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PubMed1994

Estimation of long-term exposure to pesticides.

Quantifying the exposure of agricultural workers to pesticides is difficult in the face of the heterogeneity of the pesticides used, the variability in methods of application, and the lack of adequate exposure data. This report describes an attempt to estimate long-term dermal and inhalation exposure of bulb farmers by the development of an exposure index. This proposed exposure index consists of generic levels of exposure specific to the method of application, which were derived from databases as well as from field studies. The index is further determined by farm-related parameters such as acreage and number of pesticide applications ascertained from questionnaire responses. A widely used dithiocarbamate mixture served as a marker compound for exposure to other pesticides. Ranking of 127 bulb farmers according to calculated lifetime dermal exposure correlated only moderately to ranking based on duration of exposure, e.g., years of exposure and farm acreage. This finding indicates that the proposed exposure index could provide a useful estimate of long-term exposure to a mixture of pesticides in epidemiological investigations.

Agricultural Workers' Diseases↗

PubMed2004

CYP2D6 polymorphism, pesticide exposure, and Parkinson's disease.

We performed a case-control study of Parkinson's disease (PD) in a population characterized by a high prevalence of pesticide exposure and studied the joint effect of pesticide exposure and CYP2D6. Although they are based on a small group of subjects with the joint exposure, our findings are consistent with a gene-environment interaction disease model according to which (1) pesticides have a modest effect in subjects who are not CYP2D6 poor metabolizers, (2) pesticides' effect is increased in poor metabolizers (approximately twofold), and (3) poor metabolizers are not at increased PD risk in the absence of pesticide exposure.

Adolescent↗

PubMedDate not supplied

Protective effect of black tea extract on the levels of lipid peroxidation and antioxidant enzymes in liver of mice with pesticide-induced liver injury.

Sub-acute hepatotoxicity was induced in mice by exposure to pesticides. The effect of pretreatment with aqueous black tea extract on lipid peroxidation and antioxidants in the liver was investigated. Administering a combination dose of chlorpyriphos and cypermethrin (20 mg kg(-1) each) on alternate days over a 15-day period to male mice resulted in induction of sub-acute toxicity as reflected by elevated levels of liver damage marker enzymes alkaline phosphatase(ALP), aspartate transaminase(AST) and alanine transaminase(ALT). Significantly elevated levels of lipid peroxidation were observed in the experimental group (group III) as compared with control mice. Decreased activities of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), total thiol, glutathione peroxidase (GPx), glutathione reductase(GR) and glutathione-S-transferase (GST) were also observed in pesticide-treated as compared to control mice. Aqueous black tea extract was given as a pretreatment to group IV mice at a dose of 200 mg ml(-1) polyphenols before the pesticide dose, which significantly decreased the levels of lipid peroxidation and significantly elevated the activities of SOD, CAT, GSH, total thiol, GPx, GR and GST in liver to levels similar to the controls. Thus, the data offer support for the claim that the central mechanism of pesticide action occurs via changes in cellular oxidative status and shows conclusively that supplementation with black tea extract protects against the free radical-mediated oxidative stress in hepatocytes of animals with pesticide-induced liver injury.

Administration, Oral↗

PubMed2005

Combining solid-phase microextraction and on-line preconcentration-capillary electrophoresis for sensitive analysis of pesticides in foods.

The combined use of solid-phase microextraction (SPME) and different on-line preconcentration strategies for ultrasensitive capillary electrophoresis-ultraviolet (CE-UV) analysis of five pesticides in a single run is investigated. Normal stacking mode (NSM), field-enhanced sample injection (FESI), and stacking with matrix removal (SWMR) are explored to increase the sensitivity of the CE-UV analysis of a selected group of pesticides (cyprodinil, cyromazine, pyrifenox, pirimicarb, and pyrimethanil). It could be observed that reverse polarity-stacking with matrix removal (RP-SWMR) provided the best results in terms of sensitivity (enhancement was up to 272-fold compared with normal injection). The separation buffer consisted of 0.4 mM cetyltrimethylammonium chloride (CTAC), 0.4 M acetic acid at pH 4 containing 5% v / v 2-propanol. This approach was then combined with SPME to determine the pesticides in water, apple, and orange juice. The combination of both preconcentration procedures allowed the determination of these pesticides at concentrations down to 2.5 microg / L in water and 3.1 microg / L in juices (i.e., levels well below the maximum residue limits allowed for these compounds). To our knowledge, this is the first report showing the great possibilities of the combined use of SPME, on-line sample preconcentration, and CE for pesticide analysis.

