Oil Spill Environmental Forensics: the

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Oil Spill Environmental Forensics: the Hebei Spirit Oil Spill Case Un Hyuk Yim,† Moonkoo Kim,† Sung Yong Ha,† Sunghwan Kim,‡ and Won Joon Shim†,* †

Oil and POPs Research Group, South Sea Branch, KORDI, Geoje, Republic of Korea Department of Chemistry, Kyungpook National University, Daegu, Republic of Korea

‡

Based on the Marine Environmental Management Act in ROK, the responsible party should immediately commence natural resource damage assessment (NRDA) through the predesignated ad hoc institutes by Korean government when the volume of spilled oil is over 100 kL. Korea Ocean Research and Development Institute (KORDI), National Fisheries Research and Development Institute and National Park Service were mainly involved in NRDA with KORDI as the leading agency. Duplication in some aspects of NRDA (e.g., monitoring of oil contamination and ecosystem), however, could not be avoided at the initial stage and then it was appropriately coordinated in the long term monitoring stages. Oil contamination, toxic effects on organisms and ecosystem injury were the three main fields in the HSOS NRDA. Intensive spatiotemporal monitoring of oil contamination in the multimedia (e.g., water, sediment, pore-water, and biota) timely provided more quantitative and persuasive information than visual inspection of oil, which facilitated decision making in response operation as well as mitigation of debates among the stakeholders. Most heavily impacted areas by the HSOS incident include the Taean National Seashore Park with 32 recreational beaches. In addition to visual observation like shoreline cleanup assessment technique (SCAT), a rapid assessment and quantification of shoreline contamination was necessary to prioritize secondary cleanup operations and to make decisions for recreational beach reopening. To support this rapid assessment, a modified fluorometric on-site analysis of pore water was applied to the affected area. As an essential part of NRDA, long-term monitoring of residual petroleum hydrocarbons in multimedia environments was established. One of key components in oil spill environmental forensics is chemical fingerprinting, that is, the generation and comparison of diagnostic chemical features between oil samples and potentially impacted samples. Oil fingerprinting plays an important role in providing legal evidence to show the linkage between the spilled oil and the exposure of the target environments,3 which supports to determine the level of compensation for both the economic loss and environmental damage caused by the oil spill. In particular, varying volumes of three different Middle East crude oils spilled from the tanker in the HSOS case, which implies that there were three different source oils with various factorial mixing ratios in the environments. After oil enters into marine environments, two main factors, that is, mixing with background hydrocarbons and oil weathering, affect its hydrocarbon composition. Similar to other oil spill incidents, there was a lack of background contamination data for the spill sites. Furthermore, the alteration of the chemical composition of the spilled oils by weathering and chemical dispersion was largely unknown.

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HEBEI SPIRIT OIL SPILL (HSOS) INCIDENT IN REPUBLIC OF KOREA On the seventh of December 2007, the Hong Kong registered tanker M/V Hebei Spirit (146 848 GT), laden with 209 000 tonnes of crude oil, was struck by the crane barge Samsung No. 1 while anchored approximately five miles off Taean, on the west coast of the Republic of Korea (ROK). Approximately 10 900 tonnes of crude oil spilled into the sea from the Hebei Spirit. The collision resulted in punctures on tanks No. 1, 3, and 5 of the oil tanker, and three different types of crudes were spilled, namely Kuwait export crude (KEC), Iranian heavy crude (IHC), and UAE Upper Zakum crude (UZC). The spilled oil polluted more than 375 km of coastline to varying degrees.1,2 The HSOS incident was the recent largest marine oil spill in the world prior to the Deepwater Horizon oil spill in the Gulf of Mexico in April 2010. Emergency response operations for removal of bulk oil had been conducted until 2 January, 2008 and subsequent secondary response had continued until 10 October 2008. Total 4175 kL of liquid oils (not fully separated from water) and 32 074 tons of oiled solid waste including the disposable response equipment were recovered. When water contents of the recovered liquid oils was estimated as 50% by volume and percentage of oil in the recovered solid waste was assumed as 1% by weight, the total recovered oil was roughly calculated as 20% of the spilled oil. More than 1.3 million volunteers from all over ROK helped shoreline cleanup operations. The fast response at sea and on the shoreline and the help from a large number of volunteers resulted in the rapid removal of the spilled oil from the environment. Nonetheless, lingering oils have been found along the heavily impacted shorelines. © 2012 American Chemical Society

Published: May 14, 2012 6431

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Figure 1. Spatial distributions of petroleum hydrocarbon concentrations in pore water measured using an on-site fluorometric pore water analysis method by Kim et al. (2010). Spatial distributions on Feb. 21, 2008 (A) and on Jan. 29, 2009 (B).

