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PubMed2004

Effect of pesticide exposure on acetylcholinesterase activity in subsistence farmers from Campeche, Mexico.

The authors surveyed agricultural production methods and pesticide use among subsistence farmers (campesinos) in 4 rural communities of Campeche, Mexico. Self-reports of symptoms of poisoning resulting from occupational pesticide exposure were elicited by questionnaire (N = 121), and acetylcholinesterase (AChE) activity during insecticide use was evaluated from blood samples (N = 127). In individuals from 2 of the 4 communities, AChE activity was significantly lower (p < 0.05) than the mean of activity determined for individuals in a reference group. Results of this study show that erythrocyte AChE inhibition provides a good biomarker of exposure to organophosphate pesticides in field studies with human populations. Carbamates, particularly carbofuran, seem to be more associated with exuberant and diversified symptomatology of pesticide exposure than organophosphates. Studies in field communities where both carbamates and organophosphates are suspected to exist should include blood AChE determinations, symptomatology surveys, and socioeconomic questionnaires. The authors recommend that the Mexican National Health Ministry authorities specify additional provisions regarding the use of protective equipment and the adoption of other safety practices during field work, increase information campaigns about the risks of pesticide use and the value of safety practices, and increase programs of medical monitoring and assistance for rural communities dealing with pesticides.

Acetylcholinesterase↗
PubMed2003

[Simultaneous determination of pesticide residues in fruits and vegetables by GC/MS (SCAN mode) and HPLC].

A method was developed for simultaneous determination of pesticide residues in fruits and vegetables. Residues were extracted from samples with acetonitrile, followed by a salting-out step and a partitioning step with n-hexane at the same time. Co-extractives were removed with ENVI-Carb/LC-NH2 mini-column cleanup. Analysis was performed by GC/MS (SCAN mode) and HPLC. Of the 139 pesticides spiked at 0.1 or 0.5 microgram/g into 6 fruits and vegetables (spinach, tomato, apple, radish, cabbage and carrot), recoveries of 117 pesticides were between 70 and 120%. This method is appropriate for determining these pesticides and for screening several other pesticides for which the recoveries were < or = 70% or > or = 120% (imazalil, etc.). The limits of detection for most pesticides in this method were equal to or lower than those of the bulletin method in Japan.

Chromatography, High Pressure Liquid↗
PubMed2003

[Simultaneous determination of N-methylcarbamate and urea pesticides in agricultural products by LC/MS].

A simultaneous determination method of 7 N-methylcarbamate and 7 urea pesticides in agricultural products by liquid chromatography/mass spectrometry (LC/MS) has been developed. Under reversed-phase liquid chromatographic conditions, 14 pesticides were analyzed using electrospray ionization (ESI) with simultaneous acquisition of positive ions and negative ions. Fourteen pesticides were extracted with acetone, 10% NaCl solution was added, and the pesticides were re-extracted with dichloromethane. The extract was concentrated under reduced pressure, and dissolved in methanol. The detection limits of 14 pesticides ranged from 0.0012 to 0.0056 microgram/g. The recoveries of pesticides were from 36.5 to 112.5% [RSD (n = 3) ranged from 0.5 to 48.1%] for 4 agricultural products.

Carbamates↗
PubMed2004

[Analysis of pesticides including chlorine in welsh onions and mushrooms using gas chromatograph with an atomic emission detector (GC-AED)].

An analytical method for the determination of 32 kinds of pesticide residues in onions, Welsh onions and mushrooms using gas chromatograph with an atomic emission detector (GC-AED) was developed. The pesticides were extracted with acetone-n-hexane (2:3) mixture. The crude extract was partitioned between 5% sodium chloride and ethyl acetate-n-hexane (1:4) mixture. The extract was passed through a Florisil mini-column for cleanup with 10 mL of acetone-n-hexane (1:9) mixture. Although the sensitivity of GC-AED was inferior to that of GC-ECD, GC-AED has a superior element-selectivity. Therefore pesticide residues in foods could be analyzed more exactly by using GC-AED. Thirty-two pesticides including chlorine in onion, Welsh onion and shiitake mushroom were detected without interference. Recoveries of these pesticides from samples determined by GC-AED were 64-114%, except for a few pesticides.

Chromatography, Gas↗
PubMed2004

[Investigation of pesticide residues in foods distributed in Kitakyushu City].

