Pesticide Residue Levels Research Articles

Determination of organochlorine pesticides from juice samples using magnetic biochar-based dispersive micro-solid phase extraction in combination with dispersive liquid-liquid microextraction

Analysis of pesticide residue levels in juice beverages is important to ensure safe consumption and avoid global trade concerns associated to pesticide contaminations. A simple, inexpensive and effective method was developed for the determination of organochlorine pesticides (OCPs) in bottled juice drinks using GC-MS. Sample pretreatment was performed using dispersive solid-phase microextraction (D-μ-SPE) for matrix desorption and dispersive liquid-liquid microextraction (DLLME) for analyte enrichment. In this study, an affordable and effective sorbent for the adsorption of OCPs from juice samples was synthesized from avocado seeds mixed with magnetic precursors for D-μSPE. The ground avocado seeds combined with a magnetic precursor nanocomposite were characterized using various instruments including scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) analysis. The solution obtained from D-μ-SPE desorption was used as a dispersant for the subsequent DLLME, which made the combination of D-μ-SPE with DLLME much easier. The effectiveness of the method was enhanced by optimizing the influential parameters in both D-μ-SPE and DLLME. Then after, the optimal values were determined for the real sample analysis. Accordingly, there was good linear dynamic range with a coefficient of determination (r2) ≥ 0.9989. The limit of detection and quantification were 0.02–0.69 and 0.06–2.10 ng/L respectively. The method showed high enrichment factors ranging from 96 to 313 with recoveries of 87–100 %. Intraday and interday precisions were ≤4 %. Compared with other reported methods, this method is a one-step, simple, cheap, fast, and environmentally friendly alternative and straightforward method for adsorbing organochlorine pesticides from sample solutions. These results demonstrates the high potential of the proposed method for the extraction and cleanup of contaminants in selected juices and other related samples.

Insecticidal Activity of Selected Essential Oils against Drosophila suzukii (Diptera: Drosophilidae).

The spotted wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), is an invasive polyphagous pest of soft-skinned fruit that has started to threaten small fruit production in Europe since 2008. High reproductive capacity, short generation time, and difficulties in visualizing early damage contribute to its rapid spread. Currently, the control strategy against D. suzukii mostly relies on treatment with synthetic insecticides. Keeping in mind that this pest causes the greatest damage during the harvesting period, control using chemicals is not recommended due to the increased risk of high pesticide residue levels in the fruit. With the aim of reducing the use of insecticides, there is a need for developing an environmentally safer way of control. Alternative solutions could rely on the use of essential oils (EOs), which can be used in conventional and organic production systems. Four essential oils, geranium (Pelargonium graveolens), dill (Anethum graveolens), Scots pine (Pinus sylvestris), and bergamot (Citrus bergamia), were assessed for their insecticidal effects using four different tests (contact toxicity, fumigant-contact toxicity, repellent effect, and multiple-choice tests). The EOs applied were dissolved in acetone at three different concentrations. The most promising one was the geranium essential oil, which had the best effect in all conducted tests, even at the lowest applied concentration. Geranium oil caused very high mortality (95%), even at the lowest concentration applied, after 24 h in the fumigant-contact test, and it caused a mortality of over 85% in the contact test. It was also noticed that geranium demonstrated a deterrent effect by repelling females from laying eggs for four days after at the lowest applied concentration. Scots pine and dill EOs have moderate to strong effects in most tests. The mortality of 100% was achieved for the highest applied concentration in the fumigant-contact and contact tests. Bergamot EO did not have any significant insecticidal activity. Geranium, Scots pine, and dill have great potential to be used as an environmentally friendly way of controlling D. suzukii as they exhibit deterrent, repellent, and insecticidal effects.

Characterization of Environmental Levels of Pesticide Residues in Household Air and Dust Samples near a Bioenergy Plant Using Treated Seed as Feedstock.

