ATRAZINE LEVELS IN IOWA LAKES AND RIVERS

  Brent Nichols, Jacob Becker and Duane Bartak 

   Atrazine is the most commonly used herbicide in Iowa.  In addition to its effects on weeds, it is known to have negative effects on non-target organisms, including humans.  Atrazine levels in Iowa lakes and wetlands were tested using solid-phase extraction and high-performance liquid chromatography.  Samples sites included the following lakes:  Silver (Delhi, IA), Corydon (Corydon, IA), LeShane (Lamoni, IA), Loch Ayr (Mt. Ayr, IA), Morris (Chariton, IA), Rathbun and Walton (Fairfield, IA), and the Beaver Valley Wetlands (Cedar Falls, IA).  Water samples were filtered and underwent solid-phase extraction, concentrating the samples 1000 fold.  Atrazine could then be detected at 0.05 – 15.0 ppb with a recovery rate of 93-104%.  Atrazine is moderately persistent and was detected in water samples throughout the summer; concentrations tended to decline after the end of the seasonal application cycle.  In most of the samples tested, levels were < 3 ppb, which is below the EPA’s criteria for drinking water.  Significantly higher concentrations were found at two of the southern Iowa sites:  Loch Ayr and Lake LeShane.  Land use practices in this part of the state should be investigated to determine whether atrazine concentrations in these water bodies can be decreased, as they pose a risk to humans and wildlife.  Further studies should also investigate the effects of crop rotation on pesticide contamination in surface water bodies.

This research was supported by the Roy J. Carver Charitable Trust and the Iowa Space Grant Consortium.