Vegetation successfully prevents oxidization of sulfide minerals in mine tailings.
The oxidization of metal sulfide in tailings causes acid mine drainage. However, it remains unclear whether vegetation prevents the oxidization of metal sulfides. The oxidization characteristics and microbial indices of the tailings in the presence of various plant species were investigated to explore the effects of vegetation on the oxidization of sulfide minerals in tailings. The pH, reducing sulfur, free iron oxides (Fed), chemical oxygen consumption (COC) and biological oxygen consumption (BOC) were measured. Key iron- and sulfur-oxidizing bacteria (Acidithiobacillus spp., Leptospirillum spp. and Thiobacillus spp.) were quantified using real-time PCR. The results indicate that vegetation growing on tailings can effectively prevent the oxidization of sulfide minerals in tailings. A higher pH and reducing-sulfur content and lower Fed were observed in the 0-30 cm depth interval in the presence of vegetation compared to bare tailings (BT). The COC gradually decreased with depth in all of the soil profiles; specifically, the COC rapidly decreased in the 10-20 cm interval in the presence of vegetation but gradually decreased in the BT profiles. Imperata cylindrica (IC) and Chrysopogon zizanoides (CZ) profiles contained the highest BOC in the 10-20 cm interval. The abundance of key iron- and sulfur-oxidizing bacteria in the vegetated tailings were significantly lower than in the BT; in particular, IC was associated with the lowest iron- and sulfur-oxidizing bacterial abundance. In conclusion, vegetation successfully prevented the oxidization of sulfide minerals in the tailings, and Imperata cylindrica is the most effective in reducing the number of iron- and sulfur-oxidizing bacteria and helped to prevent the oxidization of sulfide minerals in the long term.
School of Resources and Environmental Engineering, Anhui University, Hefei, Anhui, China.
Yang
Y
Li
School of Resources and Environmental Engineering, Anhui University, Hefei, Anhui, China. Electronic address: sunqingye@ahu.edu.cn.
Qingye
Q
Sun
School of Resources and Environmental Engineering, Anhui University, Hefei, Anhui, China.
Jing
J
Zhan
School of Resources and Environmental Engineering, Anhui University, Hefei, Anhui, China.
Yang
Y
Yang
School of Resources and Environmental Engineering, Anhui University, Hefei, Anhui, China.
Dan
D
Wang
D042763:Acidithiobacillus / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D002681:China; D049930:Chrysopogon / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000378:metabolism; D008670:Metals / Q000737:chemistry / Q000378:metabolism; D008903:Minerals / Q000737:chemistry / Q000378:metabolism; D008906:Mining; D010084:Oxidation-Reduction; D006109:Poaceae / Q000502:physiology*; D016133:Polymerase Chain Reaction; D013440:Sulfides / Q000737:chemistry* / Q000378:metabolism; D016999:Sulfur-Reducing Bacteria / Q000235:genetics / Q000378:metabolism
D008670:Metals; D008903:Minerals; D013440:Sulfides; D007501:Iron
Biological oxidization; Chemical oxidization; Mine tailings; Sulfur oxidization