Toxic chemicals in the bodies of killer whales

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Researchers analyzed muscle and liver samples from six southern resident killer whales and six Bigg's killer whales. (Archive photo)

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A study led by the University of British Columbia (UBC) found the presence of toxic chemicals in samples of muscle and liver from x27;killer whales. They would come from oil spills and smoke from forest fires.

These observations are the result of a study (New window)( in English) published Tuesday in Scientific Reports. This is the first time polycyclic aromatic hydrocarbons (PAHs) have been detected in killer whales off the coast of British Columbia.

The study also shows that these chemicals are transferred from mother to fetus.

PAHs are a type of chemical found in coal, oil and gasoline. Research indicates that they are carcinogenic, mutagenic and have toxic effects on mammals, says UBC in a press release.

Their presence in the ocean comes from several sources, including oil spills, coal burning, and smoke particles from wildfires.

Killer whales are to the oceans what canaries are to coal mines. They tell us about the health of our waters, explains one of the study's authors, Dr. Juan José Alava, principal investigator of UBC's Ocean Pollution Research Unit. and assistant professor at Simon Fraser University.

Researchers analyzed muscle and liver samples from six southern resident killer whales and six more mobile Bigg's killer whales. These 12 specimens washed up in the northeast Pacific Ocean between 2006 and 2018.

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The scientists looked for 76 PAHs and found them in all samples, with half of them appearing in at least 50 percent of the samples.

No one had yet studied the presence of PAHs in killer whales in British Columbia.

However, the researchers noted that the average level of contamination found was lower than previous studies on cetaceans in the Gulf of California. On the other hand, it is almost twice as high as that found in blood samples from captive killer whales present in Icelandic waters.

The Contaminants found in Bigg's killer whales mainly come from burning coal and vegetation, as well as wildfires. In Southern Resident Killer Whales, it tends to be contaminants from oil spills and the burning of fossil fuels like gasoline.

According to the researchers, this could be due to the difference in the animals' habitat. Bigg's killer whales move around more than Southern Resident killer whales, which stay closer to more polluted urban environments around the Salish Sea.

British Columbia's coast faces pipeline development, tanker traffic, industrial effluent, wildfires, stormwater runoff and sewage, says Kiah Lee, who contributed to the 'study.

According to study co-author Dr. Stephen Raverty, assistant professor at UBC's Institute of Oceans and Fisheries, and veterinary pathologist at the Ministry of Agriculture and Agriculture. x27;Feeding British Columbia, the Southern Resident Killer Whale population is declining. The potential causes of their decline are numerous, pollution being one of them.

Paul Cottrell, Head of Marine Mammals at Fisheries and Oceans Canada, said the study presents critical information to inform approaches to managing killer whale habitats.

The source of PAHs often comes from human activity and it is important that we have baseline data on current PAH levels in killer whales in order to monitor these trends and the impacts on marine ecosystems in the future. #x27;future, he said in a press release issued Tuesday.

Ultimately, humans must reduce and eventually eliminate consumption of fossil fuels to help fight climate change and conserve marine biodiversity, says Dr. Juan José Alava.

This would also strengthen resilience and health of marine ecosystems, which would benefit communities that depend on them, such as coastal First Nations peoples, as well as future generations.

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