Per- and poly-fluoroalkyl Substances (PFAS) are a group of man-made chemicals that have been widely used since the 1950s in household and industrial products that resist heat, oil, stains, grease and water. This included non-stick cookware, food packaging, stain protection applications to fabric, furniture and carpet, and fire-fighting foams. Since 1970, firefighting foams (FFFs) containing PFAS were used extensively in Australia and elsewhere due to their effectiveness in fighting liquid fuel fires. As such, all current and historical fire-fighting training grounds and areas where aqueous FFFs have been stored or used in large quantities should be considered as a potential source of contamination. There are many types of PFAS, with the best known examples being perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).
Over the years, FFFs containing PFAS have found their way into adjacent waterways. PFAS chemicals persist in the environment, are bioaccumulative, toxic to plants and animals, and highly mobile. They are difficult to risk assess for a number of reasons such as poor historical knowledge / record keeping; manufacturer reluctance to disclose ingredients (in Safety Data Sheets for instance); the fact that there are 3,000 odd PFAS chemicals and various homologues, intermediates and transformation compounds; and their toxicology is poorly understood.
Due to their potential links with serious human health effects such as cancer (e.g. kidney and testicular), thyroid disease, liver disease, increase in blood cholesterol, depression of the immune system and development issues in children; PFAS chemicals have received a lot of media, government and community attention. The Australian Government Department of Health indicates that there is currently no consistent evidence that exposure to PFAS causes adverse human health effects. Given these chemicals tend to remain in the body for long periods of time and studies have suggested they produce adverse health outcomes in animals, it is recommended that as a precaution, human exposure to PFAS should be minimised.
The primary exposure pathways in the workplace are inhalation of spray mist and dust contaminated with PFAS. Drinking of PFAS-contaminated water may also be an important exposure pathway. Dermal (skin) contact with PFAS is not considered a significant exposure pathway. The dominant source of PFAS exposure for the general population is ingestion of food contaminated with PFAS.
Whilst blood testing is available to determine total exposure levels, it is not considered helpful to manage any current medical problems or to predict future health problems. It should also be noted that blood testing could not differentiate between workplace and other exposures. Whilst there is no level of PFAS in blood that is considered ‘normal’ or ‘abnormal’ the level of PFAS in a person’s blood can tell a person about their exposure to PFAS and how their blood PFAS levels compare with the levels seen in the general Australian population. The monitoring of pooled community blood samples over time may help determine the success of exposure reduction measures.
There are health based guidance values for use in site investigations in Australia (refer Table 1). Health based guidance values indicate the amount of a chemical in food or drinking water that a person can consume on a regular basis over a lifetime without any significant risk to health.
Table 1 Health Based Guidance Values for PFAS
Food Standards Australia New Zealand (FSANZ) have not established a TDI for PFHxS however have advised that the TDI for PFOS is likely to be conservative and protective of public health.
The Heads of EPAs Australia and New Zealand (HEPA) (2018) and WA DWER (2017) also provides soil guidance or human health screening values to assess potential human exposure through direct soil contact.
The risk of exposure to PFAS must be mitigated where possible, avoiding work in or near PFAS contaminated sites and not to use groundwater, bore water, surface water or home grown produce from those areas. Where elimination is not possible, the risk of exposure must be assessed and managed in accordance with the hierarchy of exposure controls and as far as reasonably practicable. Safe work procedures should be developed where required with consideration of recommendations given in the Safety Data Sheets (SDS). It is particularly important for people to avoid incidental ingestion. Generation of spray mist and dust contaminated with PFAS also should avoided or else minimised.
Personal Protective Equipment (PPE) should be used where a residual risk remains and with consideration to the type and level of contamination, and exposure pathway. PPE may include boots, respirators, gloves, and chemical protective clothing.
Many countries have phased out, or are in the process of phasing out the use of PFAS due to concerns about their persistence, bioaccumulation and toxicity. These restrictions have resulted in a general trend towards lower PFAS levels in a person’s body.
The Australian Government has been working since 2002 to reduce the importation of some PFASs and has recently committed to a number of health initiatives to assist communities affected by PFAS contamination.
In Western Australia, persons that are responsible for land known or suspected to be contaminated with PFAS have a duty to report that site using the prescribed form. The 2017 Department of Water and Environment Regulation (DWER) Contaminated Sites Guideline: Identification, Reporting and Classification of Contaminated Sites in Western Australia should be referred to for further information on reporting known and suspected contamination.
Persons responsible for a site must also undertake appropriate assessment and remediation action, commensurate with the risk posed to human health, the environment and environmental values. The 2017 DWER Contaminated Sites Guidelines: Interim Guideline on the Assessment and Management of Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) should be consulted along with the 2018 HEPA PFAS National Environmental Management Plan.
There are recognised controls options for contaminated soils or sediments which include landfill disposal, encapsulation in purpose-lined repositories, thermal desorption and pyrolysis. For groundwater, the most common treatment methodology is extraction and filtration through Granular Activated Carbon (GAC) although other adsorbents have been used. The regeneration/chemical treatment or disposal of spent-adsorbent also requires consideration.
If you have any concerns over PFAS, whether it is for more information or for investigating levels in soil or water, please give the team at OHMS a call and we will be happy to assist with your enquiry.