Pesticides In Samples Research Articles

Water sampling techniques for continous monitoring of pesticides in water

Good ecological and chemical status of water represents the most important aim of the Water Framework Directive 2000/60/EC, which implies respect of water quality standards at the level of entire river basin (2008/105/EC and 2013/39/EC). This especially refers to the control of pesticide residues in surface waters. In order to achieve the set goals, a continuous monitoring program that should provide a comprehensive and interrelated overview of water status should be implemented. However, it demands the use of appropriate analysis techniques. Until now, the procedure for sampling and quantification of residual pesticide quantities in aquatic environment was based on the use of traditional sampling techniques that imply periodical collecting of individual samples. However, this type of sampling provides only a snapshot of the situation in regard to the presence of pollutants in water. As an alternative, the technique of passive sampling of pollutants in water, including pesticides has been introduced. Different samplers are available for pesticide sampling in surface water, depending on compounds. The technique itself is based on keeping a device in water over a longer period of time which varies from several days to several weeks, depending on the kind of compound. In this manner, the average concentrations of pollutants dissolved in water during a time period (time-weighted average concentrations, TWA) are obtained, which enables monitoring of trends in areal and seasonal variations. The use of these techniques also leads to an increase in sensitivity of analytical methods, considering that pre-concentration of analytes takes place within the sorption medium. However, the use of these techniques for determination of pesticide concentrations in real water environments requires calibration studies for the estimation of sampling rates (Rs). Rs is a volume of water per time, calculated as the product of overall mass transfer coefficient and area of the receiving phase exposed to the external environment, and it is substance specific.

Use of a versatile, easy, and rapid atmospheric monitor (VERAM) passive samplers for pesticide determination in continental waters.

The versatile, easy, and rapid atmospheric monitor (VERAM), a passive sampler device widely used for air monitoring, was evaluated as passive sampler for the determination of 23 pesticides in water. Gas chromatography with mass spectrometry detection was employed for determination of pesticides after microwave-assisted-extraction and specific clean-up of deployed samplers. The proposed methodology reached method detection levels from 2 to 10ng pesticide per sampler. Sampling rate (Rs) was determined for every pesticide from an uptake isotherm study performed at three different concentration levels (50, 125, and 250ngL-1). The obtained RS values ranged from 0.06 to 0.76L d-1. The obtained limits of detection for a 24-h passive sampling were from 4 to 50ngL-1. The effect of water parameters, such as temperature, pH, and ionic strength, were evaluated for their effect on pesticides retention using VERAMs. Pesticide RS values were independent of the water composition and increased on increasing temperature. Finally, the VERAM uptake was compared with that obtained using classic semipermeable membrane devices (SPMDs). This study is the first precedent for the use of VERAMs as passive samplers for the adsorption and concentration of pesticides in water and it confirms the satisfactory analytical figures of merit of VERAM as passive sampler of water. Graphical Abstract Scheme of water sampling of pesticides using versatile, easy, and rapid atmospheric monitor (VERAM) passive samplers.

Temperature dependence on the pesticide sampling rate of polar organic chemical integrative samplers (POCIS).

Laboratory experiments were performed to determine the sampling rates of pesticides for the polar organic chemical integrative samplers (POCIS) used in Japan. The concentrations of pesticides in aquatic environments were estimated from the accumulated amounts of pesticide on POCIS, and the effect of water temperature on the pesticide sampling rates was evaluated. The sampling rates of 48 pesticides at 18, 24, and 30°C were obtained, and this study confirmed that increasing trend of sampling rates was resulted with increasing water temperature for many pesticides.

Combination of sorption properties of polydimethylsiloxane and solid-phase extraction sorbents in a single composite material for the passive sampling of polar and apolar pesticides in water.

