Month: June 2026

I’ve been asked what kind of data exists for other comparable locations. This is my starter for ten…

A substantial body of data now links PFAS contamination with military airfields, civil airports, aircraft rescue and firefighting stations, and fire-training grounds. These settings provide strong comparators for former RAF Upper Heyford because they share several features: long-term storage and use of aqueous film-forming foam, repeated training exercises, fuel-fire risks, drainage into nearby streams, and seepage through soil into groundwater.

Direct comparison requires care. Studies may report individual compounds, such as PFOS or PFOA, or a sum of several PFAS. They may also test untreated groundwater, surface water, drinking water, soil, sediment, or laboratory leachate. Concentrations in water are often given as nanograms per litre, or ng/L. One microgram per litre, or µg/L, equals 1,000 ng/L.

Military airports and air-force bases

One of the best documented studies concerns a former Swedish military airport. PFOS and PFOA occurred throughout soil around former firefighting areas. Soil concentrations ranged from 2.18 to 8,520 ng/g for PFOS and below 0.12 to 287 ng/g for PFOA. The contamination had spread from the fire-training area into groundwater, lakes and fish. The authors concluded that the affected aquifer would need continuing treatment because contaminated water continued to move through it at about 7,500 cubic metres per day (Filipovic et al., 2015).

At a military fire-training site on Cape Cod in the United States, researchers combined several decades of groundwater records with soil data. They found that a large PFAS mass remained in the unsaturated soil above the water table. This soil acts as a long-term reservoir, releasing PFAS into groundwater through rainfall, leaching and the gradual conversion of precursor chemicals. Their model suggested that groundwater pollution could continue for more than a century without effective source control (Ruyle et al., 2023).

At Peterson Air Force Base in Colorado, groundwater near a former fire-training area contained combined PFAS concentrations reported at approximately 3.24 µg/L and 15 µg/L. These figures equal 3,240 and 15,000 ng/L. The affected groundwater was moving towards the base boundary, where local water supplies depended in part on wells (U.S. Environmental Protection Agency, 2024).

At Ellsworth Air Force Base in South Dakota, PFAS have migrated beyond the base and entered private wells. The estimated affected surface-water and groundwater corridor extends about 25 miles along Boxelder Creek towards the Cheyenne River. This case shows that an airbase release may create a regional contamination pathway rather than a small, fixed patch beneath the original fire-training area (U.S. Environmental Protection Agency, 2023).

Australian military data offer further useful comparisons. At RAAF Base Pearce, the fire-training area was identified as the largest PFAS source, with more than 200 kg of PFAS estimated in contaminated soil. PFAS moved from the base through drains and streams before entering groundwater beyond the perimeter. At RAAF Base Richmond, investigators estimated that groundwater carried less than 10% of the PFAS leaving the base, while surface water carried most of the pollution. These cases show why monitoring only boreholes may miss a major part of the total PFAS discharge (Australian Department of Defence, n.d.-a, n.d.-b).

Civil airports and fire-training facilities

Civil airports show concentration ranges from several hundred ng/L to many millions of ng/L. Canadian studies summarised in a recent groundwater review found PFOA concentrations of 620–4,100 ng/L at a closed fire-training site in Newfoundland. At an active Ontario airport site, PFOA reached 36,000–85,000 ng/L, while PFOS ranged from 840 to 1,500 ng/L. Across four Canadian airport fire-training areas, the highest recorded total PFAS concentration was about 10,800,000 ng/L, or 10,800 µg/L, in groundwater within an active source zone.

At a Norwegian airport firefighting site, PFOS concentrations in soil reached 13,400 ng/g. Laboratory tests on contaminated soil produced leachate containing up to 550 µg/L PFOS, equal to 550,000 ng/L, and 22 µg/L PFHxS. These were laboratory leaching results rather than concentrations measured in a drinking-water supply, but they show the capacity of contaminated fire-training soil to release very high PFAS concentrations into water (Bräunig et al., 2019).

A separate Norwegian fire-training study examined a site 15 years after the use of PFOS-based foam had stopped. PFOS still made up about 96% of measured soil PFAS, with concentrations reaching 6,500 µg/kg. The study documented continued movement from contaminated soil towards groundwater, despite the long period since PFOS foam use ended (Høisæter et al., 2019).

