An investigation into the influence of climate extreme on groundwater regimes and human health in the Periyar Basin: A fast growing urban centre in India.

A total of 212 groundwater samples were collected during North East Monsoon (NEM), South West Monsoon (SWM), Pre-Monsoon (PREM), and Post-Monsoon (POM) seasons of 2020-2021 from the Periyar River Basin, draining the south western flanks of Western Ghats. The analytical results revealed the order of abundance of cations as Ca²⁺ > Na⁺ > Mg²⁺ > K⁺ and anions in the order of HCO₃^- > Cl^- > SO₄^2- > NO₃^- for all seasons. The major hydrochemical facies identified were CaHCO₃ and mixed Ca-Mg-Cl in all the seasons with rock-water interaction as the key process regulating water chemistry. Ionic ratios of Ca²⁺ + Mg²⁺/Na⁺ + K⁺ and Ca²⁺/Mg²⁺ suggested significant effect of silicate minerals and other sources. The Water Quality Index (WQI) shows that the majority of the samples, namely, 98% in NEM, 86% in POM, 82% in PREM, and 95% in MON, fall in the categories ranging from excellent to good for drinking purposes. Furthermore, the health risk assessment based on carcinogenic and non-carcinogenic risk of the United States Environmental Protection Agency (US EPA) during monsoon and non-monsoon seasons for adults and children revealed the potential risk posed by Pb via oral exposure in the study area suggesting children being more susceptible to the damaging effects than adults.