Repository for Oil and Gas Energy Research (ROGER)

Abstract:
A large-scale study of methane emissions from well pads was conducted in the Marcellus shale (Pennsylvania), the largest producing natural gas shale play in the United States, to better identify the prevalence and characteristics of superemitters. Roughly 2100 measurements were taken from 673 unique unconventional well pads corresponding to ∼18% of the total population of active sites and ∼32% of the total statewide unconventional natural gas production. A log-normal distribution with a geometric mean of 2.0 kg h–1 and arithmetic mean of 5.5 kg h–1 was observed, which agrees with other independent observations in this region. The geometric standard deviation (4.4 kg h–1) compared well to other studies in the region, but the top 10% of emitters observed in this study contributed 77% of the total emissions, indicating an extremely skewed distribution. The integrated proportional loss of this representative sample was equal to 0.53% with a 95% confidence interval of 0.45–0.64% of the total production of the sites, which is greater than the U.S. Environmental Protection Agency inventory estimate (0.29%), but in the lower range of other mobile observations (0.09–3.3%). These results emphasize the need for a sufficiently large sample size when characterizing emissions distributions that contain superemitters.

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Risk communication scholars have examined public perception of scientific consensus on a variety of politically controversial risk topics; social-psychological factors that shape such views (i.e., political ideology); and effects on issue attitudes. Few studies, however, have combined these antecedents and outcomes within a single framework – one that describes how politically polarized attitudes emerge via ideologically-divergent perceptions of scientific agreement. We address this shortcoming in the context of an emerging risk topic – unconventional oil and natural gas development (UOGD) in the United States – that is politically controversial and where scientific agreement on specific impacts along with value-laden assessments of benefit and risk are subjects of scholarly and public debate. Using a quota survey of United States adults (n = 700), we find that political conservatism heightened support indirectly via: (1) perceived scientific consensus that benefits outweigh the risks and, in turn, the belief that UOGD’s health, economic, and environmental impacts in the United States have been positive and (2) lower perception of scientific consensus that risks outweigh benefits, which likewise heightened beliefs that aforementioned impacts have been positive. We discuss implications for risk communication research related to energy development.

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Hydraulic fracturing, often called fracking, is a drilling technique that accesses previously inaccessible oil/gas reserves. Although the process could aid U.S. energy independence, it is controversial and public opinion is divided. Guided by agenda-setting and framing, this study content analyses news coverage of fracking (N = 524) across cable networks (CNN, Fox News, MSNBC). Results show cable news lacks substance and relies on thematic framing. While all networks failed to provide factual information, issue-related topics discussed and sources used vary ideologically. Theoretical and practical implications, which include the potential for priming audiences and influencing future behaviors and judgments, are discussed.

Abstract:
A survey with an embedded experiment was conducted to test how residents would respond to a commitment by oil and natural gas producers to conduct nearby fracking operations in a manner that is more protective of health and the environment than existing state and federal regulations. The experiment specifically assessed how the use of independent third-party certification of operations coupled with "beyond compliance" practices would influence local public support for oil and gas development. The state of Colorado was chosen due to its long history of oil and gas development, its leadership amongst states in advancing fracking, and the current local-level conflicts surrounding oil and gas development. A public opinion survey (N = 390) of a representative sample of Colorado residents found that "green certification" of a production company's activities led to substantially increased levels of support for a hypothetical nearby oil and natural gas project. Our findings suggest that oil and gas developers can obtain greater public support for their projects by voluntarily engaging in practices that are more protective than current state and federal regulations together with third-party certification of those practices. In effect, these coupled actions serve as a mechanism that promotes a firm's "social license to operate".

Abstract:
The rapid development of shale gas in the United States raises potential concerns about environmental impacts. This paper examines how environmental regulations are enforced in shale gas development in Pennsylvania's Marcellus Shale development and the resulting compliance behaviors, employing the economic literature of crime and punishment as the analytical framework. A three-level hierarchical linear model (HLM) is used to analyze the enforcement and compliance performance of regulators and shale gas operators, respectively, employing data spanning from 2011 to 2017. Significant variation in the environmental non-compliance exists between both wells and operators. The empirical results suggest progressive directions for adjusting environmental enforcement strategies in Pennsylvania and provide implications and references for other regions with similar shale gas ambitions.

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Fracking drilling has opened a discussion on the role of technological developments in economies engaged in shale oil and gas formations. Oil and natural gas production opened new possibilities for employment benefits and housing prices decreases. This paper explores, for the first time, the impact of fracking on housing prices across Oklahoma's counties, spanning the period 2000–2015. Through panel methods, the findings show a positive effect on housing prices, while this positive effect gains statistical significance only over the period after the 2006 fracking boom. The results survive a robustness check that explicitly considers distance and groundwater-dependency issues.

Abstract:
The impacts associated with unconventional natural gas development (UGD) via hydraulic fracturing have generated considerable controversy and introduced terms such as “fracking” into the public lexicon. From a climate change perspective, transitioning from fossil fuels to renewable sources in order to potentially avoid the worst consequences of a warming planet will need to also consider the climate implications of increased UGD and natural gas use that follows. Specifically, how much greenhouse gas is emitted as natural gas is extracted, transported, and consumed relative to other energy sources? Is UGD a “cleaner” energy source? Compared to what? Does it postpone or “bridge” the transition from fossil fuels to renewable energy?Public perception of UGD’s climate impacts not only reflect individual attitudes but broader social discourse among stakeholder groups. Understanding these perceptions, their psychological and social factors antecedents, and how to engage audiences on this topic will play a key role in UGD’s long-term trajectory, especially as it relates to climate change. An added challenge is that most public opinion studies specific to UGD’s climate impacts (and indeed UGD in general) are limited to the United States, Canada, and a few countries in Europe and Africa, with other parts of the world entirely absent. Nonetheless, the studies that do exist highlight several common themes. In particular, UGD tends to be viewed as cleaner relative to fossil fuels because of the belief it produces less carbon emissions as a result of natural gas extraction and consumption. However, it tends to be viewed as dirtier relative to renewables amid the belief that it increases carbon emissions. This finding complements research showing that natural gas occupies a middle ground between renewables and other fossil fuels in terms of acceptance. Moreover, the extent UGD serves as a bridge energy source remains contentious, with some arguing that it and the natural gas it produces complement fossil fuels and facilitates a transition to renewables, while others claim that UGD entrenches society’s continued reliance on the former. Overall, despite the contentious nature of these issues, UGD’s climate impacts appear less salient across countries than other health, environmental, and economic impacts, perhaps because they are psychologically distant and difficult to experience directly.Amid efforts to convey the public health risks associated with a changing climate, we believe that emphasizing the public health dimensions of UGD’s climate impacts can potentially make them more psychologically tangible. Positively framed messages emphasize that reducing carbon emissions tied to both unconventional natural gas extraction and natural gas consumption (relative to other fossil fuels) and thus mitigating the resultant climate change that follows benefits public health. Conversely, negatively framed messages emphasize that increasing carbon emissions (relative to renewables) and thus amplifying the resultant climate change adversely affects public health. At present, though, there is little evidence as to how these messages affect the perceived connection between UGD’s climate impacts and public health and, in turn, support for UGD versus other energy types. Nor is it clear how these outcomes may vary across countries based on public sentiment toward UGD and climate change along with a variety of psychological and social factors that influence such sentiment. Data available for some countries offers tantalizing scenarios, but we remain limited due to the lack of social science research in countries outside the United States and a handful of others. We call for cross-national comparative studies that include places where UGD—and social science research on it—is still maturing.

