Paper No. 10
Presentation Time: 10:40 AM


STOLZ, John F.1, EASTHAM, J. Lucas2, RUTTER, Jennifer2, DUGAS, Oliver2, JOSHI, Samir2, BASU, Partha3, BAIN, Daniel J.4 and KONDRATYUK, Tetiana1, (1)Biological Sciences, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282, (2)Center for Environmental Research and Education, Duquesne University, Pittsburgh, PA 15282, (3)Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282, (4)Geology and Planetary Science, University of Pittsburgh, 4107 O'Hara Street, 200 SRCC Building, Pittsburgh, PA 15260,

The extraction of natural gas from unconventional sources such as shale using the process of horizontal drilling and hydraulic fracturing requires millions of gallons of water. The process generates fluids (e.g., flow back and produced water) with high levels of total dissolved solids (TDS). In Pennsylvania, produced water used for recycling can be stored in open impoundments. The objective of this study was to analyze the ionic composition of the produced water from several sources and characterize the microbial community from two different impoundments as well as local surface water sources. Chloride, bromide, fluoride, nitrate, nitrite, phosphate, arsenate, and arsenite were measured using an ion chromatography system equipped with both UV/Vis and conductivity detectors. Cation analysis was done using ICP-MS. A semi-synthetic enrichment culture medium was designed that mimicked the composition of the produced water (e.g. high TDS). Robust enrichment cultures were readily obtained from the impoundment samples and found to grow over a wide range of salinities. DNA extracted from aerobic cultures was used for 16s rDNA clone libraries and Automated Ribosomal Intergenic Spacer Analysis (ARISA). ARISA and 16S gene sequencing revealed differences in bacterial composition between the impoundment samples and freshwater samples. Sequencing of a 16S gene clonal library indicated the enrichment cultures were comprised of Halomonas, Thalassospira and other genera related to halophilic and petroleum degrading species. Two strains of moderately halophilic bacteria, LP-1 and SWPA-1 were subsequently obtained in pure culture and found to be most closely related to Salinivibrio costicola and Bacillus firmus respectively. Both grew well in medium containing high salt (60 g/L NaCl), strontium (2.75 g/L) and barium (150 mg/L). These results suggest that the produced water and impoundments harbor unique microbiota adapted to the high salt and dissolved solids that are not indigenous to the surface fresh water ecosystems typical of the region.