科研之友
微信
新浪微博
Facebook
分享链接
摘要
Assessing the dissolution of silver nanoparticles (AgNPs) in laboratory test media and in the aquatic environment is critical for determining toxicity. In the present study, the ion-release kinetics for 20-nm, 50-nm, and 80-nm AgNPs in environmentally relevant freshwaters with different electrical conductivity values (30 mu S/cm, 150 mu S/cm) were examined and related to the associated impact on Daphnia magna. The acute toxicity of the AgNP suspensions to D. magna was assessed after 0 d and 7 d of interaction time between the particles and test media. When 48-h lethal median concentrations were expressed as total silver, D. magna was more sensitive to AgNPs suspended in low ionic strength media relative to higher ionic strength media, with the exception of 50-nm AgNPs suspended in the 150-mu S/cm medium. A 3.3-fold increase in hydrodynamic diameter measured by dynamic light scattering and field flow fractionation was observed over time for 20-nm particles in the 150-mS/cm medium, but only a small increase in aggregation size for 50-nm and 80-nm particles (1.4-fold and 1.2-fold increase, respectively) was observed. At a lower conductivity of 30 mu S/cm, a 1.7-fold, 1.0-fold, and 1.2-fold increase in aggregation size was observed in the 20-nm, 50-nm, and 80-nm particles, respectively. Thus, the impact of higher conductivity test media on increased aggregation and decreased toxicity (after 7 d) was relatively greater for the smaller (20-nm) AgNP higher compared to the 50-80 nm AgNPs. Environ Toxicol Chem 2014; 33: 1783-1791. Published 2014 Wiley Periodicals, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.
- 出版日期2014-8
