Sawyer makes a heavy-duty filter for a little more $$ that does viruses, and I'd imagine metals and contaminants as well. Could be wrong.

http://smile.amazon.com/Sawyer-Products-SP191-Purifier-Assembly/dp/B0051HHNJ8/ref=sr_1_7?ie=UTF8&qid=1400769680&sr=8-7&keywords=sawyer+filter