Communities in Horsham and Warminster, each with a former Navy base that became a Superfund site, are dealing with new water contamination problems from compounds previously used on the government properties.

The compounds, perfluorooctane sulfonate and perfluorooctanoic acid, are “extremely persistent in the environment and resistant to typical environmental degradation processes,” according to the Environmental Protection Agency.

“The toxicity, mobility and bioaccumulation potential of PFOS and PFOA pose potential adverse effects for the environment and human health.”

The Navy, in a release on the Warminster Municipal Authority website, said the compounds are associated with many consumer products and firefighting foams, such as those used at both the former Willow Grove Naval Air Station Joint Reserve Base in Horsham and the former Naval Air Warfare Center in Warminster.

Because of the discovery of the compounds in the drinking water at public and private wells in Warminster, the Navy is holding a public meeting from 5 to 9 p.m. Aug. 27 at William Tennent High School, 333 Centennial Road, Warminster.

The Navy said both Warminster public wells have been taken offline and the EPA is sampling private wells to take additional action, if needed.

In Horsham, wells number 26 and 40 that feed homes in a Sawmill Valley subdivision and along Keith Valley Road, were shut down.

The Horsham Water and Sewer Authority took the action after tests revealed PFOS detected at levels of 0.7 and 1.0 parts per billion in the two wells. The EPA has established a Provisional Health Advisory of 0.2 parts per billion. The authority coordinated with the EPA and the Navy to confirm the high levels.

The former firefighting training area of the base has high levels of PFOS and is not far from well 26, according to information on the authority’s website. “It is possible that the presence in groundwater is related to historic activities at the base.”

The situation in Horsham further complicates the Horsham Land Redevelopment Authority’s plan to acquire the property from the Navy.

Mike McGee, executive director of the HLRA, said the latest findings have “postponed the delivery of the property to us.”

The first parcel of property expected to be moved as early as the end of this year, which includes the runway and taxiway, won’t transfer until mid-2015 “if things go well,” he said. The date for the final of three parcels to be transferred was pushed back a year to 2021.

During a meeting of the HLRA board Wednesday, McGee called PFOA and PFOS “ubiquitous” compounds that are contained in things such as food wrappings and microwave popcorn.

There are 80 places that have elevated levels nationwide, he said, and 78 of them are airports. The two other sites are in Ohio and West Virginia, where the compounds were made.

The list of master developers to work with the HLRA in negotiations for the property with the Navy is down to four after Toll Brothers pulled out to partner with Lennar. The other contenders are Catellus Development Corp., Hankin Group and K. Hovnanian.

McGee expects the selection to take place by the end of the year or early next year.

W. William Whiteside, chairman of the HLRA board, said each of the four finalists have put forth plans consistent with the HLRA proposals.

“There’s not going to be any surprises when something is decided,” he said.