Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China.
J Hazard Mater. 2022 Mar 5;425:127842. doi: 10.1016/j.jhazmat.2021.127842. Epub 2021 Nov 21.
Microplastics (MPs) are ubiquitous in drinking water and pose potential threats to human health. Despite increasingly attentions on the toxicity of MPs, the deleterious effects of MPs after chlorine disinfection, which might be a more accessible form of MPs, has rarely been considered. Here, we first treated pristine polystyrene microplastics (PS-MPs) with chlorine to simulate the reactions that occur during drinking water treatment, and investigated and compared the cytotoxicity of chlorinated PS-MPs to those of pristine PS-MPs. Chlorine disinfection did not change the size of pristine PS-MPs, but increased the surface roughness. In addition, abundant carbon-chlorine bonds and persistent free radicals were generated on the surface of chlorinated PS-MPs. Compared with pristine PS-MPs, chlorinated PS-MPs markedly inhibited the cell proliferation, changed cellular morphology, destroyed cell membrane integrity, induced cell inflammatory response and apoptosis. Proteomics confirmed the difference in interactions with intracellular proteins between these particles. Furthermore, we found that the regulation of PI3K/AKT and Bcl-2/Bax pathways, oxidative stress-triggered mitochondrial depolarization, and the activation of caspase cascade were identified as the underlying mechanisms for the enhanced apoptosis ratio in GES-1 cells when exposed to chlorinated PS-MPs. This exacerbated cytotoxicity could be explained by the enhanced surface roughness and changed surface chemistry of these PS-MPs after chlorine disinfection. This work discloses the impacts of chlorine disinfection on the cytotoxicity of PS-MPs, which provides new insights for a more systematic risk assessment of MPs.
微塑料（MPs）广泛存在于饮用水中，对人类健康构成潜在威胁。尽管越来越多的人关注 MPs 的毒性，但经过氯消毒后的 MPs 的有害影响却很少被考虑，因为这可能是一种更容易获得的 MPs 形式。在这里，我们首先用氯处理原始聚苯乙烯微塑料（PS-MPs），以模拟饮用水处理过程中发生的反应，并研究和比较了氯代 PS-MPs 对原始 PS-MPs 的细胞毒性。氯消毒并没有改变原始 PS-MPs 的大小，但增加了表面粗糙度。此外，在氯代 PS-MPs 的表面生成了丰富的碳-氯键和稳定的自由基。与原始 PS-MPs 相比，氯代 PS-MPs 明显抑制了细胞增殖，改变了细胞形态，破坏了细胞膜完整性，诱导了细胞炎症反应和细胞凋亡。蛋白质组学证实了这些颗粒与细胞内蛋白质相互作用的差异。此外，我们发现，当 GES-1 细胞暴露于氯代 PS-MPs 时，PI3K/AKT 和 Bcl-2/Bax 通路的调节、氧化应激引发的线粒体去极化以及半胱氨酸天冬氨酸蛋白酶级联的激活被确定为细胞凋亡比率增加的潜在机制。这种加剧的细胞毒性可以用这些 PS-MPs 经过氯消毒后表面粗糙度的增加和表面化学性质的改变来解释。这项工作揭示了氯消毒对 PS-MPs 细胞毒性的影响，为 MPs 的更系统风险评估提供了新的见解。
