Organophosphorus Pesticide Residues Research Articles

Evaluation of cumulative exposures to multiple pesticide residues in three characteristic fruits in the Northwest of Iran: a risk assessment using Monte Carlo Simulation

This study was conducted to monitor and evaluate the health risks of multiple organophosphorus pesticide residues in three characteristic fruits of Maragheh district, East Azerbaijan province. The Monte Carlo method was used to quantify the possible non-carcinogenic health risks associated with pesticide residues in adults and children. The residues of 17 pesticides in 36 samples were analysed using the QuEChERS extraction method coupled with gas chromatography-mass spectrometry (GC/MS). Residues of 13 pesticides (76.47%) were detected in grape samples and 15 pesticides (88.23%) in apricot and plum samples. The maximum level found in grape samples was due to chlorpyrifos with 1.2 mg/kg, and in apricot and plum samples to diazinon with 1.6 and 1.3 mg/kg, respectively. All grape, apricot and plum samples contained at least ten pesticides with levels exceeding the Iranian and EU Maximum Residue Limits (MRLs). The processing factor for washing treatment in grape, apricot and plum samples was less than 1, ranging from 0.53 to 0.69. Chlorpyrifos with values of 0.064 and 0.256 in the grape samples and diazinon with values of 0.0443 and 0.177 in the apricot samples and values of 0.0263 and 0.105 in the plum samples contain the highest hazard quotients (HQ) for adults and children, respectively. The cumulative risk assessment due to exposure to several pesticide residues suggests that there is no significant health risk for adults (HI < 1). However, consumption of unwashed grapes may cause adverse effects in children (HI = 1.48). However, for further research, a comprehensive longitudinal study is suggested to assess the long-term effects of exposure to pesticides especially for children.

A novel portable in situ analyzer for highly sensitive monitoring of organophosphorus and carbamate pesticides in food and environment

The presence of excessive residues of organophosphorus (OPs) and carbamate (CPs) pesticides in food and the environment poses a significant threat to human health and ecological sustainability. Herein, we reported a dual-readout, portable, and highly sensitive photoelectric analyzer (DPHP-analyzer) to achieve rapid and accurate monitoring of OPs and CPs. The dual signal strategy is mainly achieved by controlling the activity of acetylcholinesterase (AChE) in the presence of OPs to catalyze acetylthiocholine (ATCh) and generate thiocholine (TCh), which specifically induced the conversion of colorless Ellman's reagent (DTNB) into yellow 5-thio-2-nitrobenzoic acid (TNB). Simultaneously, the utilization of positively charged TNB as an absorber can induce a dynamic fluorescence quenching effect based on energy transfer mechanism. Fully cooperating with the above mechanism, a CD like, disposable array-based chip manufactured by 3D printing (CD-AN-chip) was designed and integrated to deliver reagents. By use of this dual-output strategy, the analyzer and chip can provide good sensitivity and selectivity for the monitoring of diazinon and carbendazim (case analysis) with a LOD 0.38 ng/mL for carbendazim. And the reproducibility, stability and practicability analysis of real sample have been thoroughly validated simultaneously. Importantly, with the features of fluorescence fingerprint map, the detector could be employed for the distinction of various analytes and further be used for monitoring the nutritional environment within residential and public settings.

Rapid determination of organophosphorus insecticides residue in fruit juice by a fluorescence sensor based on carbon quantum dots

Nitrogen doped carbon quantum dots (N-CQDs) were synthesized by a hydrothermal method. A fluorescence sensor for rapid determination of organophosphorus pesticides residue was developed using the N-CQDs based on acetylcholine enzyme inhibition. Cu2+ effectively quenched the strong fluorescence of N-CQDs, which could be recovered due to the complexation between copper ions and thiocholine, the hydrolysis product of acetylthiocholine catalyzed by acetylcholinesterase. Organophosphorus pesticides inhibited the activity of acetylcholinesterase, resulting in fluorescence quenching of N-CQDs. Fluorescence inhibiting efficiency depends on the concentration of the analytes, and therefore, the sensor could be used for quantitative analysis of organophosphorus pesticides residue. The average recoveries of the analytes ranged from 85.33 % to 110.67 % at the spiked concentrations of 0.015 mg/L, 0.04 mg/L and 0.1 mg/L, and the limits of detection were 2.89 ∼6.40 ng/mL. The developed method had the advantages of simple operation, fast speed, low cost, expensive apparatus-free, and environmental friendliness, which could be used for rapid screening of organophosphorus pesticides residue in real samples.

