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Bulletin of Environmental Contamination... Apr 2016Surface water sampling in 2007-2010 measured the occurrence of carbamates and metalaxyl during base flow conditions and wet weather events in southern Ontario surface...
Surface water sampling in 2007-2010 measured the occurrence of carbamates and metalaxyl during base flow conditions and wet weather events in southern Ontario surface waters. Carbaryl, metalaxyl and pirimicarb were the most frequently detected compounds. In 2008 these three compounds were detected in over 50 % of the samples. Overall mean concentrations of carbaryl and metalaxyl over the course of the study (2007-2010) were 15 and 18 ng/L, respectively. Elevated concentrations of carbaryl (~100 to ~950 ng/L) appeared associated with wet weather (high flow) events, while highest concentrations of metalaxyl (~20-1330 ng/L) were correlated with base flow conditions. We attributed these observations as the result of runoff of carbaryl from the watershed during rain events, while metalaxyl contamination may have resulted primarily from spray drift.
Topics: Alanine; Carbamates; Carbaryl; Environmental Monitoring; Fresh Water; Ontario; Pesticides; Pyrimidines; Rain; Water Pollutants, Chemical
PubMed: 26754544
DOI: 10.1007/s00128-015-1719-x -
EXCLI Journal 2015A dramatic increase in pesticide usage in agriculture highlights the need for on-site monitoring for public health and safety. Here, a paper-based sensor combined with a...
A dramatic increase in pesticide usage in agriculture highlights the need for on-site monitoring for public health and safety. Here, a paper-based sensor combined with a wet system was developed for the simple and rapid screening of organophosphate (OP) and carbamate (CM) pesticides based on the inhibition of acetylcholinesterase (AChE). The paper-based sensor was designed as a foldable device consisting of a cover and detection sheets pre-prepared with indoxyl acetate and AChE, respectively. The paper-based sensor requires only the incubation of a sample on the test zone for 10 minutes, followed by closing of the foldable sheet to initiate the enzymatic reaction. Importantly, the buffer loading hole was additionally designed on the cover sheet to facilitate the interaction of the coated substrate and the immobilized enzyme. This subsequently facilitates the mixing of indoxyl acetate with AChE, resulting in the improved analytical performance of the sensor. The absence or decrease in blue color produced by the AChE hydrolysis of indoxyl acetate can be observed in the presence of OPs and CMs. Under optimized conditions and using image analysis, the limit of detection (LOD) of carbofuran, dichlorvos, carbaryl, paraoxon, and pirimicarb are 0.003, 0.3, 0.5, 0.6, and 0.6 ppm, respectively. The assay could be applied to determine OP and CM residues in spiked food samples. Visual interpretation of the color signal was clearly observed at the concentration of 5 mg/kg. Furthermore, a self-contained sample pre-concentration approach greatly enhanced the detection sensitivity. The paper-based device developed here is low-cost, requires minimal reagents and is easy to handle. As such, it would be practically useful for pesticide screening by non-professional end-users.
PubMed: 26417364
DOI: 10.17179/excli2014-684 -
Roczniki Panstwowego Zakladu Higieny 2015Peaches, sour cherries, nectarines, apricots, plums and cherries are fruit commonly known as "stone fruit". Their nutritional properties namely, vitamins, minerals,...
BACKGROUND
Peaches, sour cherries, nectarines, apricots, plums and cherries are fruit commonly known as "stone fruit". Their nutritional properties namely, vitamins, minerals, fiber and numerous microelements, make them a very important component of human diet. As fruit trees can be attacked by numerous diseases and pests, chemical protection of these crops is used. Therefore, it is important that the relevant governmental agencies or institutions ensure correct application of pesticides.
OBJECTIVE
The aim of the study was to evaluate the occurrence of pesticide residues in stone fruits south-eastern region of Poland in 2012-2014 in order to provide data to estimate health risk to consumers.
MATERIAL AND METHODS
Validated analytical methods based on liquid / liquid extraction coupled with gas chromatography with electron capture and nitrogen phosphorus detection (GC-ECD/NPD) and spectrophotometry (dithiocarbamates residues) were used for the analysis. 92 samples of stone fruits were tested for the presence of pesticide residues.
RESULTS
13 of all samples (14%) contained pesticide residues. 7 active substances were detected, including 5 fungicides: boscalide, bupirimate, difenoconazole, dithiocarbamates and captan, and 2 insecticides: cypermethrin and pirimicarb. In the analysed samples, the use of not recommended plant protection products in orchard crops were found. However, neither maximum residue levels (MRLs) recommended by the Regulation (EC) No 396/2005 were exceeded nor pesticides being unapproved by the Regulation (EC) No 1107/2009 detected in the analysed samples.
