Amy Adams of Appalachian Voices shows her hand after dipping it in the Dan River, Feb. 5, 2014. Gerry Broome/AP

Energy officials and environmentalists are making conflicting statements about the human and environmental safety of water in North Carolina’s Dan River, in which tens of thousands of tons of coal ash spilled from a defunct energy plant earlier this week.

Test results released late on Thursday by plant owner Duke Energy and the North Carolina Department of Environment and Natural Resources showed slightly elevated levels of arsenic and other toxins, but not at levels that would be harmful to human health.

But testing done closer to the spill site by a lab hired by environmental group The Waterkeeper Alliance showed arsenic levels almost nine times above the state’s results, and far above levels considered safe for human consumption.

Asked by The Associated Press why the state didn’t test closer to the spill site, Tom Reeder, head of North Carolina’s Division of Water Resources, said the results further downstream would provide more accurate results.

"Obviously, if we took it directly underneath where the discharge is entering the water, particularly in a case like this, you might find some exceedances," Reeder said. "But what we're really interested in is finding out what the actual impact is in the environment, and in order to do that you have to allow for some mixing so you get an accurate picture."

Activists said they believed the state and Duke Energy’s results, but questioned why testing wasn’t being done closer to the spill site.

“To me it sounds like they’re cutting Duke a break by going downstream where there’s going to be a dilution factor,” said Amy Adams, the North Carolina campaign coordinator at environmental group Appalachian Voices.

Adams and others said they didn’t need to look further than the inches-thick stew of coal ash floating down the river to know that environmental damage had been done.

“There’s a layer of very fine toxic coal ash around the Danville intake, and as you go up the river, it becomes 2, 4, 8, up to 10 to 12 inches of ash on the surface, and it’s slowly moving downriver,” she said.

The spill originated from a 27-acre pond of coal ash and slurry — the waste product of burning coal — at a closed Duke Energy power plant along the Dan River in Eden, N.C.

Hundreds of workers were still trying to cap the leaking pipe on Friday, which has so far allowed 82,000 tons of toxic ash and 27 million gallons of contaminated water to escape into the river. The flow is down to a trickle, but that’s mostly because there’s not much liquid left in the unlined coal pond.

The Dan River serves as the drinking water for about 17,500 residents of Danville, Va., and the intake pipe is just 15 miles from the Eden plant, but Danville and North Carolina officials said there were no signs that the filtered water was contaminated so far.

Danville Utilities received test results Thursday that show the city's water is safe to drink, a press release by city's utility company said.

The results were from raw water samples collected from the Dan River at the city's intake on Tuesday by Danville Utilities. It was tested for the presence of heavy metals.

The lab found no detectable levels of harmful metals, though it did say the level of iron exceeded drinking water standards. Iron is easily removed in routine water treatment, Barry Dunkley, division director of water and wastewater treatment for Danville Utilities said in the release.

But that's just a test on raw water — test results from water that had entered the distribution system after being treated were not in yet.

Adams said while the ash is the most visually obvious effect of the spill, she’s even more concerned about the millions of gallons of toxic water that’s likely made its way to the bottom of the river.

“It’s the dissolved metals that we’re most concerned about,” she said. “This is a toxic soup.”

Coal ash can contain a slew of dangerous chemicals like mercury, lead, arsenic and selenium.

"How do you clean this up?" Brian Williams, a program manager for the Dan River Basin Association told the Associated Press. "Dredge the whole river bottom for miles? You can't clean this up. It's going to go up the food chain, from the filter feeders, to the fish, to the otters and birds and people. Everything in the ecosystem of a river is connected."

Danville City Manager Joe King said in a statement Thursday that Duke Energy and the town had been in constant contact since Monday, and that Duke CEO Lynn Good had telephoned the town's mayor to "apologize for the incident."

This isn’t the first time a coal pond has caused environmental damage, and activists had pushed for years for North Carolina to more heavily regulate or close outright the unlined ponds, which often sit next to rivers.

In 2008, a plant in Tennessee spilled 5.4 million cubic yards of coal ash into a river and the surrounding area.

Duke Energy has also gotten in trouble for its coal ash storage before. Last year, North Carolina residents sued the company for continued coal ash contamination around the state. And a study published in August (PDF) found that Duke’s coal ash kills nearly one million fish a year in one North Carolina lake alone.

Given the company’s history of previous incidents in the state, environmentalists say they were surprised by the size of this week’s spill, but not surprised that it happened.

“There’s one surefire way to fix this: remove the coal ash from unlined pits near surface water,” said Amy Adams. “Every single one is a ticking time bomb.”