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1.
Environ Pollut ; 272: 116411, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33486299

RESUMO

Hydraulic fracturing has become widely used in recent years to access vast global unconventional sources of oil and gas. This process involves the injection of proprietary mixtures of water and chemicals to fracture shale formations and extract the hydrocarbons trapped within. These injection fluids, along with minerals, hydrocarbons, and saline waters present within the formations being drilled into, return to the surface as flowback and produced water (FPW). FPW is a highly complex mixture, containing metals, salts and clay, as well as many organic chemicals, including polycyclic aromatic hydrocarbons such as phenanthrene. The present study sought to determine the effects of temperature on the accumulation of phenanthrene in rainbow trout (Oncorhynchus mykiss). This model organism resides in rivers overlapping the Montney and Duvernay formations, both highly developed formations for hydraulic fracturing. Rainbow trout acclimated to temperatures of 4, 13 and 17 °C were exposed to either 5% or 20% FPW, as well as saline mixtures representing the exact ionic content of FPW to determine the accumulation of radiolabelled 14C phenanthrene within the gill, gut, liver and gallbladder. FPW exposure reduced the overall accumulation of phenanthrene in a manner most often similar to high salinity exposure, indicating that the high ionic strength of FPW is the primary factor affecting accumulation. Accumulation was different at the temperature extremes (4 and 17 °C), although no consistent relationship was observed between temperature and accumulation across the observed tissues. These results indicate that several physiological responses occur as a result of FPW exposure and water temperature change which dictate phenanthrene uptake, particularly in the gills. Temperature (and seasonality) alone cannot be used to model the potential accumulation of polycyclic aromatic hydrocarbons after FPW spills.


Assuntos
Fraturamento Hidráulico , Oncorhynchus mykiss , Fenantrenos , Poluentes Químicos da Água , Animais , Temperatura , Água , Poluentes Químicos da Água/análise
2.
Chemosphere ; 262: 127968, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182104

RESUMO

Electrocoagulation (EC) coupled with E-peroxone process (ECP) was a promising and cost-effective integrated technology for shale gas fracturing flowback water (SGFFW) treatment. In this study, the ECP process was comprehensively compared with two sequential processes (EC followed by E-peroxone (EC-E-peroxone) and E-peroxone followed by EC (E-peroxone-EC)) to elucidate the synergistic effect of this coupled process. In EC-E-peroxone process, COD decreased by 89.2%, while COD decreased by 82.5% for 180 min in E-peroxone-EC process. However, COD removal efficiency was 82.4% in ECP for only 90 min. Average current efficiency of the ECP process was 29.9%, which was twice than that of the sequential processes. The enhancement factor was calculated to be 1.63, demonstrating the substantial significant synergistic effects for ECP. Only low MW components could be observed for the EC-E-peroxone (average MW = 533 Da with PD ≈ 1) and ECP process (MW = 538 Da with PD ≈ 1). These results suggested that EC-E-peroxone and ECP process had much stronger oxidation ability, demonstrating the enhancement of OH production induced by the Al-based coagulants might be responsible for the significant enhancement of COD removal. These results indicated there could be a synergistic effect between EC and ozone in addition to EC and E-peroxone reactions. Compared to the two sequential processes, ECP was a high efficiency and space-saving electrochemical system with simultaneous coagulation and enhanced OH generation by the products of anode and the cathode.


Assuntos
Técnicas Eletroquímicas/métodos , Peróxido de Hidrogênio/química , Gás Natural/análise , Ozônio/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Análise da Demanda Biológica de Oxigênio , China , Eletrodos , Floculação , Fraturamento Hidráulico , Oxirredução , Águas Residuárias/química
3.
J Environ Radioact ; 228: 106522, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33360557

RESUMO

In recent years, radium has attracted considerable attention primarily because of the rapid increase in unconventional (fracking) drilling technology in the United States and around the world. One of the major radionuclides of interest in unconventional drilling wastes is radium isotopes (224Ra, 226Ra, 228Ra). To access long-term risks associated with radium isotopes entering into the environment, accurate measurements of radium isotopes in environmental and biological samples are crucial. This article reviews many aspects of radium chemistry, which includes recent developments in radiochemical separations methods, advancements in analytical techniques followed by a more detailed discussion on the recent trends in radium determination.


