Dissolution and final fate of arsenic associated with gypsum, calcite, and ferrihydrite: Influence of microbial reduction of As(V), sulfate, and Fe(III)

Erika E. Rios-Valenciana, Roberto Briones-Gallardo, Luis F. Chazaro-Ruiz, Nguyen E. Lopez-Lozano, Reyes Sierra-Alvarez, Lourdes B. Celis

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Several studies have demonstrated that gypsum (CaSO4·2H2O) and calcite (CaCO3) can be important hosts of arsenic in contaminated hydrogeological systems. However, the extent to which microbial reducing processes contribute to the dissolution and transformation of carbonate and sulfate minerals and, thereby, to arsenic mobilization is poorly understood. These processes are likely to have a strong impact on arsenic mobility in iron-poor environments and in reducing aquifers where iron oxyhydroxides become unstable. Anoxic batch bioassays with arsenate (As(V)) coprecipitated with calcite, gypsum, or ferrihydrite (Fe(OH)3) were conducted in the presence of sulfate or molybdate to examine the impact of bioprocesses (i.e. As(V), sulfate, and Fe(III)-reduction) on arsenic dissolution, speciation, and eventual remineralization. Microbial reduction of As(V)-bearing calcite caused an important dissolution of arsenite, As(III), which remained in solution up to the end of the experiment (30 days). The reduction of As(V) from gypsum-As(V) also led to the release of As(III), which was subsequently remineralized, possibly as arsenic sulfides. The presence of sulfate triggered arsenic dissolution in the bioassays with ferrihydrite-As(V). This study showed that although gypsum and calcite have a lower capacity to bind arsenic, compared to iron oxides, they can play a critical role in the biogeochemical cycle of arsenic in natural calcareous and gypsiferous systems depleted of iron since they can be a source of electron acceptors for reducing bioprocesses.

Original languageEnglish (US)
Article number124823
JournalChemosphere
Volume239
DOIs
StatePublished - Jan 2020

Keywords

  • Arsenate
  • Biogeochemistry
  • Bioprocesses
  • Mobilization
  • Remineralization
  • Sulfide

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Chemistry(all)
  • Pollution
  • Health, Toxicology and Mutagenesis

Fingerprint Dive into the research topics of 'Dissolution and final fate of arsenic associated with gypsum, calcite, and ferrihydrite: Influence of microbial reduction of As(V), sulfate, and Fe(III)'. Together they form a unique fingerprint.

  • Cite this