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PubMed2004

In vitro effects of organophosphate pesticides on rat erythrocytes.

In vitro effects of various organophosphate pesticides (dimethoate, chlorpyrifos, ethion and monocrotophos) were studied on hemolysis, K+ leakage and lipid peroxidation in rat erythrocytes. All the four pesticides increased hemolysis and K+ leakage from erythrocytes, that was concentration and time dependent. On the contrary, there was decrease in lipid peroxidation in erythrocyte membrane. Effect of pesticides on lipid peroxidation could be due to pesticide itself abstracting protons or interacting with free radicals rather than polyunsaturated fatty acids (PUFA), thereby protecting the latter against peroxidation.

Animals↗
PubMedDate not supplied

Determination of the residues of eleven organophosphorus insecticides in Job's-tears by gas chromatography with a nitrogen-phosphorus detector.

A simplified method for determining 11 organophosphorus insecticides (dichlorvos, methamidophos, acephate, diazinon, dimethoate, chlorpyrifos, malathion, parathion, quinalphos, methidathion, and ethion) in the Chinese herbal medicine Job's-tears is described. Standards were fortified into Job's-tears (5 g) at 4 levels. The organophosphorus insecticides were extracted with dichloromethane and cleaned up with a mixture of Celite 545-activated carbon (4 + 1). The extracts were analyzed by gas chromatography using a nitrogen-phosphorus detector. Analysis of fortified Job's-tears shows average recoveries ranged from 73.90-98.70%, 86.31-93.15%, 84.92-96.22%, and 83.29-104.23% at 0.05, 0.1, 0.5, and 1.0 mg/kg levels, respectively. The minimum detectable amount ranged from 1.0 x 10(-10) to 5.0 x 10(-10) g, and the limit of quantitation for the method was 0.05 mg/kg. The method is rapid, simple, sensitive, reproducible, and applicable to the determination of these 11 organophosphorus insecticides in Job's-tears.

Chromatography, Gas↗
PubMedDate not supplied

[Agricultural pesticide-related poisonings in Italy: cases reported to the Poison Control Centre of Milan in 2000-2001].

OBJECTIVE: Aim of the present study is to provide a preliminary description of agricultural pesticide-related poisonings in Italy. DESIGN: The study focuses on the cases with at least one sign or symptom due to exposure to agricultural pesticides occurred in 2000-2001 and referred to the Poison control centre of Milan, the Italian centre more frequently consulted nationwide. RESULTS: During the study period, 872 agricultural pesticide-related poisonings were identified. Most of the observed cases occurred in Sicily (n=199), Lombardy (n=100), Apulia (n=99), Veneto (n=75), Emilia-Romagna (n=67) and Campania (n=59). About 86% of the observed cases were unintentional and about 76% of them were men. Children aged 10 or less accounted for about 6% of the total. The poisonings occurred more frequently at home (about 38%) than at workplace (about 24%). The chemical classes of agents more frequently reported were: organophosphates (233 cases), copper and sulphur compounds (140 cases), carbamates (126 cases) and pyrethrins/pyrethroids (102 cases). The top six pesticides associated with poisonings were methomyl (97 cases), dimethoate (59 cases), copper sulfate (58 cases), glyphosate (53 cases), sulphur compounds other than copper sulfate (47 cases), and paraquat dichloride (41 cases). CONCLUSION: The data here presented provide an initial support to identify priorities for prevention in agricultural settings.

Adult↗
PubMed2005

Selectivity lists of pesticides to beneficial arthropods for IPM programs in carrot--first results.

