Airborne mercury pollution from a large oil spill accident on the west coast of Korea

Atmospheric mercury pollution was recognized after a large oil spill on the west coast of Korea on 7 December 2007. In this study, the concentrations of gaseous elemental mercury (GEM: Hg(0)) in air were measured both shortly after the oil spill ( approximately 100h) and 1month after the accident near the accident site. When the Hg concentration levels were compared between two seashore sites and two parallel sites offshore, the values tend to decrease further offshore. The unusual rise in Hg concentration levels observed on the seashore area shortly after the accident (mean of 16.4+/-9.85ngm(-3)) dropped dramatically after 1month with active cleanup activities (2.99+/-1.40ngm(-3)). Because of the connection between crude oil and Hg (one of the major impurities), the unusual rise in the atmospheric Hg after the oil spill can be explained by the active evasion of Hg from the spilled crude oil. Although Hg levels determined a few days after the accident did not exceed the reference exposure limits (REL) proposed by several agencies, the early build-up of elemental mercury level due to the oil spill might have exerted certain impacts on the surrounding environments.     

Effect of operational parameters on the recovery rate of an oleophilic drum skimmer

The primary objective of this research was to determine the relationship between operational variables and oil spill recovery rates, by performing a full-scale oil spill recovery test using an oleophilic drum skimmer. Prototype interchangeable oleophilic skimmer drums with aluminum, polyethylene and Neoprene surfaces were fabricated and tested at the field scale at the Ohmsett-National Oil Spill Response Test Facility. This study determined the effect of the recovery surface material, oil properties, oil slick thickness, temperature and drum rotational speed on the oleophilic drum skimmer recovery rates. It was found that the selection of the recovery surface material can increase the recovery rates up to 20%. The increase in oil slick thickness from 10 to 25 mm led to up to two times higher recovery rates for a viscous oil, but did not have any noticeable effect on the recovery rates of light oil.     

Barrel‐Shaped Oil Skimmer Designed for Collection of Oil from Spills

Superhydrophobic–superoleophilic (SS) materials have the prospect to be used in oil‐spill cleanup as treated felts because of their complete oil‐absorbing and water‐repelling properties. The main issues affecting the practical application of the SS materials are the low volume‐based absorption capacity (resulting in a high cost), the requirement for mechanical handling (squeeze out the oil) for recycling, and low storage stability of the collected oil. In this study, a barrel‐shaped oil skimmer mainly composed of an SS Cu foam and a glass barrel is developed as a potential step‐change device to enable separation of oil and water. The SS Cu active component is fabricated by chemical etching and stearic acid modification. The demonstrator oil skimmer quickly and selectively absorbs and collects a variety of oils from a polluted water surface, showing a high separation efficiency and volume‐based absorption capacity. The device can be easily scaled up. In addition to the high absorption capacity, the as‐prepared oil skimmer filters and collects the floating oil into the barrel, removing the traditional mechanical handling. Moreover, the as‐prepared oil skimmer also shows good storage stability; no oil escapes from the skimmer under harsh conditions. The findings presented in this study facilitate a novel, simple, and low‐cost approach for oil‐spill cleanup.     

Biophysical Phenotyping and Modulation of ALDH+ Inflammatory Breast Cancer Stem‐Like Cells

Cancer stem‐like cells (CSCs) have been shown to initiate tumorigenesis and cancer metastasis in many cancer types. Although identification of CSCs through specific marker expression helps define the CSC compartment, it does not directly provide information on how or why this cancer cell subpopulation is more metastatic or tumorigenic. In this study, the functional and biophysical characteristics of aggressive and lethal inflammatory breast cancer (IBC) CSCs at the single‐cell level are comprehensively profiled using multiple microengineered tools. Distinct functional (cell migration, growth, adhesion, invasion and self‐renewal) and biophysical (cell deformability, adhesion strength and contractility) properties of ALDH+ SUM149 IBC CSCs are found as compared to their ALDH? non‐CSC counterpart, providing biophysical insights into why CSCs has an enhanced propensity to metastasize. It is further shown that the cellular biophysical phenotype can predict and determine IBC cells' tumorigenic ability. SUM149 and SUM159 IBC cells selected and modulated through biophysical attributes—adhesion and stiffness—show characteristics of CSCs in vitro and enhance tumorigenicity in in vivo murine models of primary tumor growth. Overall, the multiparametric cellular biophysical phenotyping and modulation of IBC CSCs yields a new understanding of IBC's metastatic properties and how they might develop and be targeted for therapeutic interventions.     

