ET-4G4 (2/10/05 version)
Chemical Integrity: Pesticides Case Study

Highlights / Details

  • The Upper Scioto River and Upper Big Walnut Creek serve as drinking water sources for the City of Columbus and surrounding communities. Both water sources have problems with seasonal atrazine run-off from agricultural operations;
  • Efforts to address the elevated atrazine levels and long pollutant residence time in Hoover reservoir resulted in the formation of the Upper Big Walnut Creek Water Quality Partnership and development of the Upper Big Walnut Creek Watershed Water Quality Management Plan
  • Management practices to control atrazine run-off have been in implemented extensively in the Upper Big Walnut, but not in the Upper Scioto watershed.
  • An initial comparison of water quality data for the Upper Scioto River and Upper Big Walnut during storm events showed atrazine concentrations in the Upper Scioto are more than double those in the Upper Big Walnut. These results provide some qualitative evidence of the effectiveness of management practices in the Upper Big Walnut.
  • Routine and expensive powdered activated carbon treatment of drinking water from the Scioto River continues to be necessary to remove atrazine to levels that meet drinking water standards. In contrast, it is not been necessary recently to use powdered activated carbon treatment on drinking water from the Upper Big Walnut to achieve drinking water standards for atrazine.
  • Several additional studies are underway to more quantitatively evaluate the effectiveness of atrazine management practices in the Upper Big Walnut.