Inter-state Mobility of Pesticide Leachate in Underground Water

Pesticide usage has become an integral part of modern agriculture; excessive and injudicious usage of which generally leads to groundwater pollution. Assessment of pesticide impact on groundwater, employing certain tools and available dataset, is a foremost step towards the preparation of regulatory policies that governs the application of pesticides to agricultural fields. In this study, the impact of pesticide usage is assessed for an agricultural area lying in North-western India employing a model named Pesticide Impact Rating Index (PIRI). Four pesticides wiz. Atrazine, Chlorophyrifos, Phorate and Monocrotophos, were selected and a relationship is established between their usage and their impact on the quality of groundwater (by employing PIRI) for the study area consisting of seven farms lying in Nakodar tehsil of Punjab state in India. Groundwater sampling was conducted for these locations and samples were analyzed for observed values of pesticide residues. Furthermore, these observed values were compared with the PIRI model estimates and results showed that though the observed values were higher corresponding to the estimated values, but the ratio seemed to be fluctuating within consistent range. Therefore, the evaluation of PIRI model for the study area resulted in promising results subject to the introduction of multiplicative correction factors for the model estimates so as to predict realistic pesticide residues in the area corresponding to local conditions and considered time frame of analysis. The study is further extended to observe the occurrence of the pesticides in the downstream side of the study area. The same pesticides have been detected in underground water available in desert of Jaisalmer district of Rajasthan which is about 700 km away from the area where these pesticides are used. It indicates inter-state pollution and contamination of underground water, the remediation of which is of utmost importance for the study area and is recommended for a sustainable future.