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Complexes with aromaticity in both the lowest singlet state (S0) and the lowest triplet state (T1) (denoted as adaptive aromaticity) are rare because according to Hückel's and Baird's rules, a species could be aromatic in either the S0 or T1 state in most cases. Thus, it is particularly challenging to design species with adaptive aromaticity. Previous reports on adaptive aromaticity were mainly focused on 16e metallapentalenes. Here, we demonstrate that 18e metallapentalenes could possess adaptive aromaticity supported by a set of aromaticity indices when the nitrido and imido ligands are introduced via density functional theory calculations. Further investigation suggests that the metal-carbon bond strength plays an important role in the S0 state aromaticity and the T1 state aromaticity could be attributed to spin electron localization. All these findings could be useful for the development of metallaaromatic chemistry.
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Tebuconazole is a widely used fungicide for various crops that targets sterol 14-α-demethylase (CYP51) in fungi. However, attention has shifted to aromatase (CYP19) due to limited research indicating its reproductive impact on aquatic organisms. Herein, zebrafish were exposed to 0.5 mg/L tebuconazole at different developmental stages. The proportion of males increased significantly after long-term exposure during the sex differentiation phase (0-60, 5-60, and 19-60 days postfertilization (dpf)). Testosterone levels increased and 17ß-estradiol and cyp19a1a expression levels decreased during the 5-60 dpf exposure, while the sex ratio was equally distributed on coexposure with 50 ng/L 17ß-estradiol. Chemically activated luciferase gene expression bioassays determined that the male-biased sex differentiation was not caused by tebuconazole directly binding to sex hormone receptors. Protein expression and phosphorylation levels were specifically altered in the vascular endothelial growth factor signaling pathway despite excluding the possibility of tebuconazole directly interacting with kinases. Aromatase was selected for potential target analysis. Molecular docking and aromatase activity assays demonstrated the interactions between tebuconazole and aromatase, highlighting that tebuconazole poses a threat to fish populations by inducing a gender imbalance.
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Diferenciación Sexual , Pez Cebra , Masculino , Animales , Diferenciación Sexual/genética , Aromatasa/genética , Aromatasa/metabolismo , Larva/metabolismo , Simulación del Acoplamiento Molecular , Factor A de Crecimiento Endotelial Vascular/metabolismo , Estradiol/metabolismoRESUMEN
The planting of transgenic rice has aroused ongoing controversy, due to the public anxiety surrounding the potential risk of transgenic rice to health and the environment. The soil microbial community plays an important environmental role in the plant-soil-microbe system; however, few studies have focused on the effect of transgenic rice on the soil rhizospheric microbiome. We labeled transgenic gene rice (TT51, transformed with Cry1Ab/1Ac gene), able to produce the Bt (Bacillus thuringiensis) toxin, its parental variety (Minghui 63), and a non-parental variety (9931) with 13CO2. The DNA of the associated soil rhizospheric microbes was extracted, subjected to density gradient centrifugation, followed by high-throughput sequencing of bacterial 16S rRNA gene. Unweighted unifrac analysis of the sequencing showed that transgenic rice did not significantly change the soil bacterial community structure compared with its parental variety. The order Opitutales, affiliated to phylum Verrucomicrobia and order Sphingobacteriales, was the main group of labeled bacteria in soil planted with the transgenic and parental varieties, while the orders Pedosphaerales, Chthoniobacteraceae, also affiliated to Verrucomicrobia, and the genus Geobacter, affiliated to class Deltaproteobacteria, dominated in the soil of the non-parental rice variety. The non-significant difference in soil bacterial community structure of labeled microbes between the transgenic and parental varieties, but the comparatively large difference with the non-parental variety, suggests a limited effect of planting transgenic Bt rice on the soil microbiome.
