Release Of Polycyclic Aromatic Hydrocarbons Research Articles

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.

Polycyclic Aromatic Hydrocarbons: Evaluation of concentrations in environmental media in Bayelsa State

Background and aim Artisanal refining of crude oil is an illegal refining process that contributes to environmental pollution through the release of Polycyclic Aromatic Hydrocarbons (PAHs). PAHs compounds are known for their destructive effects on the environment as well as their harmful effects on human health. This study thus assessed the concentrations of PAHs in water, soil, and fish in communities where artisanal refining of crude oil is practiced in Bayelsa State. Materials and methods This descriptive, comparative study was conducted in Sampou (mildly exposed community), Gbarain, and Nembe (severely exposed communities) in Bayelsa State. Water, fish, and soil samples were collected using pre-existing environmental media collection guidelines and sent to the laboratory for GC-FID determination of the PAH concentrations. The data obtained were analyzed using the Statistical Package for Social Sciences (SPSS) software. Results Mean and (total) PAHs concentration in water samples obtained from Sampou was 3.50 ± 4.51 (59.59) μg/L; Gbarain 1.76 ± 4.35 (29.87) μg/L and Nembe 1.90 ± 4.20 (32.25) μg/L. A significant difference in the concentrations was also identified p-value: of 0.021. The mean concentration of PAHs in soil samples obtained from Sampou was 10.73 ± 15.53 (183.38) μg/kg; Gbarain 12.00 ± 19.57 (204.32) μg/kg and Nembe was 8.49 ± 10.07 (144.48) μg/kg. Finally, the mean concentration in fish samples obtained from Sampou was 5.62 ± 5.92 (95.43) μg/kg; Gbarain 3.81 ± 5.57 (64.75) μg/kg and Nembe 4.61 ± 5.33 (78.35) μg/kg. The difference in these concentrations was however not significant. Source diagnostic ratios of the PAHs in the water included Flt/(Flt + Pyr) ratio of 0.23, 0.16, and 0.21; Ant/(Ant + Phe) ratio of 0.87, 0.76, and 0.87 as well as BaA/(BaA + Chr) ratio of 0.43, 0.51 and 0.66 in Sampou, Gbarain and Nembe respectively. Conclusion Concentrations of total PAHs in water and fish samples obtained from the three communities exceeded the acceptable limits for ƩPAHs of 2.0 μg/L and 2 μg/kg in water and fish respectively stipulated by the United States Environmental Protection Agency and the Nigerian Petroleum Regulatory Authority. ƩPAHs concentrations from the samples obtained from Sampou were also higher than the other two communities. There is a need for regular environmental monitoring of PAH concentrations, especially in oil-producing communities, and a shift of focus toward the elimination of pyrolytic sources of PAH pollution.

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.

Using solid-phase microextraction during ultrasound reveals higher aqueous PAHs release from contaminated sediment

Ultrasound (US) releases polycyclic aromatic hydrocarbons (PAHs) from contaminated creosote sediments and degrades PAHs in aqueous solution. However, it is unclear how much PAHs release occurs during active US compared to after US is stopped. In this study, solid-phase microextraction (SPME) was used to determine aqueous PAH concentrations desorbed from Little Scioto River creosote contaminated sediment during exposure to 20 kHz ultrasound (US) at a power of 430 W L−1. First, SPME fiber-water partition coefficients,KSPME, were experimentally determined and shown to be comparable with previous studies. Next, PAH concentrations released into aqueous solution were determined by sequentially exposing fresh, conditioned SPME fibers in a reactor containing the contaminated sediment and DI for 10 min periods. Three consecutive 10 min periods each were measured during US and after US. Compared to mixing only, PAHs desorbed during ultrasound was significantly higher. In addition, for phenanthrene, anthracene, and fluoranthene, US showed significantly higher aqueous concentrations during US compared with after US. For these less soluble PAHs, desorption into the aqueous phase reaches and surpasses expected equilibrium aqueous concentrations. However, when US is ceased, PAHs appear to resorb onto sediment resulting in the lower concentrations measured in these PAH compounds after US that are similar to expected equilibrium aqueous concentrations. Typical analytical extraction methods for determining the effects of US require stopping treatment and may underestimate the potential US has for release of contaminants from sediment during US. Using SPME during US treatment reveals that the concentration of PAHs during US may surpass the expected equilibrium aqueous concentration of some PAHs congeners. To our knowledge, this higher concentration observed during US compared to after US has not been shown previously.

