A Comprehensive Review of Global Groundwater Quality, Hydrochemistry, and Health Risk Assessments

Groundwater serves as a primary source of drinking and irrigation water across the world, particularly in developing regions where surface water is scarce. However, increasing anthropogenic activities, geogenic influences, and climatic variability have resulted in deteriorating groundwater quality. This review synthesizes findings from ten recent peer-reviewed studies from Africa, Asia, and the Middle East. The selected studies evaluate heavy metal contamination, hydrochemical processes, water quality index (WQI), multivariate statistical assessments, GIS-based mapping, spatiotemporal variability, and human health risks. Results reveal widespread contamination by arsenic, lead, cadmium, nitrate, fluoride, and other ions, with significant non-carcinogenic and carcinogenic health impacts. Hydrochemical analyses indicate that water–rock interactions, ion exchange, and anthropogenic pollution play dominant roles. This review emphasizes the need for integrated groundwater monitoring, sustainable management approaches, and advanced spatial–temporal tools to ensure groundwater safety.