Acr ? iC^UNiTtD STATES ENVIRONMENTAL PROTECTION AGENCY
hrt\ _ -' i.w*.
. Guidance on Petroleum Refinery Waste Analyses for Land
>u ' Treatment Permit Applications
John Skinner, Director^/) (
Office of Solid Waste /l*^
T0 Hazardous Waste Fermi tL/Branch Chiefs,
Regions I-X
Introduction
The purpose of this memo is to provide permit writers
guidance on evaluating petroleum refinery waste analyses submitted
in land treatment permit applications. A list of Appendix
VIII hazardous constituents suspected to be present in petroleum
refinery wastes and a special analytical method for refinery
wastes are provided.
Background
The general Part B information requirements specified
under $270.14(b) require the submittal of (1) chemical and
physical analysis data on the hazardous wastes to be handled
at the facility including all data that must be known to treat,
store, or dispose of wastes properly in accordance with Part
264, and (2) a copy of the waste analysis plan. In addition,
the specific information requirements under §270.20 require an
owner/operator of any facility that includes a land treatment
unit to submit "a list of hazardous constituents reasonably
expected to be in, or derived from, the wastes to be land
treated based on waste analyses performed pursuant to §264.13."
Also, S270.20(a) stipulates that the description of the treatment
demonstration plan must include a list of potential hazardous
constituents in the waste.
Because the design and management of a land treatment
unit is based on the goal of attaining treatment of hazardous
constituents (i.e., constituents listed in Appendix viii), it is
very important that the presence of these constituents in the
land treated wastes be accurately identified and quantified.
This is best achieved through a comprehensive waste analysis
for all Appendix VIII constituents. However, due to the cost
and analytical difficulties associated with these analyses,
many applicants have submitted requests to conduct analyses
for some subset of Appendix VIII, which are "reasonably expected
to be in or derived from the wastes to be land treated." To
date, the majority of wastes proposed for land treatment have
been petroleum refinery wastes, specifically the listed wastes
K048-K052.
If* f~
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The evaluation of these Appendix VIII subsets for each land
treatment application has been difficult due to the lack of
published information on specific organic compounds In refinery
wastes, and also due to the variability of waste characteristics
within the refinery industry. However, OSW has gathered sufficient
information from EPA research studies, in—house waste studies
and analyses, and refinery process evaluations to develop a
conservative list of hazardous constituents that are suspected
to be present in petroleum refinery wastes. This list is
proviced in Attachment 1. This list should be used by permit
writers as a guide in determining which constituents may and
may not be eliminated from consideration when completing waste
analyses for a land treatment permit application. Additional
explanation of the derivation and use of this list is provided
below.
Derivation and Use of List
The list of hazardous constituents suspected to be present
in refinery wastes was derived from a review of data on petroleum
refinery wastewater and sludge characteristics from the following
sources: (1) literature, particularly EPA research reports:
(2) in—house waste analyses completed by EPA research laboratories;
(3) preliminary data from the OSW refinery waste study; and
(4) an evaluation of petroleum refinery processes. Although
these four sources were used, the data base on specific hazardous
organic constituents in sludges was still limited. Considerable
weight was placed on wastewater data as indicators of sludge
characteristics (e.g., API separator sludge).
Also, the list in Attachment 1 is a generic list developed by
combining waste analysis data on all five listed refinery wastes
(X049—K052). Due to the lack of extensive data, no attempt
was made to differentiate between the characteristics of these
five refinery wastes. Until sufficient information is available
to allow development of separate lists for each waste, the
attached list should be considered applicable to dissolved air
flotation float (1 (048), slop oil emulsion solids (K049), heat
exchanger bundle cleaning sludge (1(050), API separator sludge
(1(051), and leaded tank bottoms (1(052).
To compensate for the limited data base and variability among
refineries, the attached list is purposely comprehensive.
It includes a total of 89 hazardous constituents or groups
of constituents (e.g., trlchlorobenzenes). All of these con-
stituents have been identified as possibly being present in
the above referenced wastes. Many of the compounds on the
list may be present at low concentrations and others may not
be present at all in certain wastes at some refineries.
The permit writer should use the attached list as a guide
to the Appendix VIII constituents that should be addressed in
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the up—front waste analyses and waste analysis plans for Part B
applications that propose land treatment of petroleum refinery
wastes. A permit applicant may further refine this list by
providing detailed evidence that certain hazardous constituents
cannot be present in the listed wastes at that particular
refinery. In most cases, i owever, waste analysis data on the
constituents listed in Attachment 1 will be necessary to make this
showing.
Analytical Methods
To assist In the analysis for specific organic constituents
in petroleum refinery wastes, OSw has developed a column cleanup
procedure which is provided in Attachment 2. This draft method
is used specifically to separate semivolatile a.liphatic, aromatic,
and polar compounds in the waste matrix. The method should be
used only by experienced residue analysts. Volatile compounds
are determined using method 8240 with PEG (tetraglyme) Extraction.
Test method 3050 should, be used for all metal analyses. These
methods are described in SW—846.
Relationship to Delisting and Listing Efforts
Finally, the attached list is consistent with the waste
analysis information that EPA has requested from delisting
petitioners. Many petroleum refinery operators who are preparing
Part B applications for land treatment facilities also have
submitted delisting petitions to the Agency for one or more of
their wastes.• It is important that the waste analysis data
requested by the Agency for permitting and delisting be consistent,
although there may be differences in the extent of data necessary
in certain cases. Therefore, the list of Appendix VIII constituents
provided in Attachment I is also being used in refinery delisting
actions. Additional information on non—Appendix VIII constituents,
however, is being collected as part of OSW’s new waste assessment
and listing efforts for petroleum refineries. These compounds,
which are listed at the end of Attachment 1 for your Information,
may be added to Appendix VIII in the future. Although it Is
not required at this time, permit applicants should be encouraged
to provide information on these waste constituents.
If you have any questions on the listing of specific
hazardous constituents in Attachment 1 or on the recommended
test methods, please contact Ben Smith (382—4791) of the Waste
Identification Branch. Other questions pertaining to the use
of the above guidance In permitting land treatment facilities
should be directed to Mike Flynn (382—4489) of the Land Disposal
Branch.
