GUIDELINES to deal with sites contaminated with the chemicals contained in firefighting foams once used at Pearce air base show the potential problems government departments and the community face if the chemicals are found anywhere in toxic levels.
While the Department of Defence continues to test for the presence of perfluorooctanoic acid and perfluorooctane sulfonate at the base and nearby properties the Federal Government is holding an enquiry into the health effects of the chemicals with the results due by the end of this month.
Meanwhile, the WA Department of Environment Regulation interim guideline on the assessment and management of perfluoroalkyl and polyfluoroalkyl substances says perfluorooctanoic acid and perfluorooctane sulfonate are known to be persistent, bioaccumulative and toxic and, due to their persistence in the environment and moderate solubility, can be transported long distances (potentially kilometres) in water and air, and transfer between different media (for example soil, sediment, surface water and groundwater).
In August 2010 both the chemicals were added to Annex B of the Stockholm Convention on Persistent Organic Pollutants, which Australia has yet to ratify.
As well as being used in firefighting foams the chemicals are widely used in a range of industrial applications, such as textiles, preservatives, fluoropolymer and fluoroelastomer production, surface treatment, food packaging, hydraulic oil for aeroplanes, cosmetics, floor wax, polish, paint and lacquer.
The guidelines said perfluorooctane sulfonate and perfluorooctanoic acid are moderately soluble and have surface water half-lives of 41 years and 92 years respectively.
“[The chemicals] have the potential to bioaccumulate and biomagnify in food webs as evidenced by their detection in fish and fish-eating birds,’’ the guidelines said.
“To date, perfluorooctane sulfonate is the only PFC that has been shown to accumulate to levels of concern in fish tissue (estimated bioconcentration factor of 1000 – 4000, US EPA 2014).’’
Echo News asked the Department of Defence and the WA Deprtment of Health if potentially the chemicals could have escaped into the Ellen, Ki-it Monger and Nambah brooks and then into the Swan River.
A Department of Defence spokesman said the department started a detailed environmental investigation at Pearce in May.
“The next stage of the investigation will involve water and sediment sampling to establish the extent of the presence of [the chemicals] in the investigation area,’’ he said.
“This will include sampling from local water ways.
“The investigation is expected to be complete in early 2017.’’
He said as the department received verified results for the air base it would make the results available to relevant landholders and state authorities.
“The next community information session to discuss the current results of the investigation is expected to be held in September 2016.
“The community consultation will provide information on the progress of the investigation and the next steps.
“This will enable the community to ask questions and for Defence to work with local residents to share information.
“Defence remains committed to being open and transparent with local communities during the investigations.”
The WA Department of Health was still to respond when Echo News went to press but enHealth (the Environmental Health Standing Committee of the Australian Health Protection Principal Committee) website said because of their widespread use, most people in Australia will have some of the chemicals in their body.
“Perfluorooctanoic acid and perfluorooctane sulfonate are readily absorbed through the gut, and once these chemicals are in a person’s body it takes about two to nine years, depending on the study, before those levels go down by half, even if no more is taken in,’’ enHealth said.
As well as occupational setting, exposure to the chemicals could happen from the air, indoor dust, food, water and various consumer products with food expected to be the primary source of exposure to for most people.
Human breast milk may contribute to exposure in infants [as the chemicals] have been detected in human breast milk.
“In chronic exposure studies on laboratory animals, research into [the chemicals] has shown adverse effects on the liver, gastrointestinal tract and thyroid hormones however, the applicability of these studies to humans is not well established.
“A blood test can measure the level of [the chemicals] in a person’s blood and can tell a person concerned about exposure how their blood levels compare with the levels seen in the general Australian population.’’
But enHealth said there was at present insufficient scientific evidence for a medical practitioner to be able to tell a person whether their blood level would make them sick now or later in life, or if any current health problems were related to the perfluorooctanoic acid and perfluorooctane sulfonate levels found in their blood.
This meant blood tests were not recommended for the purpose of determining whether an individual’s medical condition was attributable to exposure to the chemicals.
By Anita McInnes