Dispersants Bibliography

Abstract
Emulsion inhibitors can be used to inhibit the emulsification process or to break already formed water-in-oil emulsions after an oil spill. Institut Français du Pétrole (IFP) has developed a methodology based on simple laboratory tests. It involves the assessment of inhibitors performances by the rotating flasks method, the characterization of the potential leaching from the oil to the water phase and the evaluation of the dispersant effectiveness by the IFP dilution test

Abstract
Phaseolus vulgaris L. cv. Black Valentine when sprayed with Corexit dispersants shows a rapid inhibition of photosynthesis. The plant retains the ability to translocate fixed carbon, and this involves mobilising previously fixed carbon in the sprayed leaf or the repartitioning of carbon from unsprayed regions of the plant towards the growing sink regions. The ability to maintain carbon translocation while photosynthesis is declining maximises the regrowth potential of the plant

Abstract
Change is the hallmark of progress. In science, progress, i.e., change, is typically denoted by the advance of technology. The evolution of each new technology encourages the stabilization and in some instances the demise of other related technologies. Development of bioremediation as a technology for oil spill abatement is a clear example of waning interest in one technology, chemical dispersants, and the advancement of another. Oil spill research at the Environmental Protection Agency (EPA) has followed a similar trend of expansion and stabilization with funding of dispersant research declining in recent years. The nutrient enrichment studies conducted in Alaska subsequent to the grounding of the EXXON Valdez was the most significant, single event to spur the advancement of the technology known as bioremediation. Since that time, research on bioremediation agents has moved forward, while research on oil spill dispersants has plateaued within both the Federal and private sectors. Although bioremediation remains as the primary focus of EPA's research program in oil spill pollution, studies have been conducted to enhance our knowledge of dispersants and to minimize potential hazards associated with their use. Within the Agency (EPA), the current research effort on dispersants is focused primarily in three areas: (1) spill response and contingency planning; (2) re-evaluation of regulatory test methods for efficacy and toxicity; and (3) risk estimation. This discussion will highlight toxicological research on dispersants as it relates to the latter two categories, regulatory test methods and risk estimation

Abstract
In anticipation of an oleophilic 'fluff' based on a mixture of fabric and rubber being used to treat marine oil spills, experiments were conducted with various concentrations of the 'fluff' in comparison with seawater solutions of the detergent BP 1100 and oil suspensions. The effects of oil treatment by both methods were also investigated. The 'fluff' appears to be relatively innocuous, and is not more toxic than BP 1100 at the same concentration. At high concentration it is less toxic than BP 1100. 'Fluff'/seawater mixtures caused death by mechanical effects, blocking nephropores or branchial chambers and this was potentiated by the oil making the 'fluff' sticky. On seashores, 'fluff' is unlikely to penetrate burrows and so would not exert this effect

Abstract
5 oil dispersants and a sample of paraffin were devoid of mutagenic activity in the Ames reversion test, with and without S9 mix, using 7 his- S. typhimurium strains (TA1535, TA1537, TA1538, TA97, TA98, TA100, TA102). However, 3 dispersants produced direct DNA damage in E. coli WP2, which was nonrepairable in repair-deficient strains (WP2uvrA, CM871, TM1080), as shown by two different DNA-repair test procedures. The uvrA excision-repair system was in all cases the most important mechanism involved in repairing the DNA damage produced by oil dispersants, while the combination of uvrA with other genetic defects (polA, recA, lexA) decreased the efficiency of the system. The observed genotoxic effects were considerably lowered in the presence of S9 mix containing liver S9 fractions from Aroclortreated rats. The sample of oil dispersant yielding the most pronounced DNA damage in repair-deficient E. coli failed to induce gene sfiA in E. coli (strain PQ37), using the SOS chromotest, or mitotic crossing-over in Saccharomyces cerevisiae (strain D5). The direct toxicity of the oil dispersant to both bacterial and yeast cells was markedly decreased in the presence of rat-liver preparations. These two short-term tests were effective in detecting the genotoxicity of both direct-acting compounds (such as 4-nitroquinoline N-oxide and methyl methanesulfonate) and procarcinogens (such as cyclophosphamide, 2-aminoanthracene and 2-aminofluorene). Moreover, the SOS chromotest was successfully applied to discriminate the activity of chromium compounds as related to their valence (i.e. Cr(VI) genotoxic and Cr(III) inactive). Combination of oil dispersants with Cr(VI) compounds did not affect the direct mutagenicity to S. typhimurium (TA102) of a soluble salt (sodium dichromate) nor did it result in any release of a water-soluble salt (lead chromate), as also confirmed by analytical methods. On the other hand, exposure to sunlight tended to decrease, to a slow rate, the direct genotoxicity of an oil dispersant in the bacterial DNA-repair test

