Assessing groundwater pollution potential from nitrogen fertilizers using geographic information system

Abstract

A U. S. Environmental Protection Agency, DRASTIC, was used to assess the vulnerability of groundwater from non-point source pollution in Ludhiana district of Punjab, India. Thematic maps of seven parameters of the model i. e. depth of water table, recharge, aquifer media, soil, topography, impact of vadose zone and hydraulic conductivity were prepared in a geographic information system (GIS) environment to obtain pollution potential indexes based on the hydo-geological parameters and consumption of nitrogenous fertilizers. The concentration of nitrate-N in groundwater of Ludhiana district was higher than the WHO prescribed limit (10 mg/l) but the concentration was less than the critical value (22.6 mg/l) which is responsible for causing the blue baby syndrome. There was an average rise of 2.77 mg/l in nitrate-N concentration in groundwater in Ludhiana district in last decade. The model was used to predict the future scenario and showed that with the present trend of consumption of nitrogenous fertilizers, in coming 10 years, all the area of the district may cross the WHO limit and approximately 8900 ha of area would even cross the critical limit. As per model prediction, the area under critical value may reach upto 50730 ha by the year 2012. Machiwara, Sidhwan bet and Ludhiana-2 blocks of the district will be severely affected.