Protective clothing is the principal defense of millions of farm workers and pesticide mixers/applicators against skin contamination by pesticides. Unfortunately, few data are available in the public domain to permit the identification of appropriate protective items for specific categories and types of pesticides and pesticide formulations. The U.S. Environmental Protection Agency (EPA) has therefore sponsored an effort to produce, assemble, and critically evaluate data on the effectiveness of protective clothing for agricultural uses. This paper describes (1) efforts to develop a rapid screening method for determining the compatibility of various glove materials with selected pesticides and (2) comparative analyses of collection media for use with the ASTM Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids and Gases (F 739-85) permeation cell in tests of low-volatility, low-water-solubility active ingredients in pesticide formulations.
Two methods for the rapid screening of protective glove-pesticide formulation compatibilities were tested. Results obtained with a draft ASTM Test Method for Evaluating Protective Clothing Materials for Resistance to Degradation by Liquid Chemicals suggest that inappropriate formulation-glove combinations may be identified by their excessive weight increase after 1-h exposure.
Permeation testing to determine breakthrough times and measure the permeation of formulation components using the ASTM F 739-85 cell and selected gloves and pesticide formulations is a major focus of this program. However, the collection medium to be used in this test when evaluating low-volatility, low-water-solubility pesticides poses a particular program. Various media (water, aqueous surfactant solutions, aqueous alcohol solutions, and solid phase collection materials) were tested using actual pesticide formulations spiked with 14C-labeled active ingredients. A solid silicone rubber material was identified as the most efficient material for collection of parathion and ethion. It has now been used with several protective glove materials and two concentrated pesticide formulations.