Residue levels, processing factors and risk assessment of pesticides in ginger from market to table.

Ginger is consumed as a spice and medicine globally. However, pesticide residues in ginger and their residue changes during processing remain poorly understood. Our results demonstrate that clothianidin, carbendazim and imidacloprid were the top detected pesticides in 152 ginger samples with detection rates of 17.11-27.63%, and these pesticides had higher average residues of 44.07-97.63 µg/kg. Although most samples contained low levels of pesticides, 66.45% of the samples were detected with pesticides, and 38.82% were contaminated with 2-5 pesticides. Peeling, washing, boiling and pickling removed different amounts of pesticides from ginger (processing factor range: 0.06-1.56, most <1). By contrast, pesticide residues were concentrated by stir-frying and drying (0.50-6.45, most >1). Pesticide residues were influenced by pesticide physico-chemical parameters involving molecular weight, melting point, degradation point and octanol-water partition coefficient by different ginger processing methods. Chronic and acute dietary risk assessments suggest that dietary exposure to pesticides from ginger consumption was within acceptable levels for the general population. This study sheds light on pesticide residues in ginger from market to processing and is of theoretical and practical value for ensuring ginger quality and safety.

Toxicity assessment of a novel biopesticide guvermectin and identification of its transformation products in soils.

Guvermectin is a novel biopesticide often used as seed soaking to promote the rice yield. However, its biotoxicity and degradation behavior in soils were still not disclosed, which posed a knowledge gap to guide its rational application. Therefore, the degradation behaviors of guvermectin in four typical soils under aerobic and anaerobic conditions were investigated in the laboratory. The results showed that guvermectin was degraded fast with DT50 ranging from 0.95 to 10.10 d, and the degradation rate was higher in aerobic condition than that in anaerobic condition. Eight transformation products were screened using UPLC-QTOF/MS. The acute toxicities tests of guvermectin to Coturnix coturnix japonica and Apis mellifera were measured by biological laboratory experiments, and the acute and chronic toxicities of transformation products to Danio rerio, Daphnia magna Straus and Green algae were predicted by ECOSAR software. The results showed that guvermectin has low toxic to quail and honeybee (LD50 2000 mg a.i./kg body weight, LD50 Ëƒ 100 µg a.i./bee), and its transformation products were also low toxic class to Danio rerio, Daphnia magna Straus and Green algae (LC50/EC50 > 100 mg a.i./L). However, the nucleoside-like metabolites may pose a potential risk due to their similarity to genetic material, which should be concerned. The findings provided important environmental risk assessment data for the rational use of guvermectin.

Assessment on the stereoselective behavior of cyflumetofen to earthworms (Eisenia foetida): Degradation, bioaccumulation, toxicity mechanism, and metabolites.

In this study, environmental behavior and toxicity of cyflumetofen (CYF) enantiomers were evaluated comprehensively in a soil-earthworm system. In the earthworm (Eisenia foetida), (+)-CYF was preferentially accumulated, and acute toxicity of Rac-CYF was greater than that of (+)-CYF and (-)-CYF, indicating that the combination of CYF enantiomers increased the toxicity. As a measure of chronic toxicity, compared with (-)-CYF-treated earthworms, malondialdehyde accumulation was higher in (+)-CYF-treated earthworms, indicating a more severe oxidative stress response. In a DNA comet plot, the trailing distance in the (+)-CYF treatment was 1.97 times greater than that in the (-)-CYF-treated, revealing more severe genotoxicity with (+)-CYF. However, (-)-CYF was more likely than (+)-CYF to activate the earthworm detoxification enzyme pathway. With (+)-CYF treatment, the number of differentially expressed genes (DEGs) involved in the pathogenic pathway increased significantly, whereas with (-)-CYF-treatment, more DEGs were involved in P450 and glutathione S-transferase (GST) detoxification metabolic pathways, including high expression of the genes chi-III, GST-S-1, and GST-alpha-5. The main metabolites of the CYF enantiomers were A-2, A-12, B-1, AB-1, AB-7, and B-3, which exhibited potential ecotoxicity. In general, CYF was stereoselective in the soil-earthworm ecosystem, with (+)-CYF causing a higher genotoxicity risk than that of (-)-CYF. The study provides insight into the selective toxicity mechanisms of chiral CYF and contributes to a theoretical basis for risk assessment of low-risk pesticides.

