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1.
Environ Monit Assess ; 192(9): 595, 2020 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-32827100

RESUMO

Carbaryl (a carbamate insecticide) and cypermethrin (a synthetic pyrethroid insecticide) are extensively used in agriculture. However, the presence of these insecticides in the environment constitutes a significant source of ecological contamination. This study determined the levels of these insecticides in Lisungwi, Neno District, a cotton-growing area in Southern Malawi. A total of 81 soil samples (500 g each) were collected from six sampling points (33 in dry season and 48 rainy season). A total of 86 water samples (500 ml each) were collected seasonally (20 from shallow wells, 18 from streams, and 48 from boreholes). High-performance liquid chromatography (HPLC) was used to determine carbaryl while UV/Vis spectrophotometer detected cypermethrin. Paired t test showed a significant (p < 0.05) difference between rainy season carbaryl (in water and soil) and maximum recommended levels (MRL) (Canadian guidelines and Australian Guidelines). Similarly, a significant (p < 0.05) difference between carbaryl and WHO limits and US MRL was reported in water and soil during the rainy season. A similar observation was made for cypermethrin. Specifically, carbaryl (0.083-0.254 mg/L in surface water and 0.165-0.492 mg/L in groundwater) and cypermethrin (8.115-15.460 mg/L in surface water and 4.48-12.18 mg/L in groundwater) concentrations during the rainy season were above the recommended limits. On the other hand, cypermethrin (0.01-0.048 mg/L) in the soil samples during the rainy season was below the recommended limits while carbaryl (1.67-1.305 mg/L) was above the recommended limits. Higher carbaryl and cypermethrin values were recorded during the rainy season than the dry season. Nitrate, pH, and EC and the insecticides (carbaryl and cypermethrin) depicted strong correlation and significance (p < 0.05), suggesting that these factors influenced their persistence in both soil and water. The study provides evidence that Lisungwi has cypermethrin and carbaryl concentrations above the recommended limits and their presence varies with seasons-a situation considered to be a serious threat to both aquatic biota and humans.


Assuntos
Inseticidas/análise , Piretrinas/análise , Austrália , Canadá , Carbaril , Monitoramento Ambiental , Humanos , Malaui , Solo , Água
2.
J Chromatogr A ; 1623: 461204, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505292

RESUMO

Deep eutectic solvents (DESs) were used as an extractant for the determination of pyrethroids in environmental water and tea beverage samples. Three different acids were chosen as hydrogen bond donors for preparation of DESs, and decanoic acid was optimal because of its high recovery. Factors affecting relative recovery were optimized individually, including salt addition, surfactant addition, extraction temperature, DES amount, and sample volume etc. Under the optimized experimental conditions, the relative recovery of pyrethroids was from 89.3% to 97.7%, with relative standard deviation (RSD) values ranging from 1.75% to 2.73%. The linear correlation coefficient ranged from 0.9981 to 0.9992, and the linear range was between 1.9 and 500 µg/L. Based on a signal-to-noise ratio (S/N) of 3:1, the limit of detection (LOD) values were 0.56 to 1.24 µg/L. The enrichment factor ranged from 92 to 105. In conclusion, good extraction efficiency was achieved in tea beverage samples under the optimized conditions.


Assuntos
Bebidas , Emulsões/química , Interações Hidrofóbicas e Hidrofílicas , Microextração em Fase Líquida/métodos , Piretrinas/análise , Solventes/química , Chá/química , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Cloreto de Sódio/química , Tensoativos/química , Temperatura , Água/química
3.
Environ Monit Assess ; 192(5): 273, 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32266493

RESUMO

An accurate and sensitive dispersive liquid-liquid microextraction method based on binary solvents was used to enrich prothiofos, oxadiargyl, and gamma-cyhalothrin for quantification by GC-MS. The combination of two extraction solvents (binary mixture) resulted in higher extraction efficiencies compared to the single solvent extraction systems. Parameters of the binary extraction method where optimized to enhance the extraction output of the analytes. The limits of detection calculated for the analytes ranged between 0.59 and 1.6 ng/mL. Linear calibration plots of the analytes covered wide concentration ranges with R2 values greater than 0.9996 and percent relative standard deviation lower than 10%. Spiked recovery experiments were performed well and wastewater at two different concentrations and satisfactory results (89-104%) were obtained. The binary solvent microextraction method was combined with QuEChERS to quantify the analytes in pineapple matrix, using matrix matching method to enhance the accuracy of the method to almost 100%.


