Two disparate options:

1) Go to a site/ecosystem that has high levels of a heavy metal and isolate on solid media for that species (using the metal as part of your plate-based selection). I believe this is how Shewanella oneidensis was discovered/isolated (there's a silver utensil factor near by).

2) Take a species/strain that either has low tolerance or no tolerance and use sub-inhibitory levels of the heavy metal in the medium to passage in vitro; each passage increasing the heavy metal concentration (if possible when you manage to create a 'more tolerant' strain/mutant). This could end up happening because of actual mutations or regulation; one which would be 'long-lasting' and then other transient.

Taking sample from contaminated area like waste contaminated, electronics contaminated land and isolate it on soilid media amended different concentration of heavy metals, then the bacteria which grow on particular concentration of heavy metals then it will be tolerant bacteria