The overall assessment of simultaneous photocatalytic degradation of Cimetidine and Amisulpride by using chemical and genotoxicological approaches

Pharmaceutical Active Compounds (PhACs) are of particular interest among the emerging contaminants detected in the aquatic environment. Commonly, PhACs exist as complex mixtures in aquatic systems, causing potential adverse effects to the environment and human health than those of individual compounds. Based on the increasing interest in the contamination of water resources by PhACs, the photocatalytic degradation of Cimetidine and Amisulpride as a mixture in combination with their toxic and genotoxic effects before and after the treatment were evaluated for the first time. The toxic, genotoxic and cytotoxic effects were investigated using the Trypan Blue Exclusion Test and the Cytokinesis Block MicroNucleus (CBMN) assay in cultured human lymphocytes. The photocatalytic degradation of the PhACs was studied in ultrapure water and environmentally relevant matrices using UV-A and visible (Vis) irradiation and C-TiO₂ (TiO₂ Kronos vlp 7000) as photocatalyst. High removal percentages were observed for both compounds under UV-A and Vis irradiation in ultrapure water. In lake and drinking water a slower degradation rate was shown that could be attributed to the complex composition of these matrices. Scavenging experiments highlighted the significant role of h⁺ and O₂^●- in the degradation mechanisms under both irradiation sources. Oxidation, dealkylation and deamination were the main degradation pathways. Regarding the individual compounds, Amisulpride was found to be more cytotoxic than Cimetidine. No significant differences of the genotoxic effects during the treatment were observed. However, a slight increase in cytotoxicity was observed at the first stages of the process. At the end of the process under both UV-A and Vis light, non-significant cytotoxic/toxic effects were observed. Based on the results, heterogeneous photocatalysis can be considered as an effective process for the treatment of complex mixtures without the formation of harmful transformation products.