Bronchoalveolar Lavage as a Diagnostic Window into Human Exposure to Microplastics and Associated Lung Changes

Microplastics are emerging airborne pollutants increasingly implicated in respiratory health risks. Although ingestion has been widely studied, inhalation of microplastics and their potential pulmonary impact remain underexplored. Bronchoalveolar lavage (BAL) provides a minimally invasive diagnostic technique for detecting inhaled particles and assessing associated inflammatory changes.

This cross-sectional study was conducted among 60 adult patients undergoing diagnostic bronchoscopy for non-infective pulmonary complaints. BAL fluid was collected and filtered to detect microplastics using polarized light microscopy and Fourier-transform infrared (FTIR) spectroscopy. Cytological examination and cytokine analysis (IL-6, TNF-α) were also performed. Data were statistically analyzed using SPSS v25, with significance set at P < 0.05.

Microplastics were detected in 70% of BAL samples, with polyethylene and polypropylene being the most common types. The mean microplastic count was 6.4 ± 3.1 particles per 100 mL BALF. Individuals with detectable microplastics showed significantly higher macrophage (65.4% vs. 58.6%, P = 0.012) and neutrophil (18.2% vs. 12.4%, P = 0.003) percentages in BAL cytology, alongside elevated IL-6 and TNF-α levels (P < 0.001). Lymphocyte proportions were relatively lower in exposed individuals (P = 0.017).

Bronchoalveolar lavage is a valuable tool for detecting pulmonary microplastic exposure and related inflammatory changes. These findings underscore the potential health risks posed by airborne microplastics and support the need for environmental and occupational health interventions.