MICROBIAL AND GEOCHEMICAL ENVIRONMENT OF THE STERLING MINE DISCHARGE IN THE MIDDLE ANTHRACITE FIELD IN SHAMOKIN, PA

The Northern, Middle and Southern Anthracite Fields of Pennsylvania are greatly impacted by acid mine drainage (AMD). In this study, we regularly documented the microbiological community and geochemical conditions of the outflow from Sterling Discharge in Shamokin, PA. This discharge enters Shamokin Creek and has the notable orange sedimentation and sulfur smell of a typical AMD site. A microbial mat noted in 2004 is still extant at the discharge portal. SEM images of samples taken from the mat indicated several microbial morphologies, including those of Gallianella and Leptothrix. Weekly samples were taken from the mat as well as from three downstream sites over twenty-seven weeks starting in March 2006.We recorded the growth of the microbial mat at the discharge portal using scaled digital photographs. In addition, we sampled the water chemistry at the 4 sites. Geochemical data collected on site included pH, dissolved oxygen, conductivity, temperature, turbidity, water depth, and flow rate. Dissolved iron, sulfate and TDS concentrations were measured in the laboratory on collected samples. There was little variability in the values for pH (~6.0), DO (~0.9 mg/L), TDS (~644 mg/L), temperature (~12.8°C), dissolved iron (~20 mg/L) and sulfate (~360 mg/L). Turbidity, water depth, and flow-rate had much greater ranges in values (0-39 NTU, .25-.33 m, 0.0-0.9 m/s respectively) Previous data collected from this site is consistent with the current data. Near neutral pH discharge values in the Middle Anthracite Field are not uncommon. Extent of the microbial mat varied greatly with water levels and flow rates. SEM images of samples of the microbial mat indicate two distinct morphologies making up the bulk of the mat's structure, consistent with data from the 2004 study. June flooding has scoured the four sample sites; the remainder of the study will start from a clean slate.