Exposure to toluene: uptake, distribution and elimination in man

Twelve male subjects were exposed to a toluene concentration of about 300 mg/m3 in the inspiratory air during rest and/or physical exercise on a bicycle ergometer. Each subject was exposed during four consecutive 30-min periods. The uptake of toluene was about 50% of the inspired amount at rest, with a decrease to about 30% at a work load of 150 W during the fourth period. The total uptake of toluene during 2 h of work at 50 W was about 2.4 times higher than at rest. There was a close linear correlation between the alveolar and arterial concentrations of toluene, both during and after exposure. The means of the exhaled amounts of unchanged toluene during the first 20 h after exposure ranged between 7 and 14% of the amount taken up. The urinary excretion of hippuric acid indicated an influence of food, especially at low uptake levels.