Concentrations Of Individual Polycyclic Aromatic Hydrocarbons Research Articles

Effects of Chinese “double carbon strategy” on soil polycyclic aromatic hydrocarbons pollution

Polycyclic aromatic hydrocarbons (PAHs) and carbon dioxide primarily originate from the combustion of fossil fuels and biomass. The implementation of the Chinese “double carbon strategy” is expected to impact the distribution of PAH emissions, consequently influencing the spatial distribution trend of PAHs in surface soil. Therefore, it is crucial to quantitatively evaluate the effectiveness of the Chinese “double carbon strategy” on soil PAH pollution for the purpose of “the reduction of pollution and carbon emissions”. This study utilized 15,088 individual PAH concentration data from 943 soil samples collected between 2003 and 2020 in China, in conjunction with PAH emissions at a 10 km resolution, for meta-analysis. The calculated PAH emissions in this study are in line with the global PAH emission inventory (PKU-PAH-2007), with a relative standard deviation at the provincial level of less than 25 %. Subsequently, a novel method was developed using emission density and Kow of PAHs to predict PAH concentrations in surface soil based on a least-squares regression model. Compared to other environmental models, the method established in this study significantly reduced the percent sample deviation to less than 70 %. Furthermore, energy consumption data for China were simulated based on the implementation plan of the “double carbon strategy” to project PAH emissions and soil PAH levels for the years 2030 and 2060. The predicted PAH emissions in China were estimated to decrease to 41,300 t in 2030 and 10,406.5 t in 2060 from 78,815 t in 2020. Moreover, the heavily contaminated areas of soil PAHs (i.e., total PAH concentrations in soil exceeding 1000 μg kg−1) were projected to decrease by 45 % and 82 % in 2030 and 2060, respectively, compared to levels in 2020. These findings suggest that the implementation of the “double carbon strategy” can fundamentally reduce the pollution of PAHs in surface soil of China.

Characterization of polycyclic aromatic hydrocarbons in mangrove sediments from Ifiekporo Creek, Warri, Nigeria

The occurrence and level of polycyclic aromatic hydrocarbons (PAHs) in mangrove sediment from Ifiekporo Creek in Warri, Delta State, Nigeria, were assessed in this study. The extraction of PAHs from the sediment samples was achieved using the PAH analytical test method (USEPA 8270). This method measures the individual concentrations of extractable PAHs in samples. The PAHs were quantified within the C11-C22 subgroup. The basic GC parameters for the analysis of polyaromatic hydrocarbons were analysed using a gas chromatography‒mass selective detector (GC‒MSD). The individual PAH concentrations in the mangrove sediment samples ranged from 850 µg/kg−1 to 3470 µg/kg−1. PAH source apportionment employing isomeric ratios and multivariate statistics indicated both pyrogenic and petrogenic source inputs in the sediment samples. The order of PAH homology in the sediment was 3-ring > 2-ring > 4-ring. The sediment samples were mostly dominated by LMW PAHs. The results of the ecological risk assessment in the study area indicate that there is low ecological risk associated with PAH exposure in sediment. These results provide data on the concentrations and compositional patterns of PAHs, which is useful for understanding the effects, sources, fates, and transport of PAHs in sediment in the study area, as well as for providing relevant information for environmental quality management and forensic studies.

Spatial distribution and partition of polycyclic aromatic hydrocarbons (PAHs) in the water and sediment of the southern Bohai Sea: Yellow River and PAH property influences

