“Davis-Monthan Air Force Base admits it allowed some toxic chemical compounds used for firefighting to wash into the soil and discharged the compounds in diluted form into sewers.

But until the base finishes an investigation this fall of its use and disposal of the compounds, D-M officials said they’re not ready to say whether their use of per- and polyfluoroalkyl substances, or PFAS for short, contributed to contamination of two city of Tucson drinking water wells lying to the north.

The base, like many others around the country, used these compounds in firefighting foam for more than four decades — from 1971 until last year, a D-M spokesman said in a written statement. Most commonly, the compounds used were PFAS varieties known as PFOS and PFOA, neither of which is legally manufactured in the U.S. today due to ongoing and increasing concerns about their health risks…

Tucson City Councilman Steve Kozachik, who first told the Arizona Daily Star about the city well contamination, said the base’s statement amounts to an admission of culpability. Even before D-M finishes its investigation, base officials should meet with Tucson Water officials ‘immediately’ to start work on a plan to clean up the city wells, Kozachik said in an interview.

In city well samples taken last October and in March 2018, levels of the compounds ranged from 97 parts per trillion to 3,320 parts per trillion. That compares to an Environmental Protection Agency health advisory level of 70 parts per trillion.

‘We now know it wasn’t a bunch of guys sitting at the end of a runway washing Teflon pans,’ said Kozachik, referring to another common use of these compounds, in non-stick products. ‘The public is concerned about this. I’ve gotten calls and emails from people who want this addressed, and not in the early fall.

‘They need to be sitting down right now with Tucson Water … not studying it till fall, and coming up with some sort of boilerplate bureaucratic response that, ‘We can’t determine cause and effect,’’ said Kozachik.

He added that the base’s acknowledgment that some of the compounds washed into the soil makes for ‘pretty easy dots to connect.’

Base officials, however, say they must first determine if these compounds were released at specific sites on the base.

Historical evidence and interviews of base personnel done for a preliminary assessment only suggest that the foam was used in specific locations, said base spokeswoman Lt. Lauren Gao. An ongoing site inspection, through sampling and testing, will verify if and how much is present in those locations, Gao said…

A 2015 report for the Air Force identified one fire-training area on the base where a ‘high mass’ of firefighting foam was released. At that site, training activities were conducted at ‘unlined burn areas’ from 1968 to 1986, and firefighting foam was used there for weekly and monthly training during roughly the same period, the report shows.

At four plane crash locations, unknown or small amounts of firefighting foam were applied, and the foam was left to evaporate or dry out, the report said.

At an unlined stormwater drainage canal, an unknown amount of firefighting foam was released into the environment, the report said. Materials were received in the canal from ‘washouts’ of foam material conducted at two flight aprons on the base, along with surface water from various locations including, possibly, foam materials from the four plane crashes.

As for the sewers, the same report says that wastewater from hangars and fire stations is routed by pipelines to a wastewater plant on site that pre-treats industrial waste for discharging.

The treatment plan removes oil, grease and heavy metals before transporting the effluent off the installation to the Tucson Diversion Channel, a flood-control channel.

That channel, in turn, empties into Pima County’s Kino Environmental Restoration Project flood-control basin, which discharges water into the Santa Cruz River to the west, said the 2015 report, which the Star obtained from the Arizona Department of Environmental Quality. The report was done by the Air Force Civil Engineer Center at Lackland Air Force Base in Texas.”

Read the full article by Tony Davis