Oil Hydrocarbons Research Articles

Determination of Hydrocarbon Production Zones using Well Logging Data in the "North_Rawa" Well of the South Sumatra Basin

Petrophysical analysis with well logging is carried out to determine the value of petrophysical parameters of rocks in the formation. Then to find out information about the subsurface structure as well as the depth zone of layers containing hydrocarbons and the types of hydrocarbons from the production field. In this research, an evaluation of reservoir formation was carried out in the North_Rawa field of the South Sumatra Basin, based on petrophysical log analysis from data from three wells in the North_Rawa field. Reservoir identification results from physical rock parameters such as porosity, shale content, water saturation and permeability obtained from formation evaluation calculations. Porosity is calculated to determine the pores, shale content is calculated to determine the volume of shale in the reservoir, water saturation is calculated to determine the water content in the formation, and permeability is calculated to determine the rock's ability to pass fluid. The results of petrophysical calculations were obtained in the hydrocarbon prospect zone in the North- rawa 1 well at a depth of 3387.5 – 3938 feet, the North- rawa 3 well at a depth of 2667.5 – 3735.5 feet, the North- rawa 4 well at a depth of 2759.5 – 3775 feet. The average porosity values for each well are 8%, 15.4%, 16%. The average shale content value for each well is 61%, 48%, 53%. Average water saturation values are 61%, 54%, 68%. Average permeability values 46.7 mD , 98.9 mD , 3.38 MD. The hydrocarbon prospect in the research well contains natural gas and oil hydrocarbons with sandstone and shale formation lithology.

Progress of Crude Oil Gasification Technology Assisted by Microorganisms in Reservoirs.

Crude oil gasification bacteria, including fermenting bacteria, hydrocarbon-oxidizing bacteria, reducing bacteria, and methanogenic bacteria, participate in multi-step reactions involving initial activation, intermediate metabolism, and the methanogenesis of crude oil hydrocarbons. These bacteria degrade crude oil into smaller molecules such as hydrogen, carbon dioxide, acetic acid, and formic acid. Ultimately, they convert it into methane, which can be utilized or stored as a strategic resource. However, the current challenges in crude oil gasification include long production cycles and low efficiency. This paper provides a summary of the microbial flora involved in crude oil gasification, the gasification metabolism pathways within reservoirs, and other relevant information. It specifically focuses on analyzing the factors that affect the efficiency of crude oil gasification metabolism and proposes suggestions for improving this efficiency. These studies deepen our understanding of the potential of reservoir ecosystems and provide valuable insights for future reservoir development and management.

Concentration unit mistakes in health risk assessment of polycyclic aromatic hydrocarbons in soil, sediment, and indoor/road dust

Concentration unit mistakes in health risk assessment of polycyclic aromatic hydrocarbons in soil, sediment, and indoor/road dust

The Stabilizing Effect of Chitosan‐Modified Biochar (β‐CD/C‐BC) on Agricultural Soil Contaminated by the Cd‐Pyr Complex

AbstractThe composite pollution of heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in agricultural soil is increasingly severe. HMs can undergo surface adsorption, complexation, or chemical reactions to transform from bioavailable species to residual species, achieving chemical morphological stability. However, these processes have no effect on PAHs. Biochar (BC), due to its inherent characteristics, can significantly enhance the stability of PAHs and is recommended as a potential co‐stabilizing material for both heavy metals and PAHs. In this study, rice husk biochar modified with β‐cyclodextrin and chitosan (β‐CD/C‐BC) was utilized to stabilize agricultural soil contaminated by Cd and Pyrene (Pyr). One‐way tests were conducted on the dosage and curing time of biochar after a complete cycle of treatment. The results demonstrated that the optimal effect was achieved when the dosage of β‐CD/C‐BC was 7.5 % or the curing time was 21 days. The removal efficiencies for Cd and Pyr were found to be 84.62 %, 64.22 % or 85.90 %, 65.78 %, respectively. Additionally, BCR testing revealed that β‐CD/C‐BC could convert HMs in soil into a residual state (from 32 % to 82 %) with the highest stabilization rate, thereby reducing their migration ability and ecological risk.

