^
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/R-93/113D
July 1993
Chemical
Cleaning
Spills
Shoreline
Agents for Oil
Update State-of-the-Art on
Mechanisms of Action and
Factors Influencing
Performance
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EPA/600/R-93/113b
July 1993
CHEMICAL SHORELINE CLEANING AGENTS FOR OIL SPILLS
Update State-of-the-Art on Mechanisms of Action and Factors Influencing Performance
by
John R. Clay
on, Jr.
Science Applications International Corporation
San Diego, California 92121
EPA Contract No. 68-C8-0062
Work Assignment No. 3-48
SAIC Project No. 01-0895-03-1000
Project Officer
Choudhry S arwar
Risk Reduction Engineering Laboratory
Releases Control Branch
Edison, New Jersey! 08837-3679
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
Printed on Recycled Paper
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Disclaimer Notice
The information in this document has been funded wholly or in part by the United States Environmental
Protection Agency under EPA Contract No. 68-C8-0062 to Science Applications International Corporation. It
has been subjected to the Agency's peer and administrative review, and it has been approved for publication as an
EPA document. Mention of trade names or commercial products does not constitute endorsement or
recommendation for use.
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Foreword
Today's rapidly developing and changing technc logies and industrial products and practices frequently
carry with them the increased generation of materials that, if improperly dealt with, can threaten both public
health and the environment The U.S. Environmental Protection Agency is charged by Congress with protecting
the Nation's land, air, and water resources. Under a mandate of national environmental laws, the Agency strives
to formulate and implement actions leading to a compatible balance between human activities and the ability of
natural systems to support and nurture life. These laws direct the EPA to perform research to define our
environmental problems, measure the impacts, and search for solutions.
The Risk Reduction Engineering Laboratory is responsible for planning, implementing, and managing
research, development, and demonstration programs to provide an authoritative, defensible engineering basis in
support of the policies, programs, and regulations of the EPA with respect to drinking water, wastewater,
pesticides, toxic substances, solid and hazardous wastes,
and Superfund-related activities. This publication is one
of the products of that research and provides a vital communication link between the researcher and the user
community.
The purpose of this report is to provide an updai ed review of information from the available literature
for (1) the mechanism of action of cleaning by chemical 'agents for oil that strands on shorelines, (2) variables
affecting performance of these chemical agents, (3) evaluations of laboratory tests designed to assess performance
of such agents, and (4) a brief consideration of actual applications of chemical cleaning agents in field situations.
Considerations also are given to strengths and limitations of specific laboratory tests, including brief discussions
of the applicability of test results for estimating performance of chemical cleaning agents in field trials or
conditions encountered in real-world spill events. Finally, a modest attempt is made at providing
recommendations for needed research in the laboratory and field for chemical cleaning agents.
This review primarily summarizes work from both the peer-reviewed scientific literature and scientific
reports that have not been submitted for formal publication. Liberal use also is made of information presented in
several detailed reviews of chemical dispersants (e.g., NRC, 1989; Clayton and Payne, 1992). Although of
interest, information on toxicities of shoreline cleaning agents is beyond the scope of this review and will not be
considered.
E Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
iii
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Abstract
This report presents information on the following topics: (1) brief consideration of common cleaning
strategies for stranded oil on shorelines, (2) the mechanism of action of chemical shoreline cleaning agents, (3)
factors affecting performance and its measurement for chemical cleaning agents, (4) laboratory methods for
testing performance of such agents. (5) a brief summary of applications of chemical cleaning agents and their
performance in field trials and spills-of-opportunity, and (6) recommendations for future laboratory studies for
chemical cleaning agents. The discussion of laboratory methods for performance testing (Section 4) presents
information on the approach used for general laboratory tests, available information for identified tests, and
similarities and differences among tests. For each test, descriptions are presented for the laboratory apparatus
required, brief summaries of the testing procedures, differences among the methods, and considerations of how
the design of a particular method might affect results. With the understanding that the purpose of this report
centers on laboratory testing. Section 5 presents a brief discussion of field trials that have involved applications of
chemical shoreline cleaning agents. Information is presented for general approaches used in studies, limitations
encountered in such efforts, and the relevance of laboratory results to field situations.
This report was submitted in partial fulfillment of EPA Contract No. 68-C8-0062 by Science
Applications International Corporation under the sponsorship of the U.S. Environmental Protection Agency.
This report covers a period from September 1991 to Junel992. and work was completed as of 22 June 1992.
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CONTENTS
page
TABLES
FIGURES
SECTION 1: TREATMENT APPROACHES FOR REfc
SHORELINES
EDIATION OF STRANDED OIL ON
SECTION 2: GENERAL MECHANISM OF ACTION OF CHEMICAL SHORELINE CLEANING
AGENTS I ••
CHEMICAL FORMULATION OF SHORELINE CLEANING AGENTS
.. iii
....vi
1
4
7
SECTION 3: FACTORS AFFECTING MOBILIZATION OF OIL BY CHEMICAL CLEANING
AGENTS 1 11
OIL PROPERTIES AND CHEMISTRY J. 11
COMPOSITION OF SHORELINE CLEANING AGENTS 15
CHARACTERISTICS OF SHORELINE SUBSJTRATES 19
APPLICATION METHODS FOR SHORELINE CLEANING AGENTS 21
FLUSHING WITH WASH-WATER ].... 22
RATIO OF SHORELINE CLEANING AGENT TO ODL(SOR) 23
TEMPERATURE J.... ...24
SALINITY 24
SECTION 4: LABORATORY TESTING OF CLEANING PERFORMANCE FOR CHEMICAL
AGENTS | ; 28
28
29
30
Environment Canada Inclined Trough Procedure- 30
SAIC Swirling Coupon Procedure- • 30
CEDRE Glass Slide Procedure- 30
Tests with Natural Substrates 1 33
SAMPLING AND ANALYSIS METHOD.
LABORATORY TESTING METHODS....
Tests with Artificial Substrates
Exxon "Beach Washing Test
ADVANTAGES AND DISADVANTAGES O
Procedure- 33
F VARIOUS LABORATORY TESTS .'. 35
SECTION 5: FIELD TESTS OF CHEMICAL SHORELINE CLEANING AGENTS 38
SECTION 6: SUMMARY AND RECOMMENDATIO
SECTIQNTl REFERENCES
AEP.ENBIX.A: PREPARATION APPROACH FOR THIS REPORT 47
- LABORATORY STUDIES 40
41
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TABLES
page
1 Analysis of Prudhoe Bay crude oil and various boiling-point cuts for the oil
2 Physical characteristics and chemical properties of several crude oils
3 Oil types and physical/chemical properties [[[ .
4 Performance of products for surface washing and dispersion ....................................... .
5 Summary of features of laboratory methods to test performance of oil-cleaning agents
12
13
14
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FIGURES
page
6
7
8
9
10
The mechanism of oil removal by surfactants from a substrate surface 5
Vibrating screen and spiral classifier for washing oil-contaminated sand-gravel „. 8
Rheological properties in Pnidhoe Bay crude oil with natural weathering
over time in outdoor, flow-through seawater wave tanks 16
Results of laboratory tests of the effects of oil weathering on cleaning performance
by Corexit9580 and hot-water washing 1... 17
Surface washing versus dispersion performance for different products.
(a) Environment Canada, (b) Exxon . 20
Effect of water temperature on surface washing performance 25
Surface washing performance for different products with saltwater and freshwater flushing 27
Inclined trough test apparatus
Swirling coupon test apparatus
Exxon "Beach Washing Test" apparatus.
.31
.32
.34
vu
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TREATMENT APPROACHES FOR REMEDY
SECTION 1
TION OF STRANDED OIL ON SHORELINES
In the event of unintentional releases of oil into coastal waters, oil from slicks may ultimately become
stranded on shorelines. As noted by Canning et al. (1984), stranded oil can cause detrimental effects to
impacted biota due to (1) exposure to toxic components from the oil, (2) smothering of resident biota, and (3)
alterations of habitats (e.g., residual black surfaces on shoreline substrates show greater temperature variations
than lighter-colored surfaces, with attendant effects on resettlement preferences for recoionizing biota). For
short periods of time after release of oil onto water, a slick will maintain a chemical composition and physical
properties similar to the starting oil. However, the composition and properties will change rapidly due to natural
weathering processes that include volatilization and solubilization losses of selected components and/or water-
in-oil emulsification during continued exposure to water. The weathering processes are described in greater
detail in Section 3. Oil stranded on shorelines is almost always characterized by substantial degrees of
weathering. The accompanying changes in the chemical and physical state of the oil should be taken into
account in remediation strategies. At the same time, the specific situation and location of oil stranded on a
shoreline also can be major factors dictating the type and extent of remediation options.
Scientific criteria for determining whether treatment of stranded oil on a shoreline is necessary or
justified are continuing topics for study. However, if treatment of stranded oil is determined to be appropriate as
opposed to doing nothing, then a variety of remediation options can be considered. Some strategies that have
been used in the recent past have included (1) mechanical clean-up, (2) mechanical conditioning or reworking of
a shoreline, (3) bioremediation, and (4) treatment with chemicals that promote release of the oil from shoreline
substrates. Each of these options is discussed briefly in the following paragraphs, although the purpose of this
report is to consider the final option (chemical treatmen
Mechanical clean-up and removal is a common
been used for mitigation of oil spills (e.g., Turner et al.,
variety of approaches that include the following.
:) in detail.
and highly visible corrective-action option that has
1989; North et al., 1988). Activities can include a broad
o A wide spectrum of physical removal processes fe.g., manual clean-up by scraping, sorbent-treatment,
cutting, and removal of individual oiled materials; light mechanical treatment encompassing flushing,
steam cleaning, and sand blasting; and heavy mechanical treatment such as vacuum pumping and large-
scale removal of bulk shoreline substrate by heavy mechanized equipment).
o Application of high-pressure water jets (hot or cold) to release stranded oil from shoreline surfaces.
ass
Corralling of slicks in nearshore waters that are
and tow vessels).
isociated with stranded oil on shorelines (e.g., by booms
o Skimming of the preceding slicks from water surfaces by specially designed apparatus and vessels.
o Utilization of equipment constructed of synthetic polymers that enhance collection of oil and minimize
incorporation of additional water to form intractable water-in-oil emulsions.
All of the preceding options were used in efforts to remediate oiled shorelines following the EXXON VALDEZ
spill incident in Prince William Sound (Alaska). The procedures met with mixed success in Alaska depending
on specific situations in which they were used.
Major limitations inherent to mechanical clean
up approaches include the following*
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o Operations are generally time consuming for the Final extent of shoreline that is remediated.
o Operations are generally costly in terms of both equipment and personnel time.
o Operations may be particularly detrimental to a treated shoreline (e.g., mechanical destruction or
alteration of shoreline substrates, hot-water die-offs of impacted biota, and increased sediment erosion
and transport to nearshore waters with accompanying potential for reduced sunlight penetration,
enhanced siltation, and suffocation of nearshore organisms).
o Some shoreline substrates are more amenable than others to treatment by mechanical clean-up methods
(e.g., equipment access and shallower penetration of oil favor mechanical treatment on sand beaches as
opposed to shorelines of cobble or boulders).
o Major difficulties may be encountered in getting necessary equipment and personnel onto certain oiled
shorelines. ;
o Ultimate disposal of recovered oily wastes and associated clean-up materials may be costly and
problematic.
Studies of mechanical conditioning or reworking of oiled shorelines in Prince William Sound following
the EXXON VALDEZ spill also indicate that shorelines can be cleaned by natural processes related to winter
storm activity (Jahns et al., 1991; Owens etal., 1991). Much of the oil that remained on untreated shorelines in
Alaska in the spring of 1990 appeared to be associated with either the highest parts of the shoreline above the
limit of winter wave action or in coarse sediments below the limit of wave reworking. Additional studies in the
summer of 1990 evaluated mechanical conditioning or reworking of oiled shorelines (i.e., berm relocation to
zones of high winter-wave activity). By the spring of 1991, the latter shorelines exhibited substantial decreases
in amounts of stranded oil (Owens et al., 1991). Consequently, relocation of oiled sediment substrates to
shoreline zones that are subject to reworking by wave action can be a viable corrective-action option for
shoreline cleaning under appropriate conditions. However, limitations inherent to berm relocation are similar to
those identified above for general mechanical clean-up.
Bioremediation is a clean-up option that does not require substantial physical alteration of a shoreline
habitat Bioremediation is essenually an enhancement of natural biodegradation processes in which oil is
degraded by microorganisms (e.g., bacteria, fungi, unicellular algae, and protozoa). Enzymes synthesized by the
microorganisms catalyze the oxidation of oil constituents to intermediate metabolites, which can be either
incorporated into biomass or metabolized by single species or assemblages of microorganisms to carbon dioxide
and water. Biodegradation of oil can occur in situations where an oil-water interface, nutrients (e.g., nitrogen
and phosphorus), oxygen, and a suitable assemblage of microorganisms exists. The microorganisms will be
present in the aqueous phase and metabolize oil at the oil-water interface. Nutrients and/or oxygen frequently
are considered to be limiting for the biodegradation process because of the large excess of carbon present in the
oil. Additional factors that can influence rates of biodegradation of oil include temperature, the chemical
composition of the oil (which changes over time due to natural, abiotic weathering processes), and the total
surface area of the oil-water interface.
As noted above, bioremediation involves enhancement of the natural rate of biodegradation.
Bioremediation can involve addition(s) of either nutrient supplements (e.g., nitrogen and phosphorus) or oil-
consuming microbes to oil-contaminated systems. Addition of only a nutrient supplement is intended to
enhance biodegradation processes of indigenous populations of microorganisms. While not always conclusive,
information indicates that nutrient supplements have produced enhanced rates of oil degradation in certain
natural situations (e.g., oiled shorelines associated with the EXXON VALDEZ spill; Chianelli et al., 1991;
Pritchard and Costa, 1991; Tabak et al., 1991). Bioremediation products based on microbial inocula usually
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incorporate a mixture of nutrients and specific oil-consuming microbes. Although studies with products
containing specific microbial inocula may show enhanced rates of degradation of oil in laboratories, available
information does not appear to indicate that such products substantially enhance rates of degradation of oil in
natural systems beyond that due to nutrient enrichments! alone (Owen, 1991; Venosa et al., 1991).
Consequently, the greatest promise to.: bioremediation of stranded oil on shorelines appears to involve nutrient
supplements to assist degradation by indigenous microbial populations. However, successful utilization of
bioremediation agents for promoting degradation of oil
on shorelines will be subject to the following limitations.
o Appropriate natural assemblages of microorgani:
o Sufficient nutrients and oxygen must remain
iins must be present.
available to the microorganisms.
Bioremediation generally proceeds at a relativel
the most refractory components of oils.
The fourth option identified above for treating
/ slow rate, particularly to the complete disappearance of
stranded oil on shorelines involves use of chemical
cleaning agents. The purpose of such agents is to promote rapid release of stranded oil from shorelines for
reasons including biological sensitivity of indigenous fauna and flora to the oil, amenity considerations of the
shoreline, or concern about refloating of the oil and subsequent stranding on adjacent shorelines. While use of
.chemical cleaning agents may be appropriate under proper circumstances, certain limitations should be
recognized. The potential for toxic responses to the cleaning agents by indigenous fauna and flora must be
considered, although studies indicate that certain cleaning agents are relatively non-toxic (Fingas et al.. 1989).