CONCLUSIONS
Lack of plant protection products for control specific diseases or pests in crops results in the use of formulations not recommended for use in certain orchard crops. On a basis of results reported in previous years it can be concluded that occurrence of pesticide residues in stone fruit samples dropped significantly.
Topics: Bridged Bicyclo Compounds; Dioxolanes; Endosulfan; Food Contamination; Fruit; Humans; Insecticides; Maximum Allowable Concentration; Pesticide Residues; Pesticides; Poland; Pyrimidines; Thiocarbamates; Triazoles
PubMed: 26400116
DOI: No ID Found -
PloS One 2015The wheat aphids, Rhopalosiphum padi (Linnaeus) and Sitobion avenae (Fabricius), are key pests on wheat crops worldwide. Management practices rely primarily on...
The wheat aphids, Rhopalosiphum padi (Linnaeus) and Sitobion avenae (Fabricius), are key pests on wheat crops worldwide. Management practices rely primarily on insecticides. The pirimicarb (carbamate) is used extensively as an effective insecticide to control these two aphids. In addition to the mortality caused by pirimicarb, various sublethal effects may occur in aphids when exposed to low lethal or sublethal doses. Understanding the general effect of pirimicarb on aphids could help increasing rational use of this insecticide. Under laboratory conditions, we assessed the sublethal effects of a low lethal concentration of pirimicarb (LC25) on biological traits and acetylcholinesterase (AChE) activity of R. padi and S. avenae. Both direct and transgenerational effects, i.e. on parent and the F1 generations were assessed, respectively. We found that R. padi and S. avenae responded differentially to the LC25 of pirimicarb. The parent generation of R. padi showed a 39% decrease in fecundity and multiple transgenerational effects were observed in the F1 generation; overall juvenile development, reproductive period, adult longevity and lifespan were longer than those of the control group. By contrast, LC25 of pirimicarb showed almost no effects on S. avenae biological traits in both the parent and F1 generations; only the pre-reproductive duration was reduced in F1 generations. Demographic parameter estimates (e.g. rm) showed similar trend, i.e. significant negative effect on R. padi population growth and no effect on S. avenae. However, AChE activity decreased in both R. padi and S. avenae treated by the LC25 of pirimicarb. We demonstrated sublethal and transgenerational effects of pirimicarb in the two wheat aphid species; it hinted at the importance of considering sublethal effects (including hormesis) of pirimicarb for optimizing Integrated Pest Management (IPM) of wheat aphids.
Topics: Acetylcholinesterase; Animals; Aphids; Carbamates; Crosses, Genetic; Female; Fertility; Longevity; Male; Pyrimidines; Triticum
PubMed: 26121265
DOI: 10.1371/journal.pone.0128936 -
Bioinformation 2014Glutathione S-transferases (GSTs) are one of the major families of detoxifying enzymes that detoxifies different chemical compounds including insecticides in different...
Glutathione S-transferases (GSTs) are one of the major families of detoxifying enzymes that detoxifies different chemical compounds including insecticides in different insect species. Among the GST subclasses, sigma GSTs are found to be the most abundant and conserved among different insect orders. These GSTs are found to play an important role in lipid peroxidation as well as detoxification. Cotton aphid, Aphis gossypii is the most damaging sucking pest with a wide range of hosts and vector of more than 50 plant viruses. Resistance to insecticides in A. gossypii is reported in India and in other countries. Glutathione S transferases (GSTs), an oxidative enzyme is understood to have a role in insecticide resistance and plant resistance breakdown. In relation to this, we have focused on the sigma 1 (GenBank Accession No: JN989964.1) and sigma 2 (GenBank Accession No: JN989965.1) GSTs of A. gossypii and their interaction with plant natural compounds and insecticides. Molecular screening of different insecticides (Chlorphinamidine, Mevinphos, Nitenpyrum, Piperonyl butoxide, Tetrachlorovinphos, Pyrethrins, Resmetrin, Pirimicarb and Dinotefuran) and known plant derived natural compounds (Catechin, Gossypol, Myrcene, Kaempferol, P-coumaric acid, Quercetin, Tannins, α-mangostin, Capsaicin, Cinnamic acid, Citronellal, Curcumin, Dicumarol, Ellagic acid, Eugenol, Geriniol, Isoeugenol, Juglone, Menadione, Methyl jasmonate, Morin, Myricetin, Myristicin, Piperine, Plumbagin, Tangitinin C, Thymol, Vanillin, Alpha pipene, α-terpineol Apigenin and β-Caryophyllene) with sigma 1 and sigma 2 GST protein models was completed using Maestro 9.3 (Schrodinger, USA). This exercise showed the binding of piperonyl butoxide with sigma 1 GST and tannin with sigma 2 GST for further consideration.
