the use of adjuvants enhances the insecticide efficiency and increases the persistence of insecticides. in this study, the effect of adjuvants on the toxicity of chlorpyrifos and cyhalothrin formulations were investigated under laboratory and field conditions. the comparative toxicity of two chlorpyrifos [(48% emulsifiable concentrate (ec)] formulations (dursban and pyrifos el nasr), two cyhalo...

Hydrolysis of chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate] to TCP (3,5,6-trichloro-2-pyridinol) is an important degradation process influencing the fate of chlorpyrifos in aquatic environments. The effects of water chemistry and suspended colloids (smectites, humic acid, and river sediment) on the hydrolysis of chlorpyrifos were investigated in this study. Chlorpyri...

Chlorpyrifos is an organophosphate insecticide, used to control foliage and soil-borne insect pests on a variety of food and feed crops. In the natural environment, Chlorpyrifos can be degraded  through  several  possible  processes,  including  photodegradation, biodegradation,  and hydrolysis.  In  the  present  work  the  photodegradation  and  environmental  fate  of  Chlorpyrifos  in aqueo...

In vivo transformation of chlorpyrifos to chlorpyrifos oxon is believed to be a prerequisite for this insecticide to display acute toxicity to organisms. We discovered that active chlorine dispersed in water causes the rapid abiotic transformation of chlorpyrifos to chlorpyrifos oxon. The proposed mechanism for the transformation is an electrophilic attack by hypochlorous acid (HOCl) on the thi...

Early life stages of aquatic organisms tend to be more sensitive to various chemical contaminants than later life stages. This research attempted to identify the key biological factors that determined sensitivity differences among life stages of the aquatic insect Chironomous riparius. Specifically, second to fourth instar larvae were exposed in vivo to both low and high waterborne concentratio...

Chlorpyrifos is a pesticide that is metabolically activated to chlorpyrifos oxon (acetylcholinesterase inhibitor) primarily by the cytochrome P450 2B (CYP2B) enzyme subfamily in the liver and brain. We have previously shown that intracerebroventricular pretreatment with a CYP2B inhibitor, C8-Xanthate, can block chlorpyrifos toxicity. Here, we assessed whether delayed introduction of C8-Xanthate...

The objective of this study was to improve the method for determining chlorpyrifos, an organophosphorus insecticide, in various palm oil matrices. Chlorpyrifos was separated from the oil matrices using acetonitrile extraction and then subjected to the solid phase extraction (SPE) clean-up process. A silica-based SPE was used for the clean-up process. Quantification of the extracted chlorpyrifos...

Chlorpyrifos is one of the commonly used organophosphorus insecticides that are implicated in serious environmental and human health problems. To evaluate plant potential for uptake of chlorpyrifos, several plant species of poplar (Populus sp.) and willow (Salix sp.) were investigated. Chlorpyrifos was taken up from nutrient solution by all seven plant species. Significant amounts of chlorpyrif...

Background: Chlorpyrifos is an organophosphate pesticide that elicits broad-spectrum insecticidal activity against a number of important arthropod pests. Determining the insecticides’ toxicity to amphibians can give us a better understanding regarding the role of toxicants in amphibian declines. This information would be beneficial to assess their ecological relevance at environmental con...

An understanding of sorptive processes is key to describing the fate of chlorpyrifos [O,O-diethyl-O-(3, 5, 6-trichloro-2-pyridyl) phosphorothioate] in aquatic environments. The objectives of this study were to evaluate isotherms for adsorption and desorption of chlorpyrifos on colloidal materials and to advance understanding of interaction mechanisms between chlorpyrifos and colloidal materials...