Fluoride contamination and human health risks assessment in groundwater from community tube wells in Kamber Shahdadkot, Sindh, Pakistan.

Groundwater fluoride (F⁻) contamination poses a significant global public health challenge, with over 200 million people worldwide exposed to concentrations exceeding safe limits. This comprehensive study evaluates F⁻ contamination and associated health risks in the community tube wells across Kamber Shahdadkot district, Sindh Province, Pakistan. A total of 53 GW samples were collected and systematically analyzed for 15 hydrochemical parameters including major ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃⁻, SO₄²⁻, Cl⁻, NO₃⁻), trace elements (Fe²⁺, F⁻), and physicochemical properties (pH, turbidity, TDS, EC, depth). Fluoride concentrations ranged from 0.2 to 7.1 mg/L with a mean of 1.82 mg/L, where 42% of samples exceeded WHO permissible limits (1.5 mg/L). Hydrogeochemical analysis revealed predominant CaHCO₃ water type, with Gibbs diagrams indicating rock-water interaction as the primary control mechanism. The saturation indices indicated supersaturation concerning calcite, dolomite, fluorite, goethite, and hematite, highlighting the geogenic fluoride sources through mineral dissolution processes. PCA identified both natural and anthropogenic contamination sources. Quantile-Quantile plotting validated normal distribution of parameters with R² values ranging from 0.720 to 0.986. Health risk assessments, using average daily dose (ADDingestion) and Hazard Quotient (HQingestion) calculations, revealed significant risks, across all demographic groups, with children facing the highest exposure (mean HQ: 2.02), followed by females (1.65), and males (1.17). WQI assessment indicated 51% of samples unsuitable for consumption. These findings underscore the urgent need for comprehensive groundwater management strategies and alternative water supply systems to protect vulnerable populations in rural Sindh Province.