Concentrations Of Hydrocarbons Research Articles

Mapping of hydrocarbon condensation onset temperature and its sensitivity analysis for Exhaust Gas Recirculation (EGR) cooler

Exhaust Gas Recirculation (EGR) cooling technology is one of the key technologies of the engine to meet the Euro 7 emission standard. Nevertheless, the hydrocarbon (HC) condensation in the cooler leads to uncontrolled thermal-hydraulic performance, and the onset temperature of HC condensation is still debated, which is one of the obstacles to implementing the Euro 7 standard. Here, we first established a database of key parameters (carbon number, concentration, and pressure); then theoretically calculated the onset temperatures of various condensation types (wall condensation, heterogeneous nucleation, and homogeneous nucleation), plotted the entire map and verified its veracity; and finally, elucidated the contribution of each parameter through sensitivity analysis. The results show that (i) HC species are C12 to C25, from 25 to 1717 ppm concentrations, and pressures are from 1 to 4 bar. (ii) The map diagrams for the onset temperature of HC condensation have broad applicability and strong practicality. (iii) The temperature ranges of the onset of wall condensation, heterogeneous nucleation, and homogeneous nucleation are from 4 to 218 °C, from 1 to 209 °C, and from −6 to 195 °C, respectively. (iv) Carbon number has the most significant contribution, followed by HC concentration and pressure. The results can provide a valuable reference for more accurate EGR cooler design and management.

Numerical investigation of soot formation in methane/n-heptane laminar diffusion flame doped with hydrogen at elevated pressure

The addition of hydrogen in a dual-fuel mode based on natural gas and diesel offers great potential for improving engine efficiency and reducing emissions. Therefore, detailed numerical simulations have been used to explore the effects of soot formation characteristics of natural gas-diesel dual-fuel engines doped by hydrogen at elevated pressure. Numerical simulations are compared with available experimental data, the effects of H2 addition on soot formation in laminar CH4 + n-heptane, H2 + CH4 + n-heptane, FH2 + CH4 + n-heptane diffusion flames at 2, 4, 6 and 8 atm are simulated, FH2 is added to separate the H2 chemical effects. The results show that the dilution and thermal effects of H2 inhibit soot formation, while the chemical effects of H2 promote soot formation under different pressures. The addition of H2 increases the concentration of H and OH radicals, which promotes the formation of C2H2 and benzene (A1). By simplifying the reaction path and analyzing the production rate of A1, the mechanism of H2 addition to promote A1 formation is illustrated. The concentrations of polycyclic aromatic hydrocarbon (PAH) pyrene (A4), benzo(ghi)fluoranthene (BGHIF) and benzo(a)pyrene (BAPYR) are inhibited at higher pressures that result in lower inception and condensation rates. Therefore, the increase of hydrogen abstraction acetylene addition (HACA) rate is the main reason for the increase of soot formation under chemical effects. While the O2 oxidation rate decreases and the OH oxidation rate increases, that is due to the decrease of O2 concentration and the increase of OH concentration in the soot formation area under chemical effects.

Alkanols Regulate the Fluidity of Phospholipid Bilayer in Accordance to Their Concentration and Polarity.

In spite of the widespread use of alkanols as penetration enhancers, their effect on vesicular formulations remains largely unexplored. These can affect the stability and integrity of the phospholipid bilayers. In this study, we have investigated the interaction of linear (ethanol, butanol, hexanol, octanol) and branched alkanols (t-amylol and t-butanol) with three phospholipids (soya lecithin, SL; soy L-α-phosphatidylcholine, SPC; and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC). Thermodynamic and structural aspects of these interactions were studied as a function of the alkanol concentration and chain length. Our interpretations are based on isothermal titration calorimetry (ITC) and dynamic light scattering (DLS) experiments. We observed one-site interactions wherein hydroxyl and acyl groups interacted with the polar and nonpolar regions of the phospholipid, respectively. The stability and structural integrity of bilayers appeared to be dependent upon (a) the hydrocarbon chain length and concentration of alcohols, and (b) the degree of unsaturation in the phospholipid molecule. We found that these interactions triggered a reduction in the enthalpy which was compensated by increased entropy, keeping free energy negative. Drop in enthalpy indicates reversible disordering of the bilayer which enables the diffusion of alcohol without triggering destabilization. Ethanol engaged predominantly with the interface, and it resulted in higher enthalpic changes. Interactions became increasingly unfavorable with longer alcohols - a cutoff point was recorded with hexanol. The overall sequence of membrane disordering capability was recorded as follows: ethanol < butanol < octanol < hexanol. Octanol's larger size restricted its penetration in the bilayer, and hence it caused less enthalpic changes relative to hexanol. This could also be verified from the trends in the area ratio of these vesicles obtained from the DLS data. Branched alkanols displayed a lower binding affinity with the phospholipids relative to their linear counterparts. These data are useful while contemplating the inclusion of short-chain alcohols as penetration enhancers in phospholipid vesicles.

