FOOTPRINT Project papers cont.

Nolan, B.T., Dubus, I.G., Surdyk, N., Fowler, H.J., Burton, A., Hollis, J.M., Reichenberger, S. and Jarvis, N.J. (2008). Identification of key climatic factors regulating the transport of pesticides in leaching and to tile drains. Pest Management Science, 64(9): 933-944.

We identified key climatic factors influencing the fate of pesticides in the environment as part of an ongoing risk assessment for the European Union. Climatic zonations for fate modelling were previously based on average annual temperature and rainfall. Other climate characteristics, such as the timing of rainfall in relation to pesticide application, may be more critical. We simulated the fate of three pesticides, nine contrasting soil types, two application periods, five application dates, and six climatic data series using the pesticide leaching model MACRO. The climatic data were then characterized in detail with regard to rainfall and temperature patterns before and after pesticide application. Predicted cumulative pesticide loads were analyzed and related to climatic variables using statistical methods. Soil type was a dominant factor controlling pesticide loss in both leaching and drainage scenarios. Clay soils were consistently associated with upper-quartile pesticide losses (>0.046 mg/m² for leaching and 0.042 mg/m² for drainage). Winter rainfall influenced losses of less mobile and more persistent compounds, while short-term rainfall and temperature controlled the more mobile pesticides. Climate interacted strongly with soil type under both leaching and drainage scenarios. The influence of short-term climatic variables and the timing of extreme events in relation to pesticide application were greater for drainage scenarios than for leaching, which is consistent with the rapid transport of pesticide via macropores in fine-textured soils. Climatic factors identified here are being used to refine climatic zonations representing the European Union.

Contact:

Dr Igor Dubus
FOOTWAYS SAS
10 Avenue Buffon
45 071 Orleans Cedex 2
France

Email: igor.dubus@yahoo.com