School of Biological Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, United Kingdom.
Appl Environ Microbiol. 2011 Dec;77(23):8201-8. doi: 10.1128/AEM.06155-11. Epub 2011 Sep 30.
Pyritic mine tailings (mineral waste generated by metal mining) pose significant risk to the environment as point sources of acidic, metal-rich effluents (acid mine drainage [AMD]). While the accelerated oxidative dissolution of pyrite and other sulfide minerals in tailings by acidophilic chemolithotrophic prokaryotes has been widely reported, other acidophiles (heterotrophic bacteria that catalyze the dissimilatory reduction of iron and sulfur) can reverse the reactions involved in AMD genesis, and these have been implicated in the "natural attenuation" of mine waters. We have investigated whether by manipulating microbial communities in tailings (inoculating with iron- and sulfur-reducing acidophilic bacteria and phototrophic acidophilic microalgae) it is possible to mitigate the impact of the acid-generating and metal-mobilizing chemolithotrophic prokaryotes that are indigenous to tailing deposits. Sixty tailings mesocosms were set up, using five different microbial inoculation variants, and analyzed at regular intervals for changes in physicochemical and microbiological parameters for up to 1 year. Differences between treatment protocols were most apparent between tailings that had been inoculated with acidophilic algae in addition to aerobic and anaerobic heterotrophic bacteria and those that had been inoculated with only pyrite-oxidizing chemolithotrophs; these differences included higher pH values, lower redox potentials, and smaller concentrations of soluble copper and zinc. The results suggest that empirical ecological engineering of tailing lagoons to promote the growth and activities of iron- and sulfate-reducing bacteria could minimize their risk of AMD production and that the heterotrophic populations could be sustained by facilitating the growth of microalgae to provide continuous inputs of organic carbon.
含黄铁矿的尾矿（金属采矿产生的矿物废物）是环境的重大风险源，因为它们是酸性、富含金属的废水（酸性矿山排水，AMD）的点源。虽然嗜酸化学自养原核生物加速了尾矿中黄铁矿和其他硫化物矿物的氧化溶解，但其他嗜酸菌（催化铁和硫异化还原的异养细菌）可以逆转 AMD 成因所涉及的反应，这些细菌被认为参与了矿山废水的“自然衰减”。我们研究了通过操纵尾矿中的微生物群落（接种铁和硫还原嗜酸细菌和光养嗜酸微藻）是否有可能减轻对生成酸和迁移金属的土著尾矿沉积物中化学自养原核生物的影响。使用五种不同的微生物接种变体设置了 60 个尾矿中规模，定期分析长达 1 年的物理化学和微生物参数变化。处理方案之间的差异在除了好氧和厌氧异养细菌外还接种了嗜酸藻类的尾矿与仅接种黄铁矿氧化化学自养生物的尾矿之间最为明显；这些差异包括更高的 pH 值、更低的氧化还原电位以及更小浓度的可溶性铜和锌。结果表明，通过经验生态工程对尾矿池进行改造以促进铁和硫酸盐还原细菌的生长和活性，可以最大限度地降低 AMD 产生的风险，并且可以通过促进微藻的生长为异养种群提供持续的有机碳输入来维持其生长。
