Summary

Dermal absorption of pesticides - evaluation of variability and prevention

Several projects describing factors of relevance to variations in dermal absorption of pesticides have during recent years been published by the Danish EPA. To summarize these projects and update them with the most recent literature, a detailed report (Dermal absorption of pesticides – evaluation of variability and prevention) was made. This report was supplemented with a shorter Danish version (Dermal absorption af bekæmpelsesmidler – evaluering af årsager til variation samt forebyggelsesmuligheder) focusing on the main conclusions from the English report.

Variability in dermal absorption following exposure to pesticides depends on individual susceptibility, use of preventive measures, and chemical characteristics of the pesticides.

There are large differences between penetration rates of a chemical through skin from different parts of the body. Likewise, dermal absorption of chemicals is significantly enhanced through skin compromised by minor scrapes, atopic dermatitis, eczema, or by hydrated skin due to wet work. The reason is that protection against dermal absorption of chemicals mainly depends on the condition of the upper very thin layer on the skin (stratum corneum). Fortunately, personal protective equipment such as gloves exists that will prevent or reduce dermal exposure of the hands. It is, however, of immense importance to use the type of gloves suitable for the pesticide in question, and not use disposable gloves more than once. Further, evidence is presented that hand wash following dermal exposure to pesticides significantly reduces absorption.

Different chemical characteristics of pesticides affect their ability to penetrate human skin. This report presents evidence that large molecules (high molecular weight) generally require more time to be absorbed through the skin. Likewise, solubility characteristics of the pesticides will affect penetration rates. This knowledge may be used for establishing mathematic models that can be used to predict dermal penetration characteristics of other chemicals.

This report is aimed at improving the scientific background and the accessibility of knowledge on regulatory measures to prevent or reduce dermal absorption of pesticides. The report is intended to be used as background information by occupational health professionals, labour organizations, and regulatory agencies.