2-Naphthol levels and genotoxicity in rubber workers

Urinary bladder cancer is a historical disease of rubber workers often been associated with exposure to aromatic amines such as 2-naphthylamine. While exposure to these compounds has decreased markedly over time, the bladder cancer risk has not decreased in direct proportion. Polycyclic aromatic compounds (PAC) are candidates for urinary bladder cancer causation. We determined pre- and post-exposure urinary levels of 2-napthol (2NAP), the major metabolite of a model volatile PAC, in a group of non-smoking rubber workers. Pre- and post-exposure urine samples were collected from 43 non-smoking workers. Overall mean post-shift 2-naphthol levels were increased (13.95 ± 28.4 μg/l), but non-significantly compared to samples collected pre-exposure (7.97 ± 22.1 μg/l; p=0.29). The greatest difference was observed in the curing department where post-exposure samples were 4.5 fold higher, post shift samples were significantly higher in production workers as compared to non-production workers (p=0.02). Levels of 2NAP were not correlated with levels of carcinogen-DNA adducts in exfoliated urothelial cells nor with other estimates of exposure or effect. These data suggest that post-shift urinary 2NAP levels are increased, particularly in the curing department. However, the differences were not significantly different overall and urinary 2NAP levels did not predict the level of carcinogen DNA adducts in exfoliated urothelial cells.