Hydrochemical insights of groundwater for drinking, agriculture and potential nitrate threats in a part of Western India

A comprehensive hydrochemical insight was evaluated to groundwater suitability for drinking and agriculture, and potential nitrate threats in a part of Western India. Total 248 groundwater samples both in pre-monsoon (PrM) and post-monsoon (PoM) seasons were examined for the physicochemical parameters, and major ions by using standard methods, and their spatial distributions using GIS technique. Results show that major cations are influenced as Na + > Mg 2+ > Ca 2+ > K + ions in the PrM, and Ca 2+ > Na + > Mg 2+ > K + ions in the PoM. However, the major anions showed the influences of HCO 3 − > Cl − > SO 4 2− > NO 3 − > F − ions both in the seasons. The EC, TDS, TH values are found elevated in some parts. Elevated NO 3 − concentrations (the maximum: 199 mg/L in the PoM and 357 mg/L in the PrM) indicate the influence of agricultural activities. Groundwater is the dominant of two hydrochemical facies such as mixed Ca-HCO 3 type and Mixed Ca–Mg–Cl type waters in both seasons. Hydrochemical compositions are influenced mainly by the dissolution of host rock. The water quality index (WQI) demonstrates that about 29% and 36% of the samples are inappropriate for drinking during the dry and wet periods, respectively. The SAR, RSC, KR, PI, and PS indicate the water suitability for agriculture. The CR values support the necessity of replacing metallic pipes with PVC pipes for groundwater supply. The positive CAIs values indicate a large interchange among Na + and K + from water with the Ca 2+ and Mg 2+ of the parent rocks. Principal component analysis was performed to compare the similarities and dissimilarities of the ions simultaneously for the PrM and PoM samples. In addition, oral exposure to the NO 3 is found higher as compared to dermal interaction in the dry season. Total health index (HI Total ) values related to the non-carcinogenic health threats of nitrate in groundwater are an average of 1.414, 1.672, and 2.457 for males, females, and children, respectively, in the PrM, whereas 1.055, 1.246, and 1.832 in the PoM. Children are more health threats in the potential nitrate exposure.