To unravel these relationships, conventional tiered fingerprint approach including gas chromatography (GC) and mass spectrometry (MS) was applied to analyze fingerprint characteristics of spilled oil. Additionally, emerging fingerprinting techniques were also employed for further detail analysis. In this article, we aim to share the lessons learned from the HSOS case with respect to oil spill environmental forensic issues. In addition, future research and development needs are suggested to resolve the issues that were not scientifically addressed well in the HSOS case. Rapid Screening of Shoreline ContaminationFluorometric on-Site Analysis of Pore Water. Various assessment techniques have been applied at oil spill sites to evaluate oil contamination at impacted shorelines. TPH or PAH concentrations in sediments can be good proxies to detect oil contamination at the impacted shoreline. However, when using TPH or PAH concentrations in sediments, oil contamination levels and extent could not be clearly characterized because the quantification of chemicals in the sediments depends on the grain size and weight of the sediments themselves, which is especially true with coarse sediments. As an alternative, we found that oil contamination at a sandy shoreline can be better assessed by measuring oil concentrations in pore water rather than by measuring oil contents in sediments.4 Pore water can reflect sediment contamination, and the quantification of oil in pore water is not dependent on the grain size. Pore water can be analyzed using conventional GC methods for oil quantification. However, this analytical method is often impractical as a rapid screening tool at oil spill sites, considering the analysis time, cost, and the number of samples to be processed.5 Instead, the on-site fluorometric detection method was introduced to measure the oil concentration in pore water in a timely manner.4 Because crude oil includes aromatic fraction which is very sensitive to fluorometric analysis, we can get estimation of total petroleum hydrocarbon concentration in a sample using the fluorometric detection method

(method detection limit: 0.13 μg/L). Although the fluorometric technique may not be used to directly relate to GC measurement of oil content because the relative proportion of aromatics changes as oil degrades,6 it is capable of generating data comparable to those from GC but more rapidly and cost effectively than conventional GC technique.4,6,7 To compensate any deviation of fluorometric TPH measurement, GC analysis was also applied. In this study, the contamination level and temporal variation of dissolved/dispersed oil in pore water were monitored on-site using a portable fluorometer on monthly basis, and the results were illustrated using GIS mapping. Figure 1 shows results of the on-site beach monitoring on 76 days and ∼1 year after the spill. Approximately 50 samples or locations could be examined within a couple of hours. The results clearly showed the spatial and temporal variations of oil contamination at the beach. Currently, most of the beaches in the study area show local variations that approach the prespill contamination levels. However, continuous elevations in the oil concentration were also observed at certain local sites until January 2011. Long-Term Monitoring of Residual Oils in Multimedia. When oil enters into the marine environments it spreads and partitions into several compartments of aquatic systems, namely seawater, sediment, and biota. Even after visible oils were removed by a cleanup process, residual oils persisted in the multimedia environments. The objectives of long-term monitoring of multimedia were to assess the area-wide extent of oil contamination and to identify the persistency of residual oiling. Sampling area and frequencies were adjusted according to the oiling status. Most of field works were focused on the heavily contaminated sites of Taean County, and offshore remote islands were also visited.8 Four days after the HSOS, researchers were dispatched to the scene and collected ephemeral data. Since then, seawater, sediment, and biota samples were collected weekly, monthly, and seasonally from intertidal, subtidal, and offshore regions. Heavily contaminated intertidal regions in Taean were investigated more 6432

