Lead...
OK - my reply is completely lacking in sense of humor, but I've done a tiny bit of clinical research on lead, so you asked...! The problem is similar (but not actually as bad) as people who work in letterpress printing, where the actual type is made of lead and there is a much greater potential for lead exposure.
A) The big issue w/ lead is in kids, with developmental delay and long term effects of lead exposure. Usually that has to do with ingestion (by mouth). Usually paint chips. Technically, if there is lead dust, that can also go through skin or even lungs, but that's really not the issue here. Very high levels of lead can lead to a multitude of other problems, including nervous system problems in adults, bone marrow suppression... As with anything, wash your hands before eating or preparing food. I've heard old letterpress people mention "white lead" or a whitish deposit on old type as being more dangerous, but I don't know if that's necessarily true.
B) It obviously depends on what your tacks are made of. And unfortunately, you'll probable never know EXACTLY what your tacks are made of. But experience from everyone else around here suggests that it's probably not lead, or at least not a lot of lead. I've heard that some old canvas fillers had lead - if you're really concerned about lead exposure, perhaps gloves in dealing with canvas removal would be a good idea. Maybe most of that lead has dissolved away in local waterways... Curious what others have to say about fillers.
C) My hunch is that there's probably a much greater risk from accidental tack ingestion than lead absorption from the tack. Don't know if there's any issue with teeth and metal. At some point, I'd be curious if there's any literature out there dealing with electricians and lead - with such high exposures to solders, wiring, my hunch is that they are at a MUCH higher risk, but I don't know that for certain.
D) I must admit, I'm a bit fascinated by the risks associated with hobbies. I know, strange, but it's the doctor in me. Risks associated with canoeing / kayking (on the water) are obvious, but I'm a bit surprised by the number of organic solvents, epoxies (with sensitization allergies), inhalational exposures to dusts and particulates, plus the risks associated with power tools, fire, cuts, etc. It's a tough hobby to pursue in a limited space, and I really admire the discipline involved in maintaining a clean environment. I wish I had a shop, but rather work on limited tasks indoors and any sanding / finishing outdoors.
OK - I'm no fun!
