1、Designation: F 2205 07Standard Guide forEcological Considerations for the Use of ChemicalDispersants in Oil Spill Response: Tropical Environments1This standard is issued under the fixed designation F 2205; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers recommendations for use of chemicaldispersants to assist in the
3、control of oil spills and is writtenwith the goal of minimizing the environmental impacts of oilspills. Aesthetic and socioeconomic factors are not considered;although, these and other factors are often important in spillresponse.1.2 Each on-scene commander has available several meansof control or c
4、leanup of spilled oil. In this guide, use ofchemical dispersants should not be considered as a last resortafter other methods have failed. Chemical dispersants shouldbe given equal consideration with other spill countermeasures.1.3 This guide presents general guidelines only. The oil isassumed to be
5、 dispersible and the dispersant to be effective,available, applied correctly, and in compliance with relevantgovernment regulations. Oil, as used in this guide, includescrude oils and fuel oils. Differences between individual dis-persants and to a certain degree, differences between differentoils ar
6、e not considered.1.4 This guide is one of several related to dispersantconsiderations in different environments. The other standardsare listed in Section 2.1.5 This guide applies to marine and estuarine environmentsbut not to freshwater environments.1.6 In making dispersant use decisions, appropriat
7、e govern-ment authorities should be consulted as required by law.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the appl
8、ica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F 2532 Guide for Determining Net Environmental Benefitof Dispersant Use3. Significance and Use3.1 This guide is meant to aid local and regional spillresponse teams who may apply it during response planning a
9、ndspill events.3.2 This guide presents data on the effects of surface oil,dissolved oil and dispersed oil on components of tropicalenvironments. These data can aid in decision-making related tothe use of dispersants to minimize environmental damage fromoil spills.4. General Considerations for Making
10、 Dispersant-UseDecisions4.1 The decision of whether to use or not to use dispersantsin a given spill situation involves trade-offs. Dispersing a slickat one site temporarily introduces more oil into the watercolumn at that site than would be there if a surface slick floatedover it. Therefore, advers
11、e effects on water column organismsmay be increased at that site so that adverse effects can bedecreased at other sites.4.2 Dispersant use is primarily a spill control method, not acleanup method. Such use can give spill response personnelsome control over where the impacts of a spill will occurwhat
12、ever types of impacts they may be. Since some environ-ments are known to be more vulnerable to the longer-lastingimpacts of spilled oil, an acceptable trade-off may be to protectthose environments by dispersing an oil slick in a less sensitiveor less productive environment. In general, the net envir
13、on-mental benefit of dispersant use versus non-use should be1This guide is under the jurisdiction of ASTM Committee F20 on HazardousSubstances and Oil Spill Response and is the direct responsibility of SubcommitteeF20.13 on Treatment.Current edition approved Nov. 1, 2007. Published November 2007. Or
14、iginallyapproved in 2002. Last previous edition approved in 2007 as F 2205 02 (2007).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary
15、page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.evaluated (see Guide F 2532). The net environmental benefit ofa particular countermeasure involves evaluating benefits anddisadvantages of the particular technol
16、ogy being evaluated,versus other cleanup methods or no action, on the habitat orecosystems involved in the area. Environmental benefit analy-sis is best conducted before the spill.4.3 In this guide, environments that are most vulnerable tothe longer-term impacts of oil contamination are identified.P
17、rotection of these environments is recommended as a highpriority, by means of dispersants or other methods.5. The Tropical Environment5.1 Tropical environments encompass many different habi-tats. This guide will cover those habitats that are important interms of decisions to use dispersants. The app
18、lications ofdispersant to open waters and waters of depth greater thanabout 10 metres will not be covered here and is covered byother guides listed in Section 2. Shallow waters and habitatsassociated with mangroves, seagrasses and coral reefs areimportant considerations. Habitats other than those su
19、ch assand beaches, mudflats, cobble beaches and rocky shores maybe common in certain localities but are generally less-sensitive.5.2 Mangrove ecosystems are intertidal forests dominatedby various species of woody halophytes that are commonlycalled mangroves. There are many families and species ofman
