Journal articles on the topic 'Spilled oils'

Oil spill; Source identification; δ15N; Nitrogen isotope profile; biodegradation Abstract. A preliminary evaluation of nitrogen isotope analysis as a novel, alternative method for identifying spilled oils is presented. The nitrogen isotopic compositions of crude oil from different oilfields in China may be significantly different, which provides a way of screening possible sources for spilled oil of unknown origin, especially in areas of heavy tanker traffic carrying oils from different geographical regions. The value of δ15N increases gradually with the degree of biodegradation. This findings can be applied for correlation and differentiation of spilled oils at their lightly to moderately weathered stages.

ABSTRACT Like conventional, lighter-than-water oils, heavy oils that sink or become suspended in water when spilled can cause damage to the environment, threaten human health, and adversely affect economic resources. The behavior of heavy oil in water complicates aspects of spill response including location, mapping and containment of spilled oil; assessment of environmental and economic impacts; responder health and safety; prediction of oil movement; comparison of alternative response methods; and measurement and documentation of cleanup effectiveness. Experience shows that the techniques and equipment needed to respond to heavy oil spills are highly specific to the spill location and circumstances of the spill, accentuating the importance of preincident planning. Sound planning is one of the most important tools available for implementing an effective response to oil spills and minimizing their impacts. In this paper response strategies that have been utilized in nonfloating oil spills are examined, and the relative advantages and disadvantages of techniques and equipment employed in those incidents are discussed. The intent of this examination is to help emergency response planners recognize response methods that have worked under conditions they are likely to encounter so they can plan accordingly.

ABSTRACT The Emergency Response Notification System database was searched for information on the size of spills, the sources of spills, and the types of oils spilled for both inland and coastal waters. The results of this analysis indicate that the vast majority of spills for both inland and coastal waters are minor discharges, that the sources of the spills differ for inland versus coastal waters, with pipelines representing a minor source for both water systems, and that a wide variety of materials are spilled in both inland and coastal water systems, with crude oil being a more significant contributor for coastal waters.

ABSTRACT When an oil spill occurs, there is an immediate need on the part of spill responders to know the properties of the spilled oil, as these will affect the behavior, fate, and effects of the oil, which will in turn affect the choice of countermeasures. However, it is often difficult or impossible to obtain a sample of the spilled oil, let alone the specialized analysis required to determine its properties, in a manner timely enough to suit the circumstances of an oil spill. Under the scrutiny of the media and the public, answers regarding the identity and predicted behavior of the spilled oil will be expected immediately, if not sooner. In preparation for such emergencies, the Emergencies Science Division (ESD) of Environment Canada has been collecting properties data for crude oils and oil products since 1984. Basic physical properties—density, viscosity, pour point, etc.—and environmentally relevant characteristics—evaporation rates, emulsion formation, chemical dispersibility—are measured. Properties related to health and safety—flash point, volatile organic compounds, sulfur—also are determined. In fact, nearly 20 different types of measurements are made for both fresh and weathered crude oils and oil products. To date data has been collected for more than 400 oils. For ease of access, this information is stored in an electronic database. The database in turn is accessible via the World Wide Web, and is also periodically printed in an easy-to-read catalogue format. The wide variety of data collected in the database also makes it possible to examine both simple and complex relationships that may exist between oil properties and spill behavior. This presentation will review the full scope of information determined and collected by ESD. Using tables and graphs, examples will be presented of the many ways in which this information can be viewed and used by both laymen and experts in the field of oil spills.

ABSTRACT The chemical composition and physical properties of a crude oil determine the behavior of the oil and the way its properties will change when the oil is spilled at sea. Reliable knowledge of the oil's behavior will enable the most effective countermeasure techniques to be used in a spill situation. A diverse range of crude oils is coming into production in the North Sea. The weathering behavior and chemical dispersibility of three very different crude oils—Troll (naphthenic), Balder (asphaltenic), and Nome (waxy)—have recently been thoroughly investigated through bench- and meso-scale experiments. The naphthenic crude oil was also exposed to full-scale studies in the North Sea. This study shows that emulsion formation, the viscosity of emulsion, and the potential for dispersing emulsions by dispersant treatment may vary greatly for the different crude oils. It would be impossible to predict these differences with existing oil-weathering models based on fresh oil properties alone. Especially for abnormal (e.g., highly asphaltenic, waxy) crude oils, the weathering and dispersibility behavior can be revealed only by experimental work. The findings have important implications for effective oil spill response planning, particularly for estimating the most appropriate “window of opportunity” and for optimizing a dispersant application strategy for crude oils.

Precisely and rapidly determining the sources of spilled oils, which has posed threats to wildlife, human beings, and the natural environment, can provide scientific evidence for the investigation and handling of spilled oil accidents.

ABSTRACT 2017-054 The 2016 American Petroleum Institute inland guide incorporates lessons learned from spill responses that can minimize the environmental impacts of inland oil spills. In addition, it provides new information on the changing risk profiles of inland spills in North America. such as the increase in oil transportation by rail, the added risks of fire and air quality concerns from spills of very light crude oils from light tight shale production areas, behavior of diluted bitumen products when spilled to fresh water, and special considerations for inland spill response. Best practices for inland oil spill response are organized by Oil Groups 1–4 and Group 5 submerged oil (oil that is suspended in the water column or moving along the bottom). It provided guidance on selecting appropriate cleanup endpoints for inland spills. Finally, it provides response guidelines for issues of special concern for inland spills, including: protection of water intakes, response to spills of ethanol-blended fuels, air quality monitoring and levels of concern, oil field produced waters, treatment of oiled debris, and fast-water booming strategies.

ABSTRACT Chronic oil spills at junkyards are being overlooked, but they can cause serious economic and environmental problems. Long considered non-hazardous, motor oils, automobile fluids, industrial waste oils and solid wastes are spilled daily at scrap metal yards across the nation. These chronic spills can carry heavy metals and toxic wastes off site through surface drains, soil penetration, and track out. Intermixed with oil, these wastes are complex and costly to clean up. Superfund cleanup actions at former junkyards are only part of the economic burden to the public. Quality of life and property value problems add to the host community's roadblocks to redevelopment, and also to their list of brownfields. Relaxed attitudes in handling liquid and solid wastes at these sites, along with ignorance of environmental rules, seem to be at the root of the problem. It is suggested that local agencies get involved in monitoring waste management practices, as well as try outreach efforts to educate junkyard operators in oil spill prevention and waste management.

