Per- and polyfluoroalkyl substances (PFAS)

Per- and polyfluoroalkyl substances (PFAS) are a class of manufactured chemicals with over 15,000 identified different compounds (OECD 2018, 2021; US EPA 2022). Some PFAS are very effective at resisting heat, stains, grease, and water giving them a wide range of useful applications across a range of industries (OECD 2021; UNEP 2024; PFAS Taskforce n.d.).

PFAS are characterised by their chemical structure which usually consists of multiple fluorine atoms attached to a carbon chain, although different definitions are used worldwide (Buck et al. 2011; Hammel et al. 2022). The OECD defines them as fluorinated substances containing “at least one fully fluorinated methyl or methylene carbon atom” (OECD 2021). Perfluoroalkyl substances have a fully fluorinated carbon chain, whereas polyfluoroalkyl substances may have hydrogen or oxygen atoms attached to at least one carbon in the chain.

The properties that make PFAS useful in industrial applications and particularly in fire-fighting foams, also make them problematic in the environment. Many PFAS can travel long distances from where they are first used due to their mobility in water. They are also largely inert and difficult to break down so they can last a long time in the environment (PFAS Taskforce n.d.). PFAS with long elimination half-lives have the capacity to bioaccumulate in human systems. Human exposure to PFAS in the household or occupational settings was common due to their widespread commercial and industrial uses, resulting in most people in the general Australian population having PFAS in their blood (DHAC 2024; HEPA 2025).

The understanding of the human health effects of long-term PFAS exposure is still developing, but global concern about the persistence and mobility of these chemicals in the environment have prompted many countries to reduce or phase out their use (UNEP 2024). The Australian Government has worked since 2002 to reduce the use of certain PFAS in a range of industries (PFAS Taskforce n.d.). For the general population, PFAS levels in the blood (serum PFAS) are expected to decline over time due to the declining use in household items.

Laboratory test information, including analysis methods and machines used to measure PFAS, is available from the Downloads page.

PFAS results were obtained for persons aged 12 years and over who provided a blood sample. Fasting was not required for this test.

A blood sample was collected from participants and selected PFAS levels were measured using mass-labelled isotope dilutions and ultrafiltration analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at the Sullivan Nicolaides Pathology laboratory.

Each PFAS test measures the level of the selected PFAS in the blood serum at the time of sample collection. PFAS levels are expressed in nanograms per millilitre (ng/mL).
 

There is no consensus of epidemiological cut-off reference values for measuring PFAS serum levels (NCEPH 2020; VDH 2018). Therefore, no cut-off points have been defined in the NHMS.

The limit of quantification (LOQ) is the lowest level of PFAS that can be accurately measured (quantified) and varies depending on the PFAS being analysed. Test results greater than or equal to the LOQ were considered as having positive PFAS detection, whilst results below the LOQ were considered a non-detect. A non-detect result does not mean that a person has no PFAS in their blood, just that the level was too low to be detected by the test methodology. It is expected that all persons have had some exposure to PFAS.

To account for non-detects in the calculation of summary statistics, PFAS results below the LOQ were assigned a numerical value (imputed) equal to the LOQ divided by the square root of two (LOQ/√2) (Smurthwaite et al. 2021).

The following table outlines the LOQ and imputed values of non-detect results for each type of PFAS.
 

PFAS levels have a positively skewed distribution in the population. To aid statistical analysis, PFAS values were transformed into an approximate normal distribution by taking the natural logarithm of the values. Weighted means, quantiles, and associated 95% confidence intervals were estimated from the log-transformed data. Statistical significance testing was also performed on the log-transformed data when presenting results.

The exponential of the mean value of the log-transformed data is called the geometric mean and was calculated for PFAS with at least 60% detection for a given population. The geometric mean is a measure of central tendency which is less sensitive to the effect of large values compared to an arithmetic mean. Geometric means are often used for analysis of environmental contaminants. The arithmetic mean of the non-transformed data was also calculated.

