The GeoPEARL model: Part II - User guide and update of model description

Recently, the Netherlands has adopted a new decision tree for evaluating the leaching potential of pesticides, specifically to see if the concentration in groundwater exceeds the EU drinking-water limit of 0.1 mug/L. The spatial criterion in the new decision tree states that the long-term average concentration of a pesticide or its relevant metabolites should not exceed the drinking-water limit for at least 90% of the surface area where the pesticide is potentially used. A spatially distributed model, 'GeoPEARL', has been developed to scientifically test the above criterion. GeoPEARL will play a key role in the new Dutch decision tree. The aim of this report is to provide a guideline on the use of GeoPEARL, with special emphasis on the Dutch registration procedure. This report should be used in combination with RIVM report no. 601450019, which describes the new decision tree and the role of GeoPEARL in this tree. Background information, including the theory behind the model, can be found in the earlier RIVM report, no. 716601007