Search

Development of selective, ultra-sensitive, rapid and facile methods for the detection of chemical residues of toxic pesticides and hazardous chemicals are quite important in food safety, environmental monitoring and safeguarding public health. Herein, we presented a fluorescent turn-on aptasensor based on sulphur-doped graphene quantum dot (S-GQD) utilizing specific recognition and binding property of aptamer for the ultra-sensitive and selective detection of omethoate (OM) which is a systemic organophosphorus pesticide. The detection method is based on tuning aggregation-disaggregation mechanism of S-GQD by way of conformational alteration of the recognition probe. Fluorescence ‘turn-on’ process includes aggregation-induced quenching of S-GQD with aptamer via S-GQD-aptamer complex formation and its subsequent fluorescence recovery with the addition of OM by structural switching of S-GQD-aptamer complex to aptamer-omethoate complex. The reported ‘switch-on’ aptasensor has exhibited a low limit of detection of 0.001 ppm with high selectivity for OM over other pesticides.

This study investigated the levels of highly toxic pesticides (HTPs) in 6554 vegetable and fruit samples from 31 regions of China, along with the associated risk of dietary exposure for the population between 2014 and 2017. 18 HTPs were detected in 325 (4.96%) samples, and the levels of HTPs in 103 (1.57%) samples were found to be higher than the maximum residue limits (MRLs) of China. The rate of detection of HTPs in six types of vegetables and fruits, in a decreasing order, was found to be as follows: eggplant (8.84%) >grape (5.58%) >tomato (5.43%) >cucumber (5.43%) >pear (3.12%) >apple (2.30%). The level of contamination of HTPs was found to be higher in vegetables compared with fruits. The vegetable and fruit samples with the highest percentages of HTPs exceeding MRLs were found in eggplants from Guangxi (20%) and grapes from Inner Mongolia (12.5%), respectively. Both, the average target hazard quotient (THQ) of a single highly toxic pesticide (HTP) and the average hazard index (HI) of the mixture of HTPs for adults and children from vegetables and fruits from the 31 regions were found to be less than one. Omethoate, carbofuran, ethoprophos, triazophos, and phorate were identified as the major contributors to the average HI for vegetables, and carbofuran, ethoprophos, omethoate, phorate, and phosphamidon were identified as the primary contributors to the average HI for fruits. The results of this study revealed that HTPs in vegetables and fruits did not cause any significant chronic risk of dietary exposure. The detection of HTPs exceeding MRLs in some of the samples implied that appropriate management guidelines for HTPs should be implemented to protect the health of the consumers.

Insect pests are primarily controlled by insecticides. However, the sensitivity decreases and insecticide resistance is problematic for the effective management of agriculturally important insects, including Metopolophium dirhodum, which is an aphid that commonly feeds on cereals. The insecticide sensitivity status and potential resistance of M. dirhodum field populations remain relatively unknown. In this study, the susceptibility of 19 M. dirhodum populations from seven provinces in Northern China to neonicotinoids, pyrethroids, organophosphates, and a macrolide (abamectin) was determined in 2017–2019. The results indicated that two populations were highly resistant to thiamethoxam, with a relative resistance ratio (RLR) of 134.03 and 103.03, whereas one population was highly resistant to beta-cypermethrin (RLR of 121.42). On the basis of the RLR, the tested M. dirhodum populations ranging from susceptible to showing moderate levels of resistance to imidacloprid (RLR of 1.50 to 57.29), omethoate (RLR of 1.07 to 18.73), and abamectin (RLR of 1.10 to 25.89), but they were ranging from susceptible to showing tolerance or low levels of resistance to bifenthrin (RLR of 1.14 to 6.02) and chlorpyrifos (RLR of 1.11 to 7.59). Furthermore, a pair-wise correlation analysis revealed a significant correlation between the median lethal concentrations (LC50) for beta-cypermethrin and thiamethoxam, reflecting the cross-resistance between these two insecticides. The data obtained in our study provide timely information about aphid insecticide sensitivity, which may be used to delay the evolution of M. dirhodum insecticide resistance in Northern China.

This study investigated the effect of interleukin (IL)-10 on the expression of OX62, MHC-II and CD86 in bone marrow dendritic cells (DCs) in rats with organophosphorus poisoning. Sixty adult SD rats were randomly divided into normal control group (group A) (20 rats), 20 rats with organophosphorus pesticide poisoning (group B), 20 rats with organophosphorus poisoning, and IL-10 treated (group C). Group A was not treated with special treatment. Group B was treated with 4% omethoate by gavage to establish the model of organophosphate poisoning. Group C was treated with omethoate to establish the model of organophosphate poisoning, then the rats were given intraperitoneal injection of IL-10 for 3 continuous days. Rats were sacrificed after 3 days, bone marrow lymphocytes were extracted, DCs were collected and cultured for 7 days, the expression of DC surface antigen OX62, MHC-II, CD86 and related proteins was detected by flow cytometry and western blotting after cell maturation. The expression of DC surface antigen and corresponding protein increased in group B, and decreased in group C, the difference was statistically significant (P

A double-film screening card, composed of an enzyme (acetylcholinesterase, AChE) and its substrate (indoxyl acetate) films, was developed for simple and rapid screening of organophosphate and carbamate pesticide residues. On the card, indoxyl acetate is decomposed by AChE to produce a blue-green compound. Compared with the speed of inhibition of AChE activity by pesticides, The color developing speed is relatively slow. When a sample solution with pesticides is dropped in the test window, this reaction of AChE is efficiently and rapidly inhibited to a degree depending on the level of pesticide. Any remaining active AChE would hydrolyze indoxyl acetate to show color. Qualitative and quantitative detection of pesticide residues could be achieved based on the color intensity. The selected suitable carrier films containing the enzyme and substrate were hydrophilic materials that were capable of adsorbing and releasing the full doze of enzyme or substrate. The optimum materials for containing AChE and indoxyl acetate on the card were glass fiber RB65 and polyester fiber VL78, respectively. The optimum quantities of AChE and indoxyl acetate per film in the test window were 15 μL of 3500 U/mL and 10 μL of 100 mM, respectively. The maximum color intensity was reached at room temperature in 15 min. The limits of detection were up to 0.05 μg/mL for phoxim, 0.1 μg/mL for acephate, 0.5 μg/mL for malathion, 0.5 μg/mL for omethoate, 0.04 μg/mL for carbofuran and 0.09 μg/mL for aldicarb. The card showed good reproducibility and high sensitivity when applied to real food samples.

Increasing studies suggest that insecticides are one of the plant stress elements that affect plant growth and productivity by interfering with cell metabolic and biochemical activities. He...

// Xiaoran Duan 1 , Yongli Yang 2 , Sihua Wang 3 , Xiaolei Feng 1 , Tuanwei Wang 1 , Pengpeng Wang 1 , Suxiang Liu 4 , Lei Li 4 , Guoyu Li 4 , Wu Yao 1 , Liuxin Cui 1 and Wei Wang 1 1 Department of Occupational and Environmental Health, College of Public Health, Zhengzhou University, Zhengzhou, China 2 Department of Epidemiology and Biostatistics, College of Public Health, Zhengzhou University, Zhengzhou, China 3 Department of Occupational Health, Henan Institute for Occupational Medicine, Zhengzhou, China 4 Clinical Department, Zhengzhou Institute of Occupational Health, Zhengzhou, China Correspondence to: Wei Wang, email: ww375@126.com Yongli Yang, email: ylyang377@126.com Keywords: omethoate, telomere, polymorphism, metabolic enzymes Received: June 27, 2017 Accepted: August 29, 2017 Published: September 18, 2017 ABSTRACT Purpose: This study aimed to explore the effects of genetic polymorphisms in metabolic enzymes on relative telomere length changes and explore the mechanism of canceration induced by omethoate. Materials and Methods: 180 long-term omethoate-exposed workers and 115 healthy controls were recruited. Real-time PCR method was applied to determine the relative telomere length in peripheral blood leukocytes DNA, and Six polymorphic loci of GSTT1 (+/−), GSTM1 (+/−), GSTP1 rs1695, CYP2E1 rs6413432, CYP2E1 rs3813867 and PON2 rs12026 were detected by polymerase chain reaction and restriction fragment length polymorphism method; Multiple linear regression was conducted to explore the effects of omethoate exposure and genetic polymorphisms on the telomere length. Results: The relative telomere lengths in the control group (0.94 [0.76, 1.32]) were significantly shorter than that in the exposure group (1.50 [1.11, 2.57]) ( Z = 7.910, P < 0.001). Univariate analysis showed that the relative telomere lengths of the GSTM1 -deletion individuals were significantly longer than that of the non - deletion genotype in the control group ( Z = 2.911, P = 0.004), and the relative telomere lengths of GSTP1 rs1695 polymorphism locus (GG+AG) genotype individuals were longer than that of AA genotype in the exposure group. The difference was statistically significant ( Z = 2.262, P = 0.024). Multivariate analysis found that pesticide-exposure ( b = 0.524, P < 0.001) and GSTM1 polymorphism ( b = −0.136, P = 0.029) had an impact on telomere length. Conclusions: The relative telomere lengths of omethoate-exposure workers were longer than that in the control population. Also GSTM1 genetic polymorphism may influence the changes of the telomere length induced by omethoate.

Carboxylesterases (CarEs) play an important role in detoxifying insecticides in insects. Over-expression and structural modification of CarEs have been implicated in the development of organophosphate (OP) insecticide resistance in insects. A previous study identified four nonsynonymous mutations (resulting in four amino acid residue substitutions) in the open reading frame of the carboxylesterase gene of resistant cotton aphids compared to the omethoate susceptible strain, which has possibly influenced the development of resistance to omethoate (a systemic OP insecticide). The current study further characterized the function of these mutations, both alone and in combination, in the hydrolysis of OP insecticides. The metabolism results suggest that the combination of four mutations, mainly existing in the laboratory-selected OP-resistant cotton aphid population, increased the OP hydrolase activity (approximately twofold) at the cost of detectable carboxylesterase activity. The functional studies of single or multiple mutations suggest the positive effect of H104R, A128V and T333P on the acquisition of OP hydrolase activity, especially the combination of H104R with A128V or T333P. K484R substitution decreased both the OP hydrolase activity and the CarE activity, indicating that this mutation primarily drives the negative effect on the acquisition of OP hydrolase activity amongst these four mutations in the resistant strain. The modelling and docking results are basically consistent with the metabolic results, which strongly suggest that the structural gene modification is the molecular basis for the OP resistance in this laboratory-selected cotton aphid strain.

A thiamethoxam-resistant strain of cotton aphid (ThR) displayed a 13.79-fold greater resistance to thiamethoxam than a susceptible cotton aphid (SS) strain. Piperonyl butoxide (PBO) and triphenyl phosphate (TPP) synergistically increased the toxicity of thiamethoxam in the resistant strain, whereas diethyl maleate (DEM) did not exhibit significant synergistic effects. Bioassay results indicated that the ThR strain developed increased levels of cross-resistance to bifenthrin (11.71 fold), cyfluthrin (17.90 fold), esfenvalerate (6.85 fold), clothianidin (6.56 fold), methidathion (5.34 fold) and alpha-cypermethrin (4.53 fold) but did not show cross-resistance to malathion, omethoate, acephate, chlorpyrifos, methomyl, sulfoxaflor or imidacloprid. PBO and TPP increased bifenthrin toxicity in the resistant strain by 2.38 and 4.55 fold, respectively. Quantitative real-time PCR results indicated that the mRNA expression levels of the α1, α4-1, α4-2, α5 and α7 subunits decreased significantly by 3.32, 1.60, 2.05, 5.41 and 1.48 fold, respectively, in the resistant strain compared with those in the susceptible strain. However, significant differences were not observed in the expression of the α2, α3 and β1 subunits. No target-site mutations within the α1, α2 and β1 subunits of nicotinic acetylcholine receptors (nAChRs) were detectable in the ThR strain. In conclusion, the levels of thiamethoxam resistance and cross-resistance to other insecticides observed in the ThR strain are likely regulated by two mechanisms, which include the overexpression of detoxification-related P450s and esterase. These results should be useful for the understanding thiamethoxam resistance mechanism and the management of insecticide-resistant cotton aphids in China.

To understand the residual dynamics of pesticides in Lonicera japonica Thunb. and to propose some specific suggestions for the control of pesticide residues, a method for determining hundreds of pesticide residues simultaneously by single quadrupole gas chromatography–mass spectrometry was established and 60 samples from six major distribution channels in 14 different provinces of China were collected and detected. The risk of pesticides was discussed by calculating the levels of contamination as a percentage of acceptable daily intake (ADI). The method established was suitable for detection of pesticide residues in L. japonica. All of the samples had detectable residues and 38 pesticides were found in total. The %ADI values of detectable pesticides ranged from 6.66 × 10−6 to 3.27% and the risk of major kinds detected was quite low (%ADI value less than 1%) other than omethoate and triadimenol. To control and reduce pollution and to minimize health risks, routine monitoring of pesticides in L. japonica is required especially for those that may contribute to risk the most.

An aptasensor is described for electrochemical determination of organophosphorus pesticides (OPPs), specifically of profenofos, phorate, isocarbophos, and omethoate. The method uses a hairpin aptamer as signalling donor. Its 5' and 3' ends were modified with amino groups and the redox probe ferrocene (Fc), respectively. A nanocomposite consisting of graphene oxide and chitosan (GO-chit) was used to immobilize the aptamer via formation of an amide link. Its good conductivity facilitates monitoring of the electrochemical responses. Upon addition of an OPP, it will be bound by the aptamer. This results in an opening of the hairpin structure. Thus, Fc is shifted away from the surface of the electrode. As a result, the impedance increases and the redox signal of Fc decreases. The electrochemical performance, binding capacity and response of the aptasensor for profenofos, phorate, isocarbophos and omethoate were studied. The limits of detection are as low as 0.01, 0.1, 0.01 and 0.1 nM, respectively. Graphical abstract Schematic representation of an electrochemical aptasensor prepared by immobilizing ferrocene (Fc) labeled hairpin aptamer (HP) on the surface of graphene oxide-chitosan (GO-chit) modified electrode, and its application to the determination of organophosphorus pesticides (OPPs) by voltammetry.

A platform for studying insecticide metabolism using in vitro tissues of tea plant was developed. Leaves from sterile tea plantlets were induced to form loose callus on Murashige and Skoog (MS) basal media with the plant hormones 2,4-dichlorophenoxyacetic acid (2,4-D, 1.0 mg L-1) and kinetin (KT, 0.1 mg L-1). Callus formed after 3 or 4 rounds of subculturing, each lasting 28 days. Loose callus (about 3 g) was then inoculated into B5 liquid media containing the same plant hormones and was cultured in a shaking incubator (120 rpm) in the dark at 25 ± 1 °C. After 3-4 subcultures, a cell suspension derived from tea leaf was established at a subculture ratio ranging between 1:1 and 1:2 (suspension mother liquid: fresh medium). Using this platform, six insecticides (5 µg mL-1 each thiamethoxam, imidacloprid, acetamiprid, imidaclothiz, dimethoate, and omethoate) were added into the tea leaf-derived cell suspension culture. The metabolism of the insecticides was tracked using liquid chromatography and gas chromatography. To validate the usefulness of the tea cell suspension culture, the metabolites of thiamethoxan and dimethoate present in treated cell cultures and intact plants were compared using mass spectrometry. In treated tea cell cultures, seven metabolites of thiamethoxan and two metabolites of dimethoate were found, while in treated intact plants, only two metabolites of thiamethoxam and one of dimethoate were found. The use of a cell suspension simplified the metabolic analysis compared to the use of intact tea plants, especially for a difficult matrix such as tea.

Omethoate is a broad category of organophosphorous pesticides (OPs) and has toxic effects on human health under long-term, low-dose exposure. However, the role of omethoate in cancer development remains elusive. The incidence of global head and neck squamous cell carcinomas (HNSCC) has markedly increased in recent years. Thus, we examined whether omethoate induced the proliferation of FaDu cells (a cell line of HNSCC) and if so, what the underlying mechanism was. The study revealed that omethoate induced FaDu cell growth in a dose- and time-dependent manner. Omethoate stimulated FaDu cell proliferation was mainly due to enhancing the G1 to S phase transition by flow cytometry analysis. We also found that omethoate up-regulated cyclin D1, a key gene controlling the G1-S transition. Furthermore, we showed that omethoate was capable of activating the Akt/GSK-3β signaling pathway. Blockage of Akt by siRNA or small molecule inhibitor significantly suppressed omethoate-induced cyclin D1 expression and cell proliferation. Collectively, these findings demonstrated for the first time that omethoate could induce the pharyngeal cancer cell proliferation by activation of the Akt/GSK-3β/cyclin D1 signaling pathway.

A study was carried out to evaluate the dissipation kinetics of field-applied omethoate during wheat storage. Both the identification and metabolic dynamics of omethoate metabolites were analyzed using UPLC-QTOF/MS. The presence of the metabolite dimethyl phosphate (DMP) was confirmed in wheat samples with applied omethoate. This might be because the group attached to the P atom of omethoate is replaced by a hydroxyl group through hydrolysis, thus leading to the formation of the specific metabolite DMP during wheat storage. Although the initial concentrations of DMP in different doses were considerably lower than those of omethoate, the half-life values of DMP were 11.87–31.50 days, which were close to the half-life of the parent omethoate (11.85–30.94 days). This indicates that potential health risks might be caused by dietary exposure to DMP and omethoate. Therefore, more importance should be given to the risk assessment for omethoate and its metabolite DMP in wheat.

We conducted this study in order to assess the pesticide residues in vegetables and examine the related human health risk. Therefore, residues of 23 pesticides (organophosphates, organochlorines, acaricides, fungicides, and insecticides of biological origin) were analysed in the three main vegetable crops grown in Southern Nepal: 27 eggplant, 27 chilli and 32 tomato samples representing (i) conventional (N = 67) and ii) integrated pest management (IPM) fields (N = 19). Pesticide residues were found in 93% of the eggplant samples and in all of the chilli and tomato samples. Multiple residues were observed in 56% of the eggplant samples, 96% of chilli samples and all of the tomato samples. The range (µg/kg) of total detected pesticide residues in eggplants, chillies and tomatoes was 1.71–231, 4.97–507, 13.1–3465, respectively. The most frequently detected pesticides in these vegetables were carbendazim and chloropyrifos. Pesticide residues in 4% of the eggplant, 44% of the tomato and 19% of the chilli samples exceeded the EU maximum residue limits (MRLs). The residues of triazophos, omethoate, chloropyrifos and carbendazim exceeded the EU MRLs. Compared to chilli and eggplant crops, more carbendazim was sprayed onto tomato crops (p < 0.05). We assessed adolescent and adult dietary exposure using hazard quotient (HQ) and hazard index (HI) equations for the identified pesticides. HQ> 1 was observed for chloropyrifos, triazophos and carbendazim in eggplants; profenofos, triazophos, dimethoate, omethoate, chloropyrifos and carbendazim in tomatoes; and dichlorvos and chloropyrifos in chillies. Of all of the HQs, the highest acute HQ (aHQ) was for triazophos (tomato) in adolescents (aHQ=657) and adults (aHQ=677), showing the highest risks of dietary exposure. The cumulative dietary exposure showed a higher HI for organophosphates (HI>83) and a lower HI for organochlorines, acaricides and biological insecticides (HI

The absorption, distribution, metabolism and primary risk evaluation data of four neonicotinoids and two organophosphate insecticides in tea plant (Camellia sinensis L.) were compared. 22 neonicotinoid metabolites and 2 organophosphate metabolites were identified. The amount ratio of each neonicotinoid metabolite to its corresponding parent (M/P) was lower than 0.076 in the treated time. The organophosphates (omethoate and methamidophos) increased sharply, with M/Ps as high as 1.111 and 0.612. The risks evaluation of insecticides and their metabolites in treated leaves on day seven showed that the chronic risk was from the lowest 0.0759 (clothianidin) to highest 43.6409% (dimethoate), and the acute risk was highest 0.0370 for all targets. The calculated combined toxicity of leaves treated with acephate reached 1.5 folds in mature, 1.5 folds in tender leaves than no metabolites, and which of dimethoate were 2.1 folds in mature and 3.7 folds in tender leaves.

Rhopalosiphum padi (Linnaeus) and Sitobion avenae (Fabricius) are the predominant pests coexisting on wheat plants. In this study, the susceptibilities of 29 R. padi and 30 S. avenae populations from 15 provinces in China to pyrethroids (beta-cypermethrin and bifenthrin), neonicotinoids (imidacloprid and thiamethoxam), organophosphates (omethoate and chlorpyrifos) and macrolides (avermectin) were determined during 2018–2019. The median lethal insecticide concentrations (LC50) indicated that R. padi was more sensitive than S. avenae to most of the insecticides. Monitor results showed that most wheat aphid populations were moderately resistant to pyrethroids. Two R. padi populations were highly resistant to beta-cypermethrin with 127.3-fold and 442.8-fold resistance ratio (RR), and two were highly resistant to bifenthrin (RR of 293.9 and 320.6, respectively). One S. avenae population was highly resistant to beta-cypermethrin (RR of 136.8) and one was highly resistant to bifenthrin (RR of 313.4). All populations of two wheat aphids exhibited low to moderate resistance to neonicotinoids (RR

This study aimed to explore the residual dynamics and dietary risk of dimethoate and its metabolite omethoate in celery. Celery was sprayed with 40% dimethoate emulsifiable concentrate (EC) at either a low concentration of 600 g a.i./ha or a high concentration of 900 g a.i./ha. Plants in the seedling, transplanting, or middle growth stages were sprayed once, and the samples were collected 90 days after transplantation. Plants in the harvesting stage were sprayed two or three times. The samples were collected on days 3, 5, 7, 10, 14 and 21 after the last pesticide application. The dimethoate and omethoate compounds were extracted from the celery samples using acetonitrile, and their concentrations were detected using ultra-performance liquid chromatography-tandem mass spectrometry. Also, the dietary risk assessments of dimethoate and omethoate were conducted in various populations and on different foods in China. The metabolism led to the formation of omethoate from dimethoate in the celery. The degradation dynamics of dimethoate and total residues in greenhouse celery followed the first-order kinetic equation. The half-lives of the compounds were 2.42 days and 2.92 days, respectively. The celery which received one application during the harvesting stage had a final residue of dimethoate after 14 days, which was lower than the maximum residue limit (MRL) 0.5 mg kg−1 for Chinese celery. The final deposition of the metabolite omethoate after 28 days was less than the maximum residue limit of 0.02 mg kg−1 for Chinese celery. Furthermore, the risk quotients of dimethoate in celery were less than 1; therefore, the level of chronic risk was acceptable after day 21. Only children aged 2–7 years had an HQ of dimethoate more than 1 (an unacceptable level of acute risk), while the acute dietary risks to other populations were within acceptable levels. It was recommended that any dimethoate applications to celery in greenhouses should happen before the celery reached the harvesting stage, with a safety interval of 28 days.

OBJECTIVE The aim of this study was to explore the association between genetic variations in telomere pathway genes and the level of hydrogen peroxide (H2O2) in omethoate exposure workers. METHODS A total of 180 omethoate exposure workers and 115 healthy controls were recruited. The level of H2O2 in plasma was determined with molybdenic acid colorimetry. Polymerase chain reaction and restriction fragment length was used to detect polymorphisms in POT1 rs1034794, POT1 rs10250202, TERF1 rs3863242, and TERT rs2736098. RESULTS The level of H2O2 in exposure group (4.26 ± 0.71) was significantly higher than that in control group (3.29 ± 0.46). Generalized linear models indicated that risk factors for the increase H2O2 level were exposure [β(95 % CI) = 0.951 (0.806, 1.096), P

In this study, we designed and synthesized Fe3O4/reduced graphene oxide (Fe3O4/rGO) and MIL@MIP, which were characterized using transmission electron microscopy (TEM), X-ray diffraction, Fourier transform infrared (FT-IR), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). Here, reports a novel biomimetic electrochemical sensor (BECS) sensitized with Fe3O4/reduced graphene oxide (Fe3O4/rGO) nanocomposite using MIL@MIP film as recognition element for ultrasensitive quantification of methamidophos or omethoate. The BECS offered fast responses for methamidophos and omethoate with wide linear response ranges of 1.0 × 10−7–1.0 × 10−12 and 1.0 × 10−7–1.0 × 10−13 mol/L, respectively. Under optimized conditions, the limit of detection (LOD; S/N = 3) of the BECS method was 2.67 × 10−13 mol/L for methamidophos and 2.05 × 10−14 mol/L for omethoate. The BECS was applied to detection of methamidophos and omethoate in spiked cucumber and kidney bean samples, and good recoveries varied from 88.2 to 96.9 %. This proposed method was adopted for the determination of the methamidophos or omethoate residues in the rape sample, and the results were also verified using the method of gas chromatography.

A novel magnetic mesoporous nanomicrospheres Fe3O4@SiO2@mTiO2 were synthetized and characterized by a series of techniques including FE-TEM, EDS, FE-SEM, PXRD, XPS, BET, TGA as well as VSM, and subsequently tested as a photocatalyst for the degradation of Acephate, Omethoate, and Methyl parathion under UV irradiation. The well-designed nanomicrospheres exhibit a pure and highly crystalline anatase TiO2 layer, large specific surface area, and high-magnetic-response. Photocatalytic degradation of the three organophosphorus pesticides (OPPs) and the formation intermediates were identified using HPLC, TOC-Vcpn, IC, pH meter and GC-MS. Acephate, Omethoate, and Methyl parathion disappeared after 45min, 45min, and 80min UV illumination, respectively. At the end of the treatment, the total organic carbon (TOC) of the OPPs was reduced 80-85%. The main mineralization products were SO4(2-), NO3(-) and PO4(3-) and Omethoate additionally formed NO2(-). Based on the results, we proposed the photocatalytic degradation pathways for Acephate, Omethoate, and Methyl parathion.

The effect of different kinds of pesticide residues in grapes on alcoholic fermentation by Saccharomyces cerevisiae was evaluated. Among four types of pesticides added into the grape slurry, omethoate, triadimefon and cyhalothrin did not inhibit the alcoholic fermentation at their proposed spraying concentration of 0.21, 0.10 and 0.10 g L−1, respectively, whereas chlorothalonil concentration above 0.03 g L−1 behaved significantly negative influence on both S. cerevisiae growth and alcoholic fermentation efficiency. When the chlorothalonil concentration was lower than 0.01 g L−1, the fermentation proceeded smoothly without any degradation of chlorothalonil. Considering the cumulative toxicity and adverse effect of chlorothalonil on fermentation, chlorothalonil hydrolytic dehalogenase (Chd) extracellularly expressed from the recombinant Bacillus subtilis WB800 was used to pretreat the chlorothalonil-contaminated grape slurry. After treatment by the Chd enzyme in an activity of 7.25 mU L−1 slurry for 60 min, the inhibition effect could be substantially eliminated even at an initial concentration of 0.10 g L−1 chlorothalonil. This study provides a potential approach for solving the conflict in fermentation industry with pesticides inhibition.

Pesticides and antidepressants are frequently misused in drug-facilitated crime because of their toxicological effect and easy-availability. Therefore, it is essential for the development of a simple and reliable method for the determination of these organic toxicants in biological fluids. Here, we report on an applicable method by the combination of optimized liquid-liquid extraction (LLE) procedure and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to identify and quantify dimethoate, omethoate, dichlorvos, carbofuran, fenpropathrin, diazepam, estazolam, alprazolam, triazolamm, chlorpromazine, phenergan, barbitone and phenobarbital in human blood. The method demonstrated a linear calibration curve in range of 20 - 500 μg/L (r > 0.994). The accuracy evaluated by recovery spiked at three different concentrations (50, 100 and 200 μg/L) was in the range of 58.8 - 83.1% with a relative standard deviations (RSD) of 3.7 - 7.4%. The limits of quantification ranged over 6.7 - 33.3 μg/L. This method was proved to be simple and reliable, and was thus successfully applied to forensic toxicology.

A new methodology for the retrospective screening of pesticide metabolites in ambient air was developed, using liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS), including two systematic workflows (i) post-run target screening (suspect screening) and (ii) non-target screening. An accurate-mass database was built and used for the post-run screening analysis. The database contained 240 pesticide metabolites found in different matrixes such as air, soil, water, plants, animals and humans. For non-target analysis, a "fragmentation-degradation" relationship strategy was selected. The proposed methodology was applied to 31 air samples (PM10) collected in the Valencian Region (Spain). In the post-target analysis 34 metabolites were identified, of which 11 (3-ketocarburan, carbofuran-7-phenol, carbendazim, desmethylisoproturon, ethiofencarb-sulfoxide, malaoxon, methiocarb-sulfoxide, N-(2-ethyl-6-methylphenyl)-L-alanine, omethoate, 2-hydroxy-terbuthylazine, and THPAM) were confirmed using analytical standards. The semiquantitative estimated concentration ranged between 6.78 and 198.31 pg m(-3). Likewise, two unknown degradation products of malaoxon and fenhexamid were elucidated in the non-target screening.

This study was designed to investigate organophosphorus pesticides (OPs) concentrations in fresh vegetables and estimate potential health risks to inhabitants. A total of 214 samples of seven types of vegetables were collected from Changchun, the capital of Jilin province, one of the most important vegetable production areas. The eleven OPs were analyzed by gas chromatography coupled with flame photometric detector (GC-FPD). Results showed that 23.4% of samples contained OPs above maximum residue limit (MRL), 68.7% of samples below MRL and only 7.9% of samples were found free of OPs. Detection rates of OPs decreased in the following order: diazinon (82.2%) > phorate (45.8%) > dimethoate (29.4%) > parathion-methyl (27.6%) > omethoate (23.8%) > dichlorvos (22.9%) > fenitrothion (21%) > fenthion (18.7%) > parathion (18.2%) > methamidophos (17.3%) > malathion (12.1%). The OPs levels were higher for leafy than for non-leafy vegetables. The percentages of OPs above MRL: welsh onion (82.5%) > radish (37.5%) > pepper (17.2%) > Chinese cabbage (14.3%) > cucumber (3.2%) > eggplant (2.9%) > tomato (0%). 49.5% samples contained two or more OPs. The average target hazard quotients (ave THQ) were all less than one and the average Hazard Index (ave HI) for adults and children were 0.448 and 0.343, respectively. It is concluded that inhabitants who are exposed to average OPs levels may not be endangered by health risk.

Organophosphate insecticides (OI) are widely used. To humans the main routes of exposure are skin and inhalation. For this, keratinocytes (HaCaT) and bronchial cells (NL-20) were used as cell culture models to evaluate the effects of OI. The aim of this study was to evaluate the effect of four OI on HaCaT and NL-20 cells: azinphos-methyl, (AM); parathion-methyl (PM); omethoate (OM); and methamidophos (MET). Cells were exposed to 0.1, 1 and 10 μg/μL of each. Results showed a decrease in cell viability in both cell lines. Viability of the NL-20 cell line decreased with the three concentrations of OM. All differences were significant (p < 0.05). Genotoxic damage, evaluated through the comet assay, was observed in both cell lines with AM. NL-20 cell line was more sensitive than HaCaT. Higher concentrations of the insecticides except MET, induced cell death. MET caused DNA damage in HaCaT cells at all concentrations. Differences were significant (p < 0.05). Both cell lines revealed the presence of single membrane vacuoles of different sizes when exposed to 1 μg/μL of each insecticide. Quantitative real time-polymerase chain reaction (RT-qPCR) showed an increase of BN1 gene in HaCaT by effect of AM and MET at 1 μg/μL. In conclusion, all the insecticides induced different levels of cyto and genotoxic effects in both cell lines.