That's interesting, Jon. Just what is in that water that makes in so environmentally bad? This is Not a "snark," or a "trick" question. I'm, sincerely, interested in what it is that Minnesota does not consider polluted that we might.

Assuming it's untreated sewage, it's likely full of organic matter. Organic matter rots and removes oxygen from the water, creating dead zones. Organic matter also fertilizes water, helping to create algal blooms.