Eolian Transport of Geogenic Hexavalent Chromium to Ground Water
- 23 December 2009
- journal article
- Published by Wiley in Groundwater
- Vol. 48 (1), 19-29
- https://doi.org/10.1111/j.1745-6584.2009.00592.x
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.Keywords
This publication has 22 references indexed in Scilit:
- Dust storms and dust at Abu Dhabi international airportWeather, 2007
- Genesis of hexavalent chromium from natural sources in soil and groundwaterProceedings of the National Academy of Sciences, 2007
- Solute and isotope constraint of groundwater recharge simulation in an arid environment, Abu Dhabi Emirate, United Arab EmiratesHydrogeology Journal, 2007
- Late Pleistocene eolian history of the Liwa region, Arabian PeninsulaGSA Bulletin, 2005
- Occurrence of hexavalent chromium in ground water in the western Mojave Desert, CaliforniaApplied Geochemistry, 2004
- Oxidation and toxicity of chromium in ultramafic soils in ZimbabweApplied Geochemistry, 2002
- Hydrology of the coastal sabkhas of Abu Dhabi, United Arab EmiratesHydrogeology Journal, 2001
- Critical Evaluation and Selection of Standard State Thermodynamic Properties for Chromium Metal and Its Aqueous Ions, Hydrolysis Species, Oxides, and HydroxidesJournal of Chemical & Engineering Data, 1998
- How wet is wet? Precipitation constraints on late quaternary climate in the southern Arabian PeninsulaJournal of Hydrology, 1995
- Paleoclimatic Reconstruction in Northern Oman Based on Carbonates from Hyperalkaline GroundwatersQuaternary Research, 1990