Identification Of Hydrocarbons Research Articles

Concentrations, source identification and eco-toxicological risk of polycyclic aromatic hydrocarbons in agricultural soils of Kenya, Eastern Africa

This study evaluated the concentrations, distribution, source and potential toxicological risk of 16 polycyclic aromatic hydrocarbons (PAHs) in agricultural soils in Kenya, East Africa. A total of 69 soil samples were analysed from five agricultural sites. Matrix solid-phase extraction was used for sample extraction before analysis using high-performance liquid chromatography. A total organic carbon analyser was used to assess the organic carbon content of all of the soil samples. The overall concentrations of PAHs varied from 2593.05 ng/g (Maai Mahiu) to 4356.15 ng/g (Mount Suswa) with a mean value of 3353.04 ± 2179.81 ng/g. Lower-molecular-weight (2-, 3- and 4-ring) PAHs were dominant in the soils. Anthracene had the highest mean concentration with a value of 1048.92 ng/g and ranged from 614.37 ng/g in Narok to 2416.95 ng/g in Mount Suswa. Identification of potential sources of PAHs revealed that pollution from PAHs in Kenyan soil samples was primarily derived from pyrogenic sources linked to biomass combustion and from vehicle and coal combustion. The risk assessment indicated a high eco-toxicological risk associated with the majority of the 16 PAHs in Kenyan agricultural soils. All of the RQ∑16PAHs (NCs) in all of the study sites showed values higher than 800. Similarly, all of the RQ∑16PAHs (MPCs) were also found to be greater than 1.00 in all study sites, which indicated potential risk. Therefore, certain measures need to be established to control and mitigate pollution.

SIMULATION OF INTERACTION OF ELECTROMAGNETIC WAVES WITH ANISOTROPIC MEDIA UNDER HYDROCARBON DEPOSITS IN THE MODE OF VIDEO-PULSE SIGNALS

The article presents the simulation of the interaction of electromagnetic waves in the mode of video pulse signals with the medium over hydrocarbon deposits. The analysis of the spectra of reflected video pulse signals from the medium over hydrocarbons is carried out. A study of the propagation of radio waves over hydrocarbons is carried out within the framework of a quasihydrodynamic approximation. The choice of the frequencies of video pulse signals is due to the determination of media characteristics over deposits at great depths compared to the surface of the earth. The spectrum of reflected signals from an anisotropic medium above a hydrocarbon deposit in the mode of video pulse signals can be used to determine the electrodynamic characteristics of the medium over the deposit over a wide range of frequencies of probed signals, dielectric permittivities and conductivity of media. The ability to reconfigure a geo-prospecting device from one mode to another (pulse width adjustment) in the presence of a deposit complements the functionality to search for hydrocarbon deposits. Electromagnetic methods for the search for and identification of hydrocarbons can be improved by obtaining information about objects through several information channels, which allows them to be identified with a sufficiently high level of reliability on the background of the underlying environment. The depths of occurrence, the resolving power in the investigated frequency range are determined. The results of the research can be used to develop new electromagnetic methods for the search for hydrocarbon deposits.

Atomic Force Microscopy Identifying Fuel Pyrolysis Products and Directing the Synthesis of Analytical Standards.

Here we present a new method that integrates atomic force microscopy (AFM) with analytical tools such as high-performance liquid chromatography (HPLC) with diode-array ultraviolet-visible (UV) absorbance, and mass spectrometry (MS) along with synthetic chemistry. This allows the detection, identification, and quantification of novel polycyclic aromatic hydrocarbons (PAH) in complex molecular mixtures. This multidisciplinary methodology is employed to characterize the supercritical pyrolysis products of n-decane, a model fuel. The pyrolysis experiments result in a complex mixture of both unsubstituted as well as highly methylated PAH. We demonstrate the AFM-driven discovery of a novel compound, benz[ l]indeno[1,2,3- cd]pyrene, with the chemical structure assignment serving as input for the chemical synthesis of such molecule. The synthesis is verified by AFM, and the synthesized compound is used as a reference standard in analytical measurements, establishing the first-ever unequivocal identification and quantification of this PAH as a fuel product. Moreover, the high-resolution AFM analysis detected several five- to eight-ring PAH, which represents novel fuel pyrolysis and/or combustion products. This work provides a route to develop new analytical standards by symbiotically using AFM, chemical synthesis, and modern analytical tools.

