Deposition of polyethylene micro- and nano-plastics is associated with accumulation of cadmium in lungs of smokers: A pilot study.

Airborne micro- and nano- plastics (MNPs) are emerging environmental toxicants which may affect lung cellular functions. Deposition of MNPs in lungs of susceptible individuals e.g. smokers, is not known. We determined the deposition of MNPs in the lungs of smokers and non-smokers. Lung tissues from age and sex-matched smokers (n = 9) and non-smokers (n = 10) were analyzed to quantify: (a) microplastic levels using pyro-GC/MS, and (b) heavy metal accumulation using ICP-MS, given the synergistic environmental effects of these pollutants. Py-GC/MS analysis showed a relatively higher level of MNPs in the lungs of smokers (43.67 mcg/gm) as compared to non-smokers (34.53 mcg/gm). We observed a significant increase in the levels of polyethylene (PE; q = 0.0128), polyvinyl chloride (PVC; q = 0.0013) and polyurethane (PU; q = 0.0485) polymers in the lungs of smokers. Pairwise comparisons of elemental analyses results found an increase in the levels of cadmium (Cd) in the lungs of smokers. Importantly, we observed a strong association (R2 = 0.6392; p = 0.005) between the amounts of accumulated PE and levels of Cd in the lungs of non-smokers versus smokers. Overall, our results show a positive correlation between bioaccumulation of polyethylene (PE) and cadmium (Cd) in the lungs based on smoking status.