Dispersants Bibliography

Abstract
This paper describes preliminary investigations into the effects of oil pollution on the fauna and flora of inter-tidal sediments. To date we have done little work in this field, and our conclusions will relate more to future research needs than to our own investigations. The questions relevant to the problem are as follows. (1) What lives in the inter-tidal sediments of Milford Haven? Milford Haven is specified, as this is the area being studied. Without an understanding or the normal beach, we cannot answer questions about an abnormal one. The survey described here has given us some knowledge of the distribution of the larger animals, although we have not studied the very small organisms (the meiofauna and microfauna), but we do not know very much about the way in which their numbers are maintained. (2) What effect will oil and emulsifier pollution have no the fauna and flora of intertidal sediments? With regard to emulsifiers, we know that the application of BP 1002 will cause substantial mortalities amongst many species. Treatment with BP 1100 will cause less damage, although the compound is still toxic. We cannot say how severe the effects of differing amounts of emulsifier cleansing will be. We do not know what effect oil alone will have on these organisms. (3) What ecological changes will follow damage caused by pollution? We cannot answer this question at present. There is considerable need for future research. How urgent is an understanding of these problems in Milford Haven? We cannot give an accurate account of changes which have occurred since the oil industry came to the area. However, we have noted that many people collect animals from sandy and muddy shores, either for eating or for use as bait. We have never heard of any complaints about mass mortalities in areas used for this purpose. On the other hand, oil-tained cockles (as well as fish) have been encountered, and it has also been observed that, following light pollution by oil, or by oil and emulsifier mixtures, polychaete worms used as fishing bait are often flaccid and fragile, if not actually moribund or dead. Research into the effects of oil and emulsifier pollution on the fauna and flora of sandy and muddy shores is not easy, and in the present research most attention has been given to the problems of rocky shores, which are more easily understood. Nevertheless, such research is needed, not least because the populations of inter-tidal sediments are generally of more direct interest to those who visit the seashore

Abstract
Seventy-six samples of coastal sediments collected in the Straits of Messina were studied in order to evaluate the effects of an oil spill and the consequent "clean-up" operations on heterotrophic aerobic bacteria. In addition, in vitro tests were carried out ot estimate the effects of five dispersants on the growth and oil degrading capacity of marine strains isolated from the same sediments

Abstract
The use of oil dispersants in estuaries was studied in terms of the physical, hydrological and biological nature of the estuaries, the physico-chemical fate of the treated hydrocarbons and the environmental consequences of dispersant use. The principal effect is the increased penetration of dispersed hydrocarbons into the sandy sediments. Dispersants also tend to form layers of regrouped particles which are difficult to remove in cleaning operations. Taken in conjunction with the toxicity and other harmful environmental effects, these considerations have resulted in recommendations that dispersants should not be widely used in estuaries, and when they are, careful control and selection of sites should be applied

Abstract
Control data on the ice algal bloom at Cape Hatt, northern Baffin Island, during 18 May-2 June 1982 were typical of those at other arctic locations. Ice algae were dominated by pennate diatoms (80% of total cells), particularly Nitzschia grunowii (55%) and N. frigida (15%). In various locations and sampling periods, cell densities ranged from 1.7-384.7 x107 cells·m-1, and chlorophyll a concentrations ranged from 3.4-16.7 mg·m-2; both increased over the study period. Mean productivity rates based on particulate radiocarbon fixed were from near zero to 2.95 mgCm-2·h-1. Dissolved organic radiocarbon concentrations were almost always higher than particulate radiocarbon concentrations, probably because of cell rupture. Total (dissolved + particulate) productivity rates were up to 12.7 mgCm-2·h-1, with an overall mean of 4.4 mgCm-2·h-1 in control samples. Productivity and productivity per unit chlorophyll increased during May and decreased slightly by 1-2 June. Undisturbed, enclosed areas of the under-ice surface were treated with oil on 23-24 May. Dispersed oil (Venezuela Lagomedio crude + Corexit 9527, BP CTD, or BP 1100 WD) was in contact with the ice for 5 h, whereas untreated oil and solidified oil (BP treatment) remained in the enclosures for the duration of the study (12 days post-treatment). Sampling was carried out in areas where oil contacted the ice and moved away or in areas near oil that remained in contact with the under-ice surface. Five hours after treatment, oil concentrations in the water within the enclosures were similar (0.15-0.28 ppm) in untreated oil, solidified oil and control enclosures. In contrast, dispersed oil concentrations were 5.8-36.5 ppm. No adverse effects of any oil treatment on ice algae were detected in analyses of group composition, cell densities, chlorophyll a concentrations, productivity, productivity/chlorophyll or ratios calculated to standardize for light effects. Untreated and solidified oil may have stimulated ice algal growth and productivity near (but not in) the oiled areas

