Acid mine drainage at the Bahia Gold Belt (Brazil): microbial isolation and characterization

• Published in: Environmental monitoring and assessment 2021-02, Vol.193 (2), p.60, Article 60
• Main Authors: Bernardez, Leticia A., de Oliveira, Luis Eduardo L., de Andrade Lima, Luiz Rogério P.
• Format: Article
• Language: English
• Subjects: Acid mine drainage; Acidithiobacillus; Aluminum; Archaea; Atmospheric Protection/Air Quality Control/Air Pollution; Bacterial leaching; Belts; Brazil; Clinochlore; Concentrates (ores); Copper; Copper ores; Copper sulfides; Drainage; Earth and Environmental Science; Ecology; Ecotoxicology; Environment; Environmental Management; Environmental Monitoring; Environmental science; Gold; Gravity; Groundwater; Iron constituents; Leaching; Major constituents; Mica; Microorganisms; Mine drainage; Mine tailings; Mine wastes; Minerals; Mining; Monitoring/Environmental Analysis; Muscovite; Oxidation; Pyrite; Silicon; Sulfides; Sulfur; Sulfur content; Sulphides; Sulphur; Surface water; Surface-groundwater relations; Tailings; Water pollution; Water purification
• ISSN: 0167-6369; 1573-2959
• DOI: 10.1007/s10661-021-08844-2

Acid mine drainage occurs due to the chemical and microbiological oxidation of sulfide minerals and can be a source of potentially toxic elements contamination of groundwater and surface water. The objective of this study was to identify microorganisms involved in sulfide oxidation in the tailings of a Bahia Gold Belt mine (Brazil). Samples of solids and water were collected at the mine tailings dam and characterized. The microorganisms were isolated after enrichment and subsequent purification. The major constituents of the tailings are Si, Fe, Al, S, and K. The sulfur content of the tailings is 0.98%. The major phases are quartz, muscovite, and clinochlore. Gravity concentrates of the tailings show several particles of pyrite, that is, the major sulfide phase. Molecular analysis identified the microorganisms isolated in the acid mine drainage process in this region. Five bacterium species were found: Acidithiobacillus spp., Acidithiobacillus ferrooxidans, Acidiphilium spp., Leptospirillum type II, and Sulfobacillus spp. No organisms of the archaea or eukaryote domains were found. The isolate was used in the bioleaching of copper sulfide ore, and the copper extraction was about 60% in 60 days for ground ore.