Toxic chemicals found in endangered killer whales in British Columbia

A study of tissue samples from killer whales in Canada was the first to find a dangerous toxic chemical, known as 4NP, in the animals’ flesh.

A toxic chemical, used in toilet paper production, and other ‘forever chemicals’ have been found in the bodies of orcas in British Columbia. Among the orcas affected by this phenomenon are the endangered Southern Resident Killer Whales, a resident orca community in the northeast part of the North Pacific Ocean. The SRKW is listed as an endangered wildlife species on Schedule 1 of the Species at Risk Act.

Endangered whales are being affected by pollution © Thomas Lipke via Unsplash

These findings emerged from a recent study by researchers from the Ocean Pollution Research Unit of the Institute for the Oceans and Fisheries of the University of British Columbia, the department of Biology of the University of Victoria, the DFO, and SGS AXYS Analytical Services Ltd. The study, titled “Emerging Contaminants and New POPs (PFAS and HBCDD) in Endangered Southern Resident and Bigg’s (Transient) Killer Whales (Orcinus orca): In Utero Maternal Transfer and Pollution Management Implications” was published in December 2022 by the American Chemical Society.

This research is a wake-up call. Southern residents are an endangered population and it could be that contaminants are contributing to their population decline. We can’t wait to protect this species.

Dr. Juan José Alava, principal investigator of the Ocean Pollution Research Unit at the Institute for the Oceans and Fisheries (IOF)

Toxic chemicals found in British Columbia orcas

The researchers behind this study analyzed tissue samples from Southern Resident Killer whales and six Bigg’s whales stranded along the local coastline between 2006 to 2018. The goal was to investigate the concentrations of selected ‘contaminants of emerging concern‘ (CECs) and new persistent organic pollutants (POPs) in the Southern Resident and Bigg’s killer whales in the Northeastern Pacific and the in-utero transfer of these contaminants in the selected species.

Their analysis showed that these chemicals are prevalent in this group of whales. In the samples, 4-nonylphenol was one of the most pervasive chemicals, making up 46 per cent of the identified animals. 4-nonylphenol, also known as 4NP, is an organic compound utilized in pulp and paper, detergents, soap, and textile processing and it’s listed as a toxic substance in Canada. This poisonous chemical makes its way into the ocean through industrial runoffs and sewage treatment plants.

4NP makes its way into the ocean through industrial runoffs and sewage treatment plants © Abigail Lynn via Unsplash

Once it reaches the ocean, a phenomenon called biomagnification occurs. When this happens, the concentration of toxic chemicals builds up along the food chain from the smaller organisms that ingest them until it reaches apex predators like killer whales. This recent study is the first to identify the toxic chemical 4NP in killer whales. The most common substance among the so-called ‘forever chemicals,’ named so because of their persistence in the environment, found in the sampled whales was 7:3 FTCA. The researchers found that the identified chemicals transferred from mother to fetus. Ninety-five per cent of 4NP got transmitted through the womb.

What could be done about this issue? 

The halting of the production of chemicals of concern, such as 4NP and 7:3 FTCA, and the identification and addressing of potential sources of marine pollution in the area are approaches that could mitigate pollutant sources and the contamination of SRKW’s habitat.

This investigation is another example of an approach that takes into account the health of people, animals and the environment, using killer whales as a case study to better understand the potential impacts of these and other compounds to animal and ecosystem health.

Dr. Stephen Raverty, IOF adjunct professor and veterinary pathologist with the B.C. Ministry of Agriculture and Food


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