Trace Pesticides Research Articles

Au-modified metal-organic framework photonic heterostructure as a SERS sensor for enrichment and detection of trace organic dyes and pesticides

Surface enhanced Raman scattering (SERS) sensors with excellent sensitivity, stability and repeatability are essential for the ultrasensitive analysis of trace targets. In this study, a SERS sensor was developed using a photonic heterostructure composed of Au nanoparticles (AuNPs) & Zeolitic Imidazolate Framework-8 photonic crystals (ZIF-8 PCs). The sensor aims to enrich and detect organic dyes and pesticides, with enhanced detection capabilities achieved through adjustments in AuNPs content and the band-edge effects of ZIF-8 PCs. The sensor exhibited excellent performances in detecting 4-mercaptobenzoic acid. The detection limit was 1 × 10–12 mol·L−1, with a relative standard deviation of 5.0 % and the enhancement factor of 1.439 × 1011. Furthermore, the self-enrichment function of the sensor was verified through molecular dynamics simulations. This validation enabled the SERS sensor to be effectively utilized for the analysis of Rhodamine 6 G (R6G), methylene blue (MB), Thiabendazole (TBZ) and Parathion-methyl (PTM) without complex pretreatment. The detection limits achieved were 1 × 10–12 for R6G and MB, and 1 × 10–11 mol·L−1 for TBZ and PTM, respectively. This study presented an effective strategy for constructing high-performance SERS sensors, elucidated the mechanism of analyte enrichment and achieved the detection of samples in natural lake water, which offers a new option for on-site monitoring of contaminants with a portable Raman spectroscopy.

Quality Of Drinking Water In An Area With High Gold Panning Activity In Côte d'Ivoire (Daloa, Centre-West)

Background: Gold panning has experienced remarkable growth in recent decades in Côte d’Ivoire. This activity contributes substantially to local economies. However, the use of toxic chemicals has an impact on human health and the environment, particularly water resources. The aim of this study was to evaluate the level of contamination of drinking water by metallic trace elements, cyanide and pesticides in an area with high gold panning activity in Côte d'Ivoire. Materials and Methods: Five (5) surface water samples and 5 well water samples were collected in the area of the gold panning sites and then analyzed. The metallic trace elements were measured by atomic absorption spectrometry. Total cyanides were measured according to the NF EN ISO 14403-1 standard and the pesticides were analyzed using a UV-visible HPLC chain. Results:The average concentrations of the metallic trace elements found were 0.125; 0.002; 0.046; 0.036 and 0.009 µg/L respectively for arsenic, Cadmium, Iron, Lead and mercury in surface waters. In the well water, the concentrations of arsenic, cadmium, iron, lead and mercury were respectively 0.025; 0.001; 0.009; 0.007 and 0.002 µg/L. The average concentration of arsenic in all surface water samples and three well water samples was higher than the standard set by WHO (0.01 mg/Kg) for drinking water. Lead and mercury levels in surface water were also higher than recommended standards for drinking water. Cyanide has been found in surface and well waters at relatively low concentrations. Twenty-five pesticides belonging to the chemical families of organochlorines, organophosphates, carbamates and other compounds derived from urea and atrazine were found in the water samples analyzed. Farmer’s well water was qualitatively the most contaminated with the simultaneous presence of several pesticides. The sum of the measured pesticide concentrations for each sample complied with the recommendations for drinking water, set at 0.50 µg/L. Conclusion: Drinking water in this locality is contaminated by metallic trace elements, cyanide and pesticides. The quality of drinking water in this locality must be subject to permanent monitoring in order to protect the health of the population.

Assessment of the Dissipation Behaviors, Residues, and Dietary Risk of Oxine-Copper in Cucumber and Watermelon by UPLC-MS/MS.

