Bioaccumulation and Tissue Partitioning of Endosulfan by the Red Hybrid <i>Tilapia</i>

Abstract

The frequent use of endosulfan in agricultural activity on steep slopes in Jamaica and subsequent contamination of rivers by the residues resulted in a need to assess the levels of bioaccumulation of sub-lethal doses of the insecticide in river fauna using Tilapia fish as a test subject. Bioconcentration of α-and β-endosulfan by the Red Hybrid Tilapia, from 0.0075 mg L −1 in the surrounding water, reached a peak (0.578 ppb and 0.442 ppb, respectively) in one to four hours but fluctuated during the rest of the 72h observation period. A similar pattern of bioaccumulation was recorded when the fish were exposed to 0.015 mg L −1 , except that the peak bioaccumulation of α-and β-isomers after one hour of exposure were 0.54 and 0.44 mg L −1 , respectively. The contaminated fish (from 24-h exposure to 0.015 mg L −1) eliminated only 18 to 31% of endosulfan residues after 24 h and 26 to 39% after 72-h exposure to uncontaminated water. During the process of bioconcentration, endosulfan was metabolized to endosulfan lactone and sulfate; the degradation was more during the elimination process when exposed to clean water. Maximum amounts of α-and β-endosulfan and their metabolites were partitioned in gonads > liver > gills > skin/muscle/bone.