Microbial bioavailability of 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) in natural sediments from major rivers of China.
Microbial bioavailability of 2,2',4,4'-Tetrabromodiphenyl ether (BDE-47) in natural sediments from major rivers of China.
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DOI：
10.1016/j.chemosphere.2016.03.050
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发表时间：
2016-06
期刊：
影响因子：
8.8
通讯作者：
B. Zhu;X. Xia;Shan Wu;Xiao-xia Lu;X. Yin
中科院分区：
文献类型：
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作者：
B. Zhu;X. Xia;Shan Wu;Xiao-xia Lu;X. Yin
微生物降解在消除环境中的多溴联苯醚（PBDEs）方面发挥着至关重要的作用。然而，人们对水生沉积物中多溴二苯醚的微生物生物利用度还没有很好的了解。研究了厌氧条件下，中国6条河流沉积物中多溴联苯醚（PBDE）的典型同系物2，2 ′，4，4 ′-四溴二苯醚（BDE-47）对PBDE降解菌的生物有效性。6个沉积物样品中黑碳（BC）和总有机碳（TOC）的含量分别为0.025%~ 0.30%和0.03%~ 3.38%。BDE-47在各种沉积物中的解吸符合一级三室解吸模型。沉积物中BDE-47在各解吸时间段的解吸分数与BC含量呈显著负相关（p< 0.01）。在沉积物中，微生物对BDE-47的厌氧脱溴经历了一个逐步脱溴途径，主要生成三种低溴同系物（BDE-28、-17和-4）。厌氧培养120 d后，不同沉积物中BDE-47的微生物脱溴率为4.21%~ 7.89%，且与沉积物中BC含量呈显著负相关（p< 0.01）。BDE-47的解吸率和微生物脱溴率与沉积物中TOC含量的相关性较弱（p> 0.05）。此外，在前20 d培养后，沉积物中BDE-47的解吸量与其微生物脱溴率（p< 0.01）以及三种低溴化产物的水平（p< 0.05）均呈显著正相关。这项研究表明，BDE-47对厌氧河流沉积物中微生物的生物利用度主要受沉积物BC含量的影响，BC控制着沉积物中BDE-47的解吸分数。
Microbial degradation plays a crucial role in eliminating polybrominated diphenyl ethers (PBDEs) in environments. However, the microbial bioavailability of PBDEs in aquatic sediments is not well understood. In this work, the bioavailability of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), a typical PBDE congener, to PBDE-degrading microorganisms in natural sediments from six Chinese rivers under anaerobic conditions was investigated. The contents of black carbon (BC) and total organic carbon (TOC) in the six sediment samples were in the range of 0.025%–0.30% and 0.03%–3.38%, respectively. BDE-47 desorption from various sediments was fitted well with the first-order three-compartment desorption model. The desorbing fraction of sediment-associated BDE-47 at each desorption time interval exhibited a significant negative correlation with the BC content (p< 0.01). In the sediments, the anaerobic debromination of BDE-47 by microorganisms underwent a stepwise debromination pathway generating mainly three lower brominated congeners (BDE-28, -17 and −4). The microbial debromination ratio of BDE-47 ranged from 4.21% to 7.89% in various sediments after 120 d incubation anaerobically, and it negatively correlated with the content of sediment BC significantly (p< 0.01). However, the desorbing fraction and microbial debromination ratio of BDE-47 only showed weak correlations with the TOC content in sediments (p> 0.05). Furthermore, there was a significant positive correlation of desorbing fraction of BDE-47 from sediments with its microbial debromination ratio (p< 0.01) as well as with the level of its three lower brominated products (p< 0.05) after the first 20 d incubation. This study suggests that the BDE-47 bioavailability to microorganisms in anaerobic river sediments is mainly influenced by the content of sediment BC which controls the desorbing fraction of sediment-associated BDE-47.