受污水有机物影响的饮用水中新兴溴代含氮消毒副产物的生成机理及毒性研究

Due to high toxicity, brominated and nitrogenous disinfection byproducts (DBPs) formed in drinking water are of great concern. However, most of studies currently focus on commonly known DBPs, which belong to aliphatic compounds; studies on new brominated nitrogenous DBPs are very limited. The drinking water quality of downstream cities, which use rivers as drinking water sources, may be impacted by municipal wastewater discharged from upstream cities; the structures of wastewater organics are different from that of natural organic matter, more new brominated nitrogenous DBPs, which are not known yet, may be formed in downstream drinking water during chlorination. In this study, under simulated biodegradation condition and chlorination condition, by using precursor ion scan (m/z 79 or 81) method with electrospray ionization-triple quadrupole mass spectrometry, brominated DBPs formed from wastewater organics will be detected; different factors (e.g., wastewater organics, biodegradation condition, chlorination condition, and bromide concentration) for the formation of new brominated nitrogenous DBPs will be deeply investigated; then, the formation mechanism of those DBPs will be explored. Moreover, the toxicity of new brominated nitrogenous DBPs from wastewater organics will be evaluated using Chinese hamster ovary cells. Results from this study are beneficial to enhancing the knowledge about the chemical processes and hazards of wastewater organics during drinking water chlorination, and providing a theoretical base and technical guidance for the DBPs control.

饮用水中溴代和含氮消毒副产物（DBPs）因毒性高而备受关注。但是目前的研究多数是关于脂肪族类的常规DBPs，有关新兴溴代含氮DBPs的研究较少。而以河流中下游作为饮用水取水水源的城市水质会受到上游城市生活污水排放的影响；由于污水有机物与天然有机物结构不同，下游饮用水在氯消毒时可能生成更多未被关注的新兴溴代含氮DBPs。据此，本课题拟模拟污水有机物自然降解和氯消毒条件，采用电喷雾离子化三重四极杆质谱，通过前体离子扫描(质荷比79或81)方法检测污水有机物产生的溴代DBPs；深入分析不同因素（污水有机物种类、降解条件、氯消毒条件、溴离子浓度等）对新兴溴代含氮DBPs生成的影响，并探讨其生成机理；同时，通过中国仓鼠卵巢细胞评估污水有机物生成新兴溴代含氮DBPs的细胞毒性。本项目的研究结果有利于全面认识污水有机物在饮用水消毒工艺中的化学过程和危害性，为其产生的DBPs的控制提供理论依据和技术指导。

饮用水中溴代和含氮消毒副产物（DBPs）因毒性高而备受关注。而以河流中下游作为饮用水取水水源的城市水质会受到上游城市生活污水排放的影响；由于污水有机物与天然有机物结构不同，下游饮用水在氯消毒时可能生成更多新兴或未被关注的新兴溴代含氮DBPs。据此，本课题模拟了污水有机物自然降解和氯消毒条件，比较了污水中典型有机物（单宁酸、牛血清蛋白和葡萄糖等）经生物降解和转化后在氯消毒过程中生成DBPs的主要特征；其中重点研究了以单宁酸为前驱体的溴代DBPs随氯反应时间及单宁酸降解时间的变化规律，解析了若干类别已生成的新兴溴代DBPs的结构信息并据此探究了单宁酸生成主要类别消毒副产物的转化机理。同时探究了受污水影响的饮用水在氯消毒过程中生成新兴卤代DBPs的规律。然后利用中国仓鼠卵巢细胞评价水样中生成的单个新兴卤代DBP（包括溴代和含氮类DBPs）的比较细胞毒性，并建立了定量构效关系（QSAR）模型解释具有不同组成结构的DBPs表现出不同毒性大小顺序的原因。此外，对于无法获得标准品的新兴或新鉴定的DBPs, 通过在之前研究中利用沙蚕胚胎幼虫建立的发育毒性模型和藻类建立的生长抑制毒性模型来评估了其相对毒性大小。最后，研究了新兴芳香族卤代DBPs与人血清白蛋白（HSA）的相互作用，并考察该结合过程对HSA结构和功能的影响。以上研究所得结果能为更好控制饮用水中新兴DBPs的生成和更全面地认识消毒副产物对人体健康的影响及作用机制提供相应的依据。