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Title: Final Scientific/Technical Report--In-Situ Generation of Iron-Chromium Precipitates for Long Term Immobilization of Chromium at the Hanford Site

Hexavalent chromium (Cr(VI)) is a toxic ground water contaminant widespread at the Hanford site and many other industrial facilities. A common remediation method for Cr(VI) is in situ reduction/immobilization, in which soluble Cr(VI) is reduced to the less soluble trivalent Cr (Cr(III)). If iron (Fe) minerals are present during the process, Cr(III) precipitates as a mixed Fe(III)-Cr(III) (Fe-Cr) solid. The objective of this exploratory research was to obtain preliminary evidence about the relationships among the method of Cr(VI) reduction (i.e., abiotic or microbial), the properties of the resulting Fe-Cr precipitates, and their tendencies to release soluble Cr(VI) in the presence of the common manganese oxide birnessite. The results of this exploratory research project show that the conditions of Cr(VI) reduction—specifically the ratio of Cr to Fe, and/or whether the Cr(VI) reductant is a mineral or a microorganism—can significantly affect the tendency of the resulting Fe-Cr precipitate to release Cr(VI) to the environment in the presence of birnessite. These results suggest the chosen remediation conditions have the potential to strongly influence not only the initial success of in situ Cr(VI) reduction/immobilization, but also the potential for successful long term sequestration of Cr in the form of stable soil precipitates.
 [1] ;  [1] ;  [1] ;  [2]
  1. University of Oklahoma
  2. Woods Hole Oceanographic Institution
Publication Date:
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Technical Report
Research Org:
University of Oklahoma/Woods Hole Oceanographic Institution
Sponsoring Org:
USDOE; USDOE SC Office of Biological and Environmental Research (SC-23)
Contributing Orgs:
University of Oklahoma, Woods Hole Oceanographic Institution
Country of Publication:
United States
54 ENVIRONMENTAL SCIENCES Chromium, in situ remediation, ground water contamination