1、 lMO/FAO GUIDANCE ON MANAGING SEAFOOD SAFETY DURING AND AFTER OIL SPILLS INTERNATIONAL MARITIME ORGANIZATION London, 2002 I First published in 2002 by the INTERNATIONAL MARITIME ORGANIZATION 4 Albert Embankment, London SE1 7SR Printed by the International Maritime Organization, London 2 4 6 8 10 9 7
2、 5 3 1 ISBN 92-801-5147-9 IMO PUBLICATION I Sales number: 1590E I Copyright 0 IMO 2002 All rights reserved. No part of this publication may be produced, stored in a retrieval system or transmitted in any form or by any means, electronic, electrostatic, magnetic tape, mechanical, photocopying or othe
3、rwise, without prior permission in writing from the International Maritime Organization. Preface 1 At its forty-first session, the Marine Environment Protection Committee (MEPC) tasked the OPRC Working Group to develop a guidance document for fisheries management during and after an oil spill incide
4、nt. Dr. Tosh Moller, Technical Team Manager of the International Tanker Owners Pollution Federation Ltd. (ITOPF), prepared the draft guidance document and submitted it at MEPC 42. Following the review and comments from members of the OPRC Working Group and the Fisheries Department of the Food and Ag
5、riculture Organization of the United Nations (FAO), a consolidated draft version was submitted by ITOPF at MEPC 43. Further review on the guidance document was made by Australia and the United States and subsequently by FAO, which also agreed to a joint IMO/FAO publication. At MEPC 45, the revised g
6、uidance document was approved by the OPRC Working Group for a joint IMO/ FAO publication. The Committee, at its forty-sixth session, approved the iii 1 2 3 4 5 Contents Introduction . Oil spill impact on seafood resources 2.1 Effects on marine life 2.2 Fishing and aquaculture activities 2.3 Tainting
7、 2.4 Public health concerns Oil spill response options . 3.1 Protection and clean-up techniques . 3.2 Sensory testing . 3.3 Chemical analysis . 3.4 Costs and compensation . Management strategies for protecting seafood resources 4.1 General considerations . 4.2 Fishing and aquaculture procedures 4.3
8、Fishing and harvesting restrictions Conclusions and recommendations References and further reading Page 1 3 3 5 7 7 10 10 11 12 13 15 15 16 17 19 20 Previous page V is blank 1 Introduction 1.1 Fishing is important in all maritime nations and many oil spills cause damage to subsistence, recreational
9、and commercial fishing activity. Aquaculture enterprises have become widely established, thereby increasing the sensitivity of many coastal areas to oil pollution impact. Increased public awareness and heightened food quality and safety standards have meant that even small oil spills can cause a lar
10、ge impact and generate strong political interest. 1.2 Oil pollution effects take a variety of forms. Animals and plants may be killed as a result of oil smothering and toxicity. Catches and cultivated stock may become physically contaminated or may acquire an objectionable oily taste known as tainti
11、ng. Fishing and cultivation gear may be oiled, leading to the risk of catches or stock becoming contaminated or fishing being halted until gear is cleaned or replaced. The handling of seafood products in bulk means that it is seldom practical to locate and remove the oiled specimens. Storage of fish
12、ing nets and boats (Indonesia) 1.3 Fishermen and aquaculture operators are often in the front line of oil spill impact, but equipment suppliers, transporters, wholesalers and others are also involved in the process of bringing seafood produce to the market. Government authorities have a duty to prot
13、ect public health and ensure that seafood products reaching the consumer are safe and palatable. A number of management strategies are available to prevent or minimize oil pollution impact on fishing and 1 aquaculture activity. Fishing and harvesting restrictions can be imposed to prevent contaminat
14、ion of fishing gear and to protect consumers and markets. Such measures also provide time for evaluating risks and for organisms and their habitat to recover from oil contamination. Seine net fishing (Venezuela) 1.4 The purpose of this Guidance is to identify the various problems that can arise in t
15、he event of an oil spill and to describe the remedies available. The information is aimed primarily at spill responders and managers with responsibilities for protecting public health, as well as those in the fisheries sector suffering economic loss and consumers concerned about the safety and quali
16、ty of seafood. Interested parties are encouraged to share experience gained in managing fishery resources during and after oil spills. persons acting to clean up an oil spill 2 2 Oil spill impact on seafood resources 2.1 Effects on marine life 2.1.1 The impact of an oil spill on marine life depends
17、largely on its geographical location and extension, the physical and chemical characteristics of the oil and the way these change with time, through a process known collectively as weathering. The main physical processes which act on the oil during the course of a spill are evaporation, natural disp