The marginal Bohai Sea, connected to the northwestern Pacific Ocean, is threatened by human activity. The Yellow River, the second largest river in China, drains large amounts of water, silts, and polycyclic aromatic hydrocarbons (PAHs) into the southern Bohai Sea; however, to what extent the Yellow River inputs influence the spatial distributions and partitions of PAHs in the southern Bohai Sea is not well known. Therefore, this study collected surface water, bottom water, and sediment samples from the southern Bohai Sea and analyzed them to examine the spatial distributions and partitions of 15 priority PAHs. The results showed that PAH concentrations ranged from 26.9 to 50.1 ng L–1 in surface water, 18.8 to 44.1 ng L–1 in bottom water, and 7.4 to 143.9 ng g–1 in sediment, with higher proportions of four-, five-, and six-ring PAHs in sediment than in water. PAH inputs from the Yellow River and sea coastal currents determined the spatial distribution of PAH concentrations in water and sediment, with an overall decrease from the estuary to the southeast. However, the solid dilution effect of input silts from the Yellow River and the liquid dilution effect of water from the Yellow River and Yellow Sea led to lower PAH concentrations in the water and sediment of the southern Bohai Sea than those in other areas of the Bohai Sea. PAH exchange between the atmosphere and seawater led to significantly higher individual PAH concentrations (except for acenaphthylene) in the surface water than in the bottom water, with ratios significantly related to the PAH n-octanol-water partition coefficient, organic carbon-water partition coefficient, and Henry's law constants. These parameters also determined PAH partitioning between the bottom water and sediment. Individual and total PAH concentrations in the sediment were significantly correlated with organic matter, clay, and silt contents. Therefore, the partitions and spatial distributions of PAHs in the southern Bohai Sea comprehensively depend on PAH properties, PAH inputs from the Yellow River and the atmosphere, sea currents, and seawater and sediment properties. The ecological risks posed by individual PAHs in both water and sediment were negligible or acceptable.

Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Seafood from Orashi River in Omoku, Rivers State of Nigeria and Human Health Risk Assessment

This study investigated the level of polycyclic aromatic hydrocarbons (PAHs) in seafood, namely, C. sapidus (Crab), P. mollusca (Mollusc), Cambarus sp. (Crayfish), Caridea (Shrimp) from Orashi River in Omoku, Rivers State of Nigeria. The PAHs in the samples were determined by gas chromatography–mass spectrometry. There was no variation in the relative level of PAHs congeners. The mean concentrations of individual PAHs decreased in the order: D(a,h)ant > Pyr > Fluth > B(g,h,i)p > B(a)A > B(b)f > Ind (1,2, 3)pyr > B(a)pyr > Chr > B(k)flu > Ant > Flu > Phen > Aceth > Ace > Nap. Anthracene contributed the highest PAHs values, with 51.685% in Caridea. The EDI values of B(a)P, Ʃ2PAH, Ʃ4PAH, Ʃ8PAH across all the seafood were within the maximum permissible limit recommended by EFSA; this suggests that the accumulation of the PAHs in the body system are within the permitted levels. Similarly, the HI of the PAHs congeners obtained from this study were less than 1 which is the safe limit recommended by USEPA. The total Excess Cancer Risk of the PAHs congeners obtained from this study exceeded the permissible maximum limit recommended by USEPA. This study suggests that the water may be contaminated with PAHs which have the tendency to cause non-carcinogenic and carcinogenic risk because of frequent and high consumption of seafoods.

Modeling environmental sensitivity and risk assessment of PAHs in sediments along two marine coastal areas in Egypt

Modeling the environmental sensitivity index (ESI) is vital in the planning and management processes, especially along the coastal areas. The main objectives of the study were to define the main sources of polycyclic aromatic hydrocarbons (PAHs), establish an ESI model, and measure the risk of PAHs on humans and the environment using various equations. The methodology of the research involved analyzing PAHs according to the EPA 550 methodology in sediments of the coastline in two important coastline areas in Egypt, namely the Gulf of Suez and the Mediterranean Sea, modeling the sensitivity of PAHs using ArcGIS 10.5 by integrating different physical, biological, and land use/cover factors, identifying the sources, and performing a risk assessment. Nine sediment samples were collected from each area. The produced sensitivity map could explain the highly sensitive areas along the Mediterranean Sea and Gulf of Suez coastlines (especially areas that were near drains' outlets, industrial sites, and sea ports). The highest mean PAH concentrations were Acenaphthylene and Fluorine in the Mediterranean Sea and Suez Gulf, respectively. It's obvious that the individual PAH concentrations were within the ERL, ERM, and PEL threshold limits, indicating no adverse biological impacts. The ratios of BaA/BaA + Chy, Flu/Flu + Py, and Ant/Ant + Phe gave an indication that most PAH sources were petrogenic (63.64%) and others (36.36%) were from petroleum combustion. The principle component analysis (PCA) indicated a diverse correlation among the isomer ratios and LU/LC activities. The carcinogenic risk values were in the very low category (<10−6) for both children and adults. The most significant contributors to carcinogenicity were IP and BkFlu in the Mediterranean Sea and Suez Gulf, respectively. Increasing sources of carbon in seawater, especially with climatic change, may impact the aquatic environment and have impacts on organisms and coral reefs. So it is highly recommended to keep shorelines and seawater free of oil spillage activities along the coastal areas or take actions towards this.

