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Bulletin of Environmental Contamination... Aug 2007
Topics: Biodegradation, Environmental; Insecticides; Molecular Structure; Organothiophosphorus Compounds; Soil Microbiology; Soil Pollutants; Stereoisomerism
PubMed: 17510729
DOI: 10.1007/s00128-007-9099-5 -
Journal of Pharmaceutical and... May 2007A simple and rapid method was developed for measuring 10 organophosphorus pesticides (acephate, methidathion, dichlorvos, fenthion, EPN, diazinon, phenthoate, malathion,... (Comparative Study)
Comparative Study
A simple and rapid method was developed for measuring 10 organophosphorus pesticides (acephate, methidathion, dichlorvos, fenthion, EPN, diazinon, phenthoate, malathion, fenitrothion, and cyanophos) in the serum of acute poisoning patients by LC/MS. Following deproteinization by acetonitrile, an aliquot of the biological sample was injected into a C(18) column using 10mM ammonium formate-methanol as the mobile phase. Extraction recoveries were satisfactory and ranged between 60.0 and 108.1% in serum. The limits of detection (LODs) in serum ranged from 0.125 to 1 microg/ml, and the limits of quantitation (LOQs) ranged from 0.25 to 1.25 microg/ml. An excellent linearity was observed for these LOQs up to 8 microg/ml. Intra- and interassay precision and accuracy were satisfactory for most of the pesticides analyzed. In terms of temperature stability, of all the organophosphorus compounds analyzed, dichlorvos and malathion exhibited the most rapid degradations over 24h at room temperature. Methidathion and diazinon remained relatively stable at all temperatures during the entire 4-week testing period. The present method was successfully applied to one actual case of acute poisoning. In conclusion, this method is simple, accurate, and useful for the determination of organophosphorus pesticides and should benefit both clinical and forensic toxicology.
Topics: Chromatography, Liquid; Drug Stability; Forensic Toxicology; Freezing; Humans; Male; Mass Spectrometry; Middle Aged; Molecular Structure; Organophosphate Poisoning; Organophosphorus Compounds; Pesticides; Reproducibility of Results; Sensitivity and Specificity; Suicide, Attempted; Time Factors
PubMed: 17337150
DOI: 10.1016/j.jpba.2007.01.036 -
Chemosphere Dec 2006Many investigations on protists indicate that they play an important role in agricultural soils. We have tested the effects of three organophosphate (OP) pesticides,...
Many investigations on protists indicate that they play an important role in agricultural soils. We have tested the effects of three organophosphate (OP) pesticides, basudin, cidial, and fenix, on the soil ciliate Colpoda inflata, and examined its viability, fission rate, ability to excyst and extrude macronuclear chromatin into cytoplasm. Exposure to these OPs caused a dose-dependent effect on cell viability, and significantly reduced the mean fission rate at a concentration of 1/10(5) v/v. After exposure of resting cysts to 1/10(5) v/v or 1/10(6) v/v concentrations of basudin or cidial, the number of excysted cells was significantly lower than that of the controls. Conversely, exposure to a 1/10(5) v/v fenix concentration did not affect excystment and exposure to 1/10(6) v/v was found to promote excystment. Moreover, exposure to these OPs (1/10(4) v/v or 1/10(5) v/v) interferred with the ability to extrude macronuclear chromatin. The median lethal concentration in 60 min for each OPs tested was at least a hundred times lower than the doses recommended by the manufacturer. Finally, as the inhibition of cholinesterase (ChE) activity is the first target of OPs, the presence of ChE activity was checked in C. inflata. Three ChE activities were found, hydrolyzing the substrates acetyl-beta-methyl thiocholine iodide, propionyl thiocholine iodide and butyryl thiocholine iodide, that appeared to be very low and not inhibited by OP-exposure.
Topics: Animals; Cell Survival; Cholinesterase Inhibitors; Cholinesterases; Ciliophora; Dose-Response Relationship, Drug; Organophosphorus Compounds; Organothiophosphorus Compounds; Pesticides; Soil Microbiology
PubMed: 17228426
DOI: 10.1016/j.chemosphere.2006.04.081 -
Ecotoxicology (London, England) Oct 2006The present study was aimed at applying condition factor (CF), brain acetylcholinesterase (AChE) and gill histology as biomarkers for detecting possible exposure/effect...
