Annual progress reports

Systematic multidisciplinary approach to define impacts, molecular mechanisms, and ways to treat PFAS exposure (1185002)

  • Professor Graham Neely (Chief Investigator A)
  • University of Sydney
  • Budget: $2,539,080
  • Funding period: 2020 to 2025

Project Synopsis

A globally unique team will investigate the impacts of PFAS exposure on humans, from the population down to the molecular level. First, we will perform a series of innovative “living” analysis on all published data to identify how PFAS exposure impacts human health, which we will then validate using stem cells differentiated into various human tissues. In parallel, we will use new genome editing technologies to define the precise mechanisms of action for how PFAS exert their toxic effects on human samples, information which will inform on disease mechanisms and ways to treat exposure. Finally, since PFAS exposure can lead to long lasting contamination, we will functionally identify safe strategies to remove PFAS from living animals, information that will lay the ground work for helping at risk populations dealing with significant PFAS exposures. Our study will be performed in coordination with relevant consumers and stakeholders (Aboriginal community council, local and state government, professional organisations, media). We have already engaged with these entities and have established a framework for continued engagement over the course of this study. Most importantly, guided by our consumers specific interests we have defined the core biological mechanism of action for how one PFAS compound acts on human cells, and importantly have identified a new FDA-approved compound that can mitigate the effects of PFAS exposure in vivo and will continue these efforts in this study.

Progress report 30 April 2023

Since the previous report, a whole genome screen for PFAS (PFOS) toxicity using human liver cells has been completed, and validating of the results is underway. A 2000 molecule FDA-approved drug screen has been completed which identified a drug that is safe for human use and can suppress PFAS toxicity. When given prophylactically, this drug can basically provide almost complete protection. Currently its effects on other PFASs’ is being evaluated as well as the tracking of PFOS in vivo to see if this compound can liberate PFOS and help remove it from the animal, or just protect from the effects, either is valuable.

An additional PFAS meta-analysis (i.e. literature analysis) was completed and a new manuscript is being submitted for publication.

Overall, the goal has been to clarify the current understanding of how PFAS impacts humans and animals, identify the molecular pathways PFAS use to harm human physiology and identify drugs that can block PFAS toxicity. Success has been achieved on all fronts. The research team is working on finalising these data and publishing the results in order to better help protect people at risk of harmful PFAS exposure.

 

Per- and poly-fluoroalkyl substance (PFAS) Exposure and Health Outcomes in Firefighters (1182022)

  • Associate Professor Deborah Glass (Chief Investigator A)
  • Monash University
  • Budget: $566,906.10
  • Funding period: 2020 to 2024

Project Synopsis

Firefighting foams containing PFAS have been used in Australia since 1970 but have been phased out over the last 10 years. Firefighters are likely to be the highest exposed occupation in Australia. PFAS are very persistent and can remain in the human body and the environment for many years.

We have an existing national cohort, of over 230,000 firefighters assembled in 2011 for a cancer and mortality study. The cohort is made up of 17,394 male and 641 female full-time firefighters, 12,663 male and 1,041 female part-time firefighters and 163,159 male and 37,973 female volunteer firefighters. It includes individualised data on the agency, jobs held and the incidents attended. An update of the mortality and cancer incidence of this cohort would be a cost-effective way of addressing the Expert Health Panel priority related to the long term health of firefighters.

Subgroups of firefighters exposed to higher levels of PFAS or at higher frequency would be identified by:

  • consultations with fire agencies, trades unions and volunteer associations about when and where PFAS-containing foams were used, and the likely extent of exposure for specific subgroups such as those employed at training centres and airports
  • the use of Agency records of the use of the foams by individual firefighters.

The cancer incidence and mortality of higher and lower PFAS-exposed firefighter groups would be compared. These analyses would look at long term health effects and the within cohort comparisons to reduce confounding variables by comparing similarly selected and recruited firefighters with likely similar, life styles for example, socio-economic status, alcohol and tobacco consumption.

