Organophosphate Pesticide Residues Research Articles

Organophosphate pesticide residues in fruits and vegetables in Nigeria: prevalence, environmental impact, and human health implications.

Pesticides have become indispensable in modern agriculture, aiding in crop protection, and ensuring food security. However, their extensive use has raised concerns about environmental contamination and human health risks. This manuscript reviews the prevalence of organophosphate pesticide (OPP) use in Nigerian agriculture and explores methods for detecting pesticide residues in fruits and vegetables. Despite the critical role of pesticides in safeguarding crop yields, the lack of regulatory enforcement and monitoring in Nigeria poses significant challenges. The review underscores the importance of understanding the health implications of pesticide residues in food. While acute and sub-chronic health effects of OPP exposure have been studied, there remains a need for a focused review of the long-term impacts, particularly in the context of limited regulatory oversight. Additionally, the manuscript highlights gaps in knowledge regarding the effects of pesticides on biodiversity, ecosystems, and vulnerable populations such as children, pregnant women, and the elderly. Recommendations include longitudinal studies to assess cumulative and delayed health consequences, systematic reporting of poisoning incidents, and routine analysis of food products to ensure safety. By addressing these gaps, a more comprehensive understanding of the consequences of OPP usage in Nigeria can be achieved, facilitating the development of effective risk management strategies to protect both the environment and public health.

Pesticide residues in tropical agricultural soils: Distribution, seasonality, and earthworm ecological risk

Soil contamination by pesticide residues is associated with agricultural intensification in tropical regions and endangers human health and the environment. A mixture of pesticide residues and their degradation products persist in agricultural soils and represent a risk to soil organisms. In this study, we aimed to investigate the concentration and distribution of organochlorine (OC) and organophosphate (OP) pesticide residues in agricultural soils where the industrial cultivation of maize and soybeans is intensively carried out, at three depths (0–5, 5–15, and 15–30 cm) and during two seasons (rainy and dry). Likewise, we performed the ecological risk assessment of those found pesticide residues on two earthworm species, Eisena fetida, and Aporrectoda calagionsa. We calculated the Toxicity-Exposure Ratio (TER) using Predicted no Effect Concentrations (PNEC) and measured concentrations in soils, for identifying the risk of pesticide residues separately. The Risk Quotient (RQ) method was used to evaluate the ecological risk of pesticide residue mixtures in soils from each cropping system. Endrin ketone and dieldrin were the pesticide residues with the highest frequency of detection. The highest concentration in the study was found in a soil sample from maize crops in the dry season at 15–30 cm depth (2917 ng/g). The pesticide mixture from soil samples belonging to maize (0–5 cm) and soybean (5–15 cm) crops in dry season posed the highest ecological risk for A. caliginosa with 100 %, and a maximum RQ of 82.2. Endrin ketone is the OC that contributed most to the overall toxicity of the pesticide mixture in soil samples from maize crop and dieldrin in soil samples from soybean crop. Among OP, disulfoton contributed most to RQsite in soybean crop and methyl parathion in maize crop. Results pointed out the need to apply alternatives to remediate obsolete pesticide residues and restrict the use of methyl parathion and disulfoton in maize and soybean crops, to reduce the ecological risk that represent for earthworms.

Highly sensitive detection of organophosphorus pesticides in water using a carboxyl-functionalized magnetic covalent organic framework