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Unconventional drilling technologies like hydraulic fracturing and directional drilling have markedly increased oil and gas production in the United States while also bringing production in proximity with many communities. Foundational research in rural sociology predicts the rise of local “boomtown” problems like excessive alcohol consumption as a result of sudden energy booms. In this paper, we use data from U.S. counties to understand the relationship between energy production and alcohol consumption. Results suggest that oil and gas production has very modest effects on binge drinking and heavy drinking, and that these effects may vary by gender and across U.S. states.

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Concerns over possible impacts from the rapid expansion of unconventional oil and natural gas (ONG) resource development prompted a regional domestic well sampling program focusing on the Carboniferous Maritimes Basin bedrock in southeastern New Brunswick, Canada. This work applies recent developments in robust multivariate statistical methods to overcome issues with highly non-Gaussian data and support the development of a conceptual model for the regional groundwater chemistry and the occurrence of methane. Principal component analysis reveals that the redox-sensitive species, DO, NO3, Fe, Mn, methane, As and U are the most important parameters that differentiate the samples. Permutation-based MANOVA and ANOVA testing revealed that geology was more important than geographic location and topography in influencing groundwater composition. The statistical inferences are supported by chemistry trends observed in relation to road de-icing salt and other saline sources. However, source differentiation between Carboniferous brines, entrapped post-glacial marine water and modern seawater cannot be made. Furthermore, Cl:Br ratios lower than those of seawater or regional brines suggest an origin related to the diagenesis of organic-rich sediment and that the groundwater may be influenced by local low permeability units. Combined spatial, statistical and chemical analysis shows that, while trace or low levels of methane, <1 mg/L, are found ubiquitously throughout the Maritimes Basin, elevated concentrations, >1 mg/L, are associated with the Horton Group, consistent with it being the host and inferred source of ONG resources in the province. The highest methane concentrations (14–29 mg/L) were detected in the region with a complex history of cycles of uplift and erosion which, in some locations, resulted in the juxtaposition at the surface of the Horton Group with several other groups of the Maritimes Basin. It is thought that proximity to the Horton Group can lead to naturally high methane concentrations in non-ONG-bearing units.

Abstract:
Microbial activity in flowback and produced water (FPW) may negatively influence shale oil and gas extraction. However the impacts of using recycled produced water (RPW) for subsequent fracturing jobs are not well-understood. In this study, we compared time series of FPW samples from two horizontally fractured wells drilled into the Duvernay Formation in Alberta, Canada, well 1 used RPW in the makeup of the hydraulic fracturing fluid (HFF) while well 2 did not. 16S rRNA gene sequencing and live/dead cell enumeration were used to track microbial communities. Within 20 days of flowback, total dissolved solids in well 1 and well 2 increased from 5,310 mg/L and 288 mg/L to over 150,000 mg/L, and FPW temperatures increased from 20°C and 9°C to 77°C and 71°C, respectively. Alkyl dimethyl benzyl ammonium chloride (biocide) in well 2 decreased from 25 µg/L to below the detection limit of 0.5 µg/L. Cellular biomass decreased from ~105 cells mL-1 to less than the detection limit of 105 cells mL-1 in both wells, and the community in the samples was initially diverse, but rapidly shifted to become dominated by the sulfidogenic lineage Halanaerobium. Methanogens were detected at low relative abundance within archaea. DNA concentrations in FPW after 20 days were inadequate for sequencing. Comparing the two wells, the start time of Halanaerobium enrichment was considerably shortened in well 1 relative to well 2. Our results suggest that subsurface environmental parameters primarily drive the rapid enrichment of sulfidogenic and halotolerant bacteria and current recycling strategies can facilitate the growth of these bacteria, while biocide seems to be a less important factor in this shift.

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Hydraulic fracturing (HF) operations have transformed the unconventional energy industry, leading to a global increase in hydrocarbon production. Despite this, only the US, China, Canada and Argentina currently dominate production of unconventional resources, with the majority of shale basins globally remaining unprofitable to develop. An important gap in current water-energy nexus research, which this study addresses, is the assessment of potential water use to satisfy HF procedures in emergent plays. This work presents a screening tool for assessing first-order estimates of water impacts in undeveloped shale plays, testing the approach in the transboundary Eagle Ford (EF) play in northeast Mexico. We couple surface water and groundwater stress indicators derived from global hydrological variables to depict a baseline water stress index. Relative water stress is mapped for proposed blocks to be leased by the Mexican government in the future. We simulate four HF scenarios to assess new total water stress indicators for each block, considering shale production schemes using representative well drilling density (well lateral length(s) per unit area) and HF water intensity (HF water volume per unit lateral length) from existing EF development in Texas. Results suggest that the most feasible management scenario would consider the drilling of ∼1360 new unconventional wells/yr with projected HF water use of ∼57 Mm3/yr (0.7% of the total water withdrawals). The remaining scenarios will largely affect groundwater resources. Though applied to the EF in Mexico, this screening tool can assess water use constraints in emerging unconventional plays globally.

Abstract:
During the past decades, significant progress has been made in the development of induced seismicity monitoring for related human activities. Hydraulic fracturing and induced seismicity monitoring are operating procedures for safe and effective production of oil and gas from unconventional resources, particularly shales. Hydraulic fracturing can induce seismicity through fluid injection and disturbance of subsurface stress in tight reservoirs. Most seismic events associated with hydraulic fracturing exhibit magnitude of Mw ≤ 3 and are referred to as microseismicity, while a few larger-magnitude earthquakes (e.g. Mw > 3) could also be induced by reactivating pre-existing faults. Here, we review the current status of research concerning induced seismicity monitoring for shale hydraulic fracturing. Induced seismicity contains information relating to important subsurface characteristics, e.g. rock failure potential and seismogenic zones. Microseismic monitoring is essential for reservoir characterization, e.g. fracture geometry delineation and reservoir geomechanical analysis. It is carried out with advanced acquisition, processing, and interpretation techniques, while larger-magnitude earthquakes are mainly exploited for potential geohazard management and mitigation. Challenges and prospects associated with multi-disciplines for future research and applications of induced seismicity monitoring are identified, and it contributes to achieve safe and efficient unconventional (tight) oil and gas resource exploitation.

