Levels of some of the most dangerous Pfas compounds have fallen dramatically in Canadian seabird eggs, and the authors of a new peer-reviewed study say this shows how effective regulations are.
Researchers examined Pfas levels in the eggs of northern boobies in the St. Lawrence Seaway watershed over a 55-year period. Pfas levels rose sharply from the 1960s to the peak of chemical use in the late 1990s and early 20s, and then declined.
This fall coincides with several moves by chemical giant 3M, one of the largest producers of Pfas, to move away from Pfos, one of the most common and toxic compounds, in the face of regulatory scrutiny. By 2015, major chemical manufacturers reached an agreement with the U.S. Environmental Protection Agency to phase out the similarly problematic compounds Pfos and Pfoa.
Co-author and ecotoxicologist Raphael Lavoie of Environment and Climate Change Canada called the findings “good news.”
“We see that the concentrations rise incredibly to a peak where we think they’re above the toxicological threshold for these birds, and then they decline in a really nice way,” Lavoie said. “Regulations are having a positive impact.”
PFA is one of at least 16,000 chemicals commonly used to make products resistant to water, dirt, and heat. These are called “forever chemicals” because they don’t break down naturally and are linked to a variety of health problems, including cancer, thyroid disease, kidney problems, and weakened immune systems.
The eggs were collected from remote Bonaventure Island, home to North America’s largest colony of northern gannets. Data shows that Pfos levels have fallen by 74% from peak levels of 100 ppb in eggs to levels of 26 ppb by 2024. Pfoa levels have decreased by approximately 40% over this period, but have increased again in recent years.
Meanwhile, PFHxS, another common toxic Pfas compound, decreased from 0.69 ppb to 0.19 ppb (about 72%).
This paper details how Pfas production exploded from 1969 to the mid-1990s, with a wide variety of applications and different manufacturing processes, from firefighting foams to antifouling materials. With virtually no regulatory oversight, the chemicals rapidly accumulated in the environment, exposing wildlife like the northern gannet. The St. Lawrence River was polluted by Upper Midwest manufacturing centers around the Great Lakes, and the birds were at high risk. Lavoie said the chemicals in the eggs had reached levels suggesting an ecotoxicological risk.
Around this time, the dangers of the most commonly used PFAs began to gain attention, and the United States, Europe, and Canada each increased regulatory pressure with proposed regulations and risk responses. The United Nations has similarly targeted Pfos, and the compound was listed in the 2009 Stockholm Convention, which requires signatory countries to restrict its production and use. In recent decades, water pollution has decreased significantly as the military and other firefighting foam users have switched to Pfas-free products and stopped using the chemical during training.
However, it’s not all good news. Chemical manufacturers have moved to a new generation of small PFAs, which also pose risks to the environment and wildlife. Levels of these compounds are likely elevated, and the study found an example of a change, but Lavoie said the new Pfas is more difficult to measure in bird eggs because it doesn’t accumulate as much in wild animals.
Additionally, because compounds like Pfos persist in the environment and in animals for decades, birds and the environment will remain contaminated for the foreseeable future, the authors write, “underscoring the importance of maintaining scientific and regulatory vigilance.”
