Combining Analytical Strategies to Provide Qualitative and Quantitative Analysis and Risk Assessment on Pharmaceuticals and Metabolites in Hospital Wastewaters

The improper disposal of hospital wastewater (HWW) is a primary source of pharmaceutical pollution in aquatic systems. The complexity of the HWW matrix presents significant challenges for analytical chemists, necessitating meticulous sample preparation as the initial step for the analysis, followed by instrumental analysis. In the present study, a combination of dispersive solid phase extraction and solid phase extraction was evaluated for the preparation of HWW samples from two hospitals in Porto Alegre, Brazil, both for screening and quantitative analysis. The experiments performed by UHPLC-QTOF MS allowed the identification of 27 compounds and 23 suspected compounds. Furthermore, the UHPLC-QqQ-MS analysis enabled the quantification of 21 compounds, with concentrations ranging from 1.17 µg L−1 to 213.33 µg L−1. Notably, the pharmaceutical ciprofloxacin was detected at a concentration that exceeded the reported risk level for Microcystis aeruginosa. The environmental risk assessment revealed that the risk quotient (RQ) for several of the compounds quantified in the two HWW matrices exceeded 1, with the risk quotient of the mixture of compounds (RQmix) being approximately 30 × 106 for Hospital A and 20 × 106 for Hospital B. According to these findings, the two HWW systems exhibited risk levels for aquatic species and small rodents, thereby contributing to the persistence of pharmaceuticals in the environment.