Photocatalytic degradation of chlothianidin: effect of humic acids, nitrates and oxygen
T16N1
M.B. Kralj, E.G. Dilcan, G. Salihoğlu, D.M. Mazur, A.T. Lebedev, P. Trebše
The use of neonicotinoid insecticides has been constantly revised due to their impact on bees causing their decrease and bee malady. Unfortunately, because of the worldwide differences in pesticide regulation, chlothianidin is still allowed in European Union for greenhouse use and worldwide in some cases without any restictions. Lately, it was detected, on soil particles, in raw and drinking waters. The preparation of drinking waters implies different purification processes, including chlorination, ozonation, UV irradiation and nowadays advanced oxidation processes including TiO2. The TiO2 photocatalytic degradation of chlothianidin in the presence of oxygen, nitrate and humic acids was followed by kinetic studies, whereas the photoproducts formed were identified using liquid chromatography/tandem mass spectrometry. The efficiency of different set-ups of photocatalytic degradation of chlothianidin was evaluated by identification of photoproducts and bioluminescence inhibition of bacteria Vibrio fischeri. The results indicated that the less harmful photoproducts are generated in the samples with added humic acids.