WORKSHOP ON
                 OCTOBER 2-4, 1973
                 DENVER, COLORADO
                 DISTRIBUTED BY
                NOVEMBER 1973

   Environmental Protection Agency
            Workshop on
  Sample Preparation Techniques for
     Organic Pollutant Analysis
          October 2-4, 1973

          Denver, Colorado


 Dr.  Theodore 0. Meiggs, NFIC-Denver

         Discussion Leaders

  Mr. James J. Lichtenberg, MDQARL

  Mr. Roger C. Tindle, NFIC-Denver

      Dr.  Ronald G. Webb, SEWL
          Distributed by

        Office of Enforcement
National Field Investigations Center
         Denver, Colorado
          November, 1973

                          TABLE OF CONTENTS






  V.  GENERAL COMMENTS  	     30

                             Workshop on
                  Sample Preparation Techniques for
                     Organic Pollutant Analysis
Dr. Clark Allen
Enforcement & Support Branch
Region VI
1600 Patterson Street
Suite 1100
Dallas, Texas  75201

Dr. William Andrade
S & A Division
Region I
Needham Heights, Mass.  02194

Mr. James Barren
Charlottesville Laboratory
Region III
1140 River Road
Charlottesville, Virginia  22901

Mr. H. Gregory Beierl
Pesticide Laboratory
S & A Division
Region VIII
Building 45
Denver Federal Center
Denver, Colorado  80225

Mr. Thomas Bellar
Methods Development & Quality
  Assurance Research Laboratory
Cincinnati, Ohio  45268

Dr. Frank J. Biros
Pesticide Effects Laboratory
Research Triangle Park, N.C. 27711

Dr. Joseph Blazevich
S & A Division
Region X
14515 SE 21st Place
Bellvue, Washington  98007

Mr. Harvey W. Boyle
National Field Investigations Center
Building 53, Box 25227
Denver Federal Center
Denver, Colorado  80225
Mr. Mike Carter
Southeast Water Laboratory
College Station Road
Athens, Georgia  30601

Mr. Richard Dobbs
Water Supply Research Laboratory
NERC - Cincinnati
4676 Columbia Parkway
Cincinnati, Ohio  45226

Mr. James W. Eichelberger
Analytical Quality Control Laboratory
1014 Broadway
Cincinnati, Ohio  45202

Dr. Richard Enrione
National Field Investigations Center
5555 Ridge Avenue
Cincinnati, Ohio  45268

Mr. Mike E. Garza, Jr.
Houston Facility
S & A Division
Region VI
6608 Hornwood
Houston, Texas  77036

Dr. Gary Glass
National Water Research Laboratory
6201 Congdon Boulevard
Duluth, Minnesota  55804

Dr. Donald F. Goerlitz
U. S. Geological Survey
Water Resources Division
345 Middlefield Road
Menlo Park, California  94025

Mr. William L. Griffis
Consolidated Laboratory Services
NERC - Corvallis
200 SW 35th Street
Corvallis, Oregon  97330

Mr. Michael Gruenfeld
Edison Water Quality Research
Edison, New Jersey  08817

                        PARTICIPANTS (Cont.)
Dr. Larry Harris
Analytical Quality Control
1014 Broadway
Cincinnati, Ohio  45202

Mr. Lloyd Kahn
S & A Division
Region II
Edison, New Jersey  08817

Dr. Robert Kleopfer
S & A Division
Region VII
25 Funston Road
Kansas City, Kansas 66115

Mr. Fred Kopfler
Water Supply Research Laboratory
NERC - Cincinnati
4676 Columbia Parkway
Cincinnati, Ohio  45268

Mr. Thomas Leiker
National Field Investigations Center
Building 53, Box 25227
Denver Federal Center
Denver, Colorado  80225

Mr. James Lichtenberg
Method Development and Quality
  Assurance Research Laboratory
Cincinnati, Ohio  45268

James E. Longbottom
Method Development and Quality
  Assurance Research Laboratory
Cincinnati, Ohio  45268

Mr. William Loy
Laboratory Services Branch
S & A Division
Region IV
Southeast Water Laboratory
College Station Road
Athens, Georgia  30601

Dr. Theodore 0. Meiggs
National Field Investigations Center
Building 53, Box 25227
Denver Federal Center
Denver, Colorado  80225
Mr. Jerry Muth
Laboratory Support Branch
S & A Division
Region IX
620 Central Avenue
Alameda, California  94501

Mr. William L. Reichel
Bureau of Sport Fisheries & Wildlife
Patuxent Wildlife Research Center
Chemistry - Pathology Building
Laurel, Maryland  20810

Dr. Peter Rogerson
National Marine Water Quality
South Ferry Road
Narragansett, Rhode Island  02822

Dr. Craig Shew
Robert S. Kerr Water Research Center
P. 0. Box 1198
Ada, Oklahoma  74820

Dr. David L. Stalling
Bureau of Sport Fisheries & Wildlife
Fish-Pesticide Research Laboratory
RD /'I
Columbia, Missouri  65201

Dr. Emilio Sturino
S & A Division
Region V
1819 West Pershing Road
Chicago, Illinois 60609

Mr. John Tilstra
S & A Division
Region VIII
Box 25345
Denver Federal Center
Denver, Colorado  80225

Mr. Roger C. Tindle
National Field Investigations Center
Building 53, Box 25227
Denver Federal Center
Denver, Colorado  80225

                        PARTICIPANTS (Cont.)
Dr. Oilman Veith
National Water Quality Laboratory
6201 Congdon Boulevard
Duluth, Minnesota  55804

Mr. Larry Wapensky
S & A Division
Region VIII
490 Orchard Street
Golden, Colorado  80401

Mr. Virgil L. Warren
National Field Investigations Center
Building 53, Box 25227
Denver Federal Center
Denver, Colorado  80225

Dr. James Watson
National Field Investigations Center
Building 53, Box 25227
Denver Federal Center
Denver, Colorado  80225

Dr. Ronald G. Webb
Southeast Water Laboratory
College Station Road
Athens, Georgia  30601

Mr. Robert E. White
Bureau of Sport Fisheries & Wildlife
Wildlife Research Center
Building 16
Denver Federal Center
Denver, Colorado  80225

Dr. A. J. Wilson
Gulf Breeze Laboratory
Sabine Island
Gulf Breeze, Florida  32561


     Throughout our Country, large quantities of industrial organic

chemicals are being discharged daily to our rivers and lakes.  Histor-

ically, the primary concern for these pollutants has been the oxygen

demand they exert upon the receiving waters.  However, it has become

increasingly apparent that many of these organic chemicals can produce

other adverse affects.  Many of these compounds are highly toxic to

aquatic life, some are carcinogenic, mutagenic, or teratogenic, while

others undergo bio-concentration within the food chain.  As a result,

the discharge of these materials into the aqueous environment can pose

a grave threat to the receiving water biota and in some cases even to

the ultimate consumer - man.

