大环内酯类抗生素在饮用水处理过程中的污染特征及其氯化反应机制

Pollution Characteristics of Macrolide Antibiotics During Drinking Water Treatment and Their Chlorination Reaction Mechanism

饮用水处理过程中抗生素的污染问题引起了人们的广泛关注.监测了6种大环内酯类抗生素(脱水红霉素、克拉霉素、竹桃霉素、罗红霉素、柱晶白霉素和泰乐菌素)在2座饮用水处理厂中的污染情况,并考察了典型大环内酯类抗生素泰乐菌素在氯化消毒处理过程中的反应特性.结果表明,6种大环内酯类抗生素均能在饮用水处理过程中检出,但是其浓度普遍较低,进出水中的浓度范围分别为0.18~3.97 ng·L^(-1)和0.02~1.91 ng·L^(-1). 6种大环内酯类抗生素在饮用水处理过程中的去除率相差较大,在18%(竹桃霉素)~100%(脱水红霉素)范围内.6种大环内酯类抗生素在氯化处理过程中降解缓慢,且受水质影响较大.其中,泰乐菌素的氯化降解遵循二级反应动力学模式,测得pH 7.0条件下二级反应动力学速率常数为0.77 L·(mol·s)^(-1).监测到的9种泰乐菌素氯化降解产物,反应途径主要包括叔胺羟基化、芳族氧化和内酯环环氧化加成等.

Antibiotic contamination in drinking water has attracted widespread attention.The pollution condition of six macrolide antibiotics(erythromycin⁃H2O,clarithromycin,oleandomycin,roxithromycin,leucomycin,and tylosin)in two drinking water treatment plants was monitored,and the reaction mechanism of tylosin,a typical macrolide antibiotic,during chlorination disinfection treatment was investigated.The results showed that the six macrolide antibiotics can be widely detected in the drinking water treatment processes;however,their concentrations were generally very low.The concentrations of macrolide antibiotics in the influents and effluents ranged from 0.18 ng·L^(-1) to 3.97 ng·L^(-1) and 0.02 ng·L^(-1) to 1.91 ng·L^(-1),respectively.The removal rates of the six macrolides in the drinking water treatment were different,ranging from 18%(oleandomycin)to 100%(erythromycin⁃H2O).The degradation of the six macrolides during chlorination was slow and greatly affected by water quality parameters.The chlorination degradation of tylosin followed the second⁃order reaction kinetic mode,with the kinetic rate constant of 0.77 L·(mol·s)^(-1) at pH 7.0.Nine chlorination degradation products of tylosin were detected,and the reaction pathways primarily included tertiary amine hydroxylation,aromatic oxidation,and epoxy addition.