During production, agricultural products are often susceptible to potential harm caused by residual traces of pesticides. Oxine-copper is a broad spectrum and efficient protective fungicide widely used in the production of fruits and vegetables. The present study was carried out to profile the dissipation behaviors and residues of oxine-copper on cucumber and watermelon using QuEChERS pretreatment and UPLC-MS/MS. Its storage stability and dietary risk assessment were also estimated. The method validation displayed good linearity (R 2 ≥ 0.9980), sensitivity (limits of quantification ≤0.01 mg/kg), and recoveries (75.5-95.8%) with relative standard deviations of 2.27-8.26%. According to first-order kinetics, the half-lives of oxine-copper in cucumber and watermelon were 1.77-2.11 and 3.57-4.68 d, respectively. The terminal residues of oxine-copper in cucumber and watermelon samples were within <0.01-0.264 and <0.01-0.0641 mg/kg, respectively. Based on dietary risk assessment, the estimated long-term dietary risk probability value of oxine-copper in cucumber and watermelon is 64.11%, indicating that long-term consumption of cucumber and watermelon contaminated with oxine-copper would not pose dietary risks to the general population. The results provide scientific guidance for the rational utilization of oxine-copper in field ecosystems of cucumber and watermelon.

Confined within a sugarcane monoculture: A participatory assessment of water pollution and potential health risks in the community of El Tiple, Colombia

Communities neighboring monoculture plantations are vulnerable to different forms of pollution associated with agro-industrial operations. Herein, we examine the case of El Tiple, a rural Afro descendant community embedded within one of the largest sugarcane plantations in the Americas. We implemented a participatory approach to assess water pollution, exposure via water ingestion, and non-carcinogenic health risks associated with the use of local water sources available to the community. We conducted household surveys to unveil demographic characteristics and family dynamics linked to water consumption. Additionally, we measured water quality parameters and assessed the concentration glyphosate, its major metabolite (aminomethylphosphonic acid) and metals and metalloids. Drinking water El Tiple households is sourced from three primary sources: the local aqueduct system, water delivery trucks, and private deep wells. Tests on water samples from both the local aqueduct and delivery trucks showed no traces of pesticides, metals, or metalloids surpassing regulatory limits set by Colombian or EPA standards. However, we found concentration of contaminants of primary concern, including mercury (up to 0.0052 ppm) and lead (up to 0.0375 ppm) that exceed the permissible regulatory thresholds in water from groundwater wells. Residents of the peripheric subdivisions of El Tiple are four times more reliant on well water extraction than residents of the central area of the town due to lack of access to public drinking water and sanitation infrastructure. Finally, adult women and school-age children have a higher health risk associated with exposure to local pollutants than adult men due to their constant presence in the town. We conclude that expanding the coverage of clean water and sanitation infrastructure to include all households of the community would be the most recommended measure to minimize exposure and risk via ingestion of water pollutants.

Electrochemical detection of carbendazim using molecularly imprinted poly(3,4-ethylenedioxythiophene) on Co,N co-doped hollow carbon nanocage@CNTs-modified electrode

Precisely detecting trace pesticides and their residues in food products is crucial for ensuring food safety. Herein, a high-performance electrochemical sensing platform was developed for the detection of carbendazim (CBZ) using Co,N co-doped hollow carbon nanocage@carbon nanotubes (Co,N-HC@CNTs) obtained from core–shell ZIF-8@ZIF-67 combined with a poly(3,4-ethylenedioxythiophene) (PEDOT) molecularly imprinted polymer (MIP). The Co,N-HC@CNTs exhibited excellent electrocatalytic performance, benefitting from the synergistic effect of CNTs that provide a large specific surface area and excellent electrical conductivity, Co,N co-doped carbon nanocages that offer high electrocatalytic activity and hollow nanocage structures that ensure rapid diffusion kinetics. The conductive PEDOT-MIP provided specific binding sites for CBZ detection and significantly amplified the detection signal. The sensor showed superior selectivity for CBZ with an extremely low detection limit of 1.67 pmol L−1. Moreover, the method was successfully applied to detect CBZ in tomato, orange and apple samples, achieving satisfactory recovery and accuracy, thus demonstrating its practical feasibility.

