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Permeation mechanisms of pesticides through materials.
Que Hee SS
Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, R01-OH-002951, 1995 Apr; :1-22
Permeation studies of formulations with pesticidal active ingredients that included chlorpyrifos, 2,4-dichlorophenoxyacetic acid or 2,4-D (ester and salt fonDs), endosulfan, malathion, and methomyl proceeded in an ASTM-type permeation cell with liquid solvent collection, and analysis of permeated inert components and pesticides by gas chromatography/mass spectrometry (GC/MS). Challenge conditions were with formulations and diluted formulations in aqueous and organic solutions to mimick field exposure conditions of worker handling in a formulary and field spraying, respectively. GC/MS of the formulations enabled the compositions of the volatile inert components and the pesticides to be determined for reconstitution studies. The gloves recommended for full 8 h/working day protection of workers against all these formulations are Silver Shield and Viton. Nitrile glove change times to prevent pesticide breakthrough were specified for each formulation type. The liquid pesticide malathion permeated nitrile the most whereas the solid pesticides required the inert components to permeate. The inert components moderated the permeative properties of pure malathion. In addition the alkylbenzene components of formulations did not permeate together but rather permeated sequentially, breakthrough times increasing with increasing molecular weight. This caused investigation of the pure alkylbenzene isomers of molecular weight 106 and 120 for their permeation behavior for the first time. Water solubility, log Kow (where Kow is the octanoVwater partition coefficient), viscosity, and chromatographic parameters showed the best correlations to the permeation kinetic parameters (breakthrough time, steady state permeation rate, the lag time, and diffusion coefficients). This led to the development of different theories of permeation, the most promising being a chromatographic model and a solvochromic partitioning model based on log K(subscript)heptane. The generality of the models needs to be tested further.
Worker-health; Pesticide-industry; Pesticides; Pesticides-and-agricultural-chemicals; Protective-clothing; Gloves; Protective-clothing; Protective-equipment; Personal-protective-equipment
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National Institute for Occupational Safety and Health
University of California, School of Public Health, Department of Environmental Health Sciences, 10333 Le Conte Avenue, Los Angeles, CA 90024-1772
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division