SHOULD WE TREAT THE MINE DRAINAGE OR TREAT THE CREEK? CHARACTERIZATION OF ONEIDA #3 ACID MINE DRAINAGE AND ITS EFFECTS ON LITTLE TOMHICKEN CREEK, HAZLETON (LUCERNE COUNTY), PA

Drainage from the Oneida #3 mine tunnel discharges into Little Tomhicken Creek near Hazelton, PA. Historically, high aluminum concentrations and low pH have been the contamination problems in drainages from the Oneida mine and other mines in this area of the Middle Anthracite Field in eastern Pennsylvania. A passive limestone treatment system is currently under construction to raise pH and mitigate the aluminum contamination from the Oneida #3 discharge. On September 12, 2009, we conducted a field study to assess present chemistry of both the drainage and Little Tomhicken Creek upstream and downstream of its confluence with the mine drainage. We analyzed pH, specific conductance (TDS) and dissolved oxygen in situ at 11 sites. Large triplicate samples were collected at each site and filtered at a central location. Alkalinity was determined immediately after filtering. Additional filtered subsamples were acidified and kept chilled for subsequent analysis of Cd, Pb, Mg, Ca, Mn, Cu, and Fe by flame atomic absorption and of Al by colorimetry. A third set of triplicate filtered subsamples was frozen for later analysis of sulfate, chloride, bromide, fluoride, nitrate, nitrite and phosphate by ion chromatography. The low pH of the mine drainage (pH 5) was quickly neutralized after the confluence with Little Tomhicken Creek (pH 7.8). Maximum dissolved aluminum in the mine discharge was 0.12 ppm, an order of magnitude higher than the values for Little Tomhicken Creek. Nonetheless, the aluminum concentrations were lower than the 0.6 ppm values measured in a similar study conducted in 2006. Dissolved aluminum concentrations measured in September 2009 were not only within national drinking water standards, but below the 0.5 ppm levels reported to be toxic to aquatic life. Chloride and nitrate levels were much higher in Little Tomhicken Creek than in the mine drainage, and values of both remained high downstream of the confluence. At the time of this study, it appeared that anthropogenic impacts on Little Tomhicken Creek were greater than the impact of the mine drainage.