Organophosphate dichlorvos

Among organophosphates dichlorvos (2,2-dichlorovinyl dimethyl phosphate) and pirimiphos methyl (0-[2-(diethylamino)-6-methyl-4-pyr-imidinyl]0,0-dimethylphosphorothioate) are important contaminants for the durum wheat industry. Dichlorvos is one of the most widely used pesticides worldwide in the storage of many products, such as com, rice, and durum wheat, finding widespread use in most European countries... 

Organophosphates Dichlorvos (DDVP) Disulfoton P. californica 10 D. pulex 0.07 Bluegill 700 1... 

Organophosphates (dichlorvos, dimethoat etc.) 63-pm fraction of dust from vacuum cleaner bags GC-MSD (SIM) 1 Walker et al. (1994)... 

Tang J, Liu L, Hu S, Chen Y, Chen J (2009) Improved degradation of organophosphate dichlorvos by Trichoderma atroviride transformants generated by restriction enzyme-mediated integration (REMI). Bioresour Technol 100 480 83... 

JONES, M.W., SOMMERVILLE, c. wooTTEN, R. (1992) Reduced sensitivity of the salmon louse, Lepeophtheirus salmonis, to the organophosphate dichlorvos. Journal of Fish Diseases, 15,197-202. 

Most insecticides, especially the organophosphate group, cause neurotoxicity as their major mode of action. Assessment of the neurotoxicity includes neurochemical endpoints such as cholinesterase (including acetylcholinesterase, which is the major neurotransmitter in vertebrates such as fish, and other enzymes such as butyrylcholinesterase) inhibition and behavioral endpoints such as swimming speed [79]. Studies done in rats show the neurotoxic action of insecticides such as dimethoate, methyl parathion, dichlorvos, ethyl parathion or propoxur after a prolonged exposure [80,81]. 

Metrifonate, an organophosphate compound, is rapidly absorbed after oral administration. After the standard oral dose, peak blood levels are reached in 1-2 hours the half-life is about 1.5 hours. Clearance appears to be through nonenzymatic transformation to dichlorvos, its active metabolite. Metrifonate and dichlorvos are well distributed to the tissues and are completely eliminated in 24-48 hours. 

Dichlorvos is a particularly versatile organophosphate since it can be incorporated as a plasticizer into polyvinyl chloride resin pellets and can be released slowly from the undigestible pellets as they pass through the digestive tract. This allows for a therapeutic concentration against parasites all along the digestive tract. 

Biocides most often found in the indoor environment are chlorinated hydrocarbons like chlordane, DDT, dieldrin, lindane, heptachlor and methoxychlor, pyrethroids like cyfluthrin, cypermethrin, and permethrin, organophosphates like chlorpyrifos, diazinon, dichlorvos, isofenfos, and malathion, carbamates like ben-diocarb, carbaryl and propoxur and chlorophenols like pentachlorophenol (PCP), chlorocresol (4-chloro-3-methylphenol) and o-phenylphenol. Residues formed in house dust may vary in different countries (Butte, 2003), but biocides like chlorpyrifos, DDT, methoxychlor, permethrin, pentchlorophenol and propoxur seem to be the active compounds in biocide formulations even in different continents, as they are found equally in house dust samples form Germany and the USA (Becker et al., 2002 Butte, 2003 Camann, Colt and Zuniga, 2002). Concentrations of biocides in house dust are mostly in the milligram per kilogram range, they seldom exceed a microgram per cubic meter in indoor air. 

Several qualitative and quantitative immunochemical methods and their application to the analysis of environmental samples have been described for OP insecticides, a family that includes widely used pesticides such as azinphos-ethyl/methyl, dichlorvos, fenitrothion or fenthion, malathion, mevinphos, and parathion. Mercader and Montoya202 produced monoclonal antibodies against azinphos-methyl and developed an ELISA that was used for the analysis of water samples from different sources, reaching detectability levels near 0.05 pg I. Watanabe et al.203 reported the production of polyclonal antibodies and ELISA procedures to analyze fenitrothion in river, tap, and mineral water (LOD = 0.3 pg L ). Banks et al.204 produced polyclonal antibodies against dichlorvos, an organophosphate insecticide used for stored grain, which also cross-reacts with fenitrothion. Nishi et al.205 reported the first immunoassay for malathion. Residues of this insecticide have... 

