Nitrate contamination of groundwater: An issue for livelihood in Jaffna Peninsula, Sri Lanka

Abstract

Groundwater stored in large cavities and channels of Miocene limestone is the only source of portable water in Jaffna Peninsula, Sri Lanka. It is increasingly exploited and polluted by various contaminants that results in less availability of potable water. Nitrate contamination in drinking water is one of the major concerns which causes severe health impacts, such as methemoglobinemia especially in infants and oesophageal and stomach cancers. The current nitrate levels in drinking water in Jaffna peninsula are much higher than the WHO and SLS levels. The nitrate-N content of groundwater in the Jaffna Peninsula ranges from 0.1 to 45 mg/L as per the literature though the permissible nitrate-N level in drinking water is 10 mg/L. Further, the nitrate concentration in groundwater varies seasonally and is found to be higher during the wet season than the dry season. Research studies carried out at different localities in the Peninsula from 1983 to 2018 have shown that nitrate content of groundwater has increased over this period. A recent investigation in the Chunnakam area revealed nitrate-N level of 45 ppm. Hence, nitrate contamination of groundwater in the Jaffna Peninsula is found to be the most challenging issue in the water management system.