Groundwater arsenic contamination

Groundwater arsenic contamination is the presence of dissolved arsenic at harmful concentrations in groundwater. It commonly arises when geochemical conditions release arsenic from sediments or rocks.

Redox potential: A measure of a chemical environment’s tendency to accept or donate electrons. Low-oxygen conditions can dissolve iron minerals and release arsenic into groundwater.
Holocene aquifers: Groundwater-bearing sediments deposited during the Holocene epoch, beginning about 11,700 years ago. Young alluvial deposits are a major setting for severe arsenic contamination in South Asia.
Arsenic testing in drinking water: Measurement of arsenic concentration in water using field kits or laboratory methods. Testing identifies unsafe wells because arsenic is colorless and tasteless.
Chronic arsenic poisoning: Illness caused by prolonged exposure to arsenic, especially through contaminated drinking water. Groundwater exposure can continue for years before distinctive symptoms appear.
Iron oxyhydroxides: Iron minerals that form in soils and sediments and can bind dissolved elements to their surfaces. Arsenic often accumulates on these minerals before being released as they dissolve.
Bengal Basin: A large sedimentary basin spanning Bangladesh and eastern India. Its deltaic aquifers contain some of the world’s most extensive naturally arsenic-rich groundwater.
Arsenic removal from water: Processes that reduce arsenic concentrations in water through separation or chemical treatment. Treatment can make contaminated groundwater safer when reliable alternative sources are unavailable.
Arsenicosis: A chronic disease caused by prolonged arsenic exposure, often marked by skin changes and systemic illness. It is a visible consequence of sustained consumption of arsenic-contaminated groundwater.
Arsenic speciation: The distribution of an element among its chemical forms in a sample. Arsenite and arsenate differ in mobility, toxicity, and removal behavior.
Ganges–Brahmaputra Delta: A vast river delta formed by sediment from the Ganges, Brahmaputra, and Meghna river systems. Its organic-rich sediments and shallow aquifers create conditions that mobilize arsenic.

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