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Chemosphere Dec 2020Organophosphorus insecticides are known to be partly transformed to their respective oxons during the chlorination step of drinking water treatment. For most...
Effect of chlorination on anti-acetylcholinesterase activity of organophosphorus insecticide solutions and contributions of the parent insecticides and their oxons to the activity.
Organophosphorus insecticides are known to be partly transformed to their respective oxons during the chlorination step of drinking water treatment. For most organophosphorus insecticides, the toxicological endpoint for determining acceptable daily intake levels is inhibition of acetylcholinesterase (AChE). Like the parent insecticides, oxons also inhibit AChE, so the presence of oxons in drinking water is also evaluated. However, no attention is paid to the possible presence of transformation products (TPs) other than oxons. In the present study, we determined whether the anti-AChE activity observed for chlorinated solutions of the organophosphorus insecticides malathion and methidathion could be solely attributed to the parent compounds and their oxons. Upon chlorination, both malathion and methidathion were immediately transformed to their oxons; the maximum transformation ratios were 60% and 30%, respectively, indicating that at least 40% and 70% of these compounds were transformed into other TPs. Before chlorination, malathion- and methidathion-containing solutions exhibited little to no anti-AChE activity, but the solutions showed strong activity after chlorination. The contributions of the parent insecticides and their oxons to the activities of the chlorinated samples were calculated from the concentrations of the compounds in the samples and dose-response curves for chemical standards of the compounds. For both the malathion-containing solution and the methidathion-containing solution, the calculated anti-AChE activities were almost the same as the observed activities at every chlorination time. This suggests that the observed activities could be attributed solely to the parent insecticides and their oxons, indicating that other TPs need not be considered.
Topics: Acetylcholinesterase; Animals; Cholinesterase Inhibitors; Halogenation; Insecticides; Malathion; Organophosphorus Compounds; Organothiophosphorus Compounds; Water Purification
PubMed: 32721694
DOI: 10.1016/j.chemosphere.2020.127743 -
Food Additives & Contaminants. Part A,... Mar 2022The residue changes of five pesticides in samples from different steps of rice flour production and accelerated storage were systematically investigated. Rice flour was...
The residue changes of five pesticides in samples from different steps of rice flour production and accelerated storage were systematically investigated. Rice flour was produced both by the extrusion process and the drying on roller process. The change of pesticide residues varied in different processing steps and storage time. The water adjusting step had little influence on the pesticide residues. The pesticide residues were decreased significantly in the extruding, soaking, and grinding steps with reduction from 21% to 76%. The drying step increased or decreased the pesticide residues in varying degrees through concentration due to water evaporation and thermal evaporation or thermal degradation. All the pesticide residues decreased during the accelerated storage, especially for methidathion and chlorpyrifos, neither was detected after accelerated stored for 14 days. The processing factors (PFs) for imidacloprid and isocarbophos in the drying step were greater than 1, and the others were all less than 1. The whole drying on roller process had lower PFs than the whole extrusion process, indicated that the drying on roller process had a greater effect on pesticide residues. The PFs of accelerated storage for five pesticides were all below 1. Overall, this study provides important references for monitoring pesticide residues in the processing and storage of rice flour. Moreover, the PFs obtained in this study could be useful in the dietary exposure and risk assessment of pesticides in rice flour.
Topics: Flour; Oryza; Pesticide Residues; Pesticides; Water
PubMed: 35061580
DOI: 10.1080/19440049.2021.2020910 -
Journal of Mass Spectrometry : JMS Jun 2023Gas chromatography-mass spectrometry (GC-MS) with Cold EI is based on interfacing GC and MS with supersonic molecular beams (SMBs) along with electron ionization of...
