In search of biomonitors for cadmium: cadmium content of wild Swedish fauna during 1973-1976.

Forty-five species of birds and 22 species of mammals of the terrestrial and aquatic fauna, herbivores as well as carnivores, were investigated during the period 1973-1976 for cadmium-accumulating properties in order to find biomonitors for cadmium in the Swedish environment. The herbivores of the terrestrial fauna, birds as well as mammals, are preferred to carnivores, since they demonstrate generally higher renal Cd levels. The moose (Alces alces), roe deer (Capreolus capreolus) and hare (Lepus europeus and Lepus timidus) were found to be suitable as biomonitors because of their common occurrence and uniform geographical distribution. The eider duck (Somateria mollissima), although a short-distance migrating bird whose diet is composed mainly of mussels and crustaceans, and which lives along a great part of the Swedish coastline, is suggested as a biomonitor of cadmium for the aquatic environment. The accumulation rate of cadmium in the kidneys is rapid. Renal levels of cadmium in the parts per million range are reached 10 weeks after hatching. Juvenile birds should be collected for monitoring purposes before leaving their feeding domains at the end of the summer.