Laundering protocols for chlorpyrifos residue removal from pest control operators' overalls.

摘要

Chlorpyrifos (Dursban PCT, Dursban Micro-Lo and Empire) residue levels in overalls (50% polyester/50% cotton or 100% cotton) after laundering were studied. For Dursban PCT, the polyester/cotton material generally retained a higher amount of chlorpyrifos residue than 100% cotton. Chlorpyrifos residue levels did not significantly vary between cold and hot washes, and between detergents used (Persil concentrate, liquid Drive concentrate, and Drive washing powder). Repeated applications of Dursban PCT, exposure to sunlight before laundering, and reducing the wash time cycle had deleterious effects upon the removal of chlorpyrifos. Cold wash with Persil concentrate was selected as the base line for testing the other formulations. Dursban Micro-Lo resulted in a greater percentage of residual chlorpyrifos than Dursban PCT. Residual chlorpyrifos was significantly lower with Empire. Comparison of the means of trials with fenthion with those for Dursban PCT indicated that the former resulted in a higher amount of residual material after laundering. The degradation of chlorpyrifos to 3,5,6-trichloro-2-pyridinol was studied in the presence of pre-wash agents, including water, chlorine bleach, alkaline detergent, acetic acid (0.05 mol/litre) and sodium hydroxide (0.05 mol/litre). Except for the chlorine bleach, none of the agents were more effective than water alone, with which there was an approximately 30% loss of chlorpyrifos over 144 h. Dursban PCT and fenthion were degraded in the presence of NapiSan (sodium percarbonate) and, at 50 degrees C, degradation over a 24-h period was comparable to that induced by chlorine bleach. Overnight soaking in NapiSan followed by cold wash with Persil reduced the residues of Dursban Micro-Lo to levels comparable with those obtained with pre-soaking with bleach..