Life in oil: Hydrocarbon-degrading bacterial mineralization in oil spill-polluted marine environment

The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which an oil spill is eliminated from contaminated sites. One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2, 1997. This paper describes the three main processes of the Nakhodka oil spill, including: (1) the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas) and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years; (2) the laboratory-scale biodegradation of the Nakhodka oil spill over a 429-day period; and (3) the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill.Upon the slow evaporation of the Nakhodka oil spill during the 9-year weathering, the dendritic crystal growth of paraffin (a mixture of alkanes) occurred in the oil crust under natural conditions. Heavy metals were obtained in the original heavy oil samples of three seashores in the Sea of Japan. Si, S, Ti, Cr, Ni, Cu, and Zn were found in the original Nakhodka oil spill samples whereas these heavy metals and S were no longer present after 9 years. The anaerobic reverse side of the oil crust contained numerous coccus-type bacteria associated with halite. The hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation.A biodegradation process of heavy oil from the Nakhodka oil spill by indigenous microbial consortia was monitored over 429 days in the laboratory. The indigenous microbial consortia consisted of bacteria and fungi as well as the bacterium Pseudomonas aeruginosa isolated from Atake seashore, Ishikawa Prefecture, Japan. Both bacteria and fungi had a significant role in the observed biodegradation of heavy oil during the 429-day bioremediation with respect to the pH of the solution. Hydrocarbon-degrading bacteria had a tendency to play the greatest role under neutral to alkaline condition (pH; 7–7.8). On the contrary, when pH shifted to acidic (pH; 2–4) levels, the fungi took over to degrade heavy oil. During the period, the aliphatic hydrocarbons were reduced significantly but the aromatic hydrocarbons remained relatively constant even after 429 days of bioremediation.Experimental study was undertaken to investigate the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill. TEM/EDS imaging suggested that the clays present in oil-polluted seawater were capable of stimulating oil-degrading bacteria probably because Si from clays facilitates bacterial usage of oil and C-O-Na-Si complexes on the surfaces of bacterial cell walls are a stimulator for oil-degrading bacterial growth in seawater contaminated with the Nakhodka oil spill.     

Ultrasonic integrated backscatter coefficient profiling of human coronary arteries in vitro

A theoretical formulation for the profile of the integrated backscatter coefficient (IBC) is derived. This new formulation is based on a theoretical treatment. It includes correction for the diffraction of the ultrasonic beam and correction for the non-ideal nature of the reference signal. The inclusion of these correction factors permits accurate quantitative profiling of the IBC over the transducer focal zone. Experimental measurements are first performed on well-calibrated vessel-equivalent phantom materials and subsequently on human coronary arteries in vitro. A spherically focused 50.0 MHz f/1.83 transducer is used. IBC profiles are shown for three samples that are representative of early, mid, and advanced atherosclerotic coronary disease. The IBC profiles clearly differentiate the arterial tissues. However, variation between samples with histologically confirmed intimal thickening (N=24) was large. The mean IBC (±1 standard deviation), in (Sr.mm)^-1, for media, adventitia, and thickened intima were 3.86×10^-3, 1.53×10^-2, and 2.24×10^-2, respectively. The mean IBC of thickened intima is larger than previous measurements obtained from femoral arteries, and the mean IBC for media and adventitia layers are lower, reflecting differences in tissue composition between coronary and femoral vessels     

Two-phase stopped-flow measurement of the protonation of tetraphenylporphyrin at the liquid-liquid interface

