Ecotoxicology of copper and cadmium in a contaminated grassland ecosystem. IV. Tissue distribution and age accumulation in small mammals.
Tissue distribution and accumulation of Cu and Cd are described for populations of Apodemus sylvaticus, Microtus agrestis and Sorex araneus populations inhabiting control and refinery-site grasslands. Despite high ingestion rates for Cu at the Cu-refinery sites, accumulation appeared to be effectively regulated by in-built homeostatic mechanisms. At low levels of Cd intake, accumulation was centred on the kidney and liver. However, at the high daily ingestion rates of 25 µg/g recorded for S. araneus, storage of Cd in the liver increased compared with storage in the kidney. In the refinery population of S. araneus, liver Cd concn were 2 to 3 times greater than kidney concn; this represents storage of 87% and 6% of the total body burden of Cd in the liver and kidney, respectively. Cd concn of 800-1120 µg/g in the liver and 400-500 µg/g in the kidney are among the highest recorded in terrestrial wildlife. Cd accumulation was positively correlated with age in S. araneus.