Relationship between endosulfan residue level and ultrastructural changes in the liver of catfish, Tandanus tandanus

Twenty four h after exposure to sublethal levels of endosulfan, all catfish contained residues of endosulfan in their livers, ranging from 1 to 82 μg kg-1 of total endosulfan. Structural changes such as presence of pyknotic nuclei, proliferation, dilation, and vesiculation of rough endoplasmic reticulum and presence of concentric membranous bodies were observed in the livers of cat fish containing endosulfan residues. The percentage of hepatocytes showing these changes was greater in the fish containing greater endosulfan residues. The percentage of pyknotic nuclei was greater in livers containing higher relative residues of beta endosulfan, as determined by the ratio of beta endosulfan residue to the sum of alpha endosulfan and endosulfan sulfate residues. Quantification of structural changes increases sensitivity of these changes as a potential biomarker of aquatic pollution.