Accumulation, translocation, metabolism and subcellular distribution of mandipropamid in cherry radish: A comparative study under hydroponic and soil-cultivated conditions

The accumulation and transportation of pesticides in plants can provide valuable insights to assess potential risks and ensure food safety. The uptake and downward translocation of mandipropamid were examined in hydroponic and soil-cultivated cherry radishes. The uptake of mandipropamid in cherry radish was rapid (bioconcentration factors of 1.1-10.7), whereas the downward translocation was limited (translocation factors of 0.1-0.9). The subcellular distribution results indicated a predominant accumulation in solid fractions of cherry radish (proportions of 52.9-98.7%), potentially because of the hydrophobicity (log Kow of 3.2) of mandipropamid. Owing to the decrease in half-life (>10%), the cultivation of cherry radish enhanced the dissipation of mandipropamid in both nutrient solutions (without stereoselectivity) and soils (with stereoselectivity). In addition, eleven metabolites and three pathways are proposed. This study provides valuable insights for the varying extent of translocation and proper utilization and safety evaluation of mandipropamid in crops.

Evaluation of Iron Chlorin e6 disappearance and hydrolysis in soil and garlic using salting-out assisted liquid-liquid extraction coupled with high-performance liquid chromatography and ultraviolet-visible detection

Iron Chlorin e6 (ICE6), a star plant growth regulator (PGR) with independent intellectual property rights in China, has demonstrated its efficacy through numerous field experiments. We innovatively employed salting-out assisted liquid-liquid extraction (SALLE) with HPLC-UV/Vis to detect ICE6 residues in water, soil, garlic seeds, and sprouts. Using methanol and a C18 column with acetonitrile: 0.1% phosphoric acid mobile phase (55:45, v:v), we achieved a low LOQ of 0.43 to 0.77 μg kg-1. Calibration curves showed strong linearity (R2 > 0.992) within 0.01 to 5.00 mg kg-1. Inter-day and intra-day recoveries (0.05 to 0.50 mg kg-1) demonstrated high sensitivity and accuracy (recoveries: 75.36% to 107.86%; RSD: 1.03% to 8.78%). Additionally, density functional theory (DFT) analysis aligned UV/Vis spectra and indicated ICE6's first-order degradation (2.03 to 4.94 days) under various environmental conditions, mainly driven by abiotic degradation. This study enhances understanding of ICE6's environmental behavior, aids in risk assessment, and guides responsible use in agroecosystems.

Potential effects of individual and combined exposure to tetraconazole and cadmium on zebrafish from the perspective of enantioselectivity and intestinal microbiota

As the wide use of pesticides, they could form combined pollution with heavy metals, which would affect their environmental behaviors and toxic effects. Particularly, the effects would be more intricate for chiral pesticides. In this study, the accumulation and dissipation trends of tetraconazole enantiomers in zebrafish were investigated by individual and combined exposure of cadmium (Cd) and tetraconazole (including racemate and enantiomers) after confirming the absolute configuration of tetraconazole enantiomer. For the enantiomer treatments, Cd enhanced the accumulation of S-(+)-tetraconazole, but declined the concentrations of R-(-)-tetraconazole in zebrafish. The dissipation half-lives of tetraconazole enantiomers were extended by 1.65-1.44 times after the combined exposure of Cd and enantiomers. The community richness and diversity of intestinal microbiota were reduced in all treatments, and there were significant differences in R + Cd treatment. There was synergistic effect between Cd and S-(+)-tetraconazole for the effects on the relative abundances of Fusobacteria, Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes. For R-(-)-tetraconazole, Cd mainly exhibited antagonistic effects. In the combined exposure of Cd and S-(+)-tetraconazole, the relative abundance changes of Cetobacterium (Fusobacteria, increase) and Edwardsiella (Proteobacteria, decrease) might affect the carbohydrate metabolism and energy metabolism, and led to the increase of S-(+)-tetraconazole bioaccumulation concentration. In the combined exposure of Cd and R-(-)-tetraconazole, Cd could increase the relative abundance of Edwardsiella (Proteobacteria), and affect the amino acid metabolism, which might reduce the bioaccumulation concentration of R-(-)-tetraconazole. This study reported for the first time that the abundance of intestinal microbiota in zebrafish might affect the bioaccumulation and dissipation of tetraconazole enantiomers, and would provide new insight for the study of combined pollutions.

Residual estimation of spirotetramat and its metabolites in chilli and soil by LC-MS/MS

Two applications of spirotetramat were done to study the dissipation and persistence of spirotetramat and its four different metabolites in chilli and soil at 10 days interval. Total spirotetramat residues were estimated by LC-MS/MS instrument. The mean initial deposits of total spirotetramat after application of spirotetramat 15.31 OD @ 60 (X dose), 75 (1.25 × dose) and 120 (2 × dose) g a.i. ha-1 on green chilli were found to vary from 0.38 to 0.83 mg kg-1 during the initial year. Spirotetramat and its metabolite residues in green chilli were found to be below limit of quantification (0.01 mg kg-1) after 15 days of application. The spirotetramat cis enol (the major metabolite) was formed in both the soil and the plant. The residues of spirotetramat-monohydroxy were below LOQ irrespective of any substrate during the estimation. In soil, the total initial spirotetramat deposits for the 1st year were found 0.09 for X dose, 0.12 for 1.25 × dose and 0.20 mg kg-1 for 2 × dose. After 3 days for both X and 1.25 × doses and 5 days for 2 × dose, the total spirotetramat residues were below LOQ. The spirotetramat's half-life values have been determined to be between 3.19 and 3.93 days and 1.00 and 1.59 days, respectively, in soil and green chilli fruits. One day waiting period is proposed for the safe consumption of green chilli when the spirotetramat was applied irrespective of the dose.

Investigation of dissipation kinetics and half-lives of fipronil and thiamethoxam in soil under various conditions using experimental modeling design by Minitab software

To determine the extent of pesticide buildup and their environmental contamination, the environmental half-lives of pesticides are examined. The influence of the factors affecting the half-lives of fipronil and thiamethoxam including soil type, sterilization, temperature, and time and their interactions was studied using experimental modeling design by Minitab software. Based on the dissipation kinetics data, fipronil concentrations reduced gradually over 60 days while thiamethoxam concentrations decreased strongly. Also, fipronil and thiamethoxam dissipated more rapidly in calcareous soil than in alluvial soil. Thiamethoxam, however, disappeared more rapidly than fipronil in all treatments. Incubation at 50 °C leads to rapid the pesticide degradation. For prediction of the dissipation rate, model 5 was found to be the best fit, Residue of insecticide (%) = 15.466 - 11.793 Pesticide - 1.579 Soil type + 0.566 Sterilization - 3.120 Temperature, R2 = 0.94 and s = 3.80. Also, the predicted DT50 values were calculated by a model, DT50 (day) = 20.20 - 0.30 Pesticide - 7.97 Soil Type + 0.07 Sterilization - 2.04 Temperature. The shortest experimental and predicted DT50 values were obtained from treatment of thiamethoxam at 50 °C in calcareous soil either sterilized (7.36 and 9.96 days) or non-sterilized (5.92 and 9.82 days), respectively. The experimental DT50 values of fipronil and thiamethoxam ranged from 5.92 to 59.95 days while, the modeled values ranged from 9.82 to 30.58 days. According to the contour plot and response surface plot, temperature and sterilization were the main factors affecting the half-lives of fipronil and thiamethoxam. The DT50 values of fipronil and thiamethoxam increased in alluvial soil and soil with low temperature. In general, there is a high agreement between the experimental results and the modeled results.

Synergistic mechanism and environmental behavior of tank-mix adjuvants to topramezone and atrazine

An effective way to reduce herbicide quantity is to use adjuvants in order to optimize the amount of herbicide and improve its control efficiency. In order to screen for efficient herbicide tank-mix adjuvants, improve the control of weeds in maize fields, reduce the amount of effective ingredients, and improve the adsorption and digestion behavior of herbicides in soil, this study evaluated the synergistic effects and soil behavior of four types of tank-mix adjuvants combined with herbicides. Different types of adjuvants can enhance herbicide production. Surface tension was significantly reduced by 13% after the pesticide solution was applied with AgroSpred™ Prime. The contact angle with the foliar surface was significantly reduced and solution wettability improved using Atp Lus 245-LQ-(TH). The permeability of topramezone and atrazine in leaves of Amaranthus retroflexus L. and Digitaria sanguinalis (L.) Scop. was increased by 22-96% after adding either tank-mix adjuvant. The solution drying time and maximum retention on leaves were not affected by the tank-mix adjuvants. Ethyl and methylated vegetable oils can reduce the adsorption of topramezone in the soil, thus reducing its half-life in soil. The tank-mix adjuvants had no significant effect on soil dissipation or adsorption of atrazine. AgroSpred™ Prime and Atp Lus 245-LQ-(TH) have the best synergistic effect on topramezone and atrazine in the control of A. retroflexus L. and D. sanguinalis (L.) Scop. in maize fields.

