EPA Priority Pollutants Research Articles

Evaluating Lower Athabasca River Sediment Metal Concentrations from Alberta Oil Sands Monitoring Programs Using Predevelopment Baselines.

Since 1997, sediment metal concentrations have been monitored in the Alberta Oil Sands Region (AOSR) of the Lower Athabasca River by the Regional Aquatics Monitoring Program (RAMP; 1997-2002), the Joint Oil Sands Monitoring Program (JOSM; 2012-2014), and the Oil Sands Monitoring Program (OSM; 2015-present). However, it has remained difficult to differentiate industrial sources from natural sources and quantify the extent of pollution due to inadequate knowledge of predevelopment reference conditions. Here, baselines were constructed using predevelopment (i.e., pre-1967) sediment concentrations of US EPA priority pollutants (Be, Cr, Cu, Ni, Pb) and V, an element elevated in bitumen and associated waste materials, normalized to Al concentration in cores from floodplain and upland lakes within the AOSR to characterize the natural range of variability. The Lower Athabasca River sediment metal monitoring data were examined in the context of the predevelopment baselines. Most metals are below the threshold for minimal enrichment (<1.5x baseline) except for chromium (up to 4.8x) in some RAMP samples. The predevelopment baselines for sediment metal concentrations will be of particular importance as the oil sands industry potentially shifts from a no-release policy to the treatment and release of oil sands process waters directly to the Lower Athabasca River.

A prediction model of polycyclic aromatic hydrocarbon quarterly emissions based on GDP from a government policy perspective

Polycyclic aromatic hydrocarbons (PAHs) are a kind of carcinogenic, teratogenic and mutagenic pollutants that exist widely. In this study, a quarterly emission inventory of 16 PAHs listed as the US EPA priority pollutants was established by using the emission factor (EF) method. The results showed that the distribution of PAHs in different industries varied greatly with different year and quarter. The main characteristics of PAHs seasonal emission are that Q1 emission is the most and Q4 emission is the least. Among them, naphthalene and phenanthrene are the most important compounds. There are significant differences in PAHs emissions from different sources. Traffic and civil use emissions are the main sources. For example, in 2019, traffic emissions accounted for 20.9% and civil use emissions accounted for 78.3% of the total emissions. Then, a linear multiple regression model was established to predict the quarterly emission of PAHs. A vector autoregressive (VAR) approach was applied to analyse the correlation between the gross domestic product (GDP) and other macroeconomic parameters. This study could be used as a guide to provide recommendations for government policy and macro-control efforts.

Removal of naphthalene and phenanthrene in synthetic solutions by electro-oxidation coupled with membrane bioreactor.

Naphthalene (NAPH) and phenanthrene (PHEN) are two of the most abundant polycyclic aromatic hydrocarbons (PAHs) found in nature, and they are considered in the list of US EPA priority pollutants. The contribution of this research lies in the comprehensive analysis of a strategy for the coupling of electro-oxidation (EO) and biodegradation in a submerged membrane bioreactor (SMBR) with the objective to remove PAHs, using NAPH and PHEN as model compounds. The electrochemical degradation of NAPH and PHEN in aqueous synthetic solution has been carried out using two different anodes: Ti/IrO2 and Ti/SnO2. The effects of EO operating parameters (current density, reaction time, and pH) on the NAPH and PHEN removals were investigated applying 23 factorial design with both electrodes. Additionally, the EO effluents were analyzed for COD, NH4-N, and biodegradability (respirometry tests). The highest removals of both compounds were reached with Ti/IrO2 anode, at acidic conditions (pH of 2), current density of 50 mA cm-2, and electrolysis time of 60 min. However, the Ti/SnO2 anode allowed greater reduction of the biomass inhibition, which means that the enhancement of the EO effluent biodegradability was reached; therefore, this electrode was selected for the coupled EO-SMBR system, applying the operating conditions that improved the biodegradability of the effluent. The EO process allowed NAPH and PHEN removal efficiencies of 96 ± 5% and 94 ± 3%, respectively. The membrane bioreactor was operated with organic load of 0.6 ± 0.1 gCOD gVSS-1 d-1, hydraulic retention time of 6 h, and solid retention time of 30 d, obtaining average COD, NH4-N, NAPH, and PHEN removals of 98±0.5%, 91±6.4%, 99.1±0.96%, and 99.7±0.4% respectively. The sorption of phenanthrene onto the biomass had a low contribution, 0.9±0.2%, concluding that biodegradation was the main removal mechanism in the bioreactor. The coupled system EO-SMBR allowed high NAPH and PHEN removal efficiencies of 99.99±0.01 and 99.99±0.02%, respectively.