Assuntos
Fraturamento Hidráulico , Monitoramento de Radiação , Rádio (Elemento) , Poluentes Radioativos da Água , Radioisótopos/análise , Rádio (Elemento)/análise , Poluentes Radioativos da Água/análise
4.
Sci Total Environ ; 748: 142236, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33039138

RESUMO

The rise of hydraulic fracturing and unconventional oil and gas (UOG) exploration in the United States has increased public concerns for water contamination induced from hydraulic fracturing fluids and associated wastewater spills. Herein, we collected surface and groundwater samples across Garfield County, Colorado, a drilling-dense region, and measured endocrine bioactivities, geochemical tracers of UOG wastewater, UOG-related organic contaminants in surface water, and evaluated UOG drilling production (weighted well scores, nearby well count, reported spills) surrounding sites. Elevated antagonist activities for the estrogen, androgen, progesterone, and glucocorticoid receptors were detected in surface water and associated with nearby shale gas well counts and density. The elevated endocrine activities were observed in surface water associated with medium and high UOG production (weighted UOG well score-based groups). These bioactivities were generally not associated with reported spills nearby, and often did not exhibit geochemical profiles associated with UOG wastewater from this region. Our results suggest the potential for releases of low-saline hydraulic fracturing fluids or chemicals used in other aspects of UOG production, similar to the chemistry of the local water, and dissimilar from defined spills of post-injection wastewater. Notably, water collected from certain medium and high UOG production sites exhibited bioactivities well above the levels known to impact the health of aquatic organisms, suggesting that further research to assess potential endocrine activities of UOG operations is warranted.


Assuntos
Água Subterrânea , Fraturamento Hidráulico , Poluentes Químicos da Água , Colorado , Gás Natural , Campos de Petróleo e Gás , Estados Unidos , Águas Residuárias , Poluentes Químicos da Água/análise , Recursos Hídricos
5.
Water Res ; 185: 116270, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32784035

RESUMO

The flowback water (FW) from shale gas exploitation can be effectively treated by bioelectrochemical technology, but sulfide overproduction remains to be addressed. Herein, sulfate-reducing bacteria (SRB) meditated microbial fuel cells (MFCs) with anodic potential control were used. COD removal gradually increased to 67.4 ± 5.1% in electrode-potential-control (EPC) MFCs and 78.9 ± 2.4% in the MFC with open circuit (OC-MFC). However, in EPC MFCs sulfate removal stabilized at much lower levels (no more than 19.9 ± 1.9%) along with much lower sulfide concentrations, but in OC-MFC it increased and finally stabilized at 59.9 ± 0.1%. Partial sulfur reuse in EPC MFCs was indicated by the current production. Notably, thiosulfate was specially detected under low potentials and effectively oxidized in EPC MFCs, especially under -0.1 V vs. SHE, which probably related to the sulfur reuse. Metagenomics analysis showed that the anode with -0.1 and -0.2 V likely shunted electrons from cytochromes that used for reducing DsrC-S0 trisulfide and thus contributed to producing thiosulfate and decreasing sulfide production. Meanwhile, the anode with -0.1 V specially accumulated sulfur-oxidizing system (Sox) genes regarding thiosulfate and sulfite oxidation to sulfate, which concurred to the effective thiosulfate oxidation and also indicated the possible direct sulfite oxidation to sulfate during the sulfur cycling. But the anode of -0.2 V highly accumulated genes for thiosulfate and sulfite reduction. Both anodes also distinctly accumulated genes regarding thiosulfate oxidation to tetrathionate and sulfide oxidation to sulfur or polysulfide. Further, sulfur-oxidizing bacteria were specially enriched in EPC MFCs and likely contributed to thiosulfate and sulfite oxidation. Thus, we suggested that the higher electrode potential (e.g. -0.1 V) can shape a cryptic sulfur cycling, in which sulfate was first reduced to sulfite, and then reoxidized to sulfate by forming thiosulfate as an important intermediate or by direct sulfite oxidation. The results provide new sights on the bioelectrochemical treatment of wastewater containing complex organics and sulfate.


