PEARL is an acronym of Pesticide Emission Assessment at Regional and Local scales. PEARL is a one-dimensional, dynamic, multi-layer model, which describes the fate of a pesticide and relevant transformation products in the soil-plant system. The most important processes included in PEARL are pesticide application and deposition, convective and dispersive transport in the liquid phase, diffusion through the gas and liquid phase, equilibrium sorption, non-equilibrium sorption, first-order transformation, uptake of pesticides by plant roots, lateral discharge of pesticide with drainage water, and volatilization of pesticide at the soil surface
PEARL has been developed by three Dutch institutes (WENR, PBL and RIVM) in close co-operation.
PEARL is used to evaluate the leaching of pesticides to the groundwater, the drainage to surface waters and the persistence of pesticides in topsoils. The model supports European and Dutch pesticide registration procedures. The model is also suitable for higher tier assessments.
There are several model applications of the PEARL model. The spatially distributed model, 'GeoPEARL’ is used to evaluate the leaching of pesticides to the groundwater in the Netherlands. Metamodels of PEARL are developed and used for policy evaluation. The PEARLNEQ software package is developed to estimate long-term sorption parameters using results of experimental aged-sorption studies with soil, using a submodel for sorption and transformation that is identical to the submodel used for that purposed in the PEARL model.