In pesticide registration procedures, several stages can be distinguished. In first tier (i.e. initial) assessments, models are used to get a first indication of the leaching potential and soil exposure of a pesticide. To avoid user subjectivity during these initial assessments, target quantities and standardized scenarios have been developed.
For the leaching assessment scenarios are developed by the Forum for International Co-ordination of pesticide fate models and their Use (FOCUS). Scenario's as defined by the FOCUS modeling working group are a combination of crop, location, the long-term application schedule (i.e. annual, biennial or triennial applications) and agronomic parameters (particularly irrigation data). Scenarios have been developed for 9 locations and approximately 14 crops per location. For more information can be found on the home page of FOCUS DG SANTE (https://esdac.jrc.ec.europa.eu/projects/ground-water)
Please notice that the FOCUS website is the only place where you can get the approved model versions of PEARL and scenario's, which are used in the first tier of the EU review process according to Council Directive. (1107/2009)
EU soil exposure
EFSA has developed guidance for the exposure assessment of soil organisms to plant protection products (PPPs) and their transformation products in accordance with Regulation 1107/20091. The recommended exposure assessment procedure consists of four tiers. In higher tiers of the exposure assessment, crop interception and subsequent dissipation at the crop canopy may be included. The PEARL model can be used for the exposure assessments in the third tier. A user-friendly version of FOCUSPEARL is being developed to facilitate the tier 3B calculations of the PEC-soil for using the scenarios as specified in the guidance.