Arsenic mobilization in confined aquifers formed in glaciomarine deposits
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| Authors: | de Albuquerque, RC; Kirste, D; Allen, DM |
| Year: | 2010 |
| Journal: | : 703-706 |
| Title: | Arsenic mobilization in confined aquifers formed in glaciomarine deposits |
| Abstract: | Arsenic mobilization processes are investigated in confined aquifers formed by glaciomarine sediments in a temperate coastal region. The chemistry of groundwater in the studied aquifers is interpreted as being controlled by mineral weathering and cation exchange which caused these waters to be of a Na-HCO3 type. Mixing with connate seawater trapped in pore space appears to be occurring in one of the aquifers, resulting in a Na-Cl type groundwater. The groundwater with elevated arsenic is at a lower redox state and has basic pH, which are both conditions that favor arsenic mobilization. Arsenic is interpreted as being mobilized through desorption of anionic arsenic species at basic pH, reduction of arsenate to arsenite and dissolution of iron oxides and oxyhydroxides minerals. These processes are evidenced through observed positive relationships of arsenic with pH and iron. Mixing with connate seawater does not appear to contribute to arsenic mobilization. |
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