Polychlorinated dibenzo-p-dioxins and dibenzofurans and their association with cancer mortality among workers in one automobile foundry factory

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) have been reported as possible carcinogenic hazards to humans. However, epidemiological studies on their carcinogenic roles are limited. The current study was designed to determine the concentrations and characteristics of PCDD/Fs and evaluate their association with cancer mortality in exposed workers in one automobile foundry factory. PCDD/F levels in factory and surrounding environment were analyzed through air and settling dust sampling. The cancer mortalities among workers in this foundry factory were calculated using data from a cohort study. The results showed that the PCDD/F concentrations of air in workplace ranged 0.36–2.25pgWorld Health Organization-Toxic Equivalent (WHO-TEQ) Nm−3 (average 1.01pgWHO-TEQNm−3), which were 1.16–7.26 times higher than those outside the factory. The PCDD/F concentrations of settling dust in the workplace ranged 3.34–18.64pgWHO-TEQg−1 (average 8.25pgWHO-TEQg−1), which were lower than those just outside the factory (average 16.13pgWHO-TEQg−1). Furthermore, a cohort study of workers in this factory with average follow-up of 24.52years showed that cancer was the leading cause of death, with significant elevated mortality (standardized mortality ratio (SMR)=1.70, 95% confidence interval (CI): 1.35–2.13) among workers, when compared with Chinese national mortality. The cancer mortality among front-line workers was increased significantly (adjusted relative risk (RR)=1.73, 95% CI: 1.14–2.60), particularly among melting and casting workers, when compared with that among assistant workers. Our results indicated that there was a dose–response relationship between PCDD/F exposure and cancer mortality among foundry workers. ► PCDD/Fs generated from the automobile foundry process polluted the environment. ► The PCDD/F concentrations in melting furnace areas were the highest in workshops. ► Lung, liver and all cancer mortality in foundry workers increased significantly. ► Relative risk of cancer mortality in melting workers to assistant workers was 2.55. ► Dose–response relationship between PCDD/F exposure and cancer mortality was found.