Shao Xuechun, Liang Weiyu, Gong Kailin, Qiao Zhihua, Zhang Wei, Shen Genxiang, Peng Cheng
School of Resource and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.
State Environmental Protection Key Laboratory of Environmental Health Impact Assessment of Emerging Contaminants, Shanghai Academy of Environmental Sciences, Shanghai 200233, China.
Chemosphere. 2024 Dec;369:143822. doi: 10.1016/j.chemosphere.2024.143822. Epub 2024 Nov 28.
Biodegradable plastics (BPs) are regarded as ecomaterials and are emerging as a substitute for traditional non-degradable plastics. However, the information on the interaction between biodegradable microplastics (BMPs) and cadmium (Cd) in agricultural soil is still limited. Here, lettuce plants were cultured in BMPs (polylactic acid (PLA) MPs and poly(butylene-adipate-co-terephthalate) (PBAT) MPs) and Cd co-polluted soil for 35 days. The results show that diffusive gradient in thin films technique (DGT) but not diethylenetriaminepentaacetic acid (DTPA) extraction method greatly improved the prediction reliability of Cd bioavailability in non-rhizosphere soil treated with BMPs (R = 0.902). BMPs increased the Cd bioavailability in non-rhizosphere soil indirectly by decreasing soil pH, cation exchange capacity (CEC), and dissolved organic carbon (DOC), rather than by directly adsorbing Cd on their surface. PLA MPs incubated in rhizosphere soil showed more considerable degradation with extremely obvious cavities and the fracture of ester functional groups on their surface than PBAT MPs. BMPs could provide ecological niches to colonize and induce microorganisms associated with BMPs' degradation to occupy a more dominant position. In addition, Cd only affected the composition and function of microbial communities in soil but not on BMPs. However, co-exposure to BMPs and Cd significantly reduced the degrees of co-occurrence network of fungal communities on PLA MPs and PBAT MPs by 37.7% and 26.7%, respectively, compared to single exposure to BMPs.
可生物降解塑料（BPs）被视为生态材料，正逐渐成为传统不可降解塑料的替代品。然而，关于农业土壤中可生物降解微塑料（BMPs）与镉（Cd）之间相互作用的信息仍然有限。在此，将生菜植株种植在BMPs（聚乳酸（PLA）微塑料和聚己二酸-对苯二甲酸丁二醇酯（PBAT）微塑料）和Cd共同污染的土壤中35天。结果表明，薄膜扩散梯度技术（DGT）而非二乙烯三胺五乙酸（DTPA）提取方法极大地提高了BMPs处理的非根际土壤中Cd生物有效性的预测可靠性（R = 0.902）。BMPs通过降低土壤pH值、阳离子交换容量（CEC）和溶解有机碳（DOC）间接提高非根际土壤中的Cd生物有效性，而非通过直接在其表面吸附Cd。与PBAT微塑料相比，在根际土壤中孵育的PLA微塑料显示出更显著的降解，其表面有极其明显的空洞和酯官能团的断裂。BMPs可以提供生态位以供定殖，并诱导与BMPs降解相关的微生物占据更主导的地位。此外，Cd仅影响土壤中微生物群落的组成和功能，而不影响BMPs。然而，与单独暴露于BMPs相比，同时暴露于BMPs和Cd分别使PLA微塑料和PBAT微塑料上真菌群落的共现网络程度显著降低了37.7%和26.7%。
