Release Of Polycyclic Aromatic Hydrocarbons Research Articles

A multigenerational study can detect the evolutionary response to BaP exposure in the non-biting freshwater midge Chironomus riparius

The release of polycyclic aromatic hydrocarbons (PAHs) into the environment is posing a threat to ecosystems and human health. Benzo(a)pyrene (BaP) is considered a biomarker of PAH exposure and is classified as a Group 1 carcinogen. However, it was not known whether BaP is mutagenic, i.e. induces inherited germline mutations. In this study, we used a recently established method, which combines short-term mutation accumulation lines (MAL) with whole genome sequencing (WGS) to assess mutagenicity in the non-biting midge Chironomus riparius. The mutagenicity analysis was supplemented by an evaluation of the development of population fitness in three successive generations in the case of chronic exposure to BaP at a high concentration (100 μg/L). In addition, the level of ROS-induced oxidative stress was examined in vivo. Exposure to the higher BaP concentration led to an increase in germline mutations relative to the control, while the lower concentration showed no mentionable effect. Against expectations, BaP exposure decreased ROS-level compared to the control and is thus probably not responsible for the increased mutation rate. Likewise, the higher BaP concentration decreased fitness measured as population growth rate per day (PGR) significantly over all generations, without signs of rapid evolutionary adaptations. Our results thus highlighted that high BaP exposure may influence the evolutionary trajectory of organisms.

The effect of bioturbation on the release behavior of polycyclic aromatic hydrocarbons from sediments: A sediment–seawater microcosm experiment combined with a fugacity model

The effects of two benthonic species, Perinereis aibuhitensis and Matuta planipes Fabricius, on the release of polycyclic aromatic hydrocarbons (PAHs) from sediments were investigated using a sediment–seawater microcosm. A Level IV fugacity model was used to simulate the behavior and fate of PAHs in the environment. This study revealed that both benthos significantly influenced the release of PAHs, and Matuta planipes Fabricius had a stronger disturbance effect than another. The final concentrations of Matuta planipes Fabricius group, Perinereis aibuhitensis group and the control group in the seawater phase reached 10.8, 9.94 and 7.90 μg/L, respectively. There were certain differences in the behaviour of the two benthonic species. Matuta planipes Fabricius caused more sediment resuspension, while Perinereis aibuhitensis increased the total organic carbon (TOC) content in the environment. The vertical concentration distribution of sediment indicated that vertical mixing was slightly stronger in the Matuta planipes Fabricius group than that in the Perinereis aibuhitensis group. The fugacity model effectively simulated the release behavior of PAHs, providing insight into PAH transport and distribution. The results demonstrated that bioturbation could promote the release of PAHs from seawater. The amount of PAHs released was significantly correlated with the biological habits of the benthos.

Characterization of persistent organic contaminants in the atmosphere of Gadani's ship breaking yards and its surrounding: Implications for sustainable ship recycling practices

Gadani is internationally renowned for its extensive ship-breaking operations, positioning it as one of the globe's primary ship-breaking hubs. A comprehensive study was conducted to evaluate the presence of organic contaminants in the air within Gadani, encompassing the areas surrounding ship-breaking facilities, proximate residential settlements, and adjacent roadways. Passive air samplers were employed to collect a total of 30 air samples. The analytical results unveiled a notably elevated concentration of specific organic compounds, with a pronounced prevalence of polycyclic aromatic hydrocarbons (PAHs), short-chain chlorinated paraffins (SCCPs), and polychlorinated biphenyls (PCBs) at the ship-breaking yard. Notably, dichlorodiphenyltrichloroethanes (DDTs) and DDE were detected at substantially lower levels. In particular, sites in close proximity to ship-breaking activities exhibited elevated concentrations of PCBs (Σ7PCB 0.065429 to 7.345714 ng/sample), PAHs (Σ8PAH 2.44 to 134.23 ng/sample), and SCCPs (0.18 to 25.6 ng/sample). Conversely, DDTs and DDE demonstrated higher concentrations near residential settlements. The evaluation of Molecular Diagnostic Ratios for PAHs revealed anthracene/anthracene + phenanthrene ratios of 0.88, 0.69, and 0.5 for ship-breaking areas, roadside locations, and community surroundings, respectively. Furthermore, the benz[a]anthracene/benz-[a]anthracene + chrysene molecular ratios were measured at 0.77 (ship-breaking sites), 0.82 (roadside), and 0.83 (community), respectively. The molecular ratio of fluoranthene/fluoranthene + pyrene at ship-breaking sites was 0.23, while roadside and community ratios were 0.36 and 0.89, respectively. These findings underscore the significant contribution of ship-recycling activities to the atmospheric release of SCCPs, PCBs, and PAHs, emphasizing the global imperative for responsible ship recycling practices.

