Prestige oil spill. III. Fate of a heavy oil in the marine environment

A new spatial estimation model and source apportionment of aliphatic hydrocarbons in coastal surface sediments of the Nayband Bay, Persian Gulf

Hydrocarbons, originating from oil and gas industries, are considered a potential risk for Nayband Bay, a natural marine park with extended mangroves, located on the north coastlines of the Persian Gulf, Iran. This paper determines the potential sources and spatial distribution of hydrocarbons, especially aliphatic hydrocarbons (AHCs), in Nayband Bay through the simultaneous application of three indices in the coastline surface sediments. To this end, a field study was conducted in the inter-tidal coastal zones and wetlands. Sediment samples were taken from surface layers along four transects with four sampling points at different distances from the gulf. The hydrocarbon compounds of the samples including AHCs, total petroleum hydrocarbons, and heavy metals (Ni, V as crude oil indicators) were analyzed and classified to discover the pollution indicators. Pearson pairwise correlation and cluster analyses along with pollution indices were employed to describe the spatial distribution pattern of hydrocarbons, identify hot spots, and determine the potential origin of AHCs. Different interpolation scenarios based on topographic and oceanic features were proposed to detect the spatial dynamics of AHCs. The results revealed that hydrocarbons mainly originated from anthropogenic sources including oil and gas industries located far from the affected area. It was also concluded that the long-distance pollution transfer was based on oceanic currents and wind direction in the bay. The proposed scenarios showed that the mean concentration values of total organic carbon and total organic material vary in the range 0.19 ppm to 0.4 ppm and 2.88 ppm to 3.20 ppm, respectively.

Comprehensive Two-Dimensional Gas Chromatography in Petroleum Derived Samples: A Review on Advances in Source and Weathering Studies of Spilled Oil

Since its introduction comprehensive two-dimensional gas chromatography (GC × GC) has been widely applied to analyze complex samples due to its enhanced peak capacity and selectivity, thereby increasing the number of identifiable peaks and improving coelution issues. Even though it is still undergoing development, GC × GC provides many advantages in the analysis of petroleum-derived samples, whether in reservoir geochemistry applications or in environmental studies associated with spilled oils. In general, it facilitates more thorough fingerprinting and compositional evaluation. In environmental studies, it helps enhance understanding of weathering processes and the environmental behavior of hydrocarbons, as its chromatographic retention indices can robustly estimate liquid vapor pressures, aqueous solubility and other physical chemical properties. This review presents a brief history of GC × GC instrumentation, discussing recent and significant advances in petroleum applications, from data handling techniques to reservoir geochemistry and environmental forensics, as well as some specific advantages achieved and certain limitations that continue to be encountered.

The interference of marine accidental and persistent petroleum hydrocarbons pollution on primary biomass and trace elements sink

More than 80 % of the primary biomass in marine environments is provided by phytoplankton. The primary mechanism in the trace element sink is the absorption of trace elements by phytoplankton. Because of their difficult degradability and bioaccumulation, petroleum hydrocarbons are one of the most significant and priority organic contaminants in the marine environment. This study chose Chlorella pyrenoidosa as the model alga to be exposed to short and medium-term petroleum hydrocarbons. The ecological risk of accidental and persistent petroleum hydrocarbon contamination was thoroughly assessed. The interaction and intergenerational transmission of phytoplankton physiological markers and trace element absorption were explored to reflect the change in primary biomass and trace element sink. C. pyrenoidosa could produce a large number of reactive oxygen species stimulated by the concentration and exposure time of pollutants, which activated their antioxidant activity (superoxide dismutase (SOD) activity, β-carotene synthesis, antioxidant trace elements uptake) and peroxides production (hydroxyl radicals and malondialdehyde). The influence of the growth phase on SOD activity, copper absorption, and manganese adsorption in both persistent and accidental pollution was significant (p < 0.05, F > Fα). Adsorption of manganese and selenium positively connected with SOD, malondialdehyde, and Chlorophyl-a (p < 0.01). These findings convincingly indicate that petroleum hydrocarbon contamination can interfere with primary biomass and trace element sinks.

Recent advances in chemical and biological degradation of spilled oil: A review of dispersants application in the marine environment

Growing concerns over the risk of accidental releases of oil into the marine environment have emphasized our need to improve both oil spill preparedness and response strategies. Among the available spill response options, dispersants offer the advantages of breaking oil slicks into small oil droplets and promoting their dilution, dissolution, and biodegradation within the water column. Thus dispersants can reduce the probability of oil slicks at sea from reaching coastal regions and reduce their direct impact on mammals, sea birds and shoreline ecosystems. To facilitate marine oil spill response operations, especially addressing spill incidents in remote/Arctic offshore regions, an in-depth understanding of the transportation, fate and effects of naturally/chemically dispersed oil is of great importance. This review provides a synthesis of recent research results studies related to the application of dispersants at the surface and in the deep sea, the fate and transportation of naturally and chemically dispersed oil, and dispersant application in the Arctic and ice-covered waters. Future perspectives have been provided to identify the research gaps and help industries and spill response organizations develop science-based guidelines and protocols for the application of dispersants application.

A review on physical remediation techniques for treatment of marine oil spills

There is a huge risk of contamination of water bodies due to the various oil exploration, transport, and industrial operational activities that are taking place across the world. Physical remediation techniques are considered extremely important for tackling the problems of marine oil spills. This paper provides a unique, specific review on the physical remediation of marine oil spills with special emphasis on types of available physical remediation techniques and their working principles. It also describes the chief latest improvements in the physical remediation techniques that have taken place with time. The paper discusses the various ways by which oil and its derivatives contaminate, and the subsequent effects these contaminants have on the marine ecosystem. The article discusses salient features that make physical remediation an effective marine oil spill counter-measure capable of recovering appreciable amounts of oil while causing minimal or no damage to the marine ecosystem and the workers carrying out the cleanup. Regarding the physical remediation methods, future research may focus on the development of hybrid booms, improved performance of skimmers for different oil types, and further applications involving novel materials like nanoparticles, zeolites for sorbents.