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Proteínas Bacterianas/metabolismo , Endotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Microbiota , Oryza/crecimiento & desarrollo , Plantas Modificadas Genéticamente/crecimiento & desarrollo , Rizosfera , Microbiología del Suelo , Toxinas de Bacillus thuringiensis , Dióxido de Carbono/metabolismo , Isótopos de Carbono/metabolismo , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Marcaje Isotópico , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
ZJ0712, a broad-spectrum fungicidal ingredient of strobilurin, exhibits a high protective and curative activity against plant pathogenic fungi. To support the study on its metabolism, residue, environmental behavior, and fate for safety evaluation, two versions of carbon-14 labeled ZJ0712, methyl (E)-2-(2-((2,5-dimethylphenoxy)methyl)phenyl)-3-methoxy[2-14 C]acrylate (2) and methyl (E)-2-(2-((2,5-dimethyl[phenyl-U-14 C6 ]phenoxy)methyl)phenyl)-3-methoxyacrylate (3), were synthesized from barium [14 C]carbonate in 6-step yield of 47% and from 2,5-dimethyl[phenyl-U-14 C6 ]phenol in the yield of 91%, respectively.
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Acrilatos/química , Radioisótopos de Carbono/química , Fungicidas Industriales/química , Fungicidas Industriales/síntesis química , Estrobilurinas/química , Estrobilurinas/síntesis química , Técnicas de Química Sintética , Marcaje IsotópicoRESUMEN
Benzene kresoxim-methyl (BKM) is a promising broad-spectrum strobilurin fungicide widely used to control fungal pathogens in crops. However, information on its environmental fate is limited. To broaden our understanding of this fungicide's kinetic fate in aerobic soils, we labeled BKM with C on its benzoate ring and used ultralow-level liquid scintillation counting coupled with high-performance liquid chromatography analysis. Results show that degradation, mineralization, and bound residue (BR) formation of BKM was controlled by soil type and microbial community composition. Degradation of BKM followed first-order dynamics, and the half-lives () were 51.7, 30.8, and 26.8 d for clay, loamy, and saline soils, respectively. After 100 d, about 0.13, 4.35, and 5.94% of the initial C-BKM was mineralized, and 14.43, 19.90, and 28.81% was formed as BRs in the clay, loamy, and saline soils, respectively. About 60 to 85% of the C-BKM residue in soil was extractable; of this fraction, 30 to 50% was composed of incomplete degradation intermediates. Up to 40% of extractable C-BKM in soil was readily available. Our results suggest that BKM and its incomplete intermediates had a relatively long persistence in soil, which may lead to exposure for nontarget organisms. Soil microbes may play a dominant role in controlling the fate of BKM in soil as sterilization sharply decreased its mineralization rate from 4.35 to 0.03%, increased from 30.8 to 85.6 d, and decreased the BR fraction from 19.90 to 3.25%.
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Fungicidas Industriales/química , Contaminantes del Suelo/química , Estrobilurinas/química , Benceno , SueloRESUMEN
Dufulin is a novel chiral plant antiviral agent. In this study, we investigated the uptake, translocation and accumulation of 14C-dufulin stereoisomers in different tissues of garlic via leaf introduction and root uptake. The behavior of dufulin enantiomers in plants is not stereoselective, and dufulin is more likely to be absorbed by leaves than by roots. The metabolites of 14C-dufulin with high specific activity in garlic were qualitatively and quantitatively analyzed by HPLC-QTOF-MS, and the metabolic pathway involved was elucidated. In the leaf and bulb, dufulin underwent phase I and phase II metabolism and produced four metabolites. The ratios and concentrations of these four metabolites in the bulb, but not in the leaf, met the residue criterion. Overall, our results provide relatively accurate predictions for the risk assessment of dufulin, which will help guide its rational use and ensure its ecological safety and human health.
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The accumulation of atrazine in soils can create environmental challenges, potentially posing risks to human health. Superabsorbent hydrogel (SH)-based formulations offer an eco-friendly approach to accelerate herbicide degradation. However, the impact of SHs on soil microbial community structure, and thus on the fate of atrazine, remains uncertain. In this study, a radioactive tracer was employed to investigate the influence of SHs on microbial communities and atrazine transformation in soils. The results revealed that the mineralization of atrazine in active soils was considerably greater than that in sterilized soils. Atrazine degradation proceeded rapidly under SH treatment, indicating the potential of SH to accelerate atrazine degradation. Furthermore, SH addition did not alter the atrazine degradation pathway in soils, which included dealkylation, dechlorination and hydroxylation. The relative abundance of dominant microbial population was influenced by the presence of SHs in the soil. Additionally, SH application led to an increased relative abundance of Lysobacter, suggesting its potential involvement in atrazine degradation. These findings reveal the significance of soil microorganisms and SH in atrazine degradation, offering crucial insights for the development of effective strategies for atrazine remediation and environmental sustainability.