Attachments
cc: Jack Lehman 1att Straus
Fred Lindsey Bruce weddle
Ken Shuster Peter Guerrero
Eileen Claussen
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ATTACHMENT 1
Appendix VIII Hazardous Constituents Suspected to be Present in Refinery Wastes
**Acetonjtrjle (Ethanenitrile)
**Acrolein (2—Propenal)
**AcryTonjtrlle (2—Propenenitrile)
Aniline (Benzenamine)
Antimony -
Arsenic
Baium
Benz (c) acridine (3,4—Benzacridine)
Benz (a) anthracene (1,2-Benzanthracene)
**Benzene (Cyclohexatriene)
Benzenethiol (Thiophenol)
Benzidine (1,1-Biphenyl—4,4diarnine)
Benzo(b)fluoranthene (2,3-Ben,zofluoranthene)
Benzo(j )fluoranthene (7 ,8-Benzofluoranthene)
Benzo(a)pyrene (3 ,4-Benzopyrene)
•*Benzyl chloride (Benzene, (chioromethyl)-)
Beryllium
Bis (2—chioroethyl) ether (Ethane, 1,1—oxybis (2—chioro—))
Bis (2—chioroisopropyl) ether (Propane, 2,2—okybis (2—chioro—))
•eBis (chioromethyl) ether (Methane, oxybis (chloro))
Bis (2—ethyihexyl) phthaIate (1,2—Benzenedicarboxylic acid, bis (2-ethyihexyl) ester)
Butyl benzyl phthalate (1,2-Benzenedicarboxylic acid, butyl phenyimethyl ester)
Cadmium
Carbon disulfide (Carbon bisulfide)
p-CM oro-m—cresol
e*Chlorobenzene (Benzene, chioro—)
**Chloroform (Methane, trichloro-)
**Chloromethane (Methyl chloride)
2— Chloronapthalene (Naphthalene, beta—chioro—)
2-Chiorophenol (Phenol, o-chloro-)
Chromium
Chrysene (1 ,2-Benzphenanthrene)
Cresols (Cresylic acid) (Phenol, methyl—)
**crotonaIdehyde (2-Butenal)
Cyanide
.Oibenz(a ,h)acridine (1,2,5,6—Oibenzacridine)
Dibenz(a,j)acrldine (1,2,7,8—Dibenzacr ldine)
Dibenz(a,h)anthracene (1,2,S,6—Dibenzanthracene)
7H-Dibenzo(c,g)carbazole (3,4,5,6-Dibenzcarbazole)
Dibenzo(a ,e)pyrene (1,2,4 ,5—Di benzpyrene)
Dibenzo(a,h)pyrene (1,25,6—Dibenzpyrene)
Dibenzo(a,i )pyrene (1,2,7,8-Dibenzpyrene)
1 ,2-Dibromoethane (Ethylene dibromide)
Di—n-butyl phthalate (1,2—BenzenedicarboxylIc acid, dibutyl ester)
*Dj chi orobenzenes
*t ,2-Dichloroethane (Ethylene dichioride)
*ttrans_1,2_Djchloroethene (1,2-Dichiorethylene)
1 ,1—Dichloroethylene (Ethene, 1 ,1—dichloro—)
**Djchloromethane (Methylene chloride)
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2
t Di chioropropane
Dichioropropanol
Diethyti phthalate (1,2 BenzenedicarboxyliC acid, diethyl ester)
7 ,12_Dimethyl —beflz(a)aflthracefle
2,4_DimethyiPheflOl (Phenol, 2,4-dimethyl-)
Dimethyl phthalate (1,2—Benzeriedicarboxylic acid, dirnethyl ester)
4 ,6_Dinitro -o —cresol
2,4 DinitrOPheflO1 (phenol, 2,4-nitro-)
2fra_Dinitrotoluene (Benzene, 1 —methyl—2,4—din;trO—)
Di—n—oCtyl phthalate (1,2 —Benzenedicarboxylic acid, dioctyl ester)
**1,4_Dioxane (1,4-Diethylene oxide)
1,2 Diphenyihydra2ifle (Hydrazine, 1,2-diphenyl—)
thyleneimifle (Azridine)
etEthylene oxide (Oxirane)
Fluoranthene (Benzo (j,k) fluorene)
**Formal dehyde
Hydrogen sulfide (Sulfur hyd 9de)
Indeno (1,2,3-cd)pyrene (1 10(1,2_phenylene)pyrefle)
Lead
Mercury
Methanethiol (Thiomethanol)
3—Methyichiolanthrefle (Benz(j)aceanthrylene, l,2_dihydro_3 methyl—)
Methyl ethyl ketone (MEK) (2-Butanone)
NaphthaIene
Nickel
p-Nitroaniline (Benzenamine, 4—nitro-)
Nitrobenzene (Benzene, nitro—)
4—Nitrophenol (Phenol ,pentachI cr0-)
PentachiorophenOl (Phenol, pentachioro—)
Phenol (Benzene, hydroxy—)
Pyridine
Selenium
* ,**Tetrachloroethafles
**Tetrachloroethylene (Ethene, lj,2,2—tetra chioro-)
**Toluene (Benzene, methyl—)
Tri chiorobenreneS
*,**Tri chioroethaneS
**Trlchloroethefle (Trichioroethylefle)
*Irjchlorophenol s
Vanadium
* If any of these groups of compounds are found, the specific
Isomers listed in Appendix VIII should be identified.
** Use Test Method 8240 for these volatile compounds.
Use Test Method 3050 in SW-846 for all metals; see
Attachment 2 for semivolatile organic compounds.
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Non—Appendix VIII Constituents of Concern (may be added to App. VIII )
Cobalt Indene
1-Methylnapthalene 5-Nitro acenaphthene
Styrene Quinoline
Hydroqulnone Phenanthrene
Anthracene Pyrene
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ATTACHMENT 2
Column Cleanup of Petroleum Wastes
I ntroduct ion
The following procedure is intended for application to the
analysis of semivolatile organic compounds in oily waste
samples. Its application is necessary in those cases where
Lhe conventional cleanup procedures (Methods 3510, 3520,
3540, 3550) fail, to provide suitable detection limits (approx-’
imately loppm) for the semivolatile compounds specified in
Attachment 1. Analysis of the cleaned—up extracts should be
performed according to Method 8270, a capillary GC/MS technique.
It should be noted that this procedure is in draft form. It
may be modified as more experience is gained.
Cleanup Techniques
It is anticipated that after a sample is subjected to
conventional extraction procedures (Methods 3510,3520, 3540,
and 3550) or after dilution, a cleanup step may be required
to remove matrix interferences and yield acceptable detection
limits for compounds of interest. Determination as to whether
an extract needs to be cleaned can usually be provided by either
examination of the sample itself or by knowledge of the
particular waste stream that was sampled. It is also possible
to estimate whether or not the extract is suitably clean for
GC/MS analysis. An aliquot of the methylene chloride extract
can be evaporated to dryness and the total amount of material
in the aliquot weighed. In general, if the extract contains
less than a few milligrams of material per millilitre of
solvent, .it is probably clean enough for capillary CC/MS. If
it contains more materials, it will likely require additional
preparation.
In most instances, son e type of cleanup technique will be
necessary in order to achieve suitably low detection limits
for the target compounds. If much aliphatic material exists
in the sample it will mask the compounds of interest. Mere
dilution will not remedy the situation as detection limits
are raised by the dilution.
If acidic compounds such as phenols are suspected of
being present in the sample, a separate fraction containing
these acids can be created using the organic extract obtained
above. Methods 3530, a base/neutral acid cleanup extraction
technique, may be applicable to the cleanup of certain sample
types. Modifications to Methods 3530 are as follows:
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a) In Section 7.6, the organic and aqueous phases are both
treated as containing compounds; and
b) Section 7.15 will not be necessary.
The aqueous phase, when transferred to organic solvent after
Section 7.13, will contain acidic compounds. The orç,anic
phase contains basic and neutral compounds. In most instances,
the acidic fraction will be clean enough for CC/MS ar.alysis.
The base/neutral extract, however, may require further cleanup.
Thus, a cleanup procedure ha been devised for base/neutral
extracts that minimizes the interferences caused by high
concentrations of aliphatic and polymeric materials.
Although the cleanup procedure is thoroughly described in
the next section, one generally proceeds as follows. The sample
is subjected to cieanup by placing a representative aliquot
of the sample on an al 9 mina column and successively eluting
with hexane, methylene chloride, and diethyl ether to yield
3 fractions containing the aliphatic (hexane fraction), aromatic
(methylene chloride fraction) and polar compounds (ether
fraction). The methylene cloride fraction is then concentrated
to about 1 ml. and then is analyzed by CC/MS for the compounds
of Interest. The hexane concentrate can be screened by
GC/MS to determine if compounds were eluted into the hexane
fraction. However, this usually will not be required. If
polar compounds are of interest, the ether fraction is also
analyzed.
Quantitation of the semivo]atile constituents in Attachment 1
is to be performed using the reverse search technique.
Additionally, tentative identification should be attempted
for the ten organic compounds detected at the highest concen-
trations. Identifications should be made via a forward
search of the EPA/NIH mass spectral library. Concentrations
should be approximated by comparison of the compound response
to that of the closest eluted internal standard. A procedural
blank, matrix spike, and duplicate should be analyzed for
every batch of samples.
Accuracy and precision control charts should be maintained
for indicator constituents. The percent recoveries of spiked
surrogate standards for a given sample type should be plotted
versus sample identification number. Table 1 contains a list
of the surrogate compounds to be employed for the analysis of
semivolatile organic compounds, and recovery limits. Recovery
limits are based upon obtaining a final extract sufficiently
clean, such that the surrogate compounds should be present at
50 ppm or higher in the extract. If dilution of the sample is
still required, detection of the surrogates may be difficult
and the associated recoveries imprecise or non—existant.
Such samples should be spiked with higher surrogate levels
and resubjected to the cleanup procedure.
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Table 1. Surrogate Standards for Semivolatile Organic
Compound Analysis
Recovery Limits
Acid surrogates
phenol—d 5 40—115%
2—f luorophenol
2,4 ,6—tribrornophenol
Base/neutral surrogates
nit robenzene—d 5
5—fluorobiphenyl 50—120%
terpheny l—d14
acridine—d 9
pyrene—d 10
The precision control chart should consist of the percent
difference for indicator constituent concentration determined
in duplicate samples of a given sample type versus sample
identification numbers.
Column Clean Up of Petroleum Wastes
Scope and Application
This method is used to cleanup samples containing high
levels of aliphatic hydrocarbons, such as wastes from petroleum
refining. It is used specifically to separate aliphatics,
aromatics, and polar compounds in the waste matrix. This
method is applicable to API separator sludges, rag oils, slop
oil emulsion, and other oily wastes derived from petroleum
refining. This method is recommended for use only by or
; under close supervision of experienced analysts.
