Integrated hydrochemical and health-risk assessment of fluoride and major ions in groundwater from hattar and gadoon industrial estates, pakistan.

Groundwater contamination in industrial areas poses serious environmental and public-health concerns, particularly in rapidly urbanizing regions of Pakistan where aquifers are the primary source of potable and industrial water. This study evaluates the hydrochemical characteristics and fluoride (F-)-related health risks of groundwater in two major industrial estates, Hattar (Haripur District) and Gadoon Amazai (Swabi District), northwestern Pakistan. A total of 100 groundwater samples (50 per region) were analyzed for major ions and trace elements using ion chromatography (IC) and inductively coupled plasma-optical emission spectroscopy (ICP-OES). Groundwater exhibited alkaline conditions (pH 8.4-9.6) and moderate to high mineralization, dominated by sodium (Na⁺)-chloride (Cl-)-sulfate (SO₄2-)-calcium (Ca2⁺) facies. F- concentrations ranged from 0.17-0.53 mg L-1 in Hattar and 0.17-0.37 mg L-1 in Gadoon, remaining below the World Health Organization guideline of 1.5 mg L-1, whereas Cl⁻ varied widely (5.9-71.3 mg L-1 in Hattar; up to 371.7 mg L-1 in Gadoon), reflecting evaporite dissolution and effluent infiltration. Principal component analysis (PCA) extracted four components in Hattar and three in Gadoon, representing salinity-mineralization, industrial/nutrient inputs, and geogenic fluoride-pH controls. Correlation analysis confirmed strong associations among salinity-related parameters and weak coupling of F⁻ with other ions. Health-risk assessment based on the USEPA non-carcinogenic framework showed that oral ingestion dominated exposure (> 99%). Although F- concentrations were within guideline limits, children exhibited comparatively higher exposure levels, while oral hazard quotient (HQ) values remained within acceptable risk limits, indicating no significant non-carcinogenic risk under current conditions. The findings highlight the need for sustained groundwater monitoring, improved industrial wastewater management.