Exposure to neonicotinoid insecticides is associated with adverse human health outcomes. There is environmental contamination in Saunders County, Nebraska, due to the accumulation of fungicides and insecticides from a now-closed ethanol plant using seed corn as stock. A pilot study quantified environmental contamination in nearby houses from residual pesticides by measuring dust and air (indoor/outdoor) concentrations of neonicotinoids and fungicides at the study site (households within two miles of the plant) and control towns (20-30 miles away). Air (SASS® 2300 Wetted-Wall Air Sampler) and surface dust (GHOST wipes with 4 × 4-inch template) samples were collected from eleven study households and six controls. Targeted analysis quantified 13 neonicotinoids, their transformation products and seven fungicides. Sample extracts were concentrated using solid phase extraction (SPE) cartridges, eluted with methanol and evaporated. Residues were re-dissolved in methanol-water (1:4) prior to analysis, with an Acquity H-Class ultraperformance liquid chromatograph (UPLC) and a Xevo triple quadrupole mass spectrometer. We compared differences across chemicals in air and surface dust samples at the study and control sites by dichotomizing concentrations above or below the detection limit, using Fisher's exact test. A relatively higher detection frequency was observed for clothianidin and thiamethoxam at the study site for the surface dust samples, similarly for thiamethoxam in the air samples. Our results suggest airborne contamination (neonicotinoids and fungicides) from the ethanol facility at houses near the pesticide contamination.

Evaluation of the nutritional value and presence of minerals and pesticides residues in agro-industrial by-products to replace conventional ingredients of small ruminant diets

Fruit and vegetable production across the Mediterranean generates large volumes of by-products that can potentially lessen the livestock feeds deficit in some regions due to climate change effects and other socio-economic factors. However, the utilisation of agro-industrial by-products to their full potential is hindered by several factors such as variability in composition, limited development of preserving technologies and the presence of undesirable substances that may represent a risk for the animal or the final consumer. This work was conducted to study the nutritive value of a range of different alternative by-products from the Spanish agro-industry, assessing the potential to replace conventional ingredients often used in diets for small ruminants and the risk associated with the presence of pesticide residues and minerals. A total of 15 agro-industrial by-products commonly available in different regions of Spain were tested: three different types of apple pomace from three different varieties of apples (Perico, Regona, and Solarina), lemon pulp, avocado seed, broccoli, watermelon silage, olive cake, avocado cake, and six types of silages made with straw and a combination of different by-products (80/20 on fresh matter basis) from the intensive greenhouse horticulture: cucumber, tomato, pepper-cucumber mix (Pep-Cuc silage), aubergine-tomato mix (Aub-Tom silage), tomato-pepper-watermelon mix (Tom-Pep-Wat silage), and watermelon-melon-tomato mix (Wat-Mel-Tom silage). The study involved chemical characterization, including minerals and pesticides residues, and in vitro assessment of the ability to partially replace (10%, 20%, 30%, 50% and 100%) conventional ingredients in a diet for adult sheep (oat hay, barley and sunflower meal), depending on their chemical composition. The inclusion of by-products up to 30% replacement had not effect or improved some of the fermentation parameters and cucumber silage and apple pomace could successfully replace 100% of oat hay and barley, respectively, with only a significant reduction (P < 0.006) of rumen ammonia concentration. The mineral content was highly variable among the by-products with high values of Al in watermelon silage, Cu in olive cake and avocado by-products and Ni and Cr in olive cake. The pesticide residues assessment included 45 different types of compounds commonly used in crop production and three by-products had levels of pesticides residues above the legal limit: watermelon silage had traces of Chlorpyrifos (0.06 mg/kg DM), lemon pulp had Imazalil (0.09 mg/kg DM), and cucumber silage and Wat-Mel-Tom silages had Thiabendazole (0.04 mg/kg DM). Although all by-products showed potential to replace conventional ingredients from a nutritional perspective, the presence of high levels of some minerals and pesticides residues in some by-products requires regular analyses throughout the year or across batches before feeding them to animals.

Residue behavior and processing factors of thirteen field-applied pesticides during the production of Chinese traditional fermented chopped pepper and chili powder.

In this study, the fate, processing factors and relationship with physicochemical properties of thirteen pesticides in field-collected pepper samples during Chinese chopped pepper and chili powder production was systematically studied. The washing, air-drying, chopping and salting and fermentation processes reduced 24.8%-62.8%, 0.9%-26.4%, 25.1%-50.3% and 16.3%-90.0% of thirteen pesticide residues, respectively, while the sun-drying processing increased the residues of eleven pesticides by 1.27-5.19 fold. The PFs of thirteen pesticides were<1 in chopped pepper production and the PFs of eleven pesticides were more than 1 for chili powder production. The chopped pepper processing efficiency have most negative correlation with octanol-water partition coefficient. In contrast, the chili powder processing efficiency have most positive correlation with vapour pressure. Thus, this study can offer important references for assessment the pesticide residue levels in Chinese traditional fermented chopped pepper and chili powder production from fresh peppers.

