Dispersants Bibliography

Abstract
Toxicity testing of oil spill dispersants was undertaken on the sand shrimp Palaemon pacificus collected from several locations. Results showed that organisms collected from different areas had different responses when exposed to similar concentrations. Similar sizes of the shrimp showed similarities in sensitivity to exposure concentrations. Authors describe the test system and equipment used in experiments, and present equations for explaining differences in survival rates

Abstract
Prior to 1981, manufacturers of oil spill dispersants wishing their products to carry the South African Bureau of Standards (S.A.B.S.) mark of approval or to conform to the applicable S.A.B.S. specification had to have the testing undertaken in the United Kingdom. A new test was introduced in the United Kingdom in 1975, and this and several other tests in use worldwide are reviewed. After consideration of the requirements of a dispersant toxicity test, the necessary modifications for the South African situation are detailed. Results show that the test is comparable with those in use overseas as regards licensing purposes, but there are still basic research problems on dispersant use to be overcome

Abstract
The effect of various states of weathering (no weathering, 20% evaporatively weathered, and emulsification) on the effectiveness of oil dispersants Corexit 9527 and 9500 in dispersing Alaska North Slope crude oil into the water column was tested under laboratory conditions at a combination of realistic subarctic salinities and temperatures. A modified version of the swirling flask effectiveness test was conducted at temperatures of 3, 10 and 22 °C with salinities of 22‰ and 32‰. Petroleum dispersed into the water column following application of dispersant was measured by gas chromatography with flame ionization detection. Based on comparison of unresolved complex mixtures, dispersants dispersed less than 40% of the fresh oil and less than 10% of the weathered oil and were most effective (25–75%) when used to disperse a stable oil/water emulsion at 10 °C. At the combinations of temperature and salinity most common in the estuaries and marine waters of Alaska, dispersants effectiveness was less than 10%, the detection limits of the tests. The results indicate that oil weathering state, seawater salinity and temperature are important factors affecting dispersant performance, however because our laboratory tests were conducted at low mixing energy, considerable caution should be used in extrapolating these laboratory studies to field conditions

Abstract
Experiments on the effects of crude oil and commercial non-ionic emulsifiers, alone and in mixture, on the marine phytoplankton, Platymonas tetrathele, are reported. Growth rates were reduced by all the compounds tested in concentrations above 50 ppm, and an emulsifier with an aromatic solvent induced a very long lag phase in treated cultures. The toxicity of mixtures was close to that of the emulsifier component and lower than that of the crude oil alone. The ecological implications of such pollution are discussed

Abstract
This report describes Corexit 7664, an improvement in dispersant options over previous and more toxic alternatives. Corexit 7664 is biodegradable and found to be non-toxic to tropical fish and shrimp at 10,000 ppm for 24 hours. It can be released by air or at sea, and can be used on a variety of crude oils and distillated petroleum products. Limitations of Corexit 7664 are described as not being effective on residual materials and oil fractions with high viscosities, and that the water surface needs to be agitated for it to perform well on spills

Abstract
Higher tolerance (acclimation phenomena, adaptation) to oil (Tunisian crude oil) and oil dispersant (Finasol OSR 2, Finasol OSR 5), can be induced in Artemia salina after pre-exposure to these toxicants. The higher tolerance includes acute toxicity (LC50) and sublethal physiological dysfunctions (respiration). High pre-exposure concentrations lead to rapid induction of acclimation phenomena but the higher resistance is partly lost after exposure of the acclimated animals to clean sea water. Exposure to low concentrations of the toxicants induce a slow appearance of adaptation phenomena, but higher tolerance does not disappear after exposure to clean sea water and is strengthened after the detoxification period

Abstract
The available methods for the clean-up of oil (and certain chemical) spills at sea are considered and recent developments in two fields namely, dispersant application and oil recovery, are covered in detail. The application of dispersants is shown to be restricted by the viscosity of the oil on the water which increases rapidly due to oil in water emulsion formation. Samples of oil emulsion recovered of the water can show poor response to dispersants when the viscosity increases to about 7,500-10,000 cP depending on the dispersant used and the nature of the crude oil. The development and limitations of recovery systems are considered with reference to the Springsweep system. Mention is made to netting systems for use with oils which are semisolid on the surface of the water

Abstract
Co-operation between the appropriate government authorities responsible for coordinating and controlling oil pollution clean-up and for licensing oil spill dispersants, the dispersant manufacturers, and the oil industry meeting as the Institute of Petroleum Marine Environmental Committee's Dispersant Working Group, has led to a revised specification for oil spill dispersants being agreed, which should come into effect in May 1983. The method of assessment of dispersant efficiency has been improved and evaluated in a co-operative programme of work and limits proposed for the Efficiency Index Test for the three types of dispersants described in the Specification

