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Boulange J.,Tokyo University of Agriculture and Technology | Watanabe H.,Tokyo University of Agriculture and Technology | Inao K.,Japan National Institute for Agro - Environmental Sciences | Iwafune T.,Food and Agricultural Materials Inspection Center | And 3 more authors.
Journal of Hydrology | Year: 2014

The objective of this study was to develop, verify, and validate a new GIS-based model for simulating the fate and transport of rice pesticides in river basins. A plot scale model simulating pesticide fate and transport in rice paddies (PCPF-1) was incorporated into the Soil and Water Assessment Tool (SWAT) basin scale water and pollutant transport model. The new combined model, PCPF-1@SWAT model, was first used on some base-case scenarios to verify that the PCPF-1 algorithm and the routing of variables were correctly implemented. Next, the PCPF-1@SWAT model was calibrated and validated on the Sakura River basin (Ibaraki prefecture, Japan) using mefenacet concentrations measured during the rice growing season in 2008. The modeling procedures for simulating pesticide fate and transport in a Japanese river basin were demonstrated by providing model parameters related to hydrology, land use, pesticide fate, and rice field managements methods.The water flows predicted by the PCPF-1@SWAT model in the Sakura River basin were accurate throughout the whole simulation year, with R2 and ENS statistics exceeding 0.74 and 0.71, respectively for daily flow. The use of different seepage rates had appreciable influence on the simulations. High seepage rates gave a slight overestimation of the predicted base flow during the rice growing period, whereas the base flow predictions using lower seepage rates were comparable to measured data.The PCPF-1@SWAT model successfully simulated the fate and transport of mefenacet in the Sakura River in which measured mefenacet concentrations peaked soon after the initial herbicide application in May, and decreased gradually during the months of June and July. Occasional major precipitation events caused the mefenacet concentration in streams to peak quickly due to a corresponding loss of mefenacet from paddy areas, and then rapidly decrease due to dilution by excess rainfall discharge. The simulation using a seepage rate of 0.12cmday-1 had the most accurate prediction of mefenacet concentration in river water with an R2 of 0.61 and an ENS of 0.65. © 2014 Elsevier B.V. Source


Kodama T.,Food and Agricultural Materials Inspection Center | Kurosawa Y.,Japan National Agriculture and Food Research Organization | Kitta K.,Japan National Agriculture and Food Research Organization | Naito S.,Japan National Agriculture and Food Research Organization
Journal of AOAC International | Year: 2010

The Horwitz curve estimates interlaboratory precision as a function only of concentration, and is frequently used as a method performance criterion in food analysis with chemical methods. The quantitative biochemical methods based on real-time PCR require an analogous criterion to progressively promote method validation. We analyzed the tendency of precision using a simplex real-time PCR technique in 53 collaborative studies of seven genetically modified (GM) crops. Reproducibility standard deviation (SR) and repeatability standard deviation (Sr) of the genetically modified organism (GMO) amount (%) was more or less independent of GM crops (i.e., maize, soybean, cotton, oilseed rape, potato, sugar beet, and rice) and evaluation procedure steps. Some studies evaluated whole steps consisting of DNA extraction and PCR quantitation, whereas others focused only on the PCR quantitation step by using DNA extraction solutions. Therefore, SR and Sr for GMO amount (%) are functions only of concentration similar to the Horwitz curve. We proposed SR = 0.1971C0.8685 and Sr = 0.1478C0.8424, where C is the GMO amount (%). We also proposed a method performance index in GMO quantitative methods that is analogous to the Horwitz Ratio. Source


Phong T.K.,Kyushu University | Vu S.H.,Ministry of Agriculture and Rural Development | Ishihara S.,Food and Agricultural Materials Inspection Center | Hiramatsu K.,Kyushu University | Watanabe H.,Tokyo University of Agriculture and Technology
Pest Management Science | Year: 2011

