Responses of biotransformation and antioxidant enzymes in Lemna minor and Oncorhynchus mykiss exposed simultaneously to hexachlorobenzene

Effect of hexachlorobenzene (HCB), a persistent environmental contaminant, exposure on the enzymes of oxidative biotransformation and antioxidant system of the aquatic plant L. minor and fish were studied simultaneously. Furthermore, the effects of fish - plant interactions in a HCB polluted environment on the responses of hepatic biotransformation and antioxidant enzymes of fish were also investigated. The peroxidase and glutathione S-transfemse (GST) activity in HCB exposed plants were significantly high following 1, 2 and 7 days of the exposure. In general, the activity of antioxidant enzymes in plants also increased following exposure to HCB. Exposure to either HCB or plants in uncontaminated water did not cause any major changes in the hepatic microsomal monooxygenase and antioxidant enzyme activities in fish. However, significant inhibition in liver monooxygenase enzyme activities and increase in the antioxidant enzyme activities were observed in fish that were exposed to HCB in the presence of L. minor. Such observations suggests that interactions between fish and plants in a HCB contaminated environment may affect fish hepatic biotransformation and antioxidants enzymes.