Assuntos
Microextração em Fase Líquida , Poluentes Químicos da Água , Ananas/química , Monitoramento Ambiental , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Nitrilos/análise , Organotiofosfatos/análise , Oxidiazóis/análise , Piretrinas/análise , Solventes , Água/química
4.
J Chromatogr A ; 1620: 461007, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32151417

RESUMO

Evaluation of chiral pesticides remains a frequently neglected matter in routine food control laboratories. This fact is due to the existence of many residue definitions but also due to the lack of robust instrumental methods for the evaluation of these isomeric compounds. However, supercritical fluid chromatography coupled to mass spectrometry (SFC-ESI-MS/MS) has been demonstrated to perform fast and highly efficient separations without the need to change the mobile phase employed in multiresidue pesticide analyses. Regarding chiral stationary phase columns, the polysaccharide-based ones clearly demonstrate the best separation technology. Two polysaccharide-based columns were tested in this study, and the robustness of their combination with SFC was verified. The enantiomers of lambda-cyhalothrin and metalaxyl were studied precisely due to their markedly distinct toxicity and enantioselectivity. Furthermore, the acute reference dose for gamma-cyhalothrin is half in comparison with its enantiomer (0.0025 and 0.005 mg/kg respectively), which is present in the lambda-cyhalothin residue definition. These enantiomers were analyzed in terms of linearity, reproducibility, and matrix effects in four representative matrices (tomato, orange, leek, and cayenne). Additionally, field tests under greenhouse conditions for these compounds were performed. The results obtained after different sample collections revealed a similar degradation in lambda-cyhalothrin enantiomers (R, S, S, and S, R, R) but not in the case of metalaxyl-M (mefenoxam) where the degradation in tomato was 2 to 6 times less in comparison with its S-enantiomer.


Assuntos
Alanina/análogos & derivados , Cromatografia com Fluido Supercrítico/métodos , Nitrilos/análise , Praguicidas/análise , Piretrinas/análise , Alanina/análise , Alanina/química , Nitrilos/química , Praguicidas/química , Polissacarídeos/química , Piretrinas/química , Reprodutibilidade dos Testes , Estereoisomerismo , Espectrometria de Massas em Tandem
5.
Food Chem ; 319: 126539, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32193060

RESUMO

Two molecularly imprinted microspheres and two fluorescent tracers for benzimidazoles and pyrethroids were synthesized respectively. The two types of microspheres were coated in the wells of conventional microplate simultaneously. Then the sample extracts and the two traces were added for differential competition. The fluorescence intensities at two different emission wavelengths were excited and recorded for quantification of the two classes of drugs respectively. The optimized multiplexed fluorescence method could be used to determine 8 benzimidazoles and 10 pyrethroids in mutton and beef samples simultaneously. The limits of detection of the method for the 18 drugs were in the range of 5.2-17 ng/mL, and the recoveries from the standards fortified blank samples were in the range of 67.7%-109%. From the analysis of 60 real mutton and beef samples, this method could be used for multi-screening the residues of benzimidazoles and pyrethroids in meat samples.


Assuntos
Benzimidazóis/análise , Piretrinas/análise , Carne Vermelha/análise , Animais , Benzimidazóis/química , Fluorescência , Microesferas , Impressão Molecular , Estrutura Molecular , Piretrinas/química
6.
J Environ Sci Health B ; 55(6): 517-524, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32065572

RESUMO

The current study estimated the dissipation rates of abamectin, chlorfenapyr and pyridaben acaricides in pods of green beans (Phaseolus vulgaris L.) under field conditions in Egypt. Pesticides were extracted and cleaned-up by QuEChERS method and were analyzed by HPLC. The dissipation of these acaricides followed the first order kinetics model with half-life (t1/2) values 1.00, 3.50 and 1.50 days for abamectin, chlorfenapyr and pyridaben, respectively. The lowest residues, at different time intervals of field application rate of each pesticide, were observed with abamectin followed by pyridaben and then chlorfenapyr. Pre-harvest intervals (PHIs) were 10.00, 13.50 and 6.00 days for abamectin, chlorfenapyr and pyridaben, respectively and were below the established European maximum residue limits (EU MRLs) 10-14, 14-21 and 7-10 days after application, respectively. If the fresh pods will be consumed after harvest, it is expected that the presence of these pesticides in the food will have a negative impact on human health. Therefore, the elimination of the residues of these harmful pesticides must be carried out.