Chemical Activity of Nascent Surfaces for Tribochemical Reactions of Lubricant Components.

Boundary lubrication characteristics are strongly dependent on tribochemical reactions at the contact interface. There are multiple factors that contribute to the activity of tribochemical reactions and the complexity of this phenomenon. Here, we focused on nascent surfaces created by friction and aimed to clarify their chemical properties. To achieve this, we first developed a method based on a mass spectrometer that can sensitively detect molecular adsorption and reactions on a nascent surface. We used various organic compounds as adsorbates and friction materials such as steel, aluminum, gold, and ceramics and examined adsorption of the organic compounds on the nascent surfaces. The adsorption properties of the additives differed between steel metal oxide and nascent steel surfaces. For example, polar organic phosphates, which are extreme-pressure additives, were more easily adsorbed on oxide surfaces, whereas nonpolar organic sulfur compounds were more easily adsorbed on nascent steel surfaces. Alcohols and ethers also adsorbed on nascent aluminum surfaces, whereas olefins and benzene did not. Nascent gold surfaces showed high catalytic activity. Saturated hydrocarbons and fluorinated compounds, which are chemically inert, were also adsorbed on nascent ceramic surfaces, showing high activity. Hydrocarbon oils decomposed through the influence of frictional heat on a nascent steel surface to generate hydrogen and methane. We applied reactive molecular dynamics to simulate the adsorption phenomenon on iron surfaces. As a result, the adsorption energy obtained by simulation and the experimentally determined adsorption activity correlated well. Thus, adsorption and reaction behaviors on nascent surfaces inferred by our method were theoretically supported. On the basis of the chemical properties of the nascent surfaces obtained here, it is possible to explain boundary lubrication phenomena.

Hexose/pentose ratio in rhizosphere exudates-mediated soil eutrophic/oligotrophic bacteria regulates the growth pattern of host plant in young apple-aromatic plant intercropping systems.

The positive effect of intercropping on host plant growth through plant-soil feedback has been established. However, the mechanisms through which intercropping induces interspecific competition remain unclear. In this study, we selected young apple trees for intercropping with two companion plants: medium growth-potential Mentha haplocalyx Briq. (TM) and high growth-potential Ageratum conyzoides L. (TA) and conducted mixed intercropping treatment with both types (TMA) and a control treatment of monocropping apples (CT). Our findings revealed that TM increased the under-ground biomass of apple trees and TA and TMA decreased the above-ground biomass of apple trees, with the lowest above-ground biomass of apple trees in TA. The above- and under-ground biomass of intercrops in TA and TMA were higher than those in TM, with the highest in TA, suggesting that the interspecific competition was the most pronounced in TA. TA had a detrimental effect on the photosynthesis ability and antioxidant capacity of apple leaves, resulting in a decrease in above-ground apple biomass. Furthermore, TA led to a reduction in organic acids, alcohols, carbohydrates, and hydrocarbons in the apple rhizosphere soil (FRS) compared to those in both soil bulk (BS) and aromatic plant rhizosphere soil (ARS). Notably, TA caused an increase in pentose content and a decrease in the hexose/pentose (C6/C5) ratio in FRS, while ARS exhibited higher hexose content and a higher C6/C5 ratio. The changes in exudates induced by TA favored an increase in taxon members of Actinobacteria while reducing Proteobacteria in FRS compared to that in ARS. This led to a higher eutrophic/oligotrophic bacteria ratio relative to TM. This novel perspective sheds light on how interspecific competition, mediated by root exudates and microbial community feedback, influences plant growth and development.