The formation rate of the protonated form of tetraphenylporphyrin (TPP) in a dispersed two-phase system composed of dodecane and aqueous trichloroacetic acid (TCA) was studied by means of a stopped-flow method. The protonation reaction took place at the liquid-liquid interface, and the diprotonated TPP (H(2)TPP(2+)) formed was adsorbed there. In order to determine the rate-determining process, changes in absorbance at the absorption maximum wavelengths of TPP and H(2)TPP(2+) were analyzed. The obtained rate constant for the decrease of TPP in the organic phase, 21 ± 2 s(-1), was in agreement with that for the increase of diprotonated TPP at the interface, 20 ± 3 s(-1). The observed rate constants did not show any dependence on concentrations of both TPP and the acid. The experimental results suggested the rate-determining step to be the molecular diffusion process of TPP in the stagnant layer in the organic phase side at the liquid-liquid interface, and the thickness of the stagnant layer was estimated as 1.4 × 10(-4) cm.     

Incidents/accidents classification and reporting in Statoil

Based on requirements in the new petroleum regulations from Norwegian Petroleum Directorate (NPD) and the realisation of a need to improve and rationalise the routines for reporting and follow up of incidents, Statoil Exploration & Production Norway (Statoil E&P Norway) has formulated a new strategy and process for handling of incidents/accidents. The following past experiences serve as basis for the changes made to incident reporting in Statoil E&P Norway; too much resources were spent on a comprehensive handling and analysis of a vast amount of incidents with less importance for the safety level, taking the focus away from the more severe and important issues at hand, the assessment of "Risk Factor", i.e. the combination of recurrence frequency and consequence, was difficult to use. The high degree of subjectivity involved in the determination of the "Risk Factor" (in particular the estimation of the recurrence frequency) resulted in poor data quality and lack of consistency in the data material. The new system for categorisation and handling of undesirable incidents was established in January 2002. The intention was to get a higher degree of focus on serious incidents (injuries, damages, loss and near misses), with a thorough handling and follow-up. This is reflected throughout the handling of the serious incidents, all the way from immediate notification of the incident, through investigation and follow-up of corrective and preventive actions. Simultaneously, it was also an objective to rationalise/simplify the handling of less serious incidents. These incidents are, however, subjected to analyses twice a year in order to utilize the learning opportunity that they also provide. A year after the introduction of this new system for categorisation and follow-up of undesirable incidents, Statoil's experiences are predominantly good; the intention to get a higher degree of focus on serious incidents (injuries, damages, loss and near misses), has been met, the data quality for the more serious incidents (5% of the total number of incidents registered) has improved, the improved handling of incidents has contributed to more reliable and accurate HSE indicators at a corporate level, more user friendly codes in place for incident registration (based on MTO methodology), the revised matrix gives distinct criteria with respect to which investigation level to be initiated for a specific incident. All activities related to handling of undesirable incidents have been summarised and illustrated on a two-sided plastic form, incorporating both the categorisation matrix and the activity flowchart (see Figs. 1 and 4).     

中散包装与危险品包装生命周期评价比较研究

对中散包装与危险品包装生命周期进行了评价研究。利用Simapro 软件对2 种固体危险货物包装形式———一般包装(瓦楞纸箱)和中型散装容器(纤维板箱IBC)进行了生命周期分析,并将结果进行了对比。可以看出中型散装容器与一般包装相比优势明显,在分析所涉及的11 个环境类别的影响上均小于一般包装,其中,差距最大的为臭氧层耗竭损害,仅为一般包装的60%,最小的为酸化/ 富营养化,为一般包装的90%。结果显示IBC 优势明显,在大量货物运输的过程中,若2 种包装类型均能达到运输效果,应选取对环境影响较小的IBC 进行运输。     

In-depth analysis of accidental oil spills from tankers in the context of global spill trends from all sources

This study gives a global overview of accidental oil spills from all sources (> or =700t) for the period 1970-2004, followed by a detailed examination of trends in accidental tanker spills. The present analysis of the number and volume of tanker spills includes temporal and spatial spill trends, aspects of spill size distribution as well as trends of key factors (i.e., flag state, hull type, tanker age, accident cause and sensitivity of location). Results show that the total number and volume of tanker spills have significantly decreased since the 1970s, which is in contrast to increases in maritime transport of oil and to popular perceptions following recent catastrophic events. However, many spills still occur in ecologically sensitive locations because the major maritime transport routes often cross the boundaries of the Large Marine Ecosystems, but the substantially lower total spill volume is an important contribution to potentially reduce overall ecosystem impacts. In summary, the improvements achieved in the past decades have been the result of a set of initiatives and regulations implemented by governments, international organizations and the shipping industry.     

