The National Health and Medical Research Council (NHMRC) has recently unveiled updated draft guidelines concerning per- and polyfluoroalkyl substances (PFAS) in drinking water. This significant development aims to enhance the safety of water supplies across Australia, addressing a growing concern regarding these persistent environmental contaminants.
The new draft guidelines specifically focus on four main PFAS chemicals: perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS). These substances have been widely used in various industrial applications and consumer products, raising alarms about their potential health impacts. Additionally, the guidelines incorporate information on hexafluoropropylene oxide dimer acid and its ammonium salt, commonly referred to as GenX chemicals.
These health-based guideline values are designed to be conservative and protective of human health, grounded in thorough evaluations of the latest scientific evidence. The NHMRC emphasizes that these guidelines will inform state and territory strategies for ensuring the safety of drinking water supplies.
Public Consultation and Future Guidelines
As part of the guideline development process, the NHMRC is inviting public submissions on the draft guidance until Friday, 22 November 2024. The Water Quality Advisory Committee, in collaboration with the NHMRC, will review all submissions, indicating that the proposed PFAS guideline values may still undergo changes before they are finalized. The final guidance material is expected to be published as part of the Australian Drinking Water Guidelines in April 2025, while the current guidelines remain in effect until then.
Understanding PFAS and Their Health Impacts
Dr. Ian Musgrave, a Senior Lecturer in Pharmacology at the University of Adelaide, sheds light on the nature of PFAS. These compounds are highly fat-soluble and resistant to breakdown, leading to their persistence in the environment and accumulation in the human body. Dr. Musgrave notes that it can take up to five years for half of an ingested dose of PFAS to be eliminated from the body, raising concerns about potential adverse health effects from prolonged exposure.
Since the phased-out industrial use of PFAS in Australia began in the 2000s, levels detected in the population have gradually decreased. However, the primary exposure route now remains through environmental contamination, particularly in drinking water sourced from affected areas. The NHMRC periodically reviews health evidence related to PFAS to update the drinking water guidelines, with the last review occurring in 2018.
The latest review has led to a downward revision of PFAS limits in drinking water. For instance, the previous combined limit for PFOS and PFHxS was set at 70 ng/L, which has now been revised to 4 ng/L for PFOS and 30 ng/L for PFHxS. Similarly, the limit for PFOA has been reduced from 560 ng/L to 200 ng/L. Dr. Musgrave reassures that most potable water supplies in Australia either have no detectable PFAS or already meet the new limits, indicating limited health impacts from these revisions.
Global Context and Comparisons
Denis O’Carroll, a Professor at UNSW Sydney, emphasizes the global context of PFAS regulation. With over 14,000 chemicals classified as PFAS, the health concerns surrounding these substances are significant. The World Health Organization categorizes PFOA as a Group 1 carcinogen and PFOS as a Group 2B carcinogen, highlighting the serious health implications associated with these compounds.
O’Carroll points out that the proposed Australian drinking water guidelines are less stringent compared to those in the European Union, the United States, and Canada. For example, Health Canada recommends a combined limit of less than 30 ng/L for all PFAS, while the European Union suggests a limit of 500 ng/L for the sum of all PFAS or 100 ng/L for a select group of 20 PFAS. In contrast, the U.S. Environmental Protection Agency has established specific limits for PFOS and PFOA at 4 ng/L, among others.
O’Carroll advocates for a broader inclusion of PFAS in Australian drinking water guidelines, similar to practices in other countries. He stresses the need for extensive mapping of PFAS contamination in Australian water sources and calls for government funding to better understand the health and environmental risks posed by a wider range of PFAS chemicals.
Monitoring and Management of PFAS
Dr. Daniel Deere, a Water and Health Consultant at Water Futures, reassures the public that Australia is fortunate in having minimal water supplies affected by PFAS. Concerns are primarily localized to specific hotspots, such as areas near airports or firefighting training grounds, where PFAS has been extensively used. These sites are actively monitored and managed to mitigate risks.
Public water supplies in Australia are managed by professionals who are committed to ensuring the safety of drinking water. Dr. Deere emphasizes that if PFAS levels pose a health risk, authorities will promptly notify the public and take necessary actions to resolve the issue, such as changing water sources or implementing PFAS removal treatments.
As Australia navigates the complexities of PFAS regulation and public health, ongoing research and community engagement will be crucial in shaping effective guidelines and ensuring the safety of drinking water for all Australians.