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Atrazine exhibits adverse effects on diverse organisms in both terrestrial and aquatic environments, even though it effectively targets specific organisms. This study employed superabsorbent hydrogels to coat 14C-atrazine coupled with a four-compartment model to determine the fate of this herbicide in three oxic soils over a 100-day incubation period. Mineralization of atrazine was limited in all soils, with rates remaining below 3.5 %. The encapsulation treatment reduced mineralization of atrazine in soil A and soil B. Bound residues ranged from 26.1 to 43.6 % at 100 d. The encapsulation treatment enhanced the degradation of atrazine and reduced the content of deethylatrazine in soil A, but significantly increased the content of deisopropylatrazine in soil A and hydroxyatrazine in soil C. Using the obtained data, we also constructed a four-compartment model to clarify the relationships among the parent compound, degradation products, bound residues, and mineralization. This model accurately fits the fate of atrazine in the present work. Additionally, the correlation study suggested that both soil parameters and superabsorbent hydrogels played significant roles in influencing atrazine transformation. These findings serve as a reference for evaluating the environmental impact of superabsorbent hydrogels in atrazine pollution reduction and offer a foundational model approach for a comprehensive understanding of organic pollutants.
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Microplastics (MPs) and pesticides commonly exist in the environment, yet the interactions between them and their subsequent impacts on plants remain poorly understood. Thus, this study aimed to investigate the impacts of differently charged polystyrene (PS) MPs, including PS-COO-, PS and PS-NH3+ MPs, on the fate of 14C-labelled new antiviral pesticide Dufulin (DFL) in a hydroponic tomato system. The results showed that MPs greatly reduced the growth of tomato plants, with suppression of 18.4-30.2%. Compared to the control group, PS-COO-, PS and PS-NH3+ MPs also reduced the bioaccumulation of DFL in whole tomato plants by 40.3%, 34.5%, and 26.1%, respectively. Furthermore, MPs influenced the translocation of DFL in plant tissues, and the values decreased at the rates of 38.7%, 26.5% and 15.7% for PS-COO-, PS and PS-NH3+, respectively. Interestingly, compared to the control group, PS-COO- exhibited a profound inhibitory effect on DFL concentrations in tomatoes, potentially resulting in a lower dietary risk in the hydroponic tomato system. This may be due to the strong adsorption between PS-COO- and DFL, and PS-COO- may also inhibit the growth of tomato plants. Overall, our study could provide valuable insights into the risk assessment of DFL in the presence of MPs in plant systems.
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Benzotiazoles , Plaguicidas , Solanum lycopersicum , Disponibilidad Biológica , Microplásticos/toxicidad , Plásticos , PoliestirenosRESUMEN
INTRODUCTION: Since the outbreak of COVID-19, microplastics (MPs) and triclosan in pharmaceuticals and personal care products (PPCPs) are markedly rising. MPs and triclosan are co-present in the environment, but their interactions and subsequent implications on the fate of triclosan in plants are not well understood. OBJECTIVE: This study aimed to investigate effects of charged polystyrene microplastics (PS-MPs) on the fate of triclosan in cabbage plants under a hydroponic system. METHODS: 14C-labeling method and liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (LC-QTOF-MS) analysis were applied to clarify the bioaccumulation, distribution, and metabolism of triclosan in hydroponics-cabbage system. The distribution of differentially charged PS-MPs in cabbage was investigated by confocal laser scanning microscopy and scanning electron microscopy. RESULTS: The results showed that MPs had a significant impact on bioaccumulation and metabolism of triclosan in hydroponics-cabbage system. PS-COO-, PS, and PS-NH3+ MPs decreased the bioaccumulation of triclosan in cabbage by 69.1 %, 81.5 %, and 87.7 %, respectively, in comparison with the non-MP treatment (control). PS-MPs also reduced the translocation of triclosan from the roots to the shoots in cabbage, with a reduction rate of 15.6 %, 28.3 %, and 65.8 % for PS-COO-, PS, and PS-NH3+, respectively. In addition, PS-NH3+ profoundly inhibited the triclosan metabolism pathways such as sulfonation, nitration, and nitrosation in the hydroponics-cabbage system. The above findings might be linked to strong adsorption between PS-NH3+ and triclosan, and PS-NH3+ may also potentially inhibit the growth of cabbage. Specially, the amount of triclosan adsorbed on PS-NH3+ was significantly greater than that on PS and PS-COO-. The cabbage biomass was reduced by 76.9 % in PS-NH3+ groups, in comparison with the control. CONCLUSION: The uptake and transformation of triclosan in hydroponics-cabbage system were significantly inhibited by charged PS-MPs, especially PS-NH3+. This provides new insights into the fate of triclosan and other PPCPs coexisted with microplastics for potential risk assessments.
