The influence of zinc on the uptake and loss of cadmium and lead in the woodlouse, Porcellio scaber (Isopoda, Oniscidea).

Uptake of cadmium, lead, and zinc was studied in juvenile Porcellio scaber in feeding experiments over 5 months. The metals were offered separately and in different combinations and concentrations in the food. The ability of P. scaber to eliminate the accumulated metals was studied subsequently for 3 months on uncontaminated food. Characteristic patterns of accumulation are described for the three metals. The combination of lead and zinc resulted in only minor differences in these patterns. On the other hand, the combination of zinc and cadmium at high concentrations completely changed the accumulation patterns for both metals. Not only cadmium but also zinc was excreted by P. scaber exclusively when the animals had been contaminated with both metals. In contrast both metals were stored permanently when offered separately. Possible reasons for the interactions of cadmium and zinc are discussed.