Transport of Three Herbicides in Ground Water at Twin Lake Test Site, Chalk River, Ontario, Canada
| Autor: | Piotr Maloszewski, Andrzej Zuber, G Matthess, E Bedbur |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Thermodynamics
Aquifer Kinetic energy Soil chemistry.chemical_compound TRACER Water Movements Computers in Earth Sciences Exponential decay Water Science and Technology Ontario Hydrology geography Aniline Compounds geography.geographical_feature_category Herbicides Triazines Chemistry Phenylurea Compounds Models Theoretical Flow velocity Chlortoluron Tritium Chemical equilibrium Water Pollutants Chemical Environmental Monitoring |
| Zdroj: | Ground Water. 41:376-386 |
| ISSN: | 0017-467X |
| DOI: | 10.1111/j.1745-6584.2003.tb02607.x |
| Popis: | A field tracer test performed under natural flow conditions at the Twin Lake test site, Chalk River Laboratories of the Atomic Energy of Canada Ltd. in Chalk River, Ontario, Canada, using tritium and three herbicides (Chlor-toluron, Terbuthylazine, and Pendimethalin) was interpreted using the dispersion equation with a combined reaction model. The reaction model couples an instantaneous equilibrium reaction governed by a linear adsorption isotherm with a reversible or irreversible kinetic reaction of the first order, and decay. An improved interpretation method consists of a simultaneous fitting of theoretical concentration and mass-recovery curves to the experimental data, which leads to a more reliable determining of reaction models and improves the accuracy of fitting. Tritium served as the reference tracer to determine the flow velocity, dispersivity, and the recovery of the herbicides. Chlortoluron was slightly delayed by equilibrium exchange with strongly reduced concentration due to an irreversible kinetic reaction and/or decay. Terbuthilazine was slightly delayed by equilibrium exchange, with strongly reduced concentration due to a reversible kinetic reaction with some influence of decay. A strong equilibrium reaction and a strong reversible kinetic reaction without degradation governed the transport of Pendimethalin, reducing considerably its concentration. The results obtained show that simulations based only on Kd and decay constant, especially if these parameters are found in the laboratory, may considerably differ from those performed with reaction parameters determined in properly performed field tests. The dominant reaction types, and the values of parameters found in the study, supply useful information on the transport of the investigated herbicides in sandy aquifers under natural flow conditions. |
| Databáze: | OpenAIRE |
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