Risk assessment of sediment PAH, BTEX, and emerging contaminants in Chanomi Creek Niger Delta, Nigeria.

This study assessed the levels of polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, and xylene (BTEX), and emerging contaminants in Chanomi Creek. Sediment samples were collected between March 2019 and July 2020 to evaluate the concentrations of PAH, BTEX, and emerging contaminants using GC-MS and GC-FID with Headspace extraction. Results indicated mean PAH concentrations were 22.691 ± 15.09µg/kg. The highest individual PAH concentrations were fluorene (7.085µg/kg), naphthalene (4.517µg/kg), and phenanthrene (3.081µg/kg). Carbazole (0.828µg/kg) was discovered as a novel environmental toxin with dioxin-like toxicity and widespread prevalence in sediments. The most common congener (25%) was ethylbenzene, followed by toluene and ortho- and meta-xylene (21%) and benzene (13%). The analysis of diagnostic ratios revealed that the main factors responsible for the presence of PAHs in the study area are the residential use of firewood, emissions from industrial activities, bush burning, and petroleum slicks. The risk assessment indicated that most PAHs exceeded the permissible risk quotient values, suggesting a moderate to high ecological risk. However, cutaneous exposure to PAHs and BTEX was found to have minimal impact on human health, with no significant hazards identified in adults and children. Nevertheless, the study revealed low cancer risks associated with PAH and BTEX compounds for both age groups. The continued discharge of PAHs and BTEX compounds into Chanomi Creek could have significant long-term negative effects on human and aquatic health. Thus, contamination risk awareness programs and the development of stringent contextual thresholds for identified contaminants could enhance environmental and public health protection.

Spatiotemporal variability and measurement uncertainty in atmospheric polycyclic aromatic hydrocarbons (PAHs): A quantitative variance component analysis

A comprehensive understanding of the spatial and temporal variability in air pollution facilitates air monitoring designs, exposure assessment, and environmental epidemiology research. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the air but are challenging to measure due to their low concentrations. To date, no study has been specifically designed to quantify the spatial and temporal aspects of variability in ambient PAH concentrations. This study aims to decompose the variability in PAH concentrations measured in the ambient air in a metropolitan area into different components. Air samples were collected using high-volume samplers at 19 stations in the Memphis Tri-state Area across Tennessee, Arkansas, and Mississippi, USA, every 12 days from March 2018 to May 2019. Samples were collected on polyurethane forms and quartz fiber filters and analyzed using gas chromatography/mass spectrometry (GC/MS) for 32 PAHs. Variance components of the total variance were computed using mixed models for individual PAHs and sum concentrations of the 16 priority PAHs (Σ16PAHs). For Σ16PAHs, spatial and temporal variability represented 16% and 84% of the total variance. The total variance could be further apportioned to between-urbanicity (0.5%), between-site (5.5%), between-season (41%), and within-season (53%) variances. Sampling and analytical uncertainties represented 39% and 0.01% of the total variance, when monitoring uncertainties were considered. Concentrations of individual PAHs followed similar variance structures. These findings confirmed the validity of centralized monitoring stations to represent a large area, suggested the need for repeated samples across seasons and at multiple time points within a season, and warranted improving quality control for field sample collections.

