Hydrocarbon Composition Research Articles

Enrichment and movability of lacustrine tight shale oil for the first member of the Upper Cretaceous Qingshankou Formation in the Sanzhao Sag, Songliao Basin, NE China: Insights from saturated hydrocarbon molecules

The Sanzhao Sag is one of the main hydrocarbon generation sags with good shale oil exploration and exploitation potential in the northern Songliao Basin, and the first member of the Upper Cretaceous Qingshankou Formation (K2qn1) is regarded as the most important target layer. In this paper, the complete K2qn1 rock cores from the first shale oil parameter well named the SYY3 well in the study area were taken to investigate tight shale oil enrichment and movability from saturated hydrocarbon molecules combined with bulk organic geochemical characteristics. The results show that the K2qn1 mudstones/shales in the SYY3 well are of high organic matter abundance (1.28–5.62 wt% TOC), good organic matter types (I and II1 kerogens) and medium maturity (0.82%–0.98% Ro), creating excellent material basis of hydrocarbon generation for shale oil enrichment. The molecular compositions of saturated hydrocarbons suggest that the K2qn1 were deposited in reducing brackish lacustrine water with mainly prokaryotes and secondly eukaryotic algae as the biotic input, and are characterized by obvious two-stage distribution with buried depth. The lower unit (>2015.00 m) is generally more enriched in shale oil than the upper unit (<2015.00 m). Relative to the upper unit, the lower unit has lower ratios of pristane/phytane, gammacerane/C30 hopane, C19-20/C21-26 tricyclic terpanes, C24 tetracyclic terpane/C26 tricyclic terpanes, 4-methylstane/C27-29 αααR steranes, higher ratios of regular steranes/17α-hopanes, C27/C29 and C28/C29 αααR sterane, and higher contents of diadrimanes, diahopanes and diasteranes. This indicates that the lower unit can be deposited in a more reducing, lower salinity and more clay-rich sedimentary environment, and contains more eukaryotic algae and less prokaryote biotic input than the upper unit, which can be conducive to the formation and retention of shale oil in the lower unit. The S1 values showing certain positive correlations with regular steranes/17α-hopanes and C27/C29 αααR sterane indicates that the biotic input contribution of eukaryotic algae can be an important positive factor influencing free oil content. The negative correlation between (nC21 + nC22)/(nC28 + nC29) and OSI (S1 × 100/TOC) can be due to diffusion fractionation effect of hydrocarbon molecules in micro-nano reservoir spaces. Low (nC21 + nC22)/(nC28 + nC29) values usually indicate good shale oil movability and reservoir space connectivity under the similar thermal maturity.

Effect of an Inhibitory Composition on the Composition of Paraffin Hydrocarbons in Oil Sediments

Effect of an Inhibitory Composition on the Composition of Paraffin Hydrocarbons in Oil Sediments

Tracing of natural gas migration by light hydrocarbons: A case study of the Dongsheng gas field in the Ordos Basin, NW China

Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane, the indication of geochemical characteristics of light hydrocarbons on the migration features, dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed, and the effect of migration on specific light hydrocarbon indexes is further discussed. The study indicates that, natural gas from the Lower Shihezi Formation (P1x) in the Dongsheng gas field displays higher iso-C5−7 contents than n-C5−7 contents, and the C6−7 light hydrocarbons are composed of paraffins with extremely low aromatic contents (<0.4%), whereas the C7 light hydrocarbons are dominated by methylcyclohexane, suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution. The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging, and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation. Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio, as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values. The dissolution causes the increase of isoheptane values of the light hydrocarbons, whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5−7 contents compared to the iso-C5−7 contents.