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biomarker compounds including hopanes and steranes were very useful for source identification. However, the challenge in oil fingerprinting for this spill was the continuous mixing, to varying degrees, of the three crude oils during the spill. The puncture sizes of each hole were different, and thus, their mixing rate varied according to time. Ratios using the regular C27-, C28-, C29-homologous sterane series (cholestane, ergostane, and stigmastane) provided source allocation information. In the double ratio plot using sterane homologue series, spilled oils were located in the mixing line between IHC and KEC, implying that mixing could be explained using specific biomarker compounds. Further studies are required to develop multicomponent mixing model or chemical mass balance model for quantitative source allocation of spilled oil.10 Background Contamination. The debate continues among the concerned parties regarding the contribution of background hydrocarbon contamination to the spilled oil. For instance, the Exxon Valdez oil spill evoked controversy for the sources of background hydrocarbons and their relative contribution to the spilled source, Alaska North Slope crude oil. Natural seeping, coal, shale, and anthropogenic activities were discussed as sources of background hydrocarbons.11,12 Natural seeping is one of the most masking backgrounds when the reservoir of spilled oil was near the seeping region.13 In ROK, the high population density and industrial activities along the coast have resulted in elevated levels of anthropogenic hydrocarbon backgrounds.14 Together with land-based pollution, heavy navigational activities also contribute to the elevation in the hydrocarbon background level. Despite the decreasing trend of middle- to large-scale oil spill accidents (>50 kL), the average number of spills and total amount of oil spilled in ROK over the past nineteen years (1990−2008) were 354 and 3406 kL, respectively.1 Small-scale spill accidents occur almost daily in ROK, which leave traces that complicate the fingerprints of spilled oil. Even during the period of cleanup operations for the HSOS, small-scale spills occurred off the west coast of ROK and mixed with the HSOS residual oils. These unidentified oils fostered debate about the possible resuspension of submerged oil. Tiered fingerprinting approaches were applied to give defensible and persuasive evidence for source identification. Most of the newly stranded oils at the beach were found to be unmatched with HSOS oil; illegal disposal or unintentional spills were proposed as the main causes. Weathering and Its Effects on Oil Fingerprints. In the marine environment, the spilled oil is immediately subject to a variety of weathering processes, including evaporation, dissolution, emulsification, microbial degradation, photooxidation, adsorption to suspended matter, and deposition on the sea floor. These processes determine its ultimate fate and impact on the environment.13 Evaporation and dissolution are the primary processes that affect the chemical composition/fingerprint of spilled oil in the hours or days following an oil spill. The effects of evaporative weathering on the chemical composition of the oil are generally predictable and depend on the original composition of the spilled oil.15 The dissolution process is important in recognizing the impact of spilled oil on marine biota. The effects of biodegradation on a spilled oil’s chemical fingerprint are not obvious in the short term. Parent PAHs often are biodegraded more rapidly than their alkyl homologues.16 The exposure of spilled oil to solar radiation leads to several free radical photooxygenation reactions that produce a variety of oxygen-containing compounds.17 Photooxidation and biodegradation are the only two natural

intensively than other impacted areas. Remote areas were also visited periodically. Total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAHs) including 16 U.S. Environmental Protection Agency PAHs, alkylated PAHs, and biomarker compounds were analyzed. Immediately after the spill, the PAH concentration in the intertidal seawater was as high as 5170 ng/L. The maximum concentration of TPH, 16 PAHs and alkylated PAHs in intertidal sediments reached 1630 μg/g, 3350 ng/g and 66 430 ng/g (dry weight basis), respectively. The concentration of alkylated PAHs in oysters collected from the Taean were approximately 40−500 times higher than that of the background level for oysters (200 ng/g or less). Long-term monitoring results show that the concentration of petroleum hydrocarbons in multimedia decreased rapidly for the first six month. The PAH concentrations in the seawater decreased drastically, to as low as 100 ng/L, one month after the spill, and then decreased steadily and fluctuated within the range of background concentrations. One year after the spill, the average concentration of TPH, 16 PAHs and alkylated PAHs in intertidal sediments decreased by as much as 7, 10, and 20 times, respectively, compared with the initial concentration level. The overall PAH concentrations in oysters decreased exponentially over time, and most of the sites showed seasonal variations approaching the prespill contamination level. However, oysters at mud flat, boulder-armored beaches showed relatively higher PAH concentrations year-round. In particular, oysters from a boulder-armored beach, Garumi, showed elevated PAH concentrations of 22 400 ng/g in September 2009. Varying Degree Mixture of Three Source Oils. Every year, ROK imports more than 870 million barrels of crude oil from various oil producers, and it is ranked as the seventh world consumer of crude oil. According to recent three year statistics (2006−2008), more than 80% of crude oil imported to ROK came from the Middle East.9 Among the Middle Eastern countries, Saudi Arabia is the largest oil exporter, followed by the United Arab Emirates (UAE), Kuwait, Iran, Qatar and Oman. These statistics are well reflected in the cargo oils of the M/V Hebei Spirit; four different types of Middle Eastern crude oil, including KEC, IHC, UZC, and Saudi Arabia Khafj, were loaded, and three of them were spilled. The proportional spill volumes of the three cargo oils were estimated to 43.4%, 42.8%, and 13.8% for KEC, IHC, and UZC, respectively. Their physical properties, such as density, viscosity and pour point, were similar each other. However, their asphalthene and resin contents, which were known to affect the formation of emulsions, showed significant differences among them. Our laboratory experiments revealed that IHC and KEC produced stable water-in-oil emulsions, while UZC resulted in a meso-stable emulsion. Due to high wind and rough sea conditions during the incident, a water-in-oil emulsion was formed right after the spill, and most of the intertidal area was affected by this high-water-content visco-elastic oil. Simulation results of their environmental fates using an oil weathering model show that the major weathering process was evaporation, followed by dispersion. Four days after the spill, 22−30% of the spilled oil had evaporated, and 0.7−10% had dispersed, depending on the oil type.10 These three cargo oils showed similar but distinguishable hydrocarbon fingerprints. For example, their normal alkane distribution showed a similar pattern, but the diagnostic ratio of pristane to phytane was source specific and was a good source indicator. Likewise, double ratios using alkylated PAHs and 6433

