Decomposition and complete degradation of two endocrine disrupters, namely 17 beta-estradiol (E-2) and bisphenol A (BPA) in aqueous medium by using ozone (O-3) only and O-3/UV advanced oxidation techniques (AOT) has been studied. The efficiency of the 03 systems used were determined based on the initial conversion and complete degradation of the substrates. Within the limits of the 03 dosages used, coupling of UV decreased the O-3 consumption by 22.5% in converting the same amount of E,. Also the time to convert the same amount of E2 was considerably decreased. It was observed that there is no significant difference in 03 amount consumed for complete conversion of BPA by O-3 and O-3/UV systems. However, when O-3 dosage decreased the amount of BPA conversion exhibits significant differences between two processes. The intermediate products formed during the oxidation of E2 were determined to be formed by oxidation of aromatic side of E2 with O-3/(OH)-O-center dot radical. (c) 2005 Elsevier B.V. All rights reserved.