New guidance produced on safe levels of exposure and water contamination
12 April 2017 / Australia, PFCs, Risk assessment
The Australian Department of Health (DoH) has released guidance reducing acceptable exposure levels to three perfluoroalkyated substances (PFASs).
The move follows concern about contamination found in 2015 around two airports and in nearby drinking water and fish populations. Firefighting foams containing PFASs had been used at the sites until as late as 2008.
The guidance is for assessing exposure to three PFASs:
• perfluorooctane sulfonate (PFOS);
• perfluorooctanoic acid (PFOA); and
• perfluorohexane sulfonic acid (PFHxS).
Produced by Food Standards Australia New Zealand (Fsanz), the guidance includes recommended tolerable daily intake values (TDIs) – levels of daily exposure that over a lifetime present no appreciable risk to health.
It replaces interim guidance produced by the Environmental Health Standing Committee (enHealth) – part of the DoH – in June 2016. These caused controversy at the time because they were modelled on European Food Safety Authority (Efsa) standards from 2008, which were nearly 80 times higher than standards set by the US EPA in 2016.
The Fsanz TDI for PFOS and PFHxS is significantly lower than the enHealth one.
According to the Fsanz, its assessment used a pharmacokinetic modelling approach and parameters that matched the Australian context, but which differs from that used by the US EPA. The assessment is backed by the Australian Health Protection Principal Committee (AHPPC). It has been reviewed by the Australian Health Ministers Advisory Committee (AHMAC) and has been subject to international peer review.
The TDI for PFOS and PFHxS is 0.02 micrograms per kg of body weight; for PFOA the TDI is 0.16µg/kg of body weight. The safe levels in drinking water are for 0.07 micrograms per litre for PFOS and PFHxS and 0.56µg/l for PFOA.
The levels are approximately ten times lower than those issued as preliminary measures.
The Department of Health considers the setting of these levels as a "precautionary measure" as it says there is no consistent evidence that PFASs cause adverse human health effects. These TDIs will also be used to create a consistent approach as state and local authorities assess sites contaminated by PFAS.
Fsanz has also conducted a dietary exposure assessment of PFAS and produced guidance on how state and local governments should address concerns about food consumption in affected areas. It has not recommended any measures that should currently be taken on food contamination.
PFAS have been used since the 1950s both in industry and in household products. But it is their use is firefighting foams that has caused most concern recently.
The Australian government is providing support services and advice in two towns considered to be particularly affected.