First evidence of microplastics isolated in European citizens’ lower airway

Microplastics (MPs) have been detected in all environmental locations, including the atmosphere. However, few studies have investigated the presence of airborne MPs in the human respiratory system. Our research purpose was to investigate these pollutants in the lower human airways of 44 adult European citizens, using bronchoalveolar lavage fluid (BALF) collection as a minimally invasive method, that enables the detection of these pollutants in living patients. We studied the relationship between the patients’ life habits and physiological parameters, based on background information and medical and occupational history, and the concentration of MPs isolated from their respiratory systems. Our results indicate that most MPs were in the form of microfibers (MFs) (97.06%), with an average concentration of 9.18 ± 2.45 items/100 mL BALF, and only 5.88% (0.57 ± 0.27 items/100 mL BALF) were particulate MPs, without a significant relationship with environmental, physiological, or clinical factors. The average size was 1.73 ± 0.15 mm, with the longest dimension (9.96 mm) corresponding to a polyacrylic fiber. Taken together, the results demonstrated the occurrence of MPs in the lower human airway, although more studies are necessary to elucidate the negative effects these pollutants could induce in the human respiratory system and its associated diseases.We wish to express our sincere appreciation to José V. Navarro for safe BALF samples transportation form HGUE to UPCT and back, as well as to the HGUE Pneumology Service, particularly to Sandra Ruiz, Lucía Zamora, Maria José Soler, Asunción Guillén, and Carmen María Vidal for their help in BALF samples collection and investigation support. This work was finacially supported by grant 20268/FPI/17 from Fundación Séneca assigned to Dra. Sonia Olmos, as well as by Project Number 6627/21IQA signed between FISABIO and Technical University of Cartagena, with financial help from Sociedad Valenciana de Neumología