Spurred by the North Dakota findings, health departments in several other states ran similar tests and also found tainted meat. In the largest survey of donated venison, Minnesota officials X-rayed 1,239 packages and found 22 percent to be contaminated with lead.
"The lead fragments are so small that you can't feel them in your mouth when you are eating venison burger or sausage," Cornatzer said.
Because of the possible consequences for humans, North Dakota's Department of Health and the U.S. Centers for Disease Control and Prevention (CDC) are currently analyzing the blood-lead levels of 740 North Dakotans. The study participants were asked about possible sources of lead exposure—including game. The complete results are expected sometime next year. Chinaro Kennedy, a CDC epidemiologist leading the study, says "the number one thing people need to be aware of is the potential risk from lead—even in small doses."
The symptoms of low-level lead poisoning are insidious, ranging from hearing loss and high blood pressure to cardiovascular disease, stroke and kidney damage. Young children exposed to lead can suffer permanent intellectual impairment. In 2006, research conducted at Tulane University showed that blood-lead levels that were once thought safe are linked to a higher risk of death from a range of causes.
In May 2008, the Peregrine Fund sponsored a conference that brought together for the first time wildlife biologists and human health experts to examine the implications of ingesting spent lead ammunition.
"The overwhelming message from the conference was that people just haven't thought about the possibility that lead bullet fragments could be a source of sub-lethal human poisoning," said Rick Watson, vice president of the Peregrine Fund.
Calls have already begun for a nationwide ban on lead ammunition. The Humane Society of the United States, as well as a 2008 California Condor Blue Ribbon Panel sponsored by the American Ornithologists' Union and Audubon California, have recommended that hunters everywhere switch to alternative ammunition.
Condor 208 barely survived her massive lead poisoning. After she endured five stressful weeks of rehabilitation at the Los Angeles Zoo, veterinarians released her back into the chaparral-covered mountains near Big Sur. Then, in the spring of 2007, Condor 208 and a mate nested in a remote sandstone cliff, and she gave birth to the first condor chick born in Central California in more than 100 years. The baby condor was named Centennia.
Because the ban on lead ammunition is so new, Joe Burnett still has to test condors for lead poisoning. But he is hopeful that someday he can dispense with his syringe and field blood lab. For the first time in decades, the condor's prospects look brighter.
Additional research will be needed to investigate more fully the potential human health risks of ingesting lead from hunter-shot game. In the meantime, across the country most hunters continue to use lead bullets to shoot the game they bring home for their families to eat. Many of them are unaware of the hidden danger that could lurk in their meat.