Thanks to Peter for this link, in which we learn that the biggest single point source for pollution in the Chesapeake Bay is… the Lackawanna River. More than fifty years after the end of anthracite mining around Scranton, the flooded mines and acid drainage are a continuing hazard to the people of the area, and to anyone unfortunate enough to be downstream. Choicest quote:
Peering through a metal grate down to the borehole, one sees the churning violent water emerging from deep under the ground. What comes out runs along a trough and then enters the Lackawanna River, where the iron from the acid mine water begins to kill the river by scavenging oxygen and coating the river bed with iron, giving it an orange look and a rotten egg smell.