Polycyclic Aromatic Hydrocarbons (PAHs) in aquatic ecosystem exposed to the 2020 Baghjan oil spill in upper Assam, India: Short-term toxicity and ecological risk assessment.

This study focuses on the short-term contamination and associated risks arising from the release of Polycyclic Aromatic Hydrocarbons (PAHs) due to the 2020 Baghjan oil blowout in upper Assam, India. Shortly after the Baghjan oil blowout, samples were collected from water, sediment, and fish species and examined for PAHs contents. The results of the analysis revealed ΣPAHs concentrations ranged between 0.21-691.31 μg L-1 (water); 37.6-395.8 μg Kg-1 (sediment); 104.3-7829.6 μg Kg-1 (fish). The prevalence of 3-4 ring low molecular weight PAHs compounds in water (87.17%), sediment (100%), and fish samples (93.17%) validate the petrogenic source of origin (oil spill). The geographic vicinity of the oil blowout is rich in wildlife; thus, leading to a significant mass mortality of several eco-sensitive species like fish, plants, microbes, reptiles, amphibians, birds and mammals including the Gangetic River dolphin. The initial ecological risk assessment suggested moderate to high-risk values (RQ >1) of majority PAHs concerning fish, daphnia, and algae species. This study highlights the need for recognizing the potential for short-term exposure to local species. To safeguard local ecosystems from potential future environmental disasters, it is imperative for the government to adopt a precautionary strategy.

Concurrent assessment of diffusive and advective PAH movement strongly affected by temporal and spatial changes

Chemical movement influences exposure, remediation and interventions. Understanding chemical movement in addition to chemical concentrations at contaminated sites is critical to informed decision making. Using seepage meters and passive sampling devices we assessed both diffusive and advective flux of bioavailable polycyclic aromatic hydrocarbons (PAHs) at three time points, across two seasons, at a former creosote site in St. Helens, Oregon, United States. To our knowledge, this is the first time both diffusive and advective fluxes have been measured simultaneously at a contaminated site. Concentrations of 39 parent PAHs were determined by gas chromatography triple quadrupole mass spectrometry. Across both seasons and all sites, diffusive flux of PAHs was up to three orders of magnitude larger than advective flux. Release of PAHs from sediments and water were identified, likely from legacy contamination, as well as deposition from the air into the site from contemporary and other sources. The majority of PAH movement was comprised of three and four ring PAHs. Chemical movement on the site was found to be spatially and temporally variable. Volatilization decreased and atmospheric deposition increased from summer to fall. At the locations with higher levels of contamination, sum PAH release from sediments decreased by more than two orders of magnitude from summer to late fall. These data reflect the spatial heterogeneity and temporal variability of this site and demonstrate the importance of seasonality in assessing chemical movement at contaminated sites. Results from this study can inform future legacy site assessments to optimize remediation strategies and assess remediation effectiveness.

