Environ Sci Technol. 2015 Jan 20;49(2):1165-72. doi: 10.1021/es5050166.
Silver nanoparticles (AgNP) are increasingly used as antimicrobials in consumer products. Subsequently released into aquatic environments, they are likely to come in contact with microbial communities like periphyton, which plays a key role as a primary producer in stream ecosystems. At present, however, very little is known about the effects of nanoparticles on processes mediated by periphyton communities. We assessed the effects of citrate-coated silver nanoparticles and silver ions (dosed as AgNO3) on five functional end points reflecting community and ecosystem-level processes in periphyton: photosynthetic yield, respiration potential, and the activity of three extracellular enzymes. After 2 h of exposure in experimental microcosms, AgNP and AgNO3 inhibited respiration and photosynthesis of periphyton and the activities of two of the three extracellular enzymes. Addition of a chelating ligand that complexes free silver ions indicated that, in most cases, toxicity of AgNP suspensions was caused by Ag(I) dissolved from the particles. However, these suspensions inhibited one of the extracellular enzymes (leucine aminopeptidase), pointing to a specific nanoparticle effect independent of the dissolved Ag(I). Thus, our results show that both silver nanoparticles and silver ions have potential to disrupt basic metabolic functions and enzymatic resource acquisition of stream periphyton.
银纳米粒子（AgNP）作为抗菌剂越来越多地应用于消费产品。随后释放到水生环境中，它们很可能与微生物群落（如周丛生物）接触，后者在溪流生态系统中作为初级生产者起着关键作用。然而，目前对于纳米颗粒对周丛生物群落介导的过程的影响知之甚少。我们评估了柠檬酸银纳米粒子和银离子（以 AgNO3 的形式投加）对反映周丛生物群落和生态系统水平过程的五个功能终点的影响：光合产量、呼吸潜能和三种胞外酶的活性。在实验微宇宙中暴露 2 小时后，AgNP 和 AgNO3 抑制了周丛生物的呼吸和光合作用以及三种胞外酶中的两种的活性。添加一种螯合剂以络合游离银离子表明，在大多数情况下，AgNP 悬浮液的毒性是由从颗粒中溶解的 Ag（I）引起的。然而，这些悬浮液抑制了一种胞外酶（亮氨酸氨肽酶），这表明存在一种独立于溶解的 Ag（I）的特定纳米颗粒效应。因此，我们的结果表明，银纳米粒子和银离子都有可能破坏溪流周丛生物的基本代谢功能和酶资源获取。
