Characterization of microparticles derived from waste plastics and their bio‐interaction with human lung A549 cells.

Microplastics (MPs) represent a worldwide emerging relevant concern toward human and environmental health due to their intentional or unintentional release. Human exposure to MPs by inhalation is predicted to be among the most hazardous. MPs include both engineered, or primary MPs, and secondary MPs, materials obtained by fragmentation from any plastic good. The major part of the environmental MPs is constituted by the second ones that are irregular in size, shape and composition. These features make the study of the biological impact of heterogenous MPs of extremely high relevance to better estimate the real toxicological hazards of these materials on human and environmental organisms. The smallest fractions of plastic granules, relying on the micron‐sized scale, can be considered as the most abundant component of the environmental MPs, and for this reason, they are typically used to perform toxicity tests using in vitro systems representative of an inhalation exposure scenario. In the present work, MPs obtained from industrial treatment of waste plastics (wMPs < 50 μm) were investigated, and after the physico‐chemical characterization, the cytotoxic, inflammatory and genotoxic responses, as well as the modality of wMPs interactions with alveolar lung cells, were determined. Obtained results indicated that, at high concentrations (100 μg/ml) and prolonged exposure time (48 h), wMPs affect biological responses by inducing inflammation and genotoxicity, as a result of the cell–wMP interactions, also including the uptake of the smaller particles. The toxicity of waste microplastics (wMPs < 50 μm), recovered from industrially recycled plastic granules, was evaluated by using an in vitro model of the lung (A549 cell line), in order to understand the biological outcomes induced by the inhalation of microplastics. Data showed that a prolonged (48 h) exposure to wMPs (100 μg/ml) induced cell viability reduction, inflammation and genotoxicity, as results of lung cell and wMPs interactions. [ABSTRACT FROM AUTHOR]