Remediation of heavily PAHs-contaminated soil with high mineral content from a coking plant using surfactant-enhanced soil washing

This study investigated the effectiveness of various surfactants at different concentrations in removing high concentrations of polycyclic aromatic hydrocarbons (PAHs) from soil with high mineral content, focusing on the impact of surfactant treatment on the mobility of the residual PAHs in soil. The results revealed that the cationic surfactant (CTMAB) inhibited removal of PAHs in the whole tested concentration range of 0.1–8 g/L. In contrast, the non-ionic and anionic surfactants (Triton X-100 and SDBS) significantly enhanced removal of PAHs as their amendment concentrations reached 2 g/L and above. Triton X-100 exhibited steadily increased efficacy with increasing amendment concentrations and maintained favorable solubilization capability when continuously amended, making it the preferable choice for remediating PAHs-contaminated soil. Surfactant and water washing processes altered soil physicochemical properties by removing some clay minerals (e.g., faujasite) and organic matter that can bind or sequester PAHs, potentially increasing their extractability and bioavailability in the washed soil, thereby posing higher ecological risks compared to the original one. Although soil washing decreased retention of the remaining PAHs in soil, it did not significantly impact PAHs release from soil by flowing water. These findings provide insights into the long-term effectiveness and ecological impacts of surfactant-enhanced washing as a potential remediation technique for PAHs-contaminated soil.

Tricyclic hydrocarbon fluorene attenuates ventricular ionic currents and pressure development in the navaga cod

The release of polycyclic aromatic hydrocarbons (PAHs) into the environment due to oil and diesel fuel spills is a serious threat to Arctic fish populations. PAHs produce multiple toxic effects in fish, but disturbance of electrical and contractile activity of the heart seems to be the most negative effect. Our study focused on the effects of fluorene, a tricyclic PAH resembling the well-investigated tricyclic phenanthrene, on major ionic currents and action potential (AP) waveform in isolated ventricular myocytes and on contractile activity in isolated whole hearts of polar navaga cod (Eleginus nawaga). Among the studied currents, the repolarizing rapid delayed rectifier K+ current IKr demonstrated the highest sensitivity to fluorene with IC50 of 0.54 μM. The depolarizing inward currents, INa and ICaL, were inhibited with 10 μM fluorene by 20.2 ± 2.8 % and 27.9 ± 8.4 %, respectively, thereby being much less sensitive to fluorene than IKr. Inward rectifier IK1 current was insensitive to fluorene (up to 10 μM). While 3 μM fluorene prolonged APs, 10 μM also slowed the AP upstroke. Resting membrane potential was not affected by any tested concentrations. In isolated heart experiments 10 μM fluorene caused modest depression of ventricular contractile activity. Thus, we have demonstrated that fluorene, a tricyclic PAH present in high quantities in crude oil, strongly impacts electrical activity with only slight effects on contractile activity in the heart of the polar fish, the navaga cod.

CO2 and H2O as sweep gases elevated carbon stability and decreased phytotoxicity of biochars

As a crucial pyrolysis factor for biochar production, the mechanistically effect of different sweep gases on the inherent multi-level chemical structure of biochars is poorly understood, impeding the widespread use of biochars as sustainable carbon-negative materials. This study investigated the effect of CO2 and H2O as sweep gases relative to N2 on the physic-chemical properties of biochars derived from sawdust (SBC-N/C/H) and pig manure (PBC-N/C/H) at 300–700 °C. Meanwhile, carbon sequestration potential and potential environmental risks of SBC-N/C/H and PBC-N/C/H were comprehensively evaluated. Unlike N2, CO2 showed a superior effect on biochar (especially SBCs with more carbonaceous substances), decreased the oxygenated-functional groups content in SBC-C (14.6%–28.1%) relative to SBC-N (25.5%–37.4%) via cracking reaction. Besides, CO2 stimulated the formation of pore structure in biochar (surface area increased from 15.2 m2/g in SBC700-N to 24.1 m2/g in SBC700-C) by boudouard reaction. H2O exhibited a similar but less pronounced effect with CO2, leading to a lower H/C ratio in biochar by aggravated demethylation of methoxyl groups and facilitating a more developed pore structure with water–gas reaction. Both CO2 and H2O enhanced the carbon stability of biochar and carbon sequestration potential in SBC500-C (30.1%) and SBC500-H (28.7%) was higher than SBC500-N (25.6%). Moreover, CO2 and H2O exhibited excellent performance in mitigating phytotoxicity of biochars (especially for PBCs) to radish and cucumber seeds via the reduced release of polycyclic aromatic hydrocarbons and heavy metals. These results proposed an effective approach to improve long-term carbon sequestration and environmental safety of biochars.