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Increasing use and release of graphene nanomaterials and pharmaceutical and personal care products (PPCPs) in soil environment have polluted the environment and posed high ecological risks. However, little is understood about the interactive effects and mechanism of graphene on the behaviors of PPCPs in soil. In the present study, the effects of reduced graphene oxide nanomaterials (RGO) on the fate of triclosan in two typical soils (S1: silty loam; S2: silty clay loam) were investigated with 14C-triclosan, high-resolution mass spectrometry, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations, and microbial community structure analysis. The results showed that RGO prolonged the half-life of triclosan by 23.6-51.3 %, but delayed the formation of transformed products such as methyl triclosan and dechlorinated dimer of triclosan in the two typical soils. Mineralization of triclosan to 14CO2 was inhibited by 48.2-79.3 % in 500 mg kg-1 RGO in comparison with that in the control, whereas the bound residue was 54.2-56.4 % greater than the control. RGO also reduced the relative abundances of triclosan-degrading bacteria (Pseudomonas and Sphingomonas) in soils. Compared to silty loam, RGO more effectively inhibited triclosan degradation in silty clay loam. Furthermore, the DFT calculations suggested a strong association of the adsorption of triclosan on RGO with the van der Waals forces and π-π interactions. These results revealed that RGO inhibited the transformation of 14C-triclosan in soil through strong adsorption and triclosan-degrading bacteria inhibition in soils. Therefore, the presence of RGO may potentially enhance persistence of triclosan in soil. Overall, our study provides valuable insights into the risk assessment of triclosan in the presence of GNs in soil environment.
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Grafito , Nanoestructuras , Contaminantes del Suelo , Suelo , Triclosán , Grafito/química , Suelo/química , Microbiología del Suelo , Radioisótopos de CarbonoRESUMEN
The antiepileptic drug carbamazepine (CBZ) is one of the most frequently detected human pharmaceuticals in wastewater effluents and biosolids. Soil is a primary environmental compartment receiving CBZ through wastewater irrigation and biosolid application. In this study, we explored the transformation of CBZ to biologically active intermediates in soil. Both (14)C labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to track transformation kinetics and identify major degradation intermediates. Through 120 days of incubation under aerobic conditions, mineralization of CBZ did not exceed 2% of the spiked rate in different soils. Amendment of biosolids further suppressed mineralization. The fraction of non-extractable (i.e., bound) residue also remained negligible (<5%). On the other hand, CBZ was transformed to a range of degradation intermediates, including 10,11-dihydro-10-hydroxycarbamazepine, carbamazepine-10,11-epoxide, acridone-N-carbaldehyde, 4-aldehyde-9-acridone, and acridine, of which acridone-N-carbaldehyde was formed in a large fraction and appeared to be recalcitrant to further degradation. Electrocyclization, ring cleavage, hydrogen shift, carbonylation, and decarbonylation contributed to CBZ transformative reactions in soil, producing biologically active products. The persistence of the parent compound and formation of incomplete intermediates suggest that CBZ has a high risk for off-site transport from soil, such as accumulation into plants and contamination of groundwater.
