Persistent Pesticides Research Articles

Spatiotemporal Dynamics of Trunk-Injected Pesticide Residue for Management of Pine Wilt Disease in Pinus koraiensis

This study focused on the persistence, distribution, and efficacy of trunk-injected pesticides in Pinus koraiensis (Korean pine) with regard to controlling pinewood nematodes (PWNs, Bursaphelenchus xylophilus), the causative agent of pine wilt disease (PWD). In this study, we compared pesticide residues in the needles and branches of Korean pine, revealing significant declines in pesticide residues over time after treatments were applied. Notably, abamectin residues decreased from 0.2325 mg/kg to 0.0901 mg/kg in branches over a period of 18 months. In contrast, emamectin benzoate showed a variation in residue decline depending on the formulation, with the residue level in branches decreasing from 0.1220 mg/kg to 0.0328 mg/kg over the same period. From a spatial perspective, the results revealed minimal differences in pesticide residue at varying tree heights, although a decrease in upper canopy residue was observed in some cases. The nematicidal efficacy test demonstrated that none of the treated trees developed PWN symptoms. Overall, the findings suggest that the trunk-injected pesticides abamectin and emamectin benzoate can persist for two years, with the residue levels being sufficient to prevent PWN propagation, even when the levels are below critical inhibition concentrations.

Global meta-analysis and machine learning reveal the critical role of soil properties in influencing biochar-pesticide interactions

Biochar application in soils is increasingly advocated globally for its dual benefits in enhancing agricultural productivity and sequestering carbon. However, lingering concerns persist regarding its environmental impact, particularly concerning its interactions with pesticide residues in soil. Previous research has fragmentarily indicated elevated pesticide residues and prolonged persistence in biochar-amended soil, suggesting a potential adverse consequence of biochar application on pesticide degradation. Yet, conclusive evidence and conditions for this phenomenon remain elusive. To address this gap, we conducted a comprehensive assessment using meta-analysis and machine learning techniques, synthesizing data from 58 studies comprising 386 observations worldwide. Contrary to initial concerns, our findings revealed no definitive increase in pesticide concentrations in soil following biochar application. Moreover, a significant reduction of 66 % in pesticide concentrations within soil organisms, such as plants and earthworms, was observed. The quantitative analysis identified soil organic matter content as a key factor influencing biochar-pesticide interactions, suggesting that applying biochar to soils rich in organic matter is less likely to increase pesticide persistence. This study provides a critical assessment of the environmental fate of pesticides under biochar application, offering valuable guidance for the optimal utilization of both pesticides and biochar in sustainable agricultural practices.

Effect of Chlorantraniliprole on Life History Traits and Relative Fitness of Laboratory-Selected Resistant and Susceptible Populations of Spodoptera litura (Lepidoptera: Noctuidae).

Insecticides are widely used to control pests and improve agricultural yield. The use of indiscriminate amounts and persistent pesticides has not only resulted in insect pest resistance challenges but has also harmed non-target organisms and contaminated the environment. We assessed the cost-effectiveness of Spodoptera litura (Fabricius) resistance to chlorantraniliprole (CTPR) as part of insect resistance control programs. S. litura larvae were collected from the fields and treated with chlorantraniliprole for 15 generations. Compared to the unselected population (Unsel-Lab), the chlorantraniliprole-selected population (CTPR-Sel) of S. litura exhibited a resistance level of 98.23 times. The findings demonstrated that the chlorantraniliprole-resistant genotype had lower egg-to-adult survivability, longer egg-to-adult developing times, and lower fecundity than the chlorantraniliprole-susceptible genotype. Compared to the Unsel-Lab population, the CTPR-Sel population of S. litura had a poorer relative fitness (0.44) at LC30 and shorter male/female longevity. Demographic parameters, including net reproductive rate (R0) and intrinsic (rm) and finite rate of increase (λ), were lower in the CTPR-Sel strain than in Unsel-Lab S. litura. These findings demonstrate that chlorantraniliprole resistance in S. litura has fitness costs at the individual and population levels, implying that removing the selecting agent from the environment might result in less resistance and opportunities for susceptibility restoration. As a result, the current work could help to determine effective management strategies to prevent chlorantraniliprole resistance in S. litura.

