MICROBIOLOGY OF THE BAUXSOL REMEDIATION OF I-99 ACID ROCK DRAINAGE: PRELIMINARY STUDIES

Construction of I-99 near State College, PA has led to the removal and redistribution of 900,000 cubic yards of pyritic rock along the highway, resulting in acid rock drainage (ARD) problems. Pilot studies are underway to test the effectiveness of Bauxsol application in remediation of pyritic rock and ARD in situ. Groundwater and soil samples were collected from both a Bauxsol treated and untreated area, within the I-99 remediation site. Analysis of water samples by epifluorescent microscopy determined cell density and morphology of microbes present. In addition, water samples were used to inoculate iron and sulfur medium cultures to determine iron and sulfur oxidizer presence. In both the water and soil samples, clone libraries were created to determine diversity. Results show an increase in the microbial population of the treated samples, with a possible decrease in microbial diversity. The culture studies indicate a definite presence of iron and sulfur oxidizers, in both treated and untreated groundwater samples, implicating a continued microbial contribution to ARD problems even after Bauxsol application.