Pacific ocean a ‘forever chemical’ hotspot for whales
Dolphins and whales in the Pacific Ocean are contaminated with some of the highest levels of so-called persistent chemicals in the world.
The first-ever global mapping of per- and poly-fluoroalkyl substances, or PFAS, in toothed marine mammals shows leaching levels have increased over the past two decades.
Australian researchers behind the study say more intense industrial activity and PFAS production in Asian countries may be behind the increases detected in the Pacific.
In contrast, marine mammals found in the Mediterranean returned lower PFAS values; This was potentially a reflection of less industry and the European Union’s bans on various compounds.
PFAS are a group of approximately 15,000 toxic, synthetic chemicals known for their resistance to heat, stains, and oil.
These substances, found in some nonstick cookware and firefighting foam, are known as “forever chemicals” because they do not break down naturally and have been found to accumulate in the environment, including in the bodies of humans and other animals.
While the science around PFAS is evolving, the evidence is now fairly solid that they can suppress immune systems and alter hormone levels in mammals.
Marine animals are not protected when chemicals leak into waterways from homes and factories, and these substances are confirmed in bottlenose dolphin milk.
Predators that eat other contaminated animals, including toothed whales, tend to accumulate chemicals more quickly than species lower down the food chain.
University of Wollongong principal investigator and biological sciences lecturer Katharina Peters said there was more to learn about the specific health problems caused by toothed whales, but early signs were worrying.
Impaired immune systems and fertility were of particular concern for long-lived species with small populations, combined with threats such as web entanglement and climate change that needed to be overcome.
“There’s no way the population can make up for this,” Dr Peters told AAP.
“It’s not like a mouse giving birth to dozens of babies a year.”
The study, published in the Marine Pollution Bulletin, was based on more than 700 liver samples collected from stranded toothed whale species over 23 years, some new and others compiled from previous research.
Although gaps in the dataset remain, it represents the most comprehensive global mapping project yet to understand the PFAS burden across different toothed whale species and locations.
Widespread, long-lived and at the top of the food chain, toothed whales serve as a useful indicator of overall ocean pollution patterns and highlight areas most in need of further monitoring and research.
“There is a geography to pollution,” said study co-author Frederik Saltre of the University of Technology Sydney.
“Strong differences between ocean regions and toothed whale groups suggest that PFAS exposure is shaped by the intersection of human activities, regional pollution histories, and species ecology.”
Dr Peters said environmental levels would continue to accumulate until the chemicals were completely phased out and alternatives were explored.
Even if there was an immediate global ban, PFAS would remain a persistent problem and there would be no viable option to clean it up.
“It would be a bit like trying to clean a house full of glitter.”
Public awareness and scrutiny of forever chemicals is growing in Australia due to historic firefighting foam pollution, but the regulatory response has so far lagged behind Europe.
