Priority Polycyclic Aromatic Hydrocarbons Research Articles

Seasonal variation, source identification, and health risk assessment of atmospheric polycyclic aromatic hydrocarbons (PAHs) in Ulsan, South Korea

Gaseous and particulate 21 PAHs were monitored at a residential site in Ulsan, South Korea, over three seasons (December 2013–August 2014). The mean concentrations of Σ21 PAHs were highest in winter (16.2 ± 8.2 ng/m3), followed by spring (8.37 ± 4.53 ng/m3) and summer (6.23 ± 2.53 ng/m3). The mean gaseous concentration of Σ21 PAHs (7.39 ± 4.39 ng/m3) was 2.7 times higher than that of particulate PAHs (2.70 ± 3.38 ng/m3). To identify the sources of PAHs (both types of sources and their areas), diagnostic ratios, principal component analysis, and concentration-weighted trajectory (CWT) were used. The results showed that pyrogenic sources (e.g., coal combustion) were the primary emission sources of PAHs in winter and spring. In summer, the influence of both coal and heavy oil combustion was dominant, suggesting that PAHs could be transported from industrial areas of Ulsan (e.g., petrochemical and nonferrous industrial complexes) by seasonal winds. Regarding emission source areas, the CWT analysis revealed that in winter and spring, PAHs in Ulsan could be attributed to emissions from regional areas, e.g., China and North Korea. The PAH concentrations were also used to assess the health risks associated with the inhalation of these compounds for adults aged 18–70. The results showed that the cancer risks from Σ19 PAHs and Σ13 PAHs did not exceed the guideline set by the US EPA (10−6), indicating no cancer risks for this target group. However, it is worth noting that certain PAHs, which are not listed as priority PAHs by the US EPA, make significant contributions to the benzo[a]pyrene equivalent and the associated cancer risks. Therefore, it is necessary to investigate not only the priority PAHs but also other PAH species to fully evaluate their effect on human health.

Characterization of calibration solution certified reference material for polycyclic aromatic hydrocarbons by exact matching isotopic dilution mass spectrometry: a case study from the Brazilian Metrology Institute

Abstract Recertification is a common practice in National Metrology Institutes whenever advances are made in certified reference material (CRM) characterization procedures, which play a key role in metrological traceability. This article compares measurements of 16 priority polycyclic aromatic hydrocarbons (PAHs) in toluene by gas chromatography isotopic dilution mass spectrometry (IDMS) using either an calibration curve or the exact matching approach. The multi-point IDMS calibration curve was used on the original CRM certification and the exact matching approach was carried out on its recertification. The measurement uncertainties by exact matching approach (0.3%–1.0%) were approximately 5 times smaller than those obtained using the calibration curve (1.5%–4.4%) for all PAHs, reducing the uncertainty component due to characterization of PAH CRM. This new characterization study added reliability, increased accuracy and reduced the measurement uncertainty of the Inmetro CRM, with metrological traceability to the International System of Units. The exact-matching isotope dilution is an important technique to value assign organic compounds in CRMs, an action that consolidates the chemical metrology in the Brazilian Metrology Institute.

Risk Assessments of Polycyclic Aromatic Hydrocarbons in the Surface Sediments of Drinking Water Sources in Ifite Ogwari, South-East Nigeria

ABSTRACT Surface water is the main source of drinking water in Ifite Ogwari, Anambra State, South-East Nigeria. In aquatic environments, sediment functions as both a source and a sink of polycyclic aromatic hydrocarbons (PAHs). To determine the level of pollution, health concerns to people and the environment, and potential sources of PAHs in the surface water sediments in Ifite Ogwari, sediment samples were collected from 9 surface water sources used for drinking by Ifite Ogwari people and were analyzed using a Gas Chromatography/Flame Ionization Detector (GC-FID). In all sediment samples, only 11 PAHs out of 16 United States Environmental Protection Agency (USEPA) priority PAHs were detected while 5 were below detectable limits. The concentration of benzo[a]anthracene was high but detected in only 2 sediment samples while fluoranthene has a relatively close concentration across all samples. Benzo[k]fluoranthene has the highest concentration compared to other PAHs in the samples while benzo[a]pyrene has the lowest concentration across all samples. Atammele sediment was analyzed as the most carcinogenic followed by Isiachala with concentrations of 84.23 ng/µL and 51.92 ng/µL respectively. Ube stream sediment has the lowest concentration of PAHs (11.74 ng/µL). Ecological risk of the PAHs revealed a sediment-to-sediment variation in the risk profile. Human health risk assessment depicts that hazard index and total cancer risk for adults and children ranged from 2.3E-07 - 2.57E-05 and 4.85E-07 - 5.43E-05 respectively. Pyrogenic activities are the main source of PAHs in the sediments. The results provide a guide for monitoring PAHs pollution and protecting drinking water sources.