The multifunctional globin dehaloperoxidase strikes again: Simultaneous peroxidase and peroxygenase mechanisms in the oxidation of EPA pollutants

The multifunctional catalytic hemoglobin dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata was found to catalyze the H2O2-dependent oxidation of EPA Priority Pollutants (4-Me-o-cresol, 4-Cl-m-cresol and pentachlorophenol) and EPA Toxic Substances Control Act compounds (o-, m-, p-cresol and 4-Cl-o-cresol). Biochemical assays (HPLC/LC-MS) indicated formation of multiple oxidation products, including the corresponding catechol, 2-methylbenzoquinone (2-MeBq), and oligomers with varying degrees of oxidation and/or dehalogenation. Using 4-Br-o-cresol as a representative substrate, labeling studies with 18O confirmed that the O-atom incorporated into the catechol was derived exclusively from H2O2, whereas the O-atom incorporated into 2-MeBq was from H2O, consistent with this single substrate being oxidized by both peroxygenase and peroxidase mechanisms, respectively. Stopped-flow UV–visible spectroscopic studies strongly implicate a role for Compound I in the peroxygenase mechanism leading to catechol formation, and for Compounds I and ES in the peroxidase mechanism that yields the 2-MeBq product. The X-ray crystal structures of DHP bound with 4-F-o-cresol (1.42 Å; PDB 6ONG), 4-Cl-o-cresol (1.50 Å; PDB 6ONK), 4-Br-o-cresol (1.70 Å; PDB 6ONX), 4-NO2-o-cresol (1.80 Å; PDB 6ONZ), o-cresol (1.60 Å; PDB 6OO1), p-cresol (2.10 Å; PDB 6OO6), 4-Me-o-cresol (1.35 Å; PDB 6ONR) and pentachlorophenol (1.80 Å; PDB 6OO8) revealed substrate binding sites in the distal pocket in close proximity to the heme cofactor, consistent with both oxidation mechanisms. The findings establish cresols as a new class of substrate for DHP, demonstrate that multiple oxidation mechanisms may exist for a given substrate, and provide further evidence that different substituents can serve as functional switches between the different activities performed by dehaloperoxidase. More broadly, the results demonstrate the complexities of marine pollution where both microbial and non-microbial systems may play significant roles in the biotransformations of EPA-classified pollutants, and further reinforces that heterocyclic compounds of anthropogenic origin should be considered as environmental stressors of infaunal organisms.

Assessment of preservative migration from wood using a soil sachet method.

The ability of standard soils to capture heavy metals or polycyclic aromatic hydrocarbons (PAHs) from ammoniacal copper zinc arsenate (ACZA)- or creosote-treated wood, respectively, was assessed using pressure-treated posts immersed in a freshwater pond. The soil, in heat-sealed, permeable plastic mesh sachets, was able to intercept copper, zinc, arsenic, and PAHs migrating from the posts. Chemical levels were much higher immediately adjacent to the posts and declined with distance from the posts. Metals were consistently detected around ACZA-treated posts, while 10 of the 16 EPA priority pollutants were detected in at least one sachet embedded around creosote-treated posts at each sampling point. These results were consistent with traditional sediment sampling methods. The primary advantages of the sachets were their consistency in terms of soil characteristics and the ease with which they could be retrieved from the pond. Further studies are planned to better understand the role of soil characteristics in the sachets on the ability to capture migrating preservatives.