A screening model for predicting the potential of soil colloids-enhanced leaching of hydrophobic organic contaminants to groundwater at contaminated sites

Modeling the fate and transport of organic pollutants at contaminated sites is critical for risk assessment and management practices, such as establishing realistic cleanup standards or remediation endpoints. Against the conventional wisdom that highly hydrophobic persistent organic pollutants (POPs) (e.g., polybrominated diphenyl ethers and polycyclic aromatic hydrocarbons) in surface soils are essentially immobile, mounting evidence has demonstrated the potential of these contaminants leaching into the groundwater, due to enhanced transport by soil colloids. Here, we develop a Colloids-Enhanced Transport (CET) model, which can be used as a simple screening tool to predict the leaching potential of POPs into groundwater, as mediated by soil colloids. The CET model incorporates several processes, including the release of POPs-bearing colloids into the porewater, the vertical transport of colloids and associated POPs in the vadose zone, the mixing of POPs-containing soil leachate with groundwater, and the migration of POPs-bearing colloids in saturated zone. Thus, using parameters that can be easily obtained (e.g., annual rainfall, soil type, and common hydrogeological properties of the subsurface porous media), the CET model can estimate the concentrations of POPs in the saturated zone from the observed POPs concentrations in surface or shallow subsurface zones. The CET model can also be used to derive soil quality standards or cleanup endpoints by back-calculating soil concentrations based on groundwater protection limits.

Bioaugmentation and vermicompost facilitated the hydrocarbon bioremediation: scaling up from lab to field for petroleum-contaminated soils.

The biodegradation of total petroleum hydrocarbon (TPH) in soil is very challenging due to the complex recalcitrant nature of hydrocarbon, hydrophobicity, indigenous microbial adaptation and competition, and harsh environmental conditions. This work further confirmed that limited natural attenuation of petroleum hydrocarbons (TPHs) (15% removal) necessitates efficient bioremediation strategies. Hence, a scaling-up experiment for testing and optimizing the use of biopiles for bioremediation of TPH polluted soils was conducted with three 500-kg pilots of polluted soil, and respective treatments were implemented: including control soil (CT), bioaugmentation and vermicompost treatment (BAVC), and a combined application of BAVC along with bioelectrochemical snorkels (BESBAVC), all maintained at 40% field capacity. This study identified that at pilot scale level, a successful application of BAVC treatment can achieve 90.3% TPH removal after 90 days. BAVC's effectiveness stemmed from synergistic mechanisms. Introduced microbial consortia were capable of TPH degradation, while vermicompost provided essential nutrients, enhanced aeration, and, potentially, acted as a biosorbent. Hence, it can be concluded that the combined application of BAVC significantly enhances TPH removal compared to natural attenuation. While the combined application of a bioelectrochemical snorkel (BES) with BAVC also showed a significant TPH removal, it did not differ statistically from the individual application of BAVC, under applied conditions. Further research is needed to optimize BES integration with BAVC for broader applicability. This study demonstrates BAVC as a scalable and mechanistically sound approach for TPH bioremediation in soil.

Advanced oxidation of polycyclic aromatic hydrocarbons in tropical soil: Self-catalytic utilization of natural iron contents in an oxygenation reactor supported with persulfate

The catalysts derived from natural iron minerals in the advanced oxidation process offer several advantages. However, their utilization in soil remediation is restricted due to the presence of soil impurities, which can inhibit the catalytic activity of these minerals. The soils in tropical regions exhibit lower organic matter content, limited cation exchange capacity, and are non-saline, this enhances the efficiency of utilizing natural iron minerals from tropical soil as a catalyst. In this regard, the catalytic potential of naturally iron-bearing tropical soil was investigated to eliminate phenanthrene (PHE), pyrene (PYR), and benzo[α]pyrene (B[α]P) using an oxygenated reactor supported with persulfate (PS). The system showed an efficient performance, and the removal efficiencies under the optimum conditions were 81 %, 73 %, and 86 % for PHE, PYR, and B[α]P, respectively. This indicated that the catalytic activity of iron was working efficiently. However, there were changes in the soil characteristics after the remediation process such as a significant reduction in iron and aluminum contents. The scavenging experiments demonstrated that HO• had a minor role in the oxidation process, SO4•− and O2•− emerged as the primary reactive species responsible for the effective degradation of the PAHs. Moreover, the by-products were monitored after soil remediation to evaluate their toxicity and to propose degradation pathways. The Mutagenicity test showed that two by-products from each PHE and B[α]P had positive results, while only one by-product of PYR showed positive. The toxicity tests of oral rat LD50 and developmental toxicity tests revealed that certain PAHs by-products could be more toxic from the parent pollutant itself. This study represents a notable progression in soil remediation by providing a step forward in the application of the advanced oxidation process (AOP) without requiring additional catalysts to activate oxidants and degrade pollutant PAHs from the soil.