Occurrence, source modeling, influencing factors and exposure assessment of polycyclic aromatic hydrocarbons in water sources: A mega-study from mainland China

This study investigates the composition and distribution of 16 priority polycyclic aromatic hydrocarbons (PAHs) in 70 water samples collected from centralized drinking water sources (CDWSs) across 30 provinces (cities) in mainland China. Additionally, water quality and socio-economic data were collected to determine the influencing factors. The study discovered that the total concentrations of 16 priority PAHs (Σ16PAHs) varied from 0.17 to 176.71ng/L (mean: 56.49 ± 38.58ng/L). Lakes and reservoirs had significantly higher concentrations of PAHs than groundwater. The primary pollutants were low-molecular-weight (LMW) PAHs, such as phenanthrene, naphthalene, and fluorene. There was a strong correlation between LMW PAHs and Σ16PAHs (p < 0.05). The mean Σ16PAHs in the seven geo-environmental zones were ranked as follows, under the comprehensive influence of emission density, natural, and social environmental factors: Northwest China (78.42 ± 66.96ng/L) > Northeast China (73.70 ± 33.23ng/L) > East China (64.35 ± 45.66ng/L) > North China (50.95 ± 31.87ng/L) > Southwest China (44.05 ± 32.56ng/L) > Central China (41.68 ± 19.44ng/L) > Southern China (40.99 ± 16.54ng/L). The source modeling analysis revealed that the majority of PAHs came from chemical production and metal smelting (42.36%), as well as from the combustion of coal, wood, and biomass (34.17%), and other mixed sources. In addition, the study found a strong correlation between water quality and socio-economic factors with concentrations of PAHs, indicating that these factors may contribute to the re-enrichment, transport, and transformation of PAHs in overlying water to varying degrees. The mean incremental lifetime cancer risk (ILCR) was lower than the risk threshold. These findings provide scientific references for managing hazardous substances in the aquatic environment.

Personal exposure monitoring to polycyclic aromatic hydrocarbons bound to size-segregated aerosol

Air pollution is a global problem, where impaired air quality significantly damages human health and the environment. Twenty-four hours of personal exposure to size-segregated airborne particulate matter (PM) and associated polycyclic aromatic hydrocarbons (PAHs) were measured in 129 non-smoking residents living in two Czech cities, Ostrava (an industrial area with high levels of air pollution) and Ceske Budejovice (an agricultural area with lower air pollution level) in various seasons between years 2018–2020. Particulate matter (PM) was sampled by cascade impactors based on their aerodynamic diameter (dae, μm) and divided into size fractions: coarse (2.5 < dae), fine (0.25 < dae < 2.5) and ultrafine (<0.25). Size distributions of 20 priority PAHs adsorbed on these PM fractions were analyzed by gas chromatography coupled to tandem mass spectrometry in electron ionization (GC-EI-MS/MS). The total concentration of ∑20PAHs to which residents were exposed ranged from 0.09 ng/m3 to 47.18 ng/m3. A higher level of PAHs was detected in Ostrava (mean: 5.59 ng/m3) than in Ceske Budejovice (mean: 1.96 ng/m3). Statistically significant concentration differences between PAHs in individual seasons were observed in both sampled localities, with higher concentrations measured in winter than in summer. Fine and ultrafine particles predominated in the mass composition of the particulate matter. The ultrafine particle size contained 67–80% of total PAHs. Respiratory health risk was estimated based on inhalation cancer risk (ICR). Cancer risk attributable to personal inhalation exposure ranged from 2.8 × 10−8 to 4.3 × 10−4. In winter, higher cancer risk were found in Ostrava, mainly caused by a high concentration of carcinogenic PAHs bound to ultrafine particles. Overall, the personal monitoring data confirmed a higher air pollution burden in the industrial area and the winter season and highlighted the importance of focusing on ultrafine particles as the main carriers of potentially mutagenic and carcinogenic substances, such as PAHs. In addition, personal monitoring data provided more detailed and accurate information on individual-level exposures, revealing significant differences in exposure concentrations in people living in the same area.