Effects of diesel oil spill on macrobenthic assemblages at the intertidal zone: A mesocosm experiment in situ

The oil spill accidents may drastically impact the environment and ecosystem at intertidal zones. The spilled oil will penetrate the sediments and accumulate to cause lethal or sublethal effects on the benthic invertebrates. An M-BACI experiment was manipulated in situ to assess the ecological responses of benthic macrofauna to different degrees of diesel oil spill. Both biotic and abiotic parameters were studied for 126 days, subjected to both "pulse" and "press" oil contaminations. The content of aliphatic hydrocarbons (displayed as ratios of n-C17/Pr and n-C18/Ph) slightly dropped then continuously existed in the sediment during the experiment time. The macrofaunal assemblage structures were dramatically altered in species number, abundance and biomass. In general, it takes longer time for the macrofauna assemblages to recover under high concentration oil spill than that under low concentration. Our results highlight the diversified strategies for survival and recolonization among dominant species, which distinguish themselves between: i) tolerant species, ii) opportunistic species, and iii) equilibrium species.

Imprint and short-term fate of the Agia Zoni II tanker oil spill on the marine ecosystem of Saronikos Gulf

In this study we investigate the spatial and temporal imprint of the September 2017 Agia Zoni II tanker heavy fuel oil spill on the marine ecosystem of Saronikos Gulf (Greece). Based on the chemical fingerprinting approach, by means of gas chromatography - flame ionization detector, gas chromatography-mass spectrometry and the use of various diagnostic ratios, we characterize changes in the composition of the spilled oil at various sampling sites and evaluate major mechanisms affecting its fate i.e. dissolution/dispersion, evaporation, biodegradation, photo-oxidation and sedimentation during the first six months from the spill. Overall, the main effects of the incident were confined to the coastal zone during the first three months after the spill, where an extended petroleum imprint was recorded in many cases, with the determined concentrations of the total petroleum hydrocarbons and polycyclic aromatic hydrocarbons falling within the highest range of concentrations previously reported for similar oil spill incidents worldwide. In the first three months following the spill the oil was affected by a combination of volatilization, rapid biodegradation and photodegradation, the later playing a role in its early days weathering. Concerning sediments, an imprint related to the incident was recorded in a few cases, being, however, mild in respect to the high chronic petroleum-associated anthropogenic background of the impacted area.

Petroleum Hydrocarbon-Degrading Bacteria for the Remediation of Oil Pollution Under Aerobic Conditions: A Perspective Analysis

With the sharp increase in population and modernization of society, environmental pollution resulting from petroleum hydrocarbons has increased, resulting in an urgent need for remediation. Petroleum hydrocarbon-degrading bacteria are ubiquitous in nature and can utilize these compounds as sources of carbon and energy. Bacteria displaying such capabilities are often exploited for the bioremediation of petroleum oil-contaminated environments. Recently, microbial remediation technology has developed rapidly and achieved major gains. However, this technology is not omnipotent. It is affected by many environmental factors that hinder its practical application, limiting the large-scale application of the technology. This paper provides an overview of the recent literature referring to the usage of bacteria as biodegraders, discusses barriers regarding the implementation of this microbial technology, and provides suggestions for further developments.

Use of porous materials to remove oil contaminants from water

The purpose of the research was to remove petroleum substances from water using porous materials. Birch bark, cork, glass wool and polyurethane foam were used for the study. The model solution was distilled water enriched with a mixture of petrol and diesel fuel in a volume ratio of 1:3. The model water used had 3 different concentrations of oil substances. The research included petroleum substances expressed as mineral oil index and aliphatic hydrocarbons, n-alkanes (from C7H16 to C38H78). The process of oil substances removal was carried out applying two methods: static and dynamic. Based on the research, it was found that materials the most effective in lowering the index of mineral oil and C7H16-C38H78 n-alkane concentrations were both birch bark and glass wool, both static and dynamic, while cork and polyurethane foam were less effective. In addition, concentration of C7H16-C38H78 n-alkanes was lowered in each measurement series to a greater extent than the mineral oil index.

Oil spill off the coast of Guimaras Island, Philippines: Distributions and changes of polycyclic aromatic hydrocarbons in shellfish

The sinking of the Solar 1 tanker caused serious heavy oil pollution around Guimaras Island, Philippines. In the present study, variations of parent polycyclic aromatic hydrocarbons (PAHs) and alkylated PAHs (alkPAHs) in some shellfish were investigated around Guimaras Island and other small islands from 3months to 5years after the spill. The total PAHs and alkPAHs in shellfish were detected in high concentrations at 448 and 33,666ng/g dry weight, respectively, in November 2006. The concentrations of alkPAHs gradually decreased, while the parent PAHs in shellfish degraded more slowly than the alkPAHs, which was likely due to the persistent characteristics of PAHs. The risks based on European Union regulations were insignificant in 2008, but total PAHs in shellfish were still over 8 times higher at the investigated sites in November 2011 than that before the oil spill.

Identifying the source of petroleum pollution in sediment cores of southwest of the Caspian Sea using chemical fingerprinting of aliphatic and alicyclic hydrocarbons

In this study, the concentration and sources of aliphatic and petroleum markers were investigated in 105 samples of Anzali, Rezvanshahr and Astara cores from the southwest of Caspian Sea. Petroleum importation was diagnosed as a main source in most depths of cores by the results of unresolved complex mixture, carbon preference index and hopanes and steranes. From the chemical diagnostic parameters, petroleum inputs in sediment of cores were determined to be different during years and the sources of hydrocarbons in some sections differed than Anzali and Turkmenistan and Azerbaijan oils. Diagenic ratios in most sediments of upper and middle sections in Astara core were determined to be highly similar to those of Azerbaijan oil, while the presence of Turkmenistan and Anzali oils were detected in a few sections of Anzali and Rezvanshahr cores and only five layers of downer section in Anzali core, respectively.

