A few weeks ago, I poured a few grams (can't remember exact amount) of potassium permaganate crystals into some warm-hot water on a friend's advice in order to help my crushed toenail heal faster. I didn't stir...the crystals mostly sank to the bottom and the water took on a purplish color. After bathing my foot for a few minutes, I decided to nope out of it. There was no visible staining. I let it dry for a little bit then washed my foot in the shower.
What's the likelihood that there still was residue remaining after washing my foot; after these weeks, is there still residue possibly remaining? Say I visit a river and go for a swim - would there be adverse effects on the organisms there?
Sorry if this is a really stupid question. I regretted taking my friend's advice the moment I searched up some of the downsides of using potassium permaganate.