Lead was removed from most consumer products, like pencils and pipes, long ago.
There’s still one product where lead is used routinely — ammunition.
This final holdout is becoming more heavily regulated, however. Beginning this spring, hunters in Missouri will no longer be allowed to use lead shot in specific conservation areas across the state. State officials say the rules are meant to protect wildlife from lead poisoning.
Unlike bullets, shotgun shells are filled with small pellets — often made of lead — that scatter across a large area.
Some birds, like ducks and geese, may mistake the pellets for small stones, which they eat to help grind up their food.
“As the shot is in the gizzard of the bird, it’s slowly being ground up,” said Mike Schroer of the Missouri Department of Conservation. “So the lead is being distributed throughout their entire body.”
Eagles and other bird species may also scavenge animal remains and accidentally ingest lead shot or bullet fragments.
Lead exposure is the leading cause of death for endangered California condors, according to the U.S. Fish and Wildlife Service.
But for smaller species, like songbirds, it’s difficult to estimate how many individuals are dying from lead poisoning, said Rebecka Brasso, an ecologist at Weber State University in Utah.
“We very rarely see dead animals or even sick animals, because they tend to hide,” Brasso said. “Finding something that has died from a single contaminant, like lead, is very difficult.”
Another big question is whether lead has long-term negative effects on animal species — like changes in behavior and reproduction.
In one lab study, female pigeons that ate a single 95-milligram lead pellet laid smaller eggs and had smaller babies than pigeons that were not exposed to lead.
For reference, a U.S. penny weighs about the same as 25 of those lead pellets.
Few studies have tried to measure how lead is affecting birds in the wild, said Brasso, in part because it’s very difficult and expensive to do.
Brasso recently led a three-year study in the Southeast Missouri Lead District — once one of the largest lead mining operations in the world — to understand how lead contamination affects songbird reproduction.
“We had six or seven people working 14-hour days for three months at a time to follow the reproductive success of these songbirds,” she said. “The manpower required to gather that data is immense.”
‘Protecting hunting heritage’
The regulation of lead shot is not new.
Under federal law, waterfowl hunters have been required to use nontoxic, lead-free shot since 1991.
In Missouri, lead shot has been banned from specific conservation areas for years, including Columbia Bottom in north St. Louis County.
Last August, the Missouri Department of Conservation added 16 conservation areas where hunters must use nontoxic shot — bringing the total number to 37. The new regulations went into effect March 1, ahead of the spring turkey season.
But some hunters have been reluctant to give up their lead shot.
Schroer said hunters have cited a range of reasons why they prefer to use lead shot, from the perceived ineffectiveness of nontoxic alternatives to stockpiles of lead shot that they want to use.
“This is not an anti-hunting thing,” Schroer said. “It’s about protecting hunting heritage for the long-term. We can’t continue to put something on the landscape that’s toxic and leave that for the generations to come behind us.”
A complete list of approved nontoxic shot, as well as restricted conservation areas, can be found on the Missouri Department of Conservation website.
Follow Shahla on Twitter: @shahlafarzan
Send questions and comments about this story to email@example.com