Abstract
Meiofauna collected during May 1982 in the soft bottom layer of nearshore landfast ice at Cape Hatt, northern Baffin Island, were dominated by cyclopoid copepods, harpacticoid copepods, nematodes and polychaete larvae (73.5, 15.4, 6.3 and 3.5% of total numbers respectively). Also included were rotifers, gastropod veligers and calanoid nauplii; calanoid nauplii were probably present in the near-ice water and not on or in the ice. Average abundance of all ice meiofauna was 54,000 individuals·m-2. Densities of all meiofauna groups were spatially variable, but only nematodes and cyclopoid copepods showed evidence of progressive temporal change between 18 May and 2 June. Undisturbed, enclosed areas of the under-ice surface were treated with oil on 23-24 May. Dispersed oil (Venezuela Lagomedio + Corexit 9527, BP CTD or BP 1100 WD) was in contact with the ice for 5 hours, whereas untreated oil and solidified oil (BP treatment) remained in the enclosures for the duration of the study (12 days post-treatment). Sampling was carried out in areas where oil contacted the ice and moved away or in areas near the oil that remained in contact with the under-ice surface. Five hours after treatment, oil concentrations in the water within the enclosures were similar (0.15-0.28 ppm) in untreated oil, solidified oil and control enclosures. In contrast, dispersed oil concentrations were 5.8-36.5 ppm. Densities of all copepods and polychaetes decreased dramatically in each dispersed oil enclosure by the second post-spill day, and slight density increases were evident by the tenth post-spill day. Harpacticoid copepods apparently were more sensitive to dispersed oil than were cyclopoid copepods. Densities of nematodes and cyclopoid copepod nauplii were not affected by dispersed oil. Densities of nematodes, polychaetes, and all copepods were not affected by untreated or solidified oil, but there was some evidence of a stimulatory effect of those treatments on some copepod groups and life stages

Abstract
An experimental subsurface release of chemically dispersed oil at Cape Hatt, northern Baffin Island, resulted in short-term, relatively high oil concentrations in the waters of two adjacent bays, whereas untreated oil released onto the surface of a third bay could not be detected in the water below a depth of 1 m. Diver observations revealed no apparent short-term effects of untreated oil on shallow water infauna, whereas marked acute effects on infauna, including emergence from the substrate and narcosis, were apparent in the dispersed oil bays within 24 h of the release. Analysis of systematic airlift samples at two depths (3 and 7 m) in the three test bays and a fourth (reference) bay during the open water seasons of 1980-83 (two pre-spill and four post-spill sampling periods) showed that most affected animals recovered. Neither type of oil release caused any large-scale mortality of benthic infauna. Multivariate analyses showed no significant change in infaunal community structure, and effects attributable to oil were found in only 3 of 72 univariate analyses of density, biomass or size data for individual taxa. A progressive decrease in the condition of the filter-feeding bivalve Serripes groenlandicus in the reference bay (several km distant from the dispersed oil release) was apparently the result of exposure to dilute dispersed oil for several days. A similar effect on condition in the surface deposit-feeding bivalve Macoma calcarea was apparently caused by relatively low oil concentrations in the sediments of the dispersed and surface oil release bays. There were no apparent effects on recruitment in bivalve species with planktonic larvae, but density changes in the polychaete Spio spp. indicated that oil in the sediments of the surface oil release and dispersed oil release bays affected reproductive processes. Effects on the condition of the bivalves and on Spio spp. were still evident two years post-spill in 1983, the last year of sampling

