EUROPE: New PELMO and PEARL Versions Released

New versions of the models PELMO (i.e. v.6.6.4) and PEARL (i.e. v.5.5.5) used for Predicted Environmental Concentrations in Groundwater (PECgw) calculations, accompanied by a new version of the Generic Guidance for Tier 1 FOCUS GroundWater Assessments (i.e. v.2.3) were released by the FOrum for Co-ordination of pesticide fate models and their USe (FOCUS DG SANTE).

The FOCUS DG SANTE recommends that the previous versions of the generic guidance (v.2.2), of PELMO (v.5.5.3) and of PEARL (v.4.4.4) should no longer be used in submissions made after 1 January 2022.

Updates of version 2.3 of the generic guidance are:

  • Update of the equations for converting pH measured in CaCl2 and KCl to pH measured in H2O, and,
  • Irrigation water in PELMO and PEARL is now applied at the soil surface for the crops apples, citrus and vines,

both to reflect the EFSA guidance on PECsoil calculation (EFSA Journal 2017;15(10):4982);

  • Update on guidance on pesticide property parameter derivation in case of pH dependence, to reflect the EFSA report on the ‘repair action’ on the FOCUS surface water scenarios (EFSA Journal 2020;18(5):6119);
  • Reference to the OECD 106 evaluators checklist in relation to equilibrium sorption parameters added (EFSA supporting publication 2017:EN-1326);
  • New options for defining transformation product formation fractions in PELMO;
  • Correction to periods to crop factors (Kc) for the crop onions at the Porto and Thiva scenarios;
  • Reference added to the new endorsed guidance determining aged (non equilibrium) sorption parameters (SANTE/12586/2020-REV 0).

The new versions of PELMO and PEARL were also developed to work in combination with the new PERSAM tool for PECsoil calculations. They will be used to generate higher tier (‘Tier 3A’) PECsoil (reference to our previous post on PERSAM).


To download: 

Generic Guidance for Tier 1 FOCUS GroundWater Assessments (version 2.3) (June 2021)

FOCUS PELMO 6.6.4 (GW) 6.6.1 (soil)



See also our previous articles: 

EUROPE – EFSA: New version of PERSAM tool for PECsoil calculations

EUROPE – EFSA: Revision of Surface Water FOCUS Scenarios

EUROPE: Guidance on Aged Sorption Studies Adopted


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