Metal levels in livers of waterfowl from Korea

This study presents concentrations of heavy metals (iron, zinc, manganese, copper, lead and cadmium) in livers of white-fronted geese (Anser albifrons), eurasian wigeons (Anas penelope), mallards (Anas platyrhynchos) and spot-billed ducks (Anas poecilorhyncha) from Korea in February 2006 and 2008. Iron concentrations were significantly lower in spot-billed ducks than in other species (ANOVA, p<0.001). Zinc concentrations were greater in white-fronted geese and spot-billed ducks than in eurasian wigeons and mallards (ANOVA, p<0.001). Manganese and copper concentrations in white-fronted geese were significantly higher than in other species (ANOVA, p<0.001). Cadmium concentrations were significantly higher in mallards and spot-billed ducks than in white-fronted geese (ANOVA, p=0.007). However, lead concentrations did not differ among species. Iron, zinc, manganese and copper concentrations from this study were within the range of other waterfowl studies. Therefore, we suggest that essential elements such as iron, zinc, manganese and copper are within normal range and are maintained there by normal homeostatic mechanism. Twenty individuals (29.0 percent) exceeded the threshold level for abnormal lead exposure (5 μg/g dry weight) in waterfowl in this study and it is a higher proportion than in herons, egrets and owls from Korea. We suggest that the result was attributed to ingestion of lead shot and sinkers. However, cadmium concentrations in waterfowl except one specimen were within the background concentrations for wild birds. In livers of four waterfowl species found in Korea, lead and cadmium concentrations were similar to previously reported in other geese and ducks; except for poisoning of lead shot or sinkers as shown in earlier studies.