土壤中环境持久性自由基的形成与稳定及其影响因素

Formation,stability and influencing factors of environmentally persistent free radicals in soil:a review

环境持久性自由基(EPFRs)是一类具有环境风险的新型污染物,因其广泛分布于环境中且具有潜在环境毒性效应而受到关注。虽然研究者们已发现天然土壤与受有机污染物污染的土壤(如多环芳烃、五氯苯酚等)中均存在非常稳定的EPFRs,但对于这两种环境条件下EPFRs的生成、稳定、影响因素的相关结论仍然存在争论。本文综述了天然土壤组分(腐殖质、有机-无机复合体)中EPFRs的分布特征、形成机理与影响因素,并论述有机污染物降解过程中EPFRs的生成、稳定机制及迁移转化,总结出不同因素(土壤有机质、过渡金属、氧气、湿度、温度)对EPFRs的影响。本文加深了对土壤中EPFRs环境行为的认识,并对腐殖质中EPFRs的研究进行了展望,对土壤环境中EPFRs的进一步研究提供参考。

Environmentally persistent free radicals(EPFRs)are known as a new type of emerging environmental contaminants.They have received broad research attentions due to their wide distribution in environment and high potential of environmental toxic effects.Although these very stable EPFRs have been identified in both natural soil and the soil contaminated with organic compounds such as polycyclic aromatic hydrocarbons and pentachlorophenol.The formation mechanisms,stability and influence factors of EPFRs under these two environmental conditions are quite different.In this paper,the formation and distribution of EPFRs in nature soil components(such as humic substances and organo-mineral complexes)were reviewed and the reasons why the organic compounds of degradation process could promote the formation,stability,migration,transformation of EPFRs,the environmental factors(including soil organic matter,transition metals,oxygen,humidity,and temperature)could influence on EPFRs generation were also summarized.In general,this review aims to provide a comprehensive understanding on EPFRs formation mechanisms and stability in soil,and provide a basic foundation on EPFRs in soil environment.