Summary of Method
Take a 200 mg aliquot of the waste/methylene chloride
concentrate from step 7.13 of Method 3530. Dissolve the
aliquot in r exane and spike with 10mg each of d 9 —acridine,
d 5 —nitrobenzene, d 5 —phenol, 2—fluorobiphenyl, tribromophenol,
d14—terphenyl, 2—fluorophenol, and dlO—pyrene. Apply the mixture
directly to the alumina column.
The column is eluted sequentially with hexane, methylene
chloride, and diethyl either and the corresponding three
fractions are collected. An aliquot of the CH 2 C I 2 fraction
is evaporated under a gentle stream of nitrogen and weighed to
determine the appropriate concentration factors prior to
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GC/MS. If pyrene or terphenyl is recovered at.less than 50%,
the procedure should be repeated.
Interferences
Matrix interferences will likely be coextracted from the
sample. The extent of these interferences will vary considerably
from waste to waste depending on the nature and diversity of
the particular waste being analyzed. The use of additional
cleanup extractions can be used as necessary for specific
compound identification and quantitation.
Apparatus
Glass Column: 30 cm long x 1 cm I.D. with glass frit or
glas5 wool and stop clock.
Aluminum weighing boats: Approximately 2 in. in diameter.
Analytical Balance: Capable of weighing to +0.5 mg.
Concentrator Tube, KD, 10 ml
Evaporative Flask, KD, 250 ml
Snyder Column, KD, three—ball micro
Snyder Column, KD, two—ball micro
Steam Bath
Boiling Chips:
10—40 mesh carbarundum. Heat to 450°C for 5—
10 hours.
Syringe: 1 ml glass
50 ml beaker
250 ml beaker
Reagents
Hexane: Distilled in glass (B&J) or equivalent
Methylene Chloride: Distilled In glass (B&3) or equivalent
Diethyl Ether: Distilled in glass (B&J) or equivalent
Alumina: Dried overnight at 130°C, neutral 80—325 MCB
chromatographic grade
Sodium Sulfate: Washed with CH 2 C1 2 and heated to 150°c for 4
hours
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Procedure
weigh Out 10.0 gm of alumina and add to the chromatographic column
that is filled to about 20 rnL with hexane.
Allow the alumina to settle and then add 0.5 gm sodium sulfate.
Let the solvent flow such that the head of liquid in the column
is ahout 1 cm above the sodium sulfate layer. Stop the flow.
Add the aliquot equivalent to 100—200 ing of material.
Start the flow and elute with 13 ml of hexane. Collect the
effluent in a 50 beaker. Label this fraction ualiphaticsfl
Elute the column with 100 ml of methylene chloride and collect
the effluent in a 250 ñ l beaker. Label Waromaticsll
Elute the column with 100 ml of diethyl ether and collect the
effluent in a 250 ml beaker. Label wpolarsw.
Weigh three sample boats to the nearest 0.5 mg. Reduce the
volume of each fraction using the KDs to between 1 and 5 ml.
Record the volume of each and place 1/2 of each sample in the
respective boat.
Evaporate the liquid in each boat under a gentle stream of
nitrogen. Reweigh each boat and record the weight of each fraction.
Calculate the weight of each fraction as a proportion of the
total sample. For example, fraction I is 56.3 mg, fraction 2
Is 25.4 ing, and fraction 3 is 85.0 mg.
Calculate the amount of sample in the fractions and adjust
the volumes so in)ection will permit determination of various
components on scale
12.7 mg/2500 ul 5.1 ug/ul
Dilute each of the three fractions obtained by a ratio so
that the sample entering the capillary column does not exceed
2.5 ug. For example, if the calculated weight of the fraction
as a proportion of the total sample is 12.7, and the amount of
sample in the fractions is 5.1 ug/ul as in the above example,
dilute the sample 1:1 with methylene chloride.
Quality Control
Before processing any samples, the analyst should demonstrate
through the analysis of a distilled water method blank that
all glassware and reagents are interference—free. Each time a
set of samples is extracted or there is a change In reagents.
a method blank should be processed as a safeguard against
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chronic laboratory contamination. The blank sample should be
carried through all stages of the sample preparation and measure-
ment. Standard quality assurance practices should be used
with this method. Laboratory replicates 3hould be analyzed
to validate the precision of the analysis. Fortified samples
should be carried through all stages of sample preparation
and measurement; they should be anlayzed to validate the
sensitivity and accuracy of the analysis.
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SKINNER LIST
Metals Semivolatile Base/Neutral Extractable
ComoourlCS
Antimony
Arsenic Anthracefle
Barium Berizo (a) arnhracene
Beryllium Berizo (b) fluorarnhene
Cadmium Benzo (k) fluoranthene
Chromium Benzo (a) pyrene
Cobalt Bus (2-ethylhexyl) phthalate
Lead Butyl benzyl phthalate
Mercury Chrysene
‘J uckel Diberiz (aM) acridine
Selenium Dibenz (aM) anthracene
Vanadium DichlorobenZefles
Diethyl phthalate
loI atijg 7,1 2.Dimethylbenz (a) anthracene
3enzene Dimethyl phthal ate
Carbon disulfide Di (n) butyl phthalate
ChIorobenZer e Di (n) octyl phthalate
Chloroform Fluoranthefle
1 2.Dichloroethafle Indene
4-Dioxane Methyl chryserie
Ethyl benzene 1-Methyl naphthalene
Ethylene dibromide Naphthalene
Methyl ethyl ketone Phenanthrer ie
Styrene Pyrene
Toluene Pyridine
Xylene Quinoline
Semivolattle Acid- Extractable Comooufl
Benzer iethiOl
Cresols
2.4-DumethylPheflol
2 .4 DinitrOPheflOl
4-Ni trophenol
Phenol
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Office of
Research and
Development
Office of Solid
Waste
and Emergency
Response
EPAI54O/4-9 1/O0i
February 1991
P EPA
Ground-Water Issue
SOIL SAMPLING AND ANALYSIS FOR
VOLATILE ORGANIC COMPOUNDS
1. E. Lewis, A. B. Crockett, R. L Siegrist, and K. ZaITabi
The RegionaJ Superfund Ground Water Fo-
rum is a group of ground-water scientista that
represents EPA’s Regional Superfund Of-
fices The forum was organized to exchange
up-to-date information related to ground-
water remediation at Superfund sites. Sam-
pling of soils for volatile organic compounds
(VOCs) is an issue identified by the Ground
Water Forum as a conoem of Superfurid de-
osion makers.
A group of saentis actively engaged in
method development research on soil sam-
pling and analysis for VOCs gathered at the
Enwonmentai Monrtonng Systems Labora-
tory in Las Vegas to examine this issue.
Members of the committee were
R. E. Cameron (LESC). A. B. Crockett
(EG&G), C. L Geriach (LESC), T. E. Lewis
(LESC), M. P. Maskarinec (ORNL),
B J. Mason (ERC), C. L Mayer (LESC),
C Ramsey (NEIC), S. R. Schroedl (LESC),
R L Siegnst (ORNL), C. G. Urchin (Rutgers
University). L. G. Wilson (University of
Arizona), and K. Zarrabi (ERC). This paper
was prepared by The Committee for EMSL.
LV’s Monitoring and Site Charactenzation
Techmcal Support Center, under the direction
of T. E. Lewis, with the support of the
Superfund Technical Support Project For
further informaton contact Ken Brown, Center
Director at EMSL-LV, FTS 545-2270, or T. E.
Lewis at (702) 734-3400.
PURPOSE AND SCOPE
Concerns over data quality have raised many
questions related to sampling soils for VOCs.
This paper was prepared in response to some
of these questions and concems expressed
by Remedial Proiect Managers (RPMs) and
On-Scene Coordinators (OSCs). The follow-
ing questions are frequently asked:
1 Is there a specific device suggested for
sampling soils for VOCs?
2. Are there significant losses of VOCS when
transfernng a soil sample from a sampling
device (e.g., split spoon) into the sample
container?
3. What is the best method for gettIng the
sample from the split spoon (or other
device) into the sample container?
4. Are there smaller devices such as
suboore samplers available for coIle ing
aliquots from the Larger core and effi-
ciently transfernng the sample into the
sample container?
5. Are certain containers better than others
for shipping and storing soul samples for
VOC analysis?
6. Are there any reliable rleservaxn proce-
dures for reducing VOC losses from sod
samples and for eztendng holdIng tImes?
Thle p er La intended to famdlartze RPMs,
OSCa, and field personnel with the ainern
stale of the sdence and the current thinking
concerning sampling soule for VOC analysis.
