Recent studies show that protected areas are exposed to pesticide loads from the agriculture that takes place in or around them. These can have an impact on biodiversity and water supply. Since the area of terrestrial biodiversity in protected areas and aquatic biodiversity in agricultural waters in general has already been considered in other projects, the present project will focus on aquatic systems in protected areas. For this purpose, data from several federal states on the application of pesticides, on the pollution situation in water bodies and on aquatic biodiversity in protected areas relevant for nature conservation will be evaluated and correlated. On the other hand, concrete evaluations are carried out for the exemplary analysis of a water system in the biosphere reserve Pfälzer Wald (Rhineland-Palatinate). In addition to nature or species protection, many protected areas have the specific function of providing water for drinking water production. In this context, data from several federal states on the application of pesticides and the pollution situation in water bodies in water protection areas will be correlated. In addition, the pollution of surface waters with pesticides will be measured using the example of water suppliers in Baden-Württemberg. Based on the specific protection goals, measures and strategies for a toxicity-based assessment of the loads and thus for targeted options for action to reduce the concrete problems associated with the use of pesticides will be developed and tested together with the practical partners in the field of nature and water protection.