Pesticide residues in honey bee (Apis mellifera) pollen collected in two ornamental plant nurseries in Connecticut: Implications for bee health and risk assessment.

Honey bees (Apis mellifera L.) are one of the most important managed pollinators of agricultural crops. While potential effects of agricultural pesticides on honey bee health have been investigated in some settings, risks to honey bees associated with exposures occurring in the plant nursery setting have received little attention. We sought to identify and quantify pesticide levels present in honey bee-collected pollen harvested in two ornamental plant nurseries (i.e., Nursery A and Nursery B) in Connecticut. From June to September 2018, pollen was collected weekly from 8 colonies using bottom-mounted pollen traps. Fifty-five unique pesticides (including related metabolites) were detected: 24 insecticides, 20 fungicides, and 11 herbicides. Some of the pesticide contaminants detected in the pollen had not been applied by the nurseries, indicating that the honey bee colonies did not exclusively forage on pollen at their respective nursery. The average number of pesticides per sample was similar at both nurseries (i.e., 12.9 at Nursery A and 14.2 at Nursery B). To estimate the potential risk posed to honey bees from these samples, we utilized the USEPA's BeeREX tool to calculate risk quotients (RQs) for each pesticide within each sample. The median aggregate RQ for nurse bees was 0.003 at both nurseries, well below the acute risk level of concern (LOC) of ≥0.4. We also calculated RQs for larvae due to their increased sensitivity to certain pesticides. In total, 6 samples had larval RQs above the LOC (0.45-2.51), resulting from the organophosphate insecticide diazinon. Since 2015, the frequency and amount of diazinon detected in pollen increased at one of our study locations, potentially due to pressure to reduce the use of neonicotinoid insecticides. Overall, these data highlight the importance of considering all life stages when estimating potential risk to honey bee colonies from pesticide exposure.

Urinary metabolites of diazinon and chlorpyrifos in sprayer operators and farm workers of a potato farm.

In order to investigate the effect of diazinon and chlorpyrifos on agricultural workers exposed to pesticides, urinary metabolites 2-Isopropyl-6-methyl-4-pyrimidinol (IMPy) and 3,5,6-Trichloro-2-pyridinol (TPCy) in farm workers, sprayer operators, and non-exposed people as a control group were measured. The modified QuEChERS method was applied to extract samples and was measured using a gas chromatograph/nitrogen-phosphorus detector. The obtained results showed that the median concentrations of TCPy were 36.92-547.7 and 7.7-49.58 ng/mL for sprayer operators and farm workers, respectively. Moreover, the median concentrations of IMPy were 81.66-593.1 ng/mL for sprayer operators and 40.6-66.1 ng/mL for farm workers. The control group had no measurable metabolites. The IMPy level of 60% of sprayer operators was significantly higher (P ˂ 0.05) than the TCPy level. The analysis of variance highlighted the significant relationship (P ˂ 0.05) between the levels of each metabolite and the use of safety gloves, respiratory masks, safety goggles, working time per week, and type of insecticide exposure. Our findings revealed the need to measure the urinary metabolites of these insecticides in other exposed workers. Also, workers should be taught the impact of using personal protective equipment.

A modified quick-easy-cheap-effective-rugged-and-safe method involving carbon nano-onions-based dispersive solid-phase extraction and dispersive liquid-liquid microextraction for pesticides from grapes.

A combination of modified quick easy cheap effective rugged and safe extraction approach with carbon nano-onions-based dispersive solid-phase extraction and dispersive liquid-liquid microextraction was developed for the extraction of several pesticides (diazinon, chlorpyrifos, tebuconazole, deltamethrin, permethrin, haloxyfop-methyl, penconazole, and cyhalothrin) from grape before their analysis by gas chromatography-flame ionization detection. In the extraction approach, an aliquot of grape sample is chopped and after separating its juice, the pesticides that remained in the refuse are extracted by the quick, easy, cheap, effective, rugged, and safe extraction method. The obtained acetonitrile phase is mixed with juice and the analytes are extracted by the carbon nano-onions-based dispersive solid-phase extraction. The analytes are concentrated using the microextraction procedure to obtain high enrichment factors. The results showed low limits of detection (0.5-1.6 ng/g) and quantification (1.8-5.4 ng/g) with satisfactory linearity of the calibration curves (determination coefficient, r2 ≥ 0.994). The precision of the developed method expressed as relative standard deviations was good (≤7.2%). The method provided high enrichment factors (350-410) and extraction recoveries (70-82%). Finally, seven grape samples were analyzed successfully.