Carbamates↗

PubMed2006

DNA damage in Pakistani pesticide-manufacturing workers assayed using the Comet assay.

The production and use of chemical pesticides has increased in recent years. Although the increased use of pesticides may benefit agriculture, they are also the potential source of environmental pollution, and exposure to pesticides can have negative consequences for human health. In the present study, we have assessed DNA damage in blood leukocytes from 29 Pakistani pesticide-factory workers and 35 controls of similar age and smoking history. The workers were exposed to various mixtures of organophosphates, carbamates, and pyrethroids. DNA damage was measured with the single cell gel electrophoresis (SCGE) assay or Comet assay, using the mean comet tail length (microm) as the DNA damage metric. Exposed workers had significantly longer comet tail lengths than the controls (mean +/- SD 19.98 +/- 2.87 vs. 7.38 +/- 1.48, P < 0.001). Of the possible confounding factors, smokers had significantly longer mean comet tail lengths than nonsmokers and exsmokers for both the workers (21.48 +/- 2.58 vs.18.37 +/- 2.28, P < 0.001) and the controls (8.86 +/- 0.56 vs. 6.79 +/- 1.31, P < 0.001), while age had a minimal effect on DNA damage (P > 0.05 and P < 0.05 for workers and controls, respectively). The results of this study indicate that occupational exposure to pesticides causes DNA damage.

Adult↗

PubMed1991

Frequency of sister chromatid exchange in peripheral lymphocytes of male pesticide applicators.

In the present study 61 male pesticide applicators who worked in cotton fields and regularly sprayed pesticides such as DDT, BHC, endosulfan, malathion, methyl parathion, phosphamidon, dimethoate, monocrotophos, quinalphos fenvelrate, and cypermethrin were analyzed for sister chromatid exchanges, mitotic index, and cell cycle kinetics in peripheral lymphocytes. Subjects who handled pesticides were non-smokers and teetotalers and the data were compared with the matched control group. Statistical analysis revealed that the frequency of sister chromatid exchanges was significantly higher among the pesticide applicators at all the durations of exposure when compared to controls. Subjects exposed to pesticides also showed cell cycle delay and decrease in mitotic index when compared to the control group.

Adult↗

PubMed2026

Pesticide occurrence, transformation, and transport from wastewater treatment plants into stream networks with diverse land uses.

Neonicotinoid insecticides and strobilurin fungicides are detected in many environmental compartments and have been associated with negative environmental and human health implications. Wastewater treatment plants (WWTPs) are often hotspots for introducing such contaminants into the environment. Therefore, the occurrence of strobilurin fungicides, neonicotinoids, and their metabolites at two WWTPs with varying land uses and population sizes was investigated. Polar organic chemical integrative samplers were deployed in WWTP influent and effluent and placed upstream and downstream of the effluent mixing zone for 2 weeks in April and July 2022. Biosolids were also collected at each time point. Neonicotinoids were detected with the highest frequency (68%), followed by strobilurin fungicides (49%) and neonicotinoid metabolites (31%). Time-weighted average concentrations for influent/effluent ranged from 85.2 ± 87.8 to 409.4 ± 74.5 ng/L. Pesticide concentrations, specifically the metabolites, typically increased from influent to effluent, resulting in effluent having higher pesticide loads than influent. Pesticide concentrations varied between the upstream and downstream monitoring locations by analyte, with WWTP samples in the highly developed region having significantly higher concentrations of pesticides and less variation by monitoring period. Chronic ecotoxicity benchmarks for freshwater invertebrates for imidacloprid were surpassed in treated effluent at both WWTPs in July and in the downstream monitoring location in the heavily developed area. Findings support the need for further exploration of pesticide contributions from WWTPs to river systems, specifically related to metabolite contributions to downstream streams and their effects on aquatic environments.

Water Pollutants, Chemical↗

PubMed2005

Can agrobiont spiders (Araneae) avoid a surface with pesticide residues?