     Before much progress can be made to reduce this form of pollution

analytical techniques must be developed to identify and quantitate

individual chemical pollutants.  However, the complex mixtures of

organic compounds, and the low concentrations that are normally encoun-

tered, have made the analytical task formidable.  Recent advance in

analytical techniques and instrumentation have allowed some progress

to be made in this difficult task.  Consequently, a number of water

laboratories have begun to apply these new techniques to the analysis

of industrial-waste discharges and the receiving-water systems.

     The purpose and goal of this workshop was to bring together the

chemists who are responsible for organic-pollutant analysis, and to

serve as a forum to exchange the varied experiences and accomplishments

that have occurred in this rapidly developing field.  The emphasis of

the workshop was placed upon the problems of samnle collection,

extraction, and fractionation prior to detettion of the pollutants

of interest by the appropriate detection techniques.  Wherever pos-

sible, methods or procedures were stressed that were applicable to the

analysis for general classes of organic compounds as opposed to pro-

cedures for individual compound identifications.

     What follows is a summation of the techniques discussed at the

workshop.  Many of these are currently being used by water laboratories

to analyze industrial effluents, natural waters, bottom sediments, and

aquatic biota for industrial and agricultural organic-chemical pollu-

tants.  In addition, some discussion is provided regarding analytical

quality control in the organic laboratory as well as a summation of

miscellaneous, general comments that were expressed at the meeting.

     It is felt that the summary of this workshop will serve as a

guide to current practices in the analysis for organic-chemical pol-

lutants , and draw attention to those areas where more information

is needed.


     Sample collection and preservation is an area where considerable

research and development is needed.  There was general agreement among

the workshop particioants that there are, at present, no definitive

guides to sample collection and preservation for organic-pollutant

analysis.  In addition, less than ten percent of the laboratories repre-

sented indicated that they routinely participate in the actual collection

of samples for organic analysis.   This would Indicate that very few

chemists have direct input into the planning and conducting of sampling

programs.  In this respect, there was unanimous agreement that the analyst

should participate in the design of the sample collection process, par-

ticularly with respect to the preparation of sample containers, check on

purity of solvents and reagents,  etc.  Also, there was agreement that the

chemists should be allowed to train sampling crews to avoid potential

sources of sample contamination.

     In light of the expressed attitudes, it seems reasonable that some

group within EPA should be assigned the task of preparing a sampling

manual for use in training and guiding sampling crews who are to collect

samples for organic analysis.

     By far, the largest number of samples analyzed by the various

laboratories are grab-water samples.  Despite this fact, there seemed

to be little real knowledge of the effects of collection method, con-

tainer materials, handling procedures, etc. on the quality of the

resulting sample.  However, it should be emphasized that discussions

did not include the relatively well-developed area of pesticide residue

analysis since the planners of the workshop felt that pesticide residue

methodology is probably not sufficiently applicable to the problem of

sampling for the wide variety of industrial organic compounds that may

be encountered.

     There was considerable discussion on the choice of sample container

to be used in grab sampling.  Most attendees agreed that glass bottles

or jars were preferred, but one chemist suggested the possibility of

sample contamination due to leaching of materials from soft glass.  The

mechanism of contamination from this source is not known, but the use

of borosilicate glass (Pyrex, Kimax, etc.) seems to avoid the problem.

This phenomenon needs to be studied further.

     Most attendees felt that teflon-cap liners should be used to avoid

sample contamination and losses, but a limited amount of evidence sug-

gests that some solutes, notably PCBs, may be lost to, or through teflon

liners.  In these cases, aluminum-foil liners proved superior.  Again,

research is needed in this area.     )

     Some attendees pointed out that serious losses of solutes from

water samples may occur due to volatilization from the water surface.

This effect has been particularly noticed with petroleum samples.  A

recent paper by Mackay and Wolkoff [Env.  Sai. Technol. , 7, fill (1973)]

attempted to mathematically define the losses that occur due to vapori-

zation of various compounds, including Aroclor 1260.  The authors made.

some assumptions regarding vapor densities, etc., and produced some

rather interesting conclusions.  For example, if we assume that the

sanple bottle commonly used by EPA laboratories contains 850 ml of

liquid and 50 ml of air space, then at 4C about 20 percent of the

Aroclor 1260 from an Initially saturated solution will be found in

the air space.  Also, since this is the equilibrium situation, shaking

the sample should not redissolve the vaporized material.  At higher

temperatures, these losses would be even greater due to the greater

evaporation of water into the air space.  While some of the assump-

tions used for this estimate are probably not entirely true, the order

of magnitude is probably correct.  Thus, vaporization from a water

sample into the air space in a partially filled jar may represent a

"iajor source of error in the analysis of grab samples for PCBs, aro-

matics, alkanes, and other organic materials.  Obviously, the smaller

the air space above the sample, the smaller the losses that may occur

due to vaporization.  However, as pointed out by some of the Workshop

participants, if there is sufficient petroleum, or other organic material,

to form a microscopic layer over the surface of the water, then losses

due to capillarity (creeping of the organics out of the minute space

between the jar lip and the cap liner) may become significant when the

jar is nearly full.  Again, we have a problem that deserves consid-

erable attention.

     Contamination of grab samples was a major concern of most Workshop

participants.  Contamination can occur in many ways; one of the most

common results from inadequate pre-cleaning of sample containers.  To

minimize this, the chemists 'Should provide properly prepared (pre-

washed) containers to the sampling crews.

     Other sources of contamination are the caps used to seal sample

bottles (metal caps.must be freed of lacquer prior to use, while

plastic caps may contain plasticizers), sealing tape used to assure

that the caps remain tightly closed, glassware or other sampling gear

used to prepare the sample for transfer to the sample bottle, reagents

and solvents used for preservation, and possible other sources.  The

best answers to the contamination problem seem to be careful pre-

paration of the sample containers before use, training of field crews

so that they will avoid possible contamination sources, and careful

pre-screening (and if necessary, pre-cleaning) of reagents and solvents

for field use.  Among the most common contaminants are phthalate esters,

but many other types of compounds may be encountered.

