项目名称: 土壤中多溴联苯醚的植物吸收及根际降解行为与机理
项目编号: No.20807048
项目类型: 青年科学基金项目
立项/批准年度: 2009
项目学科: 化学工业
项目作者: 黄红林
作者单位: 中国科学院生态环境研究中心
项目金额: 20万元
中文摘要: 多溴联苯醚(PBDEs)是全球广泛使用的添加型阻燃剂,易在土壤和沉积物等环境介质中累积。目前有关PBDEs在陆生生态环境行为研究还非常有限,特别是在土壤-植物系统中迁移转化的研究还鲜见有报道。本项目采集电子垃圾倾泻点PBDEs实际污染土壤,利用温室盆栽实验研究了PBDEs的植物吸收与累积特性以及土壤降解规律;采用温室水培实验,研究了典型PBDEs单体的植物体内传输特征和降解行为;以BDE-209为研究对象,研究了植物组成与植物吸收BDE-209之间的关系,探讨了土壤中PBDEs的根际降解效应以及代谢行为。结果表明PBDEs能够被植物吸收且存在由根向茎的传输;植物显著促进土壤中PBDEs的降解且低溴代PBDEs降解率大于高溴代PBDEs。亲脂性较强的PBDEs较易富集在根中,但较难向上传输;脱溴降解在植株各个部位普遍存在。植物根对BDE-209的吸收以及传输因子均与根脂的含量呈一定相关关系;BDE-209在土壤-植物系统存在脱溴和羟基化代谢;土壤微生物对BDE-209在根际微域的降解起重要作用。本研究对于认识PBDEs的陆生生态环境行为,评价其生态风险以及对食物链的暴露风险有重要意义。
中文关键词: 土壤;多溴联苯醚;植物吸收;降解;机理
英文摘要: Polybrominated diphenyl ethers (PBDEs) are used widely around the world as a kind of additive flame retardants. They are prone to accumulate in the environmental media, such as soil and sediment. However, researches on PBDE behaviors in the terrestrial environment are very limited. Especially, reports on PBDE transformation in the soil-plant system are scarce. In this study, a greenhouse experiment was conducted to investigate plant uptake and fate of PBDEs in the soils of e-waste recycling sites, and then to explore the process of uptake and translocation of PBDE congeners in plants as well as their debromination. The behavior of BDE-209 in the soil-plant system was studied and rhizosphere effects on PBDE degradation were evaluated. Weathered PBDEs in the soils are bioavailable for plant uptake and they can be translocated from the roots to the aboveground parts. Lower brominated PBDEs were more readily available for plant uptake than the higher brominated PBDEs. Planting significantly enhanced dissipation of PBDEs in the soils and lower brominated PBDEs were associated with higher dissipation rates. Higher brominated PBDEs, which are of higher lipophilicity, have a stronger uptake capability but were translocated with more difficulty. Debromination of PBDEs occurred in all parts of plant. Root uptake and translocation factor of BDE-209 were related to root lipid content. Debromination and hydroxylation of BDE-209 were observed in the soil-plant system. Microbial metabolism and degradation contribute to BDE-209 dissipation in soil. Studies on this process would shed light on assessing the bioavailability of PBDEs and their ecological risks, as well as providing information for behavior of PBDEs in the terrestrial environment.
英文关键词: Soil; PBDEs; plant uptake; degradation; mechanism