In order to improve IPM programs in carrot, 7 fungicides, 12 herbicides and 9 insecticides commonly used in Belgium were tested for their toxicity towards five beneficial arthropods representative of most important natural enemies encountered in carrot: parasitic wasps - Aphidius rhopalosiphi (De Stefani-Perez) (Hym., Aphidiidae), ladybirds - Adalia bipunctata (L.) (Col., Coccinellidae), hoverfly - Episyrphus balteatus (Dipt.. Syrphidae), rove beetle - Aleochara bilineata (Col., Staphylinidae) and carabid beetle - Bembidion lampros (Col., Carabidae). Initialy, all plant protection products were tested on inert substrate glass plates or sand according to the insect. Products with a corrected mortality (CM) or a parasitism reduction (PR) lower than 30% were kept for the constitution of positive list (green list). The other compounds were further tested on plant for A. rhopalosiphi, A. bipunctata, E. balteatus and soil for B. lampros and A. bilineata. With these extended laboratory tests results, products were listed in toxicity class: green category [CM or PR < or = 30%], yellow category [30% < CM or PR < or = 60%] and orange category [60% < CM or PR < or = 80%]. Products with toxicity higher than 80% on plants or that reduce parasitism more than 80% on soil were put in red category and are not recommended to Integrated Pest Management programs in carrot. Results showed that all fungicides tested were harmless to beneficials except Tebuconazole, which was slightly harmful for A. bipunctata. Herbicides were also harmless for soil beneficials, except Chlorpropham. This product was very toxic on sand towards A. bilineata and must be tested on soil. All soil insecticides tested were very toxic for ground beneficials and considered as non-selective. Their use in IPM is subject to questioning in view of negative impacts on beneficials. Among foliar insecticides, Dimethoate and Deltamethrin are not recommended for IPM because their high toxicity for all beneficials. The other foliar insecticides were more selective; any of them were harmless for all species tested.

Animals↗
PubMed2005

Efficacy of some insecticides against the small red belted clearwing borer, Synanthedon myopaeformis (Borkh.) (Lepidoptera: Sessiidae), in apple orchards in Jordan.

Experiments were carried out in Ash-Shoubak on 10-year old apple trees, Malus domestica cv. Mondial Gala grafted on M26 that were infested with the small red belted clear wing moth. The efficacy of five insecticides was tested against this insect by either spraying or injecting the infested trees. The tested insecticides were; Comodor (imidaclorpid), Chlormezyl (chlorpyrifos & dimethoate), Avaunt (indoxacarb), Thvap (cyromazine) and Actellic (pyrimiphos-methyl). All of these insecticides were applied in 2003 and 2004 except that of Actellic that was applied only in 2004. Data on larval mortality have been observed after 2, 7 and 14 days of insecticides applications. Results showed that spraying or injecting Chlormezyl or Actellic resulted in a significant overall efficacy against the larvae of S. myopaeformis. It was also observed that injecting Comodor improved its overall efficacy against the insect.

Animals↗
PubMed2006

Differential acetylcholinesterase activity in rat cerebrum, cerebellum and hypothalamus.

Acetylcholinesterase (AChE) has been purified from three different regions of rat brain using Sephadex G 200 column. SDS PAGE (6%) showed single band for the purified AChE fractions. Purified and lyophilized AChE from different (NH4)2SO4 precipitated fractions of three brain parts were utilized for in vitro enzyme kinetics using Dimethoate (Dmt) as inhibitor. K(m) values for cerebellum and hypothalamus were almost similar whereas cerebrum showed a different K(m) value compared to other two regions. With the drug Rivastigmine it was found that % G1 and G4 forms of AChE in three different parts of brain are different.

Acetylcholinesterase↗
PubMed2006

[Determination of organophosphorus pesticide residues in tobacco by high performance liquid chromatography-tandem mass spectrometry].

A novel and rapid method based on high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for determination of organophosphorus pesticide residues (OPs) in tobacco. The OPs were extracted from tobacco samples by acetonitrile under ultrasonication. The extractive was determined by high performance liquid chromatography using methanol-water (containing 0.1% ammonium acetate) (95:5, v/v) as mobile phase. The OPs were detected using a tandem mass spectrometer with electrospray ionization in multiple reaction monitoring (MRM) mode. The OPs, such as dimethoate, trichlorfon, chlorpyrifos, methamidophos and acephate could be detected quantitatively within 2.5 min. The linear calibration curves were obtained in the entire range (1-200 microg/L) for all the above pesticides (r > 0.998). The average recoveries in tobacco obtained were ranged from 77% to 104%. The limits of detection were between 1.0 microg/kg and 5.0 microg/kg.