The present study was aimed at applying condition factor (CF), brain acetylcholinesterase (AChE) and gill histology as biomarkers for detecting possible exposure/effect induced by pesticides in fish residing rice field associated waterbodies in Sri Lanka. Biomarkers of an indigenous fish, Rasbora caverii collected from five sampling sites including canals near rice fields, a river and a reservoir (the reference site) were evaluated at four sampling stages covering pesticide application periods during rice cultivation season in 2004. Results indicated that CF of the fish did not show significant alterations regardless of the sampling sites or sampling stages. Site specific differences in AChE activities of the fish were not evident either prior to application of pesticides or at 7 days after Paraquat application to the rice fields. Two days after the application of a mixture of Fenthion and Phenthoate to the rice fields, AChE activity of the fish collected from canals near rice fields was significantly depressed (65-75%) compared to the fish in the reference site. The activities remain depressed to 50-56% even at 65 days after the insecticides application. Laboratory studies showed that prior exposure of R. caverii to Paraquat (2 microg l(-1), 7 days) enhanced the extent of inhibition of brain AChE activity induced by Fenthion (3 microg l(-1)) or a mixture of Fenthion (3 microg l(-1)) and Phenthoate (5 microg l(-1)). Gills of fish collected from canals near rice fields exhibited abnormal multiple divisions at the tips of some secondary lamellae in addition to hyperplasia, hypertrophy and club shaped deformities. Results indicate that application of pesticides in rice culture could manifest a threat to native fish populations residing rice field associated waterbodies. The response of brain AChE and histological changes in the gills of R. caverii allowed differentiating sampling sites after insecticide applications to the rice fields. Hence, R. caverii may be considered as a surrogate species in ecotoxicological risk evaluation of agrochemicals in the region.
Topics: Acetylcholinesterase; Agriculture; Animals; Biomarkers; Brain; Environmental Monitoring; Fishes; Gills; Pesticides; Sri Lanka; Water Pollutants, Chemical
PubMed: 17024560
DOI: 10.1007/s10646-006-0101-5 -
Legal Medicine (Tokyo, Japan) May 2006We investigated the stability of 14 organophosphorus insecticides: dichlorvos, fenitrothion, cyanophos, malathion, phenthoate, methidathion, dimethoate, thiometon,...
We investigated the stability of 14 organophosphorus insecticides: dichlorvos, fenitrothion, cyanophos, malathion, phenthoate, methidathion, dimethoate, thiometon, isoxathion, diazinon, trichlorfon, EPN, acephate and sulprofos, in fresh blood. The organophosphorus compounds, except for sulprofos, decomposed over time at 37 degrees C, with varying decomposition speed for each compound. Methyl phosphate types (dichlorvos) decomposed most rapidly, followed by methyl thiophosphate types (fenitrothion and cyanophos) and methyl dithiophosphate types (methidathion, dimethoate and thiometon). Methyl thiophosphate types decomposed faster than ethyl thiophosphate types (isoxathion and diazinon). Of the five methyl dithiophosphate type insecticides (malathion, phenthoate, methidathion, dimethoate and thiometon), the compounds with a carboxylic ester bond (malathion and phenthoate) decomposed faster than the others. Compounds left standing at 37 degrees C decomposed faster than those left standing at 4 degrees C. Temperature has a great effect on the decomposition of organophosphorus insecticides in blood. However, the order of the decomposition speeds of each compound was approximately the same at different temperatures. In cases of suspected organophosphate poisoning, it should be considered that the blood concentration of the compound might decrease during the postmortem interval.
Topics: Chromatography, High Pressure Liquid; Drug Stability; Forensic Medicine; Humans; Insecticides; Organophosphorus Compounds; Specimen Handling; Temperature
PubMed: 16517205
DOI: 10.1016/j.legalmed.2005.12.003 -
Journal of Chromatography. A Apr 2005In the present work, a novel sample pre-treatment technique for the determination of trace concentrations of some insecticide compounds in aqueous samples has been...
In the present work, a novel sample pre-treatment technique for the determination of trace concentrations of some insecticide compounds in aqueous samples has been developed and applied to the determination of the selected analytes in environmental water samples. The extraction procedure is based on coupling polypropylene hollow fiber liquid phase microextraction (HF-LPME) with gas chromatography by flame thermionic detection (GC-FTD). For the development of the method, seven organophosphorous insecticides (dichlorvos, mevinphos-cis, ethoprophos, chlorpyrifos methyl, phenthoate, methidathion and carbofenothion) and one carbamate (carbofuran) were considered as target analytes. Several factors that influence the efficiency of HF-LPME were investigated and optimized including agitation, organic solvent, sample volume, exposure time, salt additives and pH. The optimized methodology exhibited good linearity with correlation coefficient = 0.990. The analytical precision for the target analytes ranged from 4.3 to 11.1 for within-day variation and 4.6 to 12.0% for between-day variation. The detection limits for all analytes were found in the range from 0.001 to 0.072 microg/L, well below the limits established by the EC Drinking Water Directive (EEC 80/778). Relative recoveries obtained by the proposed method from drinking and river water samples ranged from 80 to 104% with coefficient of variations ranging from 4.5 to 10.7%. The present methodology is easy, rapid, sensitive and requires small sample volumes to screen environmental water samples for insecticide residues.