A novel sustainable immunoassay for sensitive detection of atrazine based on the anti-idiotypic nanobody and recombinant full-length antibody

Immunoassays have been widely used to determine small-molecule compounds in food and the environment, meeting the challenge of obtaining false positive or negative results because of the variance in the batches of antibodies and antigens. To resolve this problem, atrazine (ATR) was used as a target, and anti-idiotypic nanobodies for ATR (AI-Nbs) and a recombinant full-length antibody against ATR (ATR-rAb) were prepared for the development of a sustainable enzyme-linked immunosorbent assay (ELISA). AI-Nb-7, AI-Nb-58, and AI-Nb-66 were selected from an immune phage display library. ATR-rAb was produced in mammalian HEK293 (F) cells. Among the four detection methods explored, the assay using AI-Nb-66 as a coating antigen and ATR-rAb as a detection reagent yielded a half maximal inhibitory concentration (IC50) of 1.66 ng mL−1 for ATR and a linear range of 0.35 − 8.73 ng mL−1. The cross-reactivity of the assay to ametryn was 64.24 %, whereas that to terbutylazine was 38.20 %. Surface plasmon resonance (SPR) analysis illustrated that these cross-reactive triazine compounds can bind to ATR-rAb to varying degrees at high concentrations; however, the binding/dissociation kinetic curves and the response values at the same concentration are different, which results in differences in cross-reactivity. Homology modeling and molecular docking revealed that the triazine ring is vital in recognizing triazine compounds. The proposed immunoassay exhibited acceptable recoveries of 84.40 − 105.36 % for detecting fruit, vegetables, and black tea. In conclusion, this study highlights a new strategy for developing sustainable immunoassays for detecting trace pesticide contaminants.

Assessing the water quality in a World Heritage Site using biomarkers in top fish predators

The use of biomarkers in fish for biomonitoring is a valuable approach to reveal effects of human impacts on biota health. Top predator fish are effective models for monitoring human activities' impacts on aquatic ecosystems. The Guaraguaçu River is the largest river-system on coastal region of South Brazil and a World Heritage site. The river receives contaminants from disorderly urban growth, including discharges of domestic sewage and small fishery boats, particularly during the tourist season. Our study aimed to assess impact of anthropogenic activities on water quality in the Guaraguaçu River by analyzing environmental contamination biomarkers in the top fish predator Hoplias malabaricus. Fish were collected using a fyke net trap across sectors representing a gradient of anthropic impact: sector 1 - pristine; sector 2 – impacted; and sector 3 - less impacted. Water samples were collected to analyze the presence of trace elements and pesticide. Biomarkers of the antioxidant system, histopathology, genotoxicity, neurotoxicity, and concentration of trace elements were analyzed in fish tissues. In water samples Al, Fe and Mn were detected, but no pesticides were found. In fish muscle, zinc and iron were detected. Brain acetylcholinesterase activity decreased in impacted sectors, indicating neurotoxic effects. The antioxidant system increased activity in gills and liver, and damage from lipoperoxidation was observed, particularly in sector 2 when compared to sector 1, suggesting oxidative stress. Histopathological biomarkers revealed lesions in the liver and gills of fish in impacted sectors. Micronuclei, a genotoxicity biomarker, were observed in organisms from all sectors. Our results demonstrate detrimental effects of poor water quality on biota health, even when contaminants are not detected in water.

Traces of Pesticides in Sources of Drinking Water in a Hilly Region of Uttarakhand

Traces of Pesticides in Sources of Drinking Water in a Hilly Region of Uttarakhand

Triple-helix as a target converter for trace pesticide detection based on CRISPR/Cas12a-based ECL biosensor

