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This paper examines the costs of various cleanup techniques, drawing mainly on information from recent oil spills from ships. Analyses of the costs for dispersant application and for the use of offshore mechanical recovery equipment are compared in relation to their effectiveness and scope for reducing shoreline cleanup costs and damage from oil pollution. Spill size, oil type, coastline character, and the extent of pollution all contribute to the observed differences in shoreline cleanup and disposal costs. The influence of these factors is evaluated and criteria are proposed for selecting the most appropriate cleanup response to suit the circumstancees of a particular oil spill. On occasions, a response at sea is both necessary and worthwhile, but for most spills shoreline cleanup, including protection of sensitive resources, is likely to be the most cost-effective option.

Preface xv CHAPTER 1 Introduction 1.1 Background 1.2 The role of IMO and the progress of Marine Pollution Legislation 1.2.1 International Convention for the Prevention of Pollution of the Sea by Oil, 1954 1.2.2 MARPOL 73178 1.3 Oil Sources and Marine Transportation for Hydrocarbons 1.4 Operational Discharges at Sea 1.4.1 Tankers 1.4.2 Cargo Ships and Tankers 1.4.3 Other Operational Discharges 1.5 Fate and Environmental Impact of Oil Discharges at Sea 1.6 Scope of the Book References CHAPTER 2 Oil pollution control and international legislation 17 2.1 VII 4.3 Shipboard Installation of Monitor Systems 89 4.3.1 Ballast Monitors 89 4.3.2 Bilge Monitor 92 4.4 Conclusions 93 References 96 CHAPTER 5 Problems of testing oil content monitors to the MARPOL 73/78 specifications 97 5.1 8.2.2 'Test Specification' (from Part II of the Annex to A.393(X)) 8.2.3 'Installation Requirements' (Part II of the Annex to A.393(X)) Resolution A.444(XI) The Test Rig 8.4.1 Capacity 8.4.2 Layout of Test Rig 8.4.3 Test Equipment 8.4.4 Other Test Facilities References Technical requirements of the IMO international performance and test specification concerning oily water separators and process units

Laboratory tests can demonstrate the effectiveness of dispersants relatively easily but it is far more difficult to assess effectiveness in field conditions. In many oil spills, timely application of dispersants is the best approach. It is therefore necessary to study their use in field trials and actual incidents to see what lessons can be learned about the amounts used relative to the amount of oil spilled, types of oil on which dispersants are relatively effective, methods of application, the period after release into the sea during which dispersants remain effective, and the influence of sea conditions and temperatures. This paper discusses these questions, reviewing published data on the performance of dispersants infield trials and in actual oil spills in which staff of the International Tanker Owners Pollution Federation Ltd. have been involved in recent years. Recommendations are made regarding further work in the laboratory and field that appears necessary to determine the conditions under which dispersants are likely to be most effective.

This paper describes experiments conducted with undiluted concentrate dispersants both in the laboratory and at sea which show that oil may be dispersed without the addition of artificial agitation. A description is given of trials over airfields, in which the appropriate droplet size was determined so that virtually all of the liquid discharged from the plane actually reaches the ground/sea surface. Experimental slicks were then laid at sea and the methods are described. These were treated by aircraft using the technique developed over the airfields. Results are presented on fresh crude oil (Kuwait, Ekofisk), topped Kuwait, and topped Kuwait water-in-oil emulsion. Experiments and results obtained with a Piper Pawnee and a DC-4 are included. Information is also presented on the logistics of aircraft use in spills offshore and close to shore with a view to giving as precise an evaluation as possible of the overall feasibility of aircraft dispersant operations.