EVALUATION OF GROUNDWATER QUALITY USING MULTIVARIATE STATISTICAL TECHNIQUES AND GIS - A CASE STUDY

This study deals with the evaluation of spatial variations in the groundwater quality in Rajam, Srikakulam district, Andhra Pradesh, India. The significant physicochemical parameters such as pH, conductivity, total dissolved solids, chlorides, total alkalinity, calcium hardness, magnesium hardness and sulphate were assessed. Pearson's Correlation technique, box plot, multivariate statistical tools such as cluster analysis and principle component analysis were applied to groundwater quality analysis. The groundwater samples were assessed for its applicability in irrigation and drinking purposes and geographic information system techniques are used for mapping consequence. The parameters analyzed were compared with Bureau of Indian Standards (BIS) and WHO standards. Box plot analysis revealed that total dissolved solids and electrical conductivity was strongly correlated. Correlation analysis reveals that pH shows weak correlation (r<0.5) with chlorides (r>0.383). Electrical Conductivity shows strong correlation (0.7.9) with Alkalinity (r>0.886) and Total Hardness was moderately correlated (0.5.7) with Mg (r>0.544), Cl (r>0.543), Su (r>0.508), but strongly correlated with TDS (r>0.863). Whereas Mg (r>0.544), Cl (r>0.543) and SO4 (r>0.508) was moderately correlated with Total Hardness (TH). SO4 was moderately correlated with Mg (r>0.664). Water quality index (WQI) for each sample was also determined. It is found that 3,5,18,19,20,21 well point samples are fit for drinking and most samples are having poor (50-100) quality for drinking. The data was analyzed with the help of Statistical tools and found that water samples are contaminated with the weathering of metamorphic rocks (charnockite, khondalite etc.,) present in the study area. Chlorinity Index and Salinity Index are found to be in permissible limits and hence suitable for irrigation purpose