Two years after the Hebei Spirit oil spill: residual crude-derived hydrocarbons and potential AhR-mediated activities in coastal sediments

The Hebei Spirit oil spill occurred in December 2007 approximately 10 km off the coast of Taean, South Korea, on the Yellow Sea. However, the exposure and potential effects remain largely unknown. A total of 50 surface and subsurface sediment samples were collected from 22 sampling locations at the spill site in order to determine the concentration, distribution, composition of residual crudes, and to evaluate the potential ecological risk after two years of oil exposure. Samples were extracted and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), 20 alkyl-PAHs, 15 aliphatic hydrocarbons, and total petroleum hydrocarbons using GC-MSD. AhR-mediated activity associated with organic sediment extracts was screened using the H4IIE-luc cell bioassay. The response of the benthic invertebrate community was assessed by mapping the macrobenthic fauna. Elevated concentrations of residual crudes from the oil spill were primarily found in muddy bottoms, particularly in subsurface layers. In general, the bioassay results were consistent with the chemistry data in a dose-dependent manner, although the mass-balance was incomplete. More weathered samples containing greater fractions of alkylated PAHs exhibited greater AhR activity, due to the occurrence of recalcitrant AhR agonists present in residual oils. The macrobenthic population distribution exhibits signs of species-specific tolerances and/or recolonization of certain species such as Batillaria during weathering periods. Although the Hebei Spirit oil spill was a severe oil exposure, it appears the site is recovering two years later.     

Genotoxicity and endocrine-disruption potentials of sediment near an oil spill site: two years after the Hebei Spirit oil spill

The Hebei Spirit oil spill episode (December 7, 2007) has affected the western coastal area of South Korea; however, there is limited information on the potential toxicity of the oil spill to the ecosystem or humans. The potential toxicity of sediments collected from the affected area (n = 22) 2 years after the spill was evaluated. Acute lethal toxicity tests using Vibrio fischeri and Moina macrocopa and tests for genotoxicity and alteration of steroidogenesis using chicken DT40 cells and H295R cells, respectively, were conducted. Both crude and weathered oil extracts were evaluated in order to link the observed toxicity in the sediment extracts to the oil spill. Whereas toxicity to bacteria and daphnids was observed in only two elutriate samples, 10 of the 22 sediment extracts showed genotoxic potential in DT40 cells. The mechanisms of genotoxicity involved nucleotide excision repair (XPA(-/)), homologous recombination (RAD54(-/-)), and translesion synthesis pathways (REV3(-/-)). In addition, nine sediment extracts caused significantly greater production of E2 in H295R cells, and significant up-regulation of CYP19, CYP11B2, and 3βHSD2 by sediment extracts was observed. The pattern of toxicities observed in both crude and weathered oil samples was similar to that observed in the sediment extracts. The genotoxicicity and endocrine-disruption potential of the sediment extracts suggest a need for long-term followup for such toxicity in humans and wildlife in this area.     

Isotopic constraints on the fate of petroleum residues sequestered in salt marsh sediments

To provide a new perspective on the fate of petroleum in the marine environment, we utilized variations in the natural abundance of radiocarbon (14C) to detect and quantify petroleum residues that have persisted in Wild Harbor sediments, West Falmouth, MA, for more than 30 years. The 5730-yr half-life of 14C makes this isotope ideal for the detection of fossil-fuel-derived contaminants (14C free) within different fractions of natural organic matter (modern 14C content) in environmental matrixes. Samples of both contaminated and uncontaminated sediments were sequentially treated, first by solvent extraction, followed by saponification, and then acid hydrolysis. Radiocarbon analysis of the sediment residues and select extracts was performed to probe for the presence of fossil fuel contaminants and/or their metabolites in different pools of sedimentary organic matter. Our results indicate that the majority of fossil carbon is solvent-extractable and has not been incorporated in the insoluble organic matter in sediment. Unextracted sediments contaminated with petroleum contain significantly less 14C than extracted sediments, and isotope mass balance calculations suggest that up to approximately 9% of the total organic carbon (TOC) in the petroleum contaminated sediment horizons is derived from solvent-extractable petroleum. These estimates are similar to values calculated when the total quantities of oil (measured by gas chromatography with flame ionization detector (GC-FID)) are compared to TOC content (determined by elemental analysis). These results pave the way for applications of this isotopic approach to more complex environmental systems where the fate of contaminants is less certain.     

