State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing 210046, China.
Chemosphere. 2013 Jan;90(2):527-34. doi: 10.1016/j.chemosphere.2012.08.022. Epub 2012 Sep 7.
Concerns on the potential risks of engineered nanoparticles to the environment are increasing; however, little is known about the effects of carbon nanotubes (CNTs) on the environmental fate of hydrophobic organic pollutants in soil. We incubated radioactive labeled 2,4-dichlorophenol ((14)C-2,4-DCP) in a soil in the presence of various concentrations (0, 2, 20, and 2000 mg kg(-1) dry soil) of single-walled (SWCNTs) and multi-walled (MWCNTs) carbon nanotubes, and determined the mineralization, degradation, and residue distribution of 2,4-DCP in the soil. CNTs were added to the soil either after the spiking of (14)C-2,4-DCP or together with (14)C-2,4-DCP as a mixture. CNTs at the concentration of 2000 mg kg(-1) significantly (P<0.05) inhibited the mineralization of (14)C-2,4-DCP and induced a 2.3- to 3.9-fold increase in the amounts of the non-degraded (14)C-2,4-DCP in the soil after 90 d of incubation. Pre-adsorption of (14)C-2,4-DCP on CNTs showed stronger inhibitory effects on the degradation of (14)C-2,4-DCP, already significant with CNTs at 20 mg kg(-1). In general, SWCNTs had a higher effect on the degradation and residue distribution of 2,4-DCP in the soil than MWCNTs. The inhibitory effects are supposed to be owing to limited activities of soil endogenous microorganisms, potential toxicities of CNTs to the microorganisms, and reduced bioavailability of 2,4-DCP in the presence of CNTs, even though a desorption hysteresis of 2,4-DCP on CNTs was not observed. Our results indicate that CNTs have more significant impacts on the environmental fate of the hydrophobic pollutants entering soil together with CNTs via strong sorption than the pollutants already present in soil.
人们对工程纳米粒子给环境带来的潜在风险的担忧日益增加，然而，对于碳纳米管 (CNTs) 对土壤中疏水性有机污染物环境归宿的影响却知之甚少。我们在含有不同浓度（0、2、20 和 2000 mg kg(-1) 干土）单壁 (SWCNTs) 和多壁 (MWCNTs) CNT 的土壤中孵育放射性标记的 2,4-二氯苯酚 ((14)C-2,4-DCP)，并测定了 2,4-DCP 在土壤中的矿化、降解和残留分布。CNTs 要么在加入 ((14)C-2,4-DCP) 后加入土壤，要么与 ((14)C-2,4-DCP) 一起作为混合物加入土壤。在 2000 mg kg(-1) 的浓度下，CNTs 显著（P<0.05）抑制了 ((14)C-2,4-DCP 的矿化，并在孵育 90 天后导致土壤中非降解 ((14)C-2,4-DCP 的量增加了 2.3-3.9 倍。(14)C-2,4-DCP 预先吸附在 CNTs 上对 (14)C-2,4-DCP 的降解表现出更强的抑制作用，即使在 20 mg kg(-1) 的 CNTs 下也已显著。一般来说，SWCNTs 对 2,4-DCP 在土壤中的降解和残留分布的影响高于 MWCNTs。这种抑制作用可能归因于土壤内源性微生物活性有限、CNTs 对微生物的潜在毒性以及 CNTs 存在时 2,4-DCP 的生物利用度降低，尽管没有观察到 2,4-DCP 在 CNTs 上的解吸滞后。我们的结果表明，与已经存在于土壤中的污染物相比，CNTs 通过强吸附对与 CNTs 一起进入土壤的疏水性污染物的环境归宿有更显著的影响。