English Abstract↗
PubMed2006

Erythrocyte antioxidant enzymes in toxicological evaluation of commonly used organophosphate pesticides.

Erythrocytes are excellent models for the study of interactions of xenobiotics with biomembranes. Present work is designed to study the in vitro effects of some organophosphates (ethion, chlorpyrifos, dimethoate and monocrotophos) on rat erythrocytes. Treatment of erythrocytes with organophosphates resulted in decreased erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) activity, whereas activities of glutathione-s-transferase (GST) and glutathione reductase (GR) were increased. Reduced Glutathione (GSH) content of RBCs was decreased after treatment with the pesticides. Increased activities of GST and GR were due to induction of natural defense mechanism of erythrocytes against the toxicity of the pesticides. Membrane bound enzymes like acetylcholinesterase (AChE), Na(+)-K(+)-ATPase and Ca(2+)-ATPase were also inhibited. Altered activities of these enzymes along with decreased GSH content indicate increased oxidative stress in erythrocytes after treatment with organophosphates.

Animals↗
PubMedDate not supplied

Postharvest-applied agrochemicals and their residues in fresh fruits and vegetables.

Many agrochemicals are applied postharvest on fruits and vegetables to extend their lives and preserve quality during storage, transport, and marketing. Persistence and distribution of residues on the edible portions of produce have been reported for citrus fruits, pome fruits, stone fruits, mangos, strawberries, bananas, kiwi fruits, avocados, some minor fruit commodities, and bell peppers and tomatoes. Data on the persistance and residues of the fungicides benomyl, biphenyl, sec-butylamine, captan, carbendazim, dicloran, fosetyl-aluminum, guazatine, imazalli, iprodione, metalaxyl, o-phenylphenol, prochloraz, thiabendazole, thiophanate-methyl, triadimeton, and vinclozolin, the fumigants ethylene dibromide, methyl bromide, and sulfur dioxide, the insecticides dimethoate and fenthion, the antiscald compounds diphenylamine and ethoxyquin, and the growth regulators 2,4-D and daminozide are presented and discussed.

Agrochemicals↗
PubMedDate not supplied

Simple analytical method for organophosphorus pesticide residues in milk.

A simple method for determination of organophosphorus pesticide residues at the parts per million level in milk was developed. Pesticide residues were extracted with acetonitrile added to aqueous milk, fat was removed by zinc acetate addition and dichloromethane partition, and analytes were concentrated and analyzed by wide-bore capillary column gas chromatography. Recoveries of 6 pesticides spiked in milk samples at levels of 0.1 and 1.0 micrograms/mL were 82.1-93.8% and 79.7-96.6%, respectively. Triplicate samples spiked with 6 pesticides at 1 microgram/mL were analyzed independently by 3 laboratories. Average recoveries were greater than 80%, and the mean coefficients of variation for the complete study were 2.9% for diazinon, 5.4% for dimethoate, 4.6% for malathion, 4.6% for parathion, 4.9% for EPN, and 6.1% for phosalone.

Animals↗
PubMed1989

[Contact eczema caused by pesticides in East Germany].

19 allergic, occupational contact eczemas and 1 irrative contact dermatitis caused by pesticides from 1985-86 in the GDR are described. The 20 casuistic reports are supplemented with data concerning age, sex, exposure time, patch-test results, occupation site and dermatological details. The following pesticides were determined: maneb, zineb, mancozeb, propineb, thiram, demephion, dimethoate, propachlor, metham-Na, benomyl, chloralhydrate with chloralmethylhalbacetal, carbaryl, dinocap captan, phenyl-Hg-acetate and trichlodinitrobenzene. Each individual case adhered to the recommended test concentration for skin tests. Contact eczemas brought about by the pesticides demephion and trichlordinitrobenzene have not yet to be described. Those working in gardening seem to be particularly prone.

