洞庭湖沉积物中典型甲状腺激素干扰物的效应评价与因果关系鉴定

Large number of technical sodium pentachlorophenate have been sprayed around typical regions of schistosomiasis prevalence in Lake Dongting to kill Oncomelania hupensis Gredler. Many organic byproducts and degradation products will be carried into local aquatic environment.These pollutants may induce thyroid hormones (THs) disrupting effects in wildlife. Previous studies focus on pentachlorophenol and dioxins distribution in the Lake. However study on assessment the combined effect thyroid hormone-disrupting chemicals is quite scant.It is difficult to identify thyroid disrupting chemicals (TDCs) and primary contributors in sediment in the absence of effective method. Zebrafish (Danio rerio)larvae as a toxicity testing model were developed, RT-PCR was used to assay the gene expression on larvae exposed by sediments extract, the two-hybrid thyroid hormone receptor (TR) yeast assay was also used to quantify agonistic and antagonistic TR activities of these TDCs in sediments. The combined disrupting effect caused by TDCs were studied by both in vivo and in vitro bioassays. Column chromatographys were applied to separate and purify typical fractions, each of these fractions eluted with different solvents from column chromatographys were bioassayed by the two-hybrid TR yeast, these fraction will be analyzed by instruments which the disrupting effect were detected in; the correlations between effect and TDCs levels were explored by statistical method; the primary contributors will be identified. The item will develop a method for assessment the combined thyroid disrupting effect and identification of chemicals responsible for it in sediment from typical regions of schistosomiasis prevalence. The results will be beneficial to control and minify these objective TDCs in the study regions, and to develop China guidance method of assessment the combined thyroid disrupting effect and identification of chemicals responsible for it.

洞庭湖区是我国最大的湖沼型血吸虫病疫区，因长期使用五氯酚钠灭螺，可能导致五氯酚钠生产过程中的副产物和施用后的降解产物大量积累在湖区沉积物中。目前仅有少量关于五氯酚和二噁英在湖区的分布特征研究，有关湖区复合污染导致的甲状腺激素（THs）干扰效应研究还相当欠缺。本申请拟建立重组THs受体基因酵母技术和斑马鱼幼鱼相关基因表达的RT-PCR检测技术，评价复合污染的THs干扰效应；通过优化多种填充柱分离纯化技术和仪器分析技术，鉴定沉积物有机萃取物中甲状腺激素干扰物(TDCs)的类别；并探索干扰效应和污染物之间的定量关系；归纳出一套沉积物中TDCs干扰效应评价与因果关系鉴定的方法。为我国TDCs毒性鉴定和效应评价体系规范的建立与完善提供前沿性的研究基础，为湖区典型TDCs的控制与消减提供重要的参考数据，具有重要的理论创新和现实意义。

洞庭湖区是我国最大的湖沼型血吸虫病疫区，因长期使用五氯酚钠灭螺，导致五氯酚钠生产过程中的副产物和施用后的降解产物大量积累在湖区沉积物中。课题研究了典型甲状腺激素干扰物（TDCs）的毒性鉴定和效应评价方法，建立了重组甲状腺激素受体基因酵母技术和斑马鱼幼鱼相关基因表达的RT-PCR检测技术，评价了沉积物萃取物中多种TDCs复合暴露的甲状腺激素干扰效应；建立了沉积物中PCDD/Fs, CBs, PCBs, CPs和PCA等五类TDCs的定性定量分析方法，鉴定了沉积物萃取物中PCDD/Fs, CBs, PCBs, CPs和PCA的污染特征与强度；以湖区优势污染物PCP为代表性TDCs研究了暴露浓度与甲状腺激素干扰效应的关系，结果表明环境浓度PCP的长期低剂量暴露会干扰斑马鱼血浆中的甲状腺激素水平，以及与甲状腺激素代谢和下丘脑-脑垂体-甲状腺(H-P-T)轴信号通路相关的基因表达。研究成果为湖区典型TDCs的控制与消减提供了重要的参考数据，具有重要的现实意义。