Enhanced penetration of oil into permeable shorelines following treatment with chemical cleaning agents also is
not desirable. However, if conditions related to toxicity and substrate permeability are determined to be
acceptable, the use of chemical cleaning agents for treatment of stranded oil should be considered.
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SECTION 2
GENERAL MECHANISM OF ACTION OF CHEMICAL SHORELINE CLEANING AGENTS
Chemical agents for cleaning oiled shorelines can be included in three categories: (1) non-surfactant-
based solvents, (2) chemical dispersants, and (3) surfactant formulations especially designed to release stranded
oil from shoreline substrates (i.e.. shoreiine-cleaning-agents). The intended purpose in applications of agents in
all three groups is to facilitate mobilization or release of stranded oil from shoreline surfaces (e.g., rock faces,
cobble, gravel, sand, mud flats, beached logs, etc.). Depending on the specific circumstances, it is generally
desirable that chemical agents used for shoreline cleaning release oil from shoreline substrate(s) to (offshore)
surface waters where recovery of the oil is accomplished by mechanical procedures such as booming and
skimming operations. In biologically sensitive environments, the chemical cleaning agents should neither
facilitate dispersion of the treated oil into the offshore water column nor enhance penetration of the oil further
into permeable shoreline substrates. Cleaning-solvents and shoreline-cleaning-agents (i.e., groups 1 and 3,
respectively) are designed to minimize dispersion of treated oil as small droplets into associated water columns.
In contrast, chemical dispersants not only will promote dispersion of oil into water (i.e., their intended purpose)
but also can produce elevated concentrations of oil in permeable sediment substrates under appropriate
conditions (Clayton et al., 1989; Little et al., 1986; Dewling and Silva. 1979; Mackay etal.. 1979; Canevari,
1979). Hence, use of chemical dispersants for purposes of cleaning must be done selectively depending on the
particular circumstances inherent to an oiled shoreline. Their use may be appropriate on beaches with low
permeability and offshore waters in which the dispersed oil can be rapidly diluted to non-problematic
concentrations.
In cleaning agents that do not contain surfactants (i.e., group 1 above), the purpose of the solvent is to
soften or lower the viscosity of the treated oil. This can facilitate detachment of the oil from substrate surfaces
upon flushing with water (e.g., application of high-pressure water jets or agitation in a mechanical mixer).
Following release from a substrate surface, the oil should rise to the water's surface if its overall density remains
less than that of the water. The oil then can be recovered by mechanical means (e.g., booming and skimming
operations).
In contrast to non-surfactant-based solvent cleaners, chemical dispersants and shoreline-cleaning-ugents
(i.e., groups 2 and 3 above) are surfactant-based formulations containing solvents, additives, and surface-active
agents (i.e., surfactants). Solvents are primarily present to promote the dissolution of the surfactants in the
cleaning formulations and enhance penetration and mixing of the surfactants into oil. Additives may be present
for purposes such as increasing the biodegradability of the oil and improving the dissolution of the surfactants in
the oil. However, surfactants are the major ingredients in both chemical shoreline-cleaning-agents and
dispersants. Surfactants are compounds containing both oil-compatible (i.e., lipophilic or hydrophobic) and
water-compatible (i.e., hydrophilic) groups. Because of this amphiphatic nature (i.e., opposing solubility
tendencies), the surfactant molecules will have a tendency to reside at oil-water interfaces and reduce the value
of the oil-water interfacial tension. Reduced interfacial tension will favor dispersion of the oil as small droplets
into a water column in the presence of sufficient turbulence or mixing energy. Commercial formulations of
shoreline-cleaning-agents and chemical dispersants contain proprietary mixtures of two or more surfactant
compounds that have varying solubilities in water and oils.
The cleaning action of both shoreline-cleaning-agents and chemical dispersants is basically a detergent
action in which adhesion of oil to a substrate surface is reduced. A simplified representation of the process is
shown in Figure 1 (from Canevari, 1979). The size scale is exaggerated and the continuity of the process is
abbreviated in the figure for purposes of illustration. As indicated, oil initially adheres to (or wets) a substrate
surface as a film that is characterized by a relatively large contact angle 6 between the oil and substrate.
Following application of a shoreline-cleaning-agent or dispersant to the oil film, surfactant molecules orient at
the oil-water interface. The presence of the surfactants leads to a decrease in the oil-water interfacial tension
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.oil film
(a)
substrate
(b)
substrate
(c)
substrate
oil-wet substrate
chemical reduces
contact angle 3;
oil film "rolls up"
surfactant
prevents
redeposition
Figure 1. The mechanism of oil
surface, (from Canevari,
renioval by surfactants from a substrate
1979)
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' which in turn leads to a roll-up of the oil film into the indicated droplet shape (i.e., increasing oil-water
interfacial surface area). When the latter situation occurs, the contact angle 6 is reduced and the adhesion forces
between the oil and the substrate are accordingly reduced. As indicated in the figure, surfactant molecules also
may wet (i.e., orient themselves at) the substrate-water interface, with the hydrophilic and lipophilic ends of the
surfactant molecules oriented toward the water and substrate surface, respectively. The latter situation also may
assist in displacement of oil from the substrate surface if the surfactant molecules are better wetting agents than
the oil for the particular substrate surface. In either event, the surfactant-treated oil may be released from tltie
substrate surface into the adjacent water phase in the presence of minimal turbulence or mixing energy. If
surfactant molecules remain present at the oil-water interface (and thereby impart a fending-off action between
oil droplets), the oil will be unlikely to reform slicks on the water's surface (i.e., coalesce into larger droplets that
rise to the water's surface) or readhere to shoreline substrates. Prevention of coalescence or reaggregation of oil
droplets into surface slicks is an intended purpose of chemical dispersants. In contrast, shoreline-cleaning-agents
are designed to favor coalescence or reaggregation of oil droplets into surface slicks following release of the; oil
from substrate surfaces. As long as mechanical recovery of the oil from a surface slick is feasible (e.g., by
booming and skimming operations), maintaining oil as small dispersed droplets in a water column is generally
not a favored outcome for shoreline cleaning purposes.
A parameter that can be used to'characterize the differential solubilities of surfactant molecules in oil
and water phases is the hydrophile-lipophile balance (HLB). The HUB is a coding scale that ranges from 0 to 20
for nonionic surfactants and as high as 25 to 40 on an expanded scale for ionic surfactants. The HLB value takes
into account the chemical structure of the surfactant molecule. A specific value for the HLB will characterize the
tendency of the surfactant to dissolve preferentially in either an oil phase (low HLB) or an aqueous phase (high
HLB). The dominant group (i.e., lipophilic or hydrophilic) of a surfactant molecule will tend to be oriented in
the external phase of an oil-water mixture. For example, a surfactant mixture that is predominantly lipophilic
(e.g., with a low HLB of 1 to 8) will favor formation of water-in-oil emulsions (i.e., mousse). A mixture that is
predominantly hydrophilic (i.e., with a high HLB of greater than 12) will favor oil-in-water emulsions (i.e.,
dispersion of oil as droplets into a water column or release of oil as droplets from substrate surfaces to an
adjacent water phase). •
Formulations for chemical dispersants contain mixtures of surfactant compounds with an overall HLB in
the range of 9 to 11. This range will provide for relatively stable dispersions of oil droplets into a water column
(e.g., Brochu et al., 1986/87). For purposes of shoreline cleaning, Canevari (1979) describes the successful use of
a chemical dispersant for removal of stranded Bunker C oil from sea walls following the grounding of the
DELIAN APPOLLON in Tampa Bay (FL) in 1970. In contrast to dispersants, surfactant-based shoreline-
cleaning-agents are intended to promote the release of oil from substrate surfaces (as illustrated in Figure 1) but
not lead to long-term dispersion of the oil as small droplets into an associated water column. Rather, the oil
should rise to the surface of the water where it can be recovered by mechanical operations (e.g., booming and
skimming operations). As noted in Canevari (1979) and Fingas (1988), the surfactant mixtures in effective
shoreline-cleaning-agents will have an overall HLB value that is more hydrophilic (i.e., higher HLB value) than
that of a chemical formulation specifically designed to be a dispersant. As stated in Canevari (1979), this
"permits sufficient 'water compatibility' of the chemical so that it can be delivered in a water stream and/or be
compatible with the sea or fresh water environment. This preferred structure of the surface active agent (i.e.,
predominantly hydrophilic) also favors its effectiveness in preventing the redeposition of the removed oil." As
such, shoreline-cleaning-agents can promote the release of oil from substrate surfaces in the presence of water
(i.e., by the detergent mechanism shown in Figure 1), but the hydrophilic surfactants are then rapidly lost from
the oil-water interface due to dissolution into the surrounding water. Following this loss of the surfactants, the
oil-water interfacial tension will increase, which will favor coalescence of the oil and formation of slicks on the
water's surface. The latter is frequently the preferred result for a shoreline-cleaning-agent, which allows for
subsequent recovery of oil by booming and skimming operations.
The preceding descriptions of the mechanisms of action for the three types of chemical cleaning agents
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(non-surfactant-based solvents, chemical dispersants, anc shoreiine-cleaning-agents) is greatly simplified. In
fact, the actual processes involved in release of oil from shoreline surfaces will involve complex interactions
that depend on multiple processes and phenomena. Factors affecting release of oil from surfaces will include
successful application of a cleaning agent onto/into stranded oil, penetration/mixing of the agent into the oil,
alignment of surfactant molecules (if present) at the oil-water interfaces, dynamic reactions to which the
surfactant molecules will be subject at oil-water interfaces (e.g., selective partitioning and loss of surfactant
molecules to the surrounding water), and associated reac ions leading to reductions in adhesion of the oil to
substrate surfaces (which will likely be substrate-depend snt). Furthermore, oil (and the various cleaning agent
formulations to a more limited extent) are complex mixtures of compounds that vary from one product to the
next (e.g., crude oils from different sources as well as different cleaning agents). Of particular importance for
purposes of shoreline cleaning is the fact that oils immediately begin to experience rapid changes in their
chemical composition and rheological/physical properties due to natural weathering processes following release;
onto water or stranding on shorelines (Payne et al., 1983 1984,1991; Payne and McNabb, 1984; McAuliffe;
1989; Daling et al., 1990). Oil stranded on a shoreline will generally be in a substantially weathered state at the
time of application of a chemical cleaning agent. This Weathering can substantially affect the response of the oil
to the cleaning agent, which must be taken into account in the initial formulations of "effective" cleaning agent:;.
An additional complication for estimating performance of cleaning agents in field situations is the fact that
stranded oil on natural shorelines will almost always exhibit substantial degrees of spatial heterogeneity, which
will make collection of representative samples for estimating cleaning performance problematic. In summary,
the concept of shoreline cleaning and its associated performance measurement will involve interplays between a.
series of complex interactions in relatively controlled laboratory tests as well as uncontrolled real-world (i.e.,
field) situations. Discussions of the effects of a number of important variables (i.e., chemical, environmental,
and analytical) on release of oil from substrates are presented in Section 3 of this report.
CHEMICAL FORMULATION OF SHORELINE CL EANING AGENTS
As noted above, three types of chemical cleanir g-agents are currently available and used for treating
stranded oil on shorelines: (1) non-surfactant-based solvents, (2) surfactant-based chemical dispersants, and (3)
surfactant-based shoreline-cleaning-agents. Cleaning agpnts comprised of non-surfactant-based solvents
generally include petroleum distillate fractions with boiling points in the range of kerosene (200-250°C).
Solvent-cleaning operations with such agents can be performed by either transferring and treating contaminated
shoreline substrate in appropriate mechanical cleaning equipment or applying the solvent-agent in situ to an
exposed shoreline substrate. An example of shoreline cleaning equipment designed to treat contaminated
substrate with a kerosene-based cleaning agent is described in Webb and Turner (1991) and Turner et al. (1989).
The apparatus is based on commercially-available, portable gravel washing equipment as shown in Figure 2.
Briefly, contaminated substrate (e.g., sand and gravel) is agitated in a ready-mix concrete truck mixer with
kerosene, which reduces the viscosity of the oil and facilitates its detachment from the surfaces of the solids.
The kerosene-treated sand-gravel is then ^transferred onto a vibrating screen and cleaned by agitation under a
spray of seawater. Smaller solids pass through the screen and are transferred to a spiral classifier for additional,
agitation and cleaning. The seawater-rinseate (which contains released oil) is collected in oily-water gravity
settling tanks, where the oil is recovered by an apparatus such as a weir skimmer or an oil mop. Treated beach
materials (sand and gravel) obtained from settling or the spiral classifier are returned to a shoreline, while the
recovered oil is reprocessed or disposed of in an appropriate manner.
Non-surfactant-based cleaning solvents also may be applied directly to stranded oil on an exposed
shoreline. Such an application is then followed by agitajtion of the treated substrate by high-pressure water jets
to release the treated oil to adjacent waters (e.g., a trench or nearshore waters) where mechanical procedures are
used to recover the oil (e.g., booming and skimming operations; F. Merlin, undated). In situ application of a
softening solvent to an oiled shoreline requires that the solvent have a relatively low aromatic content for
considerations of toxicity to impacted biota. The solvent also should have a sufficiently low volatility (e.g., in
the boiling-point range of kerosene) to minimize evaporation losses of the solvent before softening of the oil can
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REDUCTION GEAR BOX
FINAL
CHAIN
DRIVE
i
TOP
SEARING
THRUST BLANKED
FLANGE ^ OFF
MOTOR
GUIDES
PIVOT BEARING ON
SPIRAL CENTRELINE
SIDE
DISCHARGE
x THRUST
ALIGNMENT WHEELS 4 ROLLE"S 2
DETAIL OF THRUST ROLLERS
AND BEARING ALIGNMENT WHEELS
FEI-D
WEIR
OVERFLOW
TO OIL/WATER
SEPARATION
TANKS
Figure 2. Vibrating screen and spiral classifier for washing oil-contaminated sand-gravel, (from Webb
and Turner, 1991)
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occur. Effective release of oil from substrate surfaces n ay require the use of pressurized water jets with high
temperatures if the solvent is unable to readily promote
release of the oil. With either cleaning in a mechanical
mixing apparatus or direct application of a cleaning solvent to a shoreline, the absence of surfactants strongly
favors formation of surface slicks in associated waters following release of oil from contaminated substrates.
