Department of Biology, Duke University, Durham, NC, USA.
Ecotoxicology. 2012 Oct;21(7):1867-77. doi: 10.1007/s10646-012-0920-5. Epub 2012 May 9.
Given the demonstrated antimicrobial properties of silver nanoparticles (AgNPs), and the key role that microorganisms play in performing critical ecosystem functions such as decomposition and nutrient cycling, there is growing concern that AgNP pollution may negatively impact ecosystems. We examined the response of streamwater and sediment microorganisms to commercially available 21 ± 17 nm AgNPs, and compared AgNP impacts to those of dissolved-Ag added as AgNO(3). We show that in streamwater, AgNPs and AgNO(3) decreased respiration in proportion to dissolved-Ag concentrations at the end of the incubation (r(2) = 0.78), while in sediment the only measurable effect of AgNPs was a 14 % decrease in sulfate concentration. This contrasts with the stronger effects of dissolved-Ag additions in both streamwater and sediment. In streamwater, addition of dissolved-Ag at a level equivalent to the lowest AgNP dose led to respiration below detection, a 55 % drop in phosphatase enzyme activity, and a 10-fold increase in phosphate concentration. In sediment, AgNO(3) addition at a level equivalent to the highest AgNP addition led to a 34 % decrease in respiration, a 55 % increase in microbial biomass, and a shift in bacterial community composition. The results of this study suggest that, in similar freshwater environments, the short-term biological impacts of AgNPs on microbes are attenuated by the physical and chemical properties of streamwater and sediment.
鉴于银纳米粒子（AgNPs）具有明显的抗菌性能，以及微生物在执行分解和养分循环等关键生态系统功能方面所起的关键作用，人们越来越担心 AgNP 污染可能会对生态系统产生负面影响。我们研究了商业上可用的 21 ± 17nm AgNPs 对溪流水样和沉积物微生物的影响，并将 AgNP 的影响与添加的作为 AgNO3 的溶解态 Ag 进行了比较。我们发现，在溪流水样中，AgNPs 和 AgNO3 的呼吸作用与培养结束时的溶解态 Ag 浓度成比例降低（r2 = 0.78），而在沉积物中，AgNPs 唯一可测量的影响是硫酸盐浓度降低了 14%。这与溶解态 Ag 对溪流水样和沉积物中微生物的更强影响形成了对比。在溪流水样中，添加与最低 AgNP 剂量相当的溶解态 Ag 会导致呼吸作用低于检测水平，磷酸酶活性下降 55%，磷酸盐浓度增加 10 倍。在沉积物中，添加与最高 AgNP 添加量相当的 AgNO3 会导致呼吸作用下降 34%，微生物生物量增加 55%，以及细菌群落组成的变化。本研究的结果表明，在类似的淡水环境中，AgNPs 对微生物的短期生物影响因溪流水样和沉积物的物理和化学性质而减弱。
