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Chemosphere Dec 2023Soil moisture, organic matter, and soil microbes are the key considering factors that control the persistence, degradation, and transformation of applied pesticides...
Soil moisture, organic matter, and soil microbes are the key considering factors that control the persistence, degradation, and transformation of applied pesticides under varied soil conditions. In this study, underlying influence of these factors was assessed through the fates and metabolic transformation of two non-ionic pesticides (e.g., Phorate and Terbufos) in soils. Concisely, two distinct experiments including a customized batch equilibrium (sorption study), and a lab incubation trial (degradation study) were performed, following the OECD guidelines. As per study findings, biochar (BC) amendment was found to be the most influential factors during sorption study, particularly, 1% BC amendment contributed to achieve the best results. In addition, the non-linearity of sorption isotherm (1/n < 1.0) was revealed through Freundlich isotherm, indicating the strong adsorption of studied pesticides onto the soils. On the other hand, during degradation study, soil moisture initiates the enhanced degradation of parent pesticides and subsequent metabolism. In the presence of 40% water holding capacity (WHC), 1% BC amendment enhances the metabolic transformation, while HO treatment could hinder the process. Additionally, the half-life degradation (t) of phorate and terbufos was controlled by biochar amendment, moisture, and soil sterilization, respectively. Finally, BC can accelerate the metabolic transformation, whereas, phorate underwent a metabolic change into sulfoxide and sulfone while terbufos turned into solely sulfoxide. This pioneering study gathered crucial data for understanding the persistence and metabolic transition of non-ionic pesticides in soils and their patterns of degradation.
Topics: Pesticides; Soil; Phorate; Hydrogen Peroxide; Charcoal; Sulfoxides; Soil Pollutants; Adsorption
PubMed: 37844696
DOI: 10.1016/j.chemosphere.2023.140458 -
RSC Advances Sep 2021Understanding the interactions between nanoparticles and organophosphates is the key to developing cost-effective colorimetric pesticide detection. We have studied the...
Understanding the interactions between nanoparticles and organophosphates is the key to developing cost-effective colorimetric pesticide detection. We have studied the interaction between three different organophosphates containing the P[double bond, length as m-dash]S group and borohydride stabilized silver nanoparticles. Three different organophosphates, namely phorate, chlorpyrifos, and malathion, have been used. The colorimetric changes are corroborated with UV-visible absorption studies along with the change in particle size and zeta potential. This effect persists in the presence of NaCl solution also. The chlorpyrifos and malathion do not show significant interactions with uncapped nanoparticles over time, while phorate undergoes degradation due to the scission of the S-CH linkage. A reaction mechanism, wherein a silver and sulfur (Ag→S) complex is formed, which is in agreement with Raman spectroscopic studies is proposed. The orientations of phorate near Ag nanoparticles are discussed from the adsorption energy calculation using density functional theory.
PubMed: 35495484
DOI: 10.1039/d1ra06911j -
Environmental Research Oct 2020Exposure to Plant Protection Products, PPPs, (fungicides, herbicides and insecticides) is a significant stressor for bees and other pollinators, and has recently been...
Exposure to Plant Protection Products, PPPs, (fungicides, herbicides and insecticides) is a significant stressor for bees and other pollinators, and has recently been the focus of intensive debate and research. Specifically, exposure through contaminated pollen and nectar is considered pivotal, as it presents the highest risk of PPP exposure across all bee species. However, the actual risk that multiple PPP residues might pose to non-target species is difficult to assess due to the lack of clear evidence of their actual concentrations. To consolidate the existing knowledge of field-realistic residues detected in pollen and nectar directly collected from plants, we performed a systematic literature review of studies over the past 50 years (1968-2018). We found that pollen was the matrix most frequently evaluated and, of the compounds investigated, the majority were detected in pollen samples. Although the overall most studied category of PPPs were the neonicotinoid insecticides, the compounds with the highest median concentrations of residues in pollen were: the broad spectrum carbamate carbofuran (1400 ng/g), the fungicide and nematicide iprodione (524 ng/g), and the organophosphate insecticide dimethoate (500 ng/g). In nectar, the highest median concentration of PPP residues detected were dimethoate (1595 ng/g), chlorothalonil (76 ng/g), and the insecticide phorate (53.5 ng/g). Strong positive correlation was observed between neonicotinoid residues in pollen and nectar of cultivated plant species. The maximum concentrations of several compounds detected in nectar and pollen were estimated to exceed the LD for honey bees, bumble bees and four solitary bee species, by several orders of magnitude. However, there is a paucity of information for the biggest part of the world and there is an urgent need to expand the range of compounds evaluated in PPP studies.