Indicative comparison

Setting	Medium	Reported PFAS level or scale
Swedish former military airport	Soil	PFOS up to 8,520 ng/g
Peterson Air Force Base	Groundwater	Combined concentrations up to about 15,000 ng/L
Canadian active airport training site	Groundwater	PFOA 36,000–85,000 ng/L
Canadian airport source zone	Groundwater	Total PFAS up to 10,800,000 ng/L
Norwegian airport soil leachate	Laboratory leachate	PFOS up to 550,000 ng/L
RAAF Base Pearce	Soil mass	More than 200 kg PFAS in the fire-training source area
Ellsworth Air Force Base	Water plume	About 25 miles of affected corridor

These results suggest that very high readings near Gallos Brook or the former Upper Heyford fire-training ground would not be without precedent. Concentrations in the tens of thousands of ng/L lie within the range reported at heavily contaminated airfields. Readings in the millions of ng/L occur at some source zones where foam was repeatedly discharged.

The closest comparison depends on where the Upper Heyford sample was taken. A sample collected from water draining directly from the fire-training site should be compared with source-zone groundwater, leachate, drains or runoff. It should not be compared without qualification with treated tap water. A brook sample taken further downstream may reflect dilution, sediment exchange, seasonal rainfall and continuing inputs from contaminated soil.

The international evidence also points to four issues that merit investigation at Upper Heyford. First, the former training soil may remain a continuing source decades after the last foam use. Second, drains and surface water may carry more PFAS off site than deep groundwater. Third, contamination may extend beyond the airfield boundary and follow brooks, ditches and shallow geological layers. Fourth, testing only PFOS and PFOA may understate the total burden because modern laboratory panels can detect a much wider set of PFAS and precursor compounds. The Environment Agency recognises airports and firefighting training sites as major PFAS source types, but public UK site-level concentration data remain much less complete than equivalent US and Australian records.

References

Australian Department of Defence. (n.d.-a). RAAF Base Pearce: PFAS management. https://www.defence.gov.au/about/locations-property/pfas/pfas-management-sites/raaf-base-pearce-bullsbrook

Australian Department of Defence. (n.d.-b). RAAF Base Richmond: PFAS management. https://www.defence.gov.au/about/locations-property/pfas/pfas-management-sites/raaf-base-richmond

Bräunig, J., Baduel, C., Heffernan, A., Rotander, A., Donaldson, E., & Mueller, J. F. (2019). Leaching and bioavailability of selected perfluoroalkyl acids from soil contaminated by firefighting activities. Science of the Total Environment, 646, 471–479. https://doi.org/10.1016/j.scitotenv.2018.07.231

Environment Agency. (2021). Poly- and perfluoroalkyl substances: Sources, pathways and environmental data. Department for Environment, Food and Rural Affairs.

Filipovic, M., Woldegiorgis, A., Norström, K., Bibi, M., Lindberg, M., & Österås, A.-H. (2015). Historical usage of aqueous film forming foam: A case study of the widespread distribution of perfluoroalkyl acids from a military airport to groundwater, lakes, soils and fish. Chemosphere, 129, 39–45. https://doi.org/10.1016/j.chemosphere.2014.09.005

Høisæter, Å., Pfaff, A., & Breedveld, G. D. (2019). Leaching and transport of PFAS from aqueous film-forming foam in the unsaturated soil at a firefighting training facility under cold climatic conditions. Journal of Contaminant Hydrology, 222, 112–122. https://doi.org/10.1016/j.jconhyd.2019.02.010

Ruyle, B. J., Thackray, C. P., Butt, C. M., LeBlanc, D. R., Tokranov, A. K., Vecitis, C. D., & Sunderland, E. M. (2023). Centurial persistence of forever chemicals at military fire training sites. Environmental Science & Technology, 57(21), 8096–8106. https://doi.org/10.1021/acs.est.3c00675

U.S. Environmental Protection Agency. (2023). Ellsworth Air Force Base Superfund site community profile.

U.S. Environmental Protection Agency. (2024). Statement of basis: Peterson Air Force Base municipal separate storm sewer system permit.

(c) 2026 Graham Wilson. This work is licensed under CC BY-NC 4.0. To view a copy of this license, visit creativecommons.org

In an area known to have exceptionally high levels of PFAS in local groundwater (43000 times the recommended safe-levels), and where the mains water supply is fed from aquifers immediately beneath an air-force base fire training area, does it make sense to switch to bottled water as a short-term precaution?

Obviously, this is a personal choice. Do you want to wait until better information is available? Do you consider that long-term health risks are low in your priorities (as many smokers do)? Are you someone who is particularly lifestyle aware, who makes other food and drink related choices for health reasons?

However, for most of us, the simple answer is yes. As a short-term precaution, switching to bottled water for drinking, tea, coffee, cooking water, and tooth-brushing makes sense while you seek hard evidence about the treated mains supply. So far, there is no proof that the tap water is unsafe, but the facts that we have about our supply do create a clear source-pathway-receptor concern: a known PFAS source, extreme groundwater results, an aquifer pathway, and a drinking-water receptor.

