Geodata-based probabilistic risk assessment and management of pesticides in Germany: a conceptual framework

The procedure for the risk assessment of pesticides in Germany is currently further developed from a deterministic to a geodata-based probabilistic risk assessment (GeoPRA) approach. As the initial step, the exposure assessment for spray drift in permanent crops, such as vineyards, fruit orchards, and hops, is considered. In our concept, geoinformation tools are used to predict distribution functions for exposure concentrations based mainly on spatial information regarding the neighbourhood of crops and surface waters. A total number of 23 factors affecting the drift into surface waters were assessed and suggestions for their inclusion into the approach developed. The main objectives are to base the exposure estimation on a realistic representation of local landscape characteristics and on empirical results for the impact of each feature on the drift deposition. A framework for the identification of high-risk sites (active management areas [AMAs]) based on protection goals and ecological considerations was developed in order to implement suitable risk mitigation measures. The inclusion of active mitigation measures at sites with identified and verified risk is considered a central and important part of the overall assessment strategy. The suggested GeoPRA procedure itself is comprised of the following 4 steps, including elements of the extensive preliminary work conducted so far: 1) nationwide risk assessment, preferably based only on geodata-based factors; 2) identification of AMAs, including the spatial extension of contamination, the level of contamination, and the tolerable effect levels; 3) refined exposure assessment, using aerial photographs and field surveys; and 4) mitigation measures, with a focus on landscape-level active mitigation measures leading to effective risk reductions. The suggested GeoPRA procedure offers the possibility to actively involve the farming community in the process of pesticide management. Overall, the new procedure will aim at increased flexibility of pesticide application regulations and a high level of protection of surface waters.