Topics: Animals; Bees; Insecticides; Neonicotinoids; Pesticide Residues; Plant Nectar; Pollen; Pollination
PubMed: 32795671
DOI: 10.1016/j.envres.2020.109873 -
Bulletin of Environmental Contamination... Nov 2015Phorate, an organophosphorus insecticide, has been found effective for the control of various insect pests. However, it is an extremely hazardous insecticide and causes...
Phorate, an organophosphorus insecticide, has been found effective for the control of various insect pests. However, it is an extremely hazardous insecticide and causes a potential threat to ecosystem. Bioremediation is a promising approach to degrade the pesticide from the soil. The screening of soil from sugarcane fields resulted in identification of Brevibacterium frigoritolerans, a microorganism with potential for phorate bioremediation was determined. B. frigoritolerans strain Imbl 2.1 resulted in the active metabolization of phorate by between 89.81% and 92.32% from soils amended with phorate at different levels (100, 200, 300 mg kg(-1) soil). But in case of control soil, 33.76%-40.92% degradation were observed. Among metabolites, sulfone was found as the main metabolite followed by sulfoxide. Total phorate residues were not found to follow the first order kinetics. This demonstrated that B. frigoritolerans has potential for bioremediation of phorate both in liquid cultures and agricultural soils.
Topics: Agriculture; Bacillus; Biodegradation, Environmental; Brevibacterium; Insecticides; Kinetics; Phorate; Soil; Soil Microbiology; Soil Pollutants
PubMed: 26205232
DOI: 10.1007/s00128-015-1617-2 -
Nanomaterials (Basel, Switzerland) Jun 2024Extensive use of pesticides in agricultural production has been causing serious health threats to humans and animals. Among them, phorate is a highly toxic...
Extensive use of pesticides in agricultural production has been causing serious health threats to humans and animals. Among them, phorate is a highly toxic organophosphorus insecticide that has been widely used in planting. Due to its harmful effects on human and animal health, it has been restricted for use in many countries. Analytical methods for the rapid and sensitive detection of phorate residues in agricultural products are urgently needed. In this study, a new method was developed by combining surface-enhanced Raman spectroscopy (SERS) and immunochromatography assay (ICA). Hybrid magnetic FeO@Au@DTNB-Ab nanoprobes were prepared by modifying and growing Au nanoseeds on an FeO core. SERS activity of the nanoprobe was optimized by adjusting the concentration of the Au precursor. A rapid and sensitive assay was established by replacing the traditional colloidal gold-based ICA with hybrid SERS nanoprobes for SERS-ICA. After optimizing parameters including coating antibody concentrations and the composition and pH of the buffer solution, the limit of detection (LOD) for phorate could reach 1 ng/mL, with a linear range of 5~100 ng/mL. This LOD is remarkably lower than the maximum residue limit in vegetables and fruits set by the Chinese government. The feasibility of this method was further examined by conducting a spiking test with celery as the real sample. The result demonstrated that this method could serve as a promising platform for rapid and sensitive detection of phorate in agricultural products.
PubMed: 38921922
DOI: 10.3390/nano14121046 -
Molecules (Basel, Switzerland) Jan 2022With the internationalization of traditional Chinese medicines (TCMs) and the increasing use of herbal medicines around the world, there are concerns over their safety....
