Vol. 2, Issue 5, Part P (2016)

Abstract
Pesticides are widely used in modern agriculture to aid in the production of high quality food. However, some pesticides have the potential to cause serious health or environmental damage. Repeated exposure to sub-lethal doses of some pesticides can cause physiological and behavioural changes in fish that reduce populations, by causing abandonment of nests and broods, decreased immunity to disease and increased failure to avoid predators. Monocrotophos is one of the organophosphorus pesticide used in this study. The median lethal concentration (LC50) of MC to fish L. rohita for 96 hour was found to be 45.1 ppm. In sublethal concentration (1/10th of LC50 96 hour value, 4.51ppm) fishes were exposed for 24, 48, 72 and 96 hrs, 10 days, 20 days and 30 days. Organs of fishes were sacrificed and tested for enzymatical analysis. A significant decrease in ACP, ALP values and maximum increase in GOT, GPT and LDH values were observed throughout the study period when compared to the controls. It is essential for assessing the ecological risk of these pesticides.