Leiden University College, Leiden University, P.O. Box 13228, 2501, EE, The Hague, the Netherlands; Institute of Environmental Sciences, Leiden University, P.O. Box 9518, 2300, RA Leiden, the Netherlands.
Institute of Environmental Sciences, Leiden University, P.O. Box 9518, 2300, RA Leiden, the Netherlands.
Environ Pollut. 2019 Jul;250:669-675. doi: 10.1016/j.envpol.2019.04.067. Epub 2019 Apr 19.
Even though microplastics are intensively studied, the focus of the research is mainly on relatively short term effects at high doses. Therefore there is a need to shift the focus toward more realistic, longer-term endpoints. Studies with a range of chemicals have shown that the response of populations often differs from studies in which a single organism is exposed in an individual container (as often described within standard ecotox screening assays). Here we investigate the impact of primary microplastics (1-5 μm in size) on a population of Daphnia magna. We first allowed a stable population of D. magna to develop over 29 d, after which the populations were exposed to microplastics for three weeks (concentrations ranging from 10 to 10 particles mL and a control). We found a significant impact of microplastics on the total population of D. magna, with a reduction in the amount of adult daphnids. Importantly, when expressed as total biomass, exposure to 10 microplastics mL resulted in a 21% reduction in total biomass compared to control. These results indicate that exposure to microplastics can result in significant adverse effects on the population of D. magna, including a reduction in the number of individuals as well as total biomass. Given the importance of D. magna in freshwater food webs, both as a grazer as well as a food source, this can potentially impact the functioning of the ecosystem.
尽管微塑料受到了广泛的研究，但研究的重点主要集中在高剂量下的短期影响。因此，有必要将研究重点转向更现实、更长期的终点。一系列化学物质的研究表明，种群的反应通常与在单个容器中暴露单个生物体的研究不同（如标准生态毒性筛选测定中经常描述的那样）。在这里，我们研究了原生微塑料（大小为 1-5μm）对大型溞种群的影响。我们首先让大型溞的稳定种群在 29 天内发育，然后让种群暴露在微塑料中三周（浓度范围从 10 到 10 个颗粒 mL 和一个对照）。我们发现微塑料对大型溞的总种群有显著影响，成体溞的数量减少。重要的是，当以总生物量表示时，与对照相比，暴露于 10 个微塑料 mL 会导致总生物量减少 21%。这些结果表明，暴露于微塑料会对大型溞种群产生重大的不利影响，包括个体数量和总生物量的减少。鉴于大型溞在淡水食物网中的重要性，既是食草动物，也是食物来源，这可能会对生态系统的功能产生影响。