Abstract:
Liquid chromatography quadrupole time-of-flight mass spectrometry was performed to understand how frac fluid with recycled water (RWA) and frac fluid with fresh water (FWA) compare when subjected to downhole temperature and oxidation conditions. Ethylene oxide and propylated glycol functional units were quantified from both RWA and FWA. Qualitative analysis was performed using Agilent qualitative analysis software B.06.00 based on the exact mass of the chemical compound. Acetone, aldol, alkoxylated phenol formaldehyde resin, diethylbenzene, dipropylene glycol, d-Limonene, ether salt, ethylbenzene, n-dodecyl-2-pyrrolidone, dodecylbenzenesulfonate isopropanolamine, polyethylene glycol, and triethylene glycol were detected in FWA and RWA samples. In the van Krevelen diagram, FWA and RWA show a low degree of oxidation and highly saturated organic compounds. Kendrick mass defect (KMD) analysis was applied using ethylene oxide and propylated glycol units. KMD analysis based on ethylene oxide was scattered between 0 and 0.1, while some KMD analyses based on the propylated glycol are close to 1. FWA had an average carbon number of 32.3 and double bond equivalent (DBE) of 9.8 while RWA had average carbon number of 31.5 and DBE of 9.5. RWA contained predominantly C21-C40 compounds, while FWA had a higher concentration in the over C41 range.

Abstract:
Background Thousands of chemicals exist in hydraulic-fracturing (HF) fluids and wastewater from unconventional oil gas development. The carcinogenicity of these chemicals in HF fluids and wastewater has never been systematically evaluated. Objectives In this study, we assessed the carcinogenicity of 1173 HF-related chemicals in the HF chemical data from the US Environmental Protection Agency (EPA). Methods We linked the HF chemical data with the agent classification data from the international Agency for Research on Cancer (IARC) at the World Health Organization (WHO) (N = 998 chemicals) to evaluate human carcinogenic risk of the chemicals and with the Carcinogenic Potency Database (CPDB) from Toxnet (N = 1534 chemicals) to evaluate potential carcinogenicity of the chemicals. Results The Chemical Abstract Service registry numbers for chemicals were used for data linkage. Among 1173 chemicals, 1039 were identified only in HF fluids, 97 only in wastewater, and 37 in both. Compared with IARC, we found information of 104 chemicals and 48 of them may have potentially carcinogenic risk to human, among which 14 are definitely carcinogenic, 7 probably carcinogenic and 27 possibly carcinogenic. Using the CPDB data, it suggests that 66 chemicals are potentially carcinogenic based on rats and mouse models.

Abstract:
The significant development of oil and gas from the Marcellus Shale and other geological formations in Pennsylvania over the last decade has generated large volumes of liquid and solid waste. In this paper we use data reported to the Pennsylvania Department of Environmental Protection (PADEP) to examine temporal and spatial trends in generation and management of liquid and solid waste from both conventional and unconventional oil and gas activities in Pennsylvania between 1991 and 2017. While previous assessments have examined this waste inventory in part, no complete assessment of waste quantity, waste types, waste handling practices, and spatial waste tracking has been undertaken using all currently available full years of Pennsylvania oil and gas waste data. In 2017 more than half of oil and gas wastewater by volume was reused at well pads to facilitate more hydrocarbon production while the majority of solid waste by volume was disposed of at in-state landfills. The spatial resolution of reporting of wastewater generation and handling from unconventional operations has improved substantially with recent regulations and reporting requirements; however, conventional oil and gas development was exempt from the more stringent reporting requirements and thus spatially-explicit data on wastewater generation and handling from conventional oil and gas development is still lacking. In addition, a third of the liquid waste across all years in the database lack a reported final destination. Spatially explicit cradle-to-grave reporting for waste handling from both conventional and unconventional oil and gas development is important to assess a number of environmental and human health hazards and risks of oil and gas development and associated operations and practices.

Abstract:
There is a need for the development of effective baselines against which the water quality impacts of industry in general, and shale gas extraction specifically, can be assessed. The salinity, and hence the specific conductance, of fluids associated with shale gas extraction is typically many times higher that of river water. The contrast between these two water types means that testing for salinity (specific conductance) could provide an ideal sentinel for detecting environmental impact of shale gas extraction. Here, Bayesian generalised linear modelling was used to predict specific conductance across English surface waters. The modelling used existing, spot-sampled data from 2005 to 2015 from 123 sites to assess whether this approach could predict variation for subsequent years or for a new site (data from 2002 to 2015). We show that the results were readily projected in to subsequent years for sites included in the initial analysis. The use of covariates (land-use, hydroclimatic and soil descriptors) did not prove useful in predicting specific conductance at further sites not previously included in the analysis. The extension of the approach to 6833 English river monitoring sites with 10 or more observations from more than one year over the period 2005–2015 showed that it was possible to reproduce the seasonal variation in river water specific conductance. The approach taken here shows that it is possible to use low-frequency but widespread monitoring data to predict natural variation at monitoring sites to give a probabilistic assessment of whether or not a pollution incident has occurred and the seasonal variation, expressed as uncertainty bounds around the observations, at a specific site has been exceeded.

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Recovery of natural gas and oil from unconventional (shale) reservoirs relies on horizontal drilling and hydraulic fracturing to make it economical. Hydraulic fracturing generates vast quantities of flowback and produced water (FPW) and its composition exhibits huge spatial and temporal variations among shale plays. This review focuses on the characteristics and management of wastewaters originating for oil and gas extraction. Wastewater characteristics, including the quantity and chemical composition of the FPW, are discussed. The future of unconventional oil and gas industry hinges on effective management of FPW. Membrane technologies have the potential to offer solutions to sustainable reuse of this water resource. The performance of a range of membrane processes is evaluated and compared. Emerging membrane-based technologies employed in similar fields are also discussed. The results in peer-reviewed publications could offer a guide for the selection of appropriate technologies based on the desired application. Membrane fouling, lack of pilot- and full-scale experience and high energy consumption are primary challenges for membrane applications in FPW. Then challenges and future research needs are addressed, advances in membrane materials, systematic analyses of organics and electric generation from salinity gradient are promising approaches to address the issues.

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Today's 'fracking debate' includes a familiar set of actors and arguments. Advocates of unconventional oil and gas production contend that it has contributed to an economic renaissance for many subnational governments and has improved American energy security. Opponents suggest that unconventional production is an environmental and public health hazard. One way that states are trying to balance the economic benefits of continued energy production with environmental protection is through the use of information disclosure requirements. Prior work notes that the rigor of state disclosure standards relative to unconventional oil and gas production vary. Through measures of association and exact logistic regression, this project expands the disclosure literature by focusing on three types of disclosure: pre-drilling notification, chemical disclosure during operations, and trade secret exemptions.