Characteristics of bacterial community and extracellular enzymes in response to atrazine application in black soil

The ecological functioning of black soil largely depends on the activities of various groups of microorganisms. However, little is known about how atrazine, a widely used herbicide with known harmful effects on the environment, influences the microbial ecology of black soil, and the extracellular enzymes related to the carbon, nitrogen and phosphorus cycles. Here, we evaluated the change in extracellular enzymes and bacterial community characteristics in black soil after exposure to various concentrations of atrazine. Low concentrations of applied atrazine (10 - 20 mg kg-1) were almost completely degraded after 120 days. At high concentrations (80 - 100 mg kg-1), about 95% of the applied atrazine was degraded over the same period. Additionally, linear fitting of data indicated that the total enzymatic activity index (TEI) and bacterial α-diversity index were negatively correlated with atrazine applied concentration. The atrazine had a greater effect on bacterial beta diversity after 120 days, which differentiated species clusters treated with low and high atrazine concentrations. Soil bacterial community structure and function were affected by atrazine, especially at high atrazine concentrations (80 - 100 mg kg-1). Key microorganisms such as Sphingomonas and Nocardioides were identified as biomarkers for atrazine dissipation. Functional prediction indicated that most metabolic pathways might be involved in atrazine dissipation. Overall, the findings enhance our understanding of the factors driving atrazine degradation in black soil and supports the use of biomarkers as indicators of atrazine dissipation.

Spatiotemporal dynamics and modeling of thiacloprid in paddy multimedia systems with the effect of wetting-drying cycles

The widespread presence of thiacloprid (THI), a neonicotinoid, raises concerns for human health and the aquatic environment due to its persistence, toxicity, and bioaccumulation. The fate of THI in paddy multimedia systems is mainly governed by irrigation practices, but the potential impacts remain poorly documented. This study investigated the effects of water management practices on THI spatiotemporal dynamics in paddy multimedia systems by combining soil column experiments and a non-steady-state multimedia model. The results indicated the wetting-drying cycle (WDC) irrigation reduced THI occurrences in environmental phases (i.e., soil, interstitial water, and overlying water) and accelerated the THI loss through the THI aerobic degradation process. THI occurrences in the soil and water phases decreased from 18.8% for conventional flooding (CF) treatment to 9.2% for severe wetting-drying cycle (SW) treatment after 29 days, while the half-lives shortened from 11.1 days to 7.3 days, respectively. Meanwhile, the WDC decreased THI outflow from leakage water, which reduced the THI risk of leaching. There was no significant difference in THI plant uptake and volatilization between CF and WDC treatments. The mean proportions of THI fate in paddy multimedia systems followed the order: THI degradation (57.7%), outflow from leakage water (25.5%), occurrence in soil (12.4%), plant uptake (3.4%), occurrence in interstitial water (0.7%), occurrence in overlying water (0.3%), volatilization (<0.1%) after 29 days. The sensitivity analysis identified the soil organic carbon partition coefficient (KOC) as the most sensitive parameter affecting THI's fate. In addition, the topsoil layers of 0-4 cm were the main sink of THI, holding 67% of THI occurrence in the soil phase. The THI occurrence in interstitial water was distributed evenly throughout the soil profile. These findings made beneficial theoretical supplements and provided valuable empirical evidence for water management practices to reduce the THI ecological risk.

Analysis, residue behaviour and risk assessment of combination product of iprovalicarb + copper oxychloride in representative fruiting vegetables, cucurbit and in soil using LC-MS/MS and ICP-MS

Combination product of two herbicides, i.e. iprovalicarb and copper oxychloride, is a new formulation. There is paucity of data on the dissipation pattern and risk assessment of this combination product in crops. To understand the dissipation behaviour/kinetics of this product, a supervised field trial was undertaken on cucumber and tomato. Method validation for a QuEChERS-based method for analysis of these pesticides from cucumber and tomato matrices reveals that all the parameters were within the acceptance range in accordance with SANTE. The limit of quantitation (LOQ) for iprovalicarb in cucumber and tomato fruits, and in soil matrices when analysed on LC-MS/MS was established at 0.01 mg kg-1. Similarly, the LOQ for copper oxychloride (as copper) on ICP-MS was established at 0.5 mg kg-1 in cucumber and tomato fruits and 5.0 mg kg-1 in soil. Dissipation of iprovalicarb was slower in tomato fruits as compared to cucumber fruits. The initial accumulation of the residues of iprovalicarb was 0.073 and 0.243 mg kg-1 in cucumber and 0.214 and 0.432 mg kg-1 in tomato fruits at standard and double dose, respectively. Similarly, copper oxychloride residues were 3.51 and 6.45 mg kg-1 in cucumber and 1.26 and 2.56 mg kg-1 in tomato fruits at standard and double dose, respectively. The residues were below LOQ in cucumber fruits, tomato fruits and soil at the time of harvest. The residues of copper oxychloride persisted till harvest time in cucumber fruits and in soil. A preharvest interval (PHI) of 3 day is recommended on safer side for the combination product of iprovalicarb + copper oxychloride. Theoretical maximum daily intake (TMDI) is less than maximum permissible intake (MPI) for iprovalicarb and copper oxychloride at both the doses from 0 day and onward. The results from the present study can be of immense importance for establishing label claims, maximum residue limits (MRLs) and risk assessment by national and international regulatory agencies.

Thiamethoxam dynamics in pepper plants: Deciphering deposition and dissipation pattern across diverse planting modes and regions

To reduce the application dosage of thiamethoxam (TMX), we investigated the deposition and dissipation patterns in a pepper-planted ecosystem under different planting modes across four regions in China, namely Hainan (HN), Zhejiang (ZJ), Anhui (AH) and Hebei (HB). This study focused on the deposition and dissipation of TMX at concentrations of 63.00, 47.25, 31.50, 23.63 and 15.75 g a.i.hm-2. As the application dose increased, the deposition amount of TMX initially increased in the plants and cultivated soil, showing obvious geographic differences in four cultivation areas. Surprisingly, the initial amount of TMX deposited the pepper-cultivated greenhouse of ZJ and AH was 1.1-2.1-fold and 1.0-3.6-fold higher than that in the open field system at the same application dose, respectively. In pepper leaves, stems, fruits and soil, the dissipation exhibited rapid growth and then slowed. However, the residual concentration showed an increasing trend, followed by a subsequent decrease in the pepper roots. In different planting regions, the dissipation rate of TMX followed the order HN > ZJ > AH > HB in pepper plants and cultivated soil. In comparison to the open field, the total TMX retention rate in greenhouse was higher, indicating overall greater persistence in the greenhouse conditions. These findings reveal the deposition and dissipation characteristics of TMX within the pepper-field ecosystem, offering a significant contribution to the risk assessment of pesticides.

Fate and toxicity of 2,4-D and fipronil in mesocosm systems

2,4-D and fipronil are among Brazil's most used pesticides. The presence of these substances in surface waters is a concern for the aquatic ecosystem health. Thus, understanding the behavior of these substances under environmentally relevant conditions is essential for an effective risk assessment. This study aimed to determine the degradation profiles of 2,4-D and fipronil after controlled application in aquatic mesocosm systems under influencing factors such as environmental aspects and vinasse application, evaluate pesticide dissipation at the water-sediment interface, and perform an environmental risk assessment in water and sediment compartments. Mesocosm systems were divided into six different treatments, namely: control (C), vinasse application (V), 2,4-D application (D), fipronil application (F), mixture of 2,4-D and fipronil application (M), and mixture of 2,4-D and fipronil with vinasse application (MV). Pesticide application was performed according to typical Brazilian sugarcane management procedures, and the experimental systems were monitored for 150 days. Pesticide dissipation kinetics was modeled using first-order reaction models. The estimated half-life times of 2,4-D were 18.2 days for individual application, 50.2 days for combined application, and 9.6 days for combined application with vinasse. For fipronil, the respective half-life times were 11.7, 13.8, and 24.5 days. The dynamics of pesticides in surface waters resulted in the deposition of these compounds in the sediment. Also, fipronil transformation products fipronil-sulfide and fipronil-sulfone were quantified in water 21 days after pesticide application. Finally, performed risk assessments showed significant potential risk to environmental health, with RQ values for 2,4-D up to 1359 in freshwater and 98 in sediment, and RQ values for fipronil up to 22,078 in freshwater and 2582 in sediment.

