DURANGO, Colorado — The toxic waste that gushed last week from a Colorado mine and threatened downstream water supplies in at least three states will continue to be dangerous whenever contaminated sediment gets stirred up from the river bottom, authorities said Wednesday, suggesting there is no easy fix to what could be a long-term public health risk.
The immediate impact of the 3 million gallon spill on Aug. 5 eased as the plume of contamination dissipated on its way to Lake Powell along the Utah-Arizona border. But the strong dose of arsenic, cadmium, lead and other heavy metals settled out as the wastewater traveled downstream, layering river bottoms with contaminants sure to pose risks in the future.
“There will be a source of these contaminants in the rivers for a long time,” said hydrologist Tom Myers, who runs a Nevada-based consulting business. “Every time there’s a high flow, it will stir it up and it will be moving those contaminants downstream.”
The U.S. Environmental Protection Agency had pushed for 25 years to grant Superfund status to the partly collapsed Gold King mine and other idled mines leaking heavy metals above the old mining town of Silverton, Colorado. That would have brought in major funds for a comprehensive cleanup.
But local authorities spurned federal intervention, leaving a smaller EPA-led team to investigate a small if steady stream of pollution. That team accidentally breached a debris wall at the mine, unleashing the pool of contaminated water that turned the Animas River yellow.
EPA Administrator Gina McCarthy, on a visit Wednesday to Durango, downstream of the spill site, said she had ordered agency personnel across the country to cease field investigation work on abandoned mines while the spill was investigated. EPA officials said they were seeking details on what the stop-work order means.
Long before the accident, mines in the Silverton area that were first developed in the late 1800s had been releasing steady streams of contaminated wastewater into area creeks, leaving some of them virtually lifeless. No fish swim where the runoff from the Gold King mine flows into Cement Creek and the upper reaches of the Animas River, which in turn feeds the San Juan River.
One week after the spill, the EPA said runoff had returned to its normal levels of about 213 gallons per minute. Agency cleanup crews hastily built a series of four sedimentation ponds, bulldozing mounds of earth and covering pits in plastic, to clean the runoff from the mine before it drains into the creek.
The agency said Wednesday that the ponds were reducing acidity and dissolved metals and that the runoff is now cleaner than it was before the spill. The ponds brimmed with yellow-tinted runoff outside the old mine, located 11,300 feet high in the Rocky Mountains.
EPA officials did not immediately respond to Associated Press questions about long-term dangers, but environmental regulators in downstream New Mexico warned that sediment gets kicked up by storms and high water, so it’s crucial to determine where the contamination settles.
“Those are some of the longer-term issues that affect humans as well as wildlife,” New Mexico Environment Secretary Ryan Flynn said.
Colorado and New Mexico officials teamed with the EPA to collect and sample fish for toxicity. While there have been no fish or bird die-offs, Flynn said that doesn’t mean the river is healthy or safe. He said more testing is needed.
Past mine waste accidents in the Rocky Mountains show the impact can linger for decades, said John Stednick, a watershed scientist at Colorado State University.
He cited efforts to clean up Colorado’s stretch of the Arkansas River that began with a 1982 spill, and the decades of fish kills after the Summitville Mine dumped wastewater into Wrightman Fork, near Del Norte, Colorado.
“It takes years for sediments to clean once acid mine drainage has been removed,” Stednick said.
The Gold King plume is already devastating to the Navajo Nation, which recently negotiated permission to pull San Juan River water through a $20 million treatment plant it’s building to provide a clean drinking resource to more of the 16,000 reservation families who still have to haul water to their homes.
Heavy metals were already present in the tribe’s groundwater, and “now those same things are dumped in the river,” complained Rex Kontz, deputy general manager for the Navajo Tribal Utility Authority. He estimated Wednesday that meeting EPA standards for clean drinking water could double the plant’s construction costs and require the tribe to spend millions more in operating costs each year.
The EPA said it will be Monday at least, but perhaps take weeks more, before test results can help show what hazardous material is in the water. The higher the concentrations, the higher the cost of removing heavy metals. And unlike some other Native American tribes, the Navajo are not swimming in casino cash.
“This new water coming in was the avenue to creating new development and creating long-term sustainability,” Kontz said. “Now it’s almost like your legs were cut out from under you.”
Navajo farmers are nervously waiting for someone to announce that it’s OK to irrigate their crops again. Just two weeks without water could wipe out their corn and alfalfa just before harvest, which represents an entire year’s salary for some farming families. Long term, they also worry that they will lose the ability to market their meat and produce as free-range and organic.
Some experts downplayed the damage. Ron Cohen, a civil and environmental engineering professor at the Colorado School of Mines, said he personally would swim or boat today in the Animas River, based on preliminary EPA data showing levels of metals decreasing in the 48 hours after the spill as the plume moved downstream.
But Cohen understands why others are waiting for more data. He has worked on EPA-funded projects and said the agency’s results must stand up in court, so it takes multiple test samples over time, and then subjects the results to more reviews.