WATER POLLUTION CONTROL RESEARCH SERIES • ORD-3
    Chemical Treatment of Oil Slicks
U.S. DEPARTMENT OF THE INTERIOR • FEDERAL WATER POLLUTION CONTROL ADMINISTRATION

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            CHEMICAL TREATMENT OF




                  OIL SLICKS
                A STATUS REPORT




       ON THE USE OF CHEMICALS AND OTHER




     MATERIALS TO TREAT OIL SPILLED ON WATER
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION




          DEPARTMENT OF THE INTERIOR




                      BY




           WATER QUALITY LABORATORY




               NORTHEAST REGION




           EDISON, NEW JERSEY  08817









                  MAHCH 1969

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                              ABSTRACT






The effectiveness and potential pollutional effects of chemicals and other




materials used to disperse, sink,.burn or otherwise dissipate oil slicks




are discussed.






Agents considered are classed as; dispersants, floating sorbents, sinking




agents, gelling agents and burning agents.






Since many dispersants are presently available, much experience has




been gained with the use of dispersants.  However, dispersants should




not be used indiscriminately, they may have deleterious effects on the




ecology.  It is necessary to determine the toxicity and the effectiveness




of dispersants viz-a-viz the same characteristics of the oil -without




dispersants.  Practical experience', with gelling  burning, floating and




sinking agents is limited;"






Some of the many commercial' products' and".natural materials used in




connection with recent large-Soil spills'-'are reported.






KEY WORDS:  Oil spills, oil spills-chemical treatment, dispersants,




            detergents, sorbents, floating sorbents, burning agents,




            sinking agents, gelling agents, dispersant toxicity,




            dispersant effectiveness chemical use, effects.

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                    CONTENTS









  I.  Introduction	11




 II.  Summary	1




III.  Sections




         Dispersants 	  5




         Floating Sorbents 	 10




         Sinking Agents	14




         Gelling Agents	17




         Burning Agents	18
                         ill

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                               INTRODUCTION







The disastrous effects of significant oil spills into the water environ-




ment, together with required remedial measures, are described in "Gil




Pollution: A Report to the Presidentt" submitted early in 1968.  Chemical




compounds are intended to assist in the control of oil on the water and




facilitate cleanup operation.  Basically, chemicals are employed to dis-




perse, gel, sink, absorb, and facilitate the burning of oil.  Present




knowledge has resulted primarily from experience with the major spills




from the tankers TORREY CANYON and OCEAN EAGLE and the offshore oil




platform at Santa Barbara, California.  In addition, the FWPCA is gaining




valuable experience through giving technical assistance on actual spill




incidents and is conducting broad research and development programs




relating to the cleanup and control of oil in the water environment.







With the exceptidn of gelling agents, chemicals have been used during




the three major incidents, singly and in combination, with varying




results.  Each major incident differed as to causes and immediate control




of the sources of oil, the type and use of the water environment, and




the nature and proximity of the shoreface.  The resulting damage has




been waterfowl fatalities, deposition of oil upon recreational beaches,




and adverse effects to marine life.

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                                 SUMMARY






This report provides a statement by the Research Program of the FWPCA




on the use of various chemicals to treat oil on water.  Basically,




methods employed are designed to disperse, absorb, sink, gel, and




facilitate burning of oil on the water surface and affected shorelines.




A number of factors must be carefully evaluated in the use of chemicals




most important of which are toxicity and overall effects upon the water




environment, effectiveness of the methods utilized, and cost of obtain-




ing and applying chemicals together with recovery and disposal operations.