The development of novel methods for the precise quantification of organophosphate pesticides (OPPs), with enhanced accuracy, sensitivity, and efficiency, is crucial for environmental monitoring and human health risk assessment. In this study, Fe3O4@SiO2@COF-COOH magnetic core–shell nanoparticles were synthesized by coating a carboxyl-functionalized covalent organic framework (COF-COOH) onto the surface of amino-modified silica-coated iron(III) oxide particles (Fe3O4@SiO2-NH2). The incorporation of carboxyl groups, covalent organic framework and magnetic properties imparted superior performance to the adsorbent in magnetic solid-phase extraction (MSPE) of polar compounds from complex sample matrices. An analytical method based on Fe3O4@SiO2@COF-COOH coupled with GC–MS/MS was developed for the determination of eight organophosphate pesticide residues in river water near farmland. The established method displays good linearity in the range of 0.1–500 ng/mL for four OPPs and 1–2000 ng/mL for the other four, with correlation coefficients between 0.9903–0.9983. The LODs (S/N = 3) and LOQs (S/N = 10) were determined to be in the ranges of 0.53–9.6 ng/L and 1.8–31.9 ng/L, respectively. The adsorption mechanism was characterized by density functional theory calculations. Furthermore, the established method was successfully applied to analyze the distribution of trace OPPs in real river water samples collected from various cities in Henan Province. Its rapid, straightforward, and efficient ability to enrich trace levels of OPPs from complex real-world samples makes it a valuable tool for environmental monitoring, food safety, and human health management.

High-sensitive detection of organophosphate and carbamate pesticide residues in milk based on bioluminescence method

Organophosphorus pesticides (OPs) and carbamate pesticides (CBs) are the most commonly used pesticides in agricultural cultivation. The pesticide residues in plant products can easily enter dairy cows through feed, resulting in the pesticide low-concentration residues in milk. Traditional acetylcholinesterase (AChE) inhibition-based colorimetric methods have low sensitivity and could not satisfy the detection of low-concentrations of OPs and CBs residues in dairy products. In this study, we combined firefly luciferase (FLuc)-mediated bioluminescence with the inhibition of AChE-catalyzed substrate activity by pesticides to develop a highly sensitive and rapid method for detecting OPs and CBs residues in milk. AChE breaks down D-luciferin acetate to produce D-luciferin, which is recognized by the FLuc and emits luminescence in the presence of ATP. However, the presence of OPs and CBs inhibits AChE, causing the reduction or disappearance of the luminescence signal. The luminescence signal can be detected using a hand-held luminescence photometer, eliminating the need for large instrumentation. The AChE-FLuc system accurately detected OPs and CBs in milk within 30 min, with detection limits of 7.89 ng/mL and 1.75 ng/mL, respectively. The sensitivity of this method is approximately ten times higher than that of traditional AChE inhibition methods, meeting the pesticide residue limits in milk set by China and the European Union.

Organophosphate, carbamate and synthetic pyrethroid pesticide residues in muscle tissues of fish from Loktak Lake, a Ramsar Site in Manipur, India

The muscle tissues of Channa punctatus and Anabas testudineus collected from the Loktak Lake (a Ramsar site) and its three major feeder rivers in Manipur, Northeastern India, were analyzed using high-performance liquid chromatography for the presence of residues of organophosphorus, carbamate, and synthetic pyrethroid pesticides. Pesticide residues of all the three types were detected in the fish tissues. Pesticide residues in Channa punctatus ranged from 0.002 – 0.043 µg g-1, and from 0.008 –0.027 µg g-1in Anabas testudineus from Loktak lake in pre-monsoon and post-monsoon seasons. Pesticide residues were detected only in Anabas testudineus (0.002 – 0.078 µg g-1) in Nambul river, while these were detected only in Channa puctatus (0.001 – 0.032 µg g-1) in Moirang river. In Nambol river, pesticide concentrations ranged from 0.002 – 0.026 µg g-1 in Channa punctatus, and from 0.004 – 0.005 µg g-1 in Anabas testudineus. Among the five pesticides detected, concentrations of dichlorvos residues detected in the present study (0.027 and 0.032 µg g-1 wet weight) exceeded the Codex Alimentarius maximum residue limit (MRL) of 0.01 mg kg-1 for animal tissues. The rest of the compounds were within the MRL. None of the pesticide residues was detected in the two fish species collected from the control or reference site. The present study indicates that pesticide contamination is emerging as a threat to the water quality and aquatic biodiversity of Loktak Lake, which calls for more detailed studies on the extent and magnitude of these threats.

