Sub-Department of Environmental Technology, Wageningen University, 6700 EV Wageningen, The Netherlands.
Environ Sci Technol. 2011 Feb 1;45(3):1067-73. doi: 10.1021/es1022619. Epub 2010 Dec 23.
In this study we evaluate the potential of anaerobic granular sludge as an inoculum for the bioremediation of selenium-contaminated waters using species-specific analytical methods. Solid species formed by microbial reduction were investigated using X-ray absorption near-edge structure (XANES) spectroscopy at the selenium K-edge. Furthermore, dissolved selenium species were specifically determined by ion chromatography (IC) and solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS). Least-squares linear combination of the XANES spectra for samples incubated with the highest selenate/selenite concentrations (10(-3) M) show the predominance of elemental selenium and a Se(-I) selenide, such as ferroselite, the thermodynamically most stable iron selenide. In contrast, elemental selenium and Se(-II) selenides are the main species detected at the lower selenate/selenite concentrations. In each repeated fed batch incubation, most aqueous selenite anions were converted into solid selenium species, regardless of the type of electron donor used (acetate or H(2)/CO(2)) and the selenium concentration applied. On the other hand, at higher concentrations of selenate (10(-4) and 10(-3) M), significant amounts of the oxyanion remained unconverted after consecutive incubations. SPME-GC-MS demonstrated selenium alkylation with both electron donors investigated, as dimethyl selenide (DMSe) and dimethyl diselenide (DMDSe). Selenite was even more alkylated in the presence of H(2)/CO(2) (maximum 2156 μg of Se/L of DMSe + DMDSe) as compared to acetate (maximum 50 μg of Se/L). In contrast, selenate was less alkylated using both electron donors (maximum 166 and 3 μg of Se/L, respectively). The high alkylation potential for selenite limits its bioremediation in selenium laden waters involving H(2)/CO(2) as the electron donor despite the fact that nontoxic elemental selenium and thermodynamically stable metal selenide species are formed.
在这项研究中，我们使用特定的分析方法评估了厌氧颗粒污泥作为生物修复受硒污染水的接种物的潜力。使用 X 射线吸收近边结构 (XANES) 光谱在硒 K 边对微生物还原形成的固相物种进行了研究。此外，通过离子色谱 (IC) 和固相微萃取气相色谱-质谱联用 (SPME-GC-MS) 专门测定了溶解的硒物种。对用最高硒酸盐/亚硒酸盐浓度 (10(-3) M) 孵育的样品的 XANES 光谱进行最小二乘线性组合表明，主要存在元素硒和热力学上最稳定的铁硒化物 ferroselite。相比之下，在较低的硒酸盐/亚硒酸盐浓度下，主要检测到元素硒和 Se(-II) 硒化物。在每个重复的进料批处理孵育中，无论使用的电子供体类型 (乙酸盐或 H(2)/CO(2)) 和应用的硒浓度如何，大多数水溶液中的亚硒酸盐阴离子都转化为固相硒化物。另一方面，在较高的硒酸盐浓度 (10(-4) 和 10(-3) M) 下，连续孵育后，仍有大量含氧阴离子未转化。SPME-GC-MS 证明了两种所研究的电子供体的硒烷基化，如二甲基硒 (DMSe) 和二甲基二硒 (DMDSe)。与乙酸盐相比，在 H(2)/CO(2) 存在下，亚硒酸盐的烷基化程度更高（最大 2156 μg/L 的 DMSe + DMDSe）。相反，使用两种电子供体时，硒酸盐的烷基化程度较低（分别为最大 166 和 3 μg/L）。尽管形成了无毒的元素硒和热力学稳定的金属硒化物，但由于亚硒酸盐的高烷基化潜力限制了其在涉及 H(2)/CO(2) 作为电子供体的含硒水中的生物修复。
