Characterization of Naturally-occurring and Anthropogenic PAHs in Urban Sediments-Wycoff/Eagle Harbor Superfund Site

Polycyclic aromatic hydrocarbons (PAH) are ubiquitous constituents in urban sedimentary environments. The accurate characterization of their source(s) in sediments influences decisions regarding the liability for clean-up and remedial options. In this study, an extensive PAH dataset that included 50 non-alkylated (parent) and alkylated PAH groups and isomers was acquired using a modified EPA Method 8270 for the study of 5 cm intervals from 10 sediment cores (28-78 cm) obtained from the Eagle Harbor Superfund Site on Bainbridge Island, Washington. Conventional hydrocarbon "fingerprinting" and the PAH profiles in the Pb 210 age-dated cores revealed three primary PAH sources to the sediments over the past 220 years, namely (1) naturally occurring background; (2) urban runoff, and (3) creosote, the latter resulting from prior operations at the former Wyckoff wood-processing facility located on the Harbor. Naturally occurring background PAH in the pre-industrial (<1900) sediments were dominated by perylene, 1,7-dimethylphenan-threne (derived from the oxidation of abietic acid resins), and pyrogenic PAH most likely derived from historic forest fires. The concentration of PAH total in these pre-industrial sediments was consistently less than 1 mg/kg (dry). Urban runoff in the post-industrial (>1930) sediments was dominated by low but consistent concentrations (10-20 mg/kg dry) of pyrogenic PAM derived primarily from the combustion of fossil fuel(s). The creosote-impacted sediments in the post-industrialized sediments contained high concentrations (1000-140,000 mg/kg dry) of pyrogenic PAH associated with distilled, coal-derived liquids.     

Removal of polycyclic aromatic hydrocarbons from soil: a comparison between bioremoval and supercritical fluids extraction

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic substances which are resistant to environmental degradation due to their highly hydrophobic nature. Soils contaminated with PAHs pose potential risks to human and ecological health, therefore concern over their adverse effects have resulted in extensive studies on their removal from contaminated soils. The main purpose of this study was to compare experimental results of PAHs removal, from a natural certified soil polluted with PAHs, by biological methods (using bioaugmentation and biostimulation in a solid-state culture) with those from supercritical fluid extraction (SFE), using supercritical ethane as solvent. The comparison of results between the two methods showed that maximal removal of naphthalene, acenaphthene, fluorene, and chrysene was performed using bioremediation; however, for the rest of the PAHs considered (fluoranthene, pyrene, and benz(a)anthracene) SFE resulted more efficient. Although bioremediation achieved higher removal ratios for certain hydrocarbons and takes advantage of the increased rate of natural biological processes, it takes longer time (i.e. 36 d vs. half an hour) than SFE and it is best for 2-3 PAHs rings.     

Determination of polycyclic aromatic hydrocarbons in urban street dust: implications for human health

The determination of sixteen polycyclic aromatic hydrocarbons in urban street dust has been done. Samples were collected from 12 sampling locations in a city centre location (Newcastle upon Tyne, north east England) and extracted using in situ pressurised fluid extraction followed by gas chromatography mass spectrometry. From the results it was possible to identify three groups, with respect to PAH concentration, with PAH contents ranging between 0.6-2.3 mg kg⁻¹, 15.6-22.5 mg kg⁻¹ and 36.1-46.0 mg kg⁻¹. The total PAH content of samples from these sampling sites has been compared to 22 urban locations around the world; comparable levels were found in these samples compared to the other cities around the world.The potential source of PAHs has been investigated by investigating the proportion of pyrogenic and petrogenic material in urban street dust using specific individual PAH ratios. The results indicate that the PAH content of urban street dust from the chosen sites are more likely to be due to pyrogenic sources i.e. vehicle exhaust emissions. The particle size fractions (<63 μm; 63-125 μm; 125-250 μm; 250-500 μm; 500-1000 μm; and 1000-2000 μm) of individual PAHs in three selected sampling sites was investigated. In two of the selected sites the PAH content was independent of particle size whereas in sampling site 10 elevated PAH levels are noted in the <63 μm size fraction. Sampling site 10 is located at the junction of three road tributaries which are used as major access points to the east of the city centre. Finally, the potential health risk for unintentional consumption of PAHs was assessed in terms of a mean daily intake (based on an ingestion rate of 100 mg d⁻¹). It was found that all 4-6 membered ring PAHs had concentrations in excess of the mean daily intake thereby reflecting a potential health risk, particularly in the smallest size particle fractions.     

