十溴联苯醚在模式土壤中的加标老化及其老化机制研究

Deca-brominated diphenyl ether (BDE-209) is the largest used brominated flame retardants, its transfer/transform mechanism and bioavailability have been the heat issues in the research field of the organic pollutants. Many studies showed that, because of the adsorption effect of organic matters and aging, it was hard to get the mass balance during the microbiological degradation process of BDE-209 in soils or sediments. To solve this problem, this study seeks to simplify the degradation process from the complex soil matrix and concentrate on the adsorption effect.. We would firstly compose several kinds of model soils with different contains of total organic matters (TOCs), and characterize their TOCs,pH values and the field moisture capacity . And then study systematically on the aging process of BDE-209 in these composed model soils with two spiked concentrations by sterilized aging incubation under 25 ℃ and 80% of field moisture capacity,and simultaneously determine dynamics concentration changes of BDE-209 and the lower brominated diphenyl ethers(focus on the 7-9 brominated diphenyl ethers)..Accordingly we would discuss the effect of spiked concentrations and contents of TOCs on BDE-209 aging mechanism in soils by comparing the derived aging dynamic models,aging rate, equlibrum concentrations and equilibrium times, therefore assess the aging contribution to the decrease of BDE-209 in microbiological degradation process and ultimately give the basic background data about aging and adsorption by organic matters, which might help to further understand the microbial degradation process of BDE-209 in the soils. On the other hand, the dynamic concentration changes of lower brominated diphenyl ethers would give further reference on transform fate of BDE-209 in soil environment. .This study would provide valuable results to the scientific research on environmental behaviors of BDE-209.

十溴联苯醚(BDE-209)是使用量最大的一类溴代阻燃剂,其在环境介质中迁移/转化规律和生物有效性一直是有机污染物研究领域的热点问题。有研究表明受有机质吸附、老化作用的影响，BDE-209在土壤和沉积物中经微生物降解时质量平衡难以实现。本研究将有机质吸附作用从复杂的土壤环境中简化出来，以人工配制的模式土壤为研究对象，在配制不同有机质含量的模式土壤并表征其理化性质的基础上，较为系统地研究BDE-209在不同加标浓度、不同有机质含量的模式土壤中的老化规律，比较老化速度、平衡浓度、平衡时间等参数并拟合老化动力学模型，同时追踪老化过程中可能伴随的低溴代产物(重点关注7-9溴BDEs)的动态变化。从而评价老化对BDE-209微生物降解过程的贡献，最终为BDE-209在土壤中的微生物降解及生物有效性研究提供一套有机质吸附作用的"背景"参考数据。本研究将对BDE-209环境行为的研究提供有价值的科学参考

十溴联苯醚(BDE-209)是使用量最大的多溴联苯醚类阻燃剂,其在环境介质中迁移/转化规律和生物有效性一直是有机污染物研究领域的热点问题。鉴于机械式混合法配制的模式土壤在加标预实验中的结果不理想，本项目实施过程对研究内容作了必要的调整。采集无污染土壤做BDE-209的加标老化研究，加标浓度为1ppm，在含水率为20%的条件下于28℃密封保存棕色试剂瓶中老化培养120天，分别于0、1、5、10、2 0、30、60、90、120天取样分析了39种低溴BDEs和8种高溴代BDEs的含量。结果表明低溴代BDEs在整个培养期内无明显含量和组成的变化，以BDE-47和BDE-99的百分含量变化最明显，分别增加了6.38%和8.56%，BDE-183的百分含量有略微减少，比培养初期减少了3.31%。高溴代BDEs在培养120天后含量较培养初期有明显增加，同时BDE-209的含量在120天培养后有所降低。120天的老化培养时间尚不足以说明科学问题，研究仍需后续探索，需在有机质的结构表征、加标机体的选择和制备上做更深入的研究。