In this study, the combined toxicity of UV/chlorinated products on Escherichia coli (E. coli) was investigated when ibuprofen (IBP) and tyrosine (Tyr) were used as two precursors. The median-effect equation and combined index (CI)-isobologram equation were used to evaluate the combined toxicity of UV/chlorinated products. Results revealed that the UV/chlorinated products originated from binary Tyr and IBP showed a synergism in toxicity on Escherichia coli at low concentration level while it turned into a clear antagonism effect above a f_a value of 0.2 in the toxicity trial. The combined toxic effects on E. coli were determined by both the potential toxicity mode of specific disinfection byproducts (DBPs) and the complicated interaction caused by Tyr and IBP. The addition of IBP decreased the yield of N-DBPs generated from Tyr, which dominated the effect of combined toxicity. Even though the antagonism predominated in toxicity effect on E. coli, the synergistic toxicity at low dose levels should be getting attention, which was more close to the natural concentration of N-DBPs in waters.

在这项研究中，当将布洛芬（IBP）和酪氨酸（Tyr）用作两种前体时，研究了UV /氯化产物对大肠杆菌（E. coli）的综合毒性。使用中值效应方程式和组合指数（CI）-等效线图方程式来评估UV /氯化产物的组合毒性。结果表明，UV /氯化产品来源于二元Tyr和IBP显示对在毒性的协同作用的大肠杆菌在低浓度水平，而它变成上述AF明确拮抗作用_一在毒性试验的0.2值。对大肠杆菌的综合毒性作用通过特定消毒副产物（DBP）的潜在毒性模式以及Tyr和IBP引起的复杂相互作用来确定。IBP的添加降低了从Tyr产生的N -DBPs的产量，其主导了组合毒性的作用。尽管拮抗作用主要是对大肠杆菌的毒性作用，但低剂量水平的协同毒性仍应引起注意，这与水中N -DBPs的自然浓度更为接近。