Highly conductive Ti3C2 MXene-supported CoAl-layered double hydroxide nanosheets for ultrasensitive electrochemical detection of organophosphate pesticide fenitrothion.

A novel electrochemical method is presented for ultrasensitive detection of the organophosphate pesticide (OPP) fenitrothion by using Ti3C2 MXene/CoAl-LDH nanocomposite as the electrode modifier. The Ti3C2 MXene/CoAl-LDH nanocomposite is synthesized by growing CoAl-LDH in situ on MXene nanosheets. The combination of two ultrathin 2D materials provides more active sites, larger specific surface area, superior adsorption properties, and better electrical conductivity, which leads to rapid electron-transfer and mass-transfer between the substrate electrode and analytes when it is acted as the electrochemical sensing material. In addition, through the chelation of phosphate groups with the Ti defect sites enriched in MXene, OPP is adsorbed on the electrode. Consequently, the corresponding modified electrode gives rise to a wide linear response range of 0.03 ~ 120μmol/L for the differential pulse voltammetry detection of fenitrothion with a low detection limit of 5.8nmol/L (3σ). The method offers good repeatability, stability, selectivity, and practicability for real samples. This strategy provides a reference platform for the electrochemical monitoring of trace OPPs residue by using MXene/LDH-based nanocomposites.

Evaluation and implications of organophosphate pesticide residues in cabbage (Brassicaoleracea)

The improper application of pesticides in cultivating vegetables has resulted in the buildup of pesticide residues on vegetables. This study evaluated organophosphate pesticide residue levels in cabbage with specific objectives of investigating the varieties of organophosphate pesticides employed by farmers and their awareness, assessing residue levels on cabbage using semi-structured questionnaires, and determining the distribution of pesticide residues within the layers of the cabbage head using 50 cabbage samples randomly collected from farmers from 14 cabbage-producing communities. The findings indicated that 98 % of the farmers applied pesticides in the morning, whereas 24 % preferred evening application. Meanwhile, 22 % applied pesticides twice in a day. Also, 18 % combined pesticides, 40 % applied 20 ml during the application, 72 % chose a particular pesticide based on the expected efficiency, 46 % applied pesticides between 1 and 5 times in a season and 66 % sprayed between 7 and 14 days. Pyrinex 48 EC and Perferthion emerged as the predominant organophosphates, with usage rates of 10 % and 12 % respectively. Also, eleven (11) organophosphate pesticide residues were identified in the cabbage samples. Profenofos and chlorpyrifos exhibited the highest concentrations of pesticide residues, with levels reaching 0.02 mg/kg, with 56.6 % of the samples containing chlorpyrifos pesticide residue. Nevertheless, all the identified pesticide residues did not exceed the maximum residue limits for cabbage. The study analysis disclosed the presence of various organophosphate pesticide residues in the first 10 layers of cabbage. However, it was noted that the innermost layers might not contain any detectable pesticide residues. The findings highlight the need for farmers to use pesticides judiciously and follow recommended application practices to minimize vegetable residues.

Organophosphate pesticide residue impact on water quality and changes in macroinvertebrate community in an Afrotropical stream flowing through farmlands.

River Chanchaga has experienced significant agricultural practices around its catchment, which involved the indiscriminate use of pesticides. However, residents of the study area are not well aware of the negative impact of pesticides on water quality and macroinvertebrates. In this study, the first report on the influence of organophosphate pesticide contamination on the abundance of the macroinvertebrate community was provided. Sampling for the determination of organophosphate pesticide residues was carried out during the peak of the two seasons, while macroinvertebrates and physicochemical variables were observed for 6 months. We examined 11 organophosphate pesticide residues using gas chromatography coupled with mass spectrometry, 12 water quality variables, and 625 macroinvertebrate individuals. The concentration of recorded organophosphate pesticide residues ranged from 0.01 to 0.52 μg/L. From the Canonical Correspondence Analysis plot, malathion, chlorine, and paraffin show a positive correlation with Unima sp., Hydrocanthus sp., Chironomus sp., and Potadoma sp. At station 3, depth shows a positive correlation with Biomphalaria sp. and Zyxomma sp., indicating poor water quality as most of these macroinvertebrates are indicators of water pollution. Diuron and carbofuran show a negative correlation with Lestes sp. and Pseudocloeon sp., and these are pollution-sensitive macroinvertebrates. The total mean concentration of organophosphate pesticide residues was above international drinking water standards set by the World Health Organization except for paraffin, chlorpyrifos, and diuron. In conclusion, the observations recorded from this research are useful in managing pesticide applications around the river catchment.

