植物对卤代有机污染物吸收、迁移和代谢的研究进展

摘要

The environmental risks of halogenated organic pollutants (HOPs) have attracted considerable research interest due to their persistence, long range transport, bioaccumulation, and toxicity. Plants are important reservoirs of pollutants in environment and play key role in trapping and transferring airborne pollutants to terrestrial ecosystems. Research on the bioaccumulation, translocation, and transformation of HOPs in plant is critically important to understand the behavior, evaluate the potential risks to ecological system, and phytoremediation of HOPs. This review summarized the recent data on the absorption and bioaccumulation of HOPs in plants. The absorption and translocation behaviors of HOPs from the atmosphere, soil, and water to the plants, and the metabolism and transformation of HOPs in plants were also reviewed. The key factors affected the bioaccumulation, translocation, degradation and transformation of HOPs in plants were discussed. Results of research showed that the key factors affected the bioaccumulation of HOPs in plants were octanol-air partition coefficient (KOA) and octanol-water partition coefficient (Kow). The values of root concentration factors (RCFs) were higher when the values of log Kow of compounds ranged from 6 to 8. The lipid content in plants, physicochemical property of compounds, and environmental media were the important factors affected the translocation of HOPs in plants. Dehalogenation was the primary degradation pathway of HOPs in plants, and methoxylation and hydroxylation are two major transformation ways. The soil bacteria with the genes of dehalogenation reductase, nitrate reductase (NaR) and glutathione S-transferases (GST) could effectively promote degradation and metabolism of HOPs in plants. Although these studies have made some progress, the research on the bioaccumulation, translocation, degradation and transformation of HOPs in plants were still in their infancy. The mechanism of bioaccumulation, translocation, and metabolism of new HOPs in plants and the phytoremediation technology applied on the decreasing of environmental toxicity of HOPs were discussed and prospected.%卤代有机污染物（Halogenated organic pollutants，HOPs）在环境中具有持久性、长距离迁移性、生物积累性和潜在的生物毒性等特点，HOPs所引起的环境问题已成为全球环境科学研究热点。植物是环境介质中各种污染物的重要存储体，也是各类污染物进入陆生食物链的重要途径。研究植物对HOPs的吸收、传输与转化特征，对明确HOPs的环境行为、生态风险评价及植物修复等都具有重要的意义。文章在总结了近年来国内外关于植物对HOPs累积研究的基础上，综述了植物对大气、土壤和水体中HOPs的吸收和传输特征、HOPs在植物体内的迁移特征和代谢转化途径，分析了影响HOPs在植物中的积累、传递、降解与转化行为的主要因素。研究表明，辛醇-空气分配系数（Octanol-air partition coefficient，KOA）和辛醇-水分配系数（Octanol-water partition coefficient，Kow）是影响植物吸收HOPs的关键因素，当化合物的log Kow值在6~8的范围内时，植物根系对HOPs的根系富集因子（Root concentration factors，RCFs）较高；植物体内的脂质含量、化合物的理化性质和环境介质的差异是影响HOPs在植物体内传输的重要因素；脱卤代原子是植物降解HOPs的主要途径，而甲氧基化和羟基化是HOPs在植物体内转化的主要模式，具有还原脱卤酶基因的土壤细菌和植物体内的硝酸还原酶（NaR）与谷胱甘肽硫转移酶（GST）能有效促进植物对HOPs的降解代谢。这些研究虽然都取得了一定的进展，但关于植物对HOPs积累迁移与代谢转化的研究仍处于起步阶段，文章就新型HOPs在植物体内积累、传输与代谢机制及采用植物修复技术降低HOPs的环境毒性等方面进行了讨论和展望。