Pollution Characteristics and Source Identification of Polycyclic Aromatic Hydrocarbons and Phthalic Acid Esters During High Water Level Periods in the Wuhan Section of the Yangtze River, China

Persistent organic pollutants (POPs) have been detected extensively in water and sediments in China, causing potential risks to the environment and human beings. In this study, the content level, distribution characteristics, and pollution sources of PAHs and PAEs in the water and sediments collected from 15 sites in the Wuhan section of the Yangtze River in August of 2016 were analyzed systematically. The following conclusions were made. The total PAHs concentrations were 20.8-90.4 ng·L-1 (mean value 40.7 ng·L-1) in water and 46.1-424.0 ng·g-1 (mean value 191.8 ng·g-1) in the sediments, while for PAEs, they were 280.9-779.0 ng·L-1 (mean value 538.6 ng·L-1) in water and 1346.2-7641.1 ng·g-1 (mean value 3699.5 ng·g-1) in the sediment. Both PAH and PAE concentrations in water meet the Chinese national water environmental quality standard (GB 3838-2002) with a low degree of pollution. PAH monomers with two to three rings were dominant in water, while those with two to three rings and four rings were dominant in the sediment. DEHP and DBP were the dominant PAE pollutants in both the water and sediment. The ratio and principal component analysis showed that the main source of PAHs in water and the sediment were the emission from coal, biomass combustion, and petroleum sources, while the main sources of PAEs include the plastic and chemical industries and municipal solid wastes. Two types of POPs (PAHs and PAEs) in water and sediment have potentially detrimental effects on human health and monitoring needs to be strengthened. This research provides basic data and technical support for the protection of the Yangtze River.

Improving rigor in polycyclic aromatic hydrocarbon source fingerprinting

ABSTRACTSource identification of polycyclic aromatic hydrocarbons in environmental samples has advanced greatly in the last 20 years and continues to advance. To realize potential benefits and avoid possible pitfalls, however, great care is needed as one applies published diagnostic tools to data sets. This commentary reflects some recent observations, concerns, and recommendations.

Source identification of Polycyclic Aromatic Hydrocarbons (PAHs) in the urban environment of İstanbul

In this study, İstanbul-Tuzla Region atmosphere is selected as the working area because of this region contains shipyards and shipyard-related side product industries. To examine the PAHs as atmospheric inputs, 46 ambient air samples were collected in Tuzla region of Istanbul, Turkey at 2010. The sample collection was carried out as monthly. Additionally, the volume of the air was drawn and meteorological data recorded. The PAH concentrations were classified as hot and cold season samples. Due to the particle-bond character of PAHs and condensation in cold, the high concentrations were encountered in winter months. Monthly average total PAH concentrations fluctuated between 7.4 ng m-3 (in March)-0.05 ng m-3 (in August). The concentrations of total PAHs in cold season were almost hundred times higher than those in hot season. The fossil fuel (gasoline and diesel fuel) combustion was found to be the main source of PAHs.

Benzo(a)Pyrene Equivalency and Source Identification of Priority Polycyclic Aromatic Hydrocarbons in Surface Sediments from Yamuna River

ABSTRACTIdentification of polycyclic aromatic hydrocarbons (PAHs) sources in the environmental compartments is crucial, but there is a need for appropriate management and remediation plan in the environment. PAHs can provide useful information, because they have been utilized for source apportionment. In this study, priority 16 PAHs were determined in sediments from Yamuna River in Delhi for the assessment of their possible sources. Among 16 PAHs, the dominant compounds were fluoranthene, chrysene, fluorine, and pyrene, and their sum accounted for more than 96% of the total 16 priority PAHs. The concentrations of ∑16PAHs at locations between upstream and downstream were not showing any considerable spatial gradient. The concentration of seven probable carcinogenic PAHs ranged 236–6230 µg kg−1 with the mean value of 1897 ± 1740 µg kg−1, and accounted for 40% of the ∑16PAHs. Benzo(a)pyrene toxic equivalent factors (TEFs) used for the quantification of relative toxicity potential of priority PAHs in terms of BaP toxicity equivalency (BaPTEQ) were presented. Homolog profiles demonstrated the dominance of two-, three-, and four-ring PAHs. Composition profile and selected concentration ratios of PAHs were used as diagnostic tools for the identification of possible emission sources of PAHs. The study suggested the pyrogenic activities of petroleum, coal, and biomass combustions as a major source of PAH contamination in the river. However, marginally petrogenic sources from automobile workshops and accidental spillage cannot be ruled out. The observed levels of total PAHs and their toxicity equivalency in sediments were more or less comparable with similar studies carried out worldwide.

