Exposure assessment of hazardous metal elements in laundry dryer lint and preliminary multiroute health risk estimation

Laundry dryer lint has been identified as a potential tool to detect household sources of hazardous metal elements and their environmental and health effects. The primary objective of this study was to characterize the occurrence and distribution of hazardous metals in dryer lint samples. Dryer lint samples (n = 480), consisting of natural, synthetic fibers or a combination of these different types, were analyzed for trace metals of toxicological concern (n = 11) using field portable x-ray fluorescence spectroscopy. The analysis revealed the presence of Sb (n = 250; 48 ± 2.5 μg/g) in the highest concentration in synthetic products and Br (n = 480, 17 ± 3.3 μg/g) in natural products. Lead and arsenic were detected in 32 and four samples at mean concentrations of 8.5 ± 1.2 µg/g and 4.8 ± 0.91 µg/g for Pb and As, respectively. A preliminary estimation of potential human exposure and illustrative exposure estimation via inhalation, ingestion, and dermal contact was also included for illustrative purposes. Because dryer lint represents the materials expelled during the drying process, its composition and potential reuse in households (e.g., recycling into new products) are crucial from an environmental perspective. This study highlights the importance of understanding the sources of these elements in clothing and the implications of metallic nanoparticles and microplastics.