DETERMINATION OF LOW-LEVEL EXPOSURE TO VOLATILE AROMATIC-HYDROCARBONSAND GENOTOXIC EFFECTS IN WORKERS AT A STYRENE PLANT

Objectives-Low exposures to volatile aromatic hydrocarbons and cytogen etic effects in peripheral white blood cells were determined in 25 hea lthy workers employed in different areas of a styrene production plant in the former German Democratic Republic. The results were compared w ith 25 healthy unexposed controls (matched for age and sex) employed i n the same company. Methods-The concentrations of aromatic hydrocarbon s determined from active air sampling in all areas of the factory (sty rene: 73-3540 mu g/m(3) (<0.01-0.83 ppm); ethylbenzene 365-2340 mu g/m (3) (0.08-0.53 ppm); benzene 73-3540 mu g/m(3) (<0.02-1.11 ppm); tolue ne 54-2960 mu g/m(3) (0.01-0.78 ppm); xylenes 12-94 mu g/m(3) (<0.01-0 .02 ppm)) were considerably lower than in the pump house (>4000 mu g/m (3) styrene, ethylbenzene, benzene, and toluene; >500 mu g/m(3) xylene s), which was only intermittently occupied for short periods. Passive personal monitoring, biomonitoring of exhaled air and metabolites (man delic, phenylglyoxylic, trans, trans-muconic, hippuric, o-, m- and p-m ethylhippuric acids, and phenol) in urine samples collected before and after an eight hour working shift was used to assess individual expos ure. Questionnaires and examination of records showed that the histori cal exposure was far higher than that measured. Genotoxic monitoring w as performed by nuclease Pi-enhanced P-32-postlabelling of DNA adducts in peripheral blood monocytes, and DNA single strand breaks, sister c hromatid exchange, and micronuclei in lymphocytes. The content of kine tochores in the micronuclei was determined by immunofluorescence with specific antibodies from the serum of CREST patients. Results-No genot oxic effects related to exposure were detected by DNA adducts or DNA s ingle strand breaks and sister chromatid exchange. The only effect rel ated to exposure was an increase in kinetochore positive micronuclei i n peripheral lymphocytes; the frequency of total micronuclei in periph eral lymphocytes did not change. Smoking was confirmed by measurement of plasma cotinine, and no confounding effect was found on any of the cytogenetic variables. Conclusions-Low occupational exposure to styren e, benzene, and ethylbenzene did not induce alterations of genotoxicol ogical variables except kinetochore positive micronuclei. This is the first reported use of the CREST technique for an in vivo study in occu pational toxicology, which thus could serve as a valuable and sensitiv e technique for toxicogenic monitoring.