Seasonal variation, phase distribution, and source identification of atmospheric polycyclic aromatic hydrocarbons at a semi-rural site in Ulsan, South Korea.

Polycyclic aromatic hydrocarbons (PAHs) in gaseous and particulate phases (n = 188) were collected in Ulsan, South Korea, over a period of one year (June 2013‒May 2014) to understand the seasonal variation and phase distribution of PAHs as well as to identify the seasonal PAH emission sources. The target compounds were the 16 US-EPA priority PAHs, with the exception of naphthalene, acenaphthylene, and acenaphthene. Winter and spring had the highest and lowest PAH concentrations, respectively. The mean of the Σ13 PAHs in the gaseous phase (4.11 ng/m3) was higher than that in the particulate phase (2.55 ng/m3). Fractions of the gaseous or 3- and 4-ring PAHs (i.e., Flu, Phe, and Ant) were high in summer, and those of the particulate or 5- and 6-ring PAHs (i.e., BkF, BaP, Ind, DahA, and BghiP) increased in winter. Gas/particle partitioning models also demonstrated the increased contributions of the particulate PAHs in spring and winter. Source identification of PAHs was undertaken using diagnostic ratios, principal component analysis, and positive matrix factorization. The results indicated that pyrogenic sources (e.g., coal combustion) were dominant in winter. Other types of pyrogenic (e.g., industrial fuel combustion) and petrogenic sources were the main PAH sources in summer and autumn. The influence of both sources, especially in summer, might be due to seasonal winds transporting PAHs from the industrial areas. Two types of pyrogenic sources, diesel and coal combustion, were identified as the main PAH sources in spring. This study clearly demonstrates a source-receptor relation of PAHs at a semi-rural site in a heavily industrialized city.

Polycyclic aromatic hydrocarbons (PAHs) in sediments from a typical urban impacted river: application of a comprehensive risk assessment.

Soweto and Lenasia, the most densely populated area of South Africa, is simultaneously a thriving metropolis, with a fair share of people still living in squalor conditions directly dependant on the natural resources. Because of industrialisation the populace and environment in this urban area are exposed to various pollutants. The aquatic environment was selected as a proxy to study the effect of industrial pollution in this area. The concentrations, source identification, and various environmental risks of polycyclic aromatic hydrocarbons (PAHs) were determined in sediments of the upper reaches of the Klip River. Composite sediment samples collected in low-flow conditions in 2013 and 2014 ranged from 270-5400 ng/g. The PAHs in this aquatic ecosystem were dominated by 4-ring congeners and could be attributed to combustion of organic fuels by chemical mass balance. Heavy traffic and industrial complexes in the northern part of the study area were responsible for the PAH fingerprints. Probable adverse effects such as toxicity to benthic biota were proven after comparison with international sediment quality guidelines (SQG) both survey years. Toxic equivalence quotients (TEQs) calculated for the sediments using fish potency factors (FPFs) were up to 30 times greater than the Canadian guideline for dioxin-like compounds, indicating high probability of carcinogenic effect to fish mediated through the aryl-hydrocarbon receptor. Finally, sediments in the area posed moderate to high ecological risk, which corroborates the other toxicity assessments. The advantage of investigating multiple risk endpoints, is the comprehensive results obtained that allows for a more realistic representation of the study area. Consequently more aspects are kept into account that results in better conclusions.

