Roland Kubiak

Pesticide exposure assessment for surface waters in the EU. Part 1: Some comments on the current procedure.

In 2001, the European Commission introduced a risk assessment project known as FOCUS (FOrum for the Coordination of pesticide fate models and their USe) for the surface water risk assessment of active substances in the European Union. Even for the national authorisation of plant protection products (PPPs), the vast majority of EU member states still refer to the four runoff and six drainage scenarios selected by the FOCUS Surface Water Workgroup. However, our study, as well as the European Food Safety Authority (EFSA), has stated the need for various improvements. Current developments in pesticide exposure assessment mainly relate to two processes. Firstly, predicted environmental concentrations (PECs) of pesticides are calculated by introducing model input variables such as weather conditions, soil properties and substance fate parameters that have a probabilistic nature. Secondly, spatially distributed PECs for soil-climate scenarios are derived on the basis of an analysis of geodata. Such approaches facilitate the calculation of a spatiotemporal cumulative distribution function (CDF) of PECs for a given area of interest and are subsequently used to determine an exposure concentration endpoint as a given percentile of the CDF. For national PPP authorisation, we propose that, in the future, exposure endpoints should be determined from the overall known statistical PEC population for an area of interest, and derived for soil and climate conditions specific to the particular member state.

Pesticide exposure assessment for surface waters in the EU. Part 2: Determination of statistically based runoff and drainage scenarios for Germany

Abstract BACKGROUND In order to assess surface water exposure to active substances of plant protection products (PPPs) in the European Union (EU), the FOCUS (FOrum for the Co‐ordination of pesticide fate models and their USe) surface water workgroup introduced four run‐off and six drainage scenarios for Step 3 of the tiered FOCUSsw approach. These scenarios may not necessarily represent realistic worst‐case situations for the different Member States of the EU. Hence, the suitability of the scenarios for risk assessment in the national authorisation procedures is not known. RESULTS Using Germany as an example, the paper illustrates how national soil–climate scenarios can be developed to model entries of active substances into surface waters from run‐off and erosion (using the model PRZM) and from drainage (using the model MACRO). In the authorisation procedure for PPPs on Member State level, such soil–climate scenarios can be used to determine exposure endpoints with a defined overall percentile. CONCLUSION The approach allows the development of national specific soil–climate scenarios and to calculate percentile‐based exposure endpoints. The scenarios have been integrated into a software tool analogous to FOCUS‐SWASH which can be used in the future to assess surface water exposure in authorisation procedures of PPPs in Germany.

A simple approach for a spatial terrestrial exposure assessment of the insecticide fenoxycarb, based on a high-resolution landscape analysis

Abstract BACKGROUND The objective was to refine the standard regulatory exposure scenario used in plant protection product authorisations by developing a more realistic landscape‐related GIS‐based exposure assessment for terrestrial non‐target arthropods. We quantified the proportion of adjacent off‐target area in agricultural landscapes potentially exposed to insecticide drift from applications of the active substance fenoxycarb. High‐resolution imagery, landscape classification and subsequent stepwise analysis of a whole landscape using drift and interception functions were applied to selected areas in representative fruit‐producing regions in Germany. RESULTS Even under worst‐case assumptions regarding treated area, use rate and drift, less than 12% of the non‐agricultural habitat area would potentially be exposed to fenoxycarb drift above regulatory acceptable concentrations. Additionally, if the filtering effect of tall vegetation were taken into account, this number would decrease to 6.6%. Further refinements to landscape elements and application conditions indicate that less than 5% of the habitat area might be exposed above regulatory acceptable concentrations, meaning that 95% of the non‐agricultural habitat area will be unimpacted (i.e. no unacceptable effects) and can serve as refuge for recolonisation. CONCLUSION Approaches and tools are proposed for standardisable and transparent refinements in regulatory risk assessments on the landscape level.