Lead shot is a greater source of human lead contamination than previously assumed

Is lead shot environmental pollution? This is a question that is now being asked in many countries across the world.

Lead Shot Environmental Pollution

If you consider that the number of Guillemots and Eider ducks shot in Greenland alone numbers at 300,000, (most are shot in the winter time). These birds form a large part of the diet in that country. Traditionally these animals are shot with ‘lead shot’ which is then consumed by the human population in levels far higher than these recommended by the FAO/WHO. Despite visible shot being removed the fragments and smaller particles of lead caused when the shot fragments upon impact with the animals bone skeleton.

Lead content in these two species alone prompted the National Environmental Research Institute (NERI) to conduct research and the results reveal that the presence of lead is up to 8 times as concentrated in Eider duck as it is in Guillemots. The theory for this is simply that the duck is harder to kill therefore needs more shot to do so. It was also discovered that lead present in the breast is 7 times greater than previously recorded. This would seem to point towards lead shot environmental pollution being a real issue.

You can read a full environmental report by UNEP  if you follow this link.

Lead Shot Environmental Pollution has been subject to research for more than a century especially in North America.

Simply put lead serves no purpose in aiding biological processes, in large enough doses it can be fatal to wildlife, especially birds and mammals. Despite this knowledge literally multiple tonnes of lead is deposited into the soil by game and target shooters and prior to a ban in 1999, wildfowling.

Assuming the spent pellets are food or grit they are ingested by birds such as pheasant, ducks and geese; these in turn get ingested by predators or scavengers higher up the food chain. The lead is broken down by acids in the digestion system and enters the bloodstream causing lead poisoning to some degree.

Obviously the amount of lead deposited is in direct proportion to its use; for example there will be less when the land is subject to seasonal activities such as wildfowling and game shooting but clay shooting is an all year round pastime. Prior to the ban a study of the wetlands in the UK revealed densities of u to 300,000 pellets/ha in the top 15cm of sediment. The type of sediment has an effect, if it is soft then the shot sinks out of reach but heavier sediment such as clay leaves the lead nearer the surface where it can be ingested.

If we compare the figure above of 300,000 pellets/ha to these recorded at the end of a normal game shooting season of 107,639/ha in the top 1cm of soil, this represents a 300% increase. However this pales into insignificance on clay pigeon and skeet ranges. With an average of 36 g of lead shot per cartridge results in a staggering 3.7 billion/ha. Now if that isn’t lead shot environmental pollution I don’t know what is!

Lead Shot Environmental Pollution

Estimates state that it might take 40 – 70 years for the lead to break down and 100 – 300 years for it to completely decompose.

The presence of ingested lead pellets in waterfowl can vary between <10% and 70% for any particular species, whereas in game birds it is lower at <5%. Studies of Mallards in particular have tried to estimate how many might die from lead poisoning but the birds diet confused the results when some birds died after ingesting a single pellet compared to others that remained unaffected after ingesting 30 or more.

Interestingly those birds with lead embedded into muscle tissue were unaffected and this might suggest that wounded birds that recover are subsequently unlikely to suffer from lead poisoning. Another anomaly is that game birds can afford themselves a measure of protection through their ability to void lead pellets quickly thus avoiding ill effects.

Raptors are exposed to lead through dead birds left on the shooting fields or wounded animals that provide an easy kill. Scavengers access it through gut piles left in situe by hunters.

Raptors are adept at expelling shot through regurgitation as it is mixed in with inedible parts of the prey. The Kestrel is able to expel within 24 hours in comparison to the Bald Eagle which take on average 12 hours to 48 days.

The problem is not the larger parts of the lead shot but the fragments and particles that are ingested and not expelled. X-rays have shown lead deposited along the bullet tract. Raptors are particularly vulnerable due to their long life span {allowing for lead to build up over time] and slow breed rate. Despite various worldwide bans raptors are still coming into contact with lead infected prey, it’s just prey that is exempt from being targeted with lead shot. At present there are no figures relating to lead poisoning in raptors and very little information concerning mammals and scavengers.

Lead Shot Environmental Pollution

As I mentioned previously legislation came into force in England in 1999 outlawing the use of lead shot for wildfowling. Local bans have been in place in the USA since 1977, this went nationwide in 1991. This has been emulated by Canada, Australia, New Zealand and many European countries. Strangely enough there have been no follow up studies in England to find out the effect of the ban, however they have been conducted in the USA due to the fear of lead shot environmental pollution.

The good news [in the USA] is that ban compliance is 99% and a study conducted 6 years later revealed that out of 15,000 Mallards shot along the Mississippi flyway showed that the ingestion rate had been reduced by 75% with the death rate dropping from 4% in 1938 – 1954 to ≤ 1.44% in 1996 – 1997. In real terms this means that the ban saved 1.4 million ducks out of a population of 90 million from fatal poisoning.

Doing our bit for the environment at Marksman Leisure

At our Marksman Leisure Oaklands site we use Hush Power 28 gram with 7.5 shot (ideal for clay shooting) for both novices and the experienced gun, two reasons for this choice of cartridge are

  1.  The recoil experienced is minimal, as we want the user to remember the breaking of the clay and not the thump in the shoulder as often all you hear is what about the ‘kick’.
  2.  We have consideration for our neighbours and believe that quietening the sound from the gun benefits both users and neighbours.

The Hush Power cartridges are more expensive to buy, by some £60 per 1000, but the benefits are greater for all concerned.

I hope you have enjoyed this article concerning lead shot environmental pollution, please leave your comments and delve into the rest of the site.

Thanks, Mark

Lead Shot Environmental Pollution.