Image # 9717
Acid Runoff Iron Mountain Mine Superfund Site
The largest point source of highly toxic heavy metals in the nation feeds Spring Creek. The Iron Mountain Superfund site also releases the most highly acidic mine runoff on earth, running up to 100 times the concentration of battery acid. This acid drainage stains rocks with toxic heavy metal rich precipitates. The Iron Mountain mine ripped open the side of a mountain in search of iron silver, gold, copper, zink and pyrite. The abandoned mine left highly reactive iron pyrite exposed to the elements. Iron pyrite reacts with oxygen and water to form sulfuric acid. This causes massive leaching of heavy metals from the rock and soil it passes. Due to extreme toxicity to fish, a treatment plant and holding dam collect and reduce toxicity of the polluted rainwater. At times of sufficient flow in the Sacramento River the collected water is released. This alows high flows to dilute the toxic compounds enough that endangered salmon are not killed for miles downstream. This view taken just below the dam shows the treated water still precipitates significant quantities of minerals onto the rocks in Spring Creek. One of the largest settlements in the history of the Superfund was reached in October 2000. Nearly one billion dollars will be paid by Aventis CropSciences USA, Inc. for cleanup efforts during the next 30 years.