Polycyclic Aromatic Hydrocarbons Components Research Articles

An extensive investigation on human risk associated with PAHs in fish and sediment in Bushehr, Northern of Persian Gulf

Here, a comprehensive study was designed to estimate the human risk assessment attributed to exposure of polycyclic aromatic hydrocarbons (PAHs)in sediment and fish in most polluted shore area in north of Persian Gulf. To this end, a total of 20 sediment and inhabitual Fish, as one of most commercial fish, samples were randomly collected from 20 different stations along Bushehr Province coastline. The 16 different components of PAHs were extracted from sediment and edible parts of inhabitual fish and measured with high-performance liquid chromatography (HPLC) and gas chromatography (GC), respectively. In addition, dietary daily intake (DDI) values of PAHs via ingestion Indian halibut and the incremental lifetime cancer risk (ILCR) attributed to human exposure to sediments PAHs via (a) inhalation, (b) ingestion, and (c) dermal contact for two groups of ages: children (1–11 years) and adults (18–70 years) were estimated. The results indicated that all individual PAHs except for Benzo(b)flouranthene (BbF) and Benzo(ghi) perylene (BgP) were detected in different sediment sample throughout the study area with average concentration between 2.275 ± 4.993 mg.kg–1 dw. Furthermore, Naphthalene (Nap) with highest average concentration of 3.906 ± 3.039 mg.kg–1 dw was measured at the Indian halibut. In addition, the human risk analysis indicated that excess cancer risk (ECR) attributed to PAHs in sediment and fish in Asaluyeh with high industrial activities on oil and derivatives were higher the value recommended by USEPA (10−6). Therefore, a comprehensive analysis on spatial distribution and human risk assessment of PAHs in sediment and fish can improve the awareness on environmental threat in order to aid authorities and decision maker to find a sustainable solution.

Evaluation of surfactant-aided polycyclic aromatic hydrocarbon biodegradation by molecular docking and molecular dynamic simulation in the marine environment

Marine oil spills directly cause polycyclic aromatic hydrocarbons (PAHs) pollution and affect marine organisms due to their toxic property. Chemical and bio-based dispersants composed of surfactants and solvents are considered effective oil spill-treating agents. Dispersants enhance oil biodegradation in the marine environment by rapidly increasing their solubility in the water column. However, the effect of dispersants, especially surfactants, on PAHs degradation by enzymes produced by microorganisms has not been studied at the molecular level. The role of the cytochrome P450 (CYP) enzyme in converting contaminants into reactive metabolites during the biodegradation process has been evidenced, but the activity in the presence of surfactants is still ambiguous. Thus, this study focused on the evaluation of the impact of chemical and bio-surfactants (i.e., Tween 80 (TWE) and Surfactin (SUC)) on the biodegradation of naphthalene (NAP), chrysene (CHR), and pyrene (PYR), the representative components of PAHs, with CYP enzyme from microalgae Parachlorella kessleri using molecular docking and molecular dynamics (MD) simulation. The molecular docking analysis revealed that PAHs bound to residues at the CYP active site through hydrophobic interactions for biodegradation. The MD simulation showed that the surfactant addition changed the enzyme conformation in the CYP-PAH complexes to provide more interactions between the enzyme and PAHs. This led to an increase in the enzyme's capability to degrade PAHs. Binding free energy (ΔG‌‌Bind) calculations confirmed that surfactant treatment could enhance PAHs degradation by the enzyme. The SUC gave a better result on NAP and PYR biodegradation based on ΔG‌‌Bind, while TWE facilitated the biodegradation of CHR. The research outputs could greatly facilitate evaluating the behaviors of oil spill-treating agents and oil spill response operations in the marine environment.

Quantifying the impact of anthropogenic emissions and aquatic environmental impacts on sedimentary mercury variations in a typical urban river

