Methodological approach for evaluating first tier PEC groundwater scenarios supporting the prediction of environmental concentrations of pesticides at the European scale

At present, harmonised procedures and scenarios for assessing the predicted environmental concentration (PECs) of pesticides in groundwater have been implemented through the FOCUS working groups. The effectiveness and efficiency of the risk assessment procedures will thereby strongly depend on the validity of the environmental fate model and on the validity of the selected scenarios. In contrast to the validation of environmental fate models itself, little attention has been devoted so far to the validation of scenarios.

Within this paper we present a methodological approach for validating scenarios within the framework of risk assessment. The approach was developed within the framework of the EU-FP5 research project APECOP (Effective approaches for predicting environmental concentrations of pesticides) and helps to determine the validation status of the FOCUS groundwater scenarios, as presently used in the higher tier harmonised registration of pesticides at the EU level. Validation encompasses the comparison of PECs to groundwater as obtained using the most detailed modelling approach that currently can be implemented at the Pan-European scale with the results obtained from FOCUS PECs.