Institute of Hydraulic Engineering and Water Resources Management, RWTH-Aachen University, Mies-van-der-Rohe-Straße 17, 52074 Aachen, Germany.
Environ Sci Technol. 2023 Jul 18;57(28):10393-10403. doi: 10.1021/acs.est.3c02189. Epub 2023 Jul 6.
Littered plastics are partly introduced into water bodies, ultimately transporting this waste to the shores and oceans. At the shore, ultraviolet (UV) radiation (also present in other environmental compartments) and wave breaking cause plastics to degrade and fragment into smaller particles, called microplastics, if below 5 mm. Since these plastics' surfaces can act as vectors for hydrophobic (toxic) chemical substances (e.g., per- and polyfluoroalkyl substances (PFAS)) and leach (toxic) chemicals into the water, the increase in the surface area through the fragmentation of plastics becomes relevant. Studies investigating different effects on the fragmentation of plastics have mostly disregarded a sufficient mechanical component for fragmentation, focusing on degradation by UV radiation. Therefore, this study investigated the impact of the mechanical fragmentation drivers, wave impact, and sediment abrasion on the fragmentation of expanded polystyrene (EPS), high-density polyethylene (PE-HD), and polyethylene terephthalate (PET) particles. In a newly designed test facility called Slosh-Box, the mentioned impacts were investigated concurrently. The results reveal that the mechanical impacts alone are sufficient for plastic fragmentation, and the test facility is suitable for fragmentation investigations. Furthermore, the increase in surface area was determined via scanning electron microscopy. For EPS, the surface area increased more than 2370-fold, while for PE-HD and PET, surface areas increased between 1 and 8.6 times. Concluding from the results, the new test facility is suitable for plastic fragmentation studies. In addition, sediment was revealed to be a relevant fragmentation driver, which should be included in every experiment investigating the fragmentation of plastic in a nearshore environment independent of other drivers like UV radiation.
散落的塑料部分被引入水体，最终将这些废物输送到海岸和海洋。在海岸边，紫外线（UV）辐射（也存在于其他环境隔室中）和波浪破碎导致塑料降解并碎裂成较小的颗粒，称为微塑料，如果小于 5 毫米。由于这些塑料表面可以作为疏水性（有毒）化学物质（例如，全氟和多氟烷基物质（PFAS））的载体，并将（有毒）化学物质浸出到水中，因此通过塑料碎片的表面积增加变得相关。研究不同塑料碎片影响的研究大多忽略了足够的机械碎片组件，而是侧重于 UV 辐射的降解。因此，本研究调查了机械碎片驱动因素、波浪冲击和泥沙磨损对膨胀聚苯乙烯（EPS）、高密度聚乙烯（PE-HD）和聚对苯二甲酸乙二醇酯（PET）颗粒碎片的影响。在一个名为 Slosh-Box 的新设计测试设施中，同时研究了上述影响。结果表明，仅机械冲击就足以进行塑料碎片，并且该测试设施适合碎片研究。此外，还通过扫描电子显微镜确定了表面积的增加。对于 EPS，表面积增加了 2370 多倍，而对于 PE-HD 和 PET，表面积增加了 1 到 8.6 倍。从结果中得出结论，新的测试设施适合塑料碎片研究。此外，泥沙被证明是一个相关的碎片驱动因素，在研究近岸环境中塑料碎片时，无论其他驱动因素（如 UV 辐射）如何，都应将泥沙纳入每个实验中。