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

Dissipation, Metabolism, Accumulation, Processing and Risk Assessment of Fluopyram and Trifloxystrobin in Cucumbers and Cowpeas from Cultivation to Consumption.

Fluopyram and trifloxystrobin are widely used for controlling various plant diseases in cucumbers and cowpeas. However, data on residue behaviors in plant cultivation and food processing are currently lacking. Our results showed that cowpeas had higher fluopyram and trifloxystrobin residues (16.48-247.65 µg/kg) than cucumbers (877.37-3576.15 µg/kg). Moreover, fluopyram and trifloxystrobin dissipated faster in cucumbers (half-life range, 2.60-10.66 d) than in cowpeas (10.83-22.36 d). Fluopyram and trifloxystrobin were the main compounds found in field samples, and their metabolites, fluopyram benzamide and trifloxystrobin acid, fluctuated at low residue levels (≤76.17 µg/kg). Repeated spraying resulted in the accumulation of fluopyram, trifloxystrobin, fluopyram benzamide and trifloxystrobin acid in cucumbers and cowpeas. Peeling, washing, stir-frying, boiling and pickling were able to partially or substantially remove fluopyram and trifloxystrobin residues from raw cucumbers and cowpeas (processing factor range, 0.12-0.97); on the contrary, trifloxystrobin acid residues appeared to be concentrated in pickled cucumbers and cowpeas (processing factor range, 1.35-5.41). Chronic and acute risk assessments suggest that the levels of fluopyram and trifloxystrobin in cucumbers and cowpeas were within a safe range based on the field residue data of the present study. The potential hazards of fluopyram and trifloxystrobin should be continuously assessed for their high residue concentrations and potential accumulation effects.

Systematic assessment of cyflumetofen toxicity in soil-earthworm (Eisenia fetida) microcosms.

Cyflumetofen was widely applied in agriculture with its excellent acaricidal effect. However, the impact of cyflumetofen on the soil non-target organism earthworm (Eisenia fetida) is unclear. This study aimed to elucidate the bioaccumulation of cyflumetofen in soil-earthworm systems and the ecotoxicity of earthworms. The highest concentration of cyflumetofen enriched by earthworms was found on the 7th day. Long-term exposure of earthworms to the cyflumetofen (10 mg/kg) could suppress protein content and increases Malondialdehyde content leading to severe peroxidation. Transcriptome sequencing analysis demonstrated that catalase and superoxide-dismutase activities were significantly activated while genes involved in related signaling pathways were significantly upregulated. In terms of detoxification metabolic pathways, high concentrations of cyflumetofen stimulated the number of Differentially-Expressed-Genes involved in the detoxification pathway of the metabolism of glutathione. Identification of three detoxification genes (LOC100376457, LOC114329378, and JGIBGZA-33J12) had synergistic detoxification. Additionally, cyflumetofen promoted disease-related signaling pathways leading to higher disease risk, affecting the transmembrane capacity and cell membrane composition, ultimately causing cytotoxicity. Superoxide-Dismutase in oxidative stress enzyme activity contributed more to detoxification. Carboxylesterase and glutathione-S-transferase activation play a major detoxification role in high-concentration treatment. Altogether, these results contribute to a better understanding of toxicity and defense mechanisms involved in long-term cyflumetofen exposure in earthworms.

Photodegradation of the Novel Herbicide Pyraquinate in Aqueous Solution: Kinetics, Photoproducts, Mechanisms, and Toxicity Assessment.

Pyraquinate, a newly developed 4-hydroxyphenylpyruvate dioxygenase class herbicide, has shown excellent control of resistant weeds in paddy fields. However, its environmental degradation products and corresponding ecotoxicological risks after field application remain ambiguous. In this study, we systematically investigate the photolytic behaviors of pyraquinate in aqueous solutions and in response to xenon lamp irradiation. The degradation follows first-order kinetics, and its rate depends on pH and the amount of organic matter. No vulnerability to light radiation is indicated. Ultrahigh-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry and UNIFI software analysis reveals six photoproducts generated by methyl oxidation, demethylation, oxidative dechlorination, and ester hydrolysis. Gaussian calculation suggests that activities due to hydroxyl radicals or aquatic oxygen atoms caused these reactions on the premise of obeying thermodynamic criteria. Practical toxicity test results show that the toxicity of pyraquinate to zebrafish embryos is low but increases when the compound is combined with its photoproducts.

Computer-aided toxicity prediction and potential risk assessment of two novel neonicotinoids, paichongding and cycloxaprid, to hydrobionts.

