Benzene percutaneous absorption: dermal exposure relative to other benzene sources.

Skin is one of several exposure routes whereby benzene, a widely distributed environmental contaminant that causes leukemia, enters the body, so accurate predictions of its percutaneous absorption are important for risk assessment. Determining benzene's skin-exposure dose and subsequent absorption is difficult because it has a low boiling point and exists as both liquid and vapor. Industrial and environmental benzene is present as a contaminant in other vehicles/solvents, and its percutaneous absorption is in part dependent upon co-solvent volatility. Co-solvents such as benzene in toluene rapidly evaporate from skin, whereas benzene contaminant in water is retained on skin longer due to water's lower volatility. Co-solvents can also affect benzene-skin partition coefficients; thus, permeability coefficients and percentage doses absorbed can vary many-fold. The exposure situation will determine percutaneous absorption, which, if low, can be overwhelmed by benzene intake from the food we eat and the air we breathe.