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Bioaccessibility, Bioavailability, and Chemical Speciation of Arsenic in Contaminated Soils and Solid Wastes

Stevens, Brooke Nan
http://rave.ohiolink.edu/etdc/view?acc_num=osu1469101685

Abstract Details

2016, Doctor of Philosophy, Ohio State University, Environmental Science.
Arsenic in soil and solid waste is one of the most common contaminants of concern that exceed risk criteria at many Department of Defense (DoD) sites. Ingestion of soil contaminated with high levels of As is the primary human health risk driver at many of the sites. Use of contaminant total content instead of bioavailability in human health risk assessment is often overly conservative and can result in costly and unnecessary soil remedial action. The binding mechanisms and speciation of As in soil impact contaminant bioavailability. Twenty-seven As contaminated soils and solid wastes that represent a wide variety of properties and As sources from DoD installations, industrial sites, residential, and agricultural sites were studied. Total As content ranged from 162 to 12,500 mg As/kg material with a median value of 464 mg As/kg material. Relative bioavailable (RBA) As was determined by the adult mouse and the juvenile swine bioassays. Relative bioavailable As ranged from 6.37 to 81.2%. Swine RBA As was greater than mice RBA As. However, variability in RBA As was higher for swine than mice. In vitro bioaccessible (IVBA) As was determined by the U.S. EPA Method 9200 (glycine), PBET, UBM, OSU IVG, and CAB methods. In vitro bioaccessible As ranged from less than 1% to 100%. Median and mean IVBA As followed the trend CAB (pH 1.5) was greater than UBM (pH 1.2), OSU IVG (pH 1.8), PBET (pH 1.8), and glycine (pH 1.5) which were approximately equal. In vivo-in vitro correlations (IVIVC) were used to evaluate the ability of IVBA methods to predict RBA. In vivo-in vitro correlation analysis showed all of the IVBA methods were predictive of RBA for both the mice and swine bioassays. Physiology based IVBA methods (UBM and OSU IVG) produced IVIVC that are more predictive of RBA. The CAB method is more accurate for low RBA As materials and for materials with high reactive Al and Fe oxides. Arsenic speciation determined using X-ray absorption spectroscopy was predictive of 21% and 36% of RBA As determined using the adult mouse and juvenile swine methods, respectively. Despite As(V) adsorbed to mineral surfaces (i.e., Fe oxides) being a major component of most soils and solid wastes (>50%), these materials ranged from ~20-80% in IVBA As and widely ranged in RBA As. Arsenic speciation can provide a conservative estimate of RBA As. Arsenic speciation is very important to provide information on IVBA or RBA As results and/or determine a priori if a bioavailability-based risk assessment is justified.
Nicholas Basta, Ph.D. (Advisor)
194 p.
Environmental Science

Recommended Citations

Citations

  • Stevens, B. N. (2016). Bioaccessibility, Bioavailability, and Chemical Speciation of Arsenic in Contaminated Soils and Solid Wastes [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469101685

    APA Style (7th edition)

  • Stevens, Brooke. Bioaccessibility, Bioavailability, and Chemical Speciation of Arsenic in Contaminated Soils and Solid Wastes. 2016. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1469101685.

    MLA Style (8th edition)

  • Stevens, Brooke. "Bioaccessibility, Bioavailability, and Chemical Speciation of Arsenic in Contaminated Soils and Solid Wastes." Doctoral dissertation, Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1469101685

    Chicago Manual of Style (17th edition)

osu1469101685
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This open access ETD is published by The Ohio State University and OhioLINK.