PAHs In Sediments Research Articles

Effect-directed analysis and mixture effects of AhR-active PAHs in crude oil and coastal sediments contaminated by the Hebei Spirit oil spill

The major AhR-active PAHs were identified in crude oil and oil-contaminated sediments by use of effect-directed analysis. As part of the study, an enhanced potency balance analysis was conducted by establishing the novel relative potency values of (alkyl)-PAHs from the H4IIE-luc bioassay. Silica gel column fractionation of crude oil resulted in greater AhR-mediated potencies in fractions of aromatics (F2) and resins (F3), and such trend was also observed for field collected sediment samples. AhR-mediated potencies of six F2 sub-fractions from HPLC indicated that the majority of F2 responses were attributable to 3–4 ring aromatics. Target PAHs including C4-phenanthrene, C1-chrysene, and C3-chrysene in sediments explained ∼18% of the bioassay-derived TCDD-EQs, however, the unknown AhR agonists and potential mixture effects remain in question. Overall, the AhR-potency and antagonistic potential of residual oil in sediment tended to decrease over time, thus monitoring of weathering process would be key for the post management of oil-contaminated sites.

Effects of oil dispersant on solubilization, sorption and desorption of polycyclic aromatic hydrocarbons in sediment–seawater systems

This work investigated effects of a prototype oil dispersant on solubilization, sorption and desorption of three model PAHs in sediment–seawater systems. Increasing dispersant dosage linearly enhanced solubility for all PAHs. Conversely, the dispersant enhanced the sediment uptake of the PAHs, and induced significant desorption hysteresis. Such contrasting effects (adsolubilization vs. solubilization) of dispersant were found dependent of the dispersant concentration and PAH hydrophobicity. The dual-mode models adequately simulated the sorption kinetics and isotherms, and quantified dispersant-enhanced PAH uptake. Sorption of naphthalene and 1-methylnaphthalene by sediment positively correlated with uptake of the dispersant, while sorption of pyrene dropped sharply when the dispersant exceeded its critical micelle concentration (CMC). The deepwater conditions diminished the dispersant effects on solubilization, but enhanced uptake of the PAHs, albeit sorption of the dispersant was lowered. The information may aid in understanding roles of dispersants on distribution, fate and transport of petroleum PAHs in marine systems.

Electrochemical Stimulation of PAH Biodegradation in Sediment

Natural attenuation of PAH in sediments is usually slow due to prevailing anaerobic conditions in sediments. Electrochemical stimulation of PAH biodegradation is proposed and demonstrated for remediation of contaminated sediment. Two graphite electrodes were placed horizontally at different depths in PAH-spiked sediments; the cathode was near the water-sediment interface and the anode was laid in the deeper sediment. An external power of 2 V was continuously applied to the electrodes to stimulate PAH biodegradation. Redox potential around the anode in powered reactors increased gradually, and was 50–150 mV higher than that in the control. pH around the anode decreased to ∼6 from an initial value of 6.4 or 6.7 in powered reactors, which reflected water electrolysis. Phenanthrene concentration at the anode decreased with time, showing a unique Z-shaped profile in the sediment in powered reactors. PAH degrading genes around the anode in powered reactor were found to increase compared to the control reactor, which provided microbial evidence of biodegradation. These findings demonstrated the capability of this novel bioelectrochemical technology for the remediation of PAH-contaminated sediment.

Urban rivers as conveyors of hydrocarbons to sediments of estuarine areas: Source characterization, flow rates and mass accumulation

Aliphatic (n-C12–n-C40, unresolved complex mixture, resolved peaks) and aromatic hydrocarbons (46 PAH) were investigated in suspended particulate matter (SPM) sampled over eleven months in six of the major rivers and two channels of the Guanabara Bay Basin. PAH flow rates of the most contaminated rivers, the contribution to the PAH sediment load of the receiving bay, and the main sources of hydrocarbons were determined. PAH (38) ranged from 28ngL−1 to 11,514ngL−1. Hydrocarbon typology and statistical evaluation demonstrated contribution of distinct sources in different regions and allowed quantification of these contributions. Total flow rate for the five major rivers amounts to 3tyear−1 and responds for 30% of the total PAH annual input into the northern area of the Guanabara Bay. For the first time PAH mass deposited in the bay sediments has been estimated and shall serve as base for decision making and source abatement.