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Figure 2. (A) High-resolution mass spectrum and expanded mass spectrum of weathered oil spilled from the HSOS. (B) Class distribution of the oil sample and (C) the carbon number vs DBE plot of S1 class compounds.

of C28-18α(H)-22,29,30-trisnorneohopane to C28-17α(H)22,29,30-trisnorhopane (Ts/Tm), and C29-17α(H), 21β(H)30-norhopane to C30-17α(H), 22β(H)-hopane provided distinctive source identification power. Similarly, sterane biomarker ratios using C27-, C28-, C29-homologous sterane series were also very informative for differentiating sources. Mixtures of IHC and KEC were identified as major spill sources regardless of masking effects of biodegradation. However, in this study, photooxidation does not appear to be a major weathering process.10 Emerging Oil Fingerprinting Techniques Used in This Study. When there exists complication in oil fingerprinting like the HSOS case, more distinctive oil fingerprinting tools are required. The stable isotope compositions of the individual compounds in weathered oil are known to remain relatively stable compared with the molecular compositions and thus can be used effectively as a correlation parameter.18−20 Stable isotopic techniques are useful to analyze oil residues that have undergone extensive degradation, to distinguish refined products that may be very similar chromatographically, or to study light oils that lack conventional marker compounds, such as steranes and terpanes.21−23 For instance, the isotopic technique has been used to trace the source of stranded oil from several oil spill cases, including the Exxon Valdez,24 the Erika,25 and others.26 In this study, stranded oils were analyzed by gas chromatography/isotope ratio mass spectrometry (GC/IRMS) to determine the stable carbon isotope ratios of n-alkanes. Their isotopic compositions were compared with those of possible source oils. The preliminary results showed that stranded oils collected in three months after

processes that destroy petroleum hydrocarbons and remove them from the environment. For the scale of the weathering degree of stranded oil, four level categorization was used in the HSOS case: initial, moderate, advanced, and extreme stages.10 Weathering characteristics and their progression were determined from the pattern changes in the distributions of saturated hydrocarbon (SHC), PAH target analytes, and their weathering ratios. Weathering percentages of residual oil were determined using C30-17α(H), 22β(H)-hopane as the internal conservative reference. Among various weathering processes, evaporation was found to be the most dominant process during the initial stage of the spill. In the HSOS case, oils classified as the initial weathering stage lost 28.9% of the original spilled oil. Moderate weathering stage oils showed the effects of both evaporation and dissolution, losing an additional 8.8% from the initially weathered oil. Oils belonging to these stages were stranded oils collected within 3 months after the spill. Advanced and extreme weathering stage samples exhibited the time-lagged effects of biodegradation, resulting up to total loss of 60.3% combined with other weathering processes. Each weathering process has been monitored using compound profiles and weathering indices. Among them, biodegradation had the most significant effect on the fingerprints of stranded oils. Even well-established double ratios of alkylated phenanthrenes and dibenzothiophenes were slightly changed, which complicated the source identification. Only ratios using biomarkers provided defensible source identification fingerprints in the later weathering stage oils. Among hopanes, ratios 6434