Passive sampling techniques have been developed as an alternative method for in situ integrative monitoring of trace levels of neutral pesticides in environmental waters. The objective of this work was to develop a new receiving phase for pesticides with a wide range of polarities in a single step. We describe the development of three new composite silicone rubbers, combining polydimethylsiloxane mechanical and sorption properties with solid-phase extraction sorbents, prepared as a receiving phase for passive sampling. A composite silicone rubber composed of polydimethylsiloxane/poly(divinylbenzene-co-N-vinylpyrrolidone) was selected by batch experiments for its high sorption properties for pesticides with octanol-water partition coefficients ranging from 2.3 to 5.5. We named this composite material "Polar/Apolar Composite Silicone Rubber". A structural study by scanning electron microscopy confirmed the homogeneous dispersion of the sorbent particles and the encapsulation of particles within the polydimethylsiloxane matrix. We also demonstrate that this composite material is resistant to common solvents used for the back-extraction of analytes and has a maximal resistance temperature of 350°C. Therefore, the characteristics of the "Polar/Apolar Composite Silicone Rubber" meet most of the criteria for use as a receiving phase for the passive sampling of pesticides.

Pesticides Contaminated in Rice Paddy Soil Affecting on Cultivated Microorganism Community

It has been known for the diversified microbes living in the soil are basic indicators of changes in the ecosystem especially in paddy soil. The effects of continuous application of pesticides in rice field are widely discussed but still disregarded due to unclear and underestimated by the users and the chemicals also need time to accumulate and slowly affect the environment and health. The objective of this research was to understand the effects of pesticides on microorganism community in rice field. Both the numbers and the types of useful soil microorganisms including nitrogen fixing and common habituated microorganisms were compared in between using and not using chemical pesticides samples. The results showed that productivity of cultured microorganisms in the paddy applied with pesticides has dropped only slightly (approximately 9% reduction), however, more spore-forming Gram positive bacteria were detected. Additionally, increases in common microorganisms in the soil at a depth below than 20-50 cm were observed that could possibly be because of less pesticide availability there comparing to the surface of paddy soil. Although the changes in numbers and types of culturable microbes in the paddy soil contaminated with chemical pesticides were less than the actual diversity of species and cultivars, this study could help primarily indicate the adverse effects of the use of chemical pesticides. They thus interfered the ecological balance of the number and type of microorganisms especially at the site doing pesticide application.

Silicone rubber selection for passive sampling of pesticides in water

Silicone rubber can extract organic compounds with a broad range of polarities (logKow>2–3) from aqueous samples. Such compounds include substances of major concern in the protection of aquatic ecosystems and human health, e.g. pesticides. Silicone rubbers (SRs) with various characteristics have been successfully used in sorptive methods for water sample extraction in the laboratory (SPME, SBSE), and for passive sampling in aquatic environments. However, only few studies have evaluated variability in organic compound sorption due to the origin of SRs, particularly for pesticides. The aim of this study was to select an SR for the extraction of pesticides from water samples by passive sampling. To this end we measured the impact of seven SR formulations on sorption capacity, defined by the partition coefficient (Ksw). Kinetic experiments and sorption isotherms were performed to determine extraction recovery as a selection criterion for SRs, and pesticide partition coefficients. Very large differences in affinity for pesticides were found between two kinds of SRs: “Polymerized SR kits” and “Manufactured SRs”. One SR was chosen among the “Manufactured SRs”, and the Ksw values of 21 pesticides were determined, filling a gap in the literature (1.50<logKow<5.51). In light of sorption properties, literature data and additional economic and technical factors, we suggest using SR from Goodfellow in future work to reduce the variability of Ksw literature values.

Ultrasensitive Detection of Residual Pesticides Using THz Near-Field Enhancement

We present a novel type of highly sensitive and selective detection method for residual pesticide molecules including, e.g., methomyl using nanoscale metamaterials based terahertz (THz) time-domain spectroscopy (TDS) system. Nanoscale slot-antenna-based metamaterials were designed for the strong THz resonance at a certain frequency, where the specific molecule has intramolecular or intermolecular collective vibrational mode. Enhanced THz near-field via a nano-antenna metamaterial strongly increases absorption cross section, and this leads to the detection sensitivity up to parts-per-billion level even in a solution state of pesticide sample. Measured transmittance and reflectance spectrum results show excellent performances in both sensitivity and selectivity. We also imaged reflected THz signals though our THz nano-metamaterials in a nondestructive manner to simply detect the contained residual pesticide at the surface of an apple as it is, without any treatment. This observation can offer the possibility for further various applications as prompt and accurate molecule sensing tools in real time.

Rapid identification of pesticides in human oral fluid for emergency management by thermal desorption electrospray ionization/mass spectrometry.

