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Environmental Science and Pollution... Jul 2018The removal of five selected pesticide compounds in a brackish model groundwater solution was examined using a bench scale direct contact membrane distillation (DCMD)...
The removal of five selected pesticide compounds in a brackish model groundwater solution was examined using a bench scale direct contact membrane distillation (DCMD) system. It was found that the rejection rate of the pesticides in DCMD is mainly influenced by its properties. Compounds with low hydrophobic characteristics and low vapour pressure showed a high rejection rate (70-99%), whereas compounds with a high vapour pressure or high hydrophobicity (LogD) showed a reduced rejection (30-50%) at a water recovery of 75%. The influence of groundwater feed solution contents such as the presence of organics (humic acid) and inorganic ions (Na, Ca, Mg, Cl and SO) as well as feed temperature (40, 55 and 70 °C) on the rejection of the pesticides in DCMD operation was also evaluated. The results showed that the presence of inorganic ions and organics in the feed solution influences the pesticides rejection in DCMD operation to a minor degree. In contrast, reduced rejection of pesticides with high vapour pressure was observed. A rapid small-scale column test (RSSCT) was carried out to study the removal of any remaining substances in the permeate by adsorption onto granular activated carbon (GAC). RSSCT showed promising performance of GAC as a post-treatment option.
Topics: Adsorption; Distillation; Groundwater; Humic Substances; Hydrophobic and Hydrophilic Interactions; Ions; Membranes, Artificial; Pesticides; Temperature; Vapor Pressure; Water; Water Pollutants, Chemical; Water Purification
PubMed: 28424956
DOI: 10.1007/s11356-017-8929-1 -
Food Chemistry Sep 2017A facile, rapid sample pretreatment method was developed based on magnetic nanoparticles for multi-pesticides residue analysis of grains. Magnetite (FeO) nanoparticles...
A facile, rapid sample pretreatment method was developed based on magnetic nanoparticles for multi-pesticides residue analysis of grains. Magnetite (FeO) nanoparticles modified with 3-(N,N-diethylamino)propyltrimethoxysilane (FeO-PSA) and commercial C18 were selected as the cleanup adsorbents to remove the target interferences of the matrix, such as fatty acids and non-polar compounds. Rice was used as the representative grain sample for method optimization. The amount of FeO-PSA and C18 were systematically investigated for selecting the suitable purification conditions, and the simultaneous determination of 50 pesticides and 8 related metabolites in rice was established by liquid chromatography-tandem mass spectrometry. Under the optimal conditions, the method validation was performed including linearity, sensitivity, matrix effect, recovery and precision, which all satisfy the requirement for pesticides residue analysis. Compared to the conventional QuEChERS method with non-magnetic material as cleanup adsorbent, the present method can save 30% of the pretreatment time, giving the high throughput analysis possible.
Topics: Magnetite Nanoparticles; Pesticide Residues; Pesticides; Tandem Mass Spectrometry
PubMed: 28407931
DOI: 10.1016/j.foodchem.2017.03.082 -
PloS One 2017The UK's Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A...
The UK's Initial Operational Response (IOR) is a revised process for the medical management of mass casualties potentially contaminated with hazardous materials. A critical element of the IOR is the introduction of immediate, on-scene disrobing and decontamination of casualties to limit the adverse health effects of exposure. Ad hoc cleansing of the skin with dry absorbent materials has previously been identified as a potential means of facilitating emergency decontamination. The purpose of this study was to evaluate the in vitro oil and water absorbency of a range of materials commonly found in the domestic and clinical environments and to determine the effectiveness of a small, but representative selection of such materials in skin decontamination, using an established ex vivo model. Five contaminants were used in the study: methyl salicylate, parathion, diethyl malonate, phorate and potassium cyanide. In vitro measurements of water and oil absorbency did not correlate with ex vivo measurements of skin decontamination. When measured ex vivo, dry decontamination was consistently more effective than a standard wet decontamination method ("rinse-wipe-rinse") for removing liquid contaminants. However, dry decontamination was ineffective against particulate contamination. Collectively, these data confirm that absorbent materials such as wound dressings and tissue paper provide an effective, generic capability for emergency removal of liquid contaminants from the skin surface, but that wet decontamination should be used for non-liquid contaminants.
Topics: Animals; Decontamination; Female; Malonates; Mass Casualty Incidents; Parathion; Phorate; Potassium Cyanide; Salicylates; Skin Absorption; Swine; United Kingdom
PubMed: 28152053
DOI: 10.1371/journal.pone.0170966 -
Journal of AOAC International May 2017The present paper depicts a novel method based on magnetic SPE (MSPE) for the determination of organophosphorus pesticides (OPs) such as phorate, malathion, and...