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Figure 3. An integrative area-wide survey for submerged oil was conducted at potential oil accumulation areas. (A) Line survey map and results of the V-SORS survey. (B) The V-SORS was towed to identify and recover oil. Oiling was estimated by oil spots in snares (inset photo). (C) A dredge net was towed to artificially suspend potential submerged oil.

compounds had potential to be used as conservative fingerprints in the HSOS case. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is one of the most powerful techniques that can be used to study oils at the molecular level.32,33 As weathering proceeds, crude oils that are subjected to microbial or photooxidation processes can generate a significant amount of polar molecules. The increased number of polar compounds can contribute to UCM, which are often found in degraded crude oil samples. When FT-ICR MS is coupled with electrospray or atmospheric pressure photo ionization, it can be effectively used to study polar and heavy components of crude oils.34−38 Stranded oil samples with varying degrees of weathering were analyzed to see the detailed compositional changes using FT-ICR MS. Significant increase of polar compounds like N-, S-, O-containing heterocyclic aromatics were found in the resin fraction of the weathered oil. High-resolution mass spectrum of an oil sample contained over 20 peaks within a ∼ 0.4 m/z window, which could be converted into elemental formulas using data interpretation like double bond equivalence (DBE) (Figure 2). The elemental composition and structural information obtained by FT-ICR MS are expected to be further used to develop new fingerprinting tools. Submerged Oil: Fate of Dispersed or Wash-out Oil. One of the misinformed environmental fates of oil relayed to

the spill retained the stable carbon isotopic compositions of the cargo oils distinguishable from ambient contaminations. While compositional signatures has altered significantly due to weathering processes, stable isotope ratios of alkanes remained relatively unaltered and thus they can be used effectively, in conjunction with conventional molecular makers, to trace HSOS or to allocate pollution sources among the three oils spilled. Comprehensive two-dimensional gas chromatography (GCxGC) has the potential to revolutionize forensic oil spill analysis. GC×GC is capable of separating an order of magnitude more compounds from complex mixtures than traditional GC.27 The increased chromatographic resolution is achieved by using two chromatographic columns with different selectivities coupled together by a modulator. Also, the GC×GC detectors need to have a fast response. Flame ionization detectors are widely used, and fast time-of-flight mass spectrometers (TOF MS) are well-suited for GC×GC.28 GC×GC facilitates the understanding of the sources, weathering, and toxicity of unresolved complex mixtures (UCM) hydrocarbons.27,29−31 In the HSOS case, GC×GC was promising to comprehensively evaluate the varying degree of mixing effects of the three spill sources and the abiotic and/or biotic effects of weathering. GC×GC facilitated the initial screening of various types of hydrocarbons using group type analysis and the application of isoprenoid compounds like biphytane and methyl hopanoids with the help of enhanced separation. We found these 6435

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the public during the HSOS was sunken or submerged oil. General public raised concerns about the effects of these oils on the benthic ecosystem. Video taken near the surf zone and oilcontaminated anchor and fishing gear were presented as evidence for the submerged oil. The specific gravities of the cargo oils in M/V Hebei Spirit were in the range of 0.85−0.87; theoretically, fresh spilled oil does not sink. However, when oil is stranded on sand beaches or mixed with sand in the surf zone, spilled oil can be settled down. In a strict sense, these phenomena could be classified as wash-out oil from the intertidal zone after aggregated with sand.39 Another ambiguous fate of oil is mechanically and/or chemically dispersed oil. When oil enters seawater, wave energy, with or without oil spill dispersant (OSD), disperses oil into the water column. OSD significantly enhances water column concentrations of petroleum hydrocarbons. During the cleanup of the HSOS, approximately 300 kL of OSD was used.1 One common misconception was that OSD enhanced the formation of negative buoyancy oil droplets, so-called “oil-balls” introduced by Korean mass media. Furthermore, bottom sediments and benthic bivalves such as ark-shell and pen shell in the oil spill area showed elevated levels of petroleum hydrocarbons, especially alkylated PAHs. This contamination was possibly due to dispersed oil reaching the bottom of the seafloor. Wash-out oil and the misconceived oil-balls were widely accepted as evidence of the area-wide existence of submerged oil. There are many techniques and tools for tracking subsurface oil, which determine the location of oil both in the water column and on the seabed. These techniques include visual observations, geophysical and acoustic methods, remote sensing, water-column and seabed sampling, in situ detectors, and trawl net sampling. The most direct and simplest methods, such as diver observations and direct sampling, are widely used, but they are labor intensive and slow. More advanced approaches, such as remote sensing and acoustic techniques, are also prone to misuse and produce ambiguous data that are subject to misinterpretation.39,40 When designing a submerged oil survey, a combination of those approaches is needed to overcome the shortcomings of each approach and to provide a comprehensive view on the contamination. To clarify the dispute regarding submerged oil in the HSOS case, two different approaches were applied. First, site-specific direct visual surveys using grab sampling, diver observation, and the pumping out of sediment to sea surface were conducted at most of the suspected areas. Some surf zone and subtidal regions near the heavily oiled intertidal zone exhibited signs of oil sand aggregates, indicating that wash-out oil from the intertidal zone affected subtidal region. Another approach was an area-wide survey using the vessel-submerged oil recovery system (V-SORS) and a dredge net. Various stakeholders, including several government agencies, fishermen associations, and compensation surveyors, joined the comprehensive submerged oil surveys in May 2009. The V-SORS consisted of a steel pipe, chains and snares around the chains. The system was towed behind a vessel, and dragged along the bottom. The oil coverage on the snares and the buoyant oil on the dredge net were roughly estimated. Four V-SORS and two dredge nets were used to identify areas of submerged oil and to recover oil in potential accumulation areas. The amount of oil recovered was very low, mostly in the form of oil droplets, suggesting that there was little or no massive submerged oil pool, but only small amounts of oil droplets associated with bottom sediments (Figure 3).

