Sichuan Agricultural University, College of Resources, Chengdu, 611130, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, China.
Tongji University, State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Shanghai, 200092, China.
Environ Pollut. 2022 Sep 1;308:119718. doi: 10.1016/j.envpol.2022.119718. Epub 2022 Jul 6.
Microplastic pollution is a recognized hazard in aquatic systems, but in the past decade has emerged as a pollutant of interest in terrestrial ecosystems. This paper is the first formal meta-analysis to examine the phytotoxic effects of microplastics and their impact on soil functions in the plant-soil system. Our specific aims were to: 1) determine how the type and size of microplastics affect plant and soil health, 2) identify which agricultural plants are more sensitive to microplastics, and 3) investigate how the frequency and amount of microplastic pollution affect soil functions. Plant morphology, antioxidant production and photosynthesis capacity were impacted by the composition of polymers in microplastics, and the responses could be negative, positive or neutral depending on the polymer type. Phytotoxicity testing revealed that maize (Zea mays) was more sensitive than rice (Oryza sativa) and wheat (Triticum aestivum) within the Poaceae family, while wheat and lettuce (Lactuca sativa) were less sensitive to microplastics exposure. Microplastics-impacted soils tend to be more porous and retain more water, but this did not improve soil stability or increase soil microbial diversity, suggesting that microplastics occupied physical space but were not integrated into the soil biophysical matrix. The meta-data revealed that microplastics enhanced soil evapotranspiration, organic carbon, soil porosity, CO flux, water saturation, nitrogen content and soil microbial biomass, but decreased soil NO flux, water stable aggregates, water use efficiency, soil bulk density and soil microbial diversity.
微塑料污染是水生系统中公认的危害，但在过去十年中，它已成为陆地生态系统中受到关注的污染物。本文是首次正式的荟萃分析，旨在研究微塑料的植物毒性效应及其对植物-土壤系统中土壤功能的影响。我们的具体目标是：1）确定微塑料的类型和大小如何影响植物和土壤健康；2）确定哪些农业植物对微塑料更敏感；3）研究微塑料污染的频率和数量如何影响土壤功能。微塑料中聚合物的组成影响植物形态、抗氧化剂的产生和光合作用能力，其响应可能是负面的、正面的或中性的，这取决于聚合物的类型。植物毒性测试表明，禾本科植物中的玉米（Zea mays）比水稻（Oryza sativa）和小麦（Triticum aestivum）更敏感，而小麦和生菜（Lactuca sativa）对微塑料暴露的敏感性较低。受微塑料影响的土壤往往更具多孔性和保水性，但这并没有提高土壤稳定性或增加土壤微生物多样性，表明微塑料占据了物理空间，但并未融入土壤生物物理基质。元数据分析表明，微塑料增强了土壤蒸散、有机碳、土壤孔隙度、CO 通量、水分饱和度、氮含量和土壤微生物生物量，但降低了土壤 NO 通量、水稳定团聚体、水分利用效率、土壤容重和土壤微生物多样性。
