Demarcating the Nitrate Polluted Ground Water Areas and Identifying the Contributing Factors in Fresh Water Zone of Haryana, India.

Over exploitation of ground water (GW) resources and increased use of chemical inputs in agriculture and industries has led to depletion and contamination in the GW resources in the State of Haryana in India. Increasing concentration of nitrate nitrogen (NO₃-N) in the ground water is one of emerging problems. Seven districts of the fresh water zone of Haryana were selected to demarcate the problematic regions in terms of NO₃-N in GW and to identify major causal factors. Water samples collected from 1772 locations were analyzed for NO₃-N using the copperized cadmium column reduction method and reagent kits. The inverse distance weighted interpolation method was applied for creation of grid maps. Spatial analyst tools of ArcGIS 9.2 software were used for multiple layers integration and spatial analysis. About 5% water samples had NO₃-N values above the critical limit of 10 ppm, whereas 8% samples were ranging between 7-10 ppm. NO₃-N concentration above 10 ppm may cause methemoglobinemia in infants. The areas under rice-wheat rotation were found with higher NO3-N values compared to wheat-sugarcane rotation. Higher concentration of NO₃-N was found in the regions with high ground water table. Soil texture, sub-surface water flow, topographic slope and features (e.g. pediments) had significant influence and control on spatial distribution of NO₃-N. Riverside areas had low nitrate concentration (2-4 ppm) whereas low lying areas (ponds) were found with higher nitrate concentration (8-22 ppm) levels. However, the influence of different factors on NO₃-N was location specific. Village-wise information on ground water NO₃-N for the seven districts should act as benchmark for future studies.