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AUTHOR INFORMATION

Corresponding Author

*Phone: +82-55-639-8671; fax: +82-55-639-8689; e-mail: [email protected]. Notes

The authors declare no competing financial interest. Biography Un Hyuk Yim is a Principal Research Scientist at Korea Ocean Research and Development Institute (KORDI). He has over 15 years’ experience studying the oil pollution in Korea and worked extensively on the Hebei Spirit oil spill (HSOS) since 2007. Moonkoo Kim is a Senior Research Scientist at KORDI where he carries out researches on stable isotope analysis as well as rapid assessment of oil pollution. Sung Yong Ha is a Research Specialist at KORDI. He has been extensively studying the environmental fate of the HSOS oil. Sunghwan Kim is Assistant Professor of Chemistry at the Kyungpook National University. He has published over 40 peer reviewed papers on application of high resolution mass spectrometry to understand complex organic mixture such as humic substance and crude oil. Won Joon Shim is the head of Oil and POPs Research Group at KORDI. He is a principal investigator of the environmental impact assessment of the HSOS. He has been the author of over 100 peer reviewed papers on the environmental occurrence and fate of oil and POPs.

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ACKNOWLEDGMENTS This work was supported by project no. PM56951 (grants-in-aid from the Ministry of Land, Transport and Maritime Affairs, ROK). We appreciate the valuable suggestions on the manuscript by Dr. Y.H. Kim and kind copyright transfer of the valuable photos taken by Jungdoilbo.

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REFERENCES

(1) KCG. Korea Coast Guard 2008 White Paper 2008, 516. (2) ITOPF. The environmental impact of the Hebei Spirit oil spill, Taean South Korea (7th December 2007) 2008. (3) Stout, S. A.; Wang, Z., Chemical fingerprinting of spilled or discharged petroleum - methods and factors affecting petroleum fingrerprints in the environment. In Oil Spill Environmental Forensics: Fingerprinting and Source Identification; Wang, Z., Stout, S. A., Eds.; Academic Press: Burlington, MA, 2007; pp 1−45. (4) Kim, M.; Yim, U. H.; Hong, S. H.; Jung, J. H.; Choi, H. W.; An, J.; Won, J.; Shim, W. J. Hebei Spirit oil spill monitored on site by fluorometric detection of residual oil in coastal waters off Taean, Korea. Mar. Pollut. Bull. 2010, 60 (3), 383−9. (5) Christensen, J. H.; Tomasi, G. Practical aspects of chemometrics for oil spill fingerprinting. J. Chromatogr., A 2007, 1169 (1−2), 1−22. (6) Lambert, P. A literature review of portable fluorescence-based oilin-water monitors. J. Hazard. Mater. 2003, 102 (1), 39−55. (7) Lambert, P. Field fluorometers as dispersed oil-in-water monitors. J. Hazard. Mater. 2003, 102 (1), 57−79. (8) MLTM 2010. Environmental Impact Assessment of the Hebei Spirit Oil Spill; Ministry of Land, Transport and Maritime Affairs: Republic of Korea, 2011; p 999. (9) KNOC Statistics of oil supply and demand in Korea. http:// www.petronet.co.kr/main2.jsp (accessed October 20, 2011), (10) Yim, U. H.; Ha, S. Y.; An, J. G.; Won, J. H.; Han, G. M.; Hong, S. H.; Kim, M.; Jung, J. H.; Shim, W. J. Fingerprint and weathering characteristics of stranded oils after the Hebei Spirit oil spill. J. Hazard. Mater. 2011, 197, 60−69.

