Arsenic contamination in groundwater sources: Geochemical transformations, health hazards, toxicity and sustainable remediation technologies

Abstract

Arsenic contamination of groundwater represents one of the most significant geogenic and anthropogenic environmental health challenges of the modern era. Naturally occurring Arsenic, released through complex geochemical processes involving reductive dissolution of iron oxyhydroxides, oxidative weathering of sulfide minerals, and desorption under alkaline conditions, affects aquifers across Asia, the Americas, and parts of Europe and Africa. Chronic exposure via drinking water leads to Arsenicosis, characterized by skin lesions, cardiovascular disease, neurological impairment, and elevated risks of cancers of the skin, bladder, lung, and other organs. Toxicity is driven primarily by the greater mobility and cellular reactivity of arsenite (As(III)) relative to arsenate (As(V)), involving disruption of enzyme systems, generation of reactive oxygen species, interference with DNA repair, and epigenetic alterations. Regional comparisons reveal extreme contamination in the Bengal Basin (Bangladesh and West Bengal, India), the Red River and Mekong deltas, the Pampa plain of Argentina, and parts of China and the western United States, with concentrations frequently exceeding the World Health Organization guideline of 10 µg/L by one to two orders of magnitude. Sustainable remediation approaches encompass oxidation-coagulation-filtration, adsorption onto iron-based media, ion exchange, membrane processes, and emerging biological and hybrid technologies. This review synthesizes geochemical controls, health and toxicity mechanisms, regional patterns, and technology performance, emphasizing the need for context-specific, low-cost, and environmentally sound solutions that minimize secondary waste and support long-term water security.