Pesticide Retention Research Articles

Reconfiguring Alginate-Based Supra-amphiphiles via Redox-Responsive Pickering Emulsions for Enhancing Pesticide Droplet Retention.

In view of the micro/nanostructure tunability of colloid particles, they acted as agrichemical delivery systems. Herein, supra-amphiphilic colloids were fabricated using a host-guest interfacial recognition-architected emulsion template strategy and controlled their agricultural interfacial interactions with the superhydrophobic target surface. Interestingly, the supramolecular interfacial system possessed redox-stimulated molecular reconfigurability by regulating aggregation/disaggregation behaviors. Therefore, the surface roughness of silver willow-like supramolecular colloids was readily modulated by tuning the micro/nanointerfaces of the emulsion template, which exhibited a topology and pliability that allowed them to adapt to the micro/nanostructures of leaf surfaces. It simultaneously solved comprehensive problems of adhesion, bounding, and rainwashing of pesticide droplets by the multiscale coupling effect. Intriguingly, the pesticide retention dominantly depended on the degree of surface roughness of silver willow-like supramolecular colloids, and the most roughened one showed greatest in vitro antifungal efficiency against Botrytis cinerea, reaching 91.8% even through multiple rainwashing. Results disclosed that the supra-amphiphilic colloids addressed the entire application processes for promoting the development of sustainable agricultural science.

Chitin nanocrystal Pickering emulsions for sustainable release pesticide microencapsulation with superior leaf adhesion and enhanced safety

Traditional pesticides often exhibit high non-target toxicity, poor stability, short persistence, and susceptibility to wash-off by rain. Pesticide microencapsulation represents a significant advancement in formulation strategies, addressing safety and sustainability concerns associated with conventional pesticides. This study explores the utilization of biodegradable chitin nanocrystals (ChNCs), prepared via acid hydrolysis, for the development of pesticide microcapsules. Specifically, ChNCs were employed to emulsify molten pesticides, followed by interfacial polymerization to fabricate pesticide-loaded microcapsules. Using molten emulsification and Pickering emulsion templates offer a simple and solvent-free approach for microcapsule preparation, eliminating the need for conventional surfactants. The microcapsules displayed a size distribution ranging from hundreds of nanometers to several micrometers, which could be tuned by adjusting the ChNCs content. These microcapsules demonstrated remarkable properties, including a high pesticide loading capacity (reaching 78.7% for lambda-cyhalothrin), excellent storage stability, and enzyme-responsive release behavior. Furthermore, the abundant positive charges enhanced the interaction between the microcapsules and leaf surfaces, leading to improved pesticide retention. Microencapsulation reduces acute insecticidal activity of pesticides due to the slow-release effect; however, field experiments provide compelling evidence that microcapsule formulations significantly prolong pesticide efficacy compared to conventional formulations. Additionally, microencapsulation significantly improved the safety of pesticides, with the LC50 increasing from 0.0116 mg/L to 3.75 mg/L. Overall, this study introduces a promising method for pesticide microencapsulation using ChNCs Pickering emulsion, highlighting its potential advantages and providing valuable insights for the development of environmentally friendly and novel pesticide formulations.

Enhanced retention of hydrophobic pesticides in subsurface soils using organic amendments

The rapid global population growth since the early 2000s has significantly increased the demand for agricultural products, leading to widespread pesticide use, particularly organophosphorus pesticides (OPPs). This extensive application poses severe environmental risks by contaminating air, soil, and water resources. To protect groundwater quality, it is crucial to understand the transport and fate of these pesticides in soil and sediment. This study investigates the effects of hydrochars and biochars derived from sugar beet shreds (SBS) and Miscanthus×giganteus (MIS) on the retardation and biodegradation of OPPs in alluvial Danube sandy soil. The research is novel in its approach, isolating native OPP-degrading bacteria from natural alluvial sandy soil, inoculating them onto chars, and reapplying these bioaugmented chars to the same soil to enhance biodegradation and reduce pesticide leaching. The amendment of chars with immobilized Bacillus megaterium BD5 significantly increased bacterial abundance and activity. Metabarcoding of the 16S rRNA gene revealed a dominance of Proteobacteria (48.0–84.8 %) and Firmicutes (8.3–35.6 %). Transport modeling showed retardation coefficients (Rd) for OPPs ranging from 10 to 350, with biodegradation rates varying between 0.05 % and 75 %, indicating a positive correlation between retardation and biodegradation. The detection of biodegradation byproducts, including derivatives of phosphin, pyridine, and pyrazole, in the column leachate confirmed that biodegradation had occurred. Additionally, principal component analysis (PCA) revealed positive correlations among retardation, biodegradation, specific surface area (SSA), aldehyde/ketone groups, and bacterial count. These findings demonstrate the potential of biochar and hydrochar amendments to enhance OPP immobilization in contaminated soils, thereby reducing their leaching into groundwater. This study offers a comprehensive approach to the remediation of pesticide-contaminated soils, advancing both our fundamental understanding and the practical applications of environmental remediation techniques.

