The effects of heavy metals and their interactions with polycyclic aromatic hydrocarbons on the oxidative stress among coke-oven workers

Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are predominate toxic constituents of particulate air pollution that may be related to the increased risk of cardiopulmonary events. We aim to investigate the effects of the toxic heavy metals (arsenic, As; cadmium, Cd; chromium, Cr; nickel, Ni; and lead, Pb), and their interactions with PAHs on oxidative stress among coke-oven workers. A total of 1333 male workers were recruited in this study. We determined their urinary levels of As, Cd, Cr, Ni, Pb, twelve PAH metabolites, 8-hydroxydeoxyguanosine (8-OHdG), and 8-iso-prostaglandin-F2 alpha (8-iso-PGF2 alpha). Multivariate linear regression models were used to analyze the effects of these metals and their interactions with PAHs on 8-OHdG and 8-iso-PGF2 alpha levels. It was found that only urinary As and Ni showed marginal or significant positive linear dose-dependent effects on 8-OHdG in this study population, especially among smokers (beta = 0.103, P = 0.073 and beta = 0.110, P = 0.002, respectively). After stratifying all participants by the quartiles of Sigma OH-PAH, all five metals showed linear association with 8-OHdG in the highest quartile subgroup (Q4) of Sigma OH-PAHs. However, these five urinary metals showed significantly consistent linear associations with 8-iso-PGF2 alpha in all subjects and each stratum. Urinary Sigma OH-PAHs can significant modify the effects of heavy metals on oxidative stress, while co-exposure to both high levels of Sigma OH-PAHs and heavy metals render the workers with highest 8-OHdG and 8-iso-PGF2 alpha (all P-interaction <= 0.005). This study showed evidence on the interaction effects of heavy metals and PAHs on increasing the oxidative stress, and these results warrant further investigation in more longitudinal studies. (C) 2015 Elsevier Inc. All rights reserved.