Abstract
Artificial intertidal mudflats were used to study effects of "Forties" oil, a dispersant and dispersed oil. Oil was added in a 0.5 and a 0.1 mm layer. In the latter treatment, 2 exposure times were used. The effects on the development of stocked macrobenthic infauna species are presented. As the experiments lasted 10 months, both short- and long-term effects and interactions could be investigated

Abstract
South Louisiana crude was applied to replicated plots in a Louisiana Spartina alterniflora salt marsh. Various marsh restoration methods were evaluated for mitigating the impact of crude oil on the marsh biota. Oiling the marsh caused no reduction in macrophyte production as compared with the non-oiled plots. Thus the cleanup treatment showed no beneficial effects to S. alterniflora. Likewise, there was no oil-induced mortality for the marsh macrofauna or meiofauna. In Louisiana Gulf Coast salt marshes, which have a low sensitivity to oil as shown in this study, the best response is no cleanup action at all

Abstract
The mechanical action of breaking waves and turbulence cause oil to break up into small droplets and diffuse in the water column. The droplet size is important in view of the dispersion stability, the interaction with marine life, and the uptake by sediment. Laboratory measurements were performed on the droplet size distribution in various conditions. The droplet size distributions observed were strongly dependent on the turbulence energy level and on the duration of the turbulent state. Other distinct parameters were the oil type, weathering state and temperature, all being reflected in the single parameter of viscosity. The droplet size was independent of the salinity of the water, and the oil concentration. The droplet size distribution was similar for droplets generated from submerged oil lumps and those generated from a surface layer

Abstract
At the Delft Hydraulics Laboratory a laboratory flume has been constructed to aid research into natural and chemically induced dispersion processes as well as to test the effectiveness of dispersant in specific conditions. The flume allows the selection of variables and conditions, for instance, the generation of nonbreaking and breaking waves and currents, the variation of temperature, salinity, oil layer thickness, dispersant spray droplet size, and the droplet impact on the slick surface. The flume has been verified with empirical data gathered from an extensive sea survey on the natural and chemical dispersion of a number of oil slicks. The field experiments on natural dispersion can be modeled satisfactorily in the flume with respect to the formation of oil droplets from the oil slick and the initial intrusion in the water column. The further mixing of oil droplets in the water mass are to be calculated from diffusion theories and other transport processes. Field experiments on the natural and chemical dispersion of 10 artificial oil spills in the North Sea led to the remarkable conclusion that spraying an oil slick with chemical dispersant did not enhance the (natural) dispersion process, while a premixed dispersant in oil was very effective. The ineffectiveness of sprayed dispersant could not be explained from a limited series of experiments performed in the laboratory flume on the effects of evaporation, photo-oxidation, emulsification, and layer thickness on natural and chemical dispersion

