Wilke Carolyn M, Tong Tiezheng, Gaillard Jean-François, Gray Kimberly A
Department of Civil and Environmental Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Environ Sci Technol. 2016 Oct 18;50(20):11302-11310. doi: 10.1021/acs.est.6b02271. Epub 2016 Oct 4.
Engineered nanomaterials (ENMs) are incorporated into thousands of commercial products, and their release into environmental systems creates complex mixtures with unknown toxicological outcomes. To explore this scenario, we probe the chemical and toxicological interactions of nanosilver (n-Ag) and nanotitania (n-TiO) in Lake Michigan water, a natural aqueous medium, under dark conditions. We find that the presence of n-Ag induces a stress response in Escherichia coli, as indicated by a decrease in ATP production observed at low concentrations (in the μg L range), with levels that are environmentally relevant. However, when n-Ag and n-TiO are present together in a mixture, n-TiO attenuates the toxicity of n-Ag at and below 20 μg L by adsorbing Ag. We observe, however, that toxic stress cannot be explained by dissolved silver concentrations alone and, therefore, must also depend on silver associated with the nanoscale fraction. Although the attenuating effect of n-TiO on n-Ag's toxicity is limited, this study emphasizes the importance of probing the toxicity of ENM mixtures under environmental conditions to assess how chemical interactions between nanoparticles change the toxicological effects of single ENMs in unexpected ways.
工程纳米材料（ENMs）被纳入数千种商业产品中，它们释放到环境系统中会形成具有未知毒理学结果的复杂混合物。为了探究这种情况，我们在黑暗条件下，对密歇根湖水中纳米银（n-Ag）和纳米二氧化钛（n-TiO）在天然水性介质中的化学和毒理学相互作用进行了研究。我们发现，n-Ag的存在会在大肠杆菌中引发应激反应，低浓度（μg/L范围内）时ATP产量下降表明了这一点，其浓度与环境相关。然而，当n-Ag和n-TiO以混合物形式同时存在时，n-TiO通过吸附银在20μg/L及以下浓度时减弱了n-Ag的毒性。然而，我们观察到，毒性应激不能仅用溶解的银浓度来解释，因此，它还必须取决于与纳米级部分相关的银。尽管n-TiO对n-Ag毒性的减弱作用有限，但这项研究强调了在环境条件下探究ENM混合物毒性的重要性，以评估纳米颗粒之间的化学相互作用如何以意想不到的方式改变单一ENM的毒理学效应。
