Chemicals present in a long list of household products have made their way into British Columbia’s sea otters, according to recent research.
Analyzing the livers and skeletal muscles from 11 dead sea otters recovered from along the B.C. coast, a recent study found eight of the 40 samples tested detected per- and polyfluoroalkyl substances (PFAS). The research, published in the academic journal Environmental Toxicology and Chemistry, identified PFAS in B.C. sea otters for the first time.
Commonly known as ‘forever’ chemicals for the long time it takes for them to break down in the environment, PFAS are the human-made contents found in many common household products, such as lubricants, repellants, food packaging materials, drugs, medical devices, cosmetics, pesticides, textiles, vehicles, and electronics, as well as certain firefighting foams.
“The main question that prompted this research was the lack of data about these emerging forever chemicals on the BC coast,” said study author Dr. Juan José Alava, an adjunct professor at Simon Fraser University. “There have been several similar studies on marine mammals in the USA, but not in B.C.”
With limited information on the distribution of these chemicals across the Pacific northwest, this study aimed to gather baseline data to assess the potential impacts on sea otters in the region.
PFAS are widely found in the natural environment worldwide, including in B.C.’s orcas. The chemicals have been linked to serious health issues in humans, and PFAS are also known to cause immunotoxicity, organ damage, endocrine disruption, and reproductive impairments in wildlife such as sea otters.
A keystone species on the B.C. coast, sea otters were almost hunted to extinction during the fur trade in the 1700s and 1800s, before which hundreds of thousands of the animals ranged from Baja, Mexico to Alaska. In the 1960s and 1970s scientists began working to build back their populations. Sea otters were re-introduced to B.C. between 1969 and 1972, with 89 sea otters released into Checleset Bay on the northwest coast of Vancouver Island.
Today, B.C.'s sea otter population is estimated to be around 4,000 individuals, found mainly on the west coast of Vancouver Island from Barkley Sound to the Island’s northern tip, and in parts of the central mainland coast. This research on the accumulated chemicals now sheds light onto the health threats faced by these recovering sea otter populations.
Seven of the 11 dead sea otters studied were recovered from the coasts of Vancouver Island, including four from the Tofino and Ucluelet area, one from Nootka Island, and two from further south around Cape Beale and Port Renfrew.
“In many cases, these dead sea otters were found by indigenous communities,” said Alava.
Once reported to DFO (Fisheries and Oceans Canada), the federal department worked with the coastal communities to recover the sea otters for research. After DFO had recovered the sea otters’ tissue for study, the pelts were returned to the coastal communities, said Alava.
Sea otters have a famously high-consumption diet, eating about a quarter of their body weight every day. They are also long-living, typically for 10 to 20 years in the wild, and as such, they are particularly vulnerable to bioaccumulation of toxic pollutants over time.
“Sea otters are special because they eat similar seafood to First Nations communities around Vancouver Island and central coast,” said Alava. “So, we can use the sea otters as a sentinel ‘canary in the coal mine’ to tell us whether these pollutants are contaminating the food web. The implications for food security are very important.”
The researchers discovered that concentrations of PFAS were an average of three times higher in the dead sea otters found near urban centres and shipping routes, such as Victoria and Tofino.
“There is a proximity relation to the sources in play here, whether from runoff, landfills or in the air: being nearer to the PFAS sources makes a difference,” said the study’s first author Dana Price, a masters student in the UBC Institute for the Oceans and Fisheries.
Although the concentrations of PFAS in the sampled sea otters weren’t high enough for immediate concerns, the study highlights how these contaminants may affect general sea otter health, said Price. In particular, polycyclic aromatic hydrocarbons (PAHs) were found to be present in all the sampled sea otters, with the likely source being vehicle oil. With the study capturing a snapshot for PAH concentrations in sea otters, this information could be useful for measuring chemical pollutants in coastal ecosystems if there were ever a catastrophic oil spill.
“Now that we have a baseline for PFAS levels in local sea otters, we can monitor for any changes, including potential new sources of pollution, or any positive effects of regulation,” said Price.
Laws concerning the manufacturing of PFAS are key to preventing their further spread in nature, said Alava.
“This research can help decision makers at provincial and federal levels,” he said. “Although the Canadian government has banned the manufacture of some PFAS, the reality is there are still over 15,000 PFAS on the market. So it is important to look for more environmentally friendly alternatives.”
Potential future research in this area could include investigating other contaminants in B.C. sea otters, and ongoing monitoring of sea otter health.
“Right now we are just focusing on marine mammals, but we may look at other predators also eating seafood diets, for example, coastal wolves. These food systems have been relied on by coastal indigenous communities for thousands of years, so it still needs to be studied more, ” said Alava.
“Our world is changing, our oceans are changing, and human-made climate change is amplifying these chemicals,” continued the researcher. “We need to combat plastic pollution, and we need decisions at government levels to really reduce the extraction of fossil fuels. We need a more holistic approach, to attack the problems from the roots.”
