RELATIONSHIP BETWEEN DOSE IN-VIVO OF ETHYLENE-OXIDE AND EXPOSURE TO ETHENE STUDIED IN EXPOSED WORKERS

1 In vivo doses of ethylene oxide, arising from ethene exposure, in pl astic industry workers were estimated through hemoglobin adducts. The ethene exposure assessed through person-worn monitors. The metabolic c onversion of ethene to ethylene oxide was estimated from the exposure dose/in vivo dose ratio. 2 Two studies were done: In the first study h emoglobin adducts were determined in samples collected on one occasion in exposed groups and exposure doses were estimated by using exposure data from the hygienic surveillance program. The second study applies a newly developed study design with repeated blood sampling in a few persons combined with a complete personal exposure monitoring during t he study period. This makes it possible to relate adduct formation wit h individual short-time exposure doses, which in theory should overcom e the problems with exposure history dependence of the adduct level in a single blood sample, The results of the second study shows that it is possible, through the proposed method, to utilize occupational expo sure situations for this kind of studies even if the exposure pattern is irregular and highly variable. Both studies show a metabolic conver sion of ethene to ethylene oxide of only 0.5%, which is unexpectedly l ow. 3 The cancer risk associated with the ethene exposure in the highl y exposed group (3.6 p.p.m. 40 h/week) is estimated by applying the ra diation-dose-equivalence approach. The result of this evaluation leads to a risk corresponding to a radiation dose of 4 mSv/year which is ab out a factor 3 below the current dose limit for radiological work reco mmended by ICRP.