Research on loss rules of oil and gas in preserved shale cores after open air exposure

There is a large amount of oil and gas loss in traditional conventional core samples. Revealing the rules of oil and gas loss is of great significance for restore the pristine oil content and oil component in the shale. In this study, four preserved shale cores with different thermal maturity (Ro = 1.01–1.53%) and different total organic carbon content (TOC = 1.69–5.48 wt.%) were selected. The samples are obtained from the first member of the Qingshankou Formation in the Gulong Sag. Nuclear magnetic resonance (NMR) T1–T2 mapping and thermal desorption gas chromatography (TD–GC, at a constant temperature of 300°C for 3 min) were performed on the preserved cores and their replicas that were exposed in open air for different times, to study dynamic loss process and the molecular composition changes of shale oil. The results show that during exposure, shale experiences a large amount of oil loss, with a loss ratio of about 42%–78%, and the higher the maturity, the greater the loss ratio. The oil loss is mainly contributed by free oil, with a loss ratio as high as 88%. The adsorbed oil content, however, remains basically unchanged and has a good positive correlation with the TOC of shale. Once the cores were crushed, the gaseous hydrocarbon in oil was basically evaporated in just 5 min. After long-term storage, 90% of the C14- light hydrocarbon is lost, while the C14+ heavy hydrocarbon experiences basically no loss. Therefore, effective and timely analysis of preserved shales is extremely important. The oil content of uncrushed shale cores characterized by NMR T1–T2 mapping is much greater than that of the crushed sample measured by TD-GC, which means that NMR T1–T2 mapping can be important method to evaluate the original fluid saturation of shale.

Process for desulfurization and demineralization of low rank coal using oxidation assisted froth floatation technique

This study reports the desulfurization and deashing of Hangu coal by air oxidation assisted froth floatation technique applying performic acid (H2O2+HCOOH) as co-oxidant and Fe ions as catalysts in aqueous solution. This process led to the removal of up to 78.08% of total sulfur (TS) and 50.3% of ash at 60 °C, 30 min, a 2:2 ratio of H2O2+HCOOH (v/v), and 0.10% of Fe ions concentration. The sulfur and ash removal followed Fenton mechanism, wherein hydrogen peroxide (H2O2) dissociated into hydroxyl ions (OH-) and hydroxyl radicals (OH.), facilitated by the dissociation of ferrous ions (Fe2+). The reaction of HCOOH with OH. resulted in the formation of performic acid or peroxyl radical, selectively oxidizing sulfur compounds to sulfone and sulfoxide. In the subsequent phase, coal froth floatation was employed with the addition of surfactant i.e. Triton X-100 (TX-100) and collector i.e. diesel oil (DO), resulting in the removal of up to 49.83% of TS and 43.79% of ash. This was achieved under optimized conditions, specifically with a concentration of 400 ppm solution of TX-100 in the solution and a volume of 0.2 mL for DO. The emulsion of TX-100 and DO for the floatation of coal is a suitable option because TX-100 established polar interactions and hydrogen bonding with the oxidized functionalities of coal, whereas the hydrocarbons of diesel oil get attached to the unoxidized coal matrix through hydrophobic interaction. Onwards, simultaneous oxidation assisted by froth floatation in a two-step batch process at pre-optimized parameters resulted in TS and ash removal of 88.8% and 82.6%, and 62.2% and 39.3% in the froth and tailings, respectively. SEM, FTIR and XRD analyses revealed structural and morphological changes, modifications in chemical functionalities and mineralogical changes in the coal sample. The process can be scaled up for the up-gradation of low grade coal for industrial and power generation purposes.

