UPTAKE AND TISSUE DISTRIBUTION OF DIETARY AND AQUEOUS CADMIUM BY CARP(CYPRINUS-CARPIO)

The aim of this study was to assess whether contaminated prey can be a major source of Cd for fish, For this purpose, the uptake and tissue distribution of dietary and aqueous cadmium by the carp (Cyprinus carp io) was studied, The fish were exposed to either Cd-contaminated food or Cd-contaminated water for 4 weeks in laboratory experiments, When e xposed to contaminated food, the fish were kept in clean water and fed contaminated chironomid larvae, equilibrated with 99 mu g Cd . liter( -1). During exposure to contaminated water (nominal 100 mu g Cd . lite r(-1) actual 80 mu g Cd . liter(-1)) the fish were fed uncontaminated food. The Cd accumulation in the tissues of fish fed contaminated larv ae was, in decreasing order, gut > kidney > liver = gill > muscle, In the water experiment this order was gut > gill > kidney > liver > musc le. In almost all tissues the Cd uptake was similar for both routes; o nly the gill had accumulated more Cd from Cd-contaminated water than f rom Cd-contaminated food. Considering the ongoing discussion of the im portance of Cd transfer from contaminated food to predators, these fin dings suggest that uptake of Cd from Cd-contaminated prey by fish play s an important role in contaminated waters. (C) 1995 Academic Press, I nc.