Assuntos
Acaricidas/farmacocinética , Ivermectina/análogos & derivados , Phaseolus/efeitos dos fármacos , Piretrinas/farmacocinética , Piridazinas/farmacocinética , Acaricidas/análise , Fracionamento Químico , Cromatografia Líquida de Alta Pressão , Egito , Contaminação de Alimentos/análise , Humanos , Ivermectina/análise , Ivermectina/farmacocinética , Cinética , Resíduos de Praguicidas/análise , Phaseolus/metabolismo , Piretrinas/análise , Piridazinas/análise
7.
J Chromatogr A ; 1619: 460929, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32008821

RESUMO

A simple, green and efficient method for extraction, purification and enrichment of pesticide residues of triazoles and pyrethroids in Longan fruit was developed by ultrasonic-assisted aqueous two-phase extraction (UAATPE) coupled to vortex-assisted dispersive liquid-liquid microextraction (VADLLME). Using an aqueous two-phase system (ATPS) of ethanol/K2HPO4 as extraction solvent, the composition of the ATPS, extraction temperature and time were investigated, respectively. Then VADLLME process also was optimized by investigating type and volume of extracting and dispersive solvents, vortex-assisted time and salt addition. The optimum conditions were as follows: the ATPS composition of ethanol concentration 30.0% (w/w) and K2HPO4 concentration 25% (w/w), extraction temperature 70 °C and extraction time 15 min for UAATPE; 1-dodecanol 200 µL as extraction solvent, ethanol 1.25 mL as dispersive solvent, vortex-assisted time 1.5 min and addition of NaCl 4% (w/v) for VADLLME. Ethanol as extraction solvent and dispersive solvent could directly connect UAATPE with VADLLME without extra steps. By means of HPLC-DAD detection, nine pesticides had good linearity ranged from 0.0200 to 13.59 µg/mL (R2 ≥ 0.9957). LODs and LOQs were in the range of 0.005576-0.01740 µg/mL and 0.01859-0.05010 µg/mL, respectively. UAATPE-VADLLME coupled to HPLC was successfully applied to simultaneous determination of multiple pesticides in Longan fruit, and mean recoveries and RSDs were between 76.95% and 98.63%, 1.2% and 9.8%, respectively. Furthermore, myclobutanil, fenpropathrin and deltamethrin were detected in pericarp and pulp of Longan samples from different districts, respectively.


Assuntos
Cromatografia Líquida de Alta Pressão , Análise de Alimentos/métodos , Frutas/química , Resíduos de Praguicidas/isolamento & purificação , Sapindaceae , Poluentes Químicos da Água/isolamento & purificação , Limite de Detecção , Microextração em Fase Líquida/métodos , Resíduos de Praguicidas/análise , Piretrinas/análise , Piretrinas/isolamento & purificação , Solventes/química , Triazóis/análise , Triazóis/isolamento & purificação , Ultrassom , Água/análise , Poluentes Químicos da Água/análise
8.
Chemosphere ; 244: 125507, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31835049

RESUMO

Agricultural and household applications of pyrethroid insecticides have significantly increased residual concentrations in living cells and environments. The enhanced concentration is toxic for living beings. Pyrethroid hydrolase enzyme (pyrethroid catalyzing esterase) regulates pyrethroid degradation, and has been well reported in various organisms (bacteria, fungi, insects and animals). Hydrolysis mechanisms of these esterases are different from others and properly function at factors viz., optimum temperature, pH and physicochemical environment. Active site of the enzyme contains common amino acids that play important role in pyrethroid catalysis. Immobilization technology emphasizes the development of better reusable efficiency of pyrethroid hydrolases to carry out large-scale applications for complete degradation of pyrethroids from the environments. In this review we have attempted to provide insights of pyrethroid-degrading esterases in different living systems along with complete mechanisms.