A study combining a sediment-seawater microcosm with multimedia fugacity model to evaluate the effect of tidal cycles on polycyclic aromatic hydrocarbon release from sediments

Estuarine sediments are key storage sites for persistent organic pollutants (POPs), and estuaries are strongly influenced by tides throughout the year. Although much work has been done concerning on POPs release, related questions on tidal action have not been considered in the release process. Herein, polycyclic aromatic hydrocarbons (PAHs) release from sediment to seawater was investigated under tidal action by combining a tidal microcosm with level IV fugacity model. The results showed that PAHs release with tidal action was 2.0–3.5 times the accumulation of that without tidal action. Tidal action was confirmed to influence strongly PAHs release from sediment to seawater. We also quantified suspended substance (SS) in the overlying water, and an obvious positive correlation between the PAHs concentration and SS content was found. In addition, an increase in seawater depth enhanced the intensity of tidal action, and more PAHs were released, especially dissolved PAHs. Moreover, the fugacity model results showed a good fit with the experimental results. The simulated values demonstrated that the PAHs release was accomplished via two processes, “rapid release” and “slow release”. And the sediment played a key role in the fate of PAHs and was a major sink in the sediment-seawater system.

COF-300/PVDF adsorbents with aligned microchannels for fast removal of polycyclic aromatic hydrocarbons (PAHs)

Anthropogenic release of polycyclic aromatic hydrocarbons (PAHs) in water bodies has raised global concerns due to their notorious toxicity and carcinogenicity, therating aquatic exosystems and human well-being. Adsorption processes have been proposed for PAHs remediation, but their practical applications are limited by the lack of high-performance adsorbents and effective manufacturing processes. Here, we present a facile and scalable method to produce a COF-300/PVDF composite as a high-performance adsorbent for PAHs removal. The composite comprises a porous PVDF substrate containing numerous aligned microchannels in its entire cross-section where COF-300 is fully coated. The adsorption capacities of the COF-300 powder towards two sample PAH pollutants, i.e. naphthalene and 1-naphthylamine, are 655 and 570 mg g−1, respectively, which are among the highest reported values. The composite adsorbent demonstrates better adsorption kinetics and removal efficiencies than the COF-300 powders at the same feed input of 1.44 L h-1g−1, and its superior performance has been further highlighted through a comparative study with a COF-300 pack column and COF-300/PVDF mixed matrix membranes. These results suggest that the newly developed COF-300/PVDF composite holds great potential in practical applications for PAHs removal.

Occurrence and risk assessment of PAHs from athletic fields under typical rainfall events.