Rapid bioanalytical screening for the assessment of internalized exposure to Polycyclic Aromatic Hydrocarbons in clinical samples of Florida Firefighters

BACKGROUND AND AIM: Polycyclic aromatic hydrocarbons (PAHs) are toxic byproducts of combustion and ubiquitous environmental pollutants which can cause carcinogenesis. Firefighters are routinely exposed to these contaminants and numerous studies have described a high incidence of various cancer types in firefighters compared to the general population. Our aim was to develop a streamlined process that allows accurate quantitative evaluation of PAH exposure in clinical samples collected from Florida Firefighters. METHODS: Urine samples were collected from twenty-five (25) active firefighters stationed in Florida at the beginning and end of a 24-hour shift, and twenty-one (21) new recruits after the completion of different fire trainings. We developed a rapid, non-invasive method to assess their internalized exposure to PAHs as part of the Firefighter Cancer Initiative (FCI). The use of automated extraction systems and Gas Chromatography – Mass Spectrometry enabled the accurate, qualitative, and quantitative detection of PAHs identified as priority pollutants by the United States Environmental Protection Agency. RESULTS: Total PAH exposure levels of the 25 active firefighters were significantly higher after the completion of the 24-hour shift, with those that answered fire-related calls, rather than EMS calls, exhibiting the highest concentrations of individual and gross PAHs. Similarly, total internalized exposure was increased in firefighter trainees compared to controls. We observed that participation in a Class B fire training, which involves flammable liquid materials, is associated with higher exposure to PAHs compared to participation in Class A exercises that employ ordinary combustible materials. CONCLUSIONS: Our findings showcase the unsafe levels of carcinogen exposure faced routinely by firefighters, highlighting the need for further investigation of the link between occupational exposure and health-related effects. The novel biomonitoring tool we developed facilitates large-scale screening of clinical samples and can be used for real-time assessment of carcinogen exposure. KEYWORDS: PAHs, exposure assessment, firefighters, biomonitoring, occupational exposure

Baseline occurrence, distribution and sources of PAHs, TPH, and OCPs in surface sediments in Gorgan Bay, Iran

Baseline polycyclic aromatic hydrocarbons (PAHs), total petroleum hydrocarbons (TPH) and organochlorine pesticides (OCPs) in surface sediments were measured in Gorgan Bay, Iran. Total PAHs, TPH, and OCPs concentrations ranged between 13.70 and 23.68 ng g−1, 2.97 to 11.51 μg g−1 dry weight, and below detection to 1.41 ng g−1, respectively. Benzo [k] fluoranthene and anthracene had the highest (BkF; 19.77 ± 0.08 ng g−1), and lowest (Ant; 4.38 ± 1.72 ng g−1) individual PAH concentrations, respectively. The most abundant OCPs were β-Endosulfan, followed by methoxychlor and endrin. PAH isomeric ratios in sediments revealed that contamination originated from mixed sources, with a strong indication of pyrogenic sources. Ecological risk assessments based on sediment quality guidelines (SQGs) suggested that individual PAHs and OCPs posed low ecological risks in Gorgan Bay.

Microplastics contributed much less than organic matter to the burial of polycyclic aromatic hydrocarbons by sediments in the past decades: a case study from an urban lake.

The role of microplastics in burying hydrophobic organic compounds remains largely unknown. Sediment cores collected from the center of a typical urban lake (Lake Qianhu) in China were chosen to explore the contribution of microplastics to the burial of polycyclic aromatic hydrocarbons (PAHs) by sediments, and to elucidate how this contribution changed with microplastic composition and the hydrophobicity of PAHs on a decade scale. Our results showed that the concentration of individual PAHs adsorbed by microplastics varied from detection limit (LOD) to 7.2 mg g-1 MP, which was much higher than the LOD to 31.0 μg g-1 TOC buried by total organic carbon. However, the amount of individual PAHs adsorbed by microplastics only contributed to 0-34.2% of that in sediments. Changes in the composition of microplastics, including the increased proportion of polyethylene and polypropylene : polyethylene polymer in sediments, resulted in the average microplastic sediment burial ratios (MSBRs) of most PAHs increasing by 0.13% to 2.7% in the period from 1997 to 2018 compared with those in the period from 1975 to 1996. The average MSBRs varied with the hydrophobicity of PAHs, which increased with log Kow value if it varied from 3.45 to 5.20, but decreased with log Kow if it was in the range of 5.30 to 6.50. Our study provides novel knowledge on the contribution of microplastics to the burial of PAHs by sediments.