Guidance is provided for seledlng the most
effectIve sampling devIce for collectIng
Superfisid T.chnology Support Center
for Uonftortng and Site C*wactertratlon
Envfronm.ntal MonItoring Systems
Laboratory Las Vegas, NV
United States
Environmentaj Protection
Agency
/\
=
Pnritso on R*,, ’rled Paper
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samples from soil mati ’IceS. The techniques for sample collec-
tion, sample han ifl9. oontelneflDflg, SUPfl Oflt, and storage
desa’.bed paper reduce VOC losses and generally
provide more repreSefl UVe samples for volatile organic analy-
ses (VOA) than techniques in current use. For a discussion on
the proper use of sampling equipment the reader should refer
to other sources (Adiar, 1974; U.S. EPA. 1983: U.S. EPA.
1986a).
Sod, as referred to in this report, encompasses the mess
(surf and &Esurt ) of unconsolidated mantle of weath-
ered rod and loose matenai tying above solid mdc. Further, a
distinction must be made as to what fr on of the unconsoli-
dated material is soil and what fra ion is not. The soil compo-
nent here is defined as all minerai and naturally o .zmng
organic matenai that is 2 mm or less in we. This is the size
normally used to differentiate between soils (consisting of
sands, ailta, and days) and gravels.
Althou i numerous sampling situations may be encountered,
this paper focuses on three broad categories of sites that might
be sampled for VOCs:
1. en test pit orU’endi
2. Swfane soils (c5ftin depth)
3. Subsurface soils (>5 ft in depth)
INTRODUCTION
VOCs are the dass of compounds most commonly encoun-
tered at Superfund and other hazardous waste sites (M oy,
1985; Plumb and Pjtchford, 1985; Plumb, 1987; Ameth at al.,
1988). Table 1 ranks the compounds most commonly encoun-
tered at Superfund sites. Many VOCs are considered hazard-
ous because they are mutagensc, carcinogenic. or teratogenic,
arid they are commonly the controlling contaminants in site
restoration protects. Decisions regarding the extent of contaim-
nation and the degree of deanup have far-reaching effects;
therefore, it is essential that they be based on urate mea-
surements of the VOC concentrations present VOCs. how-
ever, present sampling, sample handling, and analytical diffi-
culties, especially when encountered in sods and other solid
matrices.
Methods used for sampling soils for volatile orgaruc analysis
(VOA) vary widely within and between EPA Regions, and the
recovery of VOCs from soils has been highly variable. The
source of variation in analyte recovery may be associated with
any single step in the process or all steps, induding sample
collection, transfer from the sampling device to the sample
container, sample stuprnent. sample preparation for analysis,
and sample analysis. The strength of the sampling chain is only
as strong as rts weakest link sod sampling and transfer to the
container are often fl e weakest links.
Sample colle on and handling activities have large sources of
random and systematic errors compared to the analysis itself
(Barcelona, 1989). Negative bias (i.e., measured value less
than true value) is perhaps the most significant and most
dtffiaitt to delineate and control. This error is caused primarily
by loss through volatlhzation dunng soil sample collection,
storage, and handling.
TABLE 1. RAM(BIG OF GROUP WA1 CONTA 4ANTS BASED
ON FREQU9 ICY OF DETECTiON AT HAZARDOUS WASTE
I 9 5
Con
te Uo
Tnddo m e f iene(V)
51.3
Tead oro ’iene (V)
36.0
12-Uw d methene(V)
29.1
ct &4m( )
284
1,1- il c ioethene(V)
252
Meth 4enedLndo(V)
.
192
1,1,1-Tii . ie(V)
18.9
1,1- ue(hane (V)
17.9
12-Do e fw (V)
142
Phenol (A)
13.6
Aoib ie(V)
12.4
ToIiene(V)
11.6
b i s-(2- y1)pttha l (B)
113
Beraene(V)
11.2
Wi 1 ói
8.7
V - e, A • d . J , B •
Sciz PUTt d P al (198
There are currently no standard procedures for sampling souls
for VOC analyses. Several types of samplers are available for
collecting in t (undisturbed) samples and bulk (disturbed)
samples. The selection of a particular device is site-specific.
Samples are usually removed from the sampler and we placed
in glass tars or vials that are then sealed with Teflon-lined caps.
Practical experience and recent field and laboratory research,
however, suggest that procedures such as these may lead to
significant VOC losses (losses that would affect the utility of the
data). Hanisch and McDevitt (1984) reported that any
heac [ cpece present in the sample container will lead to desorp-
tion of VOCs from the soil partides into the hear peoe and wifl
cause loss of VOCs upon opening of the container. Siegnst and
Jennsen (1990) found that 81% of the VOCs were lost from
samples containerized in glass tars sealed with Teflon-lined
caps compared to samples immersed in methanol in ars.
FACTORS AFFECTING VOC RETENTION AND
CONCENTRATION IN SOIL SYSTEMS
Volatile organic compounds in sod may coexist in three phases:
gaseous, liquid (dissolved), and solid (sorbed). (Note: Sorbed
is used throughout this paper to encompass physical and
chemical adsorption and phase partitioning.] The sampling,
identification, and quantitation of VOCs in soil matrices are
complicated because VOC molecules can coexist in these
2
-------
— -.
three phases The interactions between these phases are
illustrated in Figure 1 The phase distribution IS Controlled by
VOC physicocherrilCal properties (e g., solubilty, Henrys
constant), soil properties, and environmental vanables (e g,
soil temperature, water content, organic carbon content)
0l
a- I
Oi
( 1)1
I.
Figure 1 Equulubnum relationships for phase partitioning of
VOCs in soil systems See Table 2 for definitions
of abbreviations
The factors that affect the concentration and retention of VOCs
in soils can be divided into five categones: VOC chemical
properties, soil chemical properties, sod physical properties,
envirorinientaj factors, and biological factors. A bnef summary
of VOC, soil, and environmental factors is presented in Table 2,
which provides an overview of the factors that interact to control
VOCs in the sod environment at the time a sample is collected
The cited references provide a more detailed discussion The
chemical and physical properties of selected VOCs are further
descnbed in Table 3 Note that many of these properties have
been determined in the laboratory under conditions (e.g,
temperature, pressure) that may differ from those encountered
in the field Devm et aJ. (1 987) offers a more exhaustive list.
Many VOCs exhibit extreme mobilrties, particulaily in the vapor
phase, where their gas diffusion coefficients can be four times
greater than their liquid drffusion coefficients. The vapor phase
migration is influenced by the moisture content of the soil which
altars the air-filled to water-filled pore volume ratio. The reten-
tion of VOCs by sod is largely controlled by reactions with the
solid phase. This retention is especially true for the finer
particles of silts and days The fine-grained particles (. mm)
have a large surface-to-volume ratio, a large number of reactive
sites, and high sorption capacities (Richardson and Epstein,
1971; Boucher and Lee, 1972, L.otse et aL, 1968). Some
investigators athibute the greater sorption of VOCs onto fine-
grained particles to the greater organic carbon content of
smaller particles (Karickhoff at aJ., 1979).
Soil-moisture content affects the relative contnbudons of min-
eral and organic soil fractions to the retention of VOCs (Smith
at aJ. . 1990) Mineral day surfaces Largely control sorption when
soil moisture is extremely low (<1%), and organic carbon
(Conbnued on page 7)
TABLE 2. FACTORS AFFEC1tNG VOC CONC94TRATIONS l SOILS
Fader
Common
Ab&.
Unite
Eflects on VOC Con ratIons i So
flM.. ,..
VOC Chen cat Prop.rU.e
So l ty
C,
mg/i.
Affects fate arid transport m wa , efte
wate a%p , fiuences o thn pa
Roy arid Gil i (1985)
Heniys Constant
K
(atimm )mde
Constant of proponiona ty bmween the water a
pf n aI ,ns; tenVec se Mid presase depondart
Shin ind Sewal (19 )
Spenca . (1988)
Vapor prassiae
v.p.
rim Hg
AI rate of k,es from soi.
Shin wid Sewal (1 9 )
Organic carbon pall. e&
K ,
mg VOCI 9 C
AdaorpLn coef&ient noni r sc ix
Fwnw’ t (1980)
OdenoL water part. eff.
K,,
n VOC/
mg o
E iitimr r m for Wt on of VOC t in w r
aid in orgar (odenol) pfl e. Giiiies atinitI of
w organic frwton of L
Voi Wehir (1983)
.
Bofng pou
b.p.
C C
Aib -evaporabon of VOC aid water from aol aw .