Идентификация компонентного состава твердой углеводородной фазы в пласте и оценка ее влияния на поведение подвижного флюида баженовской свиты в процессе разработки залежи

The purpose of the work is to identify the composition of the initial reservoir hydrocarbon (HC) system of the Bazhenov formation, as well as to assess the influence of the presence of a heavy solid hydrocarbon phase (bitumen) in the formation on the production of mobile fluids using PVT modeling methods. The article describes the necessary experiments to determine the component composition of the C81+ fraction and the PVT properties of the formation mobile fluid taken from the well and the bitumen extract from the rock, and also presents their results. In addition, the properties of fractions up to C81+ were calculated depending on the molecular weight for PVT modeling (extension of the Katz-Firuzabadi table). One of the important parts of the article is the assessment of the ratio of bound and free oil in the original reservoir system. Based on geochemical research data, an analysis was performed to assess the component composition of the original system (using the example of the Bazhenov Formation) using rock pyrolysis and studying formation fluid and bitumen. Using the results of studies of reservoir fluid samples, a PVT model was built and tuned. This PVT model was used to assess the properties of the initial reservoir hydrocarbon system and was adjusted to the fraction of the solid phase in the reservoir at the initial reservoir conditions. After this, based on the PVT model, an assessment was made of the influence of the presence of a solid phase in the composition of the reservoir system on the behavior of a mobile hydrocarbon fluid during reservoir development for depletion, as well as on the use of enhanced oil recovery methods (injection of associated petroleum gas and thermal methods of influencing the reservoir).

Prediction of sulfur compounds and total sulfur contents in catalytic cracking products of hydrotreated and non-hydrotreated feeds

Relevance. The lack of a reliable mathematical model suitable for predicting the yield and quality of products in catalytic cracking units, with an assessment of the environmental indicators of fuel fractions when changing the hydrocarbon composition and distribution of sulfur compounds in the process feedstock, as well as the possibility of involving highly sulfur-containing oil streams in processing on existing catalytic cracking units. Aim. To develop and apply a mathematical model of the catalytic cracking to predict the content of sulfur compounds and total sulfur in the products during the processing of hydrotreated and non-hydrotreated petroleum feedstocks. Methods. A complex of experimental methods, including liquid and gas chromatography to determine the composition of the feedstock and the distribution of sulfur compounds in the feedstock and catalytic cracking products, methods of quantum chemical modeling of reactions involving sulfur compounds, as well as numerical methods for processing and solving systems of differential equations. Quantum chemical modeling methods were used to study the thermodynamic parameters of catalytic cracking reactions involving sulfur-containing compounds. Results. The authors have developed and implemented in software a mathematical model of catalytic cracking involving hydrocarbons C1–C40+ and sulfur compounds (thiophenes C0–C4, alkylbenzothiophenes C0–C6, C0–C3 dibenzothiophenes, and C4–dibenzothiophene-benzonaphthothiophenes). The model aims to predict the yield and composition of process products, as well as the environmental indicators of motor fuels. Thermodynamic and kinetic parameters of catalytic cracking reactions were determined using quantum chemical modeling methods and solving the inverse kinetic problem.

Distribution Characteristics and Pollution Sources Analysis of Polycyclic Aromatic Hydrocarbons and Phthalate Esters in the Seawater of Land-Based Outlets around Zhanjiang Bay in Spring

This study analyzed the distribution characteristics and sources of pollutants in the coastal estuaries of Zhanjiang Bay (ZJB) to provide theoretical and data support for the scientific prevention and control of bay pollution. Monitoring data from eight rivers and flood drains flowing into ZJB in March 2021 were used to analyze the composition and spatial distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) in the water bodies of the bay. The dominant components in the eight rivers and flood drains were 3–4-ring PAHs, with Bis (2-ethylhexyl) phthalate (DEHP), Diisobutyl phthalate (DIBP), and Dibutyl-O-phthalate (DBP) being the main PAE compounds. Higher pollutant levels were observed in residential areas, aquaculture zones, and industrial areas. Eigen-ratio analysis and principal component analysis were used to identify pollution sources, including atmospheric inputs (coal, petroleum products, biomass combustion products), offshore petroleum pollution, and plastic pollution sources. The assessment showed that atmospheric inputs contributed to 89.75% of the total PAHs in the bay, with coal and biomass combustion accounting for 62.12% and petroleum fuel combustion accounting for 27.63%. The content of ΣPAEs ranged from 588.43 to 1427.26 ng·L−1, with a mean value of 906.59 ng·L−1, which is at a low to medium level compared to other regions of China and abroad, indicating a medium-low level of pollution risk. The results of this study have important implications for guiding urban development, adjusting energy consumption structures, and planning pollution prevention and control measures in ZJB.