A systematic study on the chemical model of polycyclic aromatic hydrocarbons formation from nutrients (glucose, amino acids, fatty acids) in food

Polycyclic aromatic hydrocarbons (PAHs), prominent carcinogens formed during food processing, pose health risks through long-term consumption. This study focuses on 16 priority PAHs in the European Union, investigating their formation during pyrolysis. Glucose, amino acids and fatty acids are important food nutrients. To further explore whether these nutrients in food form PAHs during heating, a single chemical model method was used to heat these nutrients respectively, and GC–MS/MS was used to identify and quantify the obtained components. Glucose is the most basic nutrient in food, so the influence of water, pH, temperature and other factors on the formation of PAHs was studied in the glucose model. At the same time, the models of amino acids and fatty acids were used to assist in improving the entire nutrient research system. According to our results, some previously reported mechanisms of PAHs formation by fatty acids heating were confirmed. In addition, glucose and amino acids could also produce many PAHs after heating, and some conclusions were improved by comparing the intermediates of PAHs from three types of nutrients.

Concentration of Polycyclic Aromatic Hydrocarbons in Water from Hand-dug Wells in Some Communities in Ekpeyeland, Rivers State, Nigeria

Well water sources from selected communities in Ekpeyeland were assessed for the concentrations of polycyclic aromatic hydrocarbons (PAHs). The assessment was conducted seasonally in six communities. The concentrations of the PAHs were determined using standard methods and procedures and finally quantified by the use of GC-MS chromatography. The result showed the presence of all the 16 USEPA priority PAHs in the examined water samples. Seasonal variations were not significant. The summed values of PAHs from stations and seasons were above the permissible limit required for by WHO. Classification of the different categories of PAHs identified higher molecular weight (HMW) PAHs more in concentration than lower molecular weight (LMW) PAHs in the wells. Source identification proved that both pyrogenic and petrogenic sources were responsible for the presence of PAHs in the well water. However, pyrogenic source was the more prominent source of PAHs in the water. There was high level of carcinogenic PAHs in the water and thus the water portends danger to the users. Therefore, the locals are advised not to consume the water to avoid its effect on the long run.

Chemical characterization, source identification and potential health effects of PM2.5-bound non-polar organic compounds over a COALESCE network site - Bhopal, India

Year-long (2019) measurements of carbonaceous aerosols were performed at Bhopal, a regionally representative site as a part of the COALESCE (Carbonaceous Aerosol Emissions, Source apportionment and Climate Impacts) campaign. Aerosol-associated non-polar organic compounds (NPOCs) were analysed using thermal desorption (TD) Gas chromatography/Mass spectrometry (TD-GC/MS). The annual average of the total organic carbon (OC), elemental carbon (EC), and analysed PAHs (Polycyclic Aromatic Hydrocarbons), and n-alkanes were, 9.74 ± 9.47 μg m−3, 2.13 ± 3.12 μg m−3, 10.43 ± 5.49 ng m−3, and 114.93 ± 49.24 ng m−3, respectively. PAHs diagnostic ratios suggested emissions from petroleum, grass, wood, and coal combustion. Combustion derived PAHs (CombPAHs) accounted for 72.5 % of the total measured PAHs. During wintertime, based on Pyr/BaP ratio (∼0.6), gasoline exhaust emissions were higher compared to diesel exhaust emissions. The weak correlations between PAHs and meteorological parameters suggested that variations in PAH levels are primarily driven by alterations in emission sources. Total PAHs were correlated moderately with BrC (r2 = 0.60). The estimated lifetime lung cancer risk (LLCR) values on exposure to 16 USEPA priority PAHs (5 × 10−5) demonstrated that PAH levels in this region pose moderate health risks. Given observations from only campaign mode short-term measurements of NPOCs over India, this work provides a more comprehensive understanding of the concentrations, seasonal variations, and sources of n-alkanes and health risk associated with particle bound PAHs over the data-poor central Indian region.

Evaluation of Appropriate Conditions for Efficient Simultaneous Determination of US EPA and EU Priority Polycyclic Aromatic Hydrocarbons in Various Food Categories and Assessment of Their Consumption Risk.

