Fragmented micro- and nanoplastics are widespread pollutants with adverse effects on the environment. However, the breakdown process does not end with micro- and nanoplastics but is expected to continue until carbon dioxide has been formed. During this process the plastics will undergo chemical changes and small molecules may be released. We have broken down small amine-modified (∅53 nm) and carboxyl-modified (∅62 nm) polystyrene nanoparticles by UV-B irradiation during 100 days. We see a decreasing size and an oxidation of the nanoparticles over time. Simultaneously, the acute toxicity to zooplankton Daphnia magna decreases. UV-B irradiation releases small, dissolved molecules that are toxic to Daphnia magna. The dissolved molecules include aminated alkyls, styrene remnants and secondary circularization products. The study shows that UV-B radiation can change the original toxicity of nanoplastics and release new toxic substances.

中文翻译：

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UV-B 降解会影响纳米塑料的毒性并导致小的有毒物质的释放


碎片化的微塑料和纳米塑料是广泛存在的污染物，对环境有不利影响。然而，分解过程不会以微塑料和纳米塑料结束，而是会一直持续到形成二氧化碳为止。在此过程中，塑料会发生化学变化，并可能释放出小分子。我们在 100 天内通过 UV-B 照射分解了胺改性 （∅53 nm） 和羧基改性 （∅62 nm） 聚苯乙烯纳米颗粒。随着时间的推移，我们看到纳米颗粒的尺寸减小和氧化。同时，对浮游动物 Daphnia magna 的急性毒性降低。UV-B 照射会释放出对大型溞有毒的溶解小分子。溶解的分子包括胺化烷基、苯乙烯残余物和二次循环产物。研究表明，UV-B 辐射可以改变纳米塑料的原始毒性并释放新的有毒物质。