The oxidation of two industrial chemicals abundant in the environment, i.e., benzothiazole (BTH) and 1H-benzotriazole (BTA) was investigated in UV and UV/H2O2-systems using polychromatic mercury lamp. Experiments were performed in Milli-Q (TM) water solutions of BTH and BTA at pH 5, 7 and 9 and in synthetic wastewater spiked with BTH and BTA pre-treated in membrane bioreactors (MBRs). Results showed that polychromatic UV-radiation is an efficient oxidative agent for BTH and BTA abatement in water and wastewater. In the kinetic study direct photolysis quantum yields at pH 7 were calculated as 0.022 and 0.051 for BTH and BTA, respectively, and the second-order rate constant for the reaction between investigated compounds and hydroxyl radicals ((OH)-O-center dot) were determined to be (9.5 +/- 1.7).10(8) M-1 s(-1) and (2.7 +/- 0.1).10(9) M-1 s(-1), for BTH and BTA at pH 7, respectively. Identification of transformation products performed with liquid chromatography coupled with high resolution tandem mass spectrometry provided information about 6 and 5 transformation products formed during the photodegradation of BTH and BTA, respectively. The Microtox bioassay showed that direct photolysis is efficient to detoxify BTH and BTA in aqueous solutions. (C) 2016 Elsevier B.V. All rights reserved.