Microbially-mediated arsenic release from arsenic-laden water treatment residuals under anaerobic landfill conditions with varying anion concentrations is not incorporated into current regulatory leaching tests. In this study, arsenic-laden iron-oxide adsorbents were incubated with the arsenic and sulfate reducing bacteria Bacillus benzoevorans and the iron and arsenic reducing bacteria Shewanella putrefaciens in synthetic landfill leachate. Concentrations of phosphate, bicarbonate, sulfate and silicate were allowed to vary across ranges measured in landfill systems. We discovered phosphate promoted fast As release by ion exchange followed by fast As readsorption during iron-sulfide formation. Arsenic was slowly released from the sulfides during the remainder of the incubation. Bicarbonate stimulated As release by increasing As bioreduction. Sulfate and silicate didn't alter As and S bioreduction, but did inhibit Fe bioreduction resulting in different As release for the two bacteria strains. Results demonstrate anions should be considered when assessing arsenic remobilization and associated environmental and health effects.

Influence of anions on microbially-mediated arsenic release from spent iron adsorbents under anaerobic landfill conditions

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.