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In order to study the status of pesticide residues in different land use types of soil in Jiaodong area of China, surface soil samples were collected from the main producing areas of apple, peanut and corn on the basis of investigation of the pesticide application on major crops in Jiaodong area. The residues of 43 commonly used pesticides on apples, peanuts, and corn were analyzed by gas chromatography tandem mass spectrometry (GC-MS/MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The monitoring results showed that 18 pesticides were detected in soil samples, and the residues ranged from <0.005 to 0.18 mg/kg, with the detection rates of 1.4%-45.7%. The detection rate of imidacloprid, tebuconazole, carbendazim, DDTs, acetochlor and difenoconazole were relatively high. There were significant differences in the types and contents of pesticides in different land use types of soil. In soil samples from apple orchard, 16 pesticides were detected and the detection rates of 6 pesticides were relatively high, including tebuconazole, imidacloprid, difenoconazole, carbendazim, chlorpyrifos and DDTs. In soil samples of peanut field, 8 pesticides were detected and the detection rates of five pesticides were relatively high, including acetochlor, imidacloprid, DDTs, carbendazim and atrazine. In soil samples of corn field, 11 pesticides were detected and the detection rates of five pesticides were relatively high, including imidacloprid, acetochlor, DDTs, carbendazim and difenoconazole. The content of DDTs in one soil sample of corn field (0.18 mg/kg) was higher than the risk screening value, indicating a possible risk of soil pollution in agricultural land. It inferred that the soil environmental monitoring and collaborative monitoring of agricultural products should be strengthened. This study provides basic data for the pesticide pollution situation of different land use types of soil, and also provides reference for the pest control and ecological risk assessment. In the future, it is necessary to continuously enhance the regulatory and monitoring systems, and continuously improve the awareness of pesticide use standards and the environmental quality of soil. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Natural Disasters is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Chinese Journal of Computational Mechanics / Jisuan Lixue Xuebao is the property of Chinese Journal of Computational Mechanics Editorial Office, Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Advanced Textile Technology is the property of Zhejiang Sci-Tech University Magazines and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Control Theory & Applications / Kongzhi Lilun Yu Yinyong is the property of Editorial Department of Control Theory & Applications and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the residual characteristic and safety of hexaconazole in kiwifruit, an analytical method was developed for the determination of hexaconazole residue in kiwifruit. The dissipation dynamics and final residues of hexaconazole in kiwifruit were investigated by this method. A simple and efficient pretreatment method called QuEChERS was used. Samples were extracted with acetonitrile and analyzed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). And the external standard and peak area method were employed for the quantitative analysis. Residual dissipation dynamics and final residue levels of hexaconazole in kiwifruit from six experimental sites (Yantai in Shandong Province, Yuncheng in Shanxi Province, Xianyang in Shaanxi Province, Wuhan in Hubei Province, Suzhou in Anhui Province and Jiulongpo in Chongqing) were determined. The results showed that the dissipation of hexaconazole in kiwifruit was rapid, with halflives of 13.9-17.8 d. The residual contents of hexaconazole in kiwifruit decreased according to the firstorder kinetics equation. The chronic dietary intake risk assessment results indicated that the national estimated daily intake (NEDI) of hexaconazole in all kinds of food was 1.690 2 μg/(kg bw·d), and the risk quotient (RQ) was 0.338, which demonstrated that hexaconazole applied to kiwifruit had low risk. If kiwifruit was sprayed 3 times with 75 mg a.i./kg of 30% hexaconazole SC, 21 days after the last spraying, the residue of hexaconazole in kiwifruit had low risk for dietary. Therefore, the recommended safe interval of 30% hexaconazole SC in kiwifruit was recommended to be 21 days. [ABSTRACT FROM AUTHOR]

To evaluate the safety of thiophanate-methyl in kiwi fruit, the QuEChERS-ultra high performance liquid chromatography-tandem mass spectrometry (QuEChERS-UPLC-MS/MS) analysis method was used to analyze the residues of thiophanate-methyl and its metabolite carbendazim in kiwi fruit. The kinetic equation and half-life of thiophanate-methyl residues in kiwi fruit were calculated. The dietary intake risk assessment was conducted. The maximum residue limit (MRL) of thiophanatemethyl in kiwi fruit was recommended and the safety of its metabolite carbendazim was evaluated. The results showed that the recovery rates of thiophanate-methyl and carbendazim were 85%-102% and 86%-101%, respectively, and their relative standard deviations (RSD) were 1.0%-7.1% and 2.1%-5.2%, respectively, at the spiked levels of 0.01, 0.1 and 1.0 mg/kg. The limits of quantitation (LOQ) of two pesticides on kiwi fruit were both 0.01 mg/kg. The regulation of thiophanate-methyl residues in kiwi fruit conformed to the first-order reaction kinetic equation, with the half-life of 10.1-10.5 d. When the recommended dosage and 1.5 times of the recommended dosage (875 mg/kg, 1 166.7 mg/kg) of thiophanate-methyl (70% WP) were sprayed for 3-4 times and the harvest interval was 21 days, the dietary risk quotient (RQ) was calculated as 78.7%. The result was acceptable to the general population and a MRL valaue of 5 mg/kg was recommended. The metabolite carbendazim had a greater risk of exceeding the standard of 0.5 mg/kg according to GB 2763. The MRL valaue of thiophanate-methyl should be established in kiwi fruit, while the MRL value of carbendazim should be reevaluated. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A method was developed for the quantitative determination of spirotetramat, diafenthiuron and their metabolite residues (spirotetramat-enol, spirotetramat-enol-glucoside, spirotetramat-monohydroxy, spriotetramat-keto-hydroxy, diafenthiuron-urea, diafenthiuron-amide) by QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were homogenized, extracted with V (acetonitrile) : V(formic acid)=10 : 1, and cleaned-up by custom QuEChERS tubes. The separation was performed on a Shimadu Shim-pack XR-ODS column(75 mm × 2.0 mm, 1.6 μm). The compounds were identified by MS/MS in positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) mode, and quantified by external standard method. The linearities of diafenthiuron-urea and diafenthiuron-amide ranged from 0.001 to 0.1 mg/L. And that of the other six compounds ranged from 0.005 to 0.5 mg/L, with the correlation coeffecients higher than 0.999 3. At the fortified level from 0.001 mg/kg to 0.5 mg/kg in pear, grape, watermelon, kale, celery and leek, the average recoveries of all the eight compounds ranged from 68% to 94% with the relative standard deviations varied from 5.4% to 15%. The limits of quantification (LOQ) of the analytes were 0.001-0.005 mg/kg. The method is simple, rapid, accurate and suitable for the confirmation and quantification of those eight compounds in fruits and vegetables. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)