It’s been nearly 300 years since lead was first discovered in Missouri.
But the element's important role in the state's economy may come at a price to another natural resource. Scientists are planning to study the health effects of lead on local songbird populations.
The research, conducted by biologists at Southeast Missouri State University and the University of Missouri-Columbia, will take place in the Southeast Missouri Lead District, which contains the world’s largest deposits of galena, an important source of lead.
Many of the region's lead mines have closed, but contamination from previous mining operations remains. Songbirds, such as robins and bluebirds, have become exposed to the metal through foraging for insects and worms that live in the dirt.
Ingesting lead could hurt the birds’ ability to breed, said Rebecka Brasso, an avian toxicologist at SEMO.
“Lead is a neurotoxin, so theoretically, any sort of physiological or neurological damage in an adult bird could impact their ability to care for their young,” Brasso said. “That could change the number of offspring they produce.”
Although researchers have long studied how lead exposure affects people, there has been little scientific research done on the effects of lead on songbirds and other wildlife. Brasso said it’s unknown what concentrations of the metal could be harmful to them.
Next month, she and her colleagues plan to set out nest boxes to collect birds for the study, then examine levels of lead in their blood and track the number and the health of their offspring. They will compare birds that live in contaminated areas to birds that don’t.
Brasso hypothesizes that birds with higher lead concentrations reproduce less successfully.
Songbirds overall have been declining in the United States for several decades. Brasso said they serve a significant role in the environment.
“A lot of songbirds eat insects throughout the entire summer, so they play a really significant role in maintaining insect populations,” she said. “If we lose them, who’s to say what could be the ramifications of that?”
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