In this study, the effect of ZnO nanoparticles and ZnCl2 on growth, reproduction and accumulation of zinc in Daphnia magna was determined in a 21-day chronic toxicity test. A variety of techniques were used to distinguish the free zinc ion, dissolved, nanoparticle and aggregated zinc fraction in the Daphnia test medium. The results showed similar chronic effects on growth, reproduction and accumulation for the ZnO nanoparticles (EC10, 20, 50 reproduction: 0.030, 0.049, 0.112 mg Zn/l) and the ZnCl2 (EC10, 20, 50 reproduction: 0.014, 0.027, 0.082 mg Zn/l). A large fraction of the nanoparticles rapidly dissolved after introduction in the exposure medium. Aggregation of nanoparticles was also observed but within 48 h of exposure most of these ZnO aggregates were dissolved. Based on the combined dissolution kinetics and toxicity results, it can be concluded that the toxicological effects of ZnO nanoparticles at the chronic level can be largely attributed to the dissolved fraction rather than the nanoparticles or initially formed aggregates.

中文翻译：

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ZnO纳米颗粒和ZnCl2对水蚤的慢性毒性，以及使用不同的方法评估纳米颗粒的聚集和溶解。

在这项研究中，通过21天的慢性毒性试验确定了ZnO纳米颗粒和ZnCl2对大型蚤中锌的生长，繁殖和积累的影响。使用多种技术来区分水蚤测试介质中的游离锌离子，溶解的纳米颗粒和聚集的锌部分。结果表明，对于ZnO纳米颗粒（EC10，20，50的再生：0.030，0.049，0.112 mg Zn / l）和ZnCl2（EC10，20，50的再生：0.014，0.027，0.082）的生长，繁殖和积累具有类似的慢性影响。毫克锌/升）。大部分纳米颗粒在引入曝光介质后迅速溶解。还观察到纳米粒子的聚集，但是在暴露的48小时内，大多数这些ZnO聚集体被溶解了。综合溶出动力学和毒性结果，