Selenium speciation in coal ash spilled at the tennessee valley authority kingston site

Yu Ting Liu, Tsan Yao Chen, William Greer MacKebee, Laura Ruhl, Avner Vengosh, Heileen Hsu-Kim

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Selenium (Se) in coal ash spills poses a threat to adjacent ecosystems because of its potential to mobilize and bioaccumulate in aquatic organisms. Given that the mobility and bioavailability of Se is controlled by its valence states, we aimed to define Se speciation in coal ash solids and examine the relationships between Se speciation and the magnitude of its mobilization from coal ash. We used coal ash samples from the Tennessee Valley Authority (TVA)-Kingston fossil plant and the site of a coal ash spill that occurred in 2008 in Tennessee. Results of X-ray absorption spectroscopic analyses showed that Se in coal ash samples was a mixture of elemental Se0 and Se oxyanions. The amount of leachable Se increased with an increase of pH from 3 to 13. At the natural pH of coal ash samples (from pH 7.6 to 9.5), the leachable Se was comprised of Se oxyanions, mainly selenite. This was observed by both direct quantification of Se oxyanions in the leachate and the corresponding loss of Se oxyanions in the solid phase. At pH 12, however, the Se release appeared to derive from both desorption of Se oxyanions and oxidative dissolution of elemental Se0. Our results indicate that Se oxyanions are the most labile species; however, the magnitude of Se mobilization will increase if the waste material is subjected to alkaline conditions.

Original languageEnglish
Pages (from-to)14001-14009
Number of pages9
JournalEnvironmental Science & Technology
Volume47
Issue number24
DOIs
StatePublished - 17 Dec 2013
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry (all)
  • Environmental Chemistry

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