Antioxidant enzyme activities, molecular docking studies, MM-GBSA, and molecular dynamic of chlorpyrifos in freshwater fish Capoeta umbla

Chlorpyrifos (CPF), which was started to be used in 1965, is a broad spectrum organophosphate insecticide that is used more and more day by day. Commonly used to control pests in farmland and homes, CPF is more toxic to fish than organochlorine compounds. CPF poses a serious threat to the health of humans and aquatic organisms. This paper studies the relationship between CPF exposure and antioxidant enzyme activities in gill, kidney and liver tissues of Capoeta umbla. Different time intervals (12, 24, 48, 72, and 96 h) and CPF doses (55 and 110 µg L-1) were used in the study. Spectrophotometrical measures were taken in all tissues for antioxidant enzyme activities and malondialdehyde (MDA) levels, as indices of the lipid peroxidation (LPO). A positive relationship between CPF and MDA levels was found in the study at a statistically significant level (p < 0.05). The study also found a negative relationship between CPF levels and catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) activity. Independent variables in the study can act as biomarkers of CPF exposure. The study recommends employing proper ecotoxicological risk evaluations in cases of CPF usage as a pesticide. The activities of the studied molecules against various proteins that are crystal structure of human peroxiredoxin 5 (PDB ID: 1HD2) has docking score value is -2.67, crystal structure of Bovine Xanthine Oxidase (PDB ID: 3NRZ) has docking score value is -3.76, and crystal structure of antibacterial FabH (PDB ID: 4Z8D) has docking score value is -3.16, were compared. Molecular dynamic (MD) calculations were made in 100 ns. MM/GBSA methods are calculated binding free energy. Afterwards, ADME/T analysis was performed to examine the some properties of the molecules.Communicated by Ramaswamy H. Sarma.

Occurrence of chlorpyrifos and organochlorine pesticides in a native bumblebee (Bombus pauloensis) living under different land uses in the southeastern Pampas, Argentina

Pollinators such as Apidae bees are vital for ecosystems and food security. Unfortunately, their populations have declined due to several factors including pesticide use. Among them, the organophosphate insecticide chlorpyrifos, poses a global threat, while legacy compounds like organochlorine pesticides (OCPs) easily bioaccumulate, increasing the concern. Bombus pauloensis, a widely distributed native bee in Argentina, is used for commercial pollination; however, information regarding their health status is scarce. This study assessed chlorpyrifos and OCP levels in B. pauloensis (workers and males) and related environmental matrices living from three different land uses schemes, by means of GC-ECD and GC-MS. The ornamental horticulture field (OP) showed the highest total pesticide concentrations in workers (13.1 ng/g), flowers and soils, whereas the organic agriculture field (OA) exhibited the lowest. Chlorpyrifos was the most abundant compound, accounting for at least 20 % of pesticide load across all matrices. The food production horticulture field (FH) had the highest chlorpyrifos concentration in workers, males and soils (5.0, 4.4 and 3.3 ng/g, respectively), suggesting a local greater usage, whereas OA showed the lowest. Regarding OCPs groups, Drins and DDTs were predominant in most matrices, with FH males registering the highest levels (4.0 and 2.5 ng/g, respectively), closely followed by OP. However, metabolites' contribution indicated historical use and atmospheric inputs in all sites. Multivariate analyses confirmed the significance of site and bumblebee sex to explain pesticide composition. Males from all sites exhibited higher chlorpyrifos levels than workers and this trend was similar for some OCP groups. Overall, OA differed from FH and OP, indicating a correlation between production modes and pesticide profiles. This study demonstrates the value of B. pauloensis as a pesticide biomonitor but also offers insights into its populations' health in the area. In this sense, this information could be useful towards the preservation of this crucial pollinator.

Biodegradation mechanism of chlorpyrifos by Bacillus sp. H27: Degradation enzymes, products, pathways and whole genome sequencing analysis

Chlorpyrifos (CP) is a pesticide widely used in agricultural production. However, excessive use of CP is risky for human health and the ecological environment. Microbial remediation has become a research hotspot of environmental pollution control. In this study, the effective CP-degrading strain H27 (Bacillus cereus) was screened from farmland soil, and the degradation ratio was more than 80%. Then, the degradation mechanism was discussed in terms of enzymes, pathways, products and genes, and the mechanism was improved in terms of cell motility, secretory transport system and biofilm formation. The key CP-degrading enzymes were mainly intracellular enzymes (IE), and the degradation ratio reached 49.6% within 30 min. The optimal pH for IE was 7.0, and the optimal temperature was 25 °C. Using DFT and HPLC‒MS analysis, it was found that degradation mainly involved oxidation, hydrolysis and other reactions, and 3 degradation pathways and 14 products were identified, among which TCP (3,5,6-trichloro-2-pyridinol) was the main primary degradation product in addition to small molecules such as CO2 and H2O. Finally, the whole genome of strain H27 was sequenced, and the related degrading genes and enzymes were investigated to improve the metabolic pathways. Strain H27 had perfect genes related to flagellar assembly and chemotaxis and tended to tolerate CP. Moreover, it can secrete esterase, phosphatase and other substances, which can form biofilms and degrade CP in the environment. In addition, CP enters the cell under the action of permeases or transporters, and it is metabolized by IE. The degradation mechanism of CP by strain H27 is speculated in this study, which provided a theoretical basis for enriching CP-degrading bacteria resources, improving degradation metabolic pathways and mechanisms, and applying strain H27 to environmental pollution remediation.