Solid bitumen as an indicator of petroleum migration, thermal maturity, and contact metamorphism: A case study in the Barrandian Basin (Silurian - Devonian), Czech Republic

Silurian and Devonian marine shales and limestones of the Barrandian Basin host abundant black solid, non-fluorescing bitumens that fill tectonic fractures and veins, and occlude fossil moulds and diagenetic concretions. Solid bitumen, interpreted as thermally degraded petroleum, entered the rocks during several successive episodes of fracture-bound petroleum migration that occurred during deeper burial of the strata. Regional distribution of bitumen reflectance values that range between ∼0.9–2.3% Rr, correlate with variations of its FT-IR and Raman spectroscopic characteristics and aromatic hydrocarbon composition, and collectively evidence the maturity trend increasing across the basin from the southwest to the northeast. The reflectance of chitinozoans and graptolites (∼0.8–1.9% Rr) in the country rocks and homogenization temperatures of hydrocarbon fluid inclusions document palaeotemperatures ranging between ∼90–150 °C, characteristic of the oil window zone grading into the gas/condensate zone. Although in a basin-wide perspective the averaged values of solid bitumen and zooclast optical reflectance converge and indicate the same northeastern-increasing regional diagenetic trend, solid bitumen reflectance values vary considerably at individual localities and even within some bitumen samples. The wide scatter of optical reflectance values and the heterogeneity of optical properties, which were attributed to the presence of multiple source rocks in the basin, the variable lithology of bitumen host rocks, or other variables, hamper the use of solid bitumen as a simple alternative to zooclast/vitrinite reflectance palaeothermometers in a given basin. On the other hand, the highly anisotropic domain and the mesophase “coking” textures of the solid bitumen that were recognized in the NE part of the basin provide unique evidence on an anomalous, hitherto unrecognized, geologically short-lasting thermal event that affected the Palaeozoic rocks. A line of indirect evidence suggests that the coking of the bitumen was caused by a cryptic intrusion, possibly a concealed branch of the Central Bohemian Pluton, which intruded into the strata during the Variscan orogeny. More rarely occurring semi-solid, vividly yellow fluorescing waxy bitumen, that postdates solid bitumen in some fractures and voids, does not reveal a regional thermal maturation trend. It precipitated from relict waxy oils that migrated through the strata during a post-Neogene uplift of the Barrandian region.

Rhinoceros beetle (Trypoxylus dichotomus) cuticular hydrocarbons contain information about body size and sex.

Japanese rhinoceros beetle (Trypoxylus dichotomus) males have exaggerated horns that are used to compete for territories. Larger males with larger horns tend to win these competitions, giving them access to females. Agonistic interactions include what appears to be assessment and often end without escalating to physical combat. However, it is unknown what information competitors use to assess each other. In many insect species chemical signals can carry a range of information, including social position, nutritional state, morphology, and sex. Specifically, cuticular hydrocarbons (CHCs), which are waxes excreted on the surface of insect exoskeletons, can communicate a variety of information. Here, we asked whether CHCs in rhinoceros beetles carry information about sex, body size, and condition that could be used by males during assessment behavior. Multivariate analysis of hydrocarbon composition revealed patterns associated with both sex and body size. We suggest that Rhinoceros beetles could be communicating information through CHCs that would explain behavioral decisions.

Cuticular Hydrocarbon Profiles of Himalayan Bumble Bees (Hymenoptera: Bombus Latreille) are Species-Specific and Show Elevational Variation.

Bumble bees are important pollinators in natural environments and agricultural farmlands, and they are in particular adapted to harsh environments like high mountain habitats. In these environments, animals are exposed to low temperature and face the risk of desiccation. The Eastern Himalayas are one of the recognized biodiversity hotspots worldwide. The area covers subtropical rainforest with warm temperature and high precipitation as well as high mountain ranges with peaks reaching up to 7,000m, shaping a diverse floral and faunal community at the different elevational zones. To identify possible adaptation strategies, we investigated the cuticular hydrocarbon profiles of four bumble bee species occurring at different elevational ranges in Arunachal Pradesh, the northeastern most state in India. At 17 locations along an elevational gradient, we collected workers of two species from lower elevations (B. albopleuralis and B. breviceps; ~ 100m - 3,000m asl) and two species from higher elevations (B. prshewalskyi and B. mirus; ~ 2,800m - 4,500m asl). The CHC profiles of all four species showed a significant degree of variation in the composition of hydrocarbons, indicating species specificity. We also found clear correlation with elevation. The weighted mean chain length of the hydrocarbons significantly differed between the low and high elevation species, and the proportion of saturated hydrocarbons in CHC profiles significantly increased with the elevational range of the bumble bee species. Our results indicate that bumble bees living at high elevations reduce the risk of water loss by adapting their CHC composition on their cuticle, a phenomenon that has also been found in other insects like ants and fruit flies.

