Toluene determination in capillary blood as a biological indicator of exposure to low levels of toluene.

The possibility of evaluating occupational exposure to toluene at low levels (50-150 mg/m3), based on the determination of unchanged substances in capillary blood, was investigated. The volunteers were exposed in a toxicological chamber; during and after exposure venous and capillary blood samples were analysed by gas chromatography using the headspace technique. Toxicokinetic data point out that determination of toluene should be performed in blood samples collected 15-20 min after termination of exposure. The toluene concentration in capillary blood may reflect the toluene dose absorbed during the workshift only in the case of constant exposure. Otherwise, this measurement refers to the rate of toluene absorption, mainly in the last 2 hours of daily exposure.