| Abstract: | A conceptual model of eolian transport is proposed to address the widely distributed, high concentrations of hexavalent chromium (Cr+6) observed in ground water in the Emirate of Abu Dhabi, United Arab Emirates. Concentrations (30 to more than 1000 μg/L Cr+6) extend over thousands of square kilometers of ground water systems. It is hypothesized that the Cr is derived from weathering of chromium-rich pyroxenes and olivines present in ophiolite sequence of the adjacent Oman (Hajar) Mountains. Cr+3 in the minerals is oxidized to Cr+6 by reduction of manganese and is subsequently sorbed on iron and manganese oxide coatings of particles. When the surfaces of these particles are abraded in this arid environment, they release fine, micrometer-sized, coated particles that are easily transported over large distances by wind and subsequently deposited on the surface. During ground water recharge events, the readily soluble Cr+6 is mobilized by rain water and transported by advective flow into the underlying aquifer. Chromium analyses of ground water, rain, dust, and surface (soil) deposits are consistent with this model, as are electron probe analyses of clasts derived from the eroding Oman ophiolite sequence. Ground water recharge flux is proposed to exercise some control over Cr+6 concentration in the aquifer. |
| Genre: | Article |
| ProdID: | 70034068 |
| Citation Author: | Wood, W. W.; Clark, D.; Imes, J. L.; Councell, T. B. |
| Citation Contributing Office: | Ground-Water Research Program for the Emirate of Abu Dhabi, United Arab Emirates |
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| Citation End Page: | 29 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Groundwater |
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| Citation Phsyical Description: | 11 p. |
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| Citation Publisher: | Wiley |
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| Citation Search Results Text: | Eolian transport of geogenic hexavalent chromium to ground water; 2010; Article; Journal; Groundwater; Wood, W. W.; Clark, D.; Imes, J. L.; Councell, T. B. |
| Citation Start Page: | 19 |
| Citation Volume: | 48 |
| Citation Year: | 2010 |
| Type: | citation/reference |
| Text: | Eolian transport of geogenic hexavalent chromium to ground water; 2010; Article; Journal; Groundwater; Wood, W. W.; Clark, D.; Imes, J. L.; Councell, T. B. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1111/j.1745-6584.2009.00592.x |
| Date Other: | Fri, 1 Jan 2010 00:00 -0600 |
| Publisher: | Wiley |
