聚乙烯和聚乳酸微塑料对蚯蚓的毒性效应

Toxicological effects of polyethylene and polylactic acid microplastics on earthworms

微塑料对土壤动物的生态毒性被广泛认知,但多数研究关注的是传统难降解微塑料,如聚乙烯(polyethylene,PE)等.可生物降解微塑料对土壤动物的毒性效应知之甚少.通过室内暴露试验,比较研究了不同浓度(1%和10%,w/w)PE微塑料和可生物降解聚乳酸(polylacticacid,PLA)微塑料对赤子爱胜蚓(Eiseniafetida)的生态毒性.结果表明,与对照相比,PE和PLA处理均会导致蚯蚓体重损失和一定的死亡率(22%-24%).PE和PLA均会诱导蚯蚓发生氧化应激反应:超氧化物歧化酶(SOD)活性增加,过氧化物酶(CAT)和谷胱甘肽硫转移酶(GST)活性降低.组织病理学分析表明,PLA比PE表现出更严重的表皮损伤、肠道损伤和精囊损伤,高浓度时效应更为显著.本研究表明,传统难降解微塑料和可生物降解微塑料均可对蚯蚓产生毒性效应,可降解微塑料并不比传统微塑料更具有生态友好性.

The ecotoxicology of microplastics in soil fauna has been widely recognized,but most previous studies have focused on traditional non-degradable microplastics such as polyethylene(PE).Little is known about the toxicological effects of biodegradable microplastics on soil fauna.Using laboratory exposure experiments,we compared the ecotoxicological effects of PE and biodegradable polylactic acid(PLA)microplastics at concentrations of 1%and 10%(w/w)on earthworms(Eisenia fetida).The results showed that compared to the control treatment(no exposure to microplastics),exposure to PE or PLA led to higher weight loss and mortality(22%–24%)of earthworms.Both PE and PLA induced oxidative stress responses in earthworms,with higher superoxide dismutase(SOD)activity and lower catalase(CAT)and glutathione-S-transferase(GST)activity.Histopathological analysis showed that PLA caused more serious damage to the epidermis,intestinal tract,and seminal vesicles than PE,with more pronounced effects at a concentration of 10%.Our results show that both traditional and biodegradable microplastics can cause toxicological damage to earthworms,and biodegradable microplastics do not exhibit a greater degree of eco-friendliness than traditional microplastics.