Sediment Remediation Using Activated Carbon: Effects of Sorbent Particle Size and Resuspension on Sequestration of Metals and Organic Contaminants.

Thin‐layer capping using activated carbon has been described as a cost‐effective in situ sediment remediation method for organic contaminants. We compared the capping efficiency of powdered activated carbon (PAC) against granular activated carbon (GAC) using contaminated sediment from Oskarshamn harbor, Sweden. The effects of resuspension on contaminant retention and cap integrity were also studied. Intact sediment cores were collected from the outer harbor and brought to the laboratory. Three thin‐layer caps, consisting of PAC or GAC mixed with clay or clay only, were added to the sediment surface. Resuspension was created using a motor‐driven paddle to simulate propeller wash from ship traffic. Passive samplers were placed in the sediment and in the water column to measure the sediment‐to‐water release of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and metals. Our results show that a thin‐layer cap with PAC reduced sediment‐to‐water fluxes of PCBs by 57% under static conditions and 91% under resuspension. Thin‐layer capping with GAC was less effective than PAC but reduced fluxes of high–molecular weight PAHs. Thin‐layer capping with activated carbon was less effective at retaining metals, except for Cd, the release of which was significantly reduced by PAC. Resuspension generally decreased water concentrations of dissolved cationic metals, perhaps because of sorption to suspended sediment particles. Sediment resuspension in treatments without capping increased fluxes of PCBs with log octanol–water partitioning coefficient (K OW) > 7 and PAHs with log K OW of 5–6, but resuspension reduced PCB and PAH fluxes through the PAC thin‐layer cap. Overall, PAC performed better than GAC, but adverse effects on the benthic community and transport of PAC to nontarget areas are drawbacks that favor the use of GAC. Environ Toxicol Chem 2022;41:1096–1110. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

North-south geographic heterogeneity and control strategies for polycyclic aromatic hydrocarbons (PAHs) in Chinese lake sediments illustrated by forward and backward source apportionments

As universal and supervirulent pollutants, understanding the potential sources of polycyclic aromatic hydrocarbons (PAHs) in lakes is critical for formulating pollutant control policies that will ensure the ecological safety of aquatic environments. Geographic heterogeneity of PAHs in lake sediments from China nationwide was investigated to indicate north-south dissimilarities in PAH levels and sources and propose specific PAH control strategies. Geographic PAH patterns showed that higher concentrations were found in the south compared to the north due to higher energy consumption and more intense industrial activities. Furthermore, the primary contributors in the south were high molecular weight (HMW) PAHs, whereas low molecular weight (LMW) PAHs were dominant in the north. The results of forward source apportionment based on the PAH emission method (EM) were consistent with the backward method using the positive matrix factorization (PMF) model, which verified the feasibility of the combined methods. Petroleum from transport was the dominant PAH source in the south, and purifying gasoline and diesel, promoting new energy vehicles and direct injection engines might effectively reduce PAH emission. Domestic coal was the main PAH source in the north, thereby adding active substance in coal and using cleaner energy could reduce PAH release.

Reusable Cavitand-Based Electrospun Membranes for the Removal of Polycyclic Aromatic Hydrocarbons from Water.

