Determination of urinary mandelic and phenylglyoxylic acids in styrene exposed workers and a control population

Styrene is rapidly metabolized in humans to mandelic () and phenylglyoxylic acids (P) which are excreted in urine. The present study investigates a gas chromatographic technique for measuring urinary concentrations of MA and PGA of workers exposed to styrene, compares the urinary concentrations of metabolites with time-weighted average air exposures to styrene and determines the levels of these metabolites in a population of workers not exposed to styrene. Post-shift urine specimens were obtained from a group of workers exposed to styrene in the reinforced plastic industry and from a control group. High positive correlation was found between post-shift urinary concentrations of metabolites and 8-hour TWA styrene exposure. Both MA and total metabolites (MA + PGA) gave correlation coefficient values of 0.96, p less than 0.0001. The mean MA excretion for the control groups was 6 mg/L. Determination of the concentration of these metabolites in a post-shift urine provides an effective means of estimating and monitoring human exposure to styrene.