Photocatalytic degradation of chlorpyrifos using Ag nanoparticles-doped g-C3N5 decorated with dendritic CdS

In this work, g-C3N5/CdS dendrite/AgNPs nanocomposite was synthesized using a mixed method consisting of hydrothermal, ultrasonic and chemistry reduction with sodium borohydride. The characterization of the as-prepared nanocomposite was done using infrared spectroscopy, X-ray, scanning electron microscopy, transmission electron microscopy, BET, and DRS methods was performed. The DRS results showed that the g-C3N5/CdS dendrite/AgNPs nanocomposite nanocomposite has a band gap of 1.08 eV. This band gap indicates the good capability of this nanocomposite as a photocatalyst. Accordingly, the photocatalytic degradation of chlorpyrifos (CPS) in was performed in an aqueous solution of the synthesized nanocomposite. The results showed that almost 95.3% of this poison, a concentration of 50 mg L-1 was degraded in the presence of 0.05 g L-1 of nanocomposite at pH = 5 in a 60 min. Hydroxide radicals and holes play a significant role in the photocatalytic process. The reusability of the nanocomposite with excellent performance in the degradation of photocatalytic toxins caused by the reduction in the electron-hole recombination and the high surface area of the nanocomposite are among the unique features of this work.

Dispersive liquid‒liquid microextraction combined with enzyme-linked immunosorbent assay for the analysis of chlorpyrifos in cereal samples

In this paper, an analysis method for chlorpyrifos (CPF) in cereal samples was proposed using dispersive liquid‒liquid microextraction combined with an enzyme-linked immunosorbent assay. In the dispersive liquid‒liquid microextraction, deep eutectic solvents and fatty acids were used as solvents to extract, purify, and concentrate CPF in cereals. In the enzyme-linked immunosorbent assay, gold nanoparticles were utilized to enrich and conjugate more antibodies and horseradish peroxidase, while magnetic beads were used as solid supports to amplify the signal and shorten the detection time of CPF. The linearity range was 0.002-1 μg kg-1, and the limit of detection was 0.0006 μg kg-1. The extraction recoveries were 86.7-99.9% with a relative standard deviation of less than 7.0%. The proposed method was successfully used to analyze CPF in cereal samples (rice, wheat, maize, and millet) and has prospects for the pretreatment and detection of CPF residues in other food samples.

Application of biological early warning systems in wastewater treatment plants: Introducing a promising approach to monitor changing wastewater composition

Wastewater treatment plants (WWTPs) are a major source of micropollutants to surface waters. Currently, their chemical or biological monitoring is realized by using grab or composite samples, which provides only snapshots of the current wastewater composition. Especially in WWTPs with industrial input, the wastewater composition can be highly variable and a continuous assessment would be advantageous, but very labor and cost intensive. A promising concept are automated real-time biological early warning systems (BEWS), where living organisms are constantly exposed to the water and an alarm is triggered if the organism's responses exceed a harmful threshold of acute toxicity. Currently, BEWS are established for drinking water and surface water but are seldom applied to monitor wastewater. This study demonstrates that a battery of BEWS using algae (Chlorella vulgaris in the Algae Toximeter, bbe Moldaenke), water flea (Daphnia magna in the DaphTox II, bbe Moldaenke) and gammarids (Gammarus pulex in the Sensaguard, REMONDIS Aqua) can be adapted for wastewater surveillance. For continuous low-maintenance operation, a back-washable membrane filtration system is indispensable for adequate preparation of treated wastewater. Only minor deviations in the reaction of the organisms towards treated and filtered wastewater compared to surface waters were detected. After spiking treated wastewater with two concentrations of the model compounds diuron, chlorpyrifos methyl, and sertraline, the organisms in the different BEWS showed clear responses depending on the respective compound, concentration and mode of action. Immediate effects on photosynthetic activity of algae were detected for diuron exposure, and strong behavioral changes in water flea and gammarids after exposure to chlorpyrifos methyl or sertraline were observed, which triggered automated alarms. Different types of data analysis were applied to extract more information out of the specific behavioral traits, than only provided by the vendors algorithms. To investigate, whether behavioral movement changes can be linked to impact other endpoints, the effects on feeding activity of G. pulex were evaluated and results indicated significant differences between the exposures. Overall, these findings provide an important basis indicating that BEWS have the potential to act as alarm systems for pollution events in the wastewater sector.