Assuntos
Biodegradação Ambiental , Esterases/metabolismo , Inseticidas/metabolismo , Piretrinas/metabolismo , Animais , Hidrolases , Hidrólise , Insetos , Inseticidas/análise , Piretrinas/análise , Temperatura
9.
J Chromatogr A ; 1613: 460660, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-31685247

RESUMO

Pyrethrum extract is a natural insecticide that has been used worldwide for centuries, with pyrethrins being considered active ingredients. Their purification is difficult due to their chemical structural similarity and instability to light. In the present study, a coordination complex high-speed counter-current chromatography was used to separate pyrethrins from pyrethrum extract. The two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water (10:2:10:2, v/v/v/v) with 0.30 mol/L silver nitrate was selected for separation. As a result, five pyrethrins including cinerin II (31.2 mg), pyrethrin II (43.9 mg), jasmalin II (39.1 mg), pyrethrin I (32.4 mg), and jasmalin I (16.0 mg) were obtained from 400 mg crude extract in 6 h by one-step HSCCC separation, with purities over 95%. The isolated compounds were identified by MS, 1H-NMR and 13C-NMR spectroscopy. The results demonstrated that the addition of silver nitrate in the two-phase solvent system of HSCCC significantly increased the HSCCC separation factor of pyrethrins. HSCCC is a rapid method for purification of pyrenthrins from pyrethrum extract. The established method may also be applied to separate analogous compounds from natural products in which the chemical structure differs in the position or numbers of alkenes.


Assuntos
Chrysanthemum/química , Distribuição Contracorrente/métodos , Piretrinas/isolamento & purificação , Nitrato de Prata/química , Flores/química , Extratos Vegetais/química , Piretrinas/análise
10.
Food Chem ; 306: 125640, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31606625

RESUMO

Combination of pesticides; acetamiprid, flutolanil and etofenprox are usually used for tomato fruits for protecting them against pest infection. Generally, pesticides, residues could be one of the health hazard sources. Two specific simple sensitive chromatographic methods are developed for simultaneous estimation of the concerning pesticides' residues using simple economic steps of field sample preparation. The first method is HP- TLC method. Hexane: methanol: acetone: glacial acetic acid (8:2:0.5:0.1, by volume) is proposed as a developing system. The second one is RP- HPLC. Acetonitrile: water (75:25, v/v) is proposed as a mobile phase. The recommended methods are completely validated regarding ICH guidelines. Their means percentages and standard deviations of accuracy range 100.32 ±â€¯0.89 to 99.27 ±â€¯0.9. The methods' repeatability and intermediate precision relative standard deviation percentages range 0.395-0.894. They are successfully applied for estimating the pesticides in pure and commercial forms and field samples.


Assuntos
Manipulação de Alimentos , Lycopersicon esculentum/química , Resíduos de Praguicidas/análise , Piretrinas/análise , Cromatografia Líquida de Alta Pressão/métodos , Frutas/química , Segurança
11.
Ecotoxicol Environ Saf ; 188: 109876, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31704319

RESUMO

This study aimed to assess the levels of pyrethroids and organochlorine residues in the tissues of cultured Mugil capito and in water samples obtained from three different sites (Al-Hamol, Al-Riad and Sidi Salem; referred to as Area 1, Area 2, and Area 3, respectively) in the Delta region, Egypt. The study also assessed the biochemical markers in exposed mullet and evaluated the impact of these residues on the expression of insulin-like growth factor 1 (IGF-1) in muscle and cytochrome P4501A (CYP1A) in liver tissues using qRT-PCR and SDS-PAGE methods. The results revealed that pesticide residue levels in the water were variable, but were lower than detected levels in fish. Significant (P < 0.05) differences were found across the three study areas in terms of serum ALT, but the serum AST level was not significantly (P > 0.05) elevated in all study regions. Serum creatinine and urea levels were significantly (P < 0.05) elevated in area 3. Furthermore, glutathione and malondialdehyde concentrations significantly increased (P < 0.05) in liver tissues in area 3. Using the qRT-PCR technique, the results revealed that the expression level of IGF-1 was most significant in area 3, while the expression level of CYP1A was most significant in area 1. The protein profile showed some differences in band numbers and molecular weights of protein bands across different regions. Overall, the alteration in biochemical parameters revealed pesticide interference with the metabolic processes of fish. Furthermore, the pesticide pollution had an effect on the expression of IGF-1 and CYP1A genes and led to changes in the protein profile. Therefore, these markers can be used to monitor fish distress following exposure to the pollutant.