Polydopamine-coated matchstick-like mesoporous silica carriers for improving foliar retention and responsive pesticide release

Intelligent responsive pesticide delivery systems have gained extensive interest in enhancing utilization efficiency of pesticides and relieving environmental hazards. Herein, we developed a novel matchstick-like mesoporous silica (mSiO2) nanocarriers for pesticide delivery. The asymmetric matchstick-like mSiO2 carriers were composed by a spherical dendritic silica (SiO2) head (300 nm) and a rod-shaped tail (90 nm in length). This asymmetric structure would improve foliar retention by increasing contact area and forming topological effect between the carriers and the leaves surface. The prepared mSiO2 carriers possessed a high loading content for the insecticide dinotefuran (DNF) (23.7 %). Subsequently, polydopamine (PDA) was utilized to seal the DNF-loaded mSiO2 (DNF@mSiO2@PDA). The foliar affinity and adhesion properties of the mSiO2@PDA were enhanced due to the introduction of the hydrophilic PDA layer. The DNF@mSiO2@PDA exhibited pH-responsive release performance and the anti-UV property of loaded DNF was improved by about 10 times. Additionally, the DNF@mSiO2@PDA also exhibited high insecticidal activity due to the improving foliar wetting and affinity. Therefore, this work provides a promising strategy to increase pesticide retention on leaves and reduce pesticide chemical usage.

Pedological factors affecting pesticide retention in a series of tropical volcanic ash soils in the French West Indies

Specific pedoclimatic conditions in tropical environments have a considerable impact on pesticide fate. Tropical volcanic soils result from specific pedogenesis processes linked to successive volcanic projections; they are characterised by acidic conditions, high organic matter content, a specific mineralogical composition and the presence of organo-mineral complexes. The retention of pesticides in these soils is therefore often high but variable depending on the associated molecules and soil properties. Nevertheless, knowledge of pesticide sorption in these soils remains limited, and knowledge of the desorption process is scarce. The objectives of this work were to study the variability of the sorption and desorption coefficient of four pesticides currently used in banana and sugarcane crops on a set of representative tropical soils developed on volcanic ash (Guadeloupe, French West Indies). Adsorption and desorption isotherms were analysed for three ionizable pesticides (2,4-D, mesotrione, glyphosate) and a hydrophobic pesticide (difenoconazole) on ten soil samples from five soil profiles: one silandic andosol, one vitric andosol, two nitisols and one ferralsol. For ionizable pesticides, soil pH appears to be a first-order discriminating factor of the sorption capacity, and the organic carbon content appears to have a lesser impact on 2,4-D. For a strongly hydrophobic pesticides such as difenoconazole, the organic carbon content plays a major role in sorption. Desorption hysteresis has been observed regardless of the soils and the molecules considered, and tropical volcanic soils seem to be conducive to adsorption but show low to moderate release. The silandic andosol, which has the greatest sorption, buffers the dissemination of pesticides towards surface and groundwaters but also increases the risk of long-term contamination in the case of molecules that degrade slowly. Moreover, our results highlight that agronomic practices, such as liming, have a major impact on the sorption coefficient of pesticides and must be considered for when predicting sorption in a tropical volcanic context.