Rapid determination of chemical compositions of raw materials and intermediate products of lube base oil by near infrared spectroscopy combined with library spectral fitting method

Rapid analysis of the detailed hydrocarbon composition of vacuum gas oil, hydrocracking bottom oil, and hydrogenated lube base oil is a critical technology in the production of hydrogenated lube base oil. In this study, based on a quantity of representative samples, a novel approach for estimating the hydrocarbon composition for vacuum gas oil, hydrocracking bottom oil and hydrogenated lube base oil was developed by near infrared (NIR) spectra combined with new chemometric method called library spectra fitting. The proposed method can reduce the maintenance requirements of traditional multivariate calibration such as partial least squares (PLS) apparently. The results of NIR analysis are basically consistent with ASTM standard method, which can fulfill the needs of rapid analysis in industrial field. Currently, the technology and corresponding software tools have been applied in a petroleum refinery.

Characterization of chemical composition of high viscosity heavy oils: Macroscopic properties, and semi-quantitative analysis of molecular composition using high-resolution mass spectrometry

Heavy oil is an important resource in current petroleum exploitation, and the chemical composition information of heavy oil is crucial for revealing its viscosity-inducing mechanism and solving practical exploitation issues. In this study, the techniques of high-temperature gas chromatography and high-resolution mass spectrometry equipped with an electrospray ionization source were applied to reveal the chemical composition of typical heavy oils from western, central, and eastern China. The results indicate that these heavy oils display significant variations in their bulk properties, with initial boiling points all above 200 °C. Utilizing pre-treatment and ESI high-resolution mass spectrometry, an analysis of the molecular composition of saturated hydrocarbons, aromatic hydrocarbons, acidic oxygen compounds, sulfur compounds, basic nitrogen compounds, and neutral nitrogen compounds within the heavy oil was conducted. Ultimately, a semi-quantitative analysis of the molecular composition of the heavy oil was achieved by integrating the elemental content. The semi-quantitative analysis results of Shengli-J8 heavy oil and a conventional Shengli crude oil show that Shengli-J8 heavy oil lacks alkanes and low molecular weight aromatic hydrocarbons, which contributes to its high viscosity. Additionally, characteristic molecular sets for different heavy oils were identified based on the semi-quantitative analysis of molecular composition. The semi-quantitative analysis of molecular composition in heavy oils may provide valuable reference data for establishing theoretical models on the viscosity-inducing mechanism in heavy oils and designing viscosity-reducing agents for heavy oil exploitation.

Late Pleistocene emergence of an anthropogenic fire regime in Australia’s tropical savannahs

At the time of European arrival on the Australian continent, sophisticated Indigenous societies practiced land management across Australia’s extensive tropical savannahs. Fire was one of the main tools people used to manipulate fuel loads and connectivity to reduce uncontrolled wildfire, maintain vegetation structure and enhance biodiversity. When this alteration of a ‘natural’ fire regime to a human-dominated fire regime occurred is not known. Here we assessed fire incidence and intensity over the past 150,000 years through a continuous lacustrine record by comparing the accumulation rates of micro-charcoal and stable polycyclic aromatic hydrocarbon that form during the combustion of vegetation. We also compared grass (mainly C4) pollen as a percentage of total dryland pollen with the carbon isotope composition of the stable polycyclic aromatic hydrocarbon. We established with high statistical certainty that a change in fire regime occurred at least 11,000 years ago from less-frequent, more-intense fires to more-frequent, less-intense fires. This change marked the overprinting of a largely natural fire regime by one at least modulated by Indigenous management. Our findings demonstrate that human fire use has modified fire regimes throughout the Holocene and also show how people have managed the potential for the type of high-intensity fires that are likely to increase in the future.