Assuntos
Família 1 do Citocromo P450/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Hidrocarbonetos Clorados/toxicidade , Fator de Crescimento Insulin-Like I/genética , Proteínas Musculares/metabolismo , Piretrinas/toxicidade , Smegmamorpha/metabolismo , Animais , Aquicultura , Egito , Biomarcadores Ambientais/genética , Hidrocarbonetos Clorados/análise , Hidrocarbonetos Clorados/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Proteínas Musculares/química , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/metabolismo , Resíduos de Praguicidas/toxicidade , Piretrinas/análise , Piretrinas/metabolismo , Alimentos Marinhos/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo
12.
Food Chem ; 309: 125755, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31704075

RESUMO

A simple, sensitive and environmentally-friendly method for determining organophosphorus and pyrethroid pesticides in vegetables was developed to better evaluate the risk of consuming them. The pesticides in vegetables were extracted, purified and concentrated by using the QuEChERS (quick, easy, cheap, effective, rugged and safe method) combined DLLME-SFO (dispersive liquid-liquid microextraction based on solidification of floating organic droplet) techniques. The key parameters were optimized through orthogonal array experimental design and statistical analysis. The linearity of the calibration curves was satisfied in matrix-matched standard solution with R2 ≥ 0.99. The limits of detection and limits of quantification were 0.3-1.5 and 0.9-4.7 µg/kg, respectively. The average recoveries of pesticides were 61.6-119.4% with relative standard deviations <16.1%. Furthermore, the method was applied successfully to analyse the pesticides in 15 pairs of organic and conventional vegetables. These results reflect the efficiency, reliability and robustness of the developed method.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Líquida/métodos , Compostos Organofosforados/análise , Praguicidas/análise , Piretrinas/análise , Verduras/química , Calibragem , Cromatografia Gasosa-Espectrometria de Massas/normas , Limite de Detecção , Compostos Organofosforados/isolamento & purificação , Compostos Organofosforados/normas , Praguicidas/isolamento & purificação , Praguicidas/normas , Piretrinas/isolamento & purificação , Piretrinas/normas , Reprodutibilidade dos Testes , Temperatura , Verduras/metabolismo
13.
Sci Total Environ ; 701: 134916, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31726407

RESUMO

A national-scale survey was conducted to assess the levels and distribution of two extensively used pesticides (pyrethroids and atrazine) in greenhouse and open-field soils in 20 provinces across China. Concentrations between 1.30 and 113 ng/g and 0.51-85.4 ng/g for the total pyrethroids (PYs) and of LOD-137 ng/g and LOD-134 ng/g for atrazine were found in greenhouse and open-field soils, respectively. Higher contaminations were found in the greenhouse than in the open fields. The levels of total pyrethroids in 80% of the greenhouses and of atrazine in 60% of the greenhouses were significantly higher than those in the nearby open-field soils (p < 0.05), respectively. The contamination of PYs and atrazine was generally more serious in the northern provinces of China, such as Heilongjiang, Jilin, Liaoning, Beijing, and Hebei. Pearson correlation analysis revealed that the contamination of PYs was significantly correlated with the soil total organic carbon (TOC) value in both greenhouse and open-field soils. Canonical correspondence analysis (CCA) showed that PYs might have an impact on the microbial alpha diversity, while cyhalothrin and cypermethrin may be the key factors affecting the microbial community in the greenhouse and open-field soils. The soil samples containing pesticide residues showed distinct taxonomic and functional communities, where an increased diversity and abundance of microorganisms able to degrade pesticides was observed with high-level PYs contamination. These findings provide useful information for evaluating PYs and atrazine pollution and for contamination management in greenhouse agriculture.


