Ecology, Environment and Conservation Paper

CHLORPYRIFOS INDUCED ACUTE TOXICITY AND BEHAVIOURAL RESPONSES IN JUVENILE COMMON CARPS (CYPRINUS CARPIO VAR. COMMUNIS) OF KASHMIR

Imtiyaz Qayoom, Masood H. Balkhi, Malik Mukhtar, Feroz A. Shah and Bilal A. Bhat

Abstract

A 96-h LC50 value of chlorpyrifos, an important agricultural insecticide used in the orchards and croplands of Kashmir valley was determined on fingerlings of Cyprinus carpio var. communis. Experimental animals weighing 10±2 g were selected for bioassay and the mortality data was statistically evaluated by Finney’s Probit Analysis Method. The 96-h LC50 value for Cyprinus carpio var. communis was found 3.8 ppb in a static bioassay test system. The mean values of water quality in aquarium depicted a slight variation indicating that the mortality of aquarium fishes occurred due to pesticide exposure and not suffocation. Lab. Temperature recorded was 9.0 ±0.0 oC; water temperature 7.0 ±0.0 oC; dissolved oxygen 4.36±0.40 - 4.64 ±0.64 mg/L; pH 6.92±0.13-7.04±0.54; total dissolved solids 3.33±1.33×103 -mg/L were recorded while as the CO2 remained at a constant value of 2.0±0.0 mg/L. The carp fingerlings exhibited gradual behavioural responses such as uncoordinated movements, convulsions, excessive mucus secretion, imbalanced swimming with spiral and erratic movements which ended in a collapse to the bottom of the aquarium and increase in respiratory motions during the entire period of experiment. Prior to death, the clinical signs like erosion of scales, turning of body colour into pale and hemorrhagic patches all over the body were well noticed which became more vivid upto the termination of the experiments. The results indicated the potential toxicity of the pesticide to fishes which, if present in the natural waterbodies, could be hazardous not only to fishes, but to humans as well through the entire food chain.