Six polycyclic aromatic hydrocarbons (PAHs) including naphthalene (Nap), fluorene (Flu), phenanthrene (Phe), fluoranthene (Fla), pyrene (Pyr), and chrysene (Chr) were detected in runoff from five athletic fields during three rainfall events. The event mean concentration (EMC) of ∑6PAHs ranged from 3.96 to 23.23 μg/L, which was much higher than the EMC in urban traffic area runoff. Except for Nap, the PAH concentrations followed in the order of artificial turf > badminton court > basketball court > plastic runway > optennis court. The surface characteristics of the athletic fields, such as the composition of materials and roughness, played an essential role in the release of PAHs. ∑6PAHs concentration during the 2nd rainfall event (July 22nd) was the highest among the three rainfall events, indicating that high rainfall intensity facilitated the PAHs release. PAHs during three rainfall events showed little first flush effect except for the artificial turf during the 2nd (22nd July) and 3rd (29th July) rainfall events. The first flush effect could be affected by rainfall characters, PAH properties, and surface characteristics of athletic fields. Ecological risk assessment showed that PAHs in runoff corresponded to moderate-to-high risk, while health risk assessment showed that PAHs could pose a potential carcinogenic danger to human health via dermal contact.

Cyclic solubilization and release of polycyclic aromatic hydrocarbons (PAHs) using gemini photosensitive surfactant combined with micro-nano bubbles: a promising enhancement technology for groundwater remediation

Polycyclic aromatic hydrocarbons (PAHs) have posed serious risks to the groundwater environment. Surfactant-enhanced remediation (SER) is a promising strategy, as it can increase the solubilization efficiency of PAHs contaminants. However, this technology is still hampered due to low efficiency and high cost for the separation of pollutants after solubilization. Through the combination of micro-nano bubbles (MNBs) with a gemini photosensitive surfactant (N1, N2-bis[4-[4-[(4-butylphenyl) azo] phenoxy] butyl]-N1, N2-tetramethylethane-1,2-diammonium bromide, AzoPBT), herein we present a significantly enhanced efficiency of phenanthrene (Phe) solubilization and surfactant cycling. Notably, the presence of MNBs was conducive to the dissolution and release of Phe by reducing the CMC and γ of trans-AzoPBT (from 0.52 mmol/L and 28.94 mN·m−1 to 0.39 mmol/L and 27.88 mN·m−1) and increasing the difference of interfacial properties between trans and cis-AzoPBT, which was owing to the electrostatic interaction. Groundwater chemical parameters, i.e., ions, pH and organic matter would affect the solubilization ability of trans-AzoPBT. Mg2+ and Ca2+ inhibited the solubilization while SO42− promoted the solubilization, depending on their radius, electronic quantity and solution pH. A change in the HA level up to 8 mg/L had a negatively effect on the solubilization ability. High release rate (69.39 %) of cis-AzoPBT for Phe and high recovery rate (89.37 %) for tans-AzoPBT were obtained in the AzoPBT/MNBs mixed aqueous solution. Compared to MNBs combined with conventional cationic surfactants, AzoPBT/MNBs mixed aqueous solution exhibited better synergistic solubilization performance, and the apparent solubility of Phe increased from 26.74 % to 31.61 %. Overall, this study demonstrates the enhanced solubilization of PAHs by photosensitive surfactants combined with MNBs, which provides valuable insights of the effective utilization of surfactants in the remediation of PAHs-contaminated groundwater with SER technology.

Release of PAH from Secondary Products Made from End-of-Life Tire Recyclates into 20% Aqueous Ethanol as Assessment of Human Dermal Absorption

Compliance with the legal limits set at the European level for the content of polycyclic aromatic hydrocarbons (PAH), which are harmful to human health and the environment, is of central importance for the recycling of rubber, particularly end-of-life tires (ELT), into secondary products, e.g., elastic fall protection mats or anti-slip mats for the transport sector. However, different regulations associated with different analytical methods apply to newly produced tires on the one hand and secondary products made from ELT on the other. Given these discrepancies, ELT can potentially contain levels of PAH, which can be problematic when reused in consumer products. The total PAH content, however, is not without doubt a reliable risk indicator, which should ultimately be based primarily on the transfer of the substances from the product into the skin of human beings or their release into the environment. Accordingly, additional studies are required to determine the extent to which migration-based measurements are more suitable for risk assessment and how the PAH content correlates with migration. Complementing the recently published results of PAH content in different types of ELT, this study investigates the release of PAH for a range of typical secondary materials composed entirely or partly of ELT. In the present study, migration tests with 20% aqueous ethanol were applied, a methodology that has been shown in previous investigations by others to reflect human skin exposure well, and the resulting migration rates of PAH are determined.

