Spatiotemporal Variation of Groundwater Quality in North Central Province, Sri Lanka

This study focused on fulfilling the demand for a comprehensive investigation of groundwater quality in the North Central Province (NCP) of Sri Lanka to achieve United Nations Sustainable Development Goal 6 (Ensure availability and sustainable management of water and sanitation for all). The NCP was selected as the study area due to its highest prevalence of chronic kidney disease with unknown etiology within Sri Lanka. Here, 334 shallow and deep groundwater samples were collected at the end of wet and dry seasons, respectively. Results revealed that elevated and unexpected levels of salinity, hardness, fluoride, nitrate, sulfate, and dissolved organic carbon and the alkaline nature of groundwater were the main issues, and the Ca-HCO3 type was dominant in the groundwater. Water quality index analyses showed that 8.9% and 13.8% of wells had poor quality undrinkable groundwater in wet and dry seasons, respectively. Only 7% of samples were susceptible to sodium and salinity hazards for irrigational use. Reverse osmosis technology with a softening and activated carbon pretreatment process was identified as the most suitable way to treat groundwater with high salinity for many regions of the NCP. The groundwater quality atlas for the NCP created by this study was very useful for making a master plan of safe drinking water supplies and developing and implementing cost-effective water purification technologies in the NCP