Paichongding (IPP) and cycloxaprid (CYC) have been effectively used as the alternative products of imidacloprid (IMI) against IMI-resistant insects and exhibit a great market potential. However, risk assessment of IPP and CYC for non-target organisms, especially ecological risk assessment for non-target aquatic organisms, is still lacking. Here, we predicted the toxicity and potential risks of IPP, CYC, and their transformation products (TPs) to hydrobionts. The results indicated that IPP and CYC could generate 428 and 113 TPs, respectively, via aerobic microbial transformation. Nearly half of the IPP TPs and nearly 41 % of the CYC TPs exhibited high or moderate toxicity to Daphnia or fish. Moreover, we found that IPP, CYC, and 80 TPs of them posed potential risks to aquatic ecosystems. Almost all harmful TPs contained a 6-chloropyridine ring structure, suggesting that this structure may be associated with the strong toxicity of these TPs to aquatic organisms, and these TPs (IPP-TP2 or CYC-TP2, IPP-TP197 or CYC-TP71, IPP-TP198 or CYC-TP72, and IPP-TP212 or CYC-TP80) may appear in aquatic environments as final products. The risks posed by these TPs to aquatic ecosystems require more attention. This study provides insights into the toxicity and ecological risks of IPP and CYC.

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.

Hydrolysis, Photolysis, and Biotoxicity Assessment of a Novel Biopesticide, Guvermectin.

Guvermectin is a biopesticide isolated from the secondary metabolites of Streptomyces sp. NEAU6, an endogenous actinomyces of a Chinese medicine named Paris polyphylla. However, the environmental degradation behavior and biotoxicity of guvermectin are still unclear, which may affect its rational application. Therefore, the degradation of guvermectin in water at different pH values (pH 4, pH 6, pH 7, and pH 9) and with or without light was investigated in the laboratory. The results showed that guvermectin could be degraded in pH 4 solution, and the presence of light irradiation enhanced the degradation process with a DT50 of 2.95 and 12 days for photolysis and hydrolysis, respectively. However, guvermectin was fairly stable in other conditions. Three products transformed from guvermectin degradation were identified by UPLC-QTOF/MS. Biotoxicity assessment was performed on Danio rerio and Daphnia magna Straus by ECOSAR prediction and in vivo biological tests. The test data showed that guvermectin and its transformation products exhibited low toxicities to D. rerio and D. magna Straus (LC50/EC50 > 100 mg a.i./L), and the transformation products had lower toxicity than their parent substance. The results provided a reference for elucidating the potential risk of guvermectin to nontarget organisms and promoting its rational use.

Photodegradation of enestroburin in water by simulated sunlight irradiation: Kinetics, isomerization, transformation products identification and toxicity assessment.

Enestroburin is the first strobilurin fungicide developed by China and has been widely used to control fungal disease for 15 years. Investigation of its photolytic behaviour is essential for the comprehensive evaluation of its ecological risk. The effects of solution pH, humic acid (HA) and Fe(III) ions on photolysis were studied. The direct photolysis rates of enestroburin in the acidic solution (pH = 4) was faster than that in the basic (pH = 7) or neutral condition (pH = 9). HA and Fe3+ ions inhibited photolysis by the light screening effect. The photolysis of enestroburin was very fast due to the generation of photo-isomers. Seven isomeric products of enestroburin were observed using SFC-MS/MS, and the reaction mechanism for photo-induced isomers was proposed. The reaction occurred on three double bonds, including tautomerism of enol ether and oxonium and the triplet energy transfer of the CC and CN double bond. 12 transformation products (TPs) were identified by screening suspect compounds and non-target compounds, and one product (M-381) was synthesized for confirmation and quantification. A probable transformation mechanism was suggested based on the identified TPs and DFT calculations. The main transformation reactions included hydration, hydrolysis, oxidation, reduction and decarboxylation. Finally, the toxicities of the identified TPs and parent compound to aquatic organisms were predicted using ECOSAR software, and the toxicities of enestroburin and M-381 to daphnia magna were tested in the laboratory. The toxicity classification proposed by ECOSAR is reliable to a certain extent. Enestroburin and 2 TPs (M-313 and M-327) were classified as "very toxic", which may pose a potential threat to aquatic ecosystems.

Ecological risk assessment for difenoconazole in aquatic ecosystems using a web-based interspecies correlation estimation (ICE)-species sensitivity distribution (SSD) model.