Voi id Wilier (1983)
SoiL’water i str on
coethoent
Kd
[ 11
Ec aberi ainsiaru for b on of airta 1 betuwen
d arid U id phise&
Vo end Wilier (1983)
(Conthiueo9
PHASE
3
-------
TABLE 2. (CONTVIUED)
o n
Fsclor . OIS On VOC Co .i Mi i Ii Sal
Sal Q u uq4rOu
EC meqtl Dog the rwlet Of neg y dwged s s on si
— wf ere dwped VOC may soib; pH de 1 Jert
bi ronsor n pH -1c W] rfiuensos a rar er of sod pro ft
( vtty) nonneu orgerec p UUur 9 ; CftOatS CEC end
r4n4 ty of some VOCs
Tood OI9W1C sobon ‘d8flt •TOC tT C d J’l fl O( 1t P6ItoOflIIJQ me6tin b non-pdar hy&ophob 1 c Cha u at ai. (1988)
( Pu K , ) VOCs; sorpoon Of VOCe ii V ma cun may be Feniw at ai. (1980)
I .• , re .
Sal Phy uperUe .
P 1 e we or sextire A % and, AI sif babon, poiiatr l , r rthon , sotpbon, end F ofw n and
oft, day m ty of VOC6. flJeflsos hydraui as wod as es - Epstein (1971)
eree-to . &rne ratio (s.&.cKd)
s a. m 1 /g Me e soption of VOCe from v or pI se; aI soil Ke fl 61 aJ. (1979)
rosdy end her te r propa es
&ik der ty p g L ed r e una g mob dy and retention of VOCa ‘n sods, encer at aJ. (1988)
w odtuenso sod sanUmg deviso seIe on
Porosity n Void vkmne to total ‘ di.sne r o. Masts vofluiie, Femeret ai. (1980)
1dLdburi, ivt i , and rmgraflon of VOCs &n sod .vsds Shan end Se fI (19 )
Peros i mo6tnse 0 % (w/w) A1$e hy*aniuc sondu vnty of sod and sorpbon of VOCs. Fexner at af (1980)
Def imt s the daso& n and mobibty of VOCs v sod Ctnmu w SP (1985)
Water pstar nai p F m Relates to the rate, n ildy, and anoeratation of VOCs
rw ror nidd w n l a.
HØailic ron cMy K m d Masts .isson ow of VOCs rn sod water dapen ng on
- degree of satiration, gr 6r , and other physisoi te rs
En*o F. s
Re uiidñy RH. vend Stu .ç (1985)
ConM d the imyemer , and of
Ten eran.we T cc VOCe; i*e. ,lat ,d s; be site speak end depexMnt
___ icon si s 1we u rf a 6fterariiafs
8a UK pre $e irni
- Relevant to speed, nmemerl, and of
VOCe remo d, or dth nng from sirtaso
t ne y, r se, end bid, arid datb on of
attest n ment, th on ra , end
OOAooilribon Of VOCs
4
-------
TABLE 3. CHEMICAL PROPER11ES OF SELECTED VOLATiLE ORGANiC COMPOuplDst
From VI be 19 , .My 1964
• 0 no *. r Qiut i o it
• —I L n ra 20 .
m.w.
Compound (glmo le)
SokLbilrdes
(mg /i. @ 20°C) log K
Vapor P euwe
log K K,; (mm @ 20°C)
Benze e
78
1780
-0.24
270 (@30°)
Broniodichioramethane
164
191
211
0.22
76
Bromotorm
253
7500
3190
2.18
210
50
Bromomethajie
95
(@30°)
6 (@25°)
2-Butarione
72
900
270000
1 34
119
1 50
1250
Carbon disul de
76
2300
1 56
026
76
Carbon tetrachlonde
154
800
1 80
260
Chlorobenzene
113
500
2 04
2.64
094
90
Chloroethaj - ie
65
5740
218
1 40
284
016
9
2 Chloroethytviny1 ether
107
1.54
061
1000
Ch omtcrm
120
8000
Ch oromethane
51
8348
1 46
1 97
012
160
Dibromoch oromet,ane
208
3300
0.78
0 91
162
3800
l,2-Dichlorobenzene
147
100
245
2.24
15 (@105°)
1 3-Dc orobenzene
147
123
2.62
3.38
1
l4-Dichlorobenzene
147
(@25°)
49
3.38
1,1-Dichioroethane
99
(@22°)
5500
3.39
1
1 ,2 .Dichdomethane
99
8690
1 66
1 79
018
180
1,1 -Di oroethene
97
134
1.48
004
61
traris-1,2-Dsch loroethene
97
600
500
1.2-D ichloropropane
113
2700
1 56
2.06
200 (@14°)
l3D ropcopene
110
2700
1.99
42
trans-1.3.-DichIorop -oper ie
111
2800
34 (@25°)
Ethylbenzene
106
152
43 (@25°)
2-Hexanone
100
3500
2.60
3.15
7
Methyfene onde
85
20000
138
2
Methyflscbutylketone
100
17000
140
125
349
Perth roethyiene
166
150
1 34
1.46
0002
6
Styrene
104
300
2.60
2.60
0.85
14
11,22 .Tetr hloroethape
168
2.61
2.95
5
Teoroethene
166
2.07
2.60
5
Toluene
92
515
2.78
340
18 (@25°)
1,1,1 -Tnchloroethane
133
2.18
2.69
027
22
1,1 ,2-Tnchloroethane
133
4500
2.19
2.50
1 48
100
Tndlloroethyfene
132
700
2.14
2.07
19
Tnfiuoromethane
137
2.09
2.29
0.37
60
Vin y f acetate
Vinyf cthionde
86
63
(@25°)
25000
1100 (@25°)
2.68
1.59
2.60
0.73
687
115 (@25°)
-
Total xy lenes
106
196
1.38
97.0
2660 (@25°)
5
-------
Various sormaobeS
tev’a-, U ,-, di-, arid m-Chlorophenol (KobayasSu and RstUiiar i, 1982)
2,6-, 2,3Oid orobenzene. 2,4- and 2, tilorobenzene, CO 2
(Kobayash and R n, 1982)
Redu ive dehafogenation under anoxc ndeons, (I e , < 0.35 V)
(Xobayastv and Rittinan, 1982)
Fungi
Pset.ó merias sp
Ac inetoba efsp
Mrry ijc sp
Acetate-grown biofitm
Anaerobic Redu ive dehalogenaflcn to mth ene,d oroethene, arid
— d ’ onde, and finally CO 2 (Vogel and McCaily, 1985)
An robc aloger on to I ,2 .dithforoethene and not 1,1 -dic omethene
(lGeop retal,1985)
Aerobic *wai ed to CO 2 in the presenro of a mutsa of natsal gas
and air
o b ic Various particle breakdown products rrvneraDzed by other
morgan i (Lechevaiier and Led aJier, 1976)
Conlilete nineraiization in 10-14 days (JoN sen, 1976)
Oi’garusms were cepable of sustaining growth in these compounds
with 100%bodegradatlon (Jamison olaf., 1975)
TABLE 4. MICROBiOLOGICAL FACTORS AFFECTING VOC IN SOIL SYSTEMS
Compoun s) CoMtlons
Pentath ropher i ol Aerobic
12,3- and 1 2,4-Tnchlocobenzene Aerobic
Vanous soil bactena
Anaerobic
Tnth roethane, tnchbromelhar ie,
meth 1c onde, th i ’oethane,
dlthloroeihane. vin lxliene th nde,
U, UoWethene, oroethene.
meth 1ene thknde,
Various soil miaobes TeU doroe1hene
Various so miaobes ‘ C-4abe4ed U,chloroethene
Various sod b ena Tnd ,broethene
Adinon ycetes chionnated and non-d ,k,nnated
Aerobic
Aerobic
DDT
kom
Chkmnaled afiphalics
Ci-donnated and nonchbnnated
aromatics
Aerobic
Methanogenic
Aerobic
Methanogenic
Aerobic
Blue-green algae Oil wastes
(cyariobactena)
No bodegr on deser wd (Boirwer, 1984)
Nearly 100% biodegradation obsemed (Boirwer. 1984)
Nearly 100% biodegradation (Boijwer, 1984)
No biodegr on observed (Bot er, 1984)
BiodegradaUon of automobile oil wastes, ank se oil, etc
(Cameron, 1963)
6
-------
partitioning is favored when moisture content is higher (Chiou
and Shoup. 1985).
Biological factors affecting VOC retention in soil systems can be
divided into microbiological and macrobiological factors. On the
microbiological level, the indigenous microbial populations
present in soil systems can alter VOC concentrations. Although
plants and animals metabolize a diversity of chemicals, the
ac1ivitie of the higher organisms are often minor compared to
the transformations affected by heterotrophic bactena and fungi
residing in the same habitat. The interactions between environ-
mental factors, such as dissolved oxygen, oxidation-reduction
potential (Eh), temperature, pH, availability of other compounds,
salinity, particulate matter, and competing organisms, often
control biodegradation The physical and chemical charactens-
tics of the VOC, such as solubility, volatility, hydrophobicity, and
K . also influence the ability of the compound to biodegrade.
