Assessing groundwater quality using the Water Quality Index (WQI) and GIS in the Uva Province, Sri Lanka

The prime objective of this study is to develop a water quality index (WQI) to identify the relationship between the drinking water quality and the prevalence of Chronic Kidney Disease of Uncertain Etiology (CKDu) in the Uva Province (UP). For this, all CKDu patients in the province were recorded. 251 groundwater samples were collected and analyzed for their major cations and anions. Following this procedure, the spatial distribution maps for CKDu patients, water quality parameters and WQI were generated. The results revealed that, 20.3% of groundwater samples are categorized under “excellent” in terms of the drinking water quality, 21.2% of the samples are categorized under “good”, 20.3% of the samples are categorized under “poor”, 9.9% of the samples are categorized under “very poor”, and 28.3% of the samples are categorized under “unsuitable” in terms of the WQI. According to the results, the most significant correlation was recorded between fluoride content in the samples and WQI (0.96). Statistical analysis showed that the WQI has a strong positive correlation (0.68) with the spatial distribution of CKDu patients in the UP inferring that groundwater quality has a significant effect on the prevalence of CKDu in the UP. Moreover, these maps can be effectively used by decision makers for groundwater quality management activities in the UP, Sri Lanka.