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Feature

dimensional gas chromatography. Environ. Forensics 2006, 7 (1), 33− 44. (30) Ventura, G. T.; Kenig, F.; Reddy, C. M.; Frysinger, G. S.; Nelson, R. K.; Van Mooy, B.; Gaines, R. B. Analysis of unresolved complex mixtures of hydrocarbons extracted from Late Archean sediments by comprehensive two-dimensional gas chromatography (GC×GC). Org. Geochem. 2008, 39 (7), 846−867. (31) Booth, A. M.; Sutton, P. A.; Lewis, C. A.; Lewis, A. C.; Scarlett, A.; Chau, W.; Widdows, J.; Rowland, S. J. Unresolved complex mixtures of aromatic hydrocarbons: Thousands of overlooked persistent, bioaccumulative, and toxic contaminants in mussels. Environ. Sci. Technol. 2007, 41 (2), 457−464. (32) Marshall, A. G.; Rodgers, R. P. Petroleomics: The next grand challenge for chemical analysis. Acc. Chem. Res. 2004, 37 (1), 53−59. (33) Hsu, C. S.; Hendrickson, C. L.; Rodgers, R. P.; McKenna, A. M.; Marshall, A. G. Petroleomics: Advanced molecular probe for petroleum heavy ends. J. Mass Spectrom. 2011, 46 (4), 337−343. (34) Hughey, C. A.; Rodgers, R. P.; Marshall, A. G.; Qian, K. N.; Robbins, W. K. Identification of acidic NSO compounds in crude oils of different geochemical origins by negative ion electrospray Fourier transform ion cyclotron resonance mass spectrometry. Org. Geochem. 2002, 33 (7), 743−759. (35) Hughey, C. A.; Rodgers, R. P.; Marshall, A. G.; Walters, C. C.; Qian, K. N.; Mankiewicz, P. Acidic and neutral polar NSO compounds in Smackover oils of different thermal maturity revealed by electrospray high field Fourier transform ion cyclotron resonance mass spectrometry. Org. Geochem. 2004, 35 (7), 863−880. (36) Hur, M.; Yeo, I.; Kim, E.; No, M. H.; Koh, J.; Cho, Y. J.; Lee, J. W.; Kim, S. Correlation of FT-ICR mass spectra with the chemical and physical properties of associated crude oils. Energy Fuel. 2010, 24, 5524−5532. (37) Cho, Y.; Kim, Y. H.; Kim, S. Planar limit-assisted structural interpretation of saturates/aromatics/resins/asphaltenes fractionated crude oil compounds observed by fourier transform ion cyclotron resonance mass spectrometry. Anal. Chem. 2011, 83 (15), 6068−6073. (38) Kim, S.; Rodgers, R. P.; Marshall, A. G. Truly ″exact″ mass: Elemental composition can be determined uniquely from molecular mass measurement at similar to 0.1 mDa accuracy for molecules up to similar to 500 Da. Int. J. Mass Spectrom. 2006, 251 (2−3), 260−265. (39) Committee on Marine Transportation of Heavy Oils, NRC. Spills of Nonfloating Oils: Risk and Response; National Academy Press: Washington, D.C., 1999; p 88. (40) Michel, J. Assessment and Recovery of Submerged Oil: Current State Analysis; U.S. Coast Guard: Groton, CT, 2006; p 3−33.

