High Polycyclic Aromatic Hydrocarbons Research Articles

Occurrence of polycyclic aromatic compounds in guarana (Paullinia cupana) seeds subjected to different drying processes

In this study, the levels of polycyclic aromatic compounds (PACs), such as polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (oxy-PAHs) were investigated in guarana seeds (Paullinia cupana) subjected to different drying methodologies. An innovative extraction method combined with a miniaturized dispersive solid-phase extraction cleanup procedure was developed for the determination of PACs concentration. Thirteen-eight guarana seed samples subjected to three different drying methodologies (sun drying, greenhouse drying, and alguidar furnace drying) were collected from different rural producers in the South Region of the State of Bahia, Brazil. Principal component analysis and diagnostic ratios were used to evaluate the correlation between samples and the PACs and the main sources of contamination. According to the results, the average concentration of PACs found in sun-dried, greenhouse-dried, and alguidar-dried ranged from 1.30 µg kg−1 (coronene) to 114 µg kg−1 (fluorene), from 0.48 µg kg−1 (dibenzo[a,h]anthracene) to 128 µg kg−1 (fluorene), and from 6.0 µg kg−1 (anthracene) to 422 µg kg−1 (phenanthrene). Oxy-PAHs, such as 1,4-NQ was detected predominantly in sun-dried and greenhouse-dried samples at concentrations ranging from 30.7 µg kg−1 to 83.9 µg kg−1. Low molecular weight PAHs, such as naphthalene, acenaphthylene, and fluorene were found in most of the samples independently of drying methodology. However, high molecular weight PAHs, including the carcinogenic benzo[a]pyrene was found predominately in alguidar-dried samples in concentrations higher than 20 µg kg−1.

Multimedia distribution of polycyclic aromatic hydrocarbons in the Wang Lake Wetland, China

The Wang Lake Wetland is a highly valued area that is protected due to its high biodiversity. The wetland has a complicated hydrological regime and is subject to frequent human disturbance. We hypothesize that fluctuating hydrology and human activities have varied contributions to the temporal and spatial variations of polycyclic aromatic hydrocarbons (PAHs) in the wetland. Soil (SS), sediment (SD), and water, to acquire dissolved phase (DP) and suspended particulate matter (SPM), samples were collected from eight locations during low- and high-flow periods to elucidate multimedia phase distribution and transport of PAHs. Following the onset of the rainy season, the concentration of SPM-associated PAHs increased significantly, while the DP PAHs remained stable. Individual PAH ratios showed that, although pyrogenic sources are common, petrogenic derived compounds are the main source of PAHs in the Wang Lake Wetland. During the high-flow period, the empirical values for logarithms of the organic carbon-normalized partition coefficients (log KOC) of individual PAH-congeners were lower than the corresponding field-observed log KOC values from the SPM-DP and SD-DP systems, reflecting the complexity in evaluating multi-phase PAH partitioning. During the high-flow period, temperature-driven changes may have changed the sediment from a sink to a source for some high molecular weight PAHs. It was determined that human activities governed the PAH loading in the low-flow period, whereas during high-flow conditions, increased rainfall, higher temperatures, and fishery activity are the main factors controlling PAH input to the Wang Lake Wetland.

Polycyclic Aromatic Hydrocarbons and Their Effects on the Occurrence of Chronic Obstructive Pulmonary Disease (COPD): A Review

Background: Polycyclic aromatic hydrocarbons (PAHs) are among the most important compounds that cause adverse health outcomes in humans, such as poor lung function, bronchitis, asthma, shortness of breath, circulatory disorders, lung cancer, cardiovascular diseases, and mortality. Objectives: This review aims to investigate the effects of PAHs on the occurrence of chronic obstructive pulmonary disease (COPD). Methods: A narrative review of the literature was done from 1979 to 2021 in various databases: Science Direct, PubMed, Web of Science, Springer, and Google Scholar. We found 76 and 14 articles by searching the databases and other sources, respectively. Twelve articles were included after screening. The literature indicates the significant adverse effect of PAHs on the occurrence of COPD. Results: Heavy industries (oil, steel, gas, and petroleum) are the primary sources of PAHs. Polycyclic aromatic hydrocarbons induce respiratory diseases, as they are destructive to the lung, leading to COPD. Sex, age, nutritional status, health, duration of exposure to PAHs, and body response to the pollutants affect the complications. Conclusions: High PAH levels can increase the risk of COPD, respiratory diseases, and incremental lifetime cancer risk (ILCR).

