生物和非生物因素对蚯蚓驱动土壤中微塑料垂向迁移的影响研究

    Effects of Biotic and Abiotic Factors on the Vertical Migration of Microplastics in Soil Driven by Earthworms

    • 摘要: 微塑料作为一种新污染物,其污染已成为全球广泛关注的热点环境问题。农田土壤中微塑料污染对食物链和陆生生态系统构成了潜在威胁。本文通过中宇宙试验装置,模拟了农田土壤中不同生物因素(跳虫、蚯蚓密度、植物根系)和非生物因素(微塑料的类型和老化、暴露时间、淹水)的变化,探索了上述变化对蚯蚓驱动土壤中微塑料垂向迁移的影响。结果表明,微塑料的垂向迁移量随土壤深度的增加而减少;跳虫的存在和蚯蚓密度的增大对土壤中微塑料垂向迁移产生积极影响;植物根系的生长则倾向于将微塑料保留在表层土壤,从而减少蚯蚓对微塑料的垂向迁移;不同微塑料类型对其在土壤中的垂向迁移影响由大到小依次为聚乙烯(PE)、聚苯乙烯(PS)和聚对苯二甲酸乙二醇酯(PET);短期老化未影响蚯蚓垂向迁移土壤中微塑料;随着暴露时间的增加,更多的微塑料垂向迁移到深层土壤中;淹水可促进土壤中微塑料的垂向迁移。该研究揭示了蚯蚓驱动土壤中微塑料的垂向迁移规律与影响因素,为认识农田土壤中微塑料的迁移规律提供了科学依据。

       

      Abstract: As a new pollutant, microplastics pollution has become a global environmental issue. Agricultural soils contaminated with microplastics pose a potential threat to the food chain and terrestrial ecosystems. This study utilized a mesocosm device to simulate changes of different biotic (springtail, earthworm density, plant roots) and abiotic (type and aging of microplastics, exposure time, flooding) factors in agricultural soils and explored their effects on the vertical migration of microplastics in the soil driven by earthworms. Results show that the vertical migration of microplastics decreased with increasing soil depth, and was positively influenced by springtail and high densities of earthworms. The growth of plant roots tended to retain microplastics in the surface soil layer and reduce the vertical migration of microplastics by earthworms. The type of microplastics also had an impact on vertical migration in the order of PE > PS > PET. Short-term aging had no significant effect on the vertical migration of microplastics in soil, but exposure time and flooding promoted the migration of microplastics to deeper soil layers. This study provides a scientific basis for understanding the vertical migration patterns and influencing factors of microplastics in agricultural soils under earthworm activities.

       

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