Hydrogeochemical signatures and suitability assessment of groundwater with elevated fluoride in unconfined aquifers Badin district, Sindh, Pakistan

The fluoride pollution in the groundwater is a significant human health risk around the world. However, many diseases including dental, crippling and skeletal fluorosis cause due to high fluoride contamination in the drinking water. The objectives of this study were to investigate the occurrence of higher F− in the groundwater, geochemical composition, water type mechanism for minerals enrichment and groundwater quality for drinking and irrigation purposes. Therefore, fifty-seven groundwater samples were collected for the appraisal. The mean concentrations of physical parameters like depth, Temperature, electrical conductivity, total dissolved solid, power of hydrogen ion (pH) and turbidity were observed as 28 m, 19.78 °C, 2283 uS/cm, 1456 mg/L, 7.4 and 21.80 NTU respectively. Whereas, the mean concentrations of chemical parameters such as cations (Ca+2, Mg+2, Na+ and K+) were observed to be (92.12, 83.63, 251 and 12.40) mg/L and anions (Cl−, SO42−, HCO3−, NO3− and F−) were (375, 300, 285, 4.9 and 1.9) mg/L respectively. While the mean concentration of total Fe in the drinking water samples of study are were reported as 0.28 mg/L respectively. The range concentration of F− were 0.23–6.8 mg/L shows that 47% of drinking water samples exceeded the WHO limit (1.5 mg/L). The piper plot resulted in the dominance of (NaCl), and Gibbs plot represents rock and precipitation dominance ratios; while SAR and Sodium percentage (Na %) validates the salinity and sodium risk to the use of groundwater for irrigation purposes. Saturation indices expressed; the saturation of the fluorite mineral found within the range of (− 2.3 to 1.24). PCA results reveals four significant factors with total percentage contribution were 70.73%. Whereas, the water quality index resulted with mean and standard deviation as (2502.62 ± 2164). The overall quality of the groundwater is unfit for human consumption and irrigation purposes to the local population of the study area.