Identification and quantification of polycyclic aromatic hydrocarbons generated during pyrolysis of sewage sludge: Effect of hydrothermal carbonization pretreatment

Hydrothermal carbonization (HTC) is of increasing importance to improve fuel quality and dewaterability of sewage sludge (SS). In this study, the effect of HTC of SS on the formation of 16 priority polycyclic aromatic hydrocarbons (PAHs) during pyrolysis, the primary stage of combustion, were investigated. The results showed that HTC improved fuel quality of SS while the PAHs were concentrated in the resultant hydrochar. Hydrochar pyrolysis generated less tar (3.49–8.82%) than SS pyrolysis (4.73–14.83%) while the PAHs yields in hydrochar pyrolytic tar were higher than the yields of SS pyrolytic tar, ranging from 104.93 mg/kg to 1199.07 mg/kg in the temperature range of 500–800 °C. In addition, the proportions of highly toxic middle molecular weight (MMW) and high molecular weight (HMW) PAHs in hydrochar tar were much higher than that for SS. As for the pyrolytic char, the PAHs in hydrochar char were also far higher than that in SS pyrolytic char at the temperature higher than 650 °C. These differences resulted in more total PAHs emissions and higher toxic equivalent quantity (TEQ) from hydrochar pyrolysis than those from SS pyrolysis in the temperature range of 500–800 °C. This study indicated that more attention should be paid to control PAHs emission energy recovery from hydrothermally treated SS.

Determination of polycyclic aromatic hydrocarbons with molecular mass 302 in Standard Reference Material 1597a by reversed-phase liquid chromatography and stop-flow fluorescence detection.

The identification of isomeric polycyclic aromatic hydrocarbons (PAHs) in complex samples via reversed-phase liquid chromatography (RPLC) with fluorescence detection (FL) is normally based on matching the chromatographic retention times of suspected peaks of interest with reference standards. Since no spectral information is obtained during the chromatographic run, the accurate identification of co-eluting PAHs with similar chromatographic behaviors requires confirmation with additional chromatographic methods. This is particularly true for the analysis of PAH isomers with the relative molecular mass (MM, g/mol) 302. The work presented here explores the information content of room-temperature fluorescence spectra for the analysis of PAHs with MM 302 in the Standard Reference Material (SRM) 1597a. Fluorescence spectra were recorded under stop-flow conditions with the aid of a commercial HPLC system. Of the 21 MM 302 PAHs known to be present in the SRM 1597a, 20 were tentatively identified based on retention times and the presence of 18 was confirmed based on excitation and emission spectral profiles.

Characteristics and Source Identification of Polycyclic Aromatic Hydrocarbons and n-Alkanes in PM2.5 in Xiamen

ABSTRACT PM2.5 samples were collected to characterize the organic compounds of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in Xiamen, China, in 2013. The concentrations of PM2.5, PAHs and n-alkanes were 55.53 µg m–3 and 22.14 µg m–3, 15.73 ± 6.25 ng m–3 and 5.65 ± 3.73 ng m–3, and 148.57 ± 36.84 ng m–3 and 97.53 ± 67.46 ng m–3 in winter and summer, respectively, demonstrating higher pollutant levels in wintertime. Benzo[e]pyrene (BeP) was the most abundant PAH, accounting for 32% and 26% of the total quantified PAHs in winter and summer, respectively, followed by coronene (Cor) and phenanthrene (Phe). 5-ring PAHs were the most dominant group, contributing 50.8% and 44.1% to the total quantified PAHs in winter and summer, respectively. Two peaks were exhibited by the homologue distributions of n-alkanes, and the dominant components were enriched in the high molecular weight fraction. Meteorological parameters had a stronger impact on the atmospheric PAH levels in summer than winter, and the most significant parameter was relative humidity (RH), followed by temperature. The diagnostic ratios indicated that PAHs in Xiamen were mainly contributed by petroleum combustion in the two seasons and the concentrations of n-alkanes were mainly influenced by anthropogenic sources. The annual values of the benzo[a]pyrene (BaP) equivalent concentration and incremental lifetime cancer risk (ILCR) were 0.83 ± 0.63 ng m–3 and 7.17 × 10–5 in winter and 1.11 × 10–4 ng m–3 and 3.29 × 10–5 in summer, respectively. The findings illustrated that the overall exposure risk to PM2.5-bound PAHs did not trigger an alert in Xiamen, but higher risks in winter were still shown to exist.