Ratiometric fluorescent composites united metal-organic frameworks sensing system for detection of methyl-paraoxon

Organophosphorus pesticide residues pose significant risks to human health, but conventional analytical methods are costly and complex. To address this, we developed a new environmentally friendly technique using a simple hydrothermal method to create a ratiometric fluorescent composite (RFC) with two distinct signals: blue and orange. This RFC allowed for rapid detection and quantitative analysis of organophosphorus pesticides. The composite incorporated a cerium-based metal–organic framework (Ce-UiO-66), which could degrade methyl paraoxon (MP) due to the two oxidation states of cerium. The resulting degradation product, p-nitrophenol (p-NP), specifically quenched the blue fluorescence of the RFC via the inner filter effect (IFE), while the orange fluorescence remained unaffected, ensuring consistency under microenvironmental and spectrometer conditions. This innovative approach was sensitive, with a detection limit of 0.55 μM, selective, and repeatable, offering a new strategy for pesticide analysis and safety evaluation of edible and medicinal plant and water samples.

Redox interference-free bimodal paraoxon sensing enabled by an aggregation-induced emission nanozyme catalytically hydrolyzing phosphoesters specifically

In view of the current serious situation of organophosphorus pesticides (OPs) residue contamination, developing rapid and accurate OPs sensors is a matter of urgency. Redox-nanozyme based colorimetric sensors have been widely researched and utilized in OPs residue determination, but overcoming the interference of external redox substances and the effect of single-signal modes on detection performance is still a challenge. Here we fabricated a Zr-based metal–organic framework (MOF) featuring specific phosphatase-like activity and strong aggregation-induced emission (AIE) fluorescence for redox interference-free bimodal pesticide sensing. In the MOF, the activity-tunable Zr4+ node offered high hydrolytic activity and affinity toward P–O containing substrates, and the rigid framework structure effectively enhanced the fluorescence emission of the ligand 1,1,2,2-tetra(4-carboxylphenyl)ethylene. The developed AIEzyme could efficiently catalyze the hydrolysis of paraoxon to yellow p-nitrophenol, which further reduced the intrinsic AIE fluorescence of AIEzyme through internal filtration effect. Thereby, a natural enzyme-free dual-mode colorimetric/fluorescence approach was established for paraoxon detection with no interference from redox substances, and a smartphone-assisted portable platform was further developed to enable the facile, rapid, and high-performance sensing of the pesticide in complex practical matrices.

Novel electrochemiluminescence sensing platform for ultrasensitive detection of malathion residue in tea based on SiO2NSs doped Luminol/AgNPs as a signal amplification strategy

To address the potential hazards of organophosphorus pesticides (OPs) residues in tea, an electrochemiluminescence (ECL) aptasensor based on functionalized nanomaterials was constructed in this work. Firstly, gold nanoparticles (AuNPs) were attached on the surface of multi-walled carbon nanotubes (MWCNTs) by the constant potential electrodeposition to form a compound, and it was utilized to provide excellent immobilization sites for complementary DNA (cDNA). Subsequently, composite nanomaterials were synthesized by a one-pot method with aminated Luminol/silver nanoparticles@silica nanospheres (NH2-Luminol/Ag@SiO2NSs). Finally, NH2-Luminol/Ag@SiO2NSs was combined with a malathion aptamer (Apt) to obtain signal probes (SPs) for the construction of an aptasensor. The aptasensor had a wide linear range (1×10−3-1×103 ng/mL) and a low limit of detection (LOD) (0.3×10−3 ng/mL). It had the virtues of high sensitivity, wonderful stability and excellent specificity, which could be used for the detection of malathion residue in tea. The work provides a proven way for the construction of a rapid and ultrasensitive aptasensor with low-cost.

