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Report finds contaminants in loon eggs

  • A loon swims with chicks on its back in July 2020. The Loon Preservation Committee has found contaminents in loon eggs across the state of New Hampshire. (Raymond Hennessy photograph) Raymond Hennessy photograph

Valley News Staff Writer
Published: 11/23/2021 8:48:40 PM
Modified: 11/23/2021 8:48:36 PM

A new report released Tuesday indicates that toxic contaminants could be working their way up the food chain in several New Hampshire lakes.

The Loon Preservation Committee found significant levels of a range of hard-to-detect toxic chemicals in failed loon eggs, including at Squam Lake, Lake Sunapee, Pleasant Lake and Grafton Pond, according to its report.

“It’s no surprise that we found contaminants, but the levels were surprising,” Harry Vogel, a senior biologist at the nonprofit, said on Tuesday.

The LPC tested 81 failed loon eggs collected from 24 New Hampshire lakes over the last 10 years. Sixty percent had levels of contaminants “documented to cause negative health or reproductive effects in other bird species,” according to the report.

These contaminants “magnify” as they move up the food chain. When a loon, for example, eats a fish that has consumed hundreds of bugs that fed on contaminated sediment on a lake bottom, the loon will have heightened concentrations of the contaminant that may endanger its health. A contaminant can be present in a fish high on the food chain at a concentration “a million times” higher than its concentration in the water, Vogel said.

“In the water they are present in minute quantities,” he said. The human health concern is with consuming fish, not swimming or wading, he said.

The LPC tested for a range of common contaminants, including PFAS, an “emerging” contaminant widely used as a stain and fire repellent; PCBs, which was once widely used in electrical equipment; and pesticides including DDT.

“One of the issues is that once they’re in our environments, especially in sediments, lake bottoms, they stay,” Vogel said. “The best way to keep them out of our lakes is to never let them in there.” Nature struggles to break down “forever chemicals” like PFAS and PCBs, so they remain in the environment decades after the first contamination.

The results are a cause for concern for both loons and the broader lake ecosystems. Loons are hard to keep in captivity, so studying the effects of contaminants on their health in a laboratory setting is difficult, Vogel said. Still, the LPC found levels high enough to be a concern for other bird species.

“Loons are facing multiple co-occurring stressors,” Vogel said. “In many cases, there are many contaminants impacting them at the same time — and then lead fishing tackle, climate change. … The sum total of all of these stressors is that they’re reducing the reproductive success and health of loons in New Hampshire.”

But loons are also an indicator species that offer a snapshot into the health of a lake. They return to the same lakes year after year, and they can live as long as 25 years. If they have high levels of contaminants, then other wildlife species are also likely at risk.

The majority of the eggs sampled came from Squam Lake, near the Grafton County town of Holderness.

The LPC found high concentrations of PCBs and polybrominated diphenyl ethers, a class of flame retardants better known as BDEs. Their source remains a mystery.

“These numbers are high enough to be of concern, but also low enough that you have to be careful that the cure isn’t worse than the problem,” said EB James, the director of the Squam Lakes Association. Replacing the lake bottom, for example, would be too drastic and likely do more harm than good, he said.

The lake association is already looking into what it can do to limit contamination throughout the watershed to limit nutrient levels in the lake.

The New Hampshire Department of Environmental Services tested fish in Squam Lake after the LPC’s data came to light. Its results corroborated the committee’s findings, and it has advised anglers not to consume any yellow perch or smallmouth bass. Both of these fish are high on the food chain and had concentrations of cancerous contaminants high enough to endanger human health.

“Now that they have the fish consumption advisories, we’re protected,” James said. “The water is not the problem. It’s the sediment and then up the food chain.”

The LPC opened its report with a call for more state-led testing, and New Hampshire plans to test more fish for contaminants, said Ted Diers at the state Department of Environmental Services. However, cost is a barrier. The LPC spent $3,000 to test each individual egg, and the state paid a contractor “a few hundred thousand dollars” to test fish in 14 southern New Hampshire lakes for PFAS, Diers said.

“They’re testing to the small parts per trillion,” Diers said. “It’s very, very expensive.”

“Our waters are generally really clean,” he added. “Yes, there are some of these high levels here and there. In general, we have extremely good water quality in New Hampshire.”

Claire Potter is a Report for America corps member. She can be reached at or 603-727- 3242.

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