In the serene waters off Melbourne and Gippsland, a disturbing reality is unfolding for the critically endangered Burrunan dolphins. Recent research has revealed that these dolphins are burdened with the highest concentrations of toxic PFAS chemicals ever recorded in dolphins worldwide.
The joint study, conducted by scientists from the Marine Mammal Foundation, RMIT, and Melbourne University, paints a grim picture. PFAS chemicals, infamous for their persistence in the environment, were found in alarming concentrations in the livers of these dolphins.
These chemicals, commonly found in food packaging, firefighting foam, and non-stick cookware, are often referred to as “forever chemicals” due to their resistance to breaking down.
Only 250 individual Burrunan dolphins remain in the known populations of Port Phillip Bay and Gippsland Lakes. The species is dangerously close to local extinction.
Dangerous PFAS levels found in endangered dolphins
From 38 dolphin samples collected along Victoria’s coastline, the findings were particularly dire for the Burrunan dolphins in Port Phillip Bay and Gippsland Lakes.
These dolphins exhibited PFAS levels more than ten times higher than what is known to cause liver toxicity and other severe health issues.
One juvenile Burrunan dolphin from Port Phillip Bay had a staggering PFAS liver concentration of 19,500 nanograms per gram, the highest ever recorded in a dolphin.
Chantel Foord, the lead author of the study and a joint PhD researcher with RMIT’s Ecotoxicology Research Group and the Marine Mammal Foundation, expressed deep concern over these findings.
“Not only did we find the highest levels of these man-made toxicants in a species that’s already critically endangered, but we also discovered a juvenile dolphin with PFAS concentrations almost 30% higher than any other recorded globally,” said Foord.
While these results are alarming, Foord clarified that they do not necessarily pose a direct risk to humans in Victorian waters.
Unlike dolphins, humans consume only the muscle tissue of fish, not the liver, which is where these pollutants accumulate.
The sources of PFAS in the aquatic environment are diverse, including manufacturing effluent, wastewater treatment plant discharge, urban runoff, landfill runoff, and firefighting foams used near waterways.
Despite international regulations on some of these chemicals, Australia has not fully ratified the Stockholm Convention on Persistent Organic Pollutants, allowing their continued import and use.
The groundbreaking research, published in the journal Science of the Total Environment, raises critical questions about the presence of these pollutants.
“While we would expect higher concentrations in locations where these chemicals are produced, that is not the case here,” Foord noted. “Without manufacturing in Australia, why are we seeing such alarming PFAS levels?”
This study also uncovered the presence of newer, emerging contaminants in the dolphins, indicating that replacement chemicals are already making their way through the food web.
Critically Endangered Burrunan Dolphin
The Burrunan dolphin, Tursiops australis, recognized as a distinct species in 2011 by Dr. Kate Robb, Director of the Marine Mammal Foundation and co-author of the study, is already critically endangered.
With less than 250 individuals remaining in the known populations of Port Phillip Bay (approximately 120 individuals) and Gippsland Lakes (approximately 63 individuals), the species is at high risk of local extinction.
Dr. Robb emphasized the urgency of understanding and mitigating the threats to these dolphins.
“With the current immune-compromising risks and health impacts associated with PFAS exposure, it is incredibly concerning that these Burrunan dolphins have the highest documented PFAS levels worldwide,” she said.
“Our continued research is crucial to ensuring the future of this species.”
The study, titled “Hepatic concentrations of per- and polyfluoroalkyl substances (PFAS) in dolphins from south-east Australia: Highest reported globally,” by Chantel Foord, Drew Szabo, Kate Robb, Bradley Clarke, and Dayanthi Nugegoda, is published in Science of the Total Environment (DOI: 10.1016/j.scitotenv.2023.168438).
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