A new study by scientists at the University of California, Santa Cruz, has found that baby "gooney birds" are eating lead-based paint chips from buildings around the island, which ironically has been designated a National Wildlife Refuge. The results are representative of a larger problem on old military bases around the world that are being turned into wildlife habitats, the researchers say.
The findings are scheduled to appear in the August 1 edition of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world's largest scientific society.
Midway Atoll, a sliver of islands 1,200 miles northwest of Hawaii, was the site of one of World War II's biggest naval battles — the Battle of Midway, June 4-7, 1942 — and was the location of a U.S. Naval Air Facility until it was closed in the mid 1990s. The decommissioned military base, which was designated a National Wildlife Refuge in 1988, is home to the world's largest breeding population of Laysan albatrosses, or "gooney birds," so-named for their awkward crash landings.
A 1994 study showed that 85 percent of the buildings on Midway contained lead-based paint. Scientists have named lead poisoning as one of the leading causes of mortality in chicks on Midway in recent years, and there have been many reports of peripheral neuropathy, or "droopwing." "Peripheral neuropathy is a classic symptom of very high lead exposure in many species, including humans," says Myra Finkelstein, a Ph.D. candidate in environmental toxicology at U.C. Santa Cruz and lead author of the paper.
Between 1994-1997, the Navy spent millions of dollars cleaning up the island, scraping lead-based paint from buildings and repainting with oil-based paint. But the new study suggests the lead problem still exists.
"All of the droopwing chicks I sampled had severe lead poisoning," Finkelstein says. "We determined that Laysan albatross chicks continue to be exposed to lethal levels of lead from the ingestion of lead-based paint from multiple buildings on the island."
Scientists disagree about the source of lead in the blood of albatross chicks, as well as the route of exposure. Some propose that birds ingest lead indirectly by exposure to contaminated soil, which is an important pathway for lead-poisoned children in the United States. Other researchers have found birds with a type of droopwing that was attributable to malnutrition, not lead poisoning.
But the chicks that Finkelstein and her colleagues studied were poisoned by picking at paint directly from buildings or by eating paint chips that had fallen in and around their nests, the researchers report.
To determine the route of exposure, they used lead isotopic analysis, a technique that measures isotopes, or chemical markers, within various samples to trace their specific origin.
The lead isotopes in the chicks' blood matched the isotopes in lead taken from paint on the buildings, verifying the source of the lead. There was disagreement, however, between the blood isotopes and isotopes from soil surrounding the nests, ruling out soil-contamination as a route of exposure.
The researchers identified a total of 26 droopwing chicks around three buildings with deteriorated lead-based paint. Given that there are more than 200 buildings on Midway that potentially have lead contamination, the number of poisoned birds could be substantial. People on the island could also be at risk of lead poisoning, Finkelstein says — especially children, because of their hand-to-mouth behavior.
"The Laysan albatross is currently not listed as threatened," Finkelstein says. However, "The last population estimate of breeding Laysan albatrosses from the Fish and Wildlife Service showed approximately a 30 percent decline in the northwest Hawaiian Islands between the years of 1992-2001."
Many U.S. military bases around the world are being decommissioned and turned into wildlife refuges, so the problem could be more widespread than thought. "Any base painted before the 1970s most likely has lead-based paint," Finkelstein says. She is aware of at least two such bases: Johnston Atoll and French Frigate Shoals, another island in the Hawaiian Archipelago.
The U.S. Environmental Protection Agency, the University of California Toxic Substance and Research Program, and the Switzer Environmental Fellowship Program funded this research.
— Jason Gorss
(EDITOR'S NOTE — Photographs of droopwing albatross chicks are available upon request.)The online version of the research paper cited above was initially published June 21 on the journal's Web site. Journalists can arrange access to this site by sending an e-mail to newsroom@acs.org or calling the contact person for this release.
Journal
Environmental Science & Technology