Impact of engineered water in modulating the wettability of oil–brine–rock system for improved oil recovery

AbstractLow salinity water injection stands as a progressive method for enhanced oil recovery, representing a current focus of extensive research. Understanding wettability alteration in crude oil is hindered by its intricate nature, posing a challenge for researchers. In order to better understand wettability alteration and underlying phenomena in an oil–brine–rock system, a fundamental study was carried out using pure hydrocarbon (aliphatic: n‐heptane; aromatic: toluene) and crude oil on quartz surface against engineered water consist of monovalent (NaCl) and divalent (MgSO4) salts in various compositions (NaCl:MgSO4: 100:0; NaCl:MgSO4: 0:100; NaCl:MgSO4: 75:25; NaCl:MgSO4: 50:50; NaCl:MgSO4: 25:75). The variables under investigation include temperature (25 to 65°C), pure hydrocarbons (toluene, n‐heptane), crude oil (Indian offshore), and brine (B1 to B5) with concentration (0 to 20,000 ppm). The findings show that when brine solution contains solely NaCl salt at a concentration of 2000 ppm, n‐heptane exhibits a minimum contact angle on quartz plate. Contrarily, toluene exhibits a low contact angle with a brine solution that only contains MgSO4 salt at a concentration of 2000 ppm. The intriguing finding is that when monovalent and divalent salts are equal (NaCl:MgSO4: 50:50) in the brine, crude oil exhibits the smallest contact angle on quartz. Additionally, temperature and contact angle are directly related for all oil types. The optimal brine for achieving the minimum contact angle on quartz surface is (B1)2000 for n‐heptane, (B2)2000 for toluene, and (B4)2000 for crude oil for the current study. The study findings indicate that the alteration in wettability due to brine composition and salinity varies among different oil samples, characterized by purely aliphatic, aromatic, and mixed components, and it depends on the type of salt compositions. Higher salts concentration minimally affects n‐heptane but influences toluene and crude oil contact angles.

PROMISING DEVELOPMENTS AND SCIENTIFIC TECHNOLOGICAL ACHIEVEMENTS IN GEOLOGICAL EXPLORATION IN THE MIDDLE EAST REGION

Technological and economic trends in the development of the oil and gas industry form promising directions for the development of geological research, oil and gas fields development and hydrocarbons production. Currently, in the world oil and gas production practice, there is a tendency to increase the share of involvement in the hard-to-reach and hard-to-recover reserves development, which results in the cost of geological exploration increasing. It is important to minimize these costs by improving existing and developing new technological solutions. Increasing the efficiency and knowledge intensity of new technologies being introduced is the most promising strategy for exploration activities, oil and gas fields development and exploitation.The current conditions for the exit of most foreign companies from the Russian sector of the oil and gas industry, including the search for potential oil locations, require the development or maintenance at the proper level of own innovative and knowledge-intensive solutions that ensure the further systematic development of the geological exploration sector. A potential vector in this direction could be technology transfer from foreign countries, including most of the Middle East and North Africa countries. The innovative activities of up stream in these countries (including in terms of geological exploration) determine the trends in the development of international geological exploration technologies, as well as potential foreign companies for the systematic institutionalization of mutually beneficial relations between Russian and foreign oil businesses.Saudi Arabia, Israel and Iraq companies develop promising innovative solutions for the oil and gas industry exploration sector, including attracting foreign technologies to their market. Saudi Arabian companies are the most active companies with a significant increase in the number of innovative technologies. The main focus of the innovative solutions developed by these companies for the geological exploration sector is: improving methods of laboratory and geophysical research, improving the quality of seismic exploration, as well as introducing mathematical modeling modern trends in geological exploration.

