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Guidances on derivation of soil and groundwater exposure

Two major guidance documents have been noted at the EU Standing Committee on Plants, Animals, Food and Feed recently. The guidances covering the areas of derivation of soil (DegT50 values) and groundwater exposure. Both have an implementation date of 1 May 2015 and can be found on the EU website under Technical guidance - Fate and behaviour.

  1. Guidance Document for evaluating laboratory and field dissipation studies to obtain DegT50 values of active substances of plant protection products and transformation products of these active substances in soil. This Guidance Document (SANCO/12117/2014) covers a number of areas, principally relating to methods for deriving the DegT50matrix from individual laboratory and field dissipation studies and additional guidance on selecting the appropriate input parameters for use in environmental exposure modelling.
  2. Assessing Potential for Movement of Active Substances and their Metabolites to Ground Water in the EU.
    This Guidance Document (SANCO/13144/2010) describes several higher tier options for groundwater assessments.

In addition, the Generic Guidance for Tier 1 FOCUS Ground Water Assessments (version 2.2, May 2014) has been updated to reflect the EFSA DegT50 guidance (2014) and also other EFSA PPR recommendations. Principal changes include the use of two FOCUS models for PECgw (Predicted Environmental Concentration in groundwater) simulations, use of geomean values for Kom, Koc and DegT50, recommendations relating to the use of pH dependent modelling, recommended default value of 0 for the Transpiration Stream Concentration Factor (TSCF) for all compounds and new FOCUS crop interception values for some crops.