Abstract
An experimental subsurface release of chemically dispersed oil at Cape Hatt, northern Baffin Island, resulted in short-term relatively high oil concentrations in the waters of two adjacent bays, whereas untreated oil released onto the surface of a third bay could not be detected in the water below a depth of 1 m. The only immediate response in epibenthos observed by divers was narcosis in urchins and starfish following the dispersed oil release. Analysis of data from in situ counts in the three test bays and in a fourth (reference) bay during the open water seasons of 1980-83 showed that densities of the starfish Leptasterias polaris were not affected by either oil release and that effects on urchin densities were minor or transitory: Strongylocentrotus droebachiensis apparently made immediate and transitory attempts to avoid dispersed oil in the water and possibly tried to avoid untreated and dispersed oil in sediments two years after oiling. Analysis of airlift samples collected at 3 and 7 m depths in the four bays during 1980-83 showed no major effects of either oil release on densities of epibenthic crustaceans; taxa examined included all crustaceans, all cumaceans, one species of cumacean, all amphipods and eight individual amphipod taxa. The overall trend was toward increases in epibenthic crustacean densities over the study period. Effects that may have been attributable to oil were found in only 2 of 22 analyses of density data for individual taxa. In those cases, effects were minor: untreated oil in sediments apparently altered the depth distribution of Anonyx juveniles, and dispersed oil in the water column apparently had a delayed adverse effect on reproduction in the amphipod family Stenothoidae. Densities of Pontoporeia femorata were not affected by oil, but inspection of size-frequency data indicated a possible delayed adverse effect on its reproduction

Abstract
An experimental subsurface release of chemically dispersed oil at Cape Hatt, northern Baffin Island, resulted in short-term relatively high oil concentrations in the water of two adjacent bays. Untreated oil released onto the surface of the third bay could not be detected in the water below a depth of 1 m. Both releases, however, resulted in measurable contamination of sediments in shallow water. Macroalgae at 3 m depth were sampled by a diver-operated airlift sampler in three treatment bays and in a fourth (reference) bay during the open water seasons of 1980-83 (two pre-spill and four post-spill sampling periods). Biomass, number of species and reproductive condition of the dominant understory algae at 3 m depth did not seem to be adversely affected wither by oil in subtidal sediments or by chemically dispersed oil in the water column. No oil effects were detected in data on the biomasses of total algae or of two of the three species analyzed (Stictyosiphon tortilis and Pilayella littoralis). In the third species, Dictyosiphon foeniculaceus, growth increased in the year following the oil release, either stimulated by low levels of oil in sediments or through natural annual variability. The lack of major effects on macroalgae may have been partly attributable to the lack of effects on herbivores and the vegetative mode of reproduction in the dominant macroalgal species

Abstract
A series of experiments was performed at sea where the effectiveness of dispersants applied from a helicopter was tested on fresh and weathered crude oils released from a surface research vessel. In conjunction with these experiments, remote sensing measurements using an array of airborne optical and microwave sensors were performed in order to aid in the interpretation of the dispersant effectiveness and to obtain quantitative images of oil on the sea under controlled conditions. Surface oil thickness and volume are inferred from airborne measurements using a dual-channel microwave imaging radiometer, aerial color photography, and an airborne oceanographic lidar. The remotely sensed measurements are compared with point sampled data obtained using a research vessel

Abstract
In experiments on the Somerset coast, Forties crude oil and BP 1100WD dispersant were sprayed on to small areas of the rocky shore over a period of several days to stimulate conditions following an oil spill. Detailed observations were made at monthly intervals of marked 0.1 m2 quadrants within (and without) the treated areas. Some areas received oil only, others dispersant only, and the third set received oil followed by dispersant. The experiments were in two parts, the one to simulate a July incident and the other a January incident. Limpets and the small winkles living in and between empty barnacle shells were the most obviously affected organisms. The sites that received both oil and dispersant were most seriously upset, but the oil areas came next. The effect of BP 1100WD on its own as applied in this experiment was relatively slight