Abstract
In the case of an oil spill, knowledge is needed of the natural dispersion behavior of the oil in the particular situation for decision making on the application of chemical dispersants. Small-scale and full-scale laboratory measurements were performed on the natural dispersion rate Q, droplet size distribution do(f), and intrusion depth zi, for a surface oil slick broken up by breaking waves and the breakup of submerged oil (submerged spill) in a turbulent ambience. Empirical relations were derived for Q, do(f), and zi as a function of oil type, weathering state, oil layer thickness, breaking wave energy, temperature, and water salinity

Abstract
1. Cardiac activity and oxygen consumption increased when C. maenas were exposed to a 20% solution of the water-soluble fraction of Fortes crude oil, a 10% solution of the dispersant BP1100WD or a combination of both. 2. Normal feeding behaviour was disrupted. 3. Perfusion indices (Q/Vo2) decreased as locomotor activity increased following exposure to crude oil. However, exposure to dispersant or dispersant + crude oil resulted in elevation of perfusion index despite crabs becoming active. 4. All test animals survived for at least 6 weeks following exposure to the pollutants. 5. The acute, sublethal effects of dispersant and dispersant + crude oil were more severe than the effects of crude oil alone

Abstract
Several kinds of oil dispersers have been used in time of emergency, and also when a tanker has to throw the loaded oil into the sea. This practice, however, may be harmful to fish living in the waters, and the pollution on fish meat caused by the oil and dispersers have also become of great concern. From this viewpoint the author tested 4 kinds of commercial dispersers with carp, Cyprinus carpio. 2 of them were highly toxic for the fish; at a level less than 20 ppm half of the fish died after 48 hr, the other 2 were relatively non-toxic and 600 ppm showed the same effect as in the above condition. Dispersers containing mineral oils in their ingredients showed an oily polluted smell on the fish meat. Analyzing the polluted meat gas chromatographically, the chromatogram interpreted well the causal dispersers which were olfactory not easily distinguishable from one another

Abstract
Laboratory tests for the assessment of oil spill dispersant efficiency cannot exactly simulate the natural conditions existing at the marine air-water interface. On the other hand, large scale trials in the open sea are so complex and expensive that they can hardly be considered as a routine method to evaluate dispersant efficiency at sea. In this paper we describe the procedure of a middle-scale field test to be run in the open and sheltered waters of harbors or roadsteads. Three boats heading into the wind and sailing on line at a constant speed are used for successively: spreading the oil on the surface of the water; overspraying this immediately with the test dispersant; and continuously sampling the water at three different depths for hydrocarbon measurements. The spray boat is equipped to discharge dispersant ranging from highly diluted to neat concentrates by means of a volumetric pump and one boom with four spray nozzles mounted near the bow. Agitation of the oil-dispersant mixture is made by a net of floating plastic chains towed astern. The sampling system consists of a small catamaran rigged ahead of the bow of the analysis vessel. The samples, continuously collected from 0.4, 0.7, and 1.0 m depths, are monitored by one line turbidimetry for the first two levels and UV fluorometry for the deepest one. Fractions of the sampling flows are recovered to check the analyzers and to measure separately the hydrocarbons and surfactant contents. In the first series of tests, the parameters investigated were: oil viscosity in the range of 50 cs (a reconstituted topped crude oil) to 2,000 cs at 20° C; dispersant type, including conventional and concentrates; dispersant concentration, from 10 percent aqueous to undiluted concentrate. In addition, the performances of various commercial dispersants could be compared under similar conditions. Three main conclusions were drawn from this work. 1) The viscosity limitation falls at about 1,500 cs with the oils investigated. 2) Concentrate dispersants applied undiluted are more efficient than when pre-diluted with water, but the distribution of the dispersant upon the slick is more subject to wind and sea-state. 3) Concentrate dispersants seem to work better than conventional ones, even on the more viscous oils

