Groundwater is the most important natural resource used for drinking by many people around the world, especially in rural areas. An attempt has been made in this research paper to understand the groundwater quality of Pambar Sub-Basin in parts of Vellore and Krishnagiri districts, Tamil Nadu (India). Groundwater is the major source for domestic and agricultural activity in this area. Groundwater samples were collected from 41 wells during pre-monsoon period in the year 2010. The water samples collected in the field were analyzed for electrical conductivity, pH, total dissolved solids (TDS), major cations like calcium, magnesium, sodium, potassium, and anions like bicarbonate, chloride, nitrate, and sulfate, in the laboratory using the standard methods given by the American Public Health Association. The groundwater locations were selected to cover the entire study area and attention was given to the area where contamination is expected. Parameters exceeding permissible limit have been identified in most of the locations indicating higher ionic concentration. EC, TDS, Ca, Mg, Na, Cl and NO3 exceed the maximum permissible limit in the seasons. SO4 are within the permissible limit of WHO (2008) and BIS (1991) standard. The results were evaluated in accordance with the drinking water quality standards given by the World Health Organization. To know the distribution pattern of the concentration of different elements and to demarcate the higher concentration zones, the spatial interpolation maps for various elements were also generated, discussed, and presented. Present work aims to interpolate major ions concentration in groundwater by using ARC/GIS software.