Abstract
The successful use of chemical dispersants for treating oilspills requires advance information of product effectiveness, such information being necessary for stock piling in contingency planning. Many existing quality tests are unrepresentative of the conditions at sea. Here, a new method of testing oilspill dispersants is described and compared with a standard Warren Spring Laboratory test for effectiveness. Results show that, although similar in its ability to rank dispersants, the Mackay test could also prove useful for observational work on dispersant/oil/water mixtures and control of mousse formation

Abstract
The biological damage caused by the large oil spill in Bantry Bay and the clean-up measures adopted to deal with it (already reported in the Marine Pollution Bulletin) has been followed up in the months following the oil spill. This report refers to damage to algae and lichens

Abstract
According to the authorization-of-use procedures outlined in the National Contingency Plan (NCP), a state with jurisdiction over navigable waters polluted by an oil spill must concur with the decision to apply dispersants or other chemical oil spill control agents. To be effective, a dispersant must be applied quickly, but reaching consensus among the necessary parties can be slow unless all the participants are well prepared at the outset. Ideally, consideration of dispersant use should take place prior to an emergency in order to reach a timely decision. Several states and Regional Response Teams have active programs that are addressing dispersant use planning and technical and environmental considerations. In several states where the use of dispersants is an emerging issue, there appears to be a willingness to consider their use on a case-by-case basis and a genuine interest in learning more about their effectiveness and toxicity

Abstract
Dispersants have been a controversial oil spill response technique since their introduction during the Torrey Canyon oil spill off the coast of the Untied Kingdom in 1967. Despite reductions in the toxicity of dispersants and improvements in their application since then dispersants have not been used extensively in the United States because of logistical difficulties, unfavorable weather conditions, and a lack of demonstrated effectiveness during actual spill conditions. In addition, there is a widely held perception in the Untied States that dispersant use has been limited by complex authorization procedures. This paper reviews the dispersant policies of several European nations and Canada and compares them with those of the United States. Recent developments in U.S. dispersant policy are outlined, particularly those designed to expedite decision making. This paper concludes by examining some recent U.S. oil spills in which dispersant use was considered

Abstract
Percentage conidial germination and germ-tube length in the marine fungus Zalerion maritimum decreased significantly as the concentration of oil spill dispersant (Corexit 9527, Enersperse 1583 and Slickgone LTS) increased from 0-100/1000 ppm. Preliminary investigations using transmission electron microscopy reveal new evidence of ultrastructural damage in conidial cells caused by Corexit 9527

Abstract
Maine microplankton was observed for responses to oil and oil/dispersant mixtures in enclosed environments (water columns 20 m long, 0.78 sq m surface). Compared to effects from oil exposure, addition of an oil/Corexit 9527 mixture caused a more rapid depopulation of ciliations of the oil-derived material. However, dispersed oil appeared less harmful to the ciliates and the dinophysids than oil alone. Myrionecta rubra appeared to be less sensitive to dispersed oil than the heterotrophic ciliates. As the heterotrophic ciliates never reappeared at 0.5 m in either the oil bag or the oil/dispersant bag but reappeared at the end of the experiment in the oil/nutrient bag, the authors assume that the nutrients negated the effects from the oil

Abstract
Field tests are of major importance for dispersant product evaluation in addition to laboratory effectiveness studies. To investigate the correlation between laboratory and large scale field tests, two series of small scale sea trials were initiated by the Norwegian Oil Pollution Control Research and Development Programme. The field tests comprised the application of sea water diluted dispersants as well as neat application from a boat. A total of six dispersants were tested on four oil types. An attempt was made to correlate the field test results with three laboratory test methods. Results showed that there is poor correlation between effectiveness results obtained from three different laboratory test systems, and between results from field and laboratory tests. There was, however, a fairly good correlation between the mean results from the three laboratory tests and the field tests. Efforts should be made to improve the simulation of field conditions in laboratory procedures before it is possible to make a valid mathematical model which is able to predict dispersion effectiveness under given conditions. Furthermore, the methodology and reproducibility of field tests of dispersant effectiveness should be improved