20、groves (1-4)3. Mangrove ecosystems occur in tropicallow-energy depositional areas. Mangroves tend to furtherpromote the deposition and recycling of organic and mineralmatter. Their extensive root systems are very important instabilizing intertidal sediments (3). Adult mangroves form thestructural ba
21、sis for the mangrove community in that theyprovide attachment sites for many species of animals andshelter for many others.5.2.1 Mangrove ecosystems contribute to the productivityof tropical marine ecosystems where they play the same butmore important roles as do salt marshes in temperate climates.M
22、angroves are important as nursery areas as well as for thedetritus that they supply to the surrounding communities (3).Much of the worlds fish populations depend on detritus andremineralized nutrients exported from mangrove areas (5).5.2.2 Mangrove forests dominate much of the worldstropical shoreli
23、ne; many are adjacent to tanker routes, oil fieldsand refineries. The low energy characteristic of mangroveforests leads to the entry and retention of oil in these environ-ments.5.3 Coral ReefsCoral reefs are structures created andmaintained by the establishment and growth of hard corals andcorallin
24、e algae. They may be comprised of emergent orsubmergent reefal zones, or a combination of both. Geomor-phically, barrier and fringing reefs protect the insular andcontinental coastlines which they border from erosion. Typi-cally, the coral reef provides habitat for a large variety ofattached plants
25、and epifauna, infauna, mobile invertebrates,and fishes. The large number of economically importantspecies they support make reefs locally important in commer-cial and sport fisheries. The resultant high diversity andabundance of reef associates and the functional and spatialdominance of corals and c
26、oralline algae are the essentialcharacteristics of coral reefs.5.3.1 Coral reefs are circumglobal in the tropics and sub-tropics between the northern and southern hemispheric 18.5Cclimatic isotherms. A majority of coral species and the mostdiverse reefs occur in Indo-West Pacific seas. Tropical West
27、Atlantic and Eastern Pacific reefs are generally less diverse interms of corals and reef associates.5.4 SeagrassesSeagrasses can be found in shallow marineenvironments from the tropics to Polar regions. This guidefocuses on those located in tropical waters. Seagrass beds forma discrete ecosystem tha
28、t traps detritus derived from terrestrialand marine sources, and then exports large quantities of plantand animal materials, including leaf and root fragments,dissolved organic matter, and detritus, to the open sea. Thepresence of an extensive network of roots and rhizomesfacilitates the sediment-bi
29、nding ability of the grass beds; theseagrass leaves effectively retard currents, thus promotingsedimentations of organic and inorganic materials around theplants.5.4.1 Seagrass communities are among the most productiveof natural ecosystems. Seagrass leaf blades support largenumbers of epiphytes whic
30、h can equal the biomass of the grassitself. Major food chains are based upon a variety of epiphytesand associated organisms. Active sulfur, nitrogen, phosphorus,and carbon cycles are maintained through the sediment-plant-water interfaces, and the dense interlacing mat of vegetationprovides ideal cov
31、er for foraging marine fauna as well asshelter and protection for larval and juvenile forms.6. Effects of Oil and Dispersed Oil on Tropical Biota6.1 MangrovesMangroves are primarily impacted by oilby three different routes; through the oiling of the pneumato-phores, or breathing pores typically loca
32、ted on special aerialroots or stems, through oil absorption from the water columnand through oil absorption through the roots from contami-nated soil/sediment and ground water (6-12). Mangroves withoil on pneumatophores may die within about 5 to 7 days,depending on oxygenation conditions at the site
33、 (13-15).Mangroves may die from high concentrations of oil in thewater column (16-18). The third route of oil impact onmangroves, through oil absorption from the soil, is also welldocumented (19-22). Oil in mangrove-dominated sedimentscan cause long-lasting effects and degrades only very slowly(23-2
34、7). Sublethal effects including leaf loss, deformations,and low growth can persist for five years after the spill event(8, 9, 28). Replanting mangroves, a primary restoration methodis successful in soils with reduced hydrocarbon content (29-33). Natural regrowth occurs, but occurs slowly (34-36).Cou
35、ntermeasures which reduce the amount of oil arriving intothe mangrove area are suggested (37-40).6.1.1 Low levels of oil from either dissolved/dispersed oil inthe water column or in the sediments cause a variety ofsub-lethal effects on mangroves, including leaf loss, reducedgrowth of adventitious ro
36、ots, abnormal pneumatophores andmineral imbalance, and slow growth rates (42-45). Studies3The boldface numbers in parentheses refer to a list of references at the end ofthis guide.F2205072show that these effects will persist from 1 year up to 7depending on amount of oil and environmental conditions.
