The possible entry of plant protection products into groundwater is assessed on the basis of results from simulation calculations, and experimental studies if appropriate (lysimeter studies, field leaching studies). The FOCUS-PELMO model is used for modelling the leaching behaviour of active substances contained in plant protection products and their metabolites for the authorisation procedure.

As of May 2015 the European assessment guideline „EFSA 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“; EFSA Journal 2014; 12(5);3662, (SANCO/12117/2014-final 12 December 2014) has been implemented. It is applicable to applications for approval of active substances on EU-level as well as to applications for product authorisation submitted after this date.

In the context of the authorisation procedure for plant protection products in Germany applying of the Guidance Document to its full extent is not required, if the Guidance Document was not yet applied for the active substance evaluation on EU-level on which the application for product authorisation is based. In principle, an evaluation of data according to the Guidance Document is not necessary but aggregate endpoints for degradation (DT50) and adsorption (Kfoc, 1/n) from the evaluation on EU-level (List of Endpoints) can be used as input parameters for modelling of predicted groundwater concentrations with FOCUS-PELMO.

Exceptions from this approach (i.e. use of aggregate endpoints from the EU List of Endpoints) are:

• New studies on degradation and/or sorption behaviour of active substance or metabolites are available which have not yet been evaluated in the procedure for active substance approval. In this case, a data matching procedure is required.
• The evaluation in the procedure for active substance approval exhibits apparent grave mistakes or is incomplete with regard to considering important aspects or significant new findings in the risk assessment (e. g. pH dependence of degradation and/or adsorption).

Other provisions of the Guidance Document, however, have to be followed in the zonal procedure for product authorisation, in particular using the crop interception factors specified in the Guidance.

Justification:

The results of the research project “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“ (2016) and the expertise “Comparison of different methodologies for selecting PELMO input parameters for groundwater modelling of plant protection products including current EU guidance (SANC0/12117/2014 - final, 2014)” (2017) have shown, that the different approaches used for the selection of input parameters (mean values according to Holdt et al., 2011) do not significantly influence the regulatory result of model simulations of predicted groundwater concentrations of plant protection products.

Thus, Germany, acting in the risk assessment for the authorisation procedure of the central zone, follows the agreed practice for the core assessment according to the Fate Working Document (Working Document of the Central Zone in the Authorisation of Plant Protection Products - Section 5 - Environmental fate and behaviour, rev. 1.0).

Consequences and follow-up

With this new approach Germany contributes significantly to the harmonisation of assessment methods as well as to the reduction of complexity within the environmental risk assessment in the context of zonal procedures of product authorisation.

Recommendations for the determination of data showing a pH dependence of degradation and adsorption and for the derivation of endpoints are currently being developed. For the selection of the scenario in the national groundwater assessment in the case of an pH dependence, the explanations in Holdt et al. (2011) apply.

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