     Integrated sampling comprises the various techniques whereby

samples are taken over an extended period of time, and in which the rate

of sampling is related in some manner to time or the rate of flow of the

sampled body.  The commonly practiced technique of manually compositing

grab samples over a period of time is an example of this type of sampling.

Compositing was not discussed to any extent during the workshop, however,

as usually practiced, solute losses due to vaporization probably repre-

sent a major problem when this method is used.

     The Workshop participants showed considerable interest in the use of

macroreticular resins for integrated sampling.  Four of the represented

laboratories, including three from EPA, had previously worked with

macroreticular resin columns.  Those that had used resins agreed that

this approach to sampling seems to hold a great deal of promise.

     In a recent example [R. Tindle, AQC Newlettsr, #19, October, 1973],

a mixed bed of Amberlite XAD-2 and XAD-7 (50:50 mixture) had been used

in a sampling column, which also contained polyurethane-foam plugs both

before and after the resin bed, to sample for several pesticide and

industrial-organic compounds ranging from hydrocarbons to phenols.

This system exhibited good, trapping efficiencies (>90 percent) for most

tested compounds, and upon elution gave overall recoveries generally

of >90 percent.

     Some Workshop attendees pointed out that recoveries may be flow-

rate dependent and some gel-filtration effects (exclusion of large

molecules) may be noted.

     The greatest potential for resin-column use seems to lie in the area

of long-term (24-96 hours) sampling for low levels of organics in lakes,

streams, etc.  Much work needs to be done to define the usefulness and

limitations of this method.  However, the potential usefulness certainly

justifies a concerted initial evaluation.

     Some of the characteristics of the resin-column samplers that need

to be defined are:

     (a)  quantitative aspects - "What compounds are quantitatively

          trapped and over what concentration range?"

     (b)  preparation of resins - "How can resins best be prepared

          for use?"

     (c)  column capacity - "What is the capacity of a particular

          size of column?  Are there interactions between solutes?"

     (d)  preservation of columns - "How can columns be preserved

          before extraction?"


      (e)  particulates on columns - "How should partlculates be

          handled?  What are the effects of partial plugging?"

      (f)  elution procedures - "What is best method of eluting

          columns?  Are separation based on pH or solubility


     There was some discussion of carbon adsorption.  Very few, if

any, of the represented laboratories now use this method, although

three Regional Offices appear to be considering use of this method

for monitoring purposes.

     There was almost no discussion of methods of collecting tissue

and sediment samples.  What discussion occurred centered around the

idea that EPA needs a written set of guidelines regarding the col-

lection of these types of samples.

     Discussions on the methods of preserving samples quickly revealed

an almost total lack of knowledge regarding the effects of various

alternative methods of preservation.  In general, most laboratories

simply place bottled-grab samples on ice for shipment as a means of

preservation.  However, it was clear that no one really knew whether

this approach is effective in preserving samples containing a variety

of industrial-organic compounds.               '

     Some attendees suggested the use of solvent in sample bottles as a

means of preservation.  There was, however, little agreement as to which

solvent should be used.  For low-boiling pollutants, the use of hexa-

decane as a keeper solvent seems to have some utility.  Various solvents,

including methylene chloride, Freon TF, hexane, isooctane, etc., were

suggested for use as keepers for higher-boiling pollutants.  Some form

of keeper in the bottle would seem desirable to reduce possible loss

by volatilization as discussed previously.

     Petroleum-containing samples are preserved by the addition of

sulfuric acid [M. Gruenfeld, Env. Soi.  Teohnol. 3 7, 636 (1973)], while

formalin was suggested for PCB-containing samples [T. A. Bellar and

J. J. Lichtenberg, "Some Factors Affecting the Recovery of PCB's From

Water and Bottom Samples," CIC-CCIW Symposium on Water Quality Parameters,

Burlington, Ontario, November, 1973].  Copper sulfate and phosphoric acid

are often used to preserve samples for phenols analysis.

     Tissue- and bottom-sediment samples are preserved by freezing by

almost all represented labs.  A recent paper [Butler, Pest. Monitor1. J.t

6, 238 (1963)] reported the use of a mixture of 90 percent anhydrous

sodium sulfate and 10 percent Quso G30 (micro-fine precipitated silica)

to preserve field-blended-tissue samples.  This method allowed the

storage of desiccated-tissue samples for at least 14 days without loss

or degradation of pesticide residues.

     This area of preservation of samples is another highly important

area requiring extensive research.  Hopefully, the various EPA research

groups will expend the needed effort to define suitable preservation

techniques for both water and other samples.

                     II.  EXTRACTION PROCEDURES

     Extraction procedures cover a wide variety of techniques whereby

the organic pollutant(s) of interest are transferred from the inorganic

or biological matrix (i.e., water, sediment, or tissue) and usually

concentrated prior to chemical characterization.  During the Workshop,

extraction techniques were discussed for separating organic pollutants

from water and wastev/ater samples, tissue, bottom sediment, and sludge


     The simplest situation occurs when no extraction is required.  In

this case, the chemist may apply such techniques as direct aqueous-

injection gas chromatography, head-space analysis, trapping of volatile

components by either gas purging or cold trapping and finally, steam


     The technique of direct aqueous-injection gas chromatography (GC)

was familiar to most workshop participants.  Those who had applied it had

found it most useful for the analysis of volatile organics in effluents

where the detection limit of approximately 1 mg/1 is adequate.  The use

of pre-columns to prevent salts and other non-volatiles from damaging

the GC column was recommended by several participants.  Quartz inserts

or lengths of column tubing at the head of the GC column, either empty

or packed with quartz wool, can be employed for this purpose.  These

inserts can be changed or cleaned with a minimum of effort.  Direct

aqueous injection is currently being recommended by the EPA Methods

Development and Quality Assurance Research Laboratory (MDQARL) in the

analysis for chlorinated and aliphatic solvents.  For these analyses,


the halogen specific micro-coulometric or the non-specific flame

ionization detectors are employed.  Direct aqueous injection is recom-

mended by ASTM for the analysis of phenols in their "Standard Method

of Test for Phenols in Water by Gas Liquid Chromatography" (D2580) and

for the analysis of volatile organic matter in water in their Method

(D2908).  Additional methods of direct aqueous injection for organic

acids, nitrites, and aliphatic hydrocarbons are presently being pre-

pared by ASTM and others [D. Brown, AQC Newsletter", (19), 5 (1973)].