Assuntos
Atrazina/análise , Monitoramento Ambiental , Praguicidas/análise , Piretrinas/análise , Poluentes do Solo/análise , Agricultura , China , Resíduos de Praguicidas/análise , Solo/química
14.
SAR QSAR Environ Res ; 31(1): 19-32, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31718305

RESUMO

In the present work, an existing vegetation/air/litter/soil model (SoilPlusVeg) was modified to improve organic chemical fate description in terrestrial/aquatic ecosystems accounting for horizontal and vertical particulate organic carbon (POC) transport in soil. The model was applied to simulate the fate of three pesticides (terbuthylazine, chlorpyrifos and etofenprox), characterized by increasing hydrophobicity (log KOW from about 3 to 7), in the soil compartment and more specifically, their movement towards surface and groundwater through infiltration and runoff processes. The aim was to evaluate the role of dissolved organic carbon (DOC) and POC in the soil in influencing the peak exposure of pesticides in terrestrial/aquatic ecosystems. Simulation results showed that while terbuthylazine and chlorpyrifos dominated the free water phase (CW-FREE) of soil, etofenprox was mainly present in soil porewater as POC associated chemical. This resulted in an increase of this highly hydrophobic chemical movement towards groundwater and surface water, up to a factor of 40. The present work highlighted the importance of DOC and POC as an enhancer of mobility in the water of poor or very little mobile chemicals. Further studies are necessary to evaluate the bioavailability change with time and parameterize this process in multimedia fate models.


Assuntos
Carbono/química , Herbicidas/análise , Inseticidas/análise , Material Particulado/química , Poluentes do Solo/análise , Clorpirifos/análise , Clorpirifos/química , Herbicidas/química , Interações Hidrofóbicas e Hidrofílicas , Inseticidas/química , Modelos Teóricos , Piretrinas/análise , Piretrinas/química , Relação Quantitativa Estrutura-Atividade , Poluentes do Solo/química , Triazinas/análise , Triazinas/química
15.
Ecotoxicol Environ Saf ; 190: 110101, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31874407

RESUMO

Varroa mites often inflict heavy losses on the global bee industry and there are few effective control options. Among these methods to control mites, pesticides are extensively used as a cheap, easy to use, and high-efficiency control measure. However, bees are sensitive to many pesticides; thus, a balance between losses induced by drugs and maximum benefits are important for beekeeping and risk assessment. In this study, the effects of flumethrin, a pyrethroid miticide used on bee colonies, was evaluated using bee larvae reared in vitro. We found that flumethrin induced significant mortality during larval metamorphosis and adult emergence. After continuous exposure during the larval stage, significant changes were observed in antioxidative enzymes (SOD and CAT), lipid peroxidation (MDA, LPO, and POD), and detoxification enzymes (GSH, GST, and GR) in the late instar larvae before pupation. It is also noteworthy that flumethrin significantly regulated the expression of immune (Basket and Dscam) and developmental (Amems, Amhex10869, Vtg and Mfe) genes in larvae, which influences can also be found in the subsequent pupae and adult stages. These findings indicate that flumethrin itself is toxic to bee larvae and has potential risks during colony development. Bees are important pollinators and the sustainable and healthy development of colonies is the foundation of pollinating success for agricultural production. This study would provide some useful thinking for pesticides application techniques and processes in risk assessment of pesticides to bee larvae, even colony.