Assessment of Organochlorines Pesticides Residues in Water, Fish and Sediment Samples from Wurbo Lake, Bali, Taraba State, Nigeria

Organochlorines pesticides (OCPs) have been used worldwide, particularly in many African countries as in Nigeria for the control of pests. OCPs are characterized by their bioaccumulation in the environment, especially in the food chain, where they find their way into the human body. The research was aim to estimate the residual concentrations of different OCPs in water, fish and sediment from Kundi Lake to find out the extent of pesticide contamination and accumulation. The water sample was subjected to liquid-liquid extraction method while the fish and the sediment samples were subjected to soxhlet extraction. The extracts were later analysed for organochlorines pesticide residues using Gas-Chromatography coupled with mass spectrometer (GC-MS). The average length, average weight and condition factor of the studied fish species were measured. The Mormyrus rume had the highest average length of 17.12±0.05 cm, and average weight of 195.36±0.05 g follow by Clarias gariepinus which had the average length of 16.83±0.01 cm, and average weight of 189.43±0.03 g. Tilapia zilli was the least species of fish sample with a length of 12.75±0.03 cm and average weight of 102.21±0.02 g. Also, all the fish species sampled in this present study had condition factors&gt;1. Based on the results obtained from all samples, it was found that the levels of organochlorine pesticides residues in water were generally below MRL as compared with FAO/WHO (0.5ppm). In fish samples, highest concentration of pesticide residues in Mormyrus rume follow by Clarias gariepinus, while the Tilapia zilli recorded low concentration of the pesticide residues. The Endosulfan II recorded high concentration of 4.68 ppm in Mormyrus rume follow by Endrin which recorded the concentration of 2.75 ppm, Aldrin 1.78 ppm and Atrazine 1.72 ppm all in Mormyrus rume. In Clarias gariepinus, Simazine 1.56 ppm follows by Endosulfan I 1.28 ppm while In Tilapia zilli, Endosulfan II 1.16 ppm follows by Atrazine 0.91 ppm and Beta Lindane 0.81 ppm. The results indicate that the area is contaminated with high levels of these pesticides in fish and sediment which may pose a great danger to the environment. Regular monitoring is therefore required to control the levels of pesticide residues in the water bodies.

Probe –integrated electrochemical sensing platform for measuring trace levels of parathion pesticides residues in water using Au- nanoparticles anchored Nafion nano composite modified glassy carbon electrode

Nanomaterial represents a principal driver to the adoption of electrochemical sensors for pesticides residues in water. Thus, the current strategy reports facile and highly sensitive electrochemical probe for monitoring parathion residues in water. The probe was based upon the use of Au nanoparticles (AuNPs) functionalized Nafion nanocomposites modified glassy carbon electrode (Au NPs/Nafion/GCE). The surface morphology, effective surface area and electrocatalytic performance of the Au NPs/Nafion/GCE were recorded and assigned using a scanning electron microscopy (SEM), cyclic voltammetry (CV) and electronic spectra. A straightforward protocol based upon combination of Au NPs/Nafion/GCE and square wave- adsorptive cathodic stripping voltammetry at pH 7.0 was established for parathion detection. The probe displayed two linear responses between the catholic peak current (ip,c) at − 0.8 V versus parathion concentrations over the ranges from 1.07 × 10−6 - 1.07 × 10−5 and 1.99 × 10−9 - 9.0 × 10−7 M with limits of detection (LOD) and quantification (LOQ) of 6.06 × 10−10 M and 2.0 × 10−9 M, respectively. The probe exhibited excellent reproducibility, repeatability with RSD of ± 0.5% (n = 5) at 8.0 × 10−7 M parathion. The probe was applied for parathion detection in water and validated by HPLC. The experimental Student texp and Fexp values were less than the tabulated ttab (2.78) and Ftab (6.39) at 95% probability.