Integrated pest management includes the use of various pesticides that can have a detrimental effect on spiders. A pesticide can express its activity directly or via residues. Most of the attention paid to the impact of pesticides on spiders has investigated the effects of direct exposure. Our aim in this study was to investigate the residual activity (repellency and toxicity) of selected pesticides on six principal species of spider occurring in an apple orchard. Four of these species (Clubiona spp., Pardosa spp., Philodromus spp., Xysticus spp.) are hunting spiders, and two species (Dictyna spp., Theridion spp.) are web-building. We were interested to see whether these spiders could avoid a surface with residues and to examine their susceptibilities to fresh and 1-day-old residues. For this purpose we conducted laboratory experiments using three types of pesticide, an organophosphate, phosalone (Zolone), a pyrethroid, permethrin (Ambush) and Bacillus thuringiensis (Bt; Novodor), which were applied to paper discs or branches. Spiders could choose to stay on any treated paper/branch within a dish. Except for Theridion spp., all species were repelled by fresh residues but not by 1-day-old residues. Clubiona spp., Dictyna spp., Pardosa spp. and Xysticus spp were repelled by phosalone and permethrin residues only, whereas Philodromus spp. specimens were repelled also by Bt residues. Theridion spp. avoided contact with residues by making a web on any available branch. Regarding toxicity, neither fresh nor 1-day-old residues of phosalone or Bt caused significant mortality to any spider species. In contrast, both fresh and 1-day-old residues of permethrin caused significant mortality to all species except for Theridion spp. In conclusion, spiders can recognise and avoid only fresh residues, although older residues might still be toxic to them.

Animals↗

PubMed2006

Acceptability of pesticide impacts on the environment: what do United Kingdom stakeholders and the public value?

EU Directive 91/414/EEC requires there to be no unacceptable effects on the environment from the use of pesticides. This paper reports the views of direct stakeholder groups and results from an opinion survey of more than 2000 members of the general public on what in practice should constitute acceptable and unacceptable effects of pesticides. Stakeholders in focus groups were concerned with the potential effects of pesticides on animal and plant population viability and micro-organism function but recognized that a trade-off exists between the potential economic advantages of responsible pesticide use and the potential disadvantages of individual poisoning events. The public opinion survey showed that although pesticides are widely used in homes and gardens, their use on farm crops remains of concern to the public. Concerns are greatest on issues of human health and food quality but potential environmental effects are also an issue for a substantial number of people, particularly if attractive species could be affected.

Animals↗

PubMed2006

Dynamics of pesticide residues in the autumn Chinese cabbage (Brassica chinensis L.) grown in open fields.

Residues of the pesticides chlorpyrifos, dimethoate, cyhalothrin, cypermethrin, fenvalerate, deltamethrin and chlorothalonil in the autumn Chinese cabbage (Brassica chinensis L.) were studied using gas chromatography. The results indicated that the residues were dependent on the frequency and rate of pesticide application and on the weather conditions immediately following spraying. When the Chinese cabbages were treated once at normal rates, the half-lives of the seven pesticides in the vegetable were 4.7, 5.3, 2.9, 3.5, 5.4, 4.3 and 4.0 days respectively. Thus, based on the recommended preharvest intervals, the residual levels of all pesticides were within the national standards. When the Chinese cabbages were treated four times at maximal rates at 5 day intervals, the half-lives of chlorpyrifos, cypermethrin and chlorothalonil in the vegetable were 3.6, 2.9 and 5.9 days respectively, so that, based on the recommended preharvest intervals, the residual levels of chlorpyrifos and chlorothalonil exceeded the national standards for pollution-free vegetables, but the residual level of cypermethrin was within the national standard. Effects of rain on pesticide final residues in plants treated four times were more significant than in those treated once.

Agriculture↗

PubMed2006

Uncalibrated modelling of conservative tracer and pesticide leaching to groundwater: comparison of potential Tier II exposure assessment models.

The Root Zone Water Quality Model (RZWQM) and Pesticide Root Zone Model (PRZM) are currently being considered by the Office of Pesticide Programs (OPP) in the United States Environmental Protection Agency (US EPA) for Tier II screening of pesticide leaching to groundwater (November 2005). The objective of the present research was to compare RZWQM and PRZM based on observed conservative tracer and pesticide pore water and soil concentrations collected in two unique groundwater leaching studies in North Carolina and Georgia. These two sites had been used previously by the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Environmental Model Validation Task Force (EMVTF) in the validation of PRZM. As in the FIFRA EMVTF PRZM validation, 'cold' modelling using input parameters based on EPA guidelines/databases and 'site-specific' modelling using field-measured soil and hydraulic parameters were performed with a recently released version of RZWQM called RZWQM-NAWQA (National Water Quality Assessment). Model calibration was not performed for either the 'cold' or 'site-specific' modelling. The models were compared based on predicted pore water and soil concentrations of bromide and pesticides throughout the soil profile. Both models tended to predict faster movement through the soil profile than observed. Based on a quantitative normalised objective function (NOF), RZWQM-NAWQA generally outperformed or was equivalent to PRZM in simulating pore water and soil concentrations. Both models were more successful in predicting soil concentrations (i.e. NOF < 1.0 for site-specific data, which satisfies site-specific applicability) than they were at predicting pore water concentrations.

