Nitrate pollution in groundwater in some rural areas of Nalgonda district, Andhra Pradesh, India.

Intake of water with high concentration of nitrate is a major problem in many countries as it affects health of humans. The present study was carried out with the objective of determining the causes for higher nitrate concentration in groundwater in parts of Nalgonda district, Andhra Pradesh, India. The study area is located at a distance of about 135 km towards ESE direction from Hyderabad. Nitrate concentration in groundwater of this area was analysed by collecting groundwater samples from 46 representative wells. Samples were collected once in two months from March 2008 to January 2009. The nitrate concentration was analysed in the laboratory using Metrohm 861 advanced compact ion chromatograph using appropriate standards. The highest concentration recorded during the sampling period was 879.65 mg/L and the lowest concentration was below detection limit. Taking into consideration 45 mg/L of nitrate as the maximum permissible limit for drinking water set by BIS, it was found that 13.78% of the groundwater samples collected from this study area possessed nitrate concentration beyond the limit. Overall, wells present in agricultural fields had nitrate levels within permissible limits when compared to those groundwater samples from wells present in settlements which are used for domestic purpose. This indicates that the high nitrate concentration in groundwater of this area is due to poor sanitation facilities and leaching from indiscriminate dumping of animal waste.