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PubMed1998

Multiresidue analysis of pesticides using new laminar extraction disks and liquid chromatography and application to the French priority list.

The national French lists of priority pesticides to be monitored in drinking and/or surface water contain various pesticides with a wide range of physico-chemical properties and can be modified on a regional scale with the addition of other pesticides, depending on local agricultural usage. A multiresidue extraction method is presented using new disk formats engineered for high throughput that are particularly well adapted to the extraction of compounds from high volumes of dirty samples. However, because of the occurrence of very polar and very apolar compounds in the lists, two procedures are required for the extraction step. Divinylbenzene disks were used to extract the more polar compounds, as well as the moderately polar or acidic ones. For apolar pesticides, a C18 silica disk was used, and 10% methanol was added to the water sample before percolation in order to avoid adsorption on the flasks and connecting tubes. Since 1 l of surface water is extracted in less than 5 min without previous filtration using these new laminar disks, the percolation time is no longer a limiting factor in the analysis scheme of surface water samples containing suspended matter. The sample volume can be easily increased in order to reach lower detection limits, provided that the extraction conditions have been optimized in order to minimize the amount of co-extracted and interfering substances. A considerable decrease in the effect of the humic and fulvic substances was achieved using divinylbenzene disks, which allows the samples to be handled at pH 6, for the polar pesticides. Moreover, the necessary addition of 10% methanol in the samples for the extraction of the apolar ones also considerably decreases the amount of co-extracted analytes. The time of the whole sample preparation sequence, i.e., conditioning of the disks, sample extraction, sample clean-up and desorption, is achieved within 10 min for six simultaneous samples. Detection limits in the range 0.01-0.05 microgram l-1 are easily obtained for most pesticides contained in the national lists from 1 l of real surface water samples. The two procedures described in this work allow the handling of any compounds having a water-octanol constant, log Kow, in the range 1-6.

Chromatography, Liquid↗

PubMed1998

Simultaneous pulsed flame photometric and mass spectrometric detection for enhanced pesticide analysis capabilities.

Analysis of pesticides by simultaneous pulsed flame photometric detection (PFPD) and mass spectrometric (MS) detection was performed with column-effluent splitting between these two detectors. The resulting PFPD chromatograms were always much simpler due to the PFPD selectively and were further characterized by better sensitivity than that of MS. Accordingly, the PFPD chromatogram served as a marker for the exact elution time of the suspected pesticide. At this exact elution time, the resulting mass spectra were examined of unique high-mass peaks and a precise background subtraction was performed for improved library identification. If no definite identification was achieved, reconstructed mass chromatograms were performed, inspected for suspected major ions and confirmed with the PFPD chromatogram. A sequential search was then performed with the NIST library. The presence of P or S atoms was introduced into the search algorithm and two of the major suspected fragment mass peaks were included with an estimate of their minimum relative abundance. Under these conditions, the library search provided the correct pesticide identification, at a considerably lower concentration than achievable with standard GC-MC analysis. If only information on a single ion was available, such as with very pronounced matrix interferences, or with single-ion monitoring MS analysis, the NIST library sequential search was operated with this single-on information and PFPD provided information on both P and S (the majority of organophosphorus pesticides contain both P and S). The incorporation of one major ion and two heteroatoms' (P and S) information enabled an effective library identification, at an even further reduced pesticide concentration. The simultaneous PFPD-MS analysis approach is demonstrated and discussed with several examples of authentic pesticides in vegetable and spices. The merits of this method are analyzed and discussed with an emphasis on the unique suitability of PFPD for combination with MS.

Chromatography, Gas↗

PubMed1997

Alternative measures of pesticide use.

One kilogram of a pesticide is not necessarily equal to a kilogram of a different pesticide. This issue can be significant. Whether it is depends on the use to which pesticide-use data are put. While kilograms of pesticide is the most common way of measuring agricultural chemical use, the type of analysis will generally define what measure of chemical use is best. Quantifying the risk from the exposure to pesticides, for example, typically requires weighing usage or residues by acute or chronic health and environmental toxicity coefficients and subsequently estimating human or environmental exposure to such hazards. The interferences one draws concerning pesticide use can vary substantially depending on the measure considered.