Octanol-water partition coefficient (logKow) dependent movement and time lagging of polycyclic aromatic hydrocarbons (PAHs) from emission sources to lake sediments: A case study of Taihu Lake, China

Understanding the movement of polycyclic aromatic hydrocarbons (PAHs) from emission sources to sediments is important for achieving long-term pollution control of PAHs in sediments. In this study, by exploring the correlation of individual PAHs concentrations (CPAHs) in Taihu Lake sediments reported in the past twenty years with their annual emissions (EPAHs) in the lake region, it was observed that mean concentrations of PAHs with low logKow (i.e., logKow≤4.00) in Taihu Lake sediments were correlated best with their emissions without lagging between the sediment sampling time and the PAHs emitting time. However, for PAHs with middle logKow (i.e., 4.00<logKow≤4.57) or high logKow (i.e., logKow>4.57), their mean concentrations in sediments were correlated best with the emissions of PAHs emitted 1 or 2 years before the sediment sampling time. The longer lagging time of PAHs with middle or high logKow from emission sources to lake sediments could be attributed to their retardation in soils and river sediments around the lake. Moreover, the retardation in soils and river sediments is dependent on PAHs logKow and degradation half-life, indicating the dependence of PAHs concentration in sediments on their environmental behaviors, including sorption and degradation. Kow dependent movement and the time lagging observed in Taihu Lake for PAHs from emission sources to sediments could be valuable for developing measures to control PAHs, especially for congeners with high logKow.

Levels and Compositions of Polycyclic Aromatic Hydrocarbons in Rainwater and Their Implication for Aquatic Environments in Urban Area in Saitama, Japan

In this study, we investigated concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) in rainwater and surface water samples collected in Saitama, an urban city located in Japan. The volume-weighted mean concentration of total PAHs in rainwater samples (dissolved + particulate) was 108.8 ng L−1 with a range of 17.6–192.9 ng L−1. Two and three benzene ring PAHs were predominantly detected, occupying 67.0% of the total concentration in rainwater samples. Individual PAH concentrations were negatively correlated with their K ow, suggesting that low-molecular-weight PAHs are preferentially scavenged owing to the higher hydrophilicity. The toxic equivalent calculated based on the relative potencies of individual PAHs showed high toxic contributions by chrysene and benz[a]anthracene in the rainwater samples. Those PAHs levels in rainwater were comparable or higher than those in adjacent river water. Correlation coefficient of PAH signatures between rainwater and surface water samples was high particularly in the dissolved phase, supporting the source/sink relationships of PAHs between wet deposition samples and receiving waters. The mean deposition flux of PAHs was 2000 ng m−2 and considered to increase with precipitation amounts.

Oral and Dermal Bioavailability Studies of Polycyclic Aromatic Hydrocarbons from Soils Containing Weathered Fragments of Clay Shooting Targets.

The relative oral bioavailability and dermal absorption of chemical substances from environmental media are key factors that are needed to accurately estimate site-specific risks and manage human exposures. This study evaluated the in vivo relative oral bioavailability and in vitro dermal absorption of several polycyclic aromatic hydrocarbons (PAHs) found in soils collected from two formerly used Department of Defense sites impacted by weathered fragments of clay shooting targets. Concentrations of individual carcinogenic PAHs in the ≤250 μm fraction of soil ranged from approximately 0.1 to 100 mg/kg. A novel sample preparation method was developed to produce accurate and precise test diets for oral studies. The resulting test diets showed consistent concentrations of PAHs in soil- and soil-extract-amended diets and a consistent PAH concentration profile. Mean oral relative bioavailability factors (RBAFs) and dermal absorption fractions (ABSd) for benzo(a)pyrene ranged from 8 to 14% and 0.58 to 1.3%, respectively. Using the RBAF and ABSd values, measured here, for benzo(a)pyrene in USEPA's regional screening level equations yields concentrations for residential soils that are approximately eight times higher than those when default values are used (e.g., 9.6 vs 1.2 mg/kg at a target excess risk of 1 × 10-5).

