ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
WORKSHOP ON
SAMPLE PREPARATION TECHNIQUES
FOR
ORGANIC POLLUTANT ANALYSIS
OCTOBER 2-4, 1913
DENVER, COLORADO
DISTRIBUT__
NATIONAL FIELD INVESTIGATIONS CENTER-DENVER
DENVER, COLORADO
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Environmental Protection Agency
Workshop on
Sample Preparation Techniques for
Organic Pollutant Analysis
October 2-4, 1973
Denver, Colorado
Chairman
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
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TABLE OP CONTENTS
Page
PARTICIPANTS . . . . . , . . . jj
INTRODUCTION . . . . . . . . . . . . . . . . . . . 1
I. SAMPLE COLLECTION AND PRESERVATION TECHNIQUES . . . . . 3
Ii . EXTRACTION PROCEDURES . . . . . . . . . . . . . . . . . . 10
III. FRACTIONATION AN!) DERIVATIZATION PROCEDURES . 20
IV. QUALITY CONTROL IN THE ORGANIC LABORATORY . . 25
V • GENERAL COMMENTS . . . • . . • . • . 30
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Workshop on
Sample Preparation Techniques for
Organic Pollutant Analysis
PART I CIPANTS
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 Barron
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
NERC—Cjncjnnati
Cincinnati, Ohio 45268
Dr. Frank J. Biros
Pesticide Effects Laboratory
NERC - RTP
Research Triangle Park, N.C. 27711
Dr. Joseph Blazevich
S & A Division
Region X
14515 SE 21st Place
Beilvue, Washington
Mr. Harvey W. Boyle
National Field Investigations Center
Building 53, Box 25227
Denver Federal Center
Denver, Colorado 80225
Mr. Mike Carter
Southeast Water
College Station
Athens, Georgia
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 Middlefleld Road
Menlo Park, California 94025
!(r. William L. Griffis
Consolidated Laboratory Services
NERC — Corvallis
200 SW 35th Street
Corvallis, Oregon 97330
P4r. Michael Gruenfeld
Edison Water Quality Research
Laboratory
Edison, New Jersey 08R17
Laboratory
Road
30601
98007
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PARTICIPANTS (Cant. )
Dr. Larry Harris
Analytical Quality Control
Laboratory
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 Funs ton 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 60225
Mr. James Lichtenberg
Method Development and Quality
Assurance Research Laboratory
NERC—Cjricinnatj
Cincinnati, Ohio 45268
James E. Longbottom
?tethod Development and Quality
Assurance Research Laboratory
NERC—Cjncjnnat i
Cincinnati, Ohio 45268
Mr. William Lay
Laboratory Services Branch
S & A Division
Region IV
Southeast Water
College Station
Athens, Georgia
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
Lab oratory
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 #1
Columbia, tissouri 65201
Dr. Emillo Sturino
S & A Division
Region V
1819 tlest Pershing Road
Chic ago, Illinois 60609
Mr. John Tjlstra
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
Laboratory
Road
30601
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PARTICIPANTS (Cont. )
Dr. Gilman 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 C. 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
Sabjne Island
Gulf Breeze, Florida 32561
iv
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1
INTRODUCTION
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 unon 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 blo—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 coi’ plex 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 apDly these new techniques to the analysis
of industrial—waste discharRes 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 eNphasis of
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the workshop was placed upon the problems of sami 1e collection,
extraction, and fractionation prior to detection c f the pollutants
of interest by the appropriate detection techninu s. ‘herever pos-
sible, methods or nrocedures were stressed that werc a’”licable to the
analysis for general classes of orr anic compounds as opposed to pro-
cedures for individual comnound identifications.
What follows Is a summation of the techniquus dt c!sse1 at the
workshop. Many of these are currently beinc’ 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 re nTr 1 irt analytical
quality control in the organic laboratory as wefl s a siirnatlon of
miscellaneous, qeneral coumients that were expressed t the meeting.
It is felt that the summary of this wor :sh n wi1 l serve as a
guide to current practices in the analysis for orp anic—chenica1 0i—
lutants, and draw attention to those areas where more information
is needed.