18、ersion and, to a lesser extent, sedimentation. Specific gravity, viscosity, chemical composition and toxicity of the pollutant and the way they change with time tend to determine the degree of oil exposure for seafood organisms. The prevailing weather and sea conditions will determine the movement o
19、f spilled oil. Clean- up activities such as the use of chemicals or aggressive washing techniques can also affect the fate of oil. Thus, a variety of factors combine to define the character of a particular oil spill and the fate of sensitive resources in its path. 2.1.2 Adult free-swimming fish, squ
20、id, shrimp and wild stocks of other commercially important marine animals and plants in open waters seldom suffer direct harm from oil spill exposure. This is because only Free-swimming marine species, which include crustaceans such as lobsters and shrimps, could suffer more from oil spill exposure
21、when in shallow intertidal zone than in open waters. 3 rarely will oil concentrations in these waters reach sufficient levels to cause tainting or mortality. The greatest impact is found on shorelines and shallow waters where animals and plants may be physically coated and smothered by oil or expose
22、d directly to toxic components in the oil. Edible seaweeds, and sea urchins, oysters, mussels and clams are examples of shoreline seafood species that are especially sensitive to smothering and oil toxicity, respectively. 2.1.3 Apart from direct effects, oil may cause more subtle longer-term damage
23、to behaviour, feeding, growth, or reproductive functions as well as survival of larval or juvenile forms. It is a complex task to isolate such sublethal pollution effects from the influence of numerous other factors. 2.1.4 Damage may also result from measures taken to combat an oil spill. Animals an
24、d plants which might normally be unaffected by floating oil can become tainted through exposure to oil droplets suspended in the water column if chemical dispersants are used unwisely. For this reason, as a general guide, dispersants should not be used close to aquaculture facilities or spawning gro
25、unds and nursery areas. Stripping oiled seaweed from rocks and indiscriminate hot water washing are further examples of aggressive techniques that can affect commercially exploited species and delay natural recovery. Aerial view of oyster cultivation racks exposed at low tide (France) physical coati
26、ng by oil 4 2.2 Fishing and aquaculture activities 2.2.1 Oil can foul the boats and gear used for catching and cultivating commercial species. Flotation equipment, lift nets, cast nets, and fixed traps extending above the sea surface are more likely to become contaminated by floating oil, whereas li
27、nes, dredges, bottom trawls and the submerged parts of cultivation facilities are usually well protected, provided they are not lifted through an oily sea surface or affected by sunken oil. 2.2.2 Seaweeds, shellfish and cultivated animals kept in cages or tanks are usually unable to avoid contact wi
28、th oil contaminants in the water and the presence of oil pollutants may significantly add to the stresses already imposed by keeping animals in artificial conditions. Fish farming facilities may become physically coated by floating oil and unless they are rapidly cleaned they may act as a longer-ter
29、m source of stock re-con tam i na tion. 2.2.3 There are many complex influences on the health of cultivated organisms and observed effects may be the result of a combination of Seawater intake pipes supplying an onshore cultivation facility (South Korea) 5 factors. If, for example, the stocking dens
30、ity or the water temperature in a fish farm is unusually high, there is a greater risk of mortality, disease or growth retardation occurring as a result of oil contamina- tion. 2.2.4 The cultivation of seaweed, fish, crustaceans, molluscs, echino- derms and sea squirts frequently involves the use of
31、 onshore tanks to rear the young to marketable size, or to a size and age suitable for transfer to the sea. Such facilities are usually supplied with clean seawater drawn through intakes located below the low water mark. The intakes may occasionally be under threat from sunken oil or dispersed oil d
32、roplets, which may lead to contamination of pipework and tanks and the loss of cultivated stock. In many tropical areas animals are cultivated in coastal ponds, lagoons and other enclosures supplied with seawater by tidal action through sluice gates and hence are particularly susceptible to oil spil
33、ls. 2.2.5 Fishing and seafood cultivation are not always pursued throughout the year and seasonal differences in sensitivity to oil spills can therefore occur. For example, most seaweeds grown in Asia are harvested in the spring or early summer and the next generation is not planted out until early
