Condor lead poisoning persists, impeding recovery, says CU-UCSC study

June 25, 2012

The California condor is chronically endangered by lead exposure from ammunition and requires ongoing human intervention for population stability and growth, according to a new study led by the University of California, Santa Cruz, and involving the University of Colorado Boulder.

Since 1982, the condor population has increased from 22 to approximately 400, but only through intensive management including captive breeding, monitoring and veterinary care. The bird's recovery has been deceptively successful as its primary threat -- poisoning from lead-based bullets ingested as fragments from carrion -- has gone largely unmitigated, according to the study.

"We will never have a self-sustaining wild condor population if we don't solve this problem," said lead author Myra Finkelstein, a research toxicologist at UC Santa Cruz. "Currently, California condors are tagged and monitored, trapped twice a year for blood tests and when necessary treated for lead poisoning in veterinary hospitals, and they still die from lead poisoning on a regular basis."

The California condor, which once numbered in the thousands in the western United States and Mexico, is the largest land bird in North America.

Reintroductions since the bird's near extinction in 1982 have led to free-flying populations in Arizona, California and Baja California. Dubbed "thunderbird" by American Indians, its impressive wings can span more than 9 feet. A type of vulture, the creature's bald head allows feeding without the mess of carcass flesh sticking to its plumage.

The study, published this week in Proceedings of the National Academy of Sciences, shows that annually from 1997 to 2010, 20 percent of the California condors sampled suffered lead poisoning and needed chelation therapy, a metal detoxification process that also is used for children with lead poisoning. Cumulatively over the time period, nearly half of the population tested was poisoned by lead, with many birds suffering repeat poisoning within and across years.

"Lead exposure and poisoning levels in condors continue to be epidemic," said co-author Dan Doak, a new endowed chair and professor in CU-Boulder's Environmental Studies Program. "Despite the current efforts to help the species, the wild population will decline again toward extinction in a few decades unless these unsustainable and very expensive efforts continue in perpetuity."

From 1997 to 2010, the annual prevalence of lead exposure -- with blood lead levels indicating potentially serious but nonlethal effects -- ranged from 50 to 88 percent in California condors in the wild. Also, the annual median blood lead levels in free-flying California condors exceeded the average for pre-release condors bred in captivity by at least threefold.

The researchers found no evidence that a partial ban on the use of lead-based ammunition in condor habitats, enacted in California in 2008, resulted in lower incidence of lead exposure and poisoning. Although alternatives to lead-based bullets are available, regulations limiting the use of lead-based ammunition face stiff opposition from hunting organizations and gun-rights groups, according to the researchers.

The estimated cost of a multiagency condor recovery program including the U.S. Fish and Wildlife Service is about $5 million per year, according to the researchers.

"Integrating a study of the effects of toxic chemicals on individual wild animals into a modeling of whole-population impacts is very unusual," said Doak. "But the results provided a critical piece of our results in this study."
-end-
The study was supported by the National Park Service, Western National Park Association and the U.S. Fish and Wildlife Service.

A link to the PNAS paper will be posted within the news release at http://www.colorado.edu/news. For more information on CU-Boulder's Environmental Studies Program visit http://envs.colorado.edu/about/.

University of Colorado at Boulder

Related Lead Poisoning Articles from Brightsurf:

New study reveals poisoning exposures in Australian schools
New research from the University of Sydney has found poisoning exposures in children and adolescents while at school are relatively common and appear to be increasing, highlighting the need for more robust prevention measures.

Preventing lead poisoning at the source
Using a variety of public records, researchers from Case Western Reserve University examined every rental property in Cleveland from 2016-18 on factors related to the likelihood that the property could have lead-safety problems.

A better informed society can prevent lead poisoning disasters
In a paper published Sept. 8 in the Proceedings of the National Academy of Sciences, John R.

Machine learning models identify kids at risk of lead poisoning
Machine learning can help public health officials identify children most at risk of lead poisoning, enabling them to concentrate their limited resources on preventing poisonings rather than remediating homes only after a child suffers elevated blood lead levels, a new study shows.

Lead poisoning could reduce gene expression in humans
Scientists have unveiled a correlation between high blood lead levels in children and methylation of genes involved in haem synthesis and carcinogenesis, indicating a previously unknown mechanism for lead poisoning.

Inconsistent EPA regulations increase lead poisoning risk to kids, study finds
As new lead protection rules from the Environmental Protection Agency move toward finalization, research shows that tens of thousands of children are at increased risk under the current set of inconsistent standards.

Cases of poisoning: Liquids containing cannabidiols for e-cigarettes can be manipulated
The health risks of e-cigarettes have come into focus after the deaths of several 'vapers' due to lung injury in the USA recently.

New potential cause of Minamata mercury poisoning identified
One of the world's most horrific environmental disasters--the 1950 and 60s mercury poisoning in Minamata, Japan--may have been caused by a previously unstudied form of mercury discharged directly from a chemical factory, research by the University of Saskatchewan (USask) has found.

Lead poisoning reduced with safer mining practices
We report on an extremely successful and novel project to reduce lead poisoning among artisanal gold miners in Nigeria.  This report highlights the success of OK International in partnership with Doctors Without Borders to introduce safer mining practices in an area where thousands are severely lead poisoned and where hundreds of deaths have been recorded from acute poisoning.

Suicide attempts by self-poisoning have more than doubled in teens, young adults
A new study from Nationwide Children's Hospital and the Central Ohio Poison Center found rates of suicide attempts by self-poisoning among adolescents have more than doubled in the last decade in the US, and more than tripled for girls and young women.

Read More: Lead Poisoning News and Lead Poisoning Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.