Hydrochemical Evaluation of Groundwater Quality and Human Health Risk Assessment of Fluoride and Nitrate: A Case Study of Pratapgarh District UP, India

Various of factors have contributed to groundwater contamination in the Indo-Gangetic alluvium, including mineral deposits, ion exchange, precipitation, overexploitation, and dissolution. In the current study, 40 different groundwater samples were sampled from different locations of Sadar block Pratapgarh district, Uttar Pradesh and various physicochemical parameters were evaluated. This research aims to investigate the groundwater quality associated with human health risks in all seasons (pre-monsoon, monsoon, and post-monsoon), analyze the reasons for seasonal differences, and identify areas with severe pollution. The water quality in PrM is 48%, in PoM it is 50%, and 48% of the sampling sites are categorized as highly polluted due to high THI value. THI values depict the highest F⁻ and NO₃⁻ contamination levels at PG 13 and P33 (THI > 5.0) in the PrM. After a health risk assessment, it was found that children and females are highly susceptible to health risks. The strongest correlation was found between TDS, EC, and fluoride (r = 0.9). This study would be extremely helpful to aid officials in identifying alternative drinking water resources in affected areas. The Piper plot revealed the presence of Cl⁻ and some SO₄⁻ type waters, which indicates strong acid dominance over weak acids, and the cation is dominated by Ca²⁺ and some of the Mg²⁺ type waters, indicating alkaline earth metal is dominating over alkali metals. Na–K-SO₄-Cl and Ca-Mg-SO₄-Cl mixed water type (23% Prm, PoM, and MoN) facies were detected. According to Gibbs’s plot, most of the samples with "evaporation dominance" and the rest are under “rock-water interaction”.