Phase distribution and risk assessment of PAHs in ambient air of Hamadan, Iran

In the present study, both gaseous and particulate (PM with dae <2.5 µm) phases of polycyclic aromatic hydrocarbons (PAHs) were measured in the ambient air of Hamadan city, Iran. For this reason, two low-volume samplers equipped with glass fiber filters were used for sampling of particulate phase (N = 30) and XAD-2 sorbent tubes were applied for sampling gaseous phase of PAHs (N = 30). The sampling was conducted during warm and cold seasons in 2019. The average of cold/warm season ratios for Σ16PAH and PM concentrations were 1.14 and 0.62, respectively. Summed PAHs concentration were determined to be in the range 0.008–59.46 (mean: 11.61) ng/m3 and 0.05–40.83 (mean: 10.22) ng/m3 for the cold and warm seasons, respectively. A negative Pearson correlation coefficient was obtained for wind speed and relative humidity. The average Benzo (a) Pyrene equivalent carcinogenic (BaPeq) levels in the cold season were lower than the maximum permissible risk level of 1 ng/m3 for BaP. The BaP toxicity equivalency (ΣBaPTEQ) and BaP mutagenicity equivalency (ΣBaPMEQ) appeared to be significantly higher in the cold season (averaging 0.35 and 1.65 ng/m3, respectively) than those in warm season. Health risk assessment was performed for children and adults based on BaPeq, inhalation cancer risk. The diagnostic ratios of individual PAHs concentration showed that the significant sources of PAH emissions may be related to light duty vehicles (LDVs) in Hamadan. Although, some other sources such as pyrogenic source and petrol combustion were also suggested.

Spatial, temporal, and inter-compartmental environmental monitoring of lipophilic pollutants by virtual organisms

Sampling points belonging to the Harz National Park river system, Germany, were selected between the period of 2014 and 2017 for monitoring polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in water, air, and sediment. Triolein-containing Virtual Organisms (VO) were employed to assess the levels of chemicals in water, air and triolein as surrogate for natural fat. To avoid overestimation of the concentrations 20 performance reference compounds (PRCs)-16 PRCs-PAHs and 4 PRCs-PCBs were covering the range of properties of native compounds. Results manifested the highest concentration of individual PAH as follows: 31 ng fluoranthene/L water, 3600 ng pyrene/g fat, 62 ng phenanthrene/m3 air and 2800 ng fluoranthene/g dw sediment. All PCBs and OCPs values were below above mentioned PAH concentrations and far below EU-limit levels. Environmental partition of chemicals was investigated by calculating fugacity, suggesting a mass transport from water to air. Only quite volatile compounds such as hexachlorobutadiene showed higher fugacity in air. Ratios of sediment/water concentrations and log Kow within individual sampling periods at Holtemme River exhibited strong linear relationships. Interestingly, during summer months of the years water and fat contents well correlate to the flow rates of Holtemme River. Our results show that VO can be successfully used as a tool for ongoing exposure assessment studies and predictions of worst case levels in food and nutrition.

