Histopathological Effects of 2,2-Dichlorovinyl Dimethyl Phosphate (DDVP) on Coptodon Zillii (GERVAIS, 1848) Juveniles

Abstract

Abstract

Concerns have often been raised on the application of pesticides on croplands and the threats posed on aquatic organisms. These pesticides get to the aquatic system from runoff on croplands where there was excessive application This study was designed to investigate the lethal concentration of an agricultural pesticide; 2,2-Dichlorovinyl Dimethyl Phosphate (DDVP) on the physical and chemical properties of water as well as the liver, kidney and gills of Coptodon zillii juveniles. A total of 150 experimental fish (average length 6.2±0.32cm and weight 0.9±0.11g) were stocked in culture tanks (43cm x 30cm) of 10litres water capacity at the rate of 1fish/L. The bioassay media concentrations were 0mg/l (A), 0.33mg/l (B), 0.67mg/l (C), 1.0mg/l 6 6 5 (D) and 1.3mg/litre (E) and representing 0mg/l, 3.3 x 10- mg/l, 6.7 x 10- mg/l, 1.0 x 10- mg/l and 5 1.3 x 10- mg/l of active ingredient Dichlorvos DDVP (1000g/L) EC respectively in three replicates of a Completely Randomized Design (CRD) experimental setup. Temperature, pH, Dissolved Oxygen (DO) and Chemical Oxygen Demand (COD) were measured before and after inclusion of the pesticide. Significant differences (P<0.05) were observed in mean concentration of DO and COD. The experimental fish exhibited restlessness and uncoordinated movement. These behavioural characteristics increased with increased concentration of DDVP and time of exposure. The LC for C. zilli juveniles after 96hours exposure was 0.39mg/l. Histological 50 photomicrograph showed areas of lesions, necrosis, inflammatory bodies and malignancy in the gills, liver, kidney and muscle of the exposed experimental fish while the control was normal. The result indicated that DDVP is highly toxic to C. zilli and must be applied at recommended dosages for sustainability of the living communities and the general ecosystem.