Navy update on chemicals
The Department of Defence hosted a community walk-in session at Quest Rockingham last Thursday, revealing the next stage of its investigation into toxic firefighting chemicals found on HMAS Stirling in 2016.
Two years ago, chemicals called perfluoroalkyl and polyfluoroalkyl substances (PFAS) were detected at the naval base, with independent environmental consultant RPS Group engaged to carry out an investigation.
PFAS was initially used in firefighting foams on the island, and a number of other defence bases around Australia, until it was phased out in the early 2000s.
A preliminary site investigation was carried out in July 2017 before a detailed site investigation involving the sampling of soil, sediment, pore water, surface and ground water was carried out.
Director for PFAS investigations for the Department of Defence, Rachel Rees-Scott, said the findings showed there was no risk to humans.
“There are, however, questions that we have about ecological health — so we are doing a little bit more work to understand the effects that the PFAS might have on the environment,” she said.
Leading consultant from RPS Group, Colm Corcoran, said the main findings from the site investigation reported there was PFAS impact to soils in each of the source areas, albeit at very low levels.
“PFAS that are present have the potential to leach into groundwater underneath the island, and that groundwater discharges into the marine environment,” Mr Corcoran said. “So as a result of a release of foams on the island, there’s the potential for impact to the near shore marine ecology around the island.”
As part of the next stage of its ecological risk assessment, the investigation will collect and analyse data from biota near the shore of HMAS Stirling, including sand worms, sea grass and filter feeders.
Should PFAS be detected at this point then consideration will be given to collecting samples from fish and other animals.
Fears also over the potential contamination of the wider Cockburn Sound area were allayed, after an investigation from the Cockburn Sound Management Council in April 2017 found there was no evidence of PFAS contamination.