Sunday, December 3, 2023

Dolphins found living with world’s highest reported PFAS levels near Melbourne, Gippsland

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A study has found critically endangered dolphins in waters off Melbourne and Gippsland contain the highest levels of PFAS chemicals reported anywhere in the world. 

Scientists from the Marine Mammal Foundation, RMIT University and the University of Melbourne took samples from 38 dolphins of multiple species along Victoria’s coastline but particularly high levels were found among the Burrunan dolphin population.

Record concentrations of the chemicals were recorded among Burrunan dolphins of Port Phillip Bay and Gippsland Lakes. 

Per-and polyfluoroalkyl substances, known as PFAS, are commonly found in food packaging, firefighting foam and non-stick cookware.

The group of chemicals is known for not breaking down, with long-term exposure sometimes leading to health problems.

On average, the dolphins had a concentration of PFAS chemicals 10 times higher than the amount that would normally result in liver toxicity and other health issues.

One Burrunan dolphin in Port Phillip Bay had a record PFAS liver concentration of 19,500 nanograms per gram, which was almost 30 per cent higher than any other dolphin recorded globally.

Chantel Foord says more studies need to be done to determine the effect PFAS has on dolphins.(Supplied: RMIT University)

The study’s lead and RMIT PhD researcher Chantel Foord said the results were concerning and globally significant.

“We need to understand where these compounds are coming from, where exactly are these sources into the environment, and how are they behaving,” Ms Foord said.

“The concern is that these are a critically endangered species and we don’t know enough about what sort of impacts these might be having on wonderful populations.”

Effect on humans

Ms Foord said the first step of the study was to determine the concentrations of PFAS, and now the researchers would investigating the effects on the dolphins’ health and activity.

“We need to find out where the sources are coming from so that we can effectively manage them,” she said.

But Ms Foord said it was unlikely humans would have similar levels of PFAS chemicals to the dolphins.

Burrunan dolphin jumping out of lake.

Burrunan dolphin populations are small and at high risk of localised extinction.(Supplied: Marine Mammal Foundation)

“[Dolphins will] eat the entire fish they’re having, whereas humans will just eat the muscle tissue,” she said.

“PFAS accumulates in the liver so we’re not actually getting exposed to the same concentrations that the dolphins are.”

The previous record was in dolphins located in the Pearl River Estuary in the South China Sea. 

Source of PFAS unclear

Marine Mammal Foundation director Kate Robb said the levels of PFAS were surprising given Australia only imported the chemicals rather than manufacturing them, but it could leach into the water system through other sources.

“We would expect to see high levels of PFAS in areas where they’re being manufactured so it’s really just about trying to understand how they can work their way into things like dolphins,” Dr Robb said.

Dr Kate Robb standing on a boat on lake

Kate Robb discovered the Burrunan dolphin was its own unique species in 2011.(Supplied: Marine Mammal Foundation)

“The Gippsland Lakes is subject to higher levels of fires, we’ve had those and then we had La Niña, so the system is very dynamic.”

Dr Robb said it was important to understand whether PFAS would threaten dolphin populations and increase extinction risk.

“We’re really just on that tip of the iceberg with our understanding of what these chemicals are doing within the environment, within ourselves, and with these dolphins,” she said.

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