The removal of toxic and carcinogenic polycyclic aromatic hydrocarbons (PAHs) from water is one of the most intractable environmental problems nowadays, because of their resistance to remediation. This work introduces a highly efficient, regenerable membrane for the removal of PAHs from water, featuring excellent filter performance and pH-driven release, thanks to the integration of a cavitand receptor in electrospun polyacrylonitrile (PAN) fibers. The role of the cavitand receptor is to act as molecular gripper for the uptake/release of PAHs. To this purpose, the deep cavity cavitand BenzoQxCav is designed and synthetized and its molecular structure is elucidated via X-Ray diffraction. The removal efficiency of the new adsorbent material toward the 16 priority PAHs is demonstrated via GC-MS analyses at ng L-1 concentration. A removal efficiency in the 32%, to 99% range is obtained. The regeneration of the membrane is performed by exploiting the pH-driven conformational switching of the cavitand between the vase form, where the PAHs uptake takes place, to the kite one, where the PAHs release occurs. The absorbance and regeneration capability of the membrane are successfully tested in four uptake/release cycles and the morphological stability.

Distribution of polycyclic aromatic hydrocarbons in the sea water column

The most intensive traffic in the world is going in the Baltic Sea. Consequences of intensive navigation are illegal or accidental oil spills. Following a spill, the soluble fraction of polycyclic aromatic hydrocarbons (PAH) is rapidly released into the water column. These remain dissolved in seawater over an extended period of time, even should the insoluble fraction be removed. Therefore, it is necessary to know how fast and what polycyclic aromatic hydrocarbons start releasing from the film of spilled oil. During an experiment, it was aimed to determine maximal concentrations of that. PAH were analysed in the dissolved and suspended phases in the water column. The study was undertaken under controlled conditions so as to minimize the variability of environmental factors such as temperature and hydrodynamics. After two weeks of the experiment, the following low-molecular weight hydrocarbons were detected: naphthalene (Naph), phenanthrene (Phe) and anthracene (Antr). No high-molecular weight hydrocarbons were detected within the total time of the experiment (8 weeks). The distributions of PAHs were measured in the dissolved and suspended phases, where total concentration of PAHs ranged from 19.01 ng L-1 to 194.70 ng L-1 in the dissolved phase and from 5.14 to 63.92 ng L–1 in the suspended phase. The release of PAHs from the film started immediately after the spill reaching 194.70 ng L-1 in the dissolved phase and 63.92 ng L-1 in the suspended phase near the bottom of water column after 1 – 2 hours. In the dissolved phase, 2 – 3 ring PAHs dominated (60 – 80 %), whereas the highest amount of 4 – 6 ring PAHs (55 – 90 %) was found in the suspended phase.

Water-induced release of recalcitrant polycyclic aromatic hydrocarbons from soil organic matter during microwave-assisted solvent extraction

Polycyclic aromatic hydrocarbons (PAHs) in soil can be recalcitrant to solvent extraction after aging. We showed in this study that mixing a small amount of water in the extracting solvent during microwave-assisted extraction (MAE) can release recalcitrant PAHs, resulting in significant improvement in the analyzed concentrations. The improvement factor (F) for the total of 16 priority PAHs (∑PAH16) listed by the United States Environmental Protection Agency was 1.44–1.55 for field soils. By comparing the F values for different soil organic components, we demonstrated that the recalcitrant PAHs were primarily associated with biochar, humic acid (HA), and humin (HM), with the F values for ∑PAH16 of 1.94, 6.62, and 4.59, respectively. The results showed that the recalcitrant PAHs comprised a sequestered fraction and a desorption-limited fraction. NMR spectra showed that water worked alone at elevated temperature to promote hydrolysis of biochar and destroy the macromolecular structure, thus causing the release of the otherwise sequestered PAHs during MAE. The substantial reduction in F values for HA and HM after demineralization indicated sequestration of PAHs in organic-mineral complexes, which can be destroyed by hot water treatment. The release of the sequestered fraction was nonselective and independent of compound hydrophobicity. In comparison, the release of the desorption-limited fraction was positively affected by the hydrophobicity of PAHs and was facilitated by the presence of water in the extracting solvent. The results of this study provide important insights into the sequestration and release of recalcitrant PAHs in soil.

Phenanthrene alters the electrical activity of atrial and ventricular myocytes of a polar fish, the Navaga cod.