Assuntos
Abelhas/fisiologia , Praguicidas/toxicidade , Piretrinas/toxicidade , Estresse Fisiológico , Animais , Criação de Abelhas , Mel , Larva/efeitos dos fármacos , Praguicidas/análise , Polinização , Pupa/crescimento & desenvolvimento , Piretrinas/análise , Varroidae
16.
Anal Chim Acta ; 1090: 72-81, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31655648

RESUMO

In this study, a novel multiwalled carbon nanotubes/polyaniline-polypyrrole@polydimethylsiloxane (MWCNTs/PANI-PPy@PDMS) fiber was prepared by a facile electrodeposition strategy followed by polymer surface modification, and used as the sorbent of in vivo solid phase microextraction (in vivo SPME). The custom-made fiber exhibits better enrichment capacity than three commercial SPME fibers. Ultra-high enrichment factor (438-2659), satisfactory thermal and mechanical stability, excellent matrix-compatibility and anti-biofouling ability render the fiber attractive as in vivo sampling probe. Combining in vivo SPME with gas chromatography-mass spectrometry (GC-MS), a convenient and sensitive method was successfully developed for the rapid determination of pesticides (hexachlorobenzene, chlorothalonil, fipronil, chlorfenapyr) in garlic. Under the optimal conditions, the proposed method displays relatively wide linear range (three or four orders of magnitude) with a coefficient of determination above 0.9944 both in the standard solution and spiked homogenized garlic samples, respectively. Low detection limits from 0.38 to 1.90 ng g-1 were obtained in homogenized garlic samples. Relative standard deviations (RSDs) less than 15.5% and recovery between 84.0% and 108.2% indicate satisfactory precision and accuracy of the method. In summary, a promising non-lethal method based on in vivo SPME-GC-MS is developed in this study, which provides a green, efficient, economic and rapid strategy for the determination of trace pesticide residues in edible plants.


Assuntos
Alho/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Resíduos de Praguicidas/análise , Microextração em Fase Sólida/métodos , Adsorção , Compostos de Anilina/química , Dimetilpolisiloxanos/química , Hexaclorobenzeno/análise , Limite de Detecção , Nanotubos de Carbono/química , Nitrilos/análise , Polímeros/química , Pirazóis/análise , Piretrinas/análise , Pirróis/química
17.
J Agric Food Chem ; 67(41): 11536-11541, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31589045

RESUMO

Limited reports on the use of nanobodies (Nbs) in fluorescence polarization immunoassay (FPIA) aroused us to explore if the small size of Nbs is a drawback for the development of sensitive FPIA to small molecular compounds, particularly since FPIA is a technology strongly dependent on molecular weight. In the present work, three different molecular weight Nbs against 3-phenoxybenzoic acid (3-PBA), an exposure biomarker of pyrethroid insecticides, including bare Nbs (15 kDa), Nbs-Avidin (Nbs-AV, 60 kDa), and Nbs-Alkaline phosphatase (Nbs-AP, 130 kDa) were specifically generated to cover distinct regions on the polarization and molecular weight relationship curve for a fluorescein tracer. In competitive FPIA, similar half-maximal inhibitory concentrations (IC50) of 3-PBA of 16.4, 12.2, and 14.8 ng mL-1 were obtained for Nbs, Nbs-AV, and Nbs-AP, respectively, indicating that the size of Nbs in the range tested had no significant effect on the sensitivity of the resulting competitive FPIA. An IC50 of 20.2 ng mL-1 for an anti-3-PBA polyconal antibody based FPIA further demonstrated the performance of Nbs, which was comparable to that of traditional antibodies in FPIA. Spike-recovery studies showed good and reproducible recovery of 3-PBA in urine samples, demonstrating the applicability of Nb-based FPIA. Overall, our results show that Nb-based FPIA achieves sensitivity levels of FPIA based on conventional antibodies and further indicate that Nb absolutely meets the sensitivity requirement of FPIA.


Assuntos
Benzoatos/urina , Imunoensaio de Fluorescência por Polarização/métodos , Inseticidas/toxicidade , Piretrinas/toxicidade , Anticorpos de Domínio Único/química , Biomarcadores/urina , Exposição Ambiental/análise , Imunoensaio de Fluorescência por Polarização/instrumentação , Humanos , Inseticidas/análise , Piretrinas/análise , Sensibilidade e Especificidade
18.
Artigo em Inglês | MEDLINE | ID: mdl-31569507

