Occurrence and sources of radium in groundwater associated with oil fields in the southern San Joaquin Valley, California

Author Posting. © American Chemical Society, 2019. This is an open access article published under an ACS AuthorChoice License. The definitive version was published in Environmental Science and Technology 53(16), (2019): 9398-9406, doi:10.1021/acs.est.9b02395.Geochemical data from 40 water wells were used to examine the occurrence and sources of radium (Ra) in groundwater associated with three oil fields in California (Fruitvale, Lost Hills, South Belridge). 226Ra+228Ra activities (range = 0.010–0.51 Bq/L) exceeded the 0.185 Bq/L drinking-water standard in 18% of the wells (not drinking-water wells). Radium activities were correlated with TDS concentrations (p < 0.001, ρ = 0.90, range = 145–15,900 mg/L), Mn + Fe concentrations (p < 0.001, ρ = 0.82, range = <0.005–18.5 mg/L), and pH (p < 0.001, ρ = −0.67, range = 6.2–9.2), indicating Ra in groundwater was influenced by salinity, redox, and pH. Ra-rich groundwater was mixed with up to 45% oil-field water at some locations, primarily infiltrating through unlined disposal ponds, based on Cl, Li, noble-gas, and other data. Yet 228Ra/226Ra ratios in pond-impacted groundwater (median = 3.1) differed from those in oil-field water (median = 0.51). PHREEQC mixing calculations and spatial geochemical variations suggest that the Ra in the oil-field water was removed by coprecipitation with secondary barite and adsorption on Mn–Fe precipitates in the near-pond environment. The saline, organic-rich oil-field water subsequently mobilized Ra from downgradient aquifer sediments via Ra-desorption and Mn/Fe-reduction processes. This study demonstrates that infiltration of oil-field water may leach Ra into groundwater by changing salinity and redox conditions in the subsurface rather than by mixing with a high-Ra source.This article was improved by the reviews of John Izbicki and anonymous reviewers for the journal. This work was funded by the California State Water Resources Control Board’s Regional Groundwater Monitoring in Areas of Oil and Gas Production Program and the USGS Cooperative Water Program. A.V., A.J.K., and Z.W were supported by USDA-NIFA grant (#2017-68007-26308). Any use of trade, firm, or product names is for description purposes only and does not imply endorsement by the U.S. Government

The Water-Energy Nexus of Hydraulic Fracturing: A Global Hydrologic Analysis for Shale Oil and Gas Extraction

Shale deposits are globally abundant and widespread. Extraction of shale oil and shale gas is generally performed through water-intensive hydraulic fracturing. Despite recent work on its environmental impacts, it remains unclear where and to what extent shale resource extraction could compete with other water needs. Here we consider the global distribution of known shale deposits suitable for oil and gas extraction and develop a water balance model to quantify their impacts on local water availability for other human uses and ecosystem functions. We find that 31–44% of the world's shale deposits are located in areas where water stress would either emerge or be exacerbated as a result of shale oil or gas extraction; 20% of shale deposits are in areas affected by groundwater depletion and 30% in irrigated land. In these regions shale oil and shale gas production would likely compete for local water resources with agriculture, environmental flows, and other water needs. By adopting a hydrologic perspective that considers water availability and demand together, decision makers and local communities can better understand the water and food security implications of shale resource development

Desalination of Shale Gas Wastewater: Thermal and Membrane Applications for Zero-Liquid Discharge

Natural gas exploration from unconventional shale formations, known as “shale gas,” has recently arisen as an appealing energy supply to meet the increasing worldwide demand. During the last decade, development of horizontal drilling and hydraulic fracturing (“fracking”) technologies have allowed the cost-effective gas exploration from previously inaccessible shale deposits. In spite of optimistic expansion projections, natural gas production from tight shale formations has social and environmental implications mainly associated with the depletion of freshwater resources and polluting wastewater generation. In this context, the capability of desalination technologies to allow water recycling and/or water reuse is crucial for the shale gas industry. Advances in zero-liquid discharge (ZLD) desalination processes for treating hypersaline shale gas wastewater can play a key role in the mitigation of public health and environmental impacts, and in the improvement of overall process sustainability. This chapter outlines the most promising thermal- and membrane-based alternatives for ZLD desalination of shale gas wastewater.This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 640979

Examining the Feasibility of using Coal Mine Drainage as a Hydraulic Fracturing Fluid

Much of the current concern about hydraulic fracturing revolves around the treatment and disposal of wastewaters that come up out of the well after fracturing has occurred. These “produced waters” and “flowback waters” in some cases are high in concentrations of total dissolved solids (TDS), naturally occurring radioactive material (NORM), and metals. There are currently many ways these wastewaters are managed including being recycled on site, treated at commercial waste water treatment plants, or shipped away for storage in federally permitted underground injection wells. This study suggests that by supplementing wastewater with high-sulfate coal mine drainage (CMD), on site recycling can be even more effective through the removal of high metal concentrations and NORM from the wastewater. This could potentially allow for 100% waste water recycling, saving local water resources, while a legacy environmental problem may be remediated. This study was focused on the idea that by mixing coal mine drainage with flowback or produced water, many of the negative characteristics of both fluids can be remediated. The sulfate can be removed from the coal mine drainage, and with it, the barium and radium can be removed from the coal mine drainage. Mix ratios of 1:4, 1:2, and 3:4 were used for this study and in almost every case a majority of the radium (100% for each ratio), barium (75, 90, and 80% respectively), and sulfate (90, 75, and 40% respectively) precipitated out of the mixture. Barium and radium concentrations were found to be strongly correlated within each the sample (r2 of .815). In addition to that, the removal of those solutes was also found to be correlated (r2 of .75). Finally, using spatial analysis and a number of input factors, it was found that on average the use of coal mine drainage is between $30 and$200 thousand more expensive to use per well than fresh water. These results indicate that mixing AMD and flowback water is an effect means of water treatment for re-use as hydraulic fracturing fluid. Although not currently cost effective, the potential to clean up a legacy environmental problem has inspired policy makers to begin the process of making the use of coal mine drainage more cost effective with less legal consequence

