EPA Spill of Toxic Mine Waste Three Times Bigger Than Originally Reported

08_10_2015_Gold King Mine EPA Animas River Spill
Yellow mine wastewater is seen at the entrance to the Gold King Mine in San Juan County, Colorado, in this photo released by the U.S. Environmental Protection Agency and taken August 5. EPA/Reuters

Four days after the federal Environmental Protection Agency accidentally released wastewater from an abandoned gold mine in Colorado into the Animas River, it emailed a revised estimate of the spill volume to reporters. A little over 3 million gallons of water laden with arsenic, lead and other metals had gushed out of the Gold King Mine site—three times the amount the EPA previously thought.

By Sunday night, the wastewater, which turned the Animas River a striking orange, reminiscent of boxed mac and cheese, had flowed south over the border into New Mexico and into the San Juan River, which converges with the Animas. That river system eventually flows into the Glen Canyon National Recreation area and Lake Powell, in Utah. As of Sunday night, the EPA said the plume was "in the vicinity" of the Navajo Nation boundary, near Kirtland, New Mexico, and Navajo officials issued a warning to residents not to use water from the contaminated source.

Initial EPA sampling verified that the plume caused a spike in metals like copper, lead, manganese, cadmium, arsenic and zinc. At its peak, arsenic concentrations were 300 times higher than the normal level, and lead was 3,500 times the normal level, The Guardian reported. The EPA noted that this spike "began to trend towards pre-event conditions" after the first 24 hours from when the plume passed a given stretch of river, but that more test results will be needed to know whether the drop in toxicity continues to safe levels.

As of noon Saturday, nearly 550 gallons of wastewater per minute were still flowing out of the scene of the initial incident. The EPA has constructed a series of settling ponds to collect the contamination near the site where its team caused the collapse of an earthen barrier on August 5, leading to the spill.

The EPA was investigating historic wastewater leakage from the mine, intending to set up a drainage system to stop the water from being discharged into a nearby creek, when its crew "hit a spot where water started coming out that we hadn't expected," Sean McGrath, the EPA administrator for the region that includes Colorado, said Friday at a community meeting in Durango, Colorado. "We come to find out there was quite a bit more mine wastewater up there than we had expected, for sure. In fact, the dam that had been holding that water back was just soils and loose materials instead of solid rocks. That started to flow out, and [the wastewater] quickly broke through and drained out."

The sheriff of La Plata County, Colorado, closed the river to the public, and the city of Durango, downstream from the mine, shut off its water pipes. Ranchers who use water from the Animas stopped using that water to irrigate their fields, The Durango Herald reported.

The long-term environmental impact of the spill is still unknown, and the EPA is waiting on lab tests. But at least one analysis came back as promising: The Colorado Parks and Wildlife Department placed three cages full of trout in the river, and in the first 24 hours, only one of the 108 fish had died. High Country News writer Jonathan Thompson notes that in 1975, when 50,000 tons of heavy-metal-laden mine tailings were accidentally spilled into the Animas, nearly all the fish in a similar test died within 24 hours. The river "looked like aluminum paint" for 100 miles downstream, wrote a Durango Herald reporter at the time.

For now, the EPA is working with local agencies to monitor water quality, and more test results are expected to come back from labs over the next few days.

"This is a huge tragedy. It's hard being on the other side of this. We typically respond to emergencies, we don't cause them," David Ostrander, the EPA's director of emergency preparedness for the region, said at Friday's community meeting. "But this is just an unanticipated situation that didn't quite come out as planned."