Gas chromatography-mass spectrometry (GC-MS) with Cold EI is based on interfacing GC and MS with supersonic molecular beams (SMBs) along with electron ionization of vibrationally cold sample compounds in SMB in a fly-through ion source (hence the name Cold EI). Cold EI improves all the central performance aspects of GC-MS, and in this paper, we focus on its improvement of signal-to-noise ratio (S/N) and limits of detection (LODs). We found that the harder the compound for analysis with standard EI, the greater the Cold EI gain in S/N and LOD. The lower LOD and higher S/N of Cold EI emerge from a few reasons: (a) similar ionization yield as standard EI, (b) enhanced abundance of molecular ions, (c) elimination of vacuum background noise, (d) elimination of ion source-related peak tailing and degradation, (e) ability to lower the elution temperatures via the use of high column flow rates, and (f) greater range of thermally labile and low-volatility compounds that can be analyzed. We demonstrate the superior S/N and lower LOD of Cold EI versus standard EI in a range of compounds, from the simple-to-analyze octafluoronaphthalene all the way to reserpine and an organo-metallic compound that cannot be analyzed by standard EI. These compounds include methyl stearate, cholesterol, n-C H , large polycyclic aromatic hydrocarbons, dioctyl phthalates, diundecyl phthalate, pentachlorophenol, benzidine, lambda-cyhalothrin, and methidathion. The significantly lower Cold EI LODs that can be over 1000 times better than in standard EI further result in far superior response linearity and greater measurement dynamic range.
PubMed: 37271583
DOI: 10.1002/jms.4950 -
Bioelectrochemistry (Amsterdam,... Feb 2017The interaction of pesticides with environmental factors, such as pH, may result in alterations of their physicochemical properties and should be taken into...
The interaction of pesticides with environmental factors, such as pH, may result in alterations of their physicochemical properties and should be taken into consideration in regard to their classification. This study investigates the genotoxicity of methidathion and its alkaline hydrolysis by-products in cultured human lymphocytes, using the square-wave voltammetry (square wave-adsorptive cathodic stripping voltammetry (SW-AdCSV) technique) and the cytokinesis block micronucleus assay (CBMN assay). According to the SW-AdCSV data the alkaline hydrolysis of methidathion results in two new molecules, one non-electro-active and a second electro-active which is more genotoxic than methidathion itself in cultured human lymphocytes, inducing higher micronuclei frequencies. The present study confirms the SW-AdCSV technique as a voltammetric method which can successfully simulates the electrodynamics of the cellular membrane.
Topics: Adult; Cell Membrane; Cytokinesis; Electrochemistry; Humans; Hydrolysis; Lymphocytes; Micronucleus Tests; Mutagenicity Tests; Organothiophosphorus Compounds; Young Adult
PubMed: 27607473
DOI: 10.1016/j.bioelechem.2016.08.004 -
Food Chemistry Nov 2022Electrochemiluminescent (ECL) sensors for organophosphorus pesticides (OPs) have received considerable attention, whereas complicated electrode's immobilization,...
Electrochemiluminescent (ECL) sensors for organophosphorus pesticides (OPs) have received considerable attention, whereas complicated electrode's immobilization, response to single hydrolysate and anodic emission correlated with ECL assays restrict their potential utilization. Herein, we developed a homogeneous dual-response cathodic ECL system for highly sensitive and reliable analysis of OP using CdTe QDs as emitters. CdTe QDs, emitting red light, were fabricated through a hydrothermal reaction and generated anodic and cathodic ECL emission upon stimulation of tripropyl amine and KSO, respectively. Notably, CdTe QDs-KSO showed a simultaneous response to thiol and acidic pH, and were regarded as a ECL sensor for methidathion with limit of detection of 0.016 ng/mL based on hydrolysis of acetylthiocholine into thiocholine and CHCOOH by acetylcholinesterase (AChE) and OPs' inhibition on AChE activity. This sensor also exhibited good practicability to detect methidathion in Chinese cabbage. Overall, the sensor will supply more useful information for ensuring OPs-related food safety.
Topics: Acetylcholinesterase; Biosensing Techniques; Brassica; Cadmium Compounds; China; Electrodes; Hydrogen-Ion Concentration; Organophosphorus Compounds; Pesticides; Quantum Dots; Sulfhydryl Compounds; Tellurium
PubMed: 35691064
DOI: 10.1016/j.foodchem.2022.133349 -
Environmental Analysis, Health and... Mar 2024For farmers around the world to protect crops from disturbing pests, it is common to use pesticides to ward off the growth of pests or even eliminate them. Even though...
