Water Resources Division, U.S. Geological Survey, 345 Middlefield Road, Menlo Park, California 94025, and Tiburon Center, San Francisco State University, Tiburon, California 94920.
Appl Environ Microbiol. 1989 Sep;55(9):2333-43. doi: 10.1128/aem.55.9.2333-2343.1989.
Interstitial water profiles of SeO(4), SeO(3), SO(4), and Cl in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO(4) occurred under anaerobic conditions, was more rapid with H(2) or acetate, and was inhibited by O(2), NO(3), MnO(2), or autoclaving but not by SO(4) or FeOOH. Oxidation of acetate in sediments could be coupled to selenate but not to molybdate. Reduction of selenate to elemental selenium was determined to be the mechanism for loss from solution. Selenate reduction was inhibited by tungstate and chromate but not by molybdate. A small quantity of the elemental selenium precipitated into sediments from solution could be resolublized by oxidation with either nitrate or FeOOH, but not with MnO(2). A bacterium isolated from estuarine sediments demonstrated selenate-dependent growth on acetate, forming elemental selenium and carbon dioxide as respiratory end products. These results indicate that dissimilatory selenate reduction to elemental selenium is the major sink for selenium oxyanions in anoxic sediments. In addition, they suggest application as a treatment process for removing selenium oxyanions from wastewaters and also offer an explanation for the presence of selenite in oxic waters.
缺氧沉积物中 SeO(4)、SeO(3)、SO(4) 和 Cl 的间隙水分布表明，硒氧阴离子的去除是一种与硫酸盐还原无关的近表面过程。在沉积物泥浆实验中，在厌氧条件下硒酸盐完全被还原去除，在 H(2)或醋酸盐存在下更快，并且被 O(2)、NO(3)、MnO(2)或高压灭菌抑制，但不受 SO(4)或 FeOOH 抑制。沉积物中醋酸盐的氧化可以与硒酸盐偶联，但不能与钼酸盐偶联。从溶液中损失的机制被确定为硒酸盐还原为元素硒。钨酸盐和重铬酸盐抑制硒酸盐还原，但钼酸盐不抑制。溶液中沉淀的少量元素硒可以通过硝酸盐或 FeOOH 氧化重新溶解，但不能通过 MnO(2)氧化。从河口沉积物中分离出的一种细菌在醋酸盐上表现出依赖于硒酸盐的生长，形成元素硒和二氧化碳作为呼吸终产物。这些结果表明，异化硒酸盐还原为元素硒是缺氧沉积物中硒氧阴离子的主要汇。此外，它们还可以作为从废水中去除硒氧阴离子的处理过程，也可以解释在好氧水中存在亚硒酸盐的原因。
