Institut de Physique du Globe de Paris, UMR 7154, Paris Diderot University, Sorbonne Paris Cité, Paris, France.
Environ Toxicol Chem. 2014 Feb;33(2):341-9. doi: 10.1002/etc.2447. Epub 2014 Jan 7.
The increasing production of nanoparticles has raised strong concerns regarding their environmental release. In life cycle scenarios of nanoparticles, marine systems constitute one of the main final compartments, and the fate of nanoparticles in marine environments needs to be assessed. The dissolution kinetics of commercial uncoated and organic-coated ZnO nanoparticles in synthetic seawater were investigated using the Donnan membrane technique and 1000-Da pore size ultrafiltration. Uncoated nanoparticles reach a maximum dissolution within the first hour, approximately 24% of total ZnO at pH 8.2, and 4% at pH 7.7, followed by secondary carbonated phase precipitation (hydrozincite) until the system reaches a steady state after 30 d of interaction. Assuming a pseudo first-order kinetics for hydrozincite precipitation allowed calculation of kinetics constant values k'(p) of -208 × 10(-4 ) mol L(-1) h(-1 ) ± 15 × 10(-4) mol L(-1) h(-1) (standard deviation) at pH 7.7, and -57 × 10(-4 ) mol L(-1) h(-1 ) ± 11 × 10(-4) mol L(-1) h(-1) at pH 8.2. The presence of an organic coating drastically modifies the life cycle of nanoparticles, with a maximum dissolution reached after 7 d of interaction, followed by a stationary phase lasting from 1 wk to 3 wk, and a subsequent Zn carbonate precipitation until a steady state is reached after 1.5 mo. Monitoring changes in the physicochemical parameters of nanoparticles after exposure to synthetic seawater constitutes an important step in predicting their fate in environmental systems, with major implications for ecotoxicological studies in which metallic speciation is required for toxicity evaluation.
纳米颗粒产量的增加引起了人们对其环境释放的强烈关注。在纳米颗粒的生命周期情景中，海洋系统是主要的最终隔室之一，因此需要评估纳米颗粒在海洋环境中的命运。本研究采用唐南膜技术和 1000-Da 孔径超滤，研究了商业未涂层和有机涂层 ZnO 纳米颗粒在合成海水中的溶解动力学。在 pH 值为 8.2 时，未涂层纳米颗粒在最初的 1 小时内达到最大溶解量，约为总 ZnO 的 24%，在 pH 值为 7.7 时为 4%，随后发生二次碳酸相沉淀（水锌矿），直到 30 天的相互作用后达到稳定状态。假设水锌矿沉淀的假一级动力学允许计算动力学常数 k'(p)的值为 -208 × 10(-4) mol L(-1) h(-1) ± 15 × 10(-4) mol L(-1) h(-1)（标准偏差）在 pH 值为 7.7 时，-57 × 10(-4) mol L(-1) h(-1) ± 11 × 10(-4) mol L(-1) h(-1) 在 pH 值为 8.2 时。有机涂层的存在极大地改变了纳米颗粒的生命周期，在 7 天的相互作用后达到最大溶解，随后是持续 1 周到 3 周的稳定期，随后是 Zn 碳酸盐沉淀，直到 1.5 个月后达到稳定状态。监测纳米颗粒在暴露于合成海水后的物理化学参数变化是预测其在环境系统中命运的重要步骤，这对需要进行毒性评估的金属形态学的生态毒理学研究具有重要意义。
