Abstract
Chronic Kidney Disease of unknown etiology (CKDu) ranked as one of the most attended public health issues in Sri Lanka. The etiology of the disease is believed to be environmentally induced as it appears in geographically discreet regions of the dry zone of Sri Lanka. Girandurukotte and Wilgamuwa are two regions where CKDu is more prevalent. This study performs a comparative analysis to separately identify the quantitative differences of hydrogeochemical parameters of groundwater samples consumed by the patients and non-patients in two regions. Besides, groundwater quality data of 421 wells from Girandurukotte and Wilgamuwa were used for the analysis. Out of 421 samples, 310 samples were collected from wells where patients were reported. Descriptive statistics, Correlation analysis and Factor analysis were performed. Results of comparative analysis conclude that means of iron (Fe) content in Wilgamuwa CKDu (371 μg/L) and non-CKDu (731μg/L) exceeds the WHO permissible limits. The mean ion content of F-, Cl-, NO3-, SO42- and Na+ in the water wells consumed by the CKDu patients in the Wilgamuwa region is higher in concentration than non-CKDu wells. Out of major elements, Mg2+, Ca2+, K+, Na+, NO3- and hardness contents are higher in Wilgamuwa CKDu wells compared to the Girandurukotte CKDu wells. Trace elements such as As, Cd, and Pb do not exceed the WHO recommended limits in both regions. Generally, except for Fe ion concentration, almost all the other ion concentrations are within the WHO recommended limits. Correlation analysis reveals that Total Dissolved Solids (TDS) is highly positively correlated with alkaline earth metals Mg2+ (0.93), Ca2+(0.86) and Sr2+(0.85) in Wilgamuwa CKDu water sources. Also, Electrical Conductivity (EC) is highly positively correlated with Ca2+(0.84), Ni (0.82) and Sr (0.81) in Wilgamuwa non-CKDu water sources. Factor analysis was applied to identify the chemical combinations in each cluster. Ni, Ca2+, Sr2+ and Mg2+ appear as a factor in Wilgamuwa non-CKDu water sources. Hence, alkaline earth metals are chemically associated and appear as a factor combination in Wilgamuwa non-CKDu water sources. Also, Alkalinity, Hardness, Ca2+ and Sr2+ were found as a factor in Ginnoruwa CKDu samples.