Mitigation of pesticide residue levels in the exposed dermal regions of occupationally exposed farmworkers by use of personal protective equipment.

Unsafe pesticide handling practices with the limited use of personal protective equipment (PPE) by the Indian farming groups lead to an increased risk of exposure to pesticides. Therefore, a community-based follow-up study based on dosimeters, wipes, and hand-wash technique was carried out to evaluate the dermal exposure to pesticides and to analyze the impact of the usage of PPE on minimizing the exposure among the farmworkers of Rangareddy district, Telangana, India. Risk in terms of hazard quotient (HQ), hazard index (HI), and safety analysis as margins of safety was assessed. Farmworkers averaged 18 years of farming experience and showed resistance to adopting good agricultural practices. Ten pesticide residues were detected in concentrations ranging from 0.000 to 246 mg ml-1 in hand-wash, 0.000 to 198.33 ng cm-2 in patch dosimeter, and 0.000 to 1,740 ng cm-2 in wipe samples collected from farmworkers not using PPE. The second phase includes the intervention study results that revealed a significant reduction both in the concentrations and the number of pesticide residues detected in the hand-wash, patch, and wipe samples of the farmworkers who have used the PPE provided to them (p < 0.01). Furthermore, the probabilistic health risk assessment in terms of the HQ values ranged from 0.02 to 1029.82, and HI was >1, suggesting the non-carcinogenic risks associated with dermal exposure to pesticides among them. Additionally, the safety risk assessment in terms of the margin of safety suggests that they follow risky handling practices. The study confirms that farmworkers are exposed to pesticides and emphasizes the significance of using PPE in reducing the risk.

Enhancing the qualitative and nutritional properties of strawberry juice through chitosan treatment

SummaryStrawberry (Fragaria x ananassa Duch.) belongs to the Rosaceae family. The fruit is very beneficial, with a delicious taste, attractive colour, and high vitamin and mineral content. The effect of chitosan on juice's transparency and phytochemical properties from the Camarosa cultivar was evaluated. Using chitosan as a clarifying agent for strawberry juice significantly reduced turbidity, phenolic content, flavonoids, protein and antioxidant properties. In contrast, the quantity of soluble solids, titratable acidity, pH, folate, vitamin C, anthocyanin and carbohydrates showed no significant changes. Changes were also observed in the colour‐related parameters of the juice. In order to assess potential contamination in strawberry fruit, the levels of heavy metals and pesticide residues were analysed separately using ICP and GC–MS techniques. There was a significant reduction in the levels of Cu, As, Co, Pb and Cd in strawberry juice after treatment with chitosan. Reducing heavy metals in fruit juice using chitosan helps improve the fruit juice's safety, nutritional properties and health benefits. It can be posited that chitosan affords the production of a more nutritious and healthier fruit juice as compared to natural strawberry fruit. Using chitosan as a clarifying agent produces a juice with extraordinary clarity, improves the safety, health benefits and nutritional value, and produces a consumer‐friendly product.

Residue changes and processing factors of thirteen pesticides during different tomato pickle processes

Tomatoes grown in an experimental greenhouse were sprayed with 13 selected pesticides at the recommended field doses, and used for pickle processing. Three different pickle processing techniques (natural fermentation, starter added fermentation and canning) were applied during the trials. Two strains of Lactobacillus plantarum were used as starter cultures in starter added fermentation trials. Changes in pesticide residues, pH levels and microbiological populations were periodically analysed and processing factors (PFs) were calculated at the end of the processing period. Yeasts-moulds and enterobacteria were not detected in any of the trials. Mesophilic aerobic bacteria were detected during both fermentation treatments (natural and starter added), whereas lactic acid bacteria were only observed in starter added trials. The initial pH levels of brines in all treatments were measured as 2.7 at the beginning of the processes and changed depending on the type of treatment. Lower pH values were detected in starter added treatments. Following the harvest day, significant reductions were observed in pesticide concentrations during both types of fermentation (natural and starter added) trials (p < .01) with the exception of bifenazate and abamectin. But on the contrary, residue changes were not significant (p > .05) throughout the canning process. Since bifenazate and abamectin are more stable at lower pH, their residue levels were not affected by the methods applied during fermentation processes. Only PF of canning process for bifenazate was higher than 1 and calculated as 1.17. All other PF values were lower than 1, indicating that the treatments caused degradation of the active compounds. Processing methods affected the pesticide residue levels in different ways, as a result of various degradation mechanisms.

