Search Results (33)

Tomatoes are among the most widely consumed and economically significant fruits in the world. However, the extensive use of pesticides in their cultivation has led to the contamination of the peels, posing potential health risks to consumers. As one of the top global producers, consumers, and exporters of tomatoes, Mexico requires rapid, non-destructive, and real-time methods for pesticide monitoring. In this study, a detailed characterization of six pesticides using Raman and Fourier Transform Infrared (FT-IR) spectroscopies was carried out to identify their characteristic vibrational modes. The pesticides examined included different chemical classes commonly used in tomato cultivation: organophosphorus (dichlorvos and methamidophos), pyrethroids (lambda-cyhalothrin and cypermethrin), and carbamates (methomyl and benomyl). Tomato peel samples were examined both before and after pesticide application. Prior to treatment, the peel exhibited a well-organized polygonal structure and showed the presence of carotenoid compounds. After pesticide application, no visible structural damage was observed; however, distinct vibrational bands enabled the detection of each pesticide. Organophosphorus pesticides could be identified through vibrational bands associated with P-O and C-S bonds. Pyrethroid detection was facilitated by benzene ring breathing modes and C=C stretching vibrations, while carbamates were identified through C-N stretching contributions. Phytotoxicity testing in the presence of pesticides indicates no significant damage during the germination of tomatoes. Full article

Vermipsyllid parasitize the body surface of sheep, feeding on blood and transmitting diseases, causing severe economic losses to the livestock industry. An outbreak of sheep Vermipsyllid fleas in the mountain pastures of Xinjiang’s Altai region showed that several commonly used commercial anthelmintic drugs had poor therapeutic effects on the prevalent flea species. This study first conducted species identification of Vermipsyllid through morphological analysis of 200 female and 40 male specimens collected from the Altai region, followed by molecular biological identification of 6 randomly selected fleas (3 females and 3 males). Finally, pharmacodynamic experiments were performed to screen for highly effective anthelmintic drugs. Ninety Altai multiparous ewes infected with Vermipsyllid were divided into six groups (fifteen sheep per group): an untreated control group (Ctr), avermectin injection group (Group I), ivermectin injection group (Group II), moxidectin pour-on group (Group III), cypermethrin pour-on group (Group IV), and dichlorvos pour-on group (Group V), with a 14-day trial period. On Day 0, each group received a single treatment according to drug instructions and specified dosages. The number of fleas, flea population reduction rates, and cure rates were measured on Day 0, Day 3, Day 7, and Day 14 to screen for effective anthelmintic drugs. Results showed that unfed female and male fleas were grayish-brown. Engorged females reached 14.15 mm in size, appearing pale white or yellow, with their sterna maintaining the original size and shape despite abdominal distension. Female fleas had 20–21 segments on the labium, while males had 16–19 segments. The hind tibiae featured four notches, and each side of the tergite had 13 ± 1 cup-like indentations. Molecular biological identification indicated that the identified fleas belonged to D. ioffi (Vermipsyllidae, Dorcadia Ioff), showing 99.13% sequence similarity with D. ioffi from Xinjiang, China. In pharmacodynamic experiments, the number of D. ioffi in Groups IV and V decreased to zero on both Day 7 and Day 14, which was extremely significantly lower than other groups (p < 0.01). The flea population reduction rates in Groups IV and V reached 100% on both days. By Day 14, the cure rates of Groups I, II, and III were 0%, while those of Groups IV and V were 100%. Avermectin injection, ivermectin injection, and moxidectin pour-on showed poor anthelmintic effects, whereas cypermethrin and dichlorvos pour-on exhibited high anthelmintic activity against this flea species. Full article

