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Eolian transport of geogenic hexavalent chromium to ground water

Ground Water

By:
, , ,
DOI: 10.1111/j.1745-6584.2009.00592.x

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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.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Eolian transport of geogenic hexavalent chromium to ground water
Series title:
Ground Water
DOI:
10.1111/j.1745-6584.2009.00592.x
Volume
48
Issue:
1
Year Published:
2010
Language:
English
Publisher:
Wiley
Contributing office(s):
Ground-Water Research Program for the Emirate of Abu DhabiUnited Arab Emirates
Description:
11 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
19
Last page:
29