Abstract
The aims of this study were to recommend gloves (lined, unsupported Solvex nitrile, Viton, or Silver Shield laminate) to protect against malathion skin exposure, and to investigate how the carrier (water, hexane, or m-xylene) modified the permeation of the malathion of two commercial emulsion concentrate formulations. An I-PTC 600 American Society for Testing and Materials-type permeation cell at 30°C allowed hexane collection of malathion, with samples taken every 10 minutes for gas chromatography/mass spectrometry analysis. Malathion did not permeate Silver Shield or Viton up to 8 hours at 30°C whether it was pure or formulated. Of all the formulation and mixture experiments, pure malathion had the shortest breakthrough time (tb), shortest lag time (t1), and highest steady-state permeation rate (Ps) through nitrile. Malathion did not permeate within 8 hours when the formulation of low alkylbenzene content was diluted to the same malathion concentration in water as malathion/m-xylene was with hexane. In contrast, the formulation of high alkylbenzene content at this aqueous dilution allowed malathion permeation, with a tb of 4 to 5 hours and a long t1. Viton and Silver Shield gloves are recommended for handling technical/pure-grade malathion and malathion emulsifiable concentrate formulations. Nitrile gloves should be replaced every 60 minutes when handling these two formulations because of the malathion tb of 1 hour, but they will not protect against pure/technical malathion. Nitrile can be used for at least 4 hours to protect against diluted formulations and diluted pure/technical malathion.