Polycyclic aromatic hydrocarbons in breast milk of obese vs normal women: Infant exposure and risk assessment

Biomonitoring of human breast milk is one of the best ways to identify body burdens of contaminants and associated risk estimation. The objectives of the current study were to evaluate milk concentrations of persistent organic pollutants (POPs), mainly polycyclic aromatic hydrocarbons (PAHs), associated exposure estimation, and the role of body mass index (BMI) in their bioaccumulation. A total of 45 breast milk samples were collected from 24 women with BMI > 30 (obese) and 21 women with BMI < 25 (18.5–24.9, normal) from 14 different counties surrounding Lubbock in west Texas/New Mexico (age range: 18–34 years). Samples were analyzed using high resolution gas chromatography coupled with mass spectrometry. A total of 31/45 (69%) of samples tested positive for PAHs. Phenanthrene was the most frequently detected PAH followed by pyrene and fluoranthene. The mean of individual PAH concentration for all samples ranged from 0 to 25.1 ng/g milk fat; the sum of all means of individual PAHs was 146.9 ng/g milk fat. The mean concentration of total PAHs in the BMI > 30 group was 224.8 ng/g milk fat, which was approximately 4 times the mean concentration of total PAHs in the BMI 18.5–24.9 group (57.9 ng/g milk fat). None of the samples from the BMI 18.5–24.9 group contained higher molecular weight (5–6 rings) PAHs, while in the BMI >30 group, a total of 11 PAHs including listed EPA priority pollutants were observed. In this study, benzo(b)fluoranthene was found to contribute the highest percentage of carcinogenic PAHs (32.08%), yet it was not detected in any samples from the BMI 18.5–24.9 group. The estimated total PAHs intakes by infants via obese and normal mothers' milk were 1.26 and 0.32 (μg/kg/day), which are 0.049 and 0.003 (μg/kg/day) B[a]P equivalent, respectively. These findings suggest that breastfed babies from obese mothers are potentially at higher risk of exposure to carcinogenic PAHs.

Upgrading biochar via co-pyrolyzation of agricultural biomass and polyethylene terephthalate wastes.

Spent polyethylene terephthalate (PETE) bottles were collected and co-pyrolyzed with rice straw (RS) to examine the characteristics and performance of biochar as a sorbent for various types of U.S. EPA priority pollutants, including 2,4-dinitrotoluene (DNT), 2,4-dichlorophenol (DCP), Pb, chromate (CrO42−), and selenate (SeO42−). During sorption of contaminants to PETE/RS-derived biochar, PETE residues from pyrolysis, pH, and pyrolysis temperature greatly affected the sorption process. Depending on the types of contaminants and experimental conditions, co-pyrolysis of PETE and RS may enhance the sorption of contaminants through different sorption mechanisms, including hydrophobicity, electrostatic force, ion exchange, surface complexation, and surface precipitation. Unlike other contaminants, selenate was reductively transformed by delocalized electrons from the graphitic structure in biochar. Our results strongly suggest that co-pyrolysis of PETE and agricultural wastes may be favorable to enhance the properties of biochar. In addition to syn-gas and bio-oil from co-pyrolysis, biochar may be a valuable by-product for commercial use.

Pyrolysis/GC/MS as a Method to Rapidly Profile Pyrotechnic Formulations for Objectionable Gaseous Emissions

A method to empirically determine the gaseous emissions produced from a pyrotechnic flare composition through the combination of gas chromatography and mass spectrometry is described. In this approach, milligram quantities of a model yellow signal flare composition and its individual polymeric constituents were subjected to pyrolysis at conditions that were guided via thermal analysis. Many volatile organic compounds and polycyclic aromatic hydrocarbons were identified as emission products even though thermochemical calculations fail to anticipate such products. Thus, these data may complement characterization of emission products predicted in silico. Pyrolysis of this pyrotechnic composition also demonstrated unique products formed via donation of nitrogen to aromatic fragments originating from resinous portions of the formulation. These products included EPA priority pollutants that were not formed by decomposition from staple ingredients. This work demonstrates that a variety of EPA priority pollutants...

