(Prairie News Service) A new government study estimates nearly half of the nation's tap water has at least one type of Per-and Polyfluoroalkyl Substances (PFAS), also known as "forever chemicals," which may cause serious health issues. 

That's leading to renewed calls to eliminate these substances. 

The findings, issued this week by the U.S. Geological Survey, gathered samples from nearly 700 locations across the country. 

Five samples in Colorado – one from a private water source and four from public sources -  detected these chemicals, though the agency warns current testing methods can't capture all types of PFAS. State-level efforts have found low levels in some drinking water systems. 

No matter the amount, John Rumpler - clean water program director for the group Environment America - said all Americans should take these results seriously. 

"It's highly alarming, because these chemicals are toxic to humans at very low levels," said Rumpler. "And it's time to turn off the toxic tap and stop using these chemicals."

There's been growing research on the topic, but the USGS says its study is the first to carry out
large-scale testing of private and government-regulated public water supplies. 

While the Environmental Protection Agency is proposing some actions to limit the presence of PFAS in everyday products and water systems, some health and environmental groups say industries need to face more pressure to phase them out.

One of the EPA's recent responses is a proposed nationwide drinking water standard for selected forms of PFAS. Rumpler said this would help, but only scratches the surface. 

"There are literally thousands of these PFAS forever chemicals," said Rumpler, "and EPA is only proposing drinking water limits for a handful of them."

These chemicals have captured more attention because of emerging research on the health effects. The EPA notes that exposure could lead to increased cancer risks. 

Beyond detection in water systems, PFAS chemicals have been found in a range of products - including the linings of fast-food boxes and fire-fighting foam.