Protection of the groundwater against loads of plant protection products: validation of the new EU-simulation model FOCUS PELMO 4 for a reliable prediction of the leaching potential of PPP into groundwater - Part A

The tiered approach for groundwater risk assessment of plant protection products in Europe (FOCUS) is evaluated to ensure whether this approach also represents and covers German environmental conditions. A comparison between modelled leachate concentrations and actual measurements from outdoor lysimeter studies provide evidence that a reliable and safe prediction of leachate concentrations for most of the 104 investigated substances is ensured when harmonized EU endpoints are used for modelling. Based on examples it is demonstrated that inverse modelling of lysimeter studies cannot be recommended as standard method for higher risk assessment due to its complexity and high uncertainty.