Abstract
Although dispersants are used in different countries, it appeared from recent international meetings that more knowledge concerning dispersant effectiveness is still needed for a better response to oil spills. Large field trials which were conducted during the past two years raised some questions as to how dispersants work at sea. Even though the results obtained in different laboratory tests are generally in good accord, significant discrepancies of practical interest may be observed because of variations in the experimental conditions. With EEC support, an experimental program has been conducted by CEDRE and Institut-Français du Pétrole (IFP), both with the already-described French middle scale field test and with different laboratory tests (U.K. and French standard tests and the recently developed dilution test). With the objective of correlating the results obtained in field tests and in laboratory tests, several parameters were investigated at sea with different dispersants: the type and viscosity of the oil, slick thickness, and oil to dispersant ratio. Based mainly on the results obtained in the laboratory with dilution tests, new aspects of dispersant behavior have been identified, relating to the nature of the oil and the energy input

Abstract
Following detailed investigation into the need and practical issues involved, The Global Alliance successfully implemented a cost effective solution to provide a Tier 2 regional aerial dispersant and surveillance service in West and Central Africa (WACAF). This paper will provide a case study of i) The practical issues concerned with the implementation of the project from conception, through development and implementation. Transboundary issues concerning the logistics and deployment of the service and location of depots are discussed along with the need for the oil community to work closely together and with national authorities are discussed. ii) The solution and rationale adopted to enable an effective response and cost effective service. iii) The response and lessons learnt by The Global Alliance following deployment of the service to two live spills in the region. Video footage of the aircraft trials and an actual spill response will be provided along with details of the aircraft and associated equipment

Abstract
As environmentalists, we must constantly be aware of, and recognize the potential pollution problems that might result from an oil spill cleanup approach or system. Based on biodegradability and ultimate oxygen demand data developed by the Edison Water Quality Laboratory as well as others, it would appear that more than knowledge of toxicity and emulsion efficiency should guide our decisions regarding the use of chemical dispersants for oil spill cleanup

Abstract
In January 1978, the tanker Brazilian Marina, while under tow, struck rock in São Sebastiao Channel, São Paulo, Brazil, and spilled approximately 10,000 tons (3,000,000 gallons) of 31.4 API gravity Kuwait crude. Prevailing winds and currents carried the oil in a northeasterly direction, causing pollution of the coastal embayments and beach areas in the States of São Paulo and Rio de Janerio. The most severly impacted areas were those of Ubatuba, São Paulo, and the coastline along the southwestern shore of the State of Rio de Janeiro. In an attempt to protect recreational and other public use areas, particularly the popular beaches of Ubatuba, undiluted dispersants were applied to remove oil accumulations from the shoreline. This response action while it cosmetically removed oil from the surface of the beaches, caused the oil to penetrate more deeply into the underlying sand, thus compounding the pollution and aesthetic problems attributable to the spill incident. Chemical analysis of detergent-treated and oil-contaminated sand samples from Ubatuba beaches, as well as samples from a beach area in the State of Rio de Janeiro, located approximately 200 kilometers (124 miles) from the spill site, found similarities between the environmental samples and the suspected source, the Brazilian Marina. Preliminary follow-up studies, conducted seven months after the incident, verified the persistence of the detergent-treated oil in the beach sand

Abstract
The EPA's OHMSETT facility has developed a rapid field test that includes some of the theoretical aspects and conditions of dispersion at sea. This Field Dispersant Effectiveness Test (FDET) has been used to evaluate the dispersibility of various commonly-transported oils and make a database for dispersant selection and application. The FDET is designed to generate droplet sizes that closely resemble the dispersion of oil occurring at sea. A fixed mixing intensity and time induces the effects necessary to produce the dispersion and reveal the effectiveness of the dispersant and dispersibility of the oil. The measurement of the dispersibility of various crude oils with several dispersants have been incorporated into a database. This data will help the officials involved in the control of oil spills to make more informed decisions about the use of dispersants

