Читать книгу Groundwater Geochemistry - Группа авторов - Страница 15

As poses more adverse health impact to human than animals due to different gastrointestinal absorption. The consumption of As‐contaminated water damages human health, including respiratory distress resulting into laryngitis, bronchitis, or rhinitis, cardiovascular effects, and gastrointestinal effects like lips burning, pain while swallowing, abdominal pain, thirst, and nausea. Consumption of the inorganic As increases the risk of lung cancer, including the side effects of it such as headache, lethargy, hallucination, keratosis and hyperpigmentation in skins, seizures, and mental confusion (Mandal et al. 1996; CGWB 2014).

The organic and inorganic arsenic compound has been introduced in the water system through geological and anthropogenic sources. It is available in all geological material in variable concentration. Arsenic mobilization depends on three mechanisms in groundwater, which have been proposed:

1 Oxidation of arsenic‐bearing pyrite minerals.FeAsS +13Fe3+ + 8H2O → 14Fe2+ + SO42‐ + 13H+ + H3AsO4(aq)

2 Dissolution of As‐rich iron oxyhydroxides (FeOOH) under reducing conditions:8FeOOH‐As(s) + CH3COOH + 14H2CO3 → 8Fe2+ + As(d)+ + 16HCO3− + 12H2O

3 Release of As present in the aquifer media exchanged with phosphate (H2PO−) linked with percolation of phosphate ions into the aquifer when excess application is done in farming practices (Acharya et al. 1999; Pokhrel et al. 2009).

The dissolution of FeOOH under reducing conditions reflected the possible reason for the elevated concentration of arsenic in subsurface water (Harvey et al. 2002). Apart from these, arsenic shows a strong affinity for protein; the biological sources also contribute arsenic though the soil and water ecosystem. Arsenic exhibits a strong affinity for proteins, lipids, and other cellular components and as such, accumulates readily in living tissues (Ferguson and Gavis 1972). Besides this, arsenic concentration was observed high in the aquatic organism through the processes of biomagnification.