Pennsylvania has a long history of coal mining dating back to the 1700’s has left a legacy on the landscape. Abandoned mines create the aqueous and oxidizing environment required to dissolve pyrite (FeS2) and cause acid and metals to leach from the remaining rock and drain into nearby waterways. Coal mine discharges (CMDs) can result in a trickle of contaminated water, or a gush of thousands of gallons a day (Figures 2 and 3). The amount of discharge can make a difference in the total amount (flux) of iron (Fe) and sulfate (SO4) produced by these abandoned mines over time. Pennsylvania has over 3,000 miles of streams contaminated by drainage from abandoned CMDs. Toxic metals in CMDs cause environmental impairment by killing plant and animal species, reducing biodiversity, disrupting the food chain, destroying the buffering capacity of water bodies, and altering vital habitats (Gray, 1997). Fe is removed from solution through precipitation. There have been many studies on the downstream transformations and fate of contaminants such as Fe and pH, but few studies have focused on geochemistry at the point of discharge and how it has changed over time. Studies have also been limited by focusing only on concentration, and not including flux. To solve this gap in research, samples collected from CMDs in this study are compared to previous studies conducted in 1975, 1991,and 1999 to determine changes in water chemistry and mineralogy at CMDs (Growtiz et al., 1985; Wood, 1991; Cravotta, 2008a, 2008b).
Jill Burrows is a Ph.D. Candidate in Earth and Environmental Sciences at Lehigh University. Her dissertation is focused on the geochemistry and hydrology of abandoned coal mine discharges, how they have changed over time, and the controlling factors to variations in geochemistry. She is the current President of the Graduate Student Senate, and earned a master’s Degree at Lehigh University as well in 2010, studying the long-term attenuation of heavy metals at a Superfund Site.