Agriculture↗

PubMed1982

Pesticide photoproducts: generation and significance.

As with the parent pesticide, the significance of a pesticide photoproduct depends on its concentration in a given environmental compartment, its toxicity, and exposure of the organism or ecosystem of interest. This requires an understanding of the production and environmental chemistry of each photoproduct as well as its toxicity. While these data are generally available for the parent pesticide, they are rarely determined in detail for the photoproducts. Although the environmental photochemistry of each pesticide is different, some generalizations can be made. Photochemical oxidations, reductions, hydrolytic reactions, and isomerizations often generate products identical to those of metabolic and nonbiological transformations. The chemistry and environmental stability of each individual photoproduct can be substantially different from those of the original pesticide and other products. With several notable exceptions, however, photoproducts are generally less stable to environmental forces and less toxic than the parent pesticide, at least to the target organism. A most significant exception is the P = S to P = O conversion in the organophosphorus insecticides. This sunlight promoted reaction is important in treated fields and has been implicated as a cause of injury to farmworkers.

Air Pollutants↗

PubMedDate not supplied

New monitoring system for ninety pesticides and related compounds in river water by solid-phase extraction with determination by gas chromatography/mass spectrometry.

A new monitoring system was established for the determination of 90 pesticides and 10 pesticide degradation products in river water. The pesticides consisted of 18 fungicides, 30 insecticides, and 42 herbicides. The pesticides were extracted with a solid-phase, styrene-divinylbenzene copolymer, eluted with acetone, hexane, and ethyl acetate, and determined by gas chromatography/mass spectrometry. Overall recoveries ranged from 72 to 118%. The limits of detection were 0.01-0.1 microgram/L. This system determines most of the pesticides used in Japan and was successfully applied to practical monitoring of water polluted with pesticides and related compounds.

Environmental Monitoring↗

PubMedDate not supplied

Dietary exposure of Thais to pesticides during 1989-1996.

To monitor the exposure of the Thai to pesticide residues in foods, the intake of pesticides based on the total diet approach has been studied in Thailand continually since 1989. Food items were chosen and their proportions of daily consumption were calculated from the national food consumption survey conducted by the Department of Health in 1986. Seventy-seven items of food including drinking water were classified into 12 groups according to their sources of contamination and the analytical methods used. Shopping lists and standard procedures for collecting samples and cooking were developed. Twelve food composites from each of the 4 regions were analyzed for nearly 100 pesticides. All analyses used multiresidue analytical methods, and the total daily dietary intakes of pesticide residues were estimated from the average amount of food consumed by Thais. Among 24 pesticides found in the 8 year study, DDT, dimethoate, methamidophos, and parathion methyl were found every year. However, dietary intakes of all pesticides were far below the established acceptable daily intake. In 1999, the study methodology was redesigned to accommodate the new national food consumption survey data.

Carbamates↗

PubMedDate not supplied

Use of buffering and other means to improve results of problematic pesticides in a fast and easy method for residue analysis of fruits and vegetables.

A modification that entails the use of buffering during extraction was made to further improve results for certain problematic pesticides (e.g., folpet, dichlofluanid, chlorothalonil, and pymetrozine) in a simple, fast, and inexpensive method for the determination of pesticides in produce. The method, known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods, now involves the extraction of the sample with acetonitrile (MeCN) containing 1% acetic acid (HAc) and simultaneous liquid-liquid partitioning formed by adding anhydrous MgSO4 plus sodium acetate (NaAc). The extraction method is carried out by shaking a centrifuge tube which contains 1 mL of 1% HAc in MeCN plus 0.4 g anhydrous MgSO4 and 0.1 g anhydrous NaAc per g sample. The tube is then centrifuged, and a portion of the extract is transferred to a tube containing 50 mg primary secondary amine sorbent plus 150 mg anhydrous MgSO4/mL of extract. After a mixing and centrifugation step, the extract is transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry. Independent of the original sample pH, the use of buffering during the extraction yields pH <4 in the MeCN extract and >5 in the water phase, which increases recoveries of both acid- and base-sensitive pesticides. The method was evaluated for 32 diverse pesticides in different matrixes, and typical percent recoveries were 95 +/- 10, even for some problematic pesticides. Optional solvent exchange to toluene prior to GC/MS analysis was also evaluated, showing equally good results with the benefit of lower detection limits, but at the cost of more time, material, labor, and expense.

