ABSTRACT. A series of experiments was conducted to evaluate selected countermeasures for the cleanup of oil on remote beaches. These experiments formed part of the Baffin Island Oil Spill (BIOS) Project, which was conducted at Cape Hatt, N.W.T., between 1980 and 1983. An isolated lagoon was selected with a series of segregated bays that could be used for discrete experiments with control and countermeasure plots. Intertidal control plots were established in 1980 at an exposed site and at a relatively sheltered location. The oil on the exposed intertidal control plot was removed rapidly by natural processes so that subsequent attention was focused on low wave energy sites. Countermeasure experiments were conducted in 1981 in the intertidal zone at a relatively sheltered site and in 1982 in the intertidal and backshore zones at a very sheltered beach. At each of these two locations, control and countermeasure plots were duplicated using an aged Lagomedio crude oil and a water in aged Lagomedio emulsion. Countermeasures were selected for testing on the basis of existing experimental or practical knowledge and the applicability to remote or arctic beach environments. The selected techniques were incendiary combustion, mechanical mixing, chemical dispersion, solidifying and low-pressure flushing.Samples of surface and subsurface sediments were collected throughout the experiments for total hydrocarbon and GUMS analysis. Two chemical dispersants (BP 1 lOOX and Corexit 7664) were effective on the relatively sheltered beach but neither was effective on the very sheltered beach due to the lack of wave energy to agitate or to redistribute the oiYdispersant mixture. The mechanical mixing of backshore sediments accelerated the removal of surface oil but increased subsurface hydrocarbon concentrations. Low-pressure flushing on the very sheltered fine-grained beach did not reduce surface hydrocarbon concentrations and resulted in higher oil in sediment concentrations when compared to an adjacent control plot. The solidifying agent was an effective method for encapsulating oiled beach sediments. Over a five-to six-week period the control plot data indicates that rates of natural cleaning resulted in similar total hydrocarbon values when compared to the Countermeasure plots. However, these results must be considered in the context of edge effects and dispersion that are a function of using small (10 m X 2 m) intertidal plots. Such plots represent only patchy contamination. AS the experimental concept was aimed primarily at the cleanup of heavily contaminated beaches, the primary evaluation of the countermeasures relates to data obtained only from the first week of each experiment. Neither the incendiary device nor the low-pressure flushing techniques proved to be effective, whereas over this short period mixing and chemical dispersion demonstrated a potential to mitigate the effects of beach contamination or to accelerate the removal of stranded oil. hydrocarbures et pour l'analyse par CG/SM. Deux agents de dispersion chimiques...

Research studies were conducted to evaluate the use of selected earthmoving equipment in oil-contaminated beach-restoration operations and to determine the cost and effectiveness of such equipment Specifically, the objectives were to:Determine modifications and cost required to improve the capacity of selected equipment.Develop optimum operating procedures for each method.Determine, through field testing, the operating cost of each method evaluated. These objectives were accomplished in two phases. Phase I: reviewed procedures utilized in previous beach-restoration operations, plus surveyed and evaluated commercially available earthmoving equipment. Phase II: conducted full-scale tests to demonstrate the restoration procedures developed and to determine the efficiency with which each procedure/equipment item collects oil-contaminated material The flexibility and performance characteristics of the equipment were tested under a variety of beach conditions. The oil removal effectiveness was greater than 98% for all restoration procedures. The highest effectiveness was achieved using the motorized grader and motorized elevating scraper working in combination. The tracked front end loaders were least effective. On beaches possessing low shear strength, flotation tires or steel-belted half-tracks on the motorized grader and a non-self-propelled elevating scraper with a tracked prime mover should be used. Conveyor-screening systems can be effectively utilized to load oil-contaminated material into trucks for transport to disposal areas, separate oil-sand pellets from clean sand, and partially separate oil-contaminated debris (i.e., straw, kelp, seaweed) from oil-contaminated sand The beach-restoration operations evaluated in this study were successfully utilized in the restoration of oil-contaminated beaches resulting from the recent San Francisco Bay oil spill incident. This study was conducted in fulfillment of Contract No. 14-12-811 between The Federal Water Quality Office, and The URS Research Company.

Field experiments have been conducted on arctic beaches to assess the effectiveness of dispersants for the cleanup of stranded oil. The application of two commercially available chemical dispersants to aged and emulsified oil plots, in the intertidal zone on a semi-sheltered beach, resulted in a significant reduction of oil loadings immediately following the experiment as compared to loadings on adjacent intertidal control plots. The use of dispersants may, therefore, be of some value in mitigation of the potential adverse effects of oil immediately following stranding. In the semi-sheltered arctic environment in which the 1981 experiments were conducted (fetch up to 100 km; two-month open-water season), natural reworking of the oiled intertidal control plots over a 40-day period was effective in removing approximately 85 to 95% of the original oil loading. Further experiments in 1982 replicated the 1981 study in a more sheltered location, with a fetch area of less than 2 km, and indicate that the use of dispersants was not effective in this very low-energy environment. The conclusions drawn from this arctic experiment have a direct relevance to other coastal environments in lower latitudes.

Terrain conductivity is a geophysical technique which, by inducing current into the ground, can measure the conductivity of subsurface soils and interstitial waters. Hydrocarbons are not conductive materials and, because the surrounding lithology behaves to a certain extent as a conductor, the presence of pooled hydrocarbons floating on groundwater can be determined by the use of a terrain conductivity survey. Two case histories are presented in which terrain conductivity measurements were used to determine the extent and thickness of subsurface hydrocarbon plumes.

Experiments associated with the oiling of beaches in an arctic environment show that fetch and wave-energy conditions at the shoreline are primary factors in determining the persistence of stranded oil. Five intertidal sections of coast were oiled, each of which differed in terms of shoreline exposure and fetch. The oil loadings of the test beaches that were oiled artificially were in the same range as those from an adjacent nearshore spill, so that the experimental results can be assumed to replicate real-world oiling conditions. On the most exposed beach (fetch 90 kilometers) all oil was removed naturally after 80 days of exposure to open-water conditions. At a semi-exposed location, 85 to 95 percent of the oil was removed within 40 days, and at the most sheltered test sites (fetch less than 2 km) between 5 and 30 percent of the oil remained after an observation period of 160 open-water days. Data collection to determine fates of oil at the different sites over a four-year period is continuing. In this relatively low-energy wave climate environment, with an open-water season of about 60 days, most exposed beaches would be cleaned naturally to levels less than 500 milligrams/kilogram within 100 days, but where the fetch is less than 10 to 25 km the expected persistence of oil stranded in the intertidal zone could be greater than 10 years.