Characterization of SrMoO4 synthesized at different temperatures and its photocatalytic performance toward Carbendazim fungicide degradation under UV light

The Scheelite SrMoO4 synthesized by co-precipitation, non-calcined and calcined at different temperature (500 – 800 °C) has been characterized physically and photoelectrochemically. The XRD analysis showed the formation of single phase at room temperature (SMO), crystallizing in a tetragonal structure and the oxide is thermally stable after calcination at 500 °C (SMO5) and 800 °C (SMO8). The crystallites size (D) increases with increasing thee calcination temperature (TC). The Raman spectra presents the characteristic vibrations of the tetragonal structure. Although its low temperature (TC), the specific surface area calculated by the BET method for SMO is weak (4.61 m2 g−1). The SEM images showed the effect of the temperature TC on the morphology of SrMoO4 and as expected the grain size increases with increasing TC. Diffuse reflectance showed a wide optical gap (4.26 eV) for SMO, in accordance with its white color and decreases only slightly (4.10 eV) with increasing TC. The points of zero charge (PZC) calculated by the Drift method for SMO, SMO5 and SMO8 are 5.92, 6.13 and 6.70 respectively. The photocatalytic properties of the powders were assessed through the degradation of Carbendazim (MBC), a hazardous and persistent pesticide, under UV irradiation (λmax = 365 nm). The degradation reached an abatement of 96 % after 15 min under optimal conditions ([SMO] = 0.8 g/L, [MBC] = 8 mg/L, at room temperature and natural pH 5.7) and increasing TC, reduces the degradation capacity of SrMoO4. The oxidation mechanism was elucidated by using scavengers and liquid chromatography (LC-MS/ESI) which showed that the holes (h+) and •OH radicals are responsible for the MBC degradation. The Total Organic Carbon (TOC) reached 70 % for the same period.

Mobility and persistence of pesticides and emerging contaminants in age-dated and redox-classified groundwater under a range of land use types

Understanding groundwater contamination patterns is hampered by the heterogeneous groundwater age and redox status over the depth range typically sampled for identifying pesticides and emerging contaminants threats. This study explores depth patterns of groundwater age and redox status across various land use types, unraveling spatial and temporal trends of pesticides and emerging contaminants using data from groundwater quality monitoring in the south of the Netherlands. The Netherlands is an ideal testing ground due to its high population density and widespread groundwater contamination from multiple sources. 146 multi-level observation wells were age-dated using 3H/3He, and contaminant concentrations were analyzed based on recharge year, land use type, and redox conditions, mitigating uncertainties from spatial and depth-dependent variations in both groundwater age and redox status. Redox-recharge year diagrams were developed to visually evaluate contaminant patterns in relation to these factors and to assess concentration patterns in relation to contamination history. Most detections of pesticides, metabolites, and emerging contaminants occurred in the youngest recharge periods (2000–2010 and 2010–2020) and in agricultural areas. However, certain contaminants, including BAM, desphenyl-chloridazon, short-chain PFCAs, PFOA, and EDTA, were consistently found in older water and Fe- or SO4-reduced conditions, indicating their mobility and persistence in the regional groundwater system. Comparing the presence of contaminants in specific redox classes and recharge periods with known application or leaching history provides insights into retardation (e.g., PFOS) and degradation (e.g., 2-hydroxy-atrazine, benzotriazole), explaining lower detection frequencies in earlier recharge periods. Identifying recharge years from age-dated groundwater helps relate contaminants to farmland application or river water recharge periods, revealing leaching history and contamination origins. The presented framework has the potential to enhance the interpretation of large groundwater datasets from dedicated, short-screened observation wells, such as those from the Danish GRUMO network, the Dutch monitoring networks, and parts of the US National Water Quality Program.

Pesticide contamination patterns in Montagu's harrier (Circus pygargus) chicks.