Response of petroleum-contaminated soil to chemical oxidation combined with biostimulation

In this study, a microcosm experiment was conducted to investigate the effects of Na2S2O8 preoxidation combined with biostimulation on petroleum-contaminated soil remediation. The response of microbial community during this process was explored using BIOLOG ECO microplate carbon utilization method and 16 s rDNA high-throughput sequencing. The results showed that use of 10 mg/g Na2S2O8 removed 19.8 % of the petroleum hydrocarbons, reduced soil biotoxicity and did not affect soil microbial activity compared to other concentrations. Therefore, sodium persulfate of ca. 10 mg/g was used to oxidize petroleum in soil before the biostimulation experiment with organic and inorganic fertilizers. Our finding showed that the content of total petroleum hydrocarbons (TPHs) in soil was reduced by 43.3 % in inorganic fertilizer treatment after 60 days. The results of BIOLOG ECO microplate carbon utilization analysis and 16 S rDNA high-throughput sequencing further confirmed that biostimulation quickly restored the microbial activities in oxidant treated soil. The main marker bacteria in chemical oxidation combined with biostimulation remediation were Arthrobacter and Paenarthrobacter, and their relative abundances were both significantly negatively correlated with the content of petroleum hydrocarbons in soil.

Parameterization of H2SO4 and organic contributions to volatile PM in aircraft plumes at ground idle

ABSTRACT Volatile Particulate Matter (vPM) emissions are challenging to measure and quantify, since they are not present in the condensed form at the engine exit plane and they evolve to first form in the aircraft plume and then continue to grow and change as they mix and dilute in the ambient atmosphere. To better understand the issues associated with the initial formation and growth of vPM, a modeling study has been undertaken to examine several key parameters that affect the formation and properties of the vPM that is created in the initial cooling and dilution of the aircraft exhaust. A modeling tool (Aerosol Dynamic Simulation Code, ADSC) that was developed and enhanced over a series of past research projects supported by NASA, DoD’s SERDP/ESTCP, and FAA was used to perform a parametric analysis of vPM. The parameters of fuel sulfur content (FSC), emitted condensable hydrocarbon (HC) concentrations, and the species profile of the HCs were used to construct a computational matrix that framed a wide range of expected parameter values. This computational matrix was executed for two representative commercial aircraft engines at ground idle and results were obtained for distances of 250 m and 1000 m downstream. From prior results, the most significant vPM emissions occur at the lowest power settings, so an engine power condition of 7% rated thrust was used. A primary goal of the parametric study is to develop an updated vPM modeling methodology and also to help interpret data collected in experimental campaigns. The parameterization proposed here allows the vPM emission composition and particle numbers to be estimated in greater detail than current methods. The aim is to provide additional understanding on how the vPM properties vary with fuel and engine parameters to increase the utility of vPM predictions. Implications: Volatile Particulate Matter (vPM) is an important contribution to the total PM emitted by aviation engines. While vPM is not currently a part of engine emissions certification regulations, vPM is used in aviation environmental impact assessments and for air quality modeling in and around airports. Current methods in use, such as FOA, were developed before many recent advances in experimental data acquisition and in understanding of vPM processes. The parameterization proposed here allows the vPM emission composition and particle numbers to be estimated in greater detail than current methods. These estimates can be used to develop inventories and provide a better estimate of total emission for most aviation engines. Its use in international regulatory tools can inform possible future regulatory actions regarding vPM.

