I am a hobbyist and a crafter working with cast models. These modles are up to 80% lead, with the rest being tin or similar soft metals. They are made in a mould, so they often have mould lines that need to be scraped off with a knife. But doing this can create lead dust which will pollute the immediate working environment. I had the idea of doing any scraping while the model was completely submerged in water. The theory is that small particles will be caught in suspension in the water, and the water can then be filtered or otherwise safely disposed of. (In case this needs illustrating, I have made a video of my method: link). My question is essentially, "will this method successfully control the spread of lead dust into my working environment, or am I missing something important?"
Another option is to buy a small table-top soldering booth. They make acrylic booths with HEPA filtration. You'd put your workpiece in the booth and reach in from the front with your hands. Air is pulled inward and exhausted out the back. For cleanup, I'd suggest something like D-Lead wipes - they contain EDTA or something equivalent that will help to trap and retain lead and other metals in solution. You should also get a colorimetric lead test kit (I've seen them on Amazon) so you can do surface swab sampling in your work area. Color change on the swabs will allow you to visualize the effectiveness of your control measures. Lastly, tell your doctor you are working with lead, and they can arrange a blood lead level test during your annual physical.
It's risky. The water being filtered off is not good enough to reuse the water. This is because some lead dust might be small enough to fall with the liquid. It is also because if there is any metal higher than lead in the electrochemical series, some lead would fall into solution. Either way, you'd have to dispose of the water safely since it would likely be contaminated.
Would it catch the dust? Yeah it would. You'd also need to thoroughly wash the knife. Or maybe it wouldn't. If your lead dust is super small, some amount could be flung and fly. If your dust is more like sand, well it'll probably stay at the bottom of the water.
I'm no physicist, but I would think the particles would be larger when cut underwater. So you're probably okay.
I would advise placing other precautions such as wearing a mask with a very fine filter. For example a dust mask. It would also be a good idea to wear gloves and long sleeved clothing. But I'm not sure how you would safely clean off your clothing after use.
At that point, even if you get some lead on you, it's not gonna be super bad since there would be very little and since it is metallic. Do note that aqueous and organometallic heavy metals are very, very toxic even compared to the regular metals.
Also, the deeper your lead is, the less likely it is to escape. And whatever tool you're using, you need to make sure it has no lead dust before it leaves the water.