Seafood in popular Darwin fishing spots contaminated by toxic foam
Creeks found to be contaminated by decades-long use of poisonous firefighting foam, studies show. 11 Oct 2017
Seafood in two creeks near Darwin airport is contaminated with toxic firefighting chemicals at levels similar to the notorious Williamtown red zone, research has found.
The Northern Territory government on Thursday released the results of two contamination studies at Rapid and Ludmilla creeks.
The creeks are popular fishing spots, including for the local Indigenous community, but are thought to have been contaminated by decades-long use of toxic firefighting foam, including at the nearby Darwin international airport and RAAF base.
One study, conducted by the University of Queensland, found all species of fish and crabs had higher mean per- and poly-fluoroalkyl substances (Pfas) levels than a comparison site.
The worst results found in mudcrabs in Rapid Creek were worse than those detected at the notorious Williamtown airbase, near Newcastle, a known contaminated site.
“Overall, this initial study suggests that Rapid and Ludmilla Creeks are more impacted by Pfas contamination than Bleesers Creek,” the study found.
“Levels from mudcrabs, prawns and fish are mostly consistent or slightly higher than those analysed from Williamtown RAAF Base, a known Pfas-contaminated site.”
But the researchers found it unlikely the contamination would pose a health risk, unless a person was eating large amounts of seafood from the creeks regularly.
Another study, conducted by Charles Darwin University, found Pfas chemicals in two common aquatic food sources, longbums and periwinkles, at levels six to 22 times higher than a comparison site.
The Charles Darwin researchers also played down the health risk to humans.
They found only those who regularly and routinely ate a large amount of highly contaminated seafood at the maximum possible weight would be exposed to a health risk.
Both studies assumed people eating seafood from the creeks were not being exposed to Pfas in any other way, including through eating locally-grown produce or consuming contaminated water.
The soil results also showed a significantly higher concentration of Pfas than elsewhere. One of the chemicals perfluorooctanoic acid (Pfoa) was found in sediment samples at two to eight times the level of the comparison site, while perfluorooctane sulfonate (Pfos) and were Perfluorohexane sulfonate (PFHXS) were 11 to 85 times higher.
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Comprehensive studies in the US have found Pfas chemicals share probable links with cancer, pregnancy-induced hypertension, and other illnesses.
The chemicals are highly persistent in the environment, are transferred via food sources, and bioaccumulate, meaning levels build up in living organisms over time.
In releasing the results on Thursday, the NT government cast doubt on any potential health risk.
The health minister, Natasha Fyles, said the foods could still be eaten without exceeding the safe intake levels set out in the national health based guidance values, released this year by Food Standards Australia New Zealand.
“Current research is inconclusive and it’s not known if exposure to Pfas causes any significant health problems in people, but the potential for adverse health effects can’t be ignored,” Fyles said.
“The commonwealth is taking a precautionary approach to this emerging national issue, introducing some of the most conservative guidelines in the world to ensure Australians minimise their exposure to Pfas.”
The downplaying of possible health impacts has been criticised by many, including the National Toxics Network.
The network’s chemical expert, Mariann Lloyd-Smith, on Thursday reiterated warnings she first made up to two years ago to avoid the creeks.
“This was something we were warning about 18 months, two years ago,” Lloyd-Smith told Guardian Australia. “It just means that a whole group of people have been unknowingly exposed yet again to chemicals that take years and years to get out of their system.
“The problem also about that creek is a lot of Indigenous people use it as recreation, they do eat the crabs.”
The federal government and the chemicals’ former manufacturer, 3M, have cast doubt on any link between human health impacts and Pfas exposure. 3M says it has 30 years of research suggesting there is no link. The defence department says the evidence has not shown any consistent or causal link with adverse human health impacts.
The man lawyer who led a major US class action over Pfas contamination, attorney Robert Bilott, disagrees.
Bilott said the health impacts of Pfoa have been well established through one of the most comprehensive epidemiological studies ever conducted.
That study involved tens of thousands of residents exposed to Pfoa in Ohio and West Virginia.