A novel fluorescent and photothermal probe based on nanozyme-mediated cascade reaction for detecting organophosphorus pesticide residues

In this study, a nanozyme (ZIF-Co-Cys) with high oxidase-like catalytic activity was prepared, and a ratiometric fluorescent/photothermal dual-mode probe was constructed for organophosphorus pesticides (OPs) detection based on the competitive effect of ZIF-Co-Cys and the enzymatic reaction product of acid phosphatase (ACP) on o-phenylenediamine and the inhibition effect of OPs on ACP activity. Using dimethyl dichloroviny phosphate (DDVP) as the model, both the fluorescence intensity ratio and the temperature change of the probe solution exhibited an excellent correlation with OPs concentration. The detection limits were 1.64 ng/mL and 0.084 ng/mL, respectively. Additionally, the detection of DDVP residues in real samples verified the outstanding anti-interference and accuracy of the probe. This work not only provided a complementary dual-mode method for the accurate and rapid detection of OPs residues in complex samples, but also supplied a new insight into the design of a multi-mode sensing platform based on the cascade reaction of nanozyme.

Novel Rhizophus oryzae esterase-immobilized chitosan/carbon nanomaterials as sensing support for enzyme inhibition-based biosensor in the detection of organophosphorus pesticide residues on crops

The use of mobile biosensor would allow for cost-effective and rapid on-site detection of organophosphorus (OP) pesticide. Immobilizing enzyme on electrode would improve the sensitivity of biosensor due to the nature of its specific active site-binding. OP inhibition on esterase enzyme is used as the sensing mechanism of the biosensor. In this study, microbial esterase from Rhizopus oryzae (RoE) was immobilized into modified screen-printed carbon electrode (SPCE) for the fabrication of novel RoE/chitosan/nanomaterial-COOH/SPCE biosensor for the detection of methyl parathion, an OP pesticide. The first phase of this study aims to analyze biochemical characteristics of 1-naphthyl acetate (1-NA) hydrolysis by RoE and enzymatic inhibition of RoE by OP pesticide. RoE kinetic showed the best fit with Langmuir model with the highest linear regression (R2 = 0.996). The inhibition of RoE by OP was shown to be linearly proportional to the enzyme activity (R2 = 0.827). The second phase of this study aims to analyze electrochemical performance of RoE-immobilized biosensor. Various carbon-based sensing support nanomaterials (graphene nanoplatelets (GNP), graphite and multi-walled carbon nanotube (MWCNT)) was functionalised by carboxyl (-COOH) group and screened, where all nanomaterials showed effective sensitivity towards detecting 0.01 ng/L methyl parathion pesticide. GNP-based biosensor exhibited the highest degree of inhibition (9.94 %) and better reproducibility after the first cycle. RoE/chitosan/GNP-COOH/SPCE biosensor is promising to be developed as cost-effective and highly sensitive biosensor for OP pesticide detection.

Near-infrared fluorescent probe for ultrasensitive detection of organophosphorus pesticides and visualization of their interaction with butyrylcholinesterase in living cells

The toxicity of organophosphorus pesticides (OPs) can catastrophically cause liver cell damage and inhibit the catalytic activity of cholinesterase. We designed and synthesized a near-infrared fluorescent probe HP-LZB with large Stokes shift which can specifically identify and detect butyrylcholinesterase (BChE) and visually explore the interaction between OPs and endogenous BChE in living cells. Fluorescence was turned on when HP-LZB was hydrolyzed into HP-LZ in the presence of BChE, and OPs could inhibit BChE's activity resulting in a decrease of fluorescence. Six OPs including three oxon pesticides (paraoxon, chlorpyrifos oxon and diazoxon) and their corresponding thion pesticides (parathion, chlorpyrifos and diazinon) were investigated. Both in vitro and cell experiments indicated that only oxon pesticides could inhibit BChE's activity. The limits of detection (LODs) of paraoxon, chlorpyrifos oxon and diazoxon were as low as 0.295, 0.007 and 0.011 ng mL−1 respectively and the recovery of OPs residue in vegetable samples was satisfactory. Thion pesticides themselves could hardly inhibit the activity of BChE and are only toxic when they are converted to their corresponding oxon form in the metabolic process. However, in this work, thion pesticides were found not be oxidized into their oxon forms in living HepG2 cells due to the lack of cytochrome P450 in hepatoma HepG2 cell lines. Therefore, this probe has great application potential in effectively monitoring OPs in real plant samples and visually exploring the interaction between OPs and BChE in living cells.