Points to be considered when interpreting data for this topic include the following:

• Blood levels of PFAS are not predictive of health problems in individuals. The understanding of the impact of PFAS on human health is ongoing and there are no current ‘normal’ or ‘abnormal’ ranges for PFAS levels in the blood.
• PFAS blood tests do not measure levels precisely. Tests taken from the same person at the same time may show variability due to the test methodology.
• It is not recommended to sum individual PFAS types to produce an overall level of serum PFAS. The NHMS tested for 11 commonly measured and understood PFAS, and these may not reflect the total amount of PFAS in an individual. In addition, results for PFAS levels below the LOQ are not available in the DataLab microdata products, therefore summing multiple PFAS types using imputed values would only be an approximation of their true level.

This is the first time the ABS has collected information on PFAS. As such, analysis over time is not possible.

PFAS data has been collected in other non-ABS studies. However, caution must be taken when interpreting results due to the differences in scope, year of collection, assay and the instrument used, imputation of ‘not-detected’ results, and any thresholds applied in the final analysis.
 

Australian Government PFAS Taskforce (PFAS Taskforce) (n.d.), What are PFAS?, About PFAS, PFAS Taskforce, accessed 17/04/2025.

Buck RC, Franklin J, Berger U, Conder JM, Cousins IT, de Voogt P, Jensen AA, Kannan K, Mabury SA, van Leeuwen SPJ (2011), Perfluoroalkyl and polyfluoroalkyl substances in the environment: terminology, classification, and origins, Integrated Environmental Assessment and Management, 7(4):513-541, accessed 17/04/2025.

Department of Health and Aged Care (DHAC) (2024), Per-and-Polyfluoroalkyl substances (PFAS), DHAC website, accessed 17/04/2025.

Hammel E, Webster TF, Gurney R, Heiger-Bernays W (2022), Implications of PFAS definitions using fluorinated pharmaceuticals, iScience, 25(4):104020, accessed 17/04/2025.

Heads of EPA Australia and New Zealand (HEPA) (2025), PFAS National Environmental Management Plan Version 3.0, HEPA, accessed 17/04/2025.

National Centre for Epidemiology and Population Health (NCEPH) (2020), Pre-test consultation advice for GPs, PFAS Health Study, NCEPH, accessed 17/04/2025.

Organisation for Economic Co-operation and Development (OECD) (2018), Summary report on the new comprehensive global database of Per- and Polyfluoroalkyl Substances (PFASs), OECD Series on Risk Management of Chemicals, OECD, accessed 17/04/2025.

Organisation for Economic Co-operation and Development (OECD) (2021), Reconciling Terminology of the Universe of Per- and Polyfluoroalkyl Substances, OECD Series on Risk Management of Chemicals, OECD, accessed 17/04/2025.

Smurthwaite K, Lazarevic N, Bräunig J, Mueller J, Nilsson S, D’Este C, Lucas R, Armstrong A, Lal A, Trevenar S, Law HD, Gad I, Hosking R, Joshy A, Clements A, Lane J, Batterham P, Banwell C, Miller A, Randall D, Korda R, Kirk M (2021), PFAS Health Study Component two: Blood serum study of PFAS exposure, related risk factors and biochemical markers of health, PFAS Health Study, National Centre for Epidemiology and Population Health, accessed 17/04/2025.

United Nations Environment Programme (UNEP) (2024), Per- and Polyfluoroalkyl Substances (PFASs), UNEP website, accessed 17/04/2025.

United States Environmental Protection Agency (US EPA) (2022), CompTox Chemical Dashboard – PFAS Structure Lists, US EPA, accessed 17/04/2025.

Victorian Government Department of Health (VDH) (2018), Advice for General Practitioners - Voluntary blood testing for per- and poly- fluoroalkyl substances (PFAS), VDH, accessed 17/04/2025.