     Head-space analysis can also be applied for the determination of

volatile-organic materials although few of the Workshop participants

had actually employed it in practice.  The use of infrared spectro-

scopy has been reported for the quantitative identification of head-

space gases in oil samples.

     Other techniques for the analysis of volatile organics use gas

purging to remove volatiles from the samples.  Tom Bellar reported the

use of nitrogen gas to purge volatile-organic components from water

samples.  The evolved organics are then collected on an adsorbent

column (Chromosorb 103).  The collection column is then inserted into

the injection port of a gas chromatograph and the trapped components

analyzed under temperature-program conditions.  The technique has been

applied to a variety of chlorinated and non-chlorinated aromatic ami

aliphatic solvents.  Under ambient conditions, the recovery of relatively

insoluble organic compounds -has been found more efficient than the

recovery of highly water-soluble compounds.  Instead of collecting

the purged volatile-organics on a column, the materials may be col-

lected in a cold trap.  This technique has been used by several of the


laboratories in attendance and is a relatively common technique in the

analysis of atmospheric samples.

     Steam distillation can be used to reduce the sample volume and to

concentrate organic components that are volatile under such conditions.

Samples thus concentrated can be analyzed by direct-aqueous injection

or by solvent extraction prior to GC or other types of detection.

However, possible hydrolysis of sample components must be carefully

considered when ever this technique is employed.

     Liquid-liquid extraction is by far the most common type of extrac-

tion technique in dealing with water and wastewater samples.  The Work-

shop participants were queried as to the most common types of solvents

used for this purpose and it was found that the solvents most commonly

used were methylene chloride or chloroform, follox^ed by ethyl ether,

hexane, methylene chloride-hexane, and finally by ethyl ether-hexane

mixture.  Other solvents that were mentioned but not widely used, were

carbon tetrachloride for oils, freon for oils, benzene-hexane, hexane-

acetone and hexadecane.  A consensus of the Workshop participants was

that, whenever possible, non-flammable solvents such as methylene

chloride or freon should be used.  The potential explosive hazard of

diethyl ether and other flammable solvents should not preclude there

use when needed.  However, the chemist must be aware of the hazard and

take measures to minimize the possibility of accident.  Obviously, the

solvent of choice will depend upon the types of pollutants to be analyzed

or to be characterized.

     In the case where a wide variety of organic types are to be deter-

mined, liquid-liquid extraction can be used as a fractionation tool as

well as a separation technique.  A procedure for the separation of

neutrals, acids, and bases was described by William Loy of the Southeast

Water Laboratory.  In this procedure, conditions for the initial extrac-

tion of the sample are determined by the pH of the sample as received.

The sample is shaken to provide homogeneity and is divided into two equal

portions for replicate analysis.  If the pH of the sample is between

5 and 14, the sample is initially extracted with hexane to recover the

"neutral organics" which are then analyzed by gas chromatography.  After

the neutrals have been removed, the sample is then acidified to pH 2 and

extracted with methylene chloride.  The methylene chloride extract is

then concentrated and divided equally.  One aliquot is analyzed directly

by gas chromatography, the second is esterified, using diazomethane prior

to analysis by gas chromatography.  If the original sample has a pH less

than 5, the sample is acidified to pH 2 and extracted only with methylene

chloride.  The methylene chloride extract is then divided and analyzed

or esterified as above.  In some cases, organic bases may be recovered

by adjusting the pH of the sample to greater than 10 and extracting with

methylene chloride or other appropriate solvent.  Extraction of the

samples may be carried out using separately funnels or a magnetic stir-

ring device.  The magentic stirring approach is satisfactory when

extracting with a lighter-than-water solvent; it is not very efficient

when using a solvent that is heavier than water.

     A good discussion of liquid-liquid extraction can be found in the

ASTM Manual, Part 23, Method D-2778 "Solvent Extraction of Organic

Matter from Water".  This method describes a general approach that will


separate a wide variety of organic components and allows the analyst

to select from a variety of solvents as required to meet his needs.

     Workshop participants reported that recoveries from industrial

waste samples were variable and often poor.  Salting out was suggested

as a method for improving recovery.  The use of sub-ultrasonic (polytron)

or ultrasonic treatment to break up the suspended solids in a sample was

also suggested as a means of improving the extraction efficiency.  It

should be noted that heavier-than-x^ater solvents can cause problems

during phase separation when the samples contain fibers for other solid

materials that tend to settle to the bottom.

     A procedure for breaking emulsions by pouring the sample through

glass wool was presented to the Workshop by William Loy.  The procedure

calls for passing the organic layer through a column of 2-3 inches of

Pyrex glass wool (prerinsed with methylene chloride) and collecting it

in a beaker.  If necessary, the solvent is forced through the glass wool

by applying mild air pressure.  If a layer of water is present after

passing through the glass wool once, it is passed through a second

column for final drying.  Some unanswered questions regarding this tech-

nique are the following: Are organics that may be occluded in emulsi-

fied material lost as this material is removed by the glass wool?  Does

the glass wool do an adequate job of removing the water from the solvent

extract?  Mr.  Loy is working to answer these and other questions.

     Sulfur is often extracted from environmental samples into the

organic layer.  In order to avoid sulfur interference, the sulfur may be

removed with mercury or copper powder (Bull. Fnviron. Cent, and Toxic.,

6, 9(1971).


     An alternate approach for recovery of organic pollutants from

vrater and wastewater is adsorption on organic resins or activated

carbon followed by solvent extraction of the resin or carbon to desorb

the organic pollutants of interest.  A number of Workshop participants

have used the Rohm and Haas XAD resins for the recovery of a variety

of organic compounds.  Though this relatively new technique is not yet

fully developed, it has shown considerable promise for some applications.

A preliminary literature review of work with this technique has been

prepared by Roger Tindle, NFIC-Denver.

     Investigations of procedures for extracting organic materials from

the XAD resins are in progress.  A number of solvents have already been

applied singly, in series, or as mixtures.  Examples are acetone, methanol,

or ethanol used singly or acetone followed by methylene chloride followed

by acetone again in series, or a single elution using a mixture of acetone

in chloroform.  Some degree of class separation based upon pH can be

achieved using the resins, however, more work needs to be done in this

area.  Some of the problems surrounding the use of the resins are the

same as those encountered for the carbon adsorption technique.  These

include, variable particle size, background interference, unknown ef-

ficiency, plugging by suspended matter, etc.; however, there are a

number of decided advantages of the resin over the carbon such as lack

of active sites which minimize chemical changes on the resin surface.