Oil pollution in the marine environment has now become a world-wide concern. Recently, in Japan, over 1,000 cases of oil pollution have been occurring every year. It is important to develop an effective identification method for spilled oils for conservation of marine environments. A new method was developed using high performance gel permeation chromatography (GPC). Chromatograms of the molecular weight distribution of oils were obtained using an ultra-violet (UV) detector. Pattern similarities between pairs of chromatograms were calculated by section areas of the chromatograms using a computer. Sixty two kinds of crude oil imported by Japan were classified by this method, and a close relationship was found between the countries of origin of the crude oils and their chromatographic patterns. Forty nine tar balls sampled from Japanese coasts were compared with the crude oils, and the origins of the tar balls were deduced. The proposed method was effective for the identification of spilled oils, and had high sensitivity and reproducibility.

ABSTRACT A research project was commissioned by the American Petroleum Institute (API) to summarize information on freshwater spill environmental effects. While threats to migrating fish stocks or aquatic mammals may be primary concerns following an ocean spill, adverse effects to benthic invertebrates, reptiles, amphibians, waterfowl, fish hatcheries, shoreline vegetation, or public drinking water intakes may be the focus of a freshwater event. Environmental effects from spilled petroleum constituents and whole oils are discussed. Research needs are identified.

The fate of oil spilled on seawater is an important issue for marine environment. This paper studied the dissolution of two crude oils and the photodegradation of their water-soluble fraction (WSF). The relationship between the solubility and the component of the crude oils was studied by gas chromatograph, UV absorption and synchronous fluorescence spectrum, and the result indicated that the aromatic hydrocarbon was liable to dissolve in water and the dissolved organic matter (DOM) in seawater enhanced the dissolution of crude oils. Moreover, the photodegradation of WSF accorded with the pseudo-first order reaction, and the reaction rate constants for WSF 1 and 2 were 0.088 and 0.121 h-1, respectively. This investigation is helpful for better understanding the transformation of crude oil spilled on the sea.

Tar balls are frequently reported as indicators of the extent of marine pollution owing to spill incidents of crude oil or petroleum products. Representative tar ball samples collected on a beach on Žirje Island, Croatia, were geochemically characterised by gas chromatography coupled to mass spectrometry (GC/MS) in order to identify correlations between them and investigate potential sources. The chemical analysis of petroleum biomarkers, hopanes, and steranes, detected by gas chromatography/mass spectrometry (GC/MS) generates information of great importance to environmental forensic investigations in terms of determining the source of spilled oil, differentiating and correlating oils, and monitoring the degradation process and weathering state of oils under a wide variety of conditions. The chromatographic signatures of hopane and sterane biomarkers in tar ball samples from Žirje Island were compared. Characteristic hopane and sterane fingerprints show that all the tar ball samples originated from crude oil spills. This study indicates that, the major source of tar balls was likely to be the same type of crude oil as evident from the petroleum biomarker fingerprints.

Along with the increasing transport of crude oils to the refinery sites, many accidents of oil spills have been occurred in Indonesian waters. Such spills might be purely an accident but some others are suspected to be deliberately spilled. Nevertheless, both cases need an identification system to trace back the spill source and eventually the spill data can be brought to the court as an evident. Previously, the identification system was conducted through a pattern recognition of n-paraffin hydrocarbons of crude oil samples which are very distinguished from their gas chromatographic (GC) pattern of n-C17, Pristane, n-C18, Phytane, and other nparaffin’s down to n-C30. Unfortunately, some crude oils have similar pattern that matching of two chromatograms could give an ambiguity result. Pattern recognition of isoprenoid hydrocarbons have been developed to characterized crude oils that potentially pollute the Indonesian waters. Differing from the n-paraffin that each hydrocarbon peak can be determined definitely, the developed method does not need to identify each of the isoprenoid hydrocarbons, instead pattern of their chromatographic separation are sufficiently distinguished. GC isoprenoid pattern recognition is made from the isoprenoid peaks that emerge between n-C17 and n- 18. It two crude oils having similar pattern of n-paraffin’s show very distinct pattern of iso-paraffin’s. The method thus can be used as complimentary step in matching the GC pattern of crude oil samples . Although in some cases GC isoprenoid peaks are not completely separated, this would not be disadvantages since their retention time and area can be measured and integrated definitely, respectively. Nevertheless, the separation of iso-paraffin peaks can be easily conducted using a recent GC method namely a comprehensive two dimensional gas chromatography (GCxGC), a method which is recommended to be implemented further in this research.

ABSTRACT The use of oil spill dispersants is often regulated by national authorities to ensure that products approved for use as dispersants on spilled oil in national waters are of reasonable effectiveness and of low inherent toxicity. KING (Kazakh Institute of Oil & Gas) undertook a study to assess the use of oil spill dispersants on spilled oils in the Kazakhstan sector of the Caspian Sea (KSCS) to support decision-making for such regulations in the RoK (Republic of Kazakhstan). The KSCS has some characteristics that are unlike open ocean conditions in other parts of the world; the salinity is much lower than in the open sea. The shallow waters of the northern Caspian Sea have very low salinity (9 psu (practical salinity units) or less) due to the inflow of freshwater from the River Volga, and are frozen in winter. The deeper water in the southern part of the KSCS has a salinity of up to 14 psu. The effectiveness of oil spill dispersants is known to be affected by water salinity. Different countries around the world have developed different test methods to assess dispersant effectiveness. The project examined the options and decided to modify the WSL (Warren Spring Laboratory) LR 448 dispersant effectiveness test method, as used in the UK. The method was adapted by KING and testing was conducted by Karaganda State University (KSU) to test a variety of dispersants under Caspian Sea conditions. Dispersant effectiveness testing should be conducted with a test oil that is representative of oils that might be spilled in the area being considered. Kashagan crude oil was distilled to 200°C to simulate the evaporative loss that would occur shortly after the oil was spilled at sea and the residue used as the test oil in the dispersant effectiveness testing. Several commercially-available dispersants were tested using the modified LR 448 method with the 200°C+ Kashagan test oil under a variety of conditions with salinities ranging from 0 psu to 35 psu and at temperatures of 5°C and 25°C. The results indicate that some internationally recognized dispersants could be suitable for use in the KSCS.

ABSTRACT Most oil spill containment and recovery equipment is not suitable for use with heavy viscous crude oils. For these oils, nets have been suggested as a containment device, and some laboratory and open sea studies of their suitability have been conducted. We have used a trolley system in a large outdoor pool to measure net loading and to observe the behavior of nets in containing heavy neutrally buoyant oil (viscosity of 3 × 105 cSt at 10° C). For moderate towing speeds of about 0.3 meters per second, inexpensive ¼ inch mesh fish netting was found to be a suitable containment device.

