Measurement of percutaneous uptake of 2-methoxy ethanol vapor in humans

Absorption of vapors through shin has been largely ignored in occupational health, although for ethylene glycol ethers this route of exposure could be more important than inhalation. We used an automated concentration and hum idity controlled system to measure real-time percutaneous absorption of 2-m ethoxy ethanol (ME) vapor in seven volunteers, The exposure concentration ( 300 +/- 10 ppm or 25 +/- 0.5 ppm), humidity (80 +/- 2%), and temperature (2 7.5 +/- 0.5 degrees C) were controlled throughout the experiments, Uptakes during 4-hour single-arm exposure at 25 ppm and 300 ppm were 7.0 mg and 65. 3 +/- 25.0 mg, respectively, with corresponding uptake rates of 1.36 mu g/c m(2)/hr and 13.2 +/- 5.0 mu g/cm(2)/hr. Percutaneous absorption was consist ent and unsaturated during exposure. Because the permeability constant of M E vapor (14.0 +/- 5.3 cm/hr) was much higher than that of many widely used organic chemicals, we concluded that vapor absorption through skin is a sig nificant contributor to overall ME exposure.