Photocatalytic degradation of cyclophosphamide and ifosfamide: Effects of wastewater matrix, transformation products and in silico toxicity prediction.

Abstract

Antineoplastic drugs have been identified in surface water and effluents from wastewater treatment and, once in the environment, may be harmful to aquatic organisms, as these compounds are possibly mutagenic, genotoxic, cytotoxic, carcinogenic and teratogenic. This work investigated the photodegradation of cyclophosphamide (CP) and ifosfamide (IF) using ruthenium doped titanate nanowires (Ru-TNW) in distilled water (DW) and in wastewater (WW) from secondary wastewater treatment, under UV-Vis radiation. The results indicated that Ru-TNW showed photocatalytic activity for the two cytotoxic drugs with the half-life (t1/2) of 15.1\u202fmin for CP and 12.9\u202fmin for IF in WW. Four CP transformation products (TPs) and six IF TPs from the photodegradation process are here reported. These TPs were elucidated by high-resolution mass spectrometry. For both pollutants, the results showed different time profiles for the TPs when WW and DW were used as matrix. Overall, in the WW there was a higher production of TPs and two of them were detected only in this matrix. In other words, environmental matrices may produce different TPs. Degradation pathways were proposed and both drugs bear similarities. Additionally, in silico toxicity were performed by quantitative structure-activity relationship models. The predictions indicated that the TPs, with the exception of one IF TP, presented high mutagenic potential.