Determination of quizalofop-p-ethyl in onion: residual dissipation pattern, weed control efficiency, and food safety assessment under field conditions.

Monitoring pesticide residue levels becomes crucial to maintain quality and guarantee food safety as the consumption of onion green leaves and immature and mature bulbs (either raw or processed) rises. A field experiment was conducted for two consecutive seasons with quizalofop-p-ethyl (5% EC) at 50 and 100 g a.i. ha-1 to evaluate weed control efficiency and to determine terminal residues. Post-emergence application of fop herbicide at 100 g a.i. ha-1 kept the weed density and dry weight reasonably at a lower level and enhanced the productivity of onion with higher economic returns. A rapid, sensitive, and analytical method was developed using high-performance liquid chromatography (HPLC) with excellent linearity (r2 > 0.99). The limit of quantification for quizalofop-p-ethyl was established at 0.04 mg kg-1 with signal to noise (S/N) ratio ≥ 10. The method was successfully applied and initial quantified residues were in the range of 2.5-4.4 mg kg-1 irrespective of seasons and doses. Finally, the presence of targeted herbicide residues in harvested samples was confirmed by liquid chromatography tandem mass spectrometry (LC-MS/MS) under optimized operating conditions. Dietary risk assessment assured harvested onions were safe for consumption at the recommended dose. It also can be concluded that quizalofop ethyl did not adversely influence soil micro-organisms at standard rates of application.

Non-destructive detection and recognition of pesticide residue levels on cauliflowers using visible/near-infrared spectroscopy combined with chemometrics.

In this study, two prediction models were developed using visible/near-infrared (Vis/NIR) spectroscopy combined with partial least squares discriminant analysis (PLS-DA) and least squares support vector machine (LS-SVM) for the detection of pesticide residues of avermectin, dichlorvos, and chlorothalonil at different concentration levels on the surface of cauliflowers. Five samples of each of the three different types of pesticide were prepared at different concentrations and sprayed in groups on the surface of the corresponding cauliflower samples. Utilizing the spectral data collected in the Vis/NIR as input values, comparison and analysis of preprocessed spectral data, and regression coefficient (RC), successive projections algorithm (SPA), and competitive adaptive reweighted sampling (CARS) were used in turn to downscale the data to select the main feature wavelengths, and PLS-DA and LS-SVM models were built for comparison. The results showed that the RC-LS-SVM was the best discriminant model for detecting avermectin residues concentration on the surface of cauliflowers, with a prediction set discriminant accuracy of 98.33%. For detecting different concentrations of dichlorvos, the SPA-LS-SVM had the best predictive accuracy of 95%. The accuracy of the model based on CARS-PLS-DA to identify chlorothalonil at different concentration levels on cauliflower surfaces reached 93.33%. The results demonstrated that the Vis/NIR spectroscopy combined with chemometrics could quickly and effectively identify pesticide residues on cauliflower surfaces, affording a certain reference for the rapid recognition of different pesticide residue concentrations on cauliflower surfaces. PRACTICAL APPLICATION: Vis/NIR spectroscopy can detect the concentration levels of pesticide residues on the surface of cauliflowers and help food regulators quickly and non-destructively detect traces of pesticides in food, providing a guarantee for food safety. The technique also provides a basis for determining pesticide residue concentrations on the surface of other vegetables.

Organophosphate pesticide residues in surface water and bilih fish (Mystacoleucus padangensis Blkr.) in Lake Singkarak, West Sumatra