Table 4 illustrates some examples of the microbiological alter-
ations of some commonly encountered soil VOCs. In general,
the halogenated alkanes arid alkenes are metabolized by soil
microbes under anaerobic conditions (Kobayashi and Rrttman,
1982, Bouwer, 1984), whereas the halogenated aromatJcs are
metabolized underaerobicconditions To avoid biodegradation
and oxidation of VOCs in soils, scientists at the U.S. EPA Robert
S. Kerr Environmental Research Laboratory in Ada, OK, extrude
the sample in a glove box.
On a macro scale, biological factors can influence the migration
of VOCs in the saturated, vadose, and surface zones (Table 5).
BiollIms may accumulate in the saturated zone and may biode-
grade and bioaccumulate VOCs from the ground water. The
biofilm. depending on its thidcness, r iay impede ground-water
flow Plant roots have a complex mucrofiora associated with
TABLE 5. MACROBIOLOQCAL FACTORS A ECTPIG VOCs
(P4 S L SYSTEMS
,-.
Zone
-1-
B filrr
Sat rated
Biode alation, bio jn4ation,
more or less c a, parent
— , thsk frioã n y
rete sat:ated few
Plant roi
CapBary fringe
vatose
fi.m moy bode ade
or bsoa aniia VOC. root
d rele may sane as
ler VOCm
Animal bwmws
holes
Vadose
May as aliy pail for aid
n onofsafwe
aid sane as mn&utler
.VWWd VOC nbg n
Vegeteti ve
So s
Save as bamer tI fvwi
from aid reted
inMr kAI of ast spas
them known as mycorrhizae. The mycorlThzae may enhance
VOC retention in the soil by biodegradation or oaccumulation
The root channels may act as condurte for increasing the
migration of VOCs through the soil. Similarly, animal burrows
and holes may serve as paths of least resistance for the
movement of VOCs through soil. These holes may range from
capillary-size openings, created by worms and nematodes, to
large-diameter tunnels excavated by burrowing animals. These
openings may increase the depth to which surface spills pen-
etrate the soil. A surface covenng consisting of assorted vegeta-
tion is a signrficant barrier to volatilization of VOCs into the
atmosphere. Some ground-water and vadose-zone models
(e g., RUSTIC) undude subroutines to account for a vegetative
cover (Dean et aL, 1989).
SOIL SAMPUNG AND ANALYSIS DESIGN
Pnor to any sampling effort, the RPM or OSC must es blush the
intended purpose of the remedial invesbganonJfeasi lrty study
(RVFS) The goals of collecting samples for VOA may uridude
source identification, spill delineation, fate and transport, nsk
assessment, enforcement, remediat,on, or post-rernedlation
confirmation. The intended purpose of the sampl i n g effortdnves
the selection of the appcopnate sampling approach and the
devices to be used in the investigation.
The phase part itioning of the VOC can also inNuence which
sampling device should be employed. Computer models gener-
ally are used only at the final stages of a RVFS. However,
modeling techniques can be used throughout the RL/FS process
to assLst in samplmg device selection by estimating the phase
parimoning of VOCs. The RPM is the primasy data userfor a AL’
FS led by a federal agency. As such, the RPM must se4e the
sampling methodology to be employed at the site. Figure 2
illustrates the sequence of events used to plan aVOC sarr ltng
and analysis activity.
The domains of Interest also must be determIned. The target
domains may indude surface (two dimensions) or subsurface
(three dimensions) enwonments, hot apota, a concentration
greater or less than as, on lImit, or the area above a lealong
underground storage tank. Statistics that may be generated
from the target domái date must be considered before a
sample and analysis desigo Is developed. Poesdle statistics of
interest may undude average_analyte concentration and the
variance about the mean ( statistics that coni ie whether the
observed level is signrficsntiy above or below an ellen level) as
wed as temporal and sp l4al trends Data must be of sulfioentiy
high quality to meet the goals of the seniØnq elMty. The level
of date quality is defined by the date quality ob4e vee (DOOs).
In RVFS vTtls$, sites are so Jffo nt and Information on
overall measurement error (samplIng plus analydoal error) Is so
limited that It Is not practical to set universal or generic precelon,
uracy, representathieness, completeness, arid comparabil-
ity (PARCC) goals The reeder Is referred to a use e grthde on
quality assurance In aoü samping (Barth at aL, 1989) aid a
gu ance doaiment for the development of data qua ty ob eo-
fives for remedial response activities (US. EPA, 1987).
000s are qualitative arid quantitabve mente of the level of
uncertainty a decision malcer is wi ng to pl in malW’.g
decisions on the basis of environmental date. ft Is liT oita1t to
realize that if the error ciatad with the sample coI on or
7
-------
“ Confidence
level
• Bias
• Preasion
• Action level
• Analyte level
DESIGN
CHARACTERIZE
SITE
• History
• Process
• Soil properties
• Soil conditions
• E dsting data
• Environmentai
factors
I
SE LE C.T
TOOLS.
• Spilt spoon
• Piston samplers
• Zero contam.
sampler
• Shelby tube
• Veihrneyer tube
• Shovels
*
DRAFT
S&A PLAN
.
.
•
S
S
.
S
S
S
Tools
AnalyncaJ methods
Holding times
No. of samples
Sample mass
Decontamination
QNQC
Field analysis
Handling
Random]
systematic design
Figure 2. Flowchart for planning arid implementation of a sod sampling and analysis activity
DEFINE-
GOAL
• Soil population
• Location
• cs
•Trend
• x, Std. dev.
• Comparison
• Purpose
• Enforcement
• Remediation
• Source ID
+
ANALYTE
OFINTERESr
SELECT
METHODS
SET
000s
-
• GC/MS
•GC
• FieldGC
• Methanol
extraction
I
NO
MINIMIZE: RESOURCES: MAXIMIZE: INFORMATION MAXIMIZE QUALITY
FEASIBLE:
V
YES
V
• Personnel
• Budget
• Time
• Politics
I:
ON•SITE_DATA _____
• Field analysis
• Visual
observations
•Odors
• Population
esibdrty
FIELD.
IMPLEMENTATION
DATA EVALUATION
+
I
OBJECTIVE:
MET
NO
8
-------
preparation step is large then the best laboratory quality
assurance prOgraJll will be inadequate (van Ee et aL, 1990).
The greatest emphasis should be placed on the phase that
contributes the largest component of error. For the analysis of
soils for VOCs, the greatest sources of error are the sample
collection and handling phases.
The minimum confidence level (CL) required to make a
decision from the data is defined by the OQOs. The minimum
CL depends on the precision and accuracy in sampling and
analysts and on the relative analyte concentration. Relative
error may be reduced by increasing either the number or the
mass of the samples to be analyzed. For instance, although
5-g aliquots collected in the field might exhibit unacceptable
errors, 1 00-g samples will yield smaller errors and might
therefore meet study or project requirements. Corn positing soil
samples in methanol in the field also can reduce variance by
attenuating short-range spatiai vanability.
Field sampling personnel should coordinate with laboratory
analysts to ensure that samples of a size appropnate to the
anal yt icai method are collected. For example, lithe laboratory
procedure for preparing aiiquots calls for removing a 5-9
aiiquot from a 1 25-mL wide-mouth jar, as per SW-846, Method
8240 (U.S EPA I 986b), then collecting a larger sample in the
field will not reduce total measurement error, because addi-
tional errors will be contributed from opening the container in
the laboratory and from subsequent homogenization.
Aiiquoting ofa5-g samplein thefield intoa40-rnL VOAvial that
can be directly attached to the laboratory purge-and-trap unit
signrficantly reduces loss of VOCs from the sample (U.S. EPA.
1991a). Significant losses of VOCs were observed when
samples were homogenized as per Method 8240 speafica-
tions. Smaller losses were observed for smaller aliquots (1 to
5g) placed in 40-mL VOA vials that had modified caps that
allowed direct attachment to the purge-and-trap device. The
procedure of collecting an aliquot in the field eliminates the
need for sample preparation and eliminates subsequent VOC
loss in the laboratory
Field-screening procedures are gaining recognition as an
effective means of locating sampling locations and obtaining
real-time data. The benefits of soil field-screening procedures
are’ (1) near real-time data to guide sampling activities, (2)
concentration of Contract Laboratory Program (CLP) sample
collection in crTtIcaJ areas, (3) reduced need fora second v sst
to the site, and (4) reduced analytical load on the laboratory.
