Polycyclic Aromatic Hydrocarbons Data Research Articles

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

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

Distribution, seasonal trends, and lung cancer risk of atmospheric polycyclic aromatic hydrocarbons in North China: A three-year case study in Dalian city.

Atmospheric monitoring data of polycyclic aromatic hydrocarbons (PAHs) over a three-year period were collected from an urban site in Dalian, northeast China. The status of PAHs in the atmosphere in Dalian were evaluated by assessing concentration levels, congener profiles, seasonal trends, primary source, inhalation exposure and the risk of developing lung cancer risk. Average concentrations were recorded for 53 PAHs (95±40ng/m3), 16 EPA priority PAHs (68±33ng/m3), 26 alkylated PAHs (17±7.6ng/m3) and 4 high-molecular-weight (302Da) PAHs (1.3±1.3ng/m3). Atmospheric PAH concentrations in winter were almost twice as high as those recorded in the summer, possibly due to enhanced local emissions and long-range transport of atmospheric PAHs during the winter. PAH congeners were dominated by phenatherene, fluoranthene, pyrene and fluorene, accounting for 46.0% of total ∑53PAH concentrations. Ship/vehicle emission and mixed combustion were identified as the main sources of PAHs using diagnostic PAH concentration ratios and principal component analysis-multiple linear regression. Benzo(a)pyrene toxicity equivalent concentration had an average content of 32±37 ng/m-3 over the sampling period, with dibenzo(a,h)anthracene (50.7%) and dibenzo(a,l)pyrene (26.4%) being the largest contributors. The risk of developing lung cancer due to inhalation exposure to outdoor PAHs was calculated at 12.0‰ using the overall population attributable fraction (PAF). Our results estimate that, due to PAH exposure in Dalian, the average excess lung cancer risk during a person's lifetime is 35.7 cancer cases per one million inhabitants.

Water-Sediment Partition of Polycyclic Aromatic Hydrocarbons (PAHs) in Nansi Lake

Based on field data of polycyclic aromatic hydrocarbons (PAHs) in water and sediment in Nansi Lake. The concentrations and the partitioning characteristic of PAHs in the water and sediment were studied. The lgKd of high molecular weight PAHs were higher than the low molecular weight PAHs. The most of PAHs Kd values were negligible correlated with TOC, soluble salt, clay and pH of the sediment in Nansi Lake.

The ecosystem baseline for particle flux in the Northern Gulf of Mexico

Response management and damage assessment during and after environmental disasters such as the Deepwater Horizon (DWH) oil spill require an ecological baseline and a solid understanding of the main drivers of the ecosystem. During the DWH event, a large fraction of the spilled oil was transported to depth via sinking marine snow, a routing of spilled oil unexpected to emergency response planners. Because baseline knowledge of particle export in the Northern Gulf of Mexico and how it varies spatially and temporally was limited, we conducted a detailed assessment of the potential drivers of deep (~1400 m depth) particle fluxes during 2012–2016 using sediment traps at three contrasting sites in the Northern Gulf of Mexico: near the DWH site, at an active natural oil seep site, and at a site considered typical for background conditions. The DWH site, located ~70 km from the Mississippi River Delta, showed flux patterns that were strongly linked to the Mississippi nitrogen discharge and an annual subsequent surface bloom. Fluxes carried clear signals of combustion products, which likely originated from pyrogenic sources that were transported offshore via the Mississippi plume. The seep and reference sites were more strongly influenced by the open Gulf of Mexico, did not show a clear seasonal flux pattern, and their overall sedimentation rates were lower than those at the DWH site. At the seep site, based on polycyclic aromatic hydrocarbon data, we observed indications of three different pathways for “natural” oiled-snow sedimentation: scavenging by sinking particles at depth, weathering at the surface before incorporation into sinking particles, and entry into the food web and subsequent sinking in form of detritus. Overall, sedimentation rates at the three sites were markedly different in quality and quantity owing to varying degrees of riverine and oceanic influences, including natural seepage and contamination by combustion products.

An approach to uncertainty estimation in determining polycyclic aromatic hydrocarbons in fuel-contaminated soils

An estimation of uncertainty contribution in the entire set of the analytical data of polycyclic aromatic hydrocarbons (PAHs) in soil during a full year is presented. The analyses were performed as part of a project devoted to the assessment of the natural attenuation of selected PAHs in agricultural soil contaminated by a fuel spill. In particular, we investigated the effect of natural attenuation on the PAH dissipation rate in plots of two types of scenarios in agricultural soils. One of them was previously affected by an accidental fuel spill 10 years ago, and the other one was non-affected. The major components for estimating uncertainty contributions have been evaluated based on intermediate precision from different levels of PAH mass fraction, sample locations, and long term data set. An analysis of variance (ANOVA) test was applied to the mass fractions of clean or blank soil sub-samples versus contaminated soil sub-samples for grouping comparable data. Variables of influence in this study were site, month, and lysimeter of sampling (referring to a stainless steel box, with side lengths of 50 cm). Study sites or the spatial arrangement of lysimeter showed a clear effect in sub-sample results with the lowest mass fraction levels for heavier PAH, while monthly sampling was the variable of most significant influence for the more strongly contaminated sub-sample results. Finally, the results of the PAH mass fractions in contaminated soil sub-samples indicated a monthly variation for which lighter, volatile PAHs rapidly decreased while the less volatile did not change.