T4PPVB-COP composite-driven innovative electrochemiluminescence aptasensor for ultra-sensitive detection of chlorpyrifos

Herein, an enhanced electrochemiluminescence (ECL) aptasensor driven by a complex (T4PPVB-COP@CdS QDs) with large specific surface area and high stability was constructed for highly sensitive detection of chlorpyrifos (CPF), using electrostatic interactions and signal amplification techniques. In the presence of CPF, the specific binding between the aptamer and CPF caused partial detachment of the aptamer from the sensor, thus restoring the ECL signal. Notably, gold nanoparticles functionalized with streptavidin (SA) as signal enhancers further amplified the ECL signal in specific interactions with aptamers, thereby improving the sensitivity of the assay. Based on this, the proposed ECL aptasensor demonstrated significant detection performance for CPF with a linear range of 1-107 pg/mL and a LOD of 0.34 pg/mL. Furthermore, the feasibility of the ECL aptasensor was validated by the detection and analysis of CPF in real samples, which also provided a broad reference value for bioanalysis.

Exorbitant signatures of pesticides and pharmaceuticals in municipal solid wastes (MSWs): Novel insights through risk analysis, dissolution dynamics, and model-based source identification

Studies on the occurrence and fates of emerging organic micropollutants (EOMPs) like pharmaceuticals and pesticides in MSWs are scarce in the literature. Therefore, MSWs were sampled from 20 Indian landfills and characterized for five widely consumed EOMPs (chlorpyrifos, cypermethrin, carbofuran, carbamazepine, and sodium diclofenac), physicochemical, and biological properties. The pesticide (median: 0.17-0.44 mg kg-1) and pharmaceutical (median: 0.20-0.26 mg kg-1) concentrations significantly fluctuated based on landfill localities. Eventually, principal component and multi-factor (MFA) models demonstrated close interactions of EOMPs with biological (microbial biomass and humification rates) and chemical (N, P, K, Ca, S, etc.) properties of MSWs. At the same time, the MFA resolved that EOMPs' fates in MSWs significantly differ from bigger cosmopolitan cities to smaller rural townships. Correspondingly, the concentration-driven ecological risks were high in 15 MSWs with EOMP-toxicity ranks of diclofenac > carbofuran = chlorpyrifos > cypermethrin > carbamazepine. The EOMPs' dissolution dynamics and source apportionments were evaluated using the positive matrix factorization (PMF) model for the first time on experimental data, extracting four anthropogenic sources (households, heterogeneous business centers, agricultural, and open drains). The most significant contribution of EOMPs to MSWs was due to heterogeneous business activity. Notably, the aging of soluble chemical fractions seems to influence the source characteristics of EOMPs strongly.

Rapid detection of residual chlorpyrifos and pyrimethanil on fruit surface by surface-enhanced Raman spectroscopy integrated with deep learning approach

Chlorpyrifos and pyrimethanil are widely used insecticides/fungicides in agriculture. The residual pesticides/fungicides remaining in fruits and vegetables may do harm to human health if they are taken without notice by the customers. Therefore, it is important to develop methods and tools for the rapid detection of pesticides/fungicides in fruits and vegetables, which are highly demanded in the current markets. Surface-enhanced Raman spectroscopy (SERS) can achieve trace chemical detection, while it is still a challenge to apply SERS for the detection and identification of mixed pesticides/fungicides. In this work, we tried to combine SERS technique and deep learning spectral analysis for the determination of mixed chlorpyrifos and pyrimethanil on the surface of fruits including apples and strawberries. Especially, the multi-channel convolutional neural networks-gate recurrent unit (MC-CNN-GRU) classification model was used to extract sequence and spatial information in the spectra, so that the accuracy of the optimized classification model could reach 99% even when the mixture ratio of pesticide/fungicide varied considerably. This work therefore demonstrates an effective application of using SERS combined deep learning approach in the rapid detection and identification of different mixed pesticides in agricultural products.

Remediation of pesticides contaminated water using biowastes-derived carbon rich biochar

