Groundwater is the main source of drinking water for many small agricultural communities. Nitrate concentration in groundwater is a major problem in Nira River basin area, which is mainly due to the run off or seepage of chemical fertilizers from the agricultural field. A total of 45 water samples were collected in the period of post-monsoon (POM) winter and pre-monsoon (PRM) summer seasons from bore wells. The water samples were analysed using standard methods of APHA suggested for analysis of nitrate. Groundwater quality parameter varies spatially in different seasons. In the present study, spatio-temporal variation in nitrate levels in bore wells of Baramati Tahsil area is examined. The results of analysis showed that nitrate concentration in POM and PRM was above the maximum permissible limit of WHO and BIS recommended for drinking purpose. In POM 74% groundwater samples from canal irrigated area and 11% from non-canal-irrigated area were above the standard limit of WHO and BIS. In PRM 66.67% and 11% samples respectively from canal irrigated and non-canal-irrigated area were above the maximum permissible limit of WHO and BIS (45 mg/l). This indicates that peoples especially children using the water from bore wells with higher concentration of nitrate than standard limit, stands a high risk of methemoglobinemia (sometimes referred to as “Blue baby syndrome”). In canal irrigated area concentration of nitrate was found higher than the non-canal-irrigated area. This may due to the use of more nitrogenous fertilizers by farmers in their farms, improper disposal of animal and human wastes in canal irrigated area as compared with non-canal-irrigated area. The groundwater of such bore wells was not suitable for drinking purpose without treatment at the time of analysis. Nitrate containing groundwater is more effective and useful for irrigation purpose. The nitrogen can be removed from drinking water by using treatment such as ion exchange, biological de-nitrification and reverse osmosis.
Prof. Dr. R. P. Dhok
Agricultural Development Trust’s Shardabai Pawar Mahila College, Savitribai Phule Pune University, Shardanagar, Baramati, India.