My non-scientific guess is that the most typical cause of pathological levels of iron in the human body is drinking water with high iron content.
“Though rusty water may look and taste unpleasant—and possibly stain sinks and clothing—it is not a health concern. A possible exception is people with hemochromatosis, a rare disorder that causes excess iron accumulation in body organs.”
https://www.berkeleywellness.com/healthy-eating/food-safety/article/rusty-water