Geochemical and isotopic variations in shallow groundwater in areas of the Fayetteville Shale development, north-central Arkansas

Toward High-Resolution Vertical Measurements of Dissolved Greenhouse Gases (Nitrous Oxide and Methane) and Nutrients in the Eastern South Pacific

“…The latter is a highly sensitive and reproducible technology of direct absorption spectroscopy, which determines nanomolar levels of CH 4 and N 2 O (Crosson, 2008;Berden and Engeln, 2009;Warner et al, 2013;Roberts and Shiller, 2015;Yver Kwok et al, 2015). Despite a substantial increase in the number of GHGs measurements using CRDS, primarily due to improvements in commercially available instruments (i.e., from Los Gatos Research and PICARRO Ltd.), there is an urgent need to improve gas separation techniques.…”

Unconventional Fossil Fuel Reservoirs and Water Resources

“…Further confounding the question of whether hydraulic fracturing can contaminate drinking water wells with methane is the variation in geology among shale plays. Warner et al (2013) in conjunction with USGS analyzed groundwater samples from drinking water wells above the Fayetteville Shale in Arkansas and found no statistical difference between water from wells within 1 km of gas wells and water from wells > 1 km from gas wells. In the seven wells where methane concentrations were >0.5 mg l À1 , a carbon isotope analysis revealed that the methane was likely of biogenic origin (Kresse et al, 2011).…”

Chemical constituents and analytical approaches for hydraulic fracturing waters

“…Thermogenic methane sources have been associated with hydraulic fracturing operations whereas biogenic methane sources are typical of non-active sites [20]. Likewise, total dissolved solids including cations, metals and radioactive elements have been detected in surface and groundwater sources [17,22,25,26]. Interestingly, organic compounds have not been studied as often as gases or inorganic elements.…”

“…The most comprehensive study showing the impact of hydraulic fracturing in water quality was recently published by Vidic et al [14]. Several papers have addressed the specific impacts in water resources as well as the slow contamination of shallow groundwater [15][16][17][18][19][20][21][22]. Most particularly some studies have identified certain pathways of water contamination, which consist mainly of the following: transportation spills, stray gas contamination, leaks from well casing, leaks from fractured rocks, site discharges, accumulation of radioactive elements in soil and sediments, and ultimately wastewater disposal [14,15,19].…”