Dispersants theoretically serve to increase the surface area of an oil




slick and disperse oil globules throughout the larger volume of water




thereby aiding in accelerated degradation of oils by microbiological




means.  The chemical dispersants do not themselves destroy oil.  They vary




considerably in toxicity, effectiveness and ability to stabilize the oil




after extended periods of time.  Technology for proper application of




dispersants over large oil slicks with necessary mixing is currently




lacking.  Use appears far more critical in harbor and estuary areas and




in proximity to shore.  Particular care must be exercised where water supply




might be affected.  The desirability of employing dispersants in the open




sea remains doubtful although their use here is potentially more promising




pending additional field data.  After widespread dispersant use, reports




led to the conclusion that dispersants on the dispersant-oil mixture cause




much more damage to aquatic life than oil alone.  For beaches, they actually




compound the problem by adding to the amount of pollutants present, by

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causing the oil to penetrate more deeply into the sand, and by disturbing




the sand's compactness, so as to increase beach erosion through tidal and




wave action.






Floating absorbents include a wide range of materials with oil-attracting




and water-repelling characteristics.  Absorbents have unique advantages




over other methods of oil cleanup, such as limiting the rate of slick




spreading or facilitating cleanup, but it also has a number of disadvan-




tages including delivery and application of the material, and collection




and disposal of the oil-absorbent mass.  Straw is extensively used as an




absorbent because of availability, cheapness and accepted effectiveness;




large investment in equipment and manual labor for removal of oil soaked




straw is however required.  Natural products or those modified by heat and




chemical treatment are currently used as absorbents.  An additional group




of absorbent products, which hold potential promise, are those derived




from the synthetic or plastic manufacturing field; of these, polyurethane




and polypropylene are in greatest use.  Considerable mixing or interac-




tion between the oil and the absorbent is very desirable for maximum




uptake of oil.  Absorbent application and their overall use become




increasingly complex with the larger oil spills.  Collection and disposal




of the oily mass poses greater problems than disposal of oil-water




emulsions due to the relatively large bulk and due to the lack of disposal




techniques that can handle the conglomerate.






Sinking agents properly applied onto an oil slick adhere to the oil, and




there is subsequent absorption and sinking of the oily mass.  Sinking




absorbents should be evenly mixed with the slick and allowed time to react




before the mass eventually sinks.  For optimum effectiveness, there should




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also be little or no tendency for release of the oils back to the water

environment.  Care should be exercised in its use as the oil mass can form

a layer 'or "blanket" on the bottom causing adverse effects on fixed shell-

fish beds and bottom feeding organisms.  The only large-scale use of

sinkants was that made by the French following the TORREY CANYON.  Opinion

is still divided as to efficency, cost, application, and possible environ-

mental effects.  It appears the utilization of sinking agents would be

most advantageous in deeper ocean waters outside the heavier fishing zones
                        minimum
and where there will be /adverse effects to productive biological life in

the coastal zones.


Gelling agents applied over the surface or periphery of an oil slick show

promise as another approach for containing and cleaning up oil spills.

The gelled mass would still require removal from the water surface perhaps

with specialized equipment developed for that purpose.  Further development

is necessary for this class of chemicals.


Burning agents offer an attractive and inexpensive means of disposing of

large amounts of oil over the water surface.  This course of action is

inadvisable except in situations where the oil is sufficiently distant

from the shoreline or other property subject to fire damage.  Past attempts

to burn oil have been largely unsuccessful due to the fact that the light

ends of the oil usually are no longer present, raising the flame temperature,

plus the ability of the water to remove the heat faster than it can be

created.  Because of the potential value of this method, however, further

consideration should be given for improving and refining these procedures.


In considering the use of chemicals with oil spills, a number of factors

muse be carefully borne in mind.  Of prime importance is the effect of

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the chemical or oil-chemical mixture on the water environment.  The intro-




cution of toxic chemicals in the water or on the shoreface can destroy the




delicate balance of aquatic ecology and result in long-lasting damage or




destruction of valuable species intended to be protected by the removal of




the oil.  The ability of the chemicals to accomplish the assigned task is




a critical factor.  The type of oil involved, the physical and chemical




nature of the water body, and the particular products used will relate to




the effectiveness of the method.  In major incidents involving spills of




oil, the cost of obtaining and applying chemicals may range into millions




of dollars.