The OP compounds are difficult to generalize with respect to their physical properties. They have moderate-to-considerable water solubility. Some organophosphate insecticides are water soluble, e.g., oxydemeton-methyl, azodrin, phosdrin, trichlorfon, and phosph-amidon. They also have moderate-to-considerable vapor pressures, generally in the range 10"3-10-5 mm Hg. Some organophosphate insecticides such as naled and dichlorvos are very volatile. This combination of physical and chemical properties makes the entire class of insecticides biodegradable and nonpersistent. 

Examples of organophosphates include the insecticides malathion, parathion, diazinon, fenthion, azinphos methyl, terbufos, dichlorvos, and chlorpyr-ifos the nerve gases soman, sarin, tabun, and VX the ophthalmic agent echothiophate the anthelmintic trichlorfon tricresyl phosphate-containing... 

Chemical and Physical Properties Trichlorfon is an organophosphate compound, which has an empirical formula of C4HgCl304P and a molecular weight of 257.44. It is a racemic mixture of two isomers. Trichlorfon is a pale clear, white or yellow crystalline powder, melting point 75-84°C, boiling point 100°C, vapor pressure 7.8mmHg at 20°C, and is stable at normal temperatures and pressure. At higher temperatures and pH less than 5.5, trichlorfon decomposes to form dichlorvos (0,0-dimethyl-0-(2,2-dichlorovinyl) phosphate, DDVP). It is readily soluble in chloroform and methylene chloride, and less soluble in water, benzene, and diethyl ether. 

Other organophosphate compounds commonly used on chicken premises include dichlorvos, malathion, and parathion. Birds poisoned by these... 

See also Aflatoxin Algae Ammonia Asbestos Benzene Hexachloride, Mixed Isomers Brodifacoum Carbamate Pesticides Carbon Monoxide Castor Bean Copper Coumarins DDT (Dichlorodiphenyltrichloroethane) DEET (Diethyltoluamide) Dichlorvos Dieldrin Ethylene Glycol Hydrogen Sulfide Lead Malathion Methane Molybdenum Mushrooms, Coprine Mushrooms, Cyclopeptide Mycotoxins Nitrites Oleander Organochlorine Insecticides Organophosphates Paraquat Parathion Pyrethrins/Pyrethroids Selenium Sodium Strychnine Sulfur Dioxide Thallium Warfarin. 

Ivermectin Organophosphate Haloxon Dichlorvos Mites, horse bots Horse bots Oral paste Oral powder (horses) Oral gel (foals) ... 

Organophosphate Dimpylate (diazinon) Dichlorvos Fenitrothion Fenthion Phosmet (dogs) Fleas, ticks Solution (spot on) collars aerosol spray liquid concentrate (sponge on)... 

Delayed neurotoxicity results from degeneration of the axons followed by demyelination (14,15,23). Clinical manifestation includes sensory disturbances, ataxia, weakness, muscle twitching and, in severe cases, complete flaccid paralysis ( 15). A fair number of organophosphate compounds are capable of inducing delayed neurotoxicity. Of the 250 organophosphates (not all pesticides) tested for delayed neurotoxicity in chickens, 47% (117 chemicals) showed positive responses (23). Notable examples of pesticides which possess this neurotoxicity are leptophos, EPN, merphos, dichlorvos, and... 

Pesticides as a class contain 2 widely quoted examples of ambiguity between mutagenic activity and carcinogenicity. Dichlorvos (2,2-dichlorovinyl dimethyl phosphate), an organophosphate insecticide, and ziram (bis(dimethyldithio-carbamate)zinc), a dithiocarbamate fungicide, are confirmed bacterial mutagens [13]. 

C. Metrifonate Metrifonate is an organophosphate prodrug that is converted in the body to the cholinesterase inhibitor dichlorvos. The active metabolite acts solely against Schistosoma haematobium (the cause of bilharziasis). Toxic effects occur from excess cholinergic stimulation. 

C. Cholinesterase Inhibitors The carbamates (eg, aldicarb, carbaryl) and organophosphates (eg, dichlorvos, malathion, parathion) are effective insecticides with short environmental half-lives. The cholinesterase inhibitors are inexpensive and are heavily used in agriculture. 

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