The competition impact and feedstock type on the removal of water pesticides using biochar have not yet been sufficiently investigated. Therefore, here we investigated the potentiality of three different biochars (BCs) derived from rice husk (RHB), date pit (DPB), and sugarcane bagasse (SBB) biowastes for the simultaneous removal of ten pesticides from water in a competitive adsorption system. The BCs structural characterization and morphology were investigated by XRD, FTIR spectroscopy and SEM analysis. The potential adsorption mechanisms have been investigated using various isothermal and kinetic models. RHB showed the highest removal percentages (61% for atrazine/dimethoate and 97.6% for diuron/chlorfenvinphos) followed by DPB (56% for atrazine/dimethoate and 95.4% for diuron/chlorpyrifos) and then SBB (60.8% for atrazine/dimethoate and 90.8% for chlorpyrifos/malathion). The higher adsorption capacity of RHB and DPB than SBB can be due to their high total pore volume and specific surface area (SSA). Langmuir model described well the sorption data (R2 = 0.99). Adsorption equilibrium was achieved after 60 min for RHB, and 120 min for both DPB and SBB. The optimum adsorbent dose (g/L) was 10 for RHB and 4 for DPB and SBB. The removal efficiency of pesticides was enhanced by decreasing pH from 9 to 5 by RHB and to 3 by DPB and SBB. XRD and FTIR spectroscopy confirmed that BCs contain some active adsorption groups and metal oxides such as MgO, SiO, Al2O3, CaO, and TiO2 that can play an effective role in the pesticides sorption. BET-N2 adsorption analysis demonstrated that the BC pore size contributes significantly to pesticide adsorption. These findings indicate that RHB, DPB, and SBB have ability for adsorption of water pesticides even under acidic conditions. Therefore, the rice husk, date pit, and sugarcane bagasse biowastes could be pyrolyzed and reused as effective and low-cost sorbents for elimination of hazardous substances such as pesticides in the aqueous environments.

Water quality, human health risk, and pesticides accumulation in African catfish and Nile tilapia from the Kitchener Drain-Egypt

Pesticides are toxic and could negatively impact humans and the ecosystem. The Kitchener Drain is among the longest drains in Egypt and carries a wide range of wastewater from the agriculture sector, which contains pesticides and may pollute the ecosystem. Thus, water quality, human health risk, and pesticide accumulation in African catfish and Nile tilapia from the Kitchener Drain-Egypt. The water and fish samples were collected from Kitchener Drain in Kafr Elsheikh Governorate, Egypt, during the four seasons. The results indicated that heptachlor and diazinon were undetected during the four seasons. However, endosulfan, chlorpyrifos, and dicofol were detected in winter and autumn. Only p,p'-DDT was detected during spring. Endosulfan, heptachlor, and aldrin were detected in Nile tilapia during winter. Only heptachlor and aldrin were detected during spring. Endosulfan, heptachlor, dicofol, p,p'-DDT, chlorpyrifos, and diazinon were detected in the autumn season. In summer, dicofol and p,p'-DDT were detected, while endosulfan, heptachlor p,p'-DDT, aldrin, chlorpyrifos, and diazinon were not detected. In African catfish, endosulfan, heptachlor, dicofol, and p,p'-DDT were detected during winter, while chlorpyrifos, aldrin, and chlorpyrifos, aldrin, and diazinon were not detected. In the spring season, endosulfan, heptachlor, and aldrin were detected. Endosulfan, heptachlor, dicofol, p,p'-DDT, aldrin, chlorpyrifos, and diazinon were detected in the autumn season. Similarly, in the summer season, endosulfan, heptachlor, dicofol, p,p'-DDT, aldrin, chlorpyrifos, and diazinon were detected. The sequence of estimated daily intake (EDI) in Nile tilapia during the four seasons is heptachlor > endosulfan > dicofol > p,p'-DDT > aldrin > diazinon > chlorpyrifos. The sequence of EDI in African catfish during the four seasons is endosulfan > p,p'-DDT > heptachlor > aldrin > dicofol > diazinon > chlorpyrifos. In conclusion, the results confirmed the absence of a hazard index for consuming Nile tilapia and African catfish collected from the Kitchener drain.

Fluorescent nanostructured carbon dot-aptasensor for chlorpyrifos detection: Elucidating the interaction mechanism for an environmentally hazardous pollutant

Chlorpyrifos (CPF) is a commonly used insecticide found in many water sources and is related to several health and environmental effects. Biosensors based on aptamers (single-stranded nucleic acid oligonucleotides) are promising alternatives to achieve the detection of CPF and other pesticides in natural waters. However, several challenges need to be addressed to promote the real application of functional aptasensing devices. In this work, an ssDNA aptamer (S1) is combined with carbon quantum dots (CD) and graphene oxide (GO) to produce a stable fluorescent aptasensor characterized through spectrophotometric and electrophoretic techniques. For a deeper understanding of the system, the mechanism of molecular interaction was studied through docking modeling using free bioinformatic tools like HDOCK, showing that the stem-loops and the higher guanine (G) content are crucial for better interaction. The model also suggests the possibility of generating a truncated aptamer to improve the binding affinity. The biosensor was evaluated for CPF detection, showing a low LOD of 0.01 μg L-1 and good specificity in tap water, even compared to other organophosphates pesticides (OPs) like profenofos. Finally, the recovery of the proposed aptasensor was evaluated in some natural water using spiked samples and compared with UPLC MS-MS chromatography as the gold standard, showing a good recovery above 2.85 nM and evidencing the need of protecting ssDNA aptamers from an erratic interaction with the aromatic groups of dissolved organic matter (humic substances). This work paves the way for a better aptasensors design and the on-site implementation of novel devices for environmental monitoring.