Comparison of Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Different Environmental Media in the Urban Area of Daqing City

In order to investigate the various pollution characteristics and sources of polycyclic aromatic hydrocarbons (PAHs) in different environmental media, 23 street dust samples and four soil samples were collected in October 2012 in Daqing City. After extraction by Dionex ASE300 and purification, the content of the US EPA priority pollutants[16 individual PAH and total PAHs (ΣPAHs)] was determined by using gas chromatography-mass spectrometry (GC/MS). The results showed that the range of ΣPAHs content in street dust was 579.5-4656.7 ng·g-1, and the average content was 1839.7 ng·g-1. The mass percentage of PAHs in the street dust in different functional areas in Daqing showed a similar mass ratio range, with the average mass percentage of low ring (2-3 rings) PAHs of 37.9%, medium ring (4 rings) PAHs of 37.3%, and high ring (5-6 rings) PAHs of 24.8%. However, low ring PAHs, with mass ratios of 69.3%-99.97%, overwhelmingly dominated the Daqing soil, Daqing lake sediment, Daqing lakes, and Daqing ponds (data from literature). The distribution of ΣPAHs content was not significant among different functional areas and was closely related to the type of the plants around the sampling sites. The isomer ratio method confirmed that the sources of PAHs in the street dust in the study area were mixed sources, including oil spills, fuel oil combustion, and coal/biomass burning. Positive matrix factorization (PMF) results showed that the PAHs in the street dust in the center of Daqing originated from coal combustion, oil spill sources, industrial sources, and traffic sources, with contribution rates of 30.1%, 26.9%, 23.6%, and 19.3%, respectively, which were not exactly the same trend as that in other media.

Polycyclic aromatic hydrocarbons in house dust and surface soil in major urban regions of Nepal: Implication on source apportionment and toxicological effect

Urban centers have turned to be the provincial store for resource consumptions and source releases of different types of semi-volatile organic compounds (SVOCs) including polycyclic aromatic hydrocarbons (PAHs), bringing about boundless environmental pollutions, among different issues. Human prosperity inside urban communities is unambiguously dependent on the status of urban soils and house dusts. However, environmental occurrence and sources of release of these SVOCs are challenging in Nepalese cities, as exceptionally very limited data are accessible. This motivated us to explore the environmental fate, their source/sink susceptibilities and health risk associated with PAHs. In this study, we investigated the contamination level, environmental fate and sources/sink of 16 EPA's priority pollutants in surface soil and house dusts from four major cities of Nepal. Additionally, the toxicological effect of individual PAH was studied to assess the health risk of PAHs. Generally, the concentrations of ∑16PAHs in surface soil were 1.5 times higher than house dust, and ranged 767–6770ng/g dry weight (dw) (median 1810ng/g dw), and 747–4910 dw (median 1320ng/g dw), respectively. High molecular weight-PAHs both in soil and dust were more abundant than low molecular weight-PAHs, suggesting the dominance of pyrogenic source. Moderate to weak correlation of TOC and BC with PAHs in soil and dust suggested little or no role of soil organic carbon in sorption of PAHs. Source diagnostic ratio and principal component analysis indicated fossil fuel combustion, traffic/vehicular emissions and combustion of biomass are the principal sources of PAHs contamination in Nepalese urban environment. The high average TEQ value of PAHs in soil than dust suggested high risk of soil carcinogenicity compared to dust.

(Invited) Enabling Global Impact of Amperometric Gas Sensors

The enabling technology needed to catch the integrated “sensing-computing-communicating” economic engine of the early 21st century is that of environmental sensing. Human exposure to the environment [air, water, food, biologicals] is responsible for a major part of the disease burden of global populations and WHO predicts at least 6M premature deaths this year. A major route of exposure is inhalation and we all breathe the same air, and air pollution sensors that target the EPA priority pollutants of CO, NO2, Ozone, and SO2 are of increasing importance. One must measure something in order to understand and mitigate its effects and gas sensors do this job. Disruptive technologies, i.e. those that bridge the cost-performance gap, are required to field measurement capability globally. The amperometric gas sensor1,2 is an important contributor to environmental measurement capability. Recent advances have used printed electronics and semiconductor fabrication approaches to enable new commercialization opportunities. The ability to develop new sensor designs and to use advanced materials is key to setting up supply chain capability that has led to ever larger deployments of these sensors for breath/health measurements, environmental measurements, and safety. These new sensors exemplify a path to commercialization for high volume low-cost sensing with potential for high global societal impacts. 1] M. T. Carter, J. R. Stetter, M. W. Findlay and V. Patel, “Printed Amperometric Gas Sensors,” ECS Transactions, 50(12), 211-220 (2012). DOI 10.1149/0512.0211ecst. 2] Joseph R. Stetter and Jing Li, in Modern Topics in Chemical Sensing: Chapter 4, “Amperometric Gas Sensors – A Review,” Chemical Reviews, 108 (2), 2008, pp352-366.