The Effects of Fat Content and Cooking Procedures on the PAH Content of Beef Doner Kebabs

This study aimed to determine the effect of different fat contents (low-fat/LF or high-fat/HF), cooking methods (gas, charcoal, or electric), and various degrees of doneness (medium and well-done) on polycyclic aromatic hydrocarbon (PAH) formation in beef doner kebabs. Liquid– liquid extraction and solid- phase extraction (SPE) were used to determine the PAH levels in doner kebabs. In addition, PAHs were determined and identified via HPLC/UV–Vis method. Among the 16 PAHs analyzed, only seven common PAHs were detected in doner samples (Benzo[c]fluorene (BcFE), Cyclopenta[cd]pyrene (CPcdP), Benzo[a]pyrene (B[a]P), Benzo[a]anthracene (B[a]A), Chrysene (Chry), Benzo [ghi] perylene (B[ghi]P) and Dibenzo(a,h)anthracene (DB[a,h]A). The two most abundant PAHs were BaA and CPcdP, with concentrations ranging from 43.05-143.10 μg/kg and 13.90-80.44 μg/kg, respectively. BaP, one of the main indicators for the presence of PAHs in food, was observed in all samples concentrations ranging from nd-7.38 μg/kg. Other PAHs were found in particularly well-done and high-fat doner samples. Additionally, the total PAH4 and total PAH8 concentrations were in the range of 43.05-150.40 μg/kg and 43.05-198.10 μg/kg, respectively. The results revealed that in both types of doner samples (low-fat/LF or high-fat/HF), the highest PAH concentration was noted when the charcoal cooking method was used, while the lowest PAH concentration was detected when the electric cooking method was employed. In addition, PAH compounds were found to be more abundant in high-fat doner samples (HF) than in low-fat groups (LF) (p < 0.05). In conclusion, the diversity and amount of each PAH compound in beef doner kebab samples varied depending on doneness degree, doner kebab type (low- fat/LF or high- fat/HF), and cooking methods (p < 0.05).

Halophilic Martelella sp. AD-3 enhanced phenanthrene degradation in a bioaugmented activated sludge system through syntrophic interaction

Polycyclic aromatic hydrocarbons (PAHs) are a group of common recalcitrant pollutant in industrial saline wastewater that raised significant concerns, whereas traditional activated sludge (AS) has limited tolerance to high salinity and PAHs toxicity, restricting its capacity to degrade PAHs. It is therefore urgent to develop a bioaugmented sludge (BS) system to aid in the effective degradation of these types of compounds under saline condition. In this study, a novel bioaugmentation strategy was developed by using halophilic Martelella sp. AD-3 for effectively augmented phenanthrene (PHE) degradation under 3% salinity. It was found that a 0.5∼1.5% (w/w) ratio of strain AD-3 to activated sludge was optimal for achieving high PHE degradation activity of the BS system with degradation rates reaching 2.2 mg⋅gVSS−1⋅h−1, nearly 25 times that of the AS system. Although 1-hydroxy-2-naphthoic acid (1H2N) was accumulated obviously, the mineralization of PHE was more complete in the BS system. Reads-based metagenomic coupled metatranscriptomic analysis revealed that the expression values of ndoB, encoding a dioxygenase associated with PHE ring-cleavage, was 5600-fold higher in the BS system than in the AS system. Metagenome assembly showed the members of the Corynebacterium and Alcaligenes genera were abundant in the strain AD-3 bioaugmented BS system with expression of 10.3±1.8% and 1.9±0.26%, respectively. Moreover, phdI and nahG accused for metabolism of 1H2N have been annotated in both above two genera. Degradation assays of intermediates of PHE confirmed that the activated sludge actually possessed considerable degradation capacity for downstream intermediates of PHE including 1H2N. The degradation capacity ratio of 1H2N to PHE was 87% in BS system, while it was 26% in strain AD-3. These results indicated that strain AD-3 contributed mainly in transforming PHE to 1H2N in BS system, while species in activated sludge utilized 1H2N as substrate to grow, thus establishing a syntrophic interaction with strain AD-3 and achieving the complete mineralization of PHE. Long-term continuous experiment confirmed a stable PHE removal efficiency of 93% and few 1H2N accumulation in BS SBR system. This study demonstrated an effective bioaugmented strategy for the bioremediation of saline wastewater containing PAHs.