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We developed an integrated treatment train that enables effective treatment of shale oil and gas produced water generated from the Wattenberg field in northeast Colorado. Membrane distillation (MD) was performed in tandem with simple and inexpensive pretreatment steps, namely precipitative softening (PS) and walnut shell filtration (WSF). PS removed various particulate, organic, and inorganic foulants, thereby mitigating fouling and scaling potential of the produced water. WSF displayed exceptional efficiencies (≥95%) in eliminating volatile toxic compounds including benzene, ethylbenzene, toluene, and xylenes (BTEX) along with additional gasoline and diesel range organic compounds. With pretreatment, the water vapor flux of MD decreased by only 10% at a total water recovery of 82.5%, with boron and total BTEX concentrations in the MD distillate meeting the regulatory requirements for irrigation and typical discharge limits, respectively. The use of pretreatment also led to robust membrane reusability within three consecutive treatment cycles, with MD water flux fully restored after physical membrane cleaning. Our results highlight the necessity of pretreatment prior to MD treatment of produced water and demonstrate the potential of our treatment train to achieve a cost-effective and on-site wastewater treatment system that improves the sustainability of the shale oil and gas industry.

Abstract:
Forward osmosis (FO) and membrane distillation (MD) are emerging technologies of interest for the treatment of high salinity brines. In this study, we aim to demonstrate the feasibility of an integrated FO-MD system for water recovery from high salinity produced waters obtained from shale gas extraction facilities. In the proposed hybrid system, FO draws water from high salinity feed, while MD regenerates the diluted FO draw solution. We show that this process integration can combine the advantages of both processes; low fouling tendency, possibility of using low-grade waste heat as the main energy source and high quality permeate. We further integrate the FO-MD system with an electrocoagulation (EC) system as pretreatment and show stable performance with minimal fouling. EC removed total organic carbon and total suspended solids by up to 78% and 96%, respectively. We studied the impact of experimental conditions (temperature, flow velocity and draw solution concentration) on performance of the integrated system in short-term experiments. In addition, we conducted long-term experiments using two different produced waters. We show that to achieve continuous high recovery with maximized water flux, a combination of two MD membranes can provide a viable solution.

Abstract:
Unconventional natural gas (UNG) refers to a suite of technologies that aid in the exploration, extraction, and transportation of natural gas resources. This paper reports on the results of a scoping review examining peer-reviewed articles published between 2009–2018 on the impacts of UNG activities on communities located across the supply chain (i.e. “upstream” communities adjacent to the point of gas extraction, “midstream” communities located near pipelines, and “downstream” communities that are cooling natural gas into liquid form for international export). Our review identified 523 articles, 68% of which focused on the United States. The majority of articles (77%) highlighted community impacts adjacent to the point of extraction, with only 11% and 6% addressing midstream and downstream supply chain impacts. Results classified 28 unique types of community impacts conceptualized within the literature, organized into four categories: environmental impacts; impacts to infrastructure and service delivery; impacts on policy, regulation and participation in decision-making; and socioeconomic impacts. We provide a narrative review to clarify the socioeconomic impacts and possible policy mitigation efforts across the UNG supply chain.

Abstract:
Objectives To examine relationships between short-term and long-term exposures to unconventional natural gas development, commonly known as fracking, and county hospitalization rates for a variety of broad disease categories. Study design This is an ecological study based on county-level data for Pennsylvania, United States, 2003–2014. Methods We estimated multivariate regressions with county and year fixed effects, using two 12-year panels: all 67 Pennsylvania counties and 54 counties that are not large metropolitan. Results After correcting for multiple comparisons, we found a positive association of cumulative well density (per km2) with genitourinary hospitalization rates. When large metropolitan counties were excluded, this relationship persisted, and positive associations of skin-related hospitalization rates with cumulative well count and well density were observed. The association with genitourinary hospitalization rates is driven by females in 20–64 years group, particularly for kidney infections, calculus of ureter, and urinary tract infection. Contemporaneous wells drilled were not significantly associated with hospitalizations after adjustment for multiple comparisons. Conclusions Our study shows that long-term exposure to unconventional gas development may have an impact on prevalence of hospitalizations for certain diseases in the affected populations and identifies areas of future research on unconventional gas development and health.

Abstract:
Colloids and organics in shale gas fracturing flowback water (SGFFW) during shale gas extraction are of primary concerns. Coagulation combined with oxidation might be a promising process for SGFFW treatment. In this study, a novel electrocoagulation-peroxone (ECP) process was developed for SGFFW treatment by simultaneous coagulation and oxidation process with a Al plate as the anode and a carbon-PTFE gas diffusion electrode as the cathode, realizing the simultaneous processes of coagulation, H2O2 generation and activation by O3 at the cathode. Compared with electrocoagulation (EC) and peroxi-electrocoagulation (PEC), COD removal efficiency mainly followed the declining order of ECP, PEC and EC under the optimal current density of 50 mA cm−2. The appearance of medium MW fraction (1919 Da) during ozonation and PEC but disappearance in ECP indicated that these intermediate products couldn't be degraded by ozonation and PEC but could be further oxidized and mineralized by the hydroxyl radical produced by the cathode in ECP, demonstrating the hydroxyl radical might be responsible for the significant enhancement of COD removal. The pseudo-first order kinetic model can well fit ozonation and EC process but not the PEC and ECP process due to the synthetic effect of coagulation and oxidation. However, the proposed mechanism based model can generally fit ECP satisfactorily. The average current efficiency for PEC was 35.4% and 12% higher than that of ozonation and EC, respectively. This study demonstrated the feasibility of establishing a high efficiency and space-saving electrochemical system with integrated anodic coagulation and cathodic electro-peroxone for SGFFW treatment.

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Abstract:
Shale gas exploitation is booming in China. Unlike the traditional oil extraction industry, shale gas extraction will generate more solid waste. Water-based drill cuttings (WBDC) as one of them is currently under regulatory vacuum. This article studied the status of heavy metal pollution and evaluated the ecological risk of WBDC. Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn were selected for the study. The results showed that except for Ni, other heavy metals showed different degrees of pollution, but the leaching toxicity was rather limited. Meanwhile, the ecological risks of all samples were significant, which posed a huge threat to environment. Though its limitation, this article can provide theoretical foundation for regulatory decisions of WBDC.