聚光背结背接触太阳电池发射区半宽度的优化研究

利用TCAD半导体器件仿真软件对中低倍聚光光伏系统中应用的N型叉指背接触(IBC)单晶硅太阳电池的电学性能进行了仿真研究。全面系统地分析了在不同聚光比情况下,单元电池发射区半宽度对聚光IBC太阳电池短路电流密度、开路电压、填充因子及转换效率的影响。仿真结果表明:聚光IBC太阳电池的电学性能受到单元电池发射区半宽度和聚光比的显著影响。在不同的聚光比情况下,存在最优的发射区半宽度,使得聚光IBC太阳电池转换效率最高。随着聚光比的增大,最优的发射区半宽度减小。虽然增大聚光比可提高聚光IBC太阳电池的转换效率,但同时减小了最优的发射区半宽度及参考范围,增加了聚光IBC太阳电池的制备难度。     

Bio-electrospraying and aerodynamically assisted bio-jetting the model eukaryotic Dictyostelium discoideum: assessing stress and developmental competency post treatment

Bio-electrospraying (BES) and aerodynamically assisted bio-jetting (AABJ) have recently been established as important novel biospray technologies for directly manipulating living cells. To elucidate their potential in medical and clinical sciences, these bio-aerosol techniques have been subjected to increasingly rigorous investigations. In parallel to these studies, we wish to introduce these unique biotechnologies for use in the basic biological sciences, for handling a wide range of cell types and systems, thus increasing the range and the scope of these techniques for modern research. Here, the authors present the analysis of the new use of these biospray techniques for the direct handling of the simple eukaryotic biomedical model organism Dictyostelium discoideum. These cells are widely used as a model for immune cell chemotaxis and as a simple model for development. We demonstrate that AABJ of these cells did not cause cell stress, as defined by the stress-gene induction, nor affect cell development. Furthermore, although BES induced the increased expression of one stress-related gene (gapA), this was not a generalized stress response nor did it affect cell development. These data suggest that these biospray techniques can be used to directly manipulate single cells of this biomedical model without inducing a generalized stress response or perturbing later development.     

Experimental study of the spill and vaporization of a volatile liquid

Pool and vapor cloud characteristics of an acetone spill issuing from the downstream wall of a flow obstruction oriented perpendicular to a uniform flow were investigated experimentally. Data indicate that the spill event was largely governed by the temperature of the surface in relation to the boiling point of the spilled liquid. The free stream velocity (ranging from 0.75 to 3.0m/s) also impacted the spreading of the spill. Planar laser-induced fluorescence (PLIF) was used to measure acetone vapor concentrations during the transient pool spreading and vaporization in a window 60cm long by 50cm high and located downstream of the 16cm high obstruction. The recirculation region induced by the flow obstruction caused upstream transport of the acetone vapor along the spill surface, after which it was convected vertically along the obstruction wall before being entrained into the flow and convected downstream. The recirculating flow caused regions of vapor within the flammability limits to be localized near the flow obstruction. These regions moved into and out of the measurement plane by large three-dimensional flow structures. The flammable region of the evolved vapor cloud was observed to grow well past the downstream edge of the measurement domain. With decreasing wind speeds, both the mass of acetone vapor within the flammability limits and the total spill event time increased significantly. The data presented herein provides a basis for validating future spill models of hazardous chemical releases, where complex turbulent flow modeling must be coupled with spill spreading and vaporization dynamics.     