Investigation of the utilization of forest woodchips in a commercial small-scale open-top gasifier

The present work investigates the gasification of forest woodchips, which also contain needles, branches and cones, in an 85-kW open-top gasifier with 60 % to 100 % load. This lower quality fuel has higher contents of ash, bark and fines compared to typical requirements of commercial small-scale gasifiers. The woodchips were utilized in unsieved and sieved (> 10 mm) fraction. By using gas analysis and temperature measurements at a high local and temporal resolution, three main novel results were found: 1) The results of this work confirm that preferential paths in the fuel bed, caused by the fines content, led to a worse gas quality. The positive effects of a load reduction (i.e., increasing hydrogen and decreasing tars contents) were not found with the unsieved fuel. 2) Opposite trends for the methane concentration with the load were found with unsieved and sieved fuel. The preferential paths probably prevented the complete decomposition of longer-chain hydrocarbons and increased the intermediate product methane, while the non-methane hydrocarbon content reduced at a similar rate with both fuel fractions. 3) When using unsieved fuel, reducing the load massively decreased the fluctuations of the air mass flow and the total hydrocarbon content. With sieved fuel, however, a satisfying process stability was already achieved in all loads. Therefore, an appropriate load management was identified to enable the utilization of fuels with higher fines contents. With these new findings, forest chips in unsieved and sieved form can be successfully used in small-scale open-top gasification.

Evaluation and Modelling of Polycyclic Aromatic Hydrocarbon (PAH) Bioavailability in Soils Affected by Coal Tar Asphalt

There are large masses of coal tar asphalt present in old roads, containing high concentrations of polycyclic aromatic hydrocarbons (PAHs). Uncertainty surrounding the risk they pose causes problems during road reconstruction and for the reuse of the asphalt present. To help elucidate potential risks, a parsimonious linear equilibrium partitioning model for the bioavailability of PAHs in soils contaminated by tar asphalt particles was developed. Furthermore, a set of partitioning coefficients for PAHs between sampled coal tar binders and water were determined experimentally, as well as measurements of freely dissolved concentrations using polyoxymethylene samplers in batch tests and column recirculation experiments with various mixtures of different soils (peat and sandy loam) and tar asphalts. The model predictions of freely dissolved concentrations were conservative and within an order of magnitude of measurements in both batch and column tests. The model presented here only relies on soil organic carbon content and the fraction coal tar binder in the soil to model PAH partitioning. This model could be used for more realistic. low tier risk assessments towards rational prioritization of sensitive areas for risk reduction efforts.

Production of green diesel from waste cooking oil via catalytic deoxygenation reaction using metal doped eggshell catalyst

Abstract Green diesel production via catalytic deoxygenation of waste cooking oil (WCO) over metal doped eggshell catalyst was investigated in this work. The catalyst was prepared through liquid-liquid precipitation of 5 transition metal solutions and ground eggshell (ES) as the catalyst support. The prepared catalyst, Fe-ES, Cu-ES, Co-ES, Zn-ES, and Ni-ES were characterized using BET surface area and Scanning Electron Microscopy (SEM) analysis. BET surface area data and SEM images of the catalyst shows a promising catalyst physical properties that tailor to the deoxygenation reaction. Gas Chromatography Mass Spectrometry (GCMS) was used to determine the hydrocarbon composition of the oil yield product from the reaction. The reaction also produces gas, soap and liquid acid phase while the remaining unreacted WCO becomes coke. The percentage of all products and coke were calculated using mass balance. Deoxygenation of WCO with Ni-ES catalyst produced highest oil yield at 61.6% with the hydrocarbon content of 56.11%. Ni-ES also produced 22.9% coke; the least percentage compared to other catalyst. The findings proved that Ni-ES catalyst exhibited the highest conversion of WCO into gas and liquid product with a greater yield of oil and minimal coke formation. These findings demonstrate the feasibility and practicality of using eggshell catalysts as substitutes for commercial catalysts in green diesel production.

