The Great Lakes is an enormous watershed, and there's a mix of urban and rural challenges. A city like Toronto with five million people in the GTA, and similarly Chicago, Detroit, and Cleveland, can certainly exert all kinds of strains on Lake Ontario, whether they're effluent problems or stormwater runoff.
What's your sense when you talk about water quality in the Great Lakes? Is it more because of urban populations, or is it more because of agricultural and rural issues?