ABSTRACT The ability to unambiguously identify spilled oils and petroleum products in complex contaminated environmental samples and to link them to the known sources is extremely important in settling questions of environmental impacts and liability. This paper will briefly review advanced chemical fingerprinting and data interpreting techniques used to identify sources of spilled oils. The chemical fingerprinting techniques discussed include pattern recognition evaluation of target petroleum hydrocarbon distributions; determination of major oil components and hydrocarbon groups; determination of diagnostic ratios of source-specific marker compounds such as PAHs and biomarkers; target PAH isomer analysis; and carbon isotopic ratio analysis. Methods for distinguishing biogenic and pyrogenic hydrocarbons from petrogenic hydrocarbons are also addressed. Several examples are presented to illustrate approaches to identifying and allocating multiple sources of hydrocarbons in complex hydrocarbon mixtures using these advanced chemical fingerprinting techniques.

It might seem incongruous that a research focused organisation such as the International Union for Pure and Applied Chemistry would pay attention to an issue as pragmatic as oil spills. After all, an oil spill tends to be viewed as a very practical matter, its issues characterised by loss of a valuable commercial product, damage to the environment, high costs of clean up, high legal liabilities, and very much media attention. Oil spills are not generally considered a pure or even applied chemistry issue. However, this would be a very short-sighted interpretation. Effectively every element of an oil spill, whether environmental, physical, operational or legal, is related to the complex chemistry of the oil and its breakdown products released to the environment. Indeed, it would be safe to say that if petroleum were a simple chemical product, the difficulties inherent in clean up of an oil spill would be much reduced, no matter what the origin or cause of the spill.The chemical nature of oil is directly related to the fate and environmental impacts of spilled oil, whether on water or on land, and to the effectiveness of the diversity of countermeasures which might be deployed. While evaluation of the effects of spilled oil on the environment receives much attention in forums with a biological or toxicological focus, which often do take into consideration chemical factors, the complex topic of the chemistry of oil spills in direct relation to countermeasures is examined more rarely. The various chapter in this document discuss a diversity of oil spill countermeasures, and target the chemical and consequently physical behaviour of oil which determines its characteristics at the time of the spill. While oil spills occur in fresh and salt waters, and on land, marine oil spills remain the larger issue - there tends to be more oil spilled, environmental problems are more complex, and countermeasures are more difficult to implement. The following papers generally reflect and review the current state of knowledge in their topic area, and are representative of the most recent surge in research and development activities, stimulated particularly by the Exxon Valdez spill in Prince William Sound, Alaska in 1989. It appears that oil spill research undergoes cycles of interest, activity and funding, linked to key oil spills. Previously, the Torrey Canyon spill in the English Channel off Land's End, in the United Kingdom in 1967 provided general incentive for research and development, as did the Amoco Cadiz spill off the coast of Brittany, France in 1978. Other oil spills, such as the 1968 Santa Barbara Channel, California spill, or the Braer spill off the Shetlands in 1993, among others, have also stimulated specific areas of research and development on the basis of issues that arose in their particular spill scenario.The articles in this publication have been contributed by recognised international experts in the spill response field, and have received the benefit of peer review. The articles are representative of the major categories of oil spill response research, spanning a wide range of technologies, supportive knowledge and experience, to include reviews of:This collection of review articles concludes with an evaluation of oil spill response technologies for developing nations, appropriately so since that is where much of the oil development and production currently occurs in the world.One area which has seen much recent expansion is that of the essential linkage between detailed understanding of spilled oil physical/chemical properties and the effectiveness of response countermeasures. Crude oils and oil products are known to differ greatly in physical and chemical properties and these tend to change significantly over the time course of spilled oil recovery operations. Such changes have long been recognised to have a major influence on the effectiveness of response methods and equipment, which increases the time and cost of operations and risk of resource damage. All countermeasures are influenced, whether sorbents, booms, skimmers, dispersants, burning of oil and so forth. The incentive is for a rapid and accurate method of predicting changes in oil properties following spill notification, which could be used in both the planning and early phases of spill response, including an initial specific selection of an effective early countermeasure. In later stages of the response, more accurate planning for clean up method and equipment deployment would shorten response time and reduce costs. An additional benefit would be more effective planning for recall of equipment not needed, as well as potentially decreasing the risk of natural resource damage and costs due to more effective spilled oil recovery. The concept of "Windows of Opportunity" for oil spill response measures has been derived from multiple investigations in industry and government research organisations.Although dispersants have been used to date in almost one hundred large spills world-wide, government approval for dispersant use has long been inhibited by a lack of understanding of the factors determining the operational effectiveness of dispersants, and the environmental trade-offs which might need to be made to protect sensitive areas from spilled oil. Recent advances in chemical dispersant development, formulation of low toxicity dispersants with broader application, and better understanding of dispersant fate and effects have combined to a more ready acceptance of this countermeasure by many, although not yet all, regulatory authorities throughout the world. In addition to the category of dispersants, chemical countermeasures include many diverse agents, such as beach cleaners, demulsifiers, elasticity modifiers and bird cleaning agents, each with a unique and specialised role in clean up activities. However, the concerns for the use of these 'alternative chemicals' relate to the interpretation and application of toxico-ecological data to the decision process. If in the future the ecological issues concerning chemical treating agents can be further successfully resolved, the oil spill response community will have an increased range of options for response. However, extensive laboratory and field testing is required in many instances for new chemical dispersant materials and demulsifiers to improve the effectiveness of these materials on weathered oils and water in oil emulsions. The acceptance of in situ (i.e. 'on site') burning of spilled oil has been limited by valid operational concerns about the integrity of fireproof booms, the limited weather window for burning due to the rapid emulsification of oils, the need to develop methods for the ignition of emulsified and weathered oils, and public concerns about the toxicity of the smoke generated during burning. However, burning provides an option, another tool in the tool-box, for the responder called in to combat an oil spill. Burning decreases the amount of oil that must be collected mechanically, thus reducing cleanup costs, storage, transportation, and oily waste disposal requirements. It also would decrease potential contact with sensitive marine and coastal environments and consequently reduce the potential for associated damage costs. Laboratory and field studies over the last ten years have addressed essential information requirements for feasibility, techniques, and effectiveness, as well as health and safety. The results of research in situ burning has led to its acceptance in a number coastal jurisdictions throughout the world, prompting the response industry to purchase and position in situ burning equipment and train its operators to use this alternative technology in approved regions.Although not a direct recovery measure in itself, the application of remote sensing to oil spill response assists in slick identification, tracking, and prediction, which in many instances is an early requirement for effective response. An inadequate ability to see spilled oil seriously reduces effectiveness of oil spill response operations. Conversely, good capability to detect spilled oil, especially areas of thick oil, at night and other conditions of reduced visibility could more than double response effectiveness and greatly enhance control of the spill to minimise damage, especially to sensitive shorelines. Advances have been made in both airborne and satellite remote sensing. It has become possible to move from large and expensive to operate airborne systems to small aircraft, more widely available and practical for spill response operators. Also, the limitations in delayed data processing and information communication are being overcome by development of systems operating in functional real-time, which is essential for enhanced response capacity. Spill detection using satellites has also advanced markedly since 1989, with the ongoing intention to provide coverage of oil spill areas as early warning, or when flying by aircraft is not possible. An early useful application was an ERS-1 satellite program for detection of oil slicks, launched in 1992. More recently, spill detection capability has been developed for the Canadian Radarsat satellites, ERS-2 and a few other satellite programs.The topic of bioremediation of spilled oil, that is, to use microbes to assist in clean up, is a corollary to the deployment of traditional countermeasures. It had not seen much operational or regulatory support until the Exxon Valdez spill, where it was initiated as a spill mitigation method, establishing bioremediation as a major oil spill R&D area. Bioremediation of oil spills was defined as being one of three different approaches: enhancement of local existing microbial fauna by the addition of nutrients to stimulate their growth; 'seeding' the oil impacted environment with microbes occurring naturally in that environment; and, inoculating the oil impacted environment with microbes not normally found there, including genetically engineered bacterial populations. Research emphasis and regulatory countenance has been predominantly on the first approach. Evaluation of operational utility of is continuing to identify conditions under which bioremediation can be used in an environmentally sound and effective manner, and to make recommendations to responders for the implementation of this technology.The issue of hydrocarbon toxicity has been examined in petroleum refinery and petrochemical workers for more than a decade, and experimentally in test animals for a much longer period. However, there has been little specific information available on the effects of oil spills on human health, neither for oil spill response workers nor for incidentally exposed individuals. More recently, as reviewed in an article on human health effects in this publication, some reports have been published of skin irritation and dermatitis from exposure of skin to oil during cleanup, as well as nausea from inhalation of volatile fractions. Although there are to date no epidemiological studies of exposure by oil spill workers to petroleum hydrocarbons, the matter is drawing increasing attention.One of the more important issues surrounding the choice and extent of application of oil spill countermeasures is knowledge about the ecological effectiveness of such response, that is, the balance point between continuation of clean up activities and letting the environment take care of its own eventual recovery. It is the last point which has driven much of the discussions and research associated with the concept of 'how clean is clean', or, how much cleanup is enough or too much. The results of such diverse research efforts are being used increasingly and successfully to link spilled oil chemistry to countermeasures practices and equipment. The advances are being integrated into more effective response management models and response command systems. In summary, applied chemical research and development has actively contributed to an enhancement in oil spill response capability. Nonetheless, it seems that the pace of oil spill research and countermeasures development is slowing. The decrease is at least temporally associated with a decline in the frequency and magnitude of oil spills in recent years. Spill statistics gathered by organisations such as the publishers of the Oil Spill Intelligence Report, show that world-wide oil spill incidence and volume have continued to decline since the time of the Exxon Valdez spill event (see the Oil Spill Intelligence Report publication "International Oil Spill Statistics: 1997", Cutter Information Corp.). It is probably not coincidental that the amount of funding available for oil spill research and development, from both government and private industry sources, has declined similarly. In that context, the following articles are more a statement of currently accepted knowledge and practice, rather than being a 'snapshot in time' of intense ongoing research activities. The articles serve to capture the applied chemistry knowledge and experience of practitioners in a complex field, application of which remains essential for the development of improved oil spill countermeasures, and their effective use in real spill situations.