Surfactant-based cleaning agents (i.e., shoreline-cleaning-agents and chemical dispersants) contain the
following types of chemicals: surface active agents (surfactants), solvents, and additives. The surfactants are die
most important component and promote reduction in the adhesion of oil to a substrate surface by detergency
reactions. As addressed in Fam (1983), initial formulations for chemical dispersants (i.e., in the 1950's) were
based on highly aromatic solvents and non-biodegradable emulsifters. While effective as dispersing agents,
these formulations proved to be very toxic to a variety of marine organisms. In an effort to reduce toxicity,
second-generation dispersant formulations began to appear in the late 1960's that were based on either
hydrocarbon solvents with lower aromatic contents or water and a biodegradable, low toxicity emulsifier of the
natural fatty acid polyglycol ester type. During the latter half of the 1970's, production was undertaken of third-
generation dispersant formulations that are produced in concentrated form. Application of these formulations
requires dilution with seawater, at which point relatively low toxicities for marine life are maintained. Non-
aromatic hydrocarbons (or water-miscible solvents such as ethylene glycol or glycol ethers) and less toxic
surfactants are currently being used in formulations for
shoreiine-cleaning-agents.
recendy developed dispersant formulations as well as
Exact compositions for commercial formulatio is of chemical dispersants and shoreline-cleaning-agents
remain proprietary. However, certain characteristics ofj these formulations are broadly known (e.g., Wells et al.,
1985; Brochu et al., 1987; Fingas et al., 1990) and indicate that a somewhat limited range of surfactants are
currently used. Specifically, surfactants in dispersants and shoreline-cleaning-agents can be grouped into four
classes:
o Non ionic. These are the most commonly used si irfactants in current formulations and are comprised of
compounds that have no discrete charge when dissolved in aqueous media. Examples include sorbitan
esters of oleic or lauric acids (e.g., sorbitan monooleate; HLB=4.3; distributed as Span 80), ethoxylated
sorbitan esters of oleic or lauric acid (e.g., ethoxylated sorbitan monooleate; HLB=15; distributed as
Tween 80), polyethylene glycol esters of unsaturated fatty acids like oleic acid, ethoxylated or
propoxylated fatty alcohols, and ethoxylated octylphenol.
o Anionic. Compounds in which the surface active portion carries a negative charge. Examples include
suifosuccinate esters (e.g., sodium dioctyl sulfosuccinate) as well as oxyalkylated C12 to C15 alcohols and
their suifonates (e.g., sodium ditridecanoyl sulfosuccinate).
o Cationic. Compounds in which the surface active portion carries a positive charge. An example is the
quaternary ammonium salt R(CH3)3N*C1", where R is an additional organic moiety or pan. Such
compounds are not commonly used in current dispersant or cleaning-agent formulations because of their
toxicity to a variety of organisms.
o Zwitterionic or amphoteric. Molecules contain! ig both positively and negatively charged groups that can
produce a net neutral charge. An example would be a molecule containing both a quaternary ammonium
group and a sulfonic acid group. Such compounds are not commonly used in current dispersant or
cleaning-agent formulations.
The specific combinations of surfactants, in chemical dispersants and shoreline-cleaning-agents will differ.
Surfactant combinations in dispersants are designed to promote release of oil from substrate surfaces by
detergency reactions, followed by overall dispersion of the oil as small droplets into receiving waters.
Surfactant mixtures in shoreline-cleaning-agents also p remote detergency reactions for release of treated oil
-------
from substrates. However, the more hydrophilic surfactants then may be lost to the surrounding water and the
oil coalesces into surface slicks that can be recovered by mechanical operations.
10
-------
SECTION 3
FACTORS AFFECTING MOBILIZATION OF OIL BY CHEMICAL CLEANING AGENTS
A variety of environmentally relevant factors can influence the ability of chemical cleaning agents to
mobilize oil from substrate surfaces in laboratory tests as well as field situations. A number of these factors are
discussed in this section.
OIL PROPERTIES AND CHEMISTRY
Both crude and refined petroleum products are
generalized characterization, crude and refined oils can
complex mixtures of hydrocarbon compounds. In a
be considered to contain compounds in five broad
categories: lower molecular weight (1) aliphatics and (2) aromatics, and higher molecular weight (3)
asphaltenes, (4) resins, and (5) waxes. Asphaltenes, resins, and waxes are defined in Bobra (1990). Asphaltenes
are compounds that are soluble in aromatic solvents but insoluble in alkane solvents. They generally are
considered to consist of condensed aromatic nuclei that contain alkyl and alicyclic systems with heteroatoms
(e.g., nitrogen, oxygen, sulfur, metals, and salts) in various structural locations. Asphaltenes will have carbon
numbers of 30 or greater and molecular weights of 500 to 10,000. Resins are complex higher molecular weight
compounds containing oxygen, nitrogen, and sulfur atoms. They are polar and have strong adsorption
tendencies. They normally will remain in solution following precipitation of asphaltenes (e.g., in alkane
solvents) and will adsorb onto surface-active material (e.g., Fuller's earth). Molecular weights for resins are
generally in the range of 800 to 1500. Waxes are hydrocarbon materials in asphaltene/resin-free oil that are
insoluble in not only methylene chloride at 32°C but also methyl ethyl ketone. Petroleum waxes also are
defined as higher molecular weight paraffinic substances (e.g., aliphatics) that crystallize out when an oil is
cooled below its pour point. Petroleum wax is generally divided into two groups: paraffin wax and
microcrystalline wax. Paraffin waxes are normal alkanes (n-alkanes) with carbon numbers of 20 to 40 and
melting points of 32 to 71°C. Microcrystalline waxes mainly consist of iso-alkanes with carbon numbers of 3:5
to 75 and melting points of 54 to 93°C.
Interactions between aliphatics, aromatics, asp laltenes, resins, and waxes in complex oil mixtures allow
for ail of the compounds to be maintained in a liquid state (Buist et al.,1989; Bobra, 1991),. That is, the lower
molecular weight components (i.e., the aliphatics and aromatics) act as solvents for the less soluble, higher
molecular weight components (i.e., the asphaltenes, resins, and waxes). The complex crude oil mixtures remain
as relatively stable liquid phases as long as the solvency interactions occurring in the bulk oil are maintained and
ihermodynamic conditions remain constant. If this equilibrium state is changed, the solvency strength of the oil
may become insufficient to keep the higher molecular weight components in solution and lead to their
precipitation as solid panicles. Accompanying changes in the physical state and chemical properties of the oil
can affect the way chemical cleaning agents interact with the oil.
Values for physical and chemical properties fo
various oils are summarized in Tables 1 and 2 (from
Clark and Brown, 1977) and Table 3 (data from Bobra and Callaghan, 1990). The three tables show that
differences exist between oils for a number of physical] chemical, and rheological properties such as viscosity,
pour point, specific gravity or density, oil-water interfacial surface tension, and chemical composition (e.g.,
general hydrocarbon classes as well as certain molecular elements). The ability of particular petroleum products
(i.e., either crude or refined oils) to be mobilized from substrates by shoreline cleaning agents will almost
certainly vary as a function of the physical and chemical properties of an oil. Specifically, increasing viscosity
will likely reduce tendencies for oils to be mobilized in two ways: (1) penetration and homogeneous mixing of
the chemical cleaning agents into the oil will be retarded and (2) the energy required to mobilize the stranded oil
from a particular substrate will likely increase. Furthermore, the specific chemical composition of an oil also
will likely be an important factor in the capacity of the oil to be mobilized by various shoreline cleaning agents.
11
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In addition to inherent differences in chemical compositions of different parent crudes and refined
products, an oil that is released into the environment (e.g., onto a water's surface and/or stranding on a shoreline)
will undergo a variety of rapid, dynamic changes in bot i chemical composition and physical properties due to
natural weathering processes (Jordan and Payne, 1980;
Payne and Phillips, 1985; McAuliffe, 1989; Daling et a
Payne and McNabb. 1984; Payne et al., 1983,1984;
1990). For example, many of the lower molecular
weight components (i.e., aJiphatics and aromatics) that are important for the solvency interactions for higher
molecular weight components (i..e., waxes, resins, and asphaltenes) are selectively lost from an oil due to oil-air
evaporation and oil-water dissolution during natural weathering processes. Furthermore, water is rapidly
incorporated into many oils to form stable water-in-oil emulsions (i.e., mousse), which are characterized by
lower oil-water interfacial surface tensions and substantially higher viscosities (e.g., >2000 cpoise; Payne et al.,
1983; Cormack et al., 1986/87rDaling et al., 1990). Examples of the latter trends are shown in Figure 3 (from
Payne etal., 1983,1991). :
Consideration of the weathered state of a stran led oil will be important in decisions to use chemical
cleaning agents in the field. Consequently, the timing c f application of cleaning agents to stranded oil relative "
to natural weathering processes should be critical to the performance (or effectiveness) of the cleaning agents.
Fiocco et al. (1991) evaluated the effect of weathering of oil on the cleaning performance of the shoreline '
cleaning agent Corexit 9S80. For the study, Alaska North Slope (ANS) crude oil was added to small aquarium
rocks and weathered for periods of time ranging from 0 to 14 days in a laboratory weatherometer. Artificially
weathered North Slope crude also was used in tests. At 0, 5,10, and 14 days of weathering, cleaning
performance of oil from the rocks (reported as percent of oil removed) was determined following treatments
with (1) Corexit 9580 followed by flushing with seawaier at 100°F or 38°C and (2) flushing with seawater only.
The results are illustrated in Figure 4. While treatment with the chemical agent resulted in enhanced cleaning
performance, it also should be noted mat this performance was achieved with only 40% as much water (1.0
versus 2.5 gal/sq. ft) and a temperature of 11CPF (versus 160°F).
Attempts have been made to formulate chemical agents (i.e., demulsifiers) that will counteract or
"break" water-in-oil emulsions because formation of mousse (i.e., water-in-oil emulsions) generally occurs soon
after release of oil onto water surfaces. Efforts toward (development of demulsifiers are addressed in Bridie et al.
(1980), Canevari (1982), and Buist and Ross (1986/87) although exact compositions of formulations are not
available for proprietary reasons. Such demulsifier agents might assist in shoreline clean-up operations if
penetration and mixing of chemical cleaning agents into a stranded oil is inhibited by the occurrence of water-
in-oil emulsification in the stranded oil.
COMPOSITION OF SHORELINE CLEANING AGENTS
As described in Section 2, shoreline cleaning i gents can encompass (1) non-surfactant-based solvent'!,
(2) surfactant-based chemical dispersants, and (3) surfactant-based shoreline-cleaning-agents. The desired result
following application of each type of agent can differ. Surfactant-based shoreline-cleaning-agents and non-
surfactant-based solvents are designed to promote relez se of oil from substrates, followed by formation of
surface slicks on receiving waters. Chemical dispersants are designed to promote release of oil, followed by
dispersion of the oil as droplets into the receiving waters to nonproblematic concentrations. The chemical
compositions of the cleaning-agent formulations are largely responsible for these different end-results.
Fingas et al. (1989) provide values for cleaning performance as well as dispersion for 21 products with
a common testing procedure. Cleaning performance was determined with Environment Canada's Inclined
Trough test (see Section 4. Dispersion performance was determined with Environment Canada's Swirling Flask
test (Fingas et al., 1987a and b; Clayton and Payne, 1992). Estimates for cleaning performance were determined
with freshwater and saltwater rinses of the trough system. Bunker C was the oil used for all tests (i.e., surface
washing and dispersion). Results are summarized in Table 4. The values for surface washing indicate that large
differences in performance do exist among cleaning agjsnts, which are reflective of the different compositions of
15
-------
s"
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WATER MCOfWORATION SY
OIL VS. Wf ATHERHVG TIME
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CRUDE OIL
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J « » «
TIMI
i » 10 II IS
WATER/OIL AND OIL/AIR INTERFACIAL
TENSIONS VS. WEATHERING TIME
1 H
• OIUAIN
A WATIN/OtL
a • « • w ia
U
Si
VISCOSITY VS. WEATHEPtlNQ TIME
SIMM *
' • WAV! TANKS
A MM IVA^OMAVIOM
1000
too
10
Figures. Rbeotogkal properties in Prudboe Bay crude oil with natural weathering over time in outdoor,
flow-through xawater wave tanks. Points ate means ± one standard deviation from ttaee wave
tanks, (from Payne et aL, 1991)
16
-------
OIL REMOVAL. %
CHEMICAL - C9560
FLUSH TEMP.: 110 F
VOL.: 1 gal/sq.ft.
5 10
DAYS IN WEATHEROMETER
PHYSICAL WASHING
FLUSH TEMP: 160 F
VOL.: 2.5 gal/aq.ft.
Figure 4. Results of laboratory tests of the effects of oil weathering on cleaning performance by Corexit
9580 and hot-water washing, (from Fiocco et ai., 1991)
17
-------
Table 4. Performance of Products for Surface Washing and Dispersion
surface washing dispersant
performance (%) performance
Product
o Biosotve
o Breaker-4
Crtrikleen 1850
Crtrikleen 1855
Crtrikleen FC1 160
Crtrikleen XPC
Con-Lei
o Corexrt7664
Corexrt 7664/lsopar
o Corexrt 9527
o Corexrt 9580
Corexit CRX-8
o Enersperse 700
Icoshine
o Jansotve
Lestoil
Mr. Clean
Nokomis 3
Palmolive
PYPRR
Sunlight
freshwater
2
17
24
14
10
37
8
25
17
13
45
14
1
12
25
9
13
13
14
12
16
saHwater
2
13
2
12
12
36
12
27
20
3
42
5
1
10
2
1
6
13
16
11
12
(%)
0
0
11
0
0
2
0
2
1
41
0
48
51
0
0
0
0
0
9
0
9
data from Fingas et al. (1989):
surface washing test = Environment Canada stainless steel trough
dispersion test = Environment Canada Swirling Rask
oil = Bunker C
o » product on U.S. National Contingency Plan Product Schedule (1991)
18
-------
the agents.
Information in Table 4 also indicates that gooc
dispersants. For example, Corexit 9580 is an agent des
surface-washing agents are not necessarily good
gned to be a good shoreline-cleaning-agent (Fiocco et
al., 1991). Surface washing and dispcrsant performance values for Corexit 9580 are 42% and 0%, respectively,
in saltwater. In contrast, the dispersants Corexit 9527, Corexit CRX-8, and Enersperse 700 gave performance
values of 3%, 5%, and 1% for surface washing and values of 41%, 48%, and 51% for dispersion. Trends with a
variety of other products in the table are less distinct (i.e., many agents exhibit relatively poor performance for
both surface washing and dispersion). Similar evaluations are reported by Fiocco et al. (1991) for surface
washing and dispersion performance for a variety of cleaning agents. Figure 5 presents plots of performance
values for surface washing versus dispersion from Fingas et al. (1989) and Fiocco et al. (1991). For reference,
data are shown for six products in Figure 5a that are either good dispersants (Corexit 9527, Corexit CRX-8, and
Enersperse) or good surface-washing agents (Corexit 9580, Corexit 7664, and Citrikleen XPC). Four of the six
(Corexit 7664, Corexit 9580, Corexit 9527, and Enerspsrse 700) are currently identified on the U.S. National
Contingency Plan Product Schedule (Table 4). The on
is Corexit 9580. However, both figures (i.e., 5a and b)
y product identified by Fiocco et al. (1991) in Figure 5b
indicate that certain products that are good surface
washing agents are poor dispersants (e.g., Corexit 9580).
CHARACTERISTICS OF SHORELINE SUBSTRATES
Natural shorelines include differences in physical locations and settings, types of substrates,
oceanographic conditions, and local and seasonal weather patterns. Canning et al. (1984) categorize shorelines
into four general groups: rocky shores, sandy beaches, tidal flats, and shallow subtidal benthos. Additional
variations in rocky shores can result from factors such as the degree of tidal exposure, the nature and hardness of
the rock, and the presence of boulders, u'de pools, and accumulations of sediment under rocks. Sediment
characteristics in intenidal areas will depend on the local geology of an area, which will be affected by local
water movements, slopes of shorelines, currents, and prevailing wind patterns. Shorelines at higher latitudes
also may include exposed ice surfaces. All of the preceding habitats will include variations due to salinity,
degree of exposure, tidal conditions, latitude and longitude, season, currents, type of substrate, etc. Variety also
will occur in the types and quantities of not only resident biota but also organic debris. Consequently, many
types of substrates can be available to interact with oil ihat strands on a shoreline.