Characterization and fitness cost of bifenthrin resistance in Rhopalosiphum padi (Hemiptera: Aphididae)

Rhopalosiphum padi is an important global wheat pest. The pyrethroid insecticide bifenthrin is widely used in the control R. padi. We explored the resistance potential, cross-resistance, adaptive costs, and resistance mechanism of R. padi to bifenthrin using a bifenthrin-resistant strain (Rp-BIF) established in laboratory. The Rp-BIF strain developed extremely high resistance against bifenthrin (1033.036-fold). Cross-resistance analyses showed that the Rp-BIF strain had an extremely high level of cross-resistance to deltamethrin (974.483-fold), moderate levels of cross-resistance to chlorfenapyr (34.051-fold), isoprocarb (27.415-fold), imidacloprid (14.819-fold), and thiamethoxam (11.228-fold), whereas negative cross-resistance was observed to chlorpyrifos (0.379-fold). The enzymatic activity results suggested that P450 played an important role in bifenthrin resistance. A super-kdr mutation (M918L) of voltage-gated sodium channel (VGSC) was found in the bifenthrin-resistant individuals. When compared with the susceptible strain (Rp-SS), the Rp-BIF strain was significantly inferior in multiple life table parameters, exhibiting a relative fitness of 0.69. Our toxicological and biochemical studies indicated that multiple mechanisms of resistance might be involved in the resistance trait. Our results provide insight into the bifenthrin resistance of R. padi and can contribute to improve management of bifenthrin-resistant R. padi in the field.

Portable Sensor Array for On-Site Detection and Discrimination of Pesticides and Herbicides Using Multivariate Analysis

Modern agricultural practice relies heavily on pesticides and herbicides to increase crop productivity, and consequently, their residues have a negative impact on the environment and public health. Thus, keeping these issues in account, herein we developed an azodye-based chromogenic sensor array for the detection and discrimination of pesticides and herbicides in food and soil samples, utilizing machine learning approaches such as hierarchical clustering analysis, principal component analysis, linear discriminant analysis (LDA), and partial least square regression (PLSR). The azodye-based sensor array was developed in combination with various metal ions owing to their different photophysical properties, which led to distinct patterns toward various pesticides and herbicides. The obtained distinct patterns were recognized and processed through automated multivariate analysis, which enables the selective and sensitive identification and discrimination of various target analytes. Further, the qualitative and quantitative determination of target analytes were performed using LDA and PLSR; the results obtained show a linear correlation with varied concentrations of target analytes with R2 values from 0.89 to 0.96, the limit of detection from 5.3 to 11.8 ppm with a linear working range from 1 to 30 μM toward analytes under investigation. Further, the developed sensor array was successfully utilized for the discrimination of a binary mixture of pesticide (chlorpyrifos) and herbicide (glyphosate).

A highly selective self-powered sensor based on the upconversion nanoparticles/CdS nanospheres for chlorpyrifos detection

Light sources are crucial for photoelectrochemical (PEC) self-powered sensing, where visible light is widely used. However, due to its high energy, it has some downsides as an irradiation source for overall system, so it is urgent to achieve effective near-infrared (NIR) light absorption because it makes up a significant portion of the solar spectrum. Herein, up-conversion nanoparticles (UCNPs) that could increase the energy of low-energy radiation were combined with semiconductor CdS as the photoactive material (UCNPs/CdS), which broadens the response range of solar spectrum. The NIR light-excited self-powered sensor could be produced via oxidizing H2O at photoanode and lowering dissolved oxygen at cathode under the NIR light without external voltage. Meanwhile, molecularly imprinted polymer (MIP) was added to photoanode as a recognition element to increase the sensor's selectivity. The open-circuit voltage of the self-powered sensor grew linearly as chlorpyrifos concentration climbed from 0.01 to 100 ng mL-1, showing good selectivity as well as reproducibility. This work provides valuable basis for the preparation of efficient and practical PEC sensor with NIR light response.

