(CNN) The mustard hue of the Animas River in Colorado -- the most visible effect of a mistake by the Environmental Protection Agency that dumped millions of gallons of pollutants into the water -- is striking.

Just a glance at a photo of the orange-yellowish slush is enough to know that something seems wrong. Scientists will have to say just how wrong, and possibly dangerous, the contamination is, though five days after the spill answers are few.

Just how polluted is the river? Is drinking water in peril? Are businesses dependent on the river out of luck?

One question that has been answered is the size of the spill: more than triple than originally estimated. The U.S. Geological Survey reported the size of the spill to be more than 3 million gallons, compared with the initial EPA estimate of 1 million gallons.

Tom Bartles, who lives in Durango, Colorado shared these photos of the Animas River from the viewpoint of his backyard before and after the spill.

The EPA, which caused the accidental release of the contaminants Wednesday, said it continues to monitor the river.

"Collection, transportation and lab analysis of metals in water is complex and time-consuming," the agency said in a statement.

Cities in New Mexico are also at risk as the pollution flows from the Animas River into the San Juan River.

A flyover with a specialized aircraft showed that the conditions on the Animas and San Juan rivers between Durango, Colorado, and Farmington, New Mexico, have improved, the EPA said.

According to the EPA, the spill occurred when one of its teams was using heavy equipment to enter the Gold King Mine, a suspended mine near Durango. Instead of entering the mine and beginning the process of pumping and treating the contaminated water inside as planned, the team accidentally caused it to flow into the nearby Animas River.

'This is a really devastating spill'

Officials said they believe the spill carried heavy metals -- mainly iron, zinc and copper -- from the mine into a creek that feeds into the Animas.

Wednesday's spill caused a spike in concentrations of total and dissolved metals in the water, the EPA said.

According to sampling done by the EPA on various points along the Animas River Wednesday and Thursday last week, levels of lead, arsenic, beryllium, cadmium and mercury were extremely high compared with acceptable levels set by the agency, which are technically called "maximum contaminant levels" or "action levels for treatment."

One of the samples of mercury was nearly 10 times higher than the EPA acceptable levels. Samples of beryllium and cadmium were 33 times higher, and one of the arsenic levels was more than 800 times higher.

Exposure to high levels of these metals can cause an array of health problems from cancer to kidney disease to developmental problems in children.

"This is a real mess," said Max Costa, chair of the department of environmental medicine at New York University School of Medicine. "These levels are shocking."

According to the EPA, levels "began to return toward pre-event conditions" by Thursday. The agency has collected water samples from nine locations along the San Juan River where there are water intake plants.

River spill map

"This is a really devastating spill," said Kim Stevens, director of the advocacy group Environment Colorado. "We've been hearing from rafting companies and other businesses that rely on the river that if they can't get clients out on the river in the next couple of days, they may have to shut down their doors."

The rivers' ecosystems are also at risk, she said.

"The fish population is especially very sensitive to water contamination, and we really won't be able to see what the impacts are until all of the pollution has run its course. Time will tell what the true impacts are," she said.

The EPA and the New Mexico Environment Department said they will test private domestic wells near the Animas to identify metals of concern from the spill.

Tests on public drinking water systems are conducted separately by the state environment department, the agencies said.

'They're not going to get away with this'

Some people are upset at the EPA -- both for the initial spill and its response.

Navajo Nation President Russell Begaye has announced he intends to take legal action against the federal agency.

Photos: EPA spill turns Animas River orange Photos: EPA spill turns Animas River orange An EPA worker takes a water reading in the Animas River near Durango, Colorado, on Friday, August 14. The river reopened for recreational use Friday afternoon in La Plata County, Colorado, where an EPA crew polluted the waterway with mine waste on August 5, authorities said. Hide Caption 1 of 14 Photos: EPA spill turns Animas River orange The entrance area of the Gold King Mine is seen on August 14. Hide Caption 2 of 14 Photos: EPA spill turns Animas River orange A settling pond is used on Tuesday, August 11, in Silverton, Colorado, at Cement Creek, which was flooded with millions of gallons of mining wastewater. Settling ponds are used to reduce the acidity of mining wastewater so that it carries fewer heavy metals. Hide Caption 3 of 14 Photos: EPA spill turns Animas River orange The contaminated Animas River flows through Durango on August 7. Over 2 million gallons of mine wastewater made its way into the river, putting the city on alert. Hide Caption 4 of 14 Photos: EPA spill turns Animas River orange Tom Bartles shared views of the river from his backyard in Durango, before and after the spill. The before shot, on the left, was captured on August 6 when Bartles was aware the spill happened and was making its way down the river to Durango. The photo showing the "after" was captured on August 7. Hide Caption 5 of 14 Photos: EPA spill turns Animas River orange The spill caused a spike in concentrations of total and dissolved metals in the water, the EPA said. Matthew Evans shot this photo August 7. Hide Caption 6 of 14 Photos: EPA spill turns Animas River orange Evans shot these photos outside the Durango Riverside Resort. The top photo was taken on August 4; the bottom photo was shot August 7. Hide Caption 7 of 14 Photos: EPA spill turns Animas River orange Kayakers float along the Animas River near Durango, Colorado, on August 6, in water colored from the mine waste spill. Hide Caption 8 of 14 Photos: EPA spill turns Animas River orange "It was devastating to see this happen to our community. I was just in the river last weekend and we all love it around here," said Ryan Urban , who shot this photo in Hermosa. "Whenever there is any type of oil spill or waste in the water, it makes me hurt for the earth." Hide Caption 9 of 14 Photos: EPA spill turns Animas River orange Contaminated water accidentally released by the EPA turned a stretch of the Animas River orange. Hide Caption 10 of 14 Photos: EPA spill turns Animas River orange Durango resident Ian Lucier shot several photos of the river with his drone. Hide Caption 11 of 14 Photos: EPA spill turns Animas River orange "I got a text from a friend of mine in the morning asking if I had heard about or seen the river. At that point the orange water hadn't reached town so I headed north to see if I could find it," Lucier said. "When I first saw it, I was speechless, [the river] didn't look real." Hide Caption 12 of 14 Photos: EPA spill turns Animas River orange Authorities asked people to stay out of the water until EPA tests confirmed the contamination had dissipated. Hide Caption 13 of 14 Photos: EPA spill turns Animas River orange "This is so insanely tragic and absolutely crazy. It feels like something out of a sci-fi novel/movie," wrote Durango native Kristen Goldman . She shot this photo August 6 from the Dalton Ranch Bridge. Hide Caption 14 of 14

"They are not going to get away with this," Begaye said in a statement. "The EPA was right in the middle of the disaster and we intend to make sure the Navajo Nation recovers every dollar it spends cleaning up this mess and every dollar it loses as a result of injuries to our precious Navajo natural resources."

In a statement from NMED, state engineer Tom Blaine said that the EPA took no action to alert residents of New Mexico to the potential danger, and did not notify the state directly.

Colorado Gov. John Hickenlooper, meanwhile, declared a state-of-disaster emergency on Monday, a move that allocates $500,000 from the state's disaster emergency fund to pay for assessments and the response.

"Our priority remains to ensure public safety and minimize environmental impacts," the governor said.

"By declaring a disaster emergency, we are able to better support impacted businesses and communities with state resources. We will work closely with the EPA to continue to measure water quality as it returns to normal, but also to work together to assess other mines throughout the state to make sure this doesn't happen again," he said.