Occurrence and human risk assessment of pharmaceutically active compounds (PhACs) in indoor dust from homes, schools and offices.

This study investigates the current situation and possible health risks due to pharmaceutically active compounds (PhACs) including analgesics, antibiotics, antifungals, anti-inflammatories, psychiatric and cardiovascular drugs, and metabolites, in indoor environments. To achieve this objective, a total of 85 dust samples were collected in 2022 from three different Spanish indoor environments: homes, classrooms, and offices. The analytical method was validated meeting SANTE/2020/12830 and SANTE/12682/2019 performance criteria. All indoor dust samples except one presented at least one PhAC. Although concentration levels ranged from < LOQ to 18 µg/g, only acetaminophen, thiabendazole, clotrimazole, and anhydroerythromycin showed quantification frequencies (Qf %) above 19% with median concentrations of 166 ng/g, 74 ng/g, 25 ng/g and 14 ng/g, respectively. The PhAC distribution between dust deposited on the floor and settled on elevated (> 0.5 m) surfaces was assessed but no significant differences (p > 0.05, Mann-Whitney U-test) were found. However, concentrations quantified at the three types of locations showed significant differences (p < 0.05, Kruskal-Wallis H-test). Homes turned out to be the indoor environment with higher pharmaceutical concentrations, especially acetaminophen (678 ng/g, median). The use of these medicines and their subsequent removal from the body were identified as the main PhAC sources in indoor dust. Relationships between occupant habits, building characteristics, and/or medicine consumption and PhAC concentrations were studied. Finally, on account of concentration differences, estimated daily intakes (EDIs) for inhalation, ingestion and dermal adsorption exposure pathways were calculated for toddlers, adolescents and adults in homes, classrooms and offices separately. Results proved that dust ingestion is the main route of exposure, contributing more than 99% in all indoor environments. Moreover, PhAC intakes for all studied groups, at occupational locations (classrooms and offices) are much lower than that obtained for homes, where hazard indexes (HIs) obtained for acetaminophen (7%-12%) and clotrimazole (4%-7%) at the worst scenario (P95) highlight the need for continuous monitoring.