Nickel Dermal Bioavailability in Pig Skin Increased by a Chemical Mixture: Role of Gender

Exposure to chemical mixtures is more common than exposure to a single chemical. Skin is the largest tissue in the human body and is an important route of exposure to chemical mixtures. The aim of this study was to assess the effect of toluene, trichloroethylene (TCE) and phenol on the dermal bioavailability of nickel. All four compounds are prevalent in the environment, at industrial facilities, and at hazardous waste sites. An in vitro approach was employed which utilized radiotracer methodology and a modified Teflon flow-through diffusion cell system to measure the amount of chemical which penetrated through or became bound to dermatomed male or female pig skin. In males, there was almost a 2-fold increase in the total cumulative percentage of radioactivity in the receptor fluid after treatment with the mixture compared to nickel alone. In females, significantly more radioactivity (2-fold) penetrated into receptor fluid when skin was treated with the chemical mixture of nickel versus nickel alone. The chemical mixture produced a significant increase in the total penetration and the amount of nickel that became bound to skin relative to nickel alone in both sexes. Also, more radioactivity remained loosely adsorbed to skin and could be easily washed off of § Corresponding Author: Mohamed S. Abdel-Rahman, Ph.D., F.C.P., B.C.F.E., Pharmacology and Physiology Department, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, 185 South Orange Avenue, Newark, New Jersey, USA, 07103-2714; Tel: 973-9793146; Email: [email protected] Abdel-Rahman and Turkall: Nickel Dermal Bioavailability Increased by a Chemical Mixture Produced by The Berkeley Electronic Press, 2011 30 Contaminated Soils, Sediments, Water and Energy the skin surface when nickel was applied alone rather than in combination to male or female skin. However, the total penetration and the radioactivity in the skin matrix were significantly higher in females than in males treated with the nickel mixture. This study revealed that the bioavailability of nickel to skin is significantly higher when administered in the chemical mixture compared to nickel alone. Furthermore, females are at greater risk than males from dermal exposure to the nickel mixture.