Pressure-volume-temperature analysis of Caspian oil to improve the analytical delumping procedure

Compositional modeling of the reservoir isn’t complete without calculations of phase equilibrium and is a complex process involving many calculations. In nature, hydrocarbons don’t occur as separate components, they’re mainly mixtures. When modeling the reservoir composition for phase equilibrium calculations, in order to reduce computational costs, in practice, hydrocarbon mixtures are grouped into pseudo-components. The number of grouped pseudo-components varies from 4 to 10. This grouping process is called lumping. However, when crude oil comes to the surface, it’s important to know its detailed composition, since mixtures grouped into pseudo-components don’t allow you to know this. In this regard, modeling of the detailed composition of hydrocarbons is the main tool for understanding the detailed phase separation and design of surface facilities. In practice, this process is called delumping. In the case of this process, the detailed composition of the fluid is presented and the amount reaches up to 36 components, sometimes more. The delumping process, due to the precise separation of heavy plus fractions into carbons with single ordinal numbers (C7, C8, etc.), makes it possible to clearly recognize non-zero BIP’s in the equation of state. The new analytical approach has not previously been applied to the oils of the Caspian region, so this approach has an important role for the oil industry in the Caspian region. Analytical delumping in this paper was done to improve the PVT modeling. This paper presents the results of PVT research of Caspian oil and presents a comparison of analytical and numerical methods of delumping. As a result of the study, it was found that the analytical approach is in excellent agreement with experimental data and data from software such as PVTsim

Catalytic pyrolysis of brewer's spent grain in spouted bed reactor using calcium oxide for upgrading oil

This study investigates the potential of brewer's spent grain as a fuel source through fast pyrolysis in a spouted bed reactor, aiming to contribute to sustainable fuel alternatives and the mitigation of the environmental consequences of fossil fuel consumption. Both non-catalytic and catalytic tests evaluated the effects of temperature, biomass feed rate, and catalyst concentration on yields and hydrocarbon composition. The intermediate temperature (550 °C) and biomass feed rate (960 g/h) were optimal for non-catalytic tests, favoring oil production. Additionally, the oil yield was enhanced with the use of CaO as a catalyst during the pyrolysis process. An optimization study identified conditions maximizing both liquid yield and hydrocarbon content. While catalytic tests showed a modest increase in oil yield compared to non-catalytic tests, the addition of CaO significantly improved oil quality by increasing hydrocarbon concentration and facilitating deoxygenation. Under optimal conditions, non-catalytic pyrolysis achieved a 41% liquid yield with 15% hydrocarbon content. For catalytic pyrolysis, optimal conditions yielded 43% oil with a hydrocarbon content of 33% and low water content. Moreover, the resulting oil exhibited a higher heating value (HHV) of 25.7 MJ/kg compared to the spent grain's 19.8 MJ/kg. Utilizing the CaO catalyst further increased the HHV value to 28.2 MJ/kg, highlighting its efficiency in enhancing liquid product quality. The solid products resembled mineral coals with higher energy density compared to the feedstock. This study highlights the potential of brewer's spent grain for fuel production in a spouted bed reactor and the CaO catalyst's effectiveness in improving liquid product quality.