We investigated 160 kinds of pesticide residues in 715 samples of 116 kinds of foods distributed in Kitakyushu city. Sixty kinds of pesticides were detected in 55 kinds of foods (204 samples) in the range of 0.002-22 mg/kg. Five kinds of pesticides in 7 samples violated the residue standards and the indication of "unused". The detection ratios of unregulated pesticide in domestic and imported foods were 27.8 and 33.0%, respectively. Iprodione, dicofol, diethofencarb, procymidone and chlorfenapyr (for domestic food) and total bromine, benomyl, chlorpyrifos, dicofol, fenvalerate, cypermethrin and dimethoate (for imported food) showed relatively high detection ratios. Chinese cabbage, garland chrysanthemum, tomatoes and green teas (domestic) and broccoli, bananas, grapefruit, lemons, oranges, frozen edamame and frozen kidney beans (imported) showed high relative pesticide detection ratios. Residual pesticides were detected with relatively high frequency in imported fruits, imported frozen foods and imported processed foods.

Chromatography, Gel↗
PubMed2005

[Multiresidue method for determination of pesticides in fruits and vegetables by GC/MS (SCAN) and LC/MS (SIM)].

A rapid multiresidue method has been developed for determination of many pesticides in fruits and vegetables using GC/MS and LC/MS. The method of analysis was the same as that reported by Kakimoto et al. in 2003 except for the use of LC/MS. Good recoveries in the range of 70-120% were obtained for 70 (32 by GC/MS, 38 by LC/MS) of 113 pesticides spiked at 0.1 microg/g into fruits and vegetables. For screening purposes, the method could be appiled to 82 pesticides. Considering the report by Kakimoto et al. in 2004, 177 pesticides were suitable for screening by this method. The limits of detection were 0.001-0.015 microg/g (by GC/MS) and < 0.001-0.010 microg/g (by LC/MS). The calibration curves were linear for most pesticides, with correlation coefficients of 0.976-1.000 (by GC/MS) and 0.968-1.000 (by LC/MS). The values obtained for fruits and vegetables naturally contaminated with pesticides by this method were nearly equal to those by the official method.

Chromatography, High Pressure Liquid↗
PubMed1994

Potential parental exposure to pesticides and limb reduction defects.

OBJECTIVES: The goal of the study was to examine the effects of the potential pesticide exposure of parents on the risk of limb reduction defects in their offspring. METHODS: A case-referent study was conducted utilizing New York State Congenital Malformation Register data. Persons with limb reduction defects and referents were compared in terms of parental occupations and residence counties. Parental occupations and industries reported on birth certificates were qualitatively rated by industrial hygienists to estimate potential pesticide (list four groups) exposures. Residential exposures were estimated from agricultural census data according to county of residence. RESULTS: Neither parental exposure to pesticides [odds ratio (OR) 0.9, 95% confidence interval (95% CI) 0.6-1.4] nor farming occupation (OR 1.1, 95% CI 0.5-2.7) had an effect on the risk of total limb reduction defects. Those persons with limb reduction defects who had additional defects showed weak but consistent elevated risks in relation to parental occupational pesticide exposure. However, isolated cases of limb reduction defects were negatively related to these exposures. Residence in a farming or high pesticide use county was not associated with any type of limb reduction defect. CONCLUSIONS: Cases of limb reduction defect with additional malformations appear to be associated with parental occupational pesticide exposure. Improving exposure classifications and subdividing the limb reduction defects by types in the analyses are suggested for future research.

Adolescent↗
PubMed1998

Paternal exposure to pesticides and congenital malformations.

OBJECTIVES: A case-referent study with 261 matched pairs was carried out in 8 hospitals of Comunidad Valenciana, Spain, to assess the relation between occupational exposure to pesticides and selected congenital malformations. In this paper, the results concerning paternal exposure are presented. METHODS: The parents of the case patients and the referents were interviewed to collect information about exposure to pesticides and potential confounding variables. Detailed information on direct involvement in the handling of pesticides was collected for the interviewees involved in agricultural activities during a previously defined period in relation to conception and pregnancy. Exposure data were reviewed by 2 experts who assigned ordinal scores for the probability and intensity of exposure to pesticide classes and active ingredients. RESULTS: The dichotomous analysis of exposure (absent, present) yielded some increased risks, although not statistically significant, for aliphatic hydrocarbons [adjusted odds ratio (adjusted OR) 2.05, 95% confidence interval (95% CI) 0.62-6.80], inorganic compounds (adjusted OR 2.02, 95% CI 0.53-7.72), and glufosinate (adjusted OR 2.45, 95% CI 0.78-7.70), and a significant association for pyridil derivatives (adjusted OR 2.77, 95% CI 1.19-6.44). The analysis based on the experts' scores (2 levels of exposure) showed some consistent associations for these compounds. CONCLUSIONS: This research indicates a possible risk of congenital malformations for paternal exposure to some pesticides, notably, pyridils, aliphatic hydrocarbons, inorganic compounds, and glufosinate. It did not find an increased risk for paternal exposure to pesticides in the classes of organophosphates, carbamates, organochlorines, chloroalkylthio fungicides and organosulfurs. These findings warrant further investigation.

