Effect of pesticide toxicity in aquatic environments: A recent review

Abstract

Pesticides are widely used in modern agriculture to enhance the quantity and quality of yield in an effective and economical manner, leading to improved food security worldwide. Organochlorines, organophosphates, carbamates and pyrethroids are the four major groups of pesticides used. However, with increasing pesticide use, especially in developing countries, the risk of its toxicity caused by them is on the rise. Despite a low per hectare use of pesticides in India, their injudicious use has led to the presence of pesticide residues in both terrestrial and aquatic ecosystems. It has been observed that major riverine ecosystems like Ganges, Yamuna, Cauvery, Tapi and many others show the presence of pesticides in the water column as well as the river bed sediments. Pesticides tend to bioaccumulate in the food chain. Agricultural runoff into aquatic systems raises the risk of exposure of pesticides to non-target species, leading to adverse consequences on the ecosystem. In this review, an attempt has been made to critically review the usage of pesticides in India, their entry into riverine ecosystems and the impact of pesticides on freshwater microorganisms, invertebrates and vertebrates. The review of legislation in India to control pesticide usage shows that proper implementation of the laws is needed on an urgent basis.