The key point is that groundwater contamination is not the same as tap-water contamination. Mains water may be blended, treated, drawn from a different borehole, or monitored before supply. So far, however, Thames Water have been very limited in their response to questions.

The Drinking Water Inspectorate (DWI) says water firms must ensure water is wholesome, but England and Wales still lack a statutory PFAS limit. The DWI instead uses a tiered guidance system, now focused on the summed level of 48 PFAS, with 100 ng/L treated as a key action level. The Royal Society of Chemistry has argued for tighter controls, including 10 ng/L for any single PFAS and 100 ng/L for total PFAS. (Drinking Water Inspectorate)

The level measured in Gallos Brook recently – 43,000 times the recommended safe level – is so high that it justifies caution even before tap-water proof exists.

In case, anyone has missed the news in the last few months, air-force fire training areas are a well-known source of PFAS, due to historic use of aqueous film-forming foams. PFAS are persistent, mobile in water, and linked in the evidence base to harms that include effects on immunity, cholesterol, liver function, thyroid function, pregnancy outcomes, and some cancers. The US EPA now sets legally enforceable drinking-water limits of 4 ng/L for PFOA and PFOS, with 10 ng/L limits for several other PFAS. (US EPA)

Bottled water is not a perfect answer. PFAS have been found in some bottled waters, and bottled water brings cost, plastic waste, and microplastic concerns. A 2024 study reported PFAS in both tap and bottled water samples from the UK and China, with PFOA and PFOS detected in over 99% of bottled-water samples from 15 countries (University of Birmingham). Even so, bottled water from a source outside the suspect aquifer is a rational temporary measure when local groundwater contamination is extreme.

For the short term, using bottled water for all water that is swallowed, especially for children, pregnant people, and anyone with immune, thyroid, kidney, liver, or cancer risk concerns. Don’t worry much about showering or hand-washing unless official advice changes, because the main concern for PFAS in water is ingestion.

Boiling water does not remove PFAS – in fact, the opposite as it can concentrate them.

Is any bottled water likely to be safer, and is there any difference between spring water, mineral water, branded, and own label water from supermarkets?

Yes, some bottled water is likely to be safer than your local tap water as a short-term step, but no ordinary bottled-water label proves that it is PFAS-free. The safest choice would be water with a recent batch or source test showing low or non-detect PFAS. In normal shop terms, the next best rule is to choose water bottled from a named source outside the suspect catchment, rather than water with vague branding.

The legal labels matter, but not as much as the source. Natural mineral water has the tightest identity. It must come from an officially recognised underground source, keep its “original purity”, have a stable composition, and use only a small set of permitted treatments. The producer must gather safety and stability data, and Defra lists recognised UK natural mineral waters by source and place of exploitation. (GOV.UK) This makes natural mineral water more traceable, though it does not mean zero PFAS.

Spring water also comes from an underground source, but the regulatory status is less distinctive than natural mineral water. It may be a sound choice if the label names the spring or borehole and the source sits far from known PFAS sites. Bottled drinking water is a broader class. It may be treated water from various sources. That could be safer if it has been treated by reverse osmosis or high-grade activated carbon, but the label may not tell you enough.

Branded water is not always safer than supermarket own-label water. Some own-label waters come from recognised sources and are bottled by the same large suppliers that bottle branded products. For example, the current UK list includes recognised natural mineral waters such as Ashbeck, Aqua Pura, Celtic Spring, Radnor Hills, and Waitrose Welsh Spring, each with its named place of exploitation. (GOV.UK) The real test is not price or brand; it is source, treatment, and PFAS data.

There is also a limit to what bottled water can solve. A 2024 study found PFAS in both tap and bottled water, with PFOA and PFOS detected in over 99% of bottled-water samples sourced from 15 countries. It also found wide variation across samples. (University of Birmingham) This means bottled water may reduce a local high-risk exposure, but it should not be treated as pure water.

For your short-term purpose, I would choose in this order: natural mineral water from a clearly named distant source, then spring water from a clearly named distant source, then treated bottled drinking water only if the treatment is stated. I would not rely on “British”, “pure”, “mountain”, “still”, or “premium” as safety terms. I would also avoid local or regional bottled water if its source lies in the same broad aquifer system as the air-force base.

For the options we discussed earlier, Celtic Spring and Radnor Hills have named Welsh sources on the recognised natural mineral water list, which gives them traceability. Highland Spring has stronger packaging claims, but for PFAS risk the more relevant question is whether it publishes current source-water PFAS tests. Until such data are in hand, a cheap named-source natural mineral water is a reasonable short-term precaution.