In urban and industrial regions, sedimentary mercury (Hg) serves as the crucial indicator for Hg pollution, posing potential risks to ecology and human health. The physicochemical processes of Hg in aquatic environments are influenced by various factors such as anthropogenic emissions and aquatic environmental impacts, making it challenging to quantify the drivers of total mercury (THg) variations. Here, we analyzed the spatiotemporal variations, quantified driving factors, and assessed accumulation risks of sedimentary THg from the mainstream of a typical urban river (Haihe River). THg in the urban region (37−3237 ng g−1) was significantly higher (t-test, p < 0.01) than in suburban (71−2317 ng g−1) and developing regions (156−916 ng g−1). The sedimentary THg in suburban and developing regions increased from 2003 to 2018, indicating the elevated atmospheric deposition of Hg. Together with the temperature, grain size of sediments, total organic carbon (TOC), the pH and salinity of water, 40 components of parent and substituted polycyclic aromatic hydrocarbons (PAHs) were first introduced to quantify the driver of sedimentary THg based on generalized additive model. Results showed that anthropogenic emissions, including three PAHs components (31%) and TOC (63%), accounted for 94% of sedimentary THg variations. The aquatic environmental impacts accounted for 5% of sedimentary THg variations. The geo-accumulation index of THg indicated moderate to heavy accumulation in the urban region. This study demonstrates that homologous pollutants such as PAHs can be used to trace sources and variations of Hg pollution, supporting their co-regulation as international conventions regulate pollutants.

Thermal degradation kinetics, thermodynamics and pyrolysis behaviour of polycarbonate by TGA and Py-GC/MS

This paper elucidates the thermal and catalytic (mordenite and y-zeolite) pyrolysis characteristics of Polycarbonate (PC) as well the kinetics and thermodynamic parameters of the thermal decomposition of PC. Three distinct isoconversional methods, namely the Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), and Starkin methods, were employed to evaluate the kinetic and thermodynamic parameters. The average activation energies determined with the KAS, FWO, and Starink methods were 245.81, 235.36, and 249.99 kJ/mol respectively, and they were reduced by 17 % and 21 % when mordenite and y-zeolite were utilized as catalysts, respectively, according to the calculations performed with the KAS method. Py-GC/MS analyses showed that phenolic components were found to be dominant in the oil product obtained under non-catalytic conditions. Micropores in the structure of y-zeolite constitute 54.4 % of the total surface area, while micropores in the structure of mordenite constitute 95.5 % of the total surface area. Depending on the structure of the catalysts used, phenolic components decreased slightly, and aromatic and PAH (Polycyclic Aromatic Hydrocarbons) components replaced these components. As a result, phenolic compounds in the oil product obtained with y-zeolite (56.7 %) were less than those produced with mordenite (61.02 %). PAHs were 12.9 % and 7.5 % in the presence of y-zeolite and mordenite, respectively. Thus, the results evidence the molecular size of zeolite catalysts, as well as their acidic structure, which are crucial factors in the conversion of phenolic compounds.

The potential accumulation of polycyclic aromatic hydrocarbons in macroalgae from the Egyptian coast of the Red Sea

In the marine environment, polycyclic aromatic hydrocarbons (PAHs) constitute one of the most pervasive and harmful types of organic pollutants. They pose an additional hazard to marine creatures' resilience due to ongoing climatic change. Therefore, determining their concentration and source is important for estimating their possible risks. Utilizing (GC–MS), we analyzed PAH levels in marine algal tissues along the Red Sea's Ras Gharib coastline. The present study covered the collection of seven Red Sea macroalgae namely; Sargassum cinereum, Caulerpa racemosa, Ulva intestinalisLinnaeus, 1753, Turbinaria ornata, Hormophysa cuneiformis, Ulva lactuca, and Cystoseira myrica) from the RasGharib coastline. Sixteen PAHs were found at quantities ranging from 159.67 to 261.57 ng/g in all of the examined marine algal tissues. The average concentration of the 16 PAHs was the highest in S. cinereum and the lowest in U. lactuca. The mean concentration of benzo(a)anthracene (BaA) in S. cinereum was 74.12 parts per billion (ng g−1). Two- and three-ringed PAHs with a lower molecular weight amounted to 2.51 to 23.54% of all PAH components in algal tissues. The average contribution of the eight cancer-causing PAHs to the total TEQcarc of the investigated species was sequentially as follows: BaP (50.23%), BaA (32.18%), BbF (6.52%), BkF (5.20%), IP (4.50%), and Chr (2.00%). The results of the diagnostic ratios demonstrated that the primary causes of most PAHs were combined pyrogenic and petrogenic activities. This suggests employing these indicators to investigate the biological impacts of PAHs pollution and establish its bioavailability in the marine environment.

