The acceptability of a chlorine bleach pretreatment for removal of chlorpyrifos residues from cotton and polyester/cotton fabrics

A chlorine bleach pretreatment is effective for the removal of dilute chlorpyrifos from both cotton and polyester/cotton as shown in earlier research. This study determined to what extent repeated bleach soak/wash cycles degrade and/or change the color of cotton and polyester/cotton fabrics, and whether pesticide applicators will accept strength loss and/or color change in work clothing. Two 100% cotton and two 65/35 polyester/cotton fabrics, both dyed and undyed, were subjected to 25 chlorine bleach soak/wash cycles using the laundry protocol previously found effective for the removal of dilute chlorpyrifos residues. After designated laundry intervals, samples were removed and specimens cut for breaking strength tests and visual and instrumental evaluation of colorfastness. Data were also collected at pesticide applicator conferences, seminars, and workshops. A brief questionnaire was completed by pesticide applicators after viewing an educational poster presenting the bleach soak/wash protocol as the most effective method to clean work clothing contaminated with dilute chlorpyrifos, but indicating that colorfastness and strength of 100% cotton are sacrificed. Responses indicated that reducing pesticide residue to very low levels is more important to applicators than colorfastness or durability.