Life in oil: Hydrocarbon-degrading bacterial mineralization in oil spill-polluted marine environment

The biodegradation of hydrocarbons by microorganisms is one of the primary ways by which an oil spill is eliminated from contaminated sites. One such spill was that of the Russian tanker the Nakhodka that spilled heavy oil into the Sea of Japan on January 2, 1997. This paper describes the three main processes of the Nakhodka oil spill, including: (1) the weathering of hydrocarbon-degrading bacteria (genus Pseudomonas) and crystallized organic compounds from the Nakhodka oil spill-polluted seashores after nine years; (2) the laboratory-scale biodegradation of the Nakhodka oil spill over a 429-day period; and (3) the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill. Upon the slow evaporation of the Nakhodka oil spill during the 9-year weathering, the dendritic crystal growth of paraffin (a mixture of alkanes) occurred in the oil crust under natural conditions. Heavy metals were obtained in the original heavy oil samples of three seashores in the Sea of Japan. Si, S, Ti, Cr, Ni, Cu, and Zn were found in the original Nakhodka oil spill samples whereas these heavy metals and S were no longer present after 9 years. The anaerobic reverse side of the oil crust contained numerous coccus-type bacteria associated with halite. The hydrocarbon-degrading bacteria and paraffin wax in the oil crust may have a significant effect on the weathering processes of the Nakhodka oil spill during the 9-year bioremediation. A biodegradation process of heavy oil from the Nakhodka oil spill by indigenous microbial consortia was monitored over 429 days in the laboratory. The indigenous microbial consortia consisted of bacteria and fungi as well as the bacterium Pseudomonas aeruginosa isolated from Atake seashore, Ishikawa Prefecture, Japan. Both bacteria and fungi had a significant role in the observed biodegradation of heavy oil during the 429-day bioremediation with respect to the pH of the solution. Hydrocarbon-degrading bacteria had a tendency to play the greatest role under neutral to alkaline condition (pH; 7–7.8). On the contrary, when pH shifted to acidic (pH; 2–4) levels, the fungi took over to degrade heavy oil. During the period, the aliphatic hydrocarbons were reduced significantly but the aromatic hydrocarbons remained relatively constant even after 429 days of bioremediation. Experimental study was undertaken to investigate the bioavailability of kaolinite clay minerals and the role they play in seawater polluted with the Nakhodka oil spill. TEM/EDS imaging suggested that the clays present in oil-polluted seawater were capable of stimulating oil-degrading bacteria probably because Si from clays facilitates bacterial usage of oil and C-O-Na-Si complexes on the surfaces of bacterial cell walls are a stimulator for oil-degrading bacterial growth in seawater contaminated with the Nakhodka oil spill.     

Modeling evaporation using models that are not boundary-layer regulated

Experimentation shows that oil is not strictly air boundary-layer regulated. The fact that oil evaporation is not strictly boundary-layer regulated implies that a simplistic evaporation equation suffices to describe the process. The following processes do not require consideration: wind velocity, turbulence level, area, thickness, and scale size. The factors important to evaporation are time and temperature. The equation parameters found experimentally for the evaporation of oils can be related to commonly available distillation data for the oil. Specifically, it has been found that the distillation percentage at 180 degrees C correlates well with the equation parameters. Relationships have been developed enabling calculation of evaporation equations directly from distillation data: percentage evaporated = 0.165 (%D)ln(t) where %D is the percentage (by weight) distilled at 180 degrees C and t is the time in minutes. These equations were combined with the equations generated to account for the temperature variations: percentage evaporated = [0.165(%D)+0.045(T-15))ln(t) The results have application in oil spill prediction and modeling. The simple equations can be applied using readily available data such as sea temperature and time. Old equations required oil vapour pressure, specialized distillation data, spill area, wind speed, and mass transfer coefficients, all of which are difficult to obtain.     

Validation of methylmercury determinations in aquatic systems by alkyl derivatization methods for GC analysis using ICP-IDMS

Isotope dilution mass spectrometry (IDMS), using an inductively coupled plasma quadrupole mass spectrometer (ICPMS) and a species-specific methylmercury spike was applied to validate the commonly used GC method for methylmercury (MeHg+) determination, which is based on the formation of volatile methylethylmercury by derivatizationwith NaBEt4. The spike compound, Me201Hg+, was synthesized by reaction of 201Hg-enriched mercury chloride with methylcobalamin. By analyzing different environmental aquatic samples, it was found that in most cases, transformation of MeHg+ into elemental mercury (Hg0) took place. From investigations of synthetic solutions, it could be followed that halide ions are responsible for this transformation process. Chloride and bromide converted MeHg+ into Hg0, whereas iodide caused transformation into Hg2+ and Hg0. It could also be shown that transformation of MeHg+ took place only during the derivatization step. In contrast to ethylation, propylation by NaBPr4 did not cause any transformation; however, accurate results of MeHg+ determinations could be obtained by propylation as well as by ethylation when GC/ ICP-IDMS was applied. This work demonstrates the great power of isotopically labeled element compounds for the validation of element speciation methods and for species-specific IDMS analyses.     

