PARENT SESSION

6A - LCIA - Toxicity/RA
Poster Hall
8:30 AM - Wednesday, 30 April 2003
Chair: Jolliet, O.¹, ¹
Co-chair: McKone, T.², ²

(WEP/230) Considering Pesticide Exposure via Leaching to Groundwater in LCIA.

Geisler, Georg¹, Hellweg, Stefanie¹, Hungerbuehler, Konrad¹, ¹ Swiss Federal Institute of Technology, Zurich, Switzerland

ABSTRACT- The LCIA of the agricultural use of pesticides should consider the exposure of humans and ecosystems due to the leaching of pesticides to groundwater. Many site-, use- and substance specific factors influence these complex exposure pathways. In this study, the variability of exposure due to the leaching of pesticides to groundwater was assessed. An event tree was set up to determine scenarios of maximum and minimum exposure. This event tree is parametrised specifically for a given crop. Firstly, potentially leaching pesticides were identified by their substance properties. Secondly, site characteristics including soil texture, annual rainfall and the presence of tile drain systems were specified. Finally, influencing factors from agricultural management were considered. For each scenario derived from the event tree, the mass of pesticide leached to 1 m depth in a field of 1 ha was simulated. We used the FOCUS-groundwater modelling framework for these calculations. The FOCUS-methodology, initially developed for Risk Assessment in the EU pesticide registration, ensured realistic and consistent model settings in all scenarios. The variability of the scenarios ranged from no leaching at all to leaching of around 5 % of the applied substance in worst cases, when substance properties, weather and soil type combined to favour the leaching of a pesticide. The scenario outcomes were underpinned by a literature review of field studies on pesticide leaching. Further, the fate of pesticides in the subsoil below 1 m and in the groundwater was estimated for a specific swiss aquifer. Exposure estimates for humans and ecosystems were calculated. These scores can be used as a mid-point indicator in LCIA. Integration of the exposure scores into existing LCIA-methods is discussed.

Key words: leaching, pesticide, groundwater, life cycle impact assessment (LCIA)