by Sir Cumference » 29 Jan 2013, 21:08
Quite a necro-post, but I'll add a bit anyway.
Lead and bullets: Lead is great for projectiles because it is easy to shape by melting or swaging, it is relatively cheap and it has a high density. A lot of other metals can beat lead on one or two of these, but none is superior on all three points.
Toxicity is irrelevant when talking lead projectiles. You need the effect to take place in seconds or minutes, not in a couple of years.
It is well documented that lead and especially water and fat soluble lead compounds are toxic. But to hurt you, it has to enter your body in some way.
- inhalation
- ingestion
- through the skin
Are the main routes, with inhalation and ingestion being the most efficient. Our skin is designed to be a barrier to the world, the lungs and intestines to actively absorb things.
Metallic lead is not very soluble, but it will spontaneously form carbonates and oxides on the surface. These are more or less soluble, but will dissolve in the acid in your stomach. Handling lead and forgetting to wash your hands before eating, puts you at risk.
Breathing lead dust was a serious risk at foundries casting lead containing alloys. Workers cutting up scrap metal, either containing lead or painted with lead paint have also supplied interesting cases.
Another route to inhalation are indoor firing ranges with inadequate ventilation. Projectiles hitting steel backstops will shatter and the lead containing primer compounds produce a cloud of lead particles at the firing line.
I know a couple of instructors who have had "too high" levels of lead when they were tested.
Organic or inorganic?
Carbonates, nitrates, sulfates, oxides and other inorganic lead compounds are toxic, but will often react to form insoluble compounds. A lead bullet in neutral soil will form a white insoluble crust, and stay that way for centuries.
Organic lead compounds is another story. They are soluble in non-polar phases, in the body that translates to fatty tissue, blubber, nerves and the brain. You really don't want any nerve damage!
In the bad old days whem tetraethyllead was added to gasoline, large amounts of lead oxide was released from cars, and banning TEL in gasoline caused a sharp drop in the lead blood levels.
Common sense and hygiene should be used when handling lead.
Nickel is a funny metal. Shiny, hard, relatively cheap, easy to electroplate on almost anything....... And it can cause a really nasty allergy in some people.
And once you have the allergy, it stays with you!
In the EU, it is forbidden to use nickel compounds (that can release nickel, many stainless steels do not, even though they contain lots of nickel) in objects intended to be in contact with the skin, such as jewelry and buttons.
The risk of allergy should be taken very seriously.
If you are predisposed, you may develop an allergy, but you can't say how much is needed to do it.
You should not eat the oxidation on copper and brass. Copper compounds are toxic, but not nearly as bad as lead.
Clean brass and bronze is pretty safe.
Iron and stainless steel is safe too, but can pose a risk when welding or grinding.
Tin and low-lead pewter is perfectly safe too (some of the organic tin compounds on the other hand are very toxic!)
Aluminium is safe, but the safety of aluminium compounds is a topic of discussion. The acute toxicity is relatively low, but there are some studies raising concerns about long term effects...... I'm not worried.
But it is not always straight forward.
The effect will depend on what you are exposed to, how much, for how long and to some degree who you are.
To be quite honest, I think we should be more concerned about the plastizisers, flame retardent and Perfluoro-compounds we are exposed to.
~ Leatherworking, blacksmithing , woodworking and programming are the most pervertable skills you can learn! ~