Identification of sources of tar balls deposited along the Southwest Caspian Coast, Iran using fingerprinting techniques

In 2012, a significant number of tar balls occurred along the Southwest coasts of the Caspian Sea (Iran). Several oil fields of Turkmenistan, Azerbaijan and Iran might be sources of oil spills and lead to the formation of these tar balls. For source identification, 6 tar ball samples were collected from the Southwest beaches of the Caspian Sea and subjected to fingerprint analysis based on the distribution of the source-specific biomarkers of pentacyclic tri-terpanes and steranes. Comparing the diagenic ratios revealed that the tar balls were chemically similar and originated from the same source. Results of double ratio plots (e.g., C29/C30 versus ∑C31-C35/C30 and C28 αββ/(C27 αββ+C29 αββ) versus C29 αββ/(C27 αββ+C28 αββ)) in the tar balls and oils from Iran, Turkmenistan and Azerbaijan indicated that the tar balls might be the result of spills from Turkmenistan oil. Moreover, principle component analysis (PCA) using biomarker ratios on the tar balls and 20 crude oil samples from different wells of Azerbaijan, Iran and Turkmenistan oils showed that the tar balls collected at the Southwest beaches are highly similar to the Turkmenistan oil but one of the Azerbaijan oils (from Bahar field oils) was found to be also slightly close to the tar balls. The weathering characterizations based on the presence of UCM (unresolved complex mixture) and low/high molecular weight ratios (L/H) of alkanes and PAHs indicated the tar ball samples have been significantly influenced by natural weathering processes such as evaporation, photo-degradation and biodegradation. This is the first study of its kind in Iran to use fingerprinting for source identification of tar balls.

The effect of oil spills on the bacterial diversity and catabolic function in coastal sediments: a case study on the Prestige oil spill

The accident of the Prestige oil tanker in 2002 contaminated approximately 900 km of the coastline along the northern Spanish shore, as well as parts of Portugal and France coast, with a mixture of heavy crude oil consisting of polycyclic aromatic hydrocarbons, alkanes, asphaltenes and resins. The capacity of the autochthonous bacterial communities to respond to the oil spill was assessed indirectly by determining the hydrocarbon profiles of weathered oil samples collected along the shore, as well as through isotope ratios of seawater-dissolved CO2, and directly by analyses of denaturing gradient gel electrophoresis fingerprints and 16S rRNA gene libraries. Overall, the results evidenced biodegradation of crude oil components mediated by natural bacterial communities, with a bias towards lighter and less substituted compounds. The changes observed in the Proteobacteria, the most abundant phylum in marine sediments, were related to the metabolic profiles of the sediment. The presence of crude oil in the supratidal and intertidal zones increased the abundance of Alpha- and Gammaproteobacteria, dominated by the groups Sphingomonadaceae, Rhodobacteraceae and Chromatiales, whilst Gamma- and Deltaproteobacteria were more relevant in subtidal zones. The phylum Actinobacteria, and particularly the genus Rhodococcus, was a key player in the microbial response to the spill, especially in the degradation of the alkane fraction. The addition of inorganic fertilizers enhanced total biodegradation rates, suggesting that, in these environments, nutrients were insufficient to support significant growth after the huge increase in carbon sources, as evidenced in other spills. The presence of bacterial communities able to respond to a massive oil input in this area was consistent with the important history of pollution of the region by crude oil.

GC-MS analysis of two types of mixed oils, a comparison of composition and weathering patterns

In order to compare the effects of weathering on two types of mixed oil, simulated weathering experiments were performed. The first sample was a mixture of two fresh oils and the second sample was a mixture of one fresh oil and another oil sample that had undergone a serious weathering process. Comparative studies evaluated decay rates and changes in diagnostic ratios of some fingerprinting biomarkers. Results showed that the mixing process affected the weathering rate of some compounds in the oils and also that certain diagnostic ratios are more suitable for estimating mixing proportions. A Pr/n-C17 versus Ph/n-C18 plot can be used to identify the end-numbers of mixed oils and the (C13+C14)/(C25+C26) ratio is a useful diagnostic ratio to detect the degree of weathering. Finally, hopane, sterane, and alkylated PAH fingerprints were found to give useful insights about the sources of the mixed oils.

Marine Oil-Degrading Microorganisms and Biodegradation Process of Petroleum Hydrocarbon in Marine Environments: A Review

Due to the toxicity of petroleum compounds, the increasing accidents of marine oil spills/leakages have had a significant impact on our environment. Recently, different remedial techniques for the treatment of marine petroleum pollution have been proposed, such as bioremediation, controlled burning, skimming, and solidifying. (Hedlund and Staley in Int J Syst Evol Microbiol 51:61-66, 2001). This review introduces an important remedial method for marine oil pollution treatment-bioremediation technique-which is considered as a reliable, efficient, cost-effective, and eco-friendly method. First, the necessity of bioremediation for marine oil pollution was discussed. Second, this paper discussed the species of oil-degrading microorganisms, degradation pathways and mechanisms, the degradation rate and reaction model, and the factors affecting the degradation. Last, several suggestions for the further research in the field of marine oil spill bioremediation were proposed.

Recovery of a subtropical rocky shore is not yet complete, four years after a moderate sized oil spill

Little is known about the recovery trajectory from small to moderate spills (<1000 t), particularly in the sub-tropics. On 11 March 2009 the MV Pacific Adventurer spilt 270 t of bunker fuel oil 13 km off Moreton Island, Australia, impacting wetlands, sandy beaches and rocky shores. This study examines the recovery of the rocky shore community four years after the spill. Results indicate that recovery on Moreton Island is taking longer than the 3-4 years suggested by the literature. The upper shore is recovering faster than the mid shore and is nearly recovered while the mid shore is still in the recovery process. These results indicate that small to moderate sized spills can have environmental impacts on par with much larger spills and emphasizes the need for a clear definition of a recovery endpoint. Long term studies are required to gain a full understanding of trajectories of recovery after oil spill impacts.

