Parathion emulsion

Figure 1. Distribution of parathion emulsion spray applied (1.12 kg/ha) to peach trees (3). A = application level,...

Figure 4. Sunlight degradation products of commercial parathion emulsion formulation in spray droplets, leaf residues, or vapor in the presence of dust or ozone.

Fate. Preliminary investigations directed at adapting the method of Averell and Norris (2) to the analysis of animal tissues indicated that if precautions were taken to avoid emulsions the method could be used satisfactorily. Tissue samples of about 5 grams were most convenient, and the usual reagent and tissue blanks were run simultaneously. Following the administration of an acutely lethal intravenous dose to a dog it was found that parathion could be recovered from the urine, liver, bile, kidney, spleen, and lung. 

Insecticidal parathion is a phosphorothionate ester first licensed for use in 1944. Pure parathion is a yellow liquid that is insoluble in kerosene and water, but stable in contact with water. Among its properties that make parathion convenient to use as an insecticide are stability in contact with neutral and somewhat basic aqueous solutions, low volatility, and toxicity to a wide range of insects. It was applied as an emulsion in water, dust, wettable powder, or aerosol. Even before it was banned for general use, it was not recommended for applications in homes or animal shelters because of its toxicity to mammals. 

The OP parathion and its active metabolite paraoxon were simultaneously determined in plasma and tissues by Abbas and Hayton. Their method involved a simple liquid-liquid extraction with isooctane with subsequent GC-electron capture detection and yielded recoveries from 79-110% for tissues and 91-100% for plasma. Fenitrothion, another OP, was detected in blood samples and tissues by Yoshida et al. using a GC-FPD method. Kojima et al. reported a case of attempted suicide by ingestion of a fenitrothion emulsion fenitrothion and its metabolites were extracted from body fluids by an Extrelut column extraction method and subsequently detected by GC with either FID or FPD. Data were confirmed using GC-MS. No validation data were given. 

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