Beverages↗

PubMedDate not supplied

Stability of pesticides on solid-phase extraction disks after incubation at various temperatures and for various time intervals: interlaboratory study.

An interlaboratory study was conducted at 8 locations to assess the stability of pesticides on solid-phase extraction (SPE) disks after incubation at various temperatures and for various time intervals. Deionized water fortified with selected pesticides was extracted by using 2 types of SPE filtration disks (Empore C18 and Speedisk C18XF), and after extraction, the disks were incubated at 3 temperatures (25, 40, and 55 degrees C) and for 2 time intervals (4 and 14 days). Deionized water was fortified with atrazine, carbofuran, and chlorpyrifos by all participating laboratories. In addition, some of the laboratories included 2 of the following pesticides: metolachlor, metribuzin, simazine, chlorothalonil, and malathion. Concurrently, fortified water samples were extracted with the incubated samples by using each disk type at 4 and 14 days. Pesticides had equivalent or greater stability on > or = 1 of the C18 disk types, compared with storage in water. The lowest recoveries of carbofuran (6%) and chlorpyrifos (7%) were obtained at 55 degrees C after storage for 14 days in incubated water. At 55 degrees C after 14 days, the lowest recovery for atrazine was 65% obtained by using Empore disks. Pesticide-specific losses occurred on the C18 disks in this study, underlining the importance of temperature and time interval when water is extracted at remote field locations and the SPE disks containing the extracted pesticides are transported or shipped to a laboratory for elution and analysis.

Calibration↗

PubMed2006

[Analysis of pesticide multiresidues in rice by gas chromatography-mass spectrometry coupled with solid phase extraction].

A new analytical method was developed to simultaneously determine multiple pesticide residues in rice including organophosphorus, organochlorine, carbamate and pyrethroid. First, the solvents for pesticide extraction were selected for optimization. Eight solvents were screened to find that the extraction efficiency with dichloromethane was the best. Second, clean-up was performed by solid phase extraction using a Florisil cartridge. Various mixtures of hexane and acetone were tested to show that the mixture of hexane-acetone (4:1, v/v) had the best performance. The clean-up helped the sample purification significantly. The prepared sample was analyzed using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The pesticides were identified with retention time and selected ions and their relative abundances, and they were quantified based on extract of spiking standards in a blank sample. The limits of detection (LODs) were evaluated on the values of the lower concentration fortified sample under the signal-to-noise ratio of 3:1. The recoveries and relative standard deviations (RSDs) were checked by adding pesticide standard solution at two levels to untreated samples, and the triplicate analysis of the samples were carried out for each spiked level. The LODs were at microg/kg level. The average recoveries of most pesticides were from 75% to 120 %. The RSDs were less than 10.4% (n = 3). These results indicated that this method is simple, rapid, sensitive for the simultaneous determination requirements of multiple pesticide residues in rice.

Food Contamination↗

PubMed1999

Allergic contact and photoallergic contact dermatitis to plant and pesticide allergens.