Estimating risk at a Superfund site using passive sampling devices as biological surrogates in human health risk models

Passive sampling devices (PSDs) sequester the freely dissolved fraction of lipophilic contaminants, mimicking passive chemical uptake and accumulation by biomembranes and lipid tissues. Public Health Assessments that inform the public about health risks from exposure to contaminants through consumption of resident fish are generally based on tissue data, which can be difficult to obtain and requires destructive sampling. The purpose of this study is to apply PSD data in a Public Health Assessment to demonstrate that PSDs can be used as a biological surrogate to evaluate potential human health risks and elucidate spatio-temporal variations in risk. PSDs were used to measure polycyclic aromatic hydrocarbons (PAHs) in the Willamette River; upriver, downriver and within the Portland Harbor Superfund megasite for 3 years during wet and dry seasons. Based on an existing Public Health Assessment for this area, concentrations of PAHs in PSDs were substituted for fish tissue concentrations. PSD measured PAH concentrations captured the magnitude, range and variability of PAH concentrations reported for fish/shellfish from Portland Harbor. Using PSD results in place of fish data revealed an unacceptable risk level for cancer in all seasons but no unacceptable risk for non-cancer endpoints. Estimated cancer risk varied by several orders of magnitude based on season and location. Sites near coal tar contamination demonstrated the highest risk, particularly during the dry season and remediation activities. Incorporating PSD data into Public Health Assessments provides specific spatial and temporal contaminant exposure information that can assist public health professionals in evaluating human health risks.     

Contrasting effects of black carbon amendments on PAH bioaccumulation by Chironomus plumosus larvae in two distinct sediments: role of water absorption and particle ingestion

Two sediment matrices with different characteristics were amended with chars from different sources for bioaccumulation assay with filter-feeding Chironomus plumosus larvae. Chars greatly decreased porewater concentrations of PAHs (C_iw) measured using polyethylene devices in sediments. In organic rich sediment matrix-based systems where suspended char particles were absent, PAH concentrations in larvae (C_iB) were significantly correlated with C_iw, and there was no difference in water-based bioaccumulation factors (BAFs) between different treatments, suggesting that water absorption was the main contaminant uptake route for larvae. In organic poor sediment matrix-based systems where suspended char particles were present, poor Pearson correlation between C_iB and C_iw was found, but there was a significant linear increase of BAF values with char contents, which indicated that ingestion of suspended char particles could also be important for PAH bioaccumulation. Therefore, we need to rethink of the effectiveness and risks for the application of black carbon to sediment/soil remediation.     

Variations in concentrations and compositions of polycyclic aromatic hydrocarbons (PAHs) in coals related to the coal rank and origin

The release of unburnt coal particles and associated polycyclic aromatic hydrocarbons (PAHs) may cause adverse impacts on the environment. This study assessed variations in the concentration and composition of PAHs in a set of fifty coal samples from eleven coal basins worldwide. The maximum PAH concentrations at high volatile bituminous rank were recorded in samples from a single basin. Considering the entire sample set, the highest PAH concentrations were in fact found outside of this rank range, suggesting that the maceral composition and thus the coal’s origin also influenced PAH concentrations. The examination of the PAH compositions revealed that alkylated 2-3 ring PAHs remain dominant compounds irrespective of coal rank or origin. Multivariate analysis based on PAH and maceral content, bulk and maturity parameters allowed the recognition of seven groups with different rank and origin within the coal sample set.     

Distribution and sources of polycyclic aromatic hydrocarbons in Wuhan section of the Yangtze River, China

Polycyclic aromatic hydrocarbons (PAHs) are important organic contaminants with great significance for China, where coal burning is the main source of energy. In this study, concentrations, distribution between different phases, possible sources and eco-toxicological effect of PAHs of the Yangtze River were assessed. PAHs in water, suspended particulate matters (SPM) and sediment samples at seven main river sites, 23 tributary and lake sites of the Yangtze River at the Wuhan section were analyzed. The total concentrations of PAHs in the studied area ranged from 0.242 to 6.235 μg/l in waters and from 31 to 4,812 μg/kg in sediment. The average concentration of PAHs in SPM was 4,677 μg/kg, higher than that in sediment. Benzo(a)pyrene was detected only at two stations, but the concentrations were above drinking water standard. The PAHs level of the Yangtze River was similar to that of some other rivers in China but higher than some rivers in foreign countries. There existed a positive relationship between PAHs concentrations and the TOC contents in sediment. The ratio of specific PAHs indicated that PAHs mainly came from combustion process, such as coal and wood burning. PAHs may cause potential toxic effect but will not cause acute biological effects in sedimentary environment of the Wuhan section of the Yangtze River.     