A Review on Extraction and Chromatographic Techniques for Organophosphate Pesticidal Residue Analysis in Paddy and Rice Bran

Organophosphorus pesticides (OPPS) are extensively employed in agricultural techniques and may expose people to them via food intake. We offer an analytical approach for detecting OPPS in paddy, rice grains and or rice bran that combines solid-phase extraction with a high-performance liquid chromatography detector. Acetonitrile extraction was used before SPE–HPLC–MSMS to isolate specific residues, which helped decrease matrix disruptions and identify a broad array of numerous residues in rice grains. Accordingly, ranges of quantitative determination ranged from 0.01mg/kg to more than 1.0 mg/kg, with coefficients extending from 0.995 to more than 0.999. At three stimulating intensities, high recuperation was reported, suggesting excellent precision. The relative SD of all residues confirmed the technique’s accuracy. Using this, various OPPS were quantified, ranging from just below to maximum permissible limits to exceeding the limit. According to a sample study of different rice grain varieties accessible in the international market. This study focuses on the techniques of organophosphate pesticide residue extraction from paddy and rice ban. The study further discusses chromatographic techniques for the same.

Highly Sensitive and Rapid Screening Technique for the Detection of Organophosphate Pesticides and Copper Compounds Using Bifunctional Recombinant TrxA-PvCarE1.

Enabling the detection of organophosphate pesticide (OP) residues through enzyme inhibition-based technology is crucial for ensuring food safety and human health. However, the use of acetylcholinesterase, the primary target enzyme for OPs, isolated from animals in practical production poses challenges in terms of sensitivity and batch stability. To address this issue, we identified a highly sensitive and reproducible biorecognition element, TrxA-PvCarE1, derived from red kidney beans and successfully overexpressed it in Escherichia coli. The resulting recombinant TrxA-PvCarE1 exhibited remarkable sensitivity toward 10 OPs, surpassing that of commercial acetylcholinesterase. Additionally, this approach demonstrated the capability to simultaneously detect copper compounds with high sensitivity, expanding the range of pesticides detectable using the traditional enzyme inhibition method. Spiking recovery tests conducted on cowpea and carrot samples verified the suitability of the TrxA-PvCarE1-based technique for real-life sample analysis. In summary, this study highlights a promising comprehensive candidate for the rapid detection of pesticide residues.

Biochemical Response of the Endogeic Earthworm (Balanteodrilus extremus) Exposed to Tropical Soils

This work evaluated the biochemical responses of the endogeic earthworm Balanteodrilus extremus exposed for 14 and 48 days (d) to soils collected from two tropical agricultural systems: maize-sorghum (MS) and soybean-sorghum (SS). A soil without agricultural management (WAM) and the use of pesticides was selected as a reference. The presence of organochlorine (OC) and organophosphate (OP) pesticide residues was quantified in MS and SS soils. Biomarkers of detoxification [glutathione S transferase (GST)], neurotoxicity [acetylcholinesterase (AChE)] and oxidative stress [superoxide dismutase (SOD), catalase (CAT) and lipoperoxidation (LPO)] were evaluated in B. extremus. The concentration of OP pesticide residues was higher in SS than in MS. Activity of AChE in B. extremus exposed to SS soil for 14 d was significantly more inhibited (78%) than in MS soil (68%). B. extremus has been shown to be a good bioindicator of contaminated soils in tropical regions.

