Phytoremediation of azoxystrobin and its degradation products in soil by P. major L. under cold and salinity stress

1-Tetradecanol, Diethyl Phthalate and Tween 80 Assist in the Formation of Thermo-Responsive Azoxystrobin Nanoparticles

The occurrence of crop fungal diseases is closely related to warm environmental conditions. In order to control the release of fungicides in response to warm conditions, and enhance the efficacy, a series of thermo-responsive fungicide-loaded nanoparticles were developed. The fungicide azoxystrobin, solvent DEP, emulsifier Tween 80 and thermo-responsive component TDA were combined to create thermal-response oil phases, conditions for emulsification were then optimized. LDLS, zeta potential, FTIR, DSC, TGA, XRD, SEM and antifungal efficacy assays were carried out to investigate the characteristics and forming mechanism. The results indicated that the formula with 5 g azoxystrobin, 10 mL DEP, 6 mL Tween 80 and 2.5 g TDA constructed the proposed oil phase with the ability to transform from solid at 20 °C to softerned at 31.5 °C. Both DEP and TDA played key roles in interfering with the crystallization of azoxystrobin. The optimal T3t-c12 nanoparticles had a mean particle size of 162.1 nm, thermo-responsive morphological transformation between 20 °C and 30 °C, AZO crystal reforming after drying, the ability to attach to fungal spores and satisfied antifungal efficacy against P. nicotiana PNgz07 and A. niger A1513 at 30 °C. This report provides referable technical support for the construction of smart-release nanoparticles of other agrochemicals.

Preparation of metal-organic framework @molecularly imprinted polymers for extracting strobilurin fungicides from agricultural products

The core-shell metal-organic framework coated with molecularly imprinted polymers (ZIF-8@MIPs) were successfully synthesized by surface imprinting technique, and applied as adsorbents for solid-phase extraction of strobilurin fungicides. The obtained hybrid complex was characterized in detail, and their adsorbing and recognition performance were evaluated. The results showed that ZIF-8@MIPs presented typically core-shell structure with MIP shell (about 20 nm), and exhibited larger adsorption capacity (102.5 mg g^-1) and fast adsorption ability (only 5 min). Under the optimized conditions, a sensitive, efficient and reliable method for determining six strobilurin fungicides in different agricultural products based on ZIF-8@MIPs coupling with high performance liquid chromatography-tandem mass spectrometry was established. This method showed good linearity with correlation coefficients higher than 0.9990. With spiked at three different concentration levels in agricultural products (apple, pear, banana, Chinese cabbage, cabbage, cucumber), the good recoveries (83.5-129.0%) with relative standard deviations from 0.5 to 10.2% were obtained. The limit of detections and the limit of quantifications were 0.01-1.12 ng g^-1 and 0.03-3.73 ng g^-1, respectively. Those results demonstrated good potential application of ZIF-8@MIPs for enriching and separating trace strobilurin fungicides in agricultural samples.

Effects of chloropicrin fumigation and azoxystrobin application on ginger growth and phosphorus uptake

Soil chloropicrin (CP) fumigation helps to increase crop yields by eliminating soil-borne diseases which inhibit plant growth. However, little is known about the effect of the CP fumigation combined with fungicide application on plant growth and nutrient uptake. In this study, we conducted a mesocosm experiment with six treatments: CK (untreated soil), AZO1 (a single application of azoxystrobin (AZO)), AZO2 (double applications of AZO), CP (CP fumigation with no AZO), CP+AZO1 (CP combined with AZO1) and CP+AZO2 (CP combined with AZO2) to investigate the effects of CP fumigation and AZO application on ginger growth and phosphorus (P) uptake. Results showed that a single application of AZO had no significant effect on ginger height, biomass and P uptake whether treated with or without CP fumigation, whereas double applications of AZO combined with CP fumigation significantly improved ginger height and the total amount of P in root (P < 0.05). Meanwhile, AZO residues were similar in all treatments with the same number of applications, with less than 50% remaining in the soil after 7 days applied, indicating that CP fumigation treatment did not influence AZO degradation in ginger cultivation. In addition, although the differences in P use efficiency observed across the different treatments were not significant, they nevertheless suggest that the P budget and soil microbial activity may contribute to those differences. Therefore, further studies should be done to link P cycling with microbial communities, and how these related to fumigation and fungicide application.

Supermagnetic Mn-substituted ZnFe2O4 with AB-site hybridization for the ultra-effective catalytic degradation of azoxystrobin

Magnetic Zn0.25Mn0.75Fe2O4 was applied to the degradation of azoxystrobin in a Fenton-like system, and the performance was enhanced via crystal structure control.

