Pesticides Of Different Chemical Classes Research Articles

Differential immunomodulatory effects of six pesticides of different chemical classes on human monocyte-derived macrophage functions

Exposure to pesticides through eyes, skin, ingestion and inhalation may affects human health by interfering with immune cells, such as macrophages. We evaluated, in vitro, the effect of six pesticides widely used in apple arboriculture on the functions of human monocyte-derived macrophages (hMDMs). hMDMs were cultured for 4 or 24 h with or without pesticides (0.01, 0.1, 1, 10 μmol.L-1). We showed that chlorpyrifos, thiacloprid, thiophanate, boscalid, and captan had little toxic effect at the tested concentrations, while dithianon had low-cytotoxicity at 10 μmol.L−1. While boscalid showed no effect on hMDMs function, thiophanate (0.01 μmol.L−1) stimulated with TPA and thiacloprid (1, 10 μmol.L−1) stimulated with zymosan activated ROS production. Chlorpyrifos, dithianon, and captan inhibited ROS production and TNF-α, IL-1β pro-inflammatory cytokines. We established that dithianon (0.01–1 μmol.L−1) and captan (0.1, 1 μmol.L−1) induced mRNA expression of NQO1 and HMOX1 antioxidant enzymes. Dithianon also induced the mRNA expression of catalase, superoxide dismutase-2 at 10 μmol.L−1. Together, these results show that exposure to chlorpyrifos, dithianon, and captan induce immunomodulatory effects that may influence the disease fighting properties of monocytes/macrophages while pesticides such as thiacloprid, thiophanate and boscalid have little influence.

Systematic Review of Calcium Channels and Intracellular Calcium Signaling: Relevance to Pesticide Neurotoxicity

Pesticides of different chemical classes exert their toxic effects on the nervous system by acting on the different regulatory mechanisms of calcium (Ca2+) homeostasis. Pesticides have been shown to alter Ca2+ homeostasis, mainly by increasing its intracellular concentration above physiological levels. The pesticide-induced Ca2+ overload occurs through two main mechanisms: the entry of Ca2+ from the extracellular medium through the different types of Ca2+ channels present in the plasma membrane or its release into the cytoplasm from intracellular stocks, mainly from the endoplasmic reticulum. It has also been observed that intracellular increases in the Ca2+ concentrations are maintained over time, because pesticides inhibit the enzymes involved in reducing its levels. Thus, the alteration of Ca2+ levels can lead to the activation of various signaling pathways that generate oxidative stress, neuroinflammation and, finally, neuronal death. In this review, we also discuss some proposed strategies to counteract the detrimental effects of pesticides on Ca2+ homeostasis.

Targeted Multiresidue Method for the Analysis of Different Classes of Pesticides in Agro-Food Industrial Sludge by Liquid Chromatography Tandem Mass Spectrometry.

Sludge generated after washing of fruits and vegetables during agro-food processes is a complex matrix and selective methods for the identification and quantification of pesticides’ residues are necessary in order to achieve a sustainable and effective management of the total sewage. The present work describes the development and validation of a reliable, simple and fast analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the determination of 47 pesticides of different chemical classes, including organosphosphates, pyrethroids, neonicotinoids, triazoles and others, in sludge samples after QuEChERS sample preparation. The necessity of the individual steps of QuEChERS was investigated and the LC-ESI-MS/MS conditions were optimized to achieve maximum sensitivity of the target analytes. The method limits of detection (LODs) ranged between 0.0005 mg/kg (imidacloprid) and 0.05 mg/kg (beta cyfluthrin). The recoveries ranged between 71–120% and the repeatability of the method was ≤25% expressed as relative standard deviation. The method was applied to sludge samples generated after washing of fruits in an agro-fruit-packaging unit in Greece. The results showed the presence of 37 pesticides’ active substances with concentrations ranging from low ppbs, such as fludioxinil (5 μg/kg) up to low ppms such as beta cyfluthrin (3.5 mg/kg) and with their sum concentration reaching up to 19 mg/kg.

