Georeferenced Probabilistic Risk Assessment of Pesticides

Abstract

The current exposure assessment for pesticide entries into water bodies considers a water body model which represents a realistic worst case for water bodies in the agricultural landscape. For the factors determining the pesticide exposure in the model a variety of deterministic assumptions are made such as that it is a stagnant water body of a default depth of 30 cm which is directly situated in the edge of the field. Although this scenariobased approach enables a protective risk assessment it does not allow for an estimation of the spatiotemporal occurrence of this exposure situation in the landscape. Spatially explicit information on location factors with a relevant impact on exposure and risk in a water body are missing and can therefore not be considered in the risk management. In contrast the use of geo-referenced probabilistic methods in risk assessment allows for a site-specific as well as quantitative characterization of the pesticide exposure and linked risks in water bodies. Consequently such approaches also establish the possibility for a spatially differentiated risk management. This again leads to the expectation that suchriskmitigationobligations due to their direct reference to the real local conditions might be more plausible and therefore acceptable for farmers. Furthermore they also give possibility to focus efforts in permanent local risk mitigation measures on those water body sections with a high risk.<BR>Quelle: www.umweltbundesamt.de

The current exposure assessment for pesticide entries into water bodies considers a water body model which represents a realistic worst case for water bodies in the agricultural landscape. For the factors determining the pesticide exposure in the model a variety of deterministic assumptions are made such as that it is a stagnant water body of a default depth of 30 cm which is directly situated in the edge of the field. Although this scenariobased approach enables a protective risk assessment it does not allow for an estimation of the spatiotemporal occurrence of this exposure situation in the landscape. Spatially explicit information on location factors with a relevant impact on exposure and risk in a water body are missing and can therefore not be considered in the risk management. In contrast the use of geo-referenced probabilistic methods in risk assessment allows for a site-specific as well as quantitative characterization of the pesticide exposure and linked risks in water bodies. Consequently such approaches also establish the possibility for a spatially differentiated risk management. This again leads to the expectation that suchrisk mitigation obligations due to their direct reference to the real local conditions might be more plausible and therefore acceptable for farmers. Furthermore they also give possibility to focus efforts in permanent local risk mitigation measures on those water body sections with a high risk.