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There has been a bit of a brouhaha, to say the least, over the National Park Service’s press release distributed on 10th March saying they were going to phase out all ammo and tackle containing lead by 2010.

First off, let’s have a look at what a ban on lead ammo and tackle would actually mean. What it applies to is the use of bullets and shots (the little lead spheres that go inside cartridges), and sinkers (attached to the end of a fishing line to get a better cast distance and to weigh down the lure) in National Parks. This ban certainly doesn’t equate to a ban on hunting (the NRA is not a force to be taken lightly) and, as mentioned in the press release, non-toxic alternatives (tungsten, copper, and steel) are pretty freely available throughout the USA. The California Department of Fish and Game has produced this list of approved non-lead ammo manufacturers, and there’s a similar list of approved non-lead shots for wildfowl hunting by the Fish and Wildlife Service.

So why ban lead, anyway? Well, you probably already know that lead is bad for people, which is why you won’t see any new lead plumbing (including solder), lead paint, or leaded petrol in the UK and elsewhere. Here is a really good list of things that lead has been shown to do to people (by mimicking calcium in the body’s chemical reactions), from lowering our IQ, turning us into criminals, and causing schizophrenia to killing us. Lead was used for so long in plumbing because it is so non-corrosive (i.e. non-biodegradable), so over time it can build up to toxic levels (bioaccumulate). Although absorption of lead via skin contact is very low, absorption of ingested lead is much higher and can build up, especially if you’re a carnivore and therefore eating lots of things with low levels of lead them. It all adds up.

For instance, lead poisoning is of particular concern for birds of prey, which eat the carcasses of animals that may have been shot with lead ammo. Lead poisoning is a primary cause of death in the critically endangered California Condor, and it’s already illegal to shoot deer, bear, wild pig, elk, pronghorn antelope as well as coyotes, ground squirrels, and other non-game wildlife in areas designated as California condor range. Just a few days ago a California Condor was taken in by the Los Angeles Zoo suffering not only from lead poisoning but also from having been shot. The Peregrine Fund (a birds of prey charity) hosted a conference last May called “Ingestion of Lead from Spent Ammunition: Implications for Wildlife and Humans”, in which several papers were presented with evidence that eating game shot with lead ammo substantially increases lead concentrations in the blood (pdf here). As in humans, lead is stored in bone and soft tissues, especially kidneys and brain, impairing reproduction and causing cognitive and behavioural defects as well as tissue damage and death.

The use of lead shot when hunting waterfowl is already banned by the Fish and Wildlife Service since 1991, but is still permitted for shooting game birds in neighbouring fields (e.g. pheasants) and even to hunt snakes in the same water body. Waterfowl may be particularly susceptible to inadvertent ingestion of lead shot due to their feeding habits. For example, swans swallow grit to help with digestion, but shots are the same sort of size and shape that they can be easily confused and inadvertently ingested. According to the Swan Society, it only takes three or four shots to kill a swan, but in the major swan die-off of winter 2000/2001 up to 30 shots were found in each bird. The use of lead sinkers was made illegal in the UK over 20 years ago, and in some US states it’s illegal to sell certain lead sinkers or jigs, but nationwide the Environmental Protection Agency estimates:

approximately 2,500 metric tons of lead, zinc, and brass sinkers (over 98 percent of the volume represented by lead), an estimated 480 million sinkers, are manufactured each year in the United States.

This phenomenal number is so high because lines break not too infrequently, leaving the sinkers in the water, so they have to be replaced. You can imagine for yourself what this means for the number of lead sinkers that get lost in the US’s water bodies every year, and how much lead this constitutes. Straight Dope estimates up to 3000 tons of lead entering Canadian and US waterways annually.

So why are people still up in arms (so to speak) about switching to lead-free? I have seen a lot of people claiming that there is no evidence that lead ammo/tackle damages wildlife in any way, but there is so much evidence out there to suggest lead has dangerous implications for the health of both wildlife and humans (see the AEWA’s list of papers regarding waterbirds, the proceedings of the Peregrine Fund’s conference on spent lead ammo, and Needleman’s book “Human Lead Exposure”) that I find it hard to believe that people still believe hunting with lead can continue without repercussions. I think it’s partly about tradition and self-reliance: for a lot of people hunting can be a way to distance oneself from bureaucracy and regulation, and return to tradition. It’s also not necessarily immediately obvious that lead ammo and tackle have a detrimental effect on wildlife, because the fact that hunting is still such a popular and historic activity and there’s still wildlife to be had seems to suggest that its practice is sustainable. Consider, though, that lead sticks around in the environment and that for example in California the number of Lifetime Hunting licenses issued has tripled since 2000 to 4,159 – there is more lead in the environment now than there ever has been. Furthermore, birds of prey are already pretty rare (some more than others, after suffering hugely from other persistent toxins, e.g. DDT), so it’s not like you’re going to see them falling out of the sky en masse, but the fact that California Condors are showing up pretty regularly with lead poisoning has got to mean something, right?

Also, I’ve seen people on forums saying if they were going to get lead poisoning (and by implication if lead poisoning were an issue for serious consideration) they would have done so by now, because they used to carry lead pellets around in their mouth, and regulating lead comes under the same category as constantly using anti-bacterial hand wash. One problem with that is that and that although absorption of lead through the skin may be minimal, absorption of ingested lead is considerably higher, especially in children (40%). The effects of low levels of lead may also not be immediately obvious or expected – behavioural changes, problems with hand-eye co-ordination, hyperactivity, lowered IQ and cognitive function, higher incidence of miscarriage, impotence, abdominal pain, etc. But the thing you have to bear in mind is that lead may build up in the body’s soft tissues and over time more serious effects can be seen, in some cases leading to death. See Herbert Needleman’s book “Human Lead Exposure” and LEAD Action News’ list of referenced effects of human lead exposure for papers on lead toxicity in humans. When it comes to equivalent effects in wildlife, it’s also important to consider that feeding habits (whether it’s birds of prey feeding on big game killed with lead ammo or swans inadvertently swallowing shot along with grit) and animal size are factors.

To cut a long story short, this is a very complex issue, and although there is an awful lot of support for the ban, there is also an awful lot of opposition. As a result of this, on the 18th of March NPS issued a new press release, effectively backtracking:

1. Nothing has changed for the public. We are simply announcing the NPS goal of eliminating lead from NPS activities to protect human and wildlife health.
2. We will work to clean our own house by altering NPS resource management activities. In 2009, we will transition to non-lead ammunition in culling operations and dispatching sick or wounded animals.
3. In the future, we will look at the potential for transitioning to non-lead ammunition and non-lead fishing tackle for recreational use by working with our policy office and appropriate stakeholders/groups. This will require public involvement, comment, and review.

I was quite saddened and frustrated by this, but I am ever-hopeful that by effective provision of information and public involvement by the NPS and other environmentally-minded people, those that opposed this ban this round will consider the effect that lead-containing hunting tools are having on wildlife and come to understand that the benefits of a lead ban are worth the minimal hassle of using non-toxic alternatives.