Comprehensive strategy for pesticide residue analysis in cocoa beans through qualitative and quantitative approach

Multiresidue quantitative and qualitative screening method for the analysis of pesticide residues in dried cocoa beans was validated and applied to imported and domestic cocoa beans samples. The quantitative method comprises of 15 pesticides while the screening method covers 110 pesticides of different chemical classes. The method was based on modified QuEChERS (Quick Easy Cheap Efficient Rugged Safe) extraction and detection using triple quadrupole (QQQ-MS) and ion mobility quadrupole time of flight mass spectrometry (IMS-QTOF). The method was quantitatively validated in terms of linearity, limit of quantification (LOQ), specificity, selectivity, accuracy, and precision. On the other hand, screening detection limits were established for 110 pesticides. Finally, the optimized strategy was successfully applied for the routine analysis of pesticide residues in 137 cocoa bean samples and 32% of the total samples were found positive for ametryn, chlorpyrifos, isoprocarb, and metalaxyl.

Determination of pesticides of different chemical classes in drinking water of the state of Santa Catarina (Brazil) using solid-phase microextraction coupled to chromatographic determinations

The evaluation of the concentration of pesticides in drinking water presents a real concern. In this study, a simple and rapid method based on solid-phase microextraction (SPME) followed by gas chromatography-mass spectrometry and electron capture detectors was developed aiming at multiclass determination of 23 pesticides regulated by the Brazilian legislation. The extraction was carried out by direct immersion mode (DI-SPME) using DVB/Car/PDMS fiber coating. In order to improve the extraction efficiency, parameters such as temperature, salting-out effect, and extraction time were optimized. The method was evaluated using drinking water samples spiked with the analytes at different concentrations, and it showed good linearity in the range studied. The values obtained for limits of quantification (LOQ) were below the limits established by Brazilian regulations. Accuracy and precision of the method exhibited satisfactory results, providing relative recoveries from 70 to 123.34% at three spiked levels, and the relative standard deviations ranged from 0.53 to 24.8%. The method was applied in 20 drinking water samples from 13 cities in the State of Santa Catarina, Brazil.

Evaluation of alternative environmentally friendly matrix solid phase dispersion solid supports for the simultaneous extraction of 15 pesticides of different chemical classes from drinking water treatment sludge

This study describes the development, optimization and validation of a method for the extraction of 15 pesticides of different chemical classes in drinking water treatment sludge (DWTS) by vortex-assisted Matrix Solid Phase Dispersion (MSPD) with determination by gas chromatography coupled to mass spectrometry. It focused on the application of alternative and different solid supports to the extraction step of the MSPD. The main parameters that influenced the extraction were studied in order to obtain better recovery responses. Recoveries ranged from 70 to 120% with RSD below 20% for all analytes. Limits of quantification (LOQ) of the method ranged from 5 to 500 μg kg−1 whereas the analytical curves showed correlation coefficients above 0.997. The method under investigation used low volume of solvent (5 mL), low sample mass (1.5 g) and low mass of chitin (0.5 g), an environmentally friendly support. It has advantages, such as speed, simplicity and low cost material, over other methods. When the method was applied, 4 out of 15 pesticides were detected in the DWTS samples in concentrations below the LOQ.

Assessment of serum biomarkers in rats after exposure to pesticides of different chemical classes

There is increasing emphasis on the use of biomarkers of adverse outcomes in safety assessment and translational research. We evaluated serum biomarkers and targeted metabolite profiles after exposure to pesticides (permethrin, deltamethrin, imidacloprid, carbaryl, triadimefon, fipronil) with different neurotoxic actions. Adult male Long–Evans rats were evaluated after single exposure to vehicle or one of two doses of each pesticide at the time of peak effect. The doses were selected to produce similar magnitude of behavioral effects across chemicals. Serum or plasma was analyzed using commercial cytokine/protein panels and targeted metabolomics. Additional studies of fipronil used lower doses (lacking behavioral effects), singly or for 14days, and included additional markers of exposure and biological activity. Biomarker profiles varied in the number of altered analytes and patterns of change across pesticide classes, and discriminant analysis could separate treatment groups from control. Low doses of fipronil produced greater effects when given for 14days compared to a single dose. Changes in thyroid hormones and relative amounts of fipronil and its sulfone metabolite also differed between the dosing regimens. Most cytokine changes reflected alterations in inflammatory responses, hormone levels, and products of phospholipid, fatty acid, and amino acid metabolism. These findings demonstrate distinct blood-based analyte profiles across pesticide classes, dose levels, and exposure duration. These results show promise for detailed analyses of these biomarkers and their linkages to biological pathways.

Analysis of airborne pesticides from different chemical classes adsorbed on Radiello® Tenax® passive tubes by thermal-desorption-GC/MS.