Bisphenol A (BPA) and polycyclic aromatic hydrocarbons (PAHs) in the surface sediment and bivalves from Hormozgan Province coastline in the Northern Persian Gulf: A focus on source apportionment

This study investigates Polycyclic Aromatic Hydrocarbons (PAHs) and Bisphenol-A (BPA) pollution in coastal sediments and bivalves of Hormozgan Province coastline. The results indicated that the BPA concentration in some bivalves reached up to 340.16 ng g−1. The mean BPA concentration in the sediment samples was also 787.01 ng g−1. The ∑PAHs content in sediments ranged from 14.54 to 85.00 ng g−1, while values for bivalves ranged from 5.37 to 16.40 ng g−1. Individual PAH concentrations in sediments exceeded those in bivalves for which only LMW PAHs were detected. A combination of techniques including Self-Organizing Maps (SOM), Positive Matrix Factorization (PMF), and Cluster Analysis (CA) were applied and both petrogenic and pyrogenic sources were identified. The risk of PAHs in the sediments was relatively low according to the sediment quality guidelines. The health risk indices suggest that exposure to PAHs through bivalve consumption does not impose harmful health effects upon consumers.

Pollution of the snow surface with polycyclic aromatic hydrocarbons during the formation of frost

When analyzing chemical compositions of snow the high variability of content of polycyclic aromatic hydrocarbons (PAHs) in snow cover between snowfalls is observed. Researchers explain this by concentrating of snow. However, another mechanism of atmospheric contamination of the snow cover surface is possible. It may be a precipitation of fine crystals of PAHs from the atmosphere in the composition of cryohydrates, which can form aerogenic anomalies on the snow surface at formation of hoarfrost. The process starts in the atmosphere during the interaction of finely dispersed crystals of PAHs with cloud supercooled drops. This results in the cryogenic concentration of solid particles of PAHs by way of formation of solid eutectic mixture – cryohydrates, which are a two-phase system consisting of a fine mixture of crystals of solid particles and ice. Evidence of their manifestation is the presence of the Forel hatching on the surface of the facets of the hoarfrost crystals appearing due to the different optical density of alternating zones, which consist of interpenetrating domains of crystallized solid aerosols and ice. At the same time, due to the presence of temperature inversion over the snow cover and its drying effect on the near-snow layer of air, a stable mass transport of water vapor down to the snow cover is formed, which can initiate the flow of fine cryohydrates from the PAHs. Therefore, the growth of atmospheric ice crystals, begun in the surface atmosphere, continues on the snow surface during formation of hoarfrost, thus creating a special nano-relief of snow cover. The paper presents the results of observations of changes in the concentration of individual PAHs in the upper 18 mm layer of snow at accumulation of the surface hoarfrost during a long period between snowfalls. Some micro-morphological features of the forms of skeletal rime micro-crystals are shown, with which an increase in the nano-roughness of the snow surface is associated, as well as the manifestation of the signal of the aerogenic PAH anomaly on the snow surface. Since the conditions for the formation of surface hoarfrost occur more often than for snowfalls, the hoarfrost may be an informative object of testing when detecting hydrocarbon contamination of snow cover during the intervals between snowfalls.

Polycyclic Aromatic Hydrocarbons in Sediment and Health Risk of Fish, Crab and Shrimp Around Atlas Cove, Nigeria.

Background.Polycyclic aromatic hydrocarbons (PAHs) are toxic contaminants and pose health risks to humans and the ecosystem due to their persistence in the environment.Objectives.This study determined the concentrations of PAHs in sediment, two species of fish (Drepane africana and Pomadasys jubelini), crabs (Callinectes amnicola) and shrimps (Penaeus notialis) around the Atlas Cove jetty, Lagos, Nigeria.Methods.Polycyclic aromatic hydrocarbons were extracted from fish, shrimp, and crabs that were purchased from local fishermen. Sediments were collected at five locations impacted by ship movement and cargo offloading around the Atlas Cove jetty during the period of June to August 2016, using standard methods. Potential toxicity of PAHs in the sediments on the surrounding aquatic organisms was assessed. The PAHs were analyzed using gas chromatography-mass spectrometry. Human health risk assessment was calculated from biota using dietary daily intake and carcinogenic potencies of individual PAH concentrations.Results.A total of 17 PAH congeners were detected in sediment samples and ten were detected in biota samples. Concentrations of total PAHs obtained in sediment and fish samples ranged from 2.15 - 36.46 mg/kg and 11.89 - 71.06 mg/kg, respectively. The total PAHs concentration pattern follow the order of P. notialis > C. amnicola > P. jubelini (whole) > D. africana (whole) > D. africana (fillet) > P. jubelini (fillet) > sediment. Concentrations of total PAHs were higher in whole fish than in fillet samples (muscle) in both fish species. High values of PAHs were recorded in the dietary intake (0.10 - 2.33 mg/kg body weight/day) of the organisms. Toxic equivalent quotient values (0.01 to 0.10 mg/kg) were observed to be higher than the screening values (0.0014 to 0.0599 mg/kg). In the muscle of Drepane africana and Pomadasys jubelini, splitting and atrophy of the muscle bundles were observed.Conclusions.The concentrations of PAHs in analyzed sediment and organisms were higher than the maximum permissible limit of the United State Environmental Protection Agency (USEPA). Most of the detected PAHs were of petrogenic origin, which is an indication that anthropogenic activities were influencing PAH concentrations.Competing Interests.The authors declare no competing financial interests.