Pesticide residue exposure effect on health, growth, and development among children from agricultural area

Nowadays, the exposure to pesticides has become a matter of public health concern. The primary and secondary take-home exposure of pesticides may influence the health of communities. Farmworkers’ families generally live close to agricultural areas, which may increase the risk of residential pesticide exposure. Pesticide exposure affects children more than adults. Environmental quality drives the shifting patterns of children’s major health problems, from infectious to chronic diseases. Children’s developing organs may be exposed to low-dose concentrations of environmentally disruptive pesticides such as organophosphates, organochlorines, carbamates, and pyrethroids. Several groups of pesticide metabolites induce and inhibit growth and development in children. Potential health problems such as chronic respiratory disease, asthma, and wheezing in children were more often reported from agricultural communities than children from rural areas. Children who were in contact with pesticides during both their prenatal development and childhood reported diminished cognitive scores. This can be attributable to the elevated levels of pesticides found in their urine, which have been extensively documented. Diammonium phosphate (DAP) metabolites as one of the organophosphate pesticides (OPPs) residues correlate with high KIM-1 levels in urine, significantly leading to chronic kidney disease. DNA damage may be A potential reported effect in children from agricultural communities. Thus, to ensure children’s health and development, it is necessary to strengthen the impact of pesticide studies on children.

Evaluation of Organophosphates Residue in Stored Cereals from Some Selected Markets in Jalingo, Nigeria

Cereal grains such rice, sorghum, maize and millet among others are the staple foods in large parts of the world, supplying most of the energy and bulk in diets. Pesticide residue analysis in cereals from the various sampling locations for this dissertation revealed the following organophosphate pesticide residue were present in cereals analyzed Dichlorvos, Diazinon, Phorate sulfon, Malathion, Phorate, Chloropyrifos, Methyl Parathion, Profenofos, Ethion, Dimethoate, Phorate Sulfoxide, Phosalone, Edifenfos, Fenitrothion and Chlorofenvinfos. The presence of pesticide residues is detected in the samples of cereals (Rice, Maize, Millet and sorghum) analyzed. This could be as a result of high utilization of various pesticides during plant, cultivation and storage thus leading to the bioaccumulation of this substance in the individual cereals. It indicates high levels of non-carcinogenic risk associated with the life time consumption of cereals produce and sold within this region. Based on findings from this study’s, I hereby make the following recommendations. Regulatory agencies in Nigeria should step up efforts to ensure compliance with the ban on these chemicals. Farmers and other pesticide users also need to be educated on the dangers of using banned products and on the over application of these pesticides. Furthermore, farmers should be educated on the properly usage of these chemical product, during plant, harvest and storage. Also, manufacturers of these chemicals should produce less toxic pesticide using organic materials in other to prevent the health risk associated with chemical pesticide and their residues in food crops and the environment.

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.

Organophosphate Pesticide Residues in Food Products in Kenya and their Chromatographic Detection: A Systematic Review

Organophosphate pesticides are used worldwide to control several pests and meet food demand. These chemicals harm non-target animals and people when misused. Thus, they are a health and environmental concern. The purpose of the systematic review was to synthesise the amount, breadth, and quality of evidence from empirical studies concerning the presence, type, and quantity of OPs in food products in Kenya. A systematic review was done by following the PRISMA protocol. For the identification of studies, the following databases were used: Google Scholar, Web of Science, Scopus, and PubMed. The study focused on peer-reviewed articles published between January 2001 and August 2022. Twelve studies met the inclusion criteria for the scoping review. The main methods used in detecting and quantifying organophosphates in the studies were High-Performance Liquid Chromatography (HPLC) and Gas Chromatography-Mass Spectrometry (GC-MS). Most studies (86.67%) reported significant levels of OPs in food products, exceeding the MRLs and the Acceptable Daily Intake (ADIs) set by the World Health Organization. Six of the studies (50%) reported the presence of OPs in plant products (vegetables, cereals, and fruits), while three (25%) found residues in animal products (milk and meat). The most notable OP compounds detected were chlorpyrifos, acephate, profenofos, diazinon, omethoate, and dimethoate. Most of the food samples in the reviewed studies presented contamination, making them a significant risk to human health due to bioaccumulation. Studies done in Kenya for the last 20 years continue to report high levels of organophosphate residues and their metabolites in food products, both from plant and animal origin. Although the residues are below MLRs in some samples, they can accumulate at higher levels in humans, becoming a severe health risk

