Multivariate Optimization of Analytical Methodology and a First Attempt to an Environmental Risk Assessment of β-Blockers in Hospital Wastewater

This preliminary study evaluated an assessment of the risks arising from environmental exposure to β-blockers from wastewater of an university hospital (University Hospital of Santa Maria (HUSM), Rio Grande do Sul State, Brazil). Propranolol showed the highest risk quotient (0.56). The occurrence of β-blockers was evaluated using an analytical procedure SPE‑HPLC-FLD (solid phase extraction-high performance liquid chromatography with fluorescence detection), optimizing the variables sample pH, water pH, and methanol:acetonitrile:formic acid ratio of the elution stage. The average concentrations of atenolol, metoprolol and propranolol for a sampling period of one week were 2.45 ± 1.14, 4.67 ± 1.63 and 0.70 ± 0.88 μg L–1 in the ‘Emergence’ sewage; 0.95 ± 0.68, 0.70 ± 0.33 and 0.315 ± 0.62 μg L–1 in the ‘HUSM general’ sewage and 1.26 ± 0.47, 1.27 ± 0.35 and 0.56 ± 0.47 μg L–1 in the ‘Receiving waters’, the receptor stream of the effluents, respectively. Propranolol showed an MEC/PNEC ratio > 1, and thus requires more attention in terms of toxicity. The occurrence of β-blockers and the associated environmental risks demonstrate the need of a more efficient treatment system for the hospital wastewater.