BACKGROUND: The panel of patch test allergens used for the evaluation of patients with suspected photoallergy typically does not include plant and pesticide allergens. The prevalence of allergic contact dermatitis and photoallergic contact dermatitis to plant and pesticide allergens was determined for this subgroup of patients. OBSERVATION: Positive reactions were detected in 12 of 26 patients who were tested with our photoallergen series: 5 with allergic contact dermatitis, 5 with photoallergic contact dermatitis, and 2 with both. Four of the 12 patients had positive patch and photo-patch test reactions to plant allergens, pesticide allergens, or both. The positive patch test reactions were to the plants Taraxacum officinale (dandelion) and Tanacetum vulgare (tansy) and to the pesticides folpet and captafol. Positive photo-patch test reactions were to the pesticides folpet and captan. The histories of the patients suggested that 2 or 3 of the 4 patients had clinically relevant reactions. In the other 8 patients, positive reactions to the patch and photo-patch tests included fragrances, sunscreens, and antibacterial agents. CONCLUSION: Plant and pesticide allergens should be included in the patch and photo-patch test series used for the evaluation of patients with suspected photoallergy.

Adult↗

PubMed2000

Pesticide exposures in children with non-Hodgkin lymphoma.

BACKGROUND: The association between pesticide exposure and non-Hodgkin lymphoma (NHL) in adults has been the subject of numerous case-control and cohort studies. However, to the authors' knowledge, data regarding pesticide exposures in children diagnosed with NHL have been lacking. METHODS: The Children's Cancer Group conducted a study comparing 268 children who developed NHL or leukemia with bulk disease with a group of matched, randomly selected regional population controls. The telephone interviews of both the case and control mothers included selected questions regarding occupational and home exposures to pesticides around the time of the index pregnancy and exposure of the child. RESULTS: A significant association was found between risk of NHL and increased frequency of reported pesticide use in the home (odds ratio [OR] = 7.3 for use most days; trend P = 0.05), professional exterminations within the home (OR = 3.0; P = 0.002), and postnatal exposure (OR = 2.4; P = 0.001). Elevated risks were found for T-cell and B-cell lymphomas; for lymphoblastic, large cell, and Burkitt morphologies; and in both young (age < 6 years) and older children. There was an increased risk of NHL with occupational exposure to pesticides (OR = 1.7) that was not significant overall, but that was significant for Burkitt lymphoma (OR = 9.6; P < 0.05). CONCLUSIONS: The results of the current study provide further evidence linking pesticide exposure to the risk of NHL, but the authors were unable to implicate any specific agent.

Adolescent↗

PubMed2001

Organophosphate pesticide residues in urine of farmworkers and their children in Fresno County, California.

BACKGROUND: Childhood cancer, notably leukemia, brain cancer, non-Hodgkin's lymphoma, soft tissue sarcoma, and Hodgkin's disease, has been associated with pesticide exposure, often with greater relative risks than among exposed adults, suggesting greater susceptibility in children. These differences in risk may be due to developmental factors or differences in pesticide exposure. METHODS: A feasibility study was conducted to determine levels of pesticide metabolites in urine of adults (n = 18) and children (n = 9) in Fresno County, California, an intensely agricultural county in the Central San Joaquin Valley. Spot urine samples were obtained and analyzed for six metabolites of organophosphate (OP) pesticides using gas chromatography with flame photometric detection methods. The metabolites of OP pesticides included DMP, DEP, DMTP, DMDTP, DETP, and DEDTP. RESULTS: Levels were generally low for both adults and children for most metabolites tested. Frequencies of detection ranged from 0 to 37%, with mean levels ranging from non-detectable to 13.22 ppb. However, levels of several metabolites were higher in children than in adults. The most frequently detected metabolite, DMP, was found among 44% of the children and 33% of the adults. DMTP was detected among 33% of the children and 28% of the adults. CONCLUSIONS: These results are difficult to interpret given the sampling variation associated with the small sample size. Nevertheless, because OP pesticides have been associated with increased cancer risk in animal and human studies, these results indicate a need to closely monitor children's exposure to environmental chemicals.

Agriculture↗

PubMed2002

Compliance with required pesticide-specific protective equipment use.