Umitations of field-screening procedures are: (1) a peon
knowledge of VOCs present at the site is needed to aco.irately
identify the compounds, (2) methodologies and instruments
are in their infancy and procedures for their use are not well
documented arid (3) a more stringent level of quality assur-
ance and quality control (QNQC) must be employed to ensure
accurate and precise measurements. The potential benefits
and limitations associated with soil-screening procedures
must be carefully weighed and compared to the DOOs.
Certain sampling and analytical methods have inherenUimrta-
tions on the type of QNQC thai is applicable. For example,
splitting sod samples in the field would not be appropnate for
VOA due to excessive analyte loss. The higher the minimum
CL needed to make a decision, the more ngorous the QAIOC
protocols must be. As VOC concentrations in the soil sample
approach the action or detection limit, the quantity and Ire-
quency of QA/QC samples must be increased, or the number of
samples must be increased, to ensure that the data quality
obtained is appropriate to satisfy project objectives.
One critical element in VOC analysis is the appropnale use of trip
blanks, if a sample consists of a silty day loam, a hip blank of
washed sand may not be realistic, for such a blank would not
retain VOC cross contaminants in the same way as the sample.
The trip blank soil matrix should have a sorptive capacity
similar to the actual sample. In additIon, high-
concentration and low-concentration samples should be shipped
in separate coolers.
DEViCE SELEC11OI4 CRITERIA
The selection of a sampling device and sampling procedures
requires the consideration of many factors induding the number
of samples to be collected, available funds, soil charactensiics,
site limitations, ability to sample the target domain, whether or not
screening procedures are to be used, the size of sample needed,
and the required precision and accuracy as given in the DOOs.
The number of samples to be collected can greatly affect sam-
pling costs and the time required to complete a site cflaractenza-
lion. If many subsurface samples are needed, it may be possible
to use sod-gas sampling coupled with on-site analysis as an
integrated screening technique to reduce the area of interest and
thus the number of samples needed. Such a sampling approach
may be appli le for cases of near-surface centamlietion.
Ultimately, the sampling, sample handling, containertong, and
transpoit of the sod sample should minimize losses of volatiles
and should avoid contamination of the sample. Soil sampling
equipment should be readily decontaminated in the field if it is to
be reused on the job site. Decontamination of sampling equ-
ment may require the use of decontamination pads that have
impervious liners, wash and rinse troughs, and careful harding
of large equipment Whenever possible, a liner should be used
inslde the sampling device to reduce potential cross coritamina-
hon and carryover. Decontamination procedures take time,
require extra equipment, and ultimately increase site character-
ization costs. Ease and cost of decontamination are thus unpor-
tent factors to be considered in device selection.
Several soil-screening procedures are In use that indude
he r4epaoe analysis of soils using organic vapor analyzers: w r
(or NaCI-satiJrated water) extraction of soil, followed by static
head pene analysis using an organic vapor analyzer (OVA) or
gas thromatograph (GC); cclodmetrfc test 1db; methanol exti
hon followed by he cpar* analysis or direct injection Into a GC;
and sod-gas sampling (U.S. EPA. 1988). FIeld measurements
may nat provide absolute values but often may be a superior
means olobtairüng relative values. Thee. proosduree are gain-
ing acceptenos.
Sit. CharacWlatlcs
The remoteness of a site and the physical setting may restrict
access and, therefore, affect equipment sele on. Such f rs
as vegetation, steep slopes, rugged or rocicy ten’aln, overhead
power lines or other overhead restrictions, and l of roads can
conb ute to esa problems.
The presence of underground utilities, pipes, electrical lines,
tanks and leech fields can also affect selection of sampling
9
-------
equipment. tf the location or absence of these hazards cannot
be established, it is desirable to conduct a nonirmusive survey
of the area and select a sampling approach that minimizes
hazards. For example, hand toots and a baclthoe are more
practicaJ under such arcumstances than a Large, hollow-stem
auger. The selection of a Sampling device may be influenced by
other contaminants of interest such as pesticides, metals,
semivolatiie organic compounds, radionudides, and explo-
sives. Where the site history indcaies that the matiix is other
than soil, special consideration should be given to device
se4e on. Concrete, reinforcement bars, scrap metaJ, and lum-
ber will affect sampling device selection. Under some circum-
stances, it may not be practical to collect deep soil samples The
presence of ordnance, drums, concrete, voids, pyrophonc ma-
tenals, and high-hazard radioactive materials may predude
some sampling and may require development of alternate
sampling designs, or even reconsideration of project objectives.
SoIl Characte,laijcs
The charactenst,cs of the soul matenai being sampled have a
marked effect upon the selection of a sampling device. An
investigator must evaluate soil characteristics, the type of VOC,
and the depth at which a sample is to be collected before
selection of a proper sampling device. Specific characteristics
that must be considered are
1 Is the sod compacted, rocky, or rubble filled? If the answer
is yes, then either hollow stem augers or pit sampling must
be used.
2. Is the soil fine grained” If yes, use split spoons, Shelby
tubes, liners, or hollow stem augers.
3. Arethereflowungsandsor ter . soil If yes, use
samplers such as piston samplers that can retain these
materials.
SOIL-GAS MEASUREMENTS
SoiL-gas measurements can serve a vanety of screening pur-
poses in soil sampling and analysis programs, from initial site
reconriaissa,i to remediaj monitoring efforts. Soil-gas mea-
suremerits should be used for screening purposes only, and not
for definItive determination of soil-bound VOCs. Field analysis
is usually by hand-held detectors, portable GC or GC/MS,
infrared detectors, ion mobility spe meters (IMS), industha]
hygiene detector tubes, and, recerilty, fiber optic sensors
At some sites, soul-gas sampling may be the only means of
apouinng data on the presence or absence of VOCs in the soil.
For example, when the size and density of rocks and cobbles
at a site prevent insertion and withdrawal of the coring device
and prevent sampling with shovels and U ’owels, unacceptable
losses of VOCs would o ur. Soil-gas measurements, which
can be made on site or with collected soil samples, can be used
to identify volatile contaminants and to determine relative
magnitudes of concentration. Smith et aJ. (1990) have shown
a disparity in soil-gas VOC concentrations and the concentra-
tion of VOCs found on the solid phase.
Soil-gas measurements have several applications. These in-
dude in situ soul-gas surveying, measurement of headspace
conoarllrations above containerized soul samples, and scan-
ning of soul contained in cores collected from drfferent depths.
These applications are summarized in Table 6. Currently, no
TABLE 6. APPliCATiONS OF SOIL-GAS MEASUREMENT TECHPIQUES IN SOIL SAMPliNG FOR VOCs
Aon
Uses
Methods
B ta4 ore
Soul vapou’
Identify sowcos.and extent
Aotve from soul
surve nng
of contanunation. Distinguish
between soul and ground Water
contamination. Detect VOCs
Lmder asphalt, concrete. etc.
probes
into canisters, glass bofbs, gas
sarr iUng bags. Passive sampling
onto buried LsorTXne stt ates.
Folewed by GC o other analysis.
BENEFITS Rapid, inexpensive screemang of
Large areas, avoid san ftng ulbcontaminated areas.
UMfl ’AllONS: False positives and negatves, miss
detedrig bcallzed si.idaoo sp ls, dsequdibnum
between adsorbed arid vapor phase VOC
con
Soil headspa
Screen large ntmters of soul
Measure headspace above
measurements
samples
containerized sod sample
Containers range from plastic
sanawudi bags to VOA vials
Use GC, vapor detectors, IMS, etc
BENEFITS Mou-e repmsen ve of adsorbed sold
phase concant’aion
UMITAT1ONS Losses of vapor phase component
duiing san ing and sample transfer
Screening
Soil cores scanned to Locale
Collect core
soul cores depth where highest VOC
levels are located
(e.g ,
split spoon) and scan ion vapors new
core surface tsing portable vapor
monitor
BENEFITS: Locate arid collect sod from hot spot
in core for word case,
UMrTAT)ONS False negatives and positives,
environmental conditions can influence readings
(a g , wind speed and thedion, terepereture, humidity)
10
-------
star ard protocols exist for soil-gas analysis; many investiga-
tars have devised their own techniques, which have varying
degrees of efficacy Independently, the American Society for
Testing and Matenais (ASIM) and EPA EMSL-LV are preparing
guidance documents for soil-gas measurement. These docu-
ments should be available late in 1991
The required precision and accuracy of site characterization, as
defin d in the DOOs, affect the selection of a sampling device.
