Key Laboratory of Wet 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 Wet 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.
Sci Total Environ. 2024 Mar 20;917:170541. doi: 10.1016/j.scitotenv.2024.170541. Epub 2024 Jan 28.
Microplastics (MPs) can co-occur widely with heavy metals in soil. This study intended to investigate the influences of the co-exposure of polyethylene MPs (0.5 %, w/w) and cadmium (Cd) in black soil on the Cd distribution, enzyme activities, and bacterial communities in both bulk soil and different sized soil aggregates (> 1, 0.50-1, 0.25-0.50, and < 0.25 mm aggregates) after a 90-day incubation. Our results showed that the existence of MPs increased the distributions of Cd in >1 mm and < 0.25 mm soil aggregates and decreased its distributions in 0.50-1 mm and 0.25-0.50 mm soil aggregates. About 12.15 %-17.65 % and 9.03 %-11.13 % of Cd were distributed in the exchangeable and oxidizable forms in bulk soil and various sized soil aggregates after the addition of MPs which were higher than those in the only Cd-treated soil (11.17 %-14.72 % and 8.66 %-10.43 %, respectively), while opposite tendency was found for Cd in the reducible form. Urease and β-glucosidase activities in the Cd-treated soils were 1.14-1.18 and 1.07-1.31 times higher than those in the Cd-MPs treated soils. MPs disturbed soil bacterial community at phylum level and increased the bacteria richness in bulk soil. The levels of predicted functional genes which are linked to the biodegradation and metabolism of exogenous substances and soil C and N cycles were altered by the co-exposure of Cd and MPs. The findings of this study could help deepen our knowledge about the responses of soil properties, especially microbial community, to the co-occurrence of MPs and heavy metals in soil.
微塑料（MPs）可以与土壤中的重金属广泛共存。本研究旨在探讨聚乙烯 MPs（0.5%，w/w）和镉（Cd）在黑土中共同暴露对土壤中 Cd 分布、酶活性和不同粒径土壤团聚体（>1、0.50-1、0.25-0.50 和<0.25 mm 团聚体）中细菌群落的影响。结果表明，MPs 的存在增加了>1mm 和<0.25mm 土壤团聚体中 Cd 的分布，减少了 0.50-1mm 和 0.25-0.50mm 土壤团聚体中 Cd 的分布。添加 MPs 后，约 12.15%-17.65%和 9.03%-11.13%的 Cd 分布在土壤和不同粒径土壤团聚体的可交换态和可氧化态，高于仅添加 Cd 的土壤（分别为 11.17%-14.72%和 8.66%-10.43%），而 Cd 的还原态则相反。添加 MPs 后，Cd 处理土壤中的脲酶和β-葡萄糖苷酶活性分别比 Cd-MPs 处理土壤高 1.14-1.18 倍和 1.07-1.31 倍。MPs 在门水平上干扰了土壤细菌群落，并增加了土壤的细菌丰富度。与外源性物质和土壤 C、N 循环的生物降解和代谢相关的预测功能基因的水平因 Cd 和 MPs 的共同暴露而发生改变。本研究的结果可以帮助我们更深入地了解土壤性质，特别是微生物群落对土壤中 MPs 和重金属共存的响应。
