DERMAL ABSORPTION OF NEAT AND AQUEOUS VOLATILE ORGANIC-CHEMICALS IN THE FISCHER 344 RAT

Quantification of dermal absorption of volatile organic chemicals (VOCs) from aqueous solutions is required to understand the potential health hazards resulting from skin exposure to these chemicals in contaminated water. Male Fischer 344 rats were dermally exposed (3.1-cm2 dorsal skin) to neat, one-third saturated, two-thirds saturated, or saturated aqueous solutions of 14 VOCs for 24 hr. Blood samples were obtained via indwelling jugular catheters during exposure (0, 0.5, 1, 2, 4, 8, 12, and 24 hr), and analyzed for the VOCs by gas chromatography using headspace analysis. Absorption of the neat VOCs in this series of chemicals decreased as water solubility decreased. Peak blood levels of VOCs attained during exposure for 24 hr to neat chemicals were: 1,2-dichloroethane (135.1 μg/ml), bromochloromethane (113.3 μg/ml), chloroform (51.0 μg/ml), benzene (24.2 μg/ml), tetrachloroethylene (21.1 μg/ml), dibromomethane (18.2 μg/ml), trichloroethylene (11.6 μg/ml), toluene (9.5 μg/ml), xylene (8.8 μg/ml), hexane (8.0 μg/ml), ethylbenzene (5.6 μg/ml), styrene (5.3 μg/ml), carbon tetrachloride (5.0 μg/ml), and 1,1,1-trichloroethane (3.4 μg/ml). Blood levels of 1,2-dichloroethane and benzene continued to increase during the 24-hr exposure to neat chemical, while blood levels of the other neat VOCs peaked within 4 hr and then either decreased or remained about the same for the duration of the exposure. Absorption of VOCs from one-third, two-thirds, or saturated aqueous solutions was rapid, and resulted in depletion of the chemical from the solution although only a small amount of water was absorbed. Blood levels of each VOC were directly related to the exposure concentrations. The rapid appearance of VOCs in the blood from aqueous solutions demonstrates that detectable amounts of VOCs were absorbed during exposure of only about 1% of the skin surface area of the rat. © 1991 Academic Press, Inc.