An analytical methodology using automatic thermal desorption (ATD) and GC/MS was developed for the determination of 28 pesticides of different chemical classes (dichlobenil, carbofuran, trifluralin, clopyralid, carbaryl, flazasulfuron, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, cyprodinil, bromoxynil, fluroxypyr, oxadiazon, myclobutanil, buprofezin, picloram, trinexapac-p-ethyl, ioxynil, diflufenican, tebuconazole, bifenthrin, isoxaben, alphacypermethrin, fenoxaprop and tau-fluvalinate) commonly used in nonagricultural areas in atmospheric samples. This methodology was developed to evaluate the indoor and outdoor atmospheric contamination by nonagricultural pesticides. Pesticides were sampled passive sampling tubes containing Tenax® adsorbent. Since most of these pesticides are polar (clopyralid, mecoprop-P, dicamba, 2,4-MCPA, dichlorprop, 2,4-D, triclopyr, bromoxynil, fluroxypyr, picloram, trinexapac-p-ethyl and ioxynil), a derivatisation step is required. For this purpose, a silylation step using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MtBSTFA) was added before thermal desorption. This agent was chosen since it delivers very specific ions on electronic impact (m/z = M-57). This method was established with special consideration for optimal thermal desorption conditions (desorption temperature, desorb flow and duration; trap heating duration and flow; outlet split), linear ranges, limits of quantification and detection which varied from 0.005 to 10 ng and from 0.001 to 2.5 ng, respectively, for an uncertainty varied from 8 to 30 %. The method was applied in situ to the analysis of passive tubes exposed during herbicide application to an industrial site in east of France.

Coupling ASE, sylilation and SPME–GC/MS for the analysis of current-used pesticides in atmosphere

An analytical methodology using Accelerated Solvent Extraction (ASE) and a sylilation procedure coupled to Solid Phase Micro-Extraction (SPME) and GC/MS was developed for the determination of 31 pesticides of different chemical classes (urea, phenoxy acids, pyrethrenoïds, etc.) commonly used in non-agricultural areas in atmospheric samples. This methodology was developed to evaluate the outdoor atmospheric contamination by non-agricultural pesticides. Pesticides were simultaneously sampled on glass fibre filters and on XAD-2 resin traps by using a low volume sampler (Partisol) for 1 week. Traps were extracted by Accelerated Solvent Extraction (ASE) with acetonitrile and concentrated to 1 mL by using a rotary evaporator. 500 µL of the extract was dissolved in 19.5 mL of 1.5% NaCl acidified water (pH=3) and SPME extracted by PA fibre for 55 min at 50 °C. Since most of the studied pesticides are polar or thermo-labile, a derivatisation step by injection of 2 µL of MtBSTFA just before SPME desorption was done. MtBSTFA was chosen since it delivers very specific ions on electronic impact (m/z=M-57). Detection limits varied between 5 and 179 ng resin(-1) and between 0.3 and 126 ng filter(-1) corresponding to 2 and 750 pg m(-3) and 30 and 1165 pg m(-3) for 168 m(3) of air pumped through traps. Quantification limits varied between 18 and 595 ng resin(-1) and between 1 and 420 ng filter(-1) corresponding to 107 and 3542 pg m(-3) and 6 and 2500 pg m(-3) for 168 m(3) of air pumped through traps. Uncertainties varied between 7.2% and 39.6% and between 7.2% and 53.4% respectively for filter and resin. The method was used for the analysis of atmospheric samples collected in a background urban site of Strasbourg (east of France) during spring and summer 2010.

Development and validation of an easy multiresidue method for the determination of multiclass pesticide residues using GC–MS/MS and LC–MS/MS in olive oil and olives

Olives and olive oil are two of the most important commodities produced in the Mediterranean region. Due to their significant economical importance, the usage of pesticides in their production is systematic, by using a wide range of plant protection products with a variety of modes of action. As a consequence, monitoring of their residue levels in this products is a necessity. In the present study a gas and liquid chromatography-tandem mass spectrometry multiresidue method, with a short sample preparation step, based on acetonitrile extraction is developed and validated according to the European Union guidelines (SANCO Doc. No. 12495/2011) in olives and olive oil, with a large scope that includes pesticides of different chemical classes. Good sensitivity and selectivity of the method were obtained with limits of quantification at 10μg/kg. All pesticides had recoveries in the range of 70–120%, with relative standard deviation values less than 20–25%, at both validation levels. Excellent linearity was achieved with r≥0,99 for both matrices. The method is easy, with low consumption of reagents, is characterized by reliability, sensitivity and therefore is suitable for the monitoring the levels of multiclass pesticides residues in olives and olive oil. The method was applied to 262 samples of the Greek market, of which 7% were found positive for the present of pesticides. In some of the samples 2–8 different analytes were detected.