The QuEChERS (quick, easy, cheap, effective, rugged and safe) conditions were optimized for efficient determination of the U.S. Environmental Protection Agency (US EPA) and European Union (EU) priority polycyclic aromatic hydrocarbons (PAHs) for the categories of grains, tuber & starchy vegetables, soy beans and products, fish & seafood, and poultry & meat, including raw materials and their corresponding products. The PAHs were analyzed using ultrahigh-performance liquid chromatography with temperature-controlled fluorescence detection and gas chromatography with tandem mass spectrometry. The established conditions had good accuracy, repeatability, and precision. Environmental pollution and processing methods influence the level of PAHs in samples. The low molecular weight PAHs were present in all raw materials, and processing increased high and low molecular weight PAHs in the products. The excess cancer risk for consumption of PAHs in cooked samples was mostly acceptable; a small number of samples might be of slight concern in certain age groups.

Removal of PAHs in paddy fields: How natural periphytic biofilm enhances the removal process and the mechanisms involved

Previous studies on the removal of polycyclic aromatic hydrocarbons (PAHs) from farmland have mostly relied on anthropogenic biotic or abiotic amendments. Here, an indigenous paddy periphytic biofilm (PB) composed of complex symbolic communities was enriched, and its essential role, as well as the potential mechanisms of PAHs dissipation, was investigated. A pot experiment revealed that PB achieved 92.87% and 92.76% removal of the USEPA priority PAHs from the overlying water and soil of a heavily PAHs-contaminated paddy field, respectively. This subsequently decreased ΣPAHs accumulation in rice shoots to 4.12 ± 1.08 ng g-1, under the thresholds based on food safety standards. The physiology of PB in an aquatic culture with PAHs was assessed to understand the toxicity and removal mechanism. Extracellular polymeric substances (EPS) adsorption occurred in the early stage, followed by late biodegradation, which was considered the primary mechanism for removing PAHs. In this process, the PB contributed more to the high molecular weight PAHs compared to the low molecular weight. Furthermore, 16S-rRNA sequencing demonstrated specific functional phyla (Proteobacteria, Ascomycota, and Chloroplastida) with significantly higher relative abundances in periphytic communities with PAHs, which facilitated PAHs degradation. The predicted synergetic metabolic pathway involved 33 PAHs-degrading genes as inferred by PICRUSt. These findings suggest that PB could provide a promising strategy for target PAHs remediation in situ and food safety in contaminated paddy fields.

Sunlight light-driven degradation of anthracene and naphthalene on robust Cu2+doped ZnO nanoparticles from simulated rainwater: optimization factors, kinetics, and reusability

This research investigated the detection and removal of priority polycyclic aromatic hydrocarbons (PAHs) from metropolitan rainwater runoff through photocatalytic degradation.

Probing the occurrence, sources and cancer risk assessment of polycyclic aromatic hydrocarbons in PM2.5 in a humid metropolitan city in China.

Fifty-two consecutive PM2.5 samples from December 2021 to February 2022 (the whole winter) were collected in the center of Chongqing, a humid metropolitan city in China. These samples were analysed for the 16 USEPA priority polycyclic aromatic hydrocarbons (16 PAHs) to explore their composition and sources, and to assess their cancer risks to humans. The total concentrations of the 16 PAHs (ng m-3) ranged from 16.45 to 174.15, with an average of 59.35 ± 21.45. Positive matrix factorization (PMF) indicated that traffic emissions were the major source (42.4%), followed by coal combustion/industrial emission (31.3%) and petroleum leakage/evaporation (26.3%). The contribution from traffic emission to the 16 PAHs increased from 40.0% in the non-episode days to as high as 46.2% in the air quality episode during the sampling period. The population attributable fraction (PAF) indicates that when the unit relative risk (URR) is 4.49, the number of lung cancer cases per million individuals under PAH exposure is 27 for adults and 38 for seniors, respectively. It was 5 for adults and 7 for seniors, when the URR is 1.3. The average incremental lifetime cancer risk (ILCR) for children, adolescents, adults and seniors was 0.25 × 10-6, 0.23 × 10-6, 0.71 × 10-6, and 1.26 × 10-6, respectively. The results of these two models complemented each other well, and both implied acceptable PAH exposure levels. Individual genetic susceptibility and exposure time were identified as the most sensitive parameters. The selection and use of parameters in risk assessment should be further deepened in subsequent studies to enhance the reliability of the assessment results.