Polycyclic aromatic hydrocarbons in Fildes Peninsula, maritime Antarctica: Effects of human disturbance

This study provides the first data on the distribution, sources, and transport dynamics of polycyclic aromatic hydrocarbons (PAHs) in Fildes Peninsula, Antarctica via summertime analyses of lakes, seawater, snow, and air in 2013. Relatively high PAH levels and similar composition profiles (dominance of two- and three-ring PAHs) in the investigated marine and terrestrial environmental matrices were found, indicating substantial primary emissions of petrogenic PAHs. This result was corroborated by nonequilibrium partitioning of atmospheric PAHs caused by release of anthropically-derived lighter PAHs and air mass movement trajectories mainly originated from the Antarctic marginal seas. Notable geographical disparities of PAH pollution in the various types of samples consistently suggested impacts of station-related activities, rather than long-range atmospheric transport, on PAHs in Fildes Peninsula. The lack for temperature dependence for gas-phase concentrations and various molecular diagnostic ratios of atmospheric PAHs demonstrated that the impact of local anthropogenic inputs on air PAH variability supersedes the re-emission effect. The derived air–water and air–snow exchanges of PAHs in this remote region indicated a disequilibrium state, partially associated with intense local emissions of PAHs. PAH outgassing from, and absorption into, lake and marine waters were both observed, probably due to differences in anthropogenic influences among sites, while the net deposition of gaseous PAHs into snow prevailed. The results of this study shed lights on the major importance of native anthropogenic sources in the footprint and fate of PAHs in the Fildes Peninsula, which merits further monitoring.

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.

The contribution of persistent organic pollutants to the environmental changes in Campania region, Italy: Results from the Campania Trasparente project

Over the last two decades, the Campania region in Italy has been the focus of public debate and concern about environmental issues. Using data from soil, water, air, vegetables, animal products, and human blood, a multimedia monitoring study was performed to measure the contribution of persistent organic pollutants (POPs) to pollution in the region. We report results for a range of POPs in the air, including organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and phthalate esters (PAEs). Most of these chemicals are ubiquitous, with higher concentrations occurring in the urban and metropolitan territory of Naples. The residues of OCPs are attributed to their historical use; however, evidence of recent usage of technical Endosulfan exists in some areas. Although petrogenic sources are widespread, the pyrogenic source has dominated the release of PAHs. The Naples metropolitan area (NMA) serves as a regional emitter of POPs, and the long-term soil re-emission of some POPs does still exist. There are certain risks related to soil-borne PAHs, mainly in the urban (e.g., the Bagnoli brownfield site) and NMA, and more subordinately, in other provincial areas.

Evaluating chemicals of emerging concern in the Ganga River at the two major cities Prayagraj and Varanasi through validated analytical approaches.

Evaluating environmental water quality means to assess and protect the environment against unfriendly impacts from various organic impurities emerging from industrial emissions and those released during harvesting. Potential risks related with release of polycyclic aromatic hydrocarbons (PAHs), pesticides and pharmaceuticals (PhAcs), and personal care products (PCPs) into the environment have turned into an increasingly serious issue in ecological safety. Monitoring helps in control of chemicals and ecological status compliance to safeguard specific water uses, for example, drinking water abstraction. A longitudinal review was carried out for 55 different persistent organic pollutants (POPs) for the Ganga River which passes through the urban areas of Prayagraj and Varanasi, India, through validated analytical approaches and measurement uncertainty (MU) estimation to assess their potential use for routine analysis. Furthermore, environmental risk assessment (ERA) carried out in the present study has revealed risk quotient (RQ) higher than 1 in a portion of the aquatic bodies. Using a conservative RQ strategy, POPs were assessed for having extensive risks under acute and chronic exposure, proposing that there is currently critical ecological risk identified with these compounds present in the Ganga River. In general, these outcomes demonstrate a significant contribution for focusing on measures and feasible techniques to minimize the unfavorable effects of contaminants on the aquatic environment.

