DNA-ADDUCTS IN COAL-MINERS - ASSOCIATION WITH EXPOSURES TO DIESEL-ENGINE EMISSIONS

The potential carcinogenic effects of exposure to diesel engine emissi ons (DEE) are of growing concern. Due to the use of diesel equipment i n underground mines, DNA adducts in peripheral blood mononuclear cells have been measured using the P-32-postlabelling technique in workers from two coal mines (A, B) in NSW, Australia, before and after a perio d of more intense exposure (long wall change out, LWCO). DNA adducts w ere readily detected in all workers. At Mine A, in the 89 participants before LWCO, no significant difference was found among the groups cat egorized by exposure levels. However, significantly higher concentrati ons of total DNA adducts were observed in the specific job categories, 'miners and loadmen', and 'machinemen, drivers and shiftmen' and in t he smoking group. On comparing total DNA adducts before and after LWCO in a small number of workers, a significant increase was also found. At Mine B, before or after LWCO, the total DNA adduct levels showed no significant difference among groups categorized by exposure condition s, smoking status, job categories and job time length. However, the to tal DNA adducts for the 61 subjects were significantly increased (geom etric means) from 297 to 389 amol mu g(-1) DNA after LWCO (p < 0.0001, paired t test). Some individual adducts were also elevated to a great er extent (p < 0.05, paired non-parametric test, Wilcoxon signed rank test). Furthermore, using generalized estimating equations for adjusti ng all factors across the observation period, no particular factor sho wed any significant interactive effects. Given the association of expo sure to DEE with lung cancer and the apparent increase in adducts duri ng a period of intense DEE exposures it would be prudent to pay partic ular attention to keeping exposures as low as possible, especially dur ing LWCO operations.