Source and significance of selected polycyclic aromatic hydrocarbons in sediments (Hovea-3 well, Perth Basin, Western Australia) spanning the Permian–Triassic boundary

Stable carbon isotopic data for polycyclic aromatic hydrocarbons (PAHs; chrysene and triphenylene, benzo( e)pyrene, 9-methylphenanthrene) in sediments of comparable thermal maturity from a petroleum drill core (Hovea-3 well, Perth Basin, Western Australia) spanning the largest mass extinction event in the past 500 million years (Permian–Triassic boundary) are consistent with an algal kerogen source in the basal Triassic as opposed to a combustion and/or higher-plant source in the underlying Permian sediments. The δ 13C values of extractable PAHs are less negative in the Permian inertinitic interval (−24.7‰ to −29.2‰) than the Triassic sapropelic interval (−30‰ to −33.3‰). A strong correlation is evident between δ 13C of individual PAHs, δ 13C of kerogen and Rock-Eval pyrolysis hydrogen index providing unequivocal evidence that PAH δ 13C is mainly controlled by organic matter type. Abundant algal-derived PAHs in basal Triassic sediments may be a global feature; the lack of coal globally in the basal Triassic sediments is also consistent with this observation. The Early Triassic coal gap appears to coincide with the global extinction of peat-forming plants at the end of the Permian, coal did not reappear until the Middle Triassic and Permian levels of plant diversity and thick peat deposits did not recover until the Late Triassic. The PAH isotopic data support the contention that a global anoxic event at the end of the Permian period contributed to the gradual worldwide asphyxiation and ultimate extinction of many marine and terrigenous organisms.

Correlation between hydrophobic and molecular shape descriptors and retention data of polycyclic aromatic hydrocarbons in reversed-phase chromatography on non-liquid-crystalline, nematic, and smetic stationary phases

The local anisotropic ordering of side-chain liquid-crystalline polymer (SCLCP) stationary phases has been revealed statistically. For this purpose the RP HPLC separation of polycyclic aromatic hydrocarbons (PAH) on silica coated with three classes (non-liquid-crystalline, nematic, and smectic) of side-chain polymer (SCP) has been compared. The logarithm of the capacity factor (logk) was correlated with three PAH descriptors-the connectivity index (χ) or the hydrophobic fragmental constant (logP), the length-to-breadth ratio (L/B), and a non-planarity term (Np). Statistical results revealed good correlation between the model and experimental data, enabling the different stationary phases to be compared. Recognition of solute size seems similar for each class of polymer but solute non-planarity recognition grows continuously as ordering of the liquid-crystal polymer increases. Recognition of solute lengthening is non-existent for non-liquid-crystalline polymers and suddenly, appears with liquid crystalline polymers. Shape recognition is better for smectic than for nematic SCP. The predictive, ability of this model was tested on highly condensed aromatic compounds. The connectivity index, χ, did not seem appropriate for such systems. its replacement by Rekker's hydrophobic, fragmental constant, logP, was necessary for fitting the retention of these solutes on liquid-crystalline stationary phases.

High-sensitivity chromatographic detector incorporating three-dimensional charge coupled device fluorimetry

This article describes a detector for liquid chromatography that provides three-dimensional, excitation–emission-intensity data of fluorescent compounds. The instrument achieves multi-wavelength excitation by employing a polychromator that disperses radiation along the vertical portion of a quartz capillary flow cell. The ensuing sample fluorescence is collected in the horizontal plane and dispersed using an emission polychromator to form a focused two-dimensional excitation–emission image at a charge coupled device (CCD) pixel array. Each vertical pixel equates to a narrowly defined excitation wavelength band, whilst horizontal pixels equate to corresponding emission wavelengths, with the intensity of light encroaching onto the CCD pixel elements providing the third-dimensional variable in the measurement. It is shown that the extreme sensitivity of CCD detection coupled to the dual polychromator arrangement makes possible the collection of fluorescence excitation–emission-intensity data of polycyclic aromatic hydrocarbons in a flow stream in less than 0.05 s with nanogram per millilitre limits of detection.

Retention system, thermodynamic properties and structure correlations of environmental analytes

A composite chromatographic retention index system has been developed for identifying polycyclic aromatic hydrocarbons, polychlorinated biphenyls and polychlorinated pesticides. When retention indices and thermodynamic data of polycyclic aromatic hydrocarbons on 5% phenylmethylsiloxane stationary phase were compared with those obtained on polydimethylsiloxane a correlation was found between retention and electronic properties. Determination and quantitation of individual contaminants in water and sediment samples from Lake Mecoacan were achieved by capillary gas chromatography with flame ionization and electrocapture detection.