Identification and Quantification of Polycyclic Aromatic Hydrocarbons in Processed Chicken Meat Products

Identification and Quantification of Polycyclic Aromatic Hydrocarbons in Processed Chicken Meat Products

Identification of endogenous and anthropogenic hydrocarbons in bottom deposits of peat lakes and evaluation of their contribution to the “hydrocarbon index”

Gas chromatography with mass spectrometric detection was used to analyze bitumens isolated from bottom sediments of peat lakes contaminated with petroleum products. Endogenous hydrocarbons are characterized by the presence of n-alkanes with an odd number of carbon atoms in the molecule in the characteristic region of C23–C33, the absence of a “hump” characteristic of oil products in the chromatogram, and the presence of light hydrocarbons, eluting in the initial part of the chromatogram (light hydrocarbons are usually lost when the sample is dried). The distribution profile of odd n-alkanes is used to assess the contribution of endogenous hydrocarbons to the “hydrocarbon index” with the help of the pattern recognition method. The concentration of light hydrocarbons is from 50 and 300–400 to 3500–5000 mg/kg for a number of samples and even up to 26000 mg/kg in some samples. The concentration of petroleum hydrocarbons and heteroatomic compounds varies from the lowest values of 30–80 mg/kg up to 20000 mg/kg and higher.

Identification and Characterisation of Major Hydrocarbons in Thermally Degraded Low Density Polyethylene Films

The vast application of Low Density Polyethylene (LDPE) in packaging, greenhouses, homes etc has led to its huge accumulation as a municipal solid waste with monumental health, economic and environmental consequences. Since these are non-biodegradable and their photodegradation occurs only over a very long period, their economic conversion to energy products through pyrolysis is the thrust of this study. LDPE sample collected from the University of Ilorin Community was thermally degraded in a pyrolyser at temperatures ranging from 203 – 400 oC. The products of pyrolysis were in three (3) states of matter and both the liquid and solid products were analysed using FTIR to determine the functional groups and GC- MS for the hydrocarbons present in the products. For the GC-MS analysis, the peaks that had 90% above quality when compared with the compounds in the installed NIST11 library were reported. There were alkanes, alkenes, halogenated alkanes, and very few aromatics in the liquid product and, the hydrocarbons were observed to range between C10 - C27. The FTIR and GC-MS results show the potential of the oil obtained as renewable source of energy while that for residue shows its inherent energy content. The liquid product was refluxed over molecular sieve catalyst (US 2882244A) and the calorific value was found to increase from 13,974 kJ/kg to 15,815.52 kJ/kg and this is found to be comparable to the range for lignite and dry wood. Key words: environmental pollution, solid wastes, LDPE, pyrolysis, hydrocarbons, Calorific value.

Spatial distribution and sources identification of polycyclic aromatic hydrocarbons in Wolong Lake, Northeast China

The aquatic ecosystem maybe significantly affected by polycyclic aromatic hydrocarbons (PAHs) released from fresh water sediments. In order to protect biodiversity, the spatial distribution and sources of PAHs in the sediment of Wolong Lake in Northeast China were studied. A total of 17 surface sediment samples were collected and 12 PAHs were analyzed. The results were as follows. The concentration of total PAHs (TPAHs) ranged between 1412.9 μg/kg and 3948.3 μg/kg (dry weight). Indeno [1, 2, 3-c, d] pyrene was the dominant contaminant which accounted for 87%–98% of TPAHs. Diagnostic ratios of PAHs and principal component analysis showed that biomass combustion and vehicle emissions were likely to be the dominant sources of PAHs in the sediment. PAHs can be considered safe in the context of environmental and human health protection, based on the overall toxicity. Individual PAHs were positively correlated with total organic carbons. These results will be helpful to control PAHs and protect the aquatic ecosystem in the lake.

