Ruined?

This is one of Riya's shirts. It is one of my favorite of her shirts. I think it's ruined. When we went to the hot springs in Idaho, I packed the wet towels in with the rest of the dirty clothes just to get back to the Birds' house. Apparently, the water from the springs has something red in it. It showed up on a few of our white clothes. I  have washed them several times and it is stained. Today, I tried again with Riya's shirt - stain remover and bleach in the wash. Nothing. Boo.
Any suggestions?  John suggested soaking it in bleach... which I haven't tried yet.