Geochemical characterization and WQI based assessment of groundwater quality Using GIS in tropical river basin: Case study in Kirama-ara River basin, Southern Province, Sri Lanka.

Abstract

Abstract In the Kirama-ara River basin, Matara, southern region of Sri Lanka, a variety of agricultural inputs are utilized, and flooding is a common hazard. As a result, the complete physicochemical profile of the groundwater in the Kirama-ara river basin is yet undiscovered. Therefore, the goals of this study were to (a) identify the geochemical characteristics and changes in water quality, (b) evaluate non-carcinogenic health risk and develop a GWQI, and (c) generate a spatial distribution map for groundwater physicochemical parameters in the Kirama-ara river basin in Matara, Sri Lanka. The physiochemical characteristics of 16 groundwater samples, including pH, electrical conductivity (EC), total dissolved solids (TDS), Na+, K+, Ca2+, Mg2+, Cl−, NO3−, PO43−, and SO42−, were examined for spatial and temporal variations. The pH, NO3−, and PO43− values of 50%, 6.25%, and 12.5% of the samples, respectively, were determined to be beyond the allowable limit by both the WHO and SLS. The physicochemical investigation demonstrates that while 87.5% of the locations were acceptable for drinking, 12.5% of them lacked sufficient amounts. The most common hydro-chemical facies were Ca2+-Mg2+-HCO3−, mixed Ca2+-Mg2+-Cl− face, and Ca2+-Cl−. Rock weathering has a profound impact on the ionic composition and chemistry of groundwater. Additionally, health risk assessment research conducted in accordance with United States Environmental Protection Agency rules revealed that children face greater health risks than adults. To build reasonable management plans for long-term groundwater quality conservation and public health, more research is required.