Assuntos
Fontes de Energia Bioelétrica , Fraturamento Hidráulico , Eletrodos , Oxirredução , Enxofre , Tiossulfatos , Água
6.
PLoS One ; 15(8): e0237325, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810134

RESUMO

Recent research has shown relationships between health outcomes and residence proximity to unconventional oil and natural gas development (UOGD). The challenge of connecting health outcomes to environmental stressors requires ongoing research with new methodological approaches. We investigated UOGD density and well emissions and their association with symptom reporting by residents of southwest Pennsylvania. A retrospective analysis was conducted on 104 unique, de-identified health assessments completed from 2012-2017 by residents living in proximity to UOGD. A novel approach to comparing estimates of exposure was taken. Generalized linear modeling was used to ascertain the relationship between symptom counts and estimated UOGD exposure, while Threshold Indicator Taxa Analysis (TITAN) was used to identify associations between individual symptoms and estimated UOGD exposure. We used three estimates of exposure: cumulative well density (CWD), inverse distance weighting (IDW) of wells, and annual emission concentrations (AEC) from wells within 5 km of respondents' homes. Taking well emissions reported to the Pennsylvania Department of Environmental Protection, an air dispersion and screening model was used to estimate an emissions concentration at residences. When controlling for age, sex, and smoker status, each exposure estimate predicted total number of reported symptoms (CWD, p<0.001; IDW, p<0.001; AEC, p<0.05). Akaike information criterion values revealed that CWD was the better predictor of adverse health symptoms in our sample. Two groups of symptoms (i.e., eyes, ears, nose, throat; neurological and muscular) constituted 50% of reported symptoms across exposures, suggesting these groupings of symptoms may be more likely reported by respondents when UOGD intensity increases. Our results do not confirm that UOGD was the direct cause of the reported symptoms but raise concern about the growing number of wells around residential areas. Our approach presents a novel method of quantifying exposures and relating them to reported health symptoms.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Exposição Ambiental/efeitos adversos , Fraturamento Hidráulico , Gás Natural/efeitos adversos , Campos de Petróleo e Gás , Adulto , Monitoramento Ambiental/estatística & dados numéricos , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Pennsylvania , Estudos Retrospectivos , Níveis Máximos Permitidos
7.
PLoS One ; 15(7): e0236726, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32726370

RESUMO

Hydraulic fracturing is a key method used in completion of shale gas wells as well as in well stimulation. There are a lot of factors affecting the hydraulic fracturing treatment; i.e. formation in-situ stresses, fracturing fluid properties, proppant, pumping rate, reservoir fluid and rock properties…etc. For predictive modeling, these factors are associated with a lot of uncertainties, since most of them are laboratory measured, calculated or subjectively estimated. Moreover, the precise contribution of each factor on the final fracturing result is unknown for each individual case. Therefore, for better treatment performance and in order to find the best range of designing parameters, a hydraulic fracturing predictive model that involves these uncertainties is required specially for newly exploited shale gas reservoir. In this paper a new uncertainty-based approach is described for hydraulic fracturing processes. It is based on assigning probability distribution for some variables and parameters used in the designing process. These probability distributions are used as input data for analytical equations that describe the fracturing processes. Monte Carlo Simulation technique is used to apply uncertainty-based values on the designing analytical formulas. A hypothetical hydraulic fracturing example is used to simulate the effect of different variables and designing parameters on the entire fracturing process. The simulation results are illustrated into probability distribution curves and variance-based sensitivity analysis is performed to assess the contribution and the correlation between different variables and outcomes. Fracture geometry is almost controlled by the injection fluid's viscosity, in case of constant injection rate; while rock properties have insignificant effect on the fracture width compares to fracturing fluid's effect. Therefore more emphases shall be directed to rheological modeling of the fracturing fluid. It is found also that fracture height, which is difficult to be estimated, is the most crucial parameter in the calculation of treatment size or the injected fluid's volume. Proppant porosity, injected fluid viscosity and formation strength are slightly affecting propped fracture width, while proppant final concentration plays the main role of determining the calculated propped fracture width. It is observed from the simulation results that the initial formation permeability will extremely affect the post fracturing skin factor while other formation rock properties have almost no effect on the skin factor. Throughout the implementation of the uncertainty-based modeling approach for hydraulic fracturing process design, it is found that uncertainties in the value of many variables and parameters are slightly affecting the process outcomes. However, injected fluid viscosity, shale formation permeability and proppant final concentration are found to be the most influencing factors in the entire process. Therefore, it is highly recommended to perform in-depth study for these factors prior conducting any designing process of hydraulic fracturing.


