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PubMed1975

Comparative study of methods for the extraction of eleven organophosphorus pesticide residues in rice.

Several extraction methods are compared for the simultaneous analysis of organophosphorus pesticides in unpolished rice. Four stationary phases were used for the subsequent gas-liquid chromatographic (GLC) determination of the selected pesticides. Using 3 different GLC columns, 11 pesticides were completely separated and identified. The efficiency of the cleanup and the sensitivity of the analytical method were evaluated by using powdered unpolished rice samples fortified with the pesticides and also wheat and dried bean samples. Average recoveries ranged from 74.7% for disulfoton to 97.4% for malathion in unpolished rice and from 68.1% for disulfoton to 108.3% for malathion in other crops. The method described is applicable to the analysis of selected organophosphorus pesticide residues in unpolished rice, wheat, buckwheat, and dried beans.

Chromatography, Gas↗
PubMed2002

Predicting pesticide concentrations in river water with a hydrologically calibrated basin-scale runoff model.

Hydrological diffuse pollution models require calibration before they can be used to make accurate long-term predictions for a range of hydrological and meteorological conditions. As such, the applicability of the models to the dispersion of new pesticides is limited due to the lack of calibration data. In this study, the performance of a GIS-based basin-scale runoff model for predicting the concentrations of paddy-farming pesticides in river water was examined when calibrated using hydrological data alone, without optimization based on empirical pesticide concentration data. The prediction accuracy on a daily or hourly scale was somewhat unsatisfactory due to inevitable compromises concerning rice farming schedules. However, the month-averaged pesticide concentrations were satisfactorily accurate; more than 50% of predicted values were between half and twice the observed values, considering the deficiencies of the input data, particularly for pesticide usage, which may include up to 50% error.

Calibration↗
PubMedDate not supplied

Interlaboratory study of a multiresidue gas chromatographic method for determination of organochlorine and pyrethroid pesticides and polychlorobiphenyls in milk, fish, eggs, and beef fat.

An interlaboratory study was conducted to validate a gas chromatographic (GC) method for determination of 21 organochlorine pesticides, 6 pyrethroid pesticides, and 7 polychlorobiphenyl (PCB) congeners in milk, beef fat, fish, and eggs. The method was performed at low contamination levels, which represent relevant contents in food, and is an extension of the European standard (method NF-EN-1528, Parts 1-4). It enlarges the applicable scope of the reference EN method to pyrethroid pesticides and proposes the use of solid-phase extraction (SPE) as a cleanup procedure. Cryogenic extraction was made, and SPE cleanup was performed with 2 successive SPE cartridges: C18 and Florisil. After injection of the purified extract onto a GC column, residues were measured by electron capture detection. Food samples (liquid milk, beef fat, mixed fish, and mixed eggs) were prepared, tested for homogeneity, and sent to 17 laboratories in France. Test portions were spiked with 27 pesticides and 7 PCBs at levels from 26 to 45, 4 to 27, 31 to 67, and 19 to 127 ng/g into milk, eggs, fish, and fat, respectively. Based on results for spiked samples, the relative standard deviation for repeatability ranged from 1.5 to 6.8% in milk, 3 to 39% in eggs, 4.5 to 12.2% in fish, and 7 to 13% in fat. The relative standard deviation for reproducibility ranged from 33 to 50% in milk, 29 to 59% in eggs, 31 to 57% in fish, and 30 to 62% in fat. This method showed acceptable intra- and interlaboratory precision data, as corroborated by HORRAT values at low levels of pesticide and PCB contamination. The statistical evaluation of the results was performed according to the International Organization for Standardization (ISO; ISO 3534 standard) and 5725-2 Guideline.

Algorithms↗
PubMed2001

[Determination of organophosphorus pesticide multi-residues in tea by gas chromatography].

An efficient gas chromatographic method for the determination of 14 organophosphorus pesticide residues in tea by gas chromatography using micro-chemical and solid phase extraction technique has been established. The organophosphorus pesticides were extracted from tea samples with ethyl acetate and mixture of ethyl acetate-hexane(1:1, V/V). The extracts were cleaned up with a column of 3 mL Supelclean Envl-carb by GILSON ASPEC XL. The 14 organophosphorus pesticides were separated from each other through SPB-1701 capillary column(30 m x 0.53 mm i.d. x 1.0 micron) and determined by flame photometric detector. The recoveries ranged 70.8%-120% when the added levels were from 0.100 mg/kg to 1.00 mg/kg, the RSD was 2%-7% and the limits of detection were 0.01 mg/kg-0.08 mg/kg. This method is rapid, sensitive and suitable for the analysis of pesticide residues. It can also be applied to the determination of organophosphorus pesticide multi-residues in other plant samples such as vegetables, fruits and so on.