A simple sugar-derived supramolecular gelator of 1,6-dicaprylate sorbitan ester was designed and prepared as new oil solidifier. The gelation tests revealed that the gelator can gel or phase-selectively gel fuel oils, edible oils and some organic solvents. And the SEM images showed the structure of 3D fiber network was formed in the process of gelation. What’s more, the rate of oil removal in water was 85% and the recovery rate of spilled oils reached up to 60.29%.

ABSTRACT Crude oil spilled in the sea is mixed with the sea water by the wind and waves resulting in increases in its water content and viscosity as time passes. We have constructed a small, transfer type circulating water channel of an elliptical cuit-track form. Using an attached circulating unit, together with a war tunnel, artificial waves are generated to enable simulation corresponding to the natural circumstances in the sea. The experiment disclosed the following results.Drastic changes in the properties (water content and viscosity) of the oil depend on the power of waves.Contrasting processes are observed between heavy and light crude oils during weathering.Heavy crude oils form a massive water-in-oil emulsion (mousse) with increases in both water content and viscosity.Light crude oils behave differently at summer sea temperatures,

ABSTRACT Electric utilities have been increasing their use of Group V fuel oils (known in the industry as low-API gravity fuel oils or LAPIO), because of their relatively low cost and high btu values. Group V fuel oils are defined as having an API gravity less than 10 at 60° F (thus a specific gravity ≤1.00 g/cm3). These oils have a wide range of densities and properties and thus cannot be characterized as a single product with a given set of properties and behavior. Group V fuel oils can float, be neutrally buoyant, sink, or all three, depending on their composition and the physical nature of the receiving waters (salinity, temperature, suspended sediment content). They can physically separate into fractions with different behavior. Three models are proposed for predicting the behavior of Group V fuel oil spills, based on observations at previous spills. If spilled directly into the water, heavier-than-water oil will form into drops and remain in suspension if there is any current. In no-current areas, sinking oil can accumulate on the bottom and be recovered. When mixed in the surf zone, the oil tends to pick up sand and sink, without ever stranding on shore. Special problems are associated with locating, containing, and recovering oil that is neutrally buoyant or on the bottom.

ABSTRACT SIMAP (Spill Impact Model Application Package) is Applied Science Associates’ spill impact model system. The system is designed to simulate the fates and effects of spilled oils and fuels, to allow for an evaluation of the effectiveness of spill response activities, and to evaluate the probabilities of trajectories and resulting impacts. The physical fates and biological effects models in SIMAP are based on those in the CERCLA type A model for natural resource damage assessments (NRDAs), documented in French et al. (1996a). SIMAP may be used for real-time spill simulation, contingency planning, and natural resource damage and ecological risk assessments. The physical fates and biological effects models in SIMAP and the NRDA type A model were validated using data from 27 oil spills. The success of a model simulation depends on both the algorithms and the accuracy of the input data. The results of the validation, described herein, verify the model algorithms. The most important input data in determining accuracy of results are winds, currents, and biological abundances of the most affected species. Thus the model system, when applied with accurate environmental and biological data inputs, can quantitatively and objectively estimate the impacts of oil spills into aquatic systems.

