Arsenic Leaching from Mineral Sorbents under Landfill Conditions and Arsenic Transport by Wind
KeywordsArsenic transport by wind
AdvisorEla, Wendell P.
Saez, Avelino E.
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
EmbargoDissertation not available in either the UA Campus Repository or the ProQuest Dissertations and Theses database, at the request of the author.
AbstractThe capacity of four mineral sorbents to retain arsenic under simulated mature landfill conditions was tested using semi-batch and continuous flow columns. The sorbents tested were Fe-, Ti-, La-, and Zr- based oxi(hydroxides). The Fe sorbent was included as a positive control to compare the release of As from a substrate subject to reduction to those of the, non-sensitive to reduction under typical mature landfill conditions, Ti, La, and Zr media. It has been proved that under mature landfill conditions, As(V) preloaded on ferric sorbents is prompt to be released at high levels. Our results indicate that Ti, La, and Zr sorbents can release As at a similar or higher degree than a ferric sorbent. In a second phase, the capacity of the same sorbents to retain As was evaluated after being subject to polymeric encapsulation in an epoxic resin. Landfill conditions were simulated by use of semi-batch column systems packed with compost and fed with actual landfill leachate. Results obtained indicated that encapsulation highly enhanced As retention of the media under simulated landfill conditions. In our research regarding soil contamination by atmospheric transport from mine tailings, a previously developed deposition forecasting model (DFM) that is designed to model the transport of particulate As and Pb from mine tailing impoundments is verified using dust collection and topsoil measurements. The forecast deposition patterns are compared to dust collected by inverted-disc samplers through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. Finally, the bioaccessibility of As and Pb were on samples collected at Iron King Mine Tailing was evaluated through chemical extractions using simulated the gastric and the lung fluids of the human body. Results obtained indicate that extractions using simulated gastric fluid lead to As concentrations one order of magnitude higher to those obtained with lung fluid. For Pb concentration the difference was greater than 2 orders of magnitude.
Degree ProgramGraduate College