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Lead and arsenic speciation and bioaccessibility following sorption on oxide mineral surfaces

Beak, Douglas Gerald
http://rave.ohiolink.edu/etdc/view?acc_num=osu1131933545

Abstract Details

2005, Doctor of Philosophy, Ohio State University, Soil Science.
The risk posed from incidental ingestion of arsenic-contaminated or lead-contaminated soil may depend on sorption of arsenate (As(V)) or lead (Pb(II)) to oxide surfaces in soil. Arsenate or lead sorbed to ferrihydrite, corundum, and birnessite model oxide minerals were used to simulate possible effects of ingestion of soil contaminated with As(V) or Pb(II). Arsenate or lead sorbed oxides were placed in a simulated gastrointestinal tract (in vitro) to ascertain the bioaccessibility of As(V) or Pb(II) and changes in As(V) or Pb(II) surface speciation. The speciation of As or Pb was determined using EXAFS and XANES analysis. The As(V) adsorption maximum was found to be 7.04 g kg-1, and 0.47 g kg-1 for ferrihydrite and corundum, respectively. The bioaccessible As(V) for ferrihydrite ranged form 0 to 5 % and for corundum ranged from 0 to 16 %. The surface speciation for ferrihydrite and corundum was determined to be binuclear bidentate. These results for As(V) sorbed to ferrihydrite and corundum suggest that the bioaccessibility of As(V) is related to the As(V) concentration, and the As(V) adsorption maximum. The bioaccessibility of As(V) sorbed to birnessite ranged from 16 to 28 % and the As(V) surface speciation was binuclear bidentate. The results for As (V) sorbed birnessite suggest that birnessite can reduce the bioaccessibility of As(V) in contaminated soil. Sorption of Pb(II) was significant for all the model oxides used. The sorption maximum was found to be 2.13 g kg-1 for corundum, 38.6 g kg-1 for ferrihydrite, and 127 g kg-1 for birnessite. The bioaccessible Pb(II) ranged from 53 to 88 % for ferrihydrite, Pb(II) concentrations greater than 200 mg kg-1 was greater than 85 % for corundum and below 200 mg kg-1 there was no bioaccessible Pb(II). There was no measurable bioaccessible Pb(II) for any concentration of Pb sorbed birnessite. The surface Pb(II) speciation was found to be: 1. Mononuclear bidentate for ferrihydrite, 2. Mononuclear bidentate and an outer-sphere complex for corundum, and 3. Binuclear bidentate, and trinuclear tridentate for birnessite. Ferrihydrite and corundum usefulness in Pb remediation would be limited when risk of incidental ingestion is of major concern.
Nicholas Basta (Advisor)
166 p.
Arsenic; Lead; bioaccessibility; bioavailability; Fe oxides; Al Oxides; Mn Oxides; Ferrihydrite; Corundum; Birnessite; As Speciation; Pb Speciation; EXAFS; XANES

Recommended Citations

Citations

  • Beak, D. G. (2005). Lead and arsenic speciation and bioaccessibility following sorption on oxide mineral surfaces [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1131933545

    APA Style (7th edition)

  • Beak, Douglas. Lead and arsenic speciation and bioaccessibility following sorption on oxide mineral surfaces. 2005. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1131933545.

    MLA Style (8th edition)

  • Beak, Douglas. "Lead and arsenic speciation and bioaccessibility following sorption on oxide mineral surfaces." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1131933545

    Chicago Manual of Style (17th edition)

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