As communities along the Animas River continue to wonder about the long-term consequences of the Gold King Mine spill, one of the biggest questions remaining is the orange sediment lying along riverbeds and riverbanks.

What’s in it? How long will it be there? How might it affect our drinking water and our health? These are all concerns for community members, and many experts say we may not know until time goes by and a few spring runoffs continue to wash it downstream.

The EPA says its initial testing on sediment samples taken from the Animas River between Bakers Bridge and North Durango show there is no risk to people from the sediment for recreational purposes. The agency released the results last week.

Many Durango residents who attended a public meeting the EPA held Thursday night asked about the metal levels in the sediment data only to be told that they should ask those same questions to the “experts” in a breakout session. Sediment and water quality was the most crowded breakout session.

At the session, EPA toxicologist Kristen Keteles said she used the maximum level in historical data she could find to show how levels of the different metals compare over the time humans have been measuring them.

“We based our safe-for-recreation numbers on what’s needed to protect children and high-exposure users,” Keteles said.

But Colorado School of Mines professor and toxicologist Dr. Danny Teitelbaum called the sediment data questionable.

The Durango Herald asked Teitelbaum to review the EPA’s post-Gold King Mine sediment data, as well as another data set obtained by the Herald containing EPA sediment testing from samples taken from the Animas River from sites between the Howardsville St. Gage Station – north of Silverton – and Bakers Bridge in 2012, 2013 and 2014.

Teitelbaum said those three-year results frequently showed elevated levels of lead and arsenic – two metals that pose major health concerns.

“There’s reason to worry based on that historical data,” he said.

But, he said, the EPA has provided so little information about the methodology it used when doing its Aug. 11 sediment sampling that it is impossible even for experts to discern whether there are unsafe levels of lead and arsenic in the sediment near Durango after 3 million gallons of contaminated wastewater from the Gold King Mine pulsed downstream.

“At this point, I don’t know whether to trust these results,” Teitelbaum said.

Specifically, he said, the EPA has not explained whether the recent sediment samples were extracted from the actual riverbed or the surface of the water.

On Saturday, after two weeks and multiple requests from the Herald, the EPA responded for comment about how the agency gathered and interpreted the sediment data. Agency scientists didn’t sample from either the surface of the water or the river channel but from the bank where people might physically come into contact with it.

“EPA has continued to collect sediment samples from the bank where sediment from the event is deposited and accessible to the public,” Senior Communications Officer Mark MacIntyre said in an email. “One set of samples is released and is available on the website.”

MacIntyre said the EPA is not sampling sediment from the main river channel, but it is sampling river water that would include suspended solids.

Three Region 8 EPA officials who were directly involved with sediment testing in the Animas River from 2012 to 2014 did not respond to phone messages requesting a fuller explanation of what the sediment tests mean, but the EPA did release information showing the average of all sediment tests taken between October 2012 and September 2014, well before the Gold King Mine incident.

Peter Butler, co-coordinator of the Animas River Stakeholders Group, said the Gold King Mine spill is not necessarily responsible for the levels of lead in the Animas River’s sediment, pointing to high levels of lead in the sediment lining the bed of the Animas above Silverton and the confluence with Cement Creek beneath Sunnyside Gold Corporation’s Mayflower tailings ponds. Those levels are higher than the elevated levels after the spill.

“The levels of lead there are as much as 10 times higher than those found near Durango after the spill,” Butler said testing in 2013 and 2014 showed, “and there are some brook trout living there.”

Larry Perino, a spokesman for Sunnyside, said in an email Saturday that “all of the former tailings impoundments have been completely reclaimed in accordance with applicable regulations. The source or cause of any elevated results in this segment of the Animas has not yet been determined.”

Teitelbaum said it’s vital for the EPA to establish, and the public to know, what, exactly, is in the riverbed, because all kinds of organisms feed off of it. “(The sediment) is biologically very active,” he said.

Metals are typically inorganic, meaning they are difficult for living organisms to absorb. But when metals get trapped in the layer of sediment lining the riverbed, plants and insects can convert them into organic metals, which are easily absorbed by other plants, animals and humans.

“That’s where the real risk lies in the river,” Teitelbaum said. “That’s persistent material that can get into the fish, plants and even the water supply.”

There are no hard and fast standards agreed on by scientists for metal loading in sediment. Teitelbaum said as a general rule, humans, animals, plants and other organisms can tolerate exposure to elevated levels of most metals – for instance, iron – for a short period of time, either by storing them in the body or getting rid of them.

Butler said he questioned whether Teitelbaum can say the levels of the metals are dangerous if there are no agreed-upon standards for metals in sediments. He also wondered how those metals might get into people’s bodies, particularly if there’s an advisory against eating fish caught in the Animas. Colorado Parks and Wildlife issued the advisory at the time of the spill and expects to have test results back soon on its first batch of tests of the fingerlings that were in the river during the height of the plume.

Over the long term, exposure to even small doses of many metals is dangerous. In fact, lead is a universal toxin, meaning that “no biological systems can tolerate lead without it having a toxic effect,” Teitelbaum said.

Clean-water standards allow for varying levels of zinc, magnesium and cadmium, but lead and arsenic are so poisonous that the EPA sets their maximum contaminant-levels goal at zero.

Teitelbaum worries about the levels of lead and arsenic that could potentially be present post-spill: “The big risks are birth defects and neurological effects on children, whose nervous systems are developing,” he said.

That would entail ingestion of the lead and arsenic, either by eating fish caught in the Animas or drinking water straight from the river. The city of Durango performs extensive tests on any of the water it pulls from the Animas, which is a small percentage of what it uses because it pulls the bulk of its water from the Florida River.

cmcallister@durangoherald.com. Herald Staff Writer Ann Butler contributed to this story.

Bakers Bridge sediment data (PDF)