ECOSPHERE, Department of Biology, Universiteit Antwerpen, Groenenborgerlaan 171, 2020 Antwerpen, Belgium.
Physical Chemistry and Soft Matter, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
Environ Sci Technol. 2023 Oct 31;57(43):16552-16563. doi: 10.1021/acs.est.3c05148. Epub 2023 Oct 19.
The main driver of the potential toxicity of micro- and nanoplastics toward biota is often the release of compounds initially present in the plastic, i.e., polymer additives, as well as environmentally acquired metals and/or organic contaminants. Plastic particles degrade in the environment via various mechanisms and at different rates depending on the particle size/geometry, polymer type, and the prevailing physical and chemical conditions. The rate and extent of polymer degradation have obvious consequences for the uptake/release kinetics and, thus, the bioavailability of compounds associated with plastic particles. Herein, we develop a theoretical framework to describe the uptake and release kinetics of metal ions and organic compounds by plastic particles and apply it to the analysis of experimental data for pristine and aged micro- and nanoplastics. In particular, we elucidate the contribution of transient processes to the overall kinetics of plastic reactivity toward aquatic contaminants and demonstrate the paramount importance of intraparticulate contaminant diffusion.
微塑料和纳米塑料对生物产生潜在毒性的主要驱动因素通常是最初存在于塑料中的化合物的释放，即聚合物添加剂，以及环境中获得的金属和/或有机污染物。塑料颗粒通过各种机制在环境中降解，降解速率因颗粒大小/形状、聚合物类型以及环境中物理和化学条件的不同而不同。聚合物降解的速率和程度对与塑料颗粒相关的化合物的吸收/释放动力学有明显的影响，从而影响其生物可利用性。在此，我们开发了一个理论框架来描述金属离子和有机化合物被塑料颗粒吸收和释放的动力学，并将其应用于分析原始和老化的微塑料和纳米塑料的实验数据。特别是，我们阐明了瞬态过程对塑料颗粒对水生污染物反应动力学的整体影响，并证明了颗粒内污染物扩散的至关重要性。
