Assessment of groundwater suitability for drinking and irrigation purposes with probable health threats in a semiarid river basin of South India

In the semiarid river basin of south India, the present study focuses on the appropriateness of water for drinking and irrigation as well as the risks to human health posed by pollutants. A total of 68 groundwater samples were evaluated for irrigation and consumption purposes. With a high electrical conductivity peaking at 3430 μS/cm and an alkaline composition, the groundwater has a high salinity and poor water quality. Durov's figure displays a trend along the dissolution or mixing line and identifies the geochemical facies of groundwater samples. According to water quality indexes, the majority of samples are categorized as unfit for human consumption (26.47%), extremely bad (36.76%), and poor (26.47%). According to elemental concentrations, the data are grouped into three clusters using hierarchical cluster analysis. According to the geographical distribution, nitrate levels are safe over about 320.25 km² and dangerous over about 121.10 km², whereas fluoride levels are safe over about 293.92 km² and dangerous over about 147.43 km². About 50.65 km², 14.70% of the samples, fell into the no restriction category for irrigation, indicating acceptable standards. Low sodium levels in soils are indicated by parameters like SAR, %Na, PI, RSC, MR, and KR; SAR values fall into the C2S1, C3S1, and C4S1 categories. According to Doneen's diagram, 70.5% of samples had a PI >75, indicating suitability; the Wilcox diagram classified 22.05% of samples as excellent and 69.11% as good to permissible for irrigation. According to human health risk assessment, 75% of babies, 63% of children, 75% of teens, and 54% of adults have THI values >1 for fluoride. About 45% of newborns, 42% of kids, 45% of teenagers, and 29% of adults are at risk for nitrate. Infants, kids, and teenagers are at the danger. In order to safeguard human health against fluoride and nitrate, the study emphasizes the necessity of efficiently managing groundwater resources, lowering agricultural pollution, and assuring clean drinking water. PRACTITIONER POINTS: In the area, 79.25 km² has good drinking water quality based on DWQI. Based on IWQI, 70.33 km² area is recognized as suitable for agricultural practices. Geogenic and anthropogenic activities contribute to fluoride and nitrate pollution in water. Based on THI, infants and children are more prone to fluoride and nitrate contamination.