Environment↗

PubMed2006

Pesticide exposure assessment in rice paddies in Europe: a comparative study of existing mathematical models.

A comparative test was undertaken in order to identify the potential of existing mathematical models, including the rice water quality (RICEWQ) 1.6.4v model, the pesticide concentration in paddy field (PCPF-1) model and the surface water and groundwater (SWAGW) model, for calculating pesticide dissipation and exposure in rice paddies in Europe. Previous versions of RICEWQ and PCPF-1 models had been validated under European and Japanese conditions respectively, unlike the SWAGW model which was only recently developed as a tier-2 modelling tool. Two datasets, derived from field dissipation studies undertaken in northern Italy with the herbicides cinosulfuron and pretilachlor, were used for the modelling exercise. All models were parameterized according to field experimentations, as far as possible, considering their individual deficiencies. Models were not calibrated against field data in order to remove bias in the comparison of the results. RICEWQ 1.6.4v provided the highest agreement between measured and predicted pesticide concentrations in both paddy water and paddy soil, with modelling efficiency (EF) values ranging from 0.78 to 0.93. PCPF-1 simulated well the dissipation of herbicides in paddy water, but significantly underestimated the concentrations of pretilachlor, a chemical with high affinity for soil sorption, in paddy soil. SWAGW simulated relatively well the dissipation of both herbicides in paddy water, and especially pretilachlor, but failed to predict closely the pesticide dissipation in paddy soil. Both RICEWQ and SWAGW provided low groundwater (GW) predicted environmental concentrations (PECs), suggesting a low risk of GW contamination for the two herbicides. Overall, this modelling exercise suggested that RICEWQ 1.6.4v is currently the most reliable model for higher-tier exposure assessment in rice paddies in Europe. PCPF-1 and SWAGW showed promising results, but further adjustments are required before these models can be considered as strong candidates for inclusion in the higher-tier pesticide regulatory scheme.

Environmental Exposure↗

PubMed2003

The influence of lipophilicity and formulation on the distribution of pesticides in laboratory-scale sediment/water systems.

Pesticide reaching surface waters will be sorbed by sediment. This sorption process and the influence of pesticide formulation have been examined at 10 degrees C in small-scale systems having 2-cm depth of sediment and 8-cm overlying water stirred gently. Eight pesticides (triasulfuron, isoproturon, chlorotoluron, phenmedipham, difenoconazole, chlorpyrifos, pendimethalin and permethrin), spanning a range of physicochemical properties, were applied individually to the water. Sorption equilibrium was reached at between 15 and 30 days, the proportion of pesticide then in the sediment ranging from 20% for the acidic and therefore polar triasulfuron to 97% for the lipophilic permethrin; this behaviour was not influenced by formulation. Sorption coefficients measured in batch tests over 2 h gave good estimates of the equilibrium distribution. Some degradation was observed for all compounds over 90 days; for some compounds and formulations, enhanced degradation occurred after 20 to 60 days. It is concluded that lipophilicity is the chief determinant of pesticide distribution in sediment/water systems.

Algorithms↗

PubMed2003

Pesticide buffer zones for the protection of wildlife.

Buffer zones can play important roles in agricultural habitats, both in the protection of off-crop habitats from pesticide and fertiliser drift and run-off, and in providing important areas of non-crop habitats. Their role in the protection of aquatic habitats from pesticide drift is a significant feature of pesticide risk management, but they are currently used only to a limited degree to protect terrestrial habitats. This paper summarises some of the evidence for the risks and impacts of pesticide drift into non-crop habitats, and the approaches taken by the nature conservation agencies in deriving buffer zones for the protection of sites that are important for nature conservation. Biodiversity objectives need to be explicitly built into ICM programmes, and buffer zones, together with appropriate application technology, can play an important part in reducing pesticide drift in ICM systems to achieve such objectives.

Agriculture↗

PubMed2005

A study of the disappearance of pesticides during composting using a gas chromatography-tandem mass spectrometry technique.

