Abstract
Assessment of water quality in a region is important as water is used for domestic and agricultural purposes. In most parts of south India groundwater is used extensively for domestic and agricultural purposes. The aim of this study was to assess the water quality of Kalpakkam region based on the major ions. Geologically, this study area has two distinct formations: crystalline charnockite rocks of Archean age and quaternary/recent sediments. The quaternary/recent sediments, weathered and fractured crystalline charnockite function as an unconfined aquifer system. The hydrogeochemical characteristics of water and its quality were studied from physico-chemical analysis of the water samples. Two characteristic facies were determined based on the results of hydrochemical analyses: (1) Na-Cl and (2) Ca-Mg-Cl facies are dominant in this region. Groundwater from the study unit is generally good for drinking purposes. However, samples from some wells exceeded drinking water standards established by the BIS for EC, TDS, sodium, chloride and sulphate ions.