Determination of Organophosphorous Pesticides in Environmental Water Samples Using Surface-Engineered C18 Functionalized Silica-Coated Core-Shell Magnetic Nanoparticles-Based Extraction Coupled with GC-MS/MS Analysis.
The present paper depicts a novel method based on magnetic SPE (MSPE) for the determination of organophosphorus pesticides (OPs) such as phorate, malathion, and chlorpyrifos in environmental water samples. In this study, C18 functionalized silica-coated core-shell iron oxide magnetic nanoparticles (MNPs) were used as a surface-engineered magnetic sorbent for the selective extraction of pesticides from aqueous samples, followed by GC-MS and GC-tandem MS analysis for confirmative determination of the analytes. Various important method parameters, including quantity of MNP adsorbent, volume of sample, effective time for extraction, nature of the desorbing solvent, and pH of the aqueous sample, were investigated and optimized to obtain maximum method performance. Under the optimized instrumental analysis conditions, good linearity (r2 value ≥0.994) was achieved at the concentration range of 0.5-500 μg/L. Recoveries were in the range of 79.2-96.3 and 80.4-97.5% in selective-ion monitoring and multiple reaction monitoring (MRM) modes, respectively, at the spiking concentrations of 1, 5, and 10 μg/L. MRM mode showed better sensitivity, selectivity, and low-level detection (0.5 μg/L) of analytes. The novel MSPE method is a simple, cheap, rapid, and eco-friendly method for the determination of OPs in environmental water samples.
Topics: Gas Chromatography-Mass Spectrometry; Magnetite Nanoparticles; Organophosphorus Compounds; Pesticides; Silicon Dioxide; Tandem Mass Spectrometry; Water Pollutants, Chemical
PubMed: 28084198
DOI: 10.5740/jaoacint.16-0312 -
Journal of Separation Science Oct 2016The dissipation of phorate in the sandy clay loam soil of tropical sugarcane ecosystem was studied by employing a single-step sample preparation method and gas...
Dissipation behavior of phorate and its toxic metabolites in the sandy clay loam soil of a tropical sugarcane ecosystem using a single-step sample preparation method and GC-MS.
The dissipation of phorate in the sandy clay loam soil of tropical sugarcane ecosystem was studied by employing a single-step sample preparation method and gas chromatography with mass spectrometry. The limit of quantification of the method was 0.01 μg/g. The recoveries of phorate, phorate sulfoxide, phorate sulfone, and phorate oxon were in the range 94.00-98.46% with relative standard deviations of 1.51-3.56% at three levels of fortification between 0.01 and 0.1 μg/g. The Half-life of phorate and the total residues, which include phorate, phorate sulfoxide and phorate sulfone, was 5.5 and 19.8 days, respectively at the recommended dose of insecticide. Phorate rapidly oxidized into its sulfoxide metabolite in the sandy clay loam soil. Phorate sulfoxide alone accounted for more than 20% of the total residues within 2 h post-application and it was more than 50% on the fifth day after treatment irrespective of the doses applied. Phorate sulfoxide and phorate sulfone reached below the detectable level on 105 and 135 days after treatment, respectively as against 45 days after treatment for phorate residues at the recommended dose. Thus, the reasonably prolonged efficacy of phorate against soil pests may be attributed to longer persistence of its more toxic sulfoxide and sulfone metabolites.
Topics: Aluminum Silicates; Clay; Ecosystem; Gas Chromatography-Mass Spectrometry; Half-Life; Insecticides; Pesticide Residues; Phorate; Saccharum; Soil; Soil Pollutants
PubMed: 27546010
DOI: 10.1002/jssc.201600560 -
Pest Management Science Feb 2017Organophosphate insecticides can inhibit specific cytochrome P450 enzymes involved in metabolic herbicide resistance mechanisms, leading to synergistic interactions...
BACKGROUND
Organophosphate insecticides can inhibit specific cytochrome P450 enzymes involved in metabolic herbicide resistance mechanisms, leading to synergistic interactions between the insecticide and the herbicide. In this study we report synergistic versus antagonistic interactions between the organophosphate insecticide phorate and five different herbicides observed in a population of multiple herbicide-resistant Lolium rigidum.
RESULTS
Phorate synergised with three different herbicide modes of action, enhancing the activity of the ALS inhibitor chlorsulfuron (60% LD reduction), the VLCFAE inhibitor pyroxasulfone (45% LD reduction) and the mitosis inhibitor trifluralin (70% LD reduction). Conversely, phorate antagonised the two thiocarbamate herbicides prosulfocarb and triallate with a 12-fold LD increase.
