多氟烷基磷酸酯（PAPs）在水生生物体中的富集与转化机制研究

Polyfluorinated alkyl phosphates (PAPs) are being produced and used as substitutes of N-Ethyl perfluorooctanesulfonamido ethanol-based phosphate esters, which have been regulated in US and other countries. They are widely applied in food paper package, personal care products, pesticide formula and so on. They can release from the products and were detected at high level in some environmental matrices. Previous investigations demonstrated that PAPs could be biotransformed by microorganisms and in rats to a series of intermediate products and perfluorocarboxlates (PFCAs) with different carbon chain length, which are more toxic than PAPs. However, little is known about the bioaccumulation and transformation of PAPs in aquatic organisms. The target compounds in this study are PAPs with different carbon chain length and substitution degrees. The objectives are to investigate the contamination levels and characteristics of PAPs in typical watersheds, and the bioaccumulation of PAPs in different aquatic organisms in field. Based on this, we will study the bioaccumulation, elimination and degradation of PAPs in various of tissues of the organisms using both in vivo and in vitro experiments. The biotransformation products are identified and quantified in the organism tissues. Thereafter, we try to delineate the transformation pathways and mechanisms, and illustrate the sites where the transformation takes place. Based on the research results, quantitative assessment of manufacturing sources would be made to the studied watersheds. The research results of this project will lay theoretical basis for the contribution of PAPs to the load of PFCAs and profiles in the environment. They also provide scientific evidences for management and risk assessment of PAPs in the environment.

多氟烷基磷酸酯（PAPs）作为被限制使用的N-乙基全氟辛基磺酰醇磷酸酯的替代品正被大量生产和使用，在某些环境介质中具有较高的污染水平。已有研究表明PAPs可被转化为毒性更强的中间产物和全氟羧酸（PFCAs），是环境中这些有毒物质的重要来源。但是，关于PAPs在水生生物体内富集转化的研究极少。本项目拟以不同碳链长度和取代程度的PAPs为研究对象，通过野外调查了解我国典型地区水体中PAPs的污染特征、生物富集和归趋。在此基础上，通过活体和离体模拟实验相结合的方式，系统研究PAPs在典型水生生物体中的富集、代谢、转化过程，鉴定代谢产物并分析其消长规律，阐明生物体内代谢动力学及降解发生的关键器官，厘清代谢降解路径，揭示代谢发生的主要机制和关键控制因素，为准确评价PAPs对环境中PFCAs的贡献和正确评估PAPs在环境中的生态风险以及为环境管理部门制定科学的管理规范提供理论依据。

（1）通过野外调查和实验室工作，研究了多氟烷基磷酸酯（PAPs）在我国典型水体和生物体中的污染水平和特征，发现6:2多氟烷基磷酸二酯（6:2 diPAPs）在太湖水相和沉积物中的检出率为100%，diPAPs的沉积物-水分配系数log KOC和log BAF均低于根据log KOW预估的值。（2）通过体内暴露实验和体外孵育实验，研究6:2 diPAP和8:2 diPAP在水生生物体内的富集、代谢和转化，发现肝脏是发生生物浓缩和生物转化的鱼类的主要组织，一些酶如酸性磷酸酶（ACP）和谷胱甘肽S-转移酶（GST）可能会参与相I和相II的转化反应。8:2 diPAP比6:2 diPAP更容易转化为相I产物，生成更多量的氟代不饱和羧酸（FTUCAs）和氟代饱和羧酸（FTCAs），暴露于长链diPAPs的水生生物可能会遇到比预期更高的风险。（3）通过研究8:2 diPAP在三种典型底栖生物中的生物积累和生物转化，发现生物积累和生物转化行为与物种相关。水丝蚓对8:2 diPAP生物累积能力大于泥鳅和锦鲤, 水丝蚓可作为8:2 diPAP污染沉积物的合适的生物指示物种。泥鳅具有最强的转化8:2 diPAP能力。（4）6:2和8:2 diPAPs具有内分泌干扰活性，也表现出甲状腺干扰能力，可能会对生殖和甲状腺内分泌系统造成永久性损伤。6:2和8:2 diPAPs可能并不是长链PFASs的合适的替代品。