Division of Life Science, State Key Laboratory of Marine Pollution, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region, China.
Environ Toxicol Chem. 2014 Mar;33(3):632-40. doi: 10.1002/etc.2471. Epub 2014 Jan 24.
With increasing use of silver nanoparticles (AgNPs), concerns about their potential deleterious effects on aquatic ecosystems have increased. Most previous studies have focused on the toxicity of AgNPs while their bioavailability has been seldom investigated. The present study examined the effects of salinity on the aggregation kinetics as well as the bioavailability of commercial 80-nm citrate-coated AgNPs (c-AgNPs) in the presence or absence of a nonionic surfactant (Tween 20) to marine medaka (Oryzias melastigma). In addition, the uptake of soluble Ag was quantified for comparison and for deducting the uptake of soluble Ag during AgNP exposure by applying a biokinetic model. The authors found that the addition of Tween 20 immediately slowed down the process of aggregation of AgNPs, and an elevated amount of Tween 20 (20 µM) kept AgNPs well dispersed, even in the 30-psu salinity medium. Uptake rate constants (ku ) of AgNPs were less than half the soluble Ag at low salinities (1 psu and 5 psu), while limited bioavailability of c-AgNPs was observed at high salinities (15 psu and 30 psu). However, the Tween 20-stabilized AgNPs (t-AgNPs) were accumulated by medaka at comparable rates as the soluble Ag, indicating the importance of dispersion for bioavailability of AgNPs in a highly ionic environment. The present study provided the first insight of the bioavailability of AgNPs to fish in a high-ionic environment. More studies are needed to gain a full understanding of bioavailability of AgNPs in marine environments.
随着纳米银（AgNPs）使用的增加，人们对其对水生生态系统潜在有害影响的担忧也在增加。大多数先前的研究都集中在 AgNPs 的毒性上，而很少研究其生物利用度。本研究考察了盐度对商业 80nm 柠檬酸包覆的 AgNPs（c-AgNPs）在存在或不存在非离子表面活性剂（吐温 20）时聚集动力学以及生物利用度的影响，以海洋稻蝗（Oryzias melastigma）为模型生物。此外，还定量测定了可溶银的摄取量，以便比较，并通过应用生物动力学模型扣除 AgNP 暴露期间可溶银的摄取量。作者发现，添加吐温 20 会立即减缓 AgNPs 聚集的过程，并且添加高浓度的吐温 20（20µM）可使 AgNPs 保持良好的分散状态，即使在 30-psu 的盐度介质中也是如此。在低盐度（1psu 和 5psu）下，AgNPs 的摄取率常数（ku）不到可溶银的一半，而在高盐度（15psu 和 30psu）下观察到 c-AgNPs 的生物利用度有限。然而，Tween 20 稳定的 AgNPs（t-AgNPs）被稻蝗以与可溶银相当的速率积累，这表明在高离子环境中分散对于 AgNPs 的生物利用度很重要。本研究首次提供了鱼类在高离子环境中对 AgNPs 生物利用度的见解。需要进一步研究以充分了解海洋环境中 AgNPs 的生物利用度。
