ABSTRACT
Organophosphate (OP) pesticides are one group of insecticides commonly used for agricultural purposes. They are also used inside the homes and in yards in smaller quantities to control pests and are currently the most commonly used household insecticides (Kamrin, 1997). These pesticides are also regularly used in others settings such as hospitals and schools with the purpose of controlling for pests (U.S. General Accounting Office [GAO], 1999). They are known to be highly toxic, but their presence in the environment is shorter than that of other types of pesticides (e.g., DDT; Wigle, 2003). Acute poisonings associated with pesticides can occur in spite of extensive control measures. They occur because of misuse, failure of control measures, and/or accidental spills and exposure. These types of incidents are more common than expected. For example, O’Malley (1997) reported that the latest estimates from the World Health Organization (WHO, 1986) indicate that 1 million serious accidental poisonings and 2 million suicide attempts involving pesticides occur each year worldwide. In the United States, it is estimated that there are approximately 10,000 cases per year of poisonings by organophosphate (OP) pesticides (Steenland et al., 1994). In 1990, OP pesticides accounted for 33% of all pesticide poisoning reports in the United States. Diazinon and chlorpyrifos led the list, accounting for more than 50% of the reports (Kamrin, 1997).
