Thanks so much. I have really been wondering about that in relation to a filter's capacity for the heavy metals and minerals. The streams, I really do wonder about; as most of them at some point seem to go through an area with tailings. But, I could ask local guides about that. I do know cyanide should be a non-issue. I mess with that stuff very often in the pure form. In nature, it converts to inert (thiocyanate) very quickly.

So, don't get any from the pools, but I should inquire about the streams.

P.S. the area I go to is the Ouray & Silverton area. Family actually has a hunting cabin (no elect./no running water) on Red Mountain Pass.

Thanks.