Sea urchin-like nanocarrier for enhancing pesticide retention and rain fastness on hydrophobic and hydrophilic crop foliage

Foliar washoff by rainfall is a major factor inducing the inefficient utilization of pesticides. Enhancing the adhesion and retention of pesticide on plant foliage has long been of interest. The presence of waxy platelets on most plant foliage surfaces renders them rough and hydrophobic. This reduces the area of contact between pesticide particle and plant foliage, which decreases the adhesion. In this study, we developed a pesticide nanocarrier (PANI/HACC) with sea urchin-like surface morphology based on polyaniline (PANI) doped with biodegradable 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC). Then, azoxystrobin (AZOX) loaded nanoparticles (AZOX@PANI/HACC) was synthesized by physical adsorption. It exhibited retention rates of 61.4% on rice leaves and 64.6% on cucumber leaves, which were higher than that of commercially available azoxystrobin water dispersible granules (AZOX-WDG, 42.1% and 24.5%, respectively) and suspension concentrates (AZOX-SC, 23.1% and 58.8%, respectively). Additionally, pot experiments demonstrated that the control efficacy of AZOX@PANI/HACC on rice against Rhizoctonia solani was 1.64-fold and 3.0-fold of that of AZOX-WDG and AZOX-SC, respectively. The higher retention performance of AZOX@PANI/HACC was attributed to the stable adhesion by fitting nanometer-sized spikes into the spaces between the waxy platelets. Overall, the pesticide nanocarrier with spiky surface morphology provides an effective strategy for improving pesticide retention and reducing pesticide loss in agricultural production.

Analysis of carbamate and organophosphorus pesticide in agricultural irrigation water by Liquid Chromatography - Mass Spectrometry

So far, the ultra-trace concentration of pesticide residues in environmental samples has challenged many analytical techniques, which are used to detect simultaneously organophosphorus and carbamate with various polarities. In this study, the OASIS-HLB column was modified by the reagent 1,8-Dihydroxy-2-(4-sulfophenylazo)naphthalene-3,6-disulfonic to enhance the retention of polar pesticides. Both real irrigation water and distilled water samples were applied to validate the determination method of ten carbamates and thirty-eight organophosphorus pesticides all together using LC-MS. According to the results, the linear interval of the method ranged from 1.0 to 100 µg/L, the detection limit was as low as 5.0 µg/L, the relative standard deviations presented less than 8.0%, and the recoveries were ranging between 60% and 112%. Moreover, in the irrigation water samples which were collected in both dry and rainy seasons in ten stations around the agricultural area, five compounds were found, including fenamiphos, terbufos, aldicarb, propoxur, and methiocarb. In the midst of those sampling areas, the Environmental Impact Quotient Field Use Rating of detected pesticide residues presented a high value - 272 at one station, which indicates a high risk for the surrounding environment as well as the local people’s health.

Quaternized chitosan-based organic-inorganic nanohybrid nanoparticles loaded with prothioconazole for efficient management of fungal diseases with minimal environmental impact

Poor foliar deposition and retention of pesticides results in serious pesticide residues and environmental pollution. Organic-inorganic hybridized nanoparticles (OIHN), combining the advantages of organic and inorganic materials, can be used as carriers to load pesticides for efficient and safe application. Herein, a novel multifunctional OIHN composed of mesoporous silica nanoparticles (MSNs) and cationic chitosan quaternary ammonium salt (HACC) was constructed and used as a delivery system for prothioconazole (PTC). The resultant PTC@MSNs-HACC exhibited a remarkable loading capacity of 39.07 wt% and demonstrated enhanced PTC release (31.47 %) under alkaline conditions. The UV-shielding properties of MSNs efficiently shielded PTC from photodegradation, increasing its photostability by over threefold. The strong positive charge of HACC conferred excellent adhesion of PTC@MSNs-HACC to fungal cell membranes, leading to high deposition on wheat leaves with improved rain-wash resistance (increased by 30 %). Consequently, PTC@MSNs-HACC (EC50: 12.48 mg/L) exhibited superior wheat scab control compared to PTC emulsifiable concentrate (EC50: 28.49 mg/L). Additionally, PTC@MSNs-HACC displayed excellent uptake and transport in plants, ensuring plant safety and reducing toxicity to zebrafish by >1-fold. The potential application of the developed PTC@MSNs-HACC in agricultural production holds significant promise and is anticipated to find widespread use in the future.