Assessment of degradation mechanism of imidacloprid residues in grape rhizosphere soil by UHPLC-Orbitrap™-MS and its residual impact on soil enzyme activity

Imidacloprid (IM) is a systemic insecticide persistent in the environment and possesses a negative impact on the non-targeted ecosystem. The objective of the present study was to evaluate the dissipation and degradation mechanism of IM residues in grape rhizosphere soil and to investigate its residual effect on soil enzyme activity at different IM spiking levels. The half-life of IM residue in soil was 27, 36, and 43.5 days at a spiking level of 1, 10, and 50 mg kg-1, respectively following a bi-phasic first + first-order dissipation kinetics. UHPLC-Orbitrap™-MS analysis by targeted metabolomics approach revealed that IM metabolites such as IM-amine analogue, guanidine (reduction), 5-hydroxy IM (hydroxylation), IM-Urea (oxidation), reduced NO analogue of IM (oxidation), and olefin of guanidine IM (dehydrogenation) were identified and proposed the degradation mechanism in grape rhizosphere soil. Toxicity of IM residues on five extracellular enzymes, viz., dehydrogenase, acid phosphatase, alkaline phosphatase, β-glucosidase, and urease revealed that activity of dehydrogenase, acid phosphatase, and alkaline phosphatase remained unaffected at 60th day of sampling. The β-glucosidase and urease were negatively affected throughout the incubation period indicating the influence of IM residues on carbon and nitrogen mineralization in soil. Thus, long-term exposure of IM to grape rhizosphere through soil drenching could affect soil enzyme activity which has a negative effect on the soil nutrient cycle and soil microbiome.

Dissipation behavior and dietary risk assessment of cyclaniliprole and its metabolite in cabbage under field conditions

Cyclaniliprole, a novel diamide insecticide, can successfully control Spodoptera litura (Fabricius, 1775) in cabbage. Understanding the residual level of cyclaniliprole in crops and the risk related to its dietary intake is imperative for safe application. Here, we established a simplified, sensitive method for simultaneous analysis of cyclaniliprole and its metabolite NK-1375 (3-bromo-2-((2-bromo-4H-pyrazolo[1,5-d]pyrido[3,2-b]-[1,4]oxazin-4-ylidene)amino)-5-chloro-N-(1-cyclopropylethyl)benzamide) in cabbage by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate their dissipation behavior and residual characteristics. Cyclaniliprole showed rapid dissipation in cabbage and had a half-life of 1.8-2.7 days. The highest residue of total cyclaniliprole (sum of cyclaniliprole and NK-1375) in cabbage from different pre-harvest intervals (3 and 5 days) was 0.25 mg/kg. Our results confirmed the generally low dietary risk quotient of cyclaniliprole (0.243-1.036%) among different age and gender groups in China. Therefore, cyclaniliprole did not pose an unacceptable risk to consumers. This study contributes to setting cyclaniliprole maximum residue limit in cabbage by assessing its dissipation fate and food safety risks.

Dissipation kinetics, decontamination, consumer risk assessment and monitoring of flonicamid and imidacloprid residues in capsicum under open field and polyhouse condition

Liquid chromatography mass spectrometry (LC-MS)-based detection of flonicamid, imidacloprid and 6-chloronicotinic acid residues was validated and analysed in capsicum fruit, processed products and soil. The standard concentrations (0.0025 to 0.25 μg mL-1) of insecticides had a good linear curve (r2>0.99). Limit of detection and limit of quantification values were 0.0025 and 0.01 mg kg-1, respectively. The accuracy (80.53 to 100.33 %) of capsicum matrices and soil (89.41 to 100.52 %) and precision (RSD <10%) were established. Dissipation of imidacloprid (20 and 40 g a.i. ha-1) and flonicamid (75 and 150 g a.i. ha-1) at single (X) and double dose (2X) was studied under open field and polyhouse conditions. Under open field conditions, the flonicamid and imidacloprid residues persisted with half-life of 1.98, 2.90 days (X) and 2.80, 3.14 (2X) days, respectively. While under polyhouse conditions, the flonicamid and imidacloprid residues persisted with a half-life of 2.84, 3.66 (X) and 3.24, 3.97 (2X) days, respectively. The metabolite, 6-CNA, was not detected in any samples under open field and polyhouse condition. Among decontamination treatments, cooking in boiling water for 10 minutes reduced 78 to 81.60 percent of imidacloprid and flonicamid residues in both doses. The estimated dietary risk assessment of imidacloprid and flonicamid residues (RQ <1) indicated that the risk is within the acceptable limit. In farmgate capsicum samples, residues of flonicamid (7 samples) and imidacloprid (11 samples) were detected. Market samples of capsicum products (powder, flakes and sauce) were not detected with residues of selected insecticides.

Residue behaviors, degradation, processing factors, and risk assessment of pesticides in citrus from field to product processing

Pesticide residues in citrus may cause health risks in related juice products, and bring much uncertainty during the processing procedures. In this study, based on the dispersive solid-phase extraction (d-SPE) and UPLC-MS/MS, the residual levels of ten analytes in citrus and its processed products were monitored. The results showed that dissipation of the pesticides followed the first-order kinetics and the half-lives in citrus varied greatly, ranging from 6.36 to 63.0 days. The terminal residues of the five pesticides at harvest time were <0.01-0.302 and <0.01-0.124 mg/kg in raw citrus and citrus flesh, respectively, all of which were lower than the corresponding maximum residue limits (MRLs) of 0.5-1 mg/kg. In the processing experiments, the residues of ten analytes in sterilized juice, concentrated juice, and citrus essential oil were in the range of <0.01 to 0.442 mg/kg, <0.01 to 1.16 mg/kg, and <0.01 to 44.0 mg/kg, respectively, and the corresponding processing factors (PFs) were 0.127-1.00, 0.023-3.06, and 0.006-39.2. Particularly, in citrus essential oil, the PFs of etoxazole, fluazinam, lufenuron and spirotetramat-keto-hydroxy were 1.68-39.2, exhibiting obvious enrichment effects. By integrating the residue data of the field trials and the PFs, the acute and chronic dietary risks of the target pesticides in citrus juice were 0.031-1.83 % and 0.002-2.51 %, respectively, which were far lower than 100 %, demonstrating no unacceptable risk to human health. This work provides basic data for the establishment of the MRLs and dietary exposure risk assessment for processed citrus products.

The Dissipation Behavior and Risk Assessment of Carbendazim Under Individual and Joint Applications on Peach (Amygdalus persica L.)

Dissipation, residue levels, and ingestion risks of carbendazim in peach (Amygdalus persica L.) were investigated with individual and joint applications in the present study. The dissipation kinetics of carbendazim, chlorpyrifos, prochloraz, and imidacloprid were evaluated by the first-order kinetics. When carbendazim was individually applied, the final residual concentration was 2.97 mg kg-1 and the half-life was 17.4 d. In the joint application of carbendazim with chlorpyrifos, prochloraz, and imidacloprid, the residual concentrations at 35 d after spraying were 7.16, 7.50, and 4.26 mg kg-1 and the half-lives were 30.8, 23.7, and 23.2 d, respectively, which showed an increase of 1.3-1.8 times compared with the single application of carbendazim. In addition, the effects of household processing of rinsing and peeling were investigated, and a high removal rate of 54.6% and 76.5% were found. Furthermore, the carbendazim ingestion risk assessment was conducted, which indicated that the acute health risk (aHI) and hazard quotient (HQ) of carbendazim were all within acceptable levels ranging from 21.7% to 40.9%. However, a higher ingestion risk of carbendazim was found under the joint application. This study provides some preliminary guidance for the joint application and risk assessment of carbendazim in peach, which is worth further investigation.

Interactions of anthelmintic veterinary drugs with the soil microbiota: Toxicity or enhanced biodegradation?

Anthelmintic (AH) compounds are used to control gastrointestinal nematodes (GINs) in livestock production. They are only partially metabolized in animals ending in animal excreta whose use as manures leads to AH dispersal in agricultural soils. Once in soil, AHs interact with soil microorganisms, with the outcome being either detrimental, or beneficial. We aimed to disentangle the mechanisms of these complex interactions. Two soils previously identified as « fast » or « slow», regarding the degradation of albendazole (ABZ), ivermectin (IVM), and eprinomectin (EPM), were subjected to repeated applications at two dose rates (1, 2 mg kg-1and 10, 20 mg kg-1). We hypothesized that this application scheme will lead to enhanced biodegradation in «fast » soils and accumulation and toxicity in «slow » soils. Repeated application of ABZ resulted in different transformation pathways in the two soils and a clear acceleration of its degradation in the «fast » soil only. In contrast residues of IVM and EPM accumulated in both soils. ABZ was the sole AH that induced a consistent reduction in the abundance of total fungi and crenarchaea. In addition, inhibition of nitrification and reduction in the abundance of ammonia-oxidizing bacteria (AOB) and archaea (AOA) by all AHs was observed, while commamox bacteria were less responsive. Amplicon sequencing analysis showed dose-depended shifts in the diversity of bacteria, fungi, and protists in response to AHs application. ABZ presented the most consistent effect on the abundance and diversity of most microbial groups. Our findings provide first evidence for the unexpected toxicity of AHs on key soil microbial groups that might have to be considered in a regulatory context.