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Carbamazepina/química , Carbamazepina/metabolismo , Contaminantes del Suelo/química , Contaminantes del Suelo/metabolismo , Suelo/química , Aerobiosis , Agricultura , Dióxido de Carbono/análisis , Isótopos de Carbono , Fenómenos Químicos , Semivida , Humanos , Cinética , Espectrometría de Masas , Minerales/químicaRESUMEN
Many pesticides are chiral but used as racemic mixtures, even though their stereoisomers are often degraded stereoselectively in soils. Evaluation of degradation of chiral compounds is mostly focused on the enantioselectivity rather than diastereoselectivity/epimer preferences. In this study, we explored the diastereoselective transformation of paichongding (IPP), a novel chiral neonicotinoid with broad-spectrum insecticidal activity, to several degradation intermediates in different soils. (14)C-Labeling coupled with LC-MS/MS and high resolution MS were used to track residues of IPP and identify major transformation metabolites. The stereoisomers of IPP known as 5R, 7R-IPP (RR-IPP), 5S, 7S-IPP (SS-IPP), 5S, 7R-IPP (SR-IPP), and 5R, 7S-IPP (RS-IPP) showed diastereoselective/epimer-selective persistence in all soils except an acidic clay soil. Moreover, IPP was transformed to a range of degradation intermediates (M1-M6), which also showed significant diastereoselective and soil preferential formation. Depropylation, nitrosylation, denitration, demethylation, dehydroxylation, and ketonization contributed to IPP transformation. The diastereoselective degradation of the parent compound and formation of incomplete intermediates implies that diastereomers/epimers should be regarded as different chemicals. The approach of coupling (14)C and MS may be used as an effective tool to understand the environmental processes and risks of other man-made chiral compounds.
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Compuestos de Azabiciclo/metabolismo , Insecticidas/metabolismo , Piridinas/metabolismo , Contaminantes del Suelo/metabolismo , Aerobiosis , Compuestos de Azabiciclo/química , Biodegradación Ambiental , Insecticidas/química , Piridinas/química , Microbiología del Suelo , Contaminantes del Suelo/química , EstereoisomerismoRESUMEN
Chiral insecticide paichongding (IPP) is one of the prospective substitutes for imidacloprid used in China due to its higher activity against imidacloprid-resistant insects. However, little is known about the fate of IPP in soils, including especially the different behaviors among its stereoisomers. In this study, four stereoisomers of IPP were separated and applied in flooded soils. Kinetics of mineralization, extractable residues, and bound residues showed diastereoselectivity in IPP degradation, with enantiomers (5S,7R)-IPP (IPP-SR) and (5R,7S)-IPP (IPP-RS) being more readily mineralized and preferentially bound to soils than enantiomers (5R,7R)-IPP (IPP-RR) and (5S,7S)-IPP (IPP-SS). The overall mineralization was rather limited and did not exceed 4% of the spiked rate. Concurrent to the decreases of extractable residues, the fraction of bound residues increased with time and reached about 34% of the applied radioactivity for (14)C-IPP-SR and (14)C-IPP-RS as compared to about 23% for (14)C-IPP-RR or (14)C-IPP-SS. Soil properties such as organic matter content and pH likely contributed to the variability. Relatively rapid formation of bound residue suggests that IPP may be quickly detoxified in flooded paddy soil, decreasing the potential for off-site transport such as leaching or runoff, especially for enantiomers IPP-SR and IPP-RS.
