Research
| Title： | Excessive bivalent manganese promotes the arsenate-respiring bacteria-mediated reduction and mobilization of arsenic from contaminated vegetable field soils |
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| First author： | Xu, Yifan; Shi, Wanxia; Wu, Weiwei; Zuo, Yanxia; Chen, Xiaoming; Zeng, Xian-Chun |
| Journal： | JOURNAL OF SOILS AND SEDIMENTS |
| Years： | 2022 |
| DOI： | 10.1007/s11368-022-03275-z |
| Abstract： | Purpose Dissimilatory arsenate[As(V)]-respiring prokaryotes (DARPs) were consider to be the major player driving the reductive mobilization of As from solid phase. Mn(II) commonly coexists with DARPs in the environment. However, little is known about how Mn(II) affects the DARPs-mediated reductive mobilization of arsenic so far. This work aimed to address this issue. Method Three As-contaminated samples were collected from the arsenic-contaminated shallow soils. We examined the diversity and activity of the DARP population in the soils, and detected how Mn(II) affected the DARPs-mediated reductive mobilization. We also investigated how Mn(II) affected the arrA gene abundances and bacterial As(V)-respiring activities. Results We observed that a unique diversity of genes encoding As(V)-respiratory reductase were widely present in the shallow soils. The soils possessed high As(V)-respiring activities by using multiple electron donors. Microcosm assays indicated that compared to the microcosms without excessive Mn(II), addition of additional 10.0 mM Mn(II) to the microcosms led to 140.2%, 121.3%, and 257.8% increases of the microbial community-mediated As(III) release from the three soil samples. To further confirm this finding, a novel DARP, Bacillus sp. RM19 was ioslated from the samples. Microcosm assays with this cultivable DARP showed that the presence of additional 10.0 mM Mn(II) resulted in a 23.9% increase of the RM19-catalyzed As(III) release from the soils. Taken together, Mn(II) greatly enhances the As(V)-respiring prokaryotes-catalyzed reductive mobilization of As from soils. Conclusion This work provided new knowledge about the relationship between the biogeochemical cycles of As and Mn, and gained a new insight into the mechanism for the dynamic changes of As concentrations in contaminated groundwater. |
