We really need a better word than "contaminated" here. "Contaminated" implies that the objectionable substance is there as the result of someone's bad behavior.

We really need a better word than "contaminated" here. "Contaminated" implies that the objectionable substance is there as the result of someone's bad behavior. Sometimes, of course, it is. But not always. There are a lot of places where the soil and/or groundwater has a lot of lead, arsenic, mercury, what have you, because that's just the way the geology is and always has been, even before humans existed.