Removal of selenium from groundwater was documented during injection of acetate into a uranium‐contaminated aquifer near Rifle, Colorado (USA). Bioreduction of aqueous selenium to its elemental form (Se⁰) concentrated it within mineralized biofilms affixed to tubing used to circulate acetate‐amended groundwater. Scanning and transmission electron microscopy revealed close association between Se⁰ precipitates and cell surfaces, with Se⁰ aggregates having a diameter of 50–60 nm. Accumulation of Se⁰ within biofilms occurred over a three‐week interval at a rate of c. 9 mg Se⁰m⁻² tubing day⁻¹. Removal was inferred to result from the activity of a mixed microbial community within the biofilms capable of coupling acetate oxidation to the reduction of oxygen, nitrate and selenate. Phylogenetic analysis of the biofilm revealed a community dominated by strains of Dechloromonas sp. and Thauera sp., with isolates exhibiting genetic similarity to the latter known to reduce selenate to Se⁰. Enrichment cultures of selenate‐respiring microorganisms were readily established using Rifle site groundwater and acetate, with cultures dominated by strains closely related to D. aromatica (96–99% similarity). Predominance of Dechloromonas sp. in recovered biofilms and enrichments suggests this microorganism may play a role in the removal of selenium oxyanions present in Se‐impacted groundwaters and sediments.

中文翻译：

---

铀污染的含水层中硒生物还原的现场证据。

在向美国科罗拉多州的莱夫勒附近的铀污染的含水层中注入乙酸盐的过程中，记录了地下水中硒的去除。硒水溶液的生物还原成元素形式（Se ⁰）会将其浓缩在附着在用于循环醋酸盐修正的地下水的管道上的矿化生物膜中。扫描和透射电子显微镜显示，Se ⁰沉淀物与细胞表面之间有紧密的联系，Se ⁰聚集体的直径为50-60 nm。在三周的时间间隔内，生物膜中硒^0的积累速率为c。9 mg Se ⁰ m ^-2油管日^-1。推断去除是由于能够将乙酸盐氧化与氧，硝酸盐和硒酸盐的还原偶联的生物膜内混合微生物群落的活性所致。对生物膜的系统发育分析表明，该群落以Dechloromonas sp。菌株为主。和Thauera sp。，其分离物表现出与后者的遗传相似性，已知后者将硒酸还原为Se ⁰。使用步枪现场的地下水和醋酸盐可以很容易地建立硒酸呼吸微生物的富集培养，其培养以与芳族D.aromatica（96-99％相似）密切相关的菌株为主。十氯单胞菌的优势sp。回收的生物膜和富集物中的微生物表明，该微生物可能在去除硒影响的地下水和沉积物中存在的硒氧阴离子方面发挥了作用。