Drinking water across the county was tested for PFAS, or “forever chemicals,” in 2020. While all wells remain in regulatory compliance with Colorado’s standards for PFAS, changes to the Environmental Protection Agency’s standards put some in questionable status as local officials wait on more information from state and federal regulators.

Results from several wells showed signs of PFAS, but all were below the EPA’s former guideline of 70 parts per trillion. But on June 15, the EPA revised its guidelines to 0.004 parts per trillion for PFOA, 0.02 parts per trillion for PFOS, 2,000 parts per trillion of PFBS and 10 parts per trillion of GenX chemicals — four varieties of PFAS. That sent wells around the county outside the EPA’s health advisory recommendation.

In Frisco, its Well 7 tested at 6.2 parts per trillion for PFOA and 11 parts per trillion for PFOS. The Colorado Department of Public Health and Environment describes 1 part per trillion as a drop of dish soap in a 10-mile-long line of train water tankers.

As a health advisory, this new level is not federal regulation, and the Colorado Department of Public Health and Environment still regulates water by the 70 parts per trillion standard. According to the EPA, health advisories simply serve as technical information to assist government officials as well as managers of public or community water systems in protecting public health.

The EPA reports that studies have found associations between long-term exposure to all four chemicals and negative health effects. The EPA reports PFOA and PFOS exposure have been associated with effects on the immune system, the cardiovascular system and human development. One effect includes a reduced response to vaccines, leading to fewer antibodies.

GenX chemicals have been linked to health effects on the liver, the kidney and the immune system, as well as developmental effects and cancer, according to the EPA. The basis for the final health advisories for GenX chemicals comes from studies of liver lesions in animals linked to the chemicals.

Animal studies looking at oral exposure to PFBS have shown health effects on the thyroid, reproductive organs and tissues, developing fetuses and kidneys. The most sensitive noncancer effect and the basis for the final health advisory for PFBS is a decrease in thyroxine.

With the exception of PFBS, the other three varieties are possible carcinogens, but the EPA said proof is not conclusive.

Like Frisco and hundreds of other towns across Colorado, Silverthorne, Dillon and Breckenridge also participated in the test and its four wells all showed varying degrees of PFOA and PFOS, among other PFAS. PFAS captures a large class of widely used chemicals found in fabric, firefighting foam, nonstick surfaces and other products.

Silverthorne’s Eagle’s Nest well showed the highest total amount of PFAS at 14.29 parts per trillion. The Eagle’s Nest well also showed 2.7 parts per trillion of PFOS and 2 parts per trillion of PFOA. Both values were the highest among the four wells Silverthorne tested.

Dillon’s testing revealed no detected PFOS and 0.61 parts per trillion of PFOA. Dillon Valley’s testing also showed no detected PFOS and 0.54 parts per trillion of PFOS. Both Dillon and Dillon Valley take their water from Straight Creek, likely resulting in the similar findings, Dillon Public Works Director Scott O’Brien said.

Breckenridge also participated in the test, but it did not show a single detectable amount of PFAS at its lone testing site.

Silverthorne Town Manager Ryan Hyland said Silverthorne’s water hasn’t changed, but the conversation around it has. In other words, the water remains the same, but the EPA’s judgment of drinking water across the nation has changed.

Silverthorne has more testing for each well scheduled for the coming months. Currently the 2020 testing remains the only data point for the town to reference, Hyland said.

Hyland said it might not be worth speculating as to a cause since whatever source contaminated the wells probably isn’t around anymore. O’Brien also said Dillon wasn’t interested in pointing fingers at anyone.

O’Brien said Dillon is waiting on the Colorado Department of Public Health and Environment for further information and recommended action.

Hyland said Silverthorne is looking at filtration systems. It hasn’t made any plans for filtration upgrades and will wait on more information and recommendations from the EPA and Department of Public Health and Environment before proceeding.

“As water operators, we’re always looking to provide the best water,” Hyland said. “Should this become the standard, we’re all going to have to react.”