Saturday, May 16, 2009

Case Study: Ducktown, Tennessee

One of my favorite environmental stories centers on Ducktown, Tennessee, where native copper was discovered in 1843, and where since 1854 metal sulfides mined from the Copper Basin were smelted in ovens to separate the copper [1], [2]. Trees from the local hardwood forests fueled the ovens, which emitted sulfur oxides that combined with water in the air to form sulfuric acid. The acid stung the eyes, damaged the lungs, killed local vegetation, and leached nutrients from the soil. Without vegetation, the soil eroded away, leaving behind a thin layer of hard, red, infertile soil covering the rocks. Thus, the area surrounding Ducktown looked like the surface of Mars for many decades; U.S. astronauts said it was one of the most recognizable features on the surface of the earth. For environmentalists the good part of the story is that, by 1903, the mining companies figured out how to reduce the environmental damage caused by smelting and at the same time make more money. They simply collected the sulfur oxides released during smelting, added water to make sulfuric acid, and then sold the acid for more money than they made from selling the copper. This is an example of one of those rare “win-win” situations that businesses should always look for.

Since the 1930’s the government has been trying to revegetate the Ducktown area to reduce erosion and the amount of toxic heavy metals being dissolved and transported into local streams [2]. However, the soil is so acidic and infertile that almost nothing will grow in it except a few hardy pine species.

1. Keller, E.A., Introduction to Environmental Geology. 3rd ed. 2005: Pearson Prentic Hall. 583.

2. Kaufman, D.S., The Effect of Pine Afforestation on Copper and Iron Movement Through the Recovering Soils of the Copper basin Mining District, Ducktown, Tennessee, in Geology. 1999, Vanderbilt University: Nashville, TN. p. 135.

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