A ratiometric fluorescence sensor for detection of organophosphorus pesticides based on enzyme-regulated multifunctional Fe-based metal-organic framework

The residues of organophosphorus pesticides (OPs) are increasing environmental pollution and public health concerns. Thus, the development of simple, convenient and sensitive method for detection of OPs is crucial. Herein, a multifunctional Fe-based MOF with fluorescence, catalytic and adsorption, is synthesized by a simple one-pot hydrothermal method. The ratiometric fluorescence sensor for detection of OPs is constructed by using only one multifunctional sensing material. The NH2-MIL-101(Fe) is able catalyze the o-phenylenediamine (OPD) into 2,3-diaminophenazine (DAP) in the presence of H2O2. The generated DAP can significantly quench the intrinsic fluorescence of NH2-MIL-101(Fe) by the fluorescence resonance energy transfer (FRET) and internal filtration effect (IFE), while producing a new measurable fluorescence. Without immobilization or molecular imprinting, pyrophosphate ion (PPi) can inhibit the peroxidase-like activity of the NH2-MIL-101(Fe) by chelating with Fe3+/Fe2+ redox couple. Moreover, PPi can also be hydrolyzed by alkaline phosphatase (ALP), the presence of OPs inhibits the activity of ALP, resulting in the increase of extra PPi preservation and signal changes of ratiometric fluorescence, the interactions of ALP with different OPs are explored by molecular docking, the OPs (e.g., glyphosate) interact with crucial amino acid residues (Asp, Ser, Ala, Lys and Arg) are indicated. The proposed sensor exhibits excellent detection performance for OPs with the detection limit of 18.7 nM, which provides a promising strategy for detection of OPs.

Nitrogen-doped carbon dots as efficient turn-on fluorescent probe for assay of organophosphorus pesticides

Concerns regarding human health and food safety have generated interest in developing simple, accurate, and cost-effective strategies for evaluating organophosphorus pesticide (OP) residues. In this study, nitrogen-doped carbon dots (N-CDs) were synthesized from a common low-cost precursor via a simple pyrolysis process. The fluorescence of the N-CDs can be suppressed by p-nitrophenol, which is the hydrolysis product of the p-nitrophenyl phosphate salt catalyzed by alkaline phosphatase (ALP). A fluorescent turn-on assay for the inhibitory effect of glyphosate was developed with a low detection limit and wide linear range. Moreover, the feasibility of visualizing OPs in vegetables was demonstrated by the fluorescence imaging of glyphosate on cabbage leaves. This research not only offers a facile method for the synthesis of highly fluorescent CDs but also inspires the development of effective multi-mode sensing platforms that include fluorescent testing and imaging for monitoring pesticide residues.

"On-On-Off" Recyclable Fluorescence Battery for Direct and Selective Detection of Glyphosate and Cu2.

