.8 mu g/g dw) were significantly higher than in red-necked stints (15.9 mu g/g dw) and terek sandpipers (10.4 mu g/g dw). However, significant differences in zinc concentrations were not found in livers among shorebird species. Iron, zinc, and copper concentrations from this study were within the range of other shorebird studies. We suggest that essential elements such as iron, zinc, and copper are within normal range and are maintained there by normal homeostatic mechanism. Lead and cadmium concentrations differed among shorebird species; red-necked stints (geomeans 27.8 mu g/g dw and 4.69 mu g/g dw, respectively) were higher than in terek sandpipers (12.9 and 0.44 mu g/g dw, respectively), and great knots (5.43 and 0.29 mu g/g dw, respectively). Some red-necked stints exceeded toxic levels of lead and cadmium for wild birds. In livers of red-necked stints from Okgu Mudflat, lead and cadmium concentrations were higher than previously reported in other shorebirds.