Biosurfactant production from marine hydrocarbon-degrading consortia and pure bacterial strains using crude oil as carbon source

Biosurfactants (BSs) are "green" amphiphilic molecules produced by microorganisms during biodegradation, increasing the bioavailability of organic pollutants. In this work, the BS production yield of marine hydrocarbon degraders isolated from Elefsina bay in Eastern Mediterranean Sea has been investigated. The drop collapse test was used as a preliminary screening test to confirm BS producing strains or mixed consortia. The community structure of the best consortia based on the drop collapse test was determined by 16S-rDNA pyrotag screening. Subsequently, the effect of incubation time, temperature, substrate and supplementation with inorganic nutrients, on BS production, was examined. Two types of BS - lipid mixtures were extracted from the culture broth; the low molecular weight BS Rhamnolipids and Sophorolipids. Crude extracts were purified by silica gel column chromatography and then identified by thin layer chromatography and Fourier transform infrared spectroscopy. Results indicate that BS production yield remains constant and low while it is independent of the total culture biomass, carbon source, and temperature. A constant BS concentration in a culture broth with continuous degradation of crude oil (CO) implies that the BS producing microbes generate no more than the required amount of BSs that enables biodegradation of the CO. Isolated pure strains were found to have higher specific production yields than the complex microbial marine community-consortia. The heavy oil fraction of CO has emerged as a promising substrate for BS production (by marine BS producers) with fewer impurities in the final product. Furthermore, a particular strain isolated from sediments, Paracoccus marcusii, may be an optimal choice for bioremediation purposes as its biomass remains trapped in the hydrocarbon phase, not suffering from potential dilution effects by sea currents.

Source characterization of polycyclic aromatic hydrocarbons by using their molecular indices: an overview of possibilities

In recent decades. an exponential increase in the concentration of anthropogenic Polycyclic Aromatic Hydrocarbons (PAHs; see Table I for a li st of PAH abbreviations) has been observed worldwide. Regulators need to know the sources if concentrations are to be reduced and appropriate remediation measures taken. "Source characterization of PAHs" involves linking these contaminants to their sources. Scientists place PAH sources into three classes: pyrogenic, petrogenic. and natural. In this review. we investigate the possibility of using PAH molecular ratios individually or in combination for the purpose of deducing the petrogenic or pyrogenic origin of the contamination in sediments. We do this by reviewing the characteristic PAH patterns of the sources and by taking into account the fate of PAHs in the aquatic environment. Many PAH indicators have been developed for the purpose of discriminating different PAH sources. In Table 4 we summarize the applicability of different PAH ratios and threshold values. The analysis of two- to four-ringed alkylated PAH soilers the possibility to distinguish two or more single sources or categories of pollution in greater detail. For example. the FLO/PYO. the PPI. and PO/AO ratios can be used to discriminate between pyrogenic and petrogcnic sources of contamination. When petrogenic contamination is suspected. chrysenes. PAHs lighter than CO. and in particular. alkylated PAHs can usually be of use. For unburned coal PAHs. The methylphenanthrenic ratios (MP!s). the 1-D I/4- DI. and BbF/BkF are promising, since they are sometimes correlated with vitrinite rellectance (coal ranks). Alkylphenanthrenes can be used to detect biomass combustion. Higher molecular weight parent and alkylated PAHs are appropriate for pyrogenic discriminations. When PAH indices are coupled with discriminant analysis techniques such as PMF (positive matrix factorization),the origin of multiple sources in even the most complex environments can be traced and measured. Even so. the most stable isomer pairs degrade differentially. depending on their thermodynamic stability, the environmental conditions, and the type of degradation. If PAH ratios are to be used, it is usually necessary to have pri or knowledge of the degradation state of the matrices examined (air, sediment, etc.) and of how the PAH ratio behaves under such conditions. PAH ind ices (e.g ., NO/CO or LPAH/HPAH ) can be app lied for distinguishing differential degradation gradients (photodegradation, biodegradation, etc.). Degradation does not significantly affect the ratio of parent to alkylated PAHs and the PI. The degradation arrow in Table 4 and Figs. 9. I 0. II . 12. 13, 14. 15. 17. 18. 19, 20, 2 1, 22. 23. and 24 shows how the ratio usually changes with degradation. Merely detecting the six PAHs of Borneff6 is not enough to establish petrogenic contamination, because Borneff6 includes main ly HMW PAHs. The LPAH 16 appears to be the most suitable for identify ing pyrogenic and petrogenic sources. For more specific information on sources and their discrimination it is recommended to further take into account important parent PAHs such as NO. BeP. PER. DO. and-most importantly- alkylatcd PAHs.

Halophyte plant colonization as a driver of the composition of bacterial communities in salt marshes chronically exposed to oil hydrocarbons

In this study, two molecular techniques [denaturing gradient gel electrophoresis (DGGE) and barcoded pyrosequencing] were used to evaluate the composition of bacterial communities in salt marsh microhabitats [bulk sediment and sediment surrounding the roots (rhizosphere) of Halimione portulacoides and Sarcocornia perennis ssp. perennis] that have been differentially affected by oil hydrocarbon (OH) pollution. Both DGGE and pyrosequencing revealed that bacterial composition is structured by microhabitat. Rhizosphere sediment from both plant species revealed enrichment of operational taxonomic units closely related to Acidimicrobiales, Myxococcales and Sphingomonadales. The in silico metagenome analyses suggest that homologous genes related to OH degradation appeared to be more frequent in both plant rhizospheres than in bulk sediment. In summary, this study suggests that halophyte plant colonization is an important driver of hydrocarbonoclastic bacterial community composition in estuarine environments, which can be exploited for in situ phytoremediation of OH in salt marsh environments.