The design of efficient and stable visible-light-driven photocatalysts is paramount for sustainable hydrogen (H₂) evolution and the degradation of organophosphorus pesticides, exemplified by dichlorvos (DDVP). In this work, we synthesized a co-catalyst-free nanocomposite photocatalyst composed of Al₆Si₂O₁₃ (ASO) and Cd_8.05Zn_1.95S₁₀ (ZCS). By constructing a Type-I heterojunction, the optimized ASO/ZCS-1 nanocomposite (ASO loading ratio: 30%) enhanced visible-light-driven H₂ evolution activity (5.1 mmol g⁻¹ h⁻¹), nearly doubling that of pristine ZCS (2.7 mmol g⁻¹ h⁻¹). Stability assessments revealed catalytic durability for ASO/ZCS-1 over five successive cycles, whereas the activity of pure ZCS precipitously declined to 59.7% of its initial level. Additionally, ASO, ZCS, and ASO/ZCS-2 (ASO loading ratio: 50%) demonstrated notable photocatalytic efficiency toward DDVP degradation without any co-catalyst, reducing DDVP concentration to 56.2% (ASO), 18.9% (ASO/ZCS-2), and 38.4% (ZCS), with corresponding degradation stability of 93.8%, 95.1%, and 93.8%, respectively. These results underscore the superior photocatalytic activity and stability of ASO, ZCS, and ASO/ZCS in the remediation of organophosphorus pesticides, with the Type-I heterojunction structure of ASO/ZCS enhancing both degradation activity and stability. Comprehensive characterizations by X-ray photoelectron spectroscopy (XPS), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), and differential charge density analyses verified the Type-I heterojunction charge-transfer mechanism, effectively suppressing charge recombination and thus improving photocatalytic performance. Consequently, ASO/ZCS nanocomposites exhibit significant promise for broad applications in sustainable H₂ production, pollutant degradation, and ensuring food and agricultural product safety. Full article

Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, DDVP) is a highly toxic organophosphorus insecticide, and its persistence in air, water, and soil poses potential threats to human health and ecosystems. Covalent triazine frameworks (CTFs), with their sufficient visible-light harvesting capacity, ameliorated charge separation, and exceptional redox ability, have emerged as promising candidates for the photocatalytic degradation of DDVP. Nevertheless, pure CTFs lack effective oxidative active sites, resulting in elevated reaction energy barriers during the photodegradation of DDVP. In this work, density functional theory (DFT) calculations were employed to investigate the impact of various oxygen-containing acid groups (-COOH, -HSO₃, -H₂PO₃) on DDVP photodegradation performance. First, simulations of the structure and optical properties of modified CTFs reveal that oxygen-containing acid groups induce surface distortion and result in a redshift in the absorption edge. Subsequently, analysis of the density of states, frontier molecular orbitals, surface electrostatic potential, work function, and dipole moment demonstrates that oxygen-containing acid groups enhance CTF polarization, facilitate charge separation, and ameliorate their oxidative capability. Additionally, the free-energy diagram of DDVP degradation uncovers that oxygen-containing acid groups lower the energy barrier by elevating the adsorption and activation capability of DDVP. Notably, -H₂PO₃ presents optimal potential for the photodegradation of DDVP by unique electronic structure and activation capability. This work offers a valuable reference for the development of oxygen-containing acid CTF-based photocatalysts applied in degrading toxic organophosphate pesticides. Full article

Honey, a natural food with a rich history, is produced by honeybees and other species of bees from nectar, other plant fluids, and honeydew of sap-sucking insects. During foraging, these bees may be exposed to plant protection products (PPPs), metals, and metalloids, potentially leading to residues in honey and hive products that could have a negative impact on human safety. Recognizing the lack of an appropriate methodology for pesticide contamination of honey and other hive products, this research aims to support the need for studies on residues in pollen and bee products for human consumption to establish safe maximum residue levels (MRLs) for consumers. A UHPLC-MS/MS residues method and a modified QuEChERS extraction were applied to simultaneously determine 237 pesticide residues in honey and pollen. The study in North Sardinia analyzed honey and pollen samples from six areas for pesticide residues and verified 27 heavy metals and metalloid residues using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The data obtained showed residues at levels close to the LOQ of the method, cycloate in a few samples of pollen, and dichlorvos, zoxamide, cycloate, and chlorantraniliprole in honey samples. All samples showed the absence of heavy metal contamination. Overall, no risk to human health was identified. The results of this study confirm that honey and pollen may be a good bioindicator of environmental contamination of a wide area surrounding honeybee hives. Full article

