Greatest Water Quality Threat

A composite of two photos.  A picture of a heavy traffic jam within the Cades Cove Loop Road (left). A photograph of an active coal fire plant (right).
A composite of two photographs.  A heavy traffic jam on Cades Cove Loop Road within Great Smoky Mountains National Park (left). A picture showing an active coal-fired power plant with smoke stacks releasing billowing clouds of smoke (right).  

Photos courtesy of the National Park Service.


That's Right!

Nitrates (NO3) from car exhaust and sulfates (SO4) from coal-fired power plants are the major pollutants in the parks watersheds. (Robinson et al. 2005) The level of pollution input increases with elevation. Studies have shown that nitrate concentrations show no change over time even though ammonia and nitrate precipitation has been on the decline. (Robinson et al. 2006) Nitrates and sulfates contribute to acid rain because they form strong acids with the water in the atmosphere. Nitrate reacts with water to form nitric acid (HNO3) and sulfate reacts with water to form sulfuric acid (H2SO4). These acids fall to the ground with rain, which can cause dangerous drops in stream pH and stress out plants and trees making them more susceptible to insects and diseases.

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Last updated: April 14, 2015

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