Quantification of 21 metabolites of methylnaphthalenes and polycyclic aromatic hydrocarbons in human urine

Polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives, such as methylnaphthalenes (MeNs), are harmful pollutants ubiquitously present in the environment. Exposure to PAHs has been linked to a variety of adverse health effects and outcomes, including cancer. Alkyl PAHs have been proposed as petrogenic source indicators because of their relatively high abundance in unburned petroleum products. We report a method to quantify 11 urinary methylnaphthols (Me-OHNs), metabolites of 1- and 2-methylnaphthalenes, and 10 monohydroxy PAH metabolites (OH-PAHs), using automated liquid-liquid extraction and isotope dilution gas chromatography tandem mass spectrometry (GC-MS/MS). After spiking urine (1 mL) with (13)C-labeled internal standards, the conjugated target analytes were hydrolyzed enzymatically in the presence of ascorbic acid. Then, their free species were preconcentrated into 20 % toluene in pentane, derivatized and quantified by GC-MS/MS. The 11 Me-OHNs eluted as 6 distinct chromatographic peaks, each representing 1 - 3 isomers. Method detection limits were 1.0- 41 pg/mL and the coefficients of variation in quality control materials were 4.7 - 19 %. The method was used to analyze two National Institute of Standards and Technology's Standard Reference Materials® and samples from 30 smokers and 30 non-smokers. Geometric mean concentrations were on average 37 (Me-OHNs) and 9.0 (OH-PAHs) fold higher in smokers than in non-smokers. These findings support the usefulness of Me-OHNs as potential biomarkers of non-occupational exposure to MeNs and sources containing MeNs.

Assessment of photochemical processes in marine oil spill fingerprinting

Understanding weathering processes plays a critical role in oil spill forensics, which is based on the comparison of the distributions of selected compounds assumed to be recalcitrant and/or have consistent weathering transformations. Yet, these assumptions are based on limited laboratory and oil-spill studies. With access to additional sites that have been oiled by different types of oils and exposures, there is a great opportunity to expand on our knowledge about these transformations. Here, we demonstrate the effects of photooxidation on the overall composition of spilled oils caused by natural and simulated sunlight, and particularly on the often used polycyclic aromatic hydrocarbons (PAHs) and the biomarker triaromatic steranes (TAS). Both laboratory and field data from oil released from the Macondo well oil following the Deepwater Horizon disaster (2010), and heavy fuel-oil from the Prestige tanker spill (2002) have been obtained to improve the data interpretation of the typical fingerprinting methodology.

Enhancing the biodegradation of oil in sandy sediments with choline: a naturally methylated nitrogen compound

We investigated how additions of choline, a naturally occurring methylated nitrogen-containing compound, accelerated hydrocarbon degradation in sandy sediments contaminated with moderately weathered crude oil (4000 mg kg(-1) sediment). Addition of lauroylcholine chloride (LCC) and tricholine citrate (TCC) to oil contaminated sediments resulted in 1.6 times higher hydrocarbon degradation rates compared to treatments without added choline derivatives. However, the degradation rate constant for the oil contaminated sediments amended with LCC was similar to that in contaminated sediments amended with inorganic nitrogen, phosphorus, and glucose. Additions of LLC and TCC to sediments containing extensively weathered oil also resulted in enhanced mineralization rates. Cultivation-free 16S rRNA analysis revealed the presence of an extant microbial community with clones closely related to known hydrocarbon degraders from the Gammaproteobacteria, Alphaproteobacteria, and Firmicutes phyla. The results demonstrate that the addition of minimal amounts of organic compounds to oil contaminated sediments enhances the degradation of hydrocarbons.

Recurrent arrival of oil to Galician coast: the final step of the Prestige deep oil spill

Yearly monitoring in one of the most affected coastal zones by the Prestige oil spill, namely Nemiña and O Rostro beaches (NW Spain), has been carried out since 2004. Topographic data of beaches revealed seasonal altimetric changes up to 4m that would prevent the on shore persistence of oil. However, surficial and subsurficial oil was detected in the intertidal area of both beaches in all campaigns. The hydrocarbon analysis confirmed that this oil corresponded to the Prestige oil, even nine years after the accident. Tar balls were highly biodegraded suggesting that the oil was accumulated on the subtidal sediments for a long time and transported to the coast by the action of waves. The present work provides new evidence of the long term persistence of deep oil spills from wrecks in marine areas where the hydrodynamic conditions play a twofold key role, in determining the exposed coastal area to recurrent contamination and in burying and resurfacing the oil in the intertidal zone.

The use of long-chain alkylbenzenes and alkyltoluenes for fingerprinting marine oil wastes

Petroleum long-chain alkylbenzenes and alkyltoluenes are characterized and used for chemical fingerprinting of marine oil spills. Their distributions, extending from C10 to C35 can be used for a general oil type classification. Moreover, the relative distributions of specific components, namely the 3-methyl and 2-methyl-1-alkylbenzenes (m- and o-isomers), and the aryl isoprenoid 1-methyl-3-phytanylbenzene, are proposed as diagnostic markers for source identification. This approach has been exemplified in two case studies involving the spill of bilge oils, where a preliminary screening of the potential source was obtained.

Mesocosm study on weathering characteristics of Iranian Heavy crude oil with and without dispersants

The environmental fate of Iranian Heavy crude oil (IHC) with and without an added oil spill dispersant (OSD) has been studied using a 1000 kL capacity in situ mesocosm. Physical weathering and chemical composition changes of the oil were monitored for 77 days. Compound-specific effects of the OSD could be observed as changes over time in the content of the total petroleum hydrocarbon (TPH), unresolved complex mixture (UCM), alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes and steranes in the oil. As oil weathers, most hydrocarbons showed a rapid decreasing phase followed by a slowdown and stabilization. Recalcitrant biomarkers, however, showed a different trend. An increase in hydrocarbon contents in the form of UCM occurred after OSD treatment. The enhanced solubility of the low molecular weight PAHs by the OSD decreased the half-life of the alkylated PAHs in the OD. After 77 days of exposure at the sea surface, both the oils with and without the OSD exhibited moderate weathering. Most of the source diagnostic indices maintained their source information, and the weathering indices indicated that evaporation, dissolution, and dispersion were the major weathering processes. The mass balance of the weathered oil was calculated using laboratory and mesocosm data and the results demonstrate the importance of using a mesocosm for the production of environmentally realistic data.

