IMO 649E-1997 FIELD GUIDE FOR OIL SPILL RESPONSE IN TROPICAL WATERS.pdf

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1、FIELD GUIDE FOR OIL SPILL RESPONSE IN TROPICAL WATERS INTERNATIONAL MARITIME ORGANIZATION FIELD GUIDE FOR OIL SPILL RESPONSE IN TROPICAL WATERS INTERNATIONAL MARITI ME ORGANIZATION London, 1997 Published by the INTERNATIONAL MARITIME ORGANIZATION 4 Albert Embankment, London SE1 7SR Printed in the Un

2、ited Kingdom by Artigraf, Greenford, Middlesex 2 4 6 8 10 9 7 5 3 1 ISBN 92-801-14204 IMO PUBLICATION I Sales number: IMO-649E I Copynght 0 IMO 1997 All rights reserved. No part of this publication may, for sales purposes, be produced, stored in a retrieval system or transmitted in any form or by an

3、y means, electronic, electrostatic, magnetic tape, mechanical, photocopying or otherwise, without prior permission in writingfrom the International Maritime Organization. ACKNOWLEDGEMENTS The Secretariat would like to express its gratitude to the individuals and. organizations who assisted with the

4、preparation of this field guide, and to those whose publications provided useful information. Special thanks go to: Dr. Jenifer Baker for preparing the final text and for providing photographs; the International Petroleum Industry Environmental Conservation Association (IPIECA) and the Swedish Inter

5、national Development Agency for funding the preparation of this field guide; the Australian Institute for Petroleum and the Australian Marine Oil Spill Centre for assisting in the development of the first draft text; IPIECA and the International Tanker Owners Pollution Federation, whose publications

6、 provided useful information for this guide; Dr. F. Dippter for providing photographs 10 and 11; and the Australian Maritime Safety Authority for providing the photograph for the front cover. Cover photograph: M/V Peacock aground on Piper Reef, Great Barrier Reef, Australia. Preface A vast number of

7、 different oil spill response guidelines are available today. However, these tend to focus on habitats and conditions found in temperate and arctic zones. This field guide is directed to those who have to respond to oil spills in tropical marine waters and to Governments involved in developing respo

8、nse strategies for these regions. It aims to provide information on the response measures to be taken and those to be avoided for different types of tropical habitats. Background information is included on the fate of spilled oil, characteristics of the different marine habitats, and spill response

9、techniques. The principles of spill response give in this guide are based on case histories and experiments reported in the scientific literature. There is no intention to provided rigid rules because each spill has its own unique features and responders need to maintain flexibility. This field guid

10、e should be read in conjunction with IMO (1988), Manual on Oil Pollution, Section IV: Combating Oil Spills; IMO/UNEP (1995), IMO/UNEP Guidelines on Oil Spill Dispersant Application including Environmental Considerations; IPIECA (1992), Biological Impacts of Oil Pollution: Coral Reefs, IPIECA Report

11、Series, Volume 3; IPIECA (1993a), Biological Impacts of Oil Pollution: Mangroves, IPIECA Report Series, Volume 4; and IPIECA (1994), Biological Impacts of Oil Pollution: Saltmarshes, lPIECA Report Series, Volume 6. The first draft of the field guide was prepared by an IMO consultant with assistance

12、from the Australian Institute for Petroleum and the Australian Marine Oil Spill Centre, and funding from the Swedish International Development Agency. This first draft was presented to the thirty-fourth session of the Marine Environment Protection Committee (MEPC) for consideration by the Oil Pollut

13、ion Preparedness, Response and Co-operation (OPRC) Working Group. The Working Group noted that there had been a number of recent relevant publications which should be included in the text and agreed with the proposal of the Secretariat that it review and revise, as appropriate, the draft text and ci

14、rculate for consideration at the thirty-fifth session of the MEPC a succinct summary which would form the basis of development of the field guide. Following the decision taken by the OPRC Working Group, the Secretariat submitted a new draft text for consideration by the Working Group at the thirty-f

15、ifth session of the MEPC. The Working Group endorsed the approach taken by the new draft and noted that additional development of certain topics and some minor corrections were required. The International Petroleum Industry Environmental Con- servation Association (IPIECA) offered to take the lead i

16、n the development of this guide and 1PIECAs Environmental Adviser, I . 111 Preface Dr. Jenifer Baker, provided a revised draft version for the consideration of the Working Group at the thirty-seventh session of the MEPC. At this session the Committee approved its publication and authorized the Secre