Toxicological Risk Evaluation of Polycyclic Aromatic Hydrocarbons in Soils from a Petroleum Spillage Site at Kokori in the Niger Delta Region of Nigeria

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that are produced by the incomplete combustion of organic sources and are widely found in soils. This present research was carried out to evaluate the concentrations and toxicological risk assessment of the United States Environmental Protection Agency's sixteen priority polycyclic aromatic hydrocarbons (16 priority PAHs) in soils from the vicinity of an oil spillage site in Delta State of Nigeria. The level of pollution and potential toxicological health hazards of the PAHs were assessed in surface soil samples using soxhlet extraction of and Gas Chromatography-Mass Spectrometry (GC-MS). Thirteen out of the sixteen USEPA priority PAHs were detected in the soil sample. The concentrations of PAHs in the petroleum-contaminated soils in this investigation ranged from 0.01181 ppm to 1.16054 ppm, with the total estimated concentration of the 16 priority PAHs being 5.6713 ppm. Furthermore, the distribution of the PAHs in the study area was predominated by LMW PAHs (62%) over HMW PAHs (38%). Additionally, the total toxicity equivalency quotients TEQ (B[a]Peq) result of the carcinogenic potency of the USEPA priority PAHs was calculated as 0.08689 ppm (8.689%) and was discovered to be within the Canadian TEQ (B[a]Peq) threshold of 0.6 ppm. This suggests that the soil in the study area is safe based on the Canadian TEQ (B[a]Peq) standard and does not constitute a carcinogenic risk. However, the long-term bioaccumulation of these low quantities of PAHs in human has been found to constitute a potential health concern due to bioaccumulation in living systems.

The occurrence characteristics, removal efficiency, and risk assessment of polycyclic aromatic hydrocarbons in sewage sludges from across China

Sewage sludge is considered to be an important sink for polycyclic aromatic hydrocarbons (PAHs) in wastewater treatment plants and the potential risks from sludge contaminated with PAHs during land application has attracted attention. To identify the priority PAHs for control and enhance their removal from sludge, the occurrence characteristics, removal efficiency, and risk assessment of PAHs in sewage sludges from across China were analyzed. Data collection was from 2001 to 2023. Results showed that 16 PAHs were widely detected in Chinese sewage sludge with total amounts (∑16PAHs) between 0.06 and 34.93 mg kg dw−1. Fossil fuel, coal, and biomass combustion are main anthropogenic sources of PAHs in China. In general, phenanthrene (PHE), anthracene (ANT), fluorescein (FL), chrysene (CHR), pyrene (PYR), and benzo[b]fluoranthene (BbF) are regarded as the main components and PAHs with 3–5 rings dominate (84.01%–91.53%) sewage sludge in China. Although aerobic composting and anaerobic treatment significantly improve ∑16PAHs removal, sludge stabilization treatment only reduced the risk by a small amount, especially for high-molecular-weight (HMW) PAHs. The benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), and dibenzo[a,h]anthracene (DahA) are proposed as the priority control contaminants for sewage sludge in China because they have consistently high-risk quotient (RQ) values of 2.42–7.47, 1.28–3.16, 1.06–1.83 before and after sludge stabilization, respectively. More attention should be paid to BaA, BbF, benzo[k]fluoranthene (BkF), BaP, DahA, and indeno[1,2,3-cd]pyrene (IcdP) in Beijing; ANT, BaA, and BaP in Shanghai; and BaA and BaP in Guanghzou. Although the toxic equivalent quotient (TEQ) for PAHs met the limit concentration requirements of the national standard, the potential health risks due to long-term exposure to HMW PAHs cannot be ignored because the incremental lifetime cancer risk (ILCR) was consistently in the risk threshold range (>1 × 10−6). Some suggestions on enhanced treatment approaches and land use standards are proposed to further alleviate the risk from HMW PAHs.