Difenoconazole is a typical triazole fungicide that can inhibit demethylation during ergosterol synthesis. Due to its wide use, difenoconazole is frequently detected in surface water, paddy water, agricultural water, and other aquatic environments. Presently, an assessment of the ecological risk posed by difenoconazole in aquatic ecosystems is lacking. Here, a web-based interspecies correlation estimation (ICE)-species sensitivity distribution (SSD) model was first applied to assess the ecological risk of difenoconazole in aquatic environments. Meanwhile, maximum acceptable concentration (MAC), maximum risk-free concentration (MRFC), and risk quotient (RQ) values were used to evaluate the potential risk of difenoconazole to aquatic organisms. Our results showed that an aquatic MAC value of 0.31 µg/L was acceptable for difenoconazole in aquatic environments. Further, the detected concentration of difenoconazole was lower than the MRFC value of 0.09 µg/L indicating no risk to aquatic organisms. Assessment data suggested that difenoconazole exhibited potential risks to eight studied aquatic ecosystems (including surface water, paddy water, and agricultural water) in different countries (RQ > 1), indicating that difenoconazole overuse could cause adverse effects to aquatic organisms in these aquatic ecosystems. Thus, restricted use and rational use of difenoconazole are recommended.

Degradation of difenoconazole in water and soil: Kinetics, degradation pathways, transformation products identification and ecotoxicity assessment.

Difenoconazole is a widely used triazole fungicide that has been frequently detected in the environment, but comprehensive study about its environmental fate and toxicity of potential transformation products (TPs) is still lacking. Here, laboratory experiments were conducted to investigate the degradation kinetics, pathways, and toxicity of transformation products of difenoconazole. 12, 4 and 4 TPs generated by photolysis, hydrolysis and soil degradation were identified via UHPLC-QTOF/MS and the UNIFI software. Four intermediates TP295, TP295A, TP354A and TP387A reported for the first time were confirmed by purchase or synthesis of their standards, and they were further quantified using UHPLC-MS/MS in all tested samples. The main transformation reactions observed for difenoconazole were oxidation, dechlorination and hydroxylation in the environment. ECOSAR prediction and laboratory tests showed that the acute toxicities of four novel TPs on Brachydanio rerio, Daphnia magna and Selenastrum capricornutum are substantially lower than that of difenoconazole, while all the TPs except for TP277C were predicted chronically very toxic to fish, which may pose a potential threat to aquatic ecosystems. The results are important for elucidating the environmental fate of difenoconazole and assessing the environmental risks, and further provide guidance for scientific and reasonable use.

Cumulative risk assessment of dietary exposure to triazole fungicides from 13 daily-consumed foods in China.

The agroeconomic benefits of the routine use of triazole fungicides on crops have been evident for more than 40 years. However, increasing evidence shows that residues of triazoles are ubiquitous in various foods and thus could pose a potential health risk to humans. We analyzed 3406 samples of 13 food commodities that were collected from markets in 9 regions across China, and assessed the health risk of both chronic and acute exposure to the triazoles for Chinese children (1-6 years old) and the general population. Among all samples, 55.52% had triazoles in concentrations of 0.10-803.30 µg/kg, and 29.77% of samples contained a combination of 2-7 triazoles. Tebuconazole and difenoconazole were the most commonly found triazoles in the foods, being detected in 33.44% and 30.45% of samples, respectively. Chronic and acute cumulative risk assessment for total triazoles based on a relative potency factor method revealed that exposure to triazoles from these particular commodities was below the levels that might pose a health risk (chronic hazard index range, 5.90×10-7 to 1.83×10-3; acute hazard index range, 7.77×10-5 to 0.39, below 1). Notably, dietary exposure risk for children was greater than that for the general population-particularly for the acute intake of mandarin, grape, and cucumber (acute hazard index values of 0.35-0.39). Despite the low health risk, the potential hazards of exposure to triazoles should raise public concern owing to their ubiquitous presence in common foods and potential cumulative effects.

Carboxin and its major metabolites residues in peanuts: Levels, dietary intake and chronic intake risk assessment.

