Arsenic release by indigenous bacteria Bacillus cereus from aquifer sediments at Datong Basin, northern China

Abstract

Endemic arsenic poisoning due to long-term drinking of high arsenic groundwater has been reported in Datong Basin, northern China. To investigate the effects of microbial activities on arsenic mobilization in contaminated aquifers, Bacillus cereus (B. cereus) isolated from high arsenic aquifer sediments of the basin was used in our microcosm experiments. The arsenic concentration in the treatment with both bacteria and sodium citrate or glucose had a rapid increase in the first 18 d, and then, it declined. Supplemented with bacteria only, the concentration could increase on the second day. By contrast, the arsenic concentration in the treatment supplemented with sodium citrate or glucose was kept very low. These results indicate that bacterial activities promoted the release of arsenic in the sediments. Bacterial activities also influenced other geochemical parameters of the aqueous phase, such as pH, Eh, and the concentrations of dissolved Fe, Mn, and Al that are important controls on arsenic release. The removal of Fe, Mn, and Al from sediment samples was observed with the presence of B. cereus. The effects of microbial activities on Fe, Mn, and Al release were nearly the same as those on As mobilization. The pH values of the treatments inoculated with bacteria were lower than those without bacteria, still at alkaline levels. With the decrease of Eh values in treatments inoculated with bacteria, the microcosms became more reducing and are thus favorable for arsenic release.

Arsenate reduction and mobilization in the presence of indigenous aerobic bacteria obtained from high arsenic aquifers of the Hetao basin, Inner Mongolia

“…At the end of incubations, dissolved As concentration generally kept constant, demonstrating that the release of As was not obvious due to the limited bacterial activity (2.0e3.5 nmol/L ATP). It showed that the activity of bacteria had a significant effect on the release of As from the sediment (Xie et al, 2011).…”

Response of growth and superoxide dismutase to enhanced arsenic in two Bacillus species

“…The organisms were cultivated in nutrient broth medium (1 % peptone, 0.3 % beef extract, and 0.5 % sodium chloride) at 25 ± 1°C in darkness (Xie et al 2011) to middle exponential phase for the following experiments.…”

“…In addition, more and more studies demonstrated that microorganisms play a significant role in geochemical behaviour of arsenic (Bachate et al 2009;Duan et al 2009;Macur et al 2001;Wang et al 2010;Xie and Wang 2009;Xie et al 2009aXie et al , 2011. As(III) can be oxidized to As(V) by chemoautotrophic arsenite oxidizer and heterotrophic arsenite oxidizer, or As(V) can be reduced to As(III) by dissimilatory arsenate-respiring prokaryote (Oremland and Stolz 2003;Sohrin et al 1997).…”

“…Some Bacillus species by using arsenic as terminal electron acceptors can even grow in areas with high As level such as arsenic polluted soil , high arsenic shallow aquifers (Xie et al 2011), as well as treatment plant waste (Velásquez and Dussan 2009).…”

Molecular and taxonomic characterization of arsenic (As) transforming Bacillus sp. strain IIIJ3–1 isolated from As-contaminated groundwater of Brahmaputra river basin, India

“…In general, presence of Bacillus spp. in Ascontaminated groundwater of Bengal basin and other alluvial aquifers as well in various polluted environment and their As transformation abilities have been well documented [17,[42][43][44][45]. Dissimilatory reduction of As 5+ by Bacillus spp.…”