BIOLOGICAL EFFECT MONITORING IN INDUSTRIAL-WORKERS FROM THE CZECH-REPUBLIC EXPOSED TO LOW-LEVELS OF BUTADIENE

Blood samples were collected twice(in 1993 and 1994) from 19 workers e xposed to 1,3-butadiene and 19 matched controls. Three exposed and thr ee control subjects were the same in 1993 and 1994. Personal passive d osimetry was performed in 1993 and twice in 1994 on the day preceding blood sampling. Mean exposure level in 1994 was 1.76 +/- 4.20 ppm (S.D .) and individual exposure levels ranged between 0.012 ppm (detection limit) and 19.77 ppm. Using the clonal assay, geometric mean of hprt m utant frequencies adjusted for cloning efficiency, age and smoking wer e, respectively, 7.85 (+/-7.09) x 10(-6) and 10.14 (+/-9.16) x 10(-6) in pooled (1993 plus 1994) exposed and control subjects. The differenc e was not statistically significant indicating that 1,3-butadiene did not induce a detectable increase in mutations at the hprt locus. A sim ilar result was obtained for the 1994 subjects alone. There was no dif ference between adjusted geometric mean mutant frequencies of exposed and unexposed non-smokers or between exposed and unexposed smokers. An alysis of chromosomal aberration's in lymphocytes from 1994 subjects i ndicated that the percentage of aberrant cells was significantly enhan ced in exposed subjects. In 1993 (data not shown), it was impossible t o demonstrate a significant increase of aberrant cells in subjects exp osed to 1,3-butadiene. Frequencies of micronuclei in cytochalasin-B bl ocked binucleate lymphocytes in exposed and unexposed 1994 subjects we re not significantly different. This was also the case for earlier sam ples analyzed in the same plant. Using the comet assay for 1993 subjec ts, no statistically significant difference was found between the whol e group of exposed and unexposed subjects. This was true for both the comet tail length and the percentage of DNA in the tail. In exposed sm okers, however, the comet tail length was significantly longer than in unexposed smokers. Unexpectedly, in unexposed smokers the tail length was significantly shorter than in unexposed non-smokers. It was also unexpected that the percentage of DNA in the comet tail was significan tly lower in exposed non-smokers than in unexposed non-smokers.