Marine organic pollutants of the Eastern Aegean: aliphatic and polycyclic aromatic hydrocarbons in Candarli Gulf surficial sediments

Aliphatics and PAHs were determined in sediments from the Candarli Gulf in 2009. Aliphatics ranged from 3.88 to 24.7 μg g(-1) while aromatics varied between <4.15 and 405 ng g(-1) (dw). PAHs ranged from a relatively low to a moderate PAHs pollution compared to other urbanized coastal areas worldwide. 3-ring PAHs were most abundant in the sampling area. Both pyrolytic and petrogenic PAHs were present in most samples, although petroleum derived PAHs were dominant at the stations situated near the refinery and petrochemical, metal industry and pyrolytic sources were mainly prevalent in the estuary of Bakircay River. The ratio of UCM to n-alkanes and CPI values in station 6 indicate that the main contribution to petroleum hydrocarbon contamination is via oil and its products. PAH levels at all sites were below the ERL and ERM except fluorene. The results indicated that the sediments should have no potential biological impact except stations 6 and 14.

Post-incident monitoring to evaluate environmental damage from shipping incidents: chemical and biological assessments

Oil and chemical spills in the marine environment are an issue of growing concern. Oil exploration and exploitation is moving from the continental shelf to deeper waters, and to northern latitudes where the risk of an oil spill is potentially greater and may affect pristine ecosystems. Moreover, a growing number of chemical products are transported by sea and maritime incidents of hazardous and noxious substances (HNS) are expected to increase. Consequently, it seems timely to review all of the experience gained from past spills to be able to cope with appropriate response and mitigation strategies to combat future incidents. Accordingly, this overview is focused on the dissemination of the most successful approaches to both detect and assess accidental releases using chemical as well as biological approaches for spills of either oil or HNS in the marine environment. Aerial surveillance, sampling techniques for water, suspended particles, sediments and biota are reviewed. Early warning bioassays and biomarkers to assess spills are also presented. Finally, research needs and gaps in knowledge are discussed.

Review of oil and HNS accidental spills in Europe: identifying major environmental monitoring gaps and drawing priorities

The European Atlantic area has been the scene of a number of extensive shipping incidents with immediate and potential long-term impacts to marine ecosystems. The occurrence of accidental spills at sea requires an effective response that must include a well executed monitoring programme to assess the environmental contamination and damage of the affected marine habitats. Despite a number of conventions and protocols developed by international and national authorities that focused on the preparedness and response to oil and HNS spills, much remains to be done, particularly in relation to the effectiveness of the environmental monitoring programmes implemented after oil and HNS spills. Hence, the present study reviews the status of the environmental monitoring programmes established following the major spill incidents over the last years in European waters, aiming at identifying the key monitoring gaps and drawing priorities for an effective environmental monitoring of accidental spills.

Sources and distribution of aliphatic and polyaromatic hydrocarbons in coastal sediments from the Ushuaia Bay (Tierra del Fuego, Patagonia, Argentina)

The environmental quality of Ushuaia Bay, located at the southernmost tip of South America, is affected by the anthropogenic pressure of Ushuaia city. In this study, levels and sources of hydrocarbons in coastal sediments were assessed. Aliphatic hydrocarbon fractions ranged between 5.5 and 1185.3 μg/g dry weight and PAHs from not detected to 360 ng/g. Aliphatic diagnostic indices, the nalkanes homologous series occurrence, Aliphatic Unresolved Complex Mixtures (AliUCMs), and pristane and phytane isoprenoids indicated a petrogenic input. Some sites showed biogenic features masked by the anthropogenic signature. Particularly in port areas biodegradation processes were evident. PAH ratios showed a mixture of petrogenic and pyrogenic sources. Aliphatic and aromatic UCMs were strongly correlated, reflecting chronic pollution. Three areas were distinguished inside the bay: (1) east, with low hydrocarbons impact; (2) central, where hydrocarbons accumulation was related to source proximity and sediment characteristics; (3) south-west, where sediment characteristics and current circulation favour hydrocarbons accumulation.

Aliphatic and polycyclic aromatic hydrocarbons in the surface sediments from the Eastern Aegean: assessment and source recognition of petroleum hydrocarbons

MATERIALS AND METHODS

Aliphatic and polycyclic aromatic hydrocarbons (PAHs) were determined in surficial sediments from the Aegean Sea in the Eastern Mediterranean in 2008.

RESULTS

Total aliphatic hydrocarbons (n-C12 to n-C35) ranged from 330 to 2,660 ng g(-1) dry weight (dwt), while aromatics (19 PAHs) varied between 73.5 and 2,170 ng g(-1) dwt. Total concentrations of both aliphatic hydrocarbons and PAHs ranged from a relatively low to a moderate PAHs pollution compared to other urbanized coastal areas worldwide. PAH consisted mainly of pyrolytic four- to five-ring compounds. Both pyrolytic and petrogenic PAHs are present in most samples, although petroleum-derived PAH are dominant at Izmir Inner Bay (IIB) and Dardanelles Strait, and pyrolytic sources are prevalent in other sampling sites. A high contribution of perylene, a diagenetic originated PAH, to the total penta PAHs was found greater than 70% in Meric River Estuary, Dikili Bay, Candarli Bay, and Gokova Bay sites.

CONCLUSION

The spatial distributions of aliphatic hydrocarbons and PAHs indicated that urban runoff and transport from the continental shelf is the major input pathway of anthropogenic and biogenic hydrocarbons from terrestrial sources in the near-shore area. PAH levels at all sites were below the effects range-low (ERL) and effects range-median (ERM) values except fluorene. The average and maximum fluorene concentrations exceeded ERL, but below ERM, in the IIB. Meanwhile, the concentration levels of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, benzo[a]anthracene, and chrysene were higher than threshold effect level values at the same site, but all these compounds were significantly lower than the probable effect level values. The results indicated that the sediments should have potential biological impact.

Health status of Pomatoschistus microps populations in relation to pollution and natural stressors: implications for ecological risk assessment

Effects induced on wild populations by recurrent environmental contamination may difficult the ecological risk assessment of punctual pollution events such as oil spills. Here, the issue was addressed by comparing the health status of Pomatoschistus microps populations from four NW Iberian estuaries, using an integrated chemical-biological monitoring. Despite high seasonal variability, the parameters measured discriminated estuaries with different contamination levels and associated biological effects with chemical and abiotic stress. The decreased health status of fish from polluted sites strengthens the need of considering pollution-induced background effects and seasonal variability when assessing impacts and risks of oil and other chemical spills.

