Quantifying Atrazine Contamination in Minnesota Wetlands
Atrazine is a widely used herbicide in the cultivation of corn, with 33 million kg applied annually in the United States; in the early 1990's it was the most detected herbicide in surface waters throughout the US (Capel and Larson 2001). The estimated half-life of atrazine ranges from 42 days to 10 years, making it also one of the most persistent surface water contaminants (Hayes 2004).Concerns have been raised over atrazine functioning as an endocrine disruptor in aquatic systems, due to laboratory studies showing that concentrations of 0.1ppb or higher can produce gonadal deformities and hermaphroditism in frogs (Hayes 2004).However, the number of aquatic ecosystems in Minnesota with 0.1ppb or higher atrazine concentrations is unknown, as the most commonly used test has a detection level of 0.5 ppb. The Borgerding and Zimmer labs will work with undergraduate students to meet two objectives relative to atrazine. First, the Borgerding lab will develop a HPLC or gas chromatography (GC) procedure for detecting atrazine at ecologically relevant concentrations below 0.1ppb. Second, the Zimmer lab will collect water and sediment samples from 72 wetlands from across the "corn belt" region of western Minnesota. These samples will be analyzed using the newly developed HPLC or GC technique.Part of this second objective will include testing the hypothesis that atrazine concentrations increase with the proportion of land used for corn production in the wetland watershed.