Residues of environmental organophosphorus pesticides (OPs) will seriously endanger human health. Most reported OP sensors utilized the restrictions capacity of OPs on the catalytic capacity of acetylcholinesterase (AChE) to acetylthiocholine chloride (ATCh), which suffers from high costs, weak stability, long reaction time, and unrecyclable. Herein, a recyclable strategy was proposed for selective and sensitive detection of glyphosate (Gly). The weak fluorescence of UIO-66-NH2 at 450 nm was enhanced almost 10-fold after reacting with Gly because of the rotation-restricted emission enhancement mechanism. Moreover, inspired by the process of charging and discharging the batteries, we introduced Cu2+ to chelate with Gly. Because of the strong chelation between Cu2+ and Gly, the Gly was removed from UIO-66-NH2, which resulted in the quenching of fluorescence intensity and making UIO-66-NH2 recycle. This method proposed is fast, recyclable, easily conducted, and with a low 0.33 μM LOD in dd H2O based on 3σ/S. The recovery rates of Gly in tap water ranged from 93.07 to 104.35% within a satisfied 7.75% RSD. The Cu2+ LOD is 0.01 mM based on 3σ/S and 94.37-118.34% recovery rates within 6.48% RSD in tap water. We believe that the findings in this work provide a meaningful and promising strategy to detect Gly and Cu2+ in real samples. This sensor first successfully achieves the recycling use of the material in OP fluorescence detection, which greatly decreases the cost of the designed sensor and reduces the possibility of secondary pollution to the environment, broadens a new circulation dimension of fluorescence detection methods in detecting OPs, and has the potential to remove glyphosate from water. It also provides a method to utilize functionalized metal-organic frameworks to establish various sensors.

Facile synthesis of novel porphyrin-based covalent organic frameworks integrated with Au nanoparticles for highly sensitive detection of organophosphorus pesticide residues

Organophosphorus pesticides (OPs) residues in agricultural products such as vegetables, fruits, and grains pose a threat to food safety and human health. In this work, a novel and highly sensitive electrochemical biosensor was developed for OPs residues detection in real sample, based on the immobilization of acetylcholinesterase (AChE) by electrostatic adsorption on a glassy carbon electrode (GCE) modified with composite nanomaterials of porphyrin-based covalent organic frameworks (p-COFs) loaded by gold nanoparticles (AuNPs) and poly (diallyldimethylammonium chloride) (PDDA). Due to the synergistic effect of p-COFs, AuNPs and PDDA, the fabricated biosensor displayed the remarkable properties with the high electrocataytic activity, and excellent biocompatibility, resulting in a significant signal amplification of as-prepared biosensor. Under optimized conditions, the biosensor showed excellent sensing performances for the detection of methyl parathion (MP), with wide linear ranges from 1.9 × 10−9–3.8 × 10−5 M and a low detection limit as low as 2.3 × 10−10 M, as well as the satisfactory selectivity, excellent reproducibility, anti-interference properties and good stability. It was also successfully applied to the monitoring of MP content in vegetables and fruits, which may be explore a new opportunity for the potential utilization in analysis field.

A molecularly imprinted electrochemical sensor MIP/Cu-MOF/rGO/AuNPs/GCE for highly sensitive detection of electroneutral organophosphorus pesticide residues.

A novel electrochemical sensor, MIP/Cu-MOF/rGO/AuNPs/GCE, was developed by depositing gold nanoparticles, coating Cu-MOF/GO on the surface of glassy carbon electrode (GCE) before electroreducing graphene oxide (GO) to rGO and covering molecularly imprinted membrane by electropolymerization for highly sensitive detection of electroneutral organophosphorus pesticide residues in agricultural product. Cyclic voltammetry, differential pulse voltametry, scanning electron microscopy, energy-dispersive spectroscopy, and atomic force microscopy were used to characterize the imprinted sensor. Several key factors such as chitosan concentration, suspension volume, pH of polymerization solution, and polymerization scanning rate during preparation of the imprinted sensor were optimized in detail. When electroneutral phosmet was used as a template, the linear range of MIP/Cu-MOF/rGO/AuNPs/GCE for detecting phosmet was 1.00 × 10-14-5.00 × 10-7 mol/L with the limit of detection of 7.20 × 10-15 mol/L at working potentials of - 0.2 to 0.6 V. The selectivity, reproducibility, and repeatability of MIP/Cu-MOF/rGO/AuNPs/GCE were all acceptable. The recoveries of this method for determining phosmet in real samples ranged from 94.2 to 106.5%. The MIP/Cu-MOF/rGO/AuNPs/GCE sensor could be applied to detect electroneutral pesticide residues in organisms and agricultural products.

