PHYSICAL AND CHEMICAL PARAMETERS DETERMINING BACTERIAL GROWTH OF ACID MINE DRAINAGE SITES IN SOUTHEAST OHIO

This study focused on highlighting the connection between the physical, chemical, sedimentary, and microbial aspects of various acid mine drainage settings of contrasting chemistry. In addition, a comprehensive thesis model was suggested to explain the interconnected relationships of this data set. The first 30 meters were evaluated for Pine Run (Fe), Esco No. 40 (Fe and Al), York Clay No. 4 (Mn), and Sines No. 2 (Al) coal mines. The acidophilic microbial taxa evaluated were Thiothrix sp.(any), Gallionella ferruginea, and Leptothrix discophora. Through principal component analysis (PCA) and a Spearman correlation matrix (n=20) a number of correlations were found to describe our model. The results of this study indicate a strong relationship between distribution of total Fe, and SO₄, in the sediment due to physics of flow. Statistical analyses suggest precipitation of Mn into the sediments could occur at the medium-coarse sand (0.5-0.99 mm) grain size fraction and Fe likely precipitates as a larger grain size fraction than this. Both Thiothrix and G. ferruginea taxa shared a positive correlation with velocity, and L. discophora shared a negative correlation to flow velocity. Variable flow conditions within the first 30-meters of the mine opening can alter distribution of precipitates to deposit medium to coarse sand grain size fractions, reoxygenate waters, and alter pH to create supersaturated conditions for the minerals basaluminite, amorphous Fe(OH)3, gibbsite, barite, and goethite. Results from this study also indicate G. ferruginea is likely favored in Fe contaminated systems, L. discophora could be the more abundant in Mn and Al contaminated mines, and SO₄ contaminated drainage favors Thiothrix. Geochemical modeling results agree with water quality tests and field observations for each site.