Geoffrey Eglinton. 1 November 1927—11 March 2016

Where have all life's molecules gone? Recycled to carbon dioxide every one! Ah! But look—a hardy few remain As biomarkers imprisoned in the fossil domain (G. Eglinton &amp; R. Pancost, Immortal molecules ( 47 )) Geoffrey Eglinton trained as an organic chemist at the University of Manchester working on acetylene synthesis, and the Eglinton reaction signifies his discovery of an effective method for their oxidative coupling. At the University of Glasgow, he recognized the potential of analytical advances to open new frontiers for characterization of molecular constituents of complex mixtures and continued to adopt and adapt instrumental techniques throughout his career. Eglinton's exploration of plant leaf waxes, and their taxonomic profiles, prompted forays in organic geochemistry, seeking molecular evidence for ancient life. Thus, his focus shifted to studying ‘chemical fossils’ preserved in the rock record and pioneering identification and interpretation of their compositions. At the University of Bristol, he established the Organic Geochemistry Unit and steered its rise to international prominence as a leading centre for research, a legacy that continues today. He served in planning the Apollo sampling programme and led research that explicated the carbon chemistry of the Moon. Major advances in using molecules as witnesses of the origins and fate of sedimentary organic matter bear the hallmarks of his insightful contributions and commitment to interdisciplinary, collaborative ventures. They include deciphering how environmental controls and thermal transformations govern the composition of petroleum hydrocarbons, and validating the ability for molecules to afford invaluable evidence of past climates. Eglinton's research accomplishments were recognized by many prestigious awards, including a Royal Gold Medal of the Royal Society, the V. M. Goldschmidt Medal of the Geochemical Society, the Wollaston Medal of the Geological Society, and the Dan David Prize.

Cuticular chemical compounds of puparial cases of three forensically important blow flies from Egypt: potential for accurate identification and forensic investigations

AbstractThe distinct and species-specific chemical compounds found on the insect cuticle have demonstrated effectiveness in various applications, including species identification. Accurate identification of fly species becomes challenging when only damaged empty puparial cases are available, making it difficult to use traditional morphological and molecular identification methods. This study aimed to analyze the chemical compositions of puparial exuviae from three forensically and medically important fly species; Lucilia sericata, Chrysomya albiceps, and Chrysomya marginalis. Gas chromatography/mass spectrometry (GC–MS) was employed to assess the chemical profiles of these exuviae and evaluate their accuracy in identifying Dipteran insects. The study revealed the presence of twelve classes of chemical compounds across the three species, with retention times ranging from 18.78 to 35.03. A total of forty-two compounds with chain lengths ranging from C12 to C45 were identified. The profiles of Ch. albiceps and L. sericata displayed similarities, with alcohol being the most abundant compound (28.6%) in L. sericata. However, alkanes, including n-alkanes, branched alkanes, and cycloalkanes, constituted the main components of the cuticles in the three species, with Ch. marginalis displaying the highest percentage. These findings represent an initial step towards utilizing hydrocarbon composition as a practical tool for distinguishing between forensic species in Egypt.

Well Logs Analysis and Reservoir Evaluation of Hartha Formation in the East Baghdad oil field central Iraq

This study objective of ascertaining various petrophysical properties, which encompass volume shale, porosity, and water saturation. Well logging assumes a pivotal role in the comprehensive evaluation of reservoirs by providing measurements that can be effectively correlated with the volume fraction and composition of hydrocarbons within porous geological formations.In the course of this research, the quantification of shale volume was achieved through the utilization of gamma-ray logs, while the determination of effective porosity was facilitated by employing porosity logs, including the density log, neutron log, and sonic or acoustic log. The Hartha Formation has been stratified into distinct reservoir units based on their petrophysical characteristics. The interpretation of the findings involved the direct examination of well log readings, complemented by the application of well-established relationships and profiles to discern the critical lithological and petrophysical attributes inherent to the Hartha Formation. The selected wells from the East Baghdad oilfield, namely EB-93, EB-97, EB-51, and EB-42.

Radio Jet Feedback on the Inner Disk of Virgo Spiral Galaxy Messier 58

Spitzer spectral maps reveal a disk of highly luminous, warm (>150 K) H2 in the center of the massive spiral galaxy Messier 58, which hosts a radio-loud active galactic nucleus (AGN). The inner 2.6 kpc of the galaxy appears to be overrun by shocks from the radio jet cocoon. Gemini NIRI imaging of the H2 1–0 S(1) emission line, Atacama Large Millimeter/submillimeter Array CO 2–1, and Hubble Space Telescope multiband imagery indicate that much of the molecular gas is shocked in situ, corresponding to lanes of dusty molecular gas that spiral toward the galactic nucleus. The CO 2–1 and ionized gas kinematics are highly disturbed, with velocity dispersion up to 300 km s−1. Dissipation of the associated kinetic energy and turbulence, likely injected into the interstellar medium by radio-jet-driven outflows, may power the observed molecular and ionized gas emission from the inner disk. The polycyclic aromatic hydrocarbon (PAH) fraction and composition in the inner disk appear to be normal, in spite of the jet and AGN activity. The PAH ratios are consistent with excitation by the interstellar radiation field from old stars in the bulge, with no contribution from star formation. The phenomenon of jet-shocked H2 may substantially reduce star formation and help to regulate the stellar mass of the inner disk and supermassive black hole in this otherwise normal spiral galaxy. Similarly strong H2 emission is found at the centers of several nearby spiral and lenticular galaxies with massive bulges and radio-loud AGNs.