Salt marsh recovery and oil spill remediation after in-situ burning: effects of water depth and burn duration

Effects of water depth, burn duration, and diesel fuel concentration on the relationship between recovery of marsh vegetation, soil temperature, and oil remediation during in-situ burning of oiled mesocosms were investigated. The water depth over the soil surface during in-situ burning was a major factor controlling recovery of the salt marsh grass, Spartina alterniflora. Ten centimeters of water overlying the soil surface was sufficient to protect the marsh soil from burn impacts with soil temperatures <37 degrees C and high plant survival rate. In contrast, a water table 10 cm below the soil surface resulted in mean soil temperatures > 100 degrees C at the 2-cm soil depth, which completely inhibited the post-burn recovery of S. alterniflora. Although poor plant recovery was also apparent in the treatments with 0 and 2 cm of water over the soil surface, this result was likely due to the chemical stress of the diesel fuel used to create the fire rather than the heat, per se, which never reached the estimated lethal temperature of 60 degrees C. In-situ burning effectively removed more than 95% of floating oil from the water surface. Thus, in-situ burning prevented the oil from potentially contaminating adjacent habitats. However, in-situ burning did not effectively remediate the oil that had penetrated the soil.     

Estimate of oil persisting on the beaches of Prince William Sound 12 years after the Exxon Valdez oil spill

We estimated the amount of oil remaining in Prince William Sound, Alaska, 12 yr after the 1989 Exxon Valdez spill to assess its importance as a long-term reservoir of toxic hydrocarbons. We found oil on 78 of 91 beaches randomly selected according to their oiling history. Surface oiling was recorded for randomly placed quadrats, which were then excavated and examined for subsurface oil. The cumulative area of beach contaminated by surface or subsurface oil was estimated at 11.3 ha. Surface oil varied little with tide height, but subsurface oil was more prevalent at the middle tide heights. The mass of remaining subsurface oil is conservatively estimated at 55 600 kg. Analysis of terpanes indicated that over 90% of the surface oil and all of the subsurface oil was from the Exxon Valdez and that Monterey Formation oil deposited after the 1964 Alaska earthquake accounted for the remaining surface oil. These results indicate that oil from the Exxon Valdez remains by far the largest reservoir of biologically available polycyclic aromatic hydrocarbons on beaches impacted by the spill and that biota dependent on these beaches risk continued exposure.     

Slightly weathered Exxon Valdez oil persists in Gulf of Alaska beach sediments after 16 years

Oil stranded by the 1989 Exxon Valdez spill has persisted in subsurface sediments of exposed shores for 16 years. With annualized loss rates declining from approximately 68% yr(-1) prior to 1992 to approximately 4% yr(-1) after 2001, weathering processes are retarded in both sediments and residual emulsified oil ("oil mousse"), and retention of toxic polycyclic aromatic hydrocarbons is prolonged. The n-alkanes, typically very readily oxidized by microbes, instead remain abundant in many stranded emulsified oil samplesfrom the Gulf of Alaska. They are less abundant in Prince William Sound samples, where stranded oil was less viscous. Our results indicate that, at some locations, remaining subsurface oil may persist for decades with little change.     

Level and degradation of Deepwater Horizon spilled oil in coastal marsh sediments and pore-water

This research investigates the level and degradation of oil at ten selected Gulf saltmarsh sites months after the 2010 BP Macondo-1 well oil spill. Very high levels (10-28%) of organic carbon within the heavily oiled sediments are clearly distinguished from those in pristine sediments (<3%). Dissolved organic carbon in contaminated pore-waters, ranging up to hundreds of mg/kg, are 1 to 2 orders of magnitude higher than those at pristine sites. Heavily oiled sediments are characterized by very high sulfide concentrations (up to 80 mg/kg) and abundance of sulfate reducing bacteria. Geochemical biomarkers and stable carbon isotope analyses fingerprint the presence of oils in sediments. Ratios of selected parameters calculated from the gas chromatograph spectra are in a remarkable narrow range among spilled oils and initial BP crude. At oiled sites dominated by C(4) plants, δ(13)C values of sediments (-20.8 ± 2.0‰) have been shifted significantly lower compared to marsh plants (-14.8 ± 0.6‰) due to the inflow of isotopically lighter oil (-27 ± 0.2‰). Our results show that (1) lighter compounds of oil are quickly degraded by microbes while the heavier fractions of oil still remain and (2) higher inputs of organic matter from the oil spill enhance the key microbial processes associated with sulfate reducing bacteria.     

