July 7, 2003
Study shows lead-based paint is poisoning albatross
chicks
Danger continues at Midway Atoll National
Wildlife Refuge
By Tim Stephens
Lead-based paint from deteriorating buildings still poses a hazard to
wildlife on Midway Atoll, despite extensive environmental remediation
efforts undertaken as part of the conversion of the site from a military
base to a national wildlife refuge.
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Lead poisoning causes the "droopwing"
symptom seen in these Laysan albatross chicks, above and below,
at Midway Atoll National Wildlife Refuge. Droopwing
chicks are common around the buildings on Midway, where they are
exposed to lead-based paint. Photos: Bradford Keitt |
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A new study by UCSC researchers shows that Laysan albatross chicks
in nests near the buildings are suffering lead poisoning as a direct
result of eating paint chips from the soil in and around their nests.
Previous reports had documented lead poisoning in albatross chicks
nesting near buildings on Midway, but the exact source of the lead remained
unclear. The UCSC researchers used lead isotope ratios as a tracer to
identify the source of the lead in the blood of affected chicks.
"We were able to pinpoint the cause of the lead poisoning. The
chicks are eating paint chips directly--it's not from contaminated soil--and
knowing that can help guide remediation efforts," said Myra Finkelstein,
a graduate student in environmental toxicology and ocean sciences.
Finkelstein conducted the study with Donald Smith, professor of environmental
toxicology, and Roberto Gwiazda, a research toxicologist. Their findings
will appear in the August issue of Environmental Science & Technology
and have already been published on the journal's web site.
The lead levels in some albatross chicks on Midway are so high that
the toxic metal damages their peripheral nervous systems, leading to
a symptom known as "droopwing"--the chicks are unable to hold
their wings tucked up against their bodies, and their wings often drag
on the ground. It is a classic symptom of lead poisoning, comparable
to the "wrist drop" symptom in humans, said Smith.
"If you found this level of lead in a child, the child would be
hospitalized immediately," he said.
But Smith noted that the levels of lead in paint samples from Midway
are not unusual considering the age of the buildings. "The situation
is similar to many neighborhoods with older homes painted with lead-based
paint," he said. "What's needed is better lead-hazard control,
including building maintenance and clean-up of the site."
Lead-poisoned chicks are common around the buildings on the island,
Finkelstein said. Many chicks with lead poisoning don't have droopwing,
but likely suffer from other forms of toxicity that lower their chances
of survival, she said. Chicks with droopwing may survive as long as
their parents are feeding them, but once they reach the fledgling stage
and their parents abandon them, they are doomed to starvation because
they can't fly. Other affected chicks may die sooner from complications
of lead poisoning, Finkelstein said.
Midway hosts the largest known breeding population of Laysan albatross,
accounting for about 65 percent of the total global population. The
most recent census, in 2001, counted 287,000 breeding pairs. Many other
species of seabirds also nest on the atoll's tiny islands. The albatross
nest on the ground and have no fear of humans, so their nests are found
not only in open fields but also scattered among the buildings and beside
roads and walkways.
"It's an amazing thing to see. The birds are everywhere,"
Finkelstein said.
Finkelstein looked at albatross chicks from two sites, one near buildings
and another in an open field with no known source of lead contamination.
She collected blood samples from the chicks and soil and paint chips
from each chick's nest. All the samples were analyzed for lead levels
and isotopic composition using a highly sensitive mass spectrometer.
There are four naturally occurring isotopes of lead, and their ratios
may vary depending on the source of the lead sample. Different layers
of paint on the buildings at Midway had different isotope signatures,
and the blood samples and soil samples also varied widely in their isotope
compositions. To identify the source of exposure, the researchers had
to use a "case study" approach, looking at each chick individually
and the samples taken from its nest. They found a strong correlation
between the isotope signatures in a chick's blood and the signatures
in paint chips from its nest. There was no correlation with isotope
signatures from soil samples.
Lee Ann Woodward, a U.S. Fish and Wildlife Service contamination specialist
for the Pacific Region, said it's not hard to understand how the chicks
are ingesting paint chips.
"I call it the bored chick syndrome," she said. "They're
sitting on the nest for six months and they constantly groom the nest
and the area around it."
The Fish and Wildlife Service is taking steps to deal with the problem,
Woodward said. Although the number of chicks affected by lead poisoning
is small compared to other causes of mortality and is not a threat to
the overall population, the agency takes the issue very seriously, she
said.
"This study has been very helpful to us in pointing out the need
to do something," Woodward said. "We have gotten funding this
year to go out and determine how extensive the problem is and what it
would take to deal with it. Because it's such a remote site and any
equipment has to be sent out on barges, we really need to have a good
idea ahead of time what the scope of the operation will have to be."
Smith said the situation on Midway underscores the potential for environmental
and public health hazards on decommissioned military bases, many of
which serve as wildlife refuges. Lead-based paint is just one of many
potential hazards at these sites, he said.
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