Cadmium uptake by rainbow trout, <i>Salmo gairdneri</i> eggs and alevins

Abstract

The uptake of cadmium by eggs and alevins of rainbow trout from water concentrations of between 0.01 and 50.0 mg Cd 1 −1 was investigated. The cadmium content of eggs and alevins increased with time and with exposure concentration. Lower cadmium levels were detected in alevins than in eggs. Most of the cadmium (98%) in the eggs was found to be associated with the egg membrane or chorion. This explains the considerable reduction in cadmium concentration observed in alevins after hatching. Alevins hatching from eggs which had been exposed to cadmium survived longer in cadmium than alevins not exposed as eggs. This suggests that the pretreatment of eggs with cadmium serves some protective function. Behavioural and pathological signs of cadmium poisoning such as erratic swimming and blood clotting in alevins were observed.