Anticancer Drug Docetaxel in Hospital Effluent: Development of Chromatographic Method, Occurrence, and Degradation via Ozonation

Anticancer agents, specifically designed to induce cell death in neoplastic cells, have become increasingly prevalent contaminants in various environmental matrices. Their extensive use has resulted in their detection across multiple settings, including hospital and pharmaceutical factory effluents, domestic wastewater, and surface waters. This study aimed to develop an analytical method for determining docetaxel residues in hospital effluent using Solid-Phase Extraction (SPE) and HPLC-DAD. The SPE method demonstrated R² greater than 0.99, with recovery rates reaching 95% and an RSD of less than 2%. The LOQ was established at 10.0 μg L−1, with no significant matrix effects observed for docetaxel. The validated SPE method was deemed suitable for its intended application, as all evaluated parameters met the specifications outlined in current regulatory guidelines. Docetaxel was quantified at 29.9 μg L−1 (±1.3%) in one of the 14 effluent samples collected over a week from the Federal University of Santa Maria Hospital (HUSM). Given that the microbiological treatment system at HUSM does not effectively remove this drug, an advanced degradation process using ozonation was investigated. A Dispersive Liquid-Liquid Microextraction (DLLME) method was developed for bench-scale degradation studies and subsequently applied to assess the degradation of docetaxel via ozonation in real samples. The optimized extraction conditions for docetaxel involved a 10 mL hospital effluent sample at pH 9, with ionic strength adjusted using Na₂SO₄. Methanol served as the disperser solvent, while chloroform was the extracting solvent. The ozonation process achieved a removal efficiency exceeding 97% after 60 minutes of reaction, under optimal conditions of pH 7 and an average ozone production rate of 1.5 g O₃ h⁻¹. These findings indicate that ozonation is an effective treatment strategy, significantly reducing docetaxel concentrations in hospital effluent within a short reaction timeframe.