Developing a convenient and sensitive biosensor for trace pesticide detection is vital to guarantee food safety. Herein, we designed a triple-helix as a universal target converter coupling with CRISPR/Cas12a-based electrochemiluminescence (ECL) biosensor for the detection of trace pesticide pesticides. The aptamer with extending auxiliary sequences at both ends was designed and interacted with the primer to form the triple-helix DNA as the target converter, which exposed the aptamer sequence at the loop of the triple-helix. The binding event between the target and aptamer sequence would make the triple-helix deconstruct to expose the primer for the rolling circle amplification (RCA) initiation. With the template customization, the RCA product was encoded with a DNAzyme/substrate unit, which was cleaved into generous short DNA activators with the assistance of Zn2+ for efficient CRISPR/Cas12a activation. Finally, the activated CRISPR/Cas12a cleaved the quenching probes assembled on the electrode for signal output. Take acetamiprid as a model, the fabricated ECL biosensor based on zeolitic imidazolate framework-8 encapsulated perylene (ZIF-8@Pe) as ECL luminophore exhibited excellent selectivity and sensitivity with the linear of 1 pM ∼ 100 μM and the limit of detection (LOD) of 394 fM. Furthermore, the universality of the target converter is realized by replacing the aptamer sequence of the triple-helix and the developed biosensor is anticipated to be applied in various pesticide molecule detection.

Developing a magnetic SERS nanosensor utilizing aminated Fe-Based MOF for ultrasensitive trace detection of organophosphorus pesticides in apple juice

The unreasonable use of organophosphorus pesticides leads to excessive pesticide residues in food, seriously threatening public health, and the potential of surface-enhanced Raman spectroscopy (SERS) technology, incorporating a metal–organic framework, is substantial for the rapid detection of trace pesticide residues. Here, a novel Fe3O4@NH2-MIL-101(Fe)@Ag (FNMA) SERS nanosensor was developed. Results indicated that the FNMA had a high enhancement factor of 1.53 × 108, a low limit of detection (LOD) of 4.55 × 10−12 M, and a relative standard deviation of 7.73 % for 4-nitrothiophenol, demonstrating its good SERS sensitivity and uniformity, and also possessed good storage stability for one month. In quantifying fenthion and methyl parathion in standard solutions and apple juice in the range of 0.05/0.02–20 mg/L, it showed LODs of 3.02 × 10−3 mg/L and 1.43 × 10−3 mg/L, and 0.0407 and 0.0075 mg/L, respectively, demonstrating potentials in ultrasensitive trace detection of pesticides in food.

Simultaneous determination of sulfonylurea herbicides in tomatoes using the QuEChERS method coupled with HPLC

The simultaneous determination of trace pesticides in complex matrices containing high concentrations of natural pigments remains challenging. In this study, quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation together with high-performance liquid chromatography with ultraviolet detection (HPLC–UV) was applied for the multi-residue analysis of seven sulfonylurea herbicides (SUHs) in tomatoes. SUH residue was extracted using the QuEChERS procedure, followed by solid-phase extraction (SPE) and dispersive SPE (d-SPE). To reduce the amount of carotenoids in tomato extracts, several d-SPE clean-up procedures were compared, and octadecylsilane (C18) provided the best color removal rate (%) of tomato extracts and recoveries (%) for all the tested SUHs. The validation results indicate good linearity (R2 > 0.9970), accuracy, and precision. Recoveries of 70–120% and relative standard deviations < 20% were achieved for all analytes at three spiked concentrations. The limits of detection and quantification for the 7 SUHs were 0.003 mg kg−1 and 0.008–0.009 mg kg−1, respectively. The developed method was subsequently used to quantify multi-residue SUHs during real sample analysis. None of the tested samples had SUH residue levels higher than the maximum residue limits established by the Korean Ministry of Food and Drug Safety. The results suggest that QuEChERS sample preparation employing a combination of C18 is a high-throughput and rapid clean-up procedure for the multi-residue analysis of SUHs in tomatoes.

