Pollutants in the St. Lawrence River estuary also turn up in the bodies of the endangered beluga whales that live there. Artist Erica Gajewski represented this contamination with the chemical structures of several chemicals found in their environment. Image: Erica Gajewski
By Lucy Schroeder
Great Lakes pollutants threaten a special population of beluga whales.
Their chemical structures figure prominently in a picture artist Eric Gajewski recently drew to illustrate the plight of the mammals living in the St. Lawrence River.
“Water is such a sacred thing–that it can also be so toxic and poisonous seems to go against a life law,” said Gajewski, an environmental studies doctoral student at York University in Toronto, Ontario.
The water draining from the Great Lakes through the St. Lawrence and into the ocean contain a toxic stew that may contribute to a recent rise in the number of whales that die shortly after giving birth, scientists say.
Persistent organic pollutants–chemicals like PCB, DDT, and PBDEs that remain in the environment for years–flow out of cities around the Great Lakes and the St. Lawrence River, said Jonathan Verreault, an associate professor in the Centre de recherche en toxicologie de l’environnement at Université du Québec à Montréal.
PBDEs are flame retardants in the stuffing of mattresses and couches. They stick to fibers and come out in household water discharges or are transported through the air as vapor, Verreault said. Wastewater treatment plants can remove 30 percent to 50 percent of them, but the rest wash into the river.
That’s where they accumulate in the bodies of organisms, including the belugas which are top predators in the estuary’s food chain, said Verreault, who led a three-year study to find out what chemicals are in the whales and how they affect them.
The study is an attempt to understand why the beluga population is not recovering after years of protection. The belugas of the St. Lawrence are listed as endangered by the federal agency Fisheries and Oceans Canada.
The researchers found that PBDE levels have not significantly decreased in whale blubber in the 17 years since the fire retardant was banned. That suggests that regulations are too recent to reduce the PBDE contamination, according to a study by the group published in Environmental Research this month.
And the PBDE levels in the beluga whales in the St. Lawrence are greater than the levels observed in whales elsewhere.
St. Lawrence beluga whales are of particular interest because they are residents of the estuary. Contamination in their bodies can indicate contamination in the estuary, Verreault said.
Since PBDE was banned in Canada and restricted in parts of the United States, manufacturers have replaced it with other flame retardants. The researchers found varying levels of these emerging flame retardants in the whales’ blubber.
Chemicals are considered persistent if they resist breakdown by temperature, bacteria and UV radiation, Verreault said. When persistent pollutants are consumed by animals, they can be excreted immediately.
But, some accumulate in the animal’s body by sticking to proteins and lipids, Verreault said.
Even if their bodies can excrete the pollutants, by living in the contaminated environment the belugas are continually taking up these chemicals. It will take many years before we can see a decrease in contamination levels of the belugas, Verreault said.
The chemicals may disrupt the whale’s hormone system, which may be responsible for the particularly high death toll of calves and reproductive-age females. There is evidence for the hormone disruptive power of these flame retardants in seals and gulls.
Verreault’s team is studying if that’s the case with belugas.
The contamination may be one of many factors hindering the St. Lawrence beluga whale recovery. They are also stressed by boat noise, reduced access to food and climate change, Verreault said.
The chemicals add to these stressors, reducing the belugas’ health through subtle changes that do not immediately kill them, he said.
These are problems for not just the belugas, but for the people who depend on the Great Lakes and the St. Lawrence.
A photo of Gajewski’s artwork, “Mercury, Water, PCB, DDT,” was recently published in UnderCurrents Journal of Critical Environmental Studies. The piece emphasizes these entanglements between the beluga’s and human activity.
“I’m concerned for [the belugas] and us both–we are both at the mercy of what we are doing to the environment,” Gajewski said.
She was inspired to make the life-size drawing (108 inches by 144 inches) after visiting the belugas in an aquarium for the first time and finding their beauty and sense of intelligence breathtaking, Gajewski said.
She wanted to translate the black-and-white text of scientific papers into something that conveys the sense of awe and wonder of the belugas, as well as informs views of the whales’ plight.
One of her goals is to bear witness to the species she portrays, she said.
“It’s like something that you absolutely love just vanishing forever and so I feel compelled to bear witness to what is going on. That is my capacity–I can’t change everything singlehandedly but I can say, ‘Hey I saw this’,” Gajewski said.
Collectively, people may be able to make a difference.
“We all live in the same world, we draw lines, create boundaries–parts of the lakes belong to United States, Canada,” Gajewski said. “I’m concerned for the whales and for us. We are both at the mercy of what we are doing to the environment.”
What can the average person do to reduce the contamination?
Verreault suggests buying materials made with natural fibers, such as mattresses made with cotton, latex or polyester to be sure that they do not contain flame retardants. Vacuuming your home with a high efficiency particulate air filter is another means of reducing contamination suggested by the National Institute of Environmental Health Sciences.
“There are ways that people can make the river a safer place,” Verreault said.