(11) Short, J. W.; Heintz, R. A. Identification of Exxon Valdez oil in sediments and tissues from Prince William Sound and the northwestern Gulf of Alaska based on a PAH weathering model. Environ. Sci. Technol. 1997, 31 (8), 2375−2384. (12) Boehm, P. D.; Page, D. S.; Burns, W. A.; Bence, A. E.; Mankiewicz, P. J.; Brown, J. S. Resolving the origin of the petrogenic hydrocarbon background in Prince William Sound, Alaska. Environ. Sci. Technol. 2001, 35 (3), 471−479. (13) NRC. Oil in the Sea III: Inputs, Fates, And Effects. National Research Council of the National Academies: The National Academies Press: Washington DC, 2003; p 265. (14) Yim, U.; Hong, S.; Shim, W. Distribution and characteristics of PAHs in sediments from the marine environment of Korea. Chemosphere 2007, 68 (1), 85−92. (15) Wang, Z. D.; Fingas, M.; Blenkinsopp, S.; Sergy, G.; Landriault, M.; Sigouin, L.; Foght, J.; Semple, K.; Westlake, D. W. S. Comparison of oil composition changes due to biodegradation and physical weathering in different oils. J. Chromatogr., A 1998, 809 (1−2), 89− 107. (16) Prince, R. C.; Owens, E. H.; Sergy, G. A. Weathering of an Arctic oil spill over 20 years: The BIOS experiment revisited. Mar. Pollut. Bull. 2002, 44 (11), 1236−1242. (17) Prince, R. The roles of photooxidation and biodegradation in long-term weathering of crude and heavy fuel oils. Spill Sci. Technol. Bull. 2003, 8 (2), 145−156. (18) Mazeas, L.; Budzinski, H.; Raymond, N. Absence of stable carbon isotope fractionation of saturated and polycyclic aromatic hydrocarbons during aerobic bacterial biodegradation. Org. Geochem. 2002, 33 (11), 1259−1272. (19) Sun, Y. G.; Chen, Z. Y.; Xu, S. P.; Cai, P. X. Stable carbon and hydrogen isotopic fractionation of individual n-alkanes accompanying biodegradation: Evidence from a group of progressively biodegraded oils. Org. Geochem. 2005, 36 (2), 225−238. (20) Li, Y.; Xiong, Y. Q.; Yang, W. Y.; Xie, Y. L.; Li, S. Y.; Sun, Y. G. Compound-specific stable carbon isotopic composition of petroleum hydrocarbons as a tool for tracing the source of oil spills. Mar. Pollut. Bull. 2009, 58 (1), 114−117. (21) Philp, R. P. The emergence of stable isotopes in environmental and forensic geochemistry studies: A review. Environ. Chem. Lett. 2007, 5 (2), 57−66. (22) Wang, Z. D.; Fingas, M. F. Development of oil hydrocarbon fingerprinting and identification techniques. Mar. Pollut. Bull. 2003, 47 (9−12), 423−452. (23) Jeffrey, A. W. A., Application of stable isotope ratios in spilled oil identification. In Oil Spill Environmental Forensics: Fingerprinting and Source Identification; Wang, Z., Stout, S. A., Eds.; Academic Press: NY, 2007; pp 207−227. (24) Bence, A. E.; Kvenvolden, K. A.; Kennicutt, M. C. Organic geochemistry applied to environmental assessments of Prince William Sound, Alaska, after the Exxon Valdez oil spillA review. Org. Geochem. 1996, 24 (1), 7−42. (25) Mazeas, L.; Budzinski, H. Molecular and stable carbon isotopic source identification of oil residues and oiled bird feathers sampled along the Atlantic coast of France after the Erika oil spill. Environ. Sci. Technol. 2002, 36 (2), 130−137. (26) Wang, Z. D.; Fingas, M.; Landriault, M.; Sigouin, L.; Castle, B.; Hostetter, D.; Zhang, D. C.; Spencer, B. Identification and linkage of tarballs from the coasts of Vancouver island and northern California using GC/MS and isotopic techniques. J. High Res. Chromatogr. 1998, 21 (7), 383−395. (27) Frysinger, G. S.; Gaines, R. B.; Xu, L.; Reddy, C. M. Resolving the unresolved complex mixture in petroleum-contaminated sediments. Environ. Sci. Technol. 2003, 37 (8), 1653−1662. (28) Dallüge, J. Comprehensive two-dimensional gas chromatography: A powerful and versatile analytical tool. J. Chromatogr., A 2003, 1000 (1−2), 69−108. (29) Nelson, R. K.; Kile, B. M.; Plata, D. L.; Sylva, S. P.; Xu, L.; Reddy, C. M.; Gaines, R. B.; Frysinger, G. S.; Reichenbach, S. E. Tracking the weathering of an oil spill with comprehensive two6437

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