Multi-bioinspired alginate-based gel coatings formed by dynamic metal–ligand assembly for enhancing foliar affinity and rain-fastness of pesticides

Insufficient deposition of pesticide droplets and rain erosion are significant factors in excessive pesticide wastage and pose a significant threat to public health and the ecological environment. Inspired by the adhesion mechanism of marine mussels and mayfly larvae, we developed a gel coating to improve pesticide retention efficiency and resistance to rainwater washout by sequential spraying polydopamine-functionalized alginate and Fe3+ ions onto the target leaf surface (SA-DA/Fe3+). Abundant catechol groups provide strong molecular-level interfacial bridging for alginate derivates, while the gel coating contains flexible, deformable, and complex nanoscale networks, inducing mutual coupling with micro/nanostructures on the leaf surface, ultimately resulting in the removal of the interface void and the improvement of deposition capacity at multiple scales. The gel coating shows high cohesive energy to better resist rain rinsing due to the dense carboxyl-Fe3+ and catechol-Fe3+ coordination bonds in the network architecture. By combining the above effects, the pesticide retention rate of SA-DA/Fe3+ gel coating on foliage could reach about 97 % after rain erosion and immersion. In addition, the SA-DA/Fe3+ gel coating can also achieve the sensitive photo-control effect of pesticides due to the intrinsic photosensitivity of the iron-carboxylate system. Using an alginate-based gel coating as a promising strategy for improving pesticide utilization, addressing the issues of easy runoff, susceptibility to erosion, and uneven coverage in traditional pesticide droplet form, thus bridging the fields of bionic materials science, bio-macromolecular chemistry, and agricultural science.

Multifunctional hollow silica carriers with spiny structure for enhanced foliar adhesion and triple-responsive pesticide delivery

Intelligent responsive pesticide formulations hold great promise for enhancing foliage retention and effective utilization. Herein, hollow silica (S-HS) nanocarriers with spiny structure were constructed for pesticide delivery. The S-HS nanocarriers presented homogeneous spiny spheres with an average size of 220 nm. This spiny structure can achieve effective retention on foliage by the “hanger-hat” topology effect. For constructing the responsive layer, the S-HS nanocarriers were further functionalized with surface vinyl groups. After loading imidacloprid (IMI), the temperature sensitive poly N-isopropylacrylamide (pNIPAm) and tannic acid–Fe complexes (TA-Fe) were introduced to encapsulate pesticides (IMI@S-HS-pNT). The TA-Fe complex layer served as a wall material and photothermal agent. The S-HS-pNT carriers achieved a loading capacity for IMI (26.6 %), high photothermal conversion effect (η = 36.1 %), and good biocompatibility. Except for excellent photostability and foliar adhesion property, the IMI@S-HS-pNT exhibited pH, temperature and near infrared (NIR) responsive release behavior. Moreover, the S-HS nanocarriers could be effectively transported to various parts of tobacco plants under the root immerse or foliar spray. The IMI@S-HS-pNT showed the high control efficacy against Plutella xylostella. Overall, this work provides insight into improving the efficiency of utilization and prolonging pesticide retention on plant leaves.

Environmental fate of chlorpyrifos in Rhodic Ferralsol grown with corn during summer and winter seasons under high-intensity rainfall

The interactions between pesticides' physicochemical properties and edaphoclimatic factors influence their distribution into the environment. Understanding how those factors interact in a changing environment is crucial for mitigating environmental and agronomic problems. Thus, a percolation lysimeter with undisturbed soil and suction lysimeters were used to conduct a field study to evaluate the distribution of chlorpyrifos sprayed in a corn crop cultivated in a Rhodic Ferralsol in simulated extreme rainfall conditions. The mobility of chlorpyrifos was evaluated under simulated precipitation (150 mm h−1), 24 h and 48 h after applying the chlorpyrifos in different phenological stages of corn during the summer and winter crops in two agricultural years. In addition, GC-ECD determined the residual concentration of chlorpyrifos in the runoff and leached samples. Finally, a laboratory adsorption study was conducted with Rhodic Ferralsol to find the chlorpyrifos adsorption capacity in different temperatures, with and without soil organic matter. Our results show that soil organic matter is essential in chlorpyrifos adsorption, responsible for approximately 5% pesticide retention, which could be 25% higher during winter. High-intensity rainfalls positively affect runoff and leaching; nevertheless, these are responsible for only 0.2% of all chlorpyrifos amounts, as the soil is the major reservoir of chlorpyrifos by retention into clays and organic matter. Furthermore, the corn growth stages directly affect chlorpyrifos transportation, with higher amounts observed in runoff and leaching during the first and last corn growth stages. Therefore, in the conditions such as high-intensity rainfall, exposed soil, shallow soil profile, and temperatures below 20 °C, attention should be paid to chlorpyrifos spray with special regard to the weather forecast, avoiding its spray near rainfall events. Further studies should be conducted in other soil classes and rainfall conditions to validate our observations.