MIL-53/UiO-66/PAN beads as a novel adsorbent for simultaneous extraction of trace pesticides in wheat, wheat flour and field soil followed by GC-MS analysis

To develop a facile, efficient and sensitive method for simultaneous determination of multiple pesticides in wheat, wheat flour and field soil, a novel MIL-53/UiO-66/PAN bead was successfully prepared and applied as adsorbent in a simplified dispersive solid-phase extraction (d-SPE) followed by GC-MS analysis. Moreover, the MIL-53/UiO-66/PAN bead could be directly separated owing to its scale of millimeter, which overcome the shortcomings of traditional d-SPE. After optimization of key factors by Response Surface Methodology, the proposed method exhibited excellent linearity (R2> 0.99) and detection limits of 0.17-1.21µg/L. Furthermore, recoveries were in range of 77.8-98.3%, with RSDs lower than 9.2%. Finally, the developed method was successfully applied to the determination of pesticides in wheat, wheat flour and soil from wheat field, where Triadimefon was detected in wheat and soil samples at a concentration of 28.7 and 36.9µg/kg, respectively. The results demonstrated that the MIL-53/UiO-66/PAN-based d-SPE-GC-MS method provided a more convenient strategy for efficient extraction and determination of pesticides in wheat, wheat flour and field soil.

Highly sensitive flexible SERS substrates with a sandwich structure for rapid detection of trace pesticide residues

Compared to rigid surface-enhanced Raman scatting (SERS) substrates, flexible SERS substrates offer significant advantages for the detection of pesticide residues on vegetable and fruit surfaces, primarily due to their convenient sampling process and shorter detection times. However, for paper-based SERS substrates, gold nanoparticles (AuNPs) are easy to form ineffective dispersion in the three-dimensional network structure of paper, resulting in unsatisfactory SERS enhancement. To address this challenge and achieve high-performance flexible SERS substrates, a novel sandwich structure is proposed. Specifically, AuNPs are aggregated on expanded graphite (EG) through a chemical enhancement process facilitated by LiCl. EG is found to improve the adsorption capacity of targeted molecules while preventing signal attenuation caused by filter papers. By employing an aggregating agent at specific concentrations, it is possible to significantly increase the amounts of hot spots to provide a more pronounced enhancement effect. Furthermore, the developed flexible SERS substrates are applied to qualitatively and quantitatively detect pesticide residues, including Thiram, Nitrofural and Dinotefuran. The flexible SERS substrates demonstrate high accuracy and robustness, making them easily storable and suitable for practical applications.

Trace metals and pesticides in water-sediment and associated pollution load indicators of Netravathi-Gurupur estuary, India: Implications on coastal pollution

Various environmental indicators were used to evaluate the water and sediment quality of the Netravathi-Gurupur estuary, India, for trace metals and pesticide pollution. The descended order of studied metal concentrations (μg/L) in the water was Fe (592.71) > Mn (98.35) > Zn (54.69) > Cu (6.64) > Cd (3.24) > Pb (2.38) > Cr (0.82) and in sediment (mg/kg) was Fe (11,396.53) > Mn (100.61) > Cr (75.41) > Zn (20.04) > Cu (12.77) > Pb (3.46) > Cd (0.02). However, pesticide residues were not detected in this estuarine environment. The various metal indexes categorised the water as uncontaminated, whereas contamination factor, enrichment factor, geo-accumulation index, degree of contamination and pollution load index indicated low to moderate sediment contamination. Multivariate statistics showed that the dominance of natural sources of trace metals with little anthropogenic impact. Improvement in water/sediment quality during the study period might be due to COVID-19 imposed lockdown.

Standardization of Babbularishta – A Marketed Ayurvedic Formulation as per WHO Guidelines

Ayurveda is the world’s oldest continuous medicinal tradition. Ayurveda’s discovery of the long-lasting single-dose forms of Asava and Arishta is a boon to modern medicine. Diarrhea, colitis, chronic cough, asthma, tuberculosis, and improved digestive function are only a few of the conditions for which the ayurvedic formulation Babbularishta is utilized. Gallic acid is one of the active ingredients in babbularishta, a commercially available ayurvedic medicine. The purpose of this study was to develop a standard for the quality of commercially available Babbularishta by measuring its alcohol content and pH. To meet World Health Organisation (WHO) standards, an high-performance liquid chromatography (HPLC) and ultraviolet (UV) method was devised for quantifying the main component, gallic acid, in babbularishta. Gas chromatography and redox titrimetry were used to confirm the accuracy of the formulation determined during the development process. The formulation was further tested for pharmacological activity, elemental makeup, pesticide traces, and heavy metal concentration.

