Exposure to white spirit I. Concentration in alveolar air and blood during rest and exercise ASTRAND, 1., KILBOM, A. and 6VRUM, P. Exposul'l'O to white spirit: T. Concentration in alveolar ail' and blood during rest and exercise. Scand. j. wOTk enviTon. & hea~th 1 (1975) 15-30. Fifteen healthy male subjects were exposed to 1,250 and 2,500 mg/mil of white spirit in inspiratory air during rest and excercise on a bicycle ergometer. The white spirit contained approximately 83 0J0 aliphatic and 17 % aromatic components. The duration of each exposure period was 30 minutes. The pulmonary ventilation, the cardiac output, and the concentration of white spirit (subdivided into aromatic and aliphatic components) in alveolar air, arterial blood, and venous blood were determined during and after exposure. The concentration of aliphatic and aromatic components in alveolar air tended to level off towards the close of each period. The resting level of the aromatic components increased approximately 2.0 times, and that of aliphatic components about 2.5 times, during exercise with increased intensities. The concentration of aliphatic components in arterial and venous blood increased at the start of each expOSure period but tended to level off towards the close of the period. The resting value increased fourfold in work at the highest intensity. However, the concentration of aromatic components rose sharply during each period. The arterial blood concentration was about 15 times higher at the end of exposure during the heaviest exercise intensity than at rest. Pulmonary ventilation appeared to be more important to uptake in arterial blood than to circulation. The results are believed to be due to the differing solubilities of aliphatic and aromatic components in blood. Measurement of the concentration of white spirit in venous or arterial capillary blood is suggested as a biological check on exposure.

and PER OVRUM, M.Sc.! ASTRAND, r., ENGSTROM, J. and OVRUM, P. Exposure to xylene and ethylbenzene: 1. Uptake, distribution and elimination in man. Scand. j. work environ. & health 4 (1978) 185-194. Industrial xylene is a mixture of xylene and ethylbenzene. Twelve male subjects were exposed to industrial xylene in inspired air, six subjects in series I to 870 mg/m S at rest (30 min) and light exercise on a bicycle ergometer (90 min) and six subjects in series II to 435 mg/m S at rest (30 min) and during exercise of increasing work loads (90 min). The mea.surements of xylene uptake were performed continuously wi,th the Douglas bag technique. In both series, about 60 010 of the amount of xylene supplied to the lungs was taken up. In both series, the concentration in alveolar air was relatively low throughout the entire exposure. The relative concentration in alveolar air displayed a linear correlation to the percentage uptake in the lungs. The ratio between the concentration in arterial blood (mg/kg) and alveolar air (mg/l) amounted to 30-40 at the different work loads. The total amount of xylene expired after the exposure was estimated from the alveolar concentration and alveolar ventilation. In series I, with a total uptake of 1.4 g, the subjects expired about 70 mg, i.e., about 5 010. The corresponding value in series II was 40 mg of a total uptake of 1.0 g, Le., about 4 0/0•

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Exposure to methylene chloride. I Its concentration in alveolar air and blood during rest and exercise and its metabolism. by Åstrand I, Övrum P, Carlsson A 1 (1975) 78-94. Fourteen subjects were exposed to about 870 and 1,740 mg/m 3 of methylene chloride in the air during rest and physical exercise on a bicycle ergometer. The duration of each exposure period was 30 min. Each subject was exposed during four periods. The concentration of methylene chloride in the alveolar air increased in the beginning but had a tendency to level off at the end of each period. There was a high correlation between the alveolar and arterial concentration of methyLene chloride. The uptake of methylene chloride was about 55 Ofo of the supplied amount at rest, about 40 Ofo at a work load of 50 W, and about 30 and 35 Ofo at 100 and 150 W, respectively. The concentration of carboxyhemoglobin (COHb) increased both during and after exposure. With exposure to 1,740 mg/m 3 a concentration of COHb in the blood of about 0.85 g/100 ml was reached. This value corresponds to about 5.5 % COHb.