The purpose  of oil removal is not to eliminate its visibility but to mini-




mize its effects upon water shore and near shore resources.  The most




effective means for eliminating visible oil could destroy the very resources




intended to  be protected; conversely, the most visible and tedious means




for removal  can be the most effective in resource protection.  The objective




of adequate  oil pollution control is to minimize the removal and minimize




the short and long range adverse effect.

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                              DISPERSANTS






Scores of products are sold in this country for the purpose of emulsify-




ing oils.  Many have been developed for such us is as clearing residual




oil from cargo tanks before loading of fresh cargo.  Of these, at least




70 have been claimed useful for dispersing oil from the surface of water.




These products are known by a variety of names: emulsifiers, detergents,




degreasers, dispersants, etc.  For consistency, they will be referred to




as dispersants since this term describes what they are intended to




accomplish - the dispersion of oil from the surface into and throughout




the body of water.






The primary components in most dispersants are surfactants, solvents, and




stabilizers.  Surfactants, by their affinity for both oil and water, alter




the interaction between oil and water so the oil tends to spread and can




be more easily dispersed into small globules - or what is commonly called




an emulsion.  Soap does the same thing to oil on our hands, allowing it




to b.e emulsified or dispersed and washed away in water.






Solvents enable the active agent or surfactant, to mix with and penetrate




into the oil slick and thusly form the emulsion.  The solvent usually




comprises the bulk of the dispersant product and may range from petroleum




solvents such as kerosene to water solvents.  Petroleum based and




chlorinated hydrocarbon solvents represent the most toxic component in




the dispersant product but also dissipate rapidly in the\ater environment.




Stabilizers,which are the third major component in most dispersants,




fix the emulation once it is formed.

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The use of dispersants in oil pollution incidents is intended to separate




the slick into miniscule particles and thus provide a means of accelerat-




ing the rate of natural degradation of oil.  We know that oil is degraded




naturally at sea at a rate depending upon the surface area of the oil




available to the microorganism populations.  Increasing the surface area




of the oil by dispersion is thought to accelerate this biological degra-




dation.






Dispersants have been used for a number of years, for dispersing small




oil slicks in several harbors in this country and abroad.  Because of the




small quantities involved, the environmental effects were minimal and the




complaints limited.  Few alternatives exist.for handling oil spills and




dispersants are easily obtained, transported and applied.  They further-




more offer visible evidence of "doing something" about pollution incidents.






Their first major test came during the TORREY CANYON incident where 15,000




tons of dispersants were used to treat 75,000 tons of oil.  Two-thirds of




this amount was used for cleaning oil from contaminated shores and resulted




in severe adverse effects on the aquatic life.  The areas of the shore




where dispersants were not used, but heavily polluted with oil alone,




showed very minor damage according to J. E. Smith, Director of the




Plymouth Laboratory of the Marine Biological Association of the United




Kingdom, who studied the biological effects of the TORREY CANYON spill.




These observations led to the conclusion that dispersants cause much more




damage to aquatic life than oil alone.

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The dispersants used during the TORREY CANYON incident were mostly solvent-

based and highly toxic, killing marine organisms at concentrations around

10 parts per million.

The biological damage during the TORREY CANYON appeared to be limited to

the shore areas.  In the open sea where they were also used, there were

no detectable effects on. marine life.  Officials from the United Kingdom

took samples by trawling directly beneath slicks treated with emulsifiers

and observed no deaths and no tainting of the flavor of commercial species.

Procedures for this type of sampling are not notably precise, however.

Current information indicates that dispersants vary considerably in

toxicity.  Various reports state that dispersants used during the TORREY

CANYON incident were highly toxic.  Since then, other less toxic dis-

persants have been developed.  Fifty percent of marine test fish are

killed within 24 hours by exposure to concentrations as low as 4 parts per

million of one product, and as high as 10,000 parts per million of another.

Moreover, the combination of oil and dispersant may conceivably increase

the toxicity of either the oil, the dispersant chemical, or both.  The

possibility of this "synergistic" action must be carefully examined before

wholesale and widespread use of dispersants is permitted.  Dispersing the

oil (which is toxic) may also compound the damage.

