Spills of Emulsified Fuels Risks and Response (2002) / Chapter Skim
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3 Ecological Effects: Summary and Evaluation of Available Information
3 Ecological Effects: Summary and Evaluation of Available Information
Pages 44-65
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From page 44... ...
The ecological effects associated with spills of floating oils (including crude oil and distilled products) can generally be categorized as: (1)
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From page 45... ...
Ecological effects associated with spills of emulsified fuels can be discussed in a similar fashion, and their effects will differ based on the physical, chemical, and biological behavior of the component compounds and the setting in which the spill occurs. UNDERSTANDING TOXICITY The physical effects associated with spills of petroleum products (e.g., smothering or coating of floating oil on birds, mammals, or other organisms)
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From page 46... ...
The LC50 values for the water-soluble fractions of reference oils and specific hydrocarbons, using a range of animals, provided the early evidence about which specific components of oils were responsible for the majority of the toxicity observed. Once data were obtained on mortality, sublethal and chronic toxicity testing was conducted to observe the magnitude of difference between the results of acute tests and chronic exposure parameters (growth, reproduction, physiology)
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From page 48... ...
The soluble PAH present in Orimulsion occur at very low concentrations, compared to other heavy fuel oils and crude oils (Anderson et al., 1974a; Table 2.2~. Even from spills of large amounts of crude oil, the water column seldom contains a high enough concentration for a sufficient period of time to produce acute toxicity.
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From page 49... ...
supports the view that AE contained in the water phase of Orimulsion would be diluted rapidly in open water. The available data suggest that the LC50 for either 48- or 96-hour exposure may be about 1 ppm, and a seven-day chronic test on the reproduction of Ceriodaphnia dubia reported a No-Observable-Effect Concentration (NOEC)
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From page 50... ...
. COMPARING TOXICITY VALUES AMONG DIFFERENT FUEL TYPES In an effort to place the risk associated with spills of Orimulsion into some context, much of the existing literature makes comparisons among Orimulsion and other petroleum products such as Fuel Oil No.
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From page 51... ...
First, unlike typical fuel oils where the distribution of various compounds of concern is essentially uniform, the distribution of compounds in multiphase fuels may vary dramatically among the components. For example, in any volume of Orimulsion-400, the bulk of the total PAH (3,000 ppm; Table 2.1)
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From page 52... ...
However, by keeping these relationships in mind and by assuming a maximum concentration of bioavailable PAH of 30 ppb, it is possible to examine and make some general comparisons among previous toxicity data (Table 3.4) for Orimulsion-400 and floating oils such as No.
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From page 53... ...
It is clear that the maximum concentration of PAH that can be produced in the water during either a toxicity test or a spill of Orimulsion is less than that produced by floating oils. It is important, however, to consider the additional contribution to toxicity from the AE in this product, as initial concentrations can be toxic to exposed organisms.
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From page 54... ...
After three days of preening and bathing in clean water, half of that amount remained, indicating that exposure of these birds is likely by ingestion. Although this study found the effects of Orimulsion exposure to be less injurious than those of a heavy fuel oil there was some loss of waterproofing in plumage at a low Orimulsion concentration and four hour exposure duration.
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From page 55... ...
UNDERSTANDING ECOLOGICAL RISKS ASSOCIATED WITH SURFACTANT Although the impacts of petroleum hydrocarbons on marine and aquatic organisms have been studied for years, the long-term chronic effects of the surfactants used in Orimulsion-400 and many other household products, are less well understood. Consequently, additional discussion of these compounds seems
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From page 56... ...
SPILL SCENARIOS In an effort to understand the ecological risks associated with spills of Orimulsion in a variety of environments, the potential physical, acute lethal and
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From page 57... ...
The discussion for these groupings begins with a general statement about factors contributing to overall effect, followed by a greater discussion of the potential effects on four major groups of organisms (i.e. wildlife, including birds and mammals; water column resources, including fish and invertebrates; benthic organisms, including epifauna and infauna; and nonplanktonic primary producers or vascular plants, including kelp in marine settings and plants and trees in freshwater settings)
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From page 58... ...
However, because of rapid dilution with depth benthic organisms would typically be at low risk. Second, suspended bitumen droplets and bitumen-sediment agglomerates could be mixed throughout the water column, where they could be ingested by benthic filter feeders.
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From page 59... ...
There is no information in the literature regarding the potential effects of Orimulsion floating residue on vascular plants, but it is likely that they are similar to those of other weathered heavy fuels (Michel et al., 1995~. The dispersed form of Orimulsion may interact with subtidal as well as intertidal primary producers.
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From page 60... ...
Orimulsion in a pond had bitumen droplets stuck on their feathers, resulting in a reduction in water proofing (Wolfe et al., 2001~. It is possible that the agitation of the water column by the swimming of the ducks in this confined water body promoted the coalescence and floating of the bitumen droplets.
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From page 61... ...
Effects on Benthic Organisms Spills of Orimulsion in freshwater environments have a greater potential than floating oil spills to impact benthic organisms because bitumen droplets are denser than fresh water. Very small bitumen droplets will remain in suspension under all but the most quiescent settings, so filter-feeding benthic organisms could be exposed to the cloud of droplets as they move past.
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From page 62... ...
physical effects associated with smothering or coating (2) acute lethal and sublethal toxicological effects of component compounds (such as polycyclic aromatic compounds)
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From page 63... ...
contribute to the toxicity of spilled fuel oils in the early stages of a spill, but these are present in such low concentrations in Orimulsion that they pose little risk to aquatic organisms. In addition, most of the PAH in Orimulsion occurs in the bitumen droplets, and the bioavailability of these compounds to non-filter-feeding organisms will likely be low, since the chemicals would first have to exchange into the water, at very dilute concentrations.
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From page 64... ...
Only an approximation of risks from spills of emulsified fuels in U.S. waterways can be made, using models that are based mostly on toxic concentrations derived from acute toxicity studies of nominal amounts of the untreated toxicant.
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From page 65... ...
. Complexly branched hydrophobic and hydrophilic moieties should be avoided in emulsified fuels because of their recalcitrance to degradation in sewage treatment facilities.
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