Impact of Micronutrient Supplementation on Pesticide Residual, Acetylcholinesterase Activity, and Oxidative Stress Among Farm Children Exposed to Pesticides.

The present interventional study aimed to assess the impact of micronutrient supplementation on pesticide-residues concentrations, vitamins, minerals, acetylcholinesterase activity and oxidative stress among 129 farm children (9-12 years, n = 66 and 13-15 years, n = 63) involved in farming activities in Ranga Reddy district, Telangana, India. Our data showed the presence of five organophosphorus pesticide residues (chlorpyrifos, diazinon, malathion, monocrotophos, and phosalone) among children before-supplementation (both age-groups); while post-supplementation, only two pesticide residues (chlorpyrifos and diazinon) were detected indicating improved metabolic rate. Vitamin E, copper, magnesium and zinc levels were also improved in both the age-groups and manganese levels were significantly increased only among children of 13-15 years age group. Further, post-supplementation also showed an improvement in acetylcholinesterase activity and a decrease in lipid peroxidation among both the age groups of children. However, further research for ascertaining the ameliorating effect of micronutrients in preventing adverse effects of organophosphorus pesticides must be conducted.

Diazinon degradation by bacterial endophytes in rice plant (Oryzia sativa L.): A possible reason for reducing the efficiency of diazinon in the control of the rice stem-borer.

It is well known that microorganisms can reduce the effectiveness of organophosphate pesticides after their application. But, little information is available concerning the effect of rice endophytic bacteria on the degradation of diazinon, an organophosphate pesticide used in control of the rice stem-borer, absorbed by the rice plant. Thus, aim of this study was to characterize the endophytic bacterial isolates, isolated from diazinon-treated and non-treated rice plants in paddy fields, in terms of diazinon degradation and to investigate whether potent isolates that degrade diazinon in vitro might have the same effect in the rice plant. The results showed that all endophytic isolates, isolated from both groups of rice plants (diazinon-treated and non-treated rice plants), could grow in mineral salt medium (MSM) supplemented with diazinon (20 mg L-1) as a sole carbon source, and 3.79-58.52% of the initial dose of the insecticide was degraded by the isolates within 14 d of incubation. Phylogenetic analysis based on 16 S rRNA sequencing indicated that the potent isolates (DB26-R and B6-L) clearly belonged to the Bacillus genus. The diazinon concentrations in rice plants co-inoculated with B. altitudinis DB26-R and B. subtilis subsp. Inaquosorum B6-L and single-inoculated with these strains were reduced significantly compared with endophyte-free rice plants. These results provide unequivocal evidence that the rice endophytic bacteria, in addition to in vitro degradation of diazinon, are also involved in the rapid inactivation of diazinon in rice plants treated with diazinon (in vivo degradation of diazinon).

New magnetic graphene-based inorganic-organic sol-gel hybrid nanocomposite for simultaneous analysis of polar and non-polar organophosphorus pesticides from water samples using solid-phase extraction.

