Pratap B Singh and Vandana Singh
Keywords: Pesticide residues in fish; recoveries; testosterone; estradiol-17?; Heteropneustes fossilis.
Abstract: Effects of 40 days exposure and 20 days recovery response at sublethal concentration of technical grades of gamma isomer of hexachlorocyclohexane (?-HCH-0.025 ppm), dichlorodiphenyltrichloroethane (DDT-5.0 ppm) and chlorpyrifos (0.5 ppm) on the percentage rate of bioconcentrations in blood, brain, liver, muscles, ovary, gonadosomatic index (GSI) and plasma levels of testosterone and estradiol-17? were studied during prespawning phase in catfish, Heteropneustes fossilis (Bloch) during its annual breeding cycle. All pesticides caused maximum bioconcentration either in liver or ovary. Recoveries of these pesticides have also been recorded in aforesaid tissues except DDT in blood, brain, muscles and ovary when kept the fishes in pesticide free water. The percentage of bioconcentrations were maximum in all tissues but recoveries were maximum for blood (?-HCH), muscles (DDT) and liver (chlorpyrifos). The GSI, testosterone and estradiol-17? were decreased at all doses of pesticides. The exposed catfish kept in pesticide free water caused recoveries in GSI, testosterone and estradiol-17?. Our results indicate that pesticides have preferential order of percentage of bioconcentration in different tissues and have very selective effects on sex hormones thereby affecting reproductive physiology. Restoration of normal reproductive physiology during recovery phase might be due to dissipations of pesticides.
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