Levels of Polycyclic Aromatic Hydrocarbons (PAHs) in muscles of commercial fishes from Iraqi waters

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured in the muscles of eight kind of fishes from National Iraqi Waters, Five marine species viz., Euryglossa orientalis, Otolithes ruber, Lethvinus nebulosus, Epinephelus coioides and Johnieops sina which were collected from Iraqi marine waters, and three species viz, Cyprinus carpio, Carasobarbus luteus and Plantiliza abu which were collected from Shatt Al-Arab river fresh water. All fishes were collected during spring and autumn seasons within the year 2015. Recorded total polycyclic aromatic hydrocarbons in fish species from Iraqi national waters were varied between 0.054 and 155.44 ng/g, while for individual fishes: Anthracene recorded the highest values varied between 17.629 and 155.44 ng/g dry wet. Lower total PAHs value recorded was 197.54 ng/g dry wet. in O. ruber and higher total PAHs value recorded was 381.415 ng/g dry wet. in E. coioides, followed by P. abu which recorded higher total PAHs value of 275.938 ng/g dry wet. Large differences in the values of PAHs recorded during autumn 2015 were achieved which were lower than those recorded during spring. According to the ratios between low and high molecular weight PAHs, there are two sources for PAHs in the investigated fishes, the first was pyrogenic which was appeared in the fishes L. nebulosus and E. orientalis only for 0.355 and 0.274 ng/g respectively during spring 2015 and second anthrapogenic which appeared in all fishes except L. nebulosus and E. orientalis. Therefore during spring season the dominated source was the anthropogenic one. For the results of Autumn season, the ratios indicate predominant the values which were lower than 1 for mostly all studied fishes except that for E. orientalis which was equal to 1.040 indicating that most of the PAHs were from anthropogenic source. Although, concentration of petroleum hydrocarbons (PAHs) in fishes from national Iraqi waters along North West Arabian Gulf were recorded in most studied fishes, but they markedly higher than that in the background and previously reported studies in the same and nearby areas. From a public health point, petroleum hydrocarbon residue levels, especially the carcinogenic ones, in all fish samples analyzed in this study are considerably lower than the hazardous levels and doesn’t exert any health effect upon human being upon consumption.

Transformation mechanism of polycyclic aromatic hydrocarbons and hydrogen production during the gasification of coking sludge in supercritical water

In this study, the characteristic of hydrogen production and polycyclic aromatic hydrocarbons (PAHs) transformation during supercritical water gasification (SCWG) of coking sludge (400 °C - 450 °C, 1 min–30 min) were explored. The total gas yield was between 0.62 mol/kg OM and 1.05 mol/kg OM (on dry basis), and the proportion of CH4 and H2 was only between 5.41% and 6.44%. PAH content were increased from 194.92 mg/kg to 326.04 mg/kg, and mainly high molecular weight PAHs, which were formed from the Diels-Adler reaction of single aromatic hydrocarbon and the addition reaction of low molecular weight PAHs. High reaction temperature favored more active PAH formation than reaction time. The possible control methods for PAH formation during SCWG of coking sludge was proposed. H2O2 and KOH addition effectively reduce PAHs amount in solid residues by 46.67% and 38.33%, and KOH performed positive effect on hydrogen production. The work revealed that the inhibition of PAHs and hydrogen production were achieved from SCWG of coking sludge with KOH addition.

