Exposure to acetone. Uptake and elimination in man.

Eight male subjects were exposed to acetone vapor on two occasions for 2 h in the laboratory. On the first occasion they were exposed to about 1,300 mg/m3 during rest and on the second occasion to about 700 mg/m3 during rest (30 min) and exercise at different work loads on a bicycle ergometer (90 min). The total uptake of acetone was 0.6--1.2 g, and the relative uptake was about 45%. The concentration of acetone in alveolar air was 30--40% of that in the inspiratory air, and it was not affected by exposure time or work load. The concentration of acetone in blood increased continuously with increased uptake during exposure, and there was no tendency towards equilibrium. The half-time of acetone in alveolar air as about 4 h, and in venous and arterial blood it was about 6 and 4 h, respectively. The highest concentrations of acetone in urine were measured 3--3.5 h after exposure. The elimination of acetone via the lungs corresponded to about 20% of the total uptake. Only about 1% of the uptake was excreted via urine.