Oil and gas exploration in the Arctic can result in the release of polycyclic aromatic hydrocarbons (PAHs) into relatively pristine environments. Following the recent spill of approximately 17 500 tonnes of diesel fuel in Norilsk, Russia, May 2020, our study focussed on the effects of phenanthrene, a low molecular weight PAH found in diesel and crude oil, on the isolated atrial and ventricular myocytes from the heart of the polar teleost, the Navaga cod (Eleginus nawaga). Acute exposure to phenanthrene in navaga cardiomyocytes caused significant action potential (AP) prolongation, confirming the proarrhythmic effects of this pollutant. We show AP prolongation was due to potent inhibition of the main repolarising current, IKr, with an IC50 value of ~2 µM. We also show a potent inhibitory effect (~55%) of 1 µM phenanthrene on the transient IKr currents that protects the heart from early-after-depolarizations and arrhythmias. These data, along with more minor effects on inward sodium (INa) (~17% inhibition at 10 µM) and calcium (ICa) (~17% inhibition at 30 µM) currents, and no effects on inward rectifier (IK1 and IKAch) currents, demonstrate the cardiotoxic effects exerted by phenanthrene on the atrium and ventricle of navaga cod. Moreover, we report the first data that we are aware of on the impact of phenanthrene on atrial myocyte function in any fish species.

Effects of organic matter addition on chronically hydrocarbon-contaminated soil.

Soil is the recipient of organic pollutants as a consequence of anthropogenic activities. Hydrocarbons are contaminants that pose a risk to human and environmental health. Bioremediation of aging contaminated soils is a challenge due to the low biodegradability of contaminants as a result of their interaction with the soil matrix. The aim of this work was to evaluate the effect of both composting and the addition of mature compost on a soil chronically contaminated with hydrocarbons, focusing mainly on the recovery of soil functions and transformations of the soil matrix as well as microbial community shifts. The initial pollution level was 214ppm of polycyclic aromatic hydrocarbons (PAHs) and 2500ppm of aliphatic hydrocarbons (AHs). Composting and compost addition produced changes on soil matrix that promoted the release of PAHs (5.7 and 15 % respectively) but not the net PAH elimination. Interestingly, composting stimulated AHs elimination (about 24 %). The lack of PAHs elimination could be attributed to the insufficient PAHs content to stimulate the microbial degrading capacity, and the preferential consumption of easily absorbed C sources by the bacterial community. Despite the low PAH catabolic potential of the aging soil, metabolic shift was driven by the addition of organic matter, which could be monitored by the ratio of Proteobacteria to Actinobacteria combined with E4/E6 ratio. Regarding the quality of the soil, the nutrients provided by the exogenous organic matter contributed to the recovery of the global functions and species diversity of the soil along with the reduction of phytotoxicity.

The effects of adsorptive materials on microbial community composition and PAH degradation at the sediment cap–water interface

Capping with layers of inert or adsorptive materials is used to control the release of polycyclic aromatic hydrocarbons (PAH) in sediment but little is known about microbial degradation processes in these materials. A rich native microbial community inhabits the sediment bed, and capping media can influence enrichment and biodegradation activity of benthic microorganisms. The aim of this study was to evaluate the effects of capping media (sand, organoclay, and powdered activated carbon [PAC]) on microbial communities under oxic conditions typical of the cap–water interface, where naphthalene degradation (model PAH) is likely to be maximized. Bench scale experiments compared naphthalene concentrations, nahAc biomarker abundance, microbial community composition, and cellular attachment in systems amended with adsorptive and non-adsorptive capping materials. Results indicate that activated carbon promoted and enhanced bioactivity; PAC treatments showed high biodegradation rates, nahAc biomarker levels, and attached biological growth consistent with enrichment of the PAH-degrading genus Pseudomonae. In contrast, sand did not enhance biological activity compared to media-free systems. Naphthalene strongly influenced microbial community composition at the species level in all treatments except organoclay, which promoted biological signatures commonly associated with impeding degradation activity. Data overall suggest that adsorptive capping materials can both promote (PAC) and inhibit (organoclay) bioactivity in the surficial layer of caps, indicating that media selection is critical to the design of bioactive capping systems.