ABSTRACT At the request of the US EPA Oil Program Center, the National Exposure Research Laboratory's Ecosystems Research Division (ERD) in Athens is developing an oil spill model that focuses on fate and transport of oil components under various response scenarios. A database of prototype oils for use in models is necessary. This multiple component composition data, however, is not typically available because of complexity of oil composition and the impossibility of immediate characterization in the event of a spill. Thus the creation of a database containing both physical property and chemical composition data for a number of common oils at various weathering percentages is highly desirable. The data set must be based upon fractionation of the oils into groups of compounds with similar structures and properties and further must reflect the changes to the oil over the course of the spill. Since 1984, the Emergencies Science and Technology Division (ESTD) of Environment Canada (EC) has developed a database on various physical and chemical properties of crude oils and petroleum products. Through many years endeavour, the database now contains information of hundreds of oils from all over the world. In 2002, funded by the US EPA and EC, the ESTD and ERD completed the cooperative project “Development of a Composition Database for Selected Multicomponent Oils,” to characterize ten prototype crude oils and refined petroleum products. The present work, Oil Composition and Property Database for Oil Spill Modeling, is a logical extension of the 2002 project. Nine new crude oils in common use and with potential to be spilled in the US waters were selected for inclusion in the model database. Comprehensive physical property measurement and chemical composition characterization have been performed for these oils at four weathered stages of each oil. This project provides the most complete and comprehensive database for the selected oils to date. The new composition data has been integrated into the existing US EPA and EC oil properties database. The results are made available to the public on the world wide web.

ABSTRACT High resolution gas chromatography (GC) and gas chromatography in conjunction with mass spectrometry (GCMS) were used as fingerprinting techniques in this study to link oil spilled from the New Carissa to oil taken from oil impacted locations. Analyses included normal and isoprenoid alkanes, hopanes, and steranes, as well as a range of polynuclear aromatic hydrocarbons (PAHS). The oil spilled from the New Carissa was initially thought to be limited to bunker oils. Therefore, chromatograms of these samples and selected ion monitoring (SIM) chromatograms of the components and their combinations were compared, and obvious mismatches were rejected. Initial comparisons seemed simple; however, as with the spill response itself, factors that most often are insignificant began to affect the chemical analyses. Complications and technical challenges using conventional fingerprinting methods arose for several reasons. Likely reasons are (1) the spilled oil weathered on continued exposure to environmental conditions; (2) burning could cause changes to the chemical fingerprint; and (3) potential inhomogeneity of the spill because of multiple fuel sources in five fuel tanks at the bottom of the vessel. The PAH fingerprint had limited resistance to weathering. Therefore, the hopane fingerprint was selected for its resistance to weathering and potential screening power. Preburn and postburn New Carissa oil was characterized using principal component analysis (PCA) to determine if new and seemingly unrelated tarballs could be derived from the New Carissa spill. Response personnel will benefit from the lessons learned about potential complications of oil identification and subsequent determination of origin.

ABSTRACT Forensic approaches for differentiating spilled oils, tar balls, and oil-contaminated sediments by source can be enhanced by converting qualitative GC/MS data to quantitative values and applying statistical data analyses. Such techniques reduce the potential for chemist bias and fatigue that can result in false-positive and false-negative determinations. The suite of indexes used by our laboratory are highly discriminating, resistant to oil weathering and biodegradation, and are not subject to most day-to-day laboratory variances. We have applied the term “self-normalizing fingerprint indexes” (SFIs) to label such parameters or ratios. The SFI approach has been demonstrated to reduce investigator bias and highlight subtle differences in actual spill samples and baseline monitoring studies that might have been missed by standard qualitative approaches to source-fingerprinting. This approach represents another step in the development of legally defensible methods of oil spill response.

Extensive asphalt pavements have persisted along >25 km (km) of shoreline on Abu Ali Island, on the Arabian (Persian) Gulf coast of Saudi Arabia, reportedly stranding as a result of the 1983–1985 Nowruz oil spills. A study was conducted in October 2020 to support development of a remediation plan. Cross-shore transects were surveyed at 100 m intervals and 1434 shovel test pits were dug to determine oil type, thickness, and depth of burial. Oiling of any description was observed at 76% of the pits. Using 15 diagnostic biomarker ratios, only 5 of the 94 oiled samples from Abu Ali Island in 2020 likely contain other oils. Data on historical spills were identified from the literature. Based on chemical biomarker data for potential source oils in the northern Arabian (Persian) Gulf, the diagnostic ratio for the biomarkers 18a-22,29,30-Trisnorneohopane (Ts) and 17a(H)-22,29,30-Trisnorhopane (Tm) for the 94 samples only matched one Iraq crude oil. No large individual spills of Iraq crude oil were identified in the literature or spill databases, although releases of both Kuwait and Iraq crudes were reported for the 1991 Gulf War oil spills. However, oil residues from Abu Ali did not match most prior samples of Saudi shoreline oiling from the Gulf War oil spills, which largely consisted of spilled Kuwait crude. Though we cannot definitely conclude that the majority of the residual oil on Abu Ali Island delineated during the 2020 survey is oil from the Nowruz oil spills, because there is no source oil from these spills, we use a weight of evidence approach to say that it is highly likely that the majority of the residual oiling is from the Nowruz spills.

ABSTRACT Chemical dispersants are used in oil spill response operations to enhance the dispersion of oil slicks at sea as small oil droplets in the water column. To assess the impacts of dispersant usage on oil spills, US EPA is developing a simulation model called the EPA Research Object- Oriented Oil Spill (ER03S) model (http://www.epa.gov/athens/research/projects/erosl). Due to the complexity of chemical and physical interactions between spilled oils, dispersants and the sea, an empirical approach to the interaction between the dispersant and oil slick may provide a useful or practical approach for including dispersants in a model. The main objective of this research was to create a set of empirical data on three oils and two dispersants that has the potential for use as an input to the ERO3S model. These data are intended to give an indication of the amount of dispersal of these oils under certain environmental conditions. Recently, the US EPA developed an improved dispersant testing protocol, called the baffled flask test (BFT) which was a refinement of the swirling flask test. Use of this protocol was the basis of the experiments conducted in this study. The variations in the effectiveness of dispersants caused by changes in oil composition, dispersant type, and the environmentally related variables of temperature, oil weathering, and rotational speed of the BFT were studied. The three oils that were tested were South Louisiana Crude Oil, Alaska North Slope Crude, and Number 2 fuel oil. Two dispersants that scored effectiveness above 85% by the BFT were selected for this study. A factorial experimental design was conducted for each of the three oils for four factors: volatilization, dispersant type, temperature and flask speed. Each of the four factors were studied at three levels except for the dispersant factor where only two dispersants were considered. Statistical analysis of the experimental data were performed separately for the three oils. Analysis of variance was conducted to determine which factors, or set of factors, were related to the percent effectiveness. Empirical relationships between the amount of oil dispersed and the variables studied were developed.

