Transformation of atrazine, carbamazepine, diclofenac and sulfamethoxazole by low and medium pressure UV and UV/H2O2 treatment

► LP and MP UV lamps were compared on product formation during UV(/H2O2) treatment. ► There was little difference in formed transformation products with the four tested OMPs in DI water. ► QToF-MS was used to screen for oxidation products and get transformation pathways. ► Transformation pathways were sequential for diclofenac and sulfamethoxazole. ► Transformation pathways were non-sequential for atrazine and carbamazepine.