A study of the absorption of 14C‐labelled DDT from water by fish

SUMMARY The distribution of DDT in brown trout poisoned by low aqueous concentrations of a labelled form of the insecticide has been studied. A direct‐mount technique for determining the carbon‐14 activity extracted from various organs is described. The DDT was rapidly removed from the water by the fish and by detritus, and relatively high concentrations were found in all organs and tissues examined. Storage occurs principally in the stomach, pyloric caeca, intestine, spleen, muscle and skin. The concentrations found in lipid extracts from the various organs generally showed much more uniformity than concentrations in terms of unit weight of tissue. It is suggested that the concentration of DDT present in the lipids may determine the toxicity to fish, thus explaining the greater susceptibility to DDT of fish in poor condition or of low fat content. DDT extracted from ovaries and testes indicates the possible danger to reproduction. The use of static water for fish toxicity tests involving insecticides is criticized.