The kinetic and experimental study for the pyrolysis of hydrotreated and non-hydrotreated coking distillated fractions

AbstractThe purpose of this study is the pyrolysis of the distilled fractions obtained in the coking process as such and hydrotreated with the aim of diversifying the feedstock used in pyrolysis. The application of hydrotreating followed by pyrolysis, determines the reduction of the aromatic and olefinic hydrocarbons content in the feedstock, which leads to the improvement of the distribution of the reaction products and the decrease in the level of coke deposits, compared to the pyrolysis of non-hydrotreated distillate fractions. This study also aims to calculate the kinetic parameters of the pyrolysis process for non-hydrotreated and hydrotreated coking fraction at three equivalent temperatures: T = 680 °C, T = 695 °C, T = 705 °C. Graphical abstract

Catalytic solvothermal liquefaction of kitchen waste over iron-based catalysts addition and two-step method to produce high-quality fuels

The disposal of kitchen waste (KW) is a wide concern because of its high moisture content, foul odor, and low energy density. Solvothermal liquefaction (STL) can directly convert KW to bio-oil without pre-drying. This study investigated the effect of iron-based catalysts (Fe, Fe2O3, and Fe3O4) and a catalytic two-step method on bio-oil production, heteroatom distributions (N and S), and pollutant decompositions during STL of KW. From the comparison of three iron-based catalysts, the catalysis of metallic Fe significantly enhanced the bio-oil yield and quality, resulting in the highest yield (52.30 %) and a high heating value (35.86 MJ/kg) of bio-oil. Meanwhile, metallic Fe noticeably increased the fraction of lighter molecules in bio-oil to 71.30 %. During the catalytic two-step method process, the nitrogen and sulfur in the raw material were primarily transferred to the aqueous phase in the form of NH4+ and SO42-. The introduction of iron-based catalysts significantly promoted the esterification and reduction reactions. The bio-oil exhibited the highest ester content (77.96 %) when Fe3O4 was present while adding metallic Fe catalyst resulted in the highest hydrocarbon content of 28.16 %. Finally, a potential reaction pathway and mechanism of the catalytic STL of KW were proposed and discussed comprehensively. This study validates the use of iron-based catalysts and a two-step method to improve the yield and quality of bio-oil. This method reduces heteroatom content through associated hydrogenation and reduction reactions, demonstrating its potential for upgrading bio-oil into high-quality fuel.

Catalytic pyrolysis of torrefied biomass with molecular sieve catalysts to produce hydrocarbon rich biocrude

AbstractThe downstream processing of biocrudes obtained from direct biomass pyrolysis poses significant challenges due to stability issues, necessitating costly upgrading for further coprocessing with refinery feeds. This study examines the impact of torrefaction pretreatment on pyrolysis product distribution and biocrude composition using sawdust (SD) and groundnut shell (GS) feeds. Torrefaction was conducted at varying temperatures (200, 250 and 300°C) for 30 min under different reactor conditions. Increasing the severity of torrefaction resulted in decreased biocrude yields with reduced water content and gas formation, particularly evident with GS. A torrefaction temperature of 250°C and 30 min of pretreatment yielded higher phenolics and hydrocarbons. This increase in phenolics can be attributed to lignin enrichment during torrefaction, which, in the presence of a catalyst, undergoes deoxygenation leading to hydrocarbon formation. The influence of feed particle size, whether in powder or pellet form, on biocrude yield and composition was found to be minimal. Catalytic pyrolysis of SD using molecular sieve catalysts yielded the highest hydrocarbon (42%) and aromatic content (44%) at catalyst to biomass ratios of 1:1 and 2:3. The combination of torrefaction and pyrolysis was shown to enhance the quality of biocrude by increasing its hydrocarbon content, but at the expense of lower liquid yields. Experimental observations were supported by statistical analysis tools such as principal component analysis, which assessed pyrolysis product yields and composition.