37、6.2 Biota Associated with Mangrove ForestsMangroveforests provide shelter and support for an extensive system ofbiota including algae, crustaceans, and molluscs. Dissolvedand dispersed oil can cause lethality to mangrove biota at levelsas low as 20 ppm and naphthalene as low as 0.4 ppm onprolonged c
38、ontact (44-53). Studies have shown that the abun-dances of species inversely correlated with the apparent oildamage (54). Other studies have shown that the specificnumbers of a given species did not necessarily correlate withoil content (55, 56).6.3 Coral ReefsCorals can be exposed to oil by twomode
39、s, direct oiling and through the uptake of dissolved ordispersed oil. Direct oiling occurs rarely but can result inextensive mortality. The uptake of dissolved and dispersed oilcan result in severe mortality at levels as low as 12 L/L forprolonged exposures (57). Corals are not usually subject tohar
40、mful concentrations of water-borne hydrocarbons by thepassage of a slick overhead and are typically unaffected(58-61). Similarly corals have been shown to reject particles ofoil larger (60 m) than dispersed droplets (62). Corals are,however, particularly susceptible to high concentrations ofdissolve
41、d and dispersed oil and this may lead to long lastingeffects or mortality (44, 45, 49, 63-66 ). Because dispersantsmove oil into the water column, they may increase the effect ofthe oils on corals (5, 41, 67). Exposure of corals to about 20 to50 ppm of dissolved or dispersed oil showed that behavior
42、alreflexes were induced in corals, however depuration was notedwithin a week and recovery within a few weeks (68-70). Somelong-lasting effects of low-level exposure was observed, in-cluding reduced growth and deformation.6.4 Biota Associated with Coral ReefsCoral reefs provideshelter and support for
43、 an extensive system of biota. Prolongedexposure to dissolved and dispersed oil can cause lethality toreef biota at levels as low as 20 ppm (12, 44-49, 52, 53, 71-73). Studies have shown that the abundances of species inverselycorrelated with apparent oil damage (74). Increasing amountsof oil availa
44、bility, such as through the use of dispersants,increases the exposure of organisms to oil (75 and 76).6.5 SeagrassesSeagrasses can be exposed to oil by twomethods, direct oiling and through the uptake of dissolved ordispersed oil. Direct oiling occurs rarely but can result inextensive mortality (17)
45、. The uptake of dissolved and dispersedoil can result in severe mortality at levels as low as 100 g/L(77). Seagrasses are not usually subject to harmful concentra-tions of water-borne hydrocarbons by the passage of a slickoverhead and are typically unaffected (78-80). Seagrasses are,however, particu
46、larly susceptible to high concentrations ofdissolved and dispersed oil and this may lead to long lastingeffects or mortality. The lethal toxicity to seagrasses varies verymuch with species, and is between 75 to 125 ppm in 100 h (81,82). Use of dispersants may increase the exposure of sea-grasses to
47、oil (83, 84).6.6 Biota Associated with SeagrassesSeagrasses provideshelter and nutrients for an extensive system of biota (85, 86).Dissolved and dispersed oil can cause lethality to these biota atlevels as low as 20 ppm (12, 44-49, 52, 53, 71-73 ). Increasingamounts of oil availability, such as thro
48、ugh the use of dispers-ants, increase the exposure to organisms (75).7. Recommendations7.1 Dispersant use decisions must be based on the netenvironmental benefit analysis of use versus non-use of dis-persants.7.2 Dispersant use decisions should include consideration ofthe proximity of the dispersant
49、 application to sensitive marineenvironments including mangrove forests, seagrasses and cor-als.7.3 An important consideration is the flushing rate of waterin the mangrove, seagrass and coral areas. If the flushing rateis rapid, dissolved and dispersed oil will have minimal effects.7.4 In many jurisdictions there are regulatory limitations inwater depth (3 to 30 m) that dispersants can be applied. Theselimitations shall be followed.7.5 Dispersants are best applied in deep waters and not indirect proximity to mangroves, seagrasses and corals.7.6 Chemical dispersion should