Background: Monitoring studies revealed high concentrations of pesticides in the drainage canal of paddy fields. It is important to have a way to predict these concentrations in different management scenarios as an assessment tool. A simulation model for predicting the pesticide concentration in a paddy block (PCPF-B) was evaluated and then used to assess the effect of water management practices for controlling pesticide runoff from paddy fields.Results: The PCPF-B model achieved an acceptable performance. The model was applied to a constrained probabilistic approach using the Monte Carlo technique to evaluate the best management practices for reducing runoff of pretilachlor into the canal. The probabilistic model predictions using actual data of pesticide use and hydrological data in the canal showed that the water holding period (WHP) and the excess water storage depth (EWSD) effectively reduced the loss and concentration of pretilachlor from paddy fields to the drainage canal. The WHP also reduced the timespan of pesticide exposure in the drainage canal.Conclusions: It is recommended that: (1) the WHP be applied for as long as possible, but for at least 7 days, depending on the pesticide and field conditions; (2) an EWSD greater than 2 cm be maintained to store substantial rainfall in order to prevent paddy runoff, especially during the WHP. © 2010 Society of Chemical Industry. Source


Hakoda A.,Food and Agricultural Materials Inspection Center
Nippon Shokuhin Kagaku Kogaku Kaishi | Year: 2010

Validated analytical methods have been adopted in Codex Alimentarius Commission for international regulatory analysis. They also have been needed in the Japanese Agricultural Standard (JAS) because of increased international business through the import and export. In this regard, the Food and Agricultural Materials Inspection Center (FAMIC) have designed the candidate analytical methods and conducted their interlaboratory studies in commission of the Minister of Agriculture, Forestry and Fisheries. All procedures were performed under the international harmonized protocol of method-performance study. In this article, the general procedure for analytical methods in the JAS is summarized. Practical interlaboratory studies, performed at FAMIC, are also introduced on determination of crude protein and ash in macaroni products. Source


Hiraoka H.,Food and Agricultural Materials Inspection Center | Goto T.,Shinshu University
Animal Feed Science and Technology | Year: 2010

Organic acids and some inorganic anions may have an effect on the nutritive quality of silage. To facilitate the simultaneous and quantitative measurement of nine organic acids (formate, acetate, propionate, butyrate, n-valerate, iso-valerate, n-hexanate, citrate and lactate) and three inorganic anions (nitrate, nitrite and chloride) in silage, we optimized an analysis method using capillary zone electrophoresis (CZE) with a photodiode-array detector (PDA). We then validated the optimized method in a collaborative study. Samples were extracted with water, purified through a cartridge column to remove interferences, diluted with water, filtered with a centrifugal filter and applied on the CZE. The separation was carried out with a fused-silica capillary column at 30. kV. A wavelength of 350. nm was selected for indirect UV detection and a wavelength of 275. nm was selected as a reference. A 30. mM 2,6-pyridinedicarboxylic acid (PDC) solution was used as a background electrolyte (BGE) at pH 12 with 0.5. mM of cetyltrimethylammonium hydroxide (CTAH).For the recovery study, the silage was spiked with 3.0 or 6.0g/kg of each of the nine organic acids and three inorganic anions. The mean recoveries of the acids were 0.996-1.097 and the coefficient of variation for the repeatability (CV) was within 0.071. The collaborative study included five laboratories. Grass silage was spiked with 7.0g/kg of each analyte. The mean recoveries of the acids were 0.843-1.143, the coefficients of variation for the repeatability and reproducibility (CVr and CVR) were zero to 0.058 and 0.033-0.081, respectively, and the HorRat values were 0.8-1.9. From the measurements of farm silage samples, chloride, nitrate, formate, citrate, acetate, lactate, butyrate and iso-valerate were detected, and their mean ranges were 2.7-4.4, 0-0.9, 0-2.6, 0-1.8, 0.7-5.5, 0-12.3, 0-3.4 and 0-2.4g/kg, respectively, and the coefficients of variation for the repeatability were within 0.087, 0.079, 0.083, 0.095, 0.091, 0.070, 0.103 and 0.037, respectively. Over a long-term storage period of nine months, nitrate and citrate decreased. The acetate and lactate contents were higher in the high-moisture silage than the low-moisture silage. © 2010 Elsevier B.V. Source

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