Biomonitoring of persistent pesticides in birds of prey has been carried out for decades, but few studies have investigated their relevance for the monitoring of non-persistent pesticides. Herein, we determined the contamination patterns of multiple pesticides in Montagu's harrier (Circus pygargus) chicks in an intensive farming area of southwestern France. Blood samples from 55 chicks belonging to 22 nests in 2021 were assessed for 104 compounds (herbicides, fungicides, insecticides, safeners and synergists). All chicks had at least one herbicide in their blood, and half had at least two compounds. The 28 compounds detected comprised 10 herbicides, 12 fungicides, 5 insecticides and 1 synergist. Mixtures in blood were predominantly composed of herbicides, and six chicks presented a mixture of the three pesticide classes. The most prevalent compounds were sulcotrione (96% of chicks), tebutam (44%) and chloridazon (31%), of which the latter two had been banned in France for 19 and 3years, respectively, at the time of sampling. Most compounds are considered non-acutely toxic, but sulcotrione is potentially carcinogenic, mutagenic and reprotoxic, raising questions about the effects on the health of nestlings. Biomonitoring of multiple pesticides through Montagu's harrier chicks in agroecosystems is clearly relevant because it reflects the general pattern of agricultural pesticide use in the study area. It also raises questions about exposure pathways in chicks, and further investigations are needed to disentangle the roles of dietary routes and maternal transfer for the established pesticide contamination patterns.

Environmentally Friendly Biocomposites for The Adsorption of Mancozeb Pesticide from Water

Objective: Developing polyurethane foams and composites incorporating petroleum catalyst residue (RC) and rice husk ash (RHA) to adsorb the pesticide mancozeb from water. Theoretical Framework: The annual global consumption of pesticides reaches 2.6 million tons, resulting in significant environmental impacts. Not only does this excess increase health risks, but the persistence of pesticides in water bodies emphasizes the need for effective alternatives for their removal, such as adsorption using polyurethane foams. Method: The polyurethane composites were synthesized with the incorporation of 20% and 50% of RC and RHA waste, respectively, in relation to the total mass of polyols. Characterization analyses were carried out using thermogravimetry, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The composites were immersed in aqueous solutions of mancozeb at a concentration of 500 ppm, stirred for 24 hours at 150 rpm and the solution analyzed by UV-Vis. Results and Discussion: The foams showed chemical and dimensional stability. The composites synthesized with a high amount of waste incorporated achieved greater adsorption capacity. Research Implications: Este trabalho promove a economia circular ao desenvolver compósitos de poliuretano que incorporam resíduos para a remoção eficiente de pesticidas da água. Originality/Value: The results are promising for the use of waste in the production of sustainable polyurethane foams that can be applied in the water purification process.

Persistent pesticides exposure and cardiometabolic outcomes among middle-aged Latina women in an agricultural community: The CHAMACOS Maternal Cognition Study

Persistent pesticides exposure and cardiometabolic outcomes among middle-aged Latina women in an agricultural community: The CHAMACOS Maternal Cognition Study

Progress in analytical methods for pesticide detection in palm oil and palm kernel oil matrices, and pesticide fate studies in oil palm plantations

AbstractThis review presents a comprehensive overview of instrumental analyses for both single‐component and multicomponent pesticide detection within palm oil matrices. It meticulously examines the analytical attributes of these methods across various pesticide categories, including insecticides, herbicides, and fungicides. The discussion extends to sample preparation methodologies tailored for palm oil, encompassing techniques such as low‐temperature precipitation followed by solid‐phase extraction, liquid–liquid extraction, and variations of the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method. Additionally, it explores the QuEChERS method employing different sorbent combinations to optimize extraction efficiency. The second part of the review focuses on the fate study of pesticides within oil palm plantations which covers laboratory‐scale simulations elucidating pesticide behavior, comparative analysis of field studies with predictive programs, and investigations into the influence of climatic and microbiological factors on pesticide persistence within the oil palm agroenvironment system.

Persistent organic pollutants and cognitive decline among middle-aged or older adults in the Hispanic Community Health Study/Study of Latinos

Persistent organic pollutants may negatively impact cognition; however, associations between persistent organic pollutants and changes in cognition among United States Hispanic/Latino adults have not been investigated. Herein, we examined the associations between 33 persistent organic pollutants and cognitive changes among 1837 Hispanic/Latino adults. At baseline (2008–2011; Visit 1), participants provided biospecimens in which we measured levels of 5 persistent pesticides or pesticide metabolites, 4 polybrominated diphenyl ethers and 2,2’,4,4’,5,5’-hexabromobiphenyl, and 24 polychlorinated biphenyls. At Visit 1 and again at Visit 2 (2015–2018), a battery of neurocognitive tests was administered which included the Brief-Spanish English Verbal Learning Test, Word Fluency Test, and Digit Symbol Substitution Test. To estimate the adjusted associations between changes in cognition and each POP, we used linear regression for survey data. Each doubling in plasma levels of polychlorinated biphenyls 146, 178, 194, 199/206, and 209 was associated with steeper declines in global cognition (βs range:-0.053 to −0.061) with stronger associations for the Brief-Spanish English Verbal Learning Test. Persistent organic pollutants, in particular polychlorinated biphenyls, were associated with declines in cognition over 7 years and may be a concern for Hispanic/Latino adults.