BACKGROUND: This study measured compliance with pesticide-specific protective gear use requirements practiced by farmers applying pesticides to field crops. MATERIALS AND METHODS: Two hundred and twenty randomly selected dairy farmers were interviewed 1 week after pesticide application to determine use of personal protective equipment while applying at least 1 of 15 possible restricted use pesticides (response rate = 82.4%). RESULTS: Among the three most common pesticides used (dicamba, atrazine, and cyanazine), the proportions of farmers fully complying with gear use requirements were 8.8, 8.6, and 2.5%, respectively. For those same pesticides, the proportions (and 95% CI) using none of the required gear were 56.9% (47.3-66.5%), 38.6% (27.2-50.0%), and 47.5%(32.0-63.0%), respectively. CONCLUSIONS: Both full and partial compliance with required personal protective equipment was low for each of the 15 chemicals applied by the applicators in this sample.

Adult↗

PubMed2003

Occupational asthma symptoms and respiratory function among aerial pesticide applicators.

BACKGROUND: Pesticide exposure has been suggested as one causal factor for the rise in asthma prevalence. The goal of this investigation was to determine the effect of pesticide exposure on respiratory symptoms and lung function in workers with occupational exposure to pesticides. METHODS: A prospective, case-controlled study was conducted among pesticide aviators (AV) and community controls (Con). In Phase I, subjects completed an asthma survey and baseline spirometry. In Phase II, subjects reported symptoms, lung function monitoring, and pesticide exposure during two, 14-day periods. RESULTS: Phase I-Self-reported asthma and symptoms were similar among AV (n = 135) and Con (n = 118) with 4-6% prevalence reported but with higher rates among smokers. Baseline lung function was similar; although, a higher proportion of AV had forced expiratory volume in one second (FEV(1)) <80% predicted (8% vs. 2%, P = 0.02). Phase II-Self-reported symptoms were similar with 80% of AV (n = 50) and 73% of Con (n = 49) reporting no symptoms. Only 4% of AV and 6% of controls reported increased symptoms from baseline to spray season. Serial lung function did not differ between group and mean diurnal variation in peak expiratory flow improved in both groups between sampling times (AV 18% vs. 14%; Con 19% vs. 16%, P < 0.001). CONCLUSIONS: This study suggests that among workers with occupational pesticide exposure, asthma symptoms and lung function are similar to those of controls with only community-based exposure.

Adult↗

PubMed2004

Health symptoms and exposure to organophosphate pesticides in farmworkers.

BACKGROUND: Few studies have examined the relationship between reported health symptoms and exposure to organophosphate (OP) pesticides. METHODS: Fisher's exact test was used to assess the relationship between self-reported health symptoms and indicators of exposure to OP pesticides in 211 farmworkers in Eastern Washington. RESULTS: The health symptoms most commonly reported included headaches (50%), burning eyes (39%), pain in muscles, joints, or bones (35%), a rash or itchy skin (25%), and blurred vision (23%). Exposure to pesticides was prevalent. The proportion of detectable samples of various pesticide residues in house and vehicle dust was weakly associated with reporting certain health symptoms, particularly burning eyes and shortness of breath. No significant associations were found between reporting health symptoms and the proportion of detectable urinary pesticide metabolites. CONCLUSIONS: Certain self-reported health symptoms in farmworkers may be associated with indicators of exposure to pesticides. Longitudinal studies with more precise health symptom data are needed to explore this relationship further.

Adolescent↗

PubMed2006

Pesticide exposure and risk for Parkinson's disease.

OBJECTIVE: Chronic, low-dose exposure to pesticides is suspected to increase the risk for Parkinson's disease (PD), but data are inconclusive. METHODS: We prospectively examined whether individuals exposed to pesticides have higher risk for PD than those not exposed. The study population comprised participants in the Cancer Prevention Study II Nutrition Cohort, a longitudinal investigation of US men and women initiated in 1992 by the American Cancer Society. Follow-up surveys were conducted in 1997, 1999, and 2001. The 143,325 individuals who returned the 2001 survey and did not have a diagnosis or symptoms of PD at baseline (1992) were included in the analyses. RESULTS: Exposure to pesticides was reported by 7,864 participants (5.7%), including 1,956 farmers, ranchers, or fishermen. Individuals exposed to pesticides had a 70% higher incidence of PD than those not exposed (adjusted relative risk, 1.7; 95% confidence interval, 1.2-2.3; p = 0.002). The relative risk for pesticide exposure was similar in farmers and nonfarmers. No relation was found between risk for PD and exposure to asbestos, chemical/acids/solvents, coal or stone dust, or eight other occupational exposures. INTERPRETATION: These data support the hypothesis that exposure to pesticides may increase risk for PD. Future studies should seek to identify the specific chemicals responsible for this association.

