Assessment of dermal exposure--empirical models and indicative distributions

The Health and Safety Executive embarked upon a program of work to address the issue of exposure to nonagricultural pesticides in the United Kingdom. Early on it became clear that the primary route of exposure was via the skin. Empirical dermal exposure models have been developed which allow estimates of potential dermal exposure to be derived from distributions of rate of contamination with in-use formulations during typical use conditions in the workplace. Estimates of actual dermal exposure (what gets onto the skin) may also be anticipated and used in quantitative risk assessment to inform product registration. The key interpreted data from the empirical models are presented. Data are presented for six models. Separate summary data are presented for exposure to the body, hands, and feet. In the case of hand exposure, data are presented, in some cases, for contamination arising from wearing used (previously worn, of unknown history) and clean protective gloves. This article proposes a mechanism for addressing exposure assessment where little or no direct dermal exposure data are available--the indicative distribution approach. The empirical distributions of rate of contamination have been studied to seek commonalities which may allow the construction of a universal tool for use in screening level risk assessment. A simple 12-box matrix is proposed.