Temporal variations in hydro-geochemistry and potential health risk assessment of groundwater from lithological diversity of semi-arid region, Western Gujarat, India

The temporal changes in hydro-geochemistry of groundwater from lithological diversity of Amba Dongar area were assessed from human health risk point of view. In view of this, 104 samples were collected in post- (POM) and pre-monsoon (PRM) seasons to understand the ionic concentrations and seasonal variations in major cations and anions. Based on concentration of physicochemical parameters it is inferred that groundwater quality is good for drinking and most of the parameters are within allowable limit of the World Health Organisation (WHO). However, EC, TDS, Ca²⁺ and HCO₃⁻ exceed the desirable while NO₃ and F content are found beyond the permissible limits. The results 33% and 15% samples for nitrate and 60% and 63% samples for fluoride in POM and PRM, respectively, are above permissible limits of WHO, indicating a high health risk to inhabitants. The Piper's trilinear diagram depicts Ca²⁺–Mg²⁺ HCO₃⁻ as major water type in both the seasons and the plots diagram that the chemical rock weathering and rock–water interaction are responsible for modifying the groundwater chemistry. Further, the total hazard index indicates that children have higher risk than adults in both. Hence, antipollution filters and rainwater recharging structures are recommended as an action to be taken to lessen the health hazard.