College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Nankai University, Tianjin 300071, PR China.
Chemosphere. 2011 Oct;85(3):424-31. doi: 10.1016/j.chemosphere.2011.07.069. Epub 2011 Sep 3.
A 45-d Tenax extraction was used to evaluate the bioavailability of polybrominated diphenyl ethers (PBDEs) in three spiked sediments. The effect of aging on desorption kinetics of PBDEs was investigated by incubating one of the sediments for 7, 14, 30 and 60 d at room temperature. Desorption kinetics were well described by a three-compartment model. The fraction of very slow desorption (Fvs) contributed the most of the desorbed PBDEs from sediments. The total desorption amount of PBDEs decreased with the increase of total organic carbon in the sediments, suggesting that organic matter is an important factor controlling the partition of PBDEs in sediments. The total desorption amount of PBDEs decreased while log [(Fslow+Fvs)/Frap] increased with logKow of PBDE congeners, indicating that the bioavailability of PBDEs in sediment decreases with logKow of the congeners. As the residential time of PBDEs in the sediment increased from 7 to 60 d, Frap of individual PBDE congeners decreased gradually with simultaneous increase of Fvs. There was a good positive correlation between Frap and F6/F24, indicating that either 6 h or 24 h Tenax extraction could be a proxy for Frap and bioavailability. In general, the results in present study suggest that the bioavailability of nona- and deca-BDEs in sediment is very low due to their strong hydrophobicity and large molecular size.
采用 45 天 Tenax 萃取法评估了三种加标沉积物中多溴二苯醚（PBDEs）的生物可利用性。通过在室温下将其中一种沉积物孵育 7、14、30 和 60 天，研究了老化对 PBDEs 解吸动力学的影响。解吸动力学很好地用三组分模型来描述。非常缓慢解吸（Fvs）的分数对从沉积物中解吸的 PBDEs 贡献最大。随着沉积物中总有机碳的增加，PBDEs 的总解吸量减少，这表明有机物是控制 PBDEs 在沉积物中分配的重要因素。随着 PBDE 同系物的 Kowlog 的增加，PBDEs 在沉积物中的生物可利用性降低，同时总解吸量减少，而 [(Fslow+Fvs)/Frap] 的对数增加，这表明 PBDEs 在沉积物中的生物可利用性随着同系物 Kowlog 的增加而降低。随着 PBDEs 在沉积物中的居留时间从 7 天增加到 60 天，个别 PBDE 同系物的 Frap 逐渐降低，同时 Fvs 增加。Frap 与 F6/F24 之间存在良好的正相关关系，表明 6 小时或 24 小时 Tenax 萃取都可以作为 Frap 和生物可利用性的替代物。总的来说，本研究的结果表明，由于非和十溴二苯醚具有很强的疏水性和较大的分子尺寸，其在沉积物中的生物可利用性非常低。
