Presence of microplastics in human's respiratory system: bronchoalveolar and bronchial lavage fluid

Although microplastics (MPs) have been widely detected in the atmosphere, their presence and deposition patterns within the human respiratory system remain poorly understood. This study aimed to investigate the occurrence and characteristics of MPs in bronchial lavage fluid (BLF) and bronchoalveolar lavage fluid (BALF) of the patients undergoing flexible bronchoscopy and to examine the relation between the amount of MPs and patient's demographic characters. Results of this study revealed that MPs concentrations in BLF and BALF were 1.21 MPs/ml and 1.38 MPs/ml, respectively. Fiber constituting was the predominant morphology in the samples (BLF = 76%, BALF = 72%) and the longest fiber dimension was observed in BLF (2425 μm). Individuals employed in industrial and agriculture exhibited significantly higher MPs concentrations. Based on the µ-Raman results, seven distinct polymer types were identified, as polypropylene (PP), polycarbonate (PC), and polyamide (PA) were the most prevalent. Furthermore, SEM-EDS analysis detected the presence of some heavy metals associated with MPs, including Fe, Zn, and Cr. These results provide evidence for the presence of MPs within the human airway, although further research is warranted to elucidate the entry pathways, potential health impacts, and associated respiratory diseases.