Assuntos
Fraturamento Hidráulico , Método de Monte Carlo , Incerteza
8.
J Environ Manage ; 268: 110715, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32510448

RESUMO

Chemical additives used in hydraulic fracturing fluids (HFFs) are made up of various organic compounds that are potential human carcinogens. To estimate the emissions from these organic constituents in on-site liquid storage tanks, studies were performed using the AP-42 model on data collected from 72,023 wells put into production using hydraulic fracturing between 2008 and 2014 in the United States. Results show that a total of 8.11 × 105 kg volatile organic compounds (VOCs) were potentially emitted from liquid storage tanks during fracturing operations, which was relatively low compared to other sources/activities in well fracturing. The median well emission roughly increased from 0.110 to 0.786 kg per well in 2008 and 2014, respectively, and was primarily due to the increase in the volume of chemical additives for fracturing one well. Of NMVOC emissions, 95.1% was contributed by 60 compounds listed on the priority list of hazardous substances defined by the Agency for Toxic Substances & Disease Registry (ATSDR), while 16.7% was caused by 15 carcinogenic compounds. Specially, methanol, formaldehyde, 2-propanol, and ethanol accounted for 55.5%, 16.6%, 11.7%, and 8.31% of NMVOC emissions. Our study highlights methanol, formaldehyde, 2-propanol, and ethanol as the targeted compounds for reducing organic emissions and occupational inhalation exposures related to storage tank operations.


Assuntos
Poluentes Atmosféricos , Fraturamento Hidráulico , Compostos Orgânicos Voláteis , Substâncias Perigosas , Humanos , Veículos Automotores , Estados Unidos , Poços de Água
9.
Chemosphere ; 257: 127178, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32505947

RESUMO

Hydraulic fracturing (HF) technology is increasingly utilized for oil and gas extraction operations. The widespread use of HF has led to concerns of negative impacts on both the environment and human health. Indeed, the potential endocrine disrupting impacts of HF chemicals is one such knowledge gap. Herein, we used structure-based molecular docking to assess the binding affinities of 60 HF chemicals to the human androgen receptor (AR). Five HF chemicals had relatively high predicted AR binding affinity, suggesting the potential for endocrine disruption. We next assessed androgenic and antiandrogenic activities of these chemicals in vitro. Of the five candidate AR ligands, only Genapol®X-100 significantly modified AR transactivation. To better understand the structural effect of Genapol®X-100 on the potency of AR inhibition, we compared the antiandrogenic activity of Genapol®X-100 with that of its structurally similar chemical, Genapol®X-080. Interestingly, both Genapol®X-100 and Genapol®X-080 elicited an antagonistic effect at AR with 20% relative inhibitory concentrations of 0.43 and 0.89 µM, respectively. Furthermore, we investigated the mechanism of AR inhibition of these two chemicals in vitro, and found that both Genapol®X-100 and Genapol®X-080 inhibited AR through a noncompetitive mechanism. The effect of these two chemicals on the expression of AR responsive genes, e.g. PSA, KLK2, and AR, was also investigated. Genapol®X-100 and Genapol®X-080 altered the expression of these genes. Our findings heighten awareness of endocrine disruption by HF chemicals and provide evidence that noncompetitive antiandrogenic Genapol®X-100 could cause adverse endocrine health effects.


Assuntos
Disruptores Endócrinos/toxicidade , Antagonistas de Androgênios/química , Antagonistas de Receptores de Andrógenos/farmacologia , Androgênios , Disruptores Endócrinos/química , Humanos , Fraturamento Hidráulico , Simulação de Acoplamento Molecular , Receptores Androgênicos/metabolismo
10.
J Environ Radioact ; 220-221: 106300, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32560888