But toxicity is not the only consideration in the use of dispersants.  Of

equal significance is their effectiveness.  Experience at San Juan, Puerto

Rico, and field tests conducted by research personnel at Edison, N.Y.,

indicate that they are generally ineffective for cleaning oil from beach

sand of the ty.pe found along our east coast.  They actually compound the
problem by adding to the amount of pollutants present and by causing the
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oil to prenetrate more deeply Into the sand.  The "TORREY CANYON Pollution




and Marine Life" report also noted that "quicksand," occurred as the result




of using these materials, resulting in beach erosion from tidal and wave




action.






Evaluation of the effectiveness of dispersants on water is much more




difficult in cases of accidental spills.  Lack of adequate methods for




measuring the amount of oil on water and the rate of natural dispersion




make precise evaluation difficult.  Their effectiveness during the TORREY




CANYON is still being debated.  Subsequent incidents which are claimed to




have demonstrated their effectiveness have been at remote locations and




without'impartial, qualified observers.  Application methods of disper-




sants and subsequent agitation, which are critical for effective performance,




have not always been optimal.






The cost of dispersants ranges from two to four dollars per gallon.




Using recommended doses, the cost of chemicals for dispersing a relatively




small 500 barrel spill would be about $20,000.  The cost for chemicals




used on the TORREY CANYON oil exceeded $5 million.  Adequate technology




for their massive application to major spills is lacking.  Slicks from




large spills spread in micro-thin layers over hundreds of square miles .




Efficient use of dispersants to treat a complete slick would require




proper density application and agitation of large areas of the sea surface.




Sbch methods and the required scale of equipment have not been developed.






Thus, the desirability of using dispersants on the open sea remains




unresolved.  The FWPCA is conducting research to help provide the




answers.  As an initial step an interim standard procedure has been




developed for measuring 'Che comparative acute tbxicity of dispersants




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to selected aquatic organisms.  This will allow the assessment of




relative toxicity among equally effective dispersants.  We are continu-




ing Nto refine this procedure and refine our capability for predicting




the effect of dispersants on the water and near shore environment.  Our




research personnel are also developing a standard tes't for measuring the




effectiveness of dispersants, so they may be rated on. a common basis.

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                        DEPARTMENT OF THE  INTERIOR

              FEDERAL WATER POLLUTION CONTROL ADMINISTRATION

                           POLICY ON THE USE OF

                     CHEMICALS TO TREAT FLOATING  OILS
1.  Chemicals should not be used to emulsify,  disperse,  solubillze, or
    precipitate oil  whenever the'protection  or preservation  of  (a) fresh
    water supply sources, (b) major shellfish  or fin  fish  nurseries,
    harvesting grounds or passage areas, or  (c) beaches  is a prime concern.

    Such chemicals should only be used in those surface  water areas and
    under those circumstances where preservation and  protection of water
    related natural  resources is judged not  to be the highest priority or
    where a choice as to resource preservation may make  the  use of such
    materials a necessary alternative.

2.  Examples of areas and circumstances where  the use of such chemicals
    might be acceptable are:

    a.  where fire or safety hazards are presented by the  spill of a
        petroleiw product;

    b,  where large numbers of waterfowl may perish because  of the
        proximity of floating oil;

    c.  under certain conditions, as a "polishing" or final  clean-up of
        light slicks of oil following mechanical removal of  floating oils.

3.  Chemicals that emulsify, disperse, solubilize or  precipitate oil
    should be used only unrler the immediate  supervision  of the Federal
    Water Pollution Control Administration except where  it is judged
    that fire or safety hazards require the  immediate application of such
    chemicals.

4.  When chemical compounds are used in connection with  oil  clean-up* only
    those compounds exhibiting minimum toxicity toward the aquatic flora
    and fauna should be used.  The Federal Water Pollution Control
    Administration 1s now developing and will  soon issue a standard
    procedure for determining the toxicity of  such chemicals.