Chemometric-assisted fast quantification and source apportionment of PAHs in PM10 using gas chromatography-mass spectrometry

ABSTRACT In this study, PM10 samples at four locations of Loudi, China were collected from January 2017 to March 2017 and December 2017 to February 2018 at first. Then, a new analytical strategy of second-order calibration based on the alternating trilinear decomposition (ATLD) coupled with gas chromatography-mass spectrometry (GC-MS) was firstly developed for quantitative analysis of seven polycyclic aromatic hydrocarbons (PAHs) in these samples. This strategy is more sensitive and efficient than traditional chromatography not only, but also it can resolve the problems of baseline drift and peaks overlapping in chromatographic analysis. Without the need for intricate pretreatment process and any derivation reactions, useful qualitative and quantitative information of seven PAHs was quickly extracted from the GC-MS-Sample data array by replacing chemical or physical separation with mathematical separation. In validation samples, the average recoveries of seven PAHs ranged from (96.7 ± 4.8) % to (107.9 ± 4.2) %, and the root-mean-square errors of prediction (RMSEPs) were within the range of 0.03–0.35 μg mL−1. The highest concentrations of individual PAHs in these samples were for phenanthrene (1.34 μg mL−1 in monitoring station), acenaphthylene (0.79 μg mL−1 in municipal government) and chrysene (0.53 μg mL−1 in monitoring station). Identified by component analysis, coal combustion and vehicle exhaust were the most possible sources of Loudi, China. These results demonstrated that the proposed method is characterised as a more precise, simple and promising analytical strategy to identify and quantify PAHs in actual aerosol.

Particle-associated polycyclic aromatic hydrocarbons in a representative urban location (indoor-outdoor) from South Europe: Assessment of potential sources and cancer risk to humans.

PM10 -bound polycyclic aromatic hydrocarbons (PAHs) levels were monitored at urban locations (outdoor/indoor) within the city of Madrid between May 2017 and April 2018. Fourteen PAH congeners were measured, potential emission sources were identified as were potential carcinogenic risks. The ΣPAHs averaged 0.577 and 0.186ng/m3 in outdoor and indoor air, with a high linear correlation per individual mean PAH and month. The largest contributors to the ΣPAHs were the high-molecular-weight PAHs. Principal component analysis-multiple linear regression results showed that emissions from diesel and vehicular processes explained 27% and 23% of the total variance of outdoor and indoor air, while combustion processes accounted for 30% and 25% in ambient and indoor air, respectively. During the cold season, biomass burning plus coal and wood combustion were additional sources of outdoor emissions. The heavy-, medium- and light-molecular-weight PAH originating from outdoor sources accounted for 72%, 80%, and ~60% of the indoor levels of the three respective PAH groups. Average BaP concentration was 0.029 and 0.016ng/m3 in outdoor and indoor air, respectively. Estimated BaPeq concentration averaged 0.072, 0.035, and 0.027ng/m3 for outdoor, indoor, and indoor-generated individual PAH concentrations, respectively. The estimated carcinogenic risk falls within the range of acceptable risk targeted by the US-EPA.