RESUMO

Concentrations of naturally occurring radioactive material (NORM) in Marcellus Shale produced water presents a challenge for effective management and treatment, because of the vast fluid volumes generated. With an increased emphasis on beneficial reuse and resource recovery from the produced waters, a rapid, yet reliable, method for quantifying radium in these produced waters is needed. The high total dissolved solids (TDS) concentration introduces difficulties when measuring 226Ra by recommended EPA methods that were specifically developed several decades ago for drinking water. While other techniques for measuring radium in these high-TDS fluids have since been developed, these newer techniques often require extensive and complicated pre-concentration steps; and they thus require extensive analytical chemistry skills, utilize hazardous chemicals like hydrofluoric acid, demand long holding times or measurement times, and require high sample volumes. We present a rapid method for 226Ra measurements in high-TDS produced waters by liquid scintillation counting, which has been corroborated herein by concurrent gamma spectrometry analyses. Samples were prepared for analysis by evaporating the fluid and re-suspending the evaporate with acidified distilled deionized water prior to liquid scintillation counting for 1 h. This protocol yielded radium recoveries ≥93%. Per this protocol, the alpha and beta spectra of 226Ra and its daughters were computationally separated by alpha-beta discrimination and spectrum deconvolution. The minimum detectable activities of 226Ra was 0.33 Bq/L (9.0 pCi/L) when the counting time was 60 min and the sample volume was 4 mL. Nine produced waters of varying TDS and radium concentrations from the Marcellus Shale Formation were analyzed by this method and compared with gamma spectroscopy; and these yielded comparable results with an R2 of 0.92. The reduced sample preparation steps, low cost, and rapid analysis position this as a well-suited protocol for field-appraisal and screening, when compared to comprehensive radiochemical analysis. We offer that for a given produced water region, routine and local liquid scintillation analyses can be compared and calibrated with infrequent gamma spec analyses, so as to yield a near-real time protocol for monitoring 226Ra levels during hydrofracturing operations. We present this as a pragmatic and efficient protocol for monitoring 226Ra when produced water samples host low levels of 228Ra-since the progeny of 228Ra can significantly confound the LSC analyses.


Assuntos
Monitoramento de Radiação , Contagem de Cintilação , Fraturamento Hidráulico , Rádio (Elemento) , Poluentes Radioativos da Água
11.
Environ Sci Pollut Res Int ; 27(21): 26532-26542, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32372354

RESUMO

Large amounts of fracturing flowback and wastewater with complex compositions are produced during hydraulic fracturing. Characterization of hydraulic fracturing flowback and produced water (HF-FPW) is an important initial step in efforts to determine a suitable treatment method for this type of wastewater. In the present study, fracturing flowback and produced water samples were obtained from well CN-F and well CN-E in the prophase and anaphase stages of the Changning shale gas mining area. Chemical characterization of inorganic and organic substances was then conducted. Metal contents were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), and all inorganic anions involved were determined by ion chromatography. The organic pollutant components were analyzed in detail by combining Fourier transform infrared spectrometer (FTIR) and gas chromatography-mass spectrometer (GC-MS). Results showed that samples contained salt (TDS = 30,000-50,000 mg/L), metals (e.g., 650 ± 50 mg/L calcium), and total organic carbon (TOC = 32-178 mg/L). The organic substances detected in all samples could be divided into six categories, alkanes, aromatics, halogenated hydrocarbons, alcohols, esters, and ketones. C6-C21 straight-chain alkanes and C7-C13 naphthenes had the highest amount of organic matter, reaching more than 48%. The organic matter contained fracturing fluid additives, such as surfactants (e.g., ethylene glycol), and nitrotrichloromethane, which is a chlorinated product of some additives. These results provide information on the chemical composition of HF-FPW in Sichuan, China, as well as a basis for subsequent processing.


Assuntos
Fraturamento Hidráulico , Poluentes Químicos da Água/análise , China , Gás Natural , Águas Residuárias , Água
12.
J Chromatogr A ; 1622: 461094, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32362359

RESUMO

This work describes the development of a solid-phase extraction method capable of detecting common fracturing fluid additives in flowback and produced water with mass spectrometry. Dissolved organic carbon (DOC) was used as a bulk measurement to investigate the retentive capacity of seven sorbents and to determine a loading volume. Conductivity was used to determine rinse volume. Based on this, four sorbents (HLB, PPL, Carbon, and C-18) were selected for further investigation of their ability to recover common fluid additives. Enrichment factors were calculated for poly(ethylene) glycols (PEGs), PEG-amines, and their metabolites PEG-carboxylates and PEG-carboxylate-amines, poly(propylene) glycols (PPGs), and linear alkyl ethoxylates (LAEs). The sorbent HLB gave the greatest enrichment for all of these compounds, with an average of 8.0× for PEGs, 11.9× for PEG-amines, 4.9× for PEG-carboxylates, and 21.6× for LAEs, though enrichment was highly dependent on sample composition. The effect was more pronounced for higher molecular weight compounds and enabled detection of some compounds in saltier samples. Then, HLB was used to recover these additives from 1:200 and 1:1000 dilutions in groundwater, illustrating the ability of solid-phase extraction to detect these compounds at low levels (<100 ppb) and highlighting the utility of desalting. This method was used to identify ethoxylated amines in flowback and produced waters from across the country.