ABSTRACT Aggregation between suspended sediment grains and oil droplets, which leads to the formation of agglomerates commonly referred to as Oil-Mineral Aggregates (OMA), is widely acknowledged as a natural process that enhances dispersion of spilled oil in aquatic environments. A comprehensive numerical approach is developed to predict the contribution of OMA formation to the dispersal of spilled oil. The model comprises four modules to calculate maximum size of oil droplets, to predict formation of oil droplets from a slick, to predict formation of sediment floc, and to calculate density of oil-sediment flocs. The inputs of the model are environmental conditions, oil properties and concentration and grain-size distribution of suspended sediments. Sensitivity analysis performed using five crude oils covering a range of viscosities from 8 10−3 to 68 10−3 kg/ms, a kinetic energy dissipation rate from 10−3 to 102 m2/s3, a sediment grain size of 3 μm and a sediment concentration of 250 mg/l showed that formation of OMA is strongly dependent on the oil-water interfacial tension and the kinetic energy dissipation rate. Under breaking wave conditions, the contribution of OMA formation to the dispersal of spilled oil varies between 31 and 97 % depending on characteristics of the individual test oils, in particular oil-water interfacial tension. Results show also that OMA formation is enhanced when the Weber number approaches a value of 0.05.

ABSTRACT Faced with the latest experiences on Brazilian oil spill incidents, Petrobras has been trying to overcome many challenges in environmental management and operational safety, aiming to prevent environmental risks. This paper presents the oil characterizations and monitoring studies in affected ecosystems such as the hot spots on soils affected by the Iguassu River oil spill (occurred in July 2000, due to a pipeline rupture in the scraper area of REPAR, a Petrobras refinery located in the state of Parana), by the Vessel Vergina II oil spill in São Sebastião channel (located in the state of São Paulo, occurred in November 2000) and lastly, the Guanabara Bay oil spill (a pipeline rupture that occurred in January 2000, due to a pipeline rupture between oil terminal and REDUC, a Petrobras refinery located in the state of Rio de Janeiro). Chemical analysis were performed in different sample matrixes including many parameters such as total petroleum hydrocarbons (TPH), aliphatic compounds (n-alkanes), unresolved complex mixtures (UCM), benzene, toluene, ethylbenzene and xylenes (BTEX), polycyclic aromatic hydrocarbons (PAH), terpanes and steranes, that are the parameters usually monitored after a spill oil. Visual inspections were also performed mainly in Guanabara Bay in order to identify the affected ecosystems by the spilled oil and to plot maps of classified regions based on the level of visual oil contamination. The acute toxicity was evaluated in water soluble fraction (WSF) of the spilled oils using ecotoxicological tests.

ABSTRACT Many previous studies using laboratory test methods have shown that the ability to disperse spilled oils depends on several factors including: spilled oil properties (and how these change with oil weathering), the mixing energy, and the dispersant-to-oil ratio (DOR). There appears to be a ‘limiting oil viscosity’ value that, when exceeded, causes a sharp reduction in the effectiveness of a dispersant. The results obtained in laboratory tests are relative and not absolute, and it has therefore proved very difficult to correlate dispersant effectiveness results from these laboratory tests with dispersant performance at sea. A series of small-scale dispersant tests were conducted at sea in the English Channel in June 2003. Several small test slicks of residual fuel oils of different viscosity grades were laid on the sea and immediately sprayed with different dispersants at different DORs. Observers used a simple ranking system to visually assess the degree of dispersion that occurred when a cresting wave passed through an area of the dispersant-treated oil. Collation of the results showed that there were obvious and consistent differences in the degree of effectiveness observed with different combinations of oil viscosity, dispersant and treatment rate.

Floating vessel-type oil collecting devices based on sorbent materials present potential solutions to oil spill cleanup that require a massive amount of sorbent material and manual labor. Additionally, continuous oil extraction from these devices presents opportunities for highly energy-efficient oil skimmers that use gravity as the oil/water separation mechanism. Herein, a sorbent-based oil skimmer (SOS) is developed with a novel funnel-shaped sorbent and vessel design for efficient and continuous extraction of various oils from the water surface. A carbon black (CB) embedded polydimethylsiloxane (PDMS) sponge material is characterized and used as the sorbent in the SOS. The nanocomposite sponge formulation is optimized for high reusability, hydrophobicity, and rapid oil absorption. Joule heating functionality of the sponge is also explored to rapidly absorb highly viscous oils that are a significant challenge for oil spill cleanup. The optimized sponge material with the highest porosity and 15 wt% CB loading is tested in the SOS for large-scale oil spill extraction tests and shows effective cleaning of oil spilled on the water surface. The SOS demonstrates a high maximum extraction rate of 200 mL/min for gasoline and maintains a high extraction rate performance upon reuse when the sponge funnel is cleaned and dried.

As observed in several recent cases (e.g., DBL-152, Enbridge-Kalamazoo), under certain circumstances, spilled oil can sink to the bottom of a water body. Once on the bottom, the oil can move or even remobilize into the water column. The critical shear stress (CSS) is used to accurately predict the movement of sunken oil along and off the bottom. Unfortunately, shear stress has only been measured for one sunken oil (Hibernian Crude API = 34). The Coastal Response Research Center (CRRC) at the University of New Hampshire (UNH) has an annular flume equipped with high-definition cameras and an acoustic velocimeter that can be used to estimate CSS by measuring the instantaneous, three-dimensional water current velocities at which sunken oils move and erode as visible oil droplets. The results reported are for an Alberta bitumen, tested at temperatures between 5° and 28°C in freshwater.

ABSTRACT The increased demand and marine transportation of low-API oil (LAPIO), a group V fuel oil, has posed new problems for pollution responders. Group V oils have a specific gravity greater than 1 or an API gravity less than 10, and when spilled into the marine environment do not remain on the surface of the water. On October 11, 1995, more than 4600 barrels of LAPIO were discharged into the lower Mississippi River at mile 126, Above Head of Passes. Through creative engineering techniques nearly 50% of the oil was recovered from the bottom of the river. This paper covers the summary of events, the problems encountered, and the federal on-scene coordinator's recommendations for future group V oil spill response.