Occurrence of polycyclic aromatic compounds and interdomain microbial communities in oilfield soils

Soil polycyclic aromatic compound (PAC) pollution as a result of petroleum exploitation has caused serious environmental problems. The unclear assembly and functional patterns of microorganisms in oilfield soils limits the understanding of microbial mechanisms for PAC elimination and health risk reduction. This study investigated the polycyclic aromatic hydrocarbons (PAHs) and substituted PAHs (SPAHs) occurrence, and their impact on the bacteria-archaea-fungi community diversity, co-occurrence network and functionality in the soil of an abandoned oilfield. The results showed that the PAC content in the oilfield ranged from 3429.03 μg kg−1 to 6070.89 μg kg−1, and risk assessment results suggested a potential cancer risk to children and adults. High molecular weight PAHs (98.9%) and SPAHs (1.0%) contributed to 99.9% of the toxic equivalent concentration. For microbial analysis, the abundantly detected degraders and unigenes indicated the microbial potential to mitigate pollutants and reduce health risks. Microbial abundance and diversity were found to be negatively correlated with health risk. The co-occurrence network analysis revealed nonrandom assembly patterns of the interdomain microbial communities, and species in the network exhibited strong positive connections (59%). The network demonstrated strong ecological linkages and was divided into five smaller coherent modules, in which the functional microbes were mainly involved in organic substance and mineral component degradation, biological electron transfer and nutrient cycle processes. The keystone species for maintaining microbial ecological functions included Marinobacter of bacteria and Neocosmospora of fungi. Additionally, benzo [g,h,i]pyrene, dibenz [a,h]anthracene, indeno [1,2,3-cd]perylene and total phosphorus were the key environmental factors driving the assembly and functional patterns of microbial communities under pollution stress. This work improves the knowledge of the functional pattern and environmental adaptation mechanisms of interdomain microbes, and provides valuable guidance for the further bioremediation of PAC-contaminated soils in oilfields.

Dynamics and Mass Balance of Polycyclic Aromatic Hydrocarbons in and Around the Seto Inland Sea, Japan

Polycyclic aromatic hydrocarbons (PAHs) were analyzed to elucidate the distribution, ecological risk, pathways, and fluxes of these pollutants in and around the Seto Inland Sea, an industrialized coastal region of Japan. High molecular weight PAHs (5-6 rings) were primarily found in regions close to the bay estuaries, and their proportions decreased at distances further from the estuaries (offshore areas), where low molecular weight PAHs (2-4 rings) were more ubiquitous. Screening-level risk assessments revealed that the PAHs found in the sediments should have no adverse effects on benthic communities. A mass balance for PAHs in the Seto Inland Sea, calculated based on data collected in the field and published literature findings, showed the PAH flux into the Seto Inland Sea from atmospheric deposition were ca. 6 times higher than that from riverine inflows. Comparison of the amount of the PAH mass flux between the Seto Inland Sea and the sea of the Europe and Asian countries indicated that the Seto Inland Sea is less polluted than the Gulf of Lion, the Mediterranean Sea, and the Bohai Sea, China and more polluted than the Yellow Sea. This paper is the first to determine the fluxes of PAHs in the coastal region of Japan.

PM2.5‐Bound Polycyclic Aromatic Hydrocarbons (PAHs), Nitrated PAHs (NPAHs) and Oxygenated PAHs (OPAHs) in Typical Traffic‐Related Receptor Environments

AbstractPM2.5‐bound polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs (NPAHs) and oxygenated PAHs (OPAHs) around roadside, port and airport areas were investigated to evaluate the impacts of vehicle, ship and aviation emissions on PAHs and their derivatives in relevant receptor environments. The PAHs concentrations in fuels increased in the following order: jet fuel &lt; heavy fuel oil for vessel &lt; automobile diesel fuel. However, the average mass ratio concentrations of PM2.5‐bound PAHs in roadside, port and airport areas were 42.9, 158.7 and 260.4 μg/g, respectively. The low PAHs concentrations in fuel were relevant to the high PAHs emissions. The composition of the molecular species showed that 5‐ and 6‐rings PAHs were dominated in roadside area, while 3‐ and 4‐rings PAHs were major proportions in port and airport areas. The average mass ratio concentrations of PM2.5‐bound NPAHs and OPAHs concentrations in roadside, port and airport areas were 23.5 and 115.2, 4.8 and 39.9, and 26.4 and 284.2 μg/g, respectively. The different variation tendencies between PAHs and their derivates, dominant individual NPAHs, diagnostic ratios of NPAH isomers and principal component analysis revealed that primary emission was the major contributor to NPAHs and OPAHs in three receptor environments, and secondary formation played non‐negligible roles in NPAHs formation in roadside and airport areas. In addition, 9‐nitroanthracene (9‐NAnt) and anthraquinone (ATQ) were found to be the indicatory compounds for traffic emission. Taken together, these results may provide a basic information for assessing the impact of traffic emission sources on PAC emissions to the related receptor environment.

