Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.
Environ Sci Technol. 2012 Aug 7;46(15):8458-66. doi: 10.1021/es301802g. Epub 2012 Jul 13.
Concurrent with the increasing production and application of carbon nanotubes (CNTs) comes an increasing likelihood of CNTs presenting in the aquatic environment, and thereby potentially threatening aquatic organisms via toxic mechanisms that are, at present, poorly understood. This study systematically investigated the toxicity of three multiwalled CNT (MWCNT) samples toward a green alga (Chlorella sp.), focusing on examining and quantifying the contributions of five possible mechanisms to the algal growth inhibition. The results showed that the MWCNTs significantly inhibited the algal growth. The contribution of metal catalyst residues in the MWCNTs to the algal growth inhibition was negligible, as was the contribution from the MWCNTs' adsorption of nutrient elements. The algal toxicity of MWCNTs could mainly be explained by the combined effects of oxidative stress, agglomeration and physical interactions, and shading effects, with the quantitative contributions from these mechanisms depending on the MWCNT size and concentration. At MWCNT concentrations around 96 h IC(50), the oxidative stress accounted for approximately 50% of the algal growth inhibition, whereas the agglomeration and physical interactions, and the shading effects each took approximately 25% of the responsibility.
随着碳纳米管（CNTs）的产量和应用的增加，CNTs 有可能出现在水生环境中，并通过目前了解甚少的毒性机制对水生生物构成潜在威胁。本研究系统地研究了三种多壁碳纳米管（MWCNT）样品对绿藻（Chlorella sp.）的毒性，重点考察和量化了五种可能的机制对藻类生长抑制的贡献。结果表明，MWCNTs 显著抑制了藻类的生长。MWCNTs 中的金属催化剂残留物对藻类生长抑制的贡献可以忽略不计，MWCNTs 对营养元素的吸附也没有贡献。MWCNTs 对藻类的毒性主要可以用氧化应激、团聚和物理相互作用以及遮光效应的综合作用来解释，这些机制的定量贡献取决于 MWCNT 的尺寸和浓度。在 MWCNT 浓度接近 96 h IC（50）时，氧化应激约占藻类生长抑制的 50%，而团聚和物理相互作用以及遮光效应各占约 25%。