Abstract:
Unconventional oil and gas (UOG) development has increased dramatically in the Marcellus Shale region over the past decade, and there is widespread public concern about the potential effects that UOG development may have on water quality. The goal of this study was to assess whether a suite of stream water quality constituents was related to the intensity of UOG development in corresponding catchments. Nineteen streams in southwestern Pennsylvania, where UOG development is prevalent, and 10 streams in western Maryland, where no UOG development has occurred, were sampled in summer 2013. Dissolved metals, radium isotopes, radon, specific conductance, stream discharge, and pH were measured. Principal component analysis revealed that samples tended to cluster by state, but some overlap in water quality existed between Maryland and Pennsylvania. Linear models were used to assess how response variables were related to UOG, other extractive activities, and landscape characteristics. These models showed that an index of oil and gas development had significant explanatory power for specific conductance, As, Ca, K, Mg, Na, and Sr. Other land use and land cover variables, such as forest, urban development, and coal mining, as well as stream discharge and pH, also were significantly associated with response variables. These results suggest that, in the Marcellus Shale region, UOG may elevate specific conductance and dissolved element concentrations in streams, but it should be considered in the context of broader patterns of land use and human activity.

Abstract:
The fracking industry faces various challenges although technologies have been advanced in the hydraulic fracturing and horizontal drilling. Treatment for the water used after the fracking process is one of the key issues preventing hydraulic fracturing from being widely implemented. Especially the chemicals that are used for various purposes during fracking remain in the water that flows back to the surface. Reports have been seen that the problematic chemicals used in the fracking process cause HSE (Health, Safety and Environment) issues. Before any chemical used in the fracking is eliminated or replaced with alternatives, its greenness should be evaluated. A tool called Greenness Index was used in this study to evaluate several typical chemicals used in the current fracking process. SDS (Safety Data Sheet) information was used by Greenness Index to assess the chemicals. It was found that with similar amount of SDS information available, citric acid is relatively greener than ammonium persulfate. SDS information of guar gum is less than that of citric acid and ammonium persulfate, but the evaluation for guar gum still indicates that it is a green chemical based on the limited data from its SDS. When more information with respect to how they behave during the fracking process is available, Greenness Index can provide more comprehensive evaluations.

Abstract:
The selection of an appropriate draw solution is crucial to the successful implementation of desalination for the treatment of highly saline fracking wastewaters via the forward osmosis (FO) process. In this report, four organic compounds (potassium acetate, potassium formate, sodium glycolate, and sodium propionate) were identified as candidate draw solutes for the first time for desalination of fracking wastewater by FO. Higher average FO water fluxes were achieved for the identified organic draw solutions (10.50–13.26 LMH for synthetic fracking wastewater and 19.05–24.05 LMH for real fracking wastewater) compared to commonly used draw solution, NaCl (average FO water flux: 8.25 LMH for synthetic fracking wastewater and 14.44 LMH for real fracking wastewater). Higher average FO water fluxes were obtained due to likely lower reverse salt fluxes for the organic draw solutions compared to NaCl. Higher FO water fluxes were achieved for the real fracking wastewater, as compared to the synthetic wastewater, due to higher osmotic pressure differences between feed and draw solutions. Membrane distillation could be used as a downstream separation technique in the FO process for recycling of the identified draw solutes.

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Water generated by hydraulic fracturing for the production of oil and gas, commonly termed ‘produced water’, may contain residual organic compounds from the fracturing process or the subsurface formation. Biological treatment is a potential technology to remove residual organic compounds in produced water. Biocides are often added to both fracturing fluids and produced water to limit undesirable microbiological activity, and glutaraldehyde is the most commonly used biocide in hydraulic fracturing. Residual biocides in produced water can limit biological treatment efficiency. We evaluated the effect of glutaraldehyde on the biodegradation of five of the most commonly reported organic compounds in hydraulic fracturing fluids in an engineered biofilm treatment. Our results demonstrated that glutaraldehyde delays biological organic compound removal by introducing a biodegradation lag phase. In addition, the effects of glutaraldehyde were more pronounced for more rapidly degraded compounds. Finally, the presence of glutaraldehyde did not decrease microbial abundance nor drive microbial community structure, suggesting that observed effects were due to altered microbial activity. These results highlight the necessity to consider co-contaminant interactions during treatment of complex waste streams where residual biocide may be present.

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Unconventional gas development can bring rapid change to local communities who often have limited resources and capacity to deal with them. To focus limited resources and capacities, it is essential to identify the underlying factors which are most important for maintaining perceptions of community wellbeing and resilience in different phases of development. Little extant research identifies how these factors may change over different industry phases (cf. boom-bust cycles). This paper identifies important factors for subjective community wellbeing and resilience in the construction and post-construction phases of unconventional gas development in the Western Downs region of rural Queensland, Australia. Survey data from 400 residents in 2014 and 400 in 2016 were used to examine changes in subjective community wellbeing and resilience between these phases. The most important dimensions underlying community wellbeing in both phases were perceptions of “services and facilities” and “community spirit, cohesion and trust”, with the latter more important in the construction phase. The most important community issues relating to community resilience were perceptions of environmental management, which was unfavourable in both phases, and perceived economic opportunities, which become unfavourable in the post-construction or early operations phase. Subjective evaluations of community planning, leadership and information sharing around responses to unconventional gas development were also seen as limited in local communities. Additionally, communities did not feel heard and there was a lack of trust in industry and government. Finally, this paper discusses implications of these findings. Enhancing services and facilities is an important and relatively straightforward way of enhancing subjective community wellbeing being and resilience. However, community spirit, cohesion, and trust are equally important, though perhaps not given the same emphasis in social investment plans. Concerns about environmental management persist across both phases and local communities need to prepare for a decline in economic activity after the construction phase.

Abstract:
The prospect of unconventional shale gas development in the semi-arid Karoo Basin (South Africa) has created the prerequisite to temporally characterise the natural radioactivity in associated groundwater which is solely depended on for drinking and agriculture purposes. Radon (222Rn) was the primary natural radionuclide of interest in this study; however, supplementary radium (226Ra and 228Ra) in-water measurements were also conducted. A total of 53 aquifers spanning three provinces were studied during three separate measurement campaigns from 2014 to 2016. The Karoo Basin's natural radon-in-water levels can be characterised by a minimum of 1 ± 1 Bq/L (consistent with zero or below LLD), a maximum of 183 ± 18 Bq/L and mean of 41 ± 5 Bq/L. The mean radon-in-water levels for shallow aquifers were systematically higher (55 ± 10 Bq/L) compared to deep (14 ± 3 Bq/L) or mixed aquifers (20 ± 6 Bq/L). Radon-in-water activity concentration fluctuations were predominantly observed from shallow aquifers compared to the generally steady levels of deep aquifers. A collective seasonal mean radon-in-water levels increase from the winter of 2014 (44 ± 8 Bq/L) to winter of 2016 (61 ± 16 Bq/L) was noticed which could be related to the extreme national drought experienced in 2015. Radium-in-water (228Ra and 226Ra) levels ranged from below detection level to a maximum of 0.008 Bq/L (226Ra) and 0.015 Bq/L (228Ra). The 228Ra/226Ra ratio was characterized by a minimum of 0.93, a maximum of 6.5 and a mean value of 3.3 ± 1.3. Developing and improving baseline naturally occurring radionuclide groundwater databases is vital to study potential radiological environmental impacts attributed to industrial processes such as hydraulic fracturing or mining.

