ABSTRACT
Contaminant transport modeling was performed with MODFLOW and MT3D models to investigate the increase in the mean nitrate concentration of shallow groundwater in Ludhiana district, India. The concentration was found to be directly related to the increased use of nitrogenous fertilizers. It was revealed that the nitrate nitrogen concentration was above WHO’s recommended limit for drinking water in 68 per cent of the area in pre monsoon and in 84 per cent of the area in post monsoon periods. The increase in the nitrate nitrogen concentration in groundwater was found to be more in south eastern blocks of the district compared to western blocks due to higher usage of nitrogenous fertilizers in the former. Contaminant transport model was observed to be most stable with upstream finite difference numerical method.
