College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China.
Key Laboratory of Cryospheric Science and Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Donggang West Rd. 318, Lanzhou 730000, China.
Environ Pollut. 2024 Nov 1;360:124630. doi: 10.1016/j.envpol.2024.124630. Epub 2024 Jul 28.
As an emergent pollutant, microplastics (MPs) are becoming prevalent in the soil environment. However, the characteristics of MPs and the response of microbial communities to the abundance of MPs in agricultural soils in West China still need to be elucidated in detail. This study utilized the Agilent 8700 Laser Direct Infrared (LDIR) to analyze the characteristics of small-sized MPs (20-1000 μm) in soils from un-mulched and mulched agricultural fields in West China, and illustrated their correlation with microbial diversity. The results revealed a higher abundance of MPs in mulched soil ((4.12 ± 2.13) × 10 items kg) than that in un-mulched soil ((1.04 ± 0.26) × 10 items kg). The detected MPs were dominated by fragments, 20-50 μm and Polyamide (PA). High-throughput sequencing analysis indicated that alpha diversity (Chao1 and Shannon indices) in the plastisphere was lower compared to that in soil, and varied significantly with MPs abundance in soil. As the abundance of MPs increased, the proportion of soil about the degradation of organic matte and photoautotrophic taxa increased, which showed enrichment in the plastisphere. Functional predictions further indicated that MPs abundance affected potential soil functions, such as metabolic pathways associated with the C and N cycling. The plastisphere showed higher functional abundance associated with organic matter degradation, indicating higher potential health risks compared to soil environments. Based on the RDA analyses, it was determined that environmental physicochemical properties and MPs abundance had a greater impact on fungal communities than on bacterial communities. In general, the abundance of MPs affected the microbial diversity composition and potentially influenced the overall performance of soil ecosystems. This study offers empirical data on the abundance of MPs in long-term mulched agricultural fields and new insights for exploring the ecological risk issues associated with MPs.
作为一种新兴污染物，微塑料（MPs）在土壤环境中越来越普遍。然而，在中国西部农业土壤中 MPs 的特征以及微生物群落对 MPs 丰度的响应仍需要详细阐明。本研究利用安捷伦 8700 激光直接红外（LDIR）分析了中国西部未覆膜和覆膜农业土壤中小尺寸 MPs（20-1000μm）的特征，并说明了它们与微生物多样性的相关性。结果表明，覆膜土壤中的 MPs 丰度（（4.12±2.13）×10 items kg）高于未覆膜土壤中的 MPs 丰度（（1.04±0.26）×10 items kg）。检测到的 MPs 主要为碎片、20-50μm 和聚酰胺（PA）。高通量测序分析表明，与土壤相比，塑料圈的 alpha 多样性（Chao1 和 Shannon 指数）较低，并且与土壤中 MPs 的丰度差异显著。随着 MPs 丰度的增加，与有机 matte 降解和光自养分类群有关的土壤比例增加，在塑料圈中表现出富集。功能预测进一步表明， MPs 丰度影响了潜在的土壤功能，如与 C 和 N 循环相关的代谢途径。塑料圈显示出与有机物降解相关的更高功能丰度，表明与土壤环境相比，其具有更高的潜在健康风险。基于 RDA 分析，确定环境物理化学性质和 MPs 丰度对真菌群落的影响大于对细菌群落的影响。总的来说， MPs 的丰度影响了微生物多样性的组成，并可能影响土壤生态系统的整体性能。本研究为长期覆膜农业土壤中 MPs 的丰度提供了经验数据，并为探索与 MPs 相关的生态风险问题提供了新的见解。