Distribution of pesticides in n-hexane/water and n-hexane/acetonitrile systems and estimation of possibilities of their extraction isolation and preconcentration from various matrices

Distribution of 150 most widely used pesticides of different chemical classes (amides, anilinopirimidines, aromatics, benzenesulfonates, carbamates, dicarboximides, organophosphorus compounds, phenyl esters, phenylureas, pyrazoles, pyrethroids, pyrimidines, strobilurins, sulfamides, triazines, triazoles, etc.) in n-hexane/water and n-hexane/acetonitrile systems was investigated at 25°C. Distribution constants of pesticides (P) have been calculated as ratio of pesticide concentration in n-hexane to its concentration in water or acetonitrile phase. HPLC and GC methods were used for pesticides determination in phases. It was found that the overwhelming majority of pesticides are hydrophobic, i.e. in n-hexane/water system LgP≫0, and the difference in LgP values can reach 9.1 units. Replacement of water for acetonitrile leads to dramatic fall of LgP values reaching 9.5 units. The majority of LgP values in this case are negative and their differences is strongly leveled in comparison with a hexane/water system. Thus, maximal difference in pesticides LgP values for n-hexane/acetonitrile system is 3.2 units. It is shown that n-hexane can be used for selective and efficient extraction and preconcentration of pesticides from water matrices. On the other hand, acetonitrile is effective for the isolation and preconcentration of pesticides from hydrocarbon and vegetable oil matrices. The distribution constants described in the paper may be effectively used for the estimation of possibilities of extraction isolation, preconcentration and separation of pesticides.

Pesticide residues in Brassica vegetables and exposure assessment of consumers

The presence of pesticide residues in Brassica vegetables (365 samples) produced in north-eastern Poland (2006–2009) was determined and their health risks assessed. The analytical procedure was developed to examine of 130 pesticides of different chemical classes (chloroorganic, phosphoroorganic, carbamates, strobilurines, neonicotinoids, amides, pyrimidines, benzimidazoles, imidazoles and triazoles) in broccoli, Brussels sprouts, cauliflower, head and Chinese cabbage. Pesticides were extracted using matrix solid phase dispersion (MSPD) and analyzed by gas chromatography (GC) with dual detection system: electron capture (ECD) and nitrogen–phosphorus (NPD). Linearity (R2 ≥ 0.997) was good over the concentration range from 2.5 to 0.001 mg/kg for all the pesticides, and instrumental detection limits ranged from 0.001 to 0.01 mg/kg. Mean recoveries for vegetables spiked at three fortification levels (0.001–2.5 mg/kg) ranged from 70.07 to 118.90%. Relative standard deviations ranged from 0.15 to 8.58%, except: dicofol, pyridaben (acaricides), dichloran (fungicide), isofenphos, triasophos (insecticides) where mean recoveries were above 120% (122.2–127%) and also dichlofluanid, tecnazene (fungicides), dichlobenil (herbicide), endosulfan-sulfate, phorate, phosmet (insecticides) with mean recoveries below 70% (42.83–69.1%). The method used to monitor pesticide residues in vegetables. Fifteen different pesticides (insecticides mainly) were detected in 118 samples (32%), while multiple pesticides (more than one pesticide residue) in about 4% samples. Chlorpyrifos and cypermethrin were the most commonly detected pesticides. Chlorpyrifos was present in 27.4% items and ranged from 0.005 to 1.51 mg/kg, while cypermethrin were detected in 3.3% samples and ranged from 0.02 to 0.19 mg/kg. Thirty-three (9%) samples exceeded the maximum residue levels (MRLs). The dietary intake of residues of some pesticides can pose acute hazards. Data obtained were then used for estimating the potential health risks associated with the exposures to these pesticides. The estimated daily intakes (EDIs) ranged from 0.005% of the ADI (acceptable daily intake) for fenhexamid to 4.454% of the ADI for diazinon. Combine cumulative exposure for chlorpyrifos detected on Brassica were 0.777% of ADI. The results show that occurrence of pesticide residues in Brassica vegetables from this region could not be considered a serious public health problem. Nevertheless, an investigation into continuous monitoring and tighter regulation of pesticide residues in vegetables is recommended.