Acidification-Induced Distribution of Organo-Mineral Aggregates and Release of Polycyclic Aromatic Hydrocarbons in Red Soil from Central South China

Acid rain (AR) has become an important environmental problem in southern China. In addition, the pollution of polycyclic aromatic hydrocarbons (PAHs) in soils is increasingly drawing people's atten...

Diffusive mass flux of different polycyclic aromatic hydrocarbons (PAHs) and estimation of lifetime average daily dose in a soil micro-block system

The polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the environment, highly persistent to degradation, and remained in any system for an extended period. Their distribution in a soil system depends upon soil properties and the nature of PAH itself. Therefore, an experiment was conducted in the soil-block system to evaluate the release, transport, toxicity equivalents, and lifetime average daily dose (LADD) of different PAHs over 30 days by growing maize (Zea mays L.) plants. The soil was spiked at the rate of 500 ppb by different PAHs in soil-block systems from one side. After spiking, soil sampling was performed from four different distances {10, 20, 30, and 40 mm distance from the source (DFS)} in three intervals (5, 15, and 30 days) of time. Results depicted that the maximum diffusive mass flux (Jd) was obtained at 0–10 mm DFS after five days of sampling for all PAHs and a minimum from 30 to 40 mm DFS after 30 days of sampling. Out of all PAHs concentrations, three PAHs concentrations were in detectable range and high as compared to other PAHs. The fluoranthene was released maximum as compared to pyrene, and benzo[k]fluoranthene at all time interval samplings with and without plants. The concentration of all PAHs release was highest where plants were grown as compared to the samples obtained where no plants were grown. The growth of maize under PAHs application enhanced diffusion as compared to control (where no plants were grown). The LADD after 5 days of sampling was highest at 0–10 mm DFS as compared to 10–20 mm, 20–30 mm, and 30–40 mm DFS. Benzo[a]pyrene toxicity equivalency (BaPTEQ) data for fluoranthene, pyrene, and benzo (k)fluoranthene showed a range from 0.001 to 0.299 ng m3, 0.001–0.182 ng m3 and 0.001–0.202 ng m3, respectively. It was concluded that the presence of plants in a soil enhanced the diffusive mass flux of PAHs but also increased the LADD and BaPTEQ.

Contribution of Dissolved Organic Carbon in Mobilizing and Releasing High Molecular Weight Polycyclic Aromatic Hydrocarbons From Carbonaceous Material-Amended Soil

Introduction: Migration and mobilization of recalcitrant organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) in contaminated sites may endanger groundwater resources if considerable amounts of these compounds are mobilized and leached from solid phase into aqueous phase. The aim of the present study was to investigate the influence of biochar in two forms i.e. crushed and pulverized on immobilization and leaching behavior of high molecular weight (HMW) PAHs from contaminated soil into water as well as evaluation of contribution of dissolved organic carbon (DOC) in mobilization and release of HMW PAHs in crushed and pulverized biochar-amended soil, which was addressed for the first time in this study. Materials and Methods: Column leaching test was used to evaluate the leaching behavior of selected HMW PAHs from soil. Concentrations of PAHs in column leachates were determined using a GC/MS. Results: Findings showed strong sorption of the studied HMW PAHs to solid phase in both unamended and amended columns. Dibenz[a,h]anthracenewas not mobilized by water flow in any of the examined treatments and showed the greatest affinity to solid matrix. Mobility and leaching of most HMW PAHs were enhanced in the presence of crushed biochar. Direct correlation between detected concentrations of HMW PAHs in column percolates and DOC was found in biochar-amended soil. Conclusions: Biochar can be used as a promising cost-effective alternative to activated carbon in immobilization of PAHs in contaminated sites. However, contribution of DOC in mobilization of HMW PAHs from contaminated soils towards groundwater resources cannot be neglected.