Self-poisoning with pesticides accounts for approximately one-third of all suicides worldwide. To expedite rescue in the emergency department, it is essential to develop a point-of-care analytical method for rapid identification of ingested pesticides. In this study, five of the most common pesticides ingested by self-poisoning patients in Taiwan were analyzed from oral fluid samples. Pesticide-oral fluid mixtures were applied on a cotton swab and then transferred into methanol. A metallic probe was used to sample the methanol solution for subsequent thermal desorption-electrospray ionization mass spectrometry analysis. Altogether, pesticide sampling, transfer, desorption, ionization, and detection took less than 1 min. The reproducibility of this method (n = 6) was shown in the observed low-relative standard deviation (<7%) in the detection of pesticide in oral fluid. The detection limits of the pesticides in oral fluid obtained from four human subjects by thermal desorption-electrospray ionization mass spectrometry were between 1-10 ppb with relative standard deviation 10.7%. Moreover, in this study, linear responses of five pesticides in oral fluid with concentrations between 1 ppb-1 ppm (R2 between 0.9938 and 0.9988) were observed. As the whole analytical process is extremely short, this technique allows for early non-invasive point-of-care identification of pesticides in the oral fluid of self-poisoning patients in the emergency room, providing important toxicological information for decision-making during critical resuscitation.

Employing Solid Phase Microextraction as Extraction Tool for Pesticide Residues in Traditional Medicinal Plants.

HS-SPME was optimised using blank plant sample for analysis of organochlorine pesticides (OCPs) of varying polarities in selected medicinal plants obtained from northern part of Botswana, where OCPs such as DDT and endosulfan have been historically applied to control disease carrying vectors (mosquitos and tsetse fly). The optimised SPME parameters were used to isolate analytes from root samples of five medicinal plants obtained from Maun and Kasane, Botswana. The final analytes determination was done with a gas chromatograph equipped with GC-ECD and analyte was confirmed using electron ionisation mass spectrometer (GC-MS). Dieldrin was the only pesticide detected and confirmed with MS in the Terminalia sericea sample obtained from Kasane. The method was validated and the analyte recoveries ranged from 69.58 ± 7.20 to 113 ± 15.44%, with RSDs ranging from 1.19 to 17.97%. The method indicated good linearity (R 2 > 0.9900) in the range of 2 to 100 ng g−1. The method also proved to be sensitive with low limits of detection (LODs) ranging from 0.48 ± 0.16 to 1.50 ± 0.50 ng g−1. It can be concluded that SPME was successfully utilized as a sampling and extraction tool for pesticides of diverse polarities in root samples of medicinal plants.

Measuring IPM Impacts in California and Arizona.

Integrated pest management (IPM) is a method of reducing economic, human health, and environmental risks from pests and pest management strategies. There are questions about the long-term success of IPM programs in relation to continued use of pesticides in agriculture. Total pounds of pesticides applied is a mis-measure of the impact of IPM in agriculture. A more complete measurement of the long-term impact of IPM includes consideration of changes in agricultural production practices and productivity, toxicity of the pesticides used, risks from human exposure to pesticides, and environmental sampling for pesticides in air and water resources. In recent decades, agricultural IPM programs have evolved to address invasive pests, shifts in endemic pest pressures, reductions in pest damage tolerance in markets, and increases in crop yields. Additionally, pesticide use data from Arizona and California revealed reduced use of pesticides in some toxicity categories but increased use of pesticides in a couple of categories. Data from federal and California programs that monitored pesticide residue on food have documented low pesticide risk to consumers. Environmental monitoring programs documented decreased pesticide levels in surface water resources in agricultural watersheds in the western United States and low levels of pesticides in air resources in agricultural areas in California. The focus of IPM assessment should be on reducing economic, human health, and environmental risks, not on pounds of pesticides applied. More broadly, IPM programs have evolved to address changes in pests and agricultural production systems while continuing to reduce human health and environmental risk from pesticides.