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I. SNrnLE COLLECTION AND pr Esr.RvATTm1
Sainnie collection and oreservation is an area where considerable
research and development is needed. There was general agreement amon
the workshop particinants that there are, at present, no definitive
c tiides to samnie collection and preservation for organic—pollutant
analysis. In addition, less than ten percent of the laboratories renre—
sented indicated that they routinely participate in the actual collection
of samples or orc anic analysis. This would indicate that very few
chemists have direct input into the nianning and conducting of sampLinc ’
oroc ranis. In this respect, there was unanimous agreement that the analyst
should participate in the design of the sample collection nrocess, par—
tf.cularly with respect to the preparation of sarrnle containers, check on
purity of solvents and reacents, 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 so”ie
groun within EPA should he assigned the task of nrerarin a samplin
nanual F or use in training and guiding sampling crews who are to collect
samples for organic analysis.
fly far, the largest number of samples analyzed by the various
laboratories are grab—water samples. Despite this ‘act, there seemed
to be little real. kno’iledce of the effects of collection method, con-
tainer materials, handlinc’ procedures, etc. on the ciualitv of the
restiltinc’ samr]e. 1Io ;ever, it should be erinhasi.zed that ciscussions
did not include the relatively well—develoned area o pesticide residue
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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. tost attendees agreed that glass bottles
or jars were nref erred, but one chemist suggested the nossibility of
sample contamination due to leaching of materials fron 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.
1ost attendees felt that teflon—cap liners should be used to avoic
sample contamination and losses, but a limited amount of evidence sug-
gests that some solutes, notably PCBs, may be lost to, or throuc’h teflon
liners. In these cases, aluminum—foil liners proved sunerior. Again,
research is needed in this area.
Some attendees pointed out that serious losses of solutes from
water samples may occur due to volatilization fror the water surface.
This effect has been particularly noticed with petroleum samples. A
recent paper by ‘ tackay and TJo].koff [ FJnv. Sci. “echnol. , 7, (ill (1971)1
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 interestjnr conciusions. For example, if we assume that the
sriple bottle cornflon]v used by EPA laboratories contains R50 ml of
liquid and 50 ml of air space, then at 4°C about 20 Percent of the
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Aroclor 1260 from an initially saturated solution will he found in
the air space. Also, since this is the equilibrium situation, shakinc ’
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
major source of error in the analysis of grab sannles for P03 9 , aro—
matics, alkanes, and other organic materials. Obviously, the smaller
the air space above the sample, the smaller the losses that nay 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 pronerly prepared (pre—
washed) containers to the sampling crews.
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Other sources of contamination are the caps used to sea] 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, reacwnts
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 compositino
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 iorked with
macroreticular resin columns. Those that had used resins agreed that
this approach to sampling seems to hold a great deal of nromise.
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In a recent example ( . Tindle, /1(2C ‘Yewletter, ‘ l9, October, 1973],
a mixed bed of Amberlite ‘ Afl—2 am! AD—7 (50:50 mixturc) 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 f low—
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?”
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(e) particulates on columns — “How should particulates be
handled? What are the effects of partial plugging?”
(f) elution procedures — “What is best method of elutin
columns? Are separation based on pH or solubility
feasible?”
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
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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 N. Gruenfeld, Env. So . Technol., 7, 636 (1973)], while
formalin was suggested for PCB—containing samples [ T. A. Bellar and
3. 3. Lichtenberg, “Some Factors Affecting the Recovery of PCB’s Frori
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 sariples are preserved by freezing by
almost all represented labs. A recent paper [ Butler, Pest. Pon tor. J.,,
6, 23 (1963)] reported the use of a mixture of 90 percent anhydrous
sodium sulfate and 10 percent Quso 030 (micro—f me 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.
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tI. 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 !7orkshop,
extraction techniques were discusscd for separating organic pollutants
from water and wastcxiater samples, tissue, bottom sediment, and sludge
samples.
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 1 steam
distillation.