Impact of the deepwater horizon oil spill on bioavailable polycyclic aromatic hydrocarbons in Gulf of Mexico coastal waters

An estimated 4.1 million barrels of oil and 2.1 million gallons of dispersants were released into the Gulf of Mexico during the Deepwater Horizon oil spill. There is a continued need for information about the impacts and long-term effects of the disaster on the Gulf of Mexico. The objectives of this study were to assess bioavailable polycyclic aromatic hydrocarbons (PAHs) in the coastal waters of four Gulf Coast states that were impacted by the spill. For over a year, beginning in May 2010, passive sampling devices were used to monitor the bioavailable concentration of PAHs. Prior to shoreline oiling, baseline data were obtained at all the study sites, allowing for direct before and after comparisons of PAH contamination. Significant increases in bioavailable PAHs were seen following the oil spill, however, preoiling levels were observed at all sites by March 2011. A return to elevated PAH concentrations, accompanied by a chemical fingerprint similar to that observed while the site was being impacted by the spill, was observed in Alabama in summer 2011. Chemical forensic modeling demonstrated that elevated PAH concentrations are associated with distinctive chemical profiles.     

葡萄酒产业30年发展回顾

本文从产量变化、葡萄品种与酒种区域化、规范与标准建设、技术工艺变迁、科研队伍建设等方面对改革开放30年来我国葡萄酒行业的发展与变化进行了较为详细的回顾,以期对未来葡萄酒产业的发展提供借鉴.     

In-situ burning of oil in coastal marshes. 2. Oil spill cleanup efficiency as a function of oil type, marsh type, and water depth

In-situ burning of spilled oil, which receives considerable attention in marine conditions, could be an effective way to cleanup wetland oil spills. An experimental in-situ burn was conducted to study the effects of oil type, marsh type, and water depth on oil chemistry and oil removal efficiency from the water surface and sediment. In-situ burning decreased the totaltargeted alkanes and total targeted polycyclic aromatic hydrocarbons (PAHs) in the burn residues as compared to the pre-burn diesel and crude oils. Removal was even more effective for short-chain alkanes and low ring-number PAHs. Removal efficiencies for alkanes and PAHs were >98% in terms of mass balance although concentrations of some long-chain alkanes and high ring-number PAHs increased in the burn residue as compared to the pre-burn oils. Thus, in-situ burning potentially prevents floating oil from drifting into and contaminating adjacent habitats and penetrating the sediment. In addition, in-situ burning significantly removed diesel oil that had penetrated the sediment for all water depths. Furthermore, in-situ burning at a water depth 2 cm below the soil surface significantly removed crude oil that had penetrated the sediment. As a result, in-situ burning may reduce the long-term impacts of oil on benthic organisms.     

Assessing the bioavailability of complex petroleum hydrocarbon mixtures in sediments

Several experimental methods have been developed to assess the bioavailability of individual organic compounds. So far none of them has however been applied to complex mixtures, such as oil (petroleum hydrocarbons), which is an ubiquitous pollutant. In the present study, we tested the potential of five of these experimental methods and that of a model approach to predict bioaccumulation of oil in the aquatic worm Lumbriculus variegatus exposed to 14 field-contaminated sediments. Actual and predicted bioaccumulation were compared in terms of both total bioaccumulative petroleum hydrocarbon concentrations and the relative distribution pattern of separate boiling point fractions (hydrocarbon blocks). None of the experimental methods was able to directly assess bioaccumulation in L. variegatus and correction factors were needed to match predicted and actual concentrations. These factors appeared concentration-dependent for solid phase micro extraction (SPME) and extractions with Tenax and cyclodextrin, most probably due to artifacts. Moreover, the hydrocarbon block pattern produced by these methods considerably differed from the pattern observed for worms; an additional reason for disqualification also applying to headspace-SPME. In contrast, the pattern produced by polyoxymethylene solid phase extraction (POM-SPE) closely mimicked the worm pattern and a sediment, hydrocarbon block, and concentration-independent correction factor (17) could be derived, based on which actual bioaccumulation could be predicted within a factor of 3. Finally, the model predicted bioaccumulation directly within a factor of 2. The accompanying hydrocarbon block pattern however deviated significantly more from the worm pattern than the POM-SPE pattern did. We therefore conclude that POM-SPE may be the overall best approach for predicting bioaccumulation of complex hydrocarbon mixtures in aquatic worms, all the more since an experimental approach will implicitly capture all factors determining bioavailability, which may prove difficult through a modeling approach.     