Adult↗
PubMed1989

[Exposure to residues on plant surfaces following the use of plant pesticides in the greenhouse].

Organosphosphorus and carbamate insecticides are quite often used in greenhouses. They represent a group of active principles of toxicological relevance. Initial residues on the surface of cucumber, tomato and ornamental plants, and half-life periods for residue degradation are outlined for carbendazim, dimethoate, fenazox, malathion, methamidophos and pirimiphos-methyl. Residues on plants, concentration in the air, dermal exposition, and inhibition of serum choline esterase activity are shown for methamidophos and aldicarb, respective reentry times being discussed. On harvest and cultivation in greenhouses, dermal exposition as a rule is more relevant than inhalation.

Agricultural Workers' Diseases↗
PubMed1989

[Exposure to residues on plant surfaces following the use of organophosphate insecticides in agricultural apple orchards].

Pesticides based on dimethoate, methamidophos and parathionmethyl are largely used in apple growing centres from the end of May to July. Initial residue concentrations (0.39, 1.4 and 0.4 micrograms.cm-2, respectively) and the degradation of these residues are described together with the relevant half-life periods. They are related to safety margins for residues on leaf surfaces to standardise dermal exposition, respective reentry times being discussed. On the basis of the concentration of active ingredients in the air and of residues on leaf surfaces it is estimated that dermal exposition is predominant on harvest and cultivation in treated apple orchards.

Agricultural Workers' Diseases↗
PubMedDate not supplied

Simplified cleanup and gas chromatographic determination of organophosphorus pesticides in crops.

A simple and efficient cleanup method for gas chromatographic determination of 23 organophosphorus pesticides in crops including onion is described. The sample was extracted with acetone. The extract was purified with coagulating solution, which contained ammonium chloride and phosphoric acid, and then filtered by suction. The filtrate was diluted with NaCl solution and reextracted with benzene. The organic layer was evaporated and injected into a gas chromatograph equipped with a flame photometric detector (FPD) and fused silica capillary columns (0.53 mm id) coated with silicone equivalent to OV-1701, OV-1, and SE-52. Onion extract, which contained FPD interferences, was cleaned up on a disposable silica cartridge. Recoveries of most organophosphorus pesticides from spiked crops: mandarin orange, tomato, spinach, sweet pepper, broccoli, lettuce, and onion at levels of 0.02-0.28 ppm, exceeded 80%, but the water-soluble pesticides dichlorvos and dimethoate gave poor recoveries in all crops; the nonpolar pesticides disulfoton, chlorpyrifos, fenthion, prothiophos, and leptophos were not recovered quantitatively in spinach, sweet pepper, broccoli, and lettuce. IBP, edifenphos, phosmet, and pyridaphenthion were not recovered from onion because of adsorption to the silica cartridge. The detection limits ranged from 1.25 to 17.5 ppb on a crop basis.

Charcoal↗
PubMed1984

[Dissociation of the action of isoprenaline on muscle tension and adenosine-3',5'-monophosphate synthesis in isolated coronary arteries under the effect of diisopropylfluorophosphate].

The basal activity of a particulate adenylate cyclase from bovine coronary arteries was inhibited by low concentrations of diisopropyl-fluorophosphate (DFP), paraoxon and dimethoate. The formation of 14C-labelled cAMP in coronary vessels pulse-labelled with 14C-adenine was inhibited by DFP, too. The stimulating effect of isoprenaline on the cAMP synthesis was completely abolished by DFP both in the cell free system and in pulse-labelled artery preparations. Cholinergic mechanisms are not involved in these actions of DFP because pretreatment with atropine had no influence. DFP both reduced the basal level and completely inhibited the isoprenaline-induced increase of the cyclic AMP content of coronary vessels. In contrast to the biochemical findings there was no observable influence of DFP on the smooth muscle tension or on the relaxation induced by isoprenaline, papaverine and theophylline. The total dissociations of isoprenaline-induced effects on the vascular cAMP system and on smooth muscle tension under the influence of DFP disagree with the opinion according to which beta-adrenergic vascular relaxation is mediated by cAMP.

