Kinetics of urinary excretion and effects on colour vision after exposure to styrene

We evaluated the influence of the body burden of styrene on biological indices of exposure and the effects of this solvent on colour perception. The exposure of 19 workers was followed during a working week by personal sampling and biological monitoring. Although no significant difference in daily exposure was observed, pre-shift values of urinary styrene and urinary mandelic acid increased significantly during the week, and the regression line between external dose and biological exposure indices changed correspondingly. These data suggest that body burden can influence the results of biological monitoring of styrene. The effect of styrene on colour vision was evaluated in two further groups: 73 exposed workers and 53 referents and 36 pairs of workers and controls. A dose-related impairment was observed, which appeared to be synergistic with age and was not significantly improved by a one-month interruption of exposure. Our data show the need to improve biological monitoring of exposure to styrene and, in particular, to establish dose-effect and dose-response relationships between exposure and early effects. Urinary excretion of styrene and colour vision assessment represent, respectively, promising indices of exposure to and an effect of styrene.