Topics: Chemical Fractionation; Hydrogen-Ion Concentration; Insecticides; Microchemistry; Reproducibility of Results; Water Pollutants, Chemical
PubMed: 15881459
DOI: 10.1016/j.chroma.2004.11.076 -
Comparative Biochemistry and... Dec 2004To examine the functional effects of cholinergic modulation compounds in oyster hearts and to explore their possible use in monitoring intoxication with...
To examine the functional effects of cholinergic modulation compounds in oyster hearts and to explore their possible use in monitoring intoxication with acetylcholine-esterase (AChE) inhibitors such as organophosphates, tests were performed with in situ oyster heart preparations. The endogenous cholinergic agonist acetylcholine (ACh), AChE-resistant synthetic agonist carbachol, and the reversible carbamate type of AChE inhibitor physostigmine, all potently depressed spontaneous cardiac contractility. The depression was reversed by extensive washout, or prevented by muscarinic cholinergic antagonist atropine. The irreversible organophosphate type AChE inhibitor parathion or its active metabolite paraoxon at concentrations up to 100 microM failed to depress cardiac contractility. While other reversible AChE inhibitors such neostigmine and pyridostigmine also depressed the contractility, organophosphate AChE inhibitors malathion, diazinon, or phenthoate did not. Despite the differential effect in depressing cardiac function between the reversible and irreversible inhibitors, both of these inhibitors effectively inhibited cardiac AChE activity. The results suggest that the activation of muscarinic cholinergic receptors is coupled to inhibitory cardiac modulation, and organophosphate AChE inhibitors may inhibit only an AChE isozyme located at sites that are not important for control of cardiac activity in oysters.
Topics: Acetylcholine; Animals; Carbachol; Cholinergic Agonists; Cholinesterase Inhibitors; Heart; Heart Rate; In Vitro Techniques; Insecticides; Myocardial Contraction; Ostreidae; Paraoxon; Parathion; Physostigmine
PubMed: 15683842
DOI: 10.1016/j.cca.2004.12.009 -
Bulletin of Environmental Contamination... Nov 2004
Topics: Agriculture; Climate; Environmental Pollutants; Insecticides; Organothiophosphorus Compounds
PubMed: 15669725
DOI: 10.1007/s00128-004-0501-2 -
Journal of Environmental Sciences... 2004Adsorption of phenthoate and acetochlor onto kaolin, montmorillonite, bentonite clays and respective organoclays prepared by the exchange of quaternary ammonium as... (Comparative Study)
Comparative Study
Adsorption of phenthoate and acetochlor onto kaolin, montmorillonite, bentonite clays and respective organoclays prepared by the exchange of quaternary ammonium as tetradecyltrimethyl ammonium bromide(TTAB), dodecyltrimethylammonium bromide (DTAB), and cetylpyridinium chloride (CPC) were studied. The adsorption equilibrium data points were fitted to Freundlich isotherm equations. The adsorption of phenthoate and acetochlor were significantly enhanced by surfactant treatment of the clays. The amount of both pesticides adsorbed per unit mass of organoclay followed the order of TTA-kaolin < TTA-montmorillonite < TTA-bentonite, which is inconsistent with the organic carbon content of the clays. The removal efficiency of organomontmorillonite to treat acetochlor is in the order of CP (C16)-montmorillonite > TTA (C14)-montmorillonite > DTA (C12)-montmorillonite. Phenthoate is adsorbed to greater extent than acetochlor by each adsorbent, which may be due to the higher hydrophobicity of phenthoate, indicating considerable hydrophobic interaction between adsorbent/adsorbate systems.
Topics: Adsorption; Aluminum Silicates; Bromides; China; Chromatography, High Pressure Liquid; Organothiophosphorus Compounds; Pesticides; Quaternary Ammonium Compounds; Surface-Active Agents; Toluidines; Water Pollution, Chemical
PubMed: 15559802
DOI: No ID Found -
Pest Management Science Sep 2004A 110-fold acetamiprid-resistant Plutella xylostella (L) strain was established after four selection experiments (in five generations) on a 9.5-fold resistant colony in...
A 110-fold acetamiprid-resistant Plutella xylostella (L) strain was established after four selection experiments (in five generations) on a 9.5-fold resistant colony in the laboratory. The resistant strain did not show cross-resistance to chlorfluazuron or Bacillus thuringiensis subsp kurstaki Berliner, but displayed low resistance to cartap and phenthoate.
Topics: Animals; Bacillus thuringiensis; Insecticide Resistance; Insecticides; Larva; Moths; Neonicotinoids; Organothiophosphorus Compounds; Phenylurea Compounds; Pyridines; Thiocarbamates
PubMed: 15382497
DOI: 10.1002/ps.933