Fungal Unspecific Peroxygenases Oxidize the Majority of Organic EPA Priority Pollutants.

Unspecific peroxygenases (UPOs) are secreted fungal enzymes with promiscuity for oxygen transfer and oxidation reactions. Functionally, they represent hybrids of P450 monooxygenases and heme peroxidases; phylogenetically they belong to the family of heme-thiolate peroxidases. Two UPOs from the basidiomycetous fungi Agrocybe aegerita (AaeUPO) and Marasmius rotula (MroUPO) converted 35 out of 40 compounds listed as EPA priority pollutants, including chlorinated benzenes and their derivatives, halogenated biphenyl ethers, nitroaromatic compounds, polycyclic aromatic hydrocarbons (PAHs) and phthalic acid derivatives. These oxygenations and oxidations resulted in diverse products and—if at all—were limited for three reasons: (i) steric hindrance caused by multiple substitutions or bulkiness of the compound as such (e.g., hexachlorobenzene or large PAHs), (ii) strong inactivation of aromatic rings (e.g., nitrobenzene), and (iii) low water solubility (e.g., complex arenes). The general outcome of our study is that UPOs can be considered as extracellular counterparts of intracellular monooxygenases, both with respect to catalyzed reactions and catalytic versatility. Therefore, they should be taken into consideration as a relevant biocatalytic detoxification and biodegradation tool used by fungi when confronted with toxins, xenobiotics and pollutants in their natural environments.

Occurrence and geographic distribution of polycyclic aromatic hydrocarbons in agricultural soils in eastern China.

Polycyclic aromatic hydrocarbons (PAHs) in agricultural soils, eastern China, were studied through a collection of surface samples at 109 sites. The study covered US EPA priority pollutants but also several non-priority isomers including some dibenzopyrenes which are expected to have higher toxic potentials. The total PAH concentrations varied extensively from 8.8 to 3880μg/kg, with a geometric mean of 158μg/kg. There were significant differences in both the concentrations and composition profiles between the south and the north regions. The overall geographical distribution pattern was strongly influenced by both the per capita gross domestic product and soil organic carbon (SOC) content. The former is an indicator of anthropogenic emissions while soil SOC content is associated with the accumulative capacities of the soils. The sequestration mechanism is an important process controlling fates of PAHs in agricultural soil.

Background concentrations of PAHs and metals in surface and subsurface soils collected throughout Manhattan, New York

ABSTRACTThis article summarizes the results from a survey of polycyclic aromatic hydrocarbon (PAH) and metal concentrations measured in surface and subsurface soil samples that were collected from background locations throughout Manhattan, New York, between August 2005 and May 2006. The 95th percentile total 16 US EPA Priority Pollutant PAH concentrations in surface and subsurface soils were 24.8 and 53.1 mg/kg, respectively. Diagnostic PAH source ratios for surface and subsurface soils are presented, which provide plausible bounds for where these ratios would and would not be able to confidently differentiate background soils from soil samples that are impacted by PAH contamination. The 95th percentile concentrations for lead in surface and subsurface soils were 891 and 2,540 mg/kg, respectively, and the 95th percentile concentrations for mercury in surface and subsurface soils were 1.9 and 2.7 mg/kg, respectively. A not-unexpected finding of the study was that most surface soils and all subsurface soils contained a relatively high fraction of anthropogenic carbon, in addition to the presence of historic fill materials such as glass, brick, coal, and slag from more than 400 years of human activity on Manhattan Island. The concentration ranges for PAHs and metals measured in these background soil samples, coupled with the visual observations of historic fill materials in nearly all soil samples, emphasize that soils in Manhattan are altogether different from rural soils and thus warrant a different framework for site management decisions than rural soils.