Contamination, source identification, and risk assessment of polycyclic aromatic hydrocarbons in agricultural soils around a typical coking plant in Shandong, China

ABSTRACTCoking is one of the most important emission sources of polycyclic aromatic hydrocarbons (PAHs) in China. Investigation of the contamination, distribution, and sources of PAHs in agricultural soils around Rong Xin coking plant, China, was conducted, and the potential human health risks were addressed. The total concentration of the 16 PAHs (∑16PAHs) on the United States Environmental Protection Agency priority list had a range from 1774 to 4621 µg/kg (mean 3016 µg/kg). Meanwhile, seven carcinogenic PAHs (∑PAH7c) owned the total concentrations of 684–2105 µg/kg, and they had the benzo[a]pyrene equivalent (BaPeq) concentrations at 139.616–1672.850 µg/kg. All soil samples were dominated by PAHs with two to four rings. Data analyses for the potential sources of PAHs showed that the PAHs in soils were principally from pyrogenic sources. Ecological risk assessment of soil PAHs showed that the BaPeq concentrations of ∑PAH7c accounted for 99% of the total ∑16PAHs, being a major carcinogenic contributors of ∑16PAHs. Higher levels of PAHs and higher total BaPeq concentrations in this study indicate a potential carcinogenic risk for humans. Therefore, long-term exposure to coking plants may increase the PAH concentrations in the environment and further raise a potential risk to human health.

Biological and analytical techniques used for detection of polyaromatic hydrocarbons.

Polycyclic aromatic hydrocarbons contain two or more fused benzene rings that are considered as cosmo-pollutants ubiquitously found in the environment. The identification and monitoring of polycyclic aromatic hydrocarbons (PAHs) are of great interests for rapid and on-site detection. Therefore, many analytical and biological techniques have been proposed for the qualitative and quantitative assessments of PAHs. Non-biological analytical techniques such as infrared, Raman, and fluorescence spectroscopies are commonly exploited as non-destructive techniques while gas chromatography (GC) and high-performance liquid chromatography (HPLC) with multiple detectors are extensively employed for the separation and detection of an analyte. Even though spectroscopy and chromatography are more accurate, convenient, and feasible techniques, often, these methods are expensive and sophisticated which require high maintenance cost. On the other hand, biological approaches, i.e., immunoassay, PCR, and microarray, offer comprehensive high-throughput specificity and sensitivity for a similar analyte. Biosensor- and immunoassay-mediated detections of PAHs have opened up new avenues in terms of low cost, rapid determination, and higher sensitivity. In this review, we have discussed the strengths and limitations of biological and analytical techniques that were explored for precise evaluation and were trusted at both the legislation and research levels.

Marine sedimentary lipidomics of the glacial-interglacial changes during the lower Pleistocene (SW Iberian Margin).

Analyses of trimethylsilyl-derivatized neutral lipids by gas chromatography coupled to mass spectrometry afford a wealth of information contained in the marine sediments. This information is useful for unraveling the processes associated with past climate changes such as those from glacial and interglacial periods. Studies of samples from the Iberian Margin deposited about 1,300,000-1,400,000years ago afforded the qualitative identification and quantification of n-alkanes, n-alkan-1-ols, isoprenoids, triterpenoids, sterols, hopanols, alkenones, alkenols, and polycyclic aromatic hydrocarbons. Using this information, the lipidomic approach has allowed to identifying differences in sea surface temperatures, marine productivity, microbial degradation processes, and inputs from continental plants between these periods. Differences in predominant higher plant species related to climate changes have also been observed.

Application of the SARA method for determination of hydrocarbons by GC/qMS in bio-oil obtained by fast pyrolysis of rice husk

This study presents the results of the use of fractionation preparative liquid chromatography (PLC) on columns of silica (based on the SARA method, traditionally used for oil samples).For characterization of bio-oils obtained by fast pyrolysis of rice husk. The method distributes compounds separating into four fractions, the majority polar compounds (F3 and F4) and hydrocarbons (F1 and F2). The fractions were analyzed by GC/MS allowing the identification and semi-quantitative determination of aliphatic hydrocarbons and HPAS. After the fractionation by PLC, only F1, F2 and F3 were possible to identify, a total of 180 compounds. The fractionation based on the SARA method, with modification, produced fractions (F1 and F2) free of polar compounds permitting the identification of aliphatic hydrocarbons and PAHs.