Abstract:
Natural gas production in the United States has increased rapidly over the past decade, along with concerns about methane (CH4) fugitive emissions and its climate impacts. Quantification of CH4 emissions from oil and natural gas (O&NG) operations is important for establishing scientifically sound policies for mitigating greenhouse gases. We use the aircraft mass balance approach for three flight experiments in August and September 2015 to estimate CH4 emissions from O&NG operations over the southwestern Marcellus Shale. We estimate a mean CH4 emission rate as 21.2 kg/s with 28% coming from O&NG operations. The mean CH4 emission rate from O&NG operations was estimated to be 1.1% of total NG production. The individual best‐estimate emission rates from the three flight experiments ranged from 0.78 to 1.5%, with overall limits of 0% and 3.5%. These emission rates are at the low end of other top‐down studies, but consistent with the few observational studies in the Marcellus Shale region as well as the U.S. Environmental Protection Agency CH4 inventory. A substantial source of CH4 (~70% of observed CH4 emissions) was found to contain little ethane, possibly due to coalbed CH4 emitted either directly from coal mines or from wells drilled through coalbed layers in O&NG operations. Recent regulations requiring capture of gas from the completion‐venting step of hydraulic fracturing appear to have reduced the atmospheric release of CH4. Our study suggests that for a 20‐year time scale, energy derived from the combustion of natural gas extracted from this region likely exerts a net climate benefit compared to coal.

Abstract:
Applications for exploratory shale gas development via hydraulic fracturing (fracking) have raised concern about energy development impacts in South Africa. Initially, focus was on the arid Karoo, but interest now includes KwaZulu-Natal, a populous, agricultural province with high cultural, ecological, and economic diversity. We conducted focus groups and an online survey to determine how some South Africans perceive fracking. Focus group participants were unanimous in their opposition, primarily citing concerns over water quality and rural way-of-life. The survey confirmed broad consistency with focus group responses. When asked which provinces might be affected by fracking, KwaZulu-Natal ranked behind provinces in the Karoo, suggesting an awareness bias towards Karoo projects. Frequently-identified concerns regarding Agriculture and Natural Resources were Reduced quality of water, Negative impacts to ecosystems and natural biodiversity, Reduced quantity of water, and Pollution hazards. Frequent concerns regarding Social, Cultural, and Local Community issues were Impacts to human health, Visual/aesthetic degradation of tourism areas, Degradation of local infrastructure, and Physical degradation of tourism sites. Most survey respondents were pessimistic about potential benefits of fracking to South Africa’s domestic energy supply, and did not agree fracking would reduce negative impacts of coal mining or create jobs. Survey respondents were pessimistic about government’s preparedness for fracking and agreed fracking created opportunity for corruption. Many respondents agreed they would consider fracking when voting, and identified needs for more research on fracking in South Africa, which focused heavily on environmental impacts, especially water, in addition to the welfare of local citizens and their communities.

Abstract:
Two traditional pretreatment methods were adopted for the pretreatment of shale gas produced water in view of facilitation for subsequent treatment processes. The research was focused on alkali precipitation due to its better performance on shale gas produced water pretreatment compared with flocculation. Agitating time, settling time, stirring speed, dosage of coagulant aids were determined by optimal configuration. The results showed that adding together with 1.0 g/L NaOH and 2.0 g/L Na2CO3 under 200 rpm stirring for 5 min and after 30 min settling, suspended solids (SS) in the effluent could drop below 20 mg/L and concentration of hardness ion could be less than 150 mg/L, which was well met the water quality to facilitate the following single or multiple-effect evaporation. The optimized alkaline pretreatment method towards produced water had excellent adaptability and practicability with economic cost and easy operation. It had significant potential and could be widely used in the shale gas produced water pretreatment process.

Abstract:
We introduce the new concept of embodied energy injustices in order to encourage integrative, systemic, transboundary assessment of the global implications and responsibility of energy-policy decisions. Embodied energy injustices reframe considerations of energy justice to explicitly consider hidden and distant injustices (upstream or downstream) arising from the extraction, processing, transportation and disposal of energy resources. We assess the embodied energy injustices connected to the decision to decommission a coal-fired power plant in Salem, Massachusetts, US, and its replacement with a natural-gas-fired power station. Cerrejón open-pit coalmine in La Guajira, Colombia, powered the Salem plant for over a decade. Fracked gas from Pennsylvania now supplies fuel for the new power station. Comparing the extraction of these two very different fuels reveals multiple parallel injustices. But the regulatory environment fails to account for the different constituencies, jurisdictions and effects that fall outside the formal remit of existing impact assessments. We therefore call for mandatory transboundary impact assessments of large-scale energy-related projects, which explicitly integrate previously unrecognized social-environmental harms and injustices. Expanding energy law and policy discussions to incorporate embodied energy injustices can enhance sustainable energy governance and enable corporate accountability for the transboundary harms of fossil fuel extraction and use. Linking chains of energy injustice—by revealing their interconnected positions along fossil-fuel supply chains—may help generate and unite powerful trans-local solidarity movements, which politicize local struggles within wider national, regional and global energy politics.

Abstract:
The potential water demand for fracturing fluids along with the possible flowback and produced water production is assessed for the Dutch Posidonia shale. Total water demand estimated for 25 years of the field development using historic data from the U.S. plays varies between 12.2 and 36.9 Mm3. The maximal annual water consumption of 0.95–2.88 Mm3 is expected in the peak years of shale gas production. These figures are much lower than the availability of any potential water sources, which include drinking water, fresh and brackish groundwater, river water, effluents of wastewater treatment plants (WWTP) and sea water. River water is considered the most promising water source for fracturing fluids in the Dutch Posidonia shale based on its availability (>6·104 Mm3/year) and quality (only bacterial composition needs to be controlled). Total wastewater production for the whole period of the field development is estimated between 6.6 and 48.0 Mm3. Wastewater recycling can cover significant part of the source water demand for fracturing fluid. However, high mineral content of the wastewater as well as temporal and spatial discrepancies between wastewater production and water demand will form obstacles for wastewater recycling. The assessment framework developed in this study may be applied for other shale gas fields with high uncertainties regarding subsurface properties, connate formation water characteristics and future legislative framework.