Comparative study on anthropogenic impacts on soil PAHs: Accumulation and source apportionment in tourist and industrial cities in Hebei Province, China

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic contaminants in urban soils. The accumulation and source identifications of PAHs within a city have been frequently studied. However, impacts of urbanization development modes on PAHs accumulation patterns by taking a city as a whole have been seldom reported. Four cities with two development modes in Hebei province, Chengde and Zhangjiakou (tourist cities) and Handan and Tangshan (industrial cities), were selected. The concentrations of 16 priority PAHs in soils in the study areas were investigated. The results showed that the average concentrations of Σ16PAHs in Handan (2517 μg/kg) and Tangshan (2256 μg/kg) were more than twice of those in Chengde (696 μg/kg) and Zhangjiakou (926 μg/kg) approximately. Lines of evidence, provided by a combination of diagnostic ratios, pairwise correlation, and PMF methods, revealed that the dominant sources of PAHs in either city were industrial emission, vehicle emission, and petrogenic/biogenic process but with different proportions. Linear fittings based on Bayesian kernel machine regression analysis (BKMR) were constructed to illustrate the impact of industrialization on PAHs accumulation. The probability of excessing the 10 % (376 μg/kg) and 50 % (1138 μg/kg) of current ∑16PAHs would be higher than 90 % given the gross industrial production per unit area >5.00 × 106 and 20.5 × 106 CNY/km2, respectively. The proposed threshold values of industrialization are of significance for determining industrial structure and proportion in urban management.

Human health risk assessment of PM10-bound heavy metals and PAHs around the Latin America’s Largest opencast coal mine

Air pollution in opencast coal mine areas is a critical issue, resulting in harmful severe effects on human health. Therefore, it is essential to understand the air pollution factors and to assess the risks to humans. This study evaluated the potential risks (carcinogen and non-carcinogen) of inhalation exposure to PM10-bound heavy metals and Polycyclic Aromatic Hydrocarbons (PAHs) in an open pit mine in northern Colombia. During February-May 2022, PM10 samples were collected at eight sites. Heavy metals (i.e., Al, Cr(VI), Mn, Cu, Zn, As, Pb) and PAHs (thirteen priority PAHs, and one non-priority PAH) levels linked to PM10 were analyzed by X-ray fluorescence and gas chromatography–mass spectrometry, respectively. PM10 concentrations were found to range between 4.70 and 59.90 µg m−3. Out of the three different zones of the study area (i.e., North Zone, South Zone, and Populated Zone), the North Zone recorded the highest daily average concentrations of Cr(VI) (104.16 ng m−3), Mn (28.39 ng m−3), Cu (33.75 ng m−3), Zn (57.99 ng m−3), As (44.92 ng m−3), and Pb (27.13 ng m−3). The fraction of the analyzed heavy metals at all monitoring sites was 82%–89% for Al, followed by Cr(VI) with 3%–6%. Cr(VI) was the major contributor to the carcinogenic risk values, while Cu, Cr(VI), and As were the main drivers for the non-carcinogenic risk. The average cancer risk range for heavy metals was 3.30 × 10–04 –5.47 × 10–04. On the other hand, the cancer risk for PAHs exposure was acceptable. The average incremental lifetime cancer risk (ILCR) values varied between 2.87 × 10–07 and 4.21 × 10–07. Benzo[a]pyrene contributed to 54%–56% of the total risk from inhalation of PM10-bound PAHs, while Indeno[1,2,3-cd]pyrene contributed to 16%–19%. Based on the Monte Carlo sensitivity analysis, exposure to Cr(VI) was the main factor affecting cancer risk in the North, South, and Populated Zones. A suitable risk assessment and management plan requires understanding PM10-bound heavy metals and PAHs concentration levels as well as their potential health risks, mainly in open-cast coal mine zones. Our study found that people living near open-pit mines face potential health risks, so it is crucial to establish policies and regulations to control emission sources.

Source, distribution, and risk assessment of polycyclic aromatic hydrocarbons in sediment and fish samples from River Owan, Edo State, Nigeria