Weathering of a subarctic oil spill over 25 years: the Caribou-Poker Creeks Research Watershed experiment

A small experimental oil spill conducted in an open black spruce forest within the Caribou-Poker Creeks Research Watershed (CPCRW), 48 km north of Fairbanks, AK, in the winter of 1976 was designed to examine the effects of crude oil spills in permafrost terrain. No clean-up was attempted, and the site now provides an opportunity to follow the natural weathering of spilled oil under these conditions. In summer 2001, more than 25 years after the spill, we sampled soils from the spill plot and a nearby reference plot to determine how the oil had weathered, and to assess microbial populations and activity. All samples collected from the oiled plot contained substantial amounts of methylene chloride extractable oil, between 4% and 66% by weight. Using 17α(H)21β(H)hopane as a conserved internal marker within the oil, we determined that while some heavily oiled samples were almost unchanged since the spill, others had lost more than 80% of their initial hydrocarbon. Evaporation, biodegradation and photooxidation all seem to have played important roles in this process, but to varying degrees in different samples. Assays of culturable populations of total heterotrophs and crude oil emulsifiers, and mineralization potentials for hexadecane and phenanthrene, indicate that the microbial population in the oiled soils has remained acclimated to degrade hydrocarbons. We conclude that natural weathering processes will eventually lead to the removal of much of the hydrocarbon from these heavily oiled subarctic soils; however, the combination of low rates of nutrient turnover, a short thaw season, and high hydrocarbon concentrations will result in the persistence of oil residue for many more decades. Finding an environmentally appropriate cleanup technology for sites like this remains an important challenge for future research.     

A high-level synthesis of oil spill response equipment and countermeasures

This paper presents an operational synthesis of major oil spill response methods (mechanical, chemical, etc.) and the corresponding oil response equipment for sea context (booms, skimmers, etc.). We focus on important features of oil spill response, in order to formulate a decision-based database, capable of supporting the development of a complete oil spill response operation. Moreover, we classify these findings and introduce simple formatting and standards to supply predictive tools for oil spill models. The actual goal of this paper is to come up with a decision-driven process, which can provide for a realistic choice of oil spill response equipment in the design of the primary oil response phase. This is intended to lead to a prompt, logical, and well-prepared oil spill response operation satisfying time and cost criteria and protecting the marine environment.     

Potential of NMR spectroscopy for the study of human amniotic fluid

1D and 2D 800 MHz high-resolution nuclear magnetic resonance spectroscopy of human amniotic fluid (HAF) enabled the identification of approximately 50 metabolites. In addition, liquid chromatography-NMR and diffusion ordered spectroscopy (DOSY) allowed signal overlap to be reduced and the characterization of higher molecular weight (Mw) components, respectively. Indeed, the DOSY spectrum of a Mw >10 kDa HAF fraction enabled three protein families, differing in average Mw, to be detected and may therefore be of potential value in the study of disorder-related variations in HAF protein profiles. The effects of freeze-drying, storage at -20 or -70 degrees C, and freeze-thawing cycles on HAF compositional stability were investigated, as well as stability at room temperature (to account for overnight data acquisition runs). These data are the basis for establishing statistically validated correlations between HAF NMR data and any physiological disorders of the fetus/mother. Freeze-drying caused signal loss for urea, ethanol, and compounds resonating at 2.22 and 1.17 ppm. Storage at -70 degrees C or lower is recommended since only minor compositional changes were observed, affecting mainly acetate and pyruvate. Freeze-thaw cycles did not cause significant compositional changes, and room-temperature stability studies indicated a 4-5 h maximum period of handling/acquisition time to ensure HAF stability.