Soil Washing to Eliminate Polycyclic Aromatic Hydrocarbons from Petroleum Contaminated Soil - Temperature Effect

This study’s goals were to identify the components of polycyclic aromatic hydrocarbons (PAHs) in soil samples polluted with petroleum and to ascertain how temperature affected the removal of PAHs pollutants from petroleum-contaminated soil. The concentration of contaminants in the soil samples decreased from 46.22-12.07 ppm to 77.01-30.06 ppm at a temperature increase of 20–160°C, as shown by the results of this study, which are also supported by the percentage removal efficiencies of 22.22–79.69% and 32.90–73.81% for samples M and S, respectively. It was further discovered that 160℃ was the ideal temperature range for soil washing to eliminate the pollutants. High removal efficiency values demonstrated the efficacy of the soil washing approach in removing pollutants with high PAH concentrations. This information can help in the creation of more successful and affordable soil remediation techniques.

Toxicity of fresh and aged anthropogenic smoke particles emitted from different burning conditions

There is substantial evidence that photochemical reactions in the atmosphere cause physico-chemical transformation of combustion smoke, but how this processing modifies potential health effects in exposed populations is not well understood. Here we utilized a new approach to simulate photochemical aging of anthropogenic smoke emissions (a mixture of plastic, plywood, and cardboard smoke) from two different burning conditions (smoldering vs. flaming) and investigated their adverse outcomes associated with mutagenic activity and the relative potencies of different polycyclic aromatic hydrocarbons (PAHs). Aging resulted in increased oxygenated volatile organic compound (VOC) emissions but largely degraded particle-bound PAH components in the smoke. Chemical transformation during aging was more dramatic for flaming versus smoldering smoke. Due to the PAH degradation, mutagenicity of the aged smoke from flaming combustion was much lower (up to 4 times) than that of the fresh smoke on per-particle mass basis. However, on the basis of particle emitted per fuel mass burned, the aged and fresh smoke particles exhibited similar mutagenic activities, which were up to 3 times higher for smoldering versus flaming smoke emissions. Similarly, the PAH toxicity equivalent (PAH-TEQ) of the aged smoldering smoke was 3 times higher than that of the aged flaming smoke particles, suggesting that some PAHs (e.g., indeno[c,d]pyrene and benzo[b]fluoranthene) in the smoldering smoke were more photochemically stable during aging. These findings increase understanding of the evolution of smoke emitted at different burning conditions and the role of photochemical transformations on mutagenicity and PAH-induced toxicity.

Distribution, composition and risk assessment of PAHs and PCBs in cryospheric watersheds of the eastern Tibetan Plateau

Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) are significant components of persistent organic pollutants (POPs) and pose a threat to both ecosystems and human health. To explore their spatial distribution, origins, and risk assessment, we collected 25 glacial meltwater and downstream river water samples in the eastern Tibetan Plateau (including the Qilian Mountains in the northeast) during the summer of 2022 (June–July). Our results showed that ∑PAHs and ∑PCBs were present in a wide range from ND-1380 ng/L and ND-1421 ng/L, respectively. Compared to other studies worldwide, the ∑PAHs and ∑PCBs in the Hengduan Mountains were at high levels. The PAHs and PCBs mainly consisted of low-molecular-weight homologs, including Ace, Flu, Phe, and PCB52. Phe was the primary component of PAHs. Glacial meltwater samples generally exhibited low concentration of PAHs and PCB52, whereas downstream river water samples typically showed high concentration of PAHs and PCB52. We attributed this characteristic to the influence of pollutants physicochemical properties, altitude effect, long-range transport (LRT), and local environmental conditions. In the eastern Tibetan Plateau glacier basin (especially in the Hailuogou watersheds), the concentration of PAHs and PCB52 in runoff generally increased with decreasing elevation. We believe that the primary factor affecting the concentration of PAHs and PCB52 in the region is the difference in local human activity inputs from various altitudes. The composition characteristics of PAHs and PCBs suggested that incomplete coal combustion and coking discharge mainly caused PAHs, while the combustion of coal and charcoal and the release of capacitors primarily caused PCBs. We assessed the carcinogenic risk of PAHs and PCBs in the glacier basin of the TP and found that the potential threat of PAHs was stronger than that of PCBs. Overall, this study provides new insights into the ecological security of water resources in eastern Tibetan Plateau. It is significant for controlling PAHs and PCBs emissions, assessing the ecological environment of the glacier watershed, and regional human health.

