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PubMed1998

Determination of N-methylcarbamate pesticides in foods using an accelerated solvent extraction with a mini-column cleanup.

Residual N-methylcarbamate pesticides in food were determined by accelerated solvent extraction (ASE) and HPLC with post-column fluorescence. Pesticides were extracted with acetonitrile at 100 degrees C under 2000 psi pressure in less than 20 min. Extracts were cleaned-up with a carboxylic acid mini-column eluted with 10% or 30% acetone in hexane. Eight foods were spiked with 17 pesticides at 0.2 ppm. The average recoveries of these pesticides were 70-100% and the relative standard deviations were < 10%. These results suggested that ASE can be used to extract residues of N-methylcarbamate pesticides in foods.

Carbamates↗
PubMed1998

Supercritical fluid extraction of pesticides from meat: a systematic approach for optimisation.

A method for quantification of pesticide residues in meat and fatty matrices was developed using supercritical fluid extraction (SFE). The SFE method allows selective extraction of residues and subsequent gas chromatography analysis without further clean-up. Quantification was done by GC using nitrogen-phosphorus detection and electron capture detection. Initial method development was made using organophosphorus pesticides (OPPs). The dependence of fat and OPP residue recovery on supercritical fluid density, temperature, flow rate and extraction time was investigated through a reduced factorial design. Since temperature and density were found to have pronounced effect on the recovery of OPPs these extraction parameters were studied using a new arbitrary measure for co-extractivity. An optimisation score was established as relative pesticide recovery subtracted by relative fat recovery. Using this algorithm a response plane was modelled varying the primary factors temperature and density. The applicability of this approach and the algorithm was verified. The polarity range covered by the SFE method was demonstrated using OPPs: chlorpyrifos, chlorpyrifos-methyl, malathion, pirimifos-methyl and prothiofos. Additionally the final method was evaluated using four pesticides that are not OPPs: carbofuran, phorate, procymidone and vinclozolin. All pesticides showed good recovery (78-95%), and limits of detection (0.01-0.03 mg kg-1) and limits of determination (0.01-0.05 mg kg-1) meet the requirements set by the European Council (Directive 96/33/EEC). Compared to traditional methods based on organic solvent extraction, the SFE method is fast, less labour intensive, uses smaller amounts of potentially harmful solvents and has the potential to be fully automated.

Animals↗
PubMed2000

Determination of pesticides in soil samples by supercritical fluid chromatography-atmospheric pressure chemical ionisation mass spectrometric detection.

This paper presents an analytical technique for the determination of pesticides in soil by packed-column supercritical fluid chromatography interfaced with atmospheric pressure chemical ionisation mass spectrometry (pSFC-APCI-MS). The technique provides a versatile method for the detection and quantification of pesticides belonging to three different commonly used classes, triazines (ametryne, atrazine), carbamates (carbofuran) and sulfonylureas (chlorsulfuron, metsulfuron methyl and benzsulfuron methyl). The APCI mass spectra for all the pesticides studied consisted of protonated molecule ions as the most abundant ion at low cone voltages, except for metsulfuron methyl and benzsulfuron methyl, which gave a fragment ion as the most abundant ion with the protonated molecule ion at low intensity. Increasing the cone voltage provided informative fragmentation patterns for all species. The technique shows good linearity over the concentration range of 0.1-50 micrograms ml-1, with r2 values as follows: atrazine 0.997, ametryne 0.995, carbofuran 0.999, benzsulfuron methyl 0.999, chlorsulfuron 0.995 and metsulfuron methyl 0.997. The detection limits in the selected ion mode were atrazine 201, ametryne 144 and carbofuran 385 pg, which were calculated by using the standard solution, and benzsulfuron methyl 2.045, chlorsulfuron 1.435 and metsulfuron methyl 2.414 ng, which were determined by using spiked soil samples. The pSFC-MS system was shown to have a high degree of reproducibility. The technique was then applied to the determination of the above pesticides in soil samples. The results obtained show that there is no matrix effect from the soil and that the detection limits for all pesticides in soil were similar to those found for the standard solutions.

Chromatography, Ion Exchange↗
PubMed2000

A study on the behaviour of pesticides and their transformation products in the Scheldt estuary using liquid chromatography-electrospray tandem mass spectrometry.