RESUMO

Alpha-cypermethrin is a synthetic pyrethroid that was extensively used for insect control, since the early 1980s. However, it is known that its presence in the environment has toxic effects on humans and aquatic life forms. For this reason, it is commendable for it to be removed completely from the contaminated environment. In this study, we evaluated the adsorption capacity of a marine alga for the removal of cypermethrin from water. The adsorption experiments were performed based on the batch equilibrium technique. The samples containing the pesticide were analyzed using gas chromatography with an electron capture detector, after liquid-liquid extraction in hexane. The results obtained from the kinetic adsorption studies showed that the equilibrium time was attained after 40 min. The adsorption parameters at equilibrium concentrations, obtained through the Langmuir, Freundlich, and Temkin models, showed that the used brown marine alga has a maximum amount of adsorbed cypermethrin of 588.24 µg/g. The correlation coefficients obtained for each model prove that the Langmuir model best fits the experimental data.


Assuntos
Recuperação e Remediação Ambiental/métodos , Fucus/metabolismo , Piretrinas/análise , Poluentes Químicos da Água/análise , Poluição Química da Água/prevenção & controle , Purificação da Água/métodos , Adsorção , Biodegradação Ambiental , Cinética
19.
Environ Pollut ; 254(Pt A): 112931, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31377335

RESUMO

Pyrethroids are a class of widely-used insecticides that can be transported from terrestrial applications to aquatic systems via runoff and tend to sorb to organic carbon in sediments. Pyrethroid occurrence is detrimental to stream ecosystems due to toxicity to sediment-dwelling invertebrates which are particularly at risk of pyrethroid exposure in urban streams. In this work, 49 streams located in watersheds in the northeastern United States were surveyed for nine current-use pyrethroids using two extraction methods. Total sediment concentrations were determined by exhaustive chemical extraction, while bioaccessible concentrations were determined by single-point Tenax extraction. Total and bioaccessible pyrethroid concentrations were detected in 76% and 67% of the sites, and the average sum of pyrethroids was 232 ng/g organic carbon (OC) for total and 43.8 ng/g OC for bioaccessible pyrethroids. Bifenthrin was the most commonly detected pyrethroid in streambed sediments. Sediment toxicity was assessed using 10-d Hyalella azteca bioassays, and 28% and 15% of sediments caused a decrease in H. azteca biomass and survival, respectively. A temperature-based focused toxicity identification evaluation was used to assess pyrethroids as the causal factor for toxicity. The concentrations of pyrethroids was only weakly correlated with the degree of urban land use. Sediment toxicity was predicted by total and bioaccessible pyrethroid concentrations expressed as toxic units. This work suggests that bioaccessibility-based methods, such as Tenax extraction, can be a valuable tool in assessing sediment toxicity.


Assuntos
Monitoramento Ambiental , Sedimentos Geológicos/química , Inseticidas/toxicidade , Piretrinas/toxicidade , Poluentes Químicos da Água/toxicidade , Anfípodes , Animais , Biomassa , Ecossistema , Inseticidas/análise , Invertebrados , New England , Polímeros , Piretrinas/análise , Rios , Inquéritos e Questionários , Estados Unidos , Poluentes Químicos da Água/análise
20.
Sci Total Environ ; 687: 712-719, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31412474

RESUMO

To assess the health risk posed by flumethrin residues in beeswax to honeybees and honey consumers, 124 wax samples randomly distributed in Belgium were analysed for flumethrin residues using liquid chromatography/tandem mass spectrometry. The risk posed by flumethrin residues in beeswax to honeybee health was assessed through the calculation of a non-pondered and a pondered Hazard Quotient by the prevalence rate of flumethrin considering an oral or topical exposure. No statistical difference was found when comparing both the average flumethrin residues concentrations and contact and oral pondered hazard quotients between apiaries with lower and equal or higher than 10% of colony loss. Flumethrin residues estimated daily intake by Belgian consumers through honey and wax ingestion was estimated via a deterministic (worst-case scenario) and a probabilistic approach. The probabilistic approach was not possible for beeswax consumption due to the lack of individual consumption data. The highest estimated exposure was <0.1% of the theoretical maximum daily intake for both approaches, meaning no risk for human health.


Assuntos
Exposição Dietética/análise , Resíduos de Praguicidas/análise , Piretrinas/análise , Ceras/química , Animais , Abelhas , Bélgica , Exposição Dietética/estatística & dados numéricos , Humanos
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