Chromatography, Gas↗
PubMed2003

Pesticide poisonings reported to the drug and poison information center in Izmir, Turkey.

This study analyzed poisonings caused by pesticides that were reported to Drug and Poison Information Center (DPIC), in Izmir from 1993 to 2001. Patient demographics, type of the pesticide, distribution according to month and year, route and reason for exposure, clinical effects and outcome were analyzed from 25,572 poisoning calls. Pesticide intoxications accounted for 8.8% of the poisonings, with 80.3% insecticides and 19.7% rodenticides. The majority of poisonings ranged from 0 to 6 y (28.2%) and 19-29 y (23.2%). Half the accidental exposures (57.7%) were in the 0-6-y group; the attempted suicide was predominant in the 19-29 y group (39.8%). Most were intoxicated with organophosphates (47.6%); 54.1% did not develop signs and symptoms of toxicity. Fatality due to pesticide poisoning was 0.4%. Preventive education against pesticide poisoning is needed.

Adult↗
PubMed1999

[Application of gas chromatography-mass spectrometry for determination of the organochlorine pesticide residues in ginseng].

A gas chromatographic-electronionization-mass spectrometric method (GC-EIMS) was developed for the determination of organochlorine pesticide residues in Ginseng plants. The Ginseng samples were extracted with acetone, partioned using petroleum ester with sodium chloride saturated aqueous solution and clean-up with concentrated sulfuric acid. The organochlorine pesticide residues were analysed by GC-MS with monitoring selective mass ions. Ten organochlorine pesticides including alpha, beta, gamma and delta isomers of hexachlorocyclohexane (HCH), pp'-DDE, pp'-DDT, op'-DDT, pp'-DDT, pentachloronitrobenzene (Quintozene, PCNB), and hexachlorobenzene(HCB), were determined simultaneously. Targeted pesticide analytes were separated on DB-5 capillary column. The optimum chromatographic conditions and MS parameters were determined. The average recovery rates for those pesticide residues Ginseng were from 76.6% to 90.1% at 0.1 mg/kg of spiked level, except 58.3% for PCNB. The relative standard deviations were 9.3%-15.0%.

Drug Contamination↗
PubMed1992

[Biological activity of bound pesticide residues].

Investigations of bound pesticide residues carried out to date involved the detection of residues in commodities, their identification, determination, bioavailability and possible biological effects. The results obtained in this research and the results of other authors who have shown an increasing concern about the levels, bioavailability and biological effects of bound pesticide residues since the late 1980' are presented in this paper. Based on the results obtained, bound pesticide residues were detected in some commodities ranging from trace amounts to over 50% of the dose level applied. The residue content was influenced by the biochemical structure of the commodity, the compound and its application rate, the length of time from the application to residue analysis as well as on some environmental parameters (primarily temperature and humidity). It was also established that the bioavailability to experimental animals may range from medium to significant provoking adverse biological effects. These effects depended on the compound, its application rate and length of administration. Based on the results obtained so far it was established that bound pesticide residues need to be taken into account when determining maximum residue limits (MRL) as well as when assessing the toxicological risks of pesticide application.

Animal Feed↗
PubMed2003

Screening the retention of thirteen pesticides in a small constructed wetland.

When pesticides are used in arable watersheds, residues are usually found in the recipients. However, small constructed wetlands (CWs) in first and second order streams can reduce the loss of pesticides, since water purification processes are stimulated. This paper presents the results of adding 13 pesticides to a CW in Norway. The relative retention increased between 0 and 67% for the pesticides fluroxypyr, bentazone, dicamba, mecoprop, propiconazole, MCPA, dichlorprop, linuron, fenpropimorph, metalaxyl, metribuzin, metamitron and propachlor. In many cases, the CW reduced the peak concentrations to values regarded as non-toxic for aquatic life, even though the wetland covered less than 0.4% of the watershed surface area, and the average hydraulic load often was above 0.8 m d(-1). Possible retention factors were adsorption to soil particles and organic matter, sedimentation of particles, low or high redox-potential, and biodegradation of nitrogen-rich pesticides. However, the retention processes are complex, and are not fully understood.

Biodegradation, Environmental↗
PubMed2002

[Lipoxygenase-mediated N-demethylation of pesticides in vitro].

