Persistence of Endosulfan in Selected Areas of Kasaragod District, Kerala

The persistence of organochlorine pesticides in different environmental matrices is a matter of concern as the complete environmental fate of these chemicals is still an unexplored field. Water, soil and sediment samples were collected from selected panchayats of Kasaragod district, Kerala in four different phases to assess the contamination by endosulfan applied on cashew plantations. Endosulfan was detected in only 2 samples out of 22 water samples analysed during the second phase of sampling. Concentration of endosulfan was below detection limit in all the 22 samples analysed during the third phase. A total of 14 sediment samples were analysed and during the third phase, the concentration of endosulfan was below detection limit in all the samples. Out of 13 soil samples, endosulfan was detected in 5 samples during the second phase and during the third phase it was detected in 3 samples. Endosulfan was detected in two soil samples from Panathadi and Muliyar Panchayats during the fourth phase. Also, comparison of results of the analysis of endosulfan during the third and fourth phase showed decrease in concentration in the three soil samples. The findings from the present study provide information on the current residue levels and persistence of organochlorine pesticide endosulfan in water, sediment and soil in selected areas of Kasaragod district. The study shows that combined toxic residues of endosulfan in the sediment and soil samples of selected areas of Kasaragod district were found to be persistent for a period of 1.5-2 years, but the persistence showed variations depending upon the climatic conditions and physico-chemical characteristics like pH, organic matter content and particle size of the soil in the area.