Assessment of the pesticide leaching risk at the Pan-European level. The EuroPEARL approach

Abstract

Contamination of the groundwater is an important side-effect of the usage of plant protection products in agriculture. Today, the use of plant protection products that potentially contaminate the groundwater is banned by registration procedures at both the European level (Council Directive 91/414/EEC), and the level of individual member states. The Directive places great importance on the use of models to calculate Predicted Environmental Concentrations (PECs) as a basis for assessing the environmental risks. In the first tier of the current procedure, point scale leaching models are combined with a limited number of worst-case scenarios to assess PEC groundwater in Europe.

An alternative procedure would be to use spatially distributed leaching models. Such models provide policy makers with a wealth of additional information, allowing identification of high and low risk areas in terms of spatially varying environmental and land use properties. In this study, such a spatially distributed leaching model, the EuroPEARL model, was implemented to assess the leaching risk of plant protection products at the Pan-European scale. This model is one of the products that has been delivered within the framework of the APECOP project (FP5-QLK-1999-01238), which is a European project supporting the harmonised registration of plant protection products in Europe. Simulations were performed for 1062 unique com-binations of Soil Mapping Unit, Climate Zone and Country. Soil properties, including soil horizon des-ignations, were obtained from the Soil Profile Analytical Database of Europe. Daily weather data were obtained from the MARS database.

Other data like irrigation data, crop data and product properties have been compiled from various sources, such as inventories, field-studies and the literature. The 1062 unique combinations together represent 75% of the total agricultural area of the European Union. Aus-tria, Sweden and Finland could not be included in the simulations, because there was insufficient soil profile information for these countries.

Results are presented with a resolution of 10x10 km2, which is the highest justifiable resolution based on the EU soil map 1:1,000,000. The Pan-European results con-firm that the predicted leaching concentration generally increases with precipitation and irrigation and decreases with increasing organic matter content. Because of the strong sensitivity of the leaching con-centration to soil properties, there is a strong variability of the calculated leaching concentration at rela-tively short distances.

Results further indicate that due to large irrigation amounts combined with large temporal variation of rainfall in the Southern European countries, the trend in the calculated leaching risks from North to South was less than expected. This implies that areas of high leaching risk (‘hot-spots’) as assessed by means of the EuroPEARL model occur in all countries of the European Union, including the Southern European countries.