Toxicity of different light-emitting diode phosphor-dispersed encapsulants exposed by pharyngeal aspiration in mice

• The chemical composition of LED particles depended on the fluorescent color type. • Inhaled LED particles are persistent in the lungs and can migrate to other tissues. • Lithium ions may be closely involved in the formation of lamellar bodies. • Rod-shaped particles may be the main cause of collagen and collagen fibers. • Damaged mitochondria may contribute to the generation and growth of lamellar bodies. As the global use of light-emitting diodes (LEDs) expands, their waste management has become an increasingly important environmental issue. In the current study, potential health impacts associated with the inhalation of non-recycled LED components, particularly phosphor-dispersion encapsulation materials separated from waste LEDs, were identified. Si content was in the order of cool-white LED (CWL), natural white LED (NWL), and warm-white LED particles (WWL), and notable differences in rare-earth and alkaline-earth metals were observed between groups. When aspirated via the pharynx for 28 days (10 and 50 μg/mL), NWL and WWL significantly reduced triglyceride levels, and the three types of LED particles accumulated in lung tissue, affecting the distribution of elements in the heart, brain, and kidneys. Compared to the control group, the three types of LED particles increased the total number of pulmonary cells. They (50 µg/lung) also significantly increased pulmonary CXCL-1 and interferon-gamma levels, whereas the pulmonary macrophage chemoattractant protein-1 alpha level decreased significantly. Interestingly, the formation of lamellar bodies and tubular myelin was prominent in the lung tissues of CWL-treated mice, whereas collagen and collagen fibers were abundantly formed in the lungs of WWL-treated mice. Moreover, the lamellar body structures fused to damaged mitochondria or surrounding lamellar bodies, along with the loss of membrane integrity. Collectively, more intensive and effective recycling strategies for LED waste should be established to prevent potential adverse environmental and human health effects. Given that lamellar bodies and tubular myelin, which are potential initiators of pulmonary fibrosis, were found notably in CWL with the highest lithium content, and that lithium is a major raw material for secondary batteries, in-depth research on the relationship between inhaled lithium ions and pulmonary diseases should be conducted.