Desenvolvimento de métodos analíticos para determinação de agrotóxicos em sedimentos por cromatografia gasosa monodimensional e bidimensional abrangente com micro detector de captura de elétrons

The development of analytical methods for determination of eight pesticides of different chemical classes (trichlorfon, propanil, fipronil, propiconazole, trifloxystrobin, permethrin, difenoconazole and azoxystrobin) in sediments with gas chromatography-micro-electron capture detector (GC/µECD) and comprehensive two-dimensional gas chromatography with micro-electron capture detector (GCxGC/µECD) is described. These methods were applied to real sediment samples, and the best results were obtained using a 5% diphenyl-methylpolysiloxane column for 1D-GC. For GCxGC the same column was employed in the first dimension and a 50%-phenyl-methylpolysiloxane stationary phase was placed in the second dimension. Due to the superior peak capacity and selectivity of GCxGC, interfering matrix peaks were separated from analytes, showing a better performance of GCxGC.

Multiresidue Analysis of 50 Pesticides in Grape, Pomegranate, and Mango by Gas Chromatography−Ion Trap Mass Spectrometry

A selective and sensitive multiresidue analysis method is reported for simultaneous determination of 50 pesticides of different chemical classes in three commercially important fruits of different nature viz. grape, pomegranate, and mango. The sample preparation method involves extraction of a 10 g sample with 10 mL of ethyl acetate; cleanup by dispersive solid phase extraction with primary secondary amine (PSA, 25 mg) for grape and PSA + graphitized carbon black (25 + 5 mg) for pomegranate and mango; and determination by gas chromatography-ion trap mass spectrometry through multiple reaction monitoring (MRM). Sample preparation under acidified (pH 4) and cold (<4 degrees C) conditions, use of PTV-large volume injection (20 microL) through multibaffled liner and chromatographic separation on a short 10 m VF-5MS capillary column gave a satisfactory response for all of the analytes including relatively unstable compounds such as captan, captafol, folpet, endrine, and iprodione within 31.8 min. The limit of quantification (LOQ) of most of the compounds was <or=10 ng g(-1) except for captan, captafol, and folpet, where the LOQ was <or=20 ng g(-1). For each analyte, the unique and most abundant MRM was selected for quantification, and the next most abundant for confirmation, with their abundance ratio being used for unambiguous identification of any detected pesticide in samples within 20% tolerance range at the LOQ level. Use of matrix-matched standards could minimize the matrix effect, which was lowest in grape, followed by pomegranate and mango. Recoveries ranged within 70-120% at 10, 20, and 50 ng g(-1) in all three matrixes with associated relative standard deviations <20% (n = 6). The method could be successfully applied to the screening of 100 farm samples for compliance to EU maximum residue limits.

Pesticide residues in river sediments from the Pantanal Wetland, Brazil

Sediment samples from 25 sites in 17 rivers of the Pantanal (Brazil) were analyzed with the objective of evaluating pesticide contamination in sediments. Samples were extracted with an acetone, ethylacetate, and water mixture 2:2:1 (v/v/v). The extract was purified by flash chromatography with aluminum oxide and florisil. A multiresidue gas chromatography-mass spectrometry method was applied to monitor 23 pesticides of different chemical classes (organochlorine, organophosphorus, triazines, anilides and pyrethroids) with some of their degradation products. Compounds identified in sediment samples included λ -cyhalothrin (1.0 to 5.0 μ g kg− 1), p,p′-DDT (3.6 μ g kg− 1), deltamethrin (20.0 μ g kg− 1) and permethrin (1.0 to 7.0 μ g kg− 1).

Fast GC–MS Pesticide Multiresidue Analysis of Apples

A fast gas chromatographic–mass spectrometric (GC–MS) method is proposed for pesticide multiresidue analysis of apples. The QuEChERS method was used for sample preparation. GC–MS analysis was performed with a PTV, an autoinjector, and a quadrupole benchtop MS detector. Electron-impact ionization (70 eV) was used with two modes of selected ion monitoring. Compounds were separated under temperature-programmed conditions on a narrow-bore diphenyldimethylsiloxane column. In one chromatographic run 61 pesticides of different chemical classes, and triphenyl phosphate as internal standard, were determined in 11 min. Calibration was performed with matrix-matched standard solutions and response to the pesticides was a linear function of concentration in the range 1–500 ng mL−1 (equivalent to 1–500 μg kg−1 in real samples). High values of the determination coefficients (R2; 0.9900–1.0000) were obtained for most of the pesticides. Limits of detection and quantification were determined. When the method was used for analysis of pesticide residues in real samples, five pesticides were detected at concentrations in the range 1.00–21.47 μg kg−1. Repeatability of measurements, expressed as relative standard deviations of absolute peak areas, normalized relative to TPP, and of the concentrations determined, met the EU criterion of RSD ≤ 20%. Use of the internal standard moderately improved quantitative results.

