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To evaluate the residue behavior and risk of pyraclostrobin and tebuconazole in peppers, an analytical method for the determination of these two fungicides in peppers was developed using Ultra-high Performance Liquid Chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). Pepper samples were extracted with acetonitrile, and cleaned up with primary secondary amine (PSA) and graphitized carbon black (GCB). The average recoveries for three fortification levels of pyraclostrobin and tebuconazole in peppers were 86.7-101.4% and 81.7-104.4% with relative standard deviations (RSDs) of 4.0-7.2% and 3.8–10.9%, respectively. The limit of quantifications (LOQs) for the two fungicides in peppers were 0.01 mg/kg. Terminal residue trial of 30% pyraclostrobin and tebuconazole suspension concentrate (SC) on peppers was investigated under open fields and greenhouses conditions. The results showed that the terminal residues of pyraclostrobin and tebuconazole in peppers were lower than the maximum residue limits (MRLs) of peppers established by GB 2763 − 2021 (0.5 mg/kg for pyraclostrobin and 2 mg/kg for tebuconazole). A statistical t-test was used to study the significant difference between open fields and greenhouses, and the results indicated that there is no significant difference between different planting conditions of greenhouses and open fields. Using international estimate of short-term intake (IESTI) calculation model of Joint FAO/WHO Meeting on Pesticide Residues (JMPR), the acute dietary exposure risk of two fungicides in peppers was acceptable for general population with the IESTIs varied from 0–3% of ARfD for pyraclostrobin and 0–5% for tebuconazole.

The fungal species Fusarium can cause devastating disease in agricultural crops. Phenamacril is an extremely specific cyanoacrylate fungicide and a strobilurine analog that has excellent efficacy against Fusarium. To date, information on the mechanisms involved in the uptake, accumulation, and metabolism of phenamacril in plants is scarce. In this study, lettuce and radish were chosen as model plants for a comparative analysis of the absorption, accumulation, and metabolic characteristics of phenamacril from a polluted environment. We determined the total amount of phenamacril in the plant-water system by measuring the concentrations in the solution and plant tissues at frequent intervals over the exposure period. Phenamacril was readily taken up by the plant roots with average root concentration factor ranges of 60.8-172.7 and 16.4-26.9 mL/g for lettuce and radish, respectively. However, it showed limited root-to-shoot translocation. The lettuce roots had a 2.8-12.4-fold higher phenamacril content than the shoots; whereas the radish plants demonstrated the opposite, with the shoots having 1.5 to 10.0 times more phenamacril than the roots. By the end of the exposure period, the mass losses from the plant-water systems reached 72.0% and 66.3% for phenamacril in lettuce and radish, respectively, suggesting evidence of phenamacril biotransformation. Further analysis confirmed that phenamacril was metabolized via hydroxylation, hydrolysis of esters, demethylation, and desaturation reactions, and formed multiple transformation products. This study furthers our understanding of the fate of phenamacril when it passes from the environment to plants and provides an important reference for its scientific use and risk assessment.

Imidacloprid (IMI) as a first-generation commercial neonicotinoid has been frequently detected in the environment in recent years. In this study, the efficient degradation of IMI in soil by a thermally activated persulfate (PS) process was investigated. The degradation efficiencies of IMI were in the range of 82-97% with the PS dosage of 10 mM, when the initial concentrations of IMI were 5-50 mg/kg in the soil. Degradation of the IMI was fitted with a pseudo-first-order kinetic model under different reaction temperatures. Inhibition effects of the common inorganic anions on the IMI degradation in the system followed the order Cl

The dissipation and residue levels of thiamethoxam and its metabolite clothianidin in cowpea were investigated under field conditions. Samples of cowpea were analyzed using a QuEChERS technique with ultra-performance liquid chromatography tandem mass spectrometry. The recoveries were 86.5-118.9% for thiamethoxam and 75.6-104.1% for clothianidin, with the coefficient of variation of < 13%. The water dispersible granule formulation of thiamethoxam was applied on cowpea at 30 and 45 g active ingredient ha-1 in accordance with good agricultural practice. The half-life of thiamethoxam in cowpea was 0.8-1.6 days. The cowpea samples were gathered at 3, 7, and 10 days after the last application, and the residues of thiamethoxam in cowpea were < 0.005-0.054 mg kg-1, while those of clothianidin were < 0.005-0.008 mg kg-1. The final residues of thiamethoxam and clothianidin were below the European Union (EU) maximum residue level (0.3 mg kg-1 for thiamethoxam; 0.2 mg kg-1 for clothianidin) in cowpea after a preharvest interval (PHI) of 7 days. This study provided basic data on the use and safety of thiamethoxam and clothianidin in cowpea to help the Chinese government formulate a maximum residue level for thiamethoxam in cowpea.