Off-line solid-phase extraction (SPE) combined with liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS-MS) was used to study the estuarine behaviour of the polar pesticides, atrazine, chloridazon, diuron and metolachlor, and their transformation products (TPs), hydroxyatrazine (HA), desisopropylatrazine (DIA), desethylatrazine (DEA), 3,4-dichlorophenylmethylurea (DPMU) and monuron. The compounds were identified by comparing their LC retention times and product-ion spectra with those of standard solutions. In all but one case the detection limits of the method were sufficient to determine the compounds of interest over the entire salinity range in the estuary. The concentrations of the dissolved pesticides ranged from 70 ng l-1 for chloridazon to 1350 ng l-1 for diuron. The levels of TPs were 3-8% of the levels of their parent pesticide. The mixing plots of polar pesticides and their TPs indicated that TPs, which are present in fresh river water, are conservatively transported to the sea and that no additional amounts of TPs are formed during their transport through the estuary. The one exception was HA, of which approximately 10% of the amount transported to the North Sea is formed in the lower part of the estuary by photochemical oxidation of atrazine. The latter was concluded from the ratios of each analyte over the sum total of the parent pesticide and all TPs along the salinity gradient, which proved to be a useful tool for identifying such estuarine transformations.

Chromatography, Liquid↗
PubMed2001

Multiresidue analysis of pesticides in vegetables and fruits using two-layered column with graphitized carbon and water absorbent polymer.

A high-throughput multiresidue analysis of pesticides in non-fatty vegetables and fruits was developed. The method consisted of a single extraction and a single clean-up procedure. Food samples were extracted with ethyl acetate and the mixture of extract and food dregs were poured directly into the clean-up column. The clean-up column consisted of two layers of water-absorbent polymer (upper) and graphitized carbon (lower), which were packed in a reservoir (75 ml ) of a cartridge column. The polymer removed water in the extract while the carbon performed clean-up. In a recovery test, 110 pesticides were spiked and average recoveries were more than 95% from spinach and orange. Most pesticides were recovered in the range 70-115% with RSD usually < 10% for five experiments. The residue analyses were performed by the extraction of 12 pesticides from 13 samples. The two methods resulted in similar residue levels except chlorothalonil in celery, for which the result was lower with the proposed method. The results confirmed that the proposed method could be applied to monitoring of pesticide residue in foods.

Food Contamination↗
PubMedDate not supplied

Pesticide exposure in a farming village in Venezuela--a developing country.

This study was designed and performed by the Universidad de Carabobo, Centro de Investigaciones Toxicológicas, Venezuela, and the University of Cincinnati Department of Environmental Health. The authors tested methodology and analyzed preliminary data on demographics, pesticide use, health, environment, and lifestyles in a farming community in Venezuela (population = 386; sample size = 81) to determine if pesticide misuse might have been contributing to public health problems. Questionnaire and geographic information were collected. There were statistically significant incidences of pesticide-related symptoms (p < .01) in farmers versus nonfarmers (odds ratio = 5.7; 95% confidence interval = 2.9, 18.8). In addition, in one area there was a cluster of farmers who experienced symptoms that appeared to be the result of foul air and proximity to farms where there was pesticide use. The results of the study indicated that this public health problem may have been associated with pesticide misuse; however, additional studies are needed to corroborate the findings.

Adolescent↗
PubMed2003

Persistent organochlorine pesticides in Mexican butter.

Organochlorine pesticides have been used in Mexico in malaria control programmes against ectoparasites and as seed dresser. Owing to their chemical stability, they tend to accumulate in the lipid part of the organisms. The stored pesticides are excreted with the endogenous fat during milk production. The aim was to monitor the organochlorine pesticide levels in butter manufactured in Mexico. From the pesticides, only HCB, beta-HCH, pp'-DDT, op'-DDT and pp'-DDE with major frequency and levels were detected. The HCB mean level was low at 0.008 mg kg(-1) on a fat basis. From the HCH isomer, only the beta-HCH at 0.065 mg kg(-1) on a fat basis was determined, remaining as the main contaminant of the monitored butters. Among DDTs, pp'-DDE was the major constituent (0.043 mg kg(-1) on a fat basis) followed by pp'-DDT (0.036 mg kg(-1)) and op'-DDT (0.009 mg kg(-1)). Comparing the previous study (1994) and this one (2001), all organochlorine pesticides had a descendent tendency; beta-HCH decreased from 0.095 to 0.065 mg kg(-1) on a fat basis, whereas the total DDT decreased from 0.056 to 0.047 mg kg(-1), pp'-DDT from 0.050 to 0.036 mg kg(-1), op'-DDT from 0.018 to 0.009 mg kg(-1), while pp'-DDE increased from 0.032 to 0.043 mg kg(-1). The decreased DDT levels in Mexican butters is caused by the substitution of organochlorine insecticides with pyrethroids used by the Mexican Ministry of Health since 1999 in sanitary programmes.