A new graphene-based tetraethoxysilane-methyltrimethoxysilane sol-gel hybrid magnetic nanocomposite (Fe3O4@G-TEOS-MTMOS) was synthesised, characterized and successfully applied in magnetic solid-phase extraction (MSPE) for simultaneous analysis of polar and non-polar organophosphorus pesticides from several water samples. The Fe3O4@G-TEOS-MTMOS nanocomposite was characterized using Fourier transform-infrared spectroscopy, energy-dispersive X-ray spectroscopy, field emission scanning electron microscopy and X-ray diffraction. Separation, determination and quantification were achieved using gas chromatography coupled with micro electron capture detector. Adsorption capacity of the sorbent was calculated using Langmuir equation. MSPE was linear in the range 100-1000 pg mL-1 for phosphamidon and dimethoate, and 10-100 pg mL-1 for chlorpyrifos and diazinon, with limit of detection (S/N = 3) of 19.8, 23.7, 1.4 and 2.9 pg mL-1 for phosphamidon, dimethoate, diazinon and chlorpyrifos, respectively. The LODs obtained is well below the maximum residual level (100 pg mL-1) as set by European Union for pesticides in drinking water. Acceptable precision (%RSD) was achieved for intra-day (1.3-8.7%, n = 3) and inter-day (7.6-17.8%, n = 15) analyses. Fe3O4@G-TEOS-MTMOS showed high adsorption capacity (54.4-76.3 mg g-1) for the selected OPPs. No pesticide residues were detected in the water samples analysed. Excellent extraction recoveries (83-105%) were obtained for the spiked OPPs from tap, river, lake and sea water samples. The newly synthesised Fe3O4@G-TEOS-MTMOS showed high potential as adsorbent for OPPs analysis.

Effect of hypochlorite oxidation on cholinesterase-inhibition assay of acetonitrile extracts from fruits and vegetables for monitoring traces of organophosphate pesticides.

A reproducible method for monitoring traces of cholinesterase (ChE) inhibitors in acetonitrile extracts from fruits and vegetables is described. The method is based on hypochlorite oxidation and ChE inhibition assay. Four common representative samples of produce were selected from a supermarket to investigate the effect of different matrices on pesticides recoveries and assay precision. The samples were extracted with acetonitrile to prepare them for ChE inhibition assays: if necessary, clean-up was performed using dispersive solid-phase extraction for gas chromatography-mass spectrometry (GC/MS) analyses. Chlorine was tested as an oxidising reagent for the conversion of thiophosphorus pesticides (P=S compounds) into their P=O analogues, which have high ChE-inhibiting activity. Chlorine consumption of individual acetonitrile extracts was determined and was strongly dependent on the individual types of fruits and vegetables. After treating the acetonitrile extracts with an excess hypochlorite at 25°C for 15 min, the ChE-inhibiting activities and detection limits for each chlorine-treated pesticide solution were determined. Matrix composition did not interfere significantly with the determination of the pesticides. Enhanced anti-ChE activities leading to low detection limits (ppb levels) were observed for the chlorine-treated extracts that were spiked with chlorpyrifos, diazinon, fenitrothion, and isoxathion. This combination of oxidative derivatisation and ChE inhibition assays was used successfully to monitor and perform semi-quantitative determination of ChE inhibitors in apple, tomato, cucumber, and strawberry samples.

Destructive adsorption of Diazinon pesticide by activated carbon nanofibers containing Al2O3 and MgO nanoparticles.

We report the destructive adsorption of Diazinon pesticide by porous webs of activated carbon nanofibers containing Al2O3 and MgO nanoparticles. The results show that, the presence of Al2O3 and MgO nanoparticles in the activated carbon nanofibers increases the amount of destructively adsorbed Diazinon pesticide by activated carbon nanofibers. Moreover, type, amount, and specific surface area of metal oxide nanoparticles affect the adsorption rate as well as the total destructively adsorbed Diazinon. Liquid chromatography proved the degradation of Diazinon by chemical reaction with Al2O3 and MgO nanoparticles. Liquid chromatography-mass spectrometry showed that the main product of reaction between Diazinon and the metal oxides is 2-isopropyl-6-methyl-4-pyrimidinol with less toxicity than Diazinon.

Simultaneous determination of parathion, malathion, diazinon, and pirimiphos methyl in dried medicinal plants using solid-phase microextraction fibre coated with single-walled carbon nanotubes.

A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r(2) ≥ 0.993) over the concentration ranges from 1.5 to 300 ng g(-1), and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g(-1). For parathion and malathion, the linear range and limit of detection were 2.5-300 (r(2) ≥ 0.991) and 0.5 ng g(-1), respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350 °C), and longer lifespan (over 250 times) than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples.

Evaluation of microwave-assisted extraction for the analysis of organophosphorus and pyrethroid pesticides in green onions.

