土壤中全氟和多氟烷基化合物的污染现状及环境行为

Current Pollution Status and Environmental Behaviors of PFASs in Soil

全氟和多氟烷基化合物(perfluoroalkyl and polyfluoroalkyl substances,PFASs)是一类新兴持久性有机污染物.土壤中PFASs可以通过淋溶作用进入地下水影响水质安全,或者通过陆生食物链的传递和生物放大作用危害生态系统和人类健康,有关土壤中PFASs的赋存状况、浓度水平与行为机制的研究已经成为环境化学领域的热点之一.目前土壤中可以准确测定的PFASs在含氟化合物总量中的占比不到1%,含量为ng g水平.我国相关研究主要集中在东部及氟化工厂周边地区,其组分以全氟辛烷磺酸(Perfluorooctane sulfonic acid,PFOS)和全氟辛酸(Perfluorooctanoic acid,PFOA)等长链PFASs为主.不同类型土壤中PFASs的赋存特征主要受到物质种类与土壤理化性质及周边人类活动的影响.除了含氟化学品生产和使用过程中的直接释放和大气传输以外,PFASs前体物在土壤环境中的转化也是其重要来源.吸附-解吸是PFASs在土壤中的主要归趋方式,化合物碳链长度及官能团种类、土壤理化性质和生物种类等因素都会影响其在土壤中的迁移转化和富集能力.鉴于目前的研究现状,需要进一步优化土壤中PFASs的提取和分析方法,关注新型PFASs在土壤中的变化趋势及行为机制,开展土壤中PFASs的生物可给性和生物可利用性研究,进一步评估PFASs的生态与人体健康风险.

Perfluoroalkyl and polyfluoroalkyl substances(PFASs)are a group of emerging persistent organic pollutants.PFASs in soil can affect water quality when they leach into groundwater,and threaten the ecosystem and human health through trophic transfer and magnification along the terrestrial food chains,which make them one of the hot research topics in environmental chemistry.At present,the content of less than 1%of the total fluorinated compounds in the soil can be accurately determined,and the content is at the ng g level.The research areas in China are concentrated in the east and the surrounding areas of fluorochemical plants.The main compounds of PFASs in soil are PFOS and PFOA.The physicochemical properties of soil,species of PFASs and human activities are the main factors influencing the occurrence of PFASs in different types of soil.In addition to the direct release and atmospheric transport during the production and use of fluorinated chemicals,PFASs precursor conversion in soil is also an important source of PFASs.Adsorption-desorption is the major process affecting the transport of PFASs in soil.Studies also demonstrate that the transport and accumulation of PFASs in soil are affected by various factors such as the chain-length and functional groups of PFASs,soil physicochemical properties and microorganisms.In consideration of the research status,further development of extraction and analytical methods is needed to cover a wider range of PFASs.Attention can be paid to the changing trend and mechanism of novel PFASs in soil.The bioaccessibility and bioavailability study of PFASs in soil are also needed for ecological and human health risk assessment.