Fabrics were contaminated daily with methyl parathion for up to five days, laundered, and residues before and after laundering determined. Two fabrics (100% cotton and 50/50% cotton/polyester) of two finishes (unfinished and fluorocarbon soil-repellent) were studied with one-half the specimens laundered daily following contamination and the other half laundered only on the last day following daily contamination.
Gas chromatographic analysis showed that methyl parathion soiling was additive over the five-day period at each additional contamination. The soil-repellent finish was effective through two launderings in limiting sorption of pesticide. In specimens laundered daily, post-laundering residues were similar across each of the five days. Differences in laundered fabric attributable to the fiber content of the specimen and to the functional finish were observed.
Soiling increased across the five days with no laundering such that the washing process was not as effective in removal of the methyl parathion residues. When specimens were contaminated repeatedly and lundered only once, the analysis of wash water showed sizable contaminate; however, when the specimens were laundered daily, proportionately less contamination was evident.