Component characteristics of polycyclic aromatic compounds in sediments of the South Mid-Atlantic Ridge

10 sample's of sediments obtained from the South Mid-Atlantic Ridge were measured for the abundances and distributions of polycyclic aromatic compounds (PAHs). The total concentrations of PAHs (Sigma PAHs) ranged from 2.768 to 9.826 mu g/g dry sediment. The Sigma PAHs was higher in sample 22V-TVG10 and sample 26V-TVG05 which were close to hydrothermal fields, with the lowest value in sample 22V-TVG14 which was farthest from hydrothermal fields, suggesting a probable hydrothermal origin of Sigma PAHs of samples. Approximately nine kinds of PAHs were identified, and low molecular mass tricyclic and tetracyclic aromatic compounds were predominant in the samples. The concentrations of fluoranthene which were typical as hydrothermal alteration compounds were the highest among PAHs with dry weight between 0.913-3.157 mu g/g. The phenanthrene homologue was most abundant in the samples, and the ratios between parent phenanthrene and methylphenanthrene which probably reflected the degree of hydrothermal alteration ranged from 0.097 to 1.602. The sample 22V-TVG10 possessing a maximum ratio value showed the intense influence of the hydrothermal alteration on this sample, which might further imply that PAHs in sediments were mainly derived from the hydrothermal alteration.

Polycyclic aromatic hydrocarbons in sediments from the Old Yellow River Estuary, China: Occurrence, sources, characterization and correlation with the relocation history of the Yellow River

The levels of 16 USEPA priority PAHs were determined in surface sediments and one dated sediment core from the abandoned Old Yellow River Estuary, China. Total PAH concentrations in the surface sediments ranged from 100.4 to 197.3ngg−1 dry weight and the total toxic equivalent quantity (TEQcarc) values of the carcinogenic PAHs were very low. An evaluation of PAH sources based on diagnostic ratios and principal component analysis suggested that PAHs in the surface sediments mainly derived from combustion sources. The total PAH concentrations altered significantly with year of deposition and showed quite different patterns of change compared with other studies: it is hypothesized that the principal cause of these changes is the relocation of the course of the Yellow River to the sea in 1976 and 1996.

An evaluation of background levels and sources of polycyclic aromatic hydrocarbons in naturally spawned embryos of Pacific herring (Clupea pallasii) from Puget Sound, Washington, USA

Pacific herring embryos spawned in nearshore habitats may be exposed to toxic contaminants as they develop, from exogenous sources in spawning habitats and from maternal transfer. Determining baseline concentrations of these toxic contaminants is important for evaluating the health of this species, especially during this sensitive life stage. In this study we compared concentrations of polycyclic aromatic hydrocarbons, or PAHs, in naturally spawned herring embryos from five spawning areas across Puget Sound. The summed values of 31 PAH analytes (Σ31PAH) in early- to late-stage development embryos ranged from 1.1 to 140ng/g, wet weight. Σ31PAH concentrations increased with development time in embryos from one spawning area where the greatest concentrations were observed, and the relative abundance of PAH chemicals in late-stage embryos was similar to those in nearby sediments, suggesting accumulation from local environmental sources. PAHs in both sediments and late-stage embryos appeared to exhibit a pyrogenic pattern. Although maternal transfer of PAHs appeared to be a negligible source to embryos in spawning areas with the greatest embryo PAH concentrations, maternal transfer may have been the dominant source in embryos from spawning areas where the lowest levels of embryo-PAHs occurred. Chronic embryo mortality has been reported in spawning habitats where we observed the greatest concentration of PAHs in embryos, and necrotic tissue in herring embryos from one such location was similar in description to phototoxic PAH necrosis reported elsewhere for embryonic zebrafish.

Polycyclic Aromatic Hydrocarbons Levels in Sediment, Benthic, Benthopelagic and Pelagic Fish Species from the Persian Gulf

In this study, three stations of the north Persian Gulf were analyzed in order to determinethe effect of trophic levels on the concentration of harmful PAHs in fish and sediment. In all cases,similar distributions were observed in which benzo(a)pyrene largely predominated andbenzo(b)fluoranthene and pyrene were the second major compounds in fish tissues. The predominantcomponents of PAHs in sediment were acenaphthene, pyrene and benzo(ghi)perylene. Based on themolecular weight of PAHs, the concentrations of the compounds vary among species. Netumabilineata, which is carnivorous, classified at a 0.49 to 3.8 trophic level and lives in association withsediment, accumulated the highest concentrations of high molecular weight PAHs, whereas L. abu,which is herbivorous and classified at a 0.2 to 2.6 trophic level, tended to accumulate low molecularweight PAHs. Comparison among the stations indicated that the fish and sediment from Tangestanestuary accumulated the highest levels of the compounds.

