Biomonitoring of Occupational Exposure to Styrene

Abstract

To assess the most suitable biological indicators of styrene exposure, a comparison was made between air concentrations of the solvent and biological data in a group of 20 workers using polyester resins. The 8-hour styrene TWA was determined with personal sampling pumps and activated charcoal tubes, using four tubes to obtain four 2-hour samples over the workshift for each subject. The TWA values ranged from 17 to 199 mg/m³. A significant correlation was found between styrene TWA exposure and urinary concentrations of mandelic acid (MA) and phenylglyoxy lie acid (PGA) at the end of the workshift (for MA, r = 0.73; for PGA, r = 0.64; for MA + PGA, r = 0.74). The correlation was even better between styrene TWA and metabolites in the urine collected on the next morning (for MA, r = 0.84; for PGA, r = 0.78; for MA + PGA, r = 0.86). Regression analysis showed that a styrene exposure level of 215 mg/m³ corresponded to an excretion of metabolites (MA + PGA) of 1054 mg/g creatinine at the end of the workshift and of 418 mg/g creatinine the next morning. Styrenemia, determined at the end of the workshift in only 17 workers, appeared to be well correlated with exposure (r = 0.74), particularly for the last two hours of workshift (r = 0.90). In 11 cases in which the styrene TWA concentrations were simultaneously determined with passive dosimeters, a good correlation was also found between exposure and biological data. The correlation coefficients between styrene TWA and the biological indicators were better when considering only the six workers with almost constant levels of exposure during the workday. The authors conclude that total metabolites (MA + PGA) in the next morning urinary samples are the most reliable biological indicators of styrene exposure, especially in plants where there is a high variability in the environmental styrene concentration or in the individual exposure during the workday. Bartolucci, G. B.; De Rosa, E.; Gori, G. P.; Chiesura Corona, P.;Perbellini, L; Brugnone, F.: Biomonitoring of occupational exposure to styrene.