Sakka Yvonne, Skjolding Lars Michael, Mackevica Aiga, Filser Juliane, Baun Anders
University of Bremen, Center for Environmental Research and Technology, General and Theoretical Ecology, Leobener Str., 28359 Bremen, Germany.
Technical University of Denmark (DTU), Department of Environmental Engineering, Miljoevej 113, 2800 Kgs., Lyngby, Denmark.
Aquat Toxicol. 2016 Aug;177:526-35. doi: 10.1016/j.aquatox.2016.06.025. Epub 2016 Jul 1.
While differences in silver nanoparticle (AgNP) colloidal stability, surface potential, or acute aquatic toxicity for differently stabilized AgNP have often been reported, these have rarely been studied in long-term ecotoxicity tests. In the current study, we investigated the chronic toxicity of AgNP to Daphnia magna over a 21-day period with two different stabilizers (citrate and detergent), representative for charge and sterical stabilizers, respectively. This was coupled with a series of short-term experiments, such as mass balance and uptake/depuration testing, to investigate the behavior of both types of AgNP during a typical media exchange period in the D. magna test for chronic toxicity. As expected, the sterically stabilized AgNP was more stable in the test medium, also in the presence of food; however, a higher uptake of silver after 24h exposure of the charge stabilized AgNP was found compared to the detergent-stabilized AgNP (0.046±0.006μgAgμgDW(-1) and 0.023±0.005μgAgμgDW(-1), respectively). In accordance with this, the higher reproductive effects and mortality were found for the charge-stabilized than for the sterically-stabilized silver nanoparticles in 21-d tests for chronic toxicity. LOEC was 19.2μgAgL(-1) for both endpoints for citrate-coated AgNP and >27.5μgAgL(-1) (highest tested concentration for detergent-stabilized AgNP). This indicates a link between uptake and toxicity. The inclusion of additional short-term experiments on uptake and depuration is recommended when longer-term chronic experiments with nanoparticles are conducted.
虽然经常有报道称不同稳定化的银纳米颗粒（AgNP）在胶体稳定性、表面电位或急性水生毒性方面存在差异，但这些差异在长期生态毒性试验中很少被研究。在本研究中，我们用两种不同的稳定剂（柠檬酸盐和去污剂）分别代表电荷稳定剂和空间稳定剂，研究了AgNP在21天内对大型溞的慢性毒性。这与一系列短期实验相结合，如质量平衡和摄取/净化测试，以研究在大型溞慢性毒性测试的典型培养基交换期间这两种类型的AgNP的行为。正如预期的那样，空间稳定化的AgNP在测试介质中更稳定，即使在有食物的情况下也是如此；然而，与去污剂稳定化的AgNP相比，电荷稳定化的AgNP在暴露24小时后银的摄取量更高（分别为0.046±0.006μgAgμgDW(-1)和0.023±0.005μgAgμgDW(-1)）。据此，在21天的慢性毒性测试中，电荷稳定化的银纳米颗粒比空间稳定化的银纳米颗粒具有更高的生殖效应和死亡率。柠檬酸盐包被的AgNP两个终点的最低观察效应浓度（LOEC）均为19.2μgAgL(-1)，而去污剂稳定化的AgNP的最高测试浓度>27.5μgAgL(-1)。这表明摄取与毒性之间存在联系。当进行纳米颗粒的长期慢性实验时，建议加入关于摄取和净化的额外短期实验。
