Centre for Environmental Contaminants Research, CSIRO Land and Water, Locked Bag 2007, Kirrawee, NSW 2232, Australia.
Chemosphere. 2013 Sep;93(2):359-65. doi: 10.1016/j.chemosphere.2013.04.096. Epub 2013 May 31.
The increased use of silver nanomaterials presents a risk to aquatic systems due to the high toxicity of silver. The stability, dissolution rates and toxicity of citrate- and polyvinylpyrrolidone-coated silver nanoparticles (AgNPs) were investigated in synthetic freshwater and natural seawater media, with the effects of natural organic matter investigated in freshwater. When sterically stabilised by the large PVP molecules, AgNPs were more stable than when charge-stabilised using citrate, and were even relatively stable in seawater. In freshwater and seawater, citrate-coated AgNPs (Ag-Cit) had a faster rate of dissolution than PVP-coated AgNPs (Ag-PVP), while micron-sized silver exhibited the slowest dissolution rate. However, similar dissolved silver was measured for both AgNPs after 72h in freshwater (500-600μgL(-1)) and seawater (1300-1500μgL(-1)), with higher concentrations in seawater attributed to chloride complexation. When determined on a mass basis, the 72-h IC50 (inhibitory concentration giving 50% reduction in algal growth rate) for Pseudokirchneriella subcapitata and Phaeodactylum tricornutum and the 48-h LC50 for Ceriodaphnia dubia exposure to Ag(+) (1.1, 400 and 0.11μgL(-1), respectively), Ag-Cit (3.0, 2380 and 0.15μgL(-1), respectively) and Ag-PVP (19.5, 3690 and 2.0μgL(-1), respectively) varied widely, with toxicity in the order Ag(+)>Ag-Cit>Ag-PVP. Micron-sized silver treatments elicited much lower toxicity than ionic Ag(+) or AgNP to P. subcapitata. However, when related to the dissolved silver released from the nanoparticles the toxicities were similar to ionic silver treatments. The presence of natural organic matter stabilised the particles and reduced toxicity in freshwater. These results indicate that dissolved silver was responsible for the toxicity and highlight the need to account for matrix components such as chloride and organic matter in natural waters that influence AgNP fate and mitigate toxicity.
由于银的高毒性，纳米银材料的大量使用对水生系统构成了风险。在合成淡水和天然海水中研究了柠檬酸和聚乙烯吡咯烷酮包覆的银纳米颗粒（AgNPs）的稳定性、溶解速率和毒性，并在淡水中研究了天然有机物的影响。当被大的 PVP 分子空间稳定时，AgNPs 比使用柠檬酸稳定时更稳定，甚至在海水中也相对稳定。在淡水和海水中，柠檬酸包覆的 AgNPs（Ag-Cit）的溶解速率比聚乙烯吡咯烷酮包覆的 AgNPs（Ag-PVP）快，而微米级的银表现出最慢的溶解速率。然而，在淡水（500-600μg/L）和海水中（1300-1500μg/L），AgNPs 在 72 小时后测量到相似的溶解银浓度，海水中的浓度较高归因于氯化物络合。以质量为基础，斜生栅藻和三角褐指藻的 72 小时 IC50（抑制藻类生长率 50%的抑制浓度）和溞属 48 小时 LC50 暴露于 Ag(+)（分别为 1.1、400 和 0.11μg/L）、Ag-Cit（分别为 3.0、2380 和 0.15μg/L）和 Ag-PVP（分别为 19.5、3690 和 2.0μg/L）差异很大，毒性顺序为 Ag(+)>Ag-Cit>Ag-PVP。微米级的银处理对斜生栅藻的毒性远低于离子 Ag(+)或 AgNP。然而，当与从纳米颗粒中释放的溶解银相关时，毒性与离子银处理相似。天然有机物的存在稳定了颗粒并降低了淡水中的毒性。这些结果表明，溶解的银是毒性的原因，并强调需要考虑到自然水中的氯和有机物等基质成分，这些成分影响 AgNP 的命运并减轻毒性。