Over 50 years of a field experiment on cropping systems in Bałcyny, Poland: Assessing pesticide residues in soil and crops from the perspective of their field application history

Many agricultural problems can be illustrated and solved through long-term field experiments. Since 1967, an experiment has been conducted in Bałcyny, Poland, to compare continuous cropping with growing crops in crop rotation. The experiment also provides information on the history of chemical crop protection, which may have influenced soil and crop contamination with pesticide residues. In this study, fields of winter rye in continuous cropping (CCrye) and a 5–6-field crop rotation (CRrye) were used as an example to investigate the occurrence of pesticides in soil and grain in the context of previous use of chemical crop protection products. Two levels of crop protection were also examined: herbicide (since the 1972/73 growing season) and fungicide (since 1982/83) application (HF) and control treatment (CT; no herbicides since 1972/73, no fungicides since 1982/83). Insecticides were used only when absolutely necessary. Between 1967 and 2019, 58 different active substances were applied to the fields selected for this study. Soil and grain samples collected in 2019 after rye harvest were analyzed for the presence of 441 and 496 different substances, respectively. Only DDT and its metabolites were detected in soil, even though DDT was not applied to the fields after 1967. The concentration of ΣDDT (sum of all metabolites and isomers) ranged from 038 to 130 µg kg–1 soil and exceeded the limit set in Poland (120 µg kg–1) under CRrye-HF treatment. In winter rye grain, no pesticide residues were found. The results show that long-term rational use of less persistent pesticides does not lead to contamination of the soil or the test cereal grain, but DDT continues to threaten the environment five decades after its probable last use. The study points to the value of comprehensive long-term recording for providing a retrospective assessment of pesticide exposure. Long-term field experiments facilitate this approach.

Exploring spatial and temporal symptoms of the freshwater salinization syndrome in a rural to urban watershed

The freshwater salinization syndrome (FSS), a concomitant watershed-scale increase in salinity, alkalinity, and major-cation and trace-metal concentrations, over recent decades, has been described for major rivers draining extensive urban areas, yet few studies have evaluated temporal and spatial FSS variations, or causal factors, at the subwatershed scale in mixed-use landscapes. This study examines the potential influence of land-use practices and wastewater treatment plant (WWTP) effluent on the export of major ions and trace metals from the mixed-use East Branch Brandywine Creek watershed in southeastern Pennsylvania, during the 2019 water year. Separate analysis of baseflow and stormflow subsets revealed similar correlations among land-use characteristics and streamwater chemistry. Positive associations between percent impervious surface cover, which ranged from 1.26 % to 21.9 % for the 13 sites sampled, and concentrations of Ca2+, Mg2+, Na+, and Cl− are consistent with road-salt driven reverse cation exchange and weathering of the built environment. The relative volume of upstream WWTP was correlated with Cu and Zn, which may be derived in part from corroded water-conveyance infrastructure; chloride to sulfate mass ratios (CSMR) ranged from ~6.3 to ~7.7× the 0.5 threshold indicating serious corrosivity potential. Observed exceedances of U.S. Environmental Protection Agency Na+ and Cl− drinking water and aquatic life criteria occurred in winter months. Finally, correlations between percent cultivated cropland and As and Pb concentrations may be explained by the persistence of agricultural pesticides that had been used historically. Study results contribute to the understanding of FSS solute origin, fate, and transport in mixed-use watersheds, particularly those in road salt-affected regions. Study results also emphasize the complexity of trace-metal source attribution and explore the potential for FSS solutes to affect human health, aquatic life, and infrastructure.

