New NIH Research Links Two Forever Chemicals to Higher Risk of Aggressive Breast Cancer
A significant new study from the US National Institutes of Health has identified an association between higher blood concentrations of two widely studied forever chemicals, PFOA and PFOS, and increased incidence of an aggressive form of breast cancer.
Published in the Journal of Clinical Oncology and announced by the NIH on 5 November 2026, the findings add to growing international research into the potential health impacts of per- and polyfluoroalkyl substances, commonly known as PFAS.
Although the research was conducted in the United States and Puerto Rico, its findings are relevant to the ongoing conversation about PFAS exposure, environmental contamination and drinking water quality in Australia.
What did the NIH researchers discover?
Researchers examined blood samples collected before breast cancer diagnosis, measuring 17 different PFAS compounds.
The strongest associations were identified for two long-studied chemicals: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS).
Women with higher blood concentrations of these compounds were more likely to develop estrogen receptor-negative (ER-negative) breast cancer. This subtype tends to be more aggressive than hormone-responsive breast cancers.
These percentages describe relative differences between study groups, not an individual's probability of developing breast cancer. The findings identify an association, rather than establishing causation.
Why these findings matter
The research highlights a potentially important relationship between exposure to certain persistent environmental chemicals and a breast cancer subtype with relatively few established risk factors.
The findings reinforce the importance of continued investigation into PFAS exposure and its possible long-term health implications.
What are PFAS and why are they called forever chemicals?
PFAS are a large family of manufactured chemicals that have been used for decades in industrial processes and everyday products.
Their resistance to heat, water, oil and staining has made them useful in applications such as non-stick coatings, water-resistant materials, certain food packaging and some firefighting foams.
The challenge is their persistence. Many PFAS compounds break down very slowly in the environment, allowing them to remain in soil, waterways and other environmental systems for extended periods.
Some PFAS can also accumulate in living organisms, making ongoing exposure an important area of environmental and public health research.
How can PFAS enter the water cycle?
PFAS can enter the environment through industrial activities, consumer products, waste disposal and contaminated runoff.
Once released, some compounds can move through soil, surface water and groundwater, potentially reaching water supplies, aquatic environments and food chains.
Importantly, drinking water is only one potential pathway of PFAS exposure. Food, consumer products and environmental contact may also contribute. The relative contribution of each pathway depends on local conditions and individual circumstances.
A US study, but why does it matter to Australia?
While the NIH findings come from research in the United States and Puerto Rico, PFOA and PFOS are not exclusively American environmental concerns.
Both compounds are recognised within Australia's drinking water guidance, and PFAS contamination has been identified in certain Australian environments.
The Australian National Health and Medical Research Council (NHMRC) completed a review of PFAS in drinking water in 2025, resulting in revised health-based guideline values.
Australia's updated PFAS drinking water guidelines
The NHMRC published the following health-based guideline values in June 2025:
| PFAS compound | Guideline value |
|---|---|
| PFOA | 200 ng/L |
| PFOS | 8 ng/L |
| PFHxS | 30 ng/L |
| PFBS | 1,000 ng/L |
ng/L means nanograms per litre. These are health-based guideline values, not measurements of PFAS in a particular household's water. Implementation is managed by state and territory authorities.
These guidelines reflect Australia's approach to managing potential long-term exposure.
PFAS concentrations vary by location and water source, so it is important not to assume that every drinking water supply contains elevated PFAS.
For more information, visit the NHMRC review of PFAS in Australian drinking water .
Can water filtration reduce PFAS?
With greater attention being placed on PFAS exposure, many Australians are asking whether filtration can help reduce particular chemicals in their drinking water.
The answer depends on the filtration technology, the individual PFAS compounds, the quality of incoming water, system design and maintenance.
Two established approaches used in PFAS treatment are activated carbon and reverse osmosis.
Activated carbon filtration
Activated carbon can adsorb certain PFAS compounds, helping reduce their concentrations in treated water.
Performance varies between compounds, carbon types, contact time and cartridge condition. Longer-chain PFAS are generally more readily adsorbed than some shorter-chain compounds.
Reverse osmosis
Reverse osmosis uses a semipermeable membrane to separate water from many dissolved substances.
Appropriately designed and maintained reverse osmosis systems can reduce a range of PFAS compounds, although specific performance should be supported by relevant test results.
Not all PFAS filtration claims are equal
PFAS is a family of chemicals, not one single contaminant. A result for one compound does not automatically demonstrate the same reduction for every PFAS chemical. Look for verified, compound-specific performance information.
Whole-house filtration or drinking water filtration?
At Pure Water Systems, we recognise that different households have different water sources, concerns and filtration requirements.
Two approaches worth understanding are Point of Entry and Point of Use filtration.
Point of Entry: Whole-house filtration
Whole-house filtration treats water as it enters the property, before distribution to household outlets.
Our Whole House Triple filtration range includes configurations with specialised carbon cartridges designed to target selected contaminants, including certain PFAS compounds.
The reduction achieved depends on cartridge configuration, water conditions, flow rate and maintenance.
Point of Use: Drinking water filtration
Point of Use filtration treats water at a dedicated location, commonly the kitchen tap, where water is used for drinking and cooking.
