US Environmental Protection Agency, Office of Research and Development, Cincinnati, Ohio, USA.
Environ Toxicol Chem. 2010 Dec;29(12):2742-50. doi: 10.1002/etc.329. Epub 2010 Oct 1.
Relatively little is known about the behavior and toxicity of nanoparticles in the environment. Objectives of work presented here include establishing the toxicity of a variety of silver nanoparticles (AgNPs) to Daphnia magna neonates, assessing the applicability of a commonly used bioassay for testing AgNPs, and determining the advantages and disadvantages of multiple characterization techniques for AgNPs in simple aquatic systems. Daphnia magna were exposed to a silver nitrate solution and AgNPs suspensions including commercially available AgNPs (uncoated and coated), and laboratory-synthesized AgNPs (coated with coffee or citrate). The nanoparticle suspensions were analyzed for silver concentration (microwave acid digestions), size (dynamic light scattering and electron microscopy), shape (electron microscopy), surface charge (zeta potentiometer), and chemical speciation (X-ray absorption spectroscopy, X-ray diffraction). Toxicities of filtered (100 nm) versus unfiltered suspensions were compared. Additionally, effects from addition of food were examined. Stock suspensions were prepared by adding AgNPs to moderately hard reconstituted water, which were then diluted and used straight or after filtration with 100-nm filters. All nanoparticle exposure suspensions, at every time interval, were digested via microwave digester and analyzed by inductively coupled argon plasma-optical emission spectroscopy or graphite furnace-atomic absorption spectroscopy. Dose-response curves were generated and median lethal concentration (LC50) values calculated. The LC50 values for the unfiltered particles were (in µg/L): 1.1 ± 0.1-AgNO(3) ; 1.0 ± 0.1-coffee coated; 1.1 ± 0.2-citrate coated; 16.7 ± 2.4 Sigma Aldrich Ag-nanoparticles (SA) uncoated; 31.5 ± 8.1 SA coated. LC50 values for the filtered particles were (in µg/L): 0.7 ± 0.1-AgNO(3) ; 1.4 ± 0.1-SA uncoated; 4.4 ± 1.4-SA coated. The LC50 resulting from the addition of food was 176.4 ± 25.5-SA coated. Recommendations presented in this study include AgNP handling methods, effects from sample preparation, and advantages/disadvantages of different nanoparticle characterization techniques.
关于纳米颗粒在环境中的行为和毒性，人们知之甚少。本研究工作的目的包括确定各种银纳米颗粒（AgNPs）对大型溞幼体的毒性，评估一种常用的测试 AgNPs 的生物测定法的适用性，并确定多种简单水生系统中 AgNPs 特性描述技术的优缺点。大型溞幼体暴露于硝酸银溶液和 AgNPs 悬浮液中，包括市售的 AgNPs（未涂层和涂层）和实验室合成的 AgNPs（用咖啡或柠檬酸盐涂层）。通过微波酸消解对纳米颗粒悬浮液进行银浓度分析，通过动态光散射和电子显微镜分析粒径，通过电子显微镜分析形状，通过zeta 电位计分析表面电荷，通过 X 射线吸收光谱和 X 射线衍射分析化学形态。比较了过滤（100nm）与未过滤悬浮液的毒性。此外，还研究了添加食物的影响。通过将 AgNPs 添加到中等硬度的重组水中来制备储备悬浮液，然后将其稀释并直接使用或在 100nm 过滤器过滤后使用。所有纳米颗粒暴露悬浮液在每个时间间隔都通过微波消解器进行消解，并通过电感耦合氩等离子体-光学发射光谱或石墨炉-原子吸收光谱进行分析。生成剂量反应曲线并计算半数致死浓度（LC50）值。未过滤颗粒的 LC50 值为（µg/L）：1.1 ± 0.1-AgNO3；1.0 ± 0.1-咖啡涂层；1.1 ± 0.2-柠檬酸盐涂层；16.7 ± 2.4 Sigma Aldrich Ag-纳米颗粒（SA）未涂层；31.5 ± 8.1 SA 涂层。过滤颗粒的 LC50 值为（µg/L）：0.7 ± 0.1-AgNO3；1.4 ± 0.1-SA 未涂层；4.4 ± 1.4-SA 涂层。添加食物后的 LC50 值为 176.4 ± 25.5-SA 涂层。本研究提出的建议包括 AgNP 处理方法、样品制备的影响以及不同纳米颗粒特性描述技术的优缺点。