Development and validation of a multi-residue method for the determination of pesticides in processed fruits and vegetables using liquid chromatography–electrospray ionization tandem mass spectrometry

A sensitive multi-residue analytical method, utilizing ethyl acetate extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS), has been developed and validated for simultaneous determination of 28 pesticides of different chemical classes (polar organophosphates, carbamates, strobilurines, neonicotinoids, amides, pyrimidines, benzimidazoles, imidazoles and triazoles), and their transformation products, in processed fruit and vegetables. Two precursor-product ion transitions were monitored for each pesticide in selected reaction monitoring (SRM) mode. Linearity (r (2) > or = 0.99) was good over the concentration range 0.5 to 100 microg L(-1) for all the pesticides, and instrumental detection limits ranged from 0.1 to 1 microg L(-1). Mean recovery for fruit and vegetables spiked at 0.010 mg kg(-1) ranged from 65 to 94.4%, and relative standard deviations ranged from 9.0 to 20.0%. When the amount spiked was 0.050 mg kg(-1) recoveries ranged from 72.5 to 90% and relative standard deviations were from 6.1 to 19.0%. Method detection limits were from 0.002 to 0.007 mg kg(-1) for the different food matrices studied. The method was used to monitor pesticide residues in a wide variety of fruits and vegetables.

Increased ErbB-2 tyrosine kinase activity, MAPK phosphorylation, and cell proliferation in the prostate cancer cell line LNCaP following treatment by select pesticides.

The oncogene erbB-2 codes for a receptor tyrosine kinase that functions as a key mitotic signal in a variety of cell types. Amplification or overexpression of erbB-2 occurs in many forms of cancer, such as of the breast, colon, and prostate, and is an indicator of poor prognosis in those diseases. In the human prostate cancer cell lines LNCaP and PC-3, erbB-2 kinase was activated by pesticides of different chemical classes: (1) the organochlorine insecticides beta-hexa-chlorocyclohexane (beta-HCH), o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT), and heptachlor epoxide; (2) the pyrethroid insecticide trans-permethrin, and (3) the fungicide chlorothalonil. o,p'-DDT also causes phosphorylation of mitogen-activated protein kinase (MAPK) and cellular proliferation of the androgen-dependent LNCaP line. However, no proliferative effect was observed in the androgen-independent PC-3 line. The proliferative effect of o,p'-DDT in LNCaP could not be blocked by the androgen receptor antagonist p,p'-dichlorodiphenyldichloroethene (p,p'-DDE), indicating that this effect of o,p'-DDT does not occur through direct interaction with the androgen receptor. Together these data demonstrate a putative mechanism for the action of certain pesticides in hormonal carcinogenesis.

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 μg/1 to 6.0 0 μg/l and precision from 9.7% to 18% (as relative standard deviation of 1 μg/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.

New developments in pesticides for IPM in Africa with special reference to cotton pests

There is a large knowledge base available worldwide for growing many crops according to the principles of integrated pest management (IPM). CIBA-GEIGY is active in much IPM related research. Several biological control projects are being carried out at present and include studies of Trichogramma minutum against the spruce budworm in Canada; Encarsia sp. against glasshouse white-flies in Spain; the fungus Beauveria brongniartii against cockchafers in fruit gardens and forests of Switzerland and Italy; and the protozoan (Nosema) preparations against the African desert locust. In cotton, CIBA-GEIGY is concentrating on testing pesticides for the selectivity of beneficial arthropods under practical field conditions.Some of the most important pests in cotton, rice and vegetables are monitored regularly for the occurrence of resistance, and strategies are being developed to overcome it. A computer model has been developed for American cotton, which is now under practical evaluation and which should allow for appropriate treatment decisions based on plant phenology and regular pest scouting.General recommendations are given as to the implementation of IPM programmes in cotton, which are based on methodologically sound monitoring of cotton arthropods, establishment of economic thresholds, use of selective compounds or the selective use of broad spectrum pesticides, rotation of pesticides of different chemical classes to avoid the build-up of resistance, and a strengthened search for biological control alternatives such as more potent strains of Bacillus thuringiensis.