Polycyclic aromatic hydrocarbons (PAHs) are persistent environmental contaminants that present several environmental risks including human health. The 16 priority PAHs including its 1-methylnaphthalene, and 2-methylnaphthalene were determined in sediment and fish samples (Clarias anguillaris and Oreochromis niloticus) of River Owan, Edo State, Nigeria using gas chromatography (GC) equipped with flame ionization detector (FID) and other standard laboratory protocols. The isomeric ratio was used for source diagnosis, sediment quality guidelines, and risk models of incremental lifetime cancer were used for risk assessment. 1-methylnaphthalene and 2-methylnaphthalene were most predominant in all sediment samples analysed. The ∑LMW PAHs ranged between 0.093—0.250 μg/kg; ∑HMW PAHs were 0.107—0.579 μg/kg. The sediment samples range for ∑PAHs was 0.280–0.810 μg/kg with concentration order of increase: SE5&amp;gt;SE4&amp;gt;SE3&amp;gt;SE6&amp;gt;SE1&amp;gt;SE2&amp;gt;SE7 for the seven sampling locations. The ∑PAHs for Oreochromis niloticus was 0.190 μg/kg, which is higher than the value of Clarias anguillaris 0.080 μg/kg, and these values were greatly lesser when compared to the European Commission limit of 12.00 μg/kg. The diagnostic ratio indicates that the sources are more pyrogenic than petrogenic, revealing combustion from grass, wood, and bush burning. Sediment quality assessment showed that the ∑PAHs were lower than the regulatory values of sediment quality guidelines (SQG) assessment suggesting no ecotoxicological effects on the benthic organisms in this area at present. The Incremental Life Cancer Risk results were in the range of 9.15 × 10−12—1.46 × 10−6 for children, and 7.78 × 10−12—1.76 × 10−6 for adults considering the three routes of exposure. The incremental life cancer risk assessment showed a negligible risk.

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.

Distribution and transfer rules of polycyclic aromatic hydrocarbons in soil-wheat ecosystems in China.

The translocation and accumulation patterns of polycyclic aromatic hydrocarbons (PAHs) in the soil-crop system have important implications for the fate of PAHs and human health. This study summarized the concentrations of 16 priority PAHs in the soils and various parts of mature winter wheat in China, sourced from a screening of previous literature in English and Chinese databases. The study analyzes the distribution characteristics, transfer patterns, and human health risks of PAHs in sites studied in Shaanxi, Henan, and Shandong provinces. The results showed that the concentrations of Σ16 PAHs in the rhizosphere soil of wheat ranged from 10.30 to 893.68 ng/g, in descending order of Shaanxi > Henan > average > Shandong. In sites with mild to moderate contamination (200 < Σ16 PAHs < 600 ng/g; i.e., Henan and Shaanxi), the concentration of Σ16 PAHs in the roots was higher than that in the stems or the grains, while in contamination-free sites (Σ16 PAHs < 200 ng/g; i.e., Shandong), the highest concentration of Σ16 PAHs was found in the stems. Generally, the concentrations of PAHs increased in the order of roots-stems-grains. The predominant PAHs in each part of wheat were 2- or 3-ring compounds, with five- or six-ring PAHs being more prevalent in wheat from Shanghe, Shandong. The bioaccumulation factors of different wheat parts from Shaanxi and Henan were consistently smaller than 1, and low- and medium-ring (2-4 rings) PAHs had bigger bioconcentration factors than high-ring (5-6 rings) PAHs. However, the accumulation of PAHs in the aboveground parts of wheat was larger than that in the underground parts of the Shandong sites. The linear regression relationship between the octanol-water partition coefficient and root concentration factor (RCF) of PAHs reflected that low and medium-ring PAHs were more easily absorbed by wheat roots than high-ring PAHs in Shaanxi and Henan. Our assessment of the health risks of oral wheat intake in adults and children by the incremental lifetime cancer risk (ILCR) model found a potential carcinogenic risk for both age groups in each province, with higher risks in adults than in children.

The seasonal change of PAHs in Svalbard surface snow

The Arctic region is threatened by contamination deriving from both long-range pollution and local human activities. Polycyclic Aromatic Hydrocarbons (PAHs) are environmental tracers of emission, transport and deposition processes. A first campaign has been conducted at Ny-Ålesund, Svalbard, from October 2018 to May 2019, monitoring weekly concentrations of PAHs in Arctic surface snow. The trend of the 16 high priority PAH compounds showed that long-range inputs occurred mainly in the winter, with concentrations ranging from 0.8 ng L−1 to 37 ng L−1. In contrast to this, the most abundant analyte retene, showed an opposite seasonal trend with highest values in autumn and late spring (up to 97 ng L−1), while in winter this compound remained below 3 ng L−1. This is most likely due to local contributions from outcropping coal deposits and stockpiles. Our results show a general agreement with the atmospheric signal, although significant skews can be attributed to post-depositional processes, wind erosion, melting episodes and redistribution.