Animals↗
PubMed2005

Investigation into the validity of extrapolation in setting maximum residue levels for pesticides in crops of similar morphology.

Field trials were initiated to investigate if extrapolation procedures, which were adopted to limit costs of pesticide registration for minor crops, are valid. Three pairs of crops of similar morphology; carrots/swedes, cauliflower/calabrese (broccoli) and French beans/edible-podded peas; were grown in parallel at four different geographical locations within the UK. The crops were treated with both systemic and non-systemic pesticides under maximum registered use conditions, i.e. the maximum permitted application rates and the minimum harvest intervals. Once mature, the crops were harvested and analysed for residues of the applied pesticides. The limits of quantification were in the range 0.005-0.02 mg kg(-1). Analysis of variance and bootstrap estimates showed that in general, the mean residue concentrations for the individual pesticides were significantly different between crop pairs grown on each site. Similarly, the mean residue concentrations of most of the pesticides in each crop across sites were significantly different. These findings demonstrate that the extrapolations of residue levels for most of the selected pesticide/crop combinations investigated; chlorfenvinphos and iprodione from carrots to swedes; carbendazim, chlorpyrifos, diflubenzuron and dimethoate from cauliflower to calabrese; and malathion, metalaxyl and pirimicarb from French beans to edible-podded peas; appear invalid.

Food Analysis↗
PubMed2005

Pesticide residues survey in citrus fruits.

The use of pesticides is widespread in citrus fruits production for pre- and post-harvest protection and many chemical substances may be applied in order to control undesirable moulds or insects. A survey was carried out to evaluate levels of pesticide residues in citrus fruits. Two multiresidue analytical methods were used to screen samples for more than 200 different fungicides, insecticides and acaricides. A total of 240 samples of citrus fruits including lemon, orange, mandarin, grapefruit, lime, pomelo and kumquat were taken in various markets in the Geneva area during the year 2003. Ninety-five percent of the 164 samples issued from classical agriculture contained pesticides and 38 different compounds have been identified. This high percentage of positive samples was mainly due to the presence of two post-harvest fungicides, imazalil and thiabendazole, detected in 70% and 36% of samples respectively. Only three samples exceeded the Swiss maximum residue limits (MRLs). Fifty-three samples sold with the written indication "without post-harvest treatment" were also controlled. Among theses samples, three exceeded the Swiss MRLs for penconazole or chlorpyrifos and 18 (34%) did not respect the written indication since we found large amounts of post-harvest fungicides. Finally, 23 samples coming from certified organic production were analysed. Among theses samples, three contained small amounts of pesticides and the others were pesticides free.

Agriculture↗
PubMed1998

Determination of pesticide residues in wine by SPME and GC/MS for consumer risk assessment.

An analytical procedure applying solid phase microextraction (SPME) combined with gas chromatography/ mass spectrometry (GC/MS) for the detection of pesticide residues in wine was performed for the determination of 14 of the pesticides most frequently used on grapes (insecticides, fungicides, herbicides). As SPME combines the possibility of a single-step extraction with other advantages (short sampling times, solvent-free procedure, speedy extraction, low cost and simplicity) it could be successfully used either for screening or routine analysis for detecting pesticides of different chemical classes in wines, even at trace levels. The analytical procedure performed showed minimum detectable quantities ranging from 0.10 microgram/l to 6.0 micrograms/l and precision from 9.7% to 18% (as relative standard deviation of 1 microgram/l levels), assuring high sensitivity and precision of analysis. Twenty-one wine samples (10 white wines and 11 red wines) available on the Italian market were analysed with the procedure described and about 57% were positive for one or more pesticides. An approach for consumer risk assessment on the basis of the data obtained was proposed for further assessments of the daily dietary intake of pesticides through wine.