The association between PFAS exposure and cancer incidence, specifically testicular and kidney cancer, will be investigated. Other outcomes, such as thyroid, liver or kidney disease will be investigated by linkage to routinely collected health data sets, such as the Medical Benefits Scheme.

Progress report 30 April 2023

Delays to progress have been experienced due to difficulties engaging with stakeholders which is in part due to reorganisation of Victorian Fire Service. Recruitment has improved post June 2022 due to increased stakeholder support.

An Advisory Group has been established and exposure data collected from two fire agencies with three agencies actively preparing data for the study. Ethics approval is underway to enable linkage to hospital data.

 

Assessing effectiveness of PFAS exposure control in individuals from exposed communities and occupationally exposed cohorts such as fire fighters (1179111)

  • Professor Jochen Mueller (Chief Investigator A)
  • University of Queensland
  • Budget: $2,208,009.60
  • Funding period: 2020 to 2024

Project Synopsis

Trends in serum concentrations of PFAS measured in cross-sectional pooled serum studies in Australia demonstrate that exposure to most routinely studied and bio-accumulative PFAS has substantially declined in the general population over the last two decades. This demonstrates that regulation of PFAS use in consumer products has been very effective. However, there are a number of communities and work cohorts that have experienced ‘above normal’ exposure. Our team has worked in/with these communities and with exposed firefighting cohorts and we have identified approximately 500 to 1000 individuals with elevated PFAS serum concentrations. We do not know whether the blood levels in these individuals have decreased over time, whether some individuals have faster reductions in levels than others, and what the predictors of rate of decline are. Hence, the aim of our proposed project is to identify and recruit individuals with elevated PFAS concentrations from various exposed communities and the firefighting cohorts, establish longitudinal trends in PFAS concentrations and, where available, relevant health biomarkers. We will use this information to identify individuals and associated factors that can be related to fast PFAS clearance versus slow clearance/lack of clearance/increase and determine ongoing exposure/exposure pathways for individuals for which clearance remains unsatisfactory. Furthermore, we will use the gained information to model (and date) individuals peak serum concentrations for relevant (elevated) PFAS. The models we develop will assist in other epidemiological studies.

Progress report 30 April 2023

To date, 842 participants have provided blood samples and completed a survey. Additional sample collections were conducted for some existing and new participants due to a contamination event in late 2022. The collection of data, blood samples and surveys, will wind up mid-2023.

Initial planning has commenced for the external exposure sub-study. Samples of air, dust, drinking water, soil and home-grown foods will be collected from the study participants living in households in the communities that have been affected by environmental contamination. These samples will be analyzed for PFAS to assess potential exposure sources and will help to understand why some participants may not be decreasing in PFAS serum concentrations over time. Sampling is planned for October to November 2023.

Planning for future community forums are also underway; affected groups and the wider general public will be kept up to date with the outcomes of the study through community forums. The forums will enable the community and other interested individuals to engage with researchers to understand the goals of the project, discuss the outcomes and pose questions. For more details go to Assessing effectiveness of PFAS exposure control in exposed communities and firefighters.

The second phase of blood sampling will commence at the beginning of 2023 and will provide an additional timepoint of PFAS serum concentrations which is needed to assess the temporal trends of PFAS over time and how these levels have changed in the last two years. 

Publications and other resources

Nilsson,S., Bräunig,J., Carey,R.N., Hui,J., Smurthwaite,K., Toms,L.M., Kirk,M.D., Mueller,J.F. andFritschi,L. (2023). Longitudinal measurements of per- and poly fluoroalkyl substances (PFAS) in archived human serum samples between 1975 and 1995 in Australia. Journal of Hazardous Materials, 443, p.130307.

The above study was presented as a poster presentation at the 2022 Biobanking- Blue Sky Horizons (Australian Biospecimen Network Association 19th Annual Conference), 19th-21st October 2022.