The aim of this study was to evaluate the efficiency of microwave-assisted extraction (MAE) for the analysis of organophosphorus (OP) and pyrethroid (PYR) pesticides in green onions by GC/MS. We optimized MAE extraction solvent, temperature, and time by using a certified reference material. As a result, the concentrations of two OP and two PYR target pesticides obtained by MAE with acetonitrile at 110 degrees C for 10 min were in good agreement with certified concentrations and comparable to the results by homogenization used as reference extraction technique. When the recovery test, performed by spiking the target pesticides into blank samples (5.0 g), was carried out with our optimized MAE conditions, mean recoveries of 16 OP and 10 PYR pesticides were 72-108% for a 1.0 pg spiking level and 70-119% for a 0.2 microg level. These results were acceptable according to the validation guideline for testing method of agricultural chemicals in food by Ministry of Health, Labour, and Welfare in Japan. The results suggested that MAE can be used for the analysis of OP and PYR pesticides in green onions.

Reduction of diazinon and dimethoate in apple juice by pulsed electric field treatment.

BACKGROUND: Organophosphorus pesticides (OPPs) are widely used in agricultural production in China, and residues of OPPs in agro-products and foods have become a public health concern. Chronic exposure to OPPs can result in potential immunosuppressive effects, cytotoxicity and mutagenicity. Pulsed electric fields (PEFs) have the potential to be used as an alternative to conventional techniques of food production. The aim of the present study was to investigate the influence of PEFs on the degradation of diazinon and dimethoate added to apple juice. RESULTS: PEF treatment significantly promoted the degradation of both pesticides (P < 0.05). The extent of degradation was strongly influenced by the electric field strength and treatment time, and maximum degradation of both diazinon (47.6%) and dimethoate (34.7%) was achieved by treatment at 20 kV cm⁻¹ for 260 µs. The degradation behaviour of the pesticides was described by Weibull and Hülsheger models, both of which successfully fitted the degradation of diazinon and dimethoate. In addition, the decline in the toxicity of samples was observed with a photobacterium bioassay. CONCLUSION: PEF treatment was effective in eliminating residues of diazinon and dimethoate spiked in apple juice and in mitigating sample toxicity.

Residues of Pesticides in honeybee (Apis mellifera carnica) bee bread and in pollen loads from treated apple orchards.

Honey bee (Apis mellifera carnica) colonies were placed in two apple orchards treated with the insecticides diazinon and thiacloprid and the fungicide difenoconazole in accordance with a Protection Treatment Plan in the spring of 2007. Pollen and bee bread were collected from combs inside the hives. The residue of diazinon in pollen loads 10 days after orchard treatment was 0.09 mg/kg, and the same amount of residue was found in bee bread 16 days after treatment. In pollen loads 6 days after application 0.03 mg/kg of thiacloprid residues and 0.01 mg/kg of difenoconazole were found on the first day after application. Possible sub-lethal effects on individual honey bees and brood are discussed.

Biodegradation of the organophosphorus insecticide diazinon by Serratia sp. and Pseudomonas sp. and their use in bioremediation of contaminated soil.

An enrichment culture technique was used for the isolation of bacteria responsible for biodegradation of diazinon in soil. Three bacterial strains were screened and identified by MIDI-FAME profiling as Serratia liquefaciens, Serratia marcescens and Pseudomonas sp. All isolates were able to grow in mineral salt medium (MSM) supplemented with diazinon (50 mgL(-1)) as a sole carbon source, and within 14d 80-92% of the initial dose of insecticide was degraded by the isolates and their consortium. Degradation of diazinon was accelerated when MSM was supplemented with glucose. However, this process was linked with the decrease of pH values, after glucose utilization. Studies on biodegradation in sterilized soil showed that isolates and their consortium exhibited efficient degradation of insecticide (100mg kg(-1) soil) with a rate constant of 0.032-0.085d(-1), and DT(50) for diazinon was ranged from 11.5d to 24.5d. In contrast, degradation of insecticide in non-sterilized soil, non-supplemented earlier with diazinon, was characterized by a rate constant of 0.014d(-1) and the 7-d lag phase, during which only 2% of applied dose was degraded. The results suggested a strong correlation between microbial activity and chemical processes during diazinon degradation. Moreover, isolated bacterial strains may have potential for use in bioremediation of diazinon-contaminated soils.