Phytoremediation of azoxystrobin and imidacloprid by wetland plant species Juncus effusus, Pontederia cordata and Sagittaria latifolia

Azoxystrobin (strobilurin fungicide) and imidacloprid (neonicotinoid insecticide) have been detected in surface waters near treated agricultural, urban, and mixed landscapes. The hazards of pesticide runoff can be prevented through best management practices, including the establishment of diverse wetland plant barriers that can phytoremediate the chemicals in which they come into contact with. In this study, the wetland plant species softrush (Juncus effusus), pickerelweed (Pontederia cordata), and arrowhead (Sagittaria latifolia) were planted in sandy soil containers that were then placed in azoxystrobin or imidacloprid treated water. Every week for 2 months, water samples were collected for pesticide residue analysis using high-performance liquid chromatography (HPLC). At 14, 28, and 56 days after initiation, plants were destructively harvested and analyzed for pesticide residue in soil, above-ground vegetation, and below-ground vegetation. Results from this study report P. cordata reduced greater azoxystrobin (51.7% reduction compared to treated non-planted containers) compared to J. effusus and S. latifolia (24.9% and 28.7% reduction from non-planted containers) at 56 days. However, S. latifolia reduced greater imidacloprid (79.3% reduction compared to non-planted containers) compared to J. effusus and P. cordata (36.0% and 37.1% reduction from non-planted containers) at 56 days.Novelty statement: While research has found that wetland plants can absorb and remediate synthetic chemicals, this practice is only sustainable if used with native plants that require low maintenance and are tolerant to the applied substances. Various previous studies observe plants that are fast-growing, tolerant to environmental conditions, require low-maintenance, and are hardy. However, these plant species are not always suitable for any location and are often considered invasive and/or weed-like. The present research initiates a list of plant species which can be used within the southeastern United States and similar areas to phytoremediate commonly used pesticides azoxystrobin and imidacloprid and prevent off-target movement into sensitive water systems.

Phytoremediation potential of three terrestrial plant species for removal of atrazine, azoxystrobin, and imidacloprid

Pesticides can move off-target resulting in contamination of sensitive water bodies and causing adverse effects on inhabiting species. Through best management practices, such as the implementation of vegetative buffer strips, off-target movement of pesticides can be decreased, and compound degradation can be increased via phytoremediation. In this study, blueflag iris (Iris versicolor), broomsedge (Andropogon virginicus) and switchgrass (Panicum virgatum) were planted in soil treated with one of three commonly used pesticides. At 28, 56 and 112 days after treatment (DAT), plants were destructively harvested and analyzed for pesticide residue in soil and above-ground and below-ground vegetation using high-performance liquid chromatography (HPLC). Relative to the amount of pesticide found in planted pots compared to non-planted pots, I. versicolor was found to reduce greater atrazine in soil compared to non-planted pots at 112 DAT by 58.7%. I. versicolor was also the most capable of reducing azoxystrobin, by 86.9% compared to non-planted pots, from the soil at 112 DAT. At the same sampling time, I. versicolor and P. virgatum reduced greater imidacloprid from soil by 62.5% and 64.3% compared to non-planted pots, respectively. This information supports the recommendation for establishment of diverse plant species for optimization of phytoremediation capacities. Novelty statement While research has found that plants can absorb and remediate synthetic chemicals, this practice is only sustainable if used with native plants that require low maintenance and are tolerant to the applied substances. Various previous studies observe plants that are fast-growing, tolerant to environmental conditions, require low-maintenance, and are hardy. However, these plant species are not always suitable for any location and are often considered invasive and/or weed-like. The present research initiates a list of plant species which can be used within the southeastern United States and similar areas to phytoremediate commonly used pesticides atrazine, azoxystrobin, and imidacloprid and prevent off-target movement.

