Hydrogeochemistry and Source Appraisal of Groundwater Quality in a Semi-Arid Region of Kadapa, India: Insights into Pollution, Health Risks

ABSTRACT Groundwater quality is a major concern in the semiarid regions such as Badvel, India, where the geogenic, and climatic factors are compounded by intensive agricultural activities, which may exacerbate the contamination risk. To assess this, 50 groundwater samples were collected and analysed for their physicochemical characteristics in the pre- and post-monsoon periods of 2023. pH, electrical conductivity (EC), total dissolved solids (TDS), major ions, total hardness (TH), and total alkalinity (TA) in groundwater were assessed, and a subsequent ion balance error (IBE) was conducted. Then, the pollution index of groundwater (PIG) and human health risk assessment (HHRA) were performed using established procedures. Moreover, the ionic sources were evaluated using conventional graphical, statistical and PHREEQC 3.7.3 simulation. Among all physicochemical parameters, TDS, Ca2+, Mg2+, Na+, K+, Cl− NO3− and F− were excess in groundwater. PIG revealed that (90%) of groundwater fell in the low pollution category, followed by moderate pollution (10%). The hazard quotient (HQ) for NO3− and F− in groundwater for the majority of samples was >1, indicating potential health risks to infants, followed by children, and adults. Notably lower PIG and HQ values were observed in post-monsoon groundwater compared to the pre-monsoon groundwater owing to the dilution effect of freshwater recharge. Moreover, precipitation of carbonate, sulphate, fluoride, and dissolution of chloride minerals were responsible for groundwater chemistry. Furthermore, the dominance of Na-Cl water facies and rock-water interaction were major chemical processes of groundwater. The dominance of F− in groundwater was attributed to the rock-water interaction, whereas the NO3− may be attributed to anthropogenic influences. Hence, prior water treatment and continuous monitoring are necessary to avoid potential health risks to residents of Badvel, India.