Spontaneous symmetry breaking and localization in nonequilibrium steady states of interactive quantum systems

The time evolution of a physical system is generally described by a differential equation, which can be solved numerically by adopting a difference scheme with space-time discretization. This discretization, as a numerical artifact, results in accumulated errors during evolution and thus usually plays a negative role in simulations. In a quantum circuit, however, the "evolution time" is represented by the depth of the circuit layer, and thus is intrinsically discrete. Hence, the discretization-induced error therein is not a numerical artifact, but a physical observable effect responsible for remarkable nonequilibrium phenomena absent in conventional quantum dynamics. In this paper, we show that the combination of measurement feedback and temporal discretization can give rise to a new type of quantum dynamics. As physical consequences of this interactive quantum dynamics, a nonequilibrium steady state with spontaneous symmetry breaking is revealed in a zero-dimensional (single-qubit) system. A localization mechanism distinct from that in the well-established Anderson localization has also been proposed in a one-dimensional interactive quantum system.

The Dissipation Kinetics, Residue Level and Dietary Risk of Kresoxim-Methyl in Rosa roxburghii and Soil Based on the QuEChERS Method Coupled with LC-MS/MS

This study aimed to investigate the dissipation, residues and dietary assessment of kresoxim-methyl in the application of Rosa Roxburghii and soil field using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The results show that kresoxim-methyl in R. roxburghii samples was extracted by acetonitrile and purified by ethyl enediamine-N-propylsilane (PSA), while kresoxim-methyl in soil samples was extracted by acetonitrile and purified by octadecylsilyl solid phase dispersant (C18). 0.1% formic acid (v/v)-water-methanol solution was used as the mobile phase, LC-MS/MS exhibited a good linearity in the range of 0.001-10 mg L-1. The recoveries of R. roxburghii and soil matrix were 82.48%-102.55%, and the relative standard deviation (RSD) were 1.13%-4.21%. The limit of detection (LOD) and quantification (LOQ) of kresoxim-methyl in R. roxburghii and soil samples was 0.50 and 0.60 µg kg-1, respectively. The dissipation dynamics of kresoxim-methyl in R. roxburghii and soil followed the first-order kinetics, with the half-life of 4.28 and 4.41 days, respectively. The terminal residual amount of kresoxim-methyl in R. roxburghii and soil samples was 0.003-1.764 and 0.007-2.091 mg kg-1, respectively. The dietary intake risk assessment indicates that a risk quotient (RQ) for kresoxim-methyl based on the national estimated daily intake (NEDI) of 0.1995 mg was 0.79%, suggesting that the use of kresoxim-methyl on R. roxburghii at recommended dosage was safe to consumers. This study provides the theoretical basis for guiding the rational use of kresoxim-methyl in the production of R. roxburghii.

Residue dynamics and dietary risk assessment of new formulation of novaluron and lambda cyhalothrin on tomato

Presence of residues on food commodities is major bottleneck of insecticide use under good agricultural practices (GAPs). The use of less persistent with two different mode of action insecticide is novel approach of getting maximum insect control without developing insecticide resistance. Novaluron, an insect growth disruptor and lambda cyhalothrin, a nerve poison has been used widely for the management of lepidopteran pests. Dissipation and consumer risk analysis studies were carried out on a new combination product of novaluron and lambda cyhalothrin are used for control insects of tomato at recommended standard dose of 71 + 14 g/ha and double dose of 142 + 28 g/ha of active ingredients. Extraction and cleanup of sample residues was done using QuEChERS technique and analyzed in GC-ECD. The residues of novaluron were dissipated within 10 to 15 days, and the residues of lambda cyhalothrin were at 7 to 10 days, both at the standard and double the standard dose, following a first order reaction kinetics. Analysis of risk and hazard quotient revealed that the test insecticides do not pose any dietary risk to consumer as TMDI < MPI and HQ < 1.

Non-similar solution development for entropy optimized flow of Jeffrey liquid

Mixed convection in dissipative entropy optimized stagnation point flow of nanomaterial towards stretching Riga sheet is addressed. Brownian and thermophoresis diffusions for nanomaterial are accounted. Constitutive relations for Jeffrey material are utilized. Non-similar solutions for the governing differential systems are developed. OHAM is employed for the convergent series solutions development. Outcomes of pertinent variables on flow quantities of interest are graphically organized. Finally the concluding remarks are arranged.

Dissipation patterns, residue analysis, and risk evaluation of hexaflumuron in turnip and cauliflower under Chinese growth conditions

Hexaflumuron has been globally registered over 2 decades to control the pests in brassicaceous vegetables, while data on its dissipation and residues in turnip and cauliflower is scarce. Herein, field trials were carried out at six representative experimental sites to study the dissipation behaviors and terminal residues of hexaflumuron in turnip and cauliflower. The residual amounts of hexaflumuron were extracted using a modified QuEChERS and analyzed with liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), the chronic dietary risk to Chinese populations was evaluated, and the maximum residue limit (MRL) in cauliflower, turnip tubers, and turnip leaves was calculated by the OECD MRL calculator. The single first-order kinetics model was the best-fitted kinetics model for hexaflumuron dissipation in cauliflower. The indeterminate order rate equation and first-order multi-compartment kinetic model were the best formulae for hexaflumuron dissipation in turnip leaves. The half-lives of hexaflumuron ranged from 0.686 to 1.35 and 2.41 to 6.71 days in cauliflower and turnip leaves, respectively. The terminal residues of hexaflumuron in turnip leaves of 0.321-9.59 mg/kg were much higher than in turnip tubers of < 0.01-0.708 mg/kg and cauliflower of < 0.01-1.49 mg/kg at sampling intervals of 0, 5, 7, and 10 days. The chronic dietary risk of hexaflumuron in the preharvest interval of 7 days was lower than 100% and much higher than 0.01%, indicating acceptable but nonnegligible health hazards for Chinese consumers. Therefore, MRL values of hexaflumuron were proposed as 2, 0.8, and 10 mg/kg in cauliflower, turnip tubers, and turnip leaves, respectively.

Bioremediation of the synthetic musk compounds Galaxolide and Tonalide by white rot fungal strain-assisted phytoremediation in biosolid-amended soil

The study was aimed to conduct the bioremediation of synthetic musks by four species of white rot fungi combined with phytoremediation (Zea mays) in biosolid-amended soils where only Galaxolide (HHCB) and Tonalide (AHTN) were found as other musks were below the detection limit (0.5-2 μg/kg dw). The HHCB and AHTN concentration in natural attenuation treated soil was decreased by not more than 9%. In solely mycoremediation, Pleurotus ostreatus was found to be the most efficient fungal strain, with the higher (P < 0.05) HHCB and AHTN removal (51.3% and 46.4%). Phytoremediation-only of biosolid-amended soil was also able to remove HHCB and AHTN from soil significantly (P < 0.05) in comparison to the control treatment without plants which resulted in the final concentration for both compounds of 56.2 and 15.3 μg/kg dw, respectively. Using white rot fungus-assisted phytoremediation, only P. ostreatus decreased the HHCB content in soil significantly (P < 0.05) by 44.7%, when compared to the initial concentration. While using Phanerochaete chrysosporium, the AHTN concentration was decreased by 34.5%, which was a significantly lower concentration at the end of experiment compared to the initial value. Via fungus-assisted phytoremediation, the enzymatic activity and fungal biomass were increased, probably due to the presence of roots in association with the soil microbiome, in the process increasing the degradation of fragrances accordingly. This could lead to a higher (P < 0.05) AHTN removal in P. chrysosporium assisted phytoremediation. Estimated HHCB and AHTN bioaccumulation factors in maize were lower than 1, therefore no environmental risk would be posed.

Determination of imidacloprid in brinjal and okra fruits, decontamination and its dietary risk assessment

Brinjal and okra are being sprayed withdifferent formulations of imidacloprid which leads to significant deposition of residues on fruits. Here in this study, we validated a method that could detect the traces of imidacloprid residues in a short run time using LC-MS/MS. LOD of 0.001 and LOQ of 0.003 μg/g for brinjal and in compliance with the MRL (0.2 mg/kg). The recovery at different spiking levels recorded 89.67 to 115.55 with an RSDr range of 3.02 and 5.22%. For okra, 0.0025 and 0.008 μg/g were observed as LOD and LOQ, respectively. Recovery was obtained between 88.69 and 93.74%. Precision in terms of repeatability (RSDr) and reproducibility (RSDwR) was found satisfactory in both matrices. Two applications of imidacloprid 17.8% SL in both vegetables showed faster dissipation initially and persisted up to 15-25 days. Decontamination with 2% salt solution followed by boiling for 15min. removed 96.43 and 73.66% of imidacloprid residues from brinjal and okra, respectively. Risk assessment was found to be less than one (HI < 1) for brinjal and okra matrix and can be safely consumed.

