The discovery this spring of lead-tainted deer meat in the Midwest had an unlikely inspiration: poisoned condors in the West.
Now, months before this year's deer season, officials in several states are working to warn hunters and consumers there may be far more lead in venison than almost anyone had previously suspected.
"A lot of people point out we've been eating venison for hundreds of years that's been shot with lead bullets," said Dennis Simon, the chief of wildlife for the Minnesota Department of Natural Resources. "We don't want to alarm anybody. Hunters have to make their own choice here and we'll provide them the information."
The path to understanding lead content in game meat started in Arizona, where endangered — and fastidiously monitored — California condors were falling victim to lead poisoning from eating gutpiles hunters left behind after shooting deer.
To test whether bullet fragments might be a culprit, the Peregrine Fund (an organization working to protect birds) X-rayed deer killed with high-velocity lead bullets and found evidence of lead bullet fragmentation. In 2006, scientists published their findings in the journal Wildlife Society Bulletin.
Seeing those data, a North Dakota hunter and dermatologist named William Cornatzer wondered whether bullet fragments might be making their way into venison. In March, Cornatzer and his son, a medical student, gathered donated venison and made high-definition CT scans of the meat with the help of Dr. Edward Fogarty, a radiologist at the University of North Dakota's medical school.
They found traces of lead in 53 of the 95 packages tested.
"I was going, 'Holy crap, I've been eating this stuff,'" Cornatzer said. "I've been feeding this to my family."
For the average hunter, a trace amount of lead is unlikely to be harmful, physicians say. But children and women, especially those who may bear children, are at risk of poisoning: Their bodies process lead in the same way as calcium, with the metal eventually migrating from the blood into bones, where it becomes a neurotoxin — potentially causing developmental problems (including lowered IQ) in fetuses and young kids.
And shooting a deer with lead may taint a great deal of the animal with the poison metal.
"Regardless of whether it hits bone, the bullet fragments into sometimes hundreds of tiny, tiny pieces of lead, scattered through the animal in a much broader path than hunters typically assume," said Rick Watson, vice president of the Peregrine Fund. Hunters who believe they've diligently cut away the lead from their kills, he said, simply can't, given how miniscule many of the fragments are.
After Cornatzer's test, North Dakota health authorities pulled venison off the shelves at the donation centers.
"That was a struggle for us, really," said Stephen Pickard, an epidemiologist with the North Dakota Department of Health. "But ultimately we decided that if it were any other meat, we would have called it adulterated and pulled it, so why should it be any different for this?"
As word spread of the possible contamination, other states followed with studies of their own. Minnesota's Department of Agriculture ran two tests on processed venison; the second, which examined 1,239 samples from 39 processors, found lead in about a fifth of them, and almost 90 percent of the processors had some contaminated meat. Ground venison was much more likely than steaks to contain some lead.
But it wasn't all such dire news. Wisconsin's Department of Health found much lower incidence of lead in food bank venison — about 4 percent. Since 1992, Iowa's Department of Public Health has collected lead data when Iowans get blood tests, none of it correlating a connection between consumption of deer meat and dangerous lead levels, officials there say.
The Centers for Disease Control and Prevention have launched a study of North Dakotans' blood lead levels to check against deer consumption. Last week wildlife, agriculture and health officials from seven Midwestern states convened in Minnesota to discuss how best to approach the potential health threat.
State agencies have distributed a list of recommendations for hunters, consumers and processors. (View it here.) The highlights for hunters rely on common sense: Consider using copper bullets instead of lead; take clean shots; trim well away from the wound channel.
"We don't want to damage hunting," Pickard said. "This is a great industry for this state. But at the same time, we want to tell the truth. I don't see it as a regulatory issue, as much as an issue that hunters dang sure know what's going on."
The completed studies' implications, however, are far-reaching. "Here it's probably going to be more moose and caribou, we hadn't even had it as a risk factor to ask people about it, and now we're asking," said Lori Verbrugge, a toxicologist with the Alaska Division of Public Health. "We're asking to see whether this is going on in Alaska."
As in several states and countries, Alaska outlaws lead shot in hunting aquatic birds, and some hunters are concerned this latest round of worries will threaten legal lead.
Though that would leave bowhunting or copper rounds as viable alternatives, the fallout has some hunters and manufacturers worried governments might ban lead bullets in big game hunting, as California legislators did last year, citing contamination concerns. Even Utah-based Barnes Bullets, a producer of copper ammunition, wouldn't support ban legislation.
"There's a lot of people who are supporting this, there are some people who are strictly anti-gun, anti-hunting," said Tim Janzen, an engineer at Barnes Bullets. "They see it as a way of hammering another nail in the coffin, and we're very much opposed to that. We're opposed to these kneejerk reactions that force people to change their ways."
Watson, of the Peregrine Fund, points out the issue may not call for regulation: A voluntary program in Arizona — in which hunters have traded lead rounds for copper, or agreed to dispose of lead-affected offal piles — has been a success in keeping lead out of the mouths of condors, he said.
Reached in Gilbert, Ariz., elk hunter Robert Hoskins said the program has been well-received among his fellow hunters.
"As far as the animal population's concerned, I think [switching to copper] is a good thing," said president of the Arizona Hunting Club. "Why would they recall several billion toys from China? It's poisonous to anything that eats it, it's poisonous to me and you.
"I'm not pro- having government control on my guns or anything else," he continued. "But I think going to copper makes sense for the whole animal food chain. Lead is lead. It's bad."