Seven male subjects were exposed to 210 mg/m³ of styrene in inspired air during 30 min at rest and three 30-min periods of work on a bicycle ergometer at intensities of 50, 100 and 150 W. The uptake in the organism was measured by the Douglas bag technique. The mean uptake was 490 mg, corresponding to 63% of the amount inspired. During the last 30-min period, the uptake ,in the organism was 5-6 times higher than during the first period at rest. The elimination of styrene by the airways during 19 h after the exposure was estimated to be about 3% of the amount retained in the body during exposure. Needle biopsy of subcutaneous adipose tissue was performed on all the subjects before exposure and 0.5, 2, 4 and 20-24 h a~ter the exposure. In addition, four of the men were subjected to biopsies during the 1-2 weeks following exposure. The concentration of styrene in adipose tissue was deteI1IIlined by gas chromatography after evaporation into nitrogen at a high temperature. About 24 h after the exposure the mean concentration of styrene in adipose tissue was on about the same level as 2-4 h after exposure, i.e., about 3.5 mg/kg. Retention of styrene in adipose tissue was noticed as late as 13 d after the short exposure at a concentration in inspired air corresponding to the Swedish threshold limit value. The estimated half-life of the concentration of styrene in adipose tissue was 2-4 d. In spite of the rapid metabolism of styrene, industrial exposure is considered to be accompanied by the risk of accumulation in adipose tissue because of the slow elimination rate.

Key terms adipose tissue; adipose tissue concentration; alveolar air; body fat; concentration; distribution; elimination; exercise; exposure; man; rest; styrene; subcutaneous adipose tissue; uptake