PH-responsive dual-emission carbon dots for the ratiometric detection of organophosphorus pesticides in Brassica chinensis and Hg2+ in water

Accurate and rapid monitoring of organophosphorus pesticides (OPs) residues is crucial for regulating food safety. Herein, dual-emission carbon dots (de-CDs) were fabricated for the ratiometric detection of OPs and Hg2+. The de-CDs exhibited two emission peaks at 678 and 485 nm when excited with visible light. Interestingly, the fluorescence at 678 nm was significantly quenched by Hg2+ mainly because of the static quenching effect, whereas that at 485 nm exhibited a slight change. More significantly, the quenched fluorescence of the de-CDs recovered remarkably after introducing omethoate, diazinon and malathion. Accordingly, the ratiometric detection of the three OPs and Hg2+ was achieved with high selectivity and robust performance. In addition, the OPs residues assay in Brassica chinensis was successfully performed with satisfactory results. This study not only provides an attractive tool for the simple and rapid assay of OPs but also offers new insights into the fabrication of multi-functional carbon dots.

CdTe@ZnS quantum dots for rapid detection of organophosphorus pesticide in agricultural products

Organophosphorus pesticides (OPPs) constitute the most widely employed class of pesticides. However, the prevalent use of OPPs, while advantageous, raises concerns due to their toxicity, posing serious threats to food safety. Chemical sensors utilizing quantum dots (QDs) demonstrate promising applications in rapidly detecting OPPs residues, thereby facilitating efficient inspection of agricultural products. In this study, we employ an aqueous synthesis approach to prepare low toxic CdTe@ZnS QDs with stable fluorescence properties. To mitigate the risk of imprecise measurements stemming from the inherent susceptibility of fluorescence to quenching, we have adopted the principle of fluorescence resonance energy transfer (FRET) for the construction of the turn-on quantum dot sensor. With a detection limit for chlorpyrifos as low as 10 ppb (10 μg/L), the QDs sensor exhibits notable resistance to interference from various pesticides. Application of this system to detect organophosphorothioate pesticides in apples produced results consistent with those obtained from high-performance liquid chromatography (HPLC) detection, affirming the promising application prospects of this sensing system for the rapid detection of OPPs residues.

Determination of Concentrations of Pesticide Residues in Chevon obtained from Abattoir of Jimeta, Adamawa State, Nigeria

The current work was aimed at determining levels of Organochlorine (OCP) and Organophosphorus pesticide (OPP) residues in goats obtained from the study area. This was to enable the public aware of the presence of hazardous pesticides residues in the food chain. Forty samples were collected from; Chevon, intestines, kidneys and livers of ten sampled goats. The sampled goats were represented by G1 = first goat, G2 = second goat, G3 = third goat, G4 = fourth goat, G5 = fifth goat, G6 = sixth goat, G7 = seventh goat, G8 = eighth goat, G9 = ninth goat and G10 = tenth goat. Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) was used in preparing the samples. Analysis was done with Gas chromatography – Mass spectrometer (GC/MS) Acqmethod pesticide. Results showed that OCP residues were not detected in all the samples. Anthracene, dichlorpyrifos, diazinon, dimethoate, primifos-methyl, and malathion were detected below the threshold value of 0.001 mg/Kg. Likewise, all pesticide residues in G7 and G9 samples were below the threshold limit (0.001) mg/Kg. Dichlorvos wasdetected in chevon of G1, G3 and G4 with range from 0.043 mg/Kg in G4 – 0.113 mg/Kg in G1. Chlorpyrifos was detected in intestine of G1, G2, G3, G4, G6, G8 and G10. The highest was 0.051 mg/Kg in G4 and lowest was 0.013 mg/Kg in G10. Kidney samples of GI, G2, G3 and G4 contained chlorpyrifos ranging from 0.011 mg/Kg in G8 – 0053 mg/Kg in G4. dichlovos was detected in kidney samples of G1, G2, G3, G4 and G8. Highest concentration of dichlovos in the kidney was; 0.069 00014 mg/Kg in G1 while the lowest was in G8 (0.011mg/Kg). Liver samples of G2, G4, G6 and G10 contained chlopyrifos ranging from 0,007 mg/Kg in G10 – 0.050 mg/Kg in G4. dichlovos was present in livers of G2, G4 and G6. Highest was in G4 (0.037 mg/Kg) and lowest value was in G6 (0.021 mg/Kg). Apart from in Kidney of G8, concentrations of chlorpyrifos in all the samples were above the maximum residue level (MRL) values of 0.01 mg/Kg. Consumption of which may pose health problem. Concentration of dichlorvos detected in the samples were below the MRL of 1.00mg/Kg, this may not pose immediate health issues but continuous intake may bring about accumulative health risk issues. Keywords: Chevon, chlorpyrifos, dimethoate, organophosphorus, malathion, dichlorvos, health, risk

