Penetration of chromium in intact human skin in vivo.

Graphite furnace atomic absorption spectroscopy was modified to permit analysis of solid material, thereby fully utilizing the high sensitivity of the method. Tangential sections of biopsies from skin tested epicutaneously with K2Cr2O7 were analyzed for the content of chromium 5, 24, and 72 hr after application of the test substance in various concentrations, either in petrolatum or in water. The concentration of chromium as a rule showed 2 maxima, one at the dermal-epidermal junction and the other in upper mid-dermis. The content of chromium was of the same order of magnitude at all 3 times after application. This indicates that a steady state is reached already after 5 hr and that penetration is continuing at 72 hr. The chromium content in normal skin was 0.4-2 ppm. K2Cr2O7 in petrolatum penetrated to a greater extent than in water. The relative penetration of chromium was lower for 0.5% concentration than for 0.05%. A complex of chromium and glycine was found to penetrate into the skin but to a lower extent than K2Cr2O7. It also elicited a positive epicutaneous test reaction in 1 out of 2 individuals hypersensitive to chromium.