Biobeds, a Microbial-Based Remediation System for the Effective Treatment of Pesticide Residues in Agriculture

Pesticides are chemical molecules employed to protect crops from pests in agriculture. The use of pesticides significantly enhances crop yields and helps to guarantee the quality of farm products; due to this, each year, millions of tons of pesticides are employed in crop fields worldwide. However, the extensive use of pesticides has been related to environmental pollution, mainly in soils and water bodies. The presence of pesticides in the environment constitutes a menace to biodiversity, soil fertility, food supply, and human health. Activities related to pesticide use in crops, such as the handling and pesticide dissolution before application, the filling and cleaning of aspersion equipment and machinery, accidental spills in crop fields, and the inadequate disposal of pesticide residues have been identified as important punctual pesticide pollution sources. Therefore, avoiding releasing pesticide residues into the soil and water is crucial to mitigating the environmental pollution associated with agricultural practices. Biobeds are biological systems that have been proposed as feasible, low-cost, and efficient alternatives for punctual pesticide pollution mitigation. Biobeds were first described as trenches packed with a mixture of 50% wheat straw, 25% soil, and 25% peat, covered with a grass layer; this composition is known as a “biomixture”. In biobeds, the biomixture absorbs the pesticide residues and supports the development of different microorganisms, such as bacteria and fungi, needed for pesticide degradation in the system. The effectiveness of a biobed systems lies in the high pesticide retention in the biomixture and the degradation potential of the microorganisms growing in the system. In this review, 24 studies published in the last five years (2018–2022) related to pesticide biodegradation in biobed systems are analyzed, emphasizing alternative biomixture composition usage, microbiological strategies, and the key physicochemical parameters for efficient pesticide degradation in the biobed systems. The availability of robust scientific evidence about the simple applicability, low cost, and effectiveness of biobeds for pesticide residue treatment is crucial to increasing the use of biobeds by farmers in different agricultural regions around the world.

PITCH: A model simulating the transfer and retention of pesticides in infiltrating ditches and channel networks for management design purposes

Agricultural ditches are frequently included in the panel of landscape elements to be managed to minimize the negative impacts of agriculture on the environment, particularly water contamination. A new mechanistic model simulating pesticide transfer in ditch networks during flood events was developed for help in designing ditch management. The model considers pesticide sorption processes to soil, living vegetation and litter and is adapted to heterogeneous and infiltrating tree-like ditch networks, with a reach resolution. The model was evaluated with pulse tracer experiments conducted on two vegetated and litter-rich ditches and with two contrasting pesticides, namely, diuron and diflufenican. It appears necessary to consider exchange of only a small proportion of the water column with the ditch materials to achieve a good reproduction of the chemogram. The model simulates well the chemogram of diuron and diflufenican during calibration and validation (with Nash performance criteria values ranging from 0.74 to 0.99). The calibrated thicknesses of the soil and water layers contributing to the sorption equilibrium were very small. The former was intermediate between the theoretical transport distance by diffusion and the thicknesses usually considered in mixing models for pesticide remobilization by field runoff. The numerical exploration of PITCH showed that during flood events, retention in ditches is mainly due to adsorption of the compound by the soil and litter. Retention is thus driven by the corresponding sorption coefficients and by parameters controlling the mass of these sorbents such as ditch width and litter cover. The latter parameters can be modified by management practices. In some cases, infiltration can contribute significantly to pesticide removal from surface water and in return participate in soil and groundwater contamination. Finally, PITCH exhibits a consistent behaviour in predicting pesticide attenuation and is shown to be relevant for evaluating ditch management strategies.

An environmentally benign oil dispersion/phytoextract system for improved retention upon foliage and control of aphids in spice crops