Contributions of partition and adsorption to polycyclic aromatic hydrocarbons sorption by fractionated soil at different particle sizes.

Partition and adsorption of polycyclic aromatic hydrocarbons (PAHs) are critical mechanisms determining their fate at the solid-liquid interface. The complexity of soil composition makes it difficult to distinguish between partition and adsorption, and bates the accuracy of the research results. This study found that the composition and structure of the soil particles (SAs) of varying particle sizes were significantly different. Partition contributed significantly to phenanthrene (Phe) sorption in SAs over 0.002mm. However, PAHs had the highest sorption coefficient (Kd) in SA less than 0.002mm (SA-3), and the lower aqueous phase equilibrium concentration of Phe, the greater the adsorption effect. According to morphology and structural analysis, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), interactions of micropores, soil organic matter (SOM) and minerals enhanced the sorption of PAHs. Additionally, thermogravimetry and mass spectrometry (TG-MS) results proved that SOM could inhibit the release of PAHs adsorbed in SAs during heating process. We observed that the Log Koc of PAHs was the most important factor in determining the Kd in SAs applying principal component analyses (PCA), and they have significant linear relationships (R2=0.79-0.93). These findings provide new understandings on interface reactivity of PAHs sorption to soils and the development of interface model.

Leaching of Polycyclic Aromatic Hydrocarbons from the Coal Tar in Sewage Wastewater, Acidic and Alkaline Mine Drainage.

Polycyclic aromatic hydrocarbons (PAHs) have been a problem in the environment for an extended period. They are mostly derived from petroleum, coal tar and oil spills that travel and are immobilized in wastewater/water sources. Their presence in the environment causes a hazard to humans due to their toxicity and carcinogenic properties. In the study, coal tar was analyzed using Gas Chromatography–Mass Spectrometry (GC–MS) and a concentration of 787.97 mg/L of naphthalene, followed by 632.15 mg/L of phenanthrene were found to be in the highest concentrations in the various water sources such as sewage, alkaline and acid mine drainage. A design column was used to investigate the leaching process and assessments were conducted on 300 mL of the various water sources mentioned, with 5 g of coal tar added and with monitoring for 4 weeks. The influence of the physiochemical properties of the receiving water sources, such as sewage, and acid and alkaline mine drainage, on the release of PAHs from the coal tar was assessed. The acidic media was proven to have the highest release of PAHs, with a total concentration of 7.1 mg/L of released PAHs, followed by 1.2 mg/L for the sewage, and lastly, 0.32 mg/L for the alkaline mine drainage at room temperature.

Polycyclic aromatic hydrocarbons (PAHs) in Greater Cairo water supply systems.

Polycyclic aromatic hydrocarbons (PAHs) pose a constant threat to the environment and public health. There are numerous activities in the Greater Cairo area that emit and release significant amounts of PAHs. Concentrations of these PAHs are released into the air and mixed with surface water, limiting its use. In this study, 17 PAH compounds are mapped at eight sites along the Nile River and its tributaries in Greater Cairo. In addition, their removal efficiency is evaluated with the conventional treatment in eight water treatment plants. PAHs were analyzed using GC-MS from January to December 2018. Naphthalene, anthracene, fluorene, pyrene, and phenanthrene were detected. The total amount of PAHs in raw water was highest in Shamal Helwan (1,325 ± 631 ng/l) and lowest in Mostorod (468 ± 329 ng/l), and the removal ranged from 25 to 31%. Further research is needed to integrate other techniques to reduce PAHs using the conventional treatment, and more efforts should be made to reduce the presence and release of PAHs in raw water.