Abstract
As part of the Baffin Island Oil Spill (BIOS) Project, two experimental oil discharges were made into bays at Cape Hatt at the northern end of Baffin Island. The objective was to allow the comparison of the nearshore fate and effects of an untreated surface oil slick and oil chemically dispersed into the water column. Weathered Lagomedio crude oil (15 m3) was discharged onto the water surface in one bay, and most of the slick became stranded on the intertidal zone under the influence of an onshore wind and ebb tide. The oil thickness averaged about 1 mm on the beach face. The same volume and type of oil premixed with Corexit 9527 in a ratio of 10:1 was pumped into a second bay through a perforated diffuser pipe lying on the bottom sediments. The cloud of chemically dispersed oil contacted the bottom sediments and benthic organisms in the second bay and an adjacent third bay. The total exposure in the water column in the second bay was about 300 µg·g-1·h and about 30 µg·g-1·h in the third bay

Abstract
Toxicity of oil alone is difficult to assess. Unweathered crude may lose volatile constituents to the air within a few hours, during which time light ends may have dissolved and been brought into contact with marine life in areas not directly contaminated by the visible oil. The low boiling aromatics in the crude represent the acute toxic hazard, while the higher molecular weight polynuclear species may be of significance in their long-term effects. In general, the deleterious effect of oil on marine life would appear to be physical rather than chemical. Careful consideration of the solubility of hydrocarbons in water should be made when designing toxicity tests. Chemical characteristics and the action of dispersants are discussed. Environmental parameters to be considered include temp and quantity of suspended solid. Administration of the dispersant is considered, and also the desirability of having a dispersant which could invert the water-in-oil emulsions, transforming the oil into the disperse phase, Toxicity characteristics of dispersants are discussed briefly, and details given of a specification governing the supply of oil spill dispersants, prepared by P.G. Jeffrey

Abstract
In an attempt to understand long-term effects from brief exposures to low-level concentrations of oil and chemically dispersed oil, experiments were conducted recreating conditions of an oil slick passing over a coral reef. After exposures of 1 to 50 ppm concentrations of oil and oil/dispersant mixtures for periods between 6 and 24 hours in the laboratory and field, corals were returned to a natural environment. A year later, corals were recollected from the field and analyzed for linear growth with the alizarin strain method. No significant differences in extension growth or calical shape were noted. However, in summer experiments, calical relief was depressed following some treatments

Abstract
An oil spill dispersant testing program was initiated in 1973 to evaluate the toxicity and dispersing effectiveness of dispersants submitted to Fisheries and Environment Canada for approval prior to use in Canadian waters. Screening toxicity tests with rainbow trout (Salmo gairdneri) were performed initially on 19 dispersants. Thirteen were considered sufficiently nonacutely toxic to justify further evaluation using methods and criteria of the Canadian Guidelines on the use and acceptability of oil spill dispersants. Twelve of the 13 dispersants had 4-day LC50’s to rainbow trout ranging from 50 to 39 360 mg/litre, while the 4-day LC50’s twelve dispersant/No. 2B fuel oil (1:1) mixtures ranged from 35 to 300 mg/litre. Six dispersants passed the toxicity criteria with 4-day LC50’s greater than 1000 mg/litre for the dispersant and 100 mg/litre for the dispersant/oil mixture. Effectiveness tests were conducted with No. 2B fuel, Largo Medio crude oil, and medium and heavy Bunker oils. Twelve dispersants passed the effectiveness criterion by dispersing greater than 65 percent of one or more types of oil. Effectiveness of dispersants varied with oil type and with temperature and salinity of the water. The dispersants BP1100X, Corexit 8666, Drew Chemical OSE 71, Drew Chemical OSE 72, Oilsperse 43, and Sugee #2 passed both the toxicity and effectiveness criteria and were placed on the Canadian standard list of acceptable oil spill dispersants. Acute lethal toxicity tests with BP1100X and Sugee #2 showed that rainbow trout in fresh water were more sensitive than two marine fish, Fundulus heteroclitus and Menidia menidia, while fourth stage larval lobsters, Homarus americanus, were the least sensitive