 

Comprehensive characterisation of the PFAS exposome (1185347)

  • Professor Kevin Thomas (Chief Investigator A)
  • University of Queensland
  • Budget: $867,672
  • Funding period: 2020 to 2024

Project Synopsis

Per- and polyfluoroalkyl substances (PFAS) are environmentally ubiquitous and frequently detected in humans worldwide. The OECD has to date identified >5,000 PFAS in use globally. Ninety percent of these have been identified as potential precursors to specific PFAS that bioaccumulates in humans (for example, perfluoroalkyl acids [PFAAs]). Transformation of PFAS precursors in the environment, or in humans (in vivo), can therefore lead to additional, indirect exposure pathways for bioaccumulative PFAS. Despite the high number of known PFAS to be in use, targeted biomonitoring typically looks for a limited number of ~30 analytes using tandem mass spectrometry (LC-MS/MS). Notably, current biomonitoring programs generally exclude precursors and to be effective, also need to reflect new fluorinated compounds released by industry to replace those phased out of production. In addition to the routinely monitored PFAS, up to 750 other PFASs have been reported to occur in the environment, identified using non-targeted high-resolution mass spectrometry (HRMS) techniques. Australians, and others elsewhere in the world, are therefore undoubtedly exposed to more PFAS compounds than those typically measured in human biomonitoring programs, either directly or through the transformation of precursors. Recognition of the PFAS exposome, i.e., the totality of human environmental exposures to the numerous PFAS compounds, is therefore likely to be limited amongst stakeholders, for example, exposed individuals, the general population and public health regulators. The PFAS exposome unknowns represent a considerable source of uncertainty for ascertaining potential human health risks. With greater understanding and quantification of the PFAS exposome comes improved assessment of PFAS exposure that will facilitate increased understanding of any potential health effects. Alongside this, is an important task to communicate and contextualise what the PFAS exposome means for exposed individuals and the wider population.

Progress report 30 April 2023

A non-target and suspect screening high resolution mass spectrometry workflow for identifying novel PFAS has been developed. To confirm that the workflow works it was applied to pooled serum and blood from cows that were known to be exposed to high levels of PFAS from contaminated groundwater. Thirty PFAS were confirmed to be present at various levels of confidence (Level 1a - 5a), including three novel compounds belonging to two different classes. A biotransformation intermediate, hitherto unreported in biological samples, was detected in both whole blood and serum. Further, perfluoroalkylsulfonamides, including perfluoropropane sulfonamide (FPrSA), perfluorobutane sulfonamide (FBSA) and perfluorohexane sulfonamide (FHxSA) were predominantly detected in whole blood, suggesting that these accumulate in the cell fraction of blood. Suspect screening revealed several fluoroalkyl chain substituted PFAS, including chlorinated perfluorooctane sulfonate (Cl-PFOS, C8HO3F16SCl, level 1b), H-substituted perfluorooctane sulfonate (H-PFOS, C8H2F16O3S, level 3a) and keto-perfluorooctane sulfonate (K-PFOS, C8HO4F15S, 3a). The results suggest that targeting only the major PFAS in plasma or serum of AFFF-exposed mammals likely underestimates the toxicological risks associated with exposure. This work has been submitted for publication and at the time of reporting is under peer-review.

Current work is focused in applying the developed workflow to samples of pooled human serum from de-identified occupationally and generally exposed people. These complex data sets are currently under evaluation with the aim of screening the data to identify the PFAS present. The project is also actively recruiting participants to take part in a survey with the goal of enhancing health communication about PFAS exposure pathways.

For more details on this project see Comprehensive characterisation of the PFAS exposome.

 

Utilising male fertility as a biomarker of health to understand the biological effects of PFAS (1189415)

  • Professor Brett Nixon (Chief Investigator A)
  • University of Newcastle
  • Budget: $1,301,122
  • Funding period: 2020 to 2024

Project Synopsis

Our multi-site multidisciplinary team of experts will harness the acute sensitivity and responsiveness of male fertility to environmental toxicant exposure, as a proven reliable biomarker of health, to deliver an evidence-based assessment of PFAS impacts in communities across Australia.