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Compuestos de Azabiciclo/química , Compuestos de Azabiciclo/aislamiento & purificación , Inundaciones , Insecticidas/aislamiento & purificación , Oryza/crecimiento & desarrollo , Piridinas/química , Piridinas/aislamiento & purificación , Contaminantes del Suelo/aislamiento & purificación , Suelo/química , Dióxido de Carbono/química , Radioisótopos de Carbono/análisis , Fraccionamiento Químico , Cromatografía Líquida de Alta Presión , Insecticidas/química , Minerales/química , Contaminantes del Suelo/química , EstereoisomerismoRESUMEN
For a novel potential commercial chiral pesticide, an independent study on the fate characteristics and residues of each stereoisomer is essential if the application rates for the pesticide and human exposure are to be reduced. The absorption and translocation behavior of a chiral insecticide, cycloxaprid, in plants treated by root immersion and blade smearing was studied using (14)C-labeling tracer techniques. With the root treatment, total absorption of (1R;8S)-cycloxaprid (RS) (12.39%) was much greater than that of (1S;8R)-cycloxaprid (SR) (3.31%) at 192 h after treatment (HAT). The mass concentrations (RS/SR) of cycloxaprid in the roots, cotyledons, leaf 1, leaf 2, and leaf 3 were 37.0/16.8, 8.3/2.8, 11.7/6.5, 5.1/4.8, and 8.0/4.7 mg kg(-1) (fresh weight), respectively, at 192 HAT at an initial concentration 1.6 mg kg(-1). With the foliar application treatment, no significant difference was observed between the total absorption of RS (3.11%) and SR (4.03%) at the end of the treatment. Both acropetal and basipetal transport of absorbed (14)C occurred and more than 71.83% of absorbed RS and 82.42% of SR remained in the treated leaf. Stereoselective absorption was observed during root uptake but not during foliar absorption.
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Brassica/metabolismo , Compuestos Heterocíclicos con 3 Anillos/química , Compuestos Heterocíclicos con 3 Anillos/metabolismo , Insecticidas/química , Insecticidas/metabolismo , Piridinas/química , Piridinas/metabolismo , Absorción , Transporte Biológico , Raíces de Plantas/metabolismo , EstereoisomerismoRESUMEN
Pesticide use can result in plant residues, which can be ingested by livestock consuming plant-derived feed and appear in manure. When this manure is applied as a fertilizer, pesticides can contaminate plant-soil systems. Few studies have focused on pesticide infiltration from applying pesticide-contaminated manure to land. In this study, the fate of pesticide vanisulfane from chicken manure was studied in radish-soil and cabbage-soil systems assisted by carbon-14 labeling. Vanisulfane and its metabolites mostly appeared as bound residues (BRs) after introduction, and BR release was found at 35 d. Notably, manure contaminated with vanisulfane and its metabolites exhibited higher plant accumulation and phytotoxicity than manure contaminated with only the parent. Four metabolites were identified, and germination toxicity assays illustrated that a metabolite with an aldehyde structure induced phytotoxicity. This study provides valuable information on pesticide contamination from manure and emphasizes the importance of considering pesticide metabolites when assessing environmental risks.
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Plaguicidas , Contaminantes del Suelo , Animales , Suelo/química , Estiércol/análisis , Radioisótopos de Carbono , Contaminantes del Suelo/análisisRESUMEN
Dufulin (DFL), a plant antiviral agent synthesized in China, has been widely used to control viral diseases in rice, tobacco, tomato, and other crops. However, its fate in flooded anaerobic soils, which is essential for environmental risk assessment, remains unknown. Using the 14C tracer technique, the fate of 14C-labeled DFL isomers in flooded anaerobic soils was systematically investigated in this study. Over the 100-day incubation, a small part of 14C-DFL enantiomer was mineralized to 14CO2 (< 10.44 %) or entered the surface water phase (< 6.69 %), with most of the 14C (> 80.40 %) remaining in the subsoil. The residues in all tested soils were gradually converted from extractable residues (ERs) to nonextractable residues (NERs). At the end of incubation, the fraction of 14C-NERs reached 5.38-23.77 %. The half-life (t1/2) of the DFL parent in soil is relatively long under submerged anaerobic conditions, especially in Fluvo-aquic soil, up to 277.26-315.07 days, which exceeds the risk threshold recommended by the Stockholm Convention (< 180 days). Soil type and microbial activity influenced the fate of DFL in flooded soils and microbial analysis showed that 2.0 mg kg-1 DFL had no obvious impact on soil bacterial richness and function. Pseudomonas spp. was estimated to be a potentially efficient degrading genus for DFL. No enantioselective behaviors were detected in this study. This research provides a theoretical basis for evaluating the environmental impact and ecological safety of DFL application.