Adenylyl Cyclases↗
PubMed1983

Applicability of a carbamate insecticide multiresidue method for determining additional types of pesticides in fruits and vegetables.

Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were determined. Analyses were performed by using 3 steps of a multiresidue method for determining N-methylcarbamates in crops: methanol extraction followed by removal of plant co-extractives by solvent partitioning and chromatography with a charcoal-silanized Celite column. Eleven compounds were determined by using a high performance liquid chromatograph equipped with a reverse phase column and a fluorescence detector. Twelve additional compounds were determined by using a gas-liquid chromatograph equipped with a nonpolar packed column and an electron capture or flame photometric detector. Recoveries of 10 pesticides (azinphos ethyl, azinphos methyl, azinphos methyl oxygen analog, carbaryl, carbofuran, naphthalene acetamide, naphthalene acetic acid methyl ester, napropamide, phosalone, and phosalone oxygen analog) and the synergist piperonyl butoxide, which were determined by high performance liquid chromatography, averaged 100% (range 86-117) at the low fortification level and 102% (range 93-115) at the high fortification level. Quantitative recovery of naphthalene acetamide through the method required that an additional portion of eluting solution be passed through the charcoal column. Recoveries of 7 additional pesticides (dimethoate, malathion, methyl parathion, mevinphos, parathion, phorate oxygen analog, and pronamide), which were determined by gas-liquid chromatography (GLC), averaged 108% (range 100-120) at the low fortification level and 107% (range 99-122) at the high fortification level. DDT, diazinon, dieldrin, phorate, and pirimiphos ethyl, which were determined by GLC, were not quantitatively recovered.

Carbamates↗
PubMed1983

Multiresidue method for determination of pesticides in kiwi fruit, apples, and berry fruits.

A rapid multiresidue procedure for fruits, based on methanol extraction, is presented. Water and highly water-soluble co-extractives are removed by partitioning the pesticides into toluene. Carbon-cellulose-Florisil cleanup is performed before gas chromatography on OV-225 with electron capture detection. A wide range of pesticides can be determined to 0.1 mg/kg without concentrating the extract. Gas chromatography of the crude toluene partition using SE-30 and an alkali flame ionization detector provides confirmatory data and allows detection of some carbamates. Dichlorvos, dimethoate, and acephate are determined directly in the methanol extract by flame photometric detection. High recoveries were obtained for 4 organochlorine insecticides, 13 organophosphorus insecticides, 2 synthetic pyrethroids, two N-methyl carbamates, and 10 fungicides. The method is economical of solvents, glassware, and time, and is recommended for routine surveillance of residue levels on fruit.

Chromatography, Gas↗
PubMed1981

Modified Storherr method for determination of organophosphorus pesticides in nonfatty food Total Diet composites.

The method for Storherr et al. for organophosphorus pesticide residues in nonfatty foods has been modified to permit its use in analyzing the composites of nonfatty foods in the Food and Drug Administration Total Diet Program. Modifications were designed to permit the examination by gas-liquid chromatography (GLC) of the larger weight (100 mg) of sample equivalent required by the Total Diet Program. To achieve a limit of quantitation of 2 ppb parathion, the organophosphorus pesticides are determined by GLC equipped with flame photometric detector (P-mode) and/or KCL thermionic detector. Recovery data, ranging from 70 to 133%, are presented for fortification (2-10 ppb) of organophosphorus pesticides in 7 nonfatty food Total Diet composites. The modified Storherr method was successfully tested in an intralaboratory method trial of 2 Total Diet composites (potatoes and legumes) fortified at 5-13 ppb with malathion, parathion, paraoxon, and monocrotophos. In addition, the modified Storherr method was compared to existing FDA Total Diet methodology for the determination of incurred organophosphorus residues. Residue levels found by both methods were similar for malathion (30 ppb), parathion (7 ppb), and diazinon (1 ppb), but only the modified Storherr method was capable of determining about 10 ppb dimethoate and phorate in the cereals and grains composite.

Chromatography, Gas↗