Adhesion of oil to substrates will depend on tl e physical and chemical characteristics of not only an oil
but also different substrates. Important properties for substrates in adhesion reactions include the sizes of
particles (which relate to the amounts of surface area available for oiling), the surface characteristics of the
particles (e.g., surface roughness and porosity), and the chemical compositions of the substrates. Roughness and
porosity of individual particles (e.g., rock, wood, etc.) will influence the degree of penetration and persistence of
oil on or in panicles. Furthermore, the compositions of certain substrates (e.g., rock versus wood versus ice)
may be more compatible than others for adhesion and persistence of oil. Effects of surface characteristics and
compositions of substrates for adhesion of oil (as well as the subsequent performance of applied chemical
cleaning agents) is an area much in need of future research. In addition to properties of individual substrates,
the overall permeability of a shoreline also can be important for penetration and long-term persistence of oil.
For example, shorelines comprised of gravel and cobble substrates are considerably more permeable than
beaches comprised of sand or mud. Accordingly, oil vt ill penetrate deeper into a shoreline comprised of gravel
or cobble.
In addition to effects on penetration and persistence of oil, the nature of shoreline substrates also will
have major impacts on the feasibility and rationale for using specific types of chemical cleaning agents.
Feasibility requires that access to an oiled shoreline is possible with appropriate application equipment, which
can be a function of substrate type(s) and characteristics as well as the location of the specific shoreline.
Successful performance of chemical agents for cleanin; purposes also requires that the agents be effectively
19
-------
(a)
60
(b)
§40
^^
Cr
£
c
o
30-
S 2oH
i
TJ
10H
Enersperse 700
-*?- Corexit CRX-8
^ Corexit 9527
QD O
Corexit 7664 Citrikleen XPC Corexit9580
D n V V
n
10 20 30 40
surface washing performance (%)
50
100
8
o
2
60
4O
20
0
I
0
•
o
" o _
o o
»
o
"
n
i e
i i
o -
o
• «•
o
0
0
CemrttOStO 0
o to 1 o
oo nJ °
i • i
tO 20 30
surface washing performance (%)
Rgure 5. Surface washing versus dispersion performance for different
products, (a) Environment Canada's stainless steel trough and
Swirling Flask tests, respectively. Aqueous medium = saltwater;
oil - Bunker C. (data from Rngas et al., 1989). (b) Exxon beach
washing apparatus. Aqueous medium = saltwater; oil = weathered
Alaska North Slope crude, (from Fiocco et al., 1991)
20
-------
applied to the oil and that subsequent flushing of the treated substrate be sufficient to promote release of the oil.
Application of cleaning agents to oil that has penetrated deeply into a permeable substrate (e.g., cobble or,
gravel) can be problematic. At the same time, the nature of specific cleaning agents in relation to shoreline
matrices and locations can influence the rationale for using a particular type of cleaning agent. Non-surfactant-
based solvents and surfactant-based shoreline-cleaning-agents are designed to promote release of oil from
substrate surfaces, followed by coalescence of the oil as slicks on the water's surface that can be recovered by
booming and skimming operations. On the other hand, dispersants promote release of oil from substrate
surfaces followed by dispersion of the oil as small droplets into an associated water column. The latter situation
might be preferred if offshore water bodies and currents are sufficient to dilute the oil to non-problematic levels
or if booming and skimming operations for recovery of the oil are not feasible. However, use of dispersants for
shoreline cleaning purposes have been shown to be capable of producing higher concentrations of oil in
permeable substrates under appropriate conditions (Clayton et ai., 1989; Little et al., 1986; Dewling and Silva,
1979; Mackay et al., 1979; Canevari, 1979). Hence, ujse of chemical dispersants for purposes of shoreline
cleaning must be done selectively depending on the particular circumstances present at an oiled shoreline.
APPLICATION METHODS FOR SHORELINE CLEANING AGENTS
Major factors affecting releases of oil from substrate surfaces under the influence of chemical cleaning
agents in laboratory as well as field situations include
(1) the method of application of a cleaning agent to
stranded oil, (2) the method of penetration of the chemical agent into the oil (including the soak-time), and (3)
..I.
subsequent mobilization or release of the oil from the substrate surface. The mobilization or release requires
flushing with water from a pressurized jet or other sot rce of agitation (e.g., action of an incoming tide in the
field or mixing/swirling of water in test vessels in the
Successful application of a cleaning agent to
In general, the following criteria must be satisfied for
from a substrate.
laboratory).
stranded oil is critical for the ultimate release of the oil.
a cleaning agent to be effective in removing stranded oil
(1) The chemical agent must be successfully and
(2) The surfactant compounds (if present) and
uniformly applied to the stranded oil.
solvent must penetrate and diffuse into the oil.
(3) Surfactant molecules (if present) must attain ;oncentrations at oil-water interfaces that cause a
sufficiently large reduction in oil-water imerfacial tension to promote roll-up of the oil (see Figure 1) or
the solvents must cause sufficient softening of the treated oil.
(4) The oil must be released from the substrate under the influence of flushing with water that has
sufficient turbulence or elevated temperature
to break adhesive bonds at the oil-substrate interfaces.
Application of chemical agents to stranded o 1 in the field is generally performed by spraying and
occurs when the oil is not submerged in water. The application can be accomplished from three platforms: (1)
hand-held spray packs or motorized/wheeled spray carts that can gain access to the shoreline (F. Merlin,
undated), (2) nearshore boats, and (3) aircraft (helicopters or fixed-wing aircraft). Sufficient access to an oiled
shoreline when the latter is above water is required regardless of the application platform. Alternatively, oiled
shoreline substrate could be transferred to mechanica washing equipment for agitation with a cleaning agent
and then returned to the shoreline (Webb and Turner, 1991; Turner et al. 1989).
In spray applications, droplet size of the chemical agent can be important. Droplets should be of
sufficiently small size to achieve an even distribution] However, droplets that are too small when applied from
aircraft or boat platforms will be subject to wind drift! which can result in decreased application effectiveness.
Smedley (1981) discusses factors that can affect applications of chemical agents from aircraft including
21
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atmospheric transport of droplets (e.g., aircraft vortex effect on the terminal settling velocities for the droplets),
the actual velocities of the droplets, and atmospheric conditions such as wind and turbulence. Complicating
factors arising during aerial applications of chemical agents also are discussed in Lindblom and Cashion (1983),
Becker and Lindblom (1983), Dennis and Steelman (1980), and Lindblom and Barker (1978). Complications
pertaining to effective application of chemical agents onto stranded oil emphasize a major difficulty that can
affect final performance of chemical agents for removing stranded oil from surfaces. Specifically, agents may be
largely ineffective because of inadequate application to the oil, regardless of the capacity of the agent to promote
cleaning.
In addition to successful targeting of chemical agent onto stranded oil, additional factors related to the
application process will have bearing on cleaning performance. The duration of the soak-time in which the
cleaning agent diffuses into the oil prior to washing is important (Canevari, 1979; Crowley and Nightingale,
1983; Nightingale and Thomas, 1984; F. Merlin, undated; Fingas et al., 1989; Fiocco et al., 1991). Such times
are important to counteract the effect of natural weathering in oil. The higher viscosities of weathered oil will!
impede solvent-assisted penetration and diffusion of chemical agents into oil; hence, the desirability for
incorporating a soak-time into the application process. In most cases, soak-times of 10-30 minutes appear to te
sufficient for diffusion of cleaning agents into stranded oil (Crowley and Nightingale, 1983; Nightingale and
Thomas, 1984; F. Merlin, undated; Fingas et al., 1989; Fiocco et al., 1991). However, the exact duration of the
soak-time will depend on ambient temperature, which will affect rates of solvent evaporation and diffusion into
an oil. Soak-times that are not long enough may not allow for sufficient diffusion of a cleaning agent into an oil.
Soak-times that are too long may result in excessive evaporative loss of the carrier solvent from the cleaning
agent, with attendant decreases in overall cleaning performance (e.g., F. Merlin, undated, specifies that soak-
times should not exceed 2-3 hours). Consequently, application scenarios and procedures should be adapted to
individual spill situations.
FLUSHING WITH WASH-WATER ;
Following successful application of a shoreline cleaning agent to stranded oil, the desired result is to
facilitate release of the oil from the substrate surface to surrounding water. This release is generally assisted by
turbulent energy in an applied wash-water stream. The magnitude of the turbulence for removal of oil from
surfaces will depend on the nature of the oil (i.e., its original composition as well as the degree of weathering to
which it has been subjected), the degree of adhesion of the oil to a particular substrate, and the characteristics of
the specific cleaning agent and its penetration into the oil.
As discussed in Section 2, shoreline-cleaning-agents and dispersants promote release of oil from
shoreline surfaces. Surfactants responsible for the process cause roll-up of oil from surface films on substrate:;.
Application of relatively low-pressure, low-temperature water jets or possibly tidal action alone can then promote
release of the treated oil from surfaces. As discussed previously, treatment of stranded oil with an appropriate:
chemical cleaning agent can facilitate release of oil from substrate surfaces with not only smaller volumes of
wash-water but also lower temperatures (Fiocco et al., 1991). At the same time, increases in wash-water
temperatures can assist in the cleaning process for oil treated with chemical cleaning agents (see section below on
effects of temperature). Inclusion of chemical agents into wash-water sprays also may assist in cleaning. For
example, removal of Bunker C oil from a sea wall following the grounding of the DELIAN APPOLLON in
Tampa Bay in 1970 was accomplished by a preliminary application of a surfactant formulation (Corexit 8666) to
the stranded oil, followed by washing with water containing a second surfactant formulation (Corexit 7664)
(Canevari, 1979; Fiocco, 1991). It should be noted, however, that utilization of Corexit 7664 as both a
pretreatment and in the wash-water was not effective for removal of weathered oil from shoreline surfaces
following the EXXON VALDEZ spill (Fiocco et al., 1991; Fiocco, 1991).
High levels of turbulence in wash-water streams may not be desirable for oils treated with surfactant-
based agents because the oil might be mechanically dispersed into a water column or penetrate further into
22
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permeable shorelines. The latter situation is undesirable for considerations of not only toxicity to shoreline
infauna but also long-term persistence of oil in shoreline matrices. Studies indicate that treatment of oil with
chemical dispersants can result in higher concentrations of oil in permeable sediment matrices under appropriate
conditions (Clayton et al., 1989; Little et al., 1986: Mackay et al., 1979; Dewling and Silva, 1979; Canevari,
1979). Consequently, use of chemica.1 dispersant agents in particular to treat stranded oil on shorelines must be
done with caution. For example, the French policy through CEDRE (Centre de Documentation de Recherche et
d'Experimentations sur les Pollutions Accidentelles des Eaux) is to use dispersants as cleaning agents only when
oil cannot be recovered following its release from shoreline surfaces, the amounts of stranded oil are small or
widely scattered on a shoreline, or where tidal action or currents are sufficient to rapidly dilute the dispersed oil
(F. Merlin, undated). The policy in the United Kingdom is to use dispersants only for final polishing after
mechanical clean-up if use of dispersants is determined to be biologically acceptable (Webb and Turner, 1991;
Morris and Thomas, 1988; Morris et al., 1985; Nightingale and Thomas, 1984) or there is no risk of transfer of
oil to other shoreline areas (Matthew Sommerville, Warren Spring Laboratory, personal communication). It
should be noted, however, that a good shoreiine-cleaning-agem (as opposed to a dispersant) is designed to
minimize dispersion of treated oil, which should reduce certain limitations inherent to dispersants for purpose!!
of shoreline cleaning.
Non-surfactant-based solvents also are designed to facilitate release of treated oil from shoreline
surfaces in the presence of flushing with water. However, these solvents are only designed to soften the oil. As
a consequence, use of non-surtactant-based solvents normally will require that the wash-water be at higher
pressures and temperatures than needs to be the situation with surfactant-based agents. While the absence of
surfactants will minimize the likelihood for dispersion of oil into associated water columns or further penetration
of oil into permeable substrates, the higher pressures arid temperatures for the wash water may have detrimental
effects on biota in impacted shorelines.
It should be noted that shoreline cleaning by natural processes can lead to removal of stranded oil from
shorelines in the absence of applied chemical agents. Studies of oiled shorelines in Prince William Sound
following the EXXON VALDEZ spill indicate that beaches were cleaned by natural processes, particularly as a
result of winter storm activity (Jahns et al., 1991; Owens et al., 1991). Much of the oil that remained on beaches
in the spring of 1990 was associated with either the highest parts of beaches above the limit of winter storm
activity or in coarse sediments below the depth of wave reworking. Consequently, allowing natural wave action
to remove stranded oil from shorelines is a clean-up option that can be considered in lieu of chemical agents or
other treatment strategies.
RATIO OF SHORELINE CLEANING AGENT TO
OIL (SOR)
Successful removal of stranded oil from shoreline surfaces by chemical agents obviously will require
that a sufficient amount of cleaning agent be applied to the oil. In laboratory tests, Fingas et al. (1989) use a
ratio of shoreline cleaning agent to oil (SOR) of 1:5 (i.e., 30 uL of cleaning agent applied to 150 uL of BunkeirC
oil) for Environment Canada's inclined trough test (see Section 4). Fiocco et al. (1991) use an SOR of 1:2.5
(i.e., an application rate corresponding to 1 gallon of shoreline-cleaning-agent to 2.5 gallons of weathered
Alaska North Slope crude per 100 square feet of beach area) in studies with Exxon's "beach washing test"
apparatus (see Section 4). French policy through CED11E recommends use of an SOR of 1:3 (i.e., one volume
of cleaning agent to three volumes of oil; F. Merlin, un lated) for field operations.
Relatively detailed field studies evaluating the effects of a number of chemical dispersants for
removing a variety of oils from a natural, hard-packedjgently sloping sand and gravel beach in England are
described in Crowley and Nightingale (1983) and Nightingale and Thomas (1984). Specifically, oils placed on
test beaches included medium fuel oil, mousse (i.e., water-in-oil emulsion) of the medium fuel oil, mousse of
Arabian (Safaniya) crude, and mousse of North Sea (Claymore) crude. Applications (including soak-times of
10-15 minutes) to oiled beach substrates were made wi
h the hydrocarbon-based dispersant BP 1100X and 3 to 6
23
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unidentified commercial concentrated-dispersant formulations. SOR values for the hydrocarbon-based
dispersant BP 1100X were 1:3. whereas SOR values for the concentrated-dispersant formulations ranged from
1:7 to 1:27. Qualitative estimates of performance for release of stranded oil from test beaches (i.e., visual
estimation only) were compared for the different dispersants formulations. Conclusions stated that releases of
oil from the shoreline substrates were generally more effective with the concentrated-dispersant formulations
(which used SOR values of 1:7 to 1:27), although it must again be emphasized that the performance estimates
were based on visual observations rather than quantitative measurements of oil contents in beach samples.