Assessment of polycyclic aromatic hydrocarbons (PAHs) in alcoholic beverages consumed in Awka, Southeast Nigeria

ABSTRACT. The aim of this investigation was to assess the presence of 16 PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, anthracene, phenanthrene fluoranthene, benz[a]anthracene, pyrene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[ghi]perylene, and indeno[1,2,3-cd]pyrene with symbols Nap, Ace, Ane, Flu, Ant, Phe, Flt, BaA, Pyr, Chr, BbF, BkF, BaP, DahA, BghiP and InP, respectively) in alcoholic beverages consumed in Awka, Southeast Nigeria. The samples used were sourced from international, national, and local-based alcoholic beverages sold in Nigeria, which were analysed for the 16 priority PAHs components using gas chromatography-flame ionization detector (GC-FID) in order to quantify and offer advice to the public on the health implications of consuming these alcoholic beverages. The results show the absence of all the PAHs in all the alcoholic beverages, which could be due to lower temperature and shorter production duration utilized in the production process. This is because during the intense heating of raw materials or additives, PAHs are released. Therefore, the consumption of these alcoholic beverages is safe for consumers and poses no health risk that is detrimental to adults or children. As such, further research into other micropollutants and toxins is advocated to maintain current good manufacturing practices for quality.&#x0D; KEY WORDS: Alcoholic beverages, Food analysis, Public health, PAHs, GC-FID, Southeast Nigeria&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2023, 37(4), 805-815. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v37i4.1 &#x0D;

Correlation between polycyclic aromatic hydrocarbons component phenanthrene and clinical indicators in patients on peritoneal dialysis

Objective: To explore the correlation between polycyclic aromatic hydrocarbons (PAHs) component phenanthrene and clinical indicators in patients on continuous ambulatory peritoneal dialysis (CAPD). Methods: A total of 22 patients who underwent peritoneal dialysis catheterization and regular dialysis in the First Affiliated Hospital of Zhengzhou University from June to August 2018 were selected. Meanwhile, 18 healthy adults who underwent physical examination were also selected as the control group. Fasting blood samples were taken to detect the concentration of PAHs components for comparison, and the correlation between PAHs components and clinical indicators was further analyzed. Results: There were 22 cases in CAPD group (13 males and 9 females), and aged (45±13) years, while there were 18 cases in control group (6 males and 12 females), and aged (41±13) years. The concentration of blood phenanthrene (PHE) was the highest in CAPD group [0.449 (0.254, 0.581) mg/L], and it was only lower than acenaphthene in the control group [0.081 (0.050, 0.444) mg/L], with a statistically significant difference between the two groups (P=0.008). The analysis of PHE and clinical indicators showed that the concentration of PHE in CAPD patients was negatively correlated with weekly urea clearance index (Kt/V), weekly creatinine clearance (Ccr) and leukocyte level, but positively correlated with triglyceride level (r=-0.743, -0.749, -0.655 and 0.610, respectively, all P<0.05). Simple linear regression analysis demonstrated that for every 0.1 mg/L increase in PHE concentration, weekly Kt/V, weekly Ccr and white blood cell count decreased by 0.226, 3.050 L/1.73 m2 and 0.512×109/L, respectively, but triglyceride level increased by 0.152 mmol/L (all P<0.05). Multiple linear regression analysis revealed that the blood PHE concentration of CAPD patients was negatively correlated with weekly Kt/V and Ccr levels (t=-2.402 and -2.368, respectively, both P<0.05). All CAPD patients were followed up for 3 years, during which 8 patients (36.4%) withdrew from peritoneal dialysis due to technical failure, and the baseline PHE concentration was higher than that of patients who did not quit peritoneal dialysis [0.572 (0.416, 0.662) vs 0.268 (0.120, 0.475) mg/L, P=0.003]. Eight patients (36.4%) had cardiovascular events, and the baseline blood PHE concentration was higher than that of patients without cardiovascular events [0.542 (0.389, 0.741) vs 0.373 (0.157, 0.545) mg/L, P=0.045]. Conclusion: PHE correlates with clinical indicators of CAPD patients, including Kt/v, Ccr, leukocyte and triglyceride.

