Occurrence of elevated nitrate in groundwaters of Krishna delta, India

Abstract

Nitrate concentrations were measured in the groundwater samples of Krishna delta, India. The results indicate a large variation of nitrate from 10 - 135 mg/l. In 79 groundwater samples, about 39% shows high nitrate contents (>50 mg/l), which is more than the permissible limits in drinking water. In north Krishna delta 49% and in south Krishna delta 26% water samples were found to exceed the permissible limits. This study indicates that groundwater of north Krishna delta is more polluted than south. Nitrate pollution level is found more in dug wells compared to hand pumps/bore wells. In this region 49% dug wells and 31% hand pumps have exceeded the desirable limits. The possible sources for the high nitrate level in groundwater were identified as excessive utilization of nitrogenous fertilizers for agricultural purposes.

Key words: Nitrate pollution, groundwater, Krishna delta, India.