OBJECTIVE: In order to explore the pathway of dealkylation of pesticides other than cytochrome P450 monocoxygenases, lipoxygenase (LOX)-mediated demethylation of aminocarb and some other pesticides were measured. METHOD: Formaldehyde generated in the reaction was estimated by Nash reaction to express the rate of demethylation of pesticides mediated by soy lipoxygenase (SLO). RESULTS: N-demethylation of aminocarb mediated by SLO was found to depend on the incubation time, concentration of the enzyme, concentration of aminocarb and hydrogen peroxide. Under optimal conditions, Vmax value of 18 nmol of formaldehyde.min-1.nmol-1 of lipoxygenase was observed. The reaction exhibited Km values of 3.4 mmol/L for aminocarb and 235 mumol/L for hydrogen peroxide. A strong inhibition of the reaction by nordihydroguaiaretic acid, gossypol, and phenidone clearly implicated the lipoxygenase involvement as the protein catalyst. A significant decline in the formaldehyde accumulation in the presence of either reduced glutathione or dithiothreitol suggested generation of a free radical species as an initial oxidation intermediate during the demethylation of aminocarb by SLO. The inhibition of formaldehyde generation by butylated hydroxyanisole(BHT) and butylated hydroxy toluene(BHA) further supported this contention. In addition to aminocarb, seven other pesticides were also found to undergo N-demethylation, albeit at relatively low rates. CONCLUSION: Certain pesticides may oxidatively undergo dealkylation via the lipoxygenase pathway in animals and plants.

Butylated Hydroxyanisole↗
PubMedDate not supplied

[Genotoxic effects of pesticide-treated vegetable extracts using the Allium cepa chromosome aberration and micronucleus tests].

The presence of chemical residues in vegetables and fruit is a source of human exposure to toxic and genotoxic chemicals. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is already known. Several studies have shown that chronic exposure to low levels of pesticides can cause adverse health effects and that many pesticides are mutagenic/carcinogenic. In the present research we monitored concurrently the presence of pesticides and genotoxic compounds extracted from 21 treated vegetables and 8 types of grapes sampled from the markets of a region in Southern Italy. The extracts were analysed for pesticides by gas-chromatography and HPLC, and for genotoxicity with two plant tests in Allium cepa roots: the micronucleus test and the chromosomal aberration test. We found 33 pesticides, some of which are outlawed. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests were sensitive for monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells.

Allium↗
PubMedDate not supplied

Multiresidue analysis of pesticides in vegetables and fruits by gas chromatography/mass spectrometry after gel permeation chromatography and graphitized carbon column cleanup.

A multiresidue method for pesticides that enables quantitative, sequential analysis of a large number of vegetable and fruit samples by gas chromatography/mass spectrometry has been developed. First, 89 important target compounds were selected for monitoring, and then the appropriate internal standards for these pesticides, 14 stable isotopically labeled pesticides (surrogates), were used. The sample was extracted with acetonitrile, and the extract was cleaned up by a salting-out step followed by redissolution in ethyl acetate. Coextractives were removed automatically by gel permeation chromatography with a graphitized carbon column, and then by use of a tandem silica-gel/PSA cartridge column. Recoveries of 82 of the 89 pesticides from fortified spinach, tomato, apple, and strawberry were within a range from 70 to 120%, and the relative standard deviation values of 80 of the 89 pesticides were <5%. The method was applied to 188 commercial vegetable and fruit samples to demonstrate its use in routine analysis.

Chromatography, Gel↗
PubMed2004

Gas chromatographic evaluation of pesticide residue contents in nectarines after non-toxic washing treatments.

Washing with aqueous solutions of citric acid, ethanol, glycerol, hydrogen peroxide, potassium permanganate, sodium metabisulfite, sodium laurylsulfate (SLS), sodium hypochlorite, and urea is evaluated for pesticide residue reduction in nectarines and compared with simple tap water washing. Residues of pesticides commonly utilized in nectarines (chlorpyrifos, fenarimol, iprodione, malathion, methidathion, myclobutanil, parathion and pirimicarb) are extracted with ethyl acetate and anhydrous sodium sulfate, extract is concentred and analyzed by GC with nitrogen-phosphorus detection. The formation of possible toxic by-products (chlorpyrifos oxon, malaoxon, methidaoxon and paraoxon methyl) is studied by GC-MS. No toxic by-products are identified in the extracts of the washed samples for the washing-time and concentrations studied, but high levels of sodium hypochlorite, hydrogen peroxide and potassium permanganate form oxons from the organophosphorus pesticides. Ethanol, glycerol and SLS solutions removed near the 50% of the pesticide residues. The other solutions were not more effective than tap water washing. The amount of pesticide removed by washings is related to its water solubility and octanol-water partition coefficient.

Chromatography, Gas↗
PubMedDate not supplied

Multiresidue determination of pesticides in agricultural products by gas chromatography/mass spectrometry with large volume injection.

A method is described for the rapid determination of pesticide residues in agricultural products. Pesticides were extracted from samples with acetonitrile. To remove pigments and fatty acids, an aliquot of the extract was cleaned up by a minicolumn that was packed both with graphitized carbon black and primary secondary amine. Analysis was performed by gas chromatography/ mass spectrometry with programmable temperature vaporizer-based large volume injection using a liner packed with phenylmethylsilicone chemically bonded silica. The method was evaluated for 114 pesticides by spiking into tomato, spinach, Japanese pear, grape, and brown rice at various concentrations of each pesticide (0.02-0.4 microg/g). The method, which gave good recovery (>60%) for 108 pesticides, is characterized by high cleanup efficiency and short cleanup time, and is useful as a rapid screening analysis.