The use of pesticides for the prevention and eradication of a variety of pests has been on the increase, hence the need for investigations on their impact on the environment and non-target organisms. Fractions of the 24 h LC₅₀ of dichlorvos in the form of ${\displaystyle \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}$ (LC₅₀), ${\displaystyle \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$4$}\right.}$ (LC₅₀), ${\displaystyle \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$8$}\right.}$ (LC₅₀) and ${\displaystyle \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$16$}\right.}$ (LC₅₀) were determined to achieve varying concentrations for this study, and ten Anodonta marginata were placed in each aquarium for the definitive test, with each treatment concentration set up in triplicates. The setup was monitored daily for four days (96 h) for changes in behavioural and biochemical responses. Behavioural responses such as opening of the shell, extension of the foot, complete shell closure, and activity of enzymes such as AChE and GSH were determined as endpoint biomarkers in A. marginata tissue. An analysis of variance was used to determine significant variations in behavioural responses, survival, GSH and AChE content in bivalves across varying concentrations of dichlorvos. The exposure of A. marginata to varying concentrations (0, 10, 20, 40 and 70 mg/L) of dichlorvos for 96 h led to an LC₅₀ value of 4.79 mg/L when compared to exposure concentrations. There was a significant (p < 0.05) variation in biochemical responses and opening of the shell as a behavioural response in A. marginata across varying concentrations of dichlorvos with time, with the highest percentage shell opening and GSH activity recorded at the highest concentration (70 mg/L) of dichlorvos and time (96 h). In contrast, AChE activity and percentage survival of A. marginata were lowest at the highest concentration of dichlorvos, confirming dichlorvos as an AChE inhibitory organophosphate pesticide. There is a need for proper monitoring and management of pesticide contamination in order to protect freshwater ecosystems. Full article

Dichlorvos (DDVP) is an organophosphorus pesticide commonly used in agriculture for pest control, which may enter the organism from the food chain and cause harm. This study aimed to investigate the mitigation effect of Lactiplantibacillus plantarum CCFM8661 (a strain of the bacteria) on DDVP toxicity. Sixty male mice were randomly divided into five groups including control (saline), model (DDVP), low-dose, medium-dose, and high-dose groups, and alleviating effect was evaluated by determining body weight, pesticide residues, oxidative stress, and inflammation, and by histological analysis. The results showed that compared with the model group, body weight and acetylcholinesterase activity, and SOD, CAT, T-AOC, and GSH levels significantly increased, and serum DDVP content, MDA level, IL-1β, and TNF-α significantly decreased after administration of the L. plantarum CCFM8661. The study demonstrated that L. plantarum CCFM8661 exhibited a significant detoxification effect on pesticide toxicity in mice, providing a theoretical basis for the application of probiotics in mitigating pesticide-induced damage. Full article

In this study, we developed novel BiOBr/WO_2.72 nanocomposites (abbreviated as BO/WO) and systematically investigated their photocatalytic degradation performance against the pesticide dichlorvos under visible light irradiation. The experimental results demonstrated that the BO/WO nanocomposites achieved an 85.4% degradation of dichlorvos within 80 min. In comparison, the BO alone achieved a degradation degree of 66.8%, and the WO achieved a degradation degree of 64.7%. Furthermore, the BO/WO nanocomposites retained 96% of their initial activity over five consecutive cycles, demonstrating exceptional stability. Advanced characterization techniques, such as high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) confirmed the composition and catalytic mechanism of the composite material. The findings indicated that the BO/WO nanocomposites, through their optimized Type-I heterojunction structure, achieved efficient separation and transport of photogenerated electron–hole pairs, significantly enhancing the degree of degradation of organophosphate pesticides. This research not only propels the development of high-performance photocatalytic materials, but also provides innovative strategies and a robust scientific foundation for mitigating global organophosphate pesticide pollution, underscoring its substantial potential for environmental remediation. Full article

