Dispersants Bibliography

Abstract
This article reports on an alliance that would combine aerial dispersant with aerial surveillance in a rapid response counter to oil spills in the North Sea. Later improvements would be smaller, faster aircraft for improving response time

Abstract
For each of the following methods which employ chemicals to clean up oil spills in ocean, lake, and river waters, the process is explained and available products are described--sorbants, dispersants, oxidation and biodegradation, and jelling and polymerization. The Federal Water Quality Administration policy on the use of chemicals to treat floating oils is given

Abstract
The State of São Paulo has established a program for research on and for licensing of chemical dispersants. The basic factors adopted for evaluation and approval of these products were their composition, efficiency (or effectiveness) and toxicity. Various methods for evaluation have been tested; the Warren Spring method was chosen due to its greater repeatability, rapidity, and lower cost. The U.S. EPA toxicity evaluation procedure with Artemia nauplii was chosen for licensing the products, due to its relative simplicity and repeatability. (A new assay procedure, intended to replace the Artemia test, was initiated with a regional shrimp and is progressing as a research program.) A linked composition/efficiency/toxicity licensing procedure has been developed

Abstract
The effects of petroleum biodegradation of several oil herders, dispersants and commercial bacterial inocula were tested. The oil herders and dispersants significantly increased the rate of mineralization but not the extent of petroleum biodegradation. The beneficial effect is apparently due to the increased surface of oil droplets and an absence of toxicity to oil degrading microorganisms at the recommended concentrations. The two commercial bacterial inocula tested failed to improve either the rate or the extent of oil biodegradation when tested in natural seawater. In sterile seawater, these inocula showed inferior performance compared to the natural microflora of seawater, and were judged to be ineffective for marine applications. Data on the safety and effectiveness of available oil pollution control products are basic to their correct use. While numerous studies have been conducted on the toxicity of such products to vertebrates and invertebrates, little is known about their effects on the indigenous microflora of the sea. Since microbial degradation is the major natural process for the ultimate destruction of polluting oil, it is essential that this process not be interfered. The recommended concentrations of two oil herders, six dispersants and two bacterial inocula were tested for their effects on the biodegradation of Sweden crude oil in freshly collected seawater samples

Abstract
Recycled poly (ethylene terephthalate), PET, can be modified to produce nonionic surfactants. Recycling of PET waste was carried out in presence of different weight ratios of diethanolamine and triethanolamine and manganese acetate as catalyst. The molecular weights of the prepared oligomers were calculated from hydroxyl number and determined from GPC measurements. The produced oligomers were reacted with polyethylene glycol, PEG, which have different molecular weights 400, 1000 and 4000. Interfacial tension and the effectiveness in oil dispersion of the synthesized surfactants were reported. It was found that, the maximum efficiency of oil spill dispersants was reached to maximum when the surfactant molecules ended with two PEG 1000 moities

Abstract
Finasol OSR-5 and OSR-12 were chosen, along with Statfjord A + B crude oil, to determine exposure effects of oil, dispersant, and combinations on a species of amphipod. Reduced mortality in amphipods resulted when Finasol OSR-5 was added to the crude oil, compared to exposure to the water soluble fraction and water emulsion of crude oil alone

Abstract
Authors suggest a methodology for using ecological risk assessment procedures in the oil spill response planning process, which would improve the ability to evaluate response options, including the use of dispersants

Abstract
The use of dispersants in oil spill response in the United States remains a controversial environmental topic. At the center of this controversy is a lack of confidence in the available data to evaluate the effects of dispersants on “local” biota. The main reasons that many of the attempts around the country to resolve concerns over dispersant use have been unsuccessful are that they have either 1.) failed to focus on the true issues of concern, 2.) collected laboratory (and sometimes field) data which cannot be effectively applied in decision-making, or 3.) failed to effectively communicate information to the participants in the decision process. These issues can be addressed by a research program intentionally designed to examine issues in an ecosystem context and which focuses on information dissemination and communication, which are the central themes of the Marine Spill Response Corporation (MSRC) initiative. The MSRC environmental program contains four elements: improved use and synthesis of existing information, improved methods for laboratory toxicity evaluations and interpretation, development of a realistic mesocosm testing program, and field experiments to correlate laboratory and mesocosm data to real world situations. This paper describes the rationale for the program and the progress made over the first two and one-half years

