典型污灌区土壤-地下水系统中胶体态多溴联苯醚传输过程的同位素指纹识别

Protection of soil-groundwater system in the sewage irrigation areas is an important and strategic issue closely related to food,water and ecological security.This study noticed that this system is not only the major accumulation area of the emerging global persist pollutants of polybrominated diphenyl ethers (PBDEs), but also a blank and complicated field of PBDEs study. To identify their complex processes in soil- groundwater system, sewage irrigation area of Xiaodian in Taiyuan is selected as the study area, the source, migration and transformation processes of PBDEs are used as research line, compound specific isotope analysis of organic bromide (CSIA-OBr) is used as the key technology, laboratory and field experiments are conducted to analyze interactions between colloid, microorganism and PBDEs in soil-groundwater system, as well as bromine isotopic fractionation effects of brominated organic compounds (BOCs) under four conditions of no degradation, abiotic degradation, aerobic and anaerobic biodegradation. Based on these, this study is expected to establish an identity system of CSIA-OBr for colloidal PBDEs transport process in soil-groundwater system, a database of bromine isotopic compositions of PBDEs and their degradation products, and identification criterions of the source, migration path and degradation types using CSIA-OBr. This study will be helpful for further understanding PBDEs behavior in the environment, and provide a new way of effectively preventing and controlling soil-groundwater system pollution caused by PBDEs in sewage irrigation areas.

污灌区土壤-地下水系统保护是涉及粮食、饮水和生态安全的战略问题。本研究基于该系统是多溴联苯醚（PBDEs）这一全球新兴持久性污染物的主要汇集区，也是PBDEs研究的空缺区和难点聚集区，以太原市小店污灌区为研究区，以PBDEs的来源、迁移、转化过程为主线，以有机单体溴同位素分析(CSIA-OBr)为关键技术，分别从无降解、非生物降解、好氧型和厌氧型生物降解4个层面开展土壤-地下水系统中胶体或颗粒物、微生物与PBDEs相互作用及其CSIA-OBr分馏效应的室内与野外研究，识别污灌区土壤-地下水系统中CSIA-OBr对PBDEs传输、迁移和生物转化过程的指示意义，有望建立PBDEs同系物及其降解产物的有机单体溴同位素组成数据库，建立CSIA-OBr示踪PBDEs的污染来源、迁移途径、降解类型的同位素模型。本研究为更全面深入地认识PBDEs的环境行为，有效防治污灌区土壤-地下水系统的PBDEs污染，提供了新途径。

污灌区土壤-地下水系统保护是涉及粮食、饮水和生态安全的战略问题。本研究基于该系统是多溴联苯醚（PBDEs）这一全球新兴持久性污染物的主要汇集区，也是 PBDEs研究的空缺区和难点聚集区，以太原市小店污灌区为研究区，以土壤-地下水系统中PBDEs含量以及单体溴和碳同位素测试技术为突破点，以胶体、微生物与PBDEs的相互作用过程为主线，建立了地下水中PBDEs迁移转化碳、溴二维同位素识别体系。本项目突破了三项关键测试技术，揭示了2个基本过程，概括为三项标志性成果如下：（1）三项关键测试技术：水体中PBDEs的荧光光谱分析法、顶空-固相微萃取-气相色谱-燃烧炉-同位素质谱测定水样中BDE-47单体碳同位素组成、基于气相色谱-四级杆质谱的水样中BDE-47单体溴同位素测试，实现了简单快速测定；（2）土壤-地下水系统中胶体和微生物对PBDEs迁移的影响表征：阐明了胶体和微生物对PBDEs的作用机理，极大的提高了土壤-地下水系统中PBDEs迁移理论水平；（3）PBDEs单体碳、溴同位素效应及指示：建立了PBDEs碳溴同位素数据库，并识别出原料和工艺会导致PBDEs单体碳溴同位素变化，可用于污染源识别。该成果已纳入《地下水污染源同位素解析技术指南（建议稿）》，推动了我国有机单体同位素在有机污染源解析中的应用。本研究为更全面深入地认识 PBDEs 的环境行为，有效防治污灌区土壤-地下水系统的PBDEs 污染，提供了新思路。