Sediment PAH: Contrasting levels in the Caspian Sea and Anzali Wetland

A comparative study of 23 PAH congeners in sediment of the Caspian Sea coast and Anzali Wetland was conducted in 2010. Surface sediment was analyzed using chromatography and mass spectrometry. Total PAH concentrations ranged between 212 and 9009ngg−1dw. Spatial distribution maps revealed that PAH levels were higher in the coastal areas of the Caspian Sea where oil related activities have been common since 1800’s. Diagnostic ratios analysis indicated that PAHs largely originated from petrogenic processes. PAH toxicity level was assessed using sediment quality guidelines and toxic equivalent concentrations to determine toxic effects on marine organism. Based on these investigations, in our study areas, the probability of toxicity for benthic organisms is “low to medium”. The toxic equivalent concentrations of carcinogenic PAHs varied between 11 and 231ng TEQ/g; higher total toxic equivalent concentrations values were found in the coastal areas of the Caspian Sea.

Carcinogenic and mutagenic potencies for different PAHs sources in coastal sediments of Shandong Peninsula

In this study, sources of PAHs in coastal sediments of Shandong Peninsula were apportioned using the chemical mass balance (CMB) model, and source apportionment of carcinogenic and mutagenic potencies was conducted combining CMB with the formula of benzo(a)pyrene carcinogenic equivalent (BaPTEQ) and BaP mutagenic equivalent (BaPMEQ) concentration. Total concentrations of sixteen PAHs in sediment ranged from 181.2ngg−1 to 303.6ngg−1, and concentrations of eight carcinogenic PAHs (cPAHs) varied from 98.8ngg−1 to 141.1ngg−1. The BaP played a dominant role for carcinogenic and mutagenic potencies of PAHs, although the IND showed the highest concentration level. The vehicular sources made the highest contribution to BaPTEQ (57.7%) and BaPMEQ (55.5%), while petrogenic source, the highest contributor for PAHs (39.4%), provided the lowest contribution to BaPTEQ (1.1%) and BaPMEQ (1.5%). Besides, the ecotoxicological evaluation, based on Sediment Quality Guidelines (SQGs), showed low ecological risks generally.

Chinese Arctic Yellow River Station Research Monitoring Program. 1. Polycyclic Aromatic Hydrocarbons in Sediment from Svalbard

Surface sediments of the west coast of Svalbard near Ny-Ålesund Spitsbergen were collected. PAHs of lake sediments (mean: 260, range: 11 - 1100 ng/g dry wt) were higher than previously report of surface lake sediment in Svalbard 1995, suggesting significant PAH contamination is occurring due to long-term atmospheric transport and local coal mining and fossil fuel sources, pointing to the role of Arctic lakes as potential reservoirs of semi-volatile organic compounds, including PAHs. Compound-specific analysis revealed different PAH patterns between Svalbard lakes and European high mountain lakes, showing higher proportions of low molecular weight compounds and lower levels of high molecular weight PAHs in Svalbard lakes. PAH indicator ratios suggest that the majority of PAHs in lake sediments have pyrogenic origins (coal mining, fossil fuel and biomass combustion), while coastal marine sediments were mainly contaminated by petroleum-derived PAHs (shipping activities in coastal areas, and perhaps as a result of an oil spill in 1986). Sediment fluxes of PAHs were estimated to be 0.2 - 22 ng cm-2yr-1. The current PAH levels exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies.

Petroleum hydrocarbon assessment in the wastewaters of petrochemical special economic zone and sediment benchmark calculation of the coastal area - northwest of the Persian Gulf

Petrochemical industries can potentially impact the environment due to their activities and products. This case study has considered adverse effects of petrochemical industries that are located inside the PETZONE with respect to the presence of polycyclic aromatic hydrocarbons and total petroleum hydrocarbon in wastewater effluents. The average concentrations of ∑PAHs group I and II were lower than the guideline values, thus the effluents of the study area can be considered unpolluted. Also, the average concentration of TPH was lower than the guideline value at all almost stations exceptthe effluent outlets of the Razi and Imam Khomeini petrochemical (BI-PC) companies which are proximal to Khowr-e Musa Bay. Thus, they may have an adverse impact on the aquatic ecosystem of the Bay. Therefore, the concentration of TPH was monitored in the sediments of the Bay (around the PETZONE coastal area) which wasrelatively moderate compared in the study area. Also, the sum ofChronic Potency Ratioof PAHs in sediments showed that the chronic benchmark was not more than the guideline at all stations (it is exceeded when the sum exceeds 1.0) except in the vicinity of the Aromatic effluent outlet of BI-PC.Thus, the chronic benchmark at this station indicates that it has the potential to cause a chronic effect on sediment-residence organisms like crabs, clams and worms. Moreover, PAHs concentration level in this station approached the NOAA sediment quality guideline value (ERL) of 4000 (ng/g dry weight).

