In late November, a flock of migrating snow geese landed in a lake in Butte, Montana. Soon, they began to die. Because what they landed in was the Berkeley Pit, a Superfund site filled with acidic and metal-laden toxic waste from copper mining. The lake was “white with birds;” thousands died. Weeks later, as the story has gone viral, officials are still counting.
The Berkeley Pit had killed migrating geese before. “It was a shock to hear it happening again, on a much larger scale,” says Andrea Stierle, who, along with her husband Don, has been studying the Berkeley Pit for more than three decades. In 1995, over 300 migrating geese landed in the pit and died from ingesting the toxic water. The Stierles were chemists at nearby Montana Tech at the time, and they were in search of microbes living in the toxic waste water that could make antibiotics and other useful substances. That arrival of the first flock of geese changed the microbial makeup of the Berkeley Pit and likely the outcomes of Stierles’ research, too.
The story of the Berkeley Pit isn’t a simple story of ecological disaster.
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There wasn’t supposed to be a lake here, let alone a toxic one. But in the Cretaceous period, when Montana was dotted with volcanoes, lumps of magma rose up through the Earth’s crust, bringing with them veins of ore rich in copper, silver, and gold. Seventy-five million years later—give or take a few million—humans stumbled on the precious metal near Butte. They came with their picks and axes, hollowing out tunnels for copper that built America’s electric grid in the early 20th century. When they dug out as much copper as they could from tunneling, they decided to turn the mine into an open pit.