The Water-Energy Nexus for Hydraulic Fracturing

The water energy nexus represents the intersection of water use, energy production, electricity generation, and waste generation and disposal. The rapid rise of unconventional natural gas and oil production through the combined processes of horizontal drilling and hydraulic fracturing have shifted the energy dynamic in the United States. Concurrently, the rising utilization of unconventional gas and oil production has intensified the water use for hydraulic fracturing and generation of flowback and produced water associated with shale gas and tight oil production. Among the major environmental risks associated with the rise of unconventional oil and gas exploration water availability, water contamination from leaking or disposal of wastewater, and adequate disposal of the wastewater are the key issues associated with the water-energy nexus. This dissertation aims to quantify the water use for hydraulic fracturing across the U.S., evaluate the water use for electricity production from natural gas in comparison to coal combustion, estimate the flowback and produced water production, and assess possible recycling of oilfield water through irrigation in California. This dissertation describes the water footprint of hydraulic fracturing by examining total water use, water use per well, water use per length of horizontal well, and the changes in water use through time. The data show that hydraulic fracturing water use per well has been increasing between early stages (2008-2012) to later stages (2012-2016) of operation. In addition to water use, this dissertation estimated waste water generated from unconventional oil and gas wells and find a concurrent increase in flowback and produced water (FP water) per well through time. Using salinity as a marker to distinguish FP water from water injected for hydraulic fracturing, this dissertation observes the sequestration of the injected freshwater, while the return flow composed primarily of more saline formation brines entrapped within the shale formations. In addition, this this dissertation explored two downstream impacts of the increasing water use and FP water generation. First, as abundant natural gas resources from the expansion of hydraulic fracturing have shifted the electricity sector from primarily coal- to primarily natural gas-fired, this study examined the impact increasing water use associated with hydraulic fracturing has had on power plant lifecycle water consumption and withdrawal. The study found that despite increasing water use for hydraulic fracturing, natural gas-fired generation on average used less water for cooling relative to coal-fired generation. Finally, this this dissertation examined the risks from recycling of oilfield produced water (OPW) as an agricultural makeup water source. The data from field studies in California show that by using low salinity OPW, farmers are able to successfully recycle OPW without risking metals accumulation in soil and consequently in crop and human health.</p

Factors Affecting Glucose Uptake in Tissue-engineered Human Skeletal Muscle

Tissue-engineered skeletal muscle myobundles offer a promising approach for developing a human in vitro model of healthy and diseased muscle for drug development and testing. Their three-dimensional structure offers a better model of the organization of native skeletal muscle than monolayer culture does, and their amenability to an array of functional measures provides a multifaceted account of the tissue’s health. One such functional measure is the metabolic state of the myobundle, which in an in vitro model of healthy skeletal muscle should reflect the metabolism of native muscle. However, skeletal muscle cultured in vitro is exposed to artificially high levels of nutrients meant to promote cell growth, and it exhibits altered glucose uptake, with high rates of glycolysis and a dampened insulin response. Inflammation is closely linked with skeletal muscle metabolic dysfunction, and the field could benefit from a human tissue-engineered myobundle model of inflammation to elucidate mechanisms of disease progression and to examine drug safety and efficacy in inflamed muscle.We first characterized the glucose uptake and insulin response of tissue-engineered myobundles in the basal state and in response to treatment with metformin and an HDAC inhibitor. We then imparted greater physiological relevance to the system via altered culture conditions and examined the impact on myobundle metabolic and contractile function. Finally, we validated the ability of pro-inflammatory cytokine exposed-myobundles to recapitulate key aspects of inflammation-mediated skeletal muscle dysfunction.We found that myobundles exhibit insulin sensitivity similar to that of in vivo skeletal muscle, but insulin responsiveness is substantially lower, in accordance with other in vitro studies. Metformin treatment stimulated a robust increase in basal glucose uptake, and treatment with the HDAC inhibitor 4-PBA enhanced myobundle contractile function and insulin responsiveness. We showed that altering myobundle culture conditions to provide more physiologic nutrient availability was sufficient to metabolically reprogram the myobundles to a less glycolytic state. To model an inflammation-mediated disease state, we exposed myobundles to pro-inflammatory cytokines and found that the inflamed myobundles exhibited contractile dysfunction, a robust secretion of pro-inflammatory cytokines, and increased basal glucose uptake while still retaining a functional response to metformin treatment. Overall, this work validates the suitability of a tissue-engineered skeletal muscle model for detecting metabolic perturbations mediated by drug treatment, nutrient availability, and inflammatory conditions.</p