Abstract
In the United States, pre-approval for dispersant use exists only in conservatively defined circumstances of water depth and/or distance off shore. Historical records suggest that most opportunities for dispersant use will occur closer to shore and in shallow water than defined in existing pre-approval areas. The issue is to determine when it is appropriate to relax these standards in order to protect sensitive near-shore habitats, despite the potential for increased ecological effects in the water column. This paper reviews selected data in the context of Ecological Risk Assessment (ERA) protocols. In some cases onshore impacts are clearly decreased by dispersant use without adversely affecting the water column. This is especially true for small or moderate-sized spills, often not viewed as a high priority for dispersant use. In other cases, however, trade-off decisions must be made, and when the ERA approach is properly integrated into oil spill response process, it can improve the likelihood of proper use of dispersants, and assist in the identification of appropriate dispersant response capabilities

Abstract
A mesocosm experiment on nearshore dispersant use compared results of water column and shoreline exposure to crude oil and dispersed oil. Fate and ecological effects were determined in 10-day experiments. The use of multiple tanks housed at the Coastal Oilspill Simulation System Facility in Corpus Christi, Texas, allowed for simultaneous tests and provided the opportunity for replicate treatments and untreated controls during testing

Abstract
This project defines circumstances where a dispersant demonstration might be considered for an estuarine oil spill in Texas. In seeking approval for a spill of opportunity demonstration project, we developed criteria defining a viable dispersant response for consideration by the Region VI Regional Response Team. This paper presents the criteria and their rationale developed for Galveston Bay and Corpus Christi Bay, along with the results of recent training exercises. The criteria define the size and general location of an oil spill that might be considered appropriate for a trial dispersant application, and implementation of response and monitoring within a 2-hour window from notification. They are based on descriptions and characterizations of the habitats and species at risk in coastal areas, concentration and duration of dispersed oil plumes that might be generation in a response, potential impacts of these exposures, and the environmental trade-off between implementing mechanical response and a dispersant response. Because the dilution potential is constrained in shallow water environments, spill size has significant impact on the magnitude and duration of potential exposure regimes for water column organisms. Spills of 250 bbls or less pose minimal concern for water column communities with potential net benefit to other coastal resources. The trade-offs were not so obvious for larger spills. The exposure regimes and potential impacts for water-column organisms that would be maximally exposed during a dispersant operation were compared to the exposures and potential impacts for organisms and habitats exposed to floating oil and oil stranded on shorelines, at levels that could result during a mechanical recovery operation. These potential impacts are compared on a spatial and temporal basis, and with consideration for potential rates of recovery

Abstract
This paper summarizes the results of two cooperative ecological risk assessments (ERAs) that examined the potential environmental consequences of oil spill scenarios, two in the vicinity of San Francisco Bay, California and one in Galveston Bay, Texas. The goal of the evaluation was to identify the optimum mix of response options for reducing injury to the environment. For these specific scenarios, the participants concluded that only dispersant use, assuming high effectiveness, had the potential to significantly reduce environmental impact when compared to natural recovery. While water-column effects increased with dispersant use, they were not long-term and judged to be of less ecological significance than shoreline or water-surface impacts. Aside from dispersant use, only shoreline cleanup was effective in clearly mitigating impacts, and obviously would not prevent the immediate consequences of the spills. The optimum response was viewed as involving some combination of the various response options. There were some issues with data adequacy in both locations, but both groups felt the information was adequate for the analysis. In both ERAs, participants emphasized that the conclusions were scenario specific, and that additional analyses would be necessary before any significant generalizations could be made

