Research Grants Program Office

Introduction

Environmental exposure to lead (Pb) and cadmium (Cd) are risk factors for adverse health outcomes in children and adults. This study examined whether thirdhand smoke residue contributes to Pb and Cd in settled house dust.

Methods

Participants were 60 multiunit housing residents in San Diego, California. All had indoor smoking bans during the study period, and 55 were nonsmokers. Wipe samples from different surfaces and vacuum floor dust samples were analyzed for nicotine, a marker of thirdhand smoke, and for Pb and Cd using liquid chromatography-triple quadrupole mass spectrometry and inductively coupled plasma-mass spectrometry, respectively.

Results

Examined in each sample type separately, Pb and Cd loadings were significantly correlated (r = 0.73, vacuum floor dust; 0.52, floor wipes; 0.72, window sill/trough wipes; all p < 0.0025). Pb and Cd loadings from different sample types were not correlated (all p > 0.30). Nicotine loading in dust was significantly correlated with Pb and Cd loading in dust (r = 0.49 for Pb; r = 0.39 for Cd, all p < 0.0025). Pb and Cd loadings on floor or window surfaces, showed no association with nicotine loading in dust, on floors, or on furniture (all p < 0.30).

Conclusions

Tobacco smoke is a likely source of Pb and Cd that accumulates in settled house dust in multiunit housing, suggesting that Pb and Cd are constituents of thirdhand smoke that lingers long after smoking has ended.