17、tariat, in conjunction with IPIECA, to make necessary editorial corrections and alterations prior to publication. iv Contents Introduction Section 1 - Initial procedures to be considered 1.1 Safety . . 1.2 1.3 Alerting the appropriate autho . 1.4 1.5 1.6 Spill control operations . . . . . . . Predic

18、ting how the oil will change in the marine environment . . . . . . . Tracking oil-slick movement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the response priorities . . . . . . . . . . . . . . . . . . . . . . . . . . Section 2 - Response actions for differ

19、ent habitats and organisms . . . . . . . . . . . . . . . . . . . . 2.1 Open water 2.3 Mangroves . . 1 3 3 3 4 4 10 11 15 16 18 20 Illustrations 21-30 2.4 Saltmarshes . , . . . , . . . . . . . . . . . . . . . . . . . . . 2.5 Seagrass beds . 2.10 Birds . 2.11 Mammals . 2.12 Fisheries an Section 3 - Eq

20、uipment and materials used for response actions . . 3.2 Booms . 3.3 Dispersants . . . . . . . . . . . . . . . . . Section 4 .- References and further reading V 33 35 37 39 41 43 43 45 45 47 47 47 49 50 51 51 52 52 53 Introduction Many tropical regions are at risk from oil spills, for a number of rea

21、sons. These include offshore oil production (often in relatively shallow waters), the proximity of important shipping routes, and the presence of coastal installations which handle oil (e.g., refineries). Many tropical nations rely on the sea for food and water. The sea and coastal environments are

22、important economically, through fishing (both artisanal and industrial), aquaculture and tourism. Clean seawater supplies are essential for desalination plants, some industrial processes, aquaculture ponds, and salt production. Tropical regions contain unique ecosystems with a high diversity of orga

23、nisms. Many of these ecosystems are known to be sensitive to oil spills, which can have detrimental effects on both the ecology and the economy. Protection and clean-up measures following spills are therefore important, but can be difficult because of the remoteness of many of the areas of concern.

24、Oil spill response in the tropics differs from that in temperate or cold regions not only because the tropics contain unique habitats but also because the behaviour of oil is different in warm waters, in ways highlighted in this guide. 1 Section 1 Initial procedures to be considered The following in

25、itial procedures must be considered when preparing contingency plans to deal with an oil pollution incident. In practice, many of these activities will proceed simultaneously after a spill: rn take appropriate safety measures; rn alert responsible authorities; rn rn rn take measures to control the s

26、pill; predict how the slick will change with time, in order to choose the most appropriate response; track the slick movement in order to find out which areas are under imminent threat from the oil; determine the response priorities and appropriate strategies. 1.1 Safety Safety is of prime importanc

27、e and precautions have to be considered at all times. In the tropics the hazard of vapours is increased and as a con- sequence the risk of explosions and the presence of toxic gases is high. Gasoline, some crude oils and other flammable oils (flashpoint below 38C) may present fire or explosion hazar

28、ds if spilled. Naked lights or other possible sources of ignition must be avoided. Radio and radar equipment may constitute a hazard. The oil and atmosphere should be sampled at regular intervals to check flashpoint and flammable gas concentration until the light compounds have evaporated and the fl

29、ashpoint of the oil is well above 60C (IMO, 1988). The safety of any passing vessels should be taken into consideration and vessels not complying with tanker regulations should operate downwind at safe distances from fire or explosion hazards (IMO, 1988). If hydrogen sulphide is present, the area sh

30、ould be evacuated immediately and expert help should be called for. Hydrogen sulphide is a highly toxic, colourless gas with an odour of rotten eggs; however, the sense of smell should not be used to detect it since in high concentrations it causes olfactory fatigue. Persons handling fuel or spill-t

31、reatment chemicals must observe any handling instructions given by the manufacturer concerned. In the absence of such instructions, prolonged skin contact must be avoided and protective clothing, gloves and goggles should be worn. 1.2 Spill control operations Every effort should be made to stop or r

32、educe the discharge. For further detail refer to the Manual on Oil Pollution, Section IV: Combating Oil Spills (IMO, 1988). As far as possible, appropriate clean-up techniques on water should be employed while the spill area is still small and before it reaches sensitive areas and/or amenities (refe

