土壤微塑料污染的生态效应

土壤环境中微塑料积累量大且不易降解，因此微塑料长期残留对土壤生态系统的影响已引起广泛关注。通过收集近年来有关土壤微塑料污染及其效应相关的文献，全面系统介绍了土壤微塑料积累后，土壤物理环境的变化、土壤动物摄入及其肠道微生物的响应、土壤微生物和土壤酶活性响应、以及植物对微塑料的吸收及其效应等方面的最新研究进展。现有研究结果表明:微塑料污染对土壤容重、团聚体组成和持水性等土壤物理性质有明显改变，而这些改变是影响土壤酶活性、微生物群落组成、甚至植物生长的关键因素。也有一些研究关注土壤无脊椎动物(如蚯蚓Lumbricus terrestris、跳虫Folsomia candida等)对微塑料在土壤中迁移的影响。同时，微塑料也会被这些土壤动物所摄食，并导致土壤动物体内肠道微生物群落组成的变化以及对其生长产生影响。此外，微塑料在陆地生态系统食物链中的积累及其效应也受到关注，比如，被蚯蚓摄食的微塑料可通过鸡Gallus gallus domesticus摄食蚯蚓进入鸡体内积累。在系统介绍土壤微塑料污染生态效应的研究进展基础上，结合微塑料组成与性质的复杂性以及当前研究的不足，提出4个未来研究方向:①建立土壤微塑料污染毒理学诊断的标准化方法体系；②研究土壤微塑料与微生物、植物和土壤动物之间的作用机理；③揭示微塑料与物质转化之间的关键微生物学机制；④开展不同土壤生态系统中的“塑料圈”研究。这些研究成果可为评估土壤微塑料污染的生态效应提供科学支撑。参80

Ecological effects of microplastics contamination in soils

Large amounts of microplastics have been accumulated in soils and their degradation is relatively slow. The residual time of microplastics in soils could be extended to decades or even over a hundred years. Therefore, the ecological effects of long-term residual of the microplastics in soils has been of concerned widely in recent years. Published papers related to the microplastics and their effects in soils were collected and introduced in order to make a full review in the field. The research advances were presented based on the different ecological receptors, which included change of soil physical environment due to the accumulation of microplastics, ingestion of microplastics by invertebrates from soils and their effects on the enteric microorganism, response of soil microbial community and soil enzyme to microplastics pollution, plant uptake of microplastics and their effects. The studies of effects on soil physical environment in the present of microplastics mainly focus on soil density, soil aggregate composition and water hold capacity. Such effects were supposed to have further impacts on soil enzyme activity, microbial community composition and even plant growth based on current limited studies. Many other studies at present were also concentrated on the migration of microplastics induced by soil invertebrates e.g. earthworm, springtail. Meanwhile, microplastics in the soil might be ingested by soil invertebrates and subsequently caused some negative effects and influence on the gut microorganism community of the soil invertebrates. There were also some studies focusing on the microplastics accumulation through food chain regarding the effects of microplastics on soil animals. For example, microplastics might be accumulated in chicken through the predation of earthworm by chicken. After the introduction of current studies, several research proposal were put forward based on the complication of microplastic’s properties and the shortage of current researches. These proposal contained four aspects: (1) development of standard protocols for the study of ecotoxicology of soil microplastics pollution, (2) studying the interaction mechanism between microplastics and microorganisms, plants and invertebrates, (3) revealing microbiological mechanisms that regulation of the transformation of materials and microplastics in soils, (4) exploring plastishere in soils of different ecosystems. All these researches are expected to be supportive to assessment of the ecological effects of soil microplastics pollution. Ch, 80 ref.]