Geochemical characterization and health risk assessment of groundwater in Wadi Ranyah, Saudi Arabia, using statistical and GIS-based models

Groundwater in Wadi Ranyah, the main water source for local communities, was analyzed using 77 samples to evaluate physicochemical properties, major ions, and heavy metal concentrations. While most parameters met World Health Organization (WHO) standards, levels of arsenic, lead, cadmium, chromium, and nickel exceeded permissible limits. Hydrochemical analyses were conducted using Piper and Durov diagrams, alongside health risk assessments based on statistical ratios established by the United States Environmental Protection Agency (US EPA). The analysis identified two dominant water types (SO₄·Cl-Ca·Mg and HCO₃-Ca·Mg), influenced by ion exchange, evaporite dissolution, and silicate weathering. Health risk assessment, based on US EPA models, revealed significant non-carcinogenic and carcinogenic risks, particularly for children. Oral ingestion accounted for the majority of exposure, with arsenic and lead being the most hazardous. Dermal exposure risks were comparatively lower. The identified health threats include potential dermatological, cardiovascular, and neurological effects, and an increased cancer risk. Based on these findings, groundwater in Wadi Ranyah is unsuitable for drinking without treatment. Mitigation strategies such as reverse osmosis, ion exchange filtration, and continuous monitoring are recommended to reduce heavy metal contamination and protect public health.