Current and Future Trends of Low and High Molecular Weight Polycyclic Aromatic Hydrocarbons in Surface Water and Sediments of China: Insights from Their Long-Term Relationships between Concentrations and Emissions.

In this study, we analyzed the temporal trend of polycyclic aromatic hydrocarbons (PAHs) in China using data reported over the past 20 years. We found that the total concentrations of low molecular weight PAHs (CΣLPAHs) in surface water and sediments were positively correlated with their total emissions (EΣLPAHs), which increased between 2000 and 2008, then decreased until 2017. Additionally, the total concentrations of high molecular weight PAHs (C∑HPAHs) in surface water and sediments were positively correlated with their total emissions (EΣHPAHs), which increased significantly from 2000 to 2014 and then plateaued. Two future scenarios were assessed to explore C∑LPAHs and C∑HPAHs in surface water and sediments. PAH emissions were reduced by technological improvement in 2030 for coal consumption in Scenario 1 and for control of biomass burning in Scenario 2. Scenario 1 was more efficient than Scenario 2 in reducing C∑HPAHs in the surface water and sediments of China for the areas where CΣHPAHs in surface water exceeded the annual average standard (i.e., 30 ng L-1), with reductions of 38 and 24% in Scenarios 1 and 2, respectively. The observed relationships in this study can provide tools for emission reduction policies in the future.

Oxidative status of planarians is differently affected by PAHs: 3-5 Benzene ring compounds

Planarians are promising model animals and are increasing in importance for ecotoxicological studies. However, there is scarce to no information regarding polycyclic aromatic hydrocarbons (PAHs) specific toxicity towards planarians at the biochemical level. We aimed to uncover how vital physiological functions, such as, neurophysiology, detoxification and oxidative stress status, and cellular energy allocation are affected on the freshwater planarian Girardia tigrina by low and high molecular weight PAHs – phenanthrene, pyrene and benzo[a]pyrene (B[a]P). Phenanthrene affected planarian antioxidant defences and detoxification, increasing glutathione levels and activity of glutathione-S-transferase (GST), the latter in a dose-dependent way (from 75 to 300 µg L−1). Phenanthrene also decreased carbohydrates in planarians exposed to 150 and 300 µg L−1. Pyrene caused higher oxygen consumption and decreased energy budget in planarians exposed to 75 and 150 µg L−1. B[a]P exposure decreased G. tigrina GST activity in a dose-dependent way. Lower lipid peroxidation levels were measured in planarians exposed to 2.5 and 75 µg L−1 of pyrene and at 37.5, 75 and 150 µg L−1 of B[a]P. The present data indicate that each of these PAHs seems to elicit distinct biochemical responses in planarians, possibly pointing to different biochemical interactions and/or metabolisation of each compound, with B[a]P causing the most severe effects.

Drinking water treatment residue recycled to synchronously control the pollution of polycyclic aromatic hydrocarbons and phosphorus in sediment from aquatic ecosystems

Great efforts have long been made to control sediment pollution from persistent organic pollutants and phosphorus for aquatic ecosystem restoration. This study proposed a novel recycling of drinking water treatment residue (DWTR) to synchronously control sediment polycyclic aromatic hydrocarbons (PAHs) and phosphorus pollution based on a 350-day incubation test. The results suggested that DWTR addition reduced approximately 88%− 96% of potential bioavailable PAHs and 76% of mobile phosphorus in sediment. The dominant mechanisms for both reductions by DWTR were immobilization, mainly through increasing sediment amorphous aluminum and iron. The tendency of enhanced PAHs degradation by DWTR was also observed, especially for high molecular weight PAHs (e.g., chrysene, indeno(1, 2, 3-cd)pyrene, and benzo(g, hi)perylene), which decreased by approximately 21.1%− 22.0% of the total. Additionally, accompanying a clear increase in the connections of microbial cooccurrence networks, the variations in bioavailable PAHs, amorphous aluminum and iron, and other properties (e.g., pH, nitrogen, and organic matter) significantly (p < 0.01) enhanced Flavobacterium enrichment, although the enrichment of many other microbes potentially related to PAHs degradation (e.g., C1-B045) decreased after DWTR addition. Therefore, DWTR could promote the construction of a “PAHs immobilization with microbial augmentation” system while immobilizing phosphorus in sediment, indicating the high feasibility of controlling multiple sediment pollution.

