Biological and photochemical degradation of cytostatic drugs under laboratory conditions

• Published in: Journal of hazardous materials Vol. 323; no. Pt A; pp. 319 - 328
• Main Authors: Franquet-Griell, Helena, Medina, Andrés, Sans, Carme, Lacorte, Silvia
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.02.2017
• Subjects: Advanced oxidation processes; Biodegradation; Cytostatic drugs; Kinetics; Photolysis; Biodegradation; Advanced oxidation processes; Kinetics; Photolysis; Cytostatic drugs
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2016.06.057

•Cytostatic drugs with reactive chemical groups are rapidly hydrolyzed.•Biodegradation is not capable to eliminate all cytostatic drugs.•UV-C and photolysis are not effective for the elimination of cytostatics.•UV-H2O2 eliminates all compounds and no traces are present after 4min.•Unless AOP is used, WWTP effluents are a main source of cytostatics to rivers. Cytostatic drugs, used in chemotherapy, have emerged as new environmental contaminants due to their recurrent presence in surface waters and genotoxic effects. Yet, their degradability and environmental fate is largely unknown. The aim of this study was to determine the degradation kinetics of 16 cytostatic drugs, prioritized according to their usage and occurrence in hospital and wastewater treatment plants (WWTP) effluents, through the following laboratory scale processes: hydrolysis, aerobic biodegradation, UV-C photolysis, UV-C/H2O2 and simulated solar radiation. Some drugs were unstable in milli-Q water (vincristine, vinblastine, daunorubicin, doxorubicin and irinotecan); others were photodegraded under UV-C light (melphalan and etoposide) but some others were found to be recalcitrant to biodegradation and/or UV-C, making necessary the use of advanced oxidation processes (AOPs) such as UV-C/H2O2 for complete elimination (cytarabine, ifosfamide and cyclophosphamide). Finally, radiation in a solar box was used to simulate the fate of cytostatic drugs in surface waters under natural radiation and complete removal was not observed for any drug. The degradation process was monitored using liquid chromatography coupled to high resolution mass spectrometry and pseudo-first order kinetic degradation constants were calculated. This study provides new data on the degradability of cytostatic compounds in water, thus contributing to the existing knowledge on their fate and risk in the environment.