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Department of Hydrology and Water Resources, University of Arizona, 1133 E. James E, Rogers Way, Tucson, AZ 85721, USA
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- PublicationRestrictedA geochemical and stable isotope investigation of groundwater/surface-water interactions in the Velenje Basin, Slovenia(2014-03-04)
; ; ; ; ; ; ; ;Kanduč, T.; Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia ;Grassa, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;McIntosh, J.; Department of Hydrology and Water Resources, University of Arizona, 1133 E. James E, Rogers Way, Tucson, AZ 85721, USA ;Stibilj, V.; Department of Environmental Sciences, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia ;Ulrich-Supovec, M.; HGEM D.O.O., Zaloška 143, Ljubljana, Slovenia ;Supovec, I.; HGEM D.O.O., Zaloška 143, Ljubljana, Slovenia ;Jamnikar, S.; Velenje Coal Mine, Partizanska 78, 3320 Velenje, Slovenia; ; ; ; ; ; The geochemical and isotopic composition of surface waters and groundwater in the Velenje Basin, Slovenia, was investigated seasonally to determine the relationship between major aquifers and surface waters, water–rock reactions, relative ages of groundwater, and biogeochemical processes. Groundwater in the Triassic aquifer is dominated by HCO3 –, Ca2+, Mg2+ and δ13CDIC indicating degradation of soil organic matter and dissolution of carbonate minerals, similar to surface waters. In addition, groundwater in the Triassic aquifer has δ18O and δD values that plot near surface waters on the local and global meteoric water lines, and detectable tritium, likely reflecting recent (<50 years) recharge. In contrast, groundwater in the Pliocene aquifers is enriched in Mg2+, Na+ , Ca2+, K+, and Si, and has high alkalinity and δ13CDIC values, with low SO4 2– and NO3 – concentrations. These waters have likely been influenced by sulfate reduction and microbial methanogenesis associated with coal seams and dissolution of feldspars and Mg-rich clay minerals. Pliocene aquifer waters are also depleted in 18O and 2H, and have 3H concentrations near the detection limit, suggesting these waters are older, had a different recharge source, and have not mixed extensively with groundwater in the Triassic aquifer.350 98 - PublicationRestrictedA Critical Review of State-of-the-Art and Emerging Approaches to Identify Fracking-Derived Gases and Associated Contaminants in Aquifers(2019)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ;High-volume, hydraulic fracturing (HVHF) is widely applied for natural gas and oil production from shales, coals, or tight sandstone formations in the United States, Canada, and Australia, and is being widely considered by other countries with similar unconventional energy resources. Secure retention of fluids (natural gas, saline formation waters, oil, HVHF fluids) during and after well stimulation is important to prevent unintended environmental contamination, and release of greenhouse gases to the atmosphere. Here, we critically review state-of-the-art techniques and promising new approaches for identifying oil and gas production from unconventional reservoirs to resolve whether they are the source of fugitive methane and associated contaminants into shallow aquifers. We highlight future research needs and propose a phased program, from generic baseline to highly specific analyses, to inform HVHF and unconventional oil and gas production and impact assessment studies. These approaches may also be applied to broader subsurface exploration and development issues (e.g., groundwater resources), or new frontiers of low-carbon energy alternatives (e.g., subsurface H2 storage, nuclear waste isolation, geologic CO2 sequestration).143 6