     Polyurethane foams have also been employed with the extraction of

certain organics from water.  In general, the foams have been found to

work well for the extraction of non-polar compounds, e.g., PCB's; how-

ever, they are not very effective for the extraction of more polar

compounds.  A combination of the XAD resins and the polyurethane foams

have been applied by NFIC-Denver with good success.

     Historically, carbon adsorption has been widely used for the

separation of organic components from water.  However, due to its non-

quantitative nature, expense of sampling, etc. it has fallen into disuse.

The normal procedure for removing organics from carbon has been air

drying of the carbon, followed by extraction first with chloroform fol-

lowed by extraction with alcohol.  Dr. Clark Allen reported at the Work-

shop that a considerable increase in extraction efficiency can be obtained

if the carbon is dried by freeze drying instead of air drying.  Apparently,

much greater removal of water is obtained this way and more thorough con-

tact is achieved between the carbon and the extraction solvent.  Although

the Methods Development and Quality Assurance Research Laboratory has now

terminated surveillance operations using the carbon adsorption technique,

there is still some interest among the Regions in the use of this tech-

nique for separating and identifying organic compounds from water.

     A number of the EPA laboratories have found the need, on occasion,

to analyze tissue samples for organic chemical pollutants.  It is anti-

cipated that the need for this type of activity will be increased since,

especially from an enforcement standpoint, there is a legal necessity

to demonstrate the effects of pollutants on the environment.  Measuring

the uptake of chemical pollutants by aquatic life is one way to demon-

strate this.

     The extraction of tissue samples for organic pollutants is con-

siderably different from the extraction of water and wastewater samples.

Most work in this area has centered around the analysis for pesti-

cides and/or petroleum products.  Certain types of organic pollutants,

such as oils, can be extracted by adding an organic solvent while the

tissue sample is being masserated in a blender.  This technique has

been found to be especially useful when using sub-ultrasonic mixers,

such as the Polytron (Brinkman instruments) and the Tissu-Mizer (Tek-

Mar Company).  Several Workshop participants have investigated this

technique and feel that it shows promise for certain applications

[J. Agv.  Food Chem.  20. 48, (1972)].

     Blenders can also be used to prepare samples for column extraction.

For this technique,  the sample is ground in the presence of dry ice

and sodium sulfate [J.  Agr. Food Chem., 18, 948, (1970)].  Following

grinding, the dry ice is allowed to sublime from the sample leaving a

fine powdery material.   Once the tissue has been dried in this fashion,

it can be packed in a chroraatographic column and extracted by elution

with a solvent such as acetone, methanol, or acetone-haxane (1:1) [(Bull.

Envir.  Contam.  Toxi., 7_, 1151, (1972) and Southeast Water Laboratory,

EPA, Athens, Georgia, Method No. SP-8/71].  An alternate technique is

freeze drying the tissue samples.  Dr. A. Wilson of EPA's Gulf Breeze

Laboratory has used this method for preparation of phytoplankton samples.

     Tissue samples  can also be extracted by use of a soxhlet extrac-

tor.  This seems to be about as commonly applied as the column extrac-

tion technique.   Some of the solvents employed for soxhlet extraction are

petroleum ether, methylene chloride, acetone-hexane, methylene chloride-

hexane, acetonitrile, ethyl acetate, and acetone-benzene.  The use of


phosphoric acid acetone (1:2) has been used for the extraction of


     Bottom sediment and sludge samples can be extracted by techniques

that are similar to those applied to tissue samples, namely, column

extraction, soxhlet extraction and blender extraction.  Sample pre-

treatment, however, varies depending upon whether the extraction is to

be done under wet or "dry" conditions.  Workshop participants discussed

five different approaches to pre-treatment, namely: 1) air drying at

ambient conditions, followed by grinding with a mortar and pestle and

addition of 10 percent water followed by soxhlet extraction; 2) partial

air drying (30-40 percent moisture) at ambient conditions and blending

with sodium sulfate followed by column extraction; 3) decanting excess

water and blending the wet sample with sodium sulfate followed by column

extraction; 4) decanting excess water and extracting the wet sample by

shaking with solvent using no dessicant; and 5) blending of the wet sample

directly with solvent.

     Once a sample has been "dried" it may then be extracted either by

column elution or soxhlet extraction.  Solvents normally employed are

acetone-hexane, acetonitrile-hexane, methylene chloride, acetonitrile,

ethyl acetate, and acetone-benzene.  Soxhlet extraction of sediment

samples has been described many times ("The Identification and Measure-

ment of Chlorinated Hydrocarbon Pesticides and Surface Waters", U. S.

Department of the Interior, 1014 Broadway, Cincinnati, Ohio, Publication

WP-22, 1966.)  This technique is found to give good recovery of com-

pounds that are stable and do not volatilize under the conditions of


     Organic pollutants can be extracted from sediments by mixing directly

with the solvent of choice.  Although no laboratories are presently using

Waring Blenders for this type of extraction, both mechanical shaking

("Methods for the Analysis of Organic Substances in Water", Book 5,

Chapter 83, Techniques of Water Resources Investigations, the U.S.G.S.,

1972.) and sub-ultrasonic mixing are being employed with varying degrees

of success.  The latter technique looks especially promising; however,

further work is required to access its full utility.

     In general, it was concluded at the Workshop that air drying of

the sample is not a good practice when a broad spectrum of organic com-

pounds is to be determined.  Significant amounts of very volatile organic

compounds can be lost if air drying is employed, e.g., BHC has been

found to volitalize readily under these conditions.  On the other hand,

extraction of some compounds from environmentally contaminated sediments

has been significantly more efficient when carried out on an air-dried

sample.  Thomas Bellar of the MDQARL reported that both PCBs and dieldrin

are more efficiently extracted from natural samples that have been dried

in this fashion.

     It was recognized by the Workshop participants that a great deal

of work needs to be done to determine which extraction procedure, if

any, is superior.  However, an even greater area of concern is the wide

variations that occur during sample collection.  It was the general con-

cession that for tissues and sediments, the sampling variations and

biological variations are much larger than analytical variations and

often account for the wide discrepancies in replicate analysis.


