Page 24 - CBT 2018

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Photolysis as a pathway for pesticide processing in prairie potholes
Many prairie pothole wetlands are surrounded by agricultural fields to which pesticides are applied. These wetlands have shallow depths (< 2 m) and high concentrations (20–40 mg/L) of natural organic matter. Photolysis
is a pathway for pesticide destruction. Natural organic matter absorbs sunlight and generates highly reactive species that degrade pesticides. Reaction with excited state organic matter dominated the degradation of pesticides in prairie pothole wetlands. To predict the lifetime of pesticides in potholes, we need to know the spatial and seasonal dynamics of the production of reactive species. Permanent wetlands have lower steady-state concentrations of reactive intermediates than transient wetlands and also experience an increase in
the levels of reactive species over the growing season. This CEGE research highlights the importance of preserving wetlands for their capacity to degrade pesticides and provides information needed to predict pesticide persistence in the prairie pothole region. [27–29]