State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, China.
Chemosphere. 2010 Mar;78(11):1329-36. doi: 10.1016/j.chemosphere.2010.01.007. Epub 2010 Jan 29.
Carbonaceous sorbents including black carbon (BC) and carbon nanotubes have attracted research attention around the world because of their effects on bioavailability of hydrophobic organic compounds (HOCs) in sediments and soils. In this research, (14)C-labeled and unlabeled phenanthrene were spiked into three artificial sediments: (i) a sediment sample without amorphous organic carbon (OC) and with BC collected from the Yangtze River (BC-YR), (ii) a sediment without OC and with multi-walled carbon nanotubes (MWCNTs), and (iii) a sediment without OC and with fresh wood char. Biodegradation and mineralization of adsorbed phenanthrene by Agrobacterium and XAD-2 assisted abiotic desorption of adsorbed phenanthrene were studied. The results showed that microbes could utilize a fraction of adsorbed phenanthrene by BC and MWCNTs after aging for 21-40d. With aging for 28d, the biodegradation efficiencies of phenanthrene after incubation for 21d were 83.8%, 73.5% and 54.2% for BC-YR, char and MWCNTs, respectively; with aging for 40d, the mineralization rates of (14)C-labeled phenanthrene after incubation for 25d were 38.3%, 25.1% and 24.6%, respectively. The desorption and biodegradation processes showed similar residual concentration of phenanthrene. However, the biodegradation rates were higher than the desorption rates during the fast biodegradation stage, suggesting that bacteria could promote desorption or access and utilize the sorbed phenanthrene. The biodegradation and mineralization efficiencies of phenanthrene associated with MWCNTs were significantly lower than with BC (p<0.01), implying adsorption by MWCNTs may lead to a greater decrease of HOCs bioavailability in the environment.
含碳吸附剂包括黑碳（BC）和碳纳米管，由于它们对沉积物和土壤中疏水性有机化合物（HOCs）的生物有效性的影响，引起了全世界的研究关注。在这项研究中，将（14）C 标记和未标记的菲掺入到三种人工沉积物中：（i）一种来自长江的无无定形有机碳（OC）和 BC 的沉积物（BC-YR），（ii）一种无 OC 和多壁碳纳米管（MWCNTs）的沉积物，和（iii）一种无 OC 和新鲜木炭的沉积物。研究了吸附菲的生物降解和矿化以及 XAD-2 辅助吸附菲的非生物解吸。结果表明，经过 21-40d 的老化后，微生物可以利用 BC 和 MWCNTs 吸附的一部分菲。在 28d 的老化后，经过 21d 孵育后，BC-YR、木炭和 MWCNTs 中菲的生物降解效率分别为 83.8％、73.5％和 54.2％；在 40d 的老化后，经过 25d 孵育后，（14）C 标记的菲的矿化率分别为 38.3％、25.1％和 24.6％。解吸和生物降解过程表现出相似的残留菲浓度。然而，在快速生物降解阶段，生物降解率高于解吸率，这表明细菌可以促进吸附的菲的解吸或生物利用。与 BC 相比，MWCNTs 结合的菲的生物降解和矿化效率明显较低（p<0.01），这意味着 MWCNTs 的吸附可能导致环境中 HOCs 的生物有效性更大程度降低。
