DNA-DAMAGE IN MONONUCLEAR BLOOD-CELLS OF METAL WORKERS EXPOSED TO N-NITROSODIETHANOLAMINE IN SYNTHETIC CUTTING FLUIDS

In 28 smoking and 37 non-smoking male metal workers from 7 small to me dium sized plants the genotoxic effect caused by the occupational expo sure measured as DNA single strand breaks in the peripheral mononuclea r blood cells was investigated. Metal workers using synthetic cutting fluids are possibly exposed to the carcinogenic N-nitrosodiethanolamin e (NDELA). In this investigation NDELA was detected in the air of the working halls in a concentration up to 1000 ng/m(3) and in the cutting fluids in a concentration up to 135 mg/l (mean values per plant). Wor kers staying in rooms with a mean concentration of NDELA in the air of about 1 mu g/m(3) revealed two times more DNA strand breaks than work ers staying in an environment with less than 50 ng/m(3) of NDELA (p < 0.01). Non-smoking workers with more than 4.5 h contact to cutting flu ids per day showed an 1.5 times higher mean level of DNA strand breaks than their nonsmoking colleagues having had less than 4.5 h contact t o cutting fluids (p < 0.02). Also workers having had work place-relate d complaints showed a statistically significantly higher level of DNA strand breaks compared to workers with no or no work place-related com plaints. No significant correlation was obtained between the extent of DNA damage and the estimated extent of skin contact or the concentrat ion of NDELA found in the cutting fluids. Therefore, for workers in th is investigation NDELA incorporated by inhalation is probably more rel evant for genotoxic damage than NDELA resorbed by skin. An increased l evel of DNA damage was found in metal workers depending on the concent ration of NDELA in the air of the work places. However, without furthe r investigations it cannot be excluded that also other concomitant age nts in the environment were responsible for the observed genotoxic eff ect.