Comment on 'Regulatory FOCUS Surface Water Models Fail to Predict Insecticide Concentrations in the Field

摘要

I would like to question the suitability of the first two hypotheses for evaluating the protectiveness of the FOCUS surface water modeling approach for the EU. Hypothesis 1: "A maximum of 10% of the FOCUS step 3 PECs underestimate the measured field concentrations (MFCs)" This hypothesis is only suitable for assessing the "protectiveness" of the FOCUS sw modeling approach (which comprises a suite of 3 models and 10 generic scenarios) for the EU if all the following conditions are met: real and modeled pesticide application scenarios are similar (substance, application rate/type/season), the study areas are representative for the distribution of agro-environmental scenarios (soil, climate, crops) in the EU, and measured and modeled concentrations are indeed comparable with each other because they have the same underlying conditions (type of water body, integration period, environmental compartment, unit etc.).