Organophosphate pesticide is a pesticide derivate that is used widely by farmers because it has a high killing power against insects and easily disappears from plants. Organophosphate pesticide residues can accumulate in the environment and also cause acute and chronic poisoning in humans. Singkarak Lake in West Sumatra Province is surrounded by many agricultural and farming areas. One of fisheries resources that can be affected by activities at those areas is Bilih fish (Mystacoleucus padangensis). The study aims to determine the levels of organophosphate pesticide residues in Singkarak Lake’s water and Bilih fish. Seven organophosphate pesticide compounds: Diazinon, Fenitrothion, Methidathion, Malathion, Chlorpyrifos, Parathion, and Profenofos were analyzed. In June 2021, surface water and Bilih fish samples were collected from 10 sampling locations in Singkarak Lake. The organophosphate pesticide in the samples was determined using gas chromatography. The results showed that residues were detected in water samples of four locations (Ombilin, Tikalak, Sumani, and Paninggahan), but not in the other six locations (Batu Taba, Sumpur, Guguak Malalo, Saniang Baka, Muaro Pingai, and Tanjung Mutuih) as well as below 1 ppb. Methidathion, Malathion, Chlorpyrifos, and Parathion were detected in lake water at range 2 to 8 ppb. Except for the Bilih fish sample from Ombilin, the majority of the samples contained organophosphate residues. Diazinon, Fenitrothion, Methidathion, Chlorpyrifos, Parathion, and Profenofos were the organophosphate derivate found in the fish samples. Malathion compound was not found. The organophosphate residue concentration in Bilih fish ranged from 2 to 70 ppb.

Monitoring residue levels of multiple types pesticides in chrysanthemum (Chrysanthemum morifolium Ramat) and its residue pattern in diet consumption

In this study, a modified preparation method named "Quick, Easy, Cheap, Effective, Rugged and Safe" (QuEChERS) was designed to detect six pesticide residues (fenthion, pendimethalin, trifloxystrobin, bifenazate, pyridaben, and pyraclostrobin) in 25 chrysanthemum (Chrysanthemum morifolium Ramat) samples by the gas chromatography-mass spectrometry (GC-MS) analysis. Prior to GC-MS analysis, extraction was performed using acetonitrile-2.5 % formic acid with European standard (EN) QuEChERS method extraction salts, and the matrix was purified with a combination of sorbent primary secondary amine/graphitized carbon black/octadecylsilane (PSA/GCB/C18). The limits of detection and quantification were then measured by applying matrix-matched calibration curves (R2 ≥ 0.999) in the ranges of 0.35–3.25 and 1.04–9.76 μg·kg−1, respectively. By quantitative analysis, the recoveries of pesticides ranged from 80.14 % to 98.57 % with the relative standard deviations < 10 % at the spiked levels of 0.01, 0.05 and 0.10 mg·kg−1. The transfer rates of pyraclostrobin in chrysanthemum to its infusion ranged from 11.38 % to 25.75 %. According to the favorable results, the method may be suitable for the quantitative detection of six chemical pesticides in chrysanthemums. Additionally, with a hazard quotient of 1.43 %, pyraclostrobin posed a negligible risk to human health.

Pesticide Residue Assessment on Vegetable Crops through Rapid Bioassay of Pesticide Residue in Nepal

The increasing use of pesticides has also raised the risk of higher pesticide residues in food. Also, the food commodities imported from India are considered to be very unsafe to consume because of their indiscriminate pesticide applications on crops. Sometime, this situation also occurs in Nepal food commodities. The research was carried to evaluate the residue level of carbamate and organophosphate pesticides in different vegetable commodities of Nepal origin and regularly imported from India. Pesticide residue was evaluated through Rapid Bioassay of Pesticide Residue analysis in 285 samples obtained from Bagmati Province, Lumbini Province and Sudurpaschim Province of Nepal and bordering areas of Koshi, Lumbini and Sudurpaschim Provinces. In laboratory test, most of vegetable crops were found to have pesticide residue in them. In Bagmati province, brinjal (17.29%), capsicum (16.6%), and chilli (18.12%); in Lumbini, brinjal (17%), cauliflower (15.8%), and potato (16.68%); in Sudurpaschim, broadleaf mustard (15.21%) and cauliflower (41.64%) were found relatively higher pesticide residues while potato (18.38%), tomato (29%), bean (32.52%), brinjal (39.25%), bitter gourd (14.37%) imported from India were found relatively higher pesticide residues.

Effects of Thiamethoxam and Fenvalerate Residue Levels on Light-Stable Isotopes of Leafy Vegetables.

