Richard Kasunic

Rana Xavier/Flickr

Acid mine drainage is the most widespread water pollution problem in Pennsylvania. When water wells up inside abandoned coalmines, it leaches the iron compound ‘pyrite’ from the rock to form an acidic, sulfuric brine — called “yellowboy” for its color. As the pressure builds in the empty, underground mines, it often begins to seep out, the risk of a blowout increases, and, at times, the yellowboy could end up flowing into the nearest stream and killing wildlife.