Chemometric appraisal of groundwater quality for domestic, irrigation and industrial purposes in Lower Bhavani River basin, Tamil Nadu, India

Groundwater quality in the Lower Bhavani River basin has been evaluated for drinking, irrigation and industrial purposes. To study drinking water quality, the Water Quality Index (WQI) method was applied along with classic hydrochemical methods, and the results then compared with World Health Organisation (WHO) standards. TDS and other ionic constituents showed that 66% of the samples were good qualityfor drinking water. These results are compatible with the WQI results, which showed 64% of the samples were excellent or good quality. High values of WQI are associated with elevated fluoride and nitrate concentration. A spatial variation map shows that the southern region of the basin havelower quality water compared to the central region. Both natural and anthropogenic activities, such as industrial effluents, agricultural fertilisers etc., influence the groundwater quality. Analysis of groundwater quality for irrigation purposes shows that the water is prone to have a medium to high salinity hazard. While the sodium absorption ratio (SAR) of the groundwater shows that 98% of the samples are excellent for irrigation and the permeability index (PI) shows that 63% of the samples are excellent for irrigation, on the other hand, the water is unfit in around 55% of samples in terms of magnesium hazard (MH) and Kellys index (KI) because a higher than normal concentration of Mg, Ca and K is observed. In the water quality parameters for industrial purposes, Langelier Index (LI) and Aggressive Index (AI)showed significant scaling tendency. In contrast to this, Puckorius Index (PI), Ryznar Stability Index (RI) and Larson-Skold Index (LS) indicate that the water samples have significant corrosion tendencies.Routine monitoring of water quality is suggested in the regions where groundwater quality issues are reported in this study.