     Samples that are too complex to be separated under normal OC con-

ditions are usually subjected to some form of fractionation during, or

after, extraction.  Six workshop attendees reported that they frequently

use some form of acid-base separation for water samples, particularly

industrial effluents.  They preferred to use a simple two- or three-step

scheme although they were aware of Braus, Middleton and Walton's more

complex scheme that separates neutral compounds, strong acids, phenols,

bases and amphoteric compounds [Anal. Ch&n. 23, 1160 (1951)].  Typically,

they extract the sample, as received, to isolate neutral compounds.  Then

they acidify to about pH 2 and extract to isolate acids and phenols.

Phosphoric, sulfuric, or hydrochloric acids are used for this step.  The

aqueous layer is then adjusted to pH greater than 8 with ammonia or

dilute sodium hydroxide to form free bases and the sample is extracted

a third time.

     Some acids and phenols from the acid fraction can be analyzed

without further treatment.  Acetic through hexanoic acids can be

chromatographed directly on Chromosorb 101 in an all-glass system.

Carbowax 20M and FFAP have been used to analyze simple phenols, cresols

and similar materials in paper-mill effluents.  The longer acids and

more complex phenols are usually converted to methyl esters and ethers.

The most commonly used methylating agent is diazomethane.  Phenols

react more completely with this reagent when a little boron trifluoride

in methanol is added as a catalyst.  The extract must not contain any

chloroform because it reacts with diazomethane to form di- and

trichlorinated alkanes up to seven carbons long that complicate the GC

analysis.  Methylene chloride does not cause this problem.  A discus-

sion of methylation procedures, including several on-column reagents

is given in the report from SERL on "Current Practice in GC-MS Analysis

of Organics in Water" (EPA-R2-73-277).

     Other groups feel that trimethylsilyl (IMS) derivatives give more

definitive mass spectra than methyl derivatives.  They recommend BSTFA

(N,0-bis-trimethylsilyl trifluoroacetamide) as the reagent of choice.

One trade name is Regisil.  Another derivatization mentioned, but

apparently rarely used, is to form pentafluorobenzyl ethers, thioethers

or esters from phenols, mercaptans and acids.  [Kawahara, Anal. Chem.

40, 1009 and 2073 (1968)].

     In contrast to neutral compounds and acids, very few bases have

been identified in the environment.  The Workshop participants agreed

that judging from manufacturing data, industrial usage and the size of

the basic fractions in past CCE studies, these compounds must be in the

environment but we are not seeing them.  This is a major weakness in

our present analytical techniques.

     Among the bases that have been found are picolines (methyl

pyridine isomers) in river water, dibutyl amine from a latex-additives

plant and quinoline and di- and trimethyl pyridines from a wood-pre-

serving plant.  Several dichloroaniline isomers and other nitrogen

containing compounds in industrial effluents were identified by

NFIC-Denver after conversion to TMS derivatives.  Several aromatic

amines from biological sources were reported as analyzed in good

yield by conversion to the amides with pentafluoropropionic anhydride

and analysis by EC-GC.

     Some methods-development work on amines has been done.  Many

simple amines can be gas chromatographed by direct aqueous injection

on Tenax columns.  One report was that Chromosorb 101 can also be used

for this purpose although the 103 material is recommended.  Another

worker found that methyl and dimethyl amines can be sampled by the

headspace-gas technique and then analyzed by GC on OV-101.  Low-

molecular weight amines were also reported as separated from other

impurities by adsorption on weak acid cation exchange resins.

     A wide variety of post-extraction chromatographic cleanup techni-

ques were discussed.  Oils are frequently chromatographed on Florisil

or silica gel in a manner similar to pesticides.  Some use a column

containing silica gel on top of alumina.  This column, deactivated with

4 percent water, was reported to separate oils from sewage when eluted

with carbon tetrachloride.  Another observation was that a useful

second dimension of proof in oil fingerprinting by GC was to separate

the oil into aliphatic, aromatic and oxygenated fractions by eluting

from silica gel with isooctane, benzene and 1:1 chloroform-methanol by

the method of Rosen and Middleton [Anal. Chem., 27, 790 (1955)].  Phenols

can be isolated from carbon chloroform extracts (CCE's) by extracting

the chloroform with base, extracting the acidified-aqueous layer with

ether, and then chromatography on Florisil with ether as the eluting



     Thin-layer chromatography (TLC) would seem to be a very powerful

technique in view of its low cost, and the visual impact it can have

in a courtroom.  In practice however, it is used little in pollution

analysis because of its lack of discrimination and sensitivity.  Poly-

nuclear aromatic hydrocarbons (i.e., benzopyrene) have been separated

and detected; phenols from CCE's have been detected down to one microgram

per spot, and some amines can be analyzed by TLC.  Identification of

sources of oil spills by TLC has been extensively studied, partially

through EPA grants to Esso and Phillips Petroleum, but there are still

problems with the method.  Two areas for future research on TLC were

suggested  reversed phase TLC for polar compounds, and detection of

specific classes of compounds in industrial effluents by specific spray

reagents.  Nobody seemed to be planning any immediate activity in these


     Another method mentioned for detecting specific compound groups

was the use of GC subtraction columns.  These are short lengths of

tubing containing a chemical that removes specific compounds.  They

are placed between the GC injector and the column.  Boric acid sub-

tracts alcohols, o-dianisidine subtracts aldehydes and ketones, phos-

phoric acid subtracts epoxides [Beroza, JAOAC, 54, 251 (1971); see

also Chem.  Abst., 74, 134709z (1971)].  No one reported first-hand

experience with this procedure.

     Liquid chromatography as a cleanup method has not been extensively

applied.  It was not an improvement over column techniques for cleanup

of oils for fluorescence analysis.  There was one report of permaphase


columns bleeding enough to show up later in GC-MS analysis of the

individual fractions.

     Of at least ten LC's in EPA labs, four have been bought x^ithin

the last year and are too new to be properly evaluated.  It was generally

concluded that a detector breakthrough will have to be made before LC

finds extensive application in pollution analysis.

     Probably the most promising cleanup technique is some form of

automated gel-permeation chromatography.  Gel permeation is not uni-

versally applicable, but it is useful for eliminating interference from

compounds of molecular weights greater than about 700.  One example

cited was in analysis of an oily-fish extract containing PCB's toxaphene

and chlordane.  Gel permeation allowed isolation of the combined pesti-

cide mixture.  Further cleanup on silica gel and alumina was required

before the separate materials could be analyzed.  NFIC-Denver plans to

evaluate the application of gel permeation to industrial effluents.