Method validation and dissipation kinetics of the novel HPPD-inhibiting herbicide cypyrafluone in winter wheat using QuEChERS method coupled with UPLC-MS/MS

Cypyrafluone, a novel hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide, can successfully control a wide species of grass and broadleaf weed in wheat fields. However, the dissipation behaviors and terminal residues of cypyrafluone in wheat fields remain unclear. Here, a simple, accurate, and dependable approach for the analysis of cypyrafluone in soil, wheat plant, and grain was constructed utilizing an adapted QuEChERS extraction combined with UPLC-MS/MS. For accurate quantification, matrix-matched calibrations with high linearity (R² >0.99) were employed to eliminate matrix interference. The method possessed high accuracy with recoveries in the range of 85.5%- 100.6% and precision with relative standard deviations < 14.3%, as well as high sensitivity with limits of quantifications of 0.001 mg kg^-1 in the three matrixes. The dissipation kinetics and terminal residues of cypyrafluone were determined at two separate locations with different climates, soil types and cropping systems in 2018. The half-lives of cypyrafluone in soil and wheat plant were 1.47-1.55 d and 1.00-1.03 d, respectively. At harvest, the terminal residue values of cypyrafluone detected in wheat plants were 0-0.0025 mg kg^-1 and 0.0044-0.0057 mg kg^-1 at the recommended dose and 1.5 times of the recommended dose, respectively, and 0.0049 mg kg^-1 of this herbicide was detected in grain at 1.5 times of the recommended dose, which was below the maximum residue limit (MRL). Finally, the risk quotient for cypyrafluone ranged from 0.33% to 0.81% (<1) for different age groups in China, indicating that the impact of residues from the cypyrafluone application on wheat was acceptable. These findings above will offer scientific guidelines for cypyrafluone application in the wheat field ecosystem.

Dissipation, metabolism, accumulation, processing and risk assessment of fluxapyroxad in cucumber and cowpea vegetables from field to table

Understanding the residue fate of fluxapyroxad is critical for food safety and human health. The present study profiled the dissipation, metabolism, accumulation, removal and risk assessment of fluxapyroxad in cucumbers and cowpeas from field to table. Greenhouse-field trials suggested that fluxapyroxad dissipated faster in cucumbers than in cowpeas, and M700F008 was the only detected metabolite at <LOQ-37.92 μg/kg. Fluxapyroxad accumulated in cucumbers (average residue accumulation value, 1: 2.21: 1.16) and cowpeas (1: 1.33: 1.05) after repeated spraying. Peeling, washing and parboiling could remove fluxapyroxad from cucumbers and cowpeas (PF range, 0.16-0.85); however, fluxapyroxad was partly concentrated by stir-frying (PF range, 0.36-1.41). Moreover, fluxapyroxad residues increased with increasing pickling time. Chronic and acute risk assessments revealed that dietary exposure to fluxapyroxad was within the acceptable levels from cucumber and cowpea consumption. Given high residue levels and their potential accumulation, fluxapyroxad should be continuously monitored and assessed in the future.

Is a dissipation half-life of 5 years for chlordecone in soils of the French West Indies relevant?

Recently, Comte et al. (2022) re-examined the natural degradation of chlordecone (CLD) in the soils of the French West Indies (FWI) by introducing an additional 'dissipation parameter' into the WISORCH model developed by Cabidoche et al. (2009). Recent data sets of CLD concentrations in FWI soils obtained by Comte et al. enabled them optimizing the model parameters, resulting in significantly shorter estimates of pollution persistence than in the original model. Their conclusions jeopardize the paradigm of a very limited degradation of CLD in FWI soils, which may lead to an entire revision of the management of CLD contamination. However, we believe that their study is questionable on several important aspects. This includes potential biases in the data sets and in the modeling approach. It results in an inconsistency between the estimated dissipation half-life time (DT50) of five years that the authors determined for CLD and the fate of CLD in soil from the application period 1972-1993 until nowadays. Most importantly, a rapid dissipation of CLD in the field as proposed by Comte et al. is not sufficiently supported by data and estimates. Hence, the paradigm of long-term persistence of CLD in FWI soils is still to be considered.

Dissipation of penconazole formulation in horticultural crops by ultrahigh performance liquid chromatography-high resolution mass spectrometry: From the active substance to metabolites

The present study describes the dissipation and metabolism of penconazole in horticultural products by a method based on ultra-high performance liquid chromatography-quadrupole-orbitrap (UHPLC-Q-Orbitrap). Targeted and suspected analysis were carried out. Two independent trials were performed under laboratory conditions (on courgette samples), and under greenhouse conditions (on tomatoes) during 43 and 55 days, respectively. In both studies, a pesticide formulation (TOPAS® EW) containing penconazole was used. The results showed that penconazole was relatively short-lived (<30 days) in horticultural products. The proposed method allowed for the tentative identification and semi-quantification of nine metabolites. In addition, the potential toxicity of these metabolites was evaluated, observing that some of them are even more toxic than penconazole, as triazole lactic acid. This research may provide a starting point for understanding the dissipation process of penconazole, the formation pathways of its main metabolites, their concentrations and toxicity to ensure food safety and the environmental protection.

Chlorantraniliprole in foods: Determination, dissipation and decontamination

Chlorantraniliprole (CAP) is the first commercially available anthranilic diamide insecticide that targets ryanodine receptors. However, excessive use of CAP can lead to persistent contamination on treated foods and adverse effects on human wellness. The current review focuses on CAP residue analysis in foods by using chromatographic techniques. QuEChERS (quick, easy, cheap, effective, rugged and safe) is the most widely used sample preparation strategy and liquid chromatography tandem mass spectrometry is the predominant analytical method for various food matrices including vegetable, fruit, grain, fish and so on. Moreover, this review summarizes the dissipation pattern of CAP on foods and found it usually dissipates fast on plant in open-field environment. For decontamination, common culinary cleaning methods could effectively remove CAP from vegetables. Finally, some new directions are proposed for better advancement.

Effect of composted pig manure, biochar, and their combination on antibiotic resistome dissipation in swine wastewater-treated soil

The prevalence of antibiotic resistance genes (ARGs), owing to irrigation using untreated swine wastewater, in vegetable-cultivated soils around swine farms poses severe threats to human health. Furthermore, at the field scale, the remediation of such soils is still challenging. Therefore, here, we performed field-scale experiments involving the cultivation of Brassica pekinensis in a swine wastewater-treated soil amended with composted pig manure, biochar, or their combination. Specifically, the ARG and mobile genetic element (MGE) profiles of bulk soil (BS), rhizosphere soil (RS), and root endophyte (RE) samples were examined using high-throughput quantitative polymerase chain reaction. In total, 117 ARGs and 22 MGEs were detected. Moreover, we observed that soil amendment using composted pig manure, biochar, or their combination decreased the absolute abundance of ARGs in BS and RE after 90 days of treatment. However, the decrease in the abundance of ARGs in RS was not significant. We also observed that the manure and biochar co-application showed a minimal synergistic effect. To clarify this observation, we performed network and Spearman correlation analyses and used structure equation models to explore the correlations among ARGs, MGEs, bacterial composition, and soil properties. The results revealed that the soil amendments reduced the abundances of MGEs and potential ARG-carrying bacteria. Additionally, weakened horizontal gene transfer was responsible for the dissipation of ARGs. Thus, our results indicate that composted manure application, with or without biochar, is a useful strategy for soil nutrient supplementation and alleviating farmland ARG pollution, providing a justification for using an alternative to the common agricultural practice of treating the soil using only untreated swine wastewater. Additionally, our results are important in the context of soil health for sustainable agriculture.

Dissipation kinetics of co-formulation with two herbicides, clodinafop-propargyl and oxyfluorfen, in/on onion (Allium cepa) samples

Supervised field trail on dissipation of co-formulation with herbicides clodinafop-propargyl and oxyfluorfen in spring onion showed similar pattern of dissipation during two different seasons. Residues of clodinafop-propargyl reached ≤ limit of quantitation (LOQ, 0.05 mg kg^-1) on 3rd day after application at both standard and double dose during both the seasons. Oxyfluorfen residues followed first-order kinetics in both the doses during first season with half-life of 0.81 to 3.14 days. The residues of clodinafop-propargyl were detected in soil at both the doses during first season. However, residues were ≤ LOQ (0.05 mg kg^-1) during second season. The residues of oxyfluorfen were detected only in double dose during first season in soil. In all other cases and in onion bulb, residues were ≤ LOQ (0.05 mg kg^-1) at the time of harvest. As the residues were either ≤ LOQ (0.05 mg kg^-1) on 3rd day or have a half-life of 3.14 days, the co-formulation can be used safely, provided a pre harvest interval (PHI) of 3 days is followed. On the basis of maximum residue limits (MRLs) in other commodities and from the data of present study, a default MRL of 0.05 mg kg^-1 is proposed for both the pesticides.

