The GeoPEARL model

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 ug/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. A detailed description of the concepts of GeoPEARL is given in RIVM report 716601007, a user-manual is provided in RIVM report 716601008.
Details Download GeoPEARL 3.3.3

GeoPEARL runs for unique combinations of basic model inputs

GeoPEARL runs for 6405 unique combinations of basic model inputs (soil type, climate district, land-use type, groundwater depth class etc). Grid cells that share the same unique combination of parameters are referred to as 'plots'. During the creation of the spatial schematisation, results from a regional-scale hydrological model were used. In this way, it is possible to quantify fluxes and residence times of chemicals in the saturated zone. Also, it is possible to quantify the fluxes into local surface waters. The schematisation for GeoPEARL has been derived by the 'Consensus working group hydrology', which was financed by the STONE project. Details on STONE are found in Wolf et al., 2003.
Details View an introductory demo (powerpoint)

top

Particlar attention for the relationship between pesticide properties and soil properties

Details In GeoPEARL, it is possible to introduce the relationship between basic soil properties (clay content, organic matter content and sesqui-oxide content) and substance properties (sorption coefficient and degradation half-live);
Details These relationships may affect the spatial patterns of pesticide leaching to a large extend;
Details View an introductory demo (powerpoint)

top

GeoPEARL calculates the leaching for the area of potential use of a substance

Details Pesticides are usually authorised for particular crops;
Details The new decision tree therefore considers the area of potential usage, approximated by the area of crops for which a registration is requested;
Details GeoPEARL is distributed with a database of areas for 24 major cropshe leaching concentration is calculated for the area of use of substance, which is approximated by the area of the crops for which a registration is requested.
Details Considering the area of use in a leaching assessment can have a large effect on the predicted target concentration, as shown in the demo.
Details View an introductory demo (powerpoint)

top

Other model applications


GeoPearl has been developed to evaluate the Dutch policy (in particular the Long Term Crop Protection Plan, MJP-G; De Nie (Eds.), 2002). The model is a follow-up of the GeoPestras model (Tiktak et al., 1996). A European version, referred to as 'EuroPEARL' is available as well (Tiktak et al., 2004). This version could play a role in harmonised registration procedures at the European level, as proposed by the new FOCUS working group on groundwater.

EuroPEARL

The GeoPEARL User Interface

The PEARL team has developed the GeoPEARL User Interface, which gives easy access to data and model.
Details View an introductory demo (powerpoint)


Pesticidemodels.eu
top