饮用水中含氮消毒副产物形成机制研究

Nitrogenous disinfection byproducts (N-DBPs) including haloacetonitriles (HANs), halonitromethanes (HNMs), haloacetamides (HAAms) and nitrosamine are an emerging class of disinfection by-products (DBPs) was found to be more cytotoxicity and genotoxicity. The main problem of current research is to determine N-DBPs in drinking water because these compounds with different polarity and solubility are generally present at sub-ng/L levels in drinking water. Some congeners of N-DBPs are very easy to volatile. The precursors of N-DBPs are not uniform that is possible from a variety of amino acid, amino sugars and organic nitrogenous organics. More toxic and unregulated N-DBPs were generated in advanced treatment process with complex pollutants in source water. This project will optimize preparation technique and state-of-the-art analytical instrument to determine the occurrence and concentration of all congeners of N-DBPs. Synthetic standard solution used to as source water in simulated experiment. Chloration, chloroamine, ultraviolet and ozone are used to disinfect authentic source water. Optimized solid-phase microextraction with gas chromatography–mass spectrometry (GC/MS) and solid phase extraction with ultra performance liquid chromatography (UPLC)/MS are applied to determine occurrence and concentration level of N-DBPs. Developed GC (GC×GC)-TOF/MS and UPLC-TOF/MS method are used to quality unregulated N-DBPs, precursor compounds and transformation products. In-vitro bioassay also are used to determine the toxic effects of N-DBPs in disinfected drinking water and to assess their genotoxic and cytotoxic. This project will discuss the effects on formation of N-DBPs under different source water using different disinfection techniques and obtain possible formation pathway and mechanism of N-DBPs using the water quality parameters (including total organic carbon, total organic nitrogen and total halide). Typical disinfection process (coagulation, sedimentation and filtration) are applied to obtain the influence factors of formatting and removing N-DBPs. We hope this research will provide possibilities for improving safe drinking water and develop effective disinfection methods and techniques.

含氮消毒副产物(N-DBPs)，主要包括卤乙腈、卤代硝基甲烷、卤代酰胺和亚硝胺等，是一类具有较强遗传毒性/突变毒性的新型饮用水消毒副产物。针对多类别的N-DBPs在水中浓度均较低（˂ng/L）、极性和水溶性差异较大及部分N-DBPs极易于挥发等特点，本研究拟构建和发展高通量的分析方法，系统调查在典型消毒方式下N-DBPs的存在现状和浓度水平。基于不同的水源水质和复杂的污染状况，利用配水实验模拟典型消毒过程，在筛查分析的基础上，发展时间飞行质谱（TOF-MS）方法定性分析N-DBPs的转化产物。基于化学分析和体外生物毒性测试数据，研究N-DBPs（溴或碘代N-DBPs）的生成、转化和衰减规律，探讨其形成机制和影响因素。比较在配水模拟典型消毒工艺过程中N-DBPs浓度的变化及生物毒性的增减，初步获得常规消毒工艺对N-DBPs生成和去除的影响，为提高饮用水的安全和开发有效的消毒工艺提供数据基础。

基于固相萃取（SPE）—超高效液相色谱串联质（UPLC-MS/MS）技术， 建立了同时测定环境水样中 135 种 PPCPs类化合物的分析方法。实验确定为采用Oasis WAX O 串联 Oasis HLB柱，碱性甲醇和酸性甲醇分别为洗脱溶剂，调节水样的 pH 值为 6-8时，能够使得PPCPs在饮用水基质中的回收率范围为 50 -150% 之间，分析方法的检出限范围为 0.004 -11 ng/L。对国内主要水源地和饮用水处理过程进行了含氮消毒副产物和前体化合物的调查。结果显示，共有70 种药物被检出，频率最高的化合物包括磺胺类、大环内酯、镇痫剂、消炎药及β-阻断剂等。检出浓度较高的化合物有林可霉素、磺胺甲恶唑对乙酰氨基酚和1,7 -二甲基黄嘌呤等，检出最高浓度可达 134 ng/L。卡马西平和避蚊胺在所有样点中都有检出，浓度范围分别为 0.8 -10.2 ng/L 10.2 ng/L和 0.01 -3.5 ng/L 3.5 ng/L。含氮PPCPs在中国地表水中是普遍存在的，其检出浓度典型为ng/L级，最主要的检出类别为抗生素类含氮PPCPs，其中又以磺胺类和喹诺酮类PPCPs为最主要的检出类别，应给予更多的关注。东江流域是本次调查中检出目标化合物种数最多且平均检出总浓度最高的流域，东江流域地表水中含氮PPCPs的污染问题应当引起相关部门的重视。以用水处理工艺过程中的多类别药物变化规律进行了研究。以连云港市自来水厂为例，常规处理工艺对絮凝、沉淀对药物和农转化产等新型污染物无明显的去除效果，氯消毒对部分化合物有去除效果但这些微量污染物的去除起主要作用处理工艺为臭氧和生活性炭工艺。