Bald Eagles

New Study Reveals DDT in California Condors – High Country News – Know the West

New Study Reveals DDT in California Condors - High Country News - Know the West

Chemicals spilled in the 1970s continue to seep into the food chain. But the Yurok tribe is confident that their birds will be fine.

A juvenile condor awaits release at the Yurok Tribe Condor Detention Center in late March.

Paul Robert Wolf Wilson/High Country News

A study published last week in Environmental science and technology examined the presence of DDT-related chemicals in California condors, or prey, as the Yurok call them. The toxic chemicals have proven a lasting obstacle for Native and American agencies seeking to reintroduce the giant birds to their homelands.

DDT — dichloro-diphenyl-trichloroethane — is a powerful organochlorine insecticide used in agriculture. The world’s largest DDT manufacturing plant was operated by the Montrose Chemical Corporation in Torrance, California, until the early 1980s. For more than three decades, the company dumped DDT and other chemicals on the plateau of Palos Verdes, and it is estimated half a million barrels of DDT-contaminated sludge could still be buried offshoreseeping chemicals into the water.

This proved particularly harmful to the condors’ long-term health, because DDT is a fat-coating molecule, which means it dissolves more readily in lipids than in water. So if you happen to be a blubbery sea lion, swimming in DDT-polluted water, guess where that insecticide ends up? In the belly of whatever eats your fatty carcass after you die – which could very well be a condor. And even though the Environmental Protection Agency banned DDT in 1972 and Montrose went out of business the following decade, the Superfund site it left behind keeps the chemicals circulating in coastal food chains today.

The new study, conducted by a team of researchers based in San Diego and surrounding areas, found that coastal condors are more contaminated with DDT-related compounds than inland condors, and that these levels “are factors to consider.” account in condor reintroduction efforts”.

Condor reintroduction efforts, meanwhile, are underway up north, 700 miles from the Superfund site. Tiana Williams, director of the wildlife department of the Yurok Tribe in Northern California, was not involved in the study, but she undertook a separate analysis in 2008 to determine the feasibility of reintroducing condors to the ancestral territory of the Yurok. Along with habitat conditions and lead poisoning, DDT was one of his main concerns.

Its feasibility analysis, supported by the US Fish and Wildlife Service, was encouraging. Williams said while DDT remains a problem for the central California condor herd, the chemical’s impacts decrease with distance from the Superfund site. She studied fat migrating marine animals – sea lions, gray whales, killer whales – to see if they carried DDT along the coast, and even examined harbor seals, which are non-migratory and show no signs of contamination. by DDT.

Yurok Wildlife Department Director Tiana Williams said the tribe hopes the recently released condors are far enough away from the DDT Superfund site that the chemical won’t cause the reproductive problems it is causing 700 miles away. South.

Paul Robert Wolf Wilson/High Country News

“There is a very clear downward trend in DDT as you head north. We hope there will be no breeding problems in our area,” Williams said at a press conference last March before the Yurok tribe released the first condors to fly there in more than a year. century.

Condors only produce one egg every two years, so each egg is important for repopulation. When a condor is contaminated with DDT, its egg can be malformed. “It will just look funky,” Williams said. HCN. “But it also loses what they call the surface crystalline layer.” It is the outer layer that gives the hull its hardness and integrity. The loss of this outer layer increases the egg failure rate. “They’ll either crack because they’re more brittle,” Williams said, “or they’ll just lose all their water.”

If a condor egg looks healthy, scientists sometimes remove it from the nest, replace it with a dummy egg, and incubate the real one to ensure success. Then they replace the egg in the nest when it seeds.

DDT remains a problem for other scavengers, including bald eagles, whose eggs it affects in the same way. But the eagle population in the Channel Islands, just off Torrance, has recovered significantly in recent decades. And further south, researchers from Environmental science and technology One study noticed a similar trend: they found about seven times more DDT-related compounds in fatty animals off the coast of California than in animals like sea lions in the Gulf of California in Mexico. The contamination also seems to decrease towards the south.

Williams said overall the outlook is good for the birds of the Yurok tribe. And the San Diego study acknowledges that DDT is a “sublethal” threat to condors. Yet it remains a major concern, especially in the south. “Abundance is so high in Southern California”, said Eunha Hoh of San Diego State University, one of the authors of the study. “We can’t just move on. … Our ocean is so much more polluted with DDT.

“We can’t just move on. … Our ocean is so much more polluted with DDT.

It remains to be seen what to do with it. “Put simply, it’s one of the biggest environmental threats on the West Coast,” said California Democratic Senator Dianne Feinstein last year. “It’s also one of the toughest because these barrels are 3,000 feet below the surface of the ocean and there’s not a lot of documentation on who did the spill, where exactly it happened. or how many barrels were spilled.”

Paul Robert Wolf Wilson/High Country News

Brian Oaster (they/them) is an editor at High Country News and a member of the Choctaw Nation of Oklahoma. He is an award-winning investigative journalist living in the Pacific Northwest. Email them at [email protected] or send a letter to the editor. See our Letters to Editor Policy.

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