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Plaguicidas , Contaminantes del Suelo , Plaguicidas/química , Suelo/química , Anaerobiosis , Contaminantes del Suelo/análisisRESUMEN
As a best-selling triazolinthione fungicide, prothioconazole (PTZ) has been widely used worldwide and has aroused concern about its environmental effect. This study used phenyl-UL-14C-labeled PTZ and an improved fate model to investigate the fate and metabolism of this fungicide in aerobic soil. During 120 d of incubation, PTZ rapidly transformed into metabolites and bound residues, with a half-life (DT50) of less than 1 d. After 120 d, approximately 45-55% of PTZ formed bound residues, and the extractable metabolite residues were gradually degraded over time. Approximately 19%, 44% and 27% of phenyl-UL-14C-PTZ was mineralized in red soil, fluvo-aquic soil and cinnamon soil, respectively, but only approximately 3% was mineralized in black soil. Five metabolites were identified and confirmed, and a possible metabolic pathway for phenyl-UL-14C-PTZ in soil was proposed. Based on the correlation analysis between soil properties and model rate constants, soil properties exerted important effects on PTZ transformation. These results will provide basic data for environmental risk assessments and removal of the PTZ pollutant and suggest that the soil type should be considered in the selection and application of pesticides.
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Fungicidas Industriales , Plaguicidas , Contaminantes del Suelo , Fungicidas Industriales/química , Suelo/química , Contaminantes del Suelo/análisisRESUMEN
Dufulin is a promising chiral antiviral agent, but little is known about its fate in soils. In this study, the fate of dufulin enantiomers in aerobic soils was investigated using radioisotope tracing techniques. The result of the four-compartment model showed no significant differences in dissipation, generation of bound residues (BR) and mineralization between S-dufulin and R-dufulin during incubation. Dufulin dissipated most quickly in cinnamon soils, followed by fluvo-aquic and black soils and the half-lives of dufulin in these soils obtained by the modified model were 4.92-5.23, 32.39-33.32 and 60.80-61.34 d, respectively. After 120 d incubation, the percentage of radioactivity of BR increased to 18.2-38.4 % in the three soils. Dufulin formed most bound residues in the black soil, least in the cinnamon soil, and BRs rapidly formed in the cinnamon soil during the early culture period. In these three soils, the cumulative mineralization of 14CO2 ranged from 25.0 to 26.7 %, 42.1 to 43.4 % and 33.8 to 34.4 %, respectively, which indicated that the environmental fate of dufulin was primarily influenced by soil characteristics. The study of microbial community structure revealed that the phyla Ascomycota, Proteobacteria and genus Mortierella might be related to the degradation of dufulin. These findings provide a reference for assessing the environmental impact and ecological safety of dufulin application.
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Plaguicidas , Contaminantes del Suelo , Plaguicidas/química , Suelo/química , Contaminantes del Suelo/análisis , Benzotiazoles/análisisRESUMEN
Due to their ubiquity and potential risks, microplastics (MPs) and nanoplastics (NPs) are concerning environmental issues. Yet there are still significant knowledge gaps in understanding the tissue-specific accumulation and dynamic change of MPs and NPs in the aquatic organism and how these micro/nano-scale emerging contaminants interact with other environmental pollutants such as persistent organic pollutants (POPs). Here, in vivo imaging systems (IVIS), radioisotope tracing, and histological staining were innovatively used to reveal the fate and toxicity of fluorescently-labeled MPs/NPs and 14C-labeled 2,4,4'-trichlorobiphenyl (PCB28) in edible jellyfish Rhopilema esculentum. These contaminants' ingestion, biological effects, and interactions were visualized at cellular, tissue, and whole-body multidimensional levels. Both MPs and NPs were shown to be preferentially accumulated in the mouthlets of oral arms, and most ingested MPs/NPs were present in the extracellular environment instead of being internalized into the mesoglea. Moreover, the presence of MPs or NPs in the seawater significantly inhibited the bioaccumulation of PCB28 in the jellyfish tissue, thus alleviating physiological alteration, gastric damage, and apoptosis caused by PCB28. This study provides a multi-dimensional visualization strategy to display the distribution and biological effects of typical pollutants in marine organisms and offers new insights for understanding the impacts of MPs/NPs and POPs on marine ecosystems.