Haven't personally seen it it a body of water, but I have heard of it. The pH of some the precip that falls in the east can be very low. I am sure a lot of it depending on the buffering ability of the soils where the precip falls.
When I was in NC this past summer at the high elevations in the spruce-fir forests, the acid precipitation damage was interesting to see. It has certainly affected both aquatic and terrestrial ecosystems in the east.
