Dirty Mouth?

There was seven ions that we tested in our experiment. Those ions were Carbonate, Chloride, Chromate, Iron, Lead, Phosphate, Sulfate. In my example two, I test the water from a water fountain and it tested positive for Iron. i wasn't too surprised. In my example three i tested water from a pond near mason town and it tested positive for Iron and Phosphate. I thought the water would be very polluted from the looks of the water. I did not find any pollutants.