What Lives At The Bottom of Berkeley Pit?

Written by Niccoy Walker
Updated: December 19, 2022
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Butte, Montana, is a quaint, close-knit community near the majestic Rocky Mountains. But something destructive festers on the outskirts of town. A toxic, inhospitable lake threatens the animals and humans that call the area home. 

Discover what lives at the bottom of the Berkeley Pit, what happens if you drink its water and the dangers of living near a toxic site.

What is the Berkeley Pit?

Berkeley pit

The Berkeley Pit is a deep depression filled with toxic water from an old mining operation in Montana.


The Berkeley Pit is a deep crater filled with toxic water in the western United States. It is one mile long, 1800 feet deep, and contains highly acidic (2.5 PH) water, close to that of gastric acid. Between 1955 and 1982, it was an open-pit copper mine and extracted 17,000 tons of ore per day. 

After the mining company closed the pit, they shut the water pumps off, and the groundwater from nearby aquifers slowly started to fill the depression by a foot per month. The water gets its acidity from the heavy metals and chemicals within the pit, like sulfuric acid, arsenic, zinc, and copper. Copper is severely toxic in large quantities, and the amounts are so high at Berkeley Pit that you could mine for copper directly from the water. 

This deadly pit is one of the largest superfund sites in the country, but surprisingly, it’s also a tourist destination. For a small admission fee, you can look out over the pit at the viewing platform and visit the gift shop before leaving.

What Happens if you Swim in the Berkeley Pit?

The water in Berkeley Pit is highly toxic to your health. You can not swim in it or drink from it. While no humans have ever tried to swim in the pit, examination of deceased birds confirms they died of high levels of arsenic and copper. These chemicals and metals burned their insides and produced festering sores. 

So, how did the Berkeley Pit become one of the deadliest places on earth?

How Did the Berkeley Pit Form?

Botswana diamond mine

The Berkeley Pit is as acidic as gastric acid or lemon juice and a dead zone for animals and plants.

©Lucian Coman/Shutterstock.com

Butte, Montana, “The Richest Hill in the World,” was a thriving mining town and one of the wealthiest communities in the country. The post-war boom created a demand for items like cars, radios, TVs, and phones. And the main ingredient needed? Copper. 

The mining company switched its operations to open-pit mining when it became too costly to run underground mines. The miners extracted over a billion tons of copper ore, gold, and silver. And when groundwater began draining into the pit, the company installed water pumps to keep it out. It was all well and good until the mining operation closed up shop and turned the pumps off. 

Rain and groundwater began filling the deep depression, and the water was leaching out metals from the rock. Eventually, the water became dangerously acidic and laden with heavy, toxic metals. You won’t find fish swimming in this “lake,” not even insects buzz about this noxious stew. It is a dead zone in a family-friendly community. But it makes you wonder, is there any sign of life within its deep, deadly water?

What Lives at the Bottom of the Berkeley Pit?

Fungi, protists, algae, protozoans, and bacteria

live at the bottom

of the Berkeley Pit.


Extremophiles like fungi, protists, algae, protozoans, and bacteria live at the bottom of the Berkeley Pit. The water is much too hazardous for normal aquatic organisms, but toxic sites like this are an ideal environment for extremophiles.

Researchers once believed that life could not exist in a superfund site as lethal as the Berkeley Pit, but a chemist noticed a green slime floating on the water’s surface in 1995. Scientists studied the slime and discovered it was single-celled algae, a protozoan able to alter its environment to something hospitable. 
Cancer researchers are currently studying extremophiles like the ones in the Berkeley Pit. Organisms such as the ‘swimming water bear’, or tardigrade, thrive in uninhabitable places and can even restore their damaged DNA. A research team identified over 160 species of extremophiles from the Berkeley Pit (some never seen before), and their discovery led to several promising chemicals. When tested on brine shrimp, the chemicals slowed the growth of lung cancer cells. More research is needed, but it is a very promising revelation.

Could the Berkeley Pit Overflow and How is it Being Monitored?

While it’s interesting to learn about toxic superfund sites and the dangers that surround them, it’s important to keep in mind the reality of the situation. Could the Berkeley water pit ever overflow? No.

The pit fills with groundwater, which cannot flow upward. Not to mention, city officials pump, treat, and discharge the toxic water to keep the levels under control. Water levels are measured monthly and chemistry samples are taken twice a year. Scientists closely monitor the Berkeley pit to understand how it is moving underground and how to continue treating it moving forward.

What is Being Done About the Berkeley Pit?

Berkely Pit

Montana officials are pumping out water from the Berkeley Pit, running it through a treatment plant, and discharging it.

©PhilAugustavo /Shutterstock.com

Other than continuously monitoring water levels, officials pump and treat the contaminated water before discharging it to nearby surface waters. This process keeps the water level well below critical levels at all times, ensuring the safety of all residents.

The photo featured at the top of this post is © iStock.com/dottedhippo

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About the Author

Niccoy is a professional writer for A-Z Animals, and her primary focus is on birds, travel, and interesting facts of all kinds. Niccoy has been writing and researching about travel, nature, wildlife, and business for several years and holds a business degree from Metropolitan State University in Denver. A resident of Florida, Niccoy enjoys hiking, cooking, reading, and spending time at the beach.

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