A critical evaluation of two proposed atmospheric partitioning mechanisms, Adsorption and absorption, using atmospheric data for polycyclic aromatic hydrocarbons.

A critical evaluation of two proposed atmospheric partitioning mechanisms, Adsorption and absorption, using atmospheric data for polycyclic aromatic hydrocarbons.

Correlations between gas chromatographic retention data of polycyclic aromatic hydrocarbons and several molecular descriptors

Statistical and factor analysis have been used to test the ability of several molecular descriptors to predict the retention indexes (I) of polycyclic aromatic hydrocarbons determined on SPB-5 and SPB-20 stationary phases. Regression analysis with both columns showed that linear regression with connectivity index and bending energy of the molecules as independent variables gave the best correlation coefficients. ΔI20–5, considered to be a measure of the polar forces in retention, gave a good correlation with the van der Waals radii of the molecules, or strain, and bending energy.

NCI/MRI Chemical Carcinogen Reference Standard Repository

Abstract The National Cancer Institute repository was established nearly 18 years ago to provide a centralized source of well-characterized standards for distribution to the carcinogenesis research community. The NCI repository at Midwest Research Institute consists of over 800 chemicals. During the last fiscal year, 237 orders for characterized standards, consisting of 837 aliquots of 82 chemicals, were received; 185 orders were from organizations within the United States and 52 were from foreign countries. A total of 412 aliquots of polycyclic aromatic hydrocarbon (PAH) metabolites were shipped, making this the most requested class of chemicals in the repository. The average turnaround time during the last fiscal year, from receipt of an order until shipment of the material, was 5 days. A publication, “Handbook of Analytical and Spectral Data for Polycyclic Aromatic Hydrocarbons, Volume I, Benzo[a]pyrenes and its Metabolites”, is available through the repository.

Correlations between retention data of polycyclic aromatic hydrocarbons in micellar liquid chromatography and several molecular descriptors

Statistical and principal component analysis have been used to establish some general equations relating retention parameters to molecular descriptors of polycyclic aromatic hydrocarbons. They allow the determination of the retention behaviour of a solute in micellar liquid chromatography using lauryl sulphate, hexadecyltrimethyl-ammonium bromide and polyoxyethylene (23) lauryl ether (Brij-35) micellar systems and a Novapack C18 column.

Retention of hydrophobic solutes on reversed-phase liquid chromatography supports: Correlation with solute topology and hydrophobicity indices

Retention of several nonpolar solutes on two reversed-phase liquid chromatography (RPLC) supports was examined during isocratic, isothermal elution with binary mixtures of methanol/water and acetonitrile/water. Changes in chromatographic retention factors (k) were correlated with the following indices of solute hydrophobicity and molecular topology: octanol-water partition coefficient (K ow), hydrophobic surface area (HSA), and first-order molecular connectivity ( 1 χ). For each sorbent-solvent combination, one regression equation was required to describe the data for polycyclic aromatic hydrocarbons and halobenzenes, and another for the alkylbenzenes. This distinctive behavior was attributed to the differences in the nature of the interaction of these two groups of solutes with the bonded, n-alkyl chains. Solute molecular size, shape, and conformation as well as hydrophobicity appear to be the dominant factors controlling solute retention by RPLC supports.

Correlation between retention data of polycyclic aromatic hydrocarbons and several descriptors in supercritical-fluid chromatography

The correlation between retention data of polycyclic aromatic hydrocarbons (PAHs) obtained in various supercritical fluid-chromatographic systems (SFC systems) and several descriptors is investigated in order to determine the dominant factors controlling the retention. It is clear that the separation of PAHs in SFC is primarily controlled by the molecular size of the solute and its polarizability. The retention in SFC can be predicted with help of the equation derived by this study.

Correlation between the retention data of polycyclic aromatic hydrocarbons and several descriptors in reversed-phase-HPLC

The separation of polycyclic aromatic hydrocarbons (PAH) on various reversed-phase columns (phenyl, ethyl, octyl and octadecyl) have been compared. The correlations between the logarithm of capacity factor (log k′) and several descriptors, which show the molecular size, shape and physical property of a solute, were determined. The results indicated the high possibility to predict the retention of PAH in reversed-phase high performance liquid chromatography.

Correlation between the retention data of polycyclic aromatic hydrocarbons and several descriptors in reversed-phase HPLC

The separation of polycyclic aromatic hydrocarbons (PAH) on various reversed-phase columns (phenyl, ethyl, octyl and octadecyl) have been compared. The correlations between the logarithm of capacity factor (log k′) and several descriptors, which show the molecular size, shape and physical property of a solute, were determined. The results indicated the high possibility to predict the retention of PAH in reversed-phase high performance liquid chromatography.