On Bonaventure Island in the St. Lawrence Seaway basin, northern gannet eggs tell a 55-year story of chemical poisoning and recovery. Once laden with PFOS—a forever chemical that accumulates in birds' bodies and doesn't break down naturally—those eggs now carry dramatically lower levels of the toxic compound. The proof is stark: PFOS concentrations that peaked at 100 parts per billion in the eggs have plummeted to 26 parts per billion by 2024, a 74 percent decline that mirrors one of the most successful environmental regulatory efforts of recent decades.
This isn't a story about nature healing itself. It's a story about governments and institutions making deliberate choices, and then following through. By the early 2000s, chemical giant 3M—one of the world's largest PFAS producers—began phasing out PFOS under regulatory pressure. In 2015, major manufacturers reached a formal agreement with the U.S. Environmental Protection Agency to eliminate both PFOS and PFOA entirely. The United Nations had already moved independently: PFOS was listed under the 2009 Stockholm Convention, which legally requires member countries to restrict and reduce its production and use. The timeline of the decline matches these interventions almost perfectly.
The gannets of Bonaventure Island were canaries in a poisoned cage. The St. Lawrence Seaway collects industrial runoff from manufacturing centers across the entire Great Lakes region, and by the late 1990s, PFAS had accumulated in the birds' eggs at concentrations that posed genuine, measurable toxicological risk. PFHxS, another major PFAS compound, fell from 0.69 to 0.19 parts per billion—a 72 percent reduction that underscores how far the regulatory arc has bent. "We see this incredible rise to a peak where concentrations seem to be higher than toxicological threshold for those birds, then it really decreases in a nice way," says Raphael Lavoie, an ecotoxicologist with Environment and Climate Change Canada and a co-author of the peer-reviewed study published in the Journal of Applied Toxicology. "The regulations are having a good effect."
A critical reason for the decline came from an unexpected source: militaries stopped using PFAS-laden firefighting foam in training. Those foams had been a major vector for chemical runoff into waterways. When military and other heavy users switched to PFAS-free alternatives—or simply stopped using the chemicals altogether—a significant fountain of contamination dried up.
But the story carries important cautions. PFOA, another dangerous PFAS compound, has declined only about 40 percent overall and has edged back up in recent years, a sign that progress can reverse. More troubling still: when regulations squeezed the most problematic PFAS compounds, chemical manufacturers simply pivoted to a newer generation of smaller ones. These carry their own risks but are harder to detect in wildlife because they don't accumulate in tissue the same way. The study found early evidence of this shift, suggesting that what isn't measured may already be rising.
PFAS compounds number at least 16,000 and are used everywhere—water-resistant fabrics, nonstick cookware, food packaging, dental floss. They're called forever chemicals because they never break down naturally, and they persist in the environment and animals' bodies for decades. They're linked to cancer, thyroid disease, kidney problems, and immune disruption.
The 55-year gannet record is unusual precisely because it captures the full arc: buildup, peak, and decline. The 74 percent drop in PFOS is real, but it didn't happen on its own. It happened because of bans, phase-outs, international agreements, and institutional purchasing decisions. The challenge ahead is whether governments and manufacturers will move with the same urgency on the replacement chemicals—before those accumulation curves get 55 years to tell their own cautionary tale.