Aim 1: Study how blood PFAS profiles are associated with sperm parameters in three cohorts; a high-exposure group living in five contaminated ‘red zones’ near Department of Defence bases across Australia; a general population cohort from communities close to these red zones, and lastly; an occupationally-exposed cohort of firefighters.

Aim 2: Utilise a transgenerational animal model to determine the causal molecular mechanisms and direct effects, from exposure to drinking water contaminated with PFAS profiles of affected communities.

Aim 3: Assess the efficacy of an innovative remediation strategy in our animal model. Namely, to feed hemp protein extracts, which we have proven to be extremely effective in sequestering PFAS, to ameliorate adverse health sequelae associated with PFAS exposure. Ultimately, our research will be conducted in close collaboration with communities to fulfil their need for information and a long sought-after solution to PFAS contamination.

Progress report 30 April 2023

The ability to recruit human volunteers to assess the impact of PFAS exposure on male reproductive health has been unavoidably compromised by the COVID-19 pandemic. Accordingly, the research team has focused its activities on the mouse studies described in the initial proposal during this time. As restrictions around the pandemic lifted, the drive to recruit volunteers commenced.

Two major mouse studies have been completed which assess the direct impact of PFAS exposure on sperm biology (in vitro study) as well as a 3-month whole animal PFAS exposure model (in vivo study). The in vitro study revealed that direct PFAS exposure was not cytotoxic to spermatozoa and nor did it overtly influence their functional profile, with normal rates of capacitation and in vitro fertilization recorded. PFAS treatment of spermatozoa did, however, result in a significant delay in the development of the pre-implantation embryos they fertilised. Such development delays were not attributed to a loss of sperm DNA integrity or an elevated burden of oxidative lesions, thus raising the prospect that PFAS exposed spermatozoa may harbor alternative stress signal(s) that are conveyed to the embryo at the moment of syngamy. Similarly, the in vivo study has also shown that paternal PFAS exposure can lead to altered patterns of embryonic gene expression. Both studies are being prepared for publication.

 

Impact of exposure pathway and source on PFAS absorption and bioavailability (1186337)

  • Professor Albert Juhasz (Chief Investigator A)
  • University of South Australia
  • Budget: $1,398,763.20
  • Funding period: 2020 to 2024

Project Synopsis

A fundamental knowledge gap when assessing PFAS health effects is an understanding of exposure; the extent of PFAS absorption (i.e. bioavailability) following ingestion, inhalation or dermal contact with PFAS-contaminated media. As bioavailability influences the dose available to exert a toxicological effect, understanding bioavailability is critical for assessing the risk of exposure to PFAS sources.

This project leverages UniSA’s recognized strengths and world class reputation in contaminant exposure assessment through collaboration with public health researchers, medical researchers, environmental chemists, environmental regulators, risk assessors and the community. The multidisciplinary approach allows a fundamental understanding of PFAS bioavailability from oral, inhalation and dermal pathways and applied outcomes from the assessment of contaminated soil, dust, fruit, vegetables, meat and fish. By understanding factors influencing PFAS absorption from environmental media, this may lead to future development and application of physicochemical and / or nutritional strategies for PFAS exposure minimization.

Progress report 30 April 2023

The toxicokinetics of three key PFAS (PFOS, PFHxS and 6:2 FTS) was assessed using an in vivo rat bioassay and a liquid Chromatography with tandem mass spectrometry (LC-MS/MS) analytical approach.

All three compounds were rapidly absorbed following oral administration although elimination kinetics varied greatly between compounds. PFOS accumulation was evident in the liver, in dose-response manner, while organ accumulation was minimal for both PFHxS and 6:2 FTS. In contrast, following absorption, both PFHxS and 6:2 FTS were rapidly excreted in the urine unlike PFOS where negligible urinary excretion was observed. Toxicokinetic data will be utilised to determine suitable endpoints for the assessment of PFAS relative bioavailability in contaminated soil.

House dust samples from urban and peri-urban locations were collected, processed and characterised for PFAS concentration. Unlike most PFAS impacted soils, unknown precursors contributed significantly to the sum PFAS concentration in house dust.

