Department of Aquatic Ecotoxicology, Faculty of Biological Sciences, Goethe University Frankfurt am Main, Max-von-Laue-Str. 13, 60438 Frankfurt am Main, Germany.
Department of Biology, Norwegian University of Science and Technology, 5 Høgskoleringen, 7491 Trondheim, Norway.
Environ Pollut. 2020 May;260:113904. doi: 10.1016/j.envpol.2019.113904. Epub 2019 Dec 31.
Several studies have investigated the effects of nano- and microplastics on daphnids as key freshwater species. However, while information is abundant on the acute toxicity of plastic beads, little is known regarding the multigenerational effects of irregular microplastics. In addition, a comparison of microplastics to naturally occurring particles is missing. Therefore, we investigated the effects of irregular, secondary polystyrene microplastics (<63 μm) and kaolin as natural reference particle on the survival, reproduction, and growth of Daphnia magna over four generations under food-limited conditions. Additionally, we tested the sensitivity of the neonates in each generation to a reference compound as a proxy for offspring fitness. Exposure to high concentrations of microplastics (10,000 and 2000 particles mL) reduced daphnid survival, resulting in extinction within one and four generations, respectively. Microplastics also affected reproduction and growth. Importantly, an exposure to kaolin at similar concentrations did not induce negative effects. The sensitivity of neonates to potassium dichromate was not affected by maternal exposure to particles. Taken together, our study demonstrates that irregular PS particles are more toxic than natural kaolin in daphnids exposed over multiple generations under food limitation. Thus, our work builds towards more realistic exposure scenarios needed to better understand the impacts of microplastics on zooplankton.
已有多项研究调查了纳米和微塑料对作为关键淡水物种的水蚤的影响。然而，尽管有关塑料珠急性毒性的信息丰富，但对于不规则微塑料的多代影响却知之甚少。此外，缺少对微塑料与天然存在的颗粒的比较。因此，我们在食物限制条件下，通过 4 个世代的研究，调查了不规则的、次生聚苯乙烯微塑料（<63μm）和高岭土作为天然参考颗粒对大型溞生存、繁殖和生长的影响。此外，我们还测试了每一代的幼体对参考化合物的敏感性，作为后代适应性的替代指标。暴露于高浓度的微塑料（10000 个和 2000 个颗粒/mL）降低了水蚤的存活率，分别导致在一代和四代内灭绝。微塑料还影响了繁殖和生长。重要的是，在相似浓度下暴露于高岭土不会产生负面影响。幼体对重铬酸钾的敏感性不受母体颗粒暴露的影响。总的来说，我们的研究表明，在食物限制条件下，多代暴露于不规则 PS 颗粒比天然高岭土对水蚤更具毒性。因此，我们的工作朝着更现实的暴露情景迈进，以更好地了解微塑料对浮游动物的影响。
