Geochemistry, Mineralogy and Microbiology of Molybdenum in Mining-Affected Environments

• Published in: Minerals (Basel) 2018-02, Vol.8 (2), p.42
• Main Authors: Frascoli, Francesca, Hudson-Edwards, Karen
• Format: Article
• Language: English
• Subjects: Bacteria; Bioavailability; Bioremediation; Contaminated land; Contamination; Cycles; Environmental management; Exploitation; Geochemistry; Human behavior; Industrial applications; Iron; Jarosite; Land pollution; Microbiology; Microorganisms; Mine tailings; Mine wastes; Mineral deposits; Mineralogy; Minerals; Mining; Molybdenum; Oxidation; Sediments; Soil; Soil contamination; Soil pollution; Soil water; Sulfides; Sulphides; Wastes; Water pollution
• ISSN: 2075-163X; 2075-163X
• DOI: 10.3390/min8020042

Molybdenum is an essential element for life, with growing production due to a constantly expanding variety of industrial applications. The potentially harmful effects of Mo on the environment, and on human and ecosystem health, require knowledge of Mo behavior in mining-affected environments. Mo is usually present in trace amounts in ore deposits, but mining exploitation can lead to wastes with very high Mo concentrations (up to 4000 mg/kg Mo for tailings), as well as soil, sediments and water contamination in surrounding areas. In mine wastes, molybdenum is liberated from sulfide mineral oxidation and can be sorbed onto secondary Fe(III)-minerals surfaces (jarosite, schwertmannite, ferrihydrite) at moderately acidic waters, or taken up in secondary minerals such as powellite and wulfenite at neutral to alkaline pH. To date, no Mo-metabolising bacteria have been isolated from mine wastes. However, laboratory and in-situ experiments in other types of contaminated land have suggested that several Mo-reducing and -oxidising bacteria may be involved in the cycling of Mo in and from mine wastes, with good potential for bioremediation. Overall, a general lack of data is highlighted, emphasizing the need for further research on the contamination, geochemistry, bio-availability and microbial cycling of Mo in mining-affected environments to improve environmental management and remediation actions.