TEMPERATURE
Temperature can play an important role in the performance of shoreline-cleaning-agents for removing
stranded oil from substrates. For example, temperature will affect viscosities and pour points of oils, which can
be important for not only the overall fluid characteristics of the oil but also the capacity for chemical treating
agents to penetrate and mix into the oil. If the viscosity of a stranded oil is sufficiently high (e.g., at low
temperatures), then a chemical treating agent might simply roll-off rather than penetrate and mix into the oil.
To a certain extent, the penetration or solvency characteristics of the carrier solvent in the cleaning agent arid the
duration of the soak-time after its application can counteract effects of increasing viscosity of oils. Increasing
temperature in the wash water used to facilitate removal of oil from a substrate surface also will enhance
removal of oil, although elevated temperatures can have deleterious effects on resident biota. '>
Evaluations of the effects of temperature in flush water are reported in Fingas et al. (1989) for
Environment Canada's inclined trough test (Section 4). Temperature in the water varied from 20°C to 100°C in
tests with three cleaning agents (Corexit 9580, Corexit 7664, and Citrikleen XPC) and a control without cleaning
agent. Cleaning performance increased from approximately 25-40% at 20°C to approximately 55-80% at 100°C
for the three chemical agents, whereas cleaning performance in the control increased from less than 5% to
approximately 10% (Figure 6). Data presented in Fiocco et al. (1991), as shown previously in Figure 4, also
suppon this trend for effects of temperature (i.e., treatment of weathered Alaska North Slope crude with Corexit
9580 facilitates greater release of oil from rock surfaces than treatment with water alone at higher temperatures).
It should be emphasized, however, that increasing temperature in flush water alone also enhances
removal of oil from substrates. The information in Figure 6 supports this observation, although absolute
amounts of removed oil are greater in the presence of the shoreline-cleaning-agents. Other studies indicate that
hot water washing alone can be effective for removing oil from sediment substrates. For example, Couillard and
Tran (1989/90) report removal rates of approximately 99% for Bunker C oil from beach sand (starting
quantities: 200 g of oil in 800 g of sand) in a hot water-digestor apparatus that employs vigorous agitation of the
oil-sand mixture in a heated pressurized vessel at water temperatures of 90-98°C. Clean-up operations in Prince
William Sound following the EXXON VALDEZ spill utilized hot-water spray-washing (approximately 140°F or
60°C) to assist in removal of stranded oil from shorelines (e.g., Nauman, 1990,1991). However, the potential
detrimental effects of hot-water washing to resident biota remains a serious concern (e.g., Holloway and Horgan,
1991). Therefore, hot-water washing in the absence of chemical cleaning agents remains controversial because
of effects that can accompany the necessary high temperatures.
SALINITY
Salinity of water can affect the performance of chemical dispersant agents for mobilizing (i.e.,
dispersing) oil from surface slicks on water (Clayton and Payne, 1992). Specifically, the intent of dispersant
formulations for use in marine waters is to provide maximum dispersion of oil at normal salinities of seawater.
Mackay et al. (1984) note that higher salinities lead to increased dispersion by dispersants that are only slightly
hydrophilic by deterring migration of surfactant molecules into the water phase, which is equivalent to a sailting-
out effect for the surfactant from the saline medium. Such a situation will tend to promote retention of
surfactant molecules at oil-water interfaces, which is important for lowering the oil-water interfaciai tension of
24
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100 r
Temperature (°C)
80
100
120
Figured. Effect erf water temperature on surface washing perfonnance with Environment Canada's
"Stainless Steel Trough* test (Gram Fingas et al., 1989)
i Fin
23
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the oil-dispersant mixture. Salinity also may affect the water solubilities of dispersant formulations by
influencing reactions related to the hydrophile-lipophile balance (HLB) of the dispersant mixture.
The effect of salinity (i.e., saltwater versus freshwater) on cleaning performance of various cleaning
agents was evaluated by Fingas et al. (1989) with Environment Canada's inclined trough test. Results from the
tests have been summarized in Table 4, and the saltwater-freshwater relationships are illustrated in Figure 7. As
indicated, many of the tested agents show similar cleaning performance in saltwater and freshwater. In
particular, this is true for certain agents that have been specifically designed as shoreline-cleaning-agents (e.g.,
Corexit 9580: Fiocco et al., 1991). This minimal influence of salinity on cleaning performance for formulations
designed as shoreline-cleaning-agents reflects the composition of surfactants included in the formulations. As
noted in Section 2, the surfactant mixtures in such agents is relatively hydrophilic in character. These
hydrophilic surfactants will be inclined to dissolve fairly rapidly from oil-water interfaces into a water phase,
regardless of the salinity of the water; hence, the minimal effect of salinity on cleaning performance in Figure 7
for agents such as Corexit 9580-. In contrast, the more hydrophobic character of surfactant molecules in
formulations designed as chemical dispersants will impart a greater dependence on salinity due to "salting out"
effects discussed above.
26
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50
40
30
20
10
Citrikleen XPC
D
ffl.
Corexit9580
•a
a
• Corexit 7664
0
10
20
30
40
50
saltwater performance (%)
Figure 7. Surface washing performance for different products with
saltwater and freshwate
r flushing. Environment Canada's
stainless steel trough test. Oil = Bunker C.
(data from Fingas et al.,
1989)
27
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SECTION 4
LABORATORY TESTING OF CLEANING PERFORMANCE FOR CHEMICAL AGENTS
The general purpose and objectives of laboratory testing can include, although not be limited to, the following.
o Screen types of chemical shoreline cleaning agents as a prelude to recommending their use in spill
situations or more expensive studies such as field testing, or determine limitations or restrictions for use
of specific formulations. It must be emphasized, however, that it is unlikely that any one test will give
results that are unequivocal as far as product performance is concerned because of the many variables
affecting results. Nevertheless, laboratory tests can be used at a minimum to provide information for
investigated products, such that products demonstrating poor performance for mobilizing oil from
substrate surfaces in the laboratory could be eliminated from further testing.
o Test performance for a variety of chemical shoreline cleaning agents to rank relative performance of the
products.
o Test the performance of chemical shoreline cleaning agents under carefully controlled laboratory
conditions to assess the role of oil type, weathering state, substrate type, oil-to-water ratio, cleaning-
agent-to-oil ratio, mixing energy, salinity, temperature, and application methods (e.g., application
mechanism, soak-time, etc.).
o Provide data that can be used in conjunction with other information by On-Scene Coordinators for
emergency response and contingency planning at real spills, stockpiling of approved shoreline cleaning
agents for particular environments and substrate types as well as oil types, and deciding whether or not
particular cleaning agents should be used.
o Generate data to validate and improve mathematical modeling efforts for predicting performance of
shoreline cleaning agents.
o Estimate concentrations for shoreline cleaning agents that might be appropriate for toxicity testing.
SAMPLING AND ANALYSIS METHOD
Estimation of cleaning performance by chemical agents can involve either measurement of oil on a
substrate before and after treatment or determination of oil released into the wash-water. In the limited number
of laboratory tests designed to evaluate cleaning agents, measurements of oil are generally performed by either
spectrophotometric or gravimetric analyses. For example, Exxon's "beach washing test" uses gravimetric
measurements before and after oiling and spectrophotometric analyses of methylene chloride (DCM) extracts of
the initial oiled gravel to determine quantities of oil on the test substrate before treatment with a chemical
cleaning agent. Oil released during the cleaning process is quantified by spectrophotometric analyses of DCM
extracts of the wash-water samples. Fiocco (1991) reports that reasonably "good agreement" is found between
oil measurements determined by the gravimetric and spectrophotometric methods. In contrast, Fingas et al.
(1989) estimate cleaning performance by gravimetric measurements alone in Environment Canada's inclimsd
trough test.
Spectrophotometric measurements for quantities of oil are generally performed on DCM extracts of
water or substrate-washing samples. Detection can be performed at a variety of wavelengths. Fingas et al.
(1987b) evaluate detection of oil in DCM at UV-visible wavelengths between 200 and 720 nm. Measurements
are made with three types of oil (Alberta Sweet Mixed Blend or ASMB, ASMB plus the chemical dispersant
Corexit 9527, and Issungnak crude). Analyses performed at wavelengths between 340 and 400 nm are reported
28
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to provide the best results in terms of consistency and repeatability for the oils tested. Analyses at wavelengths
less than 340 nm and greater than 470 nm suffer from limitations including lack of linear response with
concentration, poor reproducibility of values, or poor sensitivity for the oilin the spectrophotometer.
Consequently, choice of analysis wavelengths for spectrophotometric measurements of oil can affect the quality
of concentration estimates for oil. Fingas et ai. (1990) also note that the presence of water and some chemical
agents (e.g., dispersants) in DCM can affect absorbance readings in a spectrophotometer. Therefore, calibration
curves for quantitation of oil in samples should be developed by adding specified amounts of oil (and/or a
specific chemical cleaning agent, if used) to volumes of water equivalent to those in experimental samples,
extracting the standard oil-water solutions in a manner identical to a sample, and performing spectrophotometric
measurements on the extracts of the standards to generate an appropriate calibration curve for the specific oil
being used.
In Environment Canada's inclined trough test, cleaning performance is estimated by gravimetric
measurements of weight differences in an experimental substrate before and after treatment of the oil with a
candidate cleaning agent (Fingas et al., 1989). The weight differences reflect removal of the oil from the test
substrate due to the cleaning process. M. Fingas (personal communication) reports that gravimetric
measurements provide values with the highest degree of reproducibility as opposed to spectrophotometric
measurements of oil in extracts of water or substrate washings. These gravimetric measurements must be done
with particular care, however, because the weight measurements are made for small weight changes on a large
substrate-weight background. For example, the test is performed on a stainless steel trough and measurements.
are made for weight changes produced by removal of a portion of an initial 150-uL volume of oil (Bunker C)
from the trough, which is at least 16 cm long. Hence, small weight changes due to removal of oil are
superimposed on the much larger background weight o: the trough. If substrates other than stainless steel are to
be adapted to this testing procedure (e.g.. materials such as rock, porcelain, cement, or wood), gravimetric
measurements for oil removal could be affected by uptake and retention of cleaning agents or wash-water in the
substrates. Furthermore, substrates that might lose portions of their mass during the washing process (e.g.,
rocks, gravel, or sand) also could present serious limitations for estimating cleaning performance by gravimetric
measurements alone.
Separate from the analytical detection and measurement of oil in samples, an additional complication
that can affect estimates for cleaning performance can arise if permeable, three-dimensional substrate matrices
are utilized in the laboratory or field (e.g., sand, gravel or cobble substrates). Measurements of oil
concentrations in natural samples from oiled beaches indicate that substantial variability can exist in spatial
densities of oil in shorelines (Owens and Robson, 1987; Owens etal., 1987). This variability is caused by
factors such as differences in grain size (and, hence, suface area) of particles as well as heterogeneous pooling
of oil on and underneath the beach surface. Collection and analysis of samples of a sufficiently large size are
required to damp-out the spatial heterogeneity. In laboratory tests, use of environmentally-relevant, permeable,
three-dimensional substrates (e.g., the bed of pre-sized aquarium gravel for Exxon's "beach washing test") must
contend with difficulties in obtaining uniform coatings of (1) oil and (2) cleaning agents on substrate surfaces as
well as (3) getting uniform, definable washing of the treated surfaces with water. The latter considerations may
cause difficulties for obtaining reproducible estimates of cleaning performance in laboratory tests. Simple
substrate surfaces (e.g., stainless steel in the inclined trough test from Environment Canada) will minimize such
problems, although the environmental relevance of the
LABORATORY TESTING METHODS
latter substrate can be questioned.
At present, only a limited number of laboratory tests exist for evaluating the performance of chemical
cleaning agents under relatively well controlled conditions in a laboratory. Four methods are described below.
In contrast to the described methods, evaluations of chemical cleaning agents in the United Kingdom continue to
be performed with standard procedures used for chemical dispersants (Morris and Maninelli, 1983; Maurice
Webb, personal communication).
29
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Tests with Artifiyjal Substrates
Environment Canada Inclined Trough Procedure-
Fingas et al. (1989) report assessments of more than twenty experimental testing procedures to evaluate
performance of chemical shoreline cleaning agents. Of all procedures considered, the authors report that the
most repcatable results are obtained with a test utilizing a stainless steel trough. In the procedure, ISO uL of
Bunker C oil is applied to the inner surface of a small, preweighed stainless steel trough. The trough is them
suspended in a vertical position for 10 minutes. The 10-minute contact time between the oil and the trough
allows for (1) spreading of the oil on the substrate surface, (2) evaporative loss of volatile fractions from the oil,
and (3) formation of the adhesive bond between the oil and substrate. The trough is then reweighed to
determine the amount of oil adjded. A 30-uL volume of a chemical cleaning agent is then applied in an even
coating over the length of the oil on the trough (i.e., a volume:volume ratio of shoreline cleaning agent to oil of
1:5). A 10-minute soak-time is observed to allow the cleaning agent to diffuse into the oil. The trough is then
positioned vertically, and the surface of the treated oil is rinsed with two successive 5-mL volumes of water.
After manually removing residual droplets of water from the oil and trough with the moistened tip of a paper
towel, the trough is again weighed and the mass of oil removed by the cleaning process is calculated by weight
difference. Estimates of quantities of oil removed from the trough (i.e., performance) with this gravimetric
procedure are reported to be repeatable to ±5%. A schematic of a trough apparatus is shown in Figure 8.
» " ~
SAIC Swirling Coupon Procedure--
The test uses coupons of various substrate materials (e.g., stainless steel and porcelain), which are
suspended in standard glass beakers that are attached to an orbital-motion shaker table. Figure 9 illustrates the
setup. The basic apparatus for the test consists of (1) the variable-speed shaker table, (2) an apparatus frame
with coupon mounting arms capable of being raised and lowered (for attachment and immersion of the coupons),
(3) sets of stainless steel or porcelain coupons measuring 1-inch x 1-inch, (4) a set of 400- or 600-mL beakers to
serve as wash-water containers for the swirling process, (5) a set of retaining brackets to hold the beakers in
place on the shaker table, and (6) a programmable timer. In the test procedure, 48 uL of a reference test oil
(e.g., Bunker C or Prudhoe Bay crude) is evenly deposited as a slick across the surface of a clean, dry coupon.
The oiled coupon is allowed to stand at ambient temperature for approximately 18 hours to allow for evaporative
weathering of the oil as well as formation of an adhesive bond between the oil and substrate surface. At the end
of the oil-substrate contact period, the coupon is attached to a mounting arm of the support apparatus for the test
procedure. A 16-uL volume of cleaning agent is applied uniformly to the surface of the oil on the coupon. A
10-minute contact or soak-time is observed to allow for diffusion of the cleaning agent into the oil. A beaker
containing 250 mL of seawater is inserted into the retaining bracket on the shaker table beneath the mounted
coupon. Al the end of the cleaning agent-oil soak-time, the shaker table is turned on and the coupon (on its
mounting bracket) is lowered into the swirling beaker for 2 minutes. At the end of the 2-rninute period, the
shaker table is turned off and the coupon is withdrawn and allowed to drain over the beaker. The coupon and
the wash water are separately extracted with DCM, and the DCM extracts are analyzed spectrophotbmetrically
for their oil contents. The combined measurements in the coupon and water fractions allow for determination of
the mass balance of oil in the testing apparatus as well as estimation of the cleaning performance.