Geochemical Evaluation of Thermal Maturity of the Cretaceous Sediments in the Calabar Flank based on the Distribution of the Polynuclear Aromatic Hydrocarbons

The thermal maturity parameter used in the evaluation of the hydrocarbon generative potential of the sedimentary organic matter is based largely on the extent of molecular transformation of the biological markers due to geothermal stress which is a function of depth or burial history. In particular the transformations leading to the formation of Polynuclear Aromatics usually occur at the end of diagenesis up to the onset of catagenesis. . An in-depth study of the transformation leading to the formation of polynuclear aromatic steroidal hydrocarbons revealed a step by step thermally mediated aromatization of the non-aromatic biogenic species during diagenetic/catagenetic evolution of organic matter in an anoxic environment. Since the formation of PAHs is a heat mediated process which increases with depth, then its concentration or the amount per unit mass of the rock sample can be used to estimate the thermal maturity of organic matter in the sediment .In light of the above, this work has evaluated the distribution profile of the PAHs in the Cretaceous sediments of the Calabar Flank using Gas Chromatograph interfaced to a Mass Spectrometer (GC-MS),an analytical tool combination widely used in the study of petroleum geochemistry. The results of the study based on the most dominant polynucear aromatic species namely, anthracene and phenanthrene revealed that Nkporo Shale(NS)samples from various locations in the Basin had a average PAH of 0.05mg/Kg (anthracene) and 0.06mg/Kg (phenanthrene).While the PAH value of Ekenkpon Shale(ES) samples was on the average 0.01mg/Kg and 0.02mg/Kg for anthracene and phenanthrene respectively. New Netim Marl(NNM) however gave the PAH value of only 0.001mg/Kg for phenanthrene and nil for anthracene .On the other hand Awi Sandstone (AS), Mfamosing Limestone (ML) and Nkporo Mudstone(NM) all fell within the non-detectable range. Based on the foregoing, PAH values can be used to evaluate the maturation level of organic matter in the sediments.

Characterization of parent and alkylated PAHs in surface sediments from Ría de Arousa (Galicia, NW Spain).

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Inferring sources for mercury to inland lakes using sediment chronologies of polycyclic aromatic hydrocarbons.

Sediment chronologies from inland lakes suggest the influence of local to sub-regional scale sources for mercury (Hg). However, apportionment of sources for Hg using sediment chronologies is difficult due to the mixing of sources and pathways. Mercury and polycyclic aromatic hydrocarbons (PAH) often share common sources and pathways into the environment. Thus, chronologies of PAHs in dated cores of sediments might be a useful tool to infer sources of Hg. Sediment cores from seven inland lakes of Michigan were collected for measurement of PAHs and Hg and dated by use of (210)Pb. PAH concentrations and ratios of kinetic and thermodynamic PAH compounds were used to infer sources of Hg. Ratios indicate the existence of modern combustion sources to each lake and historic combustion sources to lakes near cement kilns and an iron foundry. Coal combustion sources were identified for two lakes near urban centers. Whereas a petroleum combustion source was identified for a lake that has a coal fired power plant along its shoreline. These results have implications for the cycling of Hg on local to regional scales.

POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) IN COASTAL SEDIMENTS IN THE NORTH OF VIET NAM

Sediment samples were collected at 6 monitoring stations in the coastal area of North Viet Nam from Tra Co to Cua Lo station and were analysed to determinate PAHs contents. The analysic results shown that the content of total 8 PAHs were ranged from 69.56 to 183.88µg/kg dry weight. The content of total 8 PAHs was highest in Cua Lo station in the south, is lowest in Tra Co station in the north. Content of PAHs in dry season were higher than rainy season from 1.1 - 1.9 times. The content of PAHs were under the limitation, but Phenanthrene was exceeded the limitation from 1.02 - 2.66 times at all stations. Three - ring PAHs predominated and, occupied from 40.8 - 90.3 percents of total PAHs. The source of PAHs in coastal sediments in the North of Vietnam was from burning processes.

POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) IN COASTAL SEDIMENTS IN THE NORTH OF VIET NAM

Sediment samples were collected at 6 monitoring stations in the coastal area of North Viet Nam from Tra Co to Cua Lo station and were analysed to determinate PAHs contents. The analysic results shown that the content of total 8 PAHs were ranged from 69.56 to 183.88µg/kg dry weight. The content of total 8 PAHs was highest in Cua Lo station in the south, is lowest in Tra Co station in the north. Content of PAHs in dry season were higher than rainy season from 1.1 - 1.9 times. The content of PAHs were under the limitation, but Phenanthrene was exceeded the limitation from 1.02 - 2.66 times at all stations. Three - ring PAHs predominated and, occupied from 40.8 - 90.3 percents of total PAHs. The source of PAHs in coastal sediments in the North of Vietnam was from burning processes.

Evaluation five years after a Refinary Oil Spill in freshwater wetland - Paraná State, Southern of Brazil

In order to evaluate the Getúlio Vargas refinery oil spill - 2000, Paraná State - Brazil the presence of PAHs in the sediment, PAHs bioavailability through bile chemical analysis and biochemical and morphological biomarkers were investigated in a native fish species Hyphessobrycon reticulates. The histophatological parameters were also considered to another native species Phalloceros caudimaculatus. Sediment analysis showed the presence of 5-6 rings PAHs on the surface layer and 2-3 rings PAHs in the deepest sediment showing that oil is still accumulated in sediment, and its bioavailability is confirmed by the accumulation of PAHs in bile. Lipid peroxidation, catalase (CAT), GST and cholinesterase activities indicated respectively oxidative stress in liver of H. reticulatus and neurotoxicity, also evidenced by genotoxic and histopathological damages. Despite of the occurrence of other pollutants not identified in the current study, the data presented here may suggest that 5 years after the accident animals as fish can be still affected by hydrocarbons and PAHs presented in the sediment. Concluding, studies must be done to confirm that with a more sophisticated chemical analysis, but this work is the only study realized after the accident. We strongly suggest a new study to compare and verify if still there is risk to biota.

Understanding the Chronic Impacts of Oil Refinery Wastewater Requires Consideration of Sediment Contributions to Toxicity

Previous studies at an oil refinery in Saint John, New Brunswick, Canada, found a diminished fish community downstream of the effluent outfall that appeared to be associated with periodic low dissolved oxygen concentrations due to episodic discharges of contaminated transport vessel ballast water. This study was initiated after the ballast water was removed from the effluent to further investigate the potential causes of residual effects in the study stream, Little River. We used field caging of fish, laboratory bioassays, and chemical analysis of effluents and sediments from the field site to determine if the effluent or contaminated sediments were affecting the recovery of the fish community in Little River. The field studies suggested that exposed, caged fish were affected, displaying>40% increases in liver sizes and increased liver detoxification enzyme activity (cytochrome P450 1A, CYP1A); however, similar responses were absent in laboratory exposures that used effluent only. Adding sediments collected from the vicinity of the refinery's outfall to the laboratory bioassays reproduced some of the field responses. Chemical analyses showed high concentrations of PAHs in sediments but low concentrations in the effluent, suggesting that the PAHs in the sediment were contributing more to the impacts than the effluent. Application of effects-based monitoring is suggested as beneficial to identify impacts to fisheries where refinery effluents of this type are involved.

Coal-tar-based sealcoated pavement: A major PAH source to urban stream sediments

We used land-use analysis, PAH concentrations and assemblages, and multivariate statistics to identify sediment PAH sources in a small (∼1303 km2) urbanizing watershed located in South-Central, Pennsylvania, USA. A geographic information system (GIS) was employed to quantify land-use features that may serve as PAH sources. Urban PAH concentrations were three times higher than rural levels, and were significantly and highly correlated with combined residential/commercial/industrial land use. Principal components analysis (PCA) was used to group sediments with similar PAH assemblages, and correlation analysis compared PAH sediment assemblages to common PAH sources. The strongest correlations were observed between rural sediments (n = 7) and coke-oven emissions sources (r = 0.69–0.78, n = 5), and between urban sediments (n = 22) and coal-tar-based sealcoat dust (r = 0.94, n = 47) suggesting that coal-tar-based sealcoat is an important urban PAH source in this watershed linked to residential and commercial/industrial land use.