Effect of Formulation on Removal of Carbaryl and Chlorothalonil from Apparel Fabrics by Dry Cleaning, Aqueous Extraction, and Vaporization

Abstract

Several methods were examined for efficacy in removal of carbaryl and chlorothalonil contamination from indigo-dyed cotton twill, undyed cotton twill, polyester/cotton broadcloth, and cotton weft knit terry. Fabrics were contaminated with commercial formulations of carbon-14 labeled carbaryl and chlorothalonil, as well as pure carbaryl and chlorothalonil. Vaporization of the pesticides over a 21-day period resulted in a loss of up to 35% of the carbon-14. A hydrocarbon-based dry cleaning solvent was ineffective in removing the pesticides, while a perchloroethylene-based solvent removed ≥76% of the pesticides. More of the pure form of the pesticides was extracted than the formulated form. Repeated extraction with warm water removed 80 to 98% of the pesticides except for pure chlorothalonil of which 40 to 60% was removed. The inert ingredients in the commercial formulation of chlorothalonil appear to increase the efficiency of aqueous extraction.