Every Bird Matters
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Posts Tagged ‘Lead’

July 17, 2008

Getting the lead out: Birds still affected

The long-term affects of lead on birds and other animals is still leaving its mark. In a recent study released by the US Geological Survey, the evidence of lead fragments from ammunition is still wide spread. See the radiograph (right photo) in which an immature bald eagle shows numerous lead shot in its digestive tract.

The report is called “Lead Shot and Sinkers: Weighty Implications for Fish and Wildlife Health.” Here’s an excerpt:

“Science is replete with evidence that ingestion of spent ammunition and fishing tackle can kill birds,” Rattner said. “The magnitude of poisoning in some species such as waterfowl, eagles, California condors, swans and loons, is daunting. For this reason, on July 1, 2008, the state of California put restrictions on the use of lead ammunition in parts of the range of the endangered California condor because the element poses such a threat to this endangered species.” Lead poisoning causes behavioral, physiological, and biochemical effects, and often death. The rate of mortality is high enough to affect the populations of some wildlife species. Although fish ingest sinkers, jigs, and hooks, mortality in fish seems to be related to injury, blood loss, exposure to air and exhaustion rather than the lead toxicity that affects warm-blooded species.

Although lead from spent ammunition and lost fishing tackle is not readily released into aquatic and terrestrial systems, under some environmental conditions it can slowly dissolve and enter groundwater, making it potentially hazardous for plants, animals, and perhaps even people if it enters water bodies or is taken up in plant roots. For example, said Rattner, dissolved lead can result in lead contamination in groundwater near some shooting ranges and at heavily hunted sites, particularly those hunted year after year.

Research on lead poisoning related to spent ammunition and lost fishing tackle has been focused on bird species, with at least two studies indicating that the ban on the use of lead shot for hunting waterfowl in North America has been successful in reducing lead exposure in waterfowl, the report said. The authors found that upland game — such as doves and quail — and scavenging birds — such as vultures and eagles — continue to be exposed to lead shot, putting some populations (condors in particular) at risk of lead poisoning.

Read the full report on the USGS website