广东省典型城市污泥中三氯生及其转化产物的分布特征

摘要

三氯生(triclosan,TCS)因具有良好的杀菌、抗菌特性而被广泛应用于个人护理用品中,已成为全球性的新型环境污染物.该研究建立了结合态TCS的定量表征方法,完善了不同赋存形态TCS的分析方法.在此基础上采用液相色谱-三重四级杆串联质谱和气相色谱-三重四级杆串联质谱,定量分析广东省7家污水处理厂污泥中TCS和甲氧基三氯生(methyl triclosan,MTCS)的含量水平和组成特征;并通过表征结合态TCS在城市污泥中的含量水平,初步探讨了TCS在污泥中的赋存状态和转化.结果显示,城市污泥中普遍存在TCS和MTCS,同时可检测到结合态TCS,其含量水平范围分别为374.4~27978.1、26.2~150.3和nd~129.1 ng?g-1,不同污水处理厂污泥中TCS或MTCS的含量可能受污水来源、日处理污水量、处理工艺等因素影响而存在明显差异;同时,污泥有机质可影响TCS的赋存形态.通过对不同污水源污泥中MTCS/TCS(0.3%~27.6%)和结合态-TCS/自由态-TCS(0.0%~8.6%)进行对比分析发现,生活污水源污泥中MTCS较多,结合态TCS较少,而混合污水源(即生活污水+工业废水)污泥则相反,表明TCS转化生成MTCS与TCS形成结合态之间可能存在竞争关系.研究结果可为加深对TCS环境转化与归宿的认识以及生态风险评估提供理论支撑.%Triclosan (TCS) is widely used in personal care products due to its powerful bactericidal and antibacterial properties, and it has become a global emerging contaminant. In this study, we developed the method for determination of bound residues of TCS, and improved the integrated analysis on environmental occurrence of TCS. Based on the developed method, TCS and methyl triclosan (MTCS) in sludge samples from seven wastewater treatment plants in Guangdong Province were determined by liquid chromatography-tandem mass spectrometry and gas chromatography-tandem mass spectrometry, respectively. Concentration levels of TCS and MTCS, the characteristics of bond residues of TCS in sludge were then discussed. The results indicated that TCS, MTCS and bound-TCS could detected in sludge, and the concentrations ranged from 374.4 to 27978.1 ng?g-1, from 26.2 to 150.3 ng?g-1, and from not detected to 129.1 ng?g-1 on dry weight, respectively. There were significant differences in the levels of TCS and MTCS in different sludge samples, which may be subject to wastewater sources, daily capacity and treatment technology etc. Simultaneously, organic matter could affected the forms of TCS in sludge. The results of MTCS/TCS (0.3%~27.6%) and bound-TCS/free-TCS (0.0%~8.6%) in sludge samples indicated that concentrations of MTCS were higher than that of bound-TCS in the sludge of domestic sewage source, whereas the reversed results were found in the sludge of mixed sewage source. It implied that a competitive mechanism was occurred between methylation and formation of bound residues of TCS. The results of this study can provide support for the understanding of environmental transformation, fate and ecological risk assessment of TCS.