In the wake of rapid advancements in the pharmaceutical, food, and agricultural industries, the environment faces an increasing influx of diverse compounds, both intentionally and unintentionally released. These compounds fall into two categories: persistent and emerging pollutants. Persistent pollutants, characterized by their resistance to degradation and potential to accumulate in the environment, pose serious ecological threats. The Water Framework Directive (WFD) plays a pivotal role in monitoring and regulating these substances. This review discusses various contemporary analytical approaches to determine problematic substances, including benzo(a)pyrene, cypermethrin, dichlorvos, heptachlor, and heptachlor epoxide, aligning with the priorities outlined in the 2013 WFD classification. This review focuses on diverse water sampling methods, sample preparation techniques, and analytical methods, encompassing chromatographic, spectroscopic, and electrochemical approaches, with the primary goal of achieving the requirement laid on analytical methods used for the determination of maximum allowable concentrations defined in the WFD. Chromatographic methods, utilizing diverse mass spectrometers, have achieved detection limits as low as 10⁻⁶ μg/L, while modern electroanalytical techniques reach levels as low as 10⁻¹³ μg/L, reflecting an ongoing collective effort to enhance monitoring and safeguard the health of aquatic ecosystems. From sampling methods, large-volume sampling and passive sampling devices have been shown to be a cost-effective and modern solution, addressing limitations in traditional sampling methods, even if both of them face important pros and cons in terms of quantitative analysis. Full article

We performed a thorough systematic review of published literature to determine potential links between human health impacts and naled, a registered adult mosquito control product (adulticide), and its major degradate, dichlorvos (DDVP). A search query was performed on 8 September 2023, capturing all articles published up to that date on the Scopus and PubMed databases. Inclusion criteria were the presence of either pesticide and a measured or modeled human health outcome or risk. The search string resulted in 382 articles; however, 354 articles were excluded, resulting in only 28 articles that met the inclusion criteria. The studies that directly relate to aerosolized ultra-low volume (ULV) mosquito control applications did not report any associated deleterious human health outcomes. Results from the reviewed papers displayed no negative health effects or led to inconclusive results. No studies showed adverse health effects from aerial ULV applications for mosquito management. Our findings are congruent with the United States Environmental Protection Agency and Centers for Disease Control and Prevention recommendations that aerial applications of naled, following label parameters, do not pose an adverse risk exposure to humans, wildlife, and the environment. Full article

There is a severe lack of information about molecular mechanisms of pesticide resistance in the rust-red flour beetle, a major pest destroying grains and flour across Nigeria, hindering evidence-based control. Here, we identified to the species level three populations of the red flour beetle from Kano, Nigeria, as Tribolium castaneum (Herbst 1797) and investigated the mechanism driving their insecticide resistance. The IRAC susceptibility bioassays established cypermethrin resistance, with LC₅₀s of 4.35–5.46 mg/mL in the three populations, NNFM, R/Zaki and Yankaba. DDT and malathion resistance were observed in NNFM, with LC₅₀s of 15.32 mg/mL and 3.71 mg/mL, respectively. High susceptibility was observed towards dichlorvos in all three populations with LC₅₀s of 0.17–0.35 mg/mL. The synergist bioassay with piperonylbutoxide significantly restored cypermethrin susceptibility, with mortality increasing almost threefold, from 24.8% obtained with 1.5 mg/mL of cypermethrin to 63.3% in the synergised group (p = 0.013), suggesting a preeminent role of P450s. The two major knockdown resistance (kdr) mutations, T929I and L1014F, in the IIS4 and IIS6 fragments of the voltage-gated sodium channel were not detected in both cypermethrin-alive and cypermethrin-dead beetles, suggesting a lesser role of target-site insensitivity mechanisms. These findings highlight the need to explore alternative control tools for this pest and/or utilise synergists, such as piperonyl butoxide, as additional chemistries in pesticide formulations to improve their efficacy. Full article