33、r to section 2.1). If there is 3 Previous page is blank Section 1 - Initial procedures to be considered any danger of oil reaching sensitive areas or if the spill occurs near such areas, then appropriate protection/clean-up actions should be taken (refer to section 2). Rapid response is essential si

34、nce most oils tend to spread fast and the slick tends to decrease in average thickness, which makes any recovery process difficult; also the efficiency of chemical dispersants decreases rapidly as the oil weathers. Most spills occur in coastal waters and require very fast response actions in order t

35、o prevent sensitive areas and amenities from being contaminated with oil. 1.3 Alerting the appropriate authorities The size of the spill and its location determine which authorities should be alerted. The following may be involved: rn rn authorities responsible for oil spill response actions; author

36、ities responsible for informing other States who may be affected, or any existing regional agreements or organizations, and IMO (in case of severe pollution incidents); authorities responsible for transmission and processing of urgent reports regarding oil spills; authorities responsible for request

37、ing assistance on behalf of the State; authorities responsible for rendering assistance on behalf of the State if requested. rn rn 1.4 Predicting how the oil will change in the marine environment It is important to predict the changes which might occur to the oil once it is spilled. These affect the

38、 oils persistence and its effect on the environment: and have a bearing on the response actions. In some cases no response may be required if the oil can be predicted to dissipate naturally before it reaches sensitive areas, and if these predictions are confirmed by repeated surveillance. Oil spille

39、d at sea will undergo a number of changes due to weathering processes such as spreading, evaporation, dispersion, emulsification, dissolution, oxidation, sedimentation, and biodegrada- tion. The way these factors interact to alter the behaviour and character of oil is illustrated in figure 1. The oi

40、l will eventually be assimilated by the marine environment. However, the rate at which this will occur depends on the chemical and physical properties of the oil, the amount of oil spilled, the prevailing climatic and sea conditions, whether the oil remains at sea or is washed on shore, and the type

41、 of shore it is washed onto. In order to gain some insight into how different oils are likely to behave, the changes which may occur to the oils as well as the individual weathering processes are described with emphasis on tropical waters. It is essential to know this since the response techniques n

42、eed to be modified as the oil weathers. 4 Section 1 - Initial procedures to be considered 1 Hrs 1 10 Time Evaporation 100 1000 10000 Mousse+Tar balls Emulsification - Emulsification Dispersion I I Biodegradation i Adsorption onto sediment Figure 1: Processes involved in the weathering of oil on the

43、sea, and the approximate duration over which they occur 1.4.1 Physical properties of oil The main physical properties which will affect the behaviour of oil at sea are specific gravity, distillation characteristics, viscosity and pour point (ITOPF, 1986). Because the distillation characteristics, vi

44、scosity and pour point are affected by temperature, an oil spill will behave differently in tropical regions than it will under cooler conditions. 5 Section 1 - Initial procedures to be considered Specific gratity Oils can be classified according to their specific gravity (density in relation to pur

45、e water). The specific gravity (SG) of crude oils and petroleum products is sometimes expressed in terms of API gravity in accordance with the formula below. The lower the SG of the oil the higher the API gravity, and vice versa. 141.5 131 API gravity = - - SG The SG dictates the buoyancy of an oil

46、on water and influences spreading and natural dispersion (IMO, 1988). Most oils are lighter than water and have specific gravities below 1.0. Oils tend to be more buoyant in tropical regions because the density of seawater decreases by 0.25% with every 10C rise in temperature, whereas the density of

47、 oil decreases by 0.5% (ITOPF, 1986). Oils with low SG (high API gravity) tend to be free flowing (low viscosity), have a high proportion of volatile compounds, and low flashpoints and pour points. Conversely, oils with high SG (low API gravity) tend to have a high viscosity, a low proportion of vbl

48、atile compounds, and high flashpoints and pour points. Although this is a general trend, the properties of oils with high wax or asphaltene content cannot be determined solely by their API gravity. Oils having low SG tend to evaporate rapidly, especially in tropical regions, losing a significant pro

49、portion of their volume in the process. The loss by evaporation is reduced if water-in-oil emulsions are formed; however, most evaporation normally occurs before stable emulsions are formed in tropical regions. The exceptions are oils with high wax or asphaltene content, which may form stable emulsions in tropical waters before the volatile compounds have had time to evaporate. I Viscosity The viscosity of an oil is its resistance to flow: the higher the viscosity, the lower the rate of flow. The viscosity of an oil decreases with increasing temperatures. Thus oils spilled in tropical wa