Laundry parameters as factors in lowering methyl parathion residue in cotton/polyester fabrics.

Cotton/polyester fabrics were contaminated with a 1.25% solution of methyl parathion (MeP) emulsifiable concentrate formulation, then laboratory laundered. The laundering variables were detergent type, concentration, water volume, and mechanical agitation. Specimens were unfinished (UN) and soil repellent finished (SR) fabrics. Heavy duty liquid and phosphate-built powdered detergents were equally effective when used in combination with a prewash product. A negative linear relationship between detergent concentration and MeP residue remaining after laundering was established. An interaction between detergent concentration and fabric finish was observed. Soil repellent finished fabrics required detergent concentrations above the recommended amount for more efficient soil removal. A negative linear relationship between water volume and after-laundering residue was observed. Water volume played a more significant role in pesticide removal than agitation during laundering.