1、Designation: F2205 07 (Reapproved 2013)Standard Guide forEcological Considerations for the Use of ChemicalDispersants in Oil Spill Response: Tropical Environments1This standard is issued under the fixed designation F2205; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers recommendations for use of chemicaldispersants to
3、 assist in the 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 means
4、of control or cleanup 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
5、isassumed to be 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 disper-sants and to a certain degree, differences between d
6、ifferent oilsare 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 decisi
7、ons, appropriate 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 det
8、ermine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F2532 Guide for Determining Net Environmental Benefit ofDispersant Use3. Significance and Use3.1 This guide is meant to aid local and regional spillresponse teams who may apply it during respo
9、nse planning andspill 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 Considerati
10、ons for Making 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. The
11、refore, adverse 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
12、will occurwhatever 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,
13、 the net environ-mental benefit of dispersant use versus non-use should beevaluated (see Guide F2532). The net environmental benefit ofa particular countermeasure involves evaluating benefits anddisadvantages of the particular technology being evaluated,versus other cleanup methods or no action, on
14、the habitat or1This 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 April 1, 2013. Published April 2013. Originallyapproved in 2002. Last previous edition
15、approved in 2007 as F2205 07. DOI:10.1520/F2205-07R13.2For 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 page onthe ASTM website.Copyrig
16、ht ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1ecosystems 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 con
17、tamination are identified.Protection 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
18、to use dispersants. The applications 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. H
19、abitats other than those such 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
20、 families and species ofmangroves (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 mang
21、roves form thestructural basis 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 mars
22、hes in temperate climates.Mangroves 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
23、 the worldstropical shoreline; 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
24、 of hard corals andcoralline algae. They may be comprised of emergent orsubmergent reefal zones, or a combination of both.Geomorphically, barrier and fringing reefs protect the insularand continental coastlines which they border from erosion.Typically, the coral reef provides habitat for a large var
25、iety ofattached plants 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 spatialdo
26、minance of corals and coralline 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 Paci
27、fic seas. Tropical WestAtlantic 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
28、 discrete ecosystem that 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 rhizomesfaci
29、litates the sediment-binding 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 largenu
30、mbers of epiphytes which 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 veget
31、ationprovides ideal cover 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 thepneumatophores, or breathing
32、 pores typically located on spe-cial aerial roots or stems, through oil absorption from the watercolumn and through oil absorption through the roots fromcontaminated soil/sediment and ground water (6-12). Man-groves with oil on pneumatophores may die within about 5 to7 days, depending on oxygenation
33、 conditions at the site(13-15). Mangroves may die from high concentrations of oil inthe water 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 degrade
34、s only very slowly(23-27). 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 oc
35、curs slowly (34-36).Countermeasures 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, reducedgr
36、owth of adventitious roots, abnormal pneumatophores andmineral imbalance, and slow growth rates (42-45). Studiesshow that these effects will persist from 1 year up to 7depending on amount of oil and environmental conditions.6.2 Biota Associated with Mangrove ForestsMangroveforests provide shelter an
37、d support for an extensive system of3The boldface numbers in parentheses refer to a list of references at the end ofthis guide.F2205 07 (2013)2biota including algae, crustaceans, and molluscs. Dissolvedand dispersed oil can cause lethality to mangrove biota at levelsas low as 20 ppm and naphthalene
38、as low as 0.4 ppm onprolonged contact (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 c
39、an be exposed to oil by twomodes, 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). Coral
40、s are not usually subject toharmful 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
41、 high concentrations ofdissolved 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 dis
42、persed oil showed that behavioralreflexes 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
43、 provideshelter and support for 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).
44、Increasing amountsof oil availability, 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 re
45、sult inextensive mortality (17). 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).
46、Seagrasses are,however, particularly 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
47、the exposure of sea-grasses to 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
48、 oil availability, such as through the use ofdispersants, 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 ofth
49、e proximity of the dispersant 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