CEDRE Glass Slide Procedure--
A procedure for testing of chemical cleaning agents in France is currently being evaluated by the
Centre de Documentation de Recherche et d'Experimentations sur les Pollutions Accidentelles des Eaux
(CEDRE, Plouzane, France). Details of the procedure have been generously provided by Francois Merlin
(CEDRE, personal communication). Briefly, Bunker C oil is heated to 50°C. A 0.5-g amount of the heattid oil
is then uniformly deposited onto a clean, dry glass (or quartz) slide. The slide is weighed before and after
30
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Figure 8. Inclined trough test apparatus
31
-------
•^r stationary
support rack
for coupons
orbital motion for beakers
on shaker table
Figure 9. Swirling coupon test apparatus.
32
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application of the oil to determine the amount of oil deposited on the slide. The slide is allowed to stand for 20
minutes in a horizontal position to allow for formation of an adhesive bond between the oil and substrate
surface. Approximately 0.2S-0.30 g of a chemical cleaning agent is then applied from a spray gun (e.g., lens-
cleaner atomizer bottle) onto the oil. The chemically-treated oil is allowed to stand on the slide for 10 minute::
(i.e., a soak-rime) to allow the chemical agent to diffuse into the oil. Seawater is then sprayed at a rate of 100 ±
5 L/Iiour (28 ±1.5 mL/sec) onto the oiled surface of the slide for 20 seconds. The spray nozzle for the seawatcr
is positioned perpendicular to the slide and at a distance of 6-7 cm. The slide is then placed in a 250-mL beaker
and extracted with DCM. All of the OCM-extract and any accompanying water are transferred from the beaker
into a separatory funnel. The beaker is rinsed two additional times with DCM and the latter rinses also are
added to the separatory funnel. After shaking of the separatory funnel and separation of the DCM and water
phases, the DCM is passed through anhydrous sodium sulfate to remove residual water. The final DCM extract
is analyzed spectrophotometrically for oil content.
Tests with Natural Substrates
Exxon "Beach Washing Test" Procedure--
Fiocco et al. (1991) report on the development
and testing of the product Corexit 9S80 as a shoreline-
cleaning-agent. Included in this reference is a brief description of a laboratory testing procedure to evaluate
cleaning performance involving use of beaker-sized "beaches" composed of small aquarium rocks. The
procedure was developed and used by Exxon to test cleaning agents in the laboratory in response to the EXXON
VALDEZ oil spill. Details of the procedure have been 'generously provided by R.J. Fiocco (Fiocco, 1991). In
the procedure, a weathered preparation of Alaska North Slope crude oil (i.e., the greater than 521°F or 272°C
distillate fraction) is allowed to soak onto commercial aquarium gravel that has been sieved to a size range of
0.132-0.157 inches (i.e., 3.35-3.99 mm). The oil-application rate to the gravel is 2.5 g oil/48 g dry roek, which
is reported to correspond to an application rate of 2.5 gallons of oil per 100 square-feet of gravel in a field
situation (e.g., certain shorelines impacted by the EXXON VALDEZ spill). Oil content on the gravel is
determined by (1) gravimetric weight gain of the rock (before and after oiling) and (2) extraction of a
representative sample of the oiled rock with methyiene chloride (DCM), followed by gravimetric determination
of the oil residue in the DCM extract. For testing of cleaning agents, a bed of the pre-oiled gravel is placed on
top of a convex glass support in a stainless-steel wire-mesh basket, which is placed in a specially-fabricated
apparatus funnel. The oiled-gravel is then sprayed with a chemical cleaning agent at a loading of 1.0 g cleaning
agent/48 g dry rock (ratio of cleaning agent to oil of 1:2.5). A soak-time of 1 hour at 5°C is observed to allow
the chemical agent to diffuse into the oil. The treated gravel is then washed with 100 mL of seawater at a rate of
50 mL/minute for 2 minutes. The wash water percolates through the gravel bed draining in a roughly horizontal
direction because of the convex glass support beneath the gravel in the wire-mesh basket and exits through the
tip of the apparatus funnel into a 125-mL separatory funnel. A schematic illustration of the apparatus and
separatory funnels is shown in Figure 10. Separate water samples of 25-mL volumes are collected from die
separatory funnel at 1- and 5-minute times after all wash water has been collected in the separatory funnel.
Differences in measured oil contents in the 1- and 5-minute samples are intended to reflect the rate of settling of
dispersed oil in the water in the separatory funnel and are designed to estimate the stability of the oil dispersion
in the water (i.e., oil still present in the 5-minute sample, relative to that in the 1-minute sample, represents oil
characterized as a relatively stable dispersion). The 1- and 5-minute water samples (25 mL each) and all
remaining water in the separatory funnel (50 mL) are extracted with DCM and analyzed for their oil contents
with a spectrophotometer (at 580 nmeters absorption) relative to an oil standard curve. The results are used to
estimate the cleaning performance of the chemical agent by comparing the summed amount of oil from the thiree
samples (i.e., 1-minute 25-mL volume, 5-minute 25-mL volume, and remaining 50-mL volume) with the
gravimetric measurement of the total amount of oil on the gravel before treatment with the cleaning agent
Although no quantitative estimates of precision for measurements are provided, "good agreement" is reported
between the gravimetric and spectrophotometric results for oil amounts (Fiocco, 1991). Final results with the
procedure are intended to provide estimates for (1) cleaning performance (i.e., summed oil from all water
33
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apparatus funnel
gravel bed
250-mL separately funnel
Figure 10. Exxon "Beach Washing Test" apparatus, (from Fiocco, RJ., undated)
34
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samples relative to the gravimetric estimate of the initiz 1 oil content on the gravel) and (2) oil-dispersion
performance (i.e., comparison of oil amounts in the 1- and 5-minute water samples). Examples of the
relationships between the values for (1) cleaning performance and (2) dispersion performance have been shown
in Figure 5b. Estimates for dispersion as well as cleaning performance are useful because it is generally
undesirable for cleaning agents to promote dispersion of oil.
ADVANTAGES AND DISADVANTAGES OF VAR
OUS LABORATORY TESTS
Table 5 summarizes features and essential coir ponents in the preceding testing methods. To assist in
discussions of advantages and disadvantages of the various procedures, the table includes information for
substrate types, oil-to-substrate contact times, method of washing of treated oil, wash-water volume, oil-to-waiter
ratio (OWR), cleaning agent-application method, cleaning agent-to-oil ratio (SOR), soak-time for mixing of
cleaning agent into the oil, and relative rating for overall complexity of the testing procedure and its operation.
Complexity is a qualitative variable that will include factors such as the number of tests that can be performed in
a given period of time with an apparatus, the training and skill level of an operator required to perform a
particular test, and the overall cost to acquire a particular apparatus."Information in the table is relevant to
discussions of advantages and limitations of the various testing procedures.
Measurements of oil for estimating cleaning performance in the Exxon "beach washing test" (Fiocco et
al., 1991; Fiocco, 1991) utilize spectrophotometric analysis of oil in wash-water samples and
gravimethc/spectrophotomethc measurement of oil loading on the initial aquarium gravel substrate. Fiocco
(1991) notes that reasonably "good agreement" is found between oil measurements determined by the
gravimetric and spectrophotometric methods. In contrast, all measurements of oil for estimating cleaning
performance in Environment Canada's inclined trough test are determined by gravimetric methods (Fingas et id.,
1989). M. Fingas (personal communication) reports that values for cleaning performance are more reproducible
with gravimetric measurements as opposed to spectrophotometric measurements of sample extracts. It seems
reasonable that the latter observation should be confirmed, however, particularly if gravimetric measurements
are made for small weight differences (e.g., the weight-fraction of oil removed from a starting amount of 150 uL
of Bunker C oil in the stainless steel trough apparatus).
affected by uptake and retention of a cleaning agent or
than stainless steel such as rock, porcelain, wood, etc.).
the washing process (e.g., gravel or rocks such as in the
At the same time, gravimetric measurements could be
vash-water into porous substrates (i.e., materials other
Substrates that could lose portions of their mass during
Exxon "beach washing test") also would appear to have
serious limitations if cleaning performance is based exclusively on gravimetric measurements. All
measurements of oil in SAIC's swirling coupon test and CEDRE's glass slide test are made by
spectrophotometric measurements of DCM extracts of samples.
As for the choice of substrates used in tests to evaluate cleaning performance, it is desirable that
substrate test-materials mimic real-world substrates as much as possible to provide environmental relevance to
results. However, it must be emphasized that substrates on natural shorelines encompass a broad variety of
types and characteristics, which also can include substantial degrees of heterogeneity on small size scales (see
Section 3). Consequently, it is unlikely that any single testing substrate or procedure will provide broad
relevance to all environmental surfaces and situations. In light of this, the following inherent advantages and
disadvantages of the different testing procedures can be summarized for their capacity to indicate cleaning
performance in the laboratory as well as their capacity to represent real-world situations.
Artificial substrates are used in Environment Canada's inclined trough test (stainless steel), SAIC's
swirling coupon test (stainless steel and porcelain), andlCEDRE's glass slide test (glass or quartz). The
relevance of results from these tests might be subject to discussion because of uncertainties involving
comparabilities of wetting and adhesion properties of oil as well as its cleaning from the various substrates as
opposed to substrates that are more likely to be encountered on natural shorelines (e.g., rock faces, cobble,
gravel, sand, silt, clay, wood, ice, etc.). However, the variety of substrate types that can be encountered on real-
35
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world shorelines makes selection of an appropriately rep esentative substrate for laboratory testing problematic.
In particular, it seems desirable to have a substrate for la )oratory testing that can have the following
characteristics: (1) the substrate can be well defined in terms of its morphological and chemical properties
(chemical composition, surface roughness, porosity, etc.), (2) the surface properties are relatively uniform over
the entire surface (i.e., an absence of heterogeneity), and (3) the substrate should be readily available from
commercial sources. These criteria can be satisfied for materials such as stainless steel, porcelain, glass, and
quartz. In contrast, Exxon's "beach washing test" utilizes commercially-purchased aquarium gravel with a pre-
defined panicle-size range. Use of gravel should provide greater environmental relevance than stainless steel,
porcelain, or glass surfaces. The sizing of the gravel also should limit variability in the overall surface area
available for oiling. Consequently, the gravel substrate in the Exxon procedure is attractive from the perspective
of its greater environmental relevance. However, efficient and definable application of a cleaning agent to all
oiled surfaces as well as uniform washing of all surfaces in the gravel bed will be problematic. Furthermore,
differences in commercially-available aquarium gravel from different manufacturers and sources will occur.
As for overall simplicity for the different testing procedures, acquisition of the necessary materials and
conduct of actual tests are relatively straightforward and simple for Environment Canada's inclined trough,
S AIC's swirling coupon, and CEDRE's glass slide methods. In contrast, Exxon's "beach washing test" either
requires special fabrication for certain pieces of equipment (e.g., the apparatus funnel and stainless-steel mesh
basket) or adoption of comparable, commercially-available alternatives. The Exxon test also requires a more
involved determination of oil present in each batch of initial gravel substrate (i.e., gravimetric and
specirophotometric measurements) as well as more sample extractions and measurements per test (e.g., 3 water
samples per test for estimating total oil, oil released by washing, and oil dispersed into the wash water).
37
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SECTION 5
FIELD TESTS OF CHEMICAL SHORELINE CLEANING AGENTS
Use of chemical agents for promoting clean-up of stranded oil on natural shorelines has been limited
and generally used on only small scales. In part, this is due to the negative image associated with the historical
use of dispersants for purposes of cleaning oiled shorelines. In particular, the grounding of the tanker TORREY
CANYON off the western tip of Cornwall (England) in 1967 resulted in the release of 119,000 tons of Kuwait
crude oil. An estimated 14,000 tons of the oil stranded along 150 km (93 miles) of shoreline on West Cornwall
(Southward and Southward, 1978: Nelson-Smith, 1978),. By itself, the oil was relatively non-toxic. However,
stranded oil on shorelines was treated with 10,000 tons of first-generation chemical dispersants, which resulted
in substantial kills of resident biota in areas receiving heavy treatment with dispersants. Recoveries of biota in
areas receiving large-scale dispersant application have required periods of ten or more years. Consequently, any
clean-up benefit from the dispersant usage was outweighed by the detrimental effects on impacted biota. It
should be noted, however, that the dispersants used in the TORREY CANYON incident were first-generation
formulations, which contained highly toxic aromatic solvents and surfactants that did not readily biodegrade. As
noted in Section 2, the compositions and toxicities of dispersant formulations have changed considerably since
the time of the TORREY CANYON: Furthermore, many of the application dosages and procedures used for the
TORREY CANYON spill were inappropriate for the specific conditions encountered. However, the negative
impression from the TORREY CANYON incident remains as an obstacle to gaining public acceptance for use of
chemical agents as an option for clean-up of oiled shorelines, even under appropriate circumstances.
There are instances in which appropriate use of chemical cleaning agents (including chemical
dispersants) appear to have assisted in the removal of stranded oil from shorelines with minimal environmental
impact For example, Canevari (1979) describes successful treatment with a chemical dispersant of stranded
Bunker C oil on sea walls following the grounding of the DELIAN APPOLLON in Tampa Bay (FL) in 1979
Little and Scales (1987) summarize results from field tests in which stranded, slightly weathered Nigerian, crude
oil and an emulsified medium fuel oil (mousse) on salt marsh and sand flat shorelines were created with the
third-generation chemical dispersant Enersperse 1037. Control plots receiving comparable applications with
each of the latter oil types but without dispersant treatment were included on each shoreline surface.
Measurements of total hydrocarbon (THC) concentrations in sediment samples indicated that chemical
treatments of both the crude oil and the weathered mousse on the low-energy sand flat were accompanied by
reductions in THC concentrations, although precision estimates for concentrations were not provided. THC
results from dispersant-treated and untreated plots on the salt marsh were less conclusive. Natural movements of
sediments on both shorelines over time complicated interpretation of results. In Prince William Sound (AK)
following the EXXON VALDEZ spill, treatment of stranded oil with the shoreline-cleaning-agent Corexit 9580
appeared promising, although approval from appropriate regulatory agencies to use this agent on a wide-scale
basis was not received (Fiocco et al., 1991).
