"PFAS are well-established environmental toxicants and were found at high levels in AFFF [Aqueous Film Forming Foam]-impacted Australian communities such as Upper Blue Mountains and Williamstown in NSW and Oakey, Queensland. Although this group consists of multiple sub-groups with varying toxicity, PFOS, PFOA, and PFHxS has been the most frequently detected in AFFF impacted drinking water.

This new Blomberg et al., (2026) study utilised a Swedish cohort of 11,488 children, which were divided into four groups of very high, high, intermediate and background levels of prenatal PFAS exposure based on maternal address history to understand the relationship between PFAS exposure and the incidence of either asthma or wheeze.

The novelty of the results is the close association found between the very high prenatal PFAS exposure and asthma. However, the median PFAS concentration for this ‘very high’ group (PFOS + PFOA + PFHXs = 394.67 ng/mL) is at least 10 times higher than those reported in Australian AFFF impacted communities.

For example, 20.98 ng/ml PFAS was detected in the serum of a resident from blue mountains*, while the Australian mean serum PFAS concentration was recently reported to be 1.67 ng/ml**.

Therefore, the results from Blomberg et al., (2026) may not be directly relevant to the majority of Australians, albeit, it adds an important piece of evidence of PFAS’s immunotoxicity at very high exposure levels.

*https://www.abc.net.au/news/2025-02-13/pfas-blue-mountains-blood-testing/104917304

**https://theconversation.com/new-australian-data-shows-most-of-us-have-pfas-in-our-blood-how-worried-should-we-be-257648"

"This is an interesting study, and it is not the first to suggest possible health effects from the exceedingly high PFAS exposure in this specific Swedish town. The story of Ronneby, which has some of the worst PFAS contamination anywhere in the world, almost reads like a new literary genre - Chemical Nordic Noir. However, there are some key points to keep in mind with this particular study.

Firstly, the children's exposure to PFAS was not directly measured, but estimated based on their addresses and how long they lived there. We don’t know how much PFAS they were actually exposed to.

Secondly, what has been reported is an association, not a direct relationship. It does not prove causation. One might find a statistical association between asthma and any number of factors, but that does not automatically prove that one caused the other. It just gives you an idea of what might be worth exploring further.

If PFAS did cause asthma, we might expect to see a dose-dependent effect - e.g., the more PFAS the child was exposed to, the higher their likelihood of developing asthma, but this was not observed. The alleged effect was not seen except in those in the very highest PFAS exposure group, who were exposed to exceedingly high PFAS concentrations. Previous studies of possible links between PFAS and asthma also did not find a clear link.

Finally, while the results suggest a possible health effect of certain types of PFAS at very, very high concentrations, they don’t prove anything directly. There are very few, if any, communities anywhere that have been exposed to a concentration of PFAS anywhere near that associated with asthma in this paper.

Thus, even if everything in this paper is correct, the results are likely to apply only to this specific town - so, I would say Australians do not have to worry about PFAS giving us asthma."

"This Swedish study is the latest instalment of research results that suggest that the fluorinated chemicals (PFAS) to which we are all exposed, in one way or another, may be having harmful effects. Many other epidemiological (population-based) studies have shown correlations between exposure and a range of health effects. But taking the next step, establishing cause and effect beyond just correlation, is not really possible by population studies. Much more research would be needed for that, such as establishing the exact mechanism by which harm is caused. The authors acknowledge this, calling for repetition of their work, but also claiming that there is already a biologically plausible link between between exposure and the effects they have studied. That is, there is at least some notion of the likely biological mechanism.

Because their study involved large number of children, over 11,000, extended over more than a decade, and was based in a region where drinking water was comparatively more contaminated by PFAS so inadvertent doses were higher than in other studies,  the authors feel that their results are among the more significant.

The exposure of fetuses to PFAS ingested with drinking water by pregnant mothers correlated well with the childhood incidence of respiratory symptoms, asthma and wheezing. The exposure was due to contamination of drinking water by industrial waste from film-forming industry. Among the contaminants detected in the study was the original 'villain' in the PFAS saga - the first one to be banned under the Stockholm Convention on Persistent Organic Pollutants (POPs) - perfluorooctane sulfonic acid (PFOS). The careful process of deciding which pollutants to ban takes a few years, but once banning of PFOS under the Convention seemed likely, manufacturers introduced fluorinated substances that were not-PFOS but were chemically similar, such as perfluorohexane sulfonic acid (PFHxS) and perfluooctanoic acid (PFOA). Both of these 'lookalikes' now come under the Stockholm Convention, too, and all three were present in the drinking water available to the mothers in this study."

"The adverse health effects of PFAS chemicals remain uncertain, particularly at the low levels of exposure that occur in the general community. The current study found that exposure to PFAS during pregnancy increased the risk of developing asthma in childhood. However, the risk was only observed in the study’s ‘very high’ exposure group. There was no increased risk in children born to mothers in either the ‘high’ or ‘intermediate’ exposure groups.

The average potential PFAS concentrations in mothers in the ‘very high’ exposure group were many times greater than what has been found in the general population, and even much higher than what was found in high exposure risk groups in Australia, i.e. around airforce bases at Oakey, Williamtown and Katherine. Even the ‘high’ and ‘intermediate’ groups had much greater average PFAS concentrations than those high exposure risk groups in Australia.

The study had limitations, not least that exposure was based on residential address in the years prior to, and the nine months of, pregnancy, rather than determined from personal blood samples. However, the study adds evidence of potential adverse health effects at high exposure to PFAS chemicals. The effects of low-level exposure, if any, are still unclear."