The formation of sunken oils is mainly dominated by the interaction between spilled oils and sediments. Due to their patchiness and invisibility, cleaning operations become difficult. As a result, sunken oils may cause long-term and significant damage to marine benthonic organisms. In the present study, a bench experiment was designed and conducted to investigate the quantitative distribution of polycyclic aromatic hydrocarbons (PAHs) in sunken oils in the presence of chemical dispersant and sediment. The oil sinking efficiency (OSE) of 16 priority total PAHs in the sediment phase was analyzed with different dosages of dispersant. The results showed that the synergistic effect of chemical dispersant and sediment promoted the formation of sunken oils, and the content of PAHs partitioned in the sunken oils increased with the increase of dispersant-to-oil ratios (DORs). Furthermore, with the addition of chemical dispersant, due to the solubility and hydrophobicity of individual PAHs, the high molecular weight (HMW) PAHs with 4–6 rings tended to partition to sediment compared with low molecular weight (LMW) PAHs with 2–3 rings. The synergistic effect of chemical dispersant and sediment could enhance the OSE of HMW PAHs in sunken oils, which might subsequently cause certain risks for marine benthonic organisms.

Abstract 2017-182 The dispersal and weathering processes of crude and fuel oils have been studied for decades and significant scientific information has been published. However, the fate and behaviour of spilled nonconventional crude oil such as diluted bitumen products are less well understood. There is concern that a spill of the oil sands diluted bitumen may come into contact with marine shorelines as it is transported throughout Canada. There is uncertainty related to the fate of spilled diluted bitumen and potential interactions with shorelines. A Shoreline Oil Spill Research and Development Program was undertaken by Environment and Climate Change Canada (ECCC). In 2013, a 3-year study was initiated and focused on the marine shorelines of northern British Columbia (BC). Four field campaigns were conducted along the entire length of coast throughout the Douglas and Granville channels as well as Banks and Haida Gwaii islands. The field campaigns were used as an opportunity to develop and employ a new approach to collect and compile an extensive pre-spill baseline dataset. Data included an aerial survey with high definition video and a ground survey of representative shorelines where samples were collected and analyzed for petroleum hydrocarbons, carboxylic acid, pesticides, heavy metals, calcium carbonate and sediment grain size. Baseline levels of hydrocarbons in the sediment of the study areas were estimated based on the analysis of total petroleum hydrocarbons (TPH), n-alkanes ranging from n-C9 to n-C40, petroleum related biomarkers such as terpanes and steranes, polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues (APAHs).

ABSTRACT 2017-076 In this paper, we discuss a new class of i-PetroGel oil-superabsorbent technology that has shown a potential solution to the oil spill recovery and cleanup in arctic environments, based on the laboratory tests at Penn State and an open tank test at Ohmsett. This i-PetroGel material is formed by polyolefin polymers that are petroleum downstream products with similar oleophilic and hydrophobic properties of oil molecules. Apart from many oil sorbents based on adsorption, i-PetroGel absorbs oil by absorption (similar to Hydrogel absorbing aqueous solutions) and swells to a large volume. During Ohmsett testing, i-PetroGel flakes spread on top of the affected area showed effective transformation of Alaska North Slope (ANS) oil into a floating gel on the seawater surface, which was effectively recovered by an oleophilic drum skimmer and pumped to a storage tank. The recovered ANS oil-swelled adducts, containing <0.1 wt% water, exhibit similar distillation characteristics as the original ANS oil. Overall, this i-PetroGel technology could potentially provide a comprehensive solution for combating oil spills, with the goal to dramatically reduce the environmental impacts from oil spills and help recover one of the most precious natural resources. i-PetroGel exhibits a combination of desirable properties. ✓ High oil absorption capacity about 35–40 times by weight at 3 and 25 °C. ✓ Suitable to a broad range of hydrocarbons, including complex crude oils, refined oil products (gasolines, diesels, heating oils, etc.), and solvents (toluene, benzene, etc.). ✓ Fast kinetics in capturing the spilled oil. ✓ No detectable water absorption in i-PetroGel. ✓ The resulting oil/i-PetroGel adducts floating on water surface are recovered by skimmer. ✓ The recovered oil/i-Petrogel adducts can be refined as crude oil through standard refining processes. ✓ Cost effective. ✓ No secondary pollution.

ABSTRACT Oil spills in nearshore environments may eventually move into sensitive coastal habitats such as coastal marshes and impact marsh organisms. Application of dispersants to spilled oil in nearshore environments before the oil drifts into marshes was simulated, and the toxicity, impact and effectiveness of dispersants were investigated. The tolerance of the marsh plant Sagittaria lancifolia to the recently marketed dispersant JD-2000 was about 20 to 80 times higher than that of the standard test-organisms Menidia beryllina and Mysidopsis bahia, respectively. The LC50 of the dispersant JD-2000 for Sagittaria lancifolia was greater than 8000 ppm. Furthermore, the application of the dispersant JD-2000 significantly relieved the adverse effects of crude, diesel and No. 2 fuel oil on marsh vegetation. Upon contact with plant shoots on the rising tide, the un-dispersed oils detrimentally impacted the marsh plants Spartina alterniflora and Sagittaria lancifolia. Mortality rates significantly increased even at a 150-ppm oil dosage. The 750-ppm No. 2 fuel oil without the dispersant application resulted in more than 90 % mortality for Spartina alterniflora in 3 weeks. In contrast, the oils chemically dispersed with JD-2000, regardless of oil type and oil concentration, did not significantly affect the marsh plants compared to the no-oil control. Therefore, the dispersant application greatly reduced oil impact on marsh vegetation, indicating the potential for using dispersants as alternative countermeasures to protect sensitive coastal habitats during nearshore oil spills. The use of dispersants in oil spill cleanup has attracted great attention since the Exxon Valdez oil spill in 1989. However, dispersants have been a controversial oil spill response technique because of disagreement about their effectiveness and concerns of their toxicity since their introduction during the Torrey Canyon oil spill in 1967 (Cunningham et al. 1991; Venosa et al. 1999). Dispersant use has been recommended for oil slicks in the sea before coastal habitats are reached, though minimal guidelines have been outlined (Page et al. 2000). Therefore, the effects of dispersants, including Corexit 9527 and Corexit 9500 listed in the National Contingency Plan (EPA, 2001), have mainly been focused on marine organisms, such as fishes, shrimps, and the larvae of fishes, crabs, and corals (Singer et al. 1994; Rhoton et al. 1999; Gulec and Holdway 2000; Epstein et al. 2000; Wolfe et al. 2001). Most of these studies on marine organisms were acute toxicity tests. However, decisions to use oil spill response chemicals should not be based solely on aquatic toxicity (George and Clark 2000). A handful of studies have been conducted on the effects of dispersants on plants from salt to freshwater marshes. Some studies indicated that dispersants, such as BP 1100WD (Baker et al. 1984), Corexit 9527 (Lane et al. 1987) and BP Enersperse 1037 (Little and Scales 1987), were ineffective in cleaning the oiled salt marshes, and had greater detrimental impact on salt marsh plants, such as Spartina anglica, Salicornia spp, Spartina alterniflora and Aster spp than oils without applying dispersants. In contrast, other studies (Smith et al. 1984, DeLaune et al. 1984) demonstrated that dispersants applied to Louisiana crude oil contaminated Spartina alterniflora had short term benefits to plant photosynthesis although it did not have long-term effects on plant biomass. Dispersants used today are more effective and less toxic (NCR 1989). For example, the dispersant JD-2000 recently marketed by the GlobeMark Resources Inc. in 2001 is especially effective for south Louisiana crude oil (EPA 2001) for both salt and fresh water environments. It is a high performance, biodegradable oil spill dispersants listed in the NCP (EPA 2001). However, little information is available on the toxicity and effects of dispersants on marsh habitats and the strategy of dispersant-use in the nearshore to protect sensitive coastal habitats. The overall goal of the study was to determine the potential use of dispersants as oil spill countermeasures in nearshore environments in which spilled oil may eventually move into coastal marshes with tide and wind, and impact sensitive wetland habitats. The specific objectives of the study were (1) to evaluate the toxicity of dispersants on coastal marsh plants by determining the doseresponse of plants to dispersants, and (2) to evaluate effects and effectiveness of dispersants on protecting coastal marsh habitats from impact of different oils (crude, diesel, and fuel oil).