Aged↗

PubMed2004

Highly sensitive analysis of multiple pesticides in foods combining solid-phase microextraction, capillary electrophoresis-mass spectrometry, and chemometrics.

A highly sensitive procedure to detect multiple pesticides at trace levels in foods is presented. Initially a comparative study between capillary electrophoresis (CE)-UV and CE-mass spectrometry (MS) is carried out analyzing five pesticides not studied up to now (pyrimethanil, pyrifenox, cyprodinil, cyromazine, and pirimicarb). The comparison between CE-UV and CE-MS is established in terms of separation efficiency, speed of analysis, reproducibility, and sensitivity. A good separation of these compounds is achieved by both techniques using a volatile aqueous buffer containing 0.3 M ammonium acetate/acetic acid at pH 4. Time analysis reproducibility is studied for the same day (n = 5) and three different days (n = 15), showing no significant differences between CE-UV and CE-MS. The study on peak areas reproducibility shows a slightly worse reproducibility for CE-MS compared with CE-UV. The best limit of detection (LOD) that can be achieved for these pesticides using CE-UV was 0.6 microg/mL. CE-MS provides LODs one order of magnitude better than CE-UV. Chemometrics are used to optimize the multiple parameters that play a role in solid-phase microextraction (SPME) and CE-MS analysis (e.g., extraction and desorption times, nebulizer pressure, dry gas flow, dry gas temperature, percentage of organic solvent and acid in the sheath liquid, etc.). The combined use of chemometrics and SPME-CE-MS clearly improves the LODs that can be achieved allowing the detection of pesticides at concentrations down to 15 ng/mL. The usefulness of this approach is demonstrated detecting multiple pesticides in different food samples as grapes and orange juice in a single run. The concentrations detected are below the maximum residue limits (MRLs) permitted for these pesticides in foods corroborating the value of our approach. This work demonstrates, to our knowledge for the first time, the good possibilities of the combined use of SPME-CE-MS and chemometrics.

Absorption↗

PubMed2004

Non-Hodgkin's lymphoma among asthmatics exposed to pesticides.

We conducted a pooled analysis of population-based case-control studies in Iowa, Minnesota and Nebraska to investigate whether asthma modifies risk of non-Hodgkin's lymphoma (NHL) associated with pesticide exposures. Cases (n = 872) diagnosed with NHL from 1980 to 1986 and frequency-matched controls (n = 2,381) randomly selected from the same geographic areas as the cases were included. Information on use of pesticides and history of asthma was based on interviews. Unconditional logistic regression was used to calculate ORs, adjusted for age, state and vital status. Of all subjects, 177 (45 cases, 132 controls) reported having been told by their doctor that they had asthma. Subjects with an asthma history had a nonsignificantly lower risk of NHL than nonasthmatics (OR = 0.6, 95% CI 0.3-1.4), and there was no main effect of pesticide exposure (OR = 1.0, 95% CI 0.8-1.2). However, asthmatics tended to have larger ORs associated with exposure to pesticides than nonasthmatics. The OR among asthmatics was 1.8 (95% CI 1.1-3.2) for ever-use of crop insecticides, 2.7 (95% CI 1.0-7.2) for chlordane, 2.4 (95% CI 1.0-5.7) for lindane and 3.7 (95% CI 1.3-10.9) for fonofos. Among nonasthmatics, ORs were 1.1 (0.9-1.3), 1.5 (1.1-2.2), 1.3 (0.97-1.8) and 1.6 (1.0-2.4), respectively. Although there is limited power for assessing interaction, our results suggest that the risk of NHL among asthmatics with pesticide exposure may be higher than among nonasthmatics with pesticide exposure.

Aged↗