Marine Microbiota Responses to Shipping Scrubber Effluent Assessed at Community Structure and Function Endpoints.

The use of novel high-throughput sequencing (HTS) technologies to examine the responses of natural multidomain microbial communities to scrubber effluent discharges to the marine environment is still limited. Thus, we applied metabarcoding sequencing targeting the planktonic unicellular eukaryotic and prokaryotic fraction (phytoplankton, bacterioplankton, and protozooplankton) in mesocosm experiments with natural microbial communities from a polluted and an unpolluted site. Furthermore, metagenomic analysis revealed changes in the taxonomic and functional dominance of multidomain marine microbial communities after scrubber effluent additions. The results indicated a clear shift in the microbial communities after such additions, which favored bacterial taxa with known oil and polycyclic aromatic hydrocarbons (PAHs) biodegradation capacities. These bacteria exhibited high connectedness with planktonic unicellular eukaryotes employing variable trophic strategies, suggesting that environmentally relevant bacteria can influence eukaryotic community structure. Furthermore, Clusters of Orthologous Genes associated with pathways of PAHs and monocyclic hydrocarbon degradation increased in numbers at treatments with high scrubber effluent additions acutely. These genes are known to express enzymes acting at various substrates including PAHs. These indications, in combination with the abrupt decrease in the most abundant PAHs in the scrubber effluent below the limit of detection-much faster than their known half-lives-could point toward a bacterioplankton-initiated rapid ultimate biodegradation of the most abundant toxic contaminants of the scrubber effluent. The implementation of HTS could be a valuable tool to develop multilevel biodiversity indicators of the scrubber effluent impacts on the marine environment, which could lead to improved impact assessment. Environ Toxicol Chem 2024;43:1012-1029. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Role of keystone drives polycyclic aromatic hydrocarbons degradation and humification especially combined with aged contaminated soil in co-composting

Accumulation of persistent organic pollutants polycyclic aromatic hydrocarbons (PAHs) in soil has become a global problem. Composting is considered one of the more economical methods of soil remediation and is important for the resourceful use of wastes. Agroforestry waste is produced in huge amounts and is utilized at low rates, hence there is an urgent need to manage it. Here, leaf (LVS) or rice straw (SVS) was co-composting with aged contaminated soil to investigate bacteria interaction to PAHs degradation and humus formation. The degradation rate of high molecular weight PAHs (HMW-PAHs) in LVS and SVS reached 58.9% and 52.5%, and the low molecular weight PAHs (LMW-PAHs) were 77.5% and 65%. Meanwhile, the humus increased by 44.8% and 60.5% in LVS and SVS at the end of co-composting. The topological characteristics and community assembly of the bacterial community showed that LVS had higher complexity and more keystones than SVS, suggesting that LVS might more beneficial for the degradation of PAHs. The stability of the co-occurrence network and stochastic processes (dispersal limitation) dominated community assembly made SVS beneficial for humus formation. Mantel test and structural equation models indicated that the transformation of organic matter was important for PAHs degradation and humus formation. Degradation of HMW-PAHs led to bacterial succession, which affected the formation of precursors and ultimately increased the humus content. This study provided potential technology support for improving the quality of agroforestry organic waste composting and degrading PAHs in aged contaminated soil.

Pulsed Laser Manufactured Heteroatom Doped Carbon Dots via Heterocyclic Aromatic Hydrocarbons for Improved Tribology Performance.