With the internationalization of traditional Chinese medicines (TCMs) and the increasing use of herbal medicines around the world, there are concerns over their safety. In recent years, there have been some sporadic reports of pesticide residues in Chuanxiong Rhizoma (CX), although the lack of systematic and comprehensive analyses of pesticide residues and evaluations of toxicological risks in human health has increased the uncertainty of the potential effects of pesticides exposure in humans. This study aimed to clarify the status of pesticide residues and to determine the health risks of pesticide residues in CX. The findings of this study revealed that 99 batches of CX samples contained pesticide residues ranging from 0.05 to 3013.17 μg/kg. Here, 6-22 kinds of pesticides were detected in each sample. Prometryn, carbendazim, dimethomorph, chlorpyrifos, chlorantraniliprole, pyraclostrobin, and paclobutrazol were the most frequently detected pesticides, with detection rates of 68.69-100%. Insecticides and fungicides accounted for 43.23% and 37.84% of the total pesticides detected, respectively. Here, 86.87% of the pesticide content levels were lower than 50 μg/kg, and a small number of samples contained carbofuran, dimethoate, and isofenphos-methyl exceeding the maximum residue levels (MRLs). A risk assessment based on the hazard quotient/hazard index (HQ/HI) approach revealed that the short-term, long-term, and cumulative risks of pesticide residues in CX are well below the levels that may pose a health risk. Worryingly, six banned pesticides (carbofuran, phorate sulfone, phorate-sulfoxide, isofenphos-methyl, terbufos-sulfone, and terbufoxon sulfoxide) were detected. This study has improved our understanding of the potential exposure risk of pesticide multi-residues in CX. The results of the study will have a positive impact on improving the quality and safety of CX and the development of MRLs for pesticide residues.
Topics: Chromatography, Gas; Chromatography, Liquid; Drugs, Chinese Herbal; Food Contamination; Humans; Medicine, Chinese Traditional; Pesticide Residues; Risk Assessment; Tandem Mass Spectrometry
PubMed: 35163887
DOI: 10.3390/molecules27030622 -
Analytica Chimica Acta May 2021Herein, we originally aimed at developing fluorescence anisotropy biosensor platforms devoted to the homogeneous-phase detection of isocarbophos and phorate pesticides...
Herein, we originally aimed at developing fluorescence anisotropy biosensor platforms devoted to the homogeneous-phase detection of isocarbophos and phorate pesticides by using previously isolated DNA aptamers. To achieve this, two reporting approaches displaying very high generalizability features were implemented, based on either the complementary strand or the SYBR green intercalator displacement strategies. Unfortunately, none of the transduction methods led to phorate-dependent signals. Only the SYBR green displacement method provided a small output in the presence of isocarbophos, but at an analyte concentration greater than 100 μM. In order to identify the origin of such data, isothermal titration calorimetry (ITC) experiments were subsequently performed. It was shown that aptamers bind neither isocarbophos nor phorate in free solution with the claimed micromolar dissociation constants. This work puts forward some doubts about the previously described aptasensors that rely on the use of these functional DNA molecules. It also highlights the need to carefully investigate the binding capabilities of aptamers after their isolation and to include appropriate control experiments with scrambled or mutated oligonucleotides.
Topics: Aptamers, Nucleotide; Biosensing Techniques; DNA; Dissociative Disorders; Humans; Pesticides
PubMed: 33867041
DOI: 10.1016/j.aca.2021.338382 -
Journal of Economic Entomology May 2018Peanut growers use a combination of tactics to manage spotted wilt disease caused by thrips-transmitted Tomato spotted wilt virus (TSWV). They include planting...
Evaluation of Alternatives to an Organophosphate Insecticide with Selected Cultural Practices: Effects on Thrips, Frankliniella fusca, and Incidence of Spotted Wilt in Peanut Farmscapes.
