The Expert Panel examining the contamination threat from a toxic leak at the Williamtown RAAF base, near Newcastle, has recommended lifting a temporary ban on oyster harvesting.
However, the Panel has advised that a ban on commercial and recreational fishing should continue for the time being after some species were found to contain Perfluorooctanesulfonic acid (PFOS) at levels which cause some concern.
Those test results will now undergo further analysis, while a wider fish sampling strategy will be developed in consultation with industry as quickly as possible before being implemented.
NSW Chief Scientist & Engineer, Professor Mary O'Kane, who is Chair of the Panel, said the results are mixed.
"The Panel considered the preliminary test results, as well as advice from the NSW Food Authority, NSW Health and Food Standards Australia and New Zealand, and determined oysters from the Tilligerry Creek Harvest Area do not pose a food safety risk – and there is no reason to keep the ban in place," Professor O'Kane said.
"However, the early test results for some fish species show increased levels of PFOS – therefore, as a precaution, the Panel has recommended the ban continue until we have a clearer understanding of what the results mean," she said.
The fishing closure will remain in effect for Tilligerry Creek and Fullerton Cove until 31 October 2015.
Meanwhile, bore water testing is continuing and as results become available they will be considered by the Expert Panel.
And Professor O'Kane has acknowledged community interest in baseline blood screening for PFOS – noting a clinical toxicologist sits on the Panel to provide expert advice on the issue.
"Professor Alison Jones, the Executive Dean of Science, Medicine and Health at the University of Wollongong, has been appointed to provide independent expert advice on this and other potential health-related issues," she said.
Professor Jones said there is no evidence that blood screening for PFOS provides any clinical benefit.
"At this stage, because of gaps in scientific knowledge, blood testing can provide no useful information about risk to an individual's health, assist with diagnosis or provide treatment information," Professor Jones said.
"In effect, the results are uninterpretable for a person tested, and provide no guidance about what advice to provide, treatment to offer or risks to expect.
"Also, we know that we all will have some measurable PFOS in us – from a variety of exposures – so nobody can be reassured by a zero test, as that will almost certainly not occur," she said.
The Williamtown Contamination Expert Panel was set up by the NSW Government to explore the nature and extent of contamination from fire-fighting foams used historically at Williamtown RAAF Base and recommend next steps.