The algal toxicity of silver engineered nanoparticles and detoxification by exopolymeric substances

详细信息    查看全文

• 作者：Ai-Jun Miao ; Kathy A. Schwehr ; Chen Xu ; Sai-Jin Zhang ; Zhiping Luo ; Antonietta Quigg ; Peter H. Santschi
• 关键词：Ag-ENs ; EPS ; Nanoparticle ; Phytoplankton ; Toxicity
• 刊名：Environmental Pollution
• 出版年：2009
• 出版时间：November 2009
• 年：2009
• 卷：157
• 期：11
• 页码：3034-3041
• 全文大小：400 K

文摘

In this study, we report that silver ions (Ag⁺) from the oxidative dissolution of silver engineered nanoparticles (Ag-ENs) determined the EN toxicity to the marine diatom Thalassiosira weissflogii. Most of the Ag-ENs formed non-toxic aggregates (>0.22 μm) in seawater. When the free Ag⁺ concentration ([Ag⁺]_F) was greatly reduced by diafiltration or thiol complexation, no toxicity was observed, even though the Ag-ENs were better dispersed in the presence of thiols with up to 1.08 × 10⁻⁵ M Ag-ENs found in the <0.22 μm fraction, which are orders of magnitude higher than predicted for the natural aquatic environment. The secretion of polysaccharide-rich algal exopolymeric substances (EPS) significantly increased at increasing [Ag⁺]_F. Both dissolved and particulate polysaccharide concentrations were higher for nutrient-limited cells, coinciding with their higher Ag⁺ tolerance, suggesting that EPS may be involved in Ag⁺ detoxification.