Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, China.
School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China.
Int J Environ Res Public Health. 2022 Dec 17;19(24):16987. doi: 10.3390/ijerph192416987.
Microbes have important impacts on the mobilization of arsenic in groundwater. To study the effects of sulfide on As(V) bioreduction in sulfidic groundwater, Citrobacter sp. JH012-1 isolated from sediments in the Jianghan Plain was used in a microcosm experiment. The results showed that sulfide significantly enhanced As(V) bioreduction as an additional electron donor. The reduction rates of As(V) were 21.8%, 34.5%, 73.6% and 85.9% under 0, 15, 75 and 150 µM sulfide inputting, respectively. The main products of As(V) bioreduction were thioarsenite and orpiment and the concentration of thioarsenite reached to 5.5 and 7.1 µM in the solution with the initial 75 and 150 µM sulfide, respectively. However, under 0 and 15 µM sulfide inputting, the dominant product was arsenite with no thioarsenite accumulation. The decrease in pH enhanced the bioreduction of As(V) and promoted the formation of thioarsenite and orpiment. In addition, the percentage of thioarsenite in total arsenic decreased with the decrease in the ratio of sulfur to arsenic, indicating that the formation of thioarsenite was limited by the concentration of initial sulfide. Therefore, the presence of sulfide had a significant effect on the transformation of arsenic in groundwater. This study provides new insights into the bioreduction of As(V) and the formation of thioarsenite in sulfidic groundwater.
微生物对地下水砷的迁移具有重要影响。为了研究硫化物对含硫地下水中 As(V)生物还原的影响，本研究从江汉平原沉积物中分离得到一株柠檬酸杆菌（Citrobacter sp.）JH012-1，并将其应用于微宇宙实验中。结果表明，硫化物作为额外的电子供体可显著促进 As(V)的生物还原。在 0、15、75 和 150 μM 硫化物输入条件下，As(V)的还原速率分别为 21.8%、34.5%、73.6%和 85.9%。As(V)生物还原的主要产物为硫代砷酸盐和雄黄，在初始 75 和 150 μM 硫化物条件下，溶液中硫代砷酸盐的浓度分别达到 5.5 和 7.1 μM。然而，在 0 和 15 μM 硫化物输入条件下，优势产物为砷酸盐，没有硫代砷酸盐的积累。pH 值的降低促进了 As(V)的生物还原，并促进了硫代砷酸盐和雄黄的形成。此外，硫代砷酸盐在总砷中的百分比随着硫砷比的降低而降低，表明硫代砷酸盐的形成受到初始硫化物浓度的限制。因此，硫化物的存在对地下水砷的转化有显著影响。本研究为含硫地下水 As(V)生物还原和硫代砷酸盐的形成提供了新的见解。
Zotero 插件
