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Main Title Distribution, Speciation, and Transformation of Chromium in Contaminated Soils and Aquifer Sediments.
Author Puls, R. W. ; Paul, C. J. ; Clark., D. A. ;
CORP Author Robert S. Kerr Environmental Research Lab., Ada, OK. ;ManTech Environmental Technology, Inc., Ada, OK.
Publisher 1992
Year Published 1992
Report Number EPA/600/A-92/084;
Stock Number PB92-179092
Additional Subjects Chromium ; Land pollution control ; Waste disposal ; Water pollution control ; Sediments ; Electroplating ; Path of pollutants ; Environmental transport ; Ground water ; Aquifers ; Sediment-water interfaces ; Reduction(Chemistry) ; Extraction ; Ion exchanging ; Scanning electron microscopy ; X ray analysis ; Reprints ;
Library Call Number Additional Info Location Last
NTIS  PB92-179092 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 6p
Knowledge of the chemical speciation and distribution of chromium at hazardous waste sites is essential for adequate site characterization and risk assessment. Contaminant speciation, whether dissolved or in association with solid surfaces, will affect the toxicity and mobility of most contaminants in subsurface systems. This is particularly true of chromium, which exists as Cr(VI) and Cr(III) species in subsurface systems. The chemical speciation and distribution of chromium on unsaturated contaminated soils, and saturated aquifer sediments was analyzed in the vicinity of a chrome plating operation. Sequential extractions and selective ion exchange experiments were performed to infer mineral fractions responsible for retention of the chromium on the solid phase, and the chemical form (speciation) of the retained chromium. Reduction of Cr(VI) to Cr(III) and subsequent precipitation as (Fe,Cr) (OH)3 is proposed as the primary attenuation mechanism in the unsaturated soils immediately beneath the shop. Chromium reduction in the saturated aquifer sediments is significantly less effective in attenuation of the delineated Cr(VI) ground-water plume. Scanning electron microscopy with energy dispersive X-ray analyses, and cursory modelling efforts with CHROMAT were also used to complement wet chemical methods in assessments of chromium transport and transformation.