Abstract
An adaptation of the Labofina test method for laboratory testing of oil spill dispersants has led to the development of new dispersants of considerably greater efficiency. The creation of new dispersants has resulted in issuing new specifications for oil slick dispersants. The amended test and information regarding the new specifications are detailed in this report

Abstract
An account is given of beach trials in which three dispersant concentrates were used at low ambient temperatures to treat test patches of various oils and water-in-oil emulsions. Subjective assessments of the manner and rate of dispersion of pollutant into the sea were aided by control experiments without dispersant, and with the dispersants premixed with medium fuel oil. For successful treatment of residual thin layers of pollutants with approved dispersant concentrates there appears to be no upper limit on the viscosity of semi-fluid oils and emulsions

Abstract
Following preliminary experiments on the toxicity of four hydrocarbons to barnacles, more detailed studies were carried out using kerosene and the oil-spill remover BP 1002. For both species of barnacles used, the percentage non-motility and actual mortality of the naupliar larvae and adults were related to hydrocarbon dosage and exposure period; the nauplii were killed at lower concentrations than the adults. BP 1002 was the most toxic of the compounds tested; the toxicity of kerosene was comparatively low

Abstract
Dispersants are a proven oil spill response technique. Since effective use of dispersants is often limited to a few days following a spill, timely and effective dispersant application is a major requirement for dispersant use. Despite the advantages of aircraft over vessels in applying dispersant to large or remote spills, vessels do offer certain advantages over aircraft. These include wide and ready availability in port and marine terminal areas, lower cost, ease of deployment, high degree of spray control and accuracy. These advantages often result in vessel platforms being the preferred application method, especially for nearshore, smaller spills. Therefore, vessel-based systems should not be overlooked in contingency planning, as these systems can often be a viable and effective option for sustained dispersant application in certain oil spill simulations. There are three major types of vessel application systems: 1) spray arm systems; 2) fire monitor systems, which are systems designed to spray water or fire-fighting foam; and 3) single nozzle neat dispersant application systems. The advantages and disadvantages of each system are reviewed and evaluated. Certain vessel characteristics beneficial for dispersant application are also discussed. To be most effective, vessels generally should 1) have sufficient dispersal payload or the ability to be re-supplied effectively, 2) be rapidly mobilized shortly after dispersant use approval, and 3) be located close enough to the spill scene to arrive within the required time when dispersant use is effective. Finally, the major vessel dispersant application operational guidelines are summarized

Abstract
Criteria for the use of chemical dispersants in the treatment of oil spills threatening coastal areas are outlined, and experiments are reported, with tabulated and graphical results, on the relevant properties of Corexit 8666, Gamlen Sea Clean, G. H. Woods Degreaser-Formula 11470 and Sugee 2, each examined alone and in a 1:1 combination with Arabian crude oil, added to samples of water from Halifax harbour, Nova Scotia, to give concentrations of 1.25 per cent dispersant, with or without 1.25 per cent oil. When added as the sole carbon source, all the dispersants supported growth of the indigenous bacteria at both 10 °C and 25 °C; none was toxic but two of the products extended the lag phase, although this effect was reduced markedly by the addition of crude oil; in the presence of oil or oil and dispersant, the bacterial population changed and Pseudomonadaceae and Achromobacter spp. predominated. Based on the n-alkane fraction of the oil, degradation depended on the type of dispersant applied; Sugee 2, which has the poorest emulsifying capacity, promoted degradation slightly, while the other three dispersants inhibited degradation; the percentage degradation of oil and oil plus dispersant was greater at 25 °C than at 10 °C

Abstract
A procedure for evaluating the effectiveness of oil-dispersing chemicals has been developed. Using the apparatus originally designed for the Navy specification for solvent-emulsifiers, test conditions were adapted to correspond more closely to typical environmental conditions. Test conditions having the greatest effect on dispersant performance included: type of oil, composition of salt water solution, degree of agitation of chemical/oil mixture, and the degree of contact between chemical and oil prior to agitation. Results from this modified procedure, the Simulated Environmental Tank (SET) Test, correspond well with results from simple field tests. Field tests have limited precision and reproducibility. This lack of a reliable index of field performance with which to compare laboratory results hinders refinement of standard test procedures. The SET test, which produces results corresponding favorably with field performance, to the extent field performance can be determined, and which simulates typical environmental conditions, is proposed as a meaningful interim solution to this problem of dispersant evaluation

Abstract
Marked declines in the numbers/percentage cover of four common species of littoral organism occurred between July 1978 and July 1979 on mainland shores in Bantry Bay, Ireland. Regular monthly monitoring has enabled most of these declines to be related to natural phenomena rather than to pollution of the Bay by oil from the Tanker Betelgeuse which exploded in January 1979. Only Pelvetia canaliculata and recently settled spat of Balanus balanoides show any indication of having been affected by oil/dispersants. By contrast, the North shore of Whiddy Island was severely affected

