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The science on lead

This bald eagle suffering from acute lead poisoning died not long after arrival. (Photo: Wildwoods)

In a March 27 letter to the Budgeteer commending the usefulness of lead, Allan Kehr quotes material from the National Rifle Association website Hunt for Truth. This site seeks to cast doubt on an issue free of doubt, that lead is a toxic substance hazardous to both humans and wildlife. We are amazed that this scientific fact has become politicized and is still disputed.

Yes, lead is useful. It's easy to mine and smelt. It's soft, malleable and easy to work with. Humans have been using lead for thousands of years, for plumbing, soldering, ceramics, paints, batteries, ammunition and as a gasoline additive.

There's just one problem with lead: It's poisonous. In humans it rarely kills outright or we would have stopped using it centuries ago. Instead, its effects are usually slow and insidious.

Lead has caused many health problems over the centuries. (1) Wonder why there's such concern about lead in the Flint, Mich. water supply? Though lead poisoning is treatable, its effects on brain development in children are irreversible. (2)

Even low levels of lead in children can result in behavior and learning problems, lower IQ, hyperactivity, slowed growth and other problems. (3) The World Health Organization states, "There appears to be no threshold level below which lead causes no injury to the developing human brain." (4)

In adults, low-level lead exposure can result in hypertension, decreased fertility, cataracts, nerve disorders, muscle and joint pain and memory and concentration problems. (5)

As we've become aware of lead's dangers, we've gradually limited its uses. In the U.S., lead has been removed from paints, gasoline, ceramics used for food preparation and storage, solder used in food cans and modern plumbing. These are simple, sensible measures our society enacted to protect us and our children.

Why is lead ammunition used in hunting a problem? Why not just cut out the meat around the bullet wound and discard it? Unfortunately, when a lead bullet hits an animal, it fragments into many pieces. These spread out into the tissues as far as 14 inches from the wound. (6) Many of these fragments are dust-like in size, too small to see or sense when chewing.

So unless we cut out and discard the meat in a diameter of 28 inches around the wound channel — and that's half your deer, unless you take head or neck shots — when we eat venison taken with lead or feed it to our children, we may be eating lead.

Will we or our children die from eating lead fragments in our venison? No. Will it even have a noticeable immediate or long-term effect? Probably not. In humans, lead is a slow, subtle poison unless we consume a lot at once.

The EPA states that there is no known safe of lead in humans, especially children. Though few cases of acute and life-threatening lead toxicity are seen in the U.S. these days, low levels of lead are not safe.

Are people who eat game taken with lead ammunition at higher risk for the ill effects of lead? Absolutely. A 2008 study performed by the Centers for Disease Control in North Dakota examined blood lead levels in people and correlated these with whether and how often they ate wild game, and whether that game was taken with lead ammunition. (7)

The study found that people who ate wild game harvested with lead ammunition had higher lead levels than those who did not. Also, the more frequently they ate such game, the higher their lead levels were. Based on these findings, the North Dakota Department of Health recommends: (8)

• Pregnant women and children younger than 6 should not eat any venison harvested with lead bullets.

• Older children and other adults should take steps to minimize their potential exposure to lead.

• The most certain way of avoiding lead bullet fragments in wild game is to hunt with non-lead bullets.

Because of the higher acid content in their digestive tracts, scavenging birds like bald eagles and condors who eat fragments of lead in carrion are much more likely to suffer acute lead poisoning than humans. Many of these birds die.

The Raptor Center of Minnesota has clearly linked lead-based ammunition to the seasonal spike in lead poisoning in bald eagles. (9, 10) There is also robust science demonstrating lead poisoning in California condors is from spent lead ammunition in carrion. (11, 12)

Mr. Kehr states that banning lead ammunition in condor areas in California has had no beneficial effect on California condor populations. However, since condors fly where they please, they cross into neighboring areas and scavenge from dead animals there, some of which were killed with lead. Also, California condors are present in other states like Arizona, where lead ammunition has not been banned.

The science regarding lead is clear: No amount is safe. Lead is a health issue, not a political one. Think using lead bullets for hunting is safe? Think again.

Peggy Farr is a volunteer and board member of Wildwoods and works in human health care. 

Wildwoods is a 501(c)(3) wildlife rehabilitation organization in Duluth. For information visit www.wildwoodsrehab.org, call (218) 491-3604 or write to P.O. Box 3161, Duluth, MN 55803.

Wildwoods will hold a fundraiser at Clyde Iron Works on 3-7 p.m. on Sunday, May 1. Tickets ($30) are available at www.wildwoodsrehab.org or at the door.

Footnotes

[9] Cruz-Martinez, L, PT Redig, and J Deen. 2012. Lead from spent ammunition: a source of exposure and poisoning in bald eagles.  Human-Wildlife Interactions 6(1): 94-104.

[10] Kramer, J. and P T Redig. 1997.  Sixteen years of lead poisoning in eagles, 1980-1995: An epizootiologic view.  J. Raptor Research 31(4):327-332.

[11] Church, ME, R Gwiazda, RW Risebrough et al.  2006. Ammunition is the principal source of lead accumulated by California condors re-introduced to the wild.  Environ. Sci. Technol. 40(19):6143-50.

Peggy Farr

Peggy Farr is a volunteer and board member of Wildwoods and works in human health care.

Wildwoods is a 501(c)(3) wildlife rehabilitation organization in Duluth. For information on how you can help wildlife, including volunteer opportunities, visit wildwoodsrehab.org, call (218) 491-3604 or write to P.O. Box 3161, Duluth, MN 55803.

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