Studies on polycyclic aromatic hydrocarbon (PAH) concentration on smoke dried African Catfish (Clarias gariepinus) Using Difernet Localized Smoke Drying Equipment

The study of the Polycyclic Aromatic Hydrocarbons (PAH) concentration of smoke dried Clarias gariepinus, using different smoking methods (Smoking Drum, Chorkor and Smoking kiln), with hardwood as source of energy, to determine which traditional method produced the best and safest smoke dried fish in terms of lowest PAH concentration for human consumption. The PAH components were determined using Gas Chromatography/Mass Spectrometer (GC/MS) analysis. The results obtained were statistically analysed using SPSS (version 20.0) windows software. The PAH mean concentration and standard error mean (S.E.M), were calculated for each method and results were subjected to one way ANOVA at 0.05% significant level. There were significant difference (p&lt;0.05) in the PAHs mean concentration values of (Pyrene, Benzo(g-h)perylene, 1-2 Benzanthracene, Benzo(a)Pyrene, Dibenzyl(a-h)anthracene, Fluorene, Benzo(k)Fluoranthene, Phenanthrene (0.57±0.66, 0.44±0.15, 0.41±0.28, 0.37±0.28, 0.27±0.03, 0.18±0.20, 0.13±0.26, 0.13±0.16) respectively, in fish smoked dried with smoking kiln, and those smoked with chorkor and drum fo PAH mean concentration of (0.25±0.50, 0.30±0.14, o.23±0.27, 0.25±0.20, 0.21±0.29, o.13±0.21, 0.09±0.18, 0.07±0.15 and (0.38±0.52, 0.23±0.19, 0.20±0.33, 0.33±0.12, 0.14±0.17. 0.09±0.18, 0.02±0.03) respectively. There was no significant difference in (p&gt;0.05) in the PAH mean concentration values of Acenaphthylene and Naphthalene of fish samples smoked dried with chorkor and drum with (0.13±0.15, 0.16±0.20) and (0.12±0.13, 0.16±0.20) respectively, while Anthracene and kylene were absent in the fish samples smoked dried using all the methods. The PAH content of all the fish samples, were within the permissible limits of 2ppb set by the European Commission Regulation and are safe for human consumption. Benzo(a)pyrene (BaP)as a marker, did not exceed the maximum permissible limit and therefore safe for human consumption. It is recommended that fish processors should be sensitized on the genetoxic and carcinogenic effects of PAHs on the health of consumers of smoked dried fish.

Polycyclic Aromatic Hydrocarbons Pollution Characteristics in Agricultural Soils of the Pearl River Delta Region, China.

In order to investigate the pollution status of polycyclic aromatic hydrocarbons (PAHs) in the agricultural soil, 240 agricultural soil topsoil samples were collected from nine Pearl River Delta cities from June to September 2019. In addition, 72 samples were collected for vertical soil profiles, which soil profiles were excavated to a depth of 80 cm. After sample preparation, GC-MS was used for the separation of compounds on a HP-5MS quartz capillary column. ArcGIS software was used to map the spatial distribution. Health risk assessment was conducted using USEPA standard. The results showed that the total concentration of 16 PAHs ranged from 43.4 to 5630 ng/g, with an average of 219 ng/g. The spatial distribution showed that most of the seriously polluted areas were in the coastal area, near the port, and there was point source pollution in the Gaoming of Foshan. Vertically distributed display Zhuhai, Jiangmen, Zhaoqing, Shenzhen and Dongguan increased and then decreased from bottom to bottom, showing a low-high-low pattern, the concentration of PAHs in Zhongshan and Foshan decreased with the soil depth, while the concentration of PAHs in Guangzhou and Huizhou was enriched with human activities. The PAHs components in soil samples were mainly medium and high rings (4−6 rings). The analysis of the origin of PAH in soil samples showed that the mixture of incomplete combustion sources of fossil fuels such as coal and biomass and traffic emission sources were the main sources of soil PAHs. A small amount can be attributed to oil sources such as oil spills. The human health risk assessment showed no cancer risk for children, while for adults, may cause a potential risk of cancer, which needs to be noticed. Spearman correlation analysis showed that PAH content was significantly correlated with SOC (p < 0.01) and pH (p < 0.05). Port transport, road emissions and industrial production make the area a pollution hot topic, and supervision should be strengthened to protect the environment and food safety.