Effects of intensive agriculture and urbanization on water quality and pesticide risks in freshwater ecosystems of the Ecuadorian Amazon

The Ecuadorian Amazon has experienced a significant land use change due to the demographic increase and the expansion of the agricultural frontier. Such changes in land use have been associated to water pollution problems, including the emission of untreated urban wastewater and pesticides. Here we provide the first report on the influence of urbanization and intensive agriculture expansion on water quality parameters, pesticide contamination and the ecological status of Amazonian freshwater ecosystems of Ecuador. We monitored 19 water quality parameters, 27 pesticides, and the macroinvertebrate community in 40 sampling locations of the Napo River basin (northern Ecuador), including a nature conservation reserve and sites in areas influenced by African palm oil production, corn production and urbanization. The ecological risks of pesticides were assessed using a probabilistic approach based on species sensitivity distributions. The results of our study show that urban areas and areas dominated by African palm oil production have a significant influence on water quality parameters, affecting macroinvertebrate communities and biomonitoring indices. Pesticide residues were detected in all sampling sites, with carbendazim, azoxystrobin, diazinon, propiconazole and imidacloprid showing the largest prevalence (>80% of the samples). We found a significant effect of land use on water pesticide contamination, with residues of organophosphate insecticides correlating with African palm oil production and some fungicides with urban areas. The pesticide risk assessment indicated organophosphate insecticides (ethion, chlorpyrifos, azinphos-methyl, profenofos and prothiophos) and imidacloprid as the compounds posing the largest ecotoxicological hazard, with pesticide mixtures potentially affecting up to 26-29% of aquatic species. Ecological risks of organophosphate insecticides were more likely to occur in rivers surrounded by African palm oil plantations, while imidacloprid risks were identified in corn crop areas as well as in natural areas. Future investigations are needed to clarify the sources of imidacloprid contamination and to assess its effects for Amazonian freshwater ecosystems.

The Dissipation Behavior and Risk Assessment of Carbendazim Under Individual and Joint Applications on Peach (Amygdalus persica L.)

Dissipation, residue levels, and ingestion risks of carbendazim in peach (Amygdalus persica L.) were investigated with individual and joint applications in the present study. The dissipation kinetics of carbendazim, chlorpyrifos, prochloraz, and imidacloprid were evaluated by the first-order kinetics. When carbendazim was individually applied, the final residual concentration was 2.97 mg kg-1 and the half-life was 17.4 d. In the joint application of carbendazim with chlorpyrifos, prochloraz, and imidacloprid, the residual concentrations at 35 d after spraying were 7.16, 7.50, and 4.26 mg kg-1 and the half-lives were 30.8, 23.7, and 23.2 d, respectively, which showed an increase of 1.3-1.8 times compared with the single application of carbendazim. In addition, the effects of household processing of rinsing and peeling were investigated, and a high removal rate of 54.6% and 76.5% were found. Furthermore, the carbendazim ingestion risk assessment was conducted, which indicated that the acute health risk (aHI) and hazard quotient (HQ) of carbendazim were all within acceptable levels ranging from 21.7% to 40.9%. However, a higher ingestion risk of carbendazim was found under the joint application. This study provides some preliminary guidance for the joint application and risk assessment of carbendazim in peach, which is worth further investigation.

Toxicity analysis of endocrine disrupting pesticides on non-target organisms: A critical analysis on toxicity mechanisms

Endocrine disrupting compounds are the chemicals which mimics the natural endocrine hormones and bind to the receptors made for the hormones. Upon binding they activate the cascade of reaction which leads to permanent activating of the signalling cycle and ultimately leads to uncontrolled growth. Pesticides are one of the endocrine disrupting chemicals which cause cancer, congenital birth defects, and reproductive defects in non-target organisms. Non-target organisms are keen on exposing to these pesticides. Although several studies have reported about the pesticide toxicity. But a critical analysis of pesticide toxicity and its role as endocrine disruptor is lacking. Therefore, the presented review literature is an endeavour to understand the role of the pesticides as endocrine disruptors. In addition, it discusses about the endocrine disruption, neurological disruption, genotoxicity, and ROS induced pesticide toxicity. Moreover, biochemical mechanisms of pesticide toxicity on non-target organisms have been presented. An insight on the chlorpyrifos toxicity on non-target organisms along with species names have been presented.

Seasonal variation in pesticide residue occurrences in surface waters found in Narok and Bomet Counties, Kenya

Narok and Bomet are agricultural counties in Kenya which depend on flowing surface waters for farming activities. Agrochemicals have frequently been used to increase agricultural produce in this region. Occasionally, appropriate pesticide utilization measures are not followed. These surface waters are also consumed domestically by humans, livestock, and wild animals thus posing safety concerns to them. The current study sought to evaluate the levels and nature of pesticide residues found in surface waters in the dry and wet seasons of these counties. Eight water samples were collected in July (dry season) and October (wet season) at four different river sites in each of the two counties predetermined by the agricultural activity of its proximate environs. Pesticides extracted by solid phase extraction were analyzed by gas chromatography-mass spectrometry. At least 38 different pesticides were detected in the two counties with the highest concentration being recorded for chlorpyrifos and piperidine in Narok and Bomet counties, respectively. The pesticides chlorpyrifos, cypermethrin, cyfluthrin, and cyhalothrin were more prevalent in Narok County while triazine, semicarbazone, and epinephrine were more prevalent in Bomet County. There were significantly more pesticides detected during the wet season (P ≤ 0.05). Out of the nine prevalent pesticides detected, four of them posed serious ecotoxicology concerns with risk quotients above 1.0 (high risk); thus, there is a need for more government policy interventions in deterring farming near riparian lands and in training of famers regarding best practice for pesticide applications.