The Pig-A assay – Its potential applications in regulatory mutagenicity testing

Herein we present a novel sandwich structure test strip for organophosphorus (OP) assessment, which is applicable and portable for field application. The middle layer of the strip is made of rhodamine B-covered gold nanoparticles (RB–Au NPs) entrapped in agarose and its coated layer is made of hydrogel (Poly ethylene glycol diacrylate) used as protectors for the center agarose layer. The OP assessment is based on the measurement of the concentration changing of thiocholine (generated from acetylthiocholine catalyzed by acetylcholinesterase in tested solution) when OP exist. The strip was further validated by various pesticide samples. Its detection limit was demonstrated to meet the maximum residue limits reported in the European Union pesticides database. Our strip also showed its good sensitivity and high reliability on testing river water samples, which suggested its great potential in environmental analysis.

Application of chemometric analysis based on physicochemical and chromatographic data for the differentiation origin of plant protection products containing chlorpyrifos

The aim of this study was to investigate the similarities and dissimilarities between the pesticide samples in form of emulsifiable concentrates (EC) formulation containing chlorpyrifos as active ingredient coming from different sources (i.e., shops and wholesales) and also belonging to various series. The results obtained by the Headspace Gas Chromatography–Mass Spectrometry method and also some selected physicochemical properties of examined pesticides including pH, density, stability, active ingredient and water content in pesticides tested were compared using two chemometric methods. Applicability of simple cluster analysis and also principal component analysis of obtained data in differentiation of examined plant protection products coming from different sources was confirmed. It would be advantageous in the routine control of originality and also in the detection of counterfeit pesticides, respectively, among commercially available pesticides containing chlorpyrifos as an active ingredient.

Genotoxicity assessment of pesticides on terrestrial snail embryos by analysis of random amplified polymorphic DNA profiles

The study explores the relevance of coupling Random Amplified Polymorphic DNA (RAPD) and a High-Resolution capillary electrophoresis System (HRS) method for assessing the genotoxic potential of the wide variety commercial formulations of pesticides. Using this technique, the genotoxic potential of a glyphosate-based herbicide (Roundup Flash® (RU)) and two fungicide formulations based on tebuconazole and copper (Corail® and Bordeaux mixture (BM), respectively) was evaluated on terrestrial snail embryos. Clutches of Cantareus aspersus were exposed during their entire embryonic development to a range of concentration around the EC50 values (based on hatching success) for each compound tested. Three primers were used for the RAPD amplifications of pesticides samples. RAPD–HRS revealed concentration-dependent modifications in profiles generated with the three primers in RU®-exposed embryos from 30mg/L glyphosate. For Corail®-exposed embryos, only two of the three primers were able to show alterations in profiles from 0.05mg/L tebuconazole. For BM-exposed embryos, no signs of genotoxicity were observed. All changes observed in amplification profiles have been detected at concentrations lower than the recommended doses for vineyard field applications. Our study demonstrates the efficiency of coupling RAPD and HRS to efficiently screen the effect of pesticide formulations on DNA.

Feasibility and informative value of environmental sample collection in the National Children's Vanguard Study

BackgroundBirth cohort studies provide the opportunity to advance understanding of the impact of environmental factors on childhood health and development through prospective collection of environmental samples. MethodsWe evaluated the feasibility and informative value of the environmental sample collection methodology in the initial pilot phase of the National Children's Study, a planned U.S. environmental birth cohort study. Environmental samples were collected from January 2009–September 2010 at up to three home visits: pre-pregnancy (n=306), pregnancy (n=807), and 6-months postnatal (n=117). Collections included air for particulate matter ≤2.5µm (PM2.5), nitrogen dioxide, ozone, volatile organic compounds (VOCs), and carbonyls; vacuum dust for allergens/endotoxin; water for VOCs, trihalomethanes (THMs), and haloacetic acids (HAAs); and wipe samples for pesticides, semi-volatile organics, and metals. We characterized feasibility using sample collection rates and times and informative value using analyte detection frequencies (DF). ResultsAmong the 1230 home visits, environmental sample collection rates were high across all sample types (mean=89%); all samples except the air PM2.5 samples had collection times <30min. Informative value was low for water VOCs (median DF=0%) and pesticide floor wipes (median DF=5%). Informative value was moderate for air samples (median DF=35%) and high for water THMs and HAAs (median DF=91% and 75%, respectively). ConclusionsThough collection of environmental samples was feasible, some samples (e.g., wipe pesticides and water VOCs) yielded limited information. These results can be used in conjunction with other study design considerations, such as target population size and hypotheses of interest, to inform the method selection of future environmental health birth cohort studies.