Benzo[b]fluoranthene (B[b]F) affects apoptosis, oxidative stress, mitochondrial membrane potential and expressions of blood-brain barrier markers in microvascular endothelial cells

Exposure to polycyclic aromatic hydrocarbons (PAHs) contributes to the damage of blood-brain barrier. While a number of studies were focused on benzo[a]pyrene, direct effects and mechanisms of benzo[b]fluoranthene (B[b]F), another main component of PAHs, on blood-brain barrier (BBB) are not documented. Here, we investigated if B[b]F at concentrations of environmental relevance could affect apoptosis, oxidative stress, mitochondrial membrane potential (MMP) and BBB marker expression in mouse brain microvascular endothelial (bEnd.3) cells, an in vitro model typically used to study BBB toxicology. Cells were treated with varying concentrations of B[b]F (0, 10, 20 and 40 μM) for 48 h. Cell proliferation, cell cycle, apoptosis, oxidative stress, MMP and BBB marker expressions were evaluated by label-free real-time cell analysis, flow cytometry, immunofluorescence and Western-blot. The proliferation of bEnd.3 cells was inhibited by B[b]F in a concentration dependent manner. B[b]F treatment significantly affected cell cycle, induced apoptosis, increased levels of reactive oxygen species (ROS) and disputed MMP. Expressions of BBB marker Occludin and Claudin-5 were decreased in the presence of 40 μM B[b]F. In conclusion, B[b]F might damage BBB by affecting proliferation, apoptosis, ROS level and Occludin and Claudin-5 expressions in microvascular endothelial cells.

Heavy Metal Contamination Index, Metal Index and Polycyclic Aromatic Hydrocarbon Content of Ochani River in Ogoni, Rivers State, Nigeria

The Heavy metal Pollution Index (HPI), Metal Index (MI) and the Polycyclic Aromatic Hydrocarbon (PAH) contents of crude oil-polluted Ochani River in Ejamah-Ebubu community were investigated using physicochemical properties, Heavy Metal Analytic Method (AAS), GC-MS method and heavy metal pollution model. The results showed that Ochani River sampling station 2 (ORPS 2) had highest values of temperature, conductivity, turbidity, total solid (TS), total dissolved solid (TDS), Total Suspended Solid (TSS), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and nitrates with values as (32oC, 260 µScm-1, 42NTU, 460 mg/L, 526 mg/L, 400 mg/L, 15 mg/L, 10 mg/L, 25 mg/L and 7.5 mg/L respectively) compared to Ochani River sampling station 1 (ORPS 1) with values as (30oC, 200 µScm-1, 38NTU, 400 mg/L, 500 mg/L, 380 mg/L, 13 mg/L, 9.0 mg/L, 22 mg/L and 6.8mg/L respectively). However, these values of ORPS 1and 2 were higher than the unpolluted water sample (UWS) and WHO standard limits. Heavy metals obtained in Ochani River were rankedas Fe &gt; Cu &gt;Pb&gt; Zn &gt; Cr &gt; Cd &gt;As. The values obtained from crude oil polluted water samples were highest when compared with the values obtained of the UWS and WHO standard limit. The heavy metal pollution index of Ochani River was calculated as 402.32 mg/L which was higher compared with the critical pollution index value of 100. The metal index obtained was 49.88mg/L showing that the water quality classified to be seriously polluted. The Polycyclic Aromatic Hydrocarbon (PAH) components present in Ochani River include fluorene, naphthalene, dibenzyl(a,h)anthracene, benzo(k)fluoranthene and benzo(a)pyrene. However, these values of PAH components obtained were highest in ORPS 2 compared to ORPS 1. No PAH content was detected in UWS. However, the values of PAH obtained in both ORPS 1 and 2 were higher compared with WHO standard limit. In conclusion, Ochani River which is an important river used for irrigation and domestic activities by the populace in that community, is highly polluted with heavy metals and carcinogenic PAHs. We therefore recommend that Ochani River is unsafe for drinking, domestic and agricultural activities of the community where it is sited.