Melting scenario affects the dynamics of polycyclic aromatic hydrocarbons released from snowpack

Melting snowpack can release semi-volatile organic contaminants (SVOCs) to both terrestrial and aquatic ecosystems, resulting in high ecological risk. The dynamics of polycyclic aromatic hydrocarbon (PAH) released from snowpack under controlled laboratory (intense melting) and field (melt/freeze melyting) snowmelt experiments was investigated in this study. In the laboratory: dissolved organic carbon (DOC) controlled the first flush of dissolved PAHs released from snowpack, except for napthelene, which is also affected by its solubility. The particles released early from snowpack usually contained high PAH concentrations (more than 100 μg g−1) and those released at the end contained low PAH concentrations (<20 μg g−1). The total PAH release pattern was determined by composition of all PAHs, including type 2 enrichment with a final peak and type 4 enrichment with double-peak. In field melting: all dissolved PAHs were released constantly, except naphthalene, which also showed a first flush but to a lesser extent. DOC controlled the release pattern of all detected dissolved PAHs from snowpack. High PAH concentrations were observed in particles released from snowpack at both the beginning and the end of the melting event. Concentrations of both total PAHs and PAH compositions in meltwater showed an increasing trend with melting time (from 1.3 to 4.0 μg l−1 and from 1.7 to 5.3 μg l−1 in meltwater from each of the two snowpacks), which coincided with Type 3 enrichment. Overall, our results suggest intense melting of snowpack results in the shift of some hydrophobic PAH compositions from Type 2 to Type 4 enrichment, depending on their partition coefficients. In contrast, melting with melt/freeze cycles may cause the shift of PAHs from Type 2 to Type 3 enrichment. Our study indicates changes of the melting scenarios due to global warming could affect dynamics of SVOCs released from snowpack, which is useful for risk management for water and soil quality.

Polycyclic aromatic hydrocarbons in fishes and some environmental samples on the coast of Ghana

Abstract. Osei-Yeboah E, Appiah-Opong R, Ofosuhene M. 2020. Polycyclic aromatic hydrocarbons in fishes and some environmental samples on the coast of Ghana. Ocean Life 4: 4-16. The shift in industrialization in our society, including mining of coal and minerals, drilling for oil has led to the accumulation of xenobiotic products and natural chemical substances. The activities from mining and drilling have continuously contributed to the release of polycyclic aromatic hydrocarbons (PAHs) and lead to their deposition in coastal environments. The process ultimately leads to bioaccumulation in plants and animals, creating dangerous pollutants. PAHs is a well-known cause of cancer, mutation, and embryonic pathologies. In Jubilee oil fields, Ghana, oil drilling is ongoing. However, onshore baseline environmental assessment of PAHs has not yet been performed. In this study, we performed an environmental assessment of some communities bordering the oil drilling fields to establish (i) levels of fish DNA adduct formation of fishes, (ii) levels of PHA in soil, plants, water, and fish. Several fishes from three study areas showed the presence of micronuclei as evidence in the examination of blood smears, although their mean micronucleated frequencies were below the threshold frequency of 15%. There was no statistical difference between their mean frequencies using one-way ANOVA analysis with a p-value &lt; 0.05 except that of the data from one species, Chloroscombrus chrysurus (Linnaeus, 1766). Reverse-phase HPLC analysis of fish, water, plant and soil samples collected from six study sites was performed. Two fish species Pomadasys incisus (Bowdich, 1825) at Aboadze and Thunnus alalunga (Bonnaterre, 1788) from Dixcove recorded four and one PAH compound, respectively with concentrations above the maximum contaminant levels of 30 ?g/kg set by the USEPA. The mean concentration of PAHs in water samples from two of the four study areas ranged from 1.4 to 1255 ?g/L. All samples recorded concentrations above the threshold limit value of 50 ng/L set by the World Health Organization. Sixty plant samples were collected across the six study areas, and only Erythrina senegalensis DC. and Ficus umbellata Vahl recorded the presence of PAHs with concentrations in the range of 0.15-4.70 mg/kg. Soil samples were collected from two different depths of 0-15 cm and 15-30 cm. The mean concentration of PAHs in surface soils (0-15cm) ranged from 0.1 to 95 mg/Kg, with that at 15-30 cm ranging from 0.12 to 105 mg/kg. The PAH composition profile in all the samples was similar, with 2- 3 ring PAHs being dominant, which is suggestive of a petrogenic source.