Exposure to atmospheric particle-bound Polycyclic Aromatic Hydrocarbons in the vicinity of two cement plants in Córdoba, Argentina

Total Suspended Particle (TSP) samples (n = 110) were collected daily from two sites located in the vicinity of a large industrial complex dedicated to cement manufacturing in Córdoba province, Argentina. The levels of 14 out of the 16 target Polycyclic Aromatic Hydrocarbons (PAHs) were determined. The results obtained show the contribution of this industrial activity to local dust and particle-bound PAH levels, affecting two of the closest neighborhoods in the area (Yocsina and Malagueño). Individual PAHs ranged from 0.01 to 6.81 ng m−3, and mean concentrations of Σ14PAHs in Yocsina and Malagueño were 6.97 and 18.13 ng m−3, respectively. Of these PAHs, Naphthalene (Naph), Fluorene (Flu) and Phenanthrene (Phen) were the most abundant. Source apportionment analysis revealed that Phen, Naph and Acenaphthene (Ace) originated from the cement plant emissions, whereas Benzo[a]pyrene (BaP), Dibenzo[a,h]anthracene (DahA) and Anthracene (Anth) came from vehicle emissions and biomass combustion. A multiple linear regression model revealed that 56% of the variation in the total PAH concentrations may be explained by temperature, wind speed, wind direction and TSP. To assess PAH dispersion, TSP stack emissions from both cement plants were estimated using AERMOD, the steady-state plume model. The results revealed the local impact of stack emissions surrounding Yocsina neighborhood. In contrast, the main emission sources of the high PAH levels at the Malagueño sampling site were vehicular traffic, house heating and a concrete products factory, rather than the cement stacks. The lifetime lung cancer risk at the Malagueño sampling site exceeded the permissible standards established by the United States Environmental Protection Agency and the World Health Organization, thereby representing a majorenvironmental risk tohuman health.

Synthesis and evaluation of recoverable activated carbon/Fe3O4 composites for removal of polycyclic aromatic hydrocarbons from aqueous solution

Three different synthesis methods were employed to prepare magnetic powder and granular activated carbons (MPAC and MGAC) as recoverable adsorbents to remove polycyclic aromatic hydrocarbons (PAHs) from aqueous solutions. The MPAC and MGAC composites were characterized by XRD, and the XRD patterns confirmed the presence of Fe 3 O 4 particles with cubic crystal structure on the adsorbents surface. FE-SEM images showed that the magnetic composites had spherical morphologies, with clusters of iron oxide nanoparticles formed in the ACs pores and distributed evenly on their surface. FTIR spectra of the PAH-loaded adsorbents revealed that the analytes were attached to the surfaces of MPACs and MGACs by π - π and H- π interactions formed between the PAHs and functional groups of the adsorbents. All the synthesized magnetic ACs were very effective in removing PAH compounds from aqueous solution with removal percentages between 87.2% to 99.3%. The precipitation method of magnetization resulted in the highest PAHs removal efficiency (99.3%) using PAC as the base AC, while the co-precipitation method of magnetization provided the highest PAHs removal efficiency (98.3%) using GAC as the base AC. The PAHs desorption tests indicated that low molecular weight PAHs were more easily desorbed from the magnetic ACs ranging from 38.1 to 60.1%, compared with high molecular PAHs ranging from 23.4 to 57.2%. This shows that the increase in the number of PAH rings would lead to the formation of more covalent bonds between the adsorbate and the adsorbent. • Six types of magnetic activated carbon particles were successfully synthesized and characterized. • All the synthesized magnetic adsorbents were able to strongly remove PAHs from the aqueous solutions. • The adsorption results indicated that the PAHs have a strong affinity to the surface of the magnetic activated carbons. • All the magnetic activated carbons could be rapidly and efficiently separated from the solutions by a magnetic field. • Desorption of five- and six-ring PAHs from the magnetic activated carbons were lower than three- and four-ring PAHs.