Buffers↗
PubMed2004

Bioassay of various pesticides by microcalorimetry measuring the metabolic heat of yeast.

Using a microcalorimeter, the heat evolved during incubation of yeast cultures at 30 degrees C was detected in the form of a growth thermogram (metabolic heat-incubation time curve). The correlation between the growth thermograms and the growth curves obtained by colony counting or from the turbidity measurements of the cultures was very good. In this study, the effects of 12 pesticides that are used widely on golf courses on the growth thermograms of yeast were investigated and the inhibitory action of the pesticides on the growth of yeast was quantitatively evaluated using a microcalorimeter (Biothermo Analyzer). The growth thermograms were applied to estimate the microbial activity of yeast in the presence of pesticide and to determine the 50% inhibitory concentration (K) and minimum inhibitory concentration (MIC), which can be regarded as good indexes of the toxic potency of pesticides. It was found that the addition of TPN, captan, thiuram and copper oxide to the yeast cultures clearly induced inhibitory action on the growth of yeast cells. On the other hand, the other 8 pesticides, iprodione, isoprothiorane, chloroneb, pencycuron, metalaxyl, toleclofos-methyl, flutolanil, and mepronil did not affect the growth over the concentration range up to 30 mg/l.

Biological Assay↗
PubMed1992

Pesticide sensitivity registry. What doctors need to know.

Commercially used lawn and home pesticides may cause a variety of symptoms in sensitive individuals. To assist those individuals considered at risk, the Florida Department of Health and Rehabilitative Services (HRS) has developed a process of registering persons sensitive to pesticides, providing they submit certification of their sensitivity by a qualified medical specialist. Pesticide applicators are required by law to inform registered persons of pesticide application to a lawn or exterior foliage on properties contiguous with or adjacent to a registered person at least 24 hours prior to application of the pesticide.

Environmental Exposure↗
PubMedDate not supplied

Host factors and genetic susceptibility: a paradigm of the conundrum of pesticide exposure and cancer associations.

Millions of people are exposed to pesticides in non-trivial ways though their work, their leisure and their home environment. Women and children are understudied populations. The mode and types of pesticides to which women and children are exposed are often different from exposures experienced by men. A relatively small proportion of exposed individuals develop the uncommon cancers that have been associated with exposure to specific pesticides. Host factors, including such variables as gender, age at exposure, previous personal and family history, medical history, and genetic susceptibility have been implicated as explanations. The challenges of designing and implementing studies of pesticide exposure and cancer are examined with a special focus on the complexities of studying the environmental and occupational exposure of women to pesticides of varying toxicity using gender-appropriate methodology.

Environmental Exposure↗
PubMed2005

State-of-the-art measurement of agricultural pesticide exposures.

Accurate exposure estimates are a common goal for risk assessment and epidemiologic research. Current methods for measuring agricultural pesticide exposure have not been fully validated. Epidemiologic studies use questionnaires to estimate exposures, producing job-exposure matrices and exposure algorithms. Biological monitoring can assist in the validation of questionnaire data. Pesticide risk assessments tend to rely on models derived from personal measurements of dermal exposure collected in quasi-experimental studies. Such studies often place constraints on exposure variability. Observational studies of occupational pesticide exposure that incorporate repeated measures are needed to improve the quality of exposure information. Pesticide exposure of family members can occur through spray drift and para-occupational exposures. Residential proximity to pesticide applications has been investigated recently with geographic information system (GIS), and global positioning system (GPS) technology. Biological monitoring can help to characterize exposure pathways in agricultural communities.

Agricultural Workers' Diseases↗
PubMed2005

Detection of pesticide residues in muscles, liver and fat of 3 species of Labeo found in Kalri and Haleji lakes.

The pesticide residues which were detected in fish tissues are DDT, DDE, aldrin, dieldrin and deltamethrin. In total 45 samples were taken out of which 18 were found positive. Out of 18 samples DDT was found in 10 samples in small quantities. DDE was found in 12 samples in higher quantities, aldrin was found in 10 samples and dieldrin was found in 2 samples in small quantities. Deltamethrin was found in 7 samples and malathion in none. Slightly more number of residues were found in Kalri lake samples. However, quantity of pesticides was higher in Haleji lake due to polluted nature of water while number of pesticides was more in Kalri lake water, possibly due to the surrounding adjacent agricultural farms. Higher level of GPT, GOT and ALP was found in samples with higher accumulation of pesticide residues. This possibly indicates a correlation between exposure of pesticide and increased level of the 3 enzymes.

Adipose Tissue↗