5.  Materials which aid in the collection of floating oils such as sorbents,
    gel1 ants and viscosity control additives are considered  to be generally
    acceptable providing that these materials  do not  in  themselves or in
    combination with the oil increase the pollution hazard.

6.  Research and development to improve chemicals which  emulsify, disperse*
    solubillze or precipitate oil 1s encouraged.  Whenever it is demon-
    strated to the complete satisfaction of  the Federal  Water Pollution
    Control Administration, that such a chemical, by  itself  and in combina-
    tion with oil 1s non-toxic its use may be  approved in  the areas where
    the protection or preservation of a) fresh water  supply  sources, or
    b) major shellfish or fin fish nurseries,  harvesting grounds or passage
    areas 1s a prime concern.

    July 5, 1968

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                       FLOATING SORBENTS



Absorbent is a broad term defining in this report a type of material




used in oil pollution control and clean-up.  Most absorbents are de-




scribed as oil-attracting (oleophilic) and water-repelling (hydrophobia).




The use of absorbents requires placement in the oil slick, attraction




of the oil to this material, and subsequent removal and disposal of the




resulting oily materials.  Such materials include straw, hay, sawdust,




rope, sisal, tree bark, peat moss, perlite, vermiculite, talc, pumice,




various clays, sea weed, kelp, chrome leather wastes, rock wool sheets,




glass wool, rayon floss, polymer beads and copolymers, polyurethane and




polypropylene sheets, fibers and foam, rubber or latex, and cotton or




textile wastes.  Any of the above materials may also be specially




treated in one or more ways to improve its absorbtive properties and




handling characteristics.  Furthermore, these materials may be used




as integrallpart of oil recovery-pickup devices, booming systems, beach




clean-up methods and other.






Absorbents are advantageous in that they generally do not add materials




in solution and thereby contribute to the existing problem.   They are



also capable  of picking up oils in large ratio to the amount of absorbent




usedo  Major  difficulties, particularly for large-scale spills, are in




calculating and delivering sufficient absorbent in the proper form at




the proper place and time, applying the materials over the water body,




adequately collecting and transporting the oil-soaked mass to shore,




recovering the oil  and  securing ultimate disposal of the mass.  Fire




hazard may also be  increased  by use of many of these materials in




confined places if  ignition sources are present.




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Many absorbents have performed quite well, particularly in small-scale




spills, and may have high potential for moderate and even large-scale



spills.  Toxicity is far less a problem than with dispersants since



the absorbent material generally remains in solid state; however,



certain absorbent products may need further evaluation in this respect.



Comparison of the relative effectiveness between various products



together with relative cost is presently lacking.  Evaluation must be



conducted both within the laboratory and under realistic field conditions.



The FWPCA Research facility has initiated limited studies in this direction.








Straw is widely used as an oil absorbent because of ready availability,



cheapness and accepted effectiveness.  It can be distributed manually



or mechanically with or without shredding.  Straw is most effective



when used on shore or close to shore.  Although straw can be effective



in clean-up it must be adequately worked into the oil and its retrieval



and disposal is a dirty, slow and tedious job, requiring equipment and



considerable manual labor.  In certain areas, soaked straw may not be



burned because of air pollution codes and may not be buried because of




potential groundwater pollution.
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Far less use has been made of other absorbents compared to straw.  Con-



cerning natural absorbents, sea weed, kelp and indigenous grasses have




been capable of absorbing apprecialble oil in the TORREY CANYON, OCEAN



EAGLE and Santa Barbara incidents.  Production of powdered pine bark



has been initiated by a Swedish pulp and papei mill.  It is reported



that two pounds of bark will absorb about one gallon of oil with in-




dicated costs around |5 per 33 pound bag of powdered bark.  Pre-



liminary data received from Sweden on peat moss show about two pounds



of absorbent required per gallon of oil.