The technique of direct aqueous—injection gas chromatography (CC)
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/i is adequate. The use
of pre—coluinns to prevent salts and other non—volatiles from damaging
the CC 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 ninimum 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,
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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 Nethod
of Test for Phenols in Water by Gas Liquid Chromatography” (D2580) and
for the analysis of volatile organic matter in water In their Hethod
(D2908). Additional methods of direct aqueous injection for organic
acids, nitrites, and aliphatic hydrocarbons are presently being pre-
pared by ASTh and others tD. Brown, I1QC 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 ellar reported the
use of nitrogen gas to purge volatile—organic components from water
samples. The evolverl or anics 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 teiiperature—pro r m conditions. The technique ha been
applied to a variety of c ilorinated and nor —chlorinated aromatic and
aliphatic solvents. Under anbient conditions, the recovery of relatively
Insoluble organic compounds has been found r’ore efficient than the
recovery of highly water—soluble compounds. Instead of collecting
the purged volatile—organics on a column, the materials may be cal—
lected in a cold trap. This technique has been used by several of the
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laboratories in attendance and is a relatively common technique in the
analysis of atmospheric samples.
Steam distillation can be used to reduce the sanpie 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 CC or other types of detection.
ilowever, possible hydrolysis of sample components must he 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 Uork—
shop participants were queried as to the most coimnon types of solvents
used for this purpose and it was found that the solvents most commonly
used were methylene chloride or chloroform, followed by ethyl ether,
hexane, methylene chioride—hexane, and finally by ethyl ether—hexane
mixture. Other solvents that were mentioned but not widely used, were
carbon tetrachlorlde 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. 7 lowever, 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
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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 p1-I 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 separatory funnels or a magnetic stir-
ring device. The niagentic 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—277B “Solvent Extraction of Organic
Matter from Water”. This method describes a general approach that will
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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 ultra onic 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—water 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 emulel—
fled 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 extractod from environmental samples into the
organic layer. In order to avoid sulfur interference, the sulfur may be
removed with mercury or copper powder (Pull. Pnviron. Cont. cm Toxic!.,
6, 9(1971).
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An a1tern ite approach for recovery of organic pollutants from
iater and wastewater is a sorption on organic resins or activated
carbon followed by solvent extraction of the resin or carbon to desorh
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 p11 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.; ha ever, 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
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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.
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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. Agr. 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. A9rr. 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 chromatographic column and extracted by elution
with a solvent such as acetone, methanol, or acetone—haxane (1:1) [ (Pull.
Envir. C’ontcjn. Toxi., 7, 1151, (1972) and Southeast Water Laboratory,
EPA, Athens, Georgia, Method No. SP—8/71J. An alternate technique Is
freeze drying the tissue samples. Dr. A. Wilson of EPA’S Cuif Breeze
Laboratory has used this method for preparation of phytoplankton samples.
Tissue samples can also be extracted by use of a soxhiet extrac-
tor. This seems to be about as commonly applied as the column extrac-
tion technique. Some of the solvents employed for soxhiet extraction are
petroleum ether, methylene chloride, acetone—hexane, niethylene chloride—
hexane, acetonitrile, ethyl acetate, and acetone—benzene. The use of
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phosphoric acid acetone (1:2) has been used for the extraction of
pentachiorophenols.
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 soxhiet 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 soxhiet extraction. Solvents normally employed are
acetone-hexane, acetonitrile—hexane, methylene chloride, acetonitrile,
ethyl acetate, and acetone—benzene. Soxhiet extraction of sediment
samples has been described many times (“The Identification and teasure—
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
treatment.
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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 coin—
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 he done to deterriine which extraction procedure, if
any, is superior. However, an even greater area of concern is the iido
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.
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III. FRACTIONATION ANfl DERIVATIZATION PROCEDURES
Samples that are too complex to be separated under normal ( C con-
ditions are usually subjected to some form of fractionation durinc , 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. Chem. 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 20!I 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
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trichiorinated alkanes up to seven carbons long that complicate the CC
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 CC—MS Analysis
of Organics in Water” (EPA—R2—73—277).
