EFFECTS OF METHANOL ON STYRENE METABOLISM AMONG WORKERS OCCUPATIONALLY EXPOSED AT LOW CONCENTRATIONS

A survey was conducted in the second half of a work week on 39 male wo rkers who were occupationally exposed to styrene in combination with m ethanol and methyl acetate during the production of plastic buttons. T ime-weighted average exposure during an 8-h shift to styrene (Sty-A) a nd methyl acetate was monitored by carbon cloth-equipped personal samp lers and to methanol by water-equipped ones. Urine samples were collec ted near the end of the shift and analyzed for mandelic (MA-U) and phe nylglyoxylic acids (PhGA-U) by HPLC. Geometric mean styrene concentrat ion was 12.4 ppm (mu g/g) with the maximum of 46 ppm, whereas the valu es for methanol and methyl acetate in combination were 23.5 ppm and 22 9 ppm, respectively. The relationship of MA-U and PhGA-U with Sty-A wa s examined by linear regression analysis. The equations for the regres sion lines were compared with the results from a previous survey (Iked a et al. 1983) in which workers were exposed only to styrene, and the methods employed were identical with that in the present study. The co mparison showed no evidence to suggest that styrene metabolism is supp ressed by coexposure to methanol and methyl acetate at low concentrati ons below the current occupational exposure limit of 200 ppm.