Influence of Sulfate-Reducing Bacteria on the Mobility of Arsenic in Soils an "In Vitro" Study

Abstract:

Ouro Preto/MG/Brazil soils are rich in arsenic containing minerals that once solubilized may contaminate water or food. Arsenic (As) is toxic if ingested or inhaled. Microorganisms and organic matter plays an important role in the dynamics of As in soils and sediments affecting its mobilization. Aims: to study the mobility of arsenic in the presence of organic matter and sulfur reducing bacteria (SRB) and also to obtain some As resistant bacterial cultures. Materials: Soil samples were collected from abandoned gold mines named Old Mine, Chico Rei and Santa Rita. As content in solid samples were in a range of 465 to 1829 mg Kg^-1. Soil samples (5 g) were mixed with 35 ml of 2.5 M, CaCl₂, stirred (5 min) and allowed to rest at 21.0°C for 1, 30, 60, 90 and 120 days. Other set of experiments were prepared following the previous procedure with some modifications: (i) group 1, flasks with bacterial inoculum (4 ml) from an enrichment of 5 g of soil and 45 ml of liquid medium B Postgate, pH 7.0, incubated at 35°C under anaerobic conditions; (ii) group 2, flasks with (5 g) of organic matter with As (III) adsorptive capacity (powdered chicken feathers - PCF), and (iii) group 3, flasks containing bacterial inoculum and organic matter. Results: As solubility was inversely proportional to time and depends on Fe and Mn contents. The influence of microorganisms on As immobilization was more relevant than the presence of organic matter. Surprisingly, in some cases, As solubility enhanced in the presence of PCF besides its As adsorptive capacity. One microbial consortium adapted to the culturing at pH 5.0 was obtained and this is an interesting feature considering the acid pH of the studied arsenic soils. Indigenous bacteria phenotypically similar to SRB may contribute to As immobilization in natural or impacted environment.

• Periodical: Advanced Materials Research (Volume 825)
• Pages: 548-551
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.825.548
• Online since: October 2013
• Authors: Lillian Rabelo Lopes, Mônica Cristina Teixeira
• Keywords: Abandoned Mines, Anaerobic Microorganisms, Arsenic, Iron, Manganese, Sulfate-Reducing Bacteria (SRB)

References

[1] S. Tsai, S. Singh, W. Chen, Arsenic metabolism by microbes in nature and the impact on arsenic remediation. Current Opinion in Biotechnology, 20 (2009) 659–667.

DOI: 10.1016/j.copbio.2009.09.013

[2] Information on <http: /www. comitepcj. sp. gov. br/download/Portaria_MS_1469-00. pdf>.

[3] C. M. Reynolds, H. D. Skipper, Bioremediation of contaminated soil, in: D. M. Sylvia et al. Principles and applications of soil microbiology. Pearson Prentice Hall, New Jersey, 2005, pp.536-561.

[4] R. Turpeinen, M. Pantsar-Kallio, M. Häggblom, T. Kairesalo, Influence of microbes on the mobilization, toxicity and biomethylation of arsenic in soil. The Science of the Total Environment, 236 (1999) 173-180.

DOI: 10.1016/s0048-9697(99)00269-7

[5] J. W. V. Mello1, W. R. Roy, J. L. Talbott, J. W. Stucki, Mineralogy and Arsenic Mobility in Arsenic-rich Brazilian Soils and Sediments. JSS – J Soils & Sediments, 6 (2006) 9–19.

DOI: 10.1065/jss2005.09.144

[6] M.C. Teixeira, V.S.T. Ciminelli. Development of a biosorbent for arsenite: Structural modeling based on X-Ray spectroscopy. Environmental Science & Technology, vol. 39 (2005) 895-900.

DOI: 10.1021/es049513m

[7] K. Lizama, T.D. Fletcher, G. Sun. Removal processes for arsenic in constructed wetlands. Chemosphere, 84 (2011) 1032–1043.

DOI: 10.1016/j.chemosphere.2011.04.022