Colorimetry is an important on-site detection method for organophosphorus compounds. O-Ethyl S-(2-diisopropylaminoethyl) methylphosphonothioate (VX) is recognized as one of the deadliest organophosphorus chemical agents, and the rapid on-site detection of VX is of great significance to public safety. In this paper, a squaraine derivative was synthesized as probe molecules, and the sensing characteristics of VX in a colorimetric solution system containing tetrabutylammonium fluoride (TABF) were studied with UV−Vis spectroscopy, nuclear magnetic resonance (¹H NMR), and mass spectrometry. The results showed that the binding of the thiol moiety of VX to the quaternary ring of the squaraine probe changed the molecular conjugation system, and that the rapid colorimetric detection of micro-trace VX was achieved based on color change before and after interaction with squaraine, enabling the detection limit of VX to be as low as 0.4 μg/mL. Moreover, the colorimetry method also possessed satisfactory sensitivity and could detect VX from other organophosphorus pesticides (e.g., parathion and dichlorvos), phosphorus-containing reagents (e.g., diethyl chlorophosphate and dimethyl methylphosphonate), a benzene series (e.g., toluene), and acid and base agents (e.g., acetic acid and triethylamine, respectively), which demonstrated that squaraine-based colorimetry could provide fast, on-site measurement results for VX detection. The strategy of this research could be extended as a common approach for the detection of other organophosphorus nerve agents or organophosphorus pesticides. Full article

Introduction: Because of the longer growing season and warmer climate, weeds and insect pests spread are on the rise, thereby increasing the demand for pesticide use and consequently harmful emissions that further exacerbate climate change. Unsafe occupational exposure to pesticide residue is associated with a lack of product knowledge and safety awareness among farmers in low- and middle-income countries (LMICs). Materials and Methods: A cross-sectional descriptive study design was adopted for this study in which a face-to-face administered questionnaire was used to collect data from 285 respondents who were selected using convenient snowball sampling technique. Knowledge, awareness, and practices related to pesticide storage, handling, application, and containers disposal among the farmers were measured. Categorical variables were analysed and presented using descriptive statistics in the form of frequency count and percentage, while numeric items were summarized using mean and standard deviation. Results: Dichlorvos and Perfekthion 2.5 EC listed in the WHO Group I pesticide classification were among the most frequently used pesticides. Symptoms of pesticide intoxication reported include headaches (56.1%), dizziness (56.5%), skin irritation (53.3%), and fatigue (45.6%), respectively. Farmers’ behaviour during pesticide application include blowing clogged nozzle with mouth (42.7%), talking while spraying (59.8%), and mixing pesticide with bare hands (31.1%). Furthermore, 38.5% of them use pesticide containers for other domestic purposes. Conclusions: Socioeconomic factors, i.e., educational level, age, and years of farm practice, influenced farmers safety behaviour. Based on these findings, an approach that will help strengthen capacity building programmes and the enhancement of knowledge-based initiatives around the adoption of non-synthetic pest-control methods should be encouraged. Full article

Organophosphate pesticides (OPs) are highly toxic; their presence in surface waters is a matter of great concern. To the best of our knowledge, OPs in wastewater from agrochemical manufacturing facilities (AMFs) and influents and effluents from agrochemical wastewater treatment plants (AWWTPs) have not been previously investigated. Therefore, we investigated the presence of 8 OPs (5 of which are regulated under the Water Environment Conservation Act (WECA)) in 15 AMFs and 13 AWWTPs detected through surface water monitoring and proposed measures for effectively regulating these OPs in AWWTPs. Five OPs (chlorpyrifos, diazinon, dichlorvos, EPN, and fenitrothion) were detected in the AMF and AWWTP influents; three (methyldemeton, parathion, and phenthoate) were not. Of the five detected OPs, chlorpyrifos, dichlorvos, and fenitrothion are not currently regulated via effluent limitations for WWTPs under WECA; thus, additional regulations are required. The most effective process configuration for the removal of these OPs was biological treatment through activated sludge processes, followed by activated carbon adsorption. In the system, 100% OP removal from the AWWTP influents was observed. This treatment technology can be implemented in AWWTPs to minimize the presence of OPs in surface waters, thereby protecting human health and aquatic life. Full article