CONCLUSION
We report the selective reversal of P450-mediated metabolic multiple resistance to chlorsulfuron and trifluralin in the grass weed L. rigidum by synergistic interaction with the insecticide phorate, and discuss the putative mechanistic basis. This research should encourage diversity in herbicide use patterns for weed control as part of a long-term integrated management effort to reduce the risk of selection of metabolism-based multiple herbicide resistance in L. rigidum. © 2016 Society of Chemical Industry.
Topics: Cholinesterase Inhibitors; Cytochrome P-450 Enzyme System; Herbicide Resistance; Herbicides; Insecticides; Lolium; Pesticide Synergists; Phorate
PubMed: 27643926
DOI: 10.1002/ps.4441 -
Pest Management Science Jan 2017Rice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource-efficient direct-seeded rice...
BACKGROUND
Rice is a major field crop of paramount importance for global food security. However, the increased adoption of more profitable and resource-efficient direct-seeded rice (DSR) systems has contributed to greater weed infestations, including weedy rice, which has become a severe problem in several Asian regions. In this study we have developed a conceptually novel method to protect rice plants at high doses of clomazone and triallate.
RESULTS
The insecticide phorate applied to rice seeds provided a substantial level of protection against the herbicides clomazone or triallate. A quantity of 15 kg phorate ha significantly increased the LD values, which were more than twofold greater than for rice plants treated only with clomazone. A quantity of 20 kg phorate ha in combination with 2000 g triallate ha safened rice plants (80% survival) with LD >3.4-fold greater than in phorate-untreated rice. Weed control efficacy was not lowered by the presence of phorate-treated rice seeds.
CONCLUSION
Weedy rice is one of the most damaging global weeds and a major threat to DSR systems. In this study we have developed a proof-of-concept method to allow selective weedy rice control in rice crops. We call for herbicide discovery programmes and research to identify candidate safener and herbicide combinations to achieve selective herbicide control of weedy rice and alleviate weed infestations in global rice crops. © 2016 Society of Chemical Industry.
Topics: Crops, Agricultural; Herbicides; Isoxazoles; Oryza; Oxazolidinones; Plant Weeds; Seeds; Triallate; Weed Control
PubMed: 27484802
DOI: 10.1002/ps.4411 -
The Journal of Toxicological Sciences 2016Anticholinesterases, such as organophosphorus pesticides and warfare nerve agents, present a significant health threat. Onset of symptoms after exposure can be rapid,... (Comparative Study)
Comparative Study
Anticholinesterases, such as organophosphorus pesticides and warfare nerve agents, present a significant health threat. Onset of symptoms after exposure can be rapid, requiring quick-acting, efficacious therapy to mitigate the effects. The goal of the current study was to identify the safest antidote with the highest therapeutic index (TI = oxime 24-hr LD50/oxime ED50) from a panel of four oximes deemed most efficacious in a previous study. The oximes tested were pralidoxime chloride (2-PAM Cl), MMB4 DMS, HLö-7 DMS, and obidoxime Cl2. The 24-hr median lethal dose (LD50) for the four by intramuscular (IM) injection and the median effective dose (ED50) were determined. In the ED50 study, male guinea pigs clipped of hair received 2x LD50 topical challenges of undiluted Russian VX (VR), VX, or phorate oxon (PHO) and, at the onset of cholinergic signs, IM therapy of atropine (0.4 mg/kg) and varying levels of oxime. Survival was assessed at 3 hr after onset clinical signs. The 3-hr 90th percentile dose (ED90) for each oxime was compared to the guinea pig pre-hospital human-equivalent dose of 2-PAM Cl, 149 µmol/kg. The TI was calculated for each OP/oxime combination. Against VR, MMB4 DMS had a higher TI than HLö-7 DMS, whereas 2-PAM Cl and obidoxime Cl2 were ineffective. Against VX, MMB4 DMS > HLö-7 DMS > 2-PAM Cl > obidoxime Cl2. Against PHO, all performed better than 2-PAM Cl. MMB4 DMS was the most effective oxime as it was the only oxime with ED90 < 149 µmol/kg against all three topical OPs tested.
Topics: Animals; Antidotes; Atropine; Chemical Warfare Agents; Cholinesterase Inhibitors; Cholinesterase Reactivators; Dose-Response Relationship, Drug; Guinea Pigs; Lethal Dose 50; Male; Muscarinic Antagonists; Obidoxime Chloride; Organophosphate Poisoning; Organothiophosphorus Compounds; Oximes; Pesticides; Pralidoxime Compounds; Pyridinium Compounds; Time Factors
PubMed: 27432237
DOI: 10.2131/jts.41.511 -
Talanta Aug 2016In this work, the metal-organic frameworks (MOFs), MIL-101-Cr-NH2 was synthesized via a direct hydrothermal method, and a polydimethylsiloxane (PDMS)/MIL-101-Cr-NH2...