Abstract
The Marine Spill Response Corporation (MSRC) and the American Petroleum Institute (API) recently completed a multiyear research program on dispersants and dispersed oil consisting of four elements: information synthesis and dissemination, improved laboratory methods for toxicity evaluation, mesocosm testing, and field experiments. These research efforts contributed to the recent changes in the way dispersants are viewed in the United States. When combined with other research findings from the last 10 years, this information, now available to response planners, greatly improved and contributed to a growing interest in the use of dispersants, including the potential for the extension of preauthorization areas. The primary objectives of this paper are to summarize the objectives of the program, highlight major findings, and identify the sources where the results can be examined in detail

Abstract
The toxic effects of crude oil, the dispersant, Corexit 7664, and mixtures of these on the respiration and mortality of two species of bivalve have been examined. A light Arabian crude is most toxic to one, Corexit is most toxic to the other. The susceptibility to oil of the mussel Brachidontes is also reflected in a significant depression of respiration rate at sub-lethal concentrations

Abstract
In November 1984, non-treated Prudhoe Bay crude oil and dispersed Prudhoe Bay crude oil were intentionally released into two separate sites, representative of nearshore mangrove, seagrass, and coral ecosystems, as part of the Tropical Oil Pollution Investigations in Coastal Systems (TROPICS) field study in Bahia de Almirante, Panama. Data on the relative effects of non-treated crude oil and dispersed crude oil on these ecosystems (compared to a reference site) were acquired analyzed over various periods (30 days, 3 months, and 2.6, 10, 17, 18, and 20 years). in the short term, the oil caused mortality to invertebrate fauna, seagrass beds, and corals at both sites. At the non-treated crude oil site, there was also significant mortality to the mangrove forest. Twenty-year observations on mangrove substrate core samples reveal the continued presence of oil and diminished mangrove repopulation, as well as substrate erosion, at the non-treated crude oil site. No oil was detected and no long-term impacts were observed at the dispersed crude oil and reference sites. These results provide baseline scientific data for developing a Net Environmental Benefit Analysis (NEBA) of dispersant use in nearshore tropical systems. This paper is a review of TROPICS data and its application to NEBA preparation. Data and NEBA from the 20-year TROPICS study clearly show that the use of dispersant in the nearshore environment is a sound strategy for both minimizing environmental damage to tropical ecosystems and for providing the best opportunity for recovery and repopulation in this environment. Results of this work should be applicable to similar tropical ecosystems

Abstract
Turtle grass beds, a valuable natural resource, are diminishing throughout the tropics because of damage from dredging, boats, and other factors. The toxicity of chemical dispersants and crude oil to turtle grass was determined in the laboratory to assess the potential for damage from spills occurring in the field. Studies of water-soluble fractions (WSF) of crude oil in static bioassays showed that a chemical dispersant (Corexit® 9527) increased the amount of total oil in water more than 50-fold. The toxicity of chemically dispersed oil was assessed by conventional (96-h 50% lethal concentration) methods in static systems, and the results were compared with toxicity measurements where the system was flushed after 12 h. the 12-h single dose systems simulated certain active natural systems by the incorporation of dilution by tides and by using shorter exposure times. The rationale was verified by work with oil spills in the tropics. Using actual total hydrocarbon concentration for crude oil, dispersed oil, and dispersants alone allowed a comparison of their toxicities. Prudhoe Bay crude WSF was more toxic than dispersed oil or dispersant alone, possible because of the large component of benzene, toluene, and C-2 benzene. The percentage of green (chlorophyllous) leaves was useful as evidence of toxicity. The importance of anatomical features such as the recessed meristem and abundant leaf sheaths in protecting the growing region from waterborne pollutants was evident

