Physicochemical and mineralogical characterization of soil-saprolite cores from a field research site, Tennessee

J Environ Qual. 2006 Aug 9;35(5):1731-41. doi: 10.2134/jeq2005.0123. Print 2006 Sep-Oct.

Abstract

Site characterization is an essential initial step in determining the feasibility of remedial alternatives at hazardous waste sites. Physicochemical and mineralogical characterization of U-contaminated soils in deeply weathered saprolite at Area 2 of the DOE Field Research Center (FRC) site, Oak Ridge, TN, was accomplished to examine the feasibility of bioremediation. Concentrations of U in soil-saprolite (up to 291 mg kg(-1) in oxalate-extractable U(o)) were closely related to low pH (ca. 4-5), high effective cation exchange capacity without Ca (64.7-83.2 cmol(c) kg(-1)), amorphous Mn content (up to 9910 mg kg(-1)), and the decreased presence of relative clay mineral contents in the bulk samples (i.e., illite 2.5-12 wt. %, average 32 wt. %). The pH of the fill material ranged from 7.0 to 10.5, whereas the pH of the saprolite ranged from 4.5 to 8. Uranium concentration was highest (about 300 mg kg(-1)) at around 6 m below land surface near the saprolite-fill interface. The pH of ground water at Area 2 tended to be between 6 and 7 with U concentrations of about 0.9 to 1.7 mg L(-1). These site specific characteristics of Area 2, which has lower U and nitrate contamination levels and more neutral ground water pH compared with FRC Areas 1 and 3 (ca. 5.5 and <4, respectively), indicate that with appropriate addition of electron donors and nutrients bioremediation of U by metal reducing microorganisms may be possible.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biodegradation, Environmental / radiation effects
  • Calcium / analysis
  • Calcium / chemistry
  • Environmental Monitoring* / methods
  • Evaluation Studies as Topic
  • Manganese / analysis
  • Manganese / chemistry
  • Soil / analysis*
  • Soil Microbiology*
  • Soil Pollutants, Radioactive / analysis*
  • Soil Pollutants, Radioactive / chemistry
  • Soil Pollutants, Radioactive / metabolism
  • Tennessee
  • Uranium / analysis*
  • Uranium / chemistry
  • Uranium / metabolism
  • Water Pollutants, Radioactive / analysis*
  • Water Pollutants, Radioactive / chemistry
  • Water Pollutants, Radioactive / pharmacology

Substances

  • Soil
  • Soil Pollutants, Radioactive
  • Water Pollutants, Radioactive
  • Manganese
  • Uranium
  • Calcium