Traditional laser-assisted method (top-down synthesis strategy) is applied in the preparation of carbon dots (CDs) by cutting larger carbon materials, which requires harsh conditions, and the size distribution of the CDs is seldom monodisperse. In this work, heteroatom-doped CDs, represented by N,S co-doped CDs (N,S-CDs), can be prepared successfully by pulsed laser irradiation of heterocyclic aromatic hydrocarbons-based small molecule compound solution. The friction coefficient (COF) of base oil PAO decreases from 0.650 to 0.093, and the wear volume reduces by 92.0% accompanied by 1 wt.% N,S-CDs addition, while the load-bearing capacity is improved from 100 to 950 N. The excellent lubrication performance is mainly attributed to the formation of a robust tribofilm via a tribochemical reaction between N,S-CDs and friction pairs, and the N,S-CDs can play a mending effect and polishing effect for worn surfaces. Furthermore, the lubricant containing heteroatom doped CDs are capable of being prepared in situ via pulsed laser irradiation of heterocyclic aromatic hydrocarbons in base oil, which can avoid the redispersed problem of nano-additive in base oil to maintain long-term dispersion, with COF of 0.103 and low wear volume ≈1.99 × 105 µm3 (76.9% reduction) even after standing for 9 months.

Drivers distinguishing of PAHs heterogeneity in surface soil of China using deep learning coupled with geo-statistical approach

Although numerous studies have reported the influencing factors of polycyclic aromatic hydrocarbons (PAHs) in surface soil from source, process or soil perspectives, the mechanism of PAHs heterogeneity in surface soil are still not well understood. In this study, the effects of 16 PAHs in surface soil of China sampled between 2003 and 2020 with their 17 “source-process-sink” factors at 1 km resolution (N = 660)) were explored using deep learning (eXtreme Gradient Boosting) to mine key information from complex dataset under the optimized parameters (i.e., learning rate = 0.05, maximum depth = 5, sub-sample = 0.8). It was observed that top five factors of 16 PAH had the largest cumulative contribution (i.e., from 84.8% to 98.1%) on their soil concentrations. PAH emission was the predominant driver, and its effect on soil PAH increases with increasing logKow. Soil was the second driver, in which clay can promote the partition of PAHs with low or middle logKow. However, sand can accumulate those congeners with high logKow. Moreover, the deep learning plus geo-statistical models (with low deviation for testing dataset (N = 283)) were capable of predicting soil PAH concentrations using their drivers with high accuracy. This study improved the understanding of the environmental fate and spatial variability of soil PAHs, as well as provided a novel technique (i.e., deep learning coupled with geo-statistics) for accurate prediction of soil pollutants.

Photocatalytic degradation of fluoranthene in soil suspension by TiO2/α-FeOOH with enhanced charge transfer capacity.

Polycyclic aromatic hydrocarbons (PAHs) in soil are potentially harmful to human health. However, the use of photocatalysis technology to treat soil contaminated with PAHs remains challenging. Therefore, TiO2/α-FeOOH composite photocatalyst has been synthesized by hydrothermal method and sol-gel method and applied to photocatalytic degradation of fluoranthene in soil. The morphology, elements, crystal structure, optical properties, electrochemical characteristics, and photocatalytic activity of TiO2/α-FeOOH have been characterized. Results showed that TiO2 is tightly fixed on the surface of α-FeOOH, and TiO2/α-FeOOH had higher photocatalytic activity on photocatalytic degradation of fluoranthene in soil under simulated sunlight. The degradation efficiency of TiO2/α-FeOOH is 3.0 and 4.8 times higher than that of TiO2 and α-FeOOH, respectively. This is attributed to enhanced photocatalytic ability by enhancing the transfer capacity of electrons and holes and broadening the spectrum absorption range. The highest degradation efficiency was achieved when the pH of the soil is neutral, the ratio of water/soil is 10:1, and the dosage of catalyst is 50mg/g. In addition, it was proved that •O2-, h+, and 1O2 are the main active substances in the photocatalysis of TiO2/α-FeOOH. The possible mechanism of a Z-type electron transfer structure was also proposed. The degradation products of fluoranthene were detected, and the degradation pathway was deduced.