 

Human exposure to PFAS and their precursors in the environment and their biotransformation processes (1189660)

  • Professor Xianyu Wang (Chief Investigator A)
  • University of Queensland
  • Budget: $509,160
  • Funding period: 2020 to 2024

Project Synopsis

Aims: To identify PFAS profiles in the environment for exposed cohorts, characterise the biotransformation processes of PFAS precursors and identify their products, and evaluate the contribution from exposure pathways of air inhalation, dust ingestion and dermal contact to the total human burden of PFAS.

Hypothesis: Air, dust and hand wipe samples are detected with both PFAS and Pre-FAS that are available for human exposure.

Precursors are transformed in vitro to end products such as PFAAs. Concentrations of PFAAs in the air, dust and wipe samples increase during the biotransformation reaction. Exposure risk via air inhalation is higher for more volatile PFAS such as Pre-FAS and the risk of dust ingestion is more important for young children. Some PFAS can be absorbed through dermal contact due to their diverse physicochemical properties. Daily intake of PFAS from the environment is a non-negligible exposure pathway when evaluating the overall human exposure risk.

Significance: Outcomes from this project are expected to contribute to quantifying human exposure to PFAS with a comprehensive understanding of exposure pathways, advancing the understanding of results from human biomonitoring studies for translating the body fluid concentration to human exposure profiling. Eventually this project will contribute to the development of risk mitigation methods for Australian affected communities.

Expected outcomes include:

  1. characterisation of PFAS in the environment, for Australian affected communities
  2. identification and quantification of PFAS that are produced from precursors during in-vitro reaction using human liver microsomes and cytosol
  3. evaluation of the contribution from so far under-recognised exposure pathways
  4. recommendations to the individuals in the affected communities on how to understand and/or reduce exposure to PFAS.

Progress report 30 April 2023

The cohort recruitment and sample collection were impacted by COVID-19 pandemic. The research team established a solution where the consent forms and sampling devices have been mailed to the participants. The sample collection progress has been well on track based on this solution.

A total of three firefighting stations have participated in the study and over 100 environmental samples from PFAS affected areas have been collected and the overall sample collection progress is completed. The first set of samples have been analysed and results showed overall higher concentrations of PFAS compounds in firefighting stations compared to general offices. General offices are sites not known to be exposed to PFAS contamination specifically related to fire suppression. For this study, samples were collected from university offices located in Brisbane. The sample analysis and data processing for the rest of the firefighting station samples are in progress.

A total of 50 homes in specific PFAS affected communities have been recruited and sample collection is 75% completed. Relevant questionnaire information has been collected with these samples and data analysis will be conducted against this information. The chemical analysis work has also started.

The challenges around cohort recruitment and sample collection were significant. However, risk management plans already set in place during the grant application procedure which enabled the issue to be addressed promptly. With the disruptions due to COVID-19 pandemic easing, the project work has been progressing with satisfaction.

 

Human biomonitoring of PFAS: assessing reliability and validity (1180109)

  • Dr Leisa-Maree Toms (Chief Investigator A)
  • Queensland University of Technology
  • Budget: $415,316
  • Funding period: 2020 to 2024

Project Synopsis

Our human biomonitoring program involves collection and analysis of de-identified, surplus pathology samples collected in South East Queensland which are stratified and pooled from 6 age groups (0–4; 5–15; 16–30; 31–45; 46–60; and >60 years) and sex; undertaken every two years since 2002. Limitations of this established methodology are: the inability to determine individual exposures based on pooled samples; issues of representativeness due to use of de-identified pathology “sick” samples; and concerns of spatial variation across the population of Australia since samples are sourced from South East Queensland only.

This project will evaluate and advance the reliability of biomonitoring of human PFAS exposure in Australia through the assessment of these limitations to provide new data on variance and representativeness of biomonitoring in Australia. Specifically, we will:

  • evaluate the representativeness of pooled pathology samples for assessing exposure risk
  • determine chemical concentration data by age/sex from 2020 to 2024
  • investigate both traditional and emerging PFAS.