Does the packaging make a difference? Water comes in glass bottles, cans, plastic lined boxes, and in a few cases in a carton.

Yes, packaging can make a difference, but probably less than the source water itself when the chief concern is PFAS. The best short-term choice would still be a named-source water from outside the suspect aquifer, with the least complex packaging.

Glass is usually the most inert main container. It does not shed plastic from the body of the bottle, and it has low chemical migration compared with many other materials. The main caveat, though, is the closure. A 2025 French study found that some drinks in glass bottles had higher microplastic counts than plastic bottles or cans, probably due to polyester-based paint on metal caps. The glass itself was not the source. (anses.hal.science)

PET plastic bottles are food-grade and widely used, but bottled water in plastic tends to carry more microplastic and nanoplastic concern than tap water in many studies. A review of 21 studies found microplastics in both tap and bottled water, with higher levels in bottled water. (PMC) This does not mean PET water is acutely unsafe. It means PET is a less ideal long-term default, especially if bottles are stored warm, reused, crushed, or left in sunlight.

Cans are not bare metal inside. They almost always have a polymer lining to stop corrosion and taint. That lining may reduce metal leaching, but it adds another food-contact layer. It is not an obvious gain over glass or PET for water, unless the firm publishes good test data. The same point applies to boxed water and cartons. They look paper-based, but they usually contain layers of board, plastic, and sometimes aluminium. They are complex packs, and their safety depends on the liner and sealant, not on the word “carton”.

For PFAS, the position is more awkward. UK food-contact material law requires packaging to be safe for food use, but campaign and policy sources note that UK rules still do not set broad limits for most PFAS in food-contact materials. (Food Standards Agency) The EU’s new packaging rules move further by restricting PFAS in food-contact packaging above set thresholds, but that does not yet give you a simple UK shop-shelf guarantee. (Environment)

A pragmatic ranking would be: glass bottle with a plain screw cap, then large PET bottle from a named distant source, then can, then carton or boxed water. For short-term PFAS caution, you can buy large 5L PET or glass from a traceable source rather than small bottles, cans, or cartons. Large bottles reduce the amount of packaging contact per litre and reduce waste.

Have we switched?

Yes. As someone who believes very strongly in the importance of evidence, as a short-term solution, we have switched to spring-water from Scotland in 10l bags within a cardboard box.

After a lot of searching online, we settled on these from Purely Scottish. We chose them because the bags are double-lined and made from a plant-based plastic substitute. This means that they can be separated and used to line our silver food-waste bin, from which they go off to be industrial biodegraded. They are therefore one of the better options for the environment.

Purely Scottish water works out at about 68p per litre. If you want to switch but prefer a cheaper, plastic container, option then the best on the market right now is Celtic Spring in 5l boxes from Iceland at 28p per litre. Waitrose Own Label in 5l boxes is 34p per litre. Highland Spring, which is very popular, is £1.40 per litre.

References

Chaïb, I., et al. (2025). Microplastic contaminations in a set of beverages sold in France. Journal of Food Composition and Analysis. (anses.hal.science)

Department for Environment, Food and Rural Affairs. (2026). UK natural mineral waters recognised in the UK: List of products. GOV.UK. (GOV.UK)

Department for Environment, Food and Rural Affairs. (2020). Natural mineral water: Rules for local authorities. GOV.UK. (GOV.UK)

Drinking Water Inspectorate. (2026). PFAS and forever chemicals. https://www.dwi.gov.uk/pfas-and-forever-chemicals/

European Commission. (2026). Packaging waste. (Environment)

Food Standards Agency. (2018). Food contact materials regulations. (Food Standards Agency)

Gambino, I., et al. (2022). Occurrence of microplastics in tap and bottled water. International Journal of Environmental Research and Public Health. (PMC)

Royal Society of Chemistry. (2023). Cleaning up UK drinking water. https://www.rsc.org/policy-and-campaigning/sustainability/cleaning-up-uk-drinking-water

Royal Society of Chemistry. (2023). RSC challenges UK Government to reduce PFAS levels in British water. https://www.rsc.org/news/2023/october/rsc-challenges-uk-government-to-reduce-pfas-levels-in-british-water-as-research-highlights-serious-health-risks-posed-by-%E2%80%98forever-chemicals%E2%80%99

United States Environmental Protection Agency. (2024). Final PFAS national primary drinking water regulation. https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas

University of Birmingham. (2024). Forever chemicals found in bottled and tap water from around the world. (University of Birmingham)

(c) 2026 Graham Wilson. This work is licensed under CC BY-NC 4.0. To view a copy of this license, visit creativecommons.org