Distribution, sources and health risk assessment of polycyclic aromatic hydrocarbons in urban soils under different landform conditions of Taiyuan, China

Public concern about polycyclic aromatic hydrocarbons (PAHs) is rising due to their potential carcinogenic, teratogenic, and mutagenic effects. This study assessed PAHs in Taiyuan City’s plain and mountain soil, investigating concentrations, distribution, sources, and carcinogenic risk. Σ21PAHs concentrations in plain topsoil ranged from 133.2 to 6,410.6 ng/g (mean 1,444.7 ng/g), and in mountain soil from 66.5 to 2,250.2 ng/g (mean 585.5 ng/g). Approximately 55.1% of plain and 19.0% of mountain soil samples had contamination levels exceeding 600 ng/g. In plain soil, 4-ring and 5-ring PAHs dominated, while 2-ring and 3-ring PAHs were prevalent in mountain soil. Polluted areas in Taiyuan were primarily centered in the central-north, with higher content closer to industrial or business districts. PAH isomer ratios and principal component analysis/multiple linear regression (PCA/MLR) indicated coal combustion as the main PAH source, followed by coke production, vehicle emissions, and biomass combustion. Incremental lifetime cancer risks (ILCRs) showed Taiyuan’s PAH-related cancer risks were generally low, though heavily contaminated areas exhibited moderate risks. Plain regions had three times higher cancer risk than mountains, with children facing higher risk than adults. These findings highlight the need to consider PAH pollution while enhancing urban environmental quality.

The effect of oil pollution on community structure of benthic macro ‎invertebrates in the northwest of the Persian Gulf ‎ ‎(Case study: Jafari creek)‎

<p>This study evaluates the contamination levels of heavy metals and petroleum hydrocarbons in Jafari ‎Creek sediments and the effect of these pollutions on Macrobenthos in 2017. Studies to understand ‎the effect of heavy metal Cadmium, Chromium, Nickel, Lead, Selenium, Zinc, Copper, and ‎Vanadium, and 16 hydrocarbon compounds, organic material, and soil texture on the population of ‎Jafari Creek Macrobenthos in five stations along the estuary and analyzed using standard ‎procedures. The 4 identified Macrobenthos included Bivalvia with 9 species, Gastropoda with 8 ‎species, Crustacea with 7 species, and Polychaeta with 6 species totaling Macrobenthos 3645.14 per ‎square meter. The dominant class was Polychaetes (53.9%), followed by Bivalvia (23.2%), ‎Gastropoda (9.93%), and Crustaceans (15.8%), with slightly different (P<0.05), were in the second ‎and third class. Among the studied metals, zinc, chromium, and nickel had the highest ‎concentration. Among the hydrocarbons, Anthracene at station 1, Fluorene at station 2, ‎Phenanthrene and Dibenzo [A, H] Anthracene at station 3, and Fluoranthene at station 4 with a ‎concentration between <0.01- 0.091 ppm had the highest value. The highest and lowest heavy metal ‎concentrations were measured at station 4 (215.54 ± 14.58 ppm) and station 1 (102.39 ± 24.15 ‎ppm), respectively. In return, stations 1 (0.339 ± 0.074 ppm) and 4 (0.196 ± 0.078 ppm) had the ‎highest and lowest concentration of hydrocarbons, respectively. Regarding the number of identified ‎Macrobenthos, stations 3 and 2, with 1738.64 and 333.28 n/m2 had the highest and lowest numbers, ‎respectively. The class of Crustacea had a positive correlation with zinc, copper, and lead metal and ‎a negative correlation with Selenium. Polychaeta was positively correlated with cadmium and ‎vanadium. Gastropoda had a negative correlation with vanadium and chromium, a positive ‎correlation with lead and hydrocarbons, and Bivalvia correlated negatively with lead and zinc and ‎had a correlation with vanadium. Considering that the areas around Jafari Creek are an industrial, ‎petrochemical, and economic region considered one of the important catchments in the province of ‎Khuzestan, the sediments, water, and animal tissues must be periodically the analysis of heavy ‎metals and oil hydrocarbons should be considered.‎</p>