A tailored dual core-shell magnetic SERS substrate with precise shell-thickness control for trace organophosphorus pesticides residues detection

For addressing the challenges of strong affinity SERS substrate to organophosphorus pesticides (OPs), herein, a rapid water-assisted layer-by-layer heteronuclear growth method was investigated to grow uniform UiO-66 shell with controllable thickness outside the magnetic core and provide abundant defect sites for OPs adsorption. By further assembling the tailored Au@Ag, a highly sensitive SERS substrate Fe3O4-COOH@UiO-66/Au@Ag (FCUAA) was synthesized with a SERS enhancement factor of 2.11 × 107. The substrate's suitability for the actual vegetable samples (cowpeas and peppers) was confirmed under both destructive and non-destructive detection conditions, showing a strong SERS response to fenthion and triazophos, with limits of detection of 1.21 × 10-5 and 2.96 × 10-3 mg/kg in the vegetables under destructive conditions, and 0.13 and 1.39 ng/cm2 for non-destructive detection, respectively. The FCUAA substrate had high SERS performance, effective adsorption capability for OPs, and demonstrated good applicability, thus exhibiting great potential for rapid detection of trace OPs residues in the food industry.

Expression of Concern: Risk assessment of organophosphorus pesticide residues in drinking water resources: Statistical and Monte-Carlo approach

Expression of Concern: Risk assessment of organophosphorus pesticide residues in drinking water resources: Statistical and Monte-Carlo approach

Organochlorine, organophosphorus, and carbamate pesticide residues in an Ethiopian Rift Valley Lake Hawassa: occurrences and possible ecological risks.

Currently, pesticide production and use are on the rise globally. This trend is certain to continue in the coming decades with residues posing risks to the environment and human health even at low levels. Although various aspects of pesticides and their possible implications have widely been studied, such studies have mostly been carried out in developed countries leaving the rest of the world with little scientific information. We present here the results of a study on the occurrences, concentrations, and ecological risks of 30 pesticide residues (PRs) in water and sediment samples from a tropical freshwater Lake Hawassa in the Ethiopian Rift Valley. A total of 54 composite samples of water and sediment were collected from three sampling sites on three occasions. The samples were prepared by quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique, and analyzed using GC-MS at Bless Agri Food Laboratory Service located in Addis Ababa, Ethiopia. The study applied the risk quotient (RQ) method to scrutinize the risks posed to aquatic biota by the detected PRs. The results showed occurrences of 18 and 20 PRs in the water and sediment samples, respectively. The majority, 78 and 75% of the detected PRs in water and sediment samples, respectively represent the organochlorine chemical class. Concentrations of heptachlor epoxide were significantly (p ≤ 0.001) higher than those of the remaining pesticides in both matrices. Of the pesticides detected, 77% were present in water and 83% in sediment samples and pose a serious risk (RQ ≥ 1) to the Lake Hawassa biota. This calls for further research to investigate the risks to human health posed by the PRs. The findings of this study can contribute to the development of global protocols, as they support the concerns raised about the ecological and public health impacts of PRs on a global level.