PubMed: 25512683
DOI: 10.6026/97320630010679 -
BioMed Research International 2014Pesticides are used throughout the world as mixtures called formulations. They contain adjuvants, which are often kept confidential and are called inerts by the...
Pesticides are used throughout the world as mixtures called formulations. They contain adjuvants, which are often kept confidential and are called inerts by the manufacturing companies, plus a declared active principle, which is usually tested alone. We tested the toxicity of 9 pesticides, comparing active principles and their formulations, on three human cell lines (HepG2, HEK293, and JEG3). Glyphosate, isoproturon, fluroxypyr, pirimicarb, imidacloprid, acetamiprid, tebuconazole, epoxiconazole, and prochloraz constitute, respectively, the active principles of 3 major herbicides, 3 insecticides, and 3 fungicides. We measured mitochondrial activities, membrane degradations, and caspases 3/7 activities. Fungicides were the most toxic from concentrations 300-600 times lower than agricultural dilutions, followed by herbicides and then insecticides, with very similar profiles in all cell types. Despite its relatively benign reputation, Roundup was among the most toxic herbicides and insecticides tested. Most importantly, 8 formulations out of 9 were up to one thousand times more toxic than their active principles. Our results challenge the relevance of the acceptable daily intake for pesticides because this norm is calculated from the toxicity of the active principle alone. Chronic tests on pesticides may not reflect relevant environmental exposures if only one ingredient of these mixtures is tested alone.
Topics: Caspases; Cell Membrane; Dose-Response Relationship, Drug; Environmental Exposure; HEK293 Cells; Hep G2 Cells; Humans; Mitochondria; Pesticides
PubMed: 24719846
DOI: 10.1155/2014/179691 -
BioMed Research International 2014In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena) (n = 16), purchased from four different markets in Dhaka,...
In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena) (n = 16), purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC), and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50%) of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb) and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl) were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40-48%, 35-43%, and 30-45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85-90%, 80-91%, and 90-95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80-95% of some pesticides.
Topics: Bangladesh; Carbamates; Chromatography, High Pressure Liquid; Environmental Monitoring; Gamma Rays; Organophosphorus Compounds; Pesticide Residues; Vegetables
PubMed: 24711991
DOI: 10.1155/2014/145159 -
PloS One 2014Pesticide resistance monitoring is a crucial part to achieving sustainable integrated pest management (IPM) in agricultural production systems. Monitoring of resistance...
BACKGROUND
Pesticide resistance monitoring is a crucial part to achieving sustainable integrated pest management (IPM) in agricultural production systems. Monitoring of resistance in arthropod populations is initially performed by bioassay, a method that detects a phenotypic response to pesticides. Molecular diagnostic assays, offering speed and cost improvements, can be developed when the causative mutation for resistance has been identified. However, improvements to throughput are limited as genotyping methods cannot be accurately applied to pooled DNA. Quantifying an allele frequency from pooled DNA would allow faster and cheaper monitoring of pesticide resistance.
METHODOLOGY/PRINCIPAL FINDINGS
We demonstrate a new method to quantify a resistance allele frequency (RAF) from pooled insects via TaqMan assay by using raw fluorescence data to calculate the transformed fluorescence ratio k' at the inflexion point based on a four parameter sigmoid curve. Our results show that k' is reproducible and highly correlated with RAF (r >0.99). We also demonstrate that k' has a non-linear relationship with RAF and that five standard points are sufficient to build a prediction model. Additionally, we identified a non-linear relationship between runs for k', allowing the combination of samples across multiple runs in a single analysis.
CONCLUSIONS/SIGNIFICANCE
The transformed fluorescence ratio (k') method can be used to monitor pesticide resistance in IPM and to accurately quantify allele frequency from pooled samples. We have determined that five standards (0.0, 0.2, 0.5, 0.8, and 1.0) are sufficient for accurate prediction and are statistically-equivalent to the 13 standard points used experimentally.
