Special EESS talk on "Agrochemicals: On flow of water, pesticides and knowledge"


Event details

Date 20.06.2024
Hour 13:1514:15
Speaker Dr. Christian Stamm, EAWAG
Location Online
Category Conferences - Seminars
Event Language English
Clean water and healthy food are basic human needs. Unfortunately, providing both of them is often at odds. Agricultural production releases chemicals such as nutrients or pesticides into the (aquatic) environment to a degree that impairs water quality for environmental health and human consumption. To mitigate such negative effects and hence to minimize the trade-offs between agricultural production and water quality requires a proper understanding of the fate and transport of agrochemicals. How these chemicals move through the landscape though, is not a trivial task to solve. I present an overview about tracer experiments and field studies from plot to catchment scale that provided important insights into transport of phosphorus and pesticides. They demonstrate the importance of anthropogenic structures on fields and in the landscape such as hydraulic shortcuts that have often be neglected in transport models and mitigation strategies. These pathways often cause pronounced event-driven concentration dynamics in streams that are hard to capture with traditional sampling and measurement devices. New mobile instrumentation for on-site, real-time measurements of (organic) agrochemicals provide unprecedented insights into the complexity of source-flowpath combinations and the resulting concentration dynamics.To make such insights about transport processes relevant for practice and policy we have also to understand how knowledge flows between science and other actors. In the second part of the presentation, I present a general framework on evidence use in the context of pesticide policy and practice. Examples from the Swiss pesticide debate are used to illustrate how scientific evidence is used as means in political debates and how scientific observations may find their way into practical applications. An example from Uganda demonstrates the importance of transdisciplinary collaboration to identify key research questions that may subsequently lead to improved practices.
Although good research may reduce the trade-offs between clean water and the production of healthy food, these conflicts will hardly disappear completely. Therefore, it is also essential for the scientific community and the society at large to find formats to exchange about such trade-offs based on scientific evidence in a productive manner. I will finish with some observations from an ongoing Joint Initiative project in the ETH domain that addresses this science-policy dialogue

After studies in biology and a diploma in zoology at the University of Zürich, I left academia for some years working as a collaborator in  a private ecocenter „Schattweid“ and as freelancer. I returned to academic research for a PhD in soil physics at ETH Zurich studying phosphorus transport in grassland soils. Between 1998 and 2001 I split jobs between an Oberassistenz in Soil physics at ETHZ and the management of the conference organization „Centro Stefano Franscini“ of ETH Zurich on Monte Verità. In 2002, I moved to Eawag continuing to work on water quality impacts of agriculture with a specific focus on pesticides. Later my research diversified along different dimensions. On the one hand, I studied organic micropollutants from urban sources and their effects stream ecosystems. On the other hand, I was involved in several highly interdisciplinary projects including human health and political science perspectives related to micropollutants. Since 2023, I act as deputy director of Eawag.

Practical information

  • General public
  • Free
  • This event is internal


  • EESS - IIE


  • Prof. Tamar Kohn, Laboratory LEV


Transport preferential flow tracer experiments connectivity concentration dynamics stakeholders trade-offs evidence use