Accurate identification of the rational and standardized use of pesticides is important for the sustainable development of agriculture while maintaining a high quality. The insecticides thiamethoxam and fenvalerate and the vegetables spinach, cabbage, and lettuce were used here as study objects. Descriptive analysis and primary reaction kinetic equations were used to analyze the changes in metabolic residues of the two insecticides after different numbers of application in three vegetables. The effects of pesticide residue levels on the δ13C, δ15N, δ2H, and δ18O values of vegetables were analyzed by one-way analysis of variance and correlation analysis. Partial least squares discriminant analysis (PLS-DA) was applied to build discrimination models of the vegetables with different pesticide residues based on stable isotopes. The results showed that the first degradation residues of thiamethoxam and fenvalerate in spinach, cabbage, and lettuce conformed to primary reaction kinetic equations, but the degradation half-lives were long, and accumulation occurred in the second application. The differences in the four stable isotope ratios in the control group of the three vegetables were statistically significant, and two-thirds of the stable isotope ratios in the three vegetables with different numbers of pesticide applications were significantly different. The δ13C and δ15N values of spinach, the δ13C, δ15N, and δ2H values of cabbage, and the δ13C, δ15N, δ2H, and δ18O values of lettuce were significantly correlated with different residues of thiamethoxam and/or fenvalerate applications. The control groups of the three vegetables, spinach-thiamethoxam-first, spinach-thiamethoxam-second, cabbage-thiamethoxam-second, cabbage-fenvalerate-first, and lettuce-thiamethoxam-first, were fully identified by PLS-DA models, while the identification models of other vegetables containing pesticide residues still need to be further improved. The results provide technical support for identifying the rational use of pesticides in vegetables and provide a reference method for guaranteeing the authenticity of green and organic vegetables.

INVESTIGATION INTO THE PESTICIDES RESIDUES IN SESAME, MILLET, RICE, AND GUINEA CORN GROWN AROUND THE HADEJIA-KOMADUGU-YOBE RIVER AREA IN YOBE STATE, NIGERIA.

Application of pesticides during crop production often results in pesticide residue, a significant source of heavy metals in the harvested crops. This raises concern for consumers' health due to the potentially deleterious effects of pesticides on animals, particularly humans. This study examined the levels of pesticide residues using a gas chromatography-mass spectrometry (GC-MS) system and heavy metal elements concentration using Atomic Absorption Spectrometry (AAS) in four food crops (Sesame, Millet, Rice, and Guinea corn) cultivated in (Gwio-Kura) Gashua and Hadejia towns in Nigeria. The results disclosed that Sesame was the only crop with Dichlorvos from both Gashua and Hadejia, surpassing the WHO's limit for pesticide residue concentrations, and that the Hadejia samples had higher levels than the Gashua samples. The study also detected traces of Cadmium (Cd), Lead (Pb), Nickel (Ni), and Manganese (Mn) in the crops, but they were below the permissible intake levels established by FAO/WHO. However, Arsenic (As) and Chromium (Cr) exceeded the FAO/WHO limits and may entail serious health problems such as kidney damage and cancer. Mercury (Hg) was not detected in any of the crops. Our findings suggest health authorities monitor and regulate heavy elements intake in food crops, especially those with high toxic contamination, to prevent adverse health effects such as the kidney disease on humans and animals, currently prevalent in the area.&#x0D;

Levels of organochlorine pesticide residues in fresh tomatoes from selected farming communities in Navrongo, Ghana