Fingerprint and weathering characteristics of stranded oils after the Hebei Spirit oil spill

After the Hebei Spirit oil spill in December 2007, mixtures of three types of Middle East crude oil were stranded along 375 km of coastline in Western Korea. Stranded oils were monitored for their identity and weathering status in 19 stations in three provinces. The results obtained using a weathering model indicated that evaporation would be a dominant weathering process immediately after the spill and the sequential changes of chemical composition in the field verified this prediction positively. In the early stages of weathering, the half-life of spilled oil was calculated to be 2.6 months. Tiered fingerprinting approaches identified background contamination and confirmed the identity of the stranded oils with the spill source. Double ratios using alkylated phenanthrenes and dibenzothiophenes in samples after the spill clearly reveal the impact of weathering on oil. However, to derive defensible fingerprinting for source identification and allocation, recalcitrant biomarkers are extremely useful. Weathering status of the stranded oils was evaluated using composition profiles of saturated hydrocarbons, polycyclic aromatic hydrocarbons and various weathering indices. Most samples collected 8 months after the spill were categorized in either the advanced or extreme weathering states. Gradual increase in toxic components in the residual oil through weathering emphasizes the need for adaptive ecotoxicological approaches.

The M/V Cosco Busan spill: source identification and short-term fate

Understanding the fate of heavy fuel oils (HFOs) in the environment is critical for sound decisions regarding its usage and spill cleanup. To study weathering of HFOs, we examined the M/V Cosco Busan spill (November 2007; San Francisco Bay, CA, USA). In this baseline report, we identified which ruptured tank (port tank 3 or 4) was the source of the spilled oil and characterized changes in the oil composition across location and time. Samples from three impacted shorelines, collected within 80 days of the spill, were analyzed using one- and two-dimensional gas chromatography (GC and GC × GC, respectively). Weathering varied across sites, but compounds with GC retention times less than n-C(16) were generally lost by evaporation and dissolution. Changes in n-C(18)/phytane and benz[a]anthracene/chrysene ratios indicated some biodegradation and photodegradation, respectively.

Phase distribution of hydrocarbons in the water column after a pelagic deep ocean oil spill

Spills from wrecks are a potential major source of pollution in the deep ocean. However, not much is known about the fate of a spill at several kilometers depth, beyond the oceans continental shelves. Here, we report the phase distribution of hydrocarbons released from the wrecks of the Prestige tanker, several years after it sank in November 2002 to depths between 3500 and 3800 m. The released oil reached the surface waters above the wrecks without any signs of weathering and leaving an homogenous signature throughout the water column. At depths of several kilometers below the sea surface, the occurrence and spread of the deep sea oil spill could be evaluated better by quantifying and characterizing the dissolved hydrocarbon signature, rather than just the investigation of hydrocarbons in the suspended particulate matter.

Simulating the influence of physicochemical parameters on subsurface oil on beaches: preliminary results

Monitoring of sandy beaches after the Prestige oil spill revealed thick subsurface layers (up to 1m thick) of grey-coloured sand. These horizons were sometimes found under more than 3m of clean sand. Examination of the sand by electron microscopy confirmed that the colouring was due to oil-coated sand grains, and revealed a sequence of degradation of buried oil. Further analysis of the sand revealed high concentrations of hydrocarbon in the oil-coated sand and that the main biomarkers were indicative of biodegradation, even though the oil was buried. A set of experiments was designed to analyze the evolution of oil from tar balls to coatings. The results revealed that biodegradation is a secondary process in the changes that take place in the buried oil, and that water flow slows down the appearance of grey sand and that low salinity may hinder the oil degradation process.

Environmental implications of oil spills from shipping accidents

Since ancient times, ships have sunk during storms, either as a result of collisions with other vessels or running onto rocks. However, the ever-increasing importance of crude oil in the twentieth century and the corresponding growth in the world's tanker fleet have drawn attention to the negative implications of sea transport. Disasters involving tankers like the Torrey Canyon or the Amoco Cadiz have shown how dramatic the consequences of such an accident may be. The effects of oil spills at sea depend on numerous factors, such as the physicochemical parameters of the oil, the characteristics of the environment affected, and the physical, chemical, and biological processes occurring there, such as evaporation, dissolution, dispersion, emulsification, photo-oxidation, biodegradation, and sedimentation. The combination of these processes reduces the concentrations of hydrocarbons in sediments and water and alters the chemical composition of spilled oils. In every case, oil spills pose a danger to fauna and flora and cause damage to sea and shores ecosystems. Many of the petroleum-related chemicals that are spilled are toxic, otherwise carcinogenic or can be bioaccumulated in the tissues of marine organisms. Such chemicals may then be biomagnified up the marine food chain from phytoplankton to fish, then to seals and other carnivorous sea mammals. Moreover, oil products can be accumulated and immobilized in bottom deposits for long periods of time. Oil spills are particularly dangerous when they occur in small inland seas that have intense sea traffic, e.g., the Baltic Sea.

Inputs and sources of hydrocarbons in sediments from Cienfuegos bay, Cuba

The spatial distribution of aliphatic and polycyclic aromatic hydrocarbons (PAHs) was investigated in sediments from the Cienfuegos bay. The highest anthropogenic hydrocarbon inputs were found near the city of Cienfuegos with an unresolved complex mixture (UCM) of aliphatic hydrocarbons and alkylated PAHs, indicative of petrogenic inputs. Parent PAHs, which are typical of high-temperature combustion processes, were evenly distributed in the whole basin and largely prevailing in the southern part of the Cienfuegos city. Biomarker fingerprints assign the sources of pollution to mixes of national and non-national crude oils. The overall levels of anthropogenic hydrocarbons are relatively high compared to relevant areas worldwide and reveal a moderate/high level of hydrocarbon pollution. The Cienfuegos bay sediments received over a period of 5 yr, 50 T/yr of petrogenic unresolved hydrocarbons (UCM) and 2 T/yr of PAHs, being deposited the 80% in the sediments of the north basin.