Where maximum precision and accuracy are required, sampling
devices that collect art intact core should be used, particularly for
more volatile VOCs in nonretentive matrices Augers and other
devices that collect highly disturbed samples and expose the
samples to the atmosphere can be used if lower precision and
accuracy cart be tolerated. Collection of a larger number of
samples to characienze a given area, however, ca_n compen-
sate for a less precise sa_mpling approach The doser the
expected contaminant level is to the action or detection limit, the
more efficient the sampling device should be for obtaining an
accurate measurement
SOIL SAMPLING DEVICES
Table 7 lists selection critena for different types of commercially
available soil sampling devices based on soil type, moisture
status, and power requirements The sampling device needed
to achieve a certain sampling and analysis goal can be located
in Table 7 arid the supplier of such a device ca_n be identified in
Table 8. Table 8 is a partial list of commercially available soil
sampling devices that are currently in use for sampling soils for
VOC analysis. The list is by no means exhaustive and indusion
(Conbriued co page 14)
TABLE 7. CRITERIA FOR SELECTING SOIL SAMPUNG EQUIPUENTt
Type of Sampler
Obtains
Core
Samples
Most
Sut ls
SoIl types
Operation
In Stony
So I ls
il le Sod
Mo lsbzs
Con t Ioos
Refatlys
Ses%ple
S
Labor
J em.nds
(#o(Per.oos)
m 1
or Pow
Operation
A Mechanical San le Recovery
1 Hand-held Power augers
No
Coh/ h1ess
Unfavorable
trile,mediate
2 Solidstemfllgtnaugers
No
CoW h’ ss
Favorable
Wet to
Large
Pow
3 H w-steni augers
Yes
olVcohless
Favtizilav
Wet to y
Lzge
Pow
4 Budwt augers
No
Cohf h1esa
Favorable
Wetto&y
Large
Power
5 Baclthoes
No
ColVoehiess
Favorable
Wet to y
Large
Large
2.
2+
Power
Power
BSan ers
1 So w-ype augers
No
Coh
Unfavorable
lntorme
Sma
2 Barrelaugers
Srigle
a. Po -hole augers
No
Coli
Unfavorab le
Wet
b Dutch augers
No
Coh
Unfavorable
wet
large
Singe
c Regular barrel augers
No
Coh
Unfavorable
lntacmed
Large
Smgle
Mesu
Sand augers
No
Cohiess
Unfavorable
frtteimed ta
Large
SlnØe
Maiu
e Mud augers
No
Coh
Unfavorable
Wet
large
Single
3 TL e-typO sarr ers
Large
Single
a. Soil sainplet,
Yes
Coh
Unfavorable
W e tto y
Sm l
b Vethmeyer tt es
Yes
Coh
Unfavorable
lritarme
Single
c Shelby tubes
Yes
Coh
Unfavorable
Ir itermecIlate
Large
Single
d RIng-Irted san tlers
Yes
Coliless
Favorable
Wet to nteiine ate
Large
2+
Both
e Co ussarr lers
Yes
Coh
Unfavorab le
etto thy
Large
2i
2+
Beth
Retonsan le rs
Yes
Coh
Unfavorable
Wet
Large
9 Zerocomerrunationsarnplers
Yes
Coli
Unfavorable
Wettov terme
Large
Sm
2+
2+
Both
h SpUtspoonsarrçlers
Yes
Coh
Unfavorable
tiierme i
2+
4 Bu samplers
No
Coh
Favorable
Wettocty
Large
Large
Single
Mwe i
t wdftamUS EP& 1986..
AU fand-opera d neor of sai i . e nwwm saITlerL , be uKed by one poiscit
Coh —
11
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TABLE & EXAMPLES OF COMMERCIALLY AVAiLABLE SOIL SAMPUNG DEViCES
Le th thu)
LD. t s)
.
AkwM1ll d D & P sge and Tr 3 r dy swT! e sods
Uamsta nç Co. Sod San er 0.5 b a ee1 ç by 1.ow Lever
814 ICrVi Henry S’eet S ess eel Pwge and Tr m ho
Aiexz* . VA 314
703 - 549 - 5999
frôar Dr Co. H evy Duty l. 18824 SØt e ows for easy
P.O. Box 830 Spdt T A e Swrçler 1-1P2 4-1 /2 sarT e removal
Suk ,PA Steel
717-586-2061
De. n Core Bairel 24860 Brass WI rsn Lm bsbed
1-7)8 te 6- 1 6 saiTile from cohess’e sods
AMS COreSOdSarr IIeI- 21o12 S ess plastic Goodrit pesofsoiis
He on Oregon Trail 1.1)2 3 aljwn, Ixuize
AmencanFajs ,ID83211 Aboy , afless teflon
Dual Pispose Sal 12,18 824 8ut yata, Teflon Ad s to AMS i s A ,*ii
Recovary Pmbe 3/4 end I eea hwom& 1fte rnent Use
4 l3OAJby ,
Sod Recovery Auger 8 to 12 Pt ic &afless M dle to AMS exteasion
283 Teflon a lisnmum aiidoross-4 andes.
Concord, Inc. Speedy Soil Sarr )ler 488 72 Autor ad sy m alows
007thAve N 3/16to3-1/2 rethevajo 24msod
Far9o,P 58 102 Stauless saiTOeel l2sec.
701 - 0-1260
Zero Cor ai vnatjoi, Llrvt
Han Hed San r
CME 60 Butyi’ate Mayrtbe x ein
Central Mine Equp. Co 2-1/2 to 5-3/8 ony sods. Adapts to CMS
6200 North Broedway Steel, s ess auger.
St Lo as. MO 63147
800-325-8827 Searing Heed Coritriuous 60 ButyTate Versa e system. Adapts
San leTi eSy ern 2-1)2 b o1 augers.
Steel, ass
Diedndi Dnlhng E p Heavy Duty Split 18 £24 Biass, plastic Full line of ssones
P 0 Box 1670 T& Sa ier 2,2-1)2,3 amless, Teflon are avai fe.
Lapoiie, IN 46350 Steel
CoousSarr ler 60 Brass plastic
3,3-1)2 a irUess, Teflon
(Continued)
12
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TABLE 8. (CONI1NUED)
—
— s)
1.0. (fficfles)
Maufactures Sampllflg Dev1 Sampler Matertai’
Unera Feelures
Geoprobe Systems Probe Drive 11-1/4 Remains n eteIyseaied
607 Barney St Soil Sampler 0.96 w1,ile pustied to depth in
Saiina.KS Moy steel sod
913-825-1842
Giddings Maclime Co Conng Tubes 48 & 60 Butyrate A senes of optionaJ 8 in
P 0 Drawer 2024 7/8 to 2-318 slots permi observation of
Fort Collins, CO 80522 4130 M&ycl rome the sample.
303-485-5586 -
JMC Environmentai msts 36848 PETGpL a C,
Clements and Associates Sub-sod Probe Q 9 stainless peneüate the hardest ol soi .
RR. lBox l8G Nickaiplated
Newton, LA 50208
800-247-6630 Zero Contamination 12,18 & 24 PETG p1a c, Adepts top probe.
Tubes 0.9 stainless
Mobee Onhing Co. L mac Split 18 & 24 Brass. Ad Xs to Moble weC. e
3807M s on Ave. Ba!TeI Sampler 1-1i2 plastic
lr ianapolis, IN 46227
800-42 4475
stinc. ZeroCitananatmon 12,18824 Handsarrqjei-goodb ’
66 Aftmretht Drive Sampler 0.9 therical residee stiut e&
Laiw Blufi, IL Chrome plated
800-323-1242
Thin Wall TiEs 30 Wil take ttd isbed sertçlee
Sampler (Shelby) 2-1)2,3, 3-1t2 in ixiheens ee amid days.
: ‘
S t Ti S ipler 24 Forced i by
1 —1/2to3 h * Icprseor wmQ .
Vvtypecfaa. 1 I..
Ve8veyerSoi 48872
S ingT i Ee 3/4 u, dcr a*.
Spragmk&Hen dtnc. S&H *8ai el 18824 Agenera çurp
Scranton, PA 18501 Sw ip ler 2to3-1/2 s&1 da ced sq d
600-344-8506 ___
heunled.
Not: e i eriam . U on in ioiid n be x eeusd ii wmu ins.
13
-------
in the list should not be construed as an endorsement f r their
use.
Commonly, soil samples are obtained from the near surface
using shovels, scoops trowels, and spatules . These devices
can be used to extract sod samples from trenches and pits
excavated by beck hoes. A predeaned shovel or scoop can be
used to expