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1.
Food Chem ; 372: 131153, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34628119

RESUMO

We searched for five neonicotenoids (namely acetamiprid, clothianidin, imidacloprid, thiacloprid and thiamethoxam) in 67 samples of fruits, leaves, pollen and honey via HPLC-MS by employing QueChERs for extraction and purification. Clothianidin was never detected, while imidacloprid was identified in apple (9.2 µg/kg) and pollen (18-28 µg/Kg), thiacloprid in peaches (21-35 µg/kg) and acetamiprid was identified in the hazel leaves (1266 µg/kg), honey (13-26 µg /Kg) and pollen (11-24 µg/kg). Since the levels found of acetamiprid in hazel, honey and pollen were concerning, we accomplished a study to identify and characterize the possible transformation products via a laboratory simulation. The methodology exploited the analysis by HPLC-HRMS and its application in all matrices. We identify twelve transformation products, whose formation involved dimerization, hydroxylation, oxidation, demethylation and cleavage of the molecule. Three of them were also detected in hazel leaves.


Assuntos
Mel , Inseticidas , Frutas/química , Mel/análise , Inseticidas/análise , Neonicotinoides , Nitrocompostos , Tiametoxam
2.
J Sci Food Agric ; 102(1): 417-424, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34143904

RESUMO

BACKGROUND: Thiamethoxam is widely used to control pests in Chinese kale, popularly consumed leafy vegetables. The potential risk to the environment and human health has aroused much public concern. Therefore, it is important to investigate the degradation behavior, residue distribution and dietary risk assessment of thiamethoxam in Chinese kale. RESULTS: A sensitive analytical method for determination of thiamethoxam and its metabolite clothianidin residue in Chinese kale was established and validated through a quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The recoveries were 85.4-101.2% for thiamethoxam and 79.5-108.1% for clothianidin, with the relative standard deviations (RSDs) of 0.9-10.2% and 1.8-6.0%, respectively. For the dissipation kinetics, the data showed that thiamethoxam in Chinese kale was degraded with the half-lives of 4.1 to 4.5 days. In the terminal residue experiments, the residues of thiamethoxam were 0.017-0.357 mg kg-1 after application 2-3 times with a preharvest interval (PHI) of 7 days under the designed dosages. The chronic and acute dietary exposure assessment risk quotient (RQ) values of thiamethoxam in Chinese kale for different Chinese consumers were 0.08-0.19% and 0.05-0.12%, respectively, and those of clothianidin were 0.01-0.04% and 0.02-0.04%, respectively, all of the RQ values were lower than 100%. CONCLUSION: Thiamethoxam in Chinese kale was rapidly degraded following first-order kinetics models. The dietary risk of thiamethoxam and clothianidin through Chinese kale was negligible to consumers. The results from this study are important reference for Chinese governments to developing criteria for the safe and rational use of thiamethoxam, setting maximum residue levels (MRLs), monitoring the quality safety of agricultural products and protecting consumer health. © 2021 Society of Chemical Industry.


Assuntos
Brassica/química , Cromatografia Líquida/métodos , Guanidinas/metabolismo , Neonicotinoides/metabolismo , Resíduos de Praguicidas/química , Resíduos de Praguicidas/metabolismo , Espectrometria de Massas em Tandem/métodos , Tiametoxam/química , Tiametoxam/metabolismo , Tiazóis/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brassica/metabolismo , Criança , Pré-Escolar , China , Exposição Dietética/efeitos adversos , Exposição Dietética/análise , Feminino , Contaminação de Alimentos/análise , Humanos , Cinética , Masculino , Pessoa de Meia-Idade , Medição de Risco , Verduras/química , Verduras/metabolismo , Adulto Jovem
3.
Anal Chim Acta ; 1183: 338938, 2021 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-34627522

RESUMO

The spiropyran (SP) compound is a typical photochromic compound. Its merocyanine configuration (MC) can accept energy and be excited by visible light, while the closed-loop configuration cannot. In this work, the SP was wrapped in ß-cyclodextrin (ß-CD-SP) firstly. When it was competitively replaced by thiamethoxam and dissociated out of ß-CD, it would be converted to MC, which could be excited by visible light around 550 nm to produce red fluorescence. Here, CsPbBr3 was selected as the energy donor based on the principle of fluorescence resonance energy transfer (FRET). In order to connect with ß-CD-SP and improve its stability, CsPbBr3 was wrapped in mesoporous silica, and then the second wrapping was performed to block those mesopores and the amination reaction was carried out (NH2-SiO2@CsPbBr3). Subsequently, NH2-SiO2@CsPbBr3 with green fluorescence (506 nm) was used as the internal standard and excitation light source for MC, and the red fluorescence of MC was used as the response signal to construct a ratiometric fluorescence sensor. When thiamethoxam was added and excited by 365 nm ultraviolet light, the energy would be transferred from NH2-SiO2@CsPbBr3 (506 nm) that emitted green fluorescence to MC, which emitted red fluorescence. So, the fluorescence color changed from green to yellow to red with the addition of the thiamethoxam. This sensor was employed to detect thiamethoxam in soil and yam.


Assuntos
Transferência Ressonante de Energia de Fluorescência , Dióxido de Silício , Benzopiranos , Indóis , Nitrocompostos , Tiametoxam
4.
Ecotoxicol Environ Saf ; 227: 112917, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34678628

RESUMO

Imidacloprid (IMI) and thiamethoxam (THM) are two commonly applied neonicotinoid insecticides. IMI and THM could cause negative impacts on non-target organisms like bees. However, the information about neurotoxicity of IMI and THM in fish is still scarce. Here we investigated the effects of IMI and THM on locomotor behavior, AChE activity, and transcription of genes related to synaptic transmission in zebrafish exposed to IMI and THM with concentrations of 50 ng L-1 to 50,000 ng L-1 at 14 day post fertilization (dpf), 21 dpf, 28 dpf and 35 dpf. Our results showed that IMI and THM significantly influenced the locomotor activity in larvae at 28 dpf and 35 dpf. THM elevated AChE activity at 28 dpf. The qPCR data revealed that IMI and THM affected the transcription of marker genes belonging to the synapse from 14 dpf to 35 dpf. Furthermore, IMI and THM mainly affected transcription of key genes in γ-aminobutyric acid, dopamine and serotonin pathways in larvae at 28 dpf and 35 dpf. These results demonstrated the neurotoxicity of IMI and THM in zebrafish. The findings from this study suggested that IMI and THM in the aquatic environment may pose potential risks to fish fitness and survival.


Assuntos
Inseticidas , Poluentes Químicos da Água , Animais , Abelhas , Inseticidas/análise , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Transmissão Sináptica , Tiametoxam , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética
5.
Ecotoxicol Environ Saf ; 225: 112744, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34481358

RESUMO

Thiamethoxam, an insecticide with high usage and large amounts of environmental residues, has been reported to affect the pupation and survival of honey bee larvae at sublethal concentrations. The molecular mechanisms are not fully understood. In this study, we measured the response of juvenile hormone (JH) to environmental concentrations of thiamethoxam using liquid chromatography-tandem mass spectrometry (LC-MS/MS), monitored the dynamic changes in the transcription of genes encoding major JH metabolic enzymes (CYP15A1, FAMET, JHAMT and JHE) using RT-qPCR, and analysed the transcriptome changes in worker larvae under thiamethoxam stress using RNA-seq. Thiamethoxam significantly increased the levels of JH3 in honey bee larvae, but no significant changes in the transcript levels of the four major metabolic enzymes were observed. Thiamethoxam exposure resulted in 140 differentially expressed genes (DEGs). P450 CYP6AS5 was upregulated, and some ion-related, odourant-related and gustatory receptors for sugar taste genes were altered significantly. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that amino acid metabolism and protein digestion and absorption were influenced by thiamethoxam. These changes may do harm to honey bee caste differentiation, foraging behaviour related to sensory perception and nutrient levels of bee colonies. These results represent the first assessment of the effects of thiamethoxam on JH in honey bee larvae and provides a new perspective and molecular basis for the study of JH regulation and thiamethoxam toxicity to honey bees.


Assuntos
Hormônios Juvenis , Espectrometria de Massas em Tandem , Animais , Abelhas/genética , Cromatografia Líquida , Hormônios Juvenis/toxicidade , Larva/genética , Tiametoxam
6.
PLoS One ; 16(9): e0250311, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34529690

RESUMO

The soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) is a primary pest of soybeans and poses a serious threat to soybean production. Our studies were conducted to understand the effects of different concentrations of insecticides (imidacloprid and thiamethoxam) on A. glycines and provided critical information for its effective management. Here, we found that the mean generation time and adult and total pre-nymphiposition periods of the LC50 imidacloprid- and thiamethoxam-treatment groups were significantly longer than those of the control group, although the adult pre-nymphiposition period in LC30 imidacloprid and thiamethoxam treatment groups was significantly shorter than that of the control group. Additionally, the mean fecundity per female adult, net reproductive rate, intrinsic rate of increase, and finite rate of increase of the LC30 imidacloprid-treatment group were significantly lower than those of the control group and higher than those of the LC50 imidacloprid-treatment group (P < 0.05). Moreover, both insecticides exerted stress effects on A. glycines, and specimens treated with the two insecticides at the LC50 showed a significant decrease in their growth rates relative to those treated with the insecticides at LC30. These results provide a reference for exploring the effects of imidacloprid and thiamethoxam on A. glycines population dynamics in the field and offer insight to agricultural producers on the potential of low-lethal concentrations of insecticides to stimulate insect reproduction during insecticide application.


Assuntos
Afídeos/crescimento & desenvolvimento , Inseticidas/efeitos adversos , Neonicotinoides/efeitos adversos , Nitrocompostos/efeitos adversos , Soja/parasitologia , Tiametoxam/efeitos adversos , Animais , Afídeos/efeitos dos fármacos , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Feminino , Fertilidade/efeitos dos fármacos , Dose Letal Mediana , Masculino , Dinâmica Populacional
7.
Ecotoxicol Environ Saf ; 223: 112581, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34352576

RESUMO

The increasing use of insecticides, promoted by the intensification of agriculture, has raised concerns about their influence on the decline of bee colonies, which play a fundamental role in pollination. Thus, it is fundamental to elucidate the effects of insecticides on bees. This study investigated the damage caused by a sublethal concentration of thiamethoxam - TMX (0.0227 ng/µL of feed) in the head and midgut of Africanized Apis mellifera, by analyzing the enzymatic biomarkers, oxidative stress, and occurrence of lipid peroxidation. The data showed that the insecticide increased acetylcholinesterase activity (AChE) and glutathione-S-transferase (GST), whereas carboxylesterase (CaE3) activity decreased in the heads. Our results indicate that the antioxidant enzymes were less active in the head because only glutathione peroxidase (GPX) showed alterations. In the midgut, there were no alkaline phosphatase (ALP) or superoxide dismutase (SOD) responses and a decrease in the activity of CaE was observed. Otherwise, there was an increase in GPX, and the TBARS (thiobarbituric acid reactive substances) assay also showed differences in the midgut. The TBARS (thiobarbituric acid reactive substances) assay also showed differences in the midgut. The results showed enzymes such as CaE3, GST, AChE, ALP, SOD, and GPX, as well as the TBARS assay, are useful biomarkers on bees. They may be used in combination as a promising tool for characterizing bee exposure to insecticides.


Assuntos
Inseticidas , Nitrocompostos , Animais , Abelhas , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Oxazinas/toxicidade , Tiametoxam , Tiazóis/toxicidade
8.
J Insect Sci ; 21(4)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34374762

RESUMO

Honey bees continue to face challenges relating to the degradation of natural flowering habitats that limit their access to diverse floral resources. While it is known that nectar and pollen provide macronutrients, flowers also contain secondary metabolites (phytochemicals) that impart benefits including increased longevity, improved gut microbiome abundance, and pathogen tolerance. Our study aims to understand the role of phytochemicals in pesticide tolerance when worker bees were fed with sublethal doses (1 ppb and 10 ppb) of thiamethoxam (TMX), a neonicotinoid, in 20% (w/v) sugar solution supplemented with 25 ppm of phytochemicals-caffeine, kaempferol, gallic acid, or p-coumaric acid, previously shown to have beneficial impacts on bee health. The effect of phytochemical supplementation during pesticide exposure was context-dependent. With 1 ppb TMX, phytochemical supplementation increased longevity but at 10 ppb TMX, longevity was reduced suggesting a negative synergistic effect. Phytochemicals mixed with 1 ppb TMX increased mortality in bees of the forager-age group but with 10 ppb TMX, mortality of the inhive-age group increased, implying the possibility of accumulation effect in lower sublethal doses. Given that the phytochemical composition of pollen and nectar varies between plant species, we suggest that the negative impacts of agrochemicals on honey bees could vary based on the phytochemicals in pollen and nectar of that crop, and hence the effects may vary across crops. Analyzing the phytochemical composition for individual crops may be a necessary first step prior to determining the appropriate dosage of agrochemicals so that harm to bees Apis mellifera L. is minimized while crop pests are effectively controlled.


Assuntos
Abelhas , Suplementos Nutricionais , Inseticidas , Compostos Fitoquímicos , Tiametoxam , Animais , Cafeína , Ácidos Cumáricos , Ácido Gálico , Quempferóis
9.
Funct Plant Biol ; 48(10): 994-1004, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34210384

RESUMO

Neonicotinoid insecticides are used against the wide range of pests to protect plants. The influence of neonicotinoids on target and non-target insects is well understood. Hence, there are controversial opinions about the effect of neonicotinoids on the plants. We investigated pigments and photosynthetic primary reactions in two maize genotypes (the inbred line zppl 225 and hybrid zp 341) under thiamethoxam (TMX) treatment by root irrigation. It was found that the effect of TMX depended on pesticide application techniques and selection of maize genotype. TMX was added to the soil by root irrigation on the 4th and 8th days after planting, and photosynthetic characteristics monitored on the 10th and 12th days after planting. The primary photochemical reactions in PSII (Fv/Fm) of both maize genotypes were not affected under two variants of TMX treatment during all growing period. The hybrid zp341 was shown to be more susceptible to both TMX treatments, demonstrating a decrease in photosynthetic characteristics (JIP-test parameters) as well as changes in the content of pigments and in the conformation of the carotenoid molecule. Our findings suggest that the combination of fluorescence method and Raman spectroscopy is a perspective tool for monitoring plant state under pesticide application.


Assuntos
Fotossíntese , Zea mays , Genótipo , Neonicotinoides/toxicidade , Tiametoxam , Zea mays/genética
10.
Environ Pollut ; 289: 117813, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34332171

RESUMO

Seed coating ('seed treatment') is the leading delivery method of neonicotinoid insecticides in major crops such as soybean, wheat, cotton and maize. However, this prophylactic use of neonicotinoids is widely discussed from the standpoint of environmental costs. Growing soybean plants from neonicotinoid-coated seeds in field, we demonstrate that soybean aphids (Aphis glycines) survived the treatment, and excreted honeydew containing neonicotinoids. Biochemical analyses demonstrated that honeydew excreted by the soybean aphid contained substantial concentrations of neonicotinoids even one month after sowing of the crop. Consuming this honeydew reduced the longevity of two biological control agents of the soybean aphid, the predatory midge Aphidoletes aphidimyza and the parasitic wasp Aphelinus certus. These results have important environmental and economic implications because honeydew is the main carbohydrate source for many beneficial insects in agricultural landscapes.


Assuntos
Afídeos , Inseticidas , Animais , Agentes de Controle Biológico , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos , Oxazinas , Sementes , Soja , Tiametoxam , Tiazóis
11.
Environ Toxicol ; 36(10): 2051-2061, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34181816

RESUMO

Thiamethoxam (TMX) belongs to the neonicotinoid insecticide family and may evoke marked endocrine disruption. In this study, the reproductive toxicity of TMX on male rats was assessed along with the ability of Saussurea lappa (costus roots) and/or Silybum marianum extract (SM) to alleviate TMX toxicity. Male rats were allocated to seven groups and orally treated daily for 4 weeks: Control (saline), Costus (200 mg/kg), SM (150 mg/kg), TMX (78.15 mg/kg), TMX-costus, TMX-SM, and TMX-costus-SM (at the aforementioned doses). Compared with control group, TMX administration induced reductions in testicular levels of glutathione and antioxidant activities of SOD and CAT. In addition, TMX-exposed rats showed lower serum testosterone hormonal levels as well as higher malondialdehyde and nitric acid levels were detected in TMX-administered rats. On a molecular basis, mRNA expressions of StAR, CYP17a, 3ß-HSD, SR-B1, and P450scc genes were significantly down-regulated in TMX group, whereas the expression of LHR and aromatase genes was up-regulated. Moreover, TMX-induced testicular damage was confirmed by histopathological screening. Importantly, however, the administration of either costus roots or SM significantly alleviated all aforementioned TMX-induced changes, indicating the effective antioxidant activities of these plant products. Interestingly, simultaneous treatment with costus root and SM provided better protection against TMX reproduction toxicity than treatment with either agent alone.


Assuntos
Saussurea , Animais , Antioxidantes , Peroxidação de Lipídeos , Cardo-Mariano , Estresse Oxidativo , Ratos , Tiametoxam
12.
J Hazard Mater ; 417: 126017, 2021 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-34004582

RESUMO

The extensive use of neonicotinoid pesticides in the past two decades caused serious impacts on many kinds of living beings. Therefore, it has been strongly suggested to detoxify and eliminate neonicotinoids' residual levels in environment. Here, the degradation and detoxification of thiamethoxam (THX) by white-rot fungus Phanerochaete chrysosporium was conducted. Results shown that P. chrysosporium can tolerate THX and degraded 49% of THX after incubation for 15 days, and then 98% for 25 days at the initial concentration of 10 mg/L, which indicates the excellent degradation ability of this fungus to THX. Based on the by-products identified, THX underwent dechlorination, nitrate reduction, and C-N cleavage between the 2-chlorothiazole ring and oxadiazine. (Z)-N-(3-methyl-1,3,5-oxadiazinan-4-ylidene)nitramide and 3-methyl-1,3,5-oxadiazinan-4-imine were identified as the main metabolites. The impacts of THX and its corresponding degradation intermediates on the growth of E. coil and Microcystis aeruginosa as well as the germination of rape and cabbage demonstrated that P. chrysosporium effectively degrades THX into metabolites and reduces its biotoxicity. The present work demonstrates that P. chrysosporium can be effectively used for degradation and detoxification of THX.


Assuntos
Inseticidas , Phanerochaete , Biodegradação Ambiental , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Tiametoxam
13.
Environ Sci Pollut Res Int ; 28(38): 53193-53207, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34023994

RESUMO

Contamination with neonicotinoids is a global problem affecting environment and target and non-target organisms including plants. The present study explored the potential genotoxic and cytotoxic effects of the insecticides Actara 25 WD and Nuprid 200 SL containing the active substances thiamethoxam (TMX) and imidacloprid (IMI), respectively, on cultivated sunflower (Helianthus annuus L.). The half maximal effective concentration (½EC50) of the tested substances was calculated using a dose-response inhibition analysis of the growth of plant roots relative to the corresponding controls. Application of approximately ½EC50 or higher TMX doses significantly increased the antioxidant activity in sunflower leaves, whereas IMI led to a significant decrease in root antioxidant capacity, indicating organ-specific insecticide effects on sunflower plants. Even low doses (½EC50) of the studied neonicotinoids led to irregularities in mitotic phases and abnormalities in the cytokinesis and chromosome segregation, such as bridges, laggards, stickiness, and C-mitosis. Genotoxic effects manifested by a dose-independent induction of primary DNA damages and retrotransposon dynamics were also observed. The used set of physiological, biochemical, and genetic traits provides new information about the organ-specific effects of neonicotinoids in sunflower plants and elaborates on the complexity of mechanisms underpinning these effects that include DNA damages, cytokinesis defects, and genome instability.


Assuntos
Helianthus , Inseticidas , Dano ao DNA , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Tiametoxam
14.
Sci Total Environ ; 785: 146955, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33957580

RESUMO

Insecticides are contributing to global insect declines, thereby creating demand to understand the mechanisms underlying reduced fitness. In the eusocial Hymenoptera, inclusive fitness depends on successful mating of male sexuals (drones) and efficient collaborative brood care by female workers. Therefore, sublethal insecticide effects on sperm and glands used in larval feeding (hypopharyngeal glands (HPG)) would provide key mechanisms for population declines in eusocial insects. However, while negative impacts for bumblebee colony fitness have been documented, the effects of insecticide exposure on individual physiology are less well understood. Here, we show that field-realistic concentrations (4.5-40 ng ml-1) of the neonicotinoid insecticide thiamethoxam significantly impair Bombus terrestris sperm and HPGs, thereby providing plausible mechanisms underlying bumblebee population decline. In the laboratory, drones and workers were exposed to five thiamethoxam concentrations (4.5 to 1000 ng ml-1). Then, survival, food consumption, body mass, HPG development, sperm quantity and viability were assessed. At all concentrations, drones were more exposed than workers due to higher food consumption. Increased body mass was observed in drones starting at 20 ng ml-1 and in workers at 100 ng ml-1. Furthermore, environmentally realistic concentrations (4.5-40 ng ml-1) did not significantly affect survival or consumption for either sex. However, thiamethoxam exposure significantly negatively affected both sperm viability and HPG development at all tested concentrations. Therefore, the results indicate a trade-off between survival and fitness components, possibly due to costly detoxification. Since sperm and HPG are corner stones of colony fitness, the data offer plausible mechanisms for bumblebee population declines. To adequately mitigate ongoing biodiversity declines for the eusocial insects, this study suggests it is essential to evaluate the impact of insecticides on fitness parameters of both sexuals and workers.


Assuntos
Inseticidas , Animais , Abelhas , Feminino , Humanos , Insetos , Inseticidas/toxicidade , Masculino , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Reprodução , Espermatozoides , Tiametoxam
15.
Food Chem ; 359: 129936, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33957328

RESUMO

In this work, new selective and sensitive dual-template molecularly imprinted polymer nanoparticles (MIPs) were synthesized and characterized. Sorbent MIPs were investigated for simultaneous extraction and clean-up of thiamethoxam and thiacloprid from light and dark honey samples. In this study, ultra-high-performance liquid chromatography-tandem mass spectrometry triple-quadrupole (UHPLC-MS/MS) (QQQ) was used to detect and quantify the pesticides. The kinetic model with adsorption kinetics of sorbent was investigated. The optimal adsorption conditions were 80 mg of polymer MIPs, a 30-min extraction time, and a pH of 7. The detection limit (LOD) and the quantification limit (LOQ) varied from 0.045 to 0.070 µg kg-1 and from 0.07 to 0.10 µg kg-1, respectively. The intra-day and inter-day precision (RSD, %) ranged from 1.3 to 2.0% and from 8.2 to 12.0%, respectively. The recovery of thiamethoxam and thiacloprid ranged from 96.8 to 106.5% and 95.3 to 104.4%, respectively, in light and dark honey samples.


Assuntos
Mel/análise , Fenômenos Magnéticos , Impressão Molecular/métodos , Nanopartículas/química , Neonicotinoides/isolamento & purificação , Praguicidas/isolamento & purificação , Polímeros/química , Tiametoxam/isolamento & purificação , Tiazinas/isolamento & purificação , Adsorção , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Magnetismo , Polímeros Molecularmente Impressos , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
16.
J AOAC Int ; 104(5): 1282-1288, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-33876822

RESUMO

BACKGROUND: Thiamethoxam, a neonicotinoid insecticide, has been widely accepted for the control of sucking and certain chewing pests. Through different routes, i.e., wind drift, leaching, and surface runoff, it can reach non-target areas, which include humans as well. Therefore the fate of thiamethoxam in food grains and soil is of prime importance, entailing a need for pesticide use to be subject to steady observation. OBJECTIVE: The review aimed to validate the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for the detection of thiamethoxam and its metabolites in wheat leaves, grain, straw, and soil using liquid chromatography-tandem mass spectrometry (LC-MS/MS). METHOD: The QuEChERS method allows sample extraction by acetonitrile followed by cleanup with a primary secondary amine sorbent, magnesium sulphate, and graphitized carbon black. The method was validated in terms of selectivity, linearity, LOD, LOQ, matrix match, accuracy, and precision. The estimation of residues was done by LC-MS/MS. RESULTS: The recovery of thiamethoxam and its metabolites in wheat and soil samples was in the range of 81.22-98.14%. The LOQ for thiamethoxam and its metabolites was 0.01 mg/kg. The matrix effect values were in the acceptable range of -20 to +20%. CONCLUSIONS: The method allows a simple and fast extraction of thiamethoxam and its metabolites from wheat leaves, grain, straw, and soil. It could be helpful in the evaluation of regulatory and food safety decisions regarding the use of neonicotinoids. HIGHLIGHTS: The method was validated according to the European Commission SANTE/12682/2019 guidelines. An accurate, simple, and sensitive analytical method was validated for thiamethoxam and its metabolites.


Assuntos
Resíduos de Praguicidas , Espectrometria de Massas em Tandem , Cromatografia Líquida , Humanos , Resíduos de Praguicidas/análise , Solo , Tiametoxam/análise , Triticum
17.
Environ Pollut ; 284: 117106, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-33930781

RESUMO

The ongoing loss of global biodiversity is endangering ecosystem functioning and human food security. While environmental pollutants are well known to reduce fertility, the potential effects of common neonicotinoid insecticides on insect fertility remain poorly understood. Here, we show that field-realistic neonicotinoid exposure can drastically impact male insect fertility. In the laboratory, male and female solitary bees Osmia cornuta were exposed to four concentrations of the neonicotinoid thiamethoxam to measure survival, food consumption, and sperm traits. Despite males being exposed to higher dosages of thiamethoxam, females revealed an overall increased hazard rate for survival; suggesting sex-specific differences in toxicological sensitivity. All tested sublethal concentrations (i.e., 1.5, 4.5 and 10 ng g-1) reduced sperm quantity by 57% and viability by 42% on average, with the lowest tested concentration leading to a reduction in total living sperm by 90%. As the tested sublethal concentrations match estimates of global neonicotinoid pollution, this reveals a plausible mechanism for population declines, thereby reflecting a realistic concern. An immediate reduction in environmental pollutants is required to decelerate the ongoing loss of biodiversity.


Assuntos
Ecossistema , Inseticidas , Animais , Abelhas , Feminino , Fertilidade , Inseticidas/toxicidade , Masculino , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Tiametoxam , Tiazóis/toxicidade
18.
Arch Environ Contam Toxicol ; 80(4): 691-707, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33880625

RESUMO

This research investigated the adverse effects of neonicotinoids on the Northwestern salamander (Ambystoma gracile; NWS) after acute and subchronic exposures during early aquatic life stages via whole organism (i.e., growth, development) and molecular (i.e., gene expression) level endpoints. In a 96-h exposure, NWS larvae were exposed to four imidacloprid concentrations (250, 750, 2250, 6750 µg/L) and a water control treatment, and no effects on survival, body weight, snout-vent length (SVL), and total body length were observed. However, a significant 1.70- and 2.33-fold decrease in thyroid receptor ß (TRß) mRNA expression levels were detected in the larvae exposed to 750 and 2250 µg/L imidacloprid, respectively, compared with the larvae in the water control. In subsequent subchronic experiments, NWS larvae were exposed for 35 days to imidacloprid alone and an equal part mixture of neonicotinoids (imidacloprid, clothianidin, and thiamethoxam (ICT)) at three concentrations (10, 100 and 1000 µg total neonicotinoids/L) and a water control. In these experiments, there were no effects on larval survival, body weight, SVL, and total body length. However, advanced development of larvae in the 100 µg/L imidacloprid treatment was observed compared with the control after 35-day imidacloprid exposure, providing some evidence of disruption of the thyroid endocrine axis at an environmentally relevant concentration. Ultimately, there is a paucity of studies conducted examining the sensitivity of salamanders to pollutants; thus, this study reports novel findings that will contribute to understanding the sensitivity of a Caudate amphibian model to a common environmental pollutant.


Assuntos
Inseticidas , Urodelos , Animais , Inseticidas/toxicidade , Larva , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Tiametoxam
19.
Ecotoxicology ; 30(5): 828-835, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33851336

RESUMO

Exposure to sublethal concentrations can have adverse effects on certain individuals, but, can also favor survival and reproduction of others. This study aimed to evaluate the effects of exposing Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae) adults to LC50 of spinetoram and lambda-cyhalothrin and field rate of thiamethoxam on their mating, reproductive output and longevity. The LC50 for lambda-cyhalothrin and for spinetoram were 7.83 and 32.91 ng a.i./cm2, respectively. Thiamethoxam, in the concentrations tested, was not toxic to D. suzukii, therefore, we use the recommended concentration for strawberry, 231.25 ng a.i./cm2, in the sublethal tests. Insects exposed to LC50 of lambda-cyhalothrin were more likely to mate, but presented shorter copula. Sublethal exposure to thiamethoxam lead to an increase in total fecundity. Among the insecticides tested, spinetoram presented the least expressive effects. Longevity was not affected by any of the tested insecticides. Results presented in this study are relevant to D. suzukii management since the stimulatory effects shown on this pest species can collaborate to outbreaks and insecticide resistance.


Assuntos
Inseticidas , Animais , Drosophila , Controle de Insetos , Resistência a Inseticidas , Inseticidas/toxicidade , Reprodução , Tiametoxam
20.
Environ Sci Process Impacts ; 23(5): 678-688, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-33889902

RESUMO

Neonicotinoids in aquatic systems have been predominantly associated with agriculture, but some are increasingly being linked to municipal wastewater. Thus, the aim of this work was to understand the municipal wastewater contribution to neonicotinoids in a representative, characterized effluent-dominated temperate-region stream. Our approach was to quantify the spatiotemporal concentrations of imidacloprid, clothianidin, thiamethoxam, and transformation product imidacloprid urea: 0.1 km upstream, the municipal wastewater effluent, and 0.1 and 5.1 km downstream from the wastewater outfall (collected twice-monthly for one year under baseflow conditions). Quantified results demonstrated that wastewater effluent was a point-source of imidacloprid (consistently) and clothianidin (episodically), where chronic invertebrate exposure benchmarks were exceeded for imidacloprid (36/52 samples; 3/52 > acute exposure benchmark) and clothianidin (8/52 samples). Neonicotinoids persisted downstream where mass loads were not significantly different than those in the effluent. The combined analysis of neonicotinoid effluent concentrations, instream seasonality, and registered uses in Iowa all indicate imidacloprid, and seasonally clothianidin, were driven by wastewater effluent, whereas thiamethoxam and imidacloprid urea were primarily from upstream non-point sources (or potential in-stream transformation for imidacloprid urea). This is the first study to quantify neonicotinoid persistence in an effluent-dominated stream throughout the year-implicating wastewater effluent as a point-source for imidacloprid (year-round) and clothianidin (seasonal). These findings suggest possible overlooked neonicotinoid indoor human exposure routes with subsequent implications for instream ecotoxicological exposure.


Assuntos
Inseticidas , Animais , Guanidinas , Humanos , Inseticidas/análise , Invertebrados , Neonicotinoides , Tiametoxam , Águas Residuárias
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