Formatted Title
PFAS in Dust Measurement: Environmental and Occupational Considerations
Background/Objectives
Airborne PFAS has been evidenced in previous studies that have detected presence of PFAS in various environments, including house dust, settled dust at fire stations and training facilities, aerosols associated with wastewater treatment plants (WWTPs), and the natural environment. Recognizing the significance of inhalation as a pathway for PFAS uptake, Food Safety Australia and New Zealand (FSANZ) has acknowledged its role in human exposure alongside ingestion and dermal contact.
PFAS can become airborne through multiple mechanisms, such as the volatilization of neutral PFAS compounds like fluorotelomer alcohols, the aerosolization of ionized PFAS in water droplets, the generation of dust due to disturbance of PFAS-contaminated soils, crushing and cutting of PFAS-contaminated concretes, the disruption of settled dust containing PFAS, emissions from the manufacturing industry, and the disturbance of crystallized concentrated PFAS following the evaporation of aqueous film-forming foams (AFFFs) and other PFAS-containing solutions.
Despite this, there has yet to be a direct approach for measuring occupational exposure to PFAS or the transport of PFAS via airborne dust in the environment. To address this gap, a portable, practical, and robust quantitative methodology was developed that enables the quantification and assessment of human and environmental exposure to PFAS through airborne transport mechanisms.
Approach/Activities
This study collected data on PFAS in dust from various settings, including contaminated and uncontaminated environments. Dust was sampled from sources such as manufacturing, maintenance, remediation, and civil works within PFAS-impacted sites or industries. The studies were designed to measure PFAS, with a particular focus on PFOS, PFHxS, and PFOA, in occupational and human health settings. All results were back calculated to represent a percentage of the FSANZ tolerable daily intake (TDI).
Data were collected from built urban environments (residential and commercial-industrial settings), rural environments and public open spaces, offices, manufacturing facilities, PFAS-contaminated sites during lightly intrusive works and remedial activities, and residential construction adjacent to a PFAS-impacted site. The collected data from these activities underwent further analysis to support the development of an assumptive model for estimating PFAS exposure.
The findings from the field trials, along with the utility of a model, are presented in this study. The findings contribute to the conceptualization of risk and inform the future potential requirements for addressing the current knowledge gaps.
Results/Lessons Learned
The studies have revealed that airborne PFAS exposure can readily exceed the FSANZ TDI for PFOS+PFHxS (0.02 µg/kgbw/day) highlighting an exposure pathway that has not received sufficient attention in the assessment of PFAS risk. This is also true when evaluating certain modes of offsite or transboundary transport. The research has demonstrated that specific conditions are necessary for PFAS to pose a risk to human health through inhalation, enabling various management options.
The transportation of PFAS through the attachment to dust particles across site boundaries, as well as the inhalation exposure of workers and environmental receptors, poses a novel challenge in PFAS management. The data set, model, and gap analysis presented in this study mark the initial strides towards establishing suitable monitoring and exposure datasets that can effectively characterize the risks associated with this particular exposure pathway. By addressing this challenge, we can develop more targeted and informed approaches to mitigate the risks posed by PFAS in dust and ensure effective management.