Assuntos
Técnicas de Química Analítica , Fraturamento Hidráulico , Extração em Fase Sólida , Águas Residuárias , Poluentes Químicos da Água , Carbono/análise , Técnicas de Química Analítica/métodos , Técnicas de Química Analítica/normas , Água Subterrânea/química , Espectrometria de Massas , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
13.
Environ Sci Technol ; 54(12): 7320-7329, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32401022

RESUMO

Uranium and other radionuclides are prominent in many unconventional oil/gas shales and is a potential contaminant in flowback/produced waters due to the large volumes/types of chemicals injected into the subsurface during stimulation. To understand the stability of U before and after stimulation, a geochemical study of U speciation was carried out on three shales (Marcellus, Green River, and Barnett). Two types of samples for each shale were subjected to sequential chemical extractions: unreacted and shale-reacted with a synthetic hydraulic fracture fluid. A significant proportion of the total U (20-57%) was released from these three shales after reaction with fracture fluid, indicating that U is readily leachable. The total U released exceeds labile water-soluble and exchangeable fractions in unreacted samples, indicating that fluids leach more recalcitrant phases in the shale. Radiographic analysis of unreacted Marcellus shale thin sections shows U associated with detrital quartz and the clay matrix in the shale. Detrital zircon and TiO2 identified by an electron microprobe could account for the hot spots. This study shows that significant proportions of U in three shales are mobile upon stimulation. In addition, the extent of mobilization of U depends on the U species in these rocks.


Assuntos
Fraturamento Hidráulico , Urânio , Minerais , Gás Natural , Campos de Petróleo e Gás , Urânio/análise , Águas Residuárias
14.
Lancet Planet Health ; 4(5): e178-e185, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32442493

RESUMO

BACKGROUND: Hydraulic fracturing often involves the injection of millions of gallons of fracturing fluids into underground shales to extract oil and natural gas, raising health concerns over potential water contamination. Many state and federal governmental agencies rely on the third-party FracFocus online registry for disclosure of chemical ingredients in fracturing fluids, but withholding chemicals as trade secrets is common. In 2016, a new format, known as the systems approach was widely encouraged as a method of reducing withholding by decoupling disclosed chemicals from their functions, protecting against reverse-engineering of fracture fluid formulas by competitors. In this study, we assess the extent to which elevated use of the systems approach in FracFocus version 3.0 translated into greater chemical disclosure. METHODS: We analysed 108 137 disclosure forms submitted to FracFocus between Jan 1, 2011, and Dec 31, 2018, to estimate the effect of expanded use of the systems approach on chemical withholding. We compared the proportion of forms withholding at least one chemical ingredient across time, between approaches, and by state and drilling operator. FINDINGS: Since the 2016 expansion of the systems approach, 15 677 (82%) of systems approach forms have withheld an ingredient. 13 462 (89%) of 15 062 traditional FracFocus version 3.0 forms withheld an ingredient. In the quarter following the transition (July, to September, 2016), 1211 (93%) of 1304 traditional forms withheld an ingredient, compared with only 958 (76%) of 1262 systems approach forms. However, withholding rates increased throughout 2017 and, by 2018, 6949 (87%) of 8016 systems approach forms were withholding ingredients. At the end of our analysis period in the fourth quarter of 2018, systems approach forms had even greater withholding (903 [88%] of 1025 forms) than did traditional forms (855 [85%] of 1004 forms). We did not find that states or operators that submitted more systems approach forms had lower withholding. INTERPRETATION: The systems approach has not reduced FracFocus chemical withholding, which continues to occur in around 87% of well fracture disclosures. FracFocus might not be an appropriate substitute for regulatory action, and measures are urgently needed for environmental and public safety. FUNDING: University of Chicago Argonne National Laboratory Seed Grant.


Assuntos
Revelação/legislação & jurisprudência , Substâncias Perigosas , Fraturamento Hidráulico , Saúde Ambiental , Regulamentação Governamental , Fraturamento Hidráulico/organização & administração , Estados Unidos
15.
Environ Sci Technol ; 54(10): 6289-6298, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32338877

