Organochlorine and Organophosphorous pesticides residues in Water of River Ganga at Bhagalpur, Bihar, India

Abstract

River Ganga along with its tributaries is the largest and also a very important river basin of India. The river Ganga, a holy river has over the years been subjected to tremendous pressure due to discharge of untreated sewage, industrial effluents, residues of pesticides and insecticides used in farms which has adversely affected the ecological health of the river and its basin The objective of this study was to identify and quantify some selected pesticides both organochlorine and organophosphorous present in water of River Ganga at Bhagalpur. These pesticides are mainly used to control the soil and crop pests in agricultural fields and direct dumping of wastes in to river systems. Combination of their physico-chemical properties such as low aqueous solubility, moderate vapor pressure and octanol – water partition coefficient and persistence in the environment make them capable of long-range transport. Water samples from 3 sites (up stream, mid stream and down stream) were collected and analyzed for their pesticide profile. The study has shown the presence of both organochlorine and organophosphorous pesticides in the water of River Ganga at Bhagalpur. Liquid-liquid extractions followed by GC-ECD were used for the determination of these compounds. Among the various pesticides analyzed, high concentration of Methyl parathion, Endosulfan and DDT were observed in water samples collected from the River Ganga at Bhagalpur. Especially, the concentration of DDT was quite high which might be due to slow degradation of DDT in soil i.e. 75 –100% in 4-30 years. The present study was first attempt to identify and quantify some selected pesticides in water and sediment of the river Ganga at Bhagalpur, and may be important as the Bhagalpur city gets its water supply from the river for drinking purposes.