Peanut growers use a combination of tactics to manage spotted wilt disease caused by thrips-transmitted Tomato spotted wilt virus (TSWV). They include planting TSWV-resistant cultivars, application of insecticides, and various cultural practices. Two commonly used insecticides against thrips are aldicarb and phorate. Both insecticides exhibit broad-spectrum toxicity. Recent research has led to the identification of potential alternatives to aldicarb and phorate. In this study, along with reduced-risk, alternative insecticides, we evaluated the effect of conventional versus strip tillage; single versus twin row seeding pattern; and 13 seed/m versus 20 seed/m on thips density, feeding injury, and spotted wilt incidence. Three field trials were conducted in Georgia in 2012 and 2013. Thrips counts, thrips feeding injuriy, and incidence of spotted wilt were less under strip tillage than under conventional tillage. Reduced feeding injury from thrips was observed on twin-row plots compared with single-row plots. Thrips counts, thrips feeding injury, and incidence of spotted wilt did not vary by seeding rate. Yield from twin-row plots was greater than yield from single-row plots only in 2012. Yield was not affected by other cultural practices. Alternative insecticides, including imidacloprid and spinetoram, were as effective as phorate in suppressing thrips and reducing incidence of spotted wilt in conjunction with cultural practices. Results suggest that cultural practices and reduced-risk insecticides (alternatives to aldicarb and phorate) can effectively suppress thrips and incidence of spotted wilt in peanut.
Topics: Animals; Arachis; Crop Production; Georgia; Insect Control; Insecticides; Macrolides; Neonicotinoids; Plant Diseases; Thysanoptera; Tospovirus
PubMed: 29635299
DOI: 10.1093/jee/toy079 -
Fa Yi Xue Za Zhi Jun 2018To investigate the maximum allowable deviation of retention time (RT) or relative retention time (RRT) between the common poisons (drugs) and standard...
OBJECTIVES
To investigate the maximum allowable deviation of retention time (RT) or relative retention time (RRT) between the common poisons (drugs) and standard solvent by gas chromatography-mass spectrometry (GC-MS).
METHODS
After pretreatment with liquid-liquid extraction, four common poisons (drugs)-dichlorvos, phorate, diazepam and estazolam-were detected by full scan mode GC-MS. RT and RRT were analyzed according to combined uncertainty and expanded uncertainty.
RESULTS
The expanded uncertainty of RT and RRT were 6.0×10-14.1×10 and 2.5×10-5.9×10 (=3), respectively. The RT of poisons (drugs) was relatively stable in blood samples with different mass concentrations. Among dichlorvos, phorate, diazepam and estazolam, the absolute deviation and relative deviation of RT were ≤0.03 min and ≤0.4%, respectively, and those of RRT were ≤0.003 min and ≤0.3%, respectively.
CONCLUSIONS
The maximum allowable deviations of RT and RRT for common poisons (drugs) in blood samples are recommended to be ±0.05 min and ±0.5%.
Topics: Gas Chromatography-Mass Spectrometry; Poisons
PubMed: 30896095
DOI: 10.12116/j.issn.1004-5619.2018.06.004 -
Analytica Chimica Acta Sep 2015A nanomaterials-based novel molecular beacon has attracted growing attentions in fluorescent assays as many nanomaterials possess excellent quenching efficiency. In this...
A nanomaterials-based novel molecular beacon has attracted growing attentions in fluorescent assays as many nanomaterials possess excellent quenching efficiency. In this work, a gold-based nanobeacon probe was established to detect organophosphorus pesticides for the first time. The constructed gold-based nanobeacon acted as a signal indicator and could display the decreasing of the intensity in the presence of targets, which competitively bound to single strand DNA. To achieve a high sensitive probe, some parameters including solution pH, temperature and reaction time were investigated and optimized. The gold-based nanobeacon probe assay was proved to be rapid and sensitive to achieve a detection limit of 0.035 μM for isocarbophos, 0.134 μM for profenofos, 0.384 μM for phorate and 2.35 μM for omethoate, respectively. The prepared nanobeacon effectively reduced the background and improved the detection sensitivity and selectivity. The probe is stable, easy to operate and does not need sophisticated instruments. These features makes the probe feasible for screening trace organophosphorus pesticides in real samples.
Topics: Aptamers, Nucleotide; DNA, Single-Stranded; Fluorescence Resonance Energy Transfer; Fluorescent Dyes; Gold; Limit of Detection; Metal Nanoparticles; Organophosphorus Compounds; Pesticides
PubMed: 26388389
DOI: 10.1016/j.aca.2015.08.012