饮用水中卤代醌类新型消毒副产物的鉴定、形成转化与毒性效应研究

The newly discovered haloquinones (HBQs) formed in the drinking water disinfection processes are an important group of emerging disinfection byproducts (DBPs) because of their low concentration yet high toxicity. However, the formation and transformation mechanisms and health effects of haloquinone DBPs remain unclear due to the complexity of HBQs constituents and the difficulty in identification. This research will be proposed based on two key, yet unanswered, scientific questions:(1) How do characteristics of source water and technology of disinfection process affect the formation and transformation of haloquinone DBPs? (2) What are the toxicological effects and mechanisms of these haloquinone DBPS? To answer these questions, this research will select twelve possibly common haloquinones which contain 1, 2, 3, or 4 chlorine, bromine, and/or iodine atoms in the molecules as the target DBPs. We will improve existing and develop new analytical technologies, involving specific solid phase pre-concentration, effective HPLC separation, and sensitive MS/MS detection, for the purpose of HBQs identification. We will investigate the occurrence of haloquinones in Wuhan drinking water system. This is important because the formation of DBPs depends on the source water quality. To further study the formation and transformation mechanisms of haloquinones, we will choose two representative phenyl-containing amino acids, namely phenylalanine and tyrosine, to serve as candidate precursors. We will carry out lab-scale disinfection experiments and investigate the process of pipe transportation to study the formation of haloquinones and to investigate the key factors controlling the reactions. To determine the toxicity of haloquinones in vitro, we will use an array of cell lines originated from human bladder, lung, gastric, and liver tissues. We will further use the zebrafish in vivo model to investigate the oxidative stress and potential carcinogenic effects of haloquinone DBPs. The implementation of the proposed project will provide sound scientific basis for a better understanding of the occurrence, formation, and health risks of haloquinone DBPs.

饮用水消毒过程中产生的卤代醌类副产物因为高毒性而成为新的研究热点，但由于其成分复杂且难于鉴别，目前对其形成转化机制及毒性效应皆缺乏深入了解。本项目围绕两个关键科学问题立项:（1）不同源水及消毒工艺对卤代醌类新型消毒副产物生成转化的影响；（2）卤代醌类新型消毒副产物的致毒机理。选取典型的氯代、溴代及碘代苯醌为目标物质，建立高效灵敏的分离富集和分析鉴定方法，对卤代醌类消毒副产物在武汉市饮用水系统中的组成分布进行研究；以苯丙氨酸和对羟基苯丙氨酸作为前驱体，模拟消毒工艺并考察管网输送过程，研究卤代醌类消毒副产物的形成及转化过程；建立离体及活体毒理评价模型，利用重组细胞系对卤代醌类消毒副产物的毒性进行筛查并研究其致毒机理，同时选用具有促癌基因的斑马鱼作为活体模型来评估卤代醌类消毒副产物的氧化应激和潜在致癌效应。本项目的实施将为准确理解卤代醌类消毒副产物的形成转化机制，全面评估其健康风险提供科学依据。

饮用水消毒能有效杀灭源水中的病原微生物，氯化是消毒的最有效方法之一。在典型的饮用水处理和输送过程中，常用的消毒剂可能与其中存在的天然有机物或环境污染物发生多种化学反应，产生不同的消毒副产物（DBPs），尤其是其致突变性会导致罹患多种癌症的风险。消毒副产物种类繁多、结构多样并且浓度相对较低，当前只有大约30%被鉴别出来，因此迫切需要对饮用水中潜在的其它新型消毒副产物进行识别鉴定并对其毒性效应进行评估。卤代苯醌（HBQs）已被归类为毒性相对较高的卤化DBPs, 源水中溴碘的存在是高毒性溴代和碘代消毒副产物生成的重要因素，本项目研究了溴和碘的不同形态在长江中的赋存、水处理过程中的转化，为溴代及碘代苯醌类消毒副产物在长江沿岸自来水中的含量分布研究提供了基础；构建了挥发性及极性消毒副产物的非目标性筛选方法，为研究多种卤代苯醌类消毒副产物在水中的存在及转化提供了新的分析方法；建立了11种卤代醌类消毒副产物的分析方法，并据此对其在武汉市饮用水及输水管道中的含量分布进行了测定；对几种前驱体在次氯酸钠中的消毒过程进行模拟，发现卤代苯醌的生成量与前驱体的种类有关。在毒性效应评价方面，选取了几种新型消毒副产物HBQs为研究对象暴露斑马鱼胚胎，研究该类化合物对斑马鱼胚胎的胚胎毒性和氧化损伤效应，发现低浓度的卤代醌就对斑马鱼胚胎有显著的急性毒性效应和发育毒性，HBQs造成的氧化损伤为主要致毒机制，并且毒性效应与卤代醌的卤素取代位置和类型相关；同时利用HBQs暴露斑马鱼成鱼，结合转录组学的分析方法，研究了斑马鱼脑部和心脏对毒物胁迫的响应，结果表明，HBQs对成鱼也有较强的急性毒性，造成脑部组织和心脏组织病变的主要原因是氧化损伤，转录组学聚类分析提示，心血管发育和脑部神经递质相关通路受到显著影响。在去除卤代苯醌消毒副产物的材料合成方面，我们还制备了具有较高的孔隙率和丰富的微孔结构材料，其对水溶液中的典型HBQs表现出优异的去除性能。