BIOACCUMULATION OF ENDOSULFAN (THIODAN INSECTICIDE) IN THE TISSUES OF LOUISIANA CRAYFISH, PROCAMBARUS-CLARKII

The bioaccumulation potential of endosulfan was determined by constantly exposing male and female adult crayfish, Procambarus clarkiito 100 ppb ThiodanRinsecticide for 8 wks. The crayfish were removed at 2 wk intervals and the uptake by tissues (whole-body) was determined by electron capture gas-chromatography. The same number of pre-exposed crayfish (100 ppb ThiodanR) were transferred to endosulfan-free water after 8 wks, and insecticide loss (depuration) was similarly quan-titated. The maximum amount of insecticide and its metabolites detected after 8 wks were 197 ppb endosul-fan II 18 ppb endosulfan I and 3 ppb endosulfan sulfate. During the first 4 wks of depuration, endosulfan loss from crayfish tissues occurred rapidly, and only 3 ppb endosulfan I remained. No endosulfan II and sulfate were detected beyond 4 wks. The residues in male vs female were not significant statistically. Bioaccumulation factor (BF) for endosulfan II for crayfish tissues was 1.97, which is considerably lower than for other aquatic invertebrates (26 for scallop, Chlamys opercularisand 600 for mussel, Mytilus edulis.The presence of endosulfan sulfate in the tissues cannot be considered as ‘detoxification’ which is as toxic as the parent compound. © 1990, Taylor & Francis Group, LLC. All rights reserved.