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 0.36-2.25 pg World Health Organization-Toxic Equivalent (WHO-TEQ) Nm(-3) (average 1.01 pg WHO-TEQ Nm(-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 3.34-18.64 pg WHO-TEQ g(-1) (average 8.25 pg WHO-TEQ g(-1)), which were lower than those just outside the factory (average 16.13 pg WHO-TEQ g(-1)). Furthermore, a cohort study of workers in this factory with average follow-up of 24.52 years 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.