For farmers around the world to protect crops from disturbing pests, it is common to use pesticides to ward off the growth of pests or even eliminate them. Even though pesticides are seen as a good thing for protecting crops, there is one thing that mustn't be forgotten the origin of the pesticide itself is a toxin compound that is dangerous if used irresponsibly. The main concern of this study is excessive use of pesticides may cause serious consequences to the ecosystem and environment through the accumulation of pesticide residue by irresponsible farmers. To minimize the effects of pesticide residues, the selection of the type of pesticide needs to be considered which type may not be harmful to the environment's health even though accumulation happens. Therefore, in this study, a fuzzy-based computational model assessor was built to measure the safety level of pesticides toward the environment. The fuzzy model was created with consideration of several parameters related to pesticide behaviors, its effects on beneficial organisms, and its persistence in the environment. The method used for this study includes literature reviewing, fuzzification, statistical approach, expert knowledge sharing, and quantitative analysis. The model created in this study can assist in a more accurate and realistic method of selecting better pesticide options that will be used by farmers. To ensure the validity of the model, verifying and validating the formula and pesticide result assessment were done with related literature articles. In this study, from 10 types of pesticides used as a sample, dodine, and iprodione pesticides are the best option for protecting crops with a safety level of 7.36, and abamectin, dimethoate, chorpyrifos, and methidathion are not safe options for farming use because of its potential of harming the environment.
PubMed: 38631395
DOI: 10.5620/eaht.2024003 -
Chemosphere Nov 2020Citrus is highly consumed in China and considered a major source of pesticide carrier in human diet. In this paper, pesticide residues in mandarins, tangerines and...
Citrus is highly consumed in China and considered a major source of pesticide carrier in human diet. In this paper, pesticide residues in mandarins, tangerines and oranges from China were evaluated, as well as the quality and long-term dietary risks for the Chinese consumers. Temporal variations for eight MRL non-compliant pesticides were also investigated. 106 pesticides were analyzed using QuEChERS procedure and UPLC-MS/MS, GC-MS and GC methods. Forty different pesticides were detected in 86% of the 2922 samples from 2013 to 2018. Chlorpyrifos was the most frequently detected pesticide with a detection rate of 40%. Residues of eight pesticides in 3.8% of the total samples exceeded their MRLs. The most severely excessive pesticide was bifenthrin with 283% MRL. The occurrences and exceeding rates of eight pesticides presented clear temporal variations during the six harvesting years. Isocarbophos, carbofuran and triazophos were the main risk factors threatening the citrus safety pre-2015, whereas profenofos and bifenthrin gradually became dominant after 2016, coinciding with government control measures. The index of quality for residues (IqR) levels of 88% of the samples were below 1.0, which indicated a satisfactory quality of citrus fruits in China, although 70% of the samples contained two or more residues. The cumulative chronic dietary risks were acceptable for both the Chinese general population and children and would not pose health risks. However, more strictly enforced control measures for methidathion and isocarbophos, and reduced usage of triazophos, quinalphos, profenofos and bifenthrin should be pursued to further improve the safety of citrus fruits.
Topics: Child; China; Chromatography, Liquid; Citrus; Dietary Exposure; Food Contamination; Fruit; Gas Chromatography-Mass Spectrometry; Humans; Pesticide Residues; Risk Assessment; Tandem Mass Spectrometry
PubMed: 32569958
DOI: 10.1016/j.chemosphere.2020.127381 -
Ecotoxicology and Environmental Safety Jan 2018Broad-spectrum insecticides may disrupt biological control and cause pest resurgence due to their negative impacts on natural enemies. The preservation of sustainable...
Broad-spectrum insecticides may disrupt biological control and cause pest resurgence due to their negative impacts on natural enemies. The preservation of sustainable pest control in agroecosystems requires parallel assessments of insecticide toxicity to target pests and their key natural enemies. In the present study, the leaf dipping method was used to evaluate the relative toxicity of six insecticides to the striped mealybug, Ferrisia dasylirii (Cockerell) (Hemiptera: Pseudococcidae) and its predator, Tenuisvalvae notata (Mulsant) (Coleoptera: Coccinellidae). Three neurotoxic insecticides, lambda-cyhalothrin, methidathion and thiamethoxam, caused complete mortality of both pest and predator when applied at their highest field rates. In contrast, lufenuron, pymetrozine and pyriproxyfen caused moderate mortality of third-instar mealybug nymphs, and exhibited low or no toxicity to either larvae or adults of the lady beetle. At field rates, lufenuron and pymetrozine had negligible effects on prey consumption, development or reproduction of T. notata, but adults failed to emerge from pupae when fourth instar larvae were exposed to pyriproxyfen. In addition, pyriproxyfen caused temporary sterility; T. notata females laid non-viable eggs for three days after exposure, but recovered egg fertility thereafter. Our results indicate that the three neurotoxic insecticides can potentially control F. dasylirii, but are hazardous to its natural predator. In contrast, lufenuron and pymetrozine appear compatible with T. notata, although they appear less effective against the mealybug. Although the acute toxicity of pyriproxyfen to T. notata was low, some pupal mortality and reduced egg fertility suggest that this material could impede the predator's numerical response to mealybug populations.
