Formation of Stable Transformation Products of Pharmaceuticals in the Water Treatment Cycle

After human consumption, pharmaceutically active substances can be excreted and enter the effluent treatment facilities. Often degradation in sewage and water treatment and the environment is incomplete, resulting in the formation of transformation products. Within the Pharmas project (EU grant agreement no. 265346) three anticancer drugs were evaluated for the formation of stable transformation products. The compounds selected are 5-Fluorouracil (5-FU), Imatinib (IB) and Cyclophosphamide (CPA). Treatment processes include the most commonly used ones i.e. chlorination, and ozonation for drinking water, photolysis with UV radiation for sewage treatment. To assess the behavior in the environment, photolysis with a Xenon lamp and readily biodegradability was tested additionally. The study found that 5-FU was degraded by chlorination, ozonation and UV lamp treatment. No TPs were identified although presence is likely after ozonation and UV. IB was degraded by chlorination, ozonation, Xenon and UV lamp treatment. One TP was isolated after chlorination. CPA was partly degraded by ozonation, and the results are inconclusive regarding biodegradation. Two TPs were isolated after ozonation and biodegradation. CPA wasn’t degraded fully by any treatment.