We developed an ultra-performance liquid chromatography-tandem mass spectral method to determine the fungicide carboxin and its metabolites, oxycarboxin and carboxin sulfoxide in peanut samples. The method was used to detect the concentration of the analytes in the samples from fields and markets. The total residue quantities in peanut kernels were used to evaluate the chronic dietary risk of total carboxin upon peanut consumption. The estimated dietary intake of carboxin from peanuts whose seeds had been treated with carboxin at the recommended dose was between 0.020% and 0.344% of acceptable daily intake and the risk was found to be negligible. The chronic dietary risk assessment from markets and commercial field samples for various groups of humans indicated that the group with the greatest degree of exposure was 45 to 75-year-old women who lived in rural areas. However, their acceptable daily intake percentage was 0.006%, meaning that their health risk was extremely small.

Human health safety studies of a new insecticide: Dissipation kinetics and dietary risk assessment of afidopyropen and one of its metabolites in cucumber and nectarine.

To preliminarily study the law of natural dissipation and the relation to human health of a new insecticide (afidopyropen), the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method and a UHPLC-MS/MS system were used to extract and detect the afidopyropen and its metabolite (M440I007) from cucumber and nectarine. The limits of quantitation (LOQs) of both target compounds in two matrixes were reduced to 0.0001 mg/kg. Dissipative dynamics experiments indicated that afidopyropen residue dissipation is more consistent with a two-compartment kinetic model than a first-order kinetic model whether in cucumber or nectarine. The half-lives were less than 1.1 and 2.0 days in the distribution phase and up to 9.9 and 27.7 days in the elimination phase in cucumber and nectarine, respectively. The correlation coefficients were 0.9620, 0.9391, and 0.9923 for cucumber and 0.9676 and 0.9985 for nectarine from different locations. M440I007 initially increased rapidly, reached a maximum at 2 days, and then decreased gradually over time. Finally, dietary risk assessment indicated that the mixed residues of afidopyropen and M440I007 at the recommended dosage would not cause health concerns in population.

Bioavailability assessment of thiacloprid in soil as affected by biochar.

Biochars can significantly sorb pesticides, and reduce their bioavailability in agricultural soils. In this study, the effects of a type of biochar (BC500) on the sorption, degradation, bioaccumulation and bioavailability of thiacloprid, which is a commonly used insecticide, were investigated. The thiacloprid sorption constant (Kf values) increased by 14 times after 2% BC500 application, and the degradation of the insecticide decreased with increasing amounts of the biochars in the soil. Coupled with the exhaustive extraction and single-point Tenax method, the bioavailability of thiacloprid was predicted in the presence of the biochar. In soils amended with BC500, the thiacloprid concentrations accumulated in Tenax correlated well with those observed in earthworms (R2 = 0.887), whereas the concentrations extracted by exhaustive method followed a less significant relationship with those in earthworms (R2 = 0.624). The results of Tenax extractions and earthworm bioassays indicate that biochar reduces the bioavailability of thiacloprid in soil, but the delayed degradation and increased earthworm accumulation in aged biochar-amended soil imply that the environmental risks of biochar application to earthworms remain.

Simultaneous determination of oxathiapiprolin and two metabolites in fruits, vegetables and cereal using a modified quick, easy, cheap, effective, rugged, and safe method and liquid chromatography coupled to tandem mass spectrometry.

An effective and rapid analytical method for the simultaneous determination of a new fungicide oxathiapiprolin and its metabolites (IN-E8S72 and IN-WR791) residues in fruits (grape, watermelon, watermelon peel), vegetables (cucumber, tomato, potato) and cereal (wheat) was developed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) using the modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction concept. Three target compounds were extracted from all matrices with 1% (V/V) formic acid aqueous solution and acetonitrile then cleaned by dispersive solid phase extraction (dSPE) with octadecylsilane (C18) and graphitized carbon black (GCB). The determination of the target compounds was achieved within a 5.1min run time by using an UPLC HSS T3 column connected to an electrospray ionization source (ESI, positive ion mode) for oxathiapiprolin and the negative mode for the two metabolites. The method showed excellent linearity (R(2)>0.9904) for target compounds. The limit of detection (LOD) for the three compounds ranged from 0.5µgkg(-1) to 7.5µgkg(-1) and the limits of quantitation (LOQ) were 1µgkg(-1) and 10µgkg(-1) for oxathiapiprolin and the metabolites, respectively. The mean recoveries from seven matrices ranged from 81.5 to 110.7%, with intra-day relative standard deviations (RSDr) in the range of 0.8-12.0% for all three test compounds. The inter-day RSDR were less than 14.5% for all of the recovery tests. The method was successfully applied for simultaneous analysis of oxathiapiprolin and its metabolites in actual trial samples, indicating its effectiveness in investigating oxathiapiprolin and its metabolites in the food.