RESUMO

Unconventional extraction techniques including hydraulic fracturing or "fracking" have led to a boom in oil and gas production in the Eagle Ford shale play, Texas, one of the most productive regions in the United States. Nearly 400000 people live within 5 km of an unconventional oil or gas well in this largely rural area. Flaring is associated primarily with unconventional oil wells and is an increasingly common practice in the Eagle Ford to dispose of excess gas through combustion. Flares can operate continuously for months and release hazardous air pollutants such as particulate matter and volatile organic compounds in addition to causing light and noise pollution and noxious odors. We estimated ethnic disparities in exposure to flaring using satellite observations from the Visible Infrared Imaging Spectroradiometer between March 2012-December 2016. Census blocks with majority Hispanic (>60%) populations were exposed to twice as many nightly flare events within 5 km as those with <20% Hispanics. We found that Hispanics were exposed to more flares despite being less likely than non-Hispanic White residents to live near unconventional oil and gas wells. Our findings suggest Hispanics are disproportionately exposed to flares in the Eagle Ford shale, a pattern known as environmental injustice, which could contribute to disparities in air pollution and other nuisance exposures.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar , Fraturamento Hidráulico , Exposição Ambiental , Gás Natural , Campos de Petróleo e Gás , Texas , Estados Unidos
16.
FEMS Microbiol Ecol ; 96(5)2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32286608

RESUMO

The response of microbial communities to releases of hydraulic fracturing flowback and produced water (PW) may influence ecosystem functions. However, knowledge of the effects of PW spills on freshwater microbiota is limited. Here, we conducted two separate experiments: 16S rRNA gene sequencing combined with random forests modelling was used to assess freshwater community changes in simulated PW spills by volume from 0.05% to 50%. In a separate experiment, live/dead cell viability in a freshwater community was tested during exposure to 10% PW by volume. Three distinct patterns of microbial community shifts were identified: (i) indigenous freshwater genera remained dominant in <2.5% PW, (ii) from 2.5% to 5% PW, potential PW organic degraders such as Pseudomonas, Rheinheimera and Brevundimonas became dominant, and (iii) no significant change in the relative abundance of taxa was observed in >5% PW. Microbial taxa including less abundant genera such as Cellvibrio were potential bioindicators for the degree of contamination with PW. Additionally, live cells were quickly damaged by adding 10% PW, but cell counts recovered in the following days. Our study shows that the responses of freshwater microbiota vary by spill size, and these responses show promise as effective fingerprints for PW spills in aquatic environments.


Assuntos
Fraturamento Hidráulico , Microbiota , Biomarcadores Ambientais , RNA Ribossômico 16S/genética , Águas Residuárias/análise , Água
17.
Water Res ; 173: 115467, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32006805

RESUMO

Hydraulic fracturing (HF), or "fracking," is the driving force behind the "shale gas revolution," completely transforming the United States energy industry over the last two decades. HF requires that 4-6 million gallons per well (15,000-23,000 m3/well) of water be pumped underground to stimulate the release of entrapped hydrocarbons from unconventional (i.e., shale or carbonate) formations. Estimated U.S. produced water volumes exceed 150 billion gallons/year across the industry from unconventional wells alone and are projected to grow for at least another two decades. Concerns over the environmental impact from accidental or incidental release of produced water from HF wells ("U-PW"), along with evolving regulatory and economic drivers, has spurred great interest in technological innovation to enhance U-PW recycling and reuse. In this review, we analyze U-PW quantity and composition based on the latest U.S. Geographical Survey data, identify key contamination metrics useful in tracking water quality improvement in the context of HF operations, and suggest "fit-for-purpose treatment" to enhance cost-effective regulatory compliance, water recovery/reuse, and resource valorization. Drawing on industrial practice and technoeconomic constraints, we further assess the challenges associated with U-PW treatment for onshore U.S. operations. Presented are opportunities for targeted end-uses of treated U-PW. We highlight emerging technologies that may enhance cost-effective U-PW management as HF activities grow and evolve in the coming decades.


Assuntos
Fraturamento Hidráulico , Campos de Petróleo e Gás , Objetivos , Gás Natural , Estados Unidos , Águas Residuárias , Poços de Água
18.
Environ Sci Process Impacts ; 22(4): 945-955, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32037427

