Ecotoxicology of copper and cadmium in a contaminated grassland ecosystem. III. Small mammals.
Detailed dietary analysis throughout the year established seasonal changes in the diet selected by Microtus agrestis, Apodemus sylvaticus and Sotex araneus in contaminated and control grasslands. Metal contamination levels in small mammal diets followed the order S. araneus > M. agrestis > A. sylvaticus and varied substantially throughout the year. newline˜At relatively low levels of cadmium exposure M. agrestis and A. sylvaticus appeared to regulate cadmium accumulation. In contrast, S. araneus showed considerable accumulation of cadmium. Total body:diet concentration factors were greater than one at control and refinery sites. The highly contaminated nature of the invertebrate diet of S. araneus resulted in ingestion of three times more copper and twelve times more cadmium than for M. Agrestis occupying the same contaminated grasslands. newline˜Cadmium was highly mobile in the soil-plant-invertebrate-small mammal system. In contrast, copper was mobile through the soil-plant-invertebrate pathway but accumulation was effectively regulated in small mammals at all levels of dietary intake.