Sulfate-reducing bacteria (SRB) mediated carbonate dissolution and arsenic release: Behavior and mechanisms

Yu Jiang; Xubo Gao; Xinwen Yang; Peili Gong; Zhendong Pan; Ling Yi; Siyuan Ma; Chengcheng Li; Shuqiong Kong; Yanxin Wang

doi:10.1016/j.scitotenv.2024.172572

Sulfate-reducing bacteria (SRB) mediated carbonate dissolution and arsenic release: Behavior and mechanisms

Sci Total Environ. 2024 Apr 18:929:172572. doi: 10.1016/j.scitotenv.2024.172572. Online ahead of print.

Authors

Yu Jiang¹, Xubo Gao², Xinwen Yang¹, Peili Gong¹, Zhendong Pan¹, Ling Yi¹, Siyuan Ma¹, Chengcheng Li¹, Shuqiong Kong¹, Yanxin Wang¹

Affiliations

¹ State Key Laboratory of Biogeology and Environmental Geology and School of Environmental Studies, China University of Geosciences, 430074 Wuhan, Hubei, China.
² State Key Laboratory of Biogeology and Environmental Geology and School of Environmental Studies, China University of Geosciences, 430074 Wuhan, Hubei, China; Institute of Karst Geology, Chinese Academy of Geological Sciences, 50 Qixing Road, Guilin, Guangxi 541004, China. Electronic address: xubo.gao.cug@gmail.com.

PMID: 38641113
DOI: 10.1016/j.scitotenv.2024.172572

Abstract

Carbonate bound arsenic act as an important reservoir for arsenic (As) in nature aquifers. Sulfate-reducing bacteria (SRB), one of the dominant bacterial species in reductive groundwater, profoundly affects the biogeochemical cycling of As. However, whether and how SRB act on the migration and transformation of carbonate bound arsenic remains to be elucidated. Batch culture experiment was employed using filed collected arsenic bearing calcite to investigate the release and species transformation of As by SRB. We found that arsenic in the carbonate samples mostly exist as inorganic As(V) (93.92 %) and As(III). The present of SRB significantly facilitated arsenic release from carbonates with a maximum of 22.3 μg/L. The main release mechanisms of As by SRB include 1) calcite dissolution and the liberate of arsenic in calcite lattices, and 2) the break of H-bonds frees arsenic absorbed on carbonate surface. A redistribution of arsenic during culture incubation took place which may due to the precipitation of As₂S_x or secondary FeAl minerals. To our best knowledge, it is the first experimental study focusing on the release of carbonate bound arsenic by SRB. This study provides new insights into the fate and transport of arsenic mediated by microorganism within high arsenic groundwater-sediment system.

Keywords: Arsenic; Arsenic rich groundwater; Carbonate; Sulfate-reducing bacteria.