Ask Eartha: Understanding the long-term effects of river pollution |

Ask Eartha: Understanding the long-term effects of river pollution

The Animas River ran milky orange after a blow-out at the Gold King mine near Sivlerton recently.
Jonathon Thompson / High Country New |

Dear Eartha,

I am so concerned about the effects of the Animas River pollution. Can you explain how this happened, and what the effects on the biology of the river will be? — Peggy, Breckenridge

Peggy, your anxieties about this toxic spill are totally valid. The high concentrations of heavy metals released into the Animas River last week are a huge cause for concern. For those who are not aware, Environmental Protection Agency (EPA) contract workers inspecting and working on the abandoned Gold King mine near Silverton accidentally spilled 3 million gallons of contaminated mine water into the Animas River.

Ironically, the EPA workers were investigating how to keep the polluted water from spilling into the river because they had noted the polluted water — held by a make-shift dam — was rising and posing to breach the dam. According to High Country News, the fluid was being held behind unconsolidated debris, and the EPA workers triggered the spill while using heavy machinery to inspect the pollutants at the abandoned mine site. The result was millions of gallons of an orange-liquid laden with heavy metals flowing down and further polluting the Animas River.

The river flows down from Silverton through Durango and on to Utah and Arizona. The pollution of the spill could have larger implications for aquatic and wildlife, but, so far, the effects have been minimal. However, environmentalist like Rodger Clark, executive director of the Grand Canyon Trust, say that the effects of the spill could be felt for years, as the heavy metals bio-accumulate within the food chain.

Despite causing a spill, the EPA workers were not the definitive root cause of the pollution: Pollution is not new to the Animas and has had a long history of being polluted by human activity. According to High Country News, the Upper Animas Watershed is a collapsed core of an ancient volcano and is highly-mineralized. Miners have been after the precious metals since the 1870s, and mines simply poured their tailings into the river until the 1930s when downstream farmers forced the mines to stop this practice. Acidic mine drainage into the Animas Watershed is also a huge source of heavy metal pollution to the Animas. Portals and shafts blasted in the surrounding rock disrupt the natural water flows and forces drainage to flow out through the resulting fractures in the rock. There, the water reacts with iron disulfide (pyrite) and oxygen to form sulfuric acid and then dissolves to form zinc, lead, cadmium, copper and aluminum in the water that flows out of the mine shafts. In 1991, when the last of the mines in the area were shut down, there were around 400 mine shafts draining into the Animas River watershed, and no fish could be found for miles around the Durango area.

Cleanup efforts have ensued in the years since the last mine was closed. For every step forward, there have been a few set-backs. In the early 2000s, metal levels had dropped significantly, and fish returned to the area. However, as soon as more mine drainage was capped shortly after the heavy-metal-laden waters returned to the rivers, aquatic life numbers declined again. So, while the EPA was not the root cause of the pollution in the river, they have added to a problem that has had a presence since the early twentieth century.

The short-term effects of the pollution are showing signs of not being so severe. The acidity of the water was drastically reduced when the polluted waters mixed with the Animas River water. The U.S. Fish and Wildlife Service conducted an aquatic life test that involved putting 108 fish in the waters, and only one out of the 108 fish perished in the study. But, the long-term effects are still unknown, and the spill is causing economic impacts on the river tourism industry in the height of their season as a result. In addition, there is the valid concern for the drinking water in the area. Some residents have reported the yellow-orange color present in their well water, but no report has been issued on drinking water quality at the time of this article.

The positive side of this disaster is that there is now national spotlight on acidic mine drainage and heavy metal pollution and its effects on the environment. The Animas River watershed has been in consideration to be a Superfund site for years. Now, that might become a reality and free up millions of dollars for cleanup efforts.

Here in the High Country, we are all too familiar with heavy-metal pollution in sites like the Snake River. Perhaps out of this disaster will come new knowledge for how to deal with these situations. A disaster is never what is wanted for our precious home state. Yet, bringing national attention to an issue that has been in the hearts and minds of Coloradans for years could offer new insight and support for clean-up efforts everywhere.

Ask Eartha Steward is written by the staff at the High Country Conservation Center, a nonprofit organization dedicated to waste reduction and resource conservation. This guest entry was written by a Summit County Master Gardener. Submit questions to Eartha at eartha@highcountry

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