Iron doesn’t dissolve easily, but groundwater picks up iron from rocks. That’s why well water sometimes stains your sink orange.
Those orange marks are dissolved iron that turned back into rust when it hit air. It’s like a zombie process: iron hides in water, then rises to attack your white shirt.
1 Solubility of iron and transfer from catchment to aquatic system
Gross but Cool: The Iron-Eating Lake
Lake Nyos in Africa is full of dissolved iron from volcanic rocks. The water looks clear—until you stir it. Then it turns blood red.
All that dissolved iron suddenly oxidizes. It’s nature’s magic trick: transparent to vampire in seconds.