Дослідження міграції сучасних пестицидів амікарбазону, біциклопірону та підіфлуметофену з ґрунту до ґрунтових вод (результати експериментальних досліджень)

ABSTRACT. The expansion of the range and volume of application of plant protection products in agriculture increases the risk of contamination of soil, and subsequently of underground and surface water sources, especially with highly persistent pesticides in the soil. Аim. Establishing and comparative assessment of migration characteristics of new pesticides — representatives of different chemical classes, from soil to groundwater when modelling different initial concentrations and irrigation regimes. Materials and Мethods. In a laboratory experiment, the migration of the investigated substances in the soil – ground water system was studied with the help of filtration columns designed by the Academician E.H. Honcharuk. Soil Standard Model no 1 (SSM no 1) and leached chernozem were used as arable soil layers. Three hydraulic regimes were simulated: annual, three-month, or monthly precipitation rates were supplied to the column for 30 days. The initial concentrations of amicarbazone, bicyclopyrone, and pydiflumetofen corresponded to both one maximum consumption rate (m.c.r.) and 0.5, 0.2 and 5 m.c.r. respectively. Quantitative determination of the studied substances in the filtrate was carried out by the method of high-performance liquid chromatography. The results. It was established that with higher initial concentrations of all three substances in the topsoil and greater hydraulic load on the filtration column in the case of both herbicides, the concentrations of compounds in the filtrate were higher. At the same time, with the same arable soil layer (SSM no 1) and hydraulic load (maximum) and almost the same initial concentration in the soil (0.05 and 0.06 mg/kg), bicyclopyrone appeared in the filtrate much earlier and in in larger quantities, its maximum concentration in the filtrate was reached much faster, it was 17 times higher. It took much more time to detect pydiflumetofen than bicyclopyrone. The migration levels of bicyclopyrone were almost independent of the type of arable soil layer, while pydiflumetofen in leached chernozem retained longer and migrated more slowly than in SSM no 1. Conclusions. Both general regularities and significant differences in the migration of the studied substances to the ground water depending on the soil profile were revealed. It has been proven that, compared to bicyclopyrone, pydiflumetofen is less mobile, appears in the filtrate much later and migrates from SSM no 1 more slowly. Compared to bicyclopyrone, amicarbazone is more mobile, migrates from leached chernozem longer and more intensively. The highest potential danger of groundwater contamination due to vertical migration from chernozem, the most common soil type in Ukraine, is inherent to amicarbazone, the lowest — to pydiflumetofen. Keywords: plant protection products, herbicide, fungicide, soil, groundwater, migration, pollution, threshold limit value.

Concomitant determination of pesticides in soil and drainage water over a potato cropping season reveal dissipations largely in accordance with respective models

Pesticides are widely used in agriculture where they do not only reach their targets but also distribute to other environmental compartments and negatively affect non-target organisms. To prospectively assess their environmental risk, several tools and models using pesticide persistence (DT50) and leaching potential (groundwater ubiquity score (GUS), EXPOSIT) have been developed. Here, we simultaneously quantified 18 pesticides in soil and drainage water during a conventionally grown potato culture at field scale with high temporal resolution and compared our findings with predictions of the above models. Overall dissipations of all freshly applied compounds in soil were in line with published DT50 field values and their occurrences in drainage water were generally consistent with GUS and EXPOSIT models, respectively. In contrast, soil concentrations of the legacy pesticide atrazine and one of its transformation products (atrazine-2-hydroxy) were constant during the entire sampling campaign. Moreover, during peak discharge atrazine concentrations in drainage water were diluted whereas those of freshly applied pesticides were maximal. This difference demonstrates that the applied risk assessment tools were capable of predicting environmental concentrations and dissipation of pesticides at the short and medium time scale of a few half-lives after application, but fell short of capturing long-term trace residues.

Ecological risk assessment of organochlorine pesticide residues in sediment samples from Lake Tana and Hayqe in Northwest Ethiopia