Agriculture↗
PubMedDate not supplied

Multiresidue screening of pesticides in foods using retention time locking, GC-AED, database search, and GC/MS identification.

Fruit and vegetable extracts were screened for over 400 pesticides by gas chromatography with atomic emission detection (GC-AED) and an experimental database. A technique called retention time locking was used to match GC-AED and GC with mass spectrometry (MS) retention times to those of the database. Samples were analyzed for sulfur, nitrogen, phosphorus, and chlorine by GC-AED. Possible pesticides were suggested by database search and identified by GC/MS. Forty-four pesticide standards were analyzed to determine the precision of retention time matching and the accuracy of the database search. Analytical retention times matched database retention times within 0.32 min. Using elemental criteria, the database search identified the correct compound for 41 of 44 pesticide standards. For blind spikes of fruit and vegetable extracts, the database suggested 22 of 26 spiked pesticides as matches. Nineteen were identified by GC/MS. The combination of retention time locking, GC-AED, database search, and GC/MS can be a powerful tool for identifying pesticides in a complex matrix.

Chlorine↗
PubMed1998

Private-public sector co-operation to improve pesticide safety standards in developing countries.

This paper draws on the author's experiences of the pilot phase of the Safe Use Project (SUP) in Thailand; this project is a part of a major GIFAP initiative carried out in some developing countries. The SUP's objectives were; i) to raise awareness and compliance in the safe handling and storage of pesticides within the industry, the medical profession and the end-users; ii) to reduce the incidence of pesticide poisoning; iii) to protect the environment; iiii) to help relevant government agencies with resources, expertise and training. To achieve those objectives, the SUP used local-language training resources, provided basic training, lobbied for changes in governmental policies and regulations, and acted as a focal point for pesticide safety-related information. The SUP targeted the whole distribution chain, from importer/formulator, through to the endusers. Also medical profession, teachers and school students were targeted. On the base of independent audit and surveys, a general improvement in awareness has been shown within targeted groups; a longer time frame is required to detect meaningful changes in farmer practice. The SUP key programmes have been: I) training of trainers, retailers and farmers; II) schools programme; III) medical training; IV) protective clothing; V) industry standards; VI) model farm. The main conclusions of the pilot phase were: i) pesticide safety needs to be addressed by all concerned agencies in a joint effort; ii) a rural development perspective must be adopted in improving pesticide safety; iii) integrated pest management training programmes must include precautionary advice for proper handling, use and disposal of pesticides, wherever these are necessary.

Developing Countries↗
PubMedDate not supplied

[Effect of pesticides on Bacillus thuringiensis strains under controlled conditions].

Little is known about native populations of Bacillus thuringiensis (Bt) isolated from soils of Argentina. We undertook this study to determine the resistance to different pesticides of two commercial and fourteen native strains of Bt under in vitro conditions. An agar plate bioassay test conducted with ten pesticides and sixteen strains of Bt showed that Basagran, Scepter, Fungoxan and Decis were not toxic for the bioinsecticide bacteria at recommended application rates (RAR). In contrast, low concentrations (3.2% RAR) of Agil, Select and Isomero showed a deleterious effect on the bacteria investigated. Simultaneously, four of the pesticides were able to produce phenotypical changes on the Bt colonies grown on nutrient agar. Moreover, in a greenhouse experiment, seven pesticides applied at 1.6%, 12.5% and 100% RAR on soybean leaves were not as inhibitory as under in vitro conditions for two Bt strains (HD-1 and A61). However, survival of these strains in the phyllosphere of soybean differed significantly between untreated leaves and leaves treated with pesticides after 20 days of study (P < 0.05). Finally, and from an ecological point of view, these findings suggest that the addition of some pesticides to soybean leaves in lower concentrations than those recommended could be favourable for the persistence of Bt in this environment.