Polydimethylsiloxane/metal-organic frameworks coated stir bar sorptive extraction coupled to gas chromatography-flame photometric detection for the determination of organophosphorus pesticides in environmental water samples.
In this work, the metal-organic frameworks (MOFs), MIL-101-Cr-NH2 was synthesized via a direct hydrothermal method, and a polydimethylsiloxane (PDMS)/MIL-101-Cr-NH2 coated stir bar was prepared by sol-gel technique. Good reproducibility was obtained for the preparation of PDMS/MIL-101-Cr-NH2 coated stir bar with the relative standard deviations (RSDs) ranging from 3.7 to 5.2% (n=7) in one batch, and from 5.4 to 9.2% (n=7) among different batches. With the high surface area and rich benzene ring structure of MIL-101-Cr-NH2, the prepared PDMS/MIL-101-Cr-NH2 coated stir bar presented higher extraction efficiency for target organophosphorus pesticides (OPPs, including phorate, diazinon, malathion, fenthion, quinalphos and ethion) over PDMS coated stir bar. Based on it, a new method of PDMS/MIL-101-Cr-NH2 coated stir bar sorptive extraction (SBSE) coupled to gas chromatography-flame photometric detection (GC-FPD) was proposed for the determination of six OPPs in environmental water samples. The operation parameters affecting the extraction efficiency of SBSE, including extraction time, stirring rate, desorption time and ionic strength, were investigated. Under the optimal conditions, the limits of detection (S/N=3) were found to be in the range of 0.043-0.085μgL(-1) for the six target OPPs, and the linear range was 0.5-100μgL(-1) for malathion and 0.2-100μgL(-1) for other five OPPs. The RSDs of the proposed method evaluated at 1µgL(-1) for each OPP were in the range of 5.9-8.7% (intra-day, n=7) and 6.1-10.7% (inter-day, n=5), respectively. The enrichment factors were varied from 110 to 151-fold (theoretical enrichment factor was 200-fold). The proposed method was applied to the analysis of OPPs in East Lake and pond water samples with recoveries in the range of 89.3-115% and 80.0-113% for the spiked East Lake and pond water samples, respectively.
Topics: Chemical Fractionation; Chromatography, Gas; Chromium; Coordination Complexes; Dimethylpolysiloxanes; Environmental Monitoring; Lakes; Limit of Detection; Metal-Organic Frameworks; Organophosphorus Compounds; Pesticides; Water Pollutants, Chemical
PubMed: 27260444
DOI: 10.1016/j.talanta.2016.05.001 -
Human & Experimental Toxicology May 2017The present study aims to investigate the protective effect of quercetin against the joint toxic action induced by the mixture of four organophosphate pesticides...
The present study aims to investigate the protective effect of quercetin against the joint toxic action induced by the mixture of four organophosphate pesticides (mixture-OPs) (dimethoate, acephate, dichlorvos, and phorate) at their corresponding no observed adverse effect level (NOAEL) using metabonomics. Rats were randomly divided into control, quercetin-treated, mixture-OPs-treated, and quercetin plus mixture-OPs-treated groups. Mixture-OPs and quercetin were given to the rats daily through drinking water and intragastric administration, respectively, for 90 days. The metabonomic profiles of rat urine were analyzed using ultra-performance liquid chromatography-mass spectrometry (UPLC/MS). The 14 metabolites significantly changed in the treatment groups compared with the control group, including the biomarkers of OPs exposure (dimethylphosphate, dimethyldithiophosphate, diethylphosphate) and the metabolites of quercetin (quercetin and isorhamnetina). The intensities of gentisic acid, creatinine, suberic acid, hippuric acid, uric acid, and citric acid significantly decreased, whereas the intensities of 7-methylguanine, estrone sulfate, and cholic acid significantly increased, in the mixture-OPs-treated group compared with the control group ( p < 0.01). The variation tendency of the aforementioned metabolites was significantly ameliorated in the high-dose quercetin (50 mg/(kg bw day)) plus mixture-OPs-treated group compared with the mixture-OPs-treated group ( p < 0.05). However, the intensities of these metabolites in the high-dose quercetin plus mixture-OPs-treated group were still significantly different from those of the control group ( p < 0.05). Results indicated that high dose of quercetin elicits a partial protective effect on the toxicity induced by mixture-OPs, including fatty acid and energy metabolism, antioxidant defense system, DNA damage, and liver and kidney function.
Topics: Animals; Biomarkers; Comet Assay; DNA Damage; Insecticides; Lymphocytes; Male; Metabolomics; Organophosphates; Protective Agents; Quercetin; Rats; Rats, Wistar
PubMed: 27251765
DOI: 10.1177/0960327116652460