Biomarkers for exposure to ambient air pollution - Comparison of carcinogen-DNA adduct levels with other exposure markers and markers for oxidative stress

Human exposure to genotoxic compounds present in ambient air has been studi ed using selected biomarkers in nonsmoking Danish bus drivers and postal wo rkers. A large interindividual variation in biomarker levels was observed. Significantly higher levels of bulky carcinogen-DNA adducts (75.42 adducts/ 10(8) nucleotides) and of 2-amino-apidic semialdehyde (AAS) in plasma prote ins (56.7 pmol/mg protein) were observed in bus drivers working in the cent ral part of Copenhagen, Denmark. In contrast, significantly higher levels o f AAS in hemoglobin (55.8 pmol/mg protein), malondialdehyde in plasma (0.96 nmol/ml plasma), and polycyclic aromatic hydrocarbon (PAH)-albumin adduct (3.38 fmol/mu g albumin) were observed in the suburban group. The biomarker levels in postal workers were similar to the levels in suburban bus driver s. In the combined group of bus drivers and postal workers, negative correl ations were observed between bulky carcinogen-DNA adduct and PAM-albumin le vels (p = 0.005), and between DNA adduct and gamma-glutamyl semialdehyde (G GS) in hemoglobin (p = 0.11). Highly significant correlations were found be tween PAM-albumin adducts and AAS in plasma (r = 0.001) and GGS in hemoglob in (p = 0.001). Significant correlations were also observed between urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine and AAS in plasma (p = 0.001) and PAM- albumin adducts (p = 0.002). The influence of the glutatione S-transferase (GST) M1 deletion on the correlation between the biomarkers was studied in the combined group. A significant negative correlation was only observed be tween bulky carcinogen-DNA adducts and PAM-albumin adducts (p = 0.02) and b etween DNA adduct and urinary mutagenic activity (p = 0.02) in the GSTM1 nu ll group, bur not in the workers who were homozygotes or heterozygotes for GSTM1. Our results indicate that some of the selected biomarkers can be use d to distinguish between high and low exposure to environmental genotoxins.