Topics: Animals; Aphids; Australia; Carbamates; Fluorescence; Gene Frequency; Genotyping Techniques; Gossypium; Insecticide Resistance; Plasmids; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Polymorphism, Single Nucleotide; Pyrimidines; Reference Standards; Seasons; Taq Polymerase
PubMed: 24614533
DOI: 10.1371/journal.pone.0091104 -
Journal of Insect Science (Online) 2013The aphids Sitobion avenae (Fabricius) and Rhopalosiphum padi (Linnaeus) (Hemiptera: Aphidiae) are serious pests on grain crops and usually coexist on late period of... (Comparative Study)
Comparative Study
The aphids Sitobion avenae (Fabricius) and Rhopalosiphum padi (Linnaeus) (Hemiptera: Aphidiae) are serious pests on grain crops and usually coexist on late period of wheat growth in China. Bioassays showed that R. padi was more susceptible than S. avenae to pirimicarb that is used for wheat aphid control, and the determination of acetylcholinesterase (AChE, EC 3.1.1.7) sensitivity showed that the sensitivity of AChE to pirimicarb was significantly higher in R. padi than in S. avenae ( Lu and Gao 2009 ). AChE is the target enzyme of the carbamates, including pirimicarb, hence, to understand the mechanism responsible for the tolerance difference to carbamate insecticides of S. avenae and R. padi, we purified AChE from both aphid species using procainamide affinity column and characterized the AChE. The purification factor and yield from S. avenae (234.7-fold and 92.9%) were far higher than that from R. padi 17.3-fold and 13.9%. The results of substrate and inhibitor specificities of purified enzyme from both S. avenae and R. padi indicated that the purified enzyme was a typical AChE. The crude AChE extract from S. avenae was 5.4-, 4.3- and 8.1-fold less sensitive to inhibition by pirimicarb, methomyl and thiodicarb, respectively, than that from R. padi, whereas for the purified AChE, S. avenae was only 1.6-, 1.3- and 1.7-fold less sensitive to inhibition by pirimicarb, methomyl and thiodicarb, respectively, than R. padi. This suggests that eserine and BW284C51 may bind with other proteins, such as carboxylesterase, in the crude extract to reduce their inhibition against AChE. These results are useful for planning the chemical control of aphids on wheat.
Topics: Acetylcholinesterase; Animals; Aphids; Kinetics; Substrate Specificity
PubMed: 23879406
DOI: 10.1673/031.013.0901 -
Talanta Mar 2013This study focused on the development of a sensitive enzymatic biosensor for the determination of pirimicarb pesticide based on the immobilization of laccase on...
This study focused on the development of a sensitive enzymatic biosensor for the determination of pirimicarb pesticide based on the immobilization of laccase on composite carbon paste electrodes. Multi-walled carbon nanotubes (MWCNTs) paste electrode modified by dispersion of laccase (3%, w/w) within the optimum composite matrix (60:40%, w/w, MWCNTs and paraffin binder) showed the best performance, with excellent electron transfer kinetic and catalytic effects related to the redox process of the substrate 4-aminophenol. No metal or anti-interference membrane was added. Based on the inhibition of laccase activity, pirimicarb can be determined in the range 9.90 × 10(-7) to 1.15 × 10(-5) mol L(-1) using 4-aminophenol as substrate at the optimum pH of 5.0, with acceptable repeatability and reproducibility (relative standard deviations lower than 5%). The limit of detection obtained was 1.8 × 10(-7) mol L(-1) (0.04 mg kg(-1) on a fresh weight vegetable basis). The high activity and catalytic properties of the laccase-based biosensor are retained during ca. one month. The optimized electroanalytical protocol coupled to the QuEChERS methodology were applied to tomato and lettuce samples spiked at three levels; recoveries ranging from 91.0 ± 0.1% to 101.0 ± 0.3% were attained. No significant effects in the pirimicarb electroanalysis were observed by the presence of pro-vitamin A, vitamins B1 and C, and glucose in the vegetable extracts. The proposed biosensor-based pesticide residue methodology fulfills all requisites to be used in implementation of food safety programs.
Topics: Biosensing Techniques; Carbamates; Electrochemical Techniques; Electrodes; Food Analysis; Food Safety; Humans; Insecticides; Laccase; Lactuca; Limit of Detection; Solanum lycopersicum; Nanotubes, Carbon; Pyrimidines; Reproducibility of Results; Substrate Specificity
PubMed: 23598106
DOI: 10.1016/j.talanta.2012.12.017