BELTSVILLE, Md. (KSDK) -- About half of ground-feeding songbirds collected in a historic mining district in southeast Missouri contain elevated levels of lead, according to the U.S. Geological Survey.
Lead district sites examined included the Missouri Mines in the Old Lead Belt and Washington State Park on the Big River floodplain, said USGS spokesperson Diana Noserale.
According to Noserale, tested birds had lead concentrations exceeding those of reference birds by factors of eight in blood, 13 in liver, and 23 in kidney samples.
Lead poisoning in birds can lead to abnormal muscular function, kidney and liver failure, decreased fertility, and anemia.
Ground-feeding songbirds were used for the study because they were more likely to be exposed to lead than songbirds feeding in the shrubs or forest canopy, said Noserale. Cardinals, robins, blue jays, and eastern towhees were among the birds tested.
Southeast Missouri has a long history of lead mining and smelting dating back to 1721. According to Noserale, periodic flooding and erosion have transported lead throughout the environment.
The survey was part of a U.S. Department of the Interior investigation measuring whether wildlife might be adversely affected by exposure to lead-contaminated soil.