Residues and dietary risk assessment of fluazinam in root mustard after field experiments

The residue levels of fluazinam in root mustard were investigated by using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) technique with ultra-performance liquid chromatography tandem mass spectrometry. Samples of leaf and root mustard were analyzed. The recoveries of fluazinam were 85.2-110.8% for leaf mustard with the coefficient of variation of 1.0-7.2%, and 88.8-93.3% for root mustard with the coefficient of variation of 1.9-12.4%. The suspension concentrate formulation of fluazinam was applied on root mustard at 262.5 g a.i. ha^-1 in accordance with good agricultural practice (GAP), respectively. After the final application, the root mustard samples were collected at 3, 7, and 14 days. Fluazinam residues in root mustard were less than 0.01-0.493 mg kg^-1. The dietary risk of fluazinam was predicted by comparing intake amounts with the toxicological data, namely acceptable daily intake (ADI) and acute reference dose (ARfD). The risk quotient (RQ) was 72.2-74.3%, for ordinary consumers, which showed negligible risk. According to the maximum residue limit (MRL) and dietary risk assessment, it is suggested that the pre-harvest interval (PHI) of 3 days; meanwhile, the MRL of 2 mg kg^-1 was suggested for fluazinam in root mustard, which indicates that the dietary risk of fluazinam 500 g L^-1 suspension concentrate (SC) with the recommended usage on root mustard is negligible. This study provided basic data on the use and safety of fluazinam in root mustard to help the Chinese government formulate a maximum residue level for fluazinam in root mustard.

Comparative analysis of remediation efficiency and ultrastructural translocalization of polycyclic aromatic hydrocarbons in Medicago sativa, Helianthus annuus, and Tagetes erecta

Polycyclic aromatic hydrocarbons (PAHs) are semi-volatile anthropogenic contaminants that can damage soil fertility and threaten the environment due to their hazardous effects on various ecological parameters. The experimental objective was divided into two parts because PAHs are always present in mixtures. The toxicity of anthracene, phenanthrene, pyrene, and fluoranthene was examined and investigated the potential of three phytoremediator plants species viz Tagetes erecta, Helianthus annuus, and Medicago sativa for remediation and translocation of individual PAH. PAHs were shown to have inhibitory or stimulating effects on growth, antioxidant properties, and impact on the structure of plant cells. The result showed that M. sativa significantly enhances the removal rate of PAHs in the soil. The dissipation rate reached 96.2% in M. sativa planted soil, followed by H. annuus and T. erecta. Among the plant species, M. sativa exhibited the highest root and shoot concentrations (314.37 and 169.55 mg kg-1), while the lowest concentration was 187.56 and 76.60 mg kg-1 in T. erecta. SEM-EDX and fluorescence micrographs confirmed that pyrene altered plant tissue's ultrastructure and cell viability and was found to be the most toxic and resistant. M. sativa was proven to be the most effective plant for the mitigation of PAHs.

Persistent toxicity and dissipation dynamics of afidopyropen against the green peach aphid Myzus persicae (Sulzer) in cabbage and chili

The green peach aphid, Myzus persicae (Sulzer), is a significant global pest in horticultural and field crops. Afidopyropen is a novel systemic insecticide with high efficacy against sucking pests, and it is suitable for the management of M. persicae. However, the persistent toxicity and dissipation dynamics of afidopyropen in vegetables remain unknown. In this study, we determined the residual activity and dissipation dynamics of afidopyropen against M. persicae on cabbage and chili. The data showed that the toxicity of afidopyropen against M. persicae lasted more than 30 days; the corrected mortality was greater than 80% 10 days after application and was 50-60% 30 days post-application. The afidopyropen residues on cabbage and chili plants were quantified using ultrahigh-pressure liquid chromatography-tandem mass spectrometry. The dissipation half-lives of afidopyropen on cabbage and chili plants ranged from 1.45 to 2.34 days and 3.98-5.98 days at different recommended dosages, respectively. Our findings provide valuable data for the maximum residue limits of afidopyropen on vegetables and will help growers determine the frequency and timing of its application on cabbage and chili.

Dissipation, uptake, translocation and accumulation of five phthalic acid esters in sediment-Zizania latifolia system

The dissipation, uptake, translocation and accumulation of phthalic acid esters (PAEs) including diallyl phthalate (DAP), diisobutyl phthalate (DIBP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP) and di-(2-ethylhexyl) phthalate (DEHP) in sediment-Zizania latifolia system were investigated by gas chromatography-flame ionization detector after a QuEChERS pretreatment method. The dissipation rates of PAEs in sediment were positively correlated with exposure time, and more than 68.12% of PAEs in sediment were decreased after 28 d even when the spiked contents were extremely high. All the five PAEs could be taken up by roots from contaminated sediment and subsequently be transported into stems and leaves. There were significant linear correlations between the sediment content and the content in each tissue. DEHP was most readily transported from sediment to roots and stems, followed by BBP, DBP, DIBP and DAP, whereas the order of transportation from roots to leaves was reversed. During 28 d of exposure, the average concentration of each PAE in stems was the highest, followed by roots, leaves and edible parts. DEHP and BBP were the major contaminants in edible parts but could not pose a risk to human health. The accumulation of PAEs in edible parts was influenced by the species and concentration of PAEs as well as the survival time and harvest time of edible parts. The differences in uptake and translocation behaviors among PAEs in plant tissues were significantly correlated to their physicochemical properties, such as alkyl chain length and octanol/water partition coefficient (logK_ow). The results reveal that Zizania latifolia is not only a kind of safe food, but also a potential plant to remediate contaminated sediment by accumulating and degrading PAEs from the habitats.

Dissipation dynamics and comparative dietary exposure assessment of mefentrifluconazole in rice

A fast and sensitive analytical method based on UHPLC coupled with tandem mass spectrometry was established to investigate the dissipation and final residual amounts of mefentrifluconazole in rice, and dietary risk to consumers was evaluated. The method provided good linearity (R² ≥ 0.9979), accuracy (recovery range, 79.0-101.5%), precision (relative standard deviation range, 1.3-13.9%), and sensitivity (limit of quantification, 0.005 mg/kg). The dissipation dynamics of mefentrifluconazole in rice followed first-order kinetics, with half-lives of 2.8-16.6 days. The final residues of mefentrifluconazole in various samples of harvested brown rice ranged from less than the limit of quantification to 0.092 mg/kg, the latter value being higher than the maximum residue limit recommended by the European Union. Comparative dietary exposure of mefentrifluconazole was assessed using field data and Chinese dietary patterns for different genders, regions, and age data. Although the results showed acceptable levels of risk for both acute exposure (the percentage of the acute reference dose ≤ 0.7483%) and chronic dietary intake (the percentage of acceptable daily intake ≤ 31.8516%), more studies of children are needed because they are at higher risk than other groups. This work provides the necessary data for registering and establishing the maximum residue limit for mefentrifluconazole in rice in China and reveals the potential risks to different groups of long-term application of mefentrifluconazole to rice and other crops.

Effects of plant morphology, vitamin C, and other co-present pesticides on the deposition, dissipation, and metabolism of chlorothalonil in pakchoi

Pesticide residues have been a focus of attention of food safety. Different varietal pakchoi plants grown in open fields were studied to understand effects of morphology, leaf wax content, and vitamin C on the deposition, dissipation, and metabolism of chlorothalonil. The loose pakchoi plants and flat leaves were conducive to pesticide deposition, but not plants with erect leaves. Chlorothalonil on nine varieties of pakchoi dissipated in the first-order kinetic with T1/2 s of 1.4 ~ 2.0 days. Vitamin C in pakchoi could promote the dissipation of chlorothalonil. Carbendazim could significantly promote the dissipation of chlorothalonil on pakchoi. Interestingly, four metabolites of chlorothalonil were identified in the pakchoi and the metabolic pathway was predicted by DFT calculations. The risk assessment showed that pakchoi were safe for consumption after 10 days of application of the recommended dose. This work provides important information for the understanding of deposition, dissipation, and metabolism of chlorothalonil in pakchoi.