Calibration↗
PubMed2006

Behavior of pesticides in sediment/water systems in outdoor mesocosms.

The distribution of eight pesticides between sediment and water held in 1-m square outdoor stainless-steel mesocosms was studied, simulating both spring and autumn applications. Pesticide behavior was largely independent of rate of application, chosen in the first three experiments to be 4% or 40% of the normal field rate so as to simulate spray drift or partial overspray. Following application by spray to the water surface, all compounds were uniformly distributed in the 30 cm of overlying water within 24 h. The lipophilic pesticides (chlorpyrifos, pendimethalin, and permethrin) moved into the sediment within 30 d but with little penetration below 2.5 cm depth, and only chlorpyrifos persisted beyond 30 d. The mass balance of these lipophilic pesticides at 1 d was only 26.3% to 61%, with these initial losses attributed to processes such as volatilization. Isoproturon and chlorotoluron persisted for around 120 d, remaining largely in the overlying water with a maximum of 15% in the sediment. Permethrin and difenoconazole were much less persistent in these mesocosms, with very little ever found in the sediment in contrast to previous findings in laboratory-scale stirred systems as used in registration tests. The polar mecoprop remained almost entirely in the water phase and was rapidly degraded. Two further experiments examined also the influence of the submerged plant Lagarosiphon major in the mesocosms, the first experiment simulating a full-rate overspray with chlorpyrifos and linuron and the second a repeat in spring of the earlier main autumn experiment. Both chlorpyrifos and linuron applied in the autumn were quite persistent over the winter period, with about 20% still remaining after 152 d. Uptake into L. major was correlated with pesticide lipophilicity, but was only a small factor compared to uptake by sediment and degradation in these lightly vegetated systems.

Ecosystem↗
PubMed1980

Mutagenicity evaluation of chemical pesticides.

Over the last few decades, the use of chemical pesticides has increased dramatically in the U.S. This relatively sudden increase greatly concerns the U.S. Environmental Protection Agency (EPA), since it has the responsibility for ensuring the safety of all pesticides used in the U.S. In response to this concern, EPA has established a review program, the Rebuttable Presumption Against Registration (RPAR), for periodically reassessing the mutagenic and carcinogenic potential of pesticide compounds. This paper presents a review and evaluation of the data reported in the literature on six chemical pesticides suspect for mutagenic potential. The pesticide chemicals discussed are maleic hydrazide; rotenone; monuron; diallate; triallate, and benomyl.

Animals↗
PubMed1987

The effects of various soil factors and amendments on the degradation of pesticide mixtures.

Soil disposal is the most common method of handling dilute pesticide wastes. The effects of several soil factors on the degradation of a pesticide mixture were investigated. Atrazine, captan, carbaryl, 2,4-D, diazinon, fenitrothion, and trifluralin were studied under varying laboratory conditions of soil type, pH, moisture content, organic matter content, microbial activity, and pesticide concentration. Of the variables investigated, pesticide concentration was the single most important factor with degradation rates much slower at high (1000 ppm) levels of fortification than moderate (100 ppm) levels. Under most conditions, chemical degradation was at least as significant as microbial degradation. Effects of other factors varied considerably and were pesticide dependent.

Biodegradation, Environmental↗
PubMed1990

Pesticide contamination of ground water in the United States--a review.

Over 70 pesticides have been detected in ground water. Aldicarb and atrazine along with the soil fumigants EDB and DCP and DBCP have been the pesticides most frequently detected in ground water. Atrazine concentrations have been correlated with high nitrate concentrations. The triazine herbicides, simazine and cyanazine, have also been detected in ground water. The annual amount of recharge, soil type, depth of aquifer from the surface, nitrate contamination and soil pH are important field parameters in determining ground-water contamination potential by pesticides. Pesticide leaching is reduced by proper choice of crop rotation, increasing pesticide application efficiency, and integrated pest management.

Acetamides↗
PubMed1990

Measurements of surface contamination of spray equipment with pesticides after various methods of application.

