[Investigations on the correlation between vinyl chloride (VCM)-uptake and excretion of its metabolites by 15 VCM-exposed workers. II. Measurements of the urinary excretion of the vcm-metabolite thiodiglycolic acid ].

Fifteen workers employed in a PVC producing plant were investigated concerning their individual vinyl chloride (VCM) exposure and the urinary excretion of the VCM metabolite thiodiglycolic acid (TdGA). The urine concentrations found were in the range 0.94-20.4 microgram/ml. These could be compared with exposure data calculated from VCM air analyses performed by personal air sampling and corrected with respect to the exposure times of the workers. The amounts of TdGA excreted within 24 h were correlated with the effective VCM body concentrations calculated from the exposure data as mean values for 12 h periods (Spearman coefficient P=alpha less than 0.005). This correlation resembles a function of the Michaelis-Menten type. It could be shown that during short exposure periods of less than 5 min, the metabolite formation in relation to the exposure data was lower than during longer periods of exposure although, as would be expected, there were some fluctuations of the exposure level. Therefore, the VCM body concentrations could not normally reach steady state values.