Dissipation and risk assessment of fluopyram and trifloxystrobin on onion by GC-MS/MS

The dissipation and risk assessment studies on fluopyram, trifloxystrobin and their metabolites were carried out on onion under field conditions after two treatments of fluopyram 250 g/L + trifloxystrobin 250 g/L SC @ 150 and 300 g a.i. ha^-1. The onion bulb samples were collected at 0, 3, 7, 14, and 21 days after second spray to study the pattern of dissipation using QuEChERS methodology for processing and analysis on GC-MS/MS. The total initial residues of fluopyram (fluopyram + fluopyram benzamide) in immature onion bulb were 2.14 and 4.93 mg kg^-1, at single and double dose, respectively. The residues of 0.02 and 0.06 mg kg^-1 persisted in the mature onion bulb collected at the harvest (30 days after treatment). The total initial residues of trifloxystrobin (trifloxystrobin + CGA 321113) in immature onion bulb were 0.65 and 1.97 mg kg^-1, at single and double dose, respectively, which reached < LOQ and 0.06 mg kg^-1 at the respective doses at the harvest time. Dissipation of fluopyram followed second-order kinetics with DT₅₀ values of 1.83 and 1.74 days, whereas trifloxystrobin followed first-order kinetics with DT₅₀ values of 4.73 and 4.78 days, at single and double dose respectively. Risk assessment in terms of hazard quotient was done to estimate the risk that can occur due to application of this combination pesticide. It was observed that even the spray at the double recommended dose could not have dietary risks on the consumers.

Effect of cold storage on Carbofuran dissipation in Cabbages (Brassica Oleracea)

Cabbage being a highly imported product is often subjected to long term cold storage to maintain product quality and in order to retain its freshness it is kept in cold chambers for a long time. Being highly infested by pests during storage, cabbages are often treated with insecticides having active ingredients such as carbofuran in them. Also, large number of malpractices have come into the notice of the regulatory bodies where the growers use last minute Carbofuran dips on the cabbage heads to improve the shine and lustre of the foliage for better marketability .Therefore, the study was conducted to monitor the effect of cold storage on degradation pattern of Carbofuran on Cabbage during storage in Kashmir valley. The level of carbofuran residue decreased with an increase in storage period Dissipation pattern was studied for three application rates of Carbofuran by dipping the samples in T1 (First dose) 3g/1000mL, T2 (Second dose) 2g/1000mL, T3 (Third dose) 1g/1000mL. The initial control deposit was found to be 0.05mg/kg for T1, 0.03mg/kg for T2, 0.01mg/kg for T3 on Cabbage. The residues were dissipated to about 0.02mg/kg in T1, 0.01mg/kg in T2 and ND in T3 after 60 days of application. The waiting period after proper risk assessment was calculated and was found to be 30 days for almost all application rates.

Effect of formulation on the indoxacarb and lufenuron dissipation in maize and risk assessment

The supervised field trials were conducted in maize crops using nano-microemulsion (NM) and a commercial formulation of indoxacarb and lufenuron to evaluate the effect of nano-formulation on the dissipation pattern. A modified QuEChERS (Quick Easy Cheap Effective Rugged and Safe)-UPLC-MS/MS (ultra-performance liquid chromatography tandem mass spectrometry) method was utilized for sample analysis. Results showed that the initial deposits of indoxacarb and lufenuron in plants using nano-microemulsion were 0.98 mg/kg and 8.18 mg/kg at recommended dosage, while using the commercial formulation, they were 0.85 mg/kg and 5.53 mg/kg, respectively. Moreover, half-life (t_1/2) values of using nano-microemulsion were 1.25 days and 2.51 days, which were shorter than indoxacarb (1.87 days) and lufenuron (3.00 days) from the commercial formulation, suggesting that pesticide formulations have a moderate impact on the initial deposit and dissipation rate. The terminal residue test showed that indoxacarb and lufenuron residues in maize grain and maize straw were below the available maximum residue limit (MRL, 0.01 mg/kg), suggesting 2% indoxacarb NM and 5% lufenuron NM are safe to use under the recommended dosage. The risk quotient value (RQ of indoxacarb and lufenuron equal to 17.7% and 2.4%, respectively) also revealed an acceptable risk for human consumption. These findings provide scientific evidence of the proper application of 2% indoxacarb NM and 5% lufenuron NM on maize crops.

Air-coupled ultrasonic diffuse-wave techniques to evaluate distributed cracking damage in concrete

In this study, we investigated the suitability of applying air-coupled ultrasonic diffuse-wave techniques to concrete structures for the evaluation of arbitrarily distributed micro-cracking damage. Air-coupled test results were compared with those obtained using a conventional full-contact measurement system. Three different micro-cracking damage levels were simulated by embedding varying amounts of low-stiffness polypropylene fibers in concrete samples. Two principal diffuse-wave parameters, diffusivity and dissipation, were determined using air-coupled and full-contact test configurations. Wave frequencies of 300-600 kHz were employed, which set up significant ultrasonic scattering owing to the heterogeneous characteristics of concrete components (e.g., aggregates, micro-cracks expressed by fibers, and pores). In addition, the sensitivities of diffusivity and dissipation to the number of measurement locations were examined. The results demonstrated that the air-coupled method can provide an equivalent reliability to the full-contact method, allowing a much faster and flexible data collection. The spatial averaging of 20 arbitrarily selected data (measured at different locations) yielded sufficiently accurate diffuse-wave parameters, showing less than a 5 % difference from the average of 32 spatially different data.

Dissipation rates, residue distribution, degradation products, and degradation pathway of sulfoxaflor in broccoli

Broccoli was selected as the research object in this paper to reveal the dissipation, distribution, and degradation pathway of sulfoxaflor under greenhouse and open-field cultivation conditions for the ecological risk assessment of sulfoxaflor. Results showed that the dissipation of sulfoxaflor in broccoli leaves, flowers, stems, roots, and the whole broccoli was in accordance with the first-order kinetic equation. The sulfoxaflor concentration in broccoli roots reached the maximum value after 1 day of application and then gradually decreased. The degradation half-lives of sulfoxaflor in the roots, leaves, flowers, stems, and whole broccoli were between 2.3 and 19.8 days. The longest degradation half-life of sulfoxaflor was in Heilongjiang under greenhouse cultivation. The terminal residue of sulfoxaflor in broccoli was in the range of 0.005-0.029 mg/kg, and the proportion of sulfoxaflor residue in broccoli leaves was the largest. Thirteen transformation products were separated and identified by ultrahigh-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and their kinetic evolution was studied. The cleavage of the N = S bond, C-S bond, C-O bond, and cyanide, as well as glucosylation, hydroxylation, SO extrusion, elimination, sulfhydrylation, ketonization, defluorination, and rearrangement, was inferred as the mechanism. Overall, these results can provide guidance for the supervision of the safe application of sulfoxaflor.

Dissipation and dietary exposure risk assessment of pyraclostrobin, fluxapyroxad, difenoconazole, and azoxystrobin in the Fritillaria field ecosystem

Fritillaria (Beimu in Chinese) is a well-known traditional Chinese medicinal herbal and valuable health food, which has attracted more and more attention. In this study, an efficient method was developed to determine pyraclostrobin, fluxapyroxad, difenoconazole, and azoxystrobin in plants, fresh Fritillaria, dry Fritillaria, and soil via liquid chromatography-tandem mass spectrometry. The average recoveries of the method were 78.9-109.7% with relative standard deviations of 0.94-11.1%. The dissipation half-lives of the four fungicides were 4.4-7.7 days in the Fritillaria plant and 11.6-18.2 days in the soil. The terminal residues of four fungicides were 0.033-0.13 mg/kg in fresh Fritillaria, 0.096-0.42 mg/kg in dry Fritillaria, and 0.12-0.74 mg/kg in soil. In the risk assessment of dietary exposure, all the chronic hazard quotient and acute hazard quotient index values were far below 100%, which were both acceptable to consumers. Accordingly, 7 days was recommended as the pre-harvest interval for the four fungicides in Fritillaria. This work could guide the safe use of these fungicides in Fritillaria and also give a reference for the Chinese government to establish the maximum residue limits (MRLs).

Plant contribution to the remediation of PAH-contaminated soil of Dagang Oilfield by Fire Phoenix

Pot experiments were conducted to evaluate plant contribution during remediation of the polycyclic aromatic hydrocarbons (PAH)-contaminated soil of Dagang Oilfield by Fire Phoenix (a mixture of Festuca L.). The results showed that Fire Phoenix could grow in soil contaminated by high and low concentrations of PAHs. After being planted for 150 days, the total removal rate of six PAHs in the high and low PAH concentrations was 80.36% and 79.79%, significantly higher than the 58.79% and 53.29% of the unplanted control group, respectively. Thus, Fire Phoenix can effectively repair the soil contaminated by different concentrations of PAHs. In high concentrations of PAHs, the results indicated a positive linear relationship between PAH absorption in tissues of Fire Phoenix and the growth time in the early stage. In contrast, the contents of PAHs were just slightly increased in the late period of plant growth. The main factor for the dissipation of PAHs was plant-promoted biodegradation (99.04%-99.93%), suggesting a low contribution of PAH uptake and transformation (0.07%-0.96%). The results revealed that Fire Phoenix did not remove the PAHs in the soil by accumulation but promoted PAH dissipation in the soil by stimulating the microbial metabolism in the rhizosphere.

