Department of Biochemistry and Structural Biology, Lund University, Lund University, P.O. Box 118, SE-221 00, Lund, Sweden.
NanoLund, Lund University, Box 118, SE-221 00, Lund, Sweden.
Sci Rep. 2020 Apr 6;10(1):5979. doi: 10.1038/s41598-020-63028-1.
Plastics are widely used in todays society leading to an accelerating amount of plastic waste entering natural ecosystems. Over time these waste products degrade to micro- and, eventually, nanoplastic particles. Therefore, the break-down of plastics may become a critical threat to aquatic ecosystems and several short term studies have demonstrated acute toxicity of nanoplastics on aquatic organisms. However, our knowledge about effects of chronic or life-time exposure on freshwater invertebrates remains elusive. Here, we demonstrate results from life-time exposure (103 days) of a common freshwater invertebrate, Daphnia magna, exposed to sub-lethal concentrations of polystyrene nanoparticles. 53 nm positively charged aminated polystyrene particles were lethal at concentration of 0.32 mg/L which is two magnitudes lower than previously used concentrations in short-term (24 h) tests. At this concentration the life-time of individuals was shortened almost three times. Negatively charged carboxylated 26 and 62 nm polystyrene particles, previously demonstrated to be non-toxic at 25 and 50 mg/L concentrations in short-term tests, were toxic to D. magna at all concentrations used in our long-term study. Although total reproductive output was not significantly affected at increasing concentrations of polystyrene nanoparticles, there was a decreasing trend in the number of offspring over their life-time. Hence, in order to understand how the potential future environmental problem of nanoplastic particles may affect biota, long-term or life-time studies resembling environmental concentrations should be performed in order to provide information for predictions of future scenarios in natural aquatic environments.
塑料在当今社会中被广泛应用，导致大量塑料废物加速进入自然生态系统。随着时间的推移，这些废物会降解为微塑料，最终降解为纳米塑料颗粒。因此，塑料的分解可能成为水生生态系统的一个关键威胁，一些短期研究已经证明了纳米塑料对水生生物的急性毒性。然而，我们对慢性或终生暴露对淡水无脊椎动物的影响的了解仍然难以捉摸。在这里，我们展示了一种常见的淡水无脊椎动物——大型溞（Daphnia magna）在亚致死浓度的聚苯乙烯纳米颗粒中进行终生暴露（103 天）的结果。正电荷氨基化的 53nm 聚苯乙烯颗粒在浓度为 0.32mg/L 时是致命的，这比以前在短期（24 小时）试验中使用的浓度低两个数量级。在这个浓度下，个体的寿命缩短了近三倍。以前在短期试验中证明在 25 和 50mg/L 浓度下无毒的负电荷羧化的 26nm 和 62nm 聚苯乙烯颗粒，在我们的长期研究中，所有使用的浓度对大型溞都是有毒的。虽然聚苯乙烯纳米颗粒浓度增加对总繁殖输出没有显著影响，但随着时间的推移，后代数量呈下降趋势。因此，为了了解未来纳米塑料颗粒可能对生物群产生的潜在环境问题，应该进行类似于环境浓度的长期或终生研究，以便为预测自然水生环境中的未来情景提供信息。