Assessment of cleanup needs of oiled sandy beaches: lessons from the Prestige oil spill

Surveys of the oiled sandy beaches along the northern Atlantic coast of Spain, 2-5 years after the Prestige oil spill of November 2002, have provided new evidence regarding buried fuel and its behavior. The persistence and depth of burial of oil, and the capacity of the beach for natural regeneration, depend on beach morphodynamics, which drive a sequence of physicochemical processes that reduce subsurface tar balls to highly divided oil forms while also allowing appreciable weathering despite burial. These findings prompted reassessment of current spill evaluation strategies. A protocol is proposed that combines the modeling of beach morphodynamics, an environmentally friendly coring survey, and well-calibrated hydrocarbon analysis.

Shallow sublittoral meiofauna communities and sediment polycyclic aromatic hydrocarbons (PAHs) content on the Galician coast (NW Spain), six months after the Prestige oil spill

The aim of this work was to detect the impact of Prestige oil spill on meiobenthic community structure at higher levels of taxonomic aggregation. In addition, the relationship between sediment individual polycyclic aromatic hydrocarbon (PAH) concentration and meiofauna community structure was investigated. Six months after the Prestige oil spill, meiobenthos community and sediment PAHs content from seven shallow subtidal localities along the Galician coast were studied. Two sites presented differences in community structure, characterized by high densities of nematodes, gastrotrichs and turbellarians, and low densities of copepods. Chrysene and triphenylene were only found at these two disturbed sites and could be responsible for differences of meiobenthos community structure. However, differences in community structure of sites could be linked with sedimentary parameters, and discrimination between the effect of PAHs and sedimentary parameters was impossible due to the lack of baseline studies on meiobenthos and PAHs contents in this area.

Characterization of sea surface chemical contamination after shipping accidents

A contamination survey was conducted after the beaching of the stricken cargo ship MSC Napoli in Lyme Bay on the south coast of Devon (UK). A grid of 22 coastal and offshore stations was sampled to investigate the extent of spilled oil and to screen for chemical contamination, as well as to evaluate the behavior of the oil at the air-sea interface. Samples were collected from the sea surface microlayer (SML) and from subsurface waters (SSW) at each station. The fuel oil spilled (IFO 380) was also analyzed. The determination of oil-related hydrocarbons (aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), terpanes, and steranes) and the screening for other harmful chemicals on the inventory of the MSC Napoli in the seawater samples, was performed by PTV-GC/ MS using large volume injection (LVI) techniques. Screening did not reveal the presence of any harmful chemicals other than petroleum-related compounds. Results afforded investigation of oil sources and spatial distributions of total PAH concentrations and enrichments in the sea surface microlayer (SML). Rather than a single source, oil fingerprinting analyses of the samples revealed a mixture of three types of oil: heavy fuel oil, lubricating oil, and a lighter oil (probably diesel oil). Enrichment factors (EF) in the SML (EF = C(SML)/C(SSW)) were calculated and, in the vicinity of the ship, approached 2000, declining with distance away from the wreck. These factors represent approximately a 1000-fold enrichment over typical coastal total PAH enrichments in the SML and reflected a clear petrogenic origin of the contamination (as demonstrated, for example, by a Fl/Pgamma ratio < 1). In addition, the spatial transport and fate (i.e., air-sea exchange processes and water column diffusion) of the oil-related hydrocarbons in the sea surface were investigated. Essentially, near the wreck, the SML was highly enriched in oil forming a visible sheen, both disrupting the normal air-seawater exchange processes and generating a downward diffusion flux of contaminants from the SML to the SSW. This was reflected by a higher occurrence of naphthalene relative to alkyl-naphthalenes in the SSW compared to the SML. The higher concentrations and different sources of oil found in the SML in comparison to those found in the SSW indicate that, if only subsurface water samples are investigated in isolation, the true extent and impact of a spill could be underestimated. It is important to simultaneously evaluate contamination in the sea surface during emergency response.

Effects of acute exposure to heavy fuel oil from the Prestige spill on a seabird

Large quantities of petroleum products are released into the marine environment as result of tanker wrecks. Such catastrophic events have a dramatic impact on marine ecosystems, affecting a broad range of species. Seabirds are placed at the uppermost trophic level of the marine food chain. Therefore, important toxic effects are expected in these organisms. The recent Prestige oil spill gave the opportunity to test this. A previous study reported that yellow-legged gulls (Larus michahellis) breeding in the oiled area (17 months after the spill) showed differences both in plasma biochemistry and in the total circulating levels of polycyclic aromatic hydrocarbons (TPAHs) in blood regard to gulls sampled in clean areas. In the present study, wild yellow-legged gulls were fed with heavy fuel oil from the Prestige oil spill (P-gulls) and compared with control gulls (C-gulls) fed only with the vehicle (vegetable oil). Consistent with the cited previous findings, gulls fed with fuel oil showed reduced glucose and inorganic phosphorus levels in plasma, as well as a trend to significantly reduced creatinine values. In addition, glucose concentration was negatively related to TPAH levels. Males but not females fed with fuel oil showed higher plasma activity of asparatate aminotransferase (AST) than controls. With regard to plasma activity of gamma-glutamyl transferase (GGT), the results were opposite to the previous study. The GGT activity increased in C-females, apparently to meet with increased liver metabolism due to egg laying demands, but not in P-females. Differences to the previous study possibly reflect different adaptive responses of these enzymes to an acute short-term exposure to heavy fuel oil. Since the yellow-legged gull belongs to a complex of species widely distributed throughout the Northern hemisphere, the results as a whole might provide a tool for future evaluations of short- and long-term effects of oil spills on seabirds. Decreased glucose and inorganic phosphorus levels in plasma are expected in both short- and long-lasting exposures to fuel oil, whereas responses of AST and GGT enzymes would depend on both the sex of individuals and the temporal pattern of exposure.