Concentration levels and risk assessment of organochlorine and organophosphate pesticide residue in selected cereals and legumes sold in Anambra State, south-eastern Nigeria

Abstract The levels of organochlorine and organophosphate pesticide residues in selected cereal crops (beans, cowpea, millet, maize, sorghum, and rice) purchased from major markets in Anambra, south-eastern Nigeria, were assessed and compared with established MRLs. The QuEChERS (quick, easy, cheap, effective, rugged, and safe) method was used for extraction and clean-up of pesticide residues. Thereafter detection and quantification were done using GC/MS. The result reveals that the analysed grain samples contained some organochlorine pesticides and organophosphates. The organochlorine was most dominant followed by the organophosphates. Organochlorine pesticide residues varied from 0.048 to 0.298 mg/kg in beans, BDL to 0.398 mg/kg in cowpea, 0.018–0.337 mg/kg in maize, 0.023–0.375 mg/kg in millet, 0.058–0.415 mg/kg in sorghum and 0.045–0.442 mg/kg in rice while organophosphate pesticide residue varied from BDL to 0.315 mg/kg in beans, BDL to 0.113 mg/kg in cowpea, BDL to 0.228 mg/kg in maize, BDL to 0.253 mg/kg in millet, BDL to 0.218 mg/kg in sorghum and BDL to 2.1 35 mg/kg in rice. Highest concentration of endosulphan II (0.442 mg/kg) was detected in rice, followed by aldrin (0.415 mg kg−1) in sorghum and endosulphan II (0.40 mg/kg) in sorghum. The pesticide toxicity index (PTI) was above one (1), whereas health index (HI) was less than one (1) and cancer risk were within USEPA reference guideline for crops indicating children will have greater health effect than adults. Hence, strict monitoring and control of pesticide residues in agricultural products is advocated.

Degradation effects on dichlorvos by a biocontrol strain, Trichoderma atroviride T23

Excessive use of organophosphate pesticides (OP), such as dichlorvos, in farming system poses a threat to human health through potential contamination of environment. To date, biodegradation has been prospected most promising approach to eliminate environmental OP residues. Trichoderma species as a biological control microorganism is often exposed to the chemical pesticides applied in environments, so it is necessary to understand the mechanism of degradation of dichlorvos by Trichoderma. In this study, dichlorvos significantly inhibited the growth, sporulation and pigmentation of T. atroviride T23, and the dichlorvos degradation activity of T23 required the initial induction effect of dichlorvos and the culture conditions, including the nutrient and pH values of the medium. Various changed primary and secondary metabolites released from T23 in the presence of dichlorvos were speculated as the energy and antioxidants for the strain itself to tolerate dichlorvos stress. The results showed that T23 could produce a series of enzymes, especially the intracellular enzymes, to degrade dichlorvos. The activities of the intracellular enzyme generated by T23 were differentially changed along time course and especially relied on initial dichlorvos concentration, ammonium sulfate and phosphate added in the medium. In conclusion, some dichlorvos-induced chemical degradation related enzymes of T23 were proved to be involved in the degradation of dichlorvos.

Magnetic Relaxation Switching Immunosensors via a Click Chemistry-Mediated Controllable Aggregation Strategy for Direct Detection of Chlorpyrifos.

