COMPARING THE MICROBIAL POPULATIONS OF GROUNDWATER IN THE BAUXSOL TREATED AND UNTREATED AREAS AT I-99: PRELIMINARY STUDIES

In order to remediate acid rock drainage from pyritic rock exposed during construction of I-99 near State College, a pilot study involving in situ Bauxsol application was initiated. Groundwater samples were taken from wells in treated and adjacent control areas to test the effect of Bauxsol application on relevant microbes. First, epifluorescent microscopy was used to determine cell density and morphology of microbes present. Second, iron and sulfur medium cultures were inoculated to determine iron and sulfur oxidizer presence. Finally, bacterial clone libraries were created to determine diversity. The results show there may be an increase in the microbial population in the treated samples and that populations of iron and sulfur oxidizers are able to persist despite Bauxsol application. The betaproteobacteria were the most common bacteria found including the denitrifier Azospira sp., the sulfur oxidizer Limnobacter thiooxidans, and unidentified iron oxidizers. The effects of Bauxsol on these and other microbes will have important consequences on the utility of Bauxsol in remediating ARD.