Spatial clustering and source-specific risk of combined pollutants in soils from an industrial area in Shanxi Province, China

Heavy metal (loid)s (HMs) and polycyclic aromatic hydrocarbons (PAHs) in soils from a typical industrial county of Shanxi were synchronously measured to determine the spatial clustering of combined HMs and PAHs pollution, and the resulting source-specific health risks. The spatial interaction of HMs and PAHs was determined by the Moran's I index, and a bivariate local indicators of spatial association (LISA) analysis showed that the high HMs-high PAHs clusters were mainly distributed in Fencheng and Xijia towns, as well as the main urban areas of Xiangfen County. The spatial clusters of high naphthalene (Nap)-high HMs were more obvious than those of high benzo(a)pyrene (Bap)-high HMs. Based on positive matrix factorization (PMF), four sources were identified for both HMs and PAHs, with coal consumption and industrial emission identified as common sources of both pollutants. The source-oriented health risk was determined using an improved health risk assessment model. The cancer risk from the combined pollution industrial emissions was relatively serious for both adults and children, with the risk value exceeding 10−6. Therefore, special attention should be paid to emission control. Based on spatial clustering and source-specific health risk assessment, the largest risk areas and pollutant sources were in the main urban areas of Fencheng and Xijia towns. The spatial interaction patterns and source-specific HMs and PAHs pollution concentrations provide a basis for effective pollution management and control. Finally, a systematic framework for reference was proposed for risk area identification and analysis of the source-oriented health risks of combined HMs and PAHs pollution.

Plant contribution to the remediation of PAH-contaminated soil of Dagang Oilfield by Fire Phoenix.

Pot experiments were conducted to evaluate plant contribution during remediation of the polycyclic aromatic hydrocarbons (PAH)-contaminated soil of Dagang Oilfield by Fire Phoenix (a mixture of Festuca L.). The results showed that Fire Phoenix could grow in soil contaminated by high and low concentrations of PAHs. After being planted for 150days, the total removal rate of six PAHs in the high and low PAH concentrations was 80.36% and 79.79%, significantly higher than the 58.79% and 53.29% of the unplanted control group, respectively. Thus, Fire Phoenix can effectively repair the soil contaminated by different concentrations of PAHs. In high concentrations of PAHs, the results indicated a positive linear relationship between PAH absorption in tissues of Fire Phoenix and the growth time in the early stage. In contrast, the contents of PAHs were just slightly increased in the late period of plant growth. The main factor for the dissipation of PAHs was plant-promoted biodegradation (99.04%-99.93%), suggesting a low contribution of PAH uptake and transformation (0.07%-0.96%). The results revealed that Fire Phoenix did not remove the PAHs in the soil by accumulation but promoted PAH dissipation in the soil by stimulating the microbial metabolism in the rhizosphere.

HEALTH RISK ASSESSMENT OF POLYCYCLIC AROMATIC HYDROCARBONS IN BOBO CROAKER (Pseudotolithus elongatus) FROM THE BONNY RIVER, RIVERS STATE, NIGERIA

The sudden death of thousands of Pseudotolithus elongatus in the first quarter of the year 2020 was an indication of elevated effluent contamination. The study was aimed at evaluating the human health risk of human exposure Polycyclic Aromatic Hydrocarbon (PAH)s to P. elongatus exposed to contaminants in Bonny River. Thirty-six P. elongatus and eighteen controls were sampled from the Bonny River in two seasons, (Wet season and Dry season) and analyzed for PAHs using Gas Chromatography - Flame Ionization Detector (GC-FID). Risk assessment of PAHs for the Dietary Daily Intake (DDI), carcinogenic potencies[(B(A)Pteq)], PAH4 index, Carcinogenic toxic equivalents (TEQ) and Excess Cancer Risk Index (ECR) was evaluated. DDI of PAHs indicates 1.4E-03 in Chrysene and Indeno (1,2,3) pyrene for wet season, and 1.1E-03 during the dry season. PAH4 revealed 0.065mg/kg in wet season and 0.23 mg/kg in dry season which are significantly above EU standard of 0.03mg/kg. B(A)Pteq in Dibenzo (a,h)anthracene (6.2E-02 and 0.22) were also higher than the EU standard. TEQs values were 0.23 mg/kg and 6.5E-02 were above the SV of 5.55E-03mg/kg which indicates potential toxicity. Result of the present studies indicates that there could be high potential PAHs human health risk associated with the consumption of Bobo Croaker (Pseudotolithus elongatus) from Bonny River.

