scholarly journals Simulation of Pesticide Behavior in a Paddy Block by a Pesticide Fate and Transport Model

10.5109/16138 ◽  
2009 ◽  
Vol 54 (2) ◽  
pp. 505-512
Author(s):  
Thai Khanh Phong ◽  
Kazuaki Hiramatsu ◽  
Son Hong Vu ◽  
Satoru Ishihara ◽  
Hirozumi Watanabe
Keyword(s):  
Transport Model ◽  
Fate And Transport

scholarly journals Generalizing Source Geometry of Site Contamination by Simulating and Analyzing Analytical Solution of Three-Dimensional Solute Transport Model

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Xingwei Wang ◽  
Jiajun Chen ◽  
Hao Wang ◽  
Jianfei Liu
Keyword(s):  
Solute Transport ◽  
Contaminant Transport ◽  
Transport Model ◽  
Three Dimensional ◽  
Fate And Transport ◽  
Source Area ◽  
Equation Model ◽  
Plume Migration ◽  
Advective Diffusion ◽  
Source Geometry

Due to the uneven distribution of pollutions and blur edge of pollutant area, there will exist uncertainty of source term shape in advective-diffusion equation model of contaminant transport. How to generalize those irregular source terms and deal with those uncertainties is very critical but rarely studied in previous research. In this study, the fate and transport of contaminant from rectangular and elliptic source geometry were simulated based on a three-dimensional analytical solute transport model, and the source geometry generalization guideline was developed by comparing the migration of contaminant. The result indicated that the variation of source area size had no effect on pollution plume migration when the plume migrated as far as five times of source side length. The migration of pollution plume became slower with the increase of aquifer thickness. The contaminant concentration was decreasing with scale factor rising, and the differences among various scale factors became smaller with the distance to field increasing.

The use of Runoff and Surface Water Transport and Fate Models in the Pesticide Registration Process

1992 ◽  
Vol 6 (3) ◽  
pp. 743-748 ◽  
Author(s):  
Paul L. Zubkoff
Keyword(s):  
Surface Waters ◽  
Environmental Fate ◽  
Transport Model ◽  
Numerical Models ◽  
Chemical Properties ◽  
Chemical Characterization ◽  
Fate And Transport ◽  
Environmental Parameters ◽  
Field Studies ◽  
Chemical Application

In support of the registration and reregistration processes under FIFRA ‘88, numerical models are used to estimate the dissolved runoff and soil erosion loadings of pesticides to surface waters and the subsequent fate and transport of pesticides in the receiving waters. Uses for simulations include:1. Helping to determine whether additional studies on the fate and distribution of a candidate chemical in the environment and/or ecological effects may be needed when full chemical characterization is incomplete.2. Helping to more fully integrate data submissions of laboratory and field observations.3. Estimating probable fate and distribution of an agrochemical after a severe runoff event.4. Comparing alternative chemical application rates and methods for the same chemical/soil/crop/environmental combinations.5. Comparing different soil/crop/environmental combinations representing different geographical areas with the same chemical.6. Evaluating preliminary designs of proposed field studies.7. Gaining insight into the environmental fate of modern chemicals that are applied at 1 to 2% of the rates of older chemicals when sampling designs and analytical methods are not available.The Office of Pesticide Programs (OPP) commonly employs the SWRRB (45, 46) and PRZM (8, 9) models for runoff and EXAMS II (5), a fate and transport model, for surface waters. These three models are used in conjunction with appropriate databases for soils, chemical properties, and meteorological and other environmental parameters. Registrants are encouraged to clearly state assumptions, identify values for parameters by citation, report results of simulations with summary tables and graphics, and interpret their results in relation to current scientific disciplines.

scholarly journals Inverse modelling for mercury over Europe

2006 ◽  
Vol 6 (1) ◽  
pp. 795-838 ◽  
Author(s):  
Y. Roustan ◽  
M. Bocquet
Keyword(s):  
Boundary Conditions ◽  
Emission Inventory ◽  
Transport Model ◽  
Fate And Transport ◽  
Elemental Mercury ◽  
Regional Model ◽  
Inverse Modelling ◽  
Gaseous Elemental Mercury ◽  
Gaseous Mercury ◽  
Mercury Monitoring

Abstract. The fate and transport of mercury over Europe is studied using a regional Eulerian transport model. Because gaseous elemental mercury is a long-lived species in the atmosphere, boundary conditions must be properly taken into account. Ground measurements of gaseous mercury are very sensitive to the uncertainties attached to those forcing conditions. Inverse modelling can help to constrain the forcing fields and help to improve the predicted mercury concentrations. More generally, it allows to reduce the weaknesses of a regional model against a global or hemispherical model for such diffuse trace constituent. Adjoint techniques are employed to relate rigorously and explicitly the measurements to the forcing fields. This way, the inverse problem is clearly defined. Using EMEP measurements of gaseous mercury and performing the inversions, it is shown that boundary conditions can be improved significantly as well as the forecast concentrations. Using inverse modelling to improve the emission inventory is however much more difficult since there are currently not enough mercury monitoring stations, and their location far from Europe centre.

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