TRACES OF GLYPHOSATE IN CORN (Zea mays L.) AND AVOCADO (Persea americana Mill.) WEEDS SUPPORTED BY VANT AND RAMAN SPECTROSCOPY

Since the 1990s, radiometric and biophotonic sensor applications have provided reliable alternatives and rapid non-invasive diagnostics for the detection and delimitation of pests and diseases, as well as pesticide traces. Active sensors have been shown to be more accurate in detecting the heterogeneity of environmental factors based on thermal and infrared characteristics, chlorophyll fluorescence, and plant reflectance. Unmanned Aerial Vehicles (UAVs) equipped with infrared cameras locate and delimit weed abundance and diversity using Normalized Difference Vegetation Index (NDVI) algorithms, which highlight heterogeneous chlorophyll activity and herbicide-limited photosynthesis in crops. The resulting map serves as the foundation for collecting plant samples. In this study, the technology of these sensors was applied to determine glyphosate traces using Raman spectroscopy, which allowed a quick, low-cost, simple, and practical diagnosis with immediate results. These are essential characteristics for surveillance and monitoring activities, as well as the basis for a geo-referenced inventory of pesticides in production units. Of the 44 weed samples collected, eight were positive for glyphosate traces: two in corn and six in avocado. Weeds are identified as positive to glyphosate traces in Raman spectroscopy in the carotenoid and phenylpropanoid reduction ranges (1186 and 1213 cm-1) as a result of a decrease in the immune response. The vibrations presented by the amines in glyphosate and the C-OH of the carboxyl group are detected in the range of 1565 and 1567 cm-1.

Ultra-Trace Electrochemical Determination of Glyphosate Using Bimetallic Metal–Organic Frameworks (MOFs) with Differential Pulse Voltammetry

Hierarchically bimetallic Zr-Cu metal–organic framework combined with 1,3,5-benzenetricarboxylic acid (Zr-CuBTC MOFs) was synthesized using hydrothermal reaction and used as modifier for investigation of non-electroactive glyphosate. These MOFs were dropcasted on a glassy carbon electrode (GCE) and non-electroactive glyphosate were tested by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Glyphosate in water was recognized by the difference of currents in spiked and non-spiked glyphosate samples. At the same time, CuBTC and Fe-CuBTC were investigated for the best material for sensor development. The results showed the bimetallic Zr-CuBTC MOF is the most promising for the determination of glyphosate. Morphological and structural studies showed the coordination of Cu2+ with the presence of Zr4+ ions with BTC ligands provided a highly porous framework with active surface area up to 1337 m2 g−1. The pore diameter and pore volume increased to 1.75 nm and 0.687 cm3 g−1, respectively. Under optimal conditions, Zr-CuBTC modified on GCE (Zr-CuBTC/GCE) sensor is able to indirectly detect glyphosate in a water environment at a detection limit as low as 9 × 10−13 M. The developed sensor was employed to determine glyphosate in the surface water samples collected from the Red River, North Vietnam. The results showed good recoveries (94.6–107.1%) which were in agreement with liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) measurements. These results demonstrate the possibility of using this MOF material in sensor applications to determine trace pesticides in the contaminated water.

Food safety and quality training: The use of a lateral flow immunochromatographic strip test for rapid detection of pesticide residue on leafy vegetables

Ensuring the safety and quality of leafy vegetables, especially by controlling any traces of pesticides, is crucial for maintaining human health. This international community service program was designed to expand the vocational knowledge and skills of the people of Timor-Leste in using lateral flow immunochromatographic strip tests for quickly detecting pesticide residue on leafy vegetables. The program was organized by UAD in partnership with PCIM Timor-Leste and the An-Nur Islamic Foundation. The program included several stages, including preparation, coordination, consolidation, implementation, monitoring, and evaluation. The participants’ knowledge of food safety and food hygiene increased significantly from 52% prior to training to 96% after the training. Moreover, the ability to detect pesticide contamination in vegetables using LFI technology improved by 84%, rising from just 8% before training to 92% after training. All participants expressed interest in the UAD in Timor-Leste's future continuation of this training program.