HPLC Uv‐Vis Analysis of Multiple Pesticides Extracted from Biological Tissues: Effects of Acetonitrile/Hexane on Detection.

Exposure to chlorinated pesticides continues to be of great public health concern. They are extremely persistent; accumulate in sediments, plants, and animals with high bioaccumulation potentials in human contributing to chronic health conditions. Effective and comprehensive methods to determine presence of multiple pesticides (MP) in biological samples are desirable. We have determined the concentration of MP in different organs from rats exposed to MP (endosulfan 1/2, Endrin, Dieldrin, 4,4-DDT, and Aldrin: 1/100 (LD50) in a mixture orally) for 2 weeks in corn oil. Rats' livers, hearts, kidneys, and brains were soaked and homogenized in acetonitrile or hexane to determine better extraction. Samples were homogenized, centrifuged, dried, and reconstituted in 1 mL hexane or acetonitrile. Standards of individuals and mixtures were run to obtain standard calibrations and retention times using HPLC Uv-Vis. The standards eluted at 12.90, 14.90, 15.77, 15.90, 20.06, and 29.20 minutes for (endosulfan 1 and 2, Endrin, Dieldrin, 4, 4-DDT, and Aldrin, respectively. Acetonitrile extracted samples showed significantly higher yield of chlorinated pesticides compared to hexane with a ratio (Acetonitrile: Hexane) of 13:1 (brain); 18:1 (kidney); 366:1 (heart) and 1,186:1 (liver) for the detection of endosulfan 1. While endosulfan 2 showed 1:1 (brain); 39:1 (kidney); 161:1 (liver). Except dieldrin, all other pesticides were detected with lower ratios. Thus, our results indicate that the media used to extract chlorinated pesticides samples could have significant effects on the yields and hence quantification probably leading to under estimation of chlorinated pesticides burden in biological systems/samples.

온라인 판매 농산물 잔류농약 실태 및 안전성 평가

본 연구는 2014년도 온라인으로 판매되고 있는 농산물의 잔류농약 실태와 안전성 평가를 시행하였다. 총 124건의 농산물(엽채류 98건, 엽경채류 26건)을 2014년도 3월부터 8월까지 6차례 20곳의 온라인 쇼핑몰을 통해 무작위로 수거 및 전처리 후 GC-ECD/NPD와 LC-MS/MS를 사용하여 208종의 농약을 분석하였다. 실험 결과 깻잎, 깻순, 부추, 쑥, 열무, 대파, 취나물 7종 11건(8.9%)의 농산물에서 11종의 농약 19건이 검출되었다. 농산물 중 2건(깻순, 쑥)에서는 잔류허용기준치 이상의 농약이 검출되었다. 검출된 농약의 EDI(Estimated daily intake)와 ADI(Acceptable daily intake)를 비교하여 안전성 평가를 시행한 결과 %ADI가 100%를 넘는 대상은 없었으나 클로로타로닐이 잔류허용기준치 이상 검출된 깻순에서는 95.7%의 결과를 보이는 등 안전성 관리가 필요한 실정이었다. 본 연구결과는 앞으로 국가 농산물 잔류농약 안전성 검사 정책 결정의 기초자료로 활용될 수 있을 것으로 생각한다. This study was carried out to monitor the current status of pesticide residues in selling agricultural products via online and assessed their safety in 2014. A total of 124 samples were purchased six times from March to August 2014 twenty online shopping malls randomly. These samples were analysed 208 pesticides by multiresidue method using a GC-ECD/NPD and a LC-MS/MS and confirmed by a GC-MSD. As a result of analysis, residual pesticides samples were 11 (8.9%) such as leek, young radish, welsh onion etc, of which 2 samples (1.6%) such as sesame bud (Chlorothalonil), artemisia (Chlorpyrifos) were violated Korea Maximum Residue limits (MRLs). 11 kinds of pesticides (19 times) were detected in 11 samples. Risk assessment evaluated human health exposure with the ratio of EDI (Estimated daily intake) to ADI (Acceptable daily intake) of pesticides detected. %ADI (the ratios of EDI to ADI) were 0.04~95.70% and some samples represented a fairly dangerous levels. In particular, Chlorothalonil in the sesame bud was shown as a significant risk close to 100% of %ADI. Accordingly, it is recommended to strengthen a safety check on agricultural products in online sales.