ABSTRACT The Enbridge Line 6B pipeline release of diluted bitumen into the Kalamazoo River downstream of Marshall, MI in July 2010 is one of the largest freshwater oil spills in North American history. The unprecedented scale of impact and massive quantity of oil released required the development and implementation of new approaches for detection and recovery. At the onset of cleanup, conventional recovery techniques were employed for the initially floating oil and were successful. However, volatilization of the lighter diluent, along with mixing of the oil with sediment during flooded, turbulent river conditions caused the oil to sink and collect in natural deposition areas in the river. For more than three years after the spill, recovery of submerged oil has remained the predominant operational focus of the response. The recovery complexities for submerged oil mixed with sediment in depositional areas and long-term oil sheening along approximately 38 miles of the Kalamazoo River led to the development of a multiple-lines-of-evidence approach comprising six major components: geomorphic mapping, field assessments of submerged oil (poling), systematic tracking and mapping of oil sheen, hydrodynamic and sediment transport modeling, forensic oil chemistry, and net environmental benefit analysis. The Federal On-Scene Coordinator (FOSC) considered this information in determining the appropriate course of action for each impacted segment of the river. New sources of heavy crude oils like diluted bitumen and increasing transportation of those oils require changes in the way emergency personnel respond to oil spills in the Great Lakes and other freshwater ecosystems. Strategies to recover heavy oils must consider that the oils may suspend or sink in the water column, mix with fine-grained sediment, and accumulate in depositional areas. Early understanding of the potential fate and behavior of diluted bitumen spills when combined with timely, strong conventional recovery methods can significantly influence response success.

This paper presents an integrated scientific and engineering strategy to improve and bring planning and decision-making for marine oil spill response to a higher level of knowledge. The most efficient, environmentally preferred, and cost effective spill response is dependent on the following factors: chemistry of the spilled product, quantity, location, response time, environmental conditions, and effectiveness of available response technologies at various degrees of oil weathering.Time windows is a highly targeted process, in which the selection of response technologies will be more efficient, cost effective, technically correct, and environmentally sensitive and appropriate. The strategy integrates dynamic oil weathering data and performance effectiveness data for oil spill response technologies derived from laboratory, mesoscale, and experimental field studies. Performance data has been developed from a wide range of viscosities of different weathering stages of transported oils into a dynamic oil weathering database to identify and estimate time periods, called "technology windows-of-opportunity." In these windows, specific response methods, technologies, equipment, or products are more effective during clean-up operations for specific oils. The data bases represent the state of the art for response technologies and research in oil spill response.The strategy provides a standard foundation for rapid and cost effective oil spill response decision-making, and is intended for use by local, state, federal agencies, response planners, clean up organizations (responders), insurance companies, tanker owners, and transporters. It provides policy, planners and decision-makers with a scientifically based and documented "tool" in oil spill response that has not been available before.

ABSTRACT The American Petroleum Institute Spill Response and Effects Task Force has developed guidelines (a “model plan”) for use of dispersants on spilled oil. This model plan is consistent with subpart H of the National Contingency Plan and provides the information needed to implement subpart H. The model plan addresses the questions of where, when, why, and how dispersants should be used and what materials should be used. The components of the model plan are the following:Detailed descriptions of most of the currently used methods for making dispersant use decisionsA dispersant use information form (Federal Region VI format)Discussion of the technical basis for dispersant use decision makingTabulations of properties (specific gravity, viscosity, pour point, and sulfur content) of oils transported through or produced in the area of interest, including an indication of relative dispersibility of each of these productsInventories of dispersants and application equipmentA quality assurance/quality control planLiterature on dispersant application techniques. The purpose of developing this model plan is to provide a format that may be used to establish consistent regional and local dispersant use plans throughout the country.

When oil is spilled into the marine environment, it may be found on the water's surface, in the water column, in the sediment, or on the shoreline. When delineating the extent of contamination, it is important to be able to differentiate the spilled oil from other components that may appear to be oil. There are established methods for detecting oil-in-water, such as fluorometry, that allow in situ measurements to be made. In this study, we investigate both established methods and potential technological advancements that could provide a means for a site investigator to gather meaningful on-site information regarding the presence of oil. The primary focus will be usefulness to a shoreline application, but application to other types of samples is addressed. The degree to which an oil could be identified using these portable methods, such as the ability to differentiate petrogenic from biogenic oils, is also discussed. Method comparisons are discussed, with relevance to portability, selectivity, relative cost, and ability to process multiple samples.

ABSTRACT When spilled at sea, many oils are known to form emulsions. These emulsions are often of high-water content and viscosity, poorly dispersible, hard to recover and pump, and likely to remain as a persistent pollutant that may come ashore. To avoid these difficulties, demulsifiers have been used, either to inhibit emulsion formation or to break emulsions that have already been created. CEDRE (Centre de Documentation de Recherche et d'Experimentations sur les Pollutions Accidentelles des Eaux) has studied the efficiency of several demulsifiers on the rate of emulsion formation and on the dispersability of emulsified oils of different types. This study was conducted in three stages. First, a study of the rate and extent of emulsification was conducted in the laboratory. Second, the effect of demulsifiers was studied in floating mesocosms placed in a harbor. The demulsifiers did not succeed in totally preventing emulsion formation, but they inhibited the degree of emulsification of the oils for some time. Third, the dispersability of weathered oils was studied in laboratory using the IFP and WSL test methods and then in the Polludrome, where the effects of different treatment strategies combining demulsifiers and dispersants applications were assessed.