Understanding nexus between hydrogeochemical cycling and medical geology of arsenic

Abstract

Geogenic arsenic (As) contamination is an internationally important environmental and human health issue posing threat to over 250 million people globally, either through ingestion of As-contaminated drinking water or via consumption of food contaminated with As. The medical geology of As is associated with its hydrogeochemical cycling releasing it geogenically from naturally occurring As-bearing minerals and bioaccumulation in food and humans. Arsenic has a complex biogeochemical cycling that mainly depends on redox potential (Eh), pH, dissolved organic carbon (C), iron/manganese oxides, and native microbial community. Consumption of As via food or water can cause various diseases such as gastric irritation, reduced red and white blood cells, arrhythmia, vascular injury, and both hands needling influenza even in low concentrations, while long-term As exposure can cause thickening of the skin, damage to finger and toenails, and darkening the appearance of small corn or warts on the palms, soles, and torso. In this chapter, we elucidated As sources, speciation, and its release mechanisms associated with hydrogeochemical cycling of As, leading to As toxicity and health hazards in humans under both acute and chronic exposures. Also, some case studies have been discussed to develop a critical understanding of As exposure and human health issue, as well as the possible As remediation approaches.