Other groups feel that trimethylsilyl (TMS) derivatives give more
definitive mass spectra than methyl derivatives. They recommend BSTFA
(N,O—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)1.
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 dichioroaniline isomers and other nitrogen
containing compounds in industrial effluents were identified by
NFIC—Denver after conversion to T 1S derivatives. Several aromatic
amines from biological sources were reported as analyzed in good
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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 axnines 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 CC on OV—1Ol. 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 CC was to separate
the oil into all.phatic, aromatic and oxygenated fractions by eluting
from silica gel with isooctane, benzene and 1:1 chloroform—methanol by
the method of flosen and ?tiddleton [ Ana1 . 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
solvent.
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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
areas.
Another method mentioned for detecting specific compound groups
was the use of CC subtraction columns. These are short lengths of
tubing containing a chemical that removes specific compounds. They
are placed between the CC injector and the column. Boric acid sub-
tracts alcohols, o—dianisjdine subtracts aldehydes and ketones, phos-
phoric acid subtracts epoxides [ Beroza, JAOI1C, 54, 251 (1971); see
also C zem. 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
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columns bleeding enough to show up later in CC—MS analysis of the
individual fractions.
Of at least ten LC’s in EPA labs, four have been bought within
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 chiordane. 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. NPIC—Denver plans to
evaluate the application of gel permeation to industrial effluents.
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IV. QUALITY CONTROL IN TIlE ORGANIC LABORATORY
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 T’astewater 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 rultiple colunn gas chromatography. The latter techn1qur
is enhanced when a sernispecific detector such as the PP or Coulsen
riicro—coulometric can be used. Obviously in all cases of instrumental
andysis, close control must be imintained of the instrumental parameters.
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In regard to the quantitative aspects of quality control, both
replicate and spiked sample analyses must be performed periodically
to assure the precision a d 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 jig/i 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
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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, eluted
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.
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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 carhon—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 Tlorkghop
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 quantitatlon 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
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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.
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V. GENERAL CONENTS
A variety of items not covered in the preceding chapters were
brought up during the general discussion period of the t lorkshop. Sorte
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 Peg -Cater, Vol. 38, No. 173,
Sept. 7, 1973)]. Much of this interest was 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, aidrin, die ldrin, toxaphene, etc. However,
little information was available regarding the analysis for benzidine
(4,4—diaminodiphenyl) and its salts.
The MDQARL is presently working on methods for benzidine. A color—
metric method is currently recommended [ TI. A. El—Dib, JAQAC, 54, (6),
1383 (1971)]; however, it is not specific for benzidine. Uork is pre-
sently underway on a thin—layer modification of this method and a CC
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.
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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 frori the Surveillance Network of the F’WPCA, and
no benzidlne was found.
The 1DQARL has found that the free base can be quantitatively
extracted front water at pH 10 with chloroform. ‘later 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 ainines, 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 Uorkshop 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.
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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 organocadmiun
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, CC 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
workable.
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 AST?Y
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,
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i.e., phthalate plasticisers [ D. L. Stalling, et. al., L’nvironmental
health Proopectives, 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., 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—l, Dexil, and Apiezon L. Undoubtedly, others are available.
Liquid chromatography has also been used and appears to hold considerable
promise [ N. F. Eves and L. Giuffrida, J 1 4OAC, 55, (4), 757 (1972)]. In
tissue samples, polynuclear aromatic hydrocarbons can be identified by
fluorescence following a rigorous clean—up procedure [ 3. W. Howard,
et. al., JAOAC, 51, 122 (1968); AOj1C kthods, 1 1th Ed. 21.001, 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 Plethods. The MDQA.RL
has used TLC procedures to identify polyoxyethylene—type detergents in
CCE extracts from carbon filters [ ASTII Special Tech. Pub. No. 44R, p 7
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(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 [ 1). J. tYildish, and W. C. Carson, Fieheries Reaecrt’ch
Board of Canada 1?eport, Series No. 1212, October (1972); 1). 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
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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.
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