Day 91: Lead risk from venison, with a grain of salt

Date posted: April 25, 2009
Posted in: 100 Days of Science | Culture & society | The wild in wildlife
Comments: 4 Comments
white_tailed_deer1

White-tailed deer.

A new study is sounding the loudest alarm yet about lead poisoning from venison. 

The study, issued this week in the journal PLoS ONE, analyzed 30 white-tailed deer carcasses hunted under normal conditions and found that all of them contained lead fragments, as did a variety of butchered products. And the tainted products raised lead blood levels in pigs that ate them, in a controlled study.

“We conclude that people risk exposure to … lead from bullet fragments when they eat venison from deer killed with standard lead-based rifle bullets and processed under normal procedures,” wrote the authors, led by W. Grainger Hunt, a senior scientist with the Peregrine Fund. “At risk in the U.S. are some ten million hunters, their families, and low-income beneficiaries of venison donations.”

It’s a fair warning, and I’d be likely to heed it. I have no reason to doubt the science. But the context for the findings is sticky, and even a little suspect.

CONDOR EXHIBIT

California condors. AP photo.

First of all, the Peregrine Fund is a conservation organization that has spearheaded California condor reintroduction efforts along with lead bullet bans meant to protect the birds. The bans have proved controversial with hunters, who complain that the alternative, copper bullets, don’t kill deer as readily, leaving them to die longer and painful deaths.

A separate study last fall out of North Dakota was the first ever to confirm elevated blood lead levels in people, including children, who eat venison and other game. But none of the blood lead levels in that study exceeded federal regulations.

According to the new study, that’s no comfort.

Hunt and his co-authors make bold statements about lead risks, alleging for starters that the government’s regulations are based on “thresholds of overt toxicity and on apparent acceptance that norms in lead concentrations in a society enveloped in lead-permeated exhaust fumes and lead paint must somehow reflect organic tolerance.” That fact isn’t referenced, but most of their subsequent statements are. I’ve left the links so you can read them for yourself:

Medical science has since concluded that virtually no level of lead exposure can be considered harmless in consideration of its many sublethal, debilitating, and often irreversible effects [2]. Lead quantities formerly regarded as trivial are associated with permanent cognitive damage in children [3], including those prenatally exposed [4]. Lead is associated with impaired motor function [5], attentional dysfunction [6], and even criminal behavior [7][8]. Release of lead stores from bone exposes fetuses during pregnancy [9], and adults late in life [10][11]. Lead is implicated in reduced somatic growth [12], decreased brain volume [5], spontaneous abortion [13], nephropathy [14], cancer, and cardiovascular disease [15][16].

Authors of a recent government study out of Wisconsin have also expressed concern, particularly about venison that’s donated to charity food pantries, “as this program is an important outlet for harvested deer while also serving a population having a greater than average exposure to lead in the home.”

Health officials in both Wisconsin and North Dakota mandated inspections of such meat late last year, after physicians and others expressed concerns about lead fragments.

Both hunters and meat processors can help prevent contamination, health officials are pointing out, by thoroughly cleaning lead fragments from the bullet entrance path. 

Also, the Wisconsin Department of Health Services “recommends the use of non-lead ammunition as the simplest and most effective solution to lead poisoning, in both humans and wildlife, arising from the consumption of deer killed with lead ammunition.”

That ought to sit right with the Peregrine Fund. And it makes sense to me. 

But here’s where my appreciation for the new study breaks down. 

I like the Peregrine Fund. I’ve written stories about their heroic efforts to bring back California condors. I’ve watched condor releases on the Grand Canyon’s North Rim, and I’ve hiked deep into the Grand Canyon to observe nest sites. The biologists are dedicated and passionate about bringing the ancient raptors back.

I do not have direct personal experience that can attest to their dedication to matters of public health. 

That is to say, they may or may not be right about the grave risks of lead toxicity below federally acceptable levels. Certainly it’s a good idea for hunters and processors to clean the lead fragments out of the bullet entrance paths, and certainly it’s good to switch from lead to copper bullets whenever possible. 

But I’d rather hear the health reasons from public health experts, and I suspect the hunters would, too.

I think the Peregrine Fund should stick to protecting the California condor — not delve into the public health arena, especially with an alarmist tone. To me, it looks a little dishonest. It looks like a thinly-disguised (albeit heartfelt and well-intended) effort to protect condors that oversteps its bounds.

Source: The PLoS ONE study

4 Responses to “Day 91: Lead risk from venison, with a grain of salt”

  1. Sadie on April 25th, 2009 12:03 pm

    I’m really glad you wrote about this. I did stories for The Environment Report a few months back on the preliminary study findings and the impact of lead on condors. As I was researching, I kept getting hung up on the type of bullets and the velocity some bullets have over others.

    It’s an important point. Bullets coming from a high powered rifle (most often used today in hunting deer and used in all of the studies) explode at a high rate sending fragments much further than say a more “traditional” bullet that has less torque behind it. Most bullets are 60% lead with the rest copper.

    I agree with you that this research is really meant to help California Condors. But I also, after talking with experts at the CDC, believe there’s more reason to study lead bullets on wild game. They flat out told me not enough is known about the impacts of lead bullets and it’s an area that has flown under the radar for years until the issue with the Wisconsin Food Pantries came up. I would expect more studies on the impact of lead bullet fragments on humans will surface in the coming years.

    Thanks for an awesome blog post! I just had to chime in!
    Sadie

  2. Grainger Hunt on April 27th, 2009 3:04 pm

    Dear Anne

    As an author of the lead-in-venison paper, I want to respond to your appraisal of our motives in doing the work. First, please take the time to read the medical literature on the effects of lead on human health, especially children. You will be amazed with the findings during the past five years, and I think you will agree that we do not overstate the potential hazard. I also urge you to look into the history of lead in gasoline, its enormous implications for public health, and the sustained negligence of society in dealing with it for so many decades.

    You are right that our job is condor restoration, but it became obvious when we began x-raying deer in 2003 that hunters and their families were likely to be consuming lead. At the time, few people were aware of bullet lead as a potential pathway of lead exposure. As responsible citizens and scientists, we could not ignore our insight, so we looked into the health implications with a carefully designed study that has been peer-reviewed and published in a scientific journal. What would you have done in our place?

    Your skepticism is healthy, but it is unfair to assume we have ulterior motives. We are especially frustrated with reporters who parrot the words of industry representatives who don’t like what we have found and choose to smear our integrity and sow fear that our motive is to eliminate hunting and guns, rather than seek a solution to the problem. Those claims are false. The fact is that hunters in Arizona are valuable supporters of condor conservation, providing food for these birds in winter months; it is healthy food provided it is shot with lead-free ammunition. But lead residues from ammunition in hunter-killed game are often fatal to wildlife, and they are an apparent health risk to people. The conference we held in Boise last year (https://www.peregrinefund.org/lead_conference/2008PbConf_Proceedings.htm) provides ample evidence.

    Grainger Hunt
    The Peregrine Fund

  3. Weekly PLoS ONE News and Blog Round-up « everyONE – the PLoS ONE community blog on May 8th, 2009 12:34 pm

    [...] Fragments in Venison from Rifle-Killed Deer: Potential for Human Dietary Exposure was covered by Anne Minard and the Hominin Dental Anthropology [...]

  4. everett on May 21st, 2009 6:48 pm

    bunk!not true as we hunters cut out the wound channel. been eating venison for 67 years & my I.Q. is higher than ever. an anti hunter/gun issue. disgusting false issue.