In most developing countries, including Ethiopia, the excessive use of toxic and persistent pesticides for agricultural and malaria control purposes poses a significant challenge. This study focuses on evaluating the concentration and ecological risks associated with organochlorine pesticides (OCPs) in the sediments of Lake Tana and Hayqe. Employing a laboratory-based cross-sectional approach, the residues of OCPs in sediment samples were extracted using the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method, followed by dispersive solid phase extraction cleanup (d-SPE) techniques and analyzed for 18 OCPs by gas chromatography coupled to tandem mass spectrometry (GC-MS). The risk Quotient (RQ) method was adopted for ecological risk assessments by using fish, daphnia, and algae as indicators. The concentration of OCPs ranged from 10.11 to 125.65 μg/kg and 10.96–45.17 μg/kg in Lake Tana and Hayqe, respectively. There was a statistically significant difference in the mean concentration of OCPs across the sampling sites in Lake Tana. Deltamethrin and lindane exhibit comparatively lower concentrations among the OCPs, whereas endrin, DDT, and their metabolites were the predominant pesticides in the study area, exceeding WHO and USEPA residue limits, except for endosulfan. Risk Quotient values ranged from 0.006 to 865.4 in Lake Tana and 0.005 to 729.9 in Lake Hayqe, indicating potential low to high ecological risks for aquatic organisms. High ecological risks are particularly evident in fish, daphnia, and algae species exposed to α and β-Endosulfan, DDT, and their metabolites, while specifically in daphnia, endrin poses high ecological risks. The ANOVA test revealed there were statistically significant differences (p-value <0.05) among sampling sites in Lake Tana and the mean values between Lake Tana and Lake Hayqe, underscoring the importance of addressing pesticide-related ecological concerns in the region.

Enhancing the Biosorption Potential of Pichia kluyveri FM012 for 4-Bromophenols

AbstractThe use of toxic and persistent pesticides in agriculture results in serious and lasting environmental impacts. Although traditional methods, such as physical and chemical reclamation, yield the best results, treating these contaminants requires a high cost and expertise. Therefore, this study focuses on bioremediation recovery, which is more efficient, economical, and safer for removal. In this case, the newly isolated potential of Pichia kluyveri FM012 in degrading 4-bromophenol was investigated. The impact of optimized parameters such as agitation, pH, nitrogen, and carbon source were also studied. After extensive testing, the best optimal degradation occurred at pH 5 with a stirrer speed of 150 rpm. Glucose and yeast performed the best compared to other carbon and nitrogen sources. The Langmuir model predicted the maximum biosorption capacity (qm = 38.46 mg/g biomass), but the Freundlich model provided a better value of R2 = 0.999. The pseudo-second-order kinetic model was fitting for the study of biosorption kinetics. The FTIR spectrum revealed the presence of asymmetric and symmetric vibrations of the aromatic ring and was assigned to C = C or C = O. Fungi showed biosorption ability across broad functional groups. These results provide interesting information about the ability of Pichia kluyveri FM012 and its potential applications for remediating resistant pesticides.

In situ single iron atom doping on Bi2WO6 monolayers triggers efficient photo-fenton reaction

Developing an efficient photocatalytic system for hydrogen peroxide (H2O2) activation in Fenton-like processes holds significant promise for advancing water purification technologies. However, challenges such as high carrier recombination rates, limited active sites, and suboptimal H2O2 activation efficiency impede optimal performance. Here we show that single-iron-atom dispersed Bi2WO6 monolayers (SIAD-BWOM), designed through a facile hydrothermal approach, can offer abundant active sites for H2O2 activation. The SIAD-BWOM catalyst demonstrates superior photo-Fenton degradation capabilities, particularly for the persistent pesticide dinotefuran (DNF), showcasing its potential in addressing recalcitrant organic pollutants. We reveal that the incorporation of iron atoms in place of tungsten within the electron-rich [WO4]2− layers significantly facilitates electron transfer processes and boosts the Fe(II)/Fe(III) cycle efficiency. Complementary experimental investigations and theoretical analyses further elucidate how the atomically dispersed iron induces lattice strain in the Bi2WO6 monolayer, thereby modulating the d-band center of iron to improve H2O2 adsorption and activation. Our research provides a practical framework for developing advanced photo-Fenton catalysts, which can be used to treat emerging and refractory organic pollutants more effectively.