Beyond 16 Priority Pollutant PAHs: A Review of PACs used in Environmental Forensic Chemistry

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in soils and sediments, particularly in urbanized environments in which the concentrations of 16 (or so) PAHs are regulated. Distinguishing among the numerous PAH sources is of practical and legal concern and thereby is often an objective of environmental forensic chemistry studies. Studies of prospective sources and impacted soils and sediments that rely upon the 16 U.S. EPA Priority Pollutant PAHs are disadvantaged, as these few compounds generally lack the specificity to distinguish among different PAH sources in the environment. Advances in analytical and interpretive methods over several decades have shown that different PAH sources can be more defensibly distinguished using modified EPA Method 8270 that, among other improvements, measure many other polycyclic aromatic compounds (PACs) that co-occur with the Priority Pollutant PAHs in different sources and in the environment. The PACs include variously-alkylated PAHs and polycyclic aromatic sulfur heterocyclics (PASHs) homologs and individual isomers, which are herein reviewed. Collectively, these PACs provide a higher degree of specificity among PAC sources and can be used to understand the effects of weathering on PAH assemblages. Despite their diagnostic capacity, PACs should not be relied upon at the exclusion of other compound groups (e.g., petroleum biomarkers) in most environmental forensic chemistry studies. In light of these advances, source characterization studies that rely only upon the 16 (or so) Priority Pollutant PAHs warrant considerable caution.

PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas.

Recent studies have concluded that coal-tar-based pavement sealants are a major source of polycyclic aromatic hydrocarbons (PAHs) in urban settings in large parts of the United States. In 2006, Austin, TX, became the first jurisdiction in the U.S. to ban the use of coal-tar sealants. We evaluated the effect of Austin's ban by analyzing PAHs in sediment cores and bottom-sediment samples collected in 1998, 2000, 2001, 2012, and 2014 from Lady Bird Lake, the principal receiving water body for Austin urban runoff. The sum concentration of the 16 EPA Priority Pollutant PAHs (∑PAH16) in dated core intervals and surficial bottom-sediment samples collected from sites in the lower lake declined about 44% from 1998-2005 to 2006-2014 (means of 7980 and 4500 μg kg(-1), respectively), and by 2012-2014, the decline was about 58% (mean of 3320 μg kg(-1)). Concentrations of ∑PAH16 in bottom sediment from two of three mid-lake sites decreased by about 71 and 35% from 2001 to 2014. Concentrations at a third site increased by about 14% from 2001 to 2014. The decreases since 2006 reverse a 40-year (1959-1998) upward trend. Despite declines in PAH concentrations, PAH profiles and source-receptor modeling results indicate that coal-tar sealants remain the largest PAH source to the lake, implying that PAH concentrations likely will continue to decline as stocks of previously applied sealant gradually become depleted.

Birnessite-induced mechanochemical degradation of 2,4-dichlorophenol

DCP (2,4-dichlorophenol) is the key-intermediate in the synthesis of some widely used pesticides and is an EPA priority pollutant. The mechanochemical breakdown of DCP loaded on birnessite (δ-MnO2), montmorillonite saturated with Na+ or Cu2+ and hematite was investigated. Mechanical force was applied by grinding of mixtures of DCP and the minerals, using mortar and pestle. Grinding of DCP for 5min with the montmorillonites or with hematite resulted in negligible degradation during grinding, while grinding with birnessite induced the immediate degradation of 90% of the loaded DCP. Incubation for 24h after grinding did result in up to 30% degradation of the DCP loaded on the other minerals tested.HPLC and LC–MS analysis revealed that the transformation of DCP yielded oligomerization products as well as partial dechlorination. DCP degradation on birnessite was accompanied with a substantial increase in the extractability of manganese from the mineral into an acidic aqueous solution, indicating that Mn(IV) in the mineral transformed into Mn(II) and that birnessite served as an electron acceptor in the transformation. The oligomerization and partial dechlorination brought about by grinding, suggest a reduction in bioavailability and toxicity.