RESUMO

Hydraulically fractured wells with horizontal drilling (HDHF) accounted for 69% of all oil and gas wells drilled and 670 000 of the 977 000 producing wells in 2016. However, only 238 flowback and produced water samples have been analyzed to date for specific organic chemicals. To aid the development of predictive tools, we constructed a database combining additive disclosure reports and physicochemical conditions at respective well sites with the goal of making synthesized analyses accessible. As proof-of-concept, we used this database to evaluate transformation pathways through two case studies: (1) a filter-based approach for flagging high-likelihood halogenation sites according to experimental criteria (e.g., for a model compound, cinnamaldehyde) and (2) a semi-quantitative, regionally comparative trihalomethane formation model that leverages an empirically derived equation. Study (1) highlighted 173 wells with high cinnamaldehyde halogenation likelihood based on combined criteria related to subsurface conditions and oxidant additive usage. Study (2) found that trihalomethane formation in certain wells within five specific basins may exceed regulatory limits for drinking water based on reaction-favorable subsurface conditions, albeit with wide uncertainty. While experimentation improves our understanding of subsurface reaction pathways, this database has immediate applications for informing environmental monitors and engineers about potential transformation products in residual fluids, guiding well operators' decisions to avoid unwanted transformations. In the future, we envision more robust components incorporating transformation, transport, toxicity, and other physicochemical parameters to predict subsurface interactions and flowback composition.


Assuntos
Fraturamento Hidráulico , Poluentes Químicos da Água , Halogenação , Funções Verossimilhança , Campos de Petróleo e Gás , Águas Residuárias
19.
Environ Res ; 182: 109124, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32069745

RESUMO

BACKGROUND: Hydraulic fracturing together with directional and horizontal well drilling (unconventional oil and gas (UOG) development) has increased substantially over the last decade. UOG development is a complex process presenting many potential environmental health hazards, raising serious public concern. AIM: To conduct a scoping review to assess what is known about the human health outcomes associated with exposure to UOG development. METHODS: We performed a literature search in MEDLINE and SCOPUS for epidemiological studies of exposure to UOG development and verified human health outcomes published through August 15, 2019. For each eligible study we extracted data on the study design, study population, health outcomes, exposure assessment approach, statistical methodology, and potential confounders. We reviewed the articles based on categories of health outcomes. RESULTS: We identified 806 published articles, most of which were published during the last three years. After screening, 40 peer-reviewed articles were selected for full text evaluation and of these, 29 articles met our inclusion criteria. Studies evaluated pregnancy outcomes, cancer incidence, hospitalizations, asthma exacerbations, sexually transmitted diseases, and injuries or mortality from traffic accidents. Our review found that 25 of the 29 studies reported at least one statistically significant association between the UOG exposure metric and an adverse health outcome. The most commonly studied endpoint was adverse birth outcomes, particularly preterm deliveries and low birth weight. Few studies evaluated the mediating pathways that may underpin these associations, highlighting a clear need for research on the potential exposure pathways and mechanisms underlying observed relationships. CONCLUSIONS: This review highlights the heterogeneity among studies with respect to study design, outcome of interest, and exposure assessment methodology. Though replication in other populations is important, current research points to a growing body of evidence of health problems in communities living near UOG sites.


Assuntos
Estudos Epidemiológicos , Fraturamento Hidráulico , Resultado da Gravidez , Exposição Ambiental , Feminino , Humanos , Recém-Nascido , Gás Natural , Campos de Petróleo e Gás , Gravidez
20.
Artigo em Inglês | MEDLINE | ID: mdl-32069816

RESUMO

At the core of the hydraulic fracturing (fracking) debate is the level of perceived risk involved with extractive industries, such as the release of toxic and carcinogenic chemicals, increased population growth, and truck traffic. However, industry supporters of fracking acclaim the benefits of oil and gas drilling, such as energy independence and economic gains. In this study, we examine the perceived impacts of hydraulic fracturing (fracking) on community health and well-being based on interviews with anti-fracking activists in Denton, Texas who were active in the "anti-fracking" community organization, Frack Free Denton (FFD). Emergent from the interviews, we discuss the socio-psychological stressors these community members experienced following the introduction of hydraulic fracturing in the region. Some of the major socio-psychological impacts included perceived physical health risks through anxiety surrounding toxins and carcinogens that may be released through this process. Participants also discussed stress put on community relations, primarily through the form of an "us vs. them" mentality related to the support for, or opposition to, fracking in the community. Moreover, we found anxiety and stress surrounding trust in community members' relationships with governing bodies, such as the federal government, state government, and local governments. This research will allow for a more comprehensive understanding of how fracking can impact the socio-psychological well-being of the community.


Assuntos
Fraturamento Hidráulico , Saúde Pública , Condições Sociais , Estresse Psicológico , Monitoramento Ambiental , Feminino , Humanos , Masculino , Gás Natural , Texas
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