34、autumn. The collection of wild seed, or the rearing of larvae in onshore tanks supplied with water piped from the sea are other examples of seasonal activity. Indoor cultivation tanks fitted with aerators 6 2.3 Tainting 2.3.1 The contamination of seafood can usually be detected as a petroleum taste,
35、 or taint. Public confidence in seafood products can quickly erode as a result of suspect, or actually contaminated, products reaching the market. Filter-feeding animals such as bivalve molluscs are particularly vulnerable to tainting since they may easily ingest dispersed oil droplets and oiled par
36、ticles suspended in the water column. Animals with a high fat content have a greater tendency to accumulate and retain petroleum hydrocarbons in their tissues. 2.3.2 A taint is commonly defined as an odour or flavour that is foreign to a food product (ISO, 1992). Background concentrations of oil in
37、water, sediment and tissues are highly variable and both the degree of taint which may result and consumer tolerance levels for taint are different for different seafood products, communities and markets. The presence and persistence of taint will depend mainly on the type and fate of oil, the speci
38、es affected, the extent of exposure, hydrographic conditions and temperature. Tainting of living tissue is reversible but, whereas the uptake of oil taint is frequently rapid, the depuration process whereby contaminants are metabolized and eliminated from the organism is slower. 2.3.3 The concentrat
39、ions of hydrocarbons at which tainting occurs are very low. Some of the chemical components in crude oils and oil derivatives with the potential to cause tainting have been identified, but many are unknown and no reliable threshold concentrations for petroleum-derived tainting agents have been estab
40、lished. Hence it is not possible to determine by chemical analysis alone whether a product is tainted or not. However, the presence or absence of taint can be determined quickly and reliably by sensory testing, when a trained panel and sound testing protocols are employed. Sensory testing is further
41、 described in section 3.2. 2.4 Public health concerns 2.4.1 The occurrence of contamination in seafood organisms or products following a major spill has potentially damaging implications for marketing and can lead to public health directives being invoked because of the presence of known carcinogeni
42、c compounds in petroleum products. The aromatic fractions of oil contain the most toxic compounds, and amongst these it is the 3- to 7-ring polycyclic aromatic hydrocarbons (PAH) that command greatest attention. 2.4.2 The input of potentially carcinogenic PAH stems largely from combustion sources an
43、d petroleum and, for the human population, exposure to PAH is primarily from food. However, in common with removal of substances from tissues by metabolic processes 7 other potentially carcinogenic pollutants, it is not possible to define a concentration threshold of potential carcinogens in seafood
44、 products that represents a risk-free intake for humans. Furthermore, a wide variety of smoked food, leafy vegetables and other dietary compo- nents also contain the same PAH compounds. The detailed composi- tion of the diet determines which food items might be major contributors of PAH for individu
45、al consumers. It is important to recognize that different regions and ethnic groups have varying levels of seafood in their diets. Fish market produce (Turkey) 2.4.3 Generally, PAH levels in foods are not subject to legislative limits, although limits exist for some compounds in drinking water. The
46、risk to an individual or community from oil-spill-derived carcinogens should be assessed in the context of the overall exposure from all potential sources, which is subject to many variables. From a general risk evaluation of the amount, frequency and duration of PAH exposure following oil spills, m
47、ost studies have led to the conclusion that oil-spill-derived PAH contamination of seafood is not a significant threat to public health (GESAMP, 1993; EPA, 1997). However, it is important to note that whilst toxicologists have assessed the threat to public health as negligible, it may be difficult t
48、o convince local users, fish buyers and consumers in general, especially when there is an option of buying seafood from other locations. 8 2.4.4 A further complication for food safety and quality controllers is the fact that a seafood diet is inherently nutritious and rich in protein and vitamins. R
49、estrictions on seafood intake can cause consumption patterns to shift towards less healthy diets. Seafood safety and quality is also affected by other forms of contamination, such as heavy metals, algal toxins, pathogenic bacteria and viruses. The potential impact of an oil spill on public health must be viewed in a wider context in order to identify and implement appropriate strategies. 9 3 Oil spill response options 3.1 Protection and clean-up techniques 3.1.1 Booms and other physical barriers can sometimes be used to protect fixed fishin