Progress report 30 April 2023

Stage 1:  Further sampling has been undertaken and is continuing on the human biomonitoring.

Stage 2: Assess the representativeness of Human Biomonitoring (HBM) using pathology and insurance samples is complete and will be written up shortly.

Stage 3: Assess PFAS concentrations by pool size and age group – A PhD student is making good progress looking at the number of samples required per pool. Work is underway on a paper regarding one of the aims which is for targeted pooling.

Stage 4: Assess spatial variation of PFAS concentrations across Australia - data has been collected and CI Jolliet will be visiting Brisbane in June/July 2023 to work on the write up of this paper.

Stage 5: Chemical analysis for a wide range of PFAS - this is underway.

Stage 6: Data management, interpretation and dissemination - a website has been made but this will ramp up after collaboration with CI Jolliet.

 

Using advanced technologies to investigate the impact of PFAS exposure on the human mucosal barrier and interaction with pre-existing medical conditions (1186216)

  • Dr Gerard Kaiko (Chief Investigator A)
  • University of Newcastle
  • Budget: $910,060
  • Funding period: 2020 to 2024

Project Synopsis

Epidemiological research has associated increased PFAS levels with inflammatory bowel disease (IBD) and asthma. Furthermore, traditional toxicology screening, although limited, indicates that PFAS may have deleterious effects (for example, kidney/endocrine function). A major concern of the Australian Department of Health’s Expert Panel Review on PFAS and consumers, is the unknown effects of chronic exposure, dose level, and risk of an impact on human health. In this proposal we aim to identify potencies and related exposure risks (range of pathophysiological readouts) of PFAS (and combinations thereof) on human mucosal epithelial barrier (HMEB) surfaces of the intestinal tract and lung (healthy, IBD and asthmatic). These are the sites most frequently exposed to PFAS. We will employ state-of-the-art three-dimensional cellular models of human organoids (including ‘mini-guts’) to re-capitulate the function of HMEB, as this is now the gold standard for determining the potential toxic effects of chemicals/environmental compounds on human cells. The long-term impact of PFAS on the intestinal and airway barrier cells will be assessed through analysis of genomic methylation using single cell sequencing. Preclinical models of IBD and asthma will be used to assess the potential of PFAS to exacerbate disease, and if pre-existing barrier dysregulation in these disorders increases systemic transit of PFAS from the environment.

Outcomes: Identification of the pathophysiological impact of PFAS on the HMEB will establish a frame-work to inform community and the government on exposure risk and health policy, especially with regard to pre-existing IBD or asthma.

Progress report 30 April 2023

The research team has completed the first part of its work on human gut organoids, by testing the impacts of PFAS compounds, including PFOA and PFOS. This testing of PFAS compounds was completed across a large range of environmentally and contaminated-community relevant concentrations identified from PFAS contaminated areas and known concentrations of PFAS in blood from previous population analyses. This work examines whether PFAS compounds contribute to intestinal barrier problems such as those found in ulcerative colitis. Testing for both acute and chronic exposure to PFAS has been completed. To date the research team has found that PFOA and PFOS across a range of physiologically relevant doses appear to have minimal negative impact in models of healthy and diseased intestinal cell function. At very high doses, significantly above those detected in the community and only when given chronically, PFAS does appear to have a mild negative impact on function.

One of the major findings to date is that the pre-existing presence of models of colitis and the inherent leaky intestinal epithelial barrier in preclinical models appears to increase the levels of PFAS in the serum compared to the healthy non-colitis state with a healthy intestine. This suggests the possibility of reverse causation, explaining the correlation link established between PFAS and ulcerative colitis in contaminated communities a decade ago from population studies. This work suggests that PFAS is linked to ulcerative colitis epidemiologically because of pre-existing biological features of the disease itself rather than because PFAS is causing colitis. The research team aims to publish the first half of its work on PFAS in the gut within coming months in a top environmental science journal and distribute the findings through the Cooperative Research Centre for Soil  network to reach the community.