Natural products can be heated or chemically treated to provide modified




materials for oil pollution control.  Perlite, a naturally occurring



volcanic rock receiving subsequent pulverization and thermal expansion,



has received favorable reports in aiding oil recovery on San Juan beaches;



however, its action was less certain in Santa Barbara and in FWPCA



research studies conducted on New Jersey beaches in 1968.  Cost is



approximately $75.00 per 100 cubic feet of absorbent.  Vermiculite after



treatment to render it expandable and hydrophobic has received mixed



reports in its ability to absorb oil.  Certain vermiculite products



are reported to rapidly absorb floating oils whereas others do not have



the required affinity.






Absorbents derived from synthetics or plastics represent an additional



group of products with potential promise.  These materials are generally



high-molecular weight polymers or polyethylene, polystyrene,  polypropylene




and polyurethane.   These agents may be applied as a light foam or plastic
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network by spraying, as a solid-state in. the form of pillows, sausage



shapes, or otherwise shredded and distributed over the oil slick.  It




is reported in theoretical terms that polyurethane foam can ultimately



absorb over 90 percent of its own  volume of oil or 100 times its own



weight.  Polypropylene is also reported as abjorbing six times its weight



in oil with one cubic yard capable of retaining 100 pounds of oil.  These



data represent extremely low cost to clean-up large volumes of oil but



such figures likely reflect laboratory conditions which can be far



different from those experienced in the field.  Difficulties have been



experienced with absorbing heavy and weathered oils.  Effectiveness



appears dependent upon prolonged time interaction, temperature, and other



factors which must be better understood before many of the observed



limitations can be overcome.






No absorbent appears truly effective when merely distributed over the



oil slick.  Agitation and increased interaction between the oil and the



absorbent is necessary whether induced by natural wind, wave or tidal



forces or by mechanical means.  Absorbent application becomes increasingly



complex with the larger oil spills.  In massive oil spills, the logistics



and equipment required to acquire and properly apply sufficient amounts



of absorbents and the consequent collection and disposal of the resultant



oily mass, become enormous due to the sheer bulk of the conglomerate and



the lack of adequate methods for handling and disposal.
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                           SINKING AGENTS




Sinking agents are granular solids of high density and generally of fine



structure.  When applied over the surface of a slick, they adhere to the



oil, absorb it and ultimately sink.  Typical oil-sinking agents include




sand, brick dust, fly ash, slaked lime, stucco, cement, china dust, omya



clay, vlocanic ash, chalk, crushed stone, coal dust and specially-produced




materials such as carbonized-siliconized-waxed sands and fly ash.






Sinking agents can be efficiently employed on thick heavy or weathered oil



slicks.  If the oil is widely dispersed on the surface in disassociated



masses, quantities of materials required are prohibitive.  It is doubtful



that sinkants may be profitably used with thin films and light crudes.



The absorbent must be evenly mixed with the slick and have proper time



for interaction before the ensuing mass eventually sinks.  Furthermore,



bonding of the agent with the oil must be nearly permanent; or else



there will be eventual release of the entrapped and sunken oils back



to the water environment.





The single known large-scale application of sinking agents was undertaken




by the French during the TOKREY CANYON incident.  Some 3,000 tons of



calcium carbonate with about one percent of sodium stearate added were



reportedly  used   to treat and sink about 20,000 tons of oil found in




the Bay of Biscay and originating from the TORREY CANYON.  Although good



scientific data are generally lacking particularly as to the precise




amount of oil acutally treated, the oils were reported sunk in 60-70




fathoms and coastal pollution was minimized.  The French success was
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attributed to good spreading and mixing of the chalk into the oil body



and the high density of the weathered slick, thereby requiring considerably



less absorbent as compared to fresher oils.  Subsequent reports state




that 14 months after the incident no sign of oil was found over the water



surface.  On the basis of French 'experiences above, oil-sinking agents




have subsequently become more attractive and promising.






Opinions on the use of oil sinkants still remain divided as to efficiency,



cost, application and detrimental environmental effects.  Advantages of



this type of treatment are that it tends to confine the spilled oil and



the concommitant damage to a fixed place on the sea and probably minimizes



toxicity to free floating plants and animals.  Opposition to these agents



are ascribed to the potential damage to sea bottom life, the problems



associated with transporting and properly applying large amounts of the



agents to the oil slicks plus the possibility of the oil resurfacing



following biological degradation of the conglomerate.





