DNA adducts in granulocytes of hospital workers exposed to ethylene oxide.
BACKGROUND
Ethylene oxide (EtO), an important industrial chemical intermediate and sterilant, is classified as a human carcinogen. Occupational EtO exposure in many countries is regulated at 1 ppm (8-hr TWA), but levels of EtO-DNA adducts in humans with low occupational EtO exposures have not been reported.


METHODS
We examined the formation of N7-(2'-hydroxyethyl)guanine (N7-HEG), a major DNA adduct of EtO, in 58 EtO-exposed sterilizer operators and six nonexposed workers from ten hospitals. N7-HEG was quantified in granulocyte DNA (0.1-11.5 microg) by a highly sensitive and specific gas chromatography-electron capture-mass spectrometry method. Cumulative exposure to EtO (ppm-hour) was estimated during the 4-month period before the collection of blood samples.


RESULTS
There was considerable inter-individual variability in the levels of N7-HEG with a range of 1.6-241.3 adducts/10(7) nucleotides. The mean levels in the nonexposed, low (< or =32 ppm-hour), and high (>32 ppm-hour) EtO-exposure groups were 3.8, 16.3, and 20.3 adducts/10(7) nucleotides, respectively, after the adjustment for cigarette smoking and other potential confounders, but the differences were not statistically significant.


CONCLUSIONS
This study has demonstrated for the first time, detectable levels of N7-HEG adducts in granulocytes of hospital workers with EtO exposures at levels less than the current U.S. standard of 1 ppm (8-hr TWA). A nonsignificant increase in adduct levels with increasing EtO exposure indicates that further studies of EtO-exposed workers are needed to clarify the relationship between EtO exposure and N7-HEG adduct formation.
Yong
Lee C
LC
Division of Surveillance, Hazard Evaluations and Field Studies, National Institute for Occupational Safety and Health, CDC, Cincinnati, Ohio 45226, USA. lay77@cdc.gov
Schulte
Paul A
PA
Kao
Chi-Yu
CY
Giese
Roger W
RW
Boeniger
Mark F
MF
Strauss
Gary H S
GH
Petersen
Martin R
MR
Wiencke
John K
JK
D000328:Adult; D018736:DNA Adducts; D005027:Ethylene Oxide / Q000633:toxicity*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D005838:Genotype; D006098:Granulocytes / Q000187:drug effects*; D006147:Guanine / Q000031:analogs & derivatives; D006801:Humans; D008297:Male; D008800:Mexico; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010564:Personnel, Hospital; D010865:Pilot Projects; D014481:United States
D018736:DNA Adducts; C035018:N(7)-hydroxyethylguanine; D006147:Guanine; D005027:Ethylene Oxide