PARENT SESSION
PM22 - Coping with Uncertainty in Fate/Exposure Models
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P407) A model based tool for higher tier risk assessment of pesticides at catchment scale.
Petersen, Søren*,1, Styczen, Merete1, Sørensen, Peter B.2, Christensen, Michael1, Jessen, Oluf Z.1, Rasmussen, Dorte1, Andersen, Mikkel B.1, 1 DHI - Water and Environment, 2970 Hørsholm, Denmark, Denmark2 NERI - National Environmetal Research Institute, 4000 Roskilde, Denmark, Denmark
ABSTRACT- For higher tier risk assessment of pesticides a model based tool for prediction of the fate and transport of pesticides in surface water of small first order streams are about to be adapted by the Danish EPA. The tool is based on existing established professional models of hydraulic (HD), advection and dispersion (AD) which have been coupled to chemical fate models. The process formulations of the chemical fate model include several innovative aspects, such as kinetic sorption and particle-facilitated transport through macropores in the soil and the underlying existing HD and AD model have been acknowledged by independent comparisons of professional model systems. It is therefore appropriate to consider the tool as state of the art. For two small danish first order streams in agricultural catchment the model system was set up, calibrated and validated against measured concentrations of pesticides. Results of the calibration and validations are provided. The model is supposed to be parameterized by the data currently available for the EPA in connection with approvals of pesticides. These data might be quite variable and an uncertainty analysis of the model was therefore conducted. On the basis of the uncertainty analysis recommendations for optimization of the data requirements is provided.
Key words: Pesticides, Fate and transport models, Uncertainty analysis, Calibration and validation