About one-third of agricultural production relies upon chemical pesticides. The major part of applied pesticides is lost due to poor retention characteristics, whereas the retention is related to pesticide utilization efficiency. The drift pesticides create substantial environmental contamination and are a primary concern because of their high persistence and toxicity to humans and non-targets. Coupling bio-pesticide and suitable delivery systems to optimize targeting and uptake will enable the design of suitable agrochemicals that combine optimal safety, sustainability, and functionality profiles. We present a strategy to address the issue by taking advantage of oil dispersion (OD) as a delivery system for loading leaf phyto-extract of an indigenous plant (Dalbergia sissoo). The chemical profiling of phyto-extract performed by GC-MS revealed the presence of hydrocarbons, fatty acid methyl esters, and their derivatives, including majorly Glycidyl oleate, Cinnamyl linoleate, whereas LC-MS analysis briefed the presence of compounds; Ferulic acid and a chalcone flavonoid- Isoliquiritigenin. The OD was developed via a two-step process; dispersion followed by wet grinding, which displayed shear-thinning rheological behavior. Upon spraying on leaves, the OD carrier could achieve enhanced wetting and spreading on the foliage. Driven by the additive-based interactions, OD improved pesticide retention and wash resistance, which was evident by the fluorescent labelling of the formulation. The leaf extract-loaded OD possesses a 9-day residual effect and excellent efficacy in controlling Aphids, comparable to synthetic insecticide. Overall, OD-loaded phyto-extract provides an effective strategy for prolonging pesticide retention and reducing pesticide loss in agro-production, both of which are desirable for a cleaner and pollution-free environment.

Achieving High Efficacy and Low Safety Risk by Balancing Pesticide Deposition on Leaves and Fruits of Chinese Wolfberry (Lycium barbarum L.).

Pesticide residue has become the main technical barrier that restricts the export of Chinese wolfberry. Can we achieve high efficacy and low safety risk by balancing pesticide deposition on the leaves and fruits of Chinese wolfberry? In this research, the structural characteristics and wettability of leaves and fruits of Chinese wolfberry at different growth stages were studied. The adaxial and abaxial surfaces of leaves were hydrophobic, whereas the fruit surfaces were hydrophilic. Adding spray adjuvant could increase the retention of droplets on the leaf surfaces of Chinese wolfberry by 52.28-97.89% and reduce the retention on the fruit surfaces by 21.68-42.14%. A structural equation model analysis showed that the adhesion tension was the key factor affecting the retention of the solutions among various interface behaviors. When the concentrations of Silwet618, AEO-5, Gemini 31551, and 1227 were 2-5 times higher than their CMCs, the retention of pesticide solutions (pyraclostrobin and tylophorine) on Chinese wolfberry leaves significantly increased, and the control efficacies on aphids and powdery mildew also dramatically improved (65.90-105.15 and 41.18-133.06%, respectively). Meanwhile, the retention of pesticides on the fruit of Chinese wolfberry was reduced. This study provides new insights into increasing the utilization of pesticides in controlling pests and improving food safety.

Polydopamine-encapsulated cap-like mesoporous silica based delivery system for responsive pesticide release and high retention

Nanopesticides formulation has been applied in modern agriculture, but the effective deposition of pesticides on plant surfaces is still a critical challenge. Here, we developed a cap-like mesoporous silica (C-mSiO2) carrier for pesticide delivery. The C-mSiO2 carriers with surface amino groups present uniform cap-like shape and have an mean diameter of 300 nm and width of 100 nm. This structure would reduce the rolling and bouncing of carriers on plant leaves, leading to improving the foliage deposition and retention. After loading dinotefuran (DIN), polydopamine (PDA) was used to encapsulate the pesticide (DIN@C-mSiO2@PDA). The C-mSiO2 carriers exhibit high drug loading efficiency (24.7%) and benign biocompatibility on bacteria and seed. Except for pH/NIR response release, the DIN@C-mSiO2@PDA exhibited excellent photostability under UV irradiation. Moreover, the insecticidal activity of DIN@C-mSiO2@PDA was comparable to that of pure DIN and DIN commercial suspension (CS-DIN). This carrier system has the potential for improving the foliage retention and utilization of pesticides.

Polymeric membranes functionalized with nanomaterials (MP@NMs): A review of advances in pesticide removal

The excessive contamination of drinking water sources by pesticides has a pernicious impact on human health and the environment since only 0.1% of pesticides is utilized effectively to control the and the rest is deposited in the environment. Filtration by polymeric membranes has become a promising technique to deal with this problem; however, the scientific community, in the need to find better pesticide retention results, has begun to meddle in the functionalization of polymeric membranes. Given the great variety of membrane, polymer, and nanomaterial synthesis methods present in the market, the possibilities of obtaining membranes that adjust to different variables and characteristics related to a certain pesticide are relatively extensive, so it is expected that this technology will represent one of the main pesticide removal strategies in the future. In this direction, this review focused on, - the main characteristics of the nanomaterials and their impact on pristine polymeric membranes; - the removal performance of functionalized membranes; and - the main mechanisms by which membranes can retain pesticides. Based on these insights, the functionalized polymeric membranes can be considered as a promising technology in the removal of pesticides since the removal performance of this technology against pesticide showed a significant increase. Obtaining membranes that adjust to different variables and characteristics related to a certain pesticide are relatively extensive, so it is expected that functionalized membrane technology will represent one of the main pesticide removal strategies in the future.