A simple method for multi-residue analysis of pesticides by low-pressure gas chromatography-tandem mass spectrometry (LP-GC-MS-MS) has been validated in compost samples. The pesticide residues were extracted from the lyophilised samples with organic solvent by stirring. No sample clean-up was required prior to the analysis. The method was applied to determine the fate of two organochlorine pesticides (lindane and endosulfan) and two organophosphates (malathion and chlorpyrifos-methyl) during the composting process in the reactor of a pilot plant. Malathion, chlorpyrifos-methyl and lindane residues almost fully disappeared after 8 days of maturation in the reactor, while endosulfan residues were only partially degraded. Alongside this, a study of natural disappearance of the pesticides was carried out in the laboratory and a characteristic time profile was traced for each pesticide class.

Biodegradation, Environmental↗

PubMed2006

Validation of a gas chromatography/triple quadrupole mass spectrometry based method for the quantification of pesticides in food commodities.

A new multiresidue method has been validated in cucumber matrix for the routine analysis of 130 multiclass pesticide residues by gas chromatography/triple quadrupole mass spectrometry. The pesticides were extracted with ethyl acetate. A first identification of the pesticides was based on a tandem mass spectrometric (MS/MS) screening method, which monitors a single transition for each target compound, in less than 12 min. After that, potentially non-negative samples were analyzed again by the MS/MS confirmation/quantification method, which monitors two or three MS/MS transitions for each compound, also in less than 12 min. Performance characteristics, such as trueness, precision, linear range, detection limit (LOD) and quantification limit (LOQ), for each pesticide were calculated. The average recoveries obtained ranged between 70 and 120% at three different fortification levels (25, 200 and 500 microg/kg) with precision, expressed as relative standard deviation (RSD), values lower than 15%. The calculated LOD and LOQ were typically <3.2 and 9.6 microg/kg, respectively. Such limits were much lower than the maximum residue levels (MRLs) established by European legislation. The proposed methodology was applied to the determination of pesticides in real vegetable samples from Almería (Spain).

Calibration↗

PubMed2006

Simultaneous determination of 109 pesticides in unpolished rice by a combination of gel permeation chromatography and Florisil column purification, and gas chromatography/mass spectrometry.

A multi-residue method is described for the simultaneous analysis of 109 pesticides with different properties in unpolished rice. The range covers organophosphorus, organochlorine, carbamate, and synthetic pyrethroid pesticides. The pesticides were extracted from the sample using ethyl acetate. Most higher molecular weight components such as lipids in the co-extractives were removed by gel permeation chromatography (GPC) with a Bio-bead SX-3 column. A Florisil column with ethyl acetate/hexane as the eluting solvents was used for further cleanup. The pesticides were finally simultaneously determined by gas chromatography/mass spectrometry (GC/MS) in selective ion monitoring (SIM) mode. The average recoveries for most pesticides (spiked level 0.02, 0.1 and 1 microg/g) ranged from 70% to 110%, the relative standard deviation (RSD) was below 20% in every case, and the limit of detection (LOD) varied from 1 to 20 ng/g.

Chromatography, Gel↗

PubMed2006

Study of automated mass spectral deconvolution and identification system (AMDIS) in pesticide residue analysis.

The effects of overlapping levels and concentration ratios of overlapping components, and of scan rates of the mass spectrometer, on the capability of the automated mass spectral deconvolution and identification system (AMDIS) in pesticide residue analysis were studied. To investigate the capability of AMDIS in removing interferences from the overlapping peaks, this system was applied to data files obtained from the gas chromatography/mass spectrometry (GC/MS) analysis of two overlapping (co-eluting) pesticides (beta-HCH and PCNB) in full scan mode. Differences in overlap levels, the concentration ratios of the two overlapping components and the scan rates of the instrument were studied. When the difference in scan number of overlapping compounds was equal to 1 scan, AMDIS incompletely extracted 'purified' mass spectra but as the difference increased to 3 or more scans, complete correct spectra could be extracted. The results also show that when the scan rate was in the range of 0.4-0.90 s/scan and the concentration ratios of the target compound/interference were above 1/5, there were ideal deconvolution results for this approach. To further study the application of AMDIS to pesticide residue analysis, AMDIS was applied to the identification of pesticides spiked in real samples (cabbage and rice). Typical pesticides being evaluated were identified using AMDIS at concentrations >50 ng/g in the extracts.

Brassica↗