     There are two major categories to be considered when discussing

analytical quality control in the organic laboratory.  The first is the

qualitative aspects of the analysis, that is, the degree of certainty

that the unknown constituent has been correctly identified.  The second

category involves the quantitative aspects of the analysis, that is,

the acceptability of the precision and the accuracy of the results

obtained.  A discussion of this subject is presented in the "Handbook

for Analytical Quality Control in Water and Wastewater Laboratories",

Analytical Quality Control Laboratory, Cincinnati, Ohio, 1972.

     In regard to qualitative control, it was recognized by the Workshop

participants that the first step requires checking and eliminating inter-

fering background components from all reagents, solvents, glassware and

other equipment employed in the analysis.  Once the analyst has assured

himself that interferences are not present, he must then recognize that

selective extraction of particular compounds may occur depending upon the

pH of the sample, the solvents used, and other factors.  Consequently,

various separation or "cleanup operations" may be required to provide

additional support for the qualitative identification of specific con-

pounds.  Final qualitative identifications can be achieved by a variety

of techniques.  The current best methods are GC-MS, infrared spectro-

scopy, and multiple column gas chrorato^raphy.  The latter technique

is enhanced when a sendspecific detector sucli as the T7PD or Coulsen

micro-coulometric can be used.  Obviously in all cases of instrumental

analysis, close control nust be maintained of the instrumental parameters,

     In regard to the quantitative aspects of quality control, both

replicate and spiked sample analyses must be performed periodically

to assure the precision and accuracy of the test; however, due to the

complexition of organic analysis, time constraints are often the con-

trolling factor in limiting the number of replicates or spiked sample

analyses that can be performed.  As a guide to the types of techniques

that can be employed, several of the Workshop participants described

the quality control procedures that they presently employ in their

laboratories.  These are summarized below.

     William Loy, Chemical Services Branch, Southeast Water Laboratory

 At this laboratory all water samples are analyzed in duplicate.  When

samples are to be analyzed for a broad spectrum of industrial chemicals,

selected samples are spiked with a mixture of six known organic compounds.

These known compounds cover the range of volatile, basic, acidic, and

neutral compounds at a concentration of 100 yg/1 in acetone.  Problems

with recovery have been encountered only when large amounts of particu-

lates are present in the sample.

     James Lichtenberg, Methods Development Quality Assurance Research

Laboratory  In this laboratory one set of duplicate samples is run with

each series that is analyzed, usually one duplicate for every nine samples,

Simultaneously, one sample is dosed with a mixture of known compounds of

the same class as those to be determined and analyzed along with the

other samples.

     Robert White, Wildlife Research Laboratory  In this laboratory,

which deals primarily with tissue analysis, every ninth sample is

repeated though not at the same time as the first analysis.  The second

analysis is randomly performed either by the same or different analyst.

When running the repeat analysis, the chemist goes back to his primary

reference standard-stock solution to insure that the standard used in

the initial analysis was accurate.  The results are independently

reviewed by a second analyst before being reported.  Control charts are

maintained for several concentration levels using a computer program

devised by this laboratory.  From time to time, collaborative studies

are conducted with other laboratories.

     Dr. David Stalling, Fish Pesticide Research Laboratory  This

laboratory uses many of the techniques described above; however, they

also use alternate test procedures to check upon the reliability of

the reported results.  Primarily, they use carbon-14 tagged materials

to check each step in the analytical procedures.  With this system, each

analyst is required to withdraw 10 percent of the sample extract obtained

from each step of the analysis, e.g., extraction, concentration, elated

fractions from cleanup steps, etc.  These aliquots are then analyzed by

liquid scintillation and the recovery in each step is determined.  These

results are then compared with the results obtained by routinely applied

techniques, such as gas chromatography.  So far, the technique has been

applied primarily for quality control during tissue analysis and for

such analysis, no GC interference is noted at the dosing levels required.

However, in the analysis of the low levels of organics found in natural

waters, such an interference may be a problem.

     This approach to quality control appears to be quite intriguing,

especially because once it is set up it is very easy to operate.  Liquid

scintillation counting requires a minimal amount of time and effort.

Consequently, much more quality control information can be gathered

than by conventional techniques.  One of the main problems with this

technique is the cost of the carbon-14 labeled compounds and the

accessibility of a liquid scintillation counter.  It is not incon-

ceivable, however, that one central location could provide this service

to many of the EPA laboratories.

     A variety of other techniques were discussed by the Workshop

participants which should help in the quality control program.  For

example, several of the participants use internal standards for both

qualitative and quantitive purposes.  In one laboratory, a known

reference standard equivalent to the tentatively identified unknown

is added to the sample and the gas chromatographic response compared

to that produced by the reference standard alone.  In another case,

the response factor of a selected internal standard (not the same as

the compound identified) relative to the compound to be identified is

determined.  This factor is then used for future calculations of the

quantitative results.

     In the quantitation of gas chromatographic peaks, it was generally

observed by the Workshop participants that peak area is more accurate

for later eluting peaks.  Peak height, however, is best for very early

eluting peaks.  It should be noted that the volume of an injection

affects the peak width and therefore the injected volume should be


close to the same for both the sample and reference standard.  In all

cases, the detector must be operated within its linear range.

     Sample injection technique is critical during gas chromatographic

analysis.  A number of laboratories use the solvent-flush technique

in which a small volume of pure solvent is pulled up into the barrel

of the syringe before the sample.  Upon injection, this pure solvent

flushes all the sample from the needle and complete transfer of the

sample is assured.  When they are available, automatic sample injectors

have been found to give very reproducible results and their use should

be encouraged whenever possible.  In all cases, the analyst is encouraged

to use the technique best suited to him.

                        V.  GENERAL COMMENTS

     A variety of items not covered in the preceding chapters were

brought up during the general discussion period of the Workshop.  Some

of these items are summarized below in varying detail.

     A number of Workshop participants were greatly interested in the

proposed list of Toxic Substances [Federal Register, Vol. 38, No. 173,

Sept. 7, 1973)].  Much of this interest x?as in the form of concern for

the brevity of the proposed list and questions as to why the materials

listed were the ones chosen.  As no answers to these questions were

forthcoming, the discussion shifted to analytical procedures for

measuring these toxic substances.

     Most participants agreed that suitable procedures were presently

available for measuring polychlorinated biphenyls and the chlorinated

hydrocarbon pesticides, aldrin, dieldrin, toxaphene, etc.  However,

little information was available regarding the analysis for benzidine

(4,4-diarainodiphenyl) and its salts.