Controlling the morphology of polycrystalline diamond films via seed density: Influence on grain size and film texture

Controlling the morphology of polycrystalline diamond (PCD) films is crucial for various applications, including thermal management and quantum sensors. PCD films are typically produced by plasma-enhanced chemical vapor deposition on substrates seeded with nanodiamonds. Different film morphologies can be achieved by controlling growth rates of crystal-forming facets, which is commonly managed through deposition temperature and hydrocarbon concentration in the plasma. However, the impact of seed density on film morphology remains largely unexplored. In this study, we observed that reducing seed density on silicon substrates has a similar effect on PCD film morphology as increasing hydrocarbon concentration in the plasma. Specifically, as seed density decreases, deposition rate increases, and film texture transitions from (1 1 1) to (1 0 0), followed by the formation of large grains with (1 0 0) facets surrounded by clusters of small grains. These changes were observed using electron microscopy, Raman spectroscopy, and X-ray diffraction. To explain our results, we hypothesize that the silicon–plasma interface surrounding the growing diamond seeds acts as a diamond precursor source. Our proposed explanation requires relatively long precursor migration lengths compared to those assumed in standard diamond deposition theory. Finally, we also propose two new mechanisms for diamond precursor adsorption based on well-established physical phenomena and recent publications. Our findings may open new avenues in diamond research, applicable not only to polycrystalline but also to single-crystal diamond deposition.

Relationship between foliar polycyclic aromatic hydrocarbons (PAHs) concentrations and plant traits: Intracanopy variability for a broadleaf species in an urban environment

The emission of potentially harmful compounds, including polycyclic aromatic hydrocarbons (PAHs), and the resulting air pollution is a serious problem in modern cities. It is therefore important to develop mitigation strategies, such as “smart” planting of trees that act as sinks for PAHs. However, the intra-individual (within-tree) variability in leaf PAH concentrations remains unknown. In this paper, we studied 15 ornamental apple trees (Malus × moerlandsii ‘Profusion’) growing on a main street in a medium-sized city in Galicia (NW Spain). We determined the PAH concentrations at 12 canopy positions in each tree (2 orientations and 2 distances from the trunk at 3 heights), measured various ecological traits (specific leaf area [SLA], δ13C, stomatal density, fatty acid contents and leaf hairiness) and analyzed the variability in traits within the canopy in relation to PAH concentrations. We observed high intra-individual variability in the PAH concentrations and the leaf traits. Statistical analyses revealed that leaf height was the main source of variability both in the PAH concentrations and in the traits, mainly due to the leaf morphology, particularly to the SLA. Therefore, the ideal vegetation to remove PAHs would be high leaf biomass trees, not too tall and with a high proportion of shade leaves.

Mucor thermorhizoides—A New Species from Post-mining Site in Sudety Mountains (Poland)

Mucor representatives are mostly rapidly growing cosmopolitan soil saprotrophs of early diverged Mucoromycotina subphylum. Although this is the most speciose genus within the group, some lineages are still understudied. In this study, new species of Mucor was isolated from the post-mining area in southwestern Poland, where soil chemical composition analysis revealed high concentration of hydrocarbons and heavy metals. Phylogenetic analysis based on multigene phylogeny showed that the new isolate clusters distinctly from other Mucor species as a sister group to Mucor microsporus. New species Mucor thermorhizoides Abramczyk (Mucorales, Mucoromycota) is characterized by the extensive rhizoid production in elevated temperatures and formation of two layers of sporangiophores. It also significantly differs from M. microsporus in the shape of spores and the size of sporangia. M. thermorhizoides was shown to be able to grow in oligotrophic conditions at low temperatures. Together with M. microsporus they represent understudied and highly variable lineage of the Mucor genus.

Pyrolysis and catalytic upgrading of pine wood sawdust over modified biochar catalyst in a tandem microreactor

A series of novel catalysts were prepared by modifying biochar (BC) with different metal loading (Fe, Zn) and thermal activation in different atmospheres (CO2, H2O). The catalysts were further used to upgrade the pyrolysis vapor from pine wood sawdust, aiming to produce high-quality bio-oil. The modified biochar catalyst exhibited strong deoxygenation ability to acids and ketones in bio-oil and effectively converted lignin-derived compounds into aromatic hydrocarbons and phenols. Subsequently, the catalyst (BC-Fe-CO2) demonstrating the highest yields of phenols and aromatics was selected for condition optimization. Different catalytic temperatures and biomass-to-catalyst ratios were compared to determine the optimal conditions for producing high-quality bio-oil. Phenolics and aromatic hydrocarbons content in the bio-oil reached 70 % at the optimal condition and the selectivity of monocyclic aromatic hydrocarbons in aromatic hydrocarbons reached 77 %. The properties of the biochar catalysts were characterized using BET, SEM, XRD, and XPS. The superior performance of the modified BC catalysts not only relied on its enhanced surface area and porous structure but also due to active Fe sites. The detail reaction pathways of the bio-oil catalytic upgrading were also proposed. These findings underscore the potential of modified biochar in pyrolysis and catalytic upgrading for bio-oil with improved quality.