A traditional method to determine operator dermal exposure is to quantify the amount of pesticide coming into contact with specific body regions and then to integrate the deposition density values with the total body surface. It is known that extremely high deposition values may occur in the hand region; however, the source of contamination is generally assumed to be direct splash or contact with the pesticide container. One of the parameters affecting operator/pilot exposure could be the transfer of pesticide residue, particularly in the case of pesticides with a longer half-life, from contaminated surfaces of spray equipment by direct contact over extended periods. If the rate of skin absorption of pesticide is readily known, the expected values of daily dose for an operator or pilot may significantly rise due to the extended contact period. This study produced field data on the surface contamination of spray equipment used for ground and aerial applications. If field data on precise work practice (time-motion) observations are incorporated, it may be possible to estimate the potential exposure of operator/pilot due to hand contact with contaminated surfaces.

Aerosols↗
PubMed2004

Comparison of gravimetric and gas chromatographic methods for assessing performance of textile materials against liquid pesticide penetration.

Penetration of liquid pesticides through textile materials is a criterion for determining the performance of protective clothing used by pesticide handlers. The pipette method is frequently used to apply liquid pesticides onto textile materials to measure penetration. Typically, analytical techniques such as Gas Chromatography (GC) are used to measure percentage penetration. These techniques are labor intensive and costly. A simpler gravimetric method was developed, and tests were conducted to compare the gravimetric and GC methods of analysis. Three types of pesticide formulations and 4 fabrics were used for the study. Diluted pesticide formulations were pipetted onto the test specimens and percentage penetration was measured using the 2 methods. For homogeneous formulation, the results of the two methods were fairly comparable. However, due to the filtering action of the textile materials, there were differences in the percentage penetration between the 2 methods for formulations that were not homogeneous.

Analysis of Variance↗
PubMedDate not supplied

Addressing the linkage between exposure to pesticides and human health effects--research trends and priorities for research.

In recent years, there has been escalating concern over the possible association between exposure to pesticides and adverse human health effects by a number of non-governmental organizations, professional and public interest groups. Recognizing the need to document the scientific basis of these concerns as a foundation for initiating a research theme devoted to linkages between exposures to pesticides and human health effects, the Canadian Institutes of Health Research (CIHR) requested a summary of recent research trends that address these linkages. Experts across Canada in the field of pesticide regulation and research were invited to participate in the review. The review summarizes the limitations of past and current studies related to pesticides and human health effects research and makes suggestions for future research priorities and proposed study designs that will improve the assessment of pesticide exposure, the associated health risks, and improved methodology for regulatory decision making.

Canada↗
PubMed2005

Parental occupational exposure to pesticides and childhood germ-cell tumors.

In a recently completed US case-control study (Children's Oncology Group, 1993-2001) with 253 cases and 394 controls, the authors investigated the association between parental occupational exposure to pesticides and risk of childhood germ-cell tumors. Information on occupational pesticide exposure was collected using job-specific module questionnaires and assessed by an experienced industrial hygienist. Odds ratios for childhood germ-cell tumors associated with maternal exposures before pregnancy, during pregnancy, and after the birth of the index child were 1.0 (95% confidence interval (CI): 0.8, 1.4), 1.1 (95% CI: 0.7, 1.6), and 1.3 (95% CI: 0.9, 1.8), respectively. Paternal exposures before pregnancy, during pregnancy, and after the birth of the index child were not related to germ-cell tumors (odds ratios (ORs) were 0.9 (95% CI: 0.7, 1.2), 0.8 (95% CI: 0.5, 1.2), and 0.8 (95% CI: 0.5, 1.3), respectively). When both parents had ever been occupationally exposed to pesticides before the index pregnancy, the odds ratio was 0.8 (95% CI: 0.4, 1.3). Subgroup analyses showed a positive association between maternal exposure to herbicides during the postnatal period and risk of germ-cell tumors in girls (OR = 2.3, 95% CI: 1.0, 5.2) and an inverse association between paternal exposure to pesticides during the index pregnancy and germ-cell tumors in boys (OR = 0.2, 95% CI: 0.1, 1.0). This study did not provide strong evidence supporting a relation between parental pesticide exposure in the workplace and risk of germ-cell tumors among offspring.

Adolescent↗