The degradation of erythromycin (ERY) and ethylparaben (EtP) in urban wastewater effluents at low concentration level during ozonation was investigated under different experimental conditions. Both substrates were rapidly eliminated within 2 min at low ozone dose of 0.3 mg L-1 and the experimental data were well fitted in the pseudo-first-order kinetic model. The ratio of HO center dot- and O-3-exposure (R-ct) at the inherent pH was found to be 1.9 x 10(-8). The degradation of ERY and EtP was pronounced at pH 8 compared to acidic pH conditions, while the degradation rate of both substrates was found to be matrix depended. It was also shown that both O-3(-) and HO center dot-mediated pathways are involved in the degradation of EtP, whereas the saturated-rich structure of ERY renders it O-3-recalcitrant. Under the optimum O-3 dose, the BrO3- concentration was found to be lower than 10 mu g L-1. Five and fifteen transformation products were elucidated during ERY and EtP oxidation, respectively. The root and shoot inhibition can be attributed to the oxidation products formed upon dissolved effluent organic matter transformation. Escherichia coil harbouring resistance to ERY survived ozonation better than EtP-resistant E. coil. However, neither ERY- nor EtP-resistant E. coli were detected after 15 min of ozonation. (C) 2016 Elsevier B.V. All rights reserved.