     The MDQARL is presently working on methods for benzidine.  A color-

metric method is currently recommended [M. A. El-Dib, JAOAC, 54, (6),

1383 (1971)]; however, it is not specific for benzidine.  Work is pre-

sently underway on a thin-layer modification of this method and a GC

procedure, both of which would be more specific.  It should be noted

that the free base form of benzidine can be chromatographed on SE-30

columns and also on Tenax columns although some partial adsorption

is observed with the latter.


     Benzidine can be removed, from water by carbon adsorption of the

HC1 salt; however, the salt apparently cannot be recovered from the

carbon by chloroform or alcohol extraction.  A search was made of the

CCE extracts on file from the Surveillance Network of the FWPCA, and

no benzidine was found.

     The MDQARL has found that the free base can be quantitatively

extracted from water at pll 10 with chloroform.  Uater samples of

benzidine do not appear to be stable.  Benzidine was found to react

rapidly with Cincinnati tap water (presumably the chlorine) to form a

precipitate.  Even standards, made up with distilled water turned cloudy

within one week.

     An alternate approach was suggested by Dr. David L. Stalling.

Trifluoroacetic anhydride is a good derivatizing agent for amines, and

Dr. Stalling suggests that this reagent may form derivatives with

benzidine that will be easily chromatographed.  This, of course, will

need to be checked.  With no other comments concerning the Toxic Sub-

stance List, the discussion turned to the Ocean Dumping Criteria.

     These Criteria were recently promulgated by EPA.  The Proposed

Criteria appeared in the Federal Register, Vol. 38, No. 94, May 16, 1973

and the Final Criteria were published in the October 15, 1973 Federal

Register,  Vol. 38, No. 198, Part II.  The Criteria lists a number of

potential organic pollutants that require "special consideration" prior

to issuance of a dumping permit.  Consequently, many Workshop partici-

pants felt they may be required at sometime in the future, to analyze

wastes for these materials and, as a result, they were quite interested

in any information as to how to perform such tests.


     First on the list were organosilicon compounds.  No one at the

Workshop was aware of any pollution problems associated with organo-

silicon compounds and consequently it was unclear just what compounds

would be of most concern.

     In regard to other organometallic pollutants, it was evident that

little work had been done in this area.  The National Water Quality

Laboratory at Duluth has apparently looked very briefly at organocadmium

and organocopper compounds.  The Edison Laboratory has had some exper-

ience with organolead materials in oil wastes.

     The Ocean Dumping Criteria also listed aliphatic solvents as waste

components that require "special consideration."  A variety of methods

appear to be available for this analysis, namely, direct aqueous injec-

tion, head space analysis, GC analysis of volatile components trapped

on Chromasorb 101 or other material following purge by inert gas, and

finally, extraction with a high-boiling solvent such as hexadecane  fol-

lowed by GC analysis.  The method of choice would depend upon the needs

of the particular laboratory although all the cited procedures seem


     The Workshop participants felt that they could test for phenols

either by the steam distillation - 4-aminoantipyrine - procedure in

Standard Methods or by the gas chromatographic procedure in the ASTM

Manual, Part 23.

     Plastics, plastic intermediates and byproducts seemed to be an

unknown quantity to the Workshop participants.  Undoubtedly, many

compounds in this category could be identified by gas chromatography/

mass spectrometry following work up procedures previously discussed,


i.e., phthalate plasticisers [D. L. Stalling, et. al.t Environmental

Health Prospeatives, 159 (1973)].  However, before additional tests

can be considered, we will need more information concerning just what

compounds in this category actually represent a pollution hazard.

     Analytical procedures for amines were discussed previously.

     Polynuclear aromatic hydrocarbons can be identified by a variety

of procedures.  Several participants felt that the easiest procedures

to apply were colormetric, as recommended by the World Health Organization,

and thin-layer chromatography [E. Sawicki, et. al.3 Health Lab. Sci. 7

(1)68 (1970)] even though the specificity of these procedures is unknown.

In addition, many of the aromatic hydrocarbons can be separated and

identified by gas chromatography.  Participants recommended columns

of OV-1, Dexil, and Apiezon L.  Undoubtedly, others are available.

Liquid chromatography has also been used and appears to hold considerable

promise [N. F. Ives and L. Giuffrida, JAOAC, 55_, (4), 757. (1972)].  In

tissue samples, polynuclear aromatic hydrocarbons can be identified by

fluorescence following a rigorous clean-up procedure [J. W. Howard,

et. al.3 JAOAC, J51, 122 (1968); AOAC Methods3 llth Ed. Si. 001, pg 361

(1971].  From the above discussion, it was evident that a number of

potentially suitable procedures are available, however, at present, none

of the participants had applied any of these tests to industrial waste-

waters, sludges, or dredge spoil.

     Little work has been done on detergents other than extraction of

ABS or LAS by the MBAS tests described in Standard Methods.  The MDQARL

has used TLC procedures to identify polyoxyethylene-type detergents in

CCE extracts from carbon filters [ASTM Special Tech. Pub. No. 448, p 78


 (1969)].  No other analytical procedures were mentioned by the Workshop

participants.  This may be a potential-problem area since there are

published references to the extreme toxicity of some surfactants to

aquatic life [n. J. Wildish, and W. G. Carson, Fisheries Research

Board of Canada Report, Series No. 1212, October (1972); D. J. Wildish,

Water Research, 6_, 759 (1972)].

     A brief discussion took place at the Workshop regarding the limiting-

permissible concentrations of pollutants listed in the Criteria.  The

final revision of the Criteria uses the bioassay tests as the basis for

limiting the concentrations of pollutants.  It was generally agreed by

the Workshop participants that neither bioassay nor concentration limits

would be satisfactory by themselves.  Hopefully, sometime in the future,

limitations will be based upon some suitable combination of pollutant

concentrations and bioassay information.

     In regard to bioassay and toxicity studies, it was pointed out that

a number of computer-based information systems are presently available

that store toxicological information.  Should any of the EPA offices

need such information, NFIC-Denver is tied into a number of these library

systems, notably, TOXICON and others, and will be glad to assist in

gathering the necessary data.

     At the conclusion of the Workshop, it was brought out that a real

need exists for some simplified, screening methods of analysis.  Quite

obviously, the complexities and time requirements of detailed organic

analysis of industrial wastes preclude the ability to monitor a large

number of waste streams.  Hopefully, procedures can and will be devised

whereby a large number of samples can be quickly screened and only those

that test above a certain level will need to be set aside for detailed

analysis.  Certainly that is a worthwhile goal and we would encourage

any thoughts on the matter.