Facile adsorption of organophosphate pesticides over HKUST-1 MOFs

The recovery of organophosphate pesticides (OPPs) from aqueous solutions is imperative considering their agricultural and environmental implications. Among various mitigation approaches used for OPPs' removal, adsorption offers many advantageous features for OPPs abatement owing to its benign nature, cost-effective processing, and non-requirement of excessive equipment. This research describes the adsorptive removal of three organophosphate pesticides (OPPs) namely chlorpyrifos (CPF), methyl parathion (MP), and malathion (MAL) by HKUST-1 (HKUST = Hong Kong University of Science and Technology) metal-organic framework (MOF). The synthesis of HKUST-1 MOFs was confirmed by various spectroscopic and microscopic techniques. The adsorption kinetics was systematically investigated by varying three parameters to include solution pH, contact time, and initial pesticide concentration. Among all the three pesticides, HKUST-1 showed enhanced removal of CPF in terms of pH, resulting in an adsorption capacity of 1.82 mg·g-1. However, under the effect of contact time at 60 min, the adsorption capacity of HKUST-1 for PM, MAL, and CPF were computed to be 1.83, 1.79, and 0.44 mg·g-1, respectively. Besides, HKUST-1 showed a remarkable performance towards adsorptive removal of MAL (14.01 mg·g-1 at 10 mg·L-1 concentration) with linear increase in adsorption capacity as the function of initial pesticide concentration. The MOFs were also able to retain ca. 50% of their adsorption efficiency over the course of five cycles of adsorptive removal of CP. In the future, a comprehensive data table showing the performance of various MOFs against various OPPs can be constructed on the basis of parameters used in this study.

Chlorpyrifos fate in the Arctic: Importance of analyte structure in interactions with Arctic dissolved organic matter

The insecticide and current use pesticide chlorpyrifos (CLP) is transported via global distillation to the Arctic where it may pose a threat to this ecosystem. CLP is readily detected in Arctic environmental compartments, but current research has not studied its partitioning between water and dissolved organic matter (DOM) nor the role of photochemistry in CLP's fate in aquatic systems. Here, the partition coefficients of CLP were quantified with various types of DOM isolated from the Arctic and an International Humic Substances Society (IHSS) reference material Suwannee River natural organic matter (SRNOM). While CLP readily partitions to DOM, CLP exhibits a significantly higher binding constant with Arctic lacustrine DOM relative to fluvial DOM or SRNOM. The experimental partitioning coefficients (KDOC) were compared to a calculated value estimated using poly parameter linear free energy relationship (pp-LFER) and was found to be in good agreement with SRNOM, but none of the Arctic DOMs. We found that Arctic KDOC values decrease with increasing SUVA254, but no correlations were observed for the other DOM compositional parameters. DOM also mediates the photodegradation of CLP, with stark differences in photo-kinetics using Arctic DOM isolated over time and space. This work highlights the chemo-diversity of Arctic DOM relative to IHSS reference materials and highlights the need for in-depth characterization of DOM that transcends the current paradigm based upon terrestrial and microbial precursors.

The situation of chlorpyrifos in Mexico: a case study in environmental samples and aquatic organisms

Chlorpyrifos (CPF) is one of the most commonly used organophosphate pesticides. Because CPF was described as a toxic compound without safe levels of exposure for children, certain countries in Latin America and the European Union have banned or restricted its use; however, in Mexico it is used very frequently. The aim of this study was to describe the current situation of CPF in Mexico, as well as its use, commercialization, and presence in soil, water, and aquatic organisms in an agricultural region of Mexico. Structured questionnaires were applied to pesticide retailers to determine the sales pattern of CPF (ethyl and methyl); in addition, monthly censuses were conducted with empty pesticide containers to assess the CPF pattern of use. Furthermore, samples of soil (48 samples), water (51 samples), and fish (31 samples) were collected, which were analyzed chromatographically. Descriptive statistics were performed. The results indicate that CPF was one of the most sold (3.82%) and employed OP (14.74%) during 2021. Only one soil sample was found above the CPF limit of quantification (LOQ); in contrast, all water samples had CPF levels above the LOQ (x̄ = 4614.2 ng/L of CPF). In the case of fish samples, 6.45% demonstrated the presence of methyl-CPF. In conclusion, the information obtained in this study indicates the need for constant monitoring in the area, since the presence of CPF in soil, water, and fish constitutes a threat to the health of wildlife and humans. Therefore, CPF should be banned in Mexico to avoid a serious neurocognitive health problem.

