Cadmium and chromium as markers of smoking in human lung tissue

The pulmonary cadmium (Cd) and chromium (Cr) contents from 45 decreased persons from Northern Finland were determined by plasma emission spectrometry (DCP-AES). These subjects did not have any malignant diseases or known occupational exposure to heavy metals. The pulmonary metal concentrations were compared with smoking history, pulmonary emphysema, age, and occupation. The mean Cd concentrations for the nonsmokers, smokers, and exsmokers were 0.4 (SD +/- 0.4), 3.0 (SD +/- 2.2), and 1.1 (SD +/- 1.0) micrograms/dry wt, and the corresponding values for Cr were 1.3 (SD +/- 0.9), 4.3 (SD +/- 3.3), and 4.8 (SD +/- 4.0) micrograms/g dry wt, respectively. The pulmonary Cr content increased with age and smoking time, but showed no connection with occupation. The Cd content was dependent only on smoking-related variables, increasing with the amount of tobacco smoked. The pulmonary Cd was seen to return to the level of nonsmokers in 21-22 years after cessation of smoking, whereas Cr showed no decreasing tendency with the time since smoking stopped.