受氯代烃类污染的地下水环境修复研究进展

越来越多的地下水源正遭受氯代烃类有机物的污染,氯代烃类的地下环境行为及其污染环境的修复技术是当前环境学界的一个热点。目前修复这类污染环境的技术主要有抽出处理、渗透性反应墙和生物修复等。其中研究最多、应用最广的是利用表面活性剂强化抽出处理技术、零价铁降解氯代烃类的渗透性反应墙技术以及原位强化生物修复技术。零价铁反应墙如何长期稳定运行是目前的研究难题,也是该技术的发展目标。强化生物修复是具有巨大发展潜力的一项新兴技术,构建一个能同时降解多组分污染物的微生物生态群落并成功引入污染场地发挥最大功效,是地下水环境生物修复技术研究中的难点,也将是热点。     

How does the brown mussel Perna perna respond to environmental pollution? A review on pollution biomarkers

The brown mussel Perna perna (Linnaeus, 1758) is a valuable resource for aquaculture in tropical and subtropical coastal regions. It presents desirable characteristics for biomonitoring, including being sessile, widely distributed and abundant, and is a filter-feeder able to accumulate several classes of pollutants (e.g., metals, hydrocarbons, among others). Mussels’ biological responses to pollution exposure can be measured as biomarkers, which include alterations ranging from molecular to physiological levels, to estimate the degree of environmental contamination and its effects on biota. This full review compiles two decades (2000–2020) of literature concerning biological effects on P. perna mussel caused by environmental pollutants (i.e., metals, hydrocarbons, and emerging pollutants), considering environmental and farm-based biomonitoring. Biochemical markers related to mussels’ oxidative status were efficient for the biomonitoring of metals (i.e., antioxidant enzymes associated with oxidative damage in biomolecules). Genotoxicity and cytotoxicity indicators (i.e., comet, micronucleus, and neutral red assays) provided a depiction of hydrocarbon contamination. The neutral red assay gave a time-concentration cytotoxic response to a wide range of pollutants, including emerging pollutants (e.g., pharmaceuticals and biocides) and hydrocarbons. Perna perna hemocyte parameters provided a useful approach for biocide biomonitoring. This paper summarizes useful biomarkers from molecular to physiological levels in this mussel species used to identify and quantify the degree of coastal pollution. An integrated biomarker analysis may provide a way to overcome possible biomarker variations and assess multi-polluted sites. Nevertheless, it is necessary to investigate biomarker variations according to natural factors (e.g., season and gonad maturation stage) to standardize them for trustworthy biomonitoring.     

Investigation of the sources of aliphatic hydrocarbons in the mussel Mytilus edulis from north sea oil production platforms by Capillary glc and CGCMS†

Aliphatic hydrocarbons isolated from mussels collected over a 20 month period from three North Sea Forties field oil production platforms have been examined by capillary gas chromatography and gas chromatography‐mass spectrometry.

The biological hydrocarbons consist predominantly (300–700 μh g^‐1 lipid) of C₃₁ and C₃₃ n‐alkenes with 2, 3 and 4 double bonds probably derived from a dietary intake of Emiliania huxleyi, a microscopic coccolithophorid alga. In some of the mussels C₁₈, C₂₀ and C₂₂ n‐alkanes are present in unusually high abundance compared to their odd carbon number homologues. Possible reasons for this distribution are discussed.

The concentrations of fossil fuel hydrocarbons (mainly unresolved complex mixtures) in the mussels ranged from 330 to 5,298 μg g^‐1 of lipid. No significant increase in values was detected two months after the start of discharge of treated Forties production water from the Forties D platform.

To determine the pollutant hydrocarbon sources, the sterane and terpane distributions of hydrocarbon fractions isolated from the mussels and from a number of fossil fuels, including Forties crude oil, were examined by mass fragmentography. The steranes in the mussels from the Forties C and D platforms contained higher proportions of regular 14α(H), 17α(H) components than Forties oil in which the steranes were mainly 13ß(H), 17α(H) diasteranes. In addition, the terpane distributions of the mussel fractions differed markedly from that of Forties crude oil, particularly in the relative abundance of diterpanes to triterpanes, which was higher in the mussel fractions than in the oil, and in the absence of 17α(H), 18α(H), 21ß(H)‐18, 30‐bisnorhopane, a known component of Forties crude. Furthermore, the ratio of C₂₉ to C₃₀ triterpanes was greater than unity in the mussels but much less than unity in the Forties oil. These data preclude Forties or other similar North Sea crudes as the major source of pollutant aliphatic hydrocarbons in the mussels. The relative concentrations and distributions of steranes and triterpanes suggest that the most likely source of pollutants is a Middle Eastern based oil derived either from rig activities, or from background pollution in the North Sea. The low concentration of ≥ C₂₇ steranes in the more polluted mussels (e.g. Forties B; UCM > 200 ppm dry wt.) suggests that gas oils used on the platforms may be the major source of petrogenic hydrocarbons in these samples.