Abstract
This report reviews 60 research papers focusing on dispersant use in Scandinavian countries over a 10-year period. Some of the topics covered in the review include: attitudes towards dispersants, national regulations on dispersant use, research programs focusing on dispersants, review of current projects, and recommendations for further study

Abstract
In Norway, mechanical recovery has traditionally been the preferred oil spill response technique for the past decades. More recently, the Norwegian Pollution Control Authority (SFT) has opened the door to the consideration of dispersant use in certain oil spill situations. The responsibility for planning and decision for use/non-use of dispersants lies with the oil industry/enterprise itself; their decisions are subject to review and approval by SFT. This is in accordance with the "Principle of Internal Control" on what the Authorities focuses their regulations. The new regulations for use of dispersants in Norway requires well-documented contingency plans for refineries, oil terminals and offshore installations. This change in the attitude to the use of dispersants in Norway is a result of the recent years progress in scientific documentation of dispersant use. Previous paper (Spill Science & Technology Bulletin 5(1) 1999 63) gives an overview of the methodologies developed for oil weathering and dispersibility studies in the laboratory forming the basis for the development of the SINTEF Oil Weathering Model, which has been extensively validated in the field. This paper gives a summary of the main findings from recent years dispersant field trials in the North Sea. This work forms a basis for building up an operational and effective dispersant response for specific Norwegian coastal and offshore locations/regions. Data generated from the experimental field trials have been invaluable for validation and development of numerical models for fate and response assessment of oil spills. Examples in using the quantitative model tool "Oil Spill Contingency and Response" (OSCAR) in contingency planning and Net Environmental Benefit Analyses (NEBA) of oil spill scenarios are given

Abstract
The results of a series of chemical dispersion tests are presented, in which three crude oils (Gullfaks, Statfjord and Arabian heavy), each at 4 states of weathering, have been dispersed at 13°C with two dispersants (Finasol OSR-5 and OSR-12) using three laboratory tests (Warren Spring Rotating Flask WSL test, Institute Francais du Petrole flow test -IFP test and Mackay-Nadeau-Steelman - MNS test). Effectiveness and dispersed oil droplet size distributions in the different test methods have been studied and an attempt has been made to develop correlation or mathematical models of the chemical dispersion phenomena. This mathematical treatment helps to explain the reasons that the tests give different results, but it is concluded that, at present, our understanding of the basic dispersion phenomena is not sufficient to form a basis for a reliable model. Several modelling approaches are discussed in the hope that as further data and insights become available, reliable models may be developed to describe this complex process

Abstract
During the four-year research program ESCOST ('ESSO-SINTEF Coastal Oil Spill Treatment Program'), significant improvements have been made in oil spill combat methods and in tools for use in contingency planning and decision-making during oil spill operations. This paper presents an overview of the main findings obtained with respect to oil weathering and oil spill dispersant treatment during this research program, including: new methodology for systematic investigations of the weathering properties of oils at sea; development of high performance dispersant formulations for weathered and emulsified oils; improvements in dispersant application techniques and applications procedures/strategies; and development of dynamic oil spill simulation model tools for use in designing more optimal and cost-effective oil spill contingency solutions

Abstract
GC and spectrofluorometric methods were used to determine the stability of suspensions of oil and dispersant in seawater over a period of days. Suspensions were found to be effectively stable from days 3 to 15. Adult female Tisbe bulbisetosa were found to tolerate the suspensions in short-term exposures, even though pollutant concentrations were roughly 200 times higher in bioassays than in areas from where the organisms were collected. Results of long-term effects on egg production, number of nauplii, hatching success for third and fourth generations continually exposed to suspensions, were not found to be different from controls