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Living Downstream

Atrazine and Coliform Bacteria Effects on Water Quality - A Debate Case

Thomas A. Davis
Division of Molecular and Life Sciences
Loras College


In this case, developed for a course in Issues in Environmental Biology, students learn that water samples collected from a local river show elevated levels of fecal bacteria and atrazine, one of the most commonly used herbicides in the United States.  A hearing has been called by the county to investigate the cause of the contamination, possible effects on aquatic life in the river, and what can be done to prevent a recurrence. In the ensuing debate, students must analyze and interpret data as they present the viewpoints of various stakeholders, ranging from the landowners' right to apply atrazine to control weeds, to the responsibility of fisheries biologists and water quality specialists to protect the environment.


  • Be able to discuss both sides of a contemporary environmental issue and see how science is involved in producing data and information that is vital to making a decision; as part of this, students write an essay that states their position and explains why they feel that way.
  • See how the scientific method, equipment, data, and results are used to solve everyday environmental problems.
  • Be able to interpret scientific data in graphical or table form and apply it to help understand and solve an environmental problem.


Atrazine; herbicide; coliform bacteria; fecal coliform; benthic macroinvertebrate; water quality monitoring

Educational Level

Undergraduate lower division, Undergraduate upper division



Type Methods

Debate, Role-Play



Subject Headings

Environmental Science Agriculture

Date Posted


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