The levels of organochlorine pesticide (OCP) residues in tomatoes sourced from three agricultural communities in Navrongo (Bonia, Korania, and Nangalkenia) were analyzed using gas chromatography. A comprehensive analysis revealed the presence of nineteen (19) distinct organochlorine pesticides, with a minimum of five different residues detected in each tomato sample. The OCPs were detected within a range of 0.04 to 15.90 μg/kg. Remarkably, beta-hexachlorocylohexane (β-HCH) exhibited the highest concentration (15.90 μg/kg), while both cis-chlordane and trans-heptachlor epoxide displayed the lowest concentration (0.04 μg/kg) in Korania. In the Nangalkenia community, gamma-hexachlorocylohexane (δ-HCH) demonstrated the highest concentration (10.21 μg/kg), while trans-chlordane and o,p'‑Dichlorodiphenyltrichloroethane (o, p-DDT) exhibited the lowest concentration (0.04 μg/kg). Furthermore, within the Bonia community, p, p-Dichlorodiphenyltrichloroethane (p, p-DDT) displayed the highest concentration (8.25 μg/kg), whereas o, p-DDT and trans-heptachlor epoxide exhibited the lowest concentration (0.13 μg/kg). Notably, the analysis indicated that two (2) of the organochlorine pesticides, specifically β-HCH and δ-HCH, surpassed the Maximum Residue Limits (MRLs) established by the United Kingdom/European Commission (UK/EC). The results of the questionnaire survey unveiled a substantial proportion of illiterate farmers (54%), which potentially plays a significant role in the farmers' misuse or indiscriminate use of pesticides. Additionally, both the questionnaire responses and field visits provided insight into the specific types of pesticides employed by the farmers. These include karate, lambda, carbofuran, mancozeb, ridomil, sunpyrifos, kocide, cypermethrin, and dimethoate.

Residue levels of organophosphate pesticides and dialkylphosphates in agricultural products in Japan

High urinary levels of dialkylphosphates (DAPs), which are common structures of organophosphate pesticides (OPs), have been associated with several adverse health outcomes in human biomonitoring studies. Previous studies have indicated that dietary OP exposure and ingestion of environmentally degraded DAP, which is inactive with acetylcholinesterase, can lead to an increase in urinary DAP levels in the general population. However, the specific food sources contributing to the intake of OPs and DAPs have not been identified. In this study, we analyzed the levels of OPs and preformed DAPs in various food items. DAP levels were markedly high in certain fruits, such as persimmon, apple juice, kiwi, and mandarin. In contrast, only moderate levels of OPs were detected in these foods. Furthermore, the levels of OPs and DAPs were positively associated with vegetables, whereas no such association was observed in fruits. Increased consumption of certain fruits presumably leads to a marked increase in urinary DAP levels in individuals despite limited exposure to OPs, resulting in reduced reliability of urinary DAPs as a marker of OP exposure. Therefore, the possible effects of dietary habits and the resulting intake of preformed DAPs should be considered when interpreting biomonitoring data of urinary DAPs. Additionally, DAP levels in most organic foods were much lower than those in conventional foods, suggesting that the reduction in urinary DAPs by organic diet intervention may be mainly attributed to the reduced intake of preformed DAPs rather than reduced exposure to OPs. Therefore, urinary DAP levels may not be suitable indicators for evaluating ingested OP exposure.

Method Validation for Pesticide Residues on Rice Grain in Aceh Besar District, Indonesia Using Gas Chromatography-Electron Capture Detector (GC-ECD)

Analysis of pesticide residues in rice in Aceh Besar District using the Gas Chromatography – Electron Capture Detector (GC-ECD) method has been carried out. This study aims to validate the analytical method and determine the pesticide residue levels of Dichlorvos, Dimethoate, Bifenthrin, and λ-Cyhalothrin in rice samples. Rice samples in branded rice were taken from the Districts of Want Jaya, Indrapuri, Darussalam, Suka Makmur, Simpang Tiga, Kuta Baro, and ground using a grinder. The powder sample was extracted by the QuEChERS method and analyzed by GC-ECD. The results of the linearity test have met the requirements with the coefficient of determination (R2), which is an average of 0.98. The LOD values ranged from 0.013 to 0.017 mg/kg, while the LOQ ranged from 0.022 to 0.079 mg/kg. The results of precision and reproducibility (% RSD, n = 6) show the values of 0.56 - 1.26% and 1.14 - 2.19%, respectively, and the accuracy value (%Recovery) shows the results of 99.71 - 101.84%, with an RSD value of 2.42 - 3.59%, meet the requirement of 20%. The results of the analysis of the sample showed that sample A had a large %Recovery value in the Dichlorvos analyte, namely 139.10%, with the calculation that the Dichlorvos analyte contained 0.0206 mg/Kg. This value has not passed the MLR set by the European Food Safety Authority, which is 0.2 mg/Kg. In the other rice samples, no pesticide residue analytes were detected. The calculation of %Recovery of each analyte in the spiked sample ranged from 80-101%, which indicated that the pesticide residue analysis carried out had good accuracy, namely the requirement of 70-120%.