BIOTOXICITY POTENTIAL OF ORGANOPHOSPHATE IN COMMON CARP (CYPRINUS CARPIO)

Abstract

Dichlorvos, an organophosphate pesticide, is extensively used for agricultural purposes. Contamination of water by dichlorvos as a consequence of agricultural runoff has been reported in reports. The objectives of the current study were to determine the toxicity and bioaccumulation potential of dichlorvos in Common Carp (Cyprinus carpio). The effect was determined on the basis of acute and sub-acute toxicity test results. A semi static toxicity bioassay was performed according to standard method and LD50 values determined for 24, 48, 72 and 96 h exposure were recorded to be 34.27, 28.61, 26.12 and 22.51 mg L-1. Sub-acute toxicity test was performed by exposing organism with sub-lethal concentrations (1.3, 1.8 and 2.34 mg L-1) of dichlorvos for 14 days. RBC, WBC, Hb and plasma protein showed significant decrease in levels but plasma glucose increased as the exposure dose was increased. Hepatosomatic index and gonadosomatic index showed decline trend indicating profound effect on liver and gonads of fish. Plasma content of males was analysed to find vitellogenin induction potential of dichlorvos. Male fish were exposed with sub-lethal doses in order to determine vtg concentration. The results showed that dichlorvos has a tendency to feminize the male fish. Bio-accumulation of dichlorvos was observed in muscle tissues through GC-ECD. The results showed 50, 70 and 75 % accumulation of dichlorvos residues when exposed with sub-lethal doses of 1.3, 1.8 and 2.34 mgL-1 for a period of 45 days.