Mineralogical characterization of saprolite at the FRC background site in Oak Ridge, Tennessee

Journal Article · Mon Dec 01 04:00:00 EST 2008 · Environmental Geology

OSTI ID:982102

Kim, Young-Jin ^[1]; Moon, Ji Won ^[2]; Roh, Yul ^[3]; Brooks, Scott C ^[2]

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1. Seoul National University
2. ORNL
3. Chonnam National University, Gwangju

The Field Research Center (FRC) including five contaminated sites and a clean background area was established in Oak Ridge, Tennessee, as a part of the U.S. Department of Energy's Natural and Accelerated Bioremediation Research (NABIR) program. This study investigates the mineralogy and mineralogical pathways of saprolite at the FRC background site to provide a fundamental basis for the remediation strategy for contaminated sites. The background site is underlain interbedded shales, siltstones, and limestones with nearly identical characteristics to the contaminated sites. Bulk samples of saprolite were collected by hand picking approximately at 1 m depth (C horizon) from the soil surface. The soil pH of 4.3 and cation exchange capacity (CEC) of 10.5 cmol/kg measured are in the range of the typical shallow depth saprolite layer in this area. Total Fe by citrate-bicarbonate-dithionate (CBD) and ammonium oxalate extractable (amorphous) were 17.6 and 0.61 g/kg, respectively. Total Mn extracted by NH{sub 2}OH{center_dot}HCl was 0.17 g/kg. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicate that quartz, illite, and microcline (K-feldspar) are the dominant minerals, occupying 95% of mineral composition. The saprolite samples analyzed have shown characteristics of oxic conditions overall, and the degrees of weathering for three sampling locations were various, most for S1 and least for S3, likely influenced either by the flow channels developed through saprolite or by seasonal fluctuation of the groundwater table. The source of the manganese oxide that observed from the site is likely to be Mn-rich muscovite in the shale or Mn-rich biotite in the blackish band in the limestone. The results such as abundant Mn and Fe contents identified encouraging prospects for conducting remediation projects in FRC sites.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 982102
• Journal Information: Environmental Geology, Journal Name: Environmental Geology Journal Issue: 6 Vol. 58
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BIOREMEDIATION
BIOTITE
CATIONS
FELDSPARS
FLUCTUATIONS
ILLITE
ION EXCHANGE
LIMESTONE
MANGANESE OXIDES
MINERALOGY
MUSCOVITE
OXALATES
QUARTZ
SAMPLING
SCANNING ELECTRON MICROSCOPY
SHALES
SILTSTONES
SOILS
WEATHERING
X-RAY DIFFRACTION