Contaminated Beavers?

I came back with ticks, scratched, and burrs after trekking into the woods for this picture, today.
Waterville officials plan to apply for a federal grant to clean up contaminated wastewater lagoons on West River Road that contain effluent from the former Wyandotte mill across the road. Here, a beaver dam is visible in one of the lagoons with the mill visible in the background.