本项目拟以2种典型溴代阻燃剂(四溴双酚A和2,4,6-三溴苯酚)及1种四溴双酚A的还原脱溴产物双酚A为研究对象，利用溴代阻燃剂污染的河流沉积物上覆天然水体模拟研究其在天然好氧/厌氧条件下生物降解转化过程，利用单体稳定同位素分析(CSIA)技术结合产物分析鉴定，阐明其在天然沉积物中的生物降解转化机制，单体稳定Br同位素直接示踪Br官能团的生物转化途径。同时，研究其生物降解过程中13C、2H和81Br同位素富集变化特征，获得稳定C、H和Br同位素富集因子。利用该富集因子，CSIA技术实现对地下水体沿羽流方向的典型溴代阻燃剂的原位生物降解和非生物转化进行定性和定量评估。本项目的成功实施不仅为研究典型溴代阻燃剂的环境迁移、转化和原位生物降解程度的量化等提供直接可靠的证据，而且为研究环境中其他溴代阻燃剂以及含溴化合物的迁移、转化与归趋提供参考的生物降解稳定C、H和Br同位素富集因子及科学的研究方法。

The biodegradation of two typical brominated flame retardants (tetrabromobisphenol A and 2,4,6-tribromophenol) and one reductive debromination product of tetrabromobishphenol A (bisphenol A) by natural microbe under aerobic/anaerobic conditions will be studied using a laboratory microcosm system with natural sediments contaminated with brominated flame retardants overlying with natural water. Compound-specific stable isotope analysis (CSIA) can be used to characterize the 13C, 2H and 81Br isotope enrichments of the three residual target compounds. Combined with the analyses of the products, the biodegradation and transformation mechanism in natural sediments will be illustrated. Bromine isotope analyses will also be performed to investigate the biodegradation and transformation mechanism. Furthermore, the stable isotope enrichment factors for C, H and Br are used to assess the in situ biodegradation of the three target compounds. In addition, the obtained stable isotope signatures are used to quantify the relative extent of biodegradation of brominated flame retardants along the contaminant plume with brominated flame retardants with the Rayleigh equation. On the basis of this project, the characteristic isotope patterns may not only significantly add to the present understanding of the environmental source, transformation, degradation, and fate of brominated flame retardants, but also provide C, H and Br isotope enrichment factors of the biodegradation process for reference.