Distribution of pesticide residues in agricultural topsoil of the Huangshui catchment, Qinghai Tibet Plateau.

This study presents monitoring data on the spatial distribution and occurrence of pesticide residues of cultivated soil in the Huangshui catchment in the northeastern part of the Qinghai Tibet Plateau. We also provide factors that influence the distribution of pesticides, such as the properties of pesticides and soil and crop types. A total of 110 soil samples were collected in early April 2021, and 49 pesticides were analyzed. Only 3.6% of the samples contained no pesticide residues (concentrations < limit of quantitation or not detected [ND]), and the total pesticide concentration ranged from ND to 0.925mg/kg. Most commonly, two to five pesticides were found in the soil samples (> 70.9%), and up to 10 pesticide residues were present in some samples. A total of 85 different pesticide combinations were observed in all the soil samples. Chlorpyrifos and difenoconazole were the dominant compounds. The levels of pesticide residues were mainly driven by their half-life values. Bulk density, along with soil water content and pH, also affected the retention of pesticides in the soil. The crop type played no role in the distribution of pesticides.

Bio-based mesh-like pesticide carriers via copper ions chelation for prolonging pesticide retention and flush resistance on foliage

In the past few years, the development of smart pesticide-controlled release systems has emerged as an important strategy in modern precision agriculture, particularly to increase retention efficiency and improve the utilization of pesticides. In order to achieve effective retention of pesticide spraying formulations on foliage surfaces, the present study aimed to develop a novel bio‐based mesh‐like pesticide carrier (named PDA/HDA‐Cu/MEP@CNC), using polydopamine (PDA) and hexadecylamine (HDA) -coated cellulose nanocrystal (CNC), wherein copper ion was used for chelation. Fenitrothion (MEP) was used as a model pesticide in the study. The use of PDA/HDA‐Cu/MEP@CNC exhibited sustained stimuli‐response release behavior under an alkaline environment, which was attributed to the coordination of copper ions on CNC. The deposition efficiency of the prepared PDA/HDA‐Cu/MEP@CNC was enhanced owing to the presence of the PDA layer. In addition to this, the use of PDA/HDA‐Cu/MEP@CNC resulted in more than 75% enhancement in the antifungal activity towards Rhizoctoni solani (R.s.), as compared to commercial MEP. Further, the results for biosafety assessment demonstrated that the prepared pesticide carrier exhibited remarkable biosafety properties. Altogether, enhanced retention property, controlled release behavior, and biosafety activity of this modified nanocellulose based controlled release system highlighted its potential to be explored as a commercial formulation for pesticide spraying.

Gain and retain - On the efficiency of modified agricultural drainage ponds for pesticide retention

Drainage ponds have the potential to serve as long-term interface measures primarily for flood control, and mass retention. They are often considered as promising supplements for the mitigation of drainage pipe loads to improve the water quality in agricultural landscapes. In this study, a highly dynamic drainage pond system with non-steady inflows and groundwater interaction was modified and investigated regarding its potential for pesticide and transformation product (TP) retention. For this purpose, two 104-day monitoring campaigns were conducted before and after pond modification. Field experiments with fluorescent tracers, Uranine and Sulforhodamine-B, proved that structural modifications improved the hydraulic functionality of the ponds. The effective volume (Ɛ) increased from 20% to almost 100% in the modified pond and the mean hydraulic residence time (τ) was ten times longer. After a dry period, pesticide retention was high during slow refilling of the ponds, still TP loads posed a risk by infiltration into shallow groundwater due to the permeable ground. During wet periods, short nominal detention times together with high inflows led to rare high retention rates through peak attenuation. Moderate inflows resulted in extremely variable retention values, owing to the small pond storage capacity. Along with this, the total retention efficiency after modification reached up to 38% for mobile, 29% for sorptive pesticides, and 32% for mobile TPs. To achieve the best performances for ponds as natural landscape elements, they should be analysed for their hydrological functionality as a prerequisite and then modified for delayed pesticide and TP transport. Then, dynamic drainage ponds can utilize their full potential regarding mitigation of pesticide and TP loads in agricultural catchments.