Chlorpyrifos (CPF) is the most frequently found organophosphate pesticide residue in solid food samples and can cause increasing public concerns about potential risks to human health. Traditional detection signals of such small molecules are mostly generated by target-mediated indirect conversion, which tends to be detrimental to sensitivity and accuracy. Herein, a novel magnetic relaxation switching detection platform was developed for target-mediated direct and sensitive detection of CPF with a controllable aggregation strategy based on a bioorthogonal ligation reaction between tetrazine (Tz) and trans-cyclooctene (TCO) ligands. Under optimal conditions, this sensor can achieve a detection limit of 37 pg/mL with a broad linear range of 0.1-500 ng/mL in 45 min, which is approximately 51-fold lower than that of the gas chromatography analysis and 13-fold lower than that of the enzyme-linked immunosorbent assay. The proposed click chemistry-mediated controllable aggregation strategy is direct, rapid, and sensitive, indicating great potential for residue screening in food matrices.

Temporal evolution of organochlorine and organophosphate pesticide residues in wells in the Akkar Region (Lebanon).

The Akkar plain is the second largest agricultural area in Lebanon. This region produces huge amount of regular crops such as maize, fruits, and vegetables. In order to protect the crops, farmers use large quantities of many pesticides (including authorized and prohibited molecules) without respecting the recommended doses. In this work, we wanted to study the evolution of OCP and OPP residues at 3-year intervals in water wells in the Akkar region. Twenty OCPs and 8 OPPs were monitored in eight wells in different villages in the plain and mountains of Akkar. Solid phase extraction (SPE) method was used for pesticide extraction, followed by gas chromatography-mass spectrometry (GC-MS) analysis. The results revealed an increasing concentration of OCPs and OPPs in groundwater over the last 3years (between 2017 and 2019-2020). This increase in contamination is due to the uncontrolled and still unregulated (by the authorities) use of pesticides, and also to the introduction of new crops. The concentrations found in groundwater confirm that some banned pesticides are still widely used. The calculation of the theoretical pesticide intake suggests that pesticide concentrations in Akkar represent a greater health risk for the population consuming well water during the rainy season.

Assessment of organophosphate pesticide residues in environmental media of Araromi farm settlement, Osun State, Nigeria.

The aim of the study was to assess the occurrence and distribution of organophosphate compounds residue in soil, surface water, sediment, and banana crops in Araromi farm settlement, Osun State, Nigeria. Organophosphate pesticide residues were determined using a gas chromatography equipped with Flame-Ionization Detection (GC-FID) in 16 soil samples from cocoa and banana farms, 6 water and sediment samples each, and 8 banana samples from 4 farms in the study site. Fourteen organophosphate compounds were detected (acephate, omethoate, dementon-s-methyl, dimethoate, tolcofos-methyl, pirimiphos-methyl, malathion, chlorpyrifos, methidathion, prothiofos, profenofos, ethion, azinphos-methyl and pyrazophos). Tolclofos-methyl, pirimiphos-methyl and prothiofos were detected in all the soil and sediment samples with concentration ranges of 1.9-12.9, 2.25-6.98 and 3.38-9.89 mg/kg respectively in soil and 8.13-9.83, 2.82-25.1 and 3.70-19.5 mg/kg respectively in sediment. Dimethoate, pirimiphos-methyl and prothiofos with concentration ranges, 0.06-0.28, 0.09-0.18 and 0.16-6.11 mg/L respectively were mostly detected in water samples while dimethoate, tolcofos-methyl, malathion, methidathion, prothiofos, ethion and azinphos-methyl compounds were detected in all the banana samples with concentration ranges, 3.40-12.0, 1.82-6.26, 5.73-9.48, 29.7-145, 8.24-20.1, 3.87-9.35 and 3.66-12.2 mg/kg respectively. The organophosphate mean residue concentrations were mostly significantly higher than the Maximum Residue Limits (MRL) at p<0.05. Across the three samples, only pirimiphos-methyl was significantly higher in water samples, omethoate in sediment; acephate, dementon-s-methyl and chlorpyrifos in banana were also not significantly higher at p<0.05. A strong positive significant correlation was observed between the organophosphate compounds in the banana and water samples (R=0.77, p=0.002) at p<0.05. The occurrence of organophosphate compounds in concentrations above MRLs may pose serious environmental and health risks.