Enhanced Natural Attenuation Technique, Edaphic and Microbiological Changes in Oil-Impacted Soil of Odhiaje Community, Rivers State

Oil spills in the Niger Delta could exert environmental pressures on the soil component. We investigated the impacts of oil spills and the effect of the Enhanced Natural Attenuation (ENA) remediation method on contaminated soil and resident microbial populations in the Odhiaje community in Rivers State, Nigeria. Soil samples for microbiological studies were collected weekly during a 17-week remediation period, while those for edaphic parameters were taken before and after remediation, all at 4 sampling points (SPs). Serial dilution of the oil-impacted soils for microbial density enumeration was carried out according to standard methods. Results revealed that mean concentrations of Total Petroleum Hydrocarbon Contents (THC) (Sig.value = 0.009), SO42- ions (Sig.value = 0.001), and sand compositions (Sig.value = 0.045) all differed markedly across the sampling points at p&lt;0.05. Mean levels of EC (Sig.tvalue = 0.039) and ΣN (Sig.tvalue = 0.058) &amp; K+ ions (Sig.tvalue = 0.004) differed significantly before and after the remediation exercise at the 95% confidence interval. Application of nutrients was rapidly accompanied by microbial population increases, leading to the consumption of oil contaminants in soils to levels comparable to control over the remediation period. Total Heterotrophic Bacteria counts correlated with pH (r = 0.501) and SO42- ions (r = 0.500) (p&lt;0.05), and K+ ions (r = -0.800) (p&lt;0.01); Total Heterotrophic Fungi correlated with pH (r = 0.520) (p&lt;0.05), and Mg2+ ions (r = 0.820) (p&lt;0.01); Hydrocarbon Utilizing Bacteria correlated with available P (r = 0.530) and silt composition (r = -0.504) (p&lt;0.05), and K+ (r = 0.626) and Mg2+ ions (r = 0.733) (p&lt;0.01); and Hydrocarbon Utilizing Fungi correlated with K+ (r = 0.500) &amp; Mg2+ ions (r = 0.506) (p&lt;0.05). Results indicate improvement in C/N ratios and effectiveness of the current cost-effective bioaugmentation technique in the restoration of arable soil productivity in the Odhiaje community.

Energy strategy alteration, rather than toxicity itself, interferes with the population fluctuation of Brachionus plicatilis exposed to water-accommodated fractions (WAFs) of crude oil

Oil spills are reported to have conflicting impacts of either injury or resilience on zooplankton communities, and physiological plasticity is speculated to be the possible causative factor. But how? An explanation was sought by exposing the marine rotifer Brachionus plicatilis to a series of water-accommodated fractions (WAFs) of crude oil under controlled laboratory conditions, and population dynamics, which is the core issue for zooplankton facing external stress, were analyzed. The total hydrocarbon concentration of WAFs was quickly degraded from a concentration of 5.0 mg L−1 to half within 24 h and then remained stable. No acute lethality was observed; only motion inhibition was observed in the group treated with 10 %, 50 % and 100 % WAFs, which occurred simultaneously with inhibition of feeding and filtration. However, sublethal exposure to the WAFs concentration series presented stimulation impacts on reproduction and even the population of B. plicatilis. The negative correlation between motion and reproduction seemed to indicate that a shift in the distribution of individual energy toward reproduction rather than motion resulted in increased reproduction after exposure to WAFs. More evidence from transmission electron microscopy (TEM) revealed ultrastructural impairment in both the ovaries and cilia in each treated group, and imbalance in mitochondrial numbers was one of the distinct features of alteration. WAFs stress may alter the energy utilization and storage paradigm, as indicated by the significant elevation in glycogen and the significant decrease in lipid content after WAFs exposure. Further evidence from metabolomics analysis showed that WAFs stress increased the level of lipid metabolism and inhibited some of the pathways in glucose metabolism. Sublethal acute toxicity was observed only in the first 24 h with WAFs exposure, and an energy strategy consisting of changes in the utilization and storage paradigm and reallocation is responsible for the population resilience of B. plicatilis during oil spills.

