In November 1994 methyl parathion (MP), a restricted agricultural pesticide, was discovered to have been illegally sprayed within hundreds of residences in Lorain County, Ohio. Surface levels and air concentrations of MP revealed detectable levels of the pesticide 3 years after spraying. Because of the high toxicity of MP (lethal dose to 50% of rats tested [LD50] = 15 mg/kg) and long half-life ...

A flow injection amperometric biosensor for the determination of organophosphate nerve agents was developed. The biosensor incorporated an immobilized enzyme reactor that contains the enzyme organophosphorus hydrolase covalently immobilized on activated aminopropyl controlled pore glass beads and an electrochemical flow-through detector containing carbon paste working electrode, a silver/silver...

As the single most important pest of field corn, Zea mays L., throughout most of the Corn Belt, the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), has undergone repeated selection for resistance to a variety of insecticides that persist widely among Nebraska populations. In this study, we used 11 microsatellite markers to genotype two populations with...

The separation of 9 organophosphates (monocrotophos, quinalphos, triazophos, parathion-methyl, isofenphos-methyl, temephos, parathion, phoxim-ethyl, and chlorpyrifos) by high-performance thin-layer chromatography (HPTLC) with automated multiple development was studied. The HPTLC method was developed and validated for analysis of residues of phoxim-ethyl and chlorpyrifos in tea. The sample was e...

Biological parameters were followed in soils from a cotton farm (Tatui) where the recommended pesticides have been used for years, and from an experimental field (São Paulo) which was subdivided in two areas: one received the recommended pesticides and the other was maintained untreated. The soil bioactivities monitored from 1995 to 1998, after different pesticide applications, were: basal and ...

The Agency for Toxic Substances and Disease Registry analyzed concurrently collected data on environmental methyl parathion (MP) and urinary p-nitrophenol (PNP) at the request of the U.S. Environmental Protection Agency (U.S. EPA). The purpose of the analysis was to assess whether individuals' age or level of residential MP contamination might predict their urinary PNP level. Unlicensed pestici...

An evaluation of toxic effects of three organophosphorus pesticides viz. monocrotophos, methyl parathion and dimethoate given orally daily for 90 days was done in terms of enzymatic changes in plasma and liver of female albino rats. A significant decrease was observed in the level of esterases in plasma with all the three pesticides. The activity of acid and alkaline phosphatases and aminotrans...

Polyvinyl chloride (PVC) can be used to develop reaction beaker which acts as electrochemical cell for the measurement of OP pesticides. Being chemically inert, corrosion resistant, and easy in molding to various shapes and size, PVC can be used for the immobilization of enzyme. Organophosphorus hydrolase was immobilized covalently onto the chemically activated inner surface of PVC beaker by us...

An amperometric biosensor based on the immobilization of organophosphorus hydrolase (OPH) onto screen-printed carbon electrodes is shown useful for the rapid, sensitive, and low-cost detection of organophosphate (OP) nerve agents. The sensor relies upon the sensitive and rapid anodic detection of the enzymatically generated p-nitrophenol product at the OPH/Nafion layer immobilized onto the thic...