Bacillus thuringiensis↗
PubMed1999

[Pesticides and time to pregnancy among Danish farmers].

The aim of this study was to examine time to pregnancy among farmers who used pesticides (traditional farmers) and farmers who did not (organic farmers). A total of 904 men, selected from the Danish Ministry of Agriculture lists of traditional and organic farmers, participated in telephone interviews. The participation rate was 84%. Information was collected on "time to pregnancy" for the youngest child, exposure to pesticides and potential confounders. Using the discrete analogue of the Cox Regression Model (including potential confounders: male and female smoking, female age, parity and contraceptive method), the fecundability ratio between traditional farmers using pesticides and organic farmers was 1.03 (95% CI: 0.75-1.40). In the group of farmers who sprayed with pesticides, none of the characteristics related to the use of pesticides could account for the variation in time to pregnancy. No overall effect of pesticides on male fecundability could be demonstrated in this retrospective study among Danish farmers.

Adult↗
PubMedDate not supplied

Bioavailable organochlorine pesticides in a semi-arid region of eastern Oregon, USA, as determined by gas chromatography with electron-capture detection.

A group of dissolved-bioavailable organochlorine (OC) pesticides and inorganic anions in water and total OC pesticides in sediments were measured in the Malheur Watershed, a semi-arid region in the western United States, over a 2-year period. OC pesticide levels were compared with those from a 1990 study of the lower section of the river, the most recent data available. After calculating the dissolved fraction from the 1990, study it seems that DDD and dieldrin levels have decreased in the water by 50-70%, while DDE and DDT have changed little. Although banned nearly 30 years ago, DDT is still persistent throughout the Malheur River basin/watershed because it was found in all water samples tested. All of the OC pesticides tested during the 2-year study are well below the criterion continuous concentration for aquatic community exposure as defined by the U.S. Environmental Protection Agency (EPA). OC pesticides appear to be decreasing, however, at lower Ontario there remains a human health risk (EPA Human Health Risk Water Quality Criteria) for DDT, because this criteria includes daily consumption of water and fish from the river. Overall, although the upper forest watershed sites have lower OC pesticide concentrations, they represent an important contribution to the total DDT load to this watershed, a source not previously acknowledged. The large increase in DDT and sigmaDDT between the Ontario sites may indicate a possible historical point source of contamination or historical preferential deposition of contamination. Normalized sediment (sigmaDDT/organic carbon) strongly correlates with dissolved water sigmaDDT.

Biological Availability↗
PubMedDate not supplied

Estimation of measurement uncertainty in pesticide residue analysis.

Proficiency test results from 5 countries involving 61 separate interlaboratory proficiency tests for pesticide residues were examined in this study. A total of 24 different matrixes and 869 relative standard deviations of the mean (or median) pesticide residue concentration were statistically evaluated in relation to the Horwitz function. The aim was to determine whether or not the concentration-dependent relationship described by Horwitz would hold for the much narrower range of chemicals and concentrations covered in routine pesticide residue analysis. Although for fatty (animal-derived) matrixes the variability increased as the concentration decreased in line with the Horwitz equation, the between-laboratories relative standard deviations for nonfatty matrixes (fruit, vegetables, and grain) remained at 25% over the entire concentration range of 1 microg/kg to 10 mg/kg for the pesticides studied. Given these findings, the Horwitz equation remains valid for calculating uncertainties involving pesticide residues in fatty matrixes. However, for pesticide residue analyses involving nonfatty matrixes, a constant relative standard deviation of 25% is more appropriate for calculating uncertainties, particularly when a reported result is assessed against a regulatory limit.

Data Interpretation, Statistical↗
PubMedDate not supplied

Size exclusion chromatographic cleanup for GC/MS determination of organophosphorus pesticide residues in household and vehicle dust.

