BigHornRam
Well-known member
By The Associated Press
Wednesday, November 12, 2008 7:58 PM MST
JACKSON -- Preliminary results of a study by a University of Montana graduate student suggest that lead bullets may be poisoning grizzly bears in the Yellowstone ecosystem.
Tom Rogers sampled blood from 13 grizzlies during hunting season.
He found that nearly half had elevated levels of lead, possibly because the bears had eaten lead bullet fragments in big-game carcasses left behind by hunters.
Lead typically stays in an animal's blood stream for about two weeks before it is deposited in organs and other tissues. Lead poisoning in human children can cause serious health problems including stomach pain, anemia, lower intelligence and poor school performance.
In all, Rogers checked blood samples of 24 grizzly bears for lead contamination. The 11 bears sampled outside of hunting season did not have elevated lead levels.
"There is a pretty substantial difference between hunting season and nonhunting season blood-lead levels," Rogers said.
He said he'd need more samples to confirm his results.
"It's pretty preliminary right now," he said. "It's just for one season. But as of right now it looks pretty clear."
Rogers defined an elevated level of lead as 10 micrograms per deciliter of blood, the same threshold for human lead poisoning.
Some researchers and health professionals have advocated for a threshold of 5 micrograms or even 2 micrograms. A blood lead level of 60 micrograms in a human would require medical attention.
The highest level of blood contamination Rogers sampled in a grizzly was roughly 28 micrograms per deciliter.
"That's a pretty large chunk of lead they've eaten," he said.
Wednesday, November 12, 2008 7:58 PM MST
JACKSON -- Preliminary results of a study by a University of Montana graduate student suggest that lead bullets may be poisoning grizzly bears in the Yellowstone ecosystem.
Tom Rogers sampled blood from 13 grizzlies during hunting season.
He found that nearly half had elevated levels of lead, possibly because the bears had eaten lead bullet fragments in big-game carcasses left behind by hunters.
Lead typically stays in an animal's blood stream for about two weeks before it is deposited in organs and other tissues. Lead poisoning in human children can cause serious health problems including stomach pain, anemia, lower intelligence and poor school performance.
In all, Rogers checked blood samples of 24 grizzly bears for lead contamination. The 11 bears sampled outside of hunting season did not have elevated lead levels.
"There is a pretty substantial difference between hunting season and nonhunting season blood-lead levels," Rogers said.
He said he'd need more samples to confirm his results.
"It's pretty preliminary right now," he said. "It's just for one season. But as of right now it looks pretty clear."
Rogers defined an elevated level of lead as 10 micrograms per deciliter of blood, the same threshold for human lead poisoning.
Some researchers and health professionals have advocated for a threshold of 5 micrograms or even 2 micrograms. A blood lead level of 60 micrograms in a human would require medical attention.
The highest level of blood contamination Rogers sampled in a grizzly was roughly 28 micrograms per deciliter.
"That's a pretty large chunk of lead they've eaten," he said.