Evolution of PAHs in the mobile phase of low-rank coal during medium–low-temperature pyrolysis

The generation and release of polycyclic aromatic hydrocarbons (PAHs) during coal pyrolysis have been extensively studied, yet the evolution process of PAHs in the mobile phase is poorly understood. In this study, Yulin (YL) subbituminous coal and its solid products (YL350–700) obtained by pyrolysis at ∼350–700 °C were treated with dichloromethane, and the extracted PAHs were analyzed by gas chromatography and mass spectrometry. The total PAH concentration in the YL350–700 mobile phase was found to increase and then decrease with increasing pyrolysis temperature, and peak in the YL380 sample. The concentrations of alkylated PAHs were found to be the main contributors to the total PAH concentrations among the YL350–700 samples. YL coal was dominated by 4-ring PAHs, while YL350–700 samples were all dominated by 2-ring PAHs (naphthalene and alkylated naphthalenes). Variations in the proportion of 2-ring PAHs and the degree of naphthalene alkylation in YL350–700 indicated that alkylated naphthalenes were the main component of PAHs generated during YL coal pyrolysis at medium–low temperatures. This may suggest that the condensed aromatic units in the macromolecular structure of YL coal mainly consist of low-ring PAHs. Finally, an evolutionary process for PAHs in the mobile phase of YL subbituminous coal during pyrolysis at medium–low temperatures was proposed.

Laboratory investigation of pollutant emissions and PM2.5 toxicity of underground coal fires.

Widespread underground coal fires (UCFs) release large amounts of pollutants, thus leading to air pollution and health impacts. However, this topic has not been widely investigated, especially regarding the potential health hazards. We quantified the pollutant emissions and analyzed the physicochemical properties of UCF PM2.5 in a laboratory study of coal smoldering under a simulated UCF background. The emission factors of CO2, CO, and PM2.5 were 2489 ± 35, 122 ± 9, 12.90 ± 1.79 g/kg, respectively. UCF PM2.5 are carbonaceous particles with varied morphology and complex composition, including heavy metals, silica and polycyclic aromatic hydrocarbons (PAHs). The main PAHs components were those with 2-4 rings. Benzoapyrene (BaP) and indeno[1,2, 3-cd]pyrene (IcdP) were important contributors to the carcinogenesis of these PAHs. We quantitatively evaluate the toxicity of inhaled UCF PM2.5 using a nasal inhalation exposure system. The target organs of UCF PM2.5 are lungs, liver, and kidneys. UCF PM2.5 presented an enriched chemical composition and induced inflammation and oxidative stress, which together mediated multiple organ injury. Long-term PM2.5 metabolism is the main cause of persistent toxicity, which might lead to long-term chronic diseases. Therefore, local authorities should recognize the importance and effects of UCF emissions, especially PM2.5, to establish control and mitigation measures.

Aberrant mitochondrial DNA methylation and declined pulmonary function in a population with polycyclic aromatic hydrocarbon composition in particulate matter

Air pollution exposure has been found to be associated with epigenetic modification of the mitochondrial genome, which could subsequently induce adverse health outcomes. However, very limited studies exist regarding the association between fine particulate matter (PM2.5) exposure and pulmonary function at the molecular level of mitochondrial epigenetic changes. This study aimed to investigate the association of platelet mitochondrial DNA (mtDNA) methylation with occupational PM2.5 exposure and pulmonary function. First, 768 participants were occupationally exposed to polycyclic aromatic hydrocarbon (PAH)-enriched PM2.5 in a coke-oven plant in East China. The levels of PM2.5, PAH components bound to PM2.5, and urinary PAH metabolites in the workplace environment were measured as an internal dose, respectively. mtDNA methylation was measured by bisulfite pyrosequencing of two genes of ATP synthase (MT-ATP6 and MT-ATP8). Mediation analysis was conducted to evaluate the role of mtDNA methylation in pulmonary alteration induced by PAH. A decreasing trend of platelet mtDNA methylation was observed with increase in PM2.5 exposure across all participants. As an important PAH metabolite in urine, 1-hydroxypyrene (1-OHP) was significantly negatively associated with FEV1/FVC (Forced Expiratory Volume in 1s/Forced Vital Capacity) ratio. The participants with high serum folate levels (≥10 nmol/L) showed positive association between MT-ATP6 methylation and FEV1/FVC ratio. Mediation analysis suggested that MT-ATP6 methylation mediated the significant association of urinary 1-OHP with FEV1/FVC. Our findings suggested the methylation of platelet mitochondrial gene MT-ATP6 and FEV1/FVC to be negatively associated with PM exposure. Platelet mtDNA methylation acted as an intermediary between PAH exposure and lung function decline. The mitochondrial epigenetic regulation in platelets, in response to PM exposure, might be involved in subsequent progress of abnormal pulmonary function.

Aryl hydrocarbon receptor-kynurenine axis promotes oncogenic activity in BCP-ALL.

