Yen J H, Liao W C, Chen W C, Wang Y S
Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.
J Hazard Mater. 2009 Jun 15;165(1-3):518-24. doi: 10.1016/j.jhazmat.2008.10.007. Epub 2008 Oct 14.
The degradation of flame retardant polybrominated diphenyl ethers (PBDE), including tetra-brominated diphenyl ether (BDE-47), penta-brominated diphenyl ether (BDE-99 and -100), and hexa-brominated diphenyl ether (BDE-153 and -154), by anaerobic bacterial mixed cultures isolated from river sediment was investigated. The effects of PBDEs on changes of anaerobic bacterial community in sediment culture were also studied. Sediments were collected from Er-Jen River and Nan-Kan River basins, which were both heavily polluted rivers in Taiwan, and bacteria from the sediment samples were enriched before the experiment was conducted. Into the anaerobic bacterial mixed cultures, 0.1 microg/mL of PBDEs was added followed by incubation under 30 degrees C for 70 days. Residues of PBDE were determined by gas chromatography with electron capture detector (GC-ECD), and the changes of bacterial community were analyzed by denaturing gradient gel electrophoresis (DGGE). Less than 20% of PBDEs were degraded after 70 days of incubation in all samples except for BDE-47 from the Nan-Kan River sediment. In that culture, BDE-47 was found to have notably degraded. In particular, after 42 days of incubation; BDE-47 was degraded, suddenly and sharply, to a negligible level on Day 70, and the result was confirmed by a repeated experiment. An interesting result was that although BDE-47 was degraded fast in the Nan-Kan River sediment, the bacterial communities did not shift significantly as we had speculated at Day 70. From UPGMA dendrograms, PBDEs changed the composition of bacterial communities, and the extents varied with the variety of PBDE congeners. By the amendment with BDE-153 or -154, bacterial communities would be changed immediately and irreversibly throughout the rest of the incubation period. No significant difference in degradation of PBDEs was observed between sediment bacteria from Er-Jen River and Nan-Kan River. However, the results verified the persistence of PBDEs in the environment.
研究了从河流沉积物中分离出的厌氧细菌混合培养物对阻燃剂多溴二苯醚（PBDE）的降解情况，其中包括四溴二苯醚（BDE - 47）、五溴二苯醚（BDE - 99和 - 100）以及六溴二苯醚（BDE - 153和 - 154）。还研究了多溴二苯醚对沉积物培养中厌氧细菌群落变化的影响。沉积物取自台湾受严重污染的二仁溪流域和南竿溪流域，在实验进行前对沉积物样本中的细菌进行了富集培养。向厌氧细菌混合培养物中添加0.1微克/毫升的多溴二苯醚，然后在30℃下孵育70天。采用带电子捕获检测器的气相色谱法（GC - ECD）测定多溴二苯醚的残留量，通过变性梯度凝胶电泳（DGGE）分析细菌群落的变化。除了南竿溪沉积物中的BDE - 47外，所有样本在孵育70天后，多溴二苯醚的降解率均低于20%。在该培养物中，发现BDE - 47有明显降解。特别是在孵育42天后，BDE - 47突然急剧降解，到第70天时降至可忽略不计的水平，重复实验证实了该结果。一个有趣的结果是，尽管BDE - 47在南竿溪沉积物中降解迅速，但在第70天时细菌群落并未如我们推测的那样发生显著变化。从UPGMA聚类图来看，多溴二苯醚改变了细菌群落的组成，且变化程度因多溴二苯醚同系物的种类而异。通过添加BDE - 153或 - 154，在整个剩余孵育期内细菌群落会立即且不可逆地发生变化。二仁溪和南竿溪沉积物细菌对多溴二苯醚的降解未观察到显著差异。然而，结果证实了多溴二苯醚在环境中的持久性。
