溶解态黑碳（氮）在水源水中的分布特征及生成氯化消毒副产物的研究

Dissolved black carbon and dissolved black nitrogen are the important constituents of dissolved organic matters (DOM) in water environment. The proposed project will study the levels and sources of dissolved black carbon and dissolved black nitrogen in raw water, the formation and toxicity of disinfection by-products (DBPs) of dissolved black carbon and dissolved black nitrogen because these problems have not known. The project includes (1) Investigating the levels and seasonal variations of dissolved black carbon and dissolved black nitrogen in different types of raw water through molecular tracer technique and X-ray photoelectron spectroscopy; (2) Exploring the sources of dissolved black carbon in raw water by stable carbon isotopic analysis; (3) Preparing the samples of dissolved black carbon and dissolved black nitrogen from different biomass, analyzing their elemental compositions and characterizing their structures; (4) Studying the formation and genotoxicity of DBPs and Identifying unknown DBPs through simulated chlorination/chloramination of biomass-derived dissolved black carbon and dissolved black nitrogen; (5) Revealing the contribution and influence of dissolved black carbon and dissolved black nitrogen on DBPs formation of DOM in drinking water by comparing with the DBP formation of DOM from the representative raw water; (6) Elucidating the formation mechanism of DBPs by chlorination/chloramination of model compounds with similar structures of dissolved black carbon and dissolved black nitrogen, respectively based on the above characterization of their structures. The results of this project will provide the theoretic basis for source and seasonal variations of dissolved black carbon and dissolved black nitrogen in raw water, their transformation and fate in the disinfection of drinking water.

溶解态黑碳（氮）是水环境中溶解性有机质的重要组成。本项目针对水源水中溶解态黑碳（氮）含量和来源不清，其在饮用水处理中生成消毒副产物（DBPs）及其危害也尚不清楚等科学问题开展研究。拟采用分子标志物、X射线光电子能谱方法测定不同类型水源水中溶解态黑碳（氮）的含量，分析其季节性变化规律，采用稳定碳同位素分析法探究其来源；制备不同生物质碳源溶解态黑碳（氮），测定元素组成及结构特征；模拟溶解态黑碳（氮）的氯化和氯胺化，研究DBPs的生成和毒性变化规律，甄别未知DBPs；对比溶解性有机质生成DBPs揭示水中溶解态黑碳（氮）对饮用水DBPs生成的贡献；依据本项目溶解态黑碳（氮）结构表征结果选择模型化合物，通过其氯化和氯胺化DBPs的分析，阐明溶解态黑碳（氮）生成DBPs的机制及其影响因素。研究结果对揭示水源水中溶解态黑碳（氮）的来源、季节性变化规律以及在饮用水系统中的转化归趋具有重要的理论意义。

水中溶解性黑碳/氮（DBC/DBN）是溶解性有机质的重要组成。本研究优化苯多羧酸法测定水样中DBC的方法，采集不同水期长江中下游河流、湖泊、运河、水库等饮用水源水样，监测DBC的浓度水平，分析了DBC与水质参数的相关性，采用X射线光电子能谱（XPS）表征了DBN的特征，用元素分析-稳定同位素质谱方法推测了水源水中DBC的来源。结果表明，水源水中DBC含量在60-270μg/L，DBN含量在0-147μg/L。DBC含量：水库水>运河水>湖水>河水，且丰水期>枯水期。DBC含量与水样的UV254和COD存在显著正相关关系，水源水中的DBC主要来源于生物质燃烧。.在对水源水DBC/DBN浓度水平和分布特征调查的基础上，在实验室制备了六种不同生物质来源的DBC，对其元素组成和结构进行了表征。并通过模拟饮用水絮凝和氯化处理，分析生成的氯化消毒副产物（DBPs），并利用中国仓鼠卵巢细胞（CHO）探究了DBPs的细胞毒性。结果表明，生物质源DBC芳香性很高，且含有较多的含氧基团。在模拟絮凝过程中，能去除20%的DBC，DBC能与次氯酸钠作用生成DBPs，主要为卤乙酸和三卤甲烷。不同生物质源DBC模拟氯化72小时后生成DBPs具有不同的细胞毒性，毒性由强到弱为水稻壳>玉米秸秆>小麦秸秆>竹子>水稻秸秆>玉米芯。.测定不同水源水DOM模拟氯化后的细胞毒性，并与DBC氯化后的细胞毒性进行对比，计算水源水中DBC对生成DBPs的毒性贡献。结果表明，水源水中DBC虽然仅占DOM的1-2%，生成DBPs的毒性贡献却达到3%-12%，考虑到DBC在水源水中的广泛分布，其在饮用水处理过程中的风险需要更多的关注。.选择含羟基和羧基多环芳烃（蒽酚、蒽酸、芘酚、芘酸等）作为DBC的模型化合物，利用高分辨质谱对模型化合物模拟氯化后的产物进行了分析，推测反应路径。研究发现，模型化合物和DBC在模拟氯化后均能生成卤代苯醌、苯多羧酸等产物，再进一步反应生成小分子DBPs。