In general, documentation of the use of chemical cleaning agents to successfully promote clean-up of
stranded oil on natural shorelines is limited. This is due in pan to sampling and analytical difficulties associated
with collection of appropriate samples to confirm cleaning performance for chemical agents. As noted in
Section 3, measurements of oil concentrations in natural samples from beaches impacted by spills indicate that
substantial degrees of spatial variability in distributions of oil generally exist (Owens and Robson, 1987; Owens
et al., 1987). This variability is caused by factors such as differences in grain sizes (and, therefore, surface
areas) of particles as well as heterogeneous pooling of oil on and underneath beach surfaces. Damping-out of
the effects of such spatial heterogeneity requires collection and analysis of samples of sufficiently large size,
which may be problematic from the standpoint of both collection and analysis. Furthermore, estimates of
cleaning performance for treatment of stranded oil with chemical agents in field situations frequently appear to
be based on qualitative, visual evaluations of performance rather than quantitative measurements of oil
concentrations in treated and untreated-control beach plots (Canevari, 1979; Crowley and Nightingale, 1983;
38
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Nightingale and Thomas, 1984; Fiocco et al., 1991). Decisions for remediation actions also can be based on
whether chemical treatments might be viewed as no more effective than other treatment actions such as hot-
water washing (Fiocco el al., 1991), although hot-water washing can have severe effects on resident biota
(Holloway and Morgan, 1991). In those instances where chemical concentrations of oil in sediment substrates
have been determined (Little and Scales, 1987), natural movements of sediment substrate over time and spatial
heterogeneity (i.e., patchiness) of oil complicate interpretation of results for estimating cleaning performance.
In light of the absence of conclusive quantitative data, studies still need to be performed to evaluate the
usefulness of chemical cleaning agents for treatment of oil stranded on natural shorelines. Toward this end, the
American Petroleum Institute and the Marine Spill Response Corporation are jointly formulating designs for
controlled field experiments that would test various lowTimpact clean-up methods for removal of stranded oil
from natural habitats (American Petroleum Institute, 1992). The preliminary study design for one experiment
calls for use of a weathered crude oil that would be applied to a salt marsh habitat. Four treatment methods are
planned for evaluation with separate test plots: (1) low-pressure flushing with seawater at ambient temperature,
(2) moderate-pressure flushing with seawater at ambient temperature, (3) treatment of stranded oil with a
commercially-available chemical cleaning agent, and (4) physical removal or cropping of oiled plant vegetation.
An additional test plot would be exposed to a dispersed form of the weathered crude oil. Treated and control
plots, each with oiled and unoiled sections, would be compared over time to evaluate the effects and the rate and
extent of recovery to natural conditions. Among other i £tns,;the study would allow for evaluation of the
effectiveness of a chemical cleaning agent for treatment] of stranded oil in a salt marsh habitat relative to low-
and moderate-pressure washing methods. The study is tentatively expected to start in late spring or early
summer 1993.
The use of chemical agents to assist in the cleaning of stranded oil on natural shorelines should only be
done under appropriate circumstances and with appropriate chemical agents. As noted in Section 2, chemical
agents for cleaning can be in three groups: (1) non-surfajctant-based, low-aromatic-content hydrocarbon solvemis,
(2) surfactant-based, second- and third-generation chemical dispersants, and (3) surfactant-based shoreline-
cleaning-agents. Non-surfactant-based solvents promote cleaning by softening oil, which can then be more
easily removed from substrate surfaces by moderate-temperature water jets or agitation and subsequent recoveiry
as slicks from water surfaces. Considerations that must be addressed for use of non-surfactant-based solvents
include the necessary temperature for wash-water, the degree of agitation that would be imparted to a shoreline
to promote cleaning, and the accessibility to offshore waters for booming and skimming operations. Surfactant-
based dispersants and shoreline-cleaning-agents promote release of oil from substrate surfaces by detergency
reactions. Dispersants promote dispersion of treated oilj into an associated water columns, although enhanced
penetration of oil into permeable shoreline substrates also can result. Chemical shoreiine-cleaning-agents are
intended to promote release of oil from surfaces, followed by coalescence of the oil into surface slicks that can
be recovered by mechanical operations (e.g., booming and skimming). In summary, utilization of one or more
of the chemical cleaning agents will depend on the specific circumstances at a particular location.
Consideration must be given to accessibility to offshore} waters for booming and skimming operations, the
permeability of the shoreline matrix, the capacity of offshore waters to dilute released oil, and the sensitivity of
resident biological populations. For example, studies have shown that chemical dispersants increase
concentrations of dispersed oil in water columns and can produce higher concentrations of oil in permeable
substrates (Clayton etal.. 1989; Little et al., 1986; Macicay et al., 1979; Dewling and Silva, 1979; Canevari,
1979). In the latter situations or in the presence of sens itive biological communities in water columns that could
be impacted by dispersed oil, chemical dispersants wou ;d not be appropriate for clean-up purposes.
Alternatively, chemical shoreiine-cleaning-agents or noi-surfactant-based solvents might be acceptable in such
situations if booming and skimming operations are feasible for recovery of oil released from substrate surfaces.
In the absence of appropriate circumstances for use of any of these chemical agents, alternative clean-up
strategies might be considered (e.g., mechanical clean-up, berm relocation, bioremediation, or no treatment).
39
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SECTION 6
SUMMARY AND RECOMMENDATIONS - LABORATORY STUDIES
Estimating cleaning perform:ince by chemical agents for oil on laboratory test-substrates will involve
interactions between variables including chemical and physical properties of oils and cleaning agents, methods
of application of cleaning agents to oil, the nature and characteristics of substrates, the source and turbulence of
wash water available for removal of treated oil from substrate surfaces, cleaning-agent-to-oil ratios, oii-to-wash-
water ratios, temperature, and salinity of the wash water. Extrapolation of results from cleaning-performance
studies in a laboratory to field situations must take into account additional variables including rapid changes that
occur in properties of oils with time (i.e., natural weathering), field application methods and logistics, the
variety of substrate types that will be encountered on a particular shoreline, ambient weather and meteorological
conditions, and local sea-state and shoreline conditions (wave height and energy, currents, storms, etc.). The
breadth of these variables make it unlikely that any single laboratory test will be completely suitable to quantify
performance of chemical cleaning agents for all possible environmental scenarios. Therefore, laboratory lest
results for evaluating cleaning performance among candidate agents should more realistically be utilized to
apply relative rankings to performances for different agents, including possible assignment of "pass/fail" criteria
to individual agents. However, detailed scientific studies and considerations will be required to define the latter
criteria.
Efforts for needed future research on shoreline cleaning agents in the laboratory could include th«
following.
o Adoption of a standardized laboratory testing procedure for evaluating cleaning-performance of agents
for removing oil from substrate surfaces.
o Evaluation of the effect of natural weathering processes on oil as it relates to the performance of cleaning
agents for releasing oil from surfaces (i.e., important for determining the window-of-opportunity during
which a cleaning agent can be effective for removing oil).
o Evaluation and validation of the effects of relevant environmental variables on the performance of
cleaning agents (e.g., substrate types and characteristics, cleaning agent-to-oil ratios, cleaning agent-to-
oil soak-times, wash water volumes, turbulence or mixing regimes, temperature, and salinity;
appreciation of effects of these variables will promote understanding of the mechanisms of action for
cleaning agents). :
o Development of acceptance criteria (i.e., "pass/fail") for effectiveness (and toxicity) for allowing a.
product to be listed as a cleaning agent on the National Contingency Plan Product Schedule.
o Development of toxicity tests using fauna and flora that could be impacted by chemical cleaning agents
in real-world situations.
j
Research studies with direct implications for use of chemical cleaning agents in field situations could include the
following.
o Implementing designs and application protocols for delivery systems for applying cleaning agents to
oiled surfaces in the field.
o Implementation of studies in intentional spills-of-opportunity in selected field situations (i.e., for which
sampling and analytical preparation can be pre-planned) to yield information on application and
performance of cleaning agents in environmentally relevant, real-world situations.
40
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SECTION?
tEFER
RENCES
American Petroleum Institute (API). 1992. API Shoreline Cleanup Experiment. Background paper made
available at the 1992 International Oil Spill R&D Forum, 1-4 June 1992, McLean, VA. 7 p.
Becker, K.W. and G.P. Lindblom. 1983. Performance evaluation of a new versatile oil spill dispersant. ElQfi.
1983 Oil Spill Conference. 28 Feb.-3 Mar. 1983, San Antonio, TX. American Petroleum Institute,
Washington, D.C. pp. 61-64.
Bobra, M. 1990. A study of the formation of water-in-oil emulsions. Proc. Thirteenth Arctic Marine Oil Spjj]
Program Technical Seminar. 6-8 June 1990, Edmonton. Alberta. Environment Canada, Ottawa, Ontario, pp.
87-117. • I
Bobra, M. and S.Callaghan. 1990. A Catalogue of Crude Oil and Oil Product Properties ( 1990 Version
Environment Canada Publication No. EE-125, Environment Canada, Ottawa, Ontario, Canada. 542 p.
Bobra. M. 1991. Water-in-oil emulsification: A physicochemical study. Proc. 1991 International Oil Spilt
Conference. 4-7 Mar. 1991, San Diego. CA. American Petroleum Institute, Washington, D.C. pp. 483-488.
Bridie, A.L., T.H. Wanders, W. Zegveld. and H.B. van der Heijde. 1980. Formation, prevention and breaking
of sea water in crude oil emulsions 'chocolate mousses'. Marine Pollution Bulletin. 11: 343-348.
Brochu, C, E. Pelletier, G. Caron, and J.E. Desnoyers
of synthetic surfactants. Oil & Chemical Pollution
Buist, I. A. and S.L. Ross. 1986/87. A study of chemicals to inhibit emulsification and promote dispersion of oil
spills. Oil & Chemical Pollution. 3: 485-503.
Buist, I., S. Potter. D. Mackay, and M. Charles. 1989
crude oil spills. Proc. 1989 Oil Spill Conference.
Institute, Washington, D.C. pp. 105-113.
Canevari, G.P. 1979. The restoration of oiled shorelines
Oil Spill Conference. American Petroleum Institue
1986/87. Dispersion of crude oil in seawater: The role
3:257-279.
Laboratory studies on the behavior and cleanup of waixy
3-16 Feb. 1989, San Antonio, TX. American Petroleum
by the proper use of chemical dispersants. Proc. 1979
, Washington, D.C. pp. 443-446.
Canevari, G.P. 1982. The formulation of an effective demulsifier for oil spill emulsions. Marine Pollution
BuJJeiin, 13:49-54.
Chianelli, R.R., T. Aczel, R.E. Bare, G.N. George, M.W. Genowitz, M.J. Grossman, C.E. Haith, F.J. Kaiser,
R.R. Lessard, R. Liotta, R.L. Mastracchio, V. Minak-Bernero, R.C. Prince, W.K. Robbins, E.I. Su'efel, J.B.
Wilkinson, S.M. Hinton, J.R. Bragg, S J. McMillen, and R.M. Atlas. 1991. Bioremediation technology
development and application to die Alaskan spill. Proc. 1991 International Oil Spill Conference. 4-7 Mai1.
1991, San Diego, CA. American Petroleum Institute, Washington, D.C. pp. 549-558.
Clark, R.C., Jr. and D.W. Brown. 1977. Petroleum: Properties and analyses in biotic and abiotic systems. In:
Effects of Petroleum on Arctic and Subarctic Marine Environments and Organisms. Volume I. Nature and
Fate of Petroleum. (Malins, D.C., ed.) Academic Press, Inc., New York. pp. 1-89.
41
-------
Clayton, J.R.. Jr., G.H. Farmer, J.R. Payne, G.D. McNabb, Jr., P.C. Harkins, J.S. Evans, N.P. Rottunda, C.R.
Phillips, and MJL. Evans. 1989. Effects of chemical dispersant agents on the behavior and retention of
spilled crude oil in a simulated strcambed channel. In: Oil Dispersants: New Ecological Approaches. ASTM
STP 1018. (Flaherty, L.M., ed.) American Society for Testing and Materials, Philadelphia, PA. pp. 4-24.
Clayton, J.R., Jr. and J.R. Payne. 1991. Update State-of-the-Art on Oil Spill Dispersants: Mechanisms of
Action and Factors Influencing Dispersant Performance with Emphasis on Laboratory Studies. Draft Final
Report to The U.S. Environmental Protection Agency, Office of Research and Development, Risk Reduction
Engineering Laboratory (RREL), Release Control Branch, 2890 Woodbridge Avenue (MS-104), Edison, NJ
and RREL, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (EPA Contract No. 68-C8-0062, Work
Assignment No. 2/3-38) from Science Applications International Corporation, 10260 Campus Point Drive
(MS 32 - Environmental), San Diego, CA 92121 (SAIC Project No. 01-0831-03-0317 and 01-0895-03-0991).
101 p.
Cormack, D.B., W.J. Lynch, and B.D. Dowsett. 1986/87. Evaluation of dispersant effectiveness. Oil &
Chemical Pollution. 3: 87-103.
Couillard, D. and F.T. Tran. 1989/90. Oil spill clean-up system using hot water. Journal of Environmental
Systems. 19(2): 135-153.
Crowley, S. and J. Nightingale. 1983. Evaluation of oil spill dispersant concentrates for beach cleaning. Report
No. LR 463 (OP)-M, Warren Spring Laboratory, Department of Trade and Industry. Stevenage,
Hertfordshire, England. 15 p.
Daling, P.S., P.J. Brandvik, D. Mackay, and O. Johansen. 1990. Characterization of crude oils for
environmental purposes. Proc. Thirteenth Arctic Marine Oil Spill Program Technical Seminar. 6-8 June
1990, Edmonton, Alberta. Environment Canada, Ottawa, Ontario, pp. 119-138.
Dennis, R.W. and B.L. Steelman. 1980. Overland aerial applications tests of oil spill dispersants held at
Abbotsford. B.C., March 13-14,1979. Technical Report, Exxon Research and Engineering Company,
Florham Park, N.J. i
Dewling, R.T. and C.C.D.A.E. Silva. 1979. Impact of dispersant use during the Brazilian Marina incident.
Proc. 1979 Oil Spill Conference. 19-22 Mar. 1979. American Petroleum Institute, Washington, D.C. pp.
269-276.
Farn, R.J. 1983. Sinking and dispersing oil. In: The Control of Oil Pollution. (J. Wardley-Smith, ed.) Graham
and Trounan Publishers, London, pp. 172-197.
Fingas, M.F., K.A. Hughes, and M.A. Schweitzer. 1987a. Dispersant testing at the Environmental Emerj$encies
Technology Division. Proc. Tenth Arctic Marine Oilspill Program Technical Seminar. 9-11 June 1987,
Edmonton, Alberta, Canada. Conservation and Protection, Environment Canada, pp. 343-356.
Fingas, M.F., M.A. Bobra, and R.K. Velicogna. 1987b. Laboratory studies on the chemical and natural
dispersibility of oil. Proc. 1987 Oil Spill Conference. American Petroleum Institute, Washington, D.C. pp.
241-246. ,
Fingas, M.F. 1988. Chemical treatment of oil spills, in; Alaska Arctic Offshore Oil Spill Response
Technology. Workshop Proceedings. Workshop sponsored by Minerals Management Service, U.S.
Department of Interior. 29 November-1 December 1988, Anchorage, Alaska. National Institute of
Standards and Technology Special Publication (NIST SP) 762. pp. 27-46.
42
-------
Fingas, M., G. Stoodley, G. Harris and A. Hsia. 1989.
at the Cleanup Technology Workshop, Anchorage,
Evaluation of chemical beach cleaners. Paper presented
AK, 28-30 November 1989. 5p.
Fingas, M.F., B. Kolokowski, and EJ Tennyson. 1 9901 Study of oil spill dispersants effectiveness and physical
studies. Proc. Thirteenth Arctic Marine Oil Spill Program Technical Seminar. 6-8 June 1990, Edmonton,
Alberta. Environment Canada, Ottawa, Ontario, ppi
Fiocco, R.J., G.P. Canevari, J.B. Wilkinson, H.O. Jahns
Development of Corexit 9580—A chemical beach c
265-287.