Abstract:
Approaching behaviour that produces environmental harm through the medium of criminal sanctions (largely involving monetary penalties) has been criticised consistently as failing to prevent environmental crimes and harms, and failing to concurrently reduce environmental re-offending. Furthermore, important state–corporate political and economic relationships exist that ensure the continuation of environmental degradation. We suggest that a way to overcome this is to re-work the current legal system to one grounded in Earth jurisprudence. Although we realise that state–corporate relationships would likely prevent the implementation of Earth jurisprudential principles, we argue such principles are essential to up-end the prioritisation of economic imperatives over ecological values within capitalist societies. To demonstrate the strength and utility of the Earth jurisprudential approach, we use the case of fracking for shale gas in the United Kingdom to examine how Earth jurisprudential principles could prevent environmental harm from occurring.

Abstract:
Over the past decade, increases in high-volume hydraulic fracturing for oil and gas extraction in the United States have raised concerns with residents living near wells. Flaring, or the combustion of petroleum products into the open atmosphere, is a common practice associated with oil and gas exploration and production, and has been under-examined as a potential source of exposure. We leveraged data from the Visible Infrared Imaging Spectroradiometer (VIIRS) Nightfire satellite product to characterize the extent of flaring in the Eagle Ford Shale region of south Texas, one of the most productive in the nation. Spatiotemporal hierarchical clustering identified flaring sources, and a regression-based approach combining VIIRS information with reported estimates of vented and flared gas from the Railroad Commission of Texas enabled estimation of flared gas volume at each flare. We identified 43,887 distinct oil and gas flares in the study region from 2012-2016, with a peak in activity in 2014 and an estimated 4.5 billion cubic meters of total gas volume flared over the study period. A comparison with well permit data indicated the majority of flares were associated with oil-producing (82%) and horizontally-drilled (92%) wells. Of the 49 counties in the region, 5 accounted for 71% of the total flaring. Our results suggest flaring may be a significant environmental exposure in parts of this region.

Abstract:
The 2017 Texas Water Development Board's State Water Plan predicts a 41% gap between water demand and existing supply by 2070. This reflects an overall projection, but the challenge will affect various regions of the state differently. Texas has 16 regional water planning zones characterized by distinct populations, water demands, and existing water supplies. Each is expected to face variations of pressures, such as increased agricultural and energy development (particularly hydraulic fracturing) and urban growth that do not necessarily follow the region's water plan. Great variability in resource distribution and competing resource demands across Texas will result in the emergence of distinct hotspots, each with unique characteristics that require multiple, localized, interventions to bridge the statewide water gap. This study explores three such hotspots: 1) water-food competition in Lubbock and the potential of producing 3 billion gallons of treated municipal waste water and encouraging dryland agriculture; 2) implementing Low Impact Developments (LIDs) for agriculture in the City of San Antonio, potentially adding 47 billion gallons of water supply, but carrying a potentially high financial cost; and 3) water-energy interrelations in the Eagle Ford Shale in light of well counts, climate dynamics, and population growth. The growing water gap is a state wide problem that requires holistic assessments that capture the impact on the tightly interconnected water, energy, and food systems. Better understanding the trade-offs associated with each ‘solution’ and enabling informed dialogue between stakeholders, offers a basis for formulating localized policy recommendations specific to each hotspot.

Abstract:
Accidental spills and surface discharges of shale gas produced water could contaminate water resources and generate health concerns. The study explored the formation and speciation of disinfection by-products (DBPs) during chlorination of natural waters under the influence of shale gas produced water. Results showed the presence of produced water as low as 0.005% changed the DBP profile measurably. A shift to a more bromine substitution direction for the formation of trihalomethanes, dihaloacetic acids, trihaloacetic acids, and dihaloacetonitriles was illustrated by exploring the individual DBP species levels, bromine substitution factors, and DBP species fractions, and the effect was attributable to the introduction of bromide from produced water. The ratio of dichloroacetic and trichloroacetic acids also increased, which was likely affected by different bromination degrees at elevated bromide concentrations. Increasing blend ratios of produced water enhanced the formation of DBPs, especially the brominated species, while such negative effects could be alleviated by pre-treating the produced water with ozone/air stripping to remove bromide. The study advances understandings about the impacts of produced water spills or surface discharges regarding potential violation of Stage 2 DBP rules at drinking water treatment facilities.

Abstract:
Wastewater recovered from hydraulic fracturing is referred to as flowback and produced water (FPW), and is often saline, contains numerous organic and inorganic constituents, and may pose threats to groundwater resources. Hundreds of spills of FPW have been reported to the Alberta Energy Regulator each year. Recently, samples of FPW derived from hydraulic fracturing of the Duvernay Formation, AB, were found to contain a previously unidentified class of aryl phosphates, including diphenyl phosphate (DPP), triphenyl phosphate (TPP), and others. Aryl phosphates are also used in a variety of other industries and their constituents can be found in flame retardants, plasticizers, lubricants, hydraulic fluids, and oxidizers. Many of these aryl phosphates break down into DPP. Therefore, it is important to determine the environmental fate and potential impact of DPP if spilled in the near-surface, as DPP is an emerging contaminant in soil and groundwater systems. This study was aimed at determining 1) the sorption behavior of DPP onto various surficial sediments collected within the Fox Creek, AB region, and 2) the toxicity of DPP toward aquatic ecosystems. We report that the sorption of DPP onto both clay-rich soils and sandy sediment was low compared to that of other aryl phosphates, with an average log KOC value of 2.30 ± 0.42 (1σ). Therefore, the transport of DPP in groundwater would be rapid due to its low degree of sorption on surficial materials. We also determined the acute 96 h-LC50 of DPP on zebrafish embryos to be 50.0 ± 7.1 mg/L. Su et al. (2014) studied the toxic effects of DPP and TPP on chicken embryonic hepatocytes and found that DPP had less cytotoxic effects than TPP but altered more gene transcripts. From the results our study, we infer that DPP may pose an environmental risk to aquatic ecosystems if released into the environment.

Abstract:
The primary challenges of petroleum industries are to provide a secure quantity and quality of water resources and how to manage the generated wastewater adequately. Appropriate application of water treatment systems would play a substantial role in drilling operations. Therefore, wastewater management and controlling the amount of produced hazardous materials should be significantly taken into consideration. The objective of this extensive study is to calculate the required water for the waterflooding, polymer flooding, and hydraulic fracturing performances, and subsequently, the percentage of fresh water saving in a shale oil reservoir was calculated accordingly. First of all, the required water and treated water for each well were calculated, and then, the percentage of saving water was averagely calculated. As a result, the percentage of fresh water saving for waterflooding, polymer flooding, and hydraulic fracturing were 71.5%, 70%, and 83.7%, respectively. It was indicated that most of the injected water was treated again and reinjected in the fracturing operations. Furthermore, the total volume of required water for the drilling of Pazanan oilfield’s wells was approximately 125 million gallons that indicated the treatment processes provided about 95 million gallons of this volume. Consequently, the average volume of fresh water saving was relatively 70% which was clarified the accuracy of wastewater separation and purification in the treatment system.

