Physicochemical and mineralogical characterization of soil-saprolite cores from a field research site, Tennessee.
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.
Moon
Ji-Won
JW
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
Roh
Yul
Y
Phelps
Tommy J
TJ
Phillips
Debra H
DH
Watson
David B
DB
Kim
Young-Jin
YJ
Brooks
Scott C
SC
D001673:Biodegradation, Environmental / Q000528:radiation effects; D002118:Calcium / Q000032:analysis / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods; D005069:Evaluation Studies as Topic; D008345:Manganese / Q000032:analysis / Q000737:chemistry; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D012990:Soil Pollutants, Radioactive / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013714:Tennessee; D014501:Uranium / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D014875:Water Pollutants, Radioactive / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology
D012987:Soil; D012990:Soil Pollutants, Radioactive; D014875:Water Pollutants, Radioactive; D008345:Manganese; D014501:Uranium; D002118:Calcium