Economics of this treatment method varies widely because practically all



data have been obtained from laboratory testing rather than from application



under field conditions.  Early Department of Interior studies suggest three



pounds of carbonized sand are required to sink one pound of oil whereas



other studies indicate ratios of one or less of sinker weight to oil weight,



depending upon density of oil slick and other factors.  Large-scale



application generally envisions spraying a slurry of sand or other mixture
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over the slick from a large vessel, hopper dredge, or equivalent.  The



cost of sinking agents is generally in the range of §20 to $80 per ton,




depending upon quantity purchased, and location and type of material



required.






The use of sinking agents would be most advantageous in deeper ocean




waters outside the heavy-fishing zones.  If resurfacing of the oils



does occur, it should be gradual and far less objectionable in the



event weathered oils were washed ashore at a later time.
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                           GELLING AGENTS.






The use of special gelling or congealing materials applied over the sur-



face or periphery of an oil slick is another approach for containing and



cleaning up oil spills.  The gelling concept is also in the process of




development for stabilizing liquid cargo aboard a stranded or heavily-



damaged vessel at sea.






One patented product when applied in spray form, is reported to form a




stiff gel with oil on water.  When placed around the perimeter of an oil



slick, the gel is said to form an effective chemical boom which prevents




the oil from further spreading.  The oil contained within the inner circle



may be removed by mechanical means or the total slick may be gelled to



facilitate removal.  The developers also claimed that the oils recovered in



this manner may be profitably reclaimed.  For example, the gelled mass



may be mixed with fuel oil and burned as replacement bunker fuel.






Possible toxicity of this class of chemical is unknown but under current




evaluation.  Data from the manufacturer indicate approximately one part



chemical is necessary per part of oil to be gelled, thereby givijag an esti-



mated cost of about $1.50 per gallon oil treated.  However, these costs



very likely reflect laboratory testing and assuredly would be lower then



for field application.
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                          BURNING AGENTS





The concept of setting afire oils which have spilled and spread over the




surface of a-water body is potentially attractive principally because



this appears to offer an inexpensive means of disposing of the problem.



Past attempts to burn oils upon the sea have been almost completely unsuc-



cessful, especially in the case of the TOEREY CANYON.  There, addition of



thousands of gallons of aviation fuel, Napalm and sodium chlorate, to-



gether with aerial bombing of the vessel, failed to produce sustained



burning.  Spilled oil may possibly be burned by using catalytic or com-



bustible agents or inducing "wicking" action between the oil and water.





The "wick" theory, assumes that capillary action is induced in the oil




slick and a portion of the oil is drawn up to air (oxygen)  interface to



promote burning.  Concurrently, the surface oil is partially insulated



from the cooling effect of the sea water underneath.  Wood, debris and



flotsam enmeshed with the spilled oil apparently also insulates this



layer from the colder water body and sustains burning.  Since freshly



spilled crude oil contains a relatively high proportion of volatile



components, its ignition is more feasible than for weathered crude where



the volatiles have already evaporated.  Besides potential materials such



as felting and asbestos-like agents, two commercial products are known



which promote the burning of oils on water.  One employs both a liquid



and powder.  The other is reported to consist of a specially-treated




fine silica which increases capillary action aiding in sustained and
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controlled burning.  Neither product, so far as is known, has been applied



in large-scale, and therefore factors of logistics, application and amount



of residue are unknown.





Controlling the burning oil mass, ensuing air pollution and disposal of




residue would appear to preclude the use of this course of action except



in those situations where the oil mass is sufficiently distant from the



•shore face and off shore facilities.  The possible loss of the vessel or



drill platform that is the source of the spill, is another factor which



must be recognized. Because of the potential value of burning, additional




and refined procedures should be further investigated.
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                                                           GPO 879-485

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