Nitrate contamination found in groundwater across 502 districts: CentreGroundwater nitrate contamination above the permissible limit has been detected in parts of 502 districts across 26 states and UTs, with 20.71 per cent of tested samples exceeding limits, the government told Parliament. “Nitrate contamination above the permissible limit has been observed in parts of 502 districts across 26 states/UTs,” the minister said. Karnataka has 27 partially-affected districts, including Davanagere, due to nitrate contamination, the reply stated. The Karnataka government similarly said it had not conducted any exclusive study on nitrate contamination or the environmental fallout of excessive fertiliser use in the state. “Excess nitrogen is primarily lost through nitrate leaching, resulting in groundwater nitrate contamination, with nitrate concentrations exceeding the permissible limit of 10 mg/L in some areas,” the minister said, adding that groundwater nitrate levels were found to rise in tandem with fertiliser application rates, with higher contamination recorded in areas of intensive fertiliser use.