Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
Key Laboratory of Wetland Ecology and Environment, State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
J Hazard Mater. 2024 Nov 5;479:135651. doi: 10.1016/j.jhazmat.2024.135651. Epub 2024 Aug 26.
Freeze-thaw (FT) aging can change the physicochemical characteristics of microplastics (MPs). The toxic impacts of FT-aged-MPs to soil invertebrates are poorly understood. Here the toxic mechanisms of FT-aged-MPs were investigated in earthworms after 28 d exposure. Results showed that FT 50 µm PE-MPs significantly increased reactive oxygen species (ROS) by 5.78-9.04 % compared to pristine 50 µm PE-MPs (41.80-45.05 ng/mgprot), whereas FT 500 µm PE-MPs reduced ROS by 7.52-7.87 % compared to pristine 500 µm PE-MPs (51.44-54.46 ng/mgprot). FT-PP-MPs significantly increased ROS and malondialdehyde (MDA) content in earthworms by 14.82-44.06 % and 46.75-110.21 %, respectively, compared to pristine PP-MPs (40.56-44.66 ng/mgprot, 0.41-2.53 nmol/mgprot). FT-aged PE- and PP-MPs caused more severe tissue damage to earthworms. FT-aged PE-MPs increased the alpha diversity of the gut flora of earthworms compared to pristine MPs. Earthworm guts exposed to FT-aged-MPs were enriched with differential microbial genera of contaminant degradation capacity. FT-PE-MPs affected membrane translocation by up-regulating lipids and lipid-like molecules, whereas FT-PP-MPs changed xenobiotic biodegradation and metabolism by down-regulating organoheterocyclic compounds compared to the pristine PE- and PP-MPs. This study concludes that FT-aged MPs cause greater toxicity to earthworms compared to pristine MPs.
冻融（FT）老化会改变微塑料（MPs）的物理化学特性。FT 老化 MPs 对土壤无脊椎动物的毒性影响尚未可知。本研究在 28 天暴露后，研究了 FT 老化 MPs 对蚯蚓的毒性机制。结果表明，与原始 50µmPE-MPs（41.80-45.05ng/mgprot）相比，FT50µmPE-MPs 显著增加了活性氧（ROS），增加了 5.78-9.04%，而 FT500µmPE-MPs 则减少了 7.52-7.87%，与原始 500µmPE-MPs（51.44-54.46ng/mgprot）相比。与原始 PP-MPs（40.56-44.66ng/mgprot，0.41-2.53nmol/mgprot）相比，FT-PP-MPs 使蚯蚓体内 ROS 和丙二醛（MDA）含量分别增加了 14.82-44.06%和 46.75-110.21%。FT 老化的 PE 和 PP-MPs 对蚯蚓造成的组织损伤更为严重。FT 老化的 PE-MPs 增加了蚯蚓肠道菌群的 alpha 多样性，而原始 MPs 则没有。暴露于 FT 老化 MPs 的蚯蚓肠道中富含具有污染物降解能力的差异微生物属。FT-PE-MPs 通过上调脂质和类脂分子影响膜转位，而 FT-PP-MPs 通过下调有机杂环化合物改变外来生物的生物降解和代谢，与原始的 PE 和 PP-MPs 相比。本研究得出结论，FT 老化的 MPs 比原始 MPs 对蚯蚓造成更大的毒性。