Illegal dumping of oil and gas wastewater alters arid soil microbial communities.

The Permian Basin, underlying southeast New Mexico and west Texas, is one of the most productive oil and gas (OG) provinces in the United States. Oil and gas production yields large volumes of wastewater with complex chemistries, and the environmental health risks posed by these OG wastewaters on sensitive desert ecosystems are poorly understood. Starting in November 2017, 39 illegal dumps, as defined by federal and state regulations, of OG wastewater were identified in southeastern New Mexico, releasing ~600,000 L of fluid onto dryland soils. To evaluate the impacts of these releases, we analyzed changes in soil geochemistry and microbial community composition by comparing soils from within OG wastewater dump-affected samples to unaffected zones. We observed significant changes in soil geochemistry for all dump-affected compared with control samples, reflecting the residual salts and hydrocarbons from the OG-wastewater release (e.g., enriched in sodium, chloride, and bromide). Microbial community structure significantly (P < 0.01) differed between dump and control zones, with soils from dump areas having significantly (P < 0.01) lower alpha diversity and differences in phylogenetic composition. Dump-affected soil samples showed an increase in halophilic and halotolerant taxa, including members of the Marinobacteraceae, Halomonadaceae, and Halobacteroidaceae, suggesting that the high salinity of the dumped OG wastewater was exerting a strong selective pressure on microbial community structure. Taxa with high similarity to known hydrocarbon-degrading organisms were also detected in the dump-affected soil samples. Overall, this study demonstrates the potential for OG wastewater exposure to change the geochemistry and microbial community dynamics of arid soils.IMPORTANCEThe long-term environmental health impacts resulting from releases of oil and gas (OG) wastewater, typically brines with varying compositions of ions, hydrocarbons, and other constituents, are understudied. This is especially true for sensitive desert ecosystems, where soil microbes are key primary producers and drivers of nutrient cycling. We found that releases of OG wastewater can lead to shifts in microbial community composition and function toward salt- and hydrocarbon-tolerant taxa that are not typically found in desert soils, thus altering the impacted dryland soil ecosystem. Loss of key microbial taxa, such as those that catalyze organic carbon cycling, increase arid soil fertility, promote plant health, and affect soil moisture retention, could result in cascading effects across the sensitive desert ecosystem. By characterizing environmental changes due to releases of OG wastewater to soils overlying the Permian Basin, we gain further insights into how OG wastewater may alter dryland soil microbial functions and ecosystems.

Spatiotemporal variations in soil pollution by polycyclic aromatic hydrocarbons over a 20-year economic boom in different districts of a heavy industrial city in North China

Urbanization-related human activities, such as population aggregation, rapid industrial expansion, and intensified traffic, are key factors that impact local polycyclic aromatic hydrocarbon emissions and their associated health risks. Consequently, regions with varying degrees of urbanization within a megacity may exhibit diverse spatiotemporal patterns in the presence and distribution of soil polycyclic aromatic hydrocarbons, resulting in different levels of ecological risks for local inhabitants following the same period of development. In this study, we measured the concentrations of 16 polycyclic aromatic hydrocarbons in soil samples collected from industrial district and rural district in Tianjin (China) in 2018, and compared with polycyclic aromatic hydrocarbon data in 2001 from a previous study to characterize these regional variations in occurrence, source, and human risk of polycyclic aromatic hydrocarbons induced by urbanization with time and space. The results indicate the 20-year rapid urbanization and industrialization has differentially affected the composition, distribution and sources of polycyclic aromatic hydrocarbons in soils from different economic functional zones in Tianjin. Additionally, its impact on health risks in rural district appeared to be more significant than that in industrial district.