Preparation and extraction property study of corn cob-like magnetic mosaic carbon materials derived from MOF-on-MOF composites

BackgroundLarge accumulations of pesticide residues in the environment eventually enter the human body with food. Based on magnetic solid-phase extraction (MSPE) technology, it is possible to achieve efficient extraction of trace pesticide residues in foodstuffs, and the construction of MSPE adsorbents with excellent magnetic properties and many active sites is still one of the main research topics. Based on this, we developed a new strategy for the preparation of "MOF-on-MOF" composites, which were carbonized and used as adsorbents for the extraction of pesticide residues in cereals. ResultsA novel corn cob core-shell composite Fe2O3@C@ZIF-8 was created by embedding ZIF-8 onto the surface of Fe2O3@C derived from MIL-88A(Fe), and used for the extraction of benzoylurea insecticides(BUs) from cereals. The adsorption behaviour between Fe2O3@C@ZIF-8 and BUs was investigated by static and kinetic experiments and the adsorption mechanism was elaborated. For the trace analysis of BUs, a magnetic solid-phase extraction combined with high performance liquid chromatography-ultraviolet detector (HPLC-UV) approach was also developed. Under the optimized experimental conditions, the limits of detection and quantification were 0.015–0.03 μg L−1 and 0.05–0.1 μg L−1, and the relative standard deviations for the intra-day and inter-day ranges were 1.82%–2.13 % and 3.85%–4.59 %, respectively. The spiked recoveries of the four cereals ranged from 82.72% to 104.45 %. After 10 cycles of use of Fe2O3@C@ZIF-8, the recoveries of BUs ranged from 77.90% to 96.74 %. SignificanceThe analytical method based on Fe2O3@C@ZIF-8 as adsorbent has a low limit of detection, a wide linear range and is highly applicable to the analysis of real samples. In addition, the strategy developed in this study for the preparation of thermoplastic polymer-assisted "MOF-on-MOF" composites has promising applications.

Pesticides in Agricultural Soils: Major Findings from Various Monitoring Campaigns in Switzerland.

Synthetic pesticides are widely applied in modern agriculture, where they are used against diseases, pests, and weeds to secure crop yield and quality. However, their intensive application has led to widespread contamination of the environment, including soils. Due to their inherent toxicity, they might pose a risk to soil health by causing harm to non-target organisms and disrupting ecosystem services in both agricultural and other exposed soils. Following the Swiss National Action Plan on the reduction of pesticide risks, Agroscope has conducted several soil monitoring studies that are briefly presented here. All of them resort to different multi-residue trace analytical approaches to simultaneously quantify up to about 150 modern pesticides by either accelerated solvent, or Quick, Easy, Cheap, Efficient, Rugged, Safe (QuEChERS) extraction, followed by separation and detection with liquid chromatography-triple quadrupole mass spectrometry. While partly still in progress, our investigations led to the following major findings this far: Multiple pesticides are commonly present in soils, with individual concentrations in agricultural soils often reaching up to a few tens of µg/kg. Pesticide occurrence and concentrations in agricultural soils primarily depend on land use, land use history and cultivated crops. Pesticides can prevail much longer than predicted by their half-lives, and were found in soils even decades after conversion from conventional to organic farming. Corresponding residual fractions can be in the order of a few percent of the originally applied amounts. We further found negative associations of pesticide residues with the abundance of beneficial soil life, underpinning their potential risk to the fertility of agricultural soils. Traces of pesticides are also detected in soils to which they were never applied, indicating contamination, e.g., via spray drift or atmospheric deposition. These results confirm the general notion of both scientists and legislators that prospective risk assessments (RA; as executed during registration and use authorization) should be confirmed and adjusted by retrospective RA (e.g., by environmental monitoring studies of currently used compounds) to jointly lead to an overall reduced environmental risk of pesticides.