Abstract
A method is described for site-specific advanced planning for dispersant use. The method was designed to be an integral part of a spill response plan for a portion of the California coast and to provide site-specific information to the On-Scene Coordinator (OSC) regarding the use or nonuse of dispersants. The development of the dispersant use plan follows the findings of the American Petroleum Institute (API), the American Society for Testing and Materials (ASTM), and a special task force of government and industry representatives formed to develop and critique the plan for the California study area. The dispersant use plan considers several physical factors, including the type, amount, and trajectory of spilled oil, and ecological factors, such as species and habitat sensitivity and seasonality. Four categories of recommendations are given in maps: 1. Dispersant use recommended to protect sensitive intertidal habitats or species; 2. Dispersant use unrestricted; 3. Dispersant use with some restrictions; 4. Dispersant use not recommended. although the plan was originally designed for application in the central and southern California area, the method may be applied elsewhere with some modification

Abstract
The biodegradation experiment, the TOD analysis and the element analysis for dispersant, Bunker-A oil and Bunker-B oil were conducted to study the biodegradation characteristics of a mixture of Bunker-A oil with dispersant and a mixture of Bunker-B oil with dispersant in the seawater. The results of biodegradation experiment showed 1 mg of dispersant to be equivalent to 0.26 mg of BOD5 and to 0.60 mg of BOD20 in the natural seawater. The results of TOD analysis showed each 1 mg of dispersant, Bunker-A oil and Bunker-B oil to be equivalent to 2.37 mg, 2.94 mg and 2.74 mg of TOD, respectively. The results of element analysis showed carbon, hydrogen, nitrogen and phosphorus contents of dispersant to be 82.1%, 13.8%, 1.8% and 2.2%, respectively. Carbon and hydrogen contents of Bunker-A oil were found to be 73.3% and 13.5%, respectively, and carbon, hydrogen and nitrogen contents of Bunker-B oil to be 80.4%, 12.3% and 0.7%, respectively. Accordingly, the detection of nitrogen and phosphorus in dispersant shows that dispersants should be used with caution in coastal waters, with relation to eutrophication. The biodegradability of dispersant expressed as the ratio of BOD5/TOD was found to be 11.0%. As the mix ratios of dispersant to Bunker-A oil (3 mg/l) and a mixture of Bunker-B oil (3 mg/l) were changed from 1:10 to 5:10, the biodegradabilities of a mixture of Bunker-A oil with dispersant and Bunker-8 oil with dispersant increased from 2.1% to 7.2% and from 1.0% to 4.4%, respectively. Accordingly, the dispersant belongs to the organic matter group of middle-biodegradability while mixtures in the mix ratio range of 1:10-5:10 belong to the organic matter group of low-biodegradability. The deoxygenation rate constant (K1) and ultimate biochemical oxygen demand (L0) obtained from the biodegradation experiment and Thomas slope method were found to be 0.125/day and 2.487 mg/l for dispersant (4 mg/l), respectively. K1 and L0 were found to be 0.079-0.131/day and 0.318-2.052 mg/l for a mixture of Bunker-A oil with dispersant and to be 0.106-0.371/day and 0.262-1.106 mg/l for a mixture of Bunker-B oil with dispersant, respectively, having 1:10-5:10 mix ratios of dispersant to Bunker-A oil and Bunker-B oil. The ultimate biochemical oxygen demands of the mixtures increased as the mix ratio of dispersant to Bunker-A, B oils changed from 1:10 to 5:10. This suggests that the more dispersants are applied to the sea for the cleanup of Bunker-A oil or Bunker-B oil, the more the dissolved oxygen level decreases in the seawater

Abstract
Work on salt-marsh plants has shown that the low-boiling fractions of crude oil are the most toxic. Fresh crude oil is more toxic than weathered oil. Further evidence from the literature is reviewed: oils vary in their toxicity according to the content of low-boiling compounds, unsaturated compounds, aromatics, and acids. The higher the concentration of these constituents, the more toxic the oil. All undiluted emulsifiers tested were more toxic to plants than fresh Kuwait crude oil, but none caused permanent damage at concentrations of less than 10%

Abstract
Emulsifier treatment, burning, and cutting have been experimentally investigated as possible cleaning methods for oiled salt-marsh vegetation [Spartina and Puccinellia]. The results given show that none of these methods decrease the damage due to the oil, and they may increase it. In general it is, therefore, best to leave oiled salt marsh to recover naturally