Evidence for enhanced dissipation of chlorpyrifos in an agricultural soil inoculated with Serratia rubidaea strain ABS 10

The insecticide ¹⁴C-chlorpyrifos was found mineralized in a Tunisian soil with repeated exposure to it. From this soil, a bacterial strain was isolated that was able to grow in a minimal salt medium (MSM) supplemented with 25 mg L^-1 of chlorpyrifos. It was characterized as Serratia rubidaea strain ABS 10 using morphological and biochemical analyses, as well as 16S rRNA sequencing. In a liquid culture, the S. rubidaea strain ABS 10 was able to dissipate chlorpyrifos almost entirely within 48 h of incubation. Although the S. rubidaea strain ABS 10 was able to grow in an MSM supplemented with chlorpyrifos and dissipate it in a liquid culture, it was not able to mineralize ¹⁴C-chlorpyrifos. Therefore, it can be concluded that the dissipation capability of this bacteria might be attributed to its capacity to adsorb CHL. It can also be ascribed to other reasons such as the formation of biogenic non-extractable residues. In both non-sterile and sterile soil inoculated with S. rubidaea strain ABS 10, chlorpyrifos was more rapidly dissipated than in controls with DT₅₀ of 1.38 and 1.05 days, respectively.

Residue dynamics and bio-efficacy of triflumezopyrim against Nilaparvata lugens and non-targeted effect on natural enemies in a rice ecosystem

Triflumezopyrim (TMP), a mesoionic insecticide, is commonly used for controlling planthoppers in rice. However, the relationship between the TMP residue and toxicity against brown planthoppers (BPHs) has not been studied in detail. We are reporting the dissipation of TMP from rice plant and soil under field conditions. The median lethal dose and median lethal concentration were 0.036 ng per insect and 0.525 mg L-1, respectively. TMP at recommended dose (25 g a.i. ha-1) recorded 1.25 live BPH per hill as against 25.5 per hill in control at 14 days after treatment. TMP was considered to be harmless to the natural enemies, namely, Cyrtorhinus lividipennis and Lycosa pseudoannulata in the rice ecosystem. The residue of TMP from rice plant and soil was estimated using the QuEChERS method using three different doses (12.5, 25, and 50 g a.i. ha-1). The limit of quantitation (LOQ) of TMP in plant and soil was 5 µg kg-1 and 1 µg kg-1, respectively. The maximum content of TMP in soil was less than 1% that of plant content on day 1. The dissipation pattern of TMP both from plant and soil was better explained by the first-order double-exponential decay model (FODED) as compared to the first-order kinetic model. Overall, the half-lives of TMP were ranged from 2.21 to 3.02 days in plant tissues and 3.78 to 4.79 days in soil as per the FODED model. Based on the persistence and toxicity of TMP, we could conclude that TMP will be effective against BPH up to 7-10 days after application. Triflumezopyrim with reasonable persistence and high efficacy could be recommended as an alternate pesticide in BPH management in rice.

Emission estimation and prioritization of veterinary pharmaceuticals in manure slurries applied to soil

Veterinary pharmaceuticals (VPs) are emitted into the environment and transfer to groundwater and surface water is diffuse and complex, whereas actual information on the fate is frequently limited. For 17 VPs of potential concern in the Netherlands, we assessed sources and emission due to animal slurry applications to soil. Hence, we examined the use of VPs in four livestock sectors in the Netherlands for 2015-2018, and quantified animal excretion rates and dissipation during slurry storage. For almost all VPs, administrated quantities to the animals during the period 2015-2018 decreased. VP concentrations during a storage period of six months could decrease between 10 and 98% depending on the compound. Predicted concentrations of VPs in slurries after storage compared well with measured concentrations in the literature. Based on the storage model outcomes, we developed a residue indicator, that quantifies the potential for residues in applied slurry. This indicator agrees well with the most frequently detected VPs in the Dutch slurries, and is therefore useful to prioritize measures aiming at reducing VP emissions into the environment.

Simultaneous determination of dimethoate and its metabolite omethoate in curry leaf using LC-MS/MS and risk assessment

This study presents the method development, validation, and simultaneous determination of dimethoate and its metabolite omethoate in curry leaf. Samples were extracted following modified quick, easy, cheap, effective, rugged, and safe extraction protocol and analyzed using liquid chromatography-tandem mass spectrometry. The limit of quantification in the matrix was 0.005 μg g^-1 for dimethoate and omethoate. Extraction using acetonitrile recorded the average recoveries in the range of 82.25 to 112.97% for dimethoate and 85.57 to 107.22% for omethoate at 0.005, 0.025 and 0.050 μgg^-1 fortification levels and relative standard deviation less than 5%. Similarly, the relative standard deviation values for intraday (Repeatability) and interday (Reproducibility) tests were less than 15%. Dissipation kinetics of dimethoate 30% emulsifiable concentrate at 200 and 400 g a.i h^-1 recorded initial deposits of 5.20 and 10.05 μg g^-1 and 0.33 and 0.48 μg g^-1 for dimethoate and omethoate, respectively, and half-life of 3.07 and 3.34 days. The estimated hazard index value found more than one at a day after dimethoate application. It is not safe for consumer health to use curry leaves in the initial days after application. This article is protected by copyright. All rights reserved.

Dissipation pattern and dietary risk assessment of some commonly used insecticides on tomato (Solanum lycopersicum L.)

Pesticide residue in food commodities is a serious concern in relation to the consumer safety and also the most significant barrier in the trade of food commodities. The dissipation pattern of four insecticides viz., novaluron, λ-cyhalothrin, imidacloprid, and fenazaquin was evaluated on tomato fruits and cropped soil. The residues were extracted using the QuEChERS analytical method and quantized using GC-ECD, GC-MS, and HPLC-PDA. The analytical method was validated using parameters like recovery, linearity, accuracy, matrix effect, specificity with limit of detection and limit of quantitation established to be 0.01 and 0.05 mg kg-1, respectively for all the pesticides. The average initial deposits (samples collected after two hours of spray) at recommended dose of novaluron, λ-cyhalothrin, imidacloprid and fenazaquin were 0.593, 0.293, 0.227 and 0.431 mg kg-1 on tomato fruits, respectively and were below the limit of quantification in soil. The pre-harvest interval of 17, 8, 1 and 13 days were suggested for novaluron, λ-cyhalothrin, imidacloprid and fenazaquin on tomato, respectively. The risk assessment studies revealed that all pesticides under study are safe and did not pose any threat to humans as (TMDI) theoretical maximum dietary intake is less than maximum permissible intake (MPI) and acceptable daily intake (ADI).

Enantioselective evaluation of the chiral fungicide mandipropamid: Dissipation, distribution and potential dietary intake risk in tomato, cucumber, Chinese cabbage and cowpea

A chiral analytical method was developed and validated for the determination of mandipropamid enantiomers in tomato, cucumber, Chinese cabbage and cowpea. The linearity (R² > 0.99), accuracy (recovery: 73.8-106%) and precision (relative standard deviation: < 11%) were adequate for the detection of mandipropamid enantiomers in four vegetables. Field trials were further conducted to investigate the dissipation and residue distribution of mandipropamid and the possible enantioselectivity in different vegetables. Due to the shorter half-lives, mandipropamid dissipated more rapidly in Chinese cabbage (1.8-2.0 d) and cowpea (1.6-2.4 d) than in tomato (5.0-8.4 d) and cucumber (2.4-5.5 d). The residues of mandipropamid were 45-179 µg/kg in tomato 14 d at low dose, 48-98 µg/kg in cucumber 7 d after spraying twice at low dose, and < 2.5-1942 µg/kg in Chinese cabbage and cowpea in all treatments, which were below the maximum residue limits of mandipropamid set by the European Union and Codex Alimentarius Commission. Enantioselectivity was observed during the mandipropamid dissipation process in four vegetables. The S-(+)-enantiomer dissipated more rapidly than the R-(-)-enantiomer in tomato and Chinese cabbage (enantiomeric fractions > 0.5). For cucumber and cowpea, the dissipation of the R-enantiomer was preferential (enantiomeric fractions < 0.5). According to the risk quotient data (<< 100%), the residues of mandipropamid in four vegetables were safe for Chinese consumers. This study could provide useful information for the dissipation fate and residue distribution of mandipropamid in vegetables at the enantiomer level and offer some guidance for the dietary intake risk evaluation of mandipropamid in vegetables.