Ever since the invention of firearms, lead has been the metal of choice for bullets and shotgun pellets. Guns and rifles were designed with this ammunition in mind. Lead has properties that give the projectiles good range and penetration. However, lead salts and oxides (produced by chemical action on metallic lead) are poisonous; consequently, lead has been phased out of plumbing, paint and petrol for reasons of public health. Lead can also poison wildlife, and this first became apparent in waterfowl when swans and ducks, which had ingested spent lead shot and fishing weights with grit, began to die. Even though most waterfowl populations have continued to increase, the UK phased out lead in fishing weights and shot used for waterfowl shooting. These are now made of iron or other materials.
Protection of wildlife
To protect wildlife, the use of lead shot over all foreshore and specified Sites of Special Scientific Interest, and for the shooting of all ducks, geese, coot and moorhen, wherever they occur, has been illegal in England since November 1999. The Welsh Assembly imposed restrictions on lead shot in September 2002, based closely on the English approach. Scottish legislation differs from that in England and Wales in that since 2004 it has been illegal to use lead shot to shoot any species or target, including game and clays, over wetlands. Similar restrictions banning the use of lead shot over wetlands were introduced in Northern Ireland in September 2009. In Scotland and Northern Ireland it is permissible to use lead shot to shoot any species outside wetlands.
At the request of the government-convened Lead Ammunition Group, we have conducted extensive literature research to ascertain the broader impact of using lead ammunition on wildlife. The conclusions are summarised below.
The available evidence to date does not indicate that the use of lead ammunition is having a significant negative impact on the population of any UK species. It is likely that ingestion of lead results in adverse effects on individual animals, including death, and that welfare costs are incurred wherever lead is absorbed. However, no single study or group of studies adequately shows a link between spent lead ammunition and negative effects on populations overall in England.
There is evidence for direct exposure of some species to spent lead shot through ingestion along with food or grit, including gamebirds, waterfowl and other small bird species. The exposure of waterfowl is a matter regarding effectiveness of or compliance with current legislation.
There is also evidence that British birds of prey are exposed to lead in their environments. Shot birds and animals can be a source of ammunition-derived lead for predators and scavengers. This has been shown in red kite, and circumstantially indicated for buzzard and peregrine falcon. Once again, while negative effects may occur for individuals of these species, there is no evidence for impacts on raptor populations.
The above pathway does not explain the elevated lead levels observed in birds that don’t normally eat game species, including kestrel, hobby, merlin, short-eared and little owl. This demonstrates that lead shot is only one of many possible exposure sources. Studies have shown lead in birds derived from: spent shot; deposits in soil suspected to come from historic lead petrol fumes; and manufacturing processes such as mining.
Given the evidence that some shooters continue to use lead ammunition illegally, as well as the presence of legally lead-shot non-retrieved gamebirds in the environment, it is likely that scavengers may receive some lead exposure through eating these birds. However, although one might expect it, there is no evidence for this in the UK for either the crow family, or mammalian scavengers.
Increased levels of lead in the soil have been detected in shooting grounds, for example clay pigeon shoots, and this may have an impact on local plants and animals. Although the local adverse effects on individuals near such sites appears not to have a negative effect overall on species populations, this would need to be addressed as a whole.
There are certain knowledge gaps in the available literature. For example, it is widely assumed that different birds and animals respond to lead in similar ways. It is not known if this is correct or what the main variables are. It is also assumed that elevated tissue/organ levels are associated with adverse welfare impacts for individual birds or animals. Given the toxicity of lead and the lack of a lower threshold in humans, this is a reasonable assumption, but there is a lack of definitive evidence and the extent to which it is true is unknown.
Overall, increased lead exposure has negative impacts on individual birds and animals through more than one route. However, the evidence does not support adverse effects on wildlife populations in the UK. The impact of mortality caused by lead exposure is likely to be very much less than the other major causes of mortality affecting bird populations.
Protection of human health
As stated on its website, the Food Standards Agency (FSA) advice since 2012 is that “frequent consumers of lead-shot game should eat less of this type of meat”. However, it does not define what level of game meat constitutes “frequent consumption”.
It continues: “To minimise the risk of lead intake, people who frequently eat lead-shot game, particularly small game, should cut down their consumption. This is especially important for vulnerable groups such as toddlers and children, pregnant women and women trying for a baby, as exposure to lead can harm the developing brain and nervous system.”
We asked for clarification on this issue and were advised that the level of lead in game meat is very variable, therefore the FSA has not given advice regarding the number of portions that should be consumed, as it may be misleading. However, as a “rough guide”, individuals who consume game meat “more than a few times a month” should reduce their intake.
Regarding lower levels of game consumption, FSA advice is that eating gamebirds twice a year, or venison once a month, will have a minimal effect on lead exposure.
As a wildlife charity, the GWCT has no human health toxicology specialists, but those that are state that intake of lead from background sources is unavoidable, and some of the foodstuffs that we are encouraged to eat more of for health reasons (fresh vegetables, cereal products) make up a significant proportion of lead exposure in the average diet. Although the consumption of lead-shot game is completely avoidable, it comprises a very small part of our diet. The European Food Standards Authority concludes: “Game meat contributes approximately 0.05% of total dietary lead exposure in the general EU population.”
It is unfortunate that some people who would like to see all forms of shooting banned have sought to use a ban on lead as means to further their cause. This has led to entrenchment within the shooting community and stifled the important discussion about lead ammunition. Given that, at current rates of consumption, world lead deposits are predicted to run out by 2050, the necessity to develop effective alternative ammunitions is likely to become more pressing. Whilst we feel that the evidence base does not currently support further restrictions on lead ammunition, we do support:
- The wider understanding of the known risks posed by the use of lead ammunition.
- Discussion of the pros and cons of existing alternative ammunition types, and evaluation of their impacts.
- Increased research and development towards effective alternative ammunition types.
- More guidance from the FSA on how lead-shot game should be prepared and cooked to further minimise exposure to lead.
- Full compliance with, and enforcement of, existing legislation designed to protect wildlife.
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✓ The background
✓ Effects on human health
✓ Effects on human wildlife
✓ Recent government action