Наукове обґрунтування медико-санітарного нормативу у ґрунті нових стійких пестицидів – представників різних хімічних класів

The aim: scientific substantiation of the medical-sanitary regulations is the maximum permissible concentration in soil of modern persistent pesticides: amicarbazone from the class of triazolones, bicyclopyrone from the class of triketones and pydiflumetofen from the class of pyrazolecarboxamides. Materials and methods. Three stages of research were carried out: mathematical modeling of amicarbazone, bicyclopyrone and pydiflumetofen migration from soil to adjacent environments; laboratory hygienic experiment to examine studied substances behavior in systems «soil – plants», «soil - atmospheric air» and substantiation of their threshold concentrations in soil according to the translocation, air-migration and water-migration indicators of harmfulness; impact study of amicarbazone, bicyclopyrone and pydiflumetofen on the nitrifying activity of leached chernozem and setting their threshold concentrations according to the general sanitary indicator of harmfulness. Results. It was experimentally established that the threshold concentrations in soil according to the water-migration indicator of harmfulness are the concentrations of amicarbazone, bicyclopyrone and pydiflumetofen of 0.02 mg/kg, 0.01 mg/kg, and 0.06 mg/kg, respectively. The calculated threshold concentrations of amicarbazone (0.05 mg/kg), bicyclopyrone (0.02 mg/kg) and pydiflumetofen (0.05 mg/kg), which were obtained by mathematical modeling, turned out to be very close to experimentally determined ones, which proves a rather high prognostic ability of the applied calculation method. The threshold concentration in soil of amicarbazone, bicyclopyrone and pydiflumetofen according to the water-migration indicator of harmfulness turned out to be the lowest compared to the threshold concentrations according to the translocation (0.2 mg/kg, 0.25 mg/kg and 0.12 mg/kg, respectively), air-migration (0.05 mg/kg, 1.0 mg/kg and 1.2 mg/kg, respectively) and general sanitary (0.2 mg/kg, 0.05 mg/kg and in the range 0.12-0.6 mg/kg, respectively) indicators of harmfulness. Therefore, the leading link of studied substance migration in the environment is the «soil – groundwater» system. Conclusions. The MPC of amicarbazone, bicyclopyrone and pydiflumetofen in soil is scientifically justified at the level of 0.02 mg/kg, 0.01 mg/kg and 0.06 mg/kg, respectively, according to the limiting water-migration indicator of harmfulness. Based on the studied substances in the recommended consumption rates and frequency of treatments the usage of plant protection products in the cultivation of agricultural crops will not lead to dangerous to human health contamination of groundwater, agricultural raw materials and atmospheric air, it will not cause a violation of the processes of self-cleaning of soil from nitrogen-containing organic substances in real soil-climatic conditions in Ukraine.

Widespread Pesticide Distribution in the European Atmosphere Questions their Degradability in Air.

Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricultural application season. Overall, 58 pesticides were observed in the European atmosphere. Low spatial variation of 7 pesticides suggests continental-scale atmospheric dispersal. Based on concentrations in free tropospheric air and at Arctic sites, 22 pesticides were identified to be prone to long-range atmospheric transport, which included 15 substances approved for agricultural use in Europe and 7 banned ones. Comparison between concentrations at remote sites and those found at pesticide source areas suggests long atmospheric lifetimes of atrazine, cyprodinil, spiroxamine, tebuconazole, terbuthylazine, and thiacloprid. In general, our findings suggest that atmospheric transport and persistence of pesticides have been underestimated and that their risk assessment needs to be improved.

Engineering Electrode Polarity for Enhancing In Situ Generation of Hydroxyl Radicals Using Granular Activated Carbon.

Recently, granular activated carbon (GAC) has shown its effectiveness as a cathode material for in situ ROS generation. Here, we present an electrochemically modified GAC cathode using electrode polarity reversal (PR) approach for enhanced H2O2 decomposition via 2-electron oxygen reduction reaction (2e-ORR). The successful GAC modification using PR necessitates tuning of the operational parameters such as frequency, current, and time intervals between the PR cycles. This modification enhances the GAC hydrophilicity by increasing the density of surface oxygen functionalities. After optimization of the electrode polarity, using the 20 (No PR)-2 (PR) interval and 140 mA current intensity, the •OH concentration reaches 38.9 μM compared to the control (No PR) (28.14 μM). Subsequently, we evaluated the enhanced •OH generation for the removal of glyphosate, a persistent pesticide used as a model contaminant. The modified GAC using PR removed 67.6% of glyphosate compared to 40.6% by the unmodified GAC without PR, respectively. The findings from this study will advance the utilization of GAC for in situ ROS synthesis, which will have direct implications on increasing the effectiveness of electrochemical water treatment systems.