土壤中微塑料:类型、载体效应、迁移行为和潜在风险综述

Microplastics in soils:a review of types,carrier effects,migration behavior,and potential risks

微塑料(microplastics,MPs)作为一种新兴污染物,广泛存在于土壤中,并不断迁移转化,对土壤生态系统和生物多样性产生潜在风险。为了全面评估土壤MPs的环境风险,加强MPs污染的风险管控,讨论了土壤环境中MPs的类型,系统阐述了土壤MPs的载体效应和迁移行为,并从微生物、植物、动物以及人类四个方面综述了土壤MPs的潜在风险。土壤中MPs并不是单独存在的,MPs的潜在风险一方面来自其本身(颗粒和添加剂)的生物毒性,另一方面是其对共存污染物(有机污染物、重金属和致病菌等)的载体效应。在非生物(淋溶、重力)和生物等作用下,土壤中的MPs时刻都在经历着复杂的迁移过程,从而加剧了其对土壤生态系统的影响。由于粒径小,MPs很容易进入食物链并层层传递,从而对不同营养级生物的正常生理活动产生不利影响,包括影响土壤动植物的新陈代谢,生长,发育和繁殖。此外,MPs不仅在环境中存在,而且也在人体中被发现。MPs可通过饮食、呼吸或皮肤接触等途径进入人体,从而对人体可能产生一系列不良反应。虽然目前仍没有足够的证据证明MPs对人体的直接危害,但其潜在风险仍不容忽视。探讨了土壤MPs污染治理的策略,并对未来土壤微塑料污染的研究方向和重点进行了展望。研究将有助于加深人们对土壤微塑料污染的认识,并为更好地开展微塑料的毒理效应研究和风险评估提供科学线索和理论参考。

Microplastics(MPs),as an emerging class of pollutants has become a global concern,and is receiving increasing attention.MPs are considered ubiquitous in soil ecosystems and continuous migration and transformation,which generates the potential risk on soil ecosystems and biodiversity.In order to comprehensively assess the environmental risk of MPs in soil and strengthen the risk control of MPs pollution,the types of MPs in the soil environment were discussed in detail,and the carrier effect and migration behavior of MPs from soil were systematically elaborated in this paper as well.In addition,we performed a systematic literature review to identify the potential risk of MPs in soil from four perspectives:microorganism,plant,animal,and human.The MPs did not exist independently,and on coexist with other contaminants in the soil environment.On the one hand,toxicity of MPs can be caused by the plastic polymers themselves,the particles or by the additives they contain.On the other hand,MPs are potential carriers of some hazardous substances,such as persistent organic pollutants,heavy metals,antibiotic resistance genes,and pathogenic microorganisms.MPs in soil inevitably undergo complex aging transformation and transport process all the time under the effect of either biotic(e.g.plant growth and the daily activity of animals)or abiotic(e.g.leaching and gravity)processes.As a result,contamination of soils by MPs further exacerbates the effects on the soil ecosystem.Because of their small grain size,MPs can easily enter into the food chain and transmit them layer by layer,thus adversely affecting the normal physiological activities of organisms at different trophic levels,including affecting the metabolism,growth,development and reproduction of soil animals and plants.Furthermore,MPs have not only been found in the environment,but also in the human body.MPs can enter the body through various routes,including dietary intake,breathing inhalation,and skin contact,which may cause a series of side effects on human health.Although there is still inadequate evidence to prove the direct harm of MPs to human body,their potential risk should not be ignored.Finally,we explored the strategies for the management of soil MPs pollution,and provided a perspective on future research directions and priorities for soil MPs pollution.This comprehensive review will help to deepen the understanding of soil MPs pollution,and at the same time provides valuable scientific clues and theoretical references for a better carrying out toxicological research and risk assessment of soil MPs pollution.