Influence of evaporation and solvent mixtures on the absorption of tolueneand n-butanol in human skin in vitro

The influence of forced ventilation on the percutaneous absorption of butan ol and toluene,vas studied in vitro, Human skin was exposed to the neat sol vents and the solvents in binary mixtures with each other and in ternary mi xtures with chloroform:methanol. The exposure,vas either unventilated or ve ntilated with various flow rates. At the ventilated exposure the skin absor ption of all solvents and solvent mixtures was markedly! reduced compared t o unventilated exposure. Exposure with solvent mixtures increased the amoun ts of solvent absorbed as well as absorption rates. The absorption of the b utanol component was most influenced. Increase in absorption was 11 to 9 ti mes depending on whether toluene or chloroform/methanol, was cosolvent, The re was also an interindividual variation of absorption rate, varying,with a factor of 3.5 for toluene and 4.3 for n-butanol within the 3 skin donors u sed. Skin absorption of volatile organic solvents at continuous ventilated condi tions is related to their, volatility and to the ventilation rate. A sufficient workplace ventilation is an important occupational hygienic me asure not only to reduce exposure cia respiration but to reduce absorption via the skin of volatile compounds as well. (C) 2000 British Occupational H ygiene Society, Published by Elsevier Science Ltd, All rights reserved.