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Salt Pollution

6-8, 9-12Data Exploration & NOS
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The Cary Institute has been involved in a long-term study to monitor the increase of sodium chloride in our local stream over the last 25 years.  While sodium is less of a problem for organisms, chloride can be more harmful. Unfortunately, chloride levels have increased in local streams throughout our region, and in many parts of the country, as municipalities treat increasing numbers of roadways with salt during the winter months.  Sodium chloride accumulates in groundwater over time, and is released into streams even during the summer, when groundwater plays a crucial role for supplying water flow.  So, despite the fact that salt is spread in the winter, it is a problem all year, and if current trends continue, many parts of the northeast will have streams with water that is unfit for human consumption and is toxic to freshwater life within the next century (Kaushal et al, 2005).   In addition to being a compelling environmental story, testing for conductivity as a measurement for chloride is relatively easy for students with a PASCO or Vernier probe, and samples can be taken from water bodies and stored conveniently for testing at a later date.