Abstract
Four dispersants (Corexit 7664, Berol TL-188, Berol TL-198 and BP 1100-X) were tested on six marine species (fishes Gasterosteus aculeatus, Phoxinus phoxinus, bivalves Cardium glaucum, Mytilus edulis, and crustaceans Gammarus spp., Neomysis integer) found in the littoral zone of the Baltic Sea. At concentrations above 1700 ppm, significant differences in toxicity were noted between Corexit 7664, Berol TL-188 and Berol TL-198, all water-based dispersants. Researchers also compared effects between water-base dispersants and BP 1100-X, an oil-based dispersant. For 96-h LD50 values, Corexit 7664 results were 1000ppm for fish, 2000ppm for bivalves, and 10,000ppm for crustaceans. BP 1100-X results were 10,000ppm for fish, 2000ppm for bivalves, and 150ppm for crustaceans

Abstract
In order to understand the fate, distribution and composition of Norman Wells crude oil and Corexit 9527, alone and in combination, a series of tests were undertaken in five lined ponds containing sandy gravel sediment and mesotrophic water. Two ponds were used for an oil/dispersant treatment of 100 ppm crude and 20 ppm dispersant. Systematic sampling took place over the space of a year, monitoring water surface, water column, sediment, pond liner, and biota. 10% of the oil persisted for weeks in the oil/dispersant treatment, and then most of dispersed oil rose to the water surface, only to sink to the sediment in time. After one year, it was estimated that 45% of the oil in the treatment had degraded. Oil composition did not appear to be affected by presence of the dispersant

Abstract
Goups of 2- and 3-year-old Oncorhynchus kisutch were tagged and exposed in seawater to sublethal concentrations of crude oil, dispersed oil, or dispersant alone, for periods of 1 h, and then were released in seawater about 5 km from their home stream. Results show that O. kisutch's homing success and speed of return were not impacted by any of the treatments

Abstract
Accidental oil spills from ships or rigs and inputs of effluent such as production formation water (PFW) are key perceived threats to tropical biota from industry activities. Scleractinian corals are an important functional component of tropical reefs and the abundance, diversity and resilience of coral communities can be used as an indicator of ecosystem health. In this paper, we report the effects of petroleum products, including water accommodated fractions (WAF) of crude oil, PFW and dispersant (Corexit 9527), on fertilization and larval metamorphosis of the widespread scleractinian coral, Acropora millepora (Ehrenberg, 1834) in laboratory-based assays. At 20% v/v PFW fertilization was inhibited by 25%. This concentration was equivalent 0.0721 mg l-1 total hydrocarbon (THC). In contrast, larval metamorphosis was more sensitive to this effluent, with 98% metamorphosis inhibited at the same concentration. Crude oil WAF did not inhibit fertilization of gametes until dispersant was introduced. Dispersed oil was slightly more toxic to fertilization than dispersant alone, suggesting toxicity to that event may be additive. The minimum concentration of dispersed oil which inhibited fertilization was 0.0325 mg l-1 THC. Larval metamorphosis was more sensitive than fertilization to crude oil. Although crude oil and dispersant inhibited larval metamorphosis individually, this toxicity was magnified when larvae were exposed to combinations of both. Crude oil inhibited metamorphosis at 0.0824 mg l-1 THC and at 0.0325 mg l-1 THC when dispersed in 10% v/v (dispersant/oil). Management of petroleum-related risks to spawning corals should consider not only the occurrence of the annual coral spawning event, but also the subsequent 1–3-week period during which most larval metamorphosis and recruitment occur

Abstract
Changes in abundances of marine organisms are recounted from three oil spills that impacted Milford Haven in the 1960s. Alterations in community structure were found to be similar following the Torrey Canyon incident, although to a much greater extent due to the size and distribution of the spill, and the post-spill treatment of shorelines

Abstract
Damage to Cornish seashore life resulting from the chemical dispersal of oil spilled from the Torrey Canyon is often taken as typical of dispersant use, although primitive mixtures were badly misapplied there. When more modern dispersants are used with care, as in recent Milford Haven spills, serious consequences can be avoided. All effective dispersants offer some biological hazards, especially to sedentary or planktonic filter-feeding animals, which are not revealed by short-term acute toxicity testing. Spilled oil should therefore be removed mechanically whenever possible. Careful spraying is recommended to prevent an oil slick reaching the shore and to protect seabird colonies. It may also be necessary on rocky or built-up amenity areas but should be avoided on coasts rarely visited by humans and distant from bird colonies. Spraying may worsen matters on sandy shores, while any form of treatment will further damage oiled salt marshes