Pesticides and their degradates in groundwater reflect past use and current management strategies, Long Island, New York, USA

Long Island, New York, has a mix of urban/suburban to agricultural/horticultural land use and nearly 3 million residents that rely on a sole-source aquifer for drinking water. The analysis of shallow groundwater (<40 m below land surface) collected from 54 monitoring wells across Long Island detected 53 pesticides or pesticide degradates. Maximum concentrations for individual pesticides or pesticide degradates ranged from 3 to 368,000 ng/L. The highest concentrations and most frequent pesticide detections occurred in samples collected from the pesticide management (PM) network, set in an agricultural/horticultural area in eastern Long Island with coordinated pesticide management by state and local agencies. The other two networks (Suffolk and Nassau/Queens) were set in suburban and urban areas, respectively, and had less frequent detections and lower pesticide concentrations than the PM network. Pesticide detections and concentration patterns (herbicide, insecticide, or fungicide) differed among the three networks revealing broad differences in land use. The predominance of fungicides metalaxyl, 1H-1,2,4-triazole (propiconazole/myclobutanil degradate), and 4-hydroxychlorothalonil (HCTL, chlorothalonil degradate) in samples from the PM network reflects their intensive use in agricultural settings. Total fungicide concentrations in the PM network ranged from <10 to >300,000 ng/L. The widespread detection of imidacloprid and triazine herbicides, simazine and atrazine, reveal a mixture of current and past use pesticides across the Long Island region. Low concentrations (<200 ng/L) of the triazines in the Suffolk and Nassau/Queens networks may reflect a change in land use and application. Acetanilide herbicides and aldicarb have been discontinued for 20 and 40 years, respectively, yet the concentrations of their degradates were among the highest observed in this study. Acetanilide (total concentrations up to 10,000 ng/L) and aldicarb degradates (up to 270 ng/L) are present in the PM network at much lower concentrations than previous Long Island studies and reflect changes in agricultural practices and pesticide management.

Impact of Unadorned Carbon Nitride on Photodegradation and Bioavailability of Multifungicides in the Environment

Unadorned carbon nitride was synthesized via different nitrogen-rich precursors by thermal polymerization and applied to multifungicides for simultaneous photodegradation in the present study. Urea-derived carbon nitride (UCN) was verified to be most efficient in fungicide removal. The influences of catalyst dosage and pH were studied during the photodegradation process. Hydroxyl radical (^•OH) and holes (h⁺) are the active species during photodegradation of each of the eight fungicides within an aqueous environment. The primary photodegradation products and pathways of all eight fungicides were systematically identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. In addition, the UCN catalyst was also applied to potted plants. The experimental results revealed that UCN could reduce fungicide residues in plants grown within a contaminated matrix. This study shows promising applications of the UCN catalyst in alleviating the hazards of pesticide residue.

An Overview of Strobilurin Fungicide Degradation:Current Status and Future Perspective

Strobilurin fungicides have been widely used in agricultural fields for decades. These pesticides are designed to manage fungal pathogens, although their broad-spectrum mode of action also produces non-target impacts. Therefore, the removal of strobilurins from ecosystems has received much attention. Different remediation technologies have been developed to eliminate pesticide residues from soil/water environments, such as photodecomposition, ozonation, adsorption, incineration, and biodegradation. Compared with conventional methods, bioremediation is considered a cost-effective and ecofriendly approach for the removal of pesticide residues. Several strobilurin-degrading microbes and microbial communities have been reported to effectively utilize pesticide residues as a carbon and nitrogen source. The degradation pathways of strobilurins and the fate of several metabolites have been reported. Further in-depth studies based on molecular biology and genetics are needed to elaborate their role in the evolution of novel catabolic pathways and the microbial degradation of strobilurins. The present review summarizes recent progress in strobilurin degradation and comprehensively discusses the potential of strobilurin-degrading microorganisms in the bioremediation of contaminated environments.

Degradation and metabolic profiling for benzene kresoxim-methyl using carbon-14 tracing

Benzene kresoxim-methyl (BKM) is an effective strobilurin fungicide for controlling fungal pathogens but limited information is available on its degradation and metabolism. This study explored the degradation and metabolic profiling for BKM in soils by carbon-14 tracing and HPLC-TOF-MS² analyzing. Results indicated that 88%-98% of ¹⁴C-BKM remained as parent or incomplete intermediates after 100 days. Three main radioactive metabolites (M1 to M3, ≥90%) and three subordinate radioactive metabolites (Ma to Mc, ≤2%) were observed, along with a non-radioactive metabolite M4. The main intermediates were further confirmed by self-synthesizing their authentic standards, and BKM was proposed to degrade via pathways including: 1) the oxidative cleavage of the acrylate double bond to give BKM-enol (M1); 2) the hydrolysis of the methyl ester to give BKM acid (M2); 3) the cleavage of M1 and M2 to yield Mc, which could be decarboxylated to give M3; and 4) the ether cleavage between aromatic rings to form M4. This study builds a solid metabolic profiling method for strobilurins and gives a deeper insight into the eventual fate of BKM by demonstrating its transformation pathways for the first time, which may also be beneficial for understanding the risks of other analogous strobilurins.