Removal of pyrazophos from treated fabric using household laundering.

Abstract

The insecticide pyrazophos (O-6-ethoxycarbonyl-5-methylpyrazolo[l,5-a]pyrimidin-2-yl O,O-diethyl phosphorothioate), (AfuEanR), fs currently used for the control of leaf mlners (Phytomza atricornis Meigen) on greenhouse-grown chrysanthemums. The recommended rate of application fs a solution containing 450 mg/L (a.f.) which is sprayed until leaves are thoroughly wet and runoff just begins. During the course of this application, which is frequently carried out under restricted work�8 space, garments and protective clothing can readily come in contact with the spray. Previous workers have studied the effects of various factors �8 the removal of organophosphorus insecticides from contaminated clothing. Easley et al (1981, 1982) have reported on the efficiency of various laundering procedures, detergents, and water temperatures in the removal of methyl parathion from denim fabrics. Laughlin et al (1985) studied the influence of different formulations of methyl parathion on the removal of the insecticide using conventional laundering practices. This note describes a study which was intended to determine the efflciency of household laundering in removing pyrazophos from contamlnated fabrlc. MATERIALSANDMETHODS Cotton/~olyester coverall fabric was eut into lOcm x 20cm strips (200 cm ~) and the edges were machine-stitched to prevent fraying. Four swatches were arranged into layers and placed randomly onto newspaper laid out on the bed of a custom-built cabinet sprayer; the sprayer consisted of an overhead mobile liter container fitted with a nozzle and pressurized by an air pump. The newspaper served to soak up spray around the target fabrics. To simulate drlft ~nd spill situstions, the fabric was sprayed at rates of 48 ml/m ~ and 240 ml/m A respectlvely, uslng a solution of 450 mg pyrazophos per liter of water; these applications were equivalent.to absolute levels of 432 ~g and 2160 ~g of pyrazophos per 200 cmZ-swatch. The fabric was allowed to dry for 8 hours at amblent temperature before being laundered. AI1 treatments were replicated four times. Send reprint requests to H.E. Braun at the above address.