107 Assessment of in Vitro Toxicity of Inhalable Incidental Nanoparticles Originating in the Ceramic Industry

Abstract

Abstract Assessing exposure to nanomaterials in industrial workplaces is a widespread challenge. Nanoparticle release was evaluated, under real-world operating conditions, in one thermal spraying and one tile firing facility. Nanoparticles were characterised in terms of mass and number concentrations (µg/m3; /cm3), particle size distribution, chemical composition and morphology, and in vitro toxicity. The present work targets especially the toxicological characterisation of the aerosols sampled. Particles <2 microns in size were sampled in cell-culture medium using an SKC Biosampler connected to a pump operating at 12 lpm. Samples were conserved frozen at -20ºC until analysis. Submerged-cell cultures using the commercially-available A549 cell line were used for the in-vitro assays, where cell viability and generation of reactive-oxygen species (ROS) were assessed. Preliminary results evidenced a relatively large variability across samples in terms of cell viability, with reductions ranging between <5% and up to 60% after 2-hour exposures. Results suggested that the initial INP concentration in the samples may play a relevant role in the results, as in highly concentrated samples nanoparticles may interfere with the cellular uptake of the Alamar Blue dye used and, subsequently, on fluorescence results. ROS generation was detected increasingly over time during the test period (1-4 hours). Readings obtained after 3-4 hour became mostly stable. Finally, these results provide the baseline for the subsequent assessment of the expected reduction in INP concentrations and toxicity resulting from the implementation of risk mitigation measures, which will focus on a custom-designed air filtration system developed in the framework of this project.