The impact of chemical pollution on the European eel (Anguilla anguilla) from a Mediterranean hypersaline coastal lagoon

The European eel (Anguilla anguilla) is a critically endangered species. The impact of environmental contamination on this species has been highlighted as contributing to the decline in recruitment. The Mar Menor hypersaline coastal lagoon (SE Spain) is one of the most productive fisheries of European eel in Europe, making it a critical habitat for species conservation. The present study aimed to provide an initial overview of the impact of organic chemical contaminants on the European eel and the potential sublethal effects of chemical pollution on pre-migrating eels in this hypersaline habitat. We investigated muscle bioaccumulation of main persistent and hazardous organic contaminants (including some current-use pesticides) and genotoxicity, neurotoxicity, and xenobiotic detoxification system responses. The findings show that lagoon eels were exposed to high levels of legacy organochlorine contaminants, recently banned pesticides (chlorpyrifos), and some emerging chemicals. Some individuals surpassed the maximum levels of CBs authorized by the European Commission for human consumption. In this species, residuals of chlorpyrifos, pendimethalin, and chlorthal dimethyl have been reported for the first time. This field study provides relevant data to stock management and human health consumption and provides the first biomarker responses in European eel under permanent hypersaline conditions. Furthermore, the high frequency of micronuclei in peripheral erythrocytes of lagoon eels indicates sublethal genotoxic effects on the organism. Overall, the European eels growing and maturing in the Mar Menor lagoon are exposed to toxic and carcinogenic chemicals. The lack of seafood safety regulations for human consumption for some legacy chemicals that were measured in high concentrations in our study requires special action. Further biomonitoring and research are recommended to protect the animal, public, and environmental health.

Exposure to pesticide components causes recurrent pregnancy loss by increasing placental oxidative stress and apoptosis: a case-control study

We investigated the plasma levels of pesticides components namely polychlorinated biphenyls (PCBs), dieldrin, dichlorodiphenyldichloroethylene (DDE), ethion, malathion, and chlorpyrifos in recurrent pregnancy loss (RPL) cases, and tested their associations with placental oxidative stress (OS) biomarkers [nitric oxide (NO.), thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), and superoxide dismutase (SOD)] and with placental apoptotic/antiapoptotic indices (Bcl-2 and caspase-3), and evaluated their possible cut-off points to distinguish RPL cases. The study recruited 101 pregnant women divided into; G1 [n = 49, control, normal 1st-trimester pregnancy, normal obstetric history with at least one previous normal live birth], G2 [n = 26, cases with missed abortion (< 3 abortions) before 24 weeks of gestation], and G3 [n = 26, cases with missed abortion (≥ 3 abortions) before 24 weeks of gestation]. The plasma pesticide levels were analyzed by gas chromatography-mass spectrometry. Plasma human chorionic gonadotrophin (HCG), placental OS, Bcl-2, and caspase-3, were analyzed by their corresponding methods and kits. Plasma PCBs, DDE, dieldrin, and ethion levels were significantly higher in RPL cases than in normal pregnancies (p ≤ 0.001). These levels correlated positively with placental OS and apoptosis and negatively with plasma HCG levels. Also, these levels were reliable markers of risk to RPL. Malathion and chlorpyrifos were not detected in any of the study's participants. Pesticides may be risk factors in cases of spontaneous RPL cases. They are associated with an increasing placental OS and placental apoptosis. Specific measures should be taken to decrease maternal exposure to these pollutants' sources, especially in underdeveloped and developing countries.

Modeling fate and transport of pesticides from dryland agriculture using SWAT model

The aim of this study was to understand pesticide fate and transport from dryland agriculture in a major drinking water basin using SWAT and to identify critical source areas in the basin. Hydrological calibration results indicated satisfactory simulation of hydrologic processes within the catchment. Long term average observed sediment values (0.16 ton/ha) were compared with the annual average simulated SWAT outputs (0.22 ton/ha). Generally, the simulated concentrations were higher than the observed values, but the distribution pattern and trends were similar among the months. Average concentrations in water were 0.036 μg/L and 0.006 μg/L for fenpropimorph and chlorpyrifos, respectively. Transfer rates of pesticides from landscape to rivers showed that 0.36% of fenpropimorph and 0.19% of the applied amount of chlorpyrifos were exported to the river. Higher amount of fenpropimorph transport from land to the reach was attributed to its lower K_oc (soil adsorption coefficient) value compared to chlorpyrifos. Higher amounts from HRUs were observed in the application month (April) and following month (May) for fenpropimorph, while the months after September showed higher amounts for chlorpyrifos. The specific HRUs (Hydrological Response Units) located in sub-basins 3, 5, 9 and 11 presented highest dissolved pesticide amounts, while HRUs in sub-basins 4 and 11 exhibited highest concentrations for adsorbed pesticides. Best management practices (BMPs) were recommended in critical subbasins to protect the watershed. Despite the limitations, the results demonstrate the potential contributions of modeling in terms of assessing pesticide loadings, critical zones and application timing.