Abstract:
The objective of this study is to evaluate the public water contamination in the cities of Midland and Odessa, West Texas. Even though both cities are geographically close, their sources of water for public use are different. For this study, the copper-, lead-, arsenic-, nitrate-, and chromium-level reports in drinking water, provided by the cities from 2008 to 2017, were organized and analyzed using Cubic Hermite Interpolation. The results for each contamination per city were compared and contrasted with the Environmental Protection Agency (EPA) standards. Also, this study proposed possible risks to human health, as well as potential origins of the pollutants. Finally, conclusions about the quality of water for human consumption and possible reasons behind the difference of results between the 2 cities were made.

Abstract:
This paper seeks to expand an emerging, multi-disciplinary body of work about tradeoffs in the agriculture-oil and gas nexus by offering evidence of the ways that farm and ranch operators experienced and negotiated costs and benefits of hosting oil and gas in three U.S. oil and gas plays. We report results of mail survey sent to landowners in four rural counties in three U.S. oil and gas regions (Marcellus, Powder River Basin and Bakken) and specifically data from farmers and ranchers about perceptions and experiences of the agriculture-oil and gas nexus (n = 96). The data provided through closed- and open-ended questions suggest, from the perspective of those hosting energy infrastructure on farms and ranches, oil and gas development has enhanced agriculture operations and rural livelihoods but is not without negative impacts or tradeoffs. We introduce the balancing act as a useful framework for considering tradeoffs associated with hosting extractive industries as it allows space for the “balance” between economic activities to be impossible, aspirational or achievable. The study observes that mechanisms through which positive and negative effects operate vary according to agricultural context. Implications for research and practice in the agriculture-energy nexus are discussed.

Abstract:
A systematic method was used to review the existing epidemiologic literature and determine the state of the scientific evidence for potential adverse health outcomes in populations living near oil and natural gas (ONG) operations in the United States. The review utilized adapted systematic review frameworks from the medical and environmental health fields, such as Grading of Recommendations, Assessment, Development and Evaluations (GRADE), the Navigation Guide, and guidance from the National Toxicology Program’s Office of Health Assessment and Translation (OHAT). The review included 20 epidemiologic studies, with 32 different health outcomes. Studies of populations living near ONG operations provide limited evidence (modest scientific findings that support the outcome, but with significant limitations) of harmful health effects including asthma exacerbations and various self-reported symptoms. Study quality has improved over time and the highest rated studies within this assessment have primarily focused on birth outcomes. Additional high-quality studies are needed to confirm or dispute these correlations.

Abstract:
While New York has banned fracking, new and expanded natural gas pipelines are being constructed across the state. Our previous studies have reported that compressor stations are a major source of air pollution at fracking sites. We have used two federal datasets, the U.S. Environmental Protection Agency’s (EPA) National Emissions Inventory and Greenhouse Gas Inventory, to determine what is known concerning emissions from the compressor stations along natural gas pipelines in the state. From a total of 74 compressor stations only 18 report to EPA on emissions. In the seven year period between 2008 and 2014 they released a total of 36.99 million pounds of air pollutants, not including CO2 and methane. This included emissions of 39 chemicals known to be human carcinogens. There was in addition 6.1 billion pounds of greenhouse gases release from ten stations in a single year. These data clearly underestimate the total releases from the state’s natural gas transportation and distribution system. However, they demonstrate significant releases of air pollutants, some of which are known to cause human disease. In addition, they release large amounts of greenhouse gases that contribute to climate change.

Abstract:
Recent studies of unconventional resource development (URD) and adverse health effects have been limited by distance-based exposure surrogates. Our study compared exposure classifications between air pollutant concentrations and "well activity" (WA) metrics, which are distance-based exposure proxies used in Marcellus-area studies to reflect variation in time and space of residential URD activity. We compiled Pennsylvania air monitoring data for benzene, carbon monoxide, nitrogen dioxide, ozone, fine particulates and sulfur dioxide, and combined this with data on nearly 9000 Pennsylvania wells. We replicated WA calculations using geo-coordinates of monitors to represent residences and compared exposure categories from air measurements and WA at the site of each monitor. There was little agreement between the two methods for the pollutants included in the analysis, with most weighted kappa coefficients between -0.1 and 0.1. The exposure categories agreed for about 25% of the observations and assigned inverse categories 16%-29% of the time, depending on the pollutant. Our results indicate that WA measures did not adequately distinguish categories of air pollutant exposures and employing them in epidemiology studies can result in misclassification of exposure. This underscores the need for more robust exposure assessment in future analyses and cautious interpretation of these existing studies.

Abstract:
Shale oil and gas extraction technology has caused a large shift in the United States' energy landscape over the last decade. This had a wide range of impacts on rural communities mostly in which oil and gas extraction occurs. While many studies have focused on the economic and environmental impact of shale development, researchers have only begun to study the social changes brought on by the shale resource extraction. We examine the influence of shale oil and gas employment as a share of overall county employment on county marriage, divorce, and cohabitation rates. We find evidence that oil and gas employment growth is associated with decreased marriage rates and increased divorce rates from 2009 to 2014. We test several channels through which oil and gas development may influence marriage behaviors and find that changes in female labor force participation, county sex ratios, and median household incomes are associated with oil and gas development. We also test for differences across the rural/urban continuum and find that our results are largely driven by nonmetro counties.

Abstract:
Recent studies show conflicting estimates of trends in methane (CH4) emissions from oil and natural gas (ONG) operations in the U.S. We analyze atmospheric CH4 measurements from 20 North American sites in the NOAA Global Greenhouse Gas Reference Network and determined trends for 2006-2015. Using CH4 vertical gradients as an indicator of regional surface emissions, we find no significant increase in emissions at most sites and modest increases at three sites heavily influenced by ONG activities. Our estimated increases in North American ONG CH4 emissions (on average 3.4 ± 1.4 % yr-1 for 2006-2015, ±σ) are much smaller than estimates from some previous studies and below our detection threshold for total emissions increases at the east coast sites that are sensitive to U.S. outflows. We also find an increasing trend in ethane/methane emission ratios which has resulted in major overestimation of oil and gas emissions trends in some previous studies.

Abstract:
Data collected from random samples of residents and absentee landowners in two counties in the Eagle Ford Shale region of South Texas were used to examine the perceptions regarding influence, inclusion, and trust of local leaders and other stakeholders in the area. Additionally, two hypotheses pertaining to the association between individuals’ perceptions of inclusion by local governments—both city and county—and individuals’ levels of trust in those governments as sources of information about the positive and negative impacts of shale oil and/or natural gas development were tested and supported. Substantive descriptive and statistical analyses are reported.