NZ Dolphins Endangered By Unexpected Toxins

Massey University scientists say unexpected contaminants are threatening Aotearoa’s dolphins, despite government restrictions on the use of toxic substances.

In a new study in Marine Pollution Bulletin, the authors report surprising levels of toxins (per- and polyfluoroalkyl substances more commonly known as PFAS) in common dolphins examined post-mortem between 2019 and 2020.

Since late 2017, the Ministry for the Environment has been leading an all-of-Government programme to tackle PFAS within the environment and to assess the risk posed.

However, new international research led by Massey University and collaborators, highlights new insights about the prevalence of PFAS in New Zealand.  Scientists examined stranded dolphins post mortem and assessed a number of environment contaminants as part of their ongoing health and life history programme.

Professor Karen Stockin with Cetacean Ecology Research Group postgraduate students Emily Palmer and Rebecca Boys during a dolphin post mortem examination

Used since the 1950’s

PFAS are a large group of manufactured compounds that have been used since the 1950’s to make products that are resistant to heat, stains, grease and water.

Used in many different industrial and consumer applications, more than 4,000 such substances exist.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are the most studied PFAS due to their known toxicity and are now listed under the Stockholm Convention. While PFOS use in New Zealand was phased out as of 2011, some applications of PFOA have remained possible until only recently.

While of concern, the concentrations and extent of PFAS reported in the New Zealand environment from this earlier all-of-Government response suggested PFAS levels were low compared to similar sites in Australia and the United States. 

Surprise results

Massey University Professor Karen Stockin, study lead, says: “We were surprised to learn PFAS in our dolphins aligned with levels recently reported in porpoises examined off the coast of Japan and other (toxin) manufacturing countries in the past decade.

“We also note that the levels reported in New Zealand dolphins are higher than those of other indicator species recently examined during the all-of-Government response to PFAS,” she adds.

“Our findings highlight two important considerations. Firstly, the remarkable ability for marine mammals to act as sentinel indicator species, and secondly, the risk apex predators such as dolphins and humans endure due to their ability to accumulate such contaminants via the processes of bioaccumulation and biomagnification.”

Dr Louis Tremblay, an ecotoxicologist at the Cawthron Institute and the University of Auckland stated: “This study confirms the persistence of this family of fluorinated pollutants. We don’t yet know the full extent of the risk these substances pose to humans or wildlife, but it highlights the need for a better management and stewardship of persistent chemicals to minimise their unintended impacts.” 

Photo Credits: Massey University.

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