Basis for skin notation. Part 1. Dermal penetration data for substances om the Swedish OEL list

Abstract

Johanson G & Rauma M. Basis for skin notation. Part 1. Dermal penetration data for substances on the Swedish OEL list. Arbete och Hälsa 2008;42:2.

The aim of this report is to review the published data on dermal penetration of workplace chemicals, as a basis for assignment of skin notations. Short chapters describe the anatomy of the skin, the skin as a diffusion barrier, Fick’s law of diffusion, factors affecting dermal penetration and methods to assess dermal penetration. The major part of the report is devoted to compilation of data assessment of dermal penetration (fluxes and permeability coefficients) for 165 substances corresponding to 150 entries listed in the Swedish ordinance (AFS 2005) on Occupational Expsoure Limits (OELs). The compilation covers all 117 substances marked with an “H” in the ordinance and, in addition, 50 substances that have not been given a skin notation. The compiled data can be used in future revision of skin notations. An analysis of the data shows that quantitative information on dermal penetration is lacking for 53 or about one third of the 165 substances. For those who have quantitative data, a variety of species and experimental techniques have been used. There is a trillion-fold (1012) span in permeability coefficients between the substances. Moreover, for many chemicals with several experimental data sets on permeability, there is a huge intra-chemical span, sometimes several orders of magnitude. In these cases, a preferred study was selected, mainly based on the following criteria: human skin, in vivo studies, neat liquid, water as vehicle and infinite or large dose were preferred over animal skin, in vitro studies, vapor or diluted liquid, other vehicles and low dose, respectively. Notably, more than one third of the chemicals with high skin permeability and with a dermal/inhalation ratio higher than 0.1 according to the ECETOC criteria (1993) lacks a skin notation. This suggests a need for revision of all substances, including those without a skin notation, in the Swedish list.