Degradation profile and dioxygenase activity of Carnobacterium gallinarum (mt350233) and Enterococcus faecalis (mt345788) isolated from landfill soil in Benin City

Landfill is a potential microbial hub of hydrocarbon (HC) degrading bacterial population owing to nutrient availability and continuous enrichment by organic materials. The degradation and dioxygenase activity of Carnobacterium gallinarum and Enterococcus faecalis isolated from landfill soil in Benin City was investigated. Soil samples were collected from a Government approved landfill in Benin City at a depth of 0 to 10 cm. Standard microbiological and molecular methods were followed for the isolation and characterization of bacterial population. Bacterial isolates were standardized for degradation using spectrophotometer optical density (OD) 0.08 at 600 nm (equivalent to 1×108cfu/ml). The gas chromatography with flame ionization detector (GC-FID) method was used to determine the total petroleum hydrocarbon (TPH) of waste engine oil (WEO) containing samples. The spectrophotometric methods were used for the assay of catechol 1,2-dioxygenase (C12O) and catechol 2,3-dioxygenase (C23O) activity. The result of the 16S rRNA analyses of the bacterial isolates confirmed the identity of Carnobacterium gallinarum as 98.71 % and Enterococcus faecalis as 100 %. The degradation profile of Carnobacterium gallinarum and Enterococcus faecalis at varied concentrations (20, 40, 60, 80 and 100 mg/L) of WEO showed significant decline in optical density (OD) values from day 1 to day 7. The decline in OD is an indication of utilization of Polycyclic Aromatic Hydrocarbons (PAHs) present in the WEO. The result of the gas Chromatography with Flame Ionization Detector (GC-FID analyses) of degraded WEO containing samples revealed the absence of low molecular weight and high molecular weight PAHs after the 7-days degradation study. The presence of HC degrading enzyme in the bacterial isolates was confirmed by the production of C12O and C23O as a result of the formation of cis, cis muconic acid and 2-hydroxymuconic semi-aldehyde respectively. This study revealed that the landfill soil is a potential natural microcosm for WEO degrading bacteria and possesses biologically active HC degrading bacteria population such as Carnobacterium gallinarum and Enterococcus faecalis.

Non-equilibrium influence on G/P partitioning of PAHs: Evidence from the diurnal and nocturnal variation

Gas/particle (G/P) partitioning is an important behavior for the atmospheric transport of polycyclic aromatic hydrocarbons (PAHs). In this study, paired daytime and nighttime air samples were collected for one year in order to study the diurnal and nocturnal variations of concentration and G/P partitioning of PAHs. Higher PAHs concentrations in total phase were observed in nighttime. The geomean (GM) concentrations of Σ15PAHs in total phase were 69.6 and 52.8 ng/m3 in nighttime and daytime, respectively. More obviously diurnal and nocturnal variations were observed in non-heating season, with the GM ratios of Σ15PAHs in nighttime to daytime of 1.65 and 1.06 in non-heating season and heating season, respectively. The results could be attributed to emission sources and meteorological conditions. The values of particulate phase fraction (ϕP) and G/P partitioning quotient (log KP) were used to quantify the phase distribution of PAHs. For most high molecular weight PAHs, the values of ϕP and log KP in nighttime were higher than those in daytime, which could be mainly attributed to the lower temperature in nighttime. However, for the three light molecular weight PAHs (Acy, Ace and Flu), higher values of ϕP and log KP were observed in daytime. The regression of log KP against log KOA for the three PAHs in daytime differed from those in nighttime. The chemical losses of PAHs in different phases might be responsible for the result. These findings suggested that the chemical loss of PAHs in gas phase should be considered for the G/P partitioning process.