J. Bock, M. Robbins, and R.K. Markarian. 1991.
leaner. Proc. 1991 International Oil Spill Conference,, 4-
7 Mar. 1991, San Diego, C A. American Petroleum Institute, Washington, D.C. pp. 395-400
oil
Fiocco, R.J. 1991. A new chemical beach cleaner for oiled shorelines - Corexit 9580. Personal correspondence
from R.J. Fiocco (Environmental, Marine & Safety Division, Exxon Research and Engineering Company,
Florham Park, NJ) to J: Clayton (Science Applications International Corporation, San Diego, CA). 35 p.
Canning, B., D.J. Reish, and D. Straughan. 1984. Recovery and restoration of rocky shores, sandy beaches,
tidal fiats, and shallow subtidal bottoms impacted by oil spills. In: Restoration of Habitats Impacted by Oil
Spills. (Caims, J., Jr. and A.L. Buikema. Jr., eds.) Buuerworth Publishers, Boston, Massachusetts, pp. 7-36.
Holloway, M. and J. Horgan. 1991. Soiled shores. Scientific American. 265: 102-116.
Jahns, H.O., J.R. Bragg, L.C. Dash, and E.H. Owens. 11991. Natural cleaning of shorelines following the
EXXON VALDEZ spill. Proc. 1991 International Oil Spill Conference. 4-7 Mar. 1991, San Diego, CA.
American Petroleum Institute, Washington, D.C. pp. 167-176.
Jordan, R.E. and J.R. Payne. 1980. Fate and Weathering of Petroleum Spills in the Marine Environment. A
Literature Review and Synopsis. Ann Arbor Science Publishers, Inc., Ann Arbor, Michigan. 174 p.
Lindblom, G.P. and C.D. Barker. 1978. Evaluation of equipment for aerial spraying of oil dispersant
chemicals. In: Chemical Dispersants for the Control of Oil Spills. ASTM STP 659. (L.T. McCarthy, Jr.,
G.P. Lindblom, and H.F. Walter, eds.) American Society for Testing and Materials, Philadelphia, PA. pp.
169-179.
Lindblom, G.P. and B.S. Cashion. 1983. Operational considerations for optimum deposition efficiency in aerial
application of (oil spill) dispersants. Proc. 1983 Oil! Spill Conference. 28 Feb.-3 Mar. 1983, San Antonio,
TX. American Petroleum Institute, Washington, D.C. pp. 53-60.
Little, D.I., T.P. Abbiss, J.M. Baker, B.M. Dicks, and RJ.C. Tibbetts. 1986. The effect of chemical dispersants
on the flux of stranded crude oil into fine intertidal sand. Rapp. P.-v. Reun. Cons, int. Explor. Mer. 186:
219-233.
Little, D.I. and D.L. Scales. 1987. El'fectiveness of a Type III dispersant on low-energy shorelines. Proc. 1987
Oil Spill Conference. American Petroleum Institute, Washington, D.C. pp. 263-267.
Mackay, D., A. Watson, C. Ng, and S. Nadeau. 1979. Behavior and effectiveness of dispersants at sea and at
shorelines. Proc. 1979 Oil Spill Conference. 19-22
D.C. pp. 447-452. .
vlar. 1979. American Petroleum Institute, Washington,
43
-------
Mackay, D., A. Chau, K. Hossain, and M. Bobra. 1984. Measurement and prediction of the effectiveness of oil
spill chemical dispersants. In: Oil Spill Chemist Dispersams. Research Experience and Recommendations.
ASTM STP 840. (T.E. Alien, ed.) American Society for Testing and Materials, Philadelphia, PA. pp. 38-
54.
McAuliffe, C.D. 1989. The weathering of volatile hydrocarbons from crude oil slicks on water. Proc. 1989 Oil
Spill Conference. 13- 16 Feb. 1989, San Antonio, TX. American Petroleum Institute," Washington, D.C. pp.
357-363. :
Merlin, F. (undated) Cleaning Products, unpublished manuscript describing cleaning products and procedures
for treating stranded oil on shoreline surfaces by Centre de Documentation de Recherche et
d'Experirnentations sur les Pollutions Accidentelles des Eaux (CEDRE), Plouzane, France. 4 p,
Morris, P.R. and F. Martinelli. 1983. A specification for oil spill dispersants. Report No. LR 448 j(OP)-M,
Warren Spring Laboratory, Department of Trade and Industry, Stevenage, Hertfordshire, England. 7 p. and
two appendices.
Morris, P.R., J.F. Nightingale, D.H. Thomas, D.J. Tookey, and A.C. Turner. 1985. Beach cleaning trials: Cefn
Sidan sands 1984. Report No. LR 527 (OP)-M, Warren Spring Laboratory, Department of Trade and
Industry, Stevenage, Hertfordshire, England. 39 p. and four appendices.
Morris, P.R. and D.H. Thomas. 1988. Evaluation of oil spill dispersant concentrates for beach cleaning - 1987
trials. Report No. LR 624 (OP), Warren Spring Laboratory, Department of Trade and Industry, Stevenage,
Hertfordshire, England. 25 p.
NRC (National Research Council). 1985. Oil in the Sea: Inputs. Fates and Effects. National Research Council.
National Academy Press, Washington, D.C. 601 p.
Nauman, S.A. 1990. Shoreline clean-up techniques - EXXON VALDEZ operations. Prog. Thirteenth AJCUC
Marine Oil Spill Program Technical Seminar. 6-8 June 1990, Edmonton, Alberta. Environment Canada,
Ottawa, Ontario, pp. 431-438. .
Nauman, S.A. 1991. Shoreline cleanup: equipment and operations. Proc. 1991 In.ternati9n.at Oil Spill
Conference. 4-7 Mar. 1991, San Diego, CA. American Petroleum Institute, Washington, D.C. pp. 141-147.
Nelson-Smith, A. 1978. Effects of dispersant use on shore life, in; Chemical Dispersants for the ControLoLQil
Spills, AS™ STP 659. (L.T. McCarthy, Jr., G.P. Lindblom, and H.F. Walter, eds.) American Society for
Testing and Materials, Philadelphia, PA. pp. 253-265.
Nightingale, J.F. and D.T. Thomas. 1984. Evaluation of oil spill dispersant concentrates for beach cleaning -
1984 trials. Report No. LR 507 (OP)-M, Warren Spring Laboratory, Department of Trade and Industry,
Stevenage, Hertfordshire, England. 21 p.
North, A.A., D.H. Thomas, A.C. Turner, and T. Walsh. 1988. Beach cleaning trials: Newhaven 1988. Report
No. LR 690 (OP), Warren Spring Laboratory, Department of Trade and Industry, Stevenage, Hertfordshire,
England. 40 p. and two appendices.
Owen D. 1991. Bioremediation of marine oil spills: Scientific validity and operational constraints.
Fnnrr^mh Arctic Marine Oil SoiH Prnyran, Technical Seminar. 12-14 June 1991, Vancouver, British
Columbia. Environment Canada, Ottawa, Ontario, pp. 119-130. ;
44
-------
Owens, E.H. and W. Robson. 1987. Experimental design and the retention of oil on Arctic test beaches.
Arctic., 40 (supp. 1): 230-243.
Owens, E.H., W. Robson, and C.R. Foget. 1987. A fie
Arctic. 40 (supp. 1): 244-257.
I
!d evaluation of selected beach-cleaning techniques.
Owens, E.H., A.R. Teal, and P.C. Haase. 1991. Berm eiocation during the 1990 shoreline cleanup program
following the "EXXQN VALDEZ' spill. Proc. Fourteenth Arctic Marine Oil Spill Program Technical
Seminar. 12-14 June 1991. Vancouver, British Columbia. Environment Canada. Ottawa, Ontario, pp. 607-
630.
Payne, J.R., B.E. Kirstein, G.D. McNabb, Jr., J.L. Lambach, C. de Oliveira, R.E. Jordan, and W. Horn. 1983.
Multivariate analysis of petroleum hydrocarbon weathering in the subarctic marine environment. Proc. 1983
Oil Spill Conference. 28 Feb.-3 Mar. 1983, San Antianio, TX. American Petroleum Institute, Washington,
D.C. pp. 423^34.
Payne, J.R., B.E. Kirstein, G.D. McNabb, Jr., J.L. Lam )ach, R. Redding, R.E. Jordan, W. Horn, C. de Oliveira,
G.S. Smith, D.M. Baxter, and R. Geagei. 1984. Multivariate analysis of petroleum weathering in the marine
environment—Subarctic. Vol. I and II. In: Environmental Assessment of the Alaskan Continental Shelf,
Final Reports of Principal Investigators. NOAA, OCSEAP Final Reports 21 and 22 (1984). U.S.
Department of Commerce, Washington. D.C. 690 ]
Payne, J.R. and G.D. McNabb, Jr. 1984. Weathering of petroleum in the marine environment. Journal of the
Marine Technology Society. 18(3): 24-42.
Payne, J.R. and G.R. Phillips. 1985. Petroleum Spills in the Marine Environment. The Chemistry and
Formation of Water-in-Oil Emulsions and Tar Balls. Lewis Publishers, Inc., Chelsea, Michigan, USDA, 148
P-
Payne, J.R., J.R. Clayton, Jr., G.D. McNabb, Jr., and B
E. Kirstein. 1991. Exxon Valdez oil weathering fate
and behavior Model predictions and field observations. Proc. 1991 International Oil Spill Conference. 4-7
Mar. 1991, San Diego, CA. American Petroleum Institute, Washington, D.C. pp. 641-654.
Pritchard, P.H. and C.F. Costa. 1991. EPA's Alaska oil spill bioremediation project. Environmental Science
and Technology. 25: 372-379.
Smedley, J.B. 1981. The assessment of aerial application of oil spill dispersants. Proc. 1981 Oil Spill
Conference. 2-5 Mar. 1981, Atlanta, GA. American Petroleum Institute, Washington, D.C. pp. 253-257.
Southward, AJ. and E.C. Southward. 1978. Recolonization of rocky shores in Cornwall after use of toxic
dispersants to clean up the TORREY CANYON spi 1. J. Fisheries Research Board of Canada. 35: 682-706.
Tabak, H.H., J.R. Haines, A.D. Venosa, J.A. Glaser, S. Desai, and W. Nisamaneepong. 1991. Enhancement of
biodegradation of Alaskan weathered crude oil components by indigenous microbiota with the use of
fertilizers and nutrients. Proc. 1991 International Oil Spill Conference. 4-7 Mar. 1991, San Diego, CA.
American Petroleum Institute, Washington, D.C. pp. 583-590.
Turner, A.C., A.A. North, A. Craig, K. Colcomb-Heiliger, M. Sommerville, T. Walsh, and D. Tookey. 1989.
Beach cleaning trials: Newhaven 1989. Report No'f LR 761 (MPBM), Warren Spring Laboratory,
Department of Trade and Industry, Stevenage, Hertfordshire, England. 71 p. and one appendix.
45
-------
Venosa, A.D., J.R. Haines, W. Nisamaneepong, R. Govind, S. Pradhan, and B. Siddique. 1991. Protocol for
testing bioremediation products against weathered Alaskan crude oil. Proc. 1991 International Oil Spill
Conference. 4-7 Mar. 1991, San Diego, CA. American Petroleum Institute, Washington, D.C. pp. 563-570.
Webb, M. and A.C. Turner. 1991. Beach cleaning trials: Newhaven 1989. Proc. 1991 International Oil Spill
Conference. 4-7 Mar. 1991, San Diego, CA. American Petroleum Institute, Washington, D.C. pp. 153-160.
Wells, P.G., S. Abemathy, and D. Mackay. 1985. Acute toxicity of solvents and surfactants of dispersants to
two planktonic crustaceans. Proc. Eighth Annual Arctic Marine Oilspill Program Technical Seminar. 18-20
June 1985, Edmonton, Alberta, Canada. Environmental Protection Service, Environment Canada, pp. 228-
240. '
46 .
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APPENDIX A
PREPARATION APPROACH FOR THIS REPORT
This report has been prepared to update information for the mechanism of action of chemical shoreline-
cleaning-agents for oil spills, variables affecting performance of such agents, evaluations of laboratory tests for
assessing performance, and brief consideration of the relevance of laboratory test results to spills in field
situations. The approach taken for obtaining the information for the report has been twofold: (1) thorough
searches were conducted in the available scientific literature and (2) direct input from an international body of
experts on the relevant subjects was invited and. incorporated. In addition to input from and discussions with the
individuals, drafts of this report have been subjected to critical review and comment by qualified individuals
internal and external to the U.S. EPA. Particular appreciation is expressed by the author to the following
individuals for constructive input to drafts of the report: Gerard P. Canevari, Robert T. Drew, John S. Farlow,
Mervin F. Fingas, Robert Fiocco, Richard G. Griffiths, Robert R. Hiltabrand, Ed Levine, Francois Merlin, Royal
Nadeau, Choudhry Sarwar, Matthew Sommerville, Daniel Sullivan, and Maurice Webb. All comments and
suggestions from the preceding individuals were given careful consideration and, wherever possible, appropriate
adjustments were made to the content of the report. Addresses for these individuals are included below:
Gerard P. Canevari I
G.P. Canevari Associates
104 Central Avenue
Cranford,NJ 07016
Robert T. Drew
American Petroleum Institute
1220 L Street, Northwest
Washington, DC 20005
Mervin F. Fingas
Emergencies Science Division
Environment Canada
River Road Environmental Technology Centre
Ottawa. Ontario K1A OH3
CANADA
Robert Fiocco
Exxon Research & Engineering Co.
P.O. Box 101
Florham Park, NJ 07932
Richard G. Griffiths
RCB.RREL
U.S.EPA
2890 Woodbridge Avenue
Edison, NJ 08837-3679
Robert R. Hiltabrand
U.S. Coast Guard R&D Center
Avery Point
Groton. CT 06340-6096
47
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EdLevihe
Hazardous Materials Response and Assessment Division
National Oceanic and Atmospheric Administration
U.S. Department of Commerce
Building 110, Box 2
Governors Island, NY 10004
Francois Merlin
CEDRE
BJ?. 72, Pointe du Diable
29280 Plouzane
FRANCE
Royal Nadeau
Emergency Response Division
U.S. EPA. Building 18 (MS-101)
2890 Woodbridge Avenue
Edison, NJ 08837-3679
Choudhry Sarwar
RCB.RREL
U.S.EPA(MS-106)
2890 Woodbridge Avenue
Edison, NJ 08837-3679
Matthew Sommerville
Warren Springs Laboratory
Gunnels Wood Road
Stevenage, Hertfordshire SGI 2BX
UNITED KINGDOM
Daniel Sullivan
RCB.RREL
U.S.EPA(MS-106)
2890 Woodbridge Avenue
Edison, NJ 08837-3679
Maurice Webb
Warren Spring Laboratory
Gunnels Wood Road
Stevenage, Hertfordshire SGI 2BX
UNITED KINGDOM
*Q -&U.S. GOVERNMENT PRINTING OFFICE: 1993 - 7SO-OD2/8024S
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