Measuring ecological quality status in low-diversity Arctic intertidal foraminiferal assemblages using a diversity-based index

EcoQS assessment of the marine intertidal zone based on its fauna is challenging because the assemblages have a low diversity and consist of stress tolerant species. The new approach we propose is to pool foraminiferal diversity (effective number of species exp(H'bc)) across the whole intertidal zone including the salt marsh and tidal flat. In seven fjordheads studied in northern Fennoscandia, polycyclic aromatic hydrocarbon (PAH) concentrations indicated low levels of pollution (EcoQSPAH Excellent to Moderate). Jadammina or Balticammina dominated the salt marsh, Elphidium albiumbilicatum, Elphidium williamsoni, Elphidium clavatum, and Buccella frigida occurred in the tidal flat. Ovammina opaca thrived in both belts. While foraminiferal test abnormalities are often proposed to measure pollution impacts, we did not detect any correlation with PAHs. EcoQS based on foraminiferal diversity (EcoQSforam Excellent to Good) matched EcoQS based on PAHs suggesting that pooled foraminiferal diversity reliably measures intertidal EcoQS.

Recent Advances in Sample Preparation and Chromatographic/Mass Spectrometric Techniques for Detecting Polycyclic Aromatic Hydrocarbons in Edible Oils: 2010 to Present.

Polycyclic aromatic hydrocarbons are considered to be potentially genotoxic and carcinogenic to humans. For non-smoking populations, food is the main source of polycyclic aromatic hydrocarbons exposure. Due to their lipophilic nature, oils and fats rank among the food items with the highest polycyclic aromatic hydrocarbon content. Consequently, the detection of polycyclic aromatic hydrocarbons in edible oils is critical for the promotion of human health. This paper reviews sample pretreatment methods, such as liquid-phase-based extraction methods, adsorbent-based extraction methods, and the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, combined with detection techniques like mass spectrometry and chromatography-based techniques for accurate quantification of polycyclic aromatic hydrocarbons in edible oils since 2010. An overview on the advances of the methods discussed herein, along with a commentary addition of current challenges and prospects, will guide researchers to focus on developing more effective detection methods and control measures to reduce the potential risks and hazards posed by polycyclic aromatic hydrocarbons.

Investigation of the pollutant load of artisanal-refined gasoline in the Niger Delta region of Nigeria and its implications on air quality

In order to examine the gaseous pollutants generated by artisanal refined gasoline and the contribution to air pollution associated with such combustion in the Niger-Delta region of Nigeria, this study collected a sample of indigenously refined gasoline product each from thirty (30) different randomly selected artisanal camps in the Niger-Delta region and subjected all the collected samples to combustion. Fifty (50) ml of each gasoline sample was combusted at controlled conditions, and the concentrations of gaseous emissions from the process were measured using a combustion emission analyser. Pollutants characterised by the Department of Petroleum Resources which include sulphur dioxide (SO2), carbon monoxide (CO), oxides of nitrogen (NOx), hydrocarbons (HC) and carbon dioxide (CO2) were characterised. The average concentrations of the emissions were 211.50 mg/m3, 7.18 mg/m3, 17.51 mg/m3, 3011.33 mg/m3, and 500.39 mg/m3 for CO, NOx, SO2, CO2, and HC respectively. The concentrations of SO2 and NOx measured were within the Federal Environmental Protection Agency (FEPA) set limits for combustion emissions from stationary sources but breached World Health Organization (WHO), World Bank and Environmental Guidelines and Standard for Petroleum Industry in Nigeria (EGASPIN) set limits. The concentrations of CO and HC exceeded FEPA, WHO, World Bank and EGASPIN set limits and hazardous on Air Quality Index (AQI) classification. Elevated concentrations of CO and HC in the atmosphere pose a major threat to ambient air quality and human health, especially in locations where artisanal-refined fuel is predominantly utilised. Associated risks include poor visibility, occurrence of acid rain, blood poisoning and cancer-related diseases. In addition to these effects are the worsening global warming crises associated with CO2 emission, a major product of fossil fuel combustion.