Review of processes controlling arsenic retention and release in soils and sediments of Bengal basin and suitable iron based technologies for its removal

• Published in: Groundwater for sustainable development 2019-04, Vol.8, p.358-367
• Main Authors: Banerji, Tuhin, Kalawapudi, Komal, Salana, Sudheer, Vijay, Ritesh
• Format: Article
• Language: English
• Subjects: Anoxic phase; Arsenic removal; Arsenite oxidation; Bengal basin; Iron
• ISSN: 2352-801X; 2352-801X
• DOI: 10.1016/j.gsd.2018.11.012

Arsenic in the soil environment has gained renewed interest because of the emerging cognizance that arsenic poisoning is a global concern. Groundwater in the Bengal Basin is significantly polluted by naturally occurring arsenic (As), a toxic metalloid, which adversely affects human health and among the countries facing As contamination problems, India and Bangladesh are the most affected. In soils and sediments, arsenic is often associated with Fe(III) (hydr)oxides and multiple processes/reactions govern its release into groundwater, including abiotic or biotically mediated oxidation-reduction and ligand exchange reactions. Reductive dissolution of arsenic-bearing Fe(III) (hydr)oxides and As(V) reduction to As(III) are the two main mechanisms controlling arsenic partitioning in soils, sediments and groundwater. Even though arsenic reduction is favourable over a wide range of conditions, Fe(III) reduction in nature is dependent on the biotic systems. This review reflects the current state of research for the understanding of arsenic in the soil environment with an emphasis on iron based technologies for its removal. It attempts to collate all the relevant literature such that it can be a useful resource for researchers or policy makers to help recognize and explore useful treatment options. [Display omitted] •Groundwater in the Bengal Basin is contaminated by naturally occurring arsenic (As) which is responsible for mass poisoning.•Reductive dissolution of arsenic-bearing Fe(III) (hydr)oxides and As(V) reduction to As(III) are the two main mechanisms controlling arsenic partitioning in soils, sediments and groundwater.•Iron-based technologies are very effective in removal of arsenic from groundwater and are more preferred as naturally arsenic is present in soil bound to iron oxides.•Community scale water treatment systems are more preferred than household/domestic systems due to its cost-effectiveness and ease of monitoring.