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TRANSPORT AND TRANSFORMATION OF HEXAVALENT CHROMIUM THROUGH SOILS AND INTO GROUND WATER
Citation:
Puls, R., D. Clark, C. Paul, AND J. Vardy. TRANSPORT AND TRANSFORMATION OF HEXAVALENT CHROMIUM THROUGH SOILS AND INTO GROUND WATER. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/315 (NTIS PB94197597).
Description:
A detailed characterization of the underlying and adjacent soils of a chrome-plating shop was performed to provide information on the extent of soil and aquifer contamination at the site and on the potential for off-site migration and environmental impact. ntact, moist cores were obtained from more than 40 different locations, resulting in more than 200 discrete samples for total metal analysis, selective extraction tests, and adsorption-reduction experiments to assess the chemical speciation and distribution of chromium on the contaminated soils and its leaching potential. urface analytical techniques were also used to determine chemical speciation and to further elucidate mineral fractions responsible for retention of the chromium on the soils and sediments. dsorption and reduction capacities of the saturated aquifer sediments were variable and low, while the unsaturated soils' reduction capacities were much greater and were correlated with depth (decreasing capacity with increasing depth). he soils' adsorption and reduction capacities were eventually overwhelmed, however, and permitted the passage of Cr(VI) into the underlying ground water. dsorption capacity differences were primarily related to clay content and pH and less so to the presence of amorphous iron oxide coatings on matrix minerals as operationally defined by the selective extraction methods used in the study. eduction of CR(VI) to Cr(III) and subsequent precipitation as (Fe, Cr)(OH), is proposed as the primary attenuation mechanism in the unsaturated soils immediately beneath the shop, based on extraction and surface analyses results.