Reverse osmosis is one technology used for more extensive treatment of drinking water, including reduction of certain dissolved contaminants.
For renters and households that prefer a portable solution, selected benchtop filtration systems can provide drinking water filtration without permanent plumbing modifications.
A Point of Use system can also complement whole-house filtration when additional treatment is desired at the drinking water tap.
Explore water filtration designed for your home
Whether you own your home, rely on tank water or are renting, there are filtration options to suit different water sources, lifestyles and household requirements.
Whole House Triple - Town Water
A three-stage whole-house filtration system combining sediment and carbon filtration with a specialised PFAS-targeting cartridge.
Designed to treat incoming town water before distribution throughout the home.
EXPLORE TOWN WATER SYSTEMWhole House Triple - Tank Water
A whole-house filtration configuration designed for rainwater tank supplies.
Combines washable sediment filtration, carbon filtration and a specialised cartridge targeting selected PFAS compounds.
EXPLORE TANK WATER SYSTEMReverse Osmosis (RO) Filtration
Reverse osmosis uses membrane technology to reduce a broad range of dissolved contaminants in drinking water.
Explore our range of reverse osmosis filtration systems, including options with remineralisation.
RO technology can reduce selected PFAS compounds. Specific performance depends on the system and testing.
EXPLORE REVERSE OSMOSISBenchtop Water Filtration
Renting or looking for a filtration solution without permanent plumbing modifications?
Our portable benchtop water filters offer convenient drinking water filtration without the need for an under-sink installation.
Selected benchtop systems feature our HTO+ cartridge, designed to target a range of contaminants, including PFAS compounds PFOA and PFOS, the two forever chemicals highlighted in the NIH research.
Explore our Luxe Collection and Quick Change benchtop options for a practical filtration solution that can move with you.
EXPLORE BENCHTOP FILTERSFiltration performance varies by system, cartridge configuration, water conditions and maintenance. The HTO+ cartridge is designed to target selected PFAS compounds, including PFOA and PFOS. Specific reduction percentages should be supported by product performance testing.
What can Australian households do?
Understanding your water source is a useful starting point.
For households connected to town water, local water suppliers and relevant government authorities can provide information about monitoring and drinking water quality.
For private water sources, including bore water and rainwater tanks, property owners may need to arrange appropriate testing if contamination is suspected.
When comparing filtration systems, consider the contaminants you want to target, the test evidence available, the system's suitability for your water source and its ongoing maintenance requirements.
Frequently asked questions about PFAS
Does the NIH study prove PFAS causes breast cancer?
The study identified an association between higher blood levels of PFOA and PFOS and increased incidence of ER-negative breast cancer. It did not establish a causal relationship. The findings support further investigation into potential health effects of these compounds.
Does this mean Australian tap water is unsafe?
No conclusion about the safety of a particular Australian water supply can be drawn from this US study. PFAS concentrations vary between locations. Local monitoring information provides a more relevant picture.
Can PFAS be removed from drinking water?
Certain treatment technologies, including activated carbon and reverse osmosis, can reduce specific PFAS compounds. Results vary, and not every system is tested or designed for the same contaminants.
Does the HTO+ cartridge target PFOA and PFOS?
The Pure Water Systems HTO+ cartridge is designed to target selected PFAS compounds, including PFOA and PFOS. Specific reduction percentages should be confirmed against the relevant product performance data.
Is whole-house filtration enough?
It depends on the system, its cartridges, the water source and the compounds of concern. Whole-house filtration and dedicated drinking water filtration serve different purposes and can be used together.
How do I know whether my water contains PFAS?
For town water, check information provided by your water supplier or relevant authority. For private supplies, appropriately accredited laboratory testing may be needed.
Why this research deserves attention
The NIH announcement of 5 November 2026 adds important evidence to the international discussion about PFAS and human health.
Its findings highlight an association between two persistent chemicals and an aggressive breast cancer subtype, reinforcing the need for continued research into environmental exposure.
For Australians, the wider message is the value of understanding where PFAS may be found, how exposure can occur and what reliable water-quality information can tell us.
At Pure Water Systems, we believe in helping households make informed water filtration decisions through clear education and transparent product performance information.
Understand your water. Explore your options.
Every water source is different. Explore filtration solutions suited to your household's water source and concerns.
EXPLORE WATER FILTRATIONSources and further reading
1. US National Institutes of Health
Two 'forever chemicals' associated
with higher risk of aggressive
breast cancer in NIH analysis.
Published 5 November 2026.
Read the NIH announcement
2. Journal of Clinical Oncology
Chang CJ, Pullella K, Keil AP, et al.
Per- and Polyfluoroalkyl Substance
Exposure and Breast Cancer Incidence
in the Sister Study.
View the published study
3. National Health and Medical Research Council
NHMRC Review of PFAS in
Australian drinking water.
Published 25 June 2025.
Read the Australian PFAS guidance
Editorial note: This article provides general information about published research and water filtration. The NIH study did not evaluate Pure Water Systems products or whether filtration changes cancer outcomes. Product-specific contaminant reduction claims should be assessed against relevant testing documentation.