Drinking-water well tests in north metro Denver have detected perfluorinated chemicals contamination at levels up to 32 times higher than a federal health advisory limit, forcing utility officials to dilute the tainted supply before it reaches people.

South Adams County Water and Sanitation District officials in early July conducted the tests and detected the perfluorinated chemicals, or PFCs, in 24 samples drawn from 12 municipal wells along Quebec Parkway near Interstate 270 — wells that feed up to 2,000 gallons a minute into district supplies for 50,000 residents across 65 square miles.

This is the first time PFCs — known to have contaminated water south of Colorado Springs — have been detected in municipal wells in metro Denver.

Colorado Department of Public Health and Environment officials on Thursday issued a notice but provided few details, saying the test data was proprietary and that state experts were not available. The Denver Post confirmed the contamination in talks with South Adams County Water and Tri-County Health Department officials.

“These were municipal supply wells. The range we found was 24 parts per trillion (ppt) to 2,280 ppt,” said Kipp Scott, the district’s water system manager.

The Environmental Protection Agency’s current health advisory limit for PFCs is 70 ppt because these are among the hardest-to-remove chemicals, linked to health problems from testicular cancer to low birth weights.

“Obviously, we had some wells above that level,” Scott said. “We have stopped using the three wells where the levels were highest. That’s out of an abundance of caution,” he said.

“Because of the wells, it is a concern. We’re taking steps to make sure that the (PFCs in) water delivered to customers remain below the health advisory number.”

EPA and CDPHE officials have told county officials they will help try to find the source of the contamination. That area includes numerous industrial and toxic cleanup sites regulated by state and federal agencies.

South Adams officials said they have begun purchasing Denver Water supplies, to be delivered through existing pipelines, and blending this into their municipal well water in order to reduce the PFCs concentration.

Tri-County health department officials who cover Adams, Arapahoe and Douglas counties planned to help identify more municipal and private wells that may be drawing groundwater contaminated with PFCs.

“We just want to try to assess the extent of what the potential concentrations of PFCs in the area may be. The district is doing some sampling. If we get calls in, we can try to determine if you are in the district or on a private well,” Tri-County’s environmental health division director Brian Hlavacek said.

“There are several wells — some supply wells, also some monitoring wells” where elevated PFCs were detected, he said. “We want to find out where it may be coming from. … I cannot see that there is anything specific. We’re trying to find out where it is coming from.”

PFCs can cause low birth weight, earlier puberty, diabetes and obesity. Exposure to PFCs also has been linked to cholesterol and liver enzyme problems leading to heart disease. Some research shows PFCs may be linked to kidney and testicular cancer. These chemicals have emerged as among the most problematic in a widening array of synthetic chemicals detected in water nationwide and cannot easily be removed due to their molecular structure.

Firefighting chemicals used for years at military airbases contained PFCs. Municipal firetrucks nationwide carried the foam. PFCs also are used in consumer products, including fast-food wrappers.

No government agency has systematically investigated health impacts.

For more than two years, CDPHE and EPA officials have been aware of PFCs contaminating groundwater south of Colorado Springs. That contamination has been linked to firefighting foam used on Peterson Air Force Base. It has contaminated groundwater tapped by utilities in Security, Widefield and Fountain. Full investigation of the harm in those areas still isn’t done, let alone environmental cleanup.

That area in southern El Paso County has ranked among the most populated of more than 70 places where utility tests revealed PFCs contamination at levels up to hundreds of times higher than the EPA health advisory limit, spreading mostly from military bases where aviation crews sprayed firefighting foam containing the chemicals.

EPA officials have said they will develop a national action plan for PFCs and that they are planning to visit Colorado to hear from residents.

There’s controversy around the EPA’s current limit. A federal Agency for Toxic Substances and Disease Registry study, which White House officials tried to suppress, proposes minimum PFCs risk levels that may require water concentration limits tougher than the 70 ppt limit.

CDPHE officials have relied on that EPA limit as the basis for a state limit that covers only the areas south of Colorado Springs. Thousands of people who for years relied on municipal well water in Fountain, Security and Widefield remain frustrated and fearful.