Topics: Animals; Brazil; Coleoptera; Environmental Pollutants; Female; Gossypium; Hemiptera; Insecticides; Larva; Nymph; Pest Control, Biological; Predatory Behavior; Pupa; Reproduction
PubMed: 29029382
DOI: 10.1016/j.ecoenv.2017.09.021 -
Food Additives & Contaminants. Part A,... Sep 2019The purpose of this study was to investigate pesticide residues in bell peppers from Shandong Province, China. A total of 299 samples were collected from 17 cities in...
The purpose of this study was to investigate pesticide residues in bell peppers from Shandong Province, China. A total of 299 samples were collected from 17 cities in 2016. The concentrations of 26 pesticide residues were determined by gas chromatography with mass spectrometry (GC-MS). The results showed that there were 25 pesticides (15 OPs, 7 PYs, 3 CBs) found in 86 bell pepper samples, and the total number of positives was 120. The total frequency was 28.76%. The detection frequency for OPs, PYs and CBs was 16.39%, 12.37% and 3.01%, respectively. The most frequently detected pesticide was bifenthrin, with the frequency of 5.02%. 5.35% of samples contained pesticide residues above the maximum residue limits (MRLs) set by China. 7.36% of samples contained more than one pesticide. The values of %ADI were below 100, while the %ARfD of carbofuran and methidathion exceeded 100 for children. The cumulative risk was highest for OPs. From the public health point of view, the levels of pesticide residues in bell peppers do not pose a serious health risk to adults, but the acute health risk to children should be paid more attention.
Topics: Adult; Capsicum; Child; China; Food Contamination; Gas Chromatography-Mass Spectrometry; Humans; Pesticide Residues; Pyrethrins; Quality Control; Risk Assessment; Solid Phase Extraction
PubMed: 31294676
DOI: 10.1080/19440049.2019.1628362 -
Journal of Chromatography. A May 2023The determination of organophosphorus pesticides in urine is useful for evaluating human exposure. In this study, a simple micro-solid-phase extraction method based on a...
Rapid and simple determination of organophosphorus pesticides in urine using polydopamine-modified monolithic spin column extraction combined with liquid chromatography-mass spectrometry.
The determination of organophosphorus pesticides in urine is useful for evaluating human exposure. In this study, a simple micro-solid-phase extraction method based on a polydopamine-modified monolithic spin column combined with liquid chromatography-mass spectrometry (LC-MS) was developed for the determination of six organophosphorus pesticides (dimethoate, dichlorvos, carbofuran, methidathion, phosalone, and chlorpyrifos) in urine samples. A methacrylate polymer monolithic support was prepared in situ in the spin column, and dopamine solution was repeatedly passed through the monolith matrix via centrifugation to generate a polydopamine layer in the polymeric network. All extraction steps were performed via centrifugation. The monolith exhibited good permeability, which enabled high-flow-rate sample loading and significantly reduced the sample pre-treatment time. The addition of polydopamine significantly improved the extraction efficiency of the monolithic spin column owing to the catechol and amine groups in dopamine, which can enhance hydrogen bonding and π-π stacking. Factors affecting the extraction, including the solution pH, centrifugation speed, and desorption solvent, were investigated to determine the optimal extraction conditions. Under the optimal conditions, the OPP detection limits were 0.02-1.32 µg/L. The relative standard deviations of the single column (n = 5) and column-to-column (n = 3) precision for the extraction method were <11%. The monolithic spin column exhibited high stability and could be used for more than 40 extraction cycles. The recoveries for spiked urine samples were 72.1-109.3% (RSDs: 1.6-7.9%). The developed method was successfully applied to the simple and rapid analysis of organophosphorus pesticides in urine samples.
Topics: Humans; Organophosphorus Compounds; Chromatography, High Pressure Liquid; Pesticides; Dopamine; Chromatography, Liquid; Polymers; Mass Spectrometry; Solid Phase Extraction
PubMed: 37028207
DOI: 10.1016/j.chroma.2023.463959