DISTRIBUTION OF POLYCYCLIC AROMATIC HYDROCARBONS IN SURFACE SEDIMENTS OF KOH SICHANG ANCHORAGE AREA, THAILAND

The levels and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in surface sediments of Koh Sichang anchorage area, Thailand using gas chromatography with flame-ionization detection (GC/FID). The total concentrations of 16 PAHs US EPA priority pollutants varied from 65.2 to 18,970 ng/g dw, with a median concentration of 282±3,660 ng/g dw. The sediment samples were classified as moderately contaminated compared to those observed in other regions. PAH compositional signatures of surface sediments of the study area were dominated by higher molecular weight PAHs (4-6 rings) comprising about 87 per cent of total PAHs concentrations. Dibenzo[a,h]anthracene, benzo[b]fluoranthene, benzo[g,h,i]perylene, benzo[a]pyrene, fluoranthene, indeno[1,2,3-cd]pyrene, and pyrene represented the highest fractions in most surface sediment samples. Source apportionment using diagnostic PAH ratios indicated that composition of PAHs in most sediment samples originated mainly from incomplete combustion of organic matter (pyrolytic origin), with a mixture of pyrolytic and petrogenic PAHs were observed in some of the study sites. The presence of almost all human carcinogenic PAHs in the study area indicated that these sediments can be considered contaminated sites, suggesting that future monitoring programs together with an effective coastal management program must be implemented to ensure health and safety for all.

Spatial variations in polycyclic aromatic hydrocarbons concentrations at surface sediments from the Cyprus (Eastern Mediterranean): Relation to ecological risk assessment

The objective of the present study was to evaluate the distribution, sources, origins, and environmental risk assessment of polycyclic aromatic hydrocarbons (16 US EPA priority pollutants) pollution in 23 surface sediments from Cyprus coast. The mean total polycyclic aromatic hydrocarbons (PAHs) concentrations in the sediments from Gemi Konagi, Girne and Gazi Magusa areas were found 47, 52 and 50ng/g, respectively. Molecular ratios and principle component analysis indicated that PAH pollution originated mainly from fossil sources, with higher pyrolytic contributions. The 2–3 ring PAHs were dominant in Cyprus sediments. Concentrations of PAHs observed in this study were compared with available soil quality guidelines and the concentrations were lower than the guideline values. The guideline values suggested that the Cyprus sediments were likely to be not contaminated by toxic PAH compounds.

Chemical and bioanalytical characterisation of PAHs in risk assessment of remediated PAH-contaminated soils

Polycyclic aromatic hydrocarbons (PAHs) are common contaminants in soil at former industrial areas; and in Sweden, some of the most contaminated sites are being remediated. Generic guideline values for soil use after so-called successful remediation actions of PAH-contaminated soil are based on the 16 EPA priority pollutants, which only constitute a small part of the complex cocktail of toxicants in many contaminated soils. The aim of the study was to elucidate if the actual toxicological risks of soil samples from successful remediation projects could be reflected by chemical determination of these PAHs. We compared chemical analysis (GC-MS) and bioassay analysis (H4IIE-luc) of a number of remediated PAH-contaminated soils. The H4IIE-luc bioassay is an aryl hydrocarbon (Ah) receptor-based assay that detects compounds that activate the Ah receptor, one important mechanism for PAH toxicity. Comparison of the results showed that the bioassay-determined toxicity in the remediated soil samples could only be explained to a minor extent by the concentrations of the 16 priority PAHs. The current risk assessment method for PAH-contaminated soil in use in Sweden along with other countries, based on chemical analysis of selected PAHs, is missing toxicologically relevant PAHs and other similar substances. It is therefore reasonable to include bioassays in risk assessment and in the classification of remediated PAH-contaminated soils. This could minimise environmental and human health risks and enable greater safety in subsequent reuse of remediated soils.