A new combined difenoconazole and fluxapyroxad fungicide formulation, as an 11.7 % suspension concentrate (SC), has been introduced as part of a resistance management strategy. The dissipation of difenoconazole and fluxapyroxad applied to apples and the residues remaining in the apples were determined. The 11.7 % SC was sprayed onto apple trees and soil in Beijing, Shandong, and Anhui provinces, China, at an application rate of 118 g a.i. ha(-1), then the dissipation of difenoconazole and fluxapyroxad was monitored. The residual difenoconazole and fluxapyroxad concentrations were determined by ultrahigh-performance liquid chromatography tandem mass spectrometry. The difenoconazole half-lives in apples and soil were 6.2-9.5 and 21.0-27.7 days, respectively. The fluxapyroxad half-lives in apples and soil were 9.4-12.6 and 10.3-36.5 days, respectively. Difenoconazole and fluxapyroxad residues in apples and soil after the 11.7 % SC had been sprayed twice and three times, with 10 days between applications, at 78 and 118 g a.i. ha(-1) were measured. Representative apple and soil samples were collected after the last treatment, at preharvest intervals of 14, 21, and 28 days. The difenoconazole residue concentrations in apples and soil were 0.002-0.052 and 0.002-0.298 mg kg(-1), respectively. The fluxapyroxad residue concentrations in apples and soil were 0.002-0.093 and 0.008-1.219 mg kg(-1), respectively. The difenoconazole and fluxapyroxad residue concentrations in apples were lower than the maximum residue limits (0.5 and 0.8 mg kg(-1), respectively). An application rate of 78 g a.i. ha(-1) is therefore recommended to ensure that treated apples can be considered safe for humans to consume.

Fluazinam and dimethomorph 35% suspension concentrate (SC) is a new combined fungicide formulation introduced in China to improve fungicidal efficacy and decrease the risk of resistance in potatoes. Fluazinam and dimethomorph dissipation and residues in potatoes, potato plants, and soil under field conditions were determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Fluazinam and dimethomorph 35% SC was applied at two doses to potatoes and soil in Ningxia Autonomous Region and Anhui Province, China. Fluazinam and dimethomorph dissipation fitted first-order kinetics, and the fluazinam half-lives in potato plants and soil were 3.3–5.4 and 9.4–9.5 days, respectively. The dimethomorph half-lives in potato plants and soil were 2.1–2.6 and 5.9–8.6 days, respectively. Fluazinam and dimethomorph 35% SC was sprayed onto potato plants three or four times at application rates of 420 and 630 g a.i. ha−1 with 7 days between applications. Potato and soil samples were collected at 3, 7, and 14 days after the last application. Potatoes and soil had fluazinam concentrations of

In order to study the dissipation rates and final residues of kresoxim-methyl in strawberry and soil, two independent filed trials were performed in Beijing China. The application rates are set at 195 g of active gradient per hectare. A simple analytical method has been developed for the determination of kresoxim-methyl in strawberry and soil. Kresoxim-methyl residues were extracted with acetonitrile from strawberry and soil samples which is determined by gas chromatography coupled with mass spectrometry detection (GC-MSD). The recoveries of kresoxim-methyl in strawberry and soil were observed from 78.9 % to 104.5 % at fortification levels of 0.01-0.5 mg/kg with relative standard deviations of 4.3 %-7.3 %. The reported limits of detection were 0.05 and 0.01 mg/kg for strawberry and soil, respectively. The results showed that kresoxim-methyl dissipation in strawberry could be described as first-order equation with the half-life time of 6.24 and 6.91 days. 14 days later, the dissipation rate is 84.9 % and 83.3 %, respectively. The final residues of kresoxim-methly in the strawberry were in the range of 2.7-4.8 mg/kg at pre-harvest intervals of 1, 3, 5, 7 days which is below the Japan maximum residue limits (MRLs) standards (5 mg/kg in strawberry).

SYP-1924 is a new kind of herbicide developed by Shenyang Scicncreat Chemicals. This study has been carried out to investigate the environmental fate of SYP-1924 in rice-field system. An analytical method utilizing high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection was described for the determination of new kind of herbicide SYP-1924 in rice, rice straw, soil and water. The dissipation of SYP-1924 in soil, water and rice straw was determined using the proposed method. The results showed that dissipation of SYP-1924 in rice straw and water were found to be very faster with half-life time shorter than 1.5 days. The half-life value of SYP-1924 was observed to be 4.5 days in soil. The ultimate residues of SYP-1924 in rice were found to be below the limits of the detection at level of recommended and 1.5 times recommended dosage with an interval date of 70 days.

A specific, sensitive method was developed for the analysis of chlormequat in wheat and soil by high performance chromatography/mass spectrometry. The fortified recoveries of soil were from 75.08% to 96.55%, with RSD 3.34%–15.18%, the limit of detection of the analytical method was 0.05 ng at a signal-to-noise ratio of 3, and the limit of quantification was 0.05, 0.1, 0.5 mg/kg for soil, wheat plants and wheat grain, respectively. The degradation dynamics and final residues of chlormequat in Beijing and Changchun were investigated. The half-life of chlormequat in wheat plants were 3.15 days in Beijing and 4.56 days in Changchun, while the half-life in soil was 3.88 days in Beijing and 4.51 days in Changchun. The final residues of chlormequat in soil were not detectable, and the final residues of chlormequat in wheat grain were below 0.50 mg/kg except for 3.51 mg/kg from high dosage plot of Changchun. The fact that all the final residues were below 5 mg/kg (GB2763 in National standards of the People’s Republic of China, maximum residue limits for pesticide in food, Beijing, 2005) suggested that chlormequat could be safely used in wheat crops with the suitable dosage and application.

The purpose of this article was to establish a simple residue analysis method for S-metolachlor in maize and to study its dissipation and residue in maize field eco-system. The results showed that S-metolachlor declined rapidly in maize seedling and soil after application. The half-lives of S-metolachlor in maize seedlings in Beijing and Changchun were 6.68 and 4.85 days, respectively, and in soil were 12.81 and 14.81 days, respectively. The terminal residues of S-metolachlor in soil samples were very low (around 0.005–0.045 mg/kg), and the residues in maize seeds were not detectable. The use of S-metolachlor according to the recommended dosages in maize could be considered safe.