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

More than 200 oil samples were collected along the Northern Spanish coast, from December 2002 to December 2003, as part of the extensive monitoring program carried out by the Spanish Marine Safety Agency after the Prestige heavy oil spill (November 13, 2002). The GC FPD/ FID and comprehensive GC x GC/TOFMS sample profiles revealed the main characteristics of the oil residues. Chemical fingerprinting of the aliphatic and aromatic fractions by GC/ MS was performed to determine the source of the oil as well as to follow its weathering at sea. The (n-C13 + n-C14)/(n-C25 + n-C26), n-C18/phytane, and methylnaphthalene [(N + N1)/N2] ratios were found to be useful for assessing the evaporation, biodegradation, and dissolution processes, respectively. Other indicators of more advanced degradation processes, including photo-oxidation, were unaltered, showing the low incidence of natural weathering processes on the spilled heavy oil 1 year after the accident. The survey also demonstrated the occurrence of continued discharges of ballast waters at sea and the need for a more stringent surveillance of the area, beyond accidental oil spills.     

世界制造技术与装备领域三十年来的四大质变

世界范围现代制造技术与装备的演变日新月异,但从哲学范畴来观察分析,属于“量变”者居多,而属于“质变”的则百年难遇。然而最近三十年来,世界制造技术与装备领域至少出现了四大质变,值得我们特别关注。所谓“质变”是指：①创新思维与传统的“量变”有根本的区别;②所依托的物质载体与常规的相比在原理上有本质的差异;③在人类的生产活动中所形成的效益与影响,更为广泛而深远。     

Monitoring polycyclic aromatic hydrocarbon pollution in the marine environment after the Prestige oil spill by means of seabird blood analysis

In this study we tested the use of seabird blood as a bioindicator of polycyclic aromatic hydrocarbon (PAH) pollution in the marine environment. Blood cells of breeding yellow-legged gulls (Larus michahellis) were able to track spatial and temporal changes consistent with the massive oil pollution pulse that resulted from the Prestige oil spill. Thus, in 2004, blood samples from yellow-legged gulls breeding in colonies that were in the trajectory of the spill doubled in theirtotal PAH concentrations when compared to samples from unoiled colonies. Furthermore, PAH levels in gulls from an oiled colony decreased by nearly a third in two consecutive breeding seasons (2004 and 2005). Experimental evidence was gathered by means of an oil-ingestion field experiment. The total concentration of PAHs in the blood of gulls given oil supplements was 30% higher compared to controls. This strongly suggested that measures of PAHs in the blood of gulls are sensitive to the ingestion of small quantities of oil. Our study provides evidence that seabirds were exposed to residual Prestige oil 17 months after the spill commenced and gives support to the nondestructive use of seabirds as biomonitors of oil pollution in marine environments.     

Optimizing detection limits for the analysis of petroleum hydrocarbons in complex environmental samples

To evaluate the sources, transport, bioremediation, fate, and effects of spilled petroleum and petroleum products, environmental studies often measure parent and alkylated polycyclic aromatic hydrocarbons (PAH), alkanes, and chemical biomarkers (e.g., triterpanes). Accurate data for low analyte concentrations are required when environmental samples contain hydrocarbons from multiple sources that need to be resolved and quantified. The accuracy and usefulness of the analyses can be improved by lowering the method detection limits (MDLs) for these compounds. Misidentification of hydrocarbon source can result when the MDLs are too high. Modifications to standard analytical methods (i.e., U.S. Environmental Protection Agency Method 8270) can lower MDLs by factors ranging from 10 to 1000. This reduction has important implications for ecological-risk assessments. Modifications having the greatest impact on the MDL include GCMS analysis in the selected-ion-monitoring mode (SIM), increased sample size, column cleanup of the extract, and decreased preinjection volume (volume of final extract prior to injection into instrument). In one study in which a benthic sediment sample was spiked with low levels of topped (heated to remove more volatile PAH that are naturally enriched in crude oil) Alaska North Slope crude, MDLs for individual PAH analytes and biomarkers were determined to be less than 0.5 ng/g (ppb) dry weight and less than 5 ppb dry weightfor individual alkanes. Similar results were obtained when the sediment was spiked with the 16 EPA priority pollutants. In addition, a method has been developed to estimate MDLs for source-specific alkylated PAH analytes and chemical biomarker compounds for which standards are not commercially available or are prohibitively expensive. These improved analytical techniques have been used to identify and quantify low levels of hydrocarbons, derived from both natural and anthropogenic sources, found in the benthic sediments of Prince William Sound, AK.