The Toxicity of Fenitrothion and Permethrin

Fenitrothion: An organophosphorus insecticide, fenitrothion (O,O-dimethyl O-4-nitro-m-tolyl phosphorothioate; CAS No. 122-14-5), which is a yellow-brown liquid with an unpleasant odor at room temperature, was introduced in 1959 by both Sumitomo Chemical Company and Bayer Leverkusen, and later by American Cyanamid Company (Hayes, 1982; Hayes and Laws, 1990; Worthing and Walker, 1987). Organophosphorus insecticides began with the massive development of agriculture and agribusiness after World War II. At that time, parathion, one of the famous organophosphorus insecticides, was used in large quantities for preventing rice-stem borer worldwide. However, because of the high acute toxicity, parathion was thought to be an extremely hazardous substance. In man, an oral dose of 3-5 mg/kg is usually fatal. The following case report additionally came across the high toxicity and persistence in humans (Clifford and Nies, 1989). A 25-year-old worker in a pesticide-formulating plant was contaminated after accidentally spilling a 76% parathion solution on his groin and scrotal areas. Although he showered and changed clothes immediately, the resulting nausea and diarrhea made him consult a doctor two days later. The worker placed the parathionsaturated uniform in a plastic bag to be burned. But the contaminated clothing was laundered, and then was used in succession by a second worker, who wore it until he had complaints similar to the first worker. The coveralls were again laundered and used by still a third intoxicated worker. Totally, three workers suffered from toxic reaction to parathion. This case shows the toxic nature of parathion and its persistence on clothing even after successive laundering. Moreover, Etzel et al. (1987) reported that 49 persons in Sierra Leone were acutely poisoned by parathion in May and June 1986, 14 of whom later died. The casecontrol study of the employed 21 cases and 22 household controls was undertaken to explore which factors were associated with the development of the symptoms such as excess salivation, excess tearing, increased urination, diarrhea, convulsions, and loss of consciousness. Each case and control were questioned about foods and beverages that had been consumed during the 4 hours before becoming ill (for cases) or on the day of a case’s illness (for controls). The odds ratio of cases (12.7; 95% confidence interval (CI), 2.4-83.8) for taking bread was significantly increased, suggesting that cases were more likely than controls to have eaten bread within the 4 hours before becoming ill. In addition, when stratified by age, the odds ratio was far higher in children under 18 years (odds ratio, 21.7; 95% CI, 2.4-264.6) than adults (odds ratio, 2.3; 95% CI, 0.02-195.9). This may be due to the higher consumption of parathion based on body weight or higher susceptibility to the