GENOTOXIC RISK FOR HUMANS DUE TO WORK PLACE EXPOSURE TO ETHYLENE-OXIDE - REMARKABLE INDIVIDUAL-DIFFERENCES IN SUSCEPTIBILITY

Single strand breaks of DNA of peripheral mononuclear blood cells from 97 male and female workers occupationally exposed to ethylene oxide were analysed by the alkaline elution method. These individuals were occupied with the sterilization of medical devices in hospitals and in commercial plants. Ethylene oxide in the air of the working areas was detected up to a maximal concentration of 16.5 mg/m(3) calculated as 4-h time-weighted average (4h TWA). Mean value was 1.47+/-0.52 mg/m(3) (1 mg/m(3) = 0.55 ppm). Compared to the mean elution rate of the DNA from non-smoking workers exposed to air concentrations of ethylene oxide below the detection limit of 0.1 mg/m(3) (4h TWA) the non-smokers working in rooms with a concentration of ethylene oxide between 0.5 mg/m(3) and 2 mg/m(3) showed a statistically significant (P < 0.05) 119% higher mean elution rate and even for the non-smokers exposed to 0.1-0.5 mg/m(3) of ethylene oxide a statistically significant (P < 0.05) 53% higher mean elution rate was observed. For smokers a similar tendency was found but the increase in elution rates in response to the external exposure was smaller than in non-smokers and no statistical significance was obtained. According to their sensitivity to ethylene oxide the non-smoking workers could be classified into two subpopulations. In the majority of the non-smokers (67%) approximately 5-fold more DNA strand breaks were induced by ethylene oxide than in the other non-smokers. A lowest detectable effect level could only be specified for non-smokers. For the ''higher sensitive'' group the lowest detectable effect level in an examination of a single individual was calculated to be 0.6 mg/m(3) ethylene oxide in the air (4h TWA). For the ''lower sensitive'' group a lowest detectable effect level was calculated to be 3.5 mg/m(3).