B-cell precursor acute lymphoblastic leukemia (BCP-ALL), the most common childhood cancer, originates from lymphoid precursor cells in bone marrow committed to the B-cell lineage. Environmental factors and genetic abnormalities disturb the normal maturation of these precursor cells, promoting the formation of leukemia cells and suppressing normal hematopoiesis. The underlying mechanisms of progression are unclear, but BCP-ALL incidence seems to be increasing in parallel with the adoption of modern lifestyles. This study hypothesized that air pollution and haze are risk factors for BCP-ALL progression. The current study revealed that indeno(1,2,3-cd)pyrene (IP), a major component of polycyclic aromatic hydrocarbons (PAHs) in air, promotes oncogenic activities (proliferation, transformation, and disease relapse) in vitro and in vivo. Mechanistically, IP treatment activated the aryl hydrocarbon receptor (AHR)-indoleamine-2,3-dioxygenase (IDOs) axis, thereby enhancing tryptophan metabolism and kynurenine (KYN) level and consequent promoting the KYN-AHR feedback loop. IP treatment decreased the time to disease relapse and increased the BCP-ALL cell count in an orthotopic xenograft mouse model. Additionally, in 50 clinical BCP-ALL samples, AHR and IDO were co-expressed in a disease-specific manner at mRNA and protein levels, while their mRNA levels showed a significant correlation with disease-free survival duration. These results indicated that PAH/IP exposure promotes BCP-ALL disease progression.

Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Water of an Abandoned Borrowed Pit with Wood-dust Deposit, Port Harcourt, Nigeria

The incidence of borrow pit pollution is a common phenomenon all over the world and Polycyclic aromatic hydrocarbons (PAHs) present in the environment are on the increase. Water samples from wood-dust effluent points at Egbelu, Port Harcourt were collected and analyzed for PAHs concentration. The analysis was achieved after extraction with Dichromethane and n-hexane in a Soxhlet extractor while Gas Chromatography mass spectrometry was used to separate and identify the components of PAHs in the water samples. The results obtained showed the presence of 2-3, 4 and 5-member ring priority PAHs from the borrow pit, while others were not detected from any of the locations examined. Different classifications showed that the mean concentration value for 2-3, 4 and 5 member rings were 0.132±0.00381, 0.235±0.00381, and 0.192±0.00436 mg/L respectively. In all, eight priority PAHs were detected (Benzo (a) Pyrene, Benzo (k) Fluoranthene, Indo (1,2,3, c-d) Pyrene, Dibenzo (a,h) Anthracene, Benzo(g,h,i) Naphthalene, Flourene and Anthracene. The Mean concentration of samples also showed Ao to be the highest in PAHs concentration while Bo is the lowest. Thus indicating the impact of wood dust on PAHs with only pyrogenic source of contamination. Authorities involved with administration, management and enforcement of contaminants and pollutants on dumping sites should channel their efforts to curb the incidence of outburst of PAHs pollution in the future and fishes from the same source be studied to show the levels of absorption.

Personal exposure to electrophilic compounds of fine particulate matter and the inflammatory response: The role of atmospheric transformation

Atmospheric oxidation can produce electrophilic compounds, altering the health effects induced by fine particulate matter (PM2.5); however, little is known about these electrophilic compounds or their health effects. Using electron capture negative ionization, we systematically detected 301 electrophilic compounds from personal PM2.5 samples in a panel study in urban Beijing. Most were oxygen-containing compounds with 3–17 double bond equivalents (DBE), suggesting the dominance of oxidized aromatic structures. Over 64% of the species, mostly outdoor-originated, were associated with inflammatory cytokines in both exhaled breath condensate and serum. Primary components of polycyclic aromatic hydrocarbons (PAHs) and high-DBE oxygenated PAHs, mainly from fossil fuel combustion, were positively associated with interleukin (IL)− 6, a cytokine related to oxidative homeostasis. Oxidized secondary species, particularly maleic and phthalic anhydrides, were negatively associated with IL-2/IL-8, which changed by − 3.8% to − 16.4% per one-fold increase in the abundance of the secondary source, indicating the immune disorders in response to the oxidized aerosols. Mediation analysis demonstrated the necessity of transformation products between atmospheric oxidation capacity and IL-2/IL-8 inhibition. This study provides new information on particulate electrophilic compounds and highlights the role of atmospheric chemistry in specific immune disorders.