Mustard-colored wastewater laced with heavy metals continues to drain into a river from an abandoned mine in southwestern Colorado at a rate of about 550 gallons per minute, according to the Environmental Protection Agency, which caused the spill.
The rate of discharge Saturday was down from about 740 gallons per minute on Friday. But three days after the massive spill, the agency said it still didn't know what the possible environmental and health impacts are.
The agency said it hoped to have a thorough lab analysis of the contaminants — which include lead and arsenic — as soon as Saturday evening or Sunday morning.
"We're busting our tails to get that out," Environmental Protection Agency Regional Director Shaun McGrath said. "We know the importance to people to have this information."
In the meantime, the EPA said it had finished building two containment ponds to treat the yellow sludge. However, the ponds are meant to immediately address the spill and cleanup efforts will likely take a long time. McGrath could not say whether that means days or weeks.
"This is a long-term impact. The sediment, the metals that are in that sediment are going to settle out to the stream bottom," he said. "As we have storm surges, as we have flooding events, that sediment can and likely will get kicked back up into the water. We're going to have to do ongoing monitoring."
About 1 million gallons of wastewater from Colorado's Gold King Mine began spilling into the Animas River on Wednesday when an EPA-supervised cleanup crew accidentally breached a debris dam that had formed inside the mine.
The mine has been inactive since 1923.
The plume reached the northern New Mexico cities of Aztec on Friday night, and Farmington on Saturday morning. Local government officials in New Mexico and Colorado have blasted the EPA, saying they didn't alert communities soon after the spill and that answers have been slow in coming.
"There's not a lot we can do. We can keep people away (from the river) and keep testing. We still don't know how bad it is," San Juan County Emergency Management Director Don Cooper said.
Officials in both cities shut down the river's access to water treatment plants and say the communities have a 90-day supply of water and other water sources to draw from.
No health hazard has been detected yet. In addition to lead and arsenic, federal officials say the spill contains cadmium, aluminum, copper and calcium, but the concentrations were not yet known.
Water samples were also tested in New Mexico, but no results have been released.
In addition to New Mexico, wastewater from the mine was also inching toward Utah.
The Animas flows into the San Juan River in New Mexico, and the San Juan flows into Utah, where it joins the Colorado River in Lake Powell.
Officials said the contamination would likely settle into sediment in Lake Powell. Glen Canyon National Recreation Area officials said visitors will be warned starting Monday to avoid drinking, swimming or boating on affected stretches of the lake and river until further notice.
The spill from the mine flowed down Cement Creek and into the scenic Animas River, which is popular with boaters and anglers. Aerial photos showed the slow-moving yellow water snaking by scenic mountain roads surrounded by pine trees.
While awaiting further results on the concentration levels of the metals in the water, the EPA released results Saturday showing how acidic the water became after the spill.
In Cement Creek, near the spill, the water registered a pH level of 3.74, which the EPA said is similar to the acidity of tomato juice and apples. Further downstream, in Silverton, pH levels were found to be about 4.8, which is similar to liquid black coffee.
The EPA warned people to stay out of the river and to keep domestic animals from drinking from it. Local officials declared stretches of the river off-limits in Colorado and New Mexico.
At least two of the heavy metals found in the waste water can be lethal for humans with long-term exposure. Arsenic at high levels can cause blindness, paralysis and cancer. Lead poisoning can create muscle and vision problems for adults, harm development in fetuses and lead to kidney disease, developmental problems and sometimes death in children, the EPA said.
When the spill happened, the EPA-supervised crew was trying to enter the mine to pump out and treat the water, EPA spokeswoman Lisa McClain-Vanderpool said.