A THREAT TO WILDLIFE
‘These are chemical contaminants’ biologist says of PCBS
HOLDERNESS, N.H. – Navigating her boat toward a wooden platform floating in an idyllic New Hampshire lake where “On Golden Pond” was filmed, biologist Tiffany Grade spotted what she had feared.
An olive brown loon’s egg with black speckles was sitting on an nest, abandoned by its parents and with no chance to hatch. Gently scooping it up with gloved hands, Grade placed the egg in a zip lock bag and packed it into a cooler.
The egg was sent to a lab in Canada to test for chemicals including Polychlorinated biphenyls, or PCBS, that have been found in other Squam Lake loon eggs, the fish there and a tributary of the lake.
Grade is investigating the potential link between PCBS and population declines of the fish-eating birds known for their sharp beaks, black and white speckled backs, iridescent greenish heads and haunting calls.
“These are chemical contaminants,” said Grade, who works for the Loon Preservation Committee in New Hampshire. “We don’t know what the effects are but some of those eggs are at levels that have exceeded (those) known to cause health and reproductive problems in other bird species … That is enough to make us worried and dig into it more.”
The presence of PCBS on a lake in the shadow of the White Mountains demonstrates how these heat-resistant chemicals once used widely in electrical equipment and other industrial applications continue to pose a threat to wildlife more than four decades after being banned in the United States.
PCBS, a class of more than 200 chemicals used for almost 50 years, have been found in wildlife around the world, such as Icelandic killer whales, shorebirds along the Great Lakes and bottlenose dolphins along the East Coast and in the Mediterranean. Scientists have found they can make some animals more vulnerable to diseases including cancer and can disrupt growth, energy production and reproduction.
“There is five decades of research showing that PCBS have had health impacts on both wildlife and humans,” said Keith Grasman, a biology professor at Calvin University in Michigan who has studied pollutant impacts on birds in the Great Lakes and other places. “While their concentrations in the environment have declined in many situations … we still see issues with these legacy compounds.”
In New York, researchers found chickadees and song sparrows that ate insects contaminated with PCBS along the Hudson River sounded a bit different than ones in uncontaminated areas in the Adirondacks. Cornell University researchers believe the PCBS interfere with development in part of the bird’s brain responsible for song and could have consequences for breeding. PCBS continue to move up the food chain, with animals at the top often harboring the highest concentrations.
The Marine Mammal Center responds to 800 stranded marine mammals yearly along 600 miles of California coast. A 2020 study of stranded adult sea lions concluded that PCBS and DDT, which also was banned decades ago, are contributing to cancer rates as high as 23%.