Measuring & Managing the Risks of PFAS in Dust
By Tim Dowle
Currently, inhalation is an overlooked exposure pathway for PFAS, when compared to ingestion. While ingestion of food and water is intermittent or incidental, when present in contaminated environments, we must breathe continuously, and this can involve the inhalation of dusts that contain PFAS. Coupled with probable exposure to PFAS in dust across a wide range of land uses, and the potential for PFAS to migrate offsite within dusts, it is then more appropriate to consider PFAS exposure via food, water and dust.
Modelling suggests that humans are exposed to diffuse low-level chronic exposure to PFAS in dusts, possibly along with high-level acute exposure. Chronic exposure could comprise exposure in homes, offices or commercial spaces where products that contain PFAS exist e.g. carpets, fabrics, packaging, cosmetics etc. Acute exposure is related to specific extreme dust generation events such as high winds and / or vigorous activities. Some examples include residues from aircraft hangar foam deluge systems, firefighting foam residues / salts, drying-out evaporation basins (stormwater drainage) and soil disturbance and remediation e.g. soil disposal / treatment / stabilisation for PFAS.
Until now, there has been no direct method for measuring PFAS exposure in dust. Existing approaches, primarily focused on general dust measurement, could not provide this specific data. Previous methods involved vacuuming surfaces and swabbing to estimate PFAS exposure indirectly, which had several limitations.
Our Solution
ADE’s new technology involves air quality monitoring in the field using standard occupational health equipment, which can comprise personal monitoring e.g. lapel mounted samplers (mobile) or environmental air monitoring e.g. site boundary samplers (static). Using a typicaleight-hour sampling period, samples containing dust are submitted to ADE’s partner laboratory and analysed for PFAS using our NATA-accredited method, the first such approved method in Australia. After quantitation, results are compared against Food Standards ANZ Tolerable Daily Intakes (TDIs) for PFOS and PFOA.
Our Solution
ADE’s new technology involves air quality monitoring in the field using standard occupational health equipment, which can comprise personal monitoring e.g. lapel mounted samplers (mobile) or environmental air monitoring e.g. site boundary samplers (static). Using a typicaleight-hour sampling period, samples containing dust are submitted to ADE’s partner laboratory and analysed for PFAS using our NATA-accredited method, the first such approved method in Australia. After quantitation, results are compared against Food Standards ANZ Tolerable Daily Intakes (TDIs) for PFOS and PFOA.
Application and Benefits
The advantages of this new approach are numerous. It offers adaptability and portability, making it applicable in various scenarios and locations. Its technical prowess allows for the measurement and management of direct occupational exposure to PFAS through standardised sampling equipment, and it can quantify airborne PFAS mass flows to the environment.
The use of commonly available equipment ensures data can be collected promptly, enabling timely actions to mitigate risks associated with PFAS in dust. The tool is mobile, adaptable, simple to use, and provides a crucial analytical measure for assessing human health and environmental risks.
Key Applications & Benefits
- Occupational Health – Protection of workers from direct PFAS exposure
- Public Health – Protection of sensitive offsite receptors e.g. residential
- Environmental – Inform site environmental management e.g. dust suppression
- Dynamic Monitoring – Portable samplers, mobile lab delivering real-time data
- State of Knowledge – Collation and assessment of metadata to better define risks
Key Applications & Benefits
- Occupational Health – Protection of workers from direct PFAS exposure
- Public Health – Protection of sensitive offsite receptors e.g. residential
- Environmental – Inform site environmental management e.g. dust suppression
- Dynamic Monitoring – Portable samplers, mobile lab delivering real-time data
- State of Knowledge – Collation and assessment of metadata to better define risks
Case Studies
Recently ADE’s PFAS in dust methodology was deployed on two separate sites to monitor the potential exposure of workers to PFAS in dust, or migration of PFAS in dust across site boundaries during intrusive works. These studies are summarised here.
Application at a Wastewater Treatment Plant
ADE’s client was undertaking due diligence testing to protect workers involved in trenching activities on a capital works program located in a former spray field. The site soils were known to be PFAS impacted at relatively low concentrations.Monitoring found that PFAS were non-detect in air samples collected during works, suggesting that the exposure of workers on the site was <1% of the TDI for a 78 kg human over a 10-hour shift. This allowed the client and their contractor team to progress the project with confidence, with quantifiable evidence supporting that the health of workers was not at risk due to any potential PFAS in dust exposure via inhalation.
Monitoring At a Former Fire Training Facility
ADE undertook baseline monitoring at a former fire training facility where intrusive works were earmarked tooccurfor a future site development project. Soil concentrations for PFOS and PFHxS at the site were significantly elevated and ranged from approximately 1mg/kg to 100 mg/kg.Monitoring was conducted across the site in a crosshairmonitoring design, at various distance intervals from the centre of the site. Further monitoring was undertakenat the site boundary.
Monitoring found that the mean exposure to PFAS via inhalation of dusts at the site, under ambient conditions with no soil disturbanceand during a rain event, could result in a mean PFOS+PFHxS exposure of 10.8 % of the TDI for a 78kg human, via the inhalation pathway. Results for one particular monitoring pointadjacent to a haulage road demonstrated that the passing of approximately 1 to 2 heavy trucks per hour resulted in an exposure of 57% of the PFOS +PFHxS TDI. All values were calculated assuming similar toxicological profile for PFOS an PFHxS and exposure of a 78kg human over a 10-hour shift. These results can be used to modify environmental management practices at the site, but will also be compared to further monitoring during intrusive works to assess impact of soil disturbance and identify any potential risks which may require further management.
Tim Dowle
Principal Environmental Consultant
Business Unit Manager -
Emerging Contaminants, Treatment, Remediation and Research
