Officials present preliminary data at public meeting in Durango, Colo.
FARMINGTON — Officials from the Environmental Protection Agency said Sunday that the Gold King Mine discharged an estimated 3 million gallons of contaminated water, three times the previous estimate.
The mine continues to discharge 500 gallons per minute, EPA Region 8 administrator Shaun McGrath said in a teleconference call Sunday afternoon, but the polluted water is being contained and treated in four ponds at the site of the spill near Silverton, Colo.
According to preliminary testing data the EPA released Sunday, arsenic levels measured in the Animas River in the Durango area peaked at 300 times the normal level, and lead peaked at 3,500 times the normal level. Officials said those levels dropped significantly after the plume of contamination moved downstream.
Both metals pose a significant danger to humans in high concentrations.
"Yes, those numbers are high and they seem scary," said Deborah McKean, chief of the Region 8 Toxicology and Human Health and Risk Assessment. "But it's not just a matter of toxicity of the chemicals, it's a matter of exposure."
She said the period of time those concentrations remain in one area is short.
However, McGrath said the EPA is looking at the possibility of long-term damage related to toxic metals falling out of suspension as the plume slowly moved along the river.
"Sediment does settle," McGrath said. "It settles down to the bottom of the river bed."
McGrath said future runoff from storms will kick that toxic sediment back into the water, which means there will need to be long-term monitoring.
He added that "the Animas River has historically been polluted by acid mine drainage."
Mustard-colored water loaded with heavy metals, including arsenic, lead, copper, aluminum and cadmium, began rushing out of the Gold King Mine at 10:40 a.m. Wednesday after an EPA team disturbed a dam of loose rock lodged in the mine.
The deluge of polluted water poured into Cement Creek and continued into the Animas River. The plume of pollution, clearly visible from the air and estimated to be more than 80 miles long at one point, reached Farmington on Saturday morning.
Federal, state and local officials in Colorado attended a public meeting Sunday night at Miller Middle School in Durango, where they presented preliminary data on the pollution's impact.
Marcie Bidwell, executive director of the Mountain Studies Institute, a nonprofit ecological research institute based in Silverton, said the pH level of Animas River water in the Durango area had stabilized at safe levels by Sunday.
Scott Roberts, an aquatic biologist for the institute, said most of the river's macroinvertebrates are still alive after initial exposure to the pollution plume.
Macroinvertebrates are acutely sensitive to changes in the environment and therefore good indicators of water quality and river health, the researcher said.
He said, however, their long term health will need to be studied.
McKean said at the meeting the EPA is in consultation with several other agencies, including the Center for Disease Control, to determine when the river will again be safe for recreation.
She could not say when that decision will come when asked by an attendee during the question-and-answer portion of the meeting.
Daniel Silva, a 37-year-old resident and local fisherman who attended the forum, accused EPA officials of "terrorism" for their part in causing the spill.
McGrath said such an accusation was "really not appropriate."
"We are not in the business of creating these types of messes," McGrath answered. "We are used to cleaning up these types of messes."
Richard Ruth, a local lawyer, asked whether a federal Superfund designation would be appropriate for the Upper Animas Mining District.
"We are in discussion about it," McGrath said. "I am hopeful."
McGrath said that listing the site on the National Priorities List, is only one option, however.
According to the EPA's website for the Upper Animas Mining District, environmental officials considered adding the Upper Cement Creek area to the National Priorities List in 2008, but decided against it due to a lack of community support.
Such a designation would establish the area as an abandoned hazardous waste site and provide access to federal funds to implement a comprehensive cleanup plan. However, some residents reportedly were concerned about negative impacts on tourism.