Phosphate fertilizer is a main source of arsenic in areas affected with chronic kidney disease of unknown etiology in Sri Lanka.

Chronic Kidney Disease of unknown etiology (CKDu) has escalated into an epidemic in North Central Province (NCP) and adjacent farming areas in the dry zone of Sri Lanka. Studies have shown that this special type of CKD is a toxic nephropathy and arsenic may play a causative role along with a number of other heavy metals. We investigated the hypothesis that chemical fertilizers and pesticide could be a source of arsenic. 226 samples of Fertilizers and 273 samples of pesticides were collected and analyzed using atomic absorption spectrometry and inductively coupled plasma mass spectrometry for arsenic and other heavy metals in two university laboratories. Almost all the agrochemicals available to the farmers in the study area are contaminated with arsenic. The highest amount was in triple super phosphate (TSP) with a mean value of 31 mg/kg. Also TSP is a rich source of other nephrotoxic metals including Cr, Co, Ni, Pb and V. Annually more than 0.1 million tons of TSP is imported to Sri Lanka containing approximately 2100 kg of arsenic. The next highest concentration was seen in the rock phosphate obtained from an open pit mine in NCP (8.56 mg/kg). Organic fertilizer contained very low amounts of arsenic. Arsenic contamination in pesticides varied from 0.18 mg/kg to 2.53 mg/kg although arsenic containing pesticides are banned in Sri Lanka. Glyphosate the most widely used pesticide in Sri Lanka contains average of 1.9 mg/kg arsenic. Findings suggest that agrochemicals especially phosphate fertilizers are a major source of inorganic arsenic in CKDu endemic areas. Organic fertilizer available in Sri Lanka is comparatively very low in arsenic and hence the farmers in CKDu endemic areas in Sri Lanka should be encouraged to minimize the use of imported chemical fertilizer and use organic fertilizers instead.

A novel test strip for organophosphorus detection

Herein we present a novel sandwich structure test strip for organophosphorus (OP) assessment, which is applicable and portable for field application. The middle layer of the strip is made of rhodamine B-covered gold nanoparticles (RB–Au NPs) entrapped in agarose and its coated layer is made of hydrogel (Poly ethylene glycol diacrylate) used as protectors for the center agarose layer. The OP assessment is based on the measurement of the concentration changing of thiocholine (generated from acetylthiocholine catalyzed by acetylcholinesterase in tested solution) when OP exist. The strip was further validated by various pesticide samples. Its detection limit was demonstrated to meet the maximum residue limits reported in the European Union pesticides database. Our strip also showed its good sensitivity and high reliability on testing river water samples, which suggested its great potential in environmental analysis.

Sampling and analysis of pesticides in the gas phase of air: method validation using a volatilization chamber

This study aimed to develop and validate an analytical method for the determination of pesticides in the gas phase of air employing a simple and cheap apparatus to simulate atmospheric contamination.

Organophosphate Hydrolase in Conductometric Biosensor for the Detection of Organophosphate Pesticides.

The research has developed an enzyme biosensor for the detection organophosphate pesticide residues. The biosensor consists of a pair of screen-printed carbon electrode (SPCEs). One of electrodes contains immobilized organophosphate hydrolase (OPH) on a chitosan membrane by cross-linking it with glutaraldehyde. The area of the electrodes was optimized to 3, 5, and 7 mm2. The OPH was isolated from Pseudomonas putida, and was purified by the ammonium sulfate precipitation method, with 6444 ppm (A) and 7865 ppm (B). The organophosphate pesticide samples were 0–100 ppb in tris-acetate buffer 0.05 M, pH 8.5. The results showed that the best performance of the biosensor was achieved by the enzyme A with an electrode area of 5 mm2. The sensitivity of the biosensor was between 3 and 32 µS/ppb, and the detection limit for the organophosphate pesticides was 40 ppb (diazinon), 30 ppb (malathion), 20 ppb (chlorpyrifos), and 40 ppm (profenofos).