I've used countless amounts of lead in my tanks and have seen no ill effects from it. As Sirminion said in another thread, lead is not used anymore and it is just a heavy metal alloy.
If it really was lead it would have to contain a health warning when it was sold telling you not to eat it (IIRC).
I would be a little suspect of rubber bands, but then they are used in reef tanks which are far more sensitive than freshwater...So should be fine.