Size exclusion chromatography (SEC) was used as a cleanup method for the analysis of organophosphorus pesticides in household and vehicle dusts. The pesticides investigated were diazinon, methyl parathion, chlorpyrifos, malathion, phosmet, and azinphosmethyl. These compounds are of interest due to their use in agricultural tree fruit production and/or urban pest control. Pesticides were determined via gas chromatography/mass spectrometry with selected-ion monitoring and cool on-column injection. The lower limit of method validation was 0.20 microg/g. Method limits of detection in dust ranged from 0.012-0.055 microg/g. Dust samples were collected with vacuums from the homes and vehicles of people living and working in a rural agricultural region in the central part of Washington State. The analytes were extracted from the dust by sonication in acetone. The extracts were solvent-exchanged to cyclohexane, frozen, thawed, and centrifuged prior to SEC injection. Following SEC, the eluent was split into 2 fractions, concentrated, and injected on-column into the gas chromatograph. This method represents the first complete publication describing the SEC cleanup of organophosphorus pesticides in dusts. Recoveries of pesticides in dusts ranged from 63.5-110.8 +/- 4.9-19.6% over a fortification range of 0.20-10.00 microg/g. This optimized, automated, and reproducible SEC method does not require further treatment or cleanup for trace determination of these organophosphorus pesticides.

Air Pollution, Indoor↗
PubMed2002

The agricultural dispersal-valley drift spray drift modeling system compared with pesticide drift data.

The coupling of the valley drift (VALDRIFT) atmospheric dispersion/deposition model with the agricultural dispersal (AGDISP) aircraft wake model generates a modeling system for predicting the off-target drift of pesticides sprayed in a mountain valley. The approach uses the AGDISP near-field spray model to estimate the mass fraction of pesticide remaining airborne after initial application, then the VALDRIFT complex terrain model to estimate the drift of pesticide from the target area. The modeling system inputs include detailed spray information, a measure (or estimate) of winds in the valley, and the valley topographic characteristics; the results are pesticide concentrations throughout the valley atmosphere and pesticide deposition to the valley surface. The AGDISP and VALDRIFT models are operated independently, with the results from AGDISP being used as input to VALDRIFT through user-created data files. The modeling system was evaluated using pesticide drift data from spray trials conducted in the Mill Creek Canyon of Utah's Wasatch Mountains, USA, during the late spring of 1993. The predicted deposition compared within a factor of three of the observations (70% of the time) at all sampling locations extending several kilometers down-valley from the spray treatment block. The overall average ratio of predicted-to-observed deposition was 0.9.

Agriculture↗
PubMed2002

Potential toxicity of pesticides measured in midwestern streams to aquatic organisms.

Society is becoming increasingly aware of the value of healthy aquatic ecosystems as well as the effects that man's activities have on those ecosystems. In recent years, many urban and industrial sources of contamination have been reduced or eliminated. The agricultural community also has worked towards reducing off-site movement of agricultural chemicals, but their use in farming is still growing. A small fraction, estimated at <1 to 2% of the pesticides applied to crops are lost from fields and enter nearby streams during rainfall events. In many cases aquatic organisms are exposed to mixtures of chemicals, which may lead to greater non-target risk than that predicted based on traditional risk assessments for single chemicals. We evaluated the potential toxicity of environmental mixtures of 5 classes of pesticides using concentrations from water samples collected from approximately 50 sites on midwestern streams during late spring or early summer runoff events in 1989 and 1998. Toxicity index values are calculated as the concentration of the compound in the sample divided by the EC50 or LC50 of an aquatic organism. These index values are summed within a pesticide class and for all classes to determine additive pesticide class and total pesticide toxicity indices. Toxicity index values greater than 1.0 indicate probable toxicity of a class of pesticides measured in a water sample to aquatic organisms. Results indicate that some samples had probable toxicity to duckweed and green algae, but few are suspected of having significant toxicity to bluegill sunfish or chorus frogs.

Animals↗
PubMed2002

Comparison of pesticide root zone model 3.12: leaching predictions with field data.

As part of a process to improve confidence in the results of regulatory modeling, predictions of the pesticide root zone model (PRZM) 3.12 were compared with measured data collected in nine different field leaching studies. Reasonable estimates of leaching were obtained with PRZM 3.12 in homogeneous soils where preferential flow is not significant. The PRZM 3.12 usually did a good job of predicting movement of bromide in soil (soil and soil pore-water concentrations were generally within a factor of two of predicted values). For simulations based on the best choices for input parameters, predictions of soil pore-water concentrations for pesticides were usually within a factor of three and soil pore-water estimates within a factor of 11. When the model input parameters were calibrated to improve the simulation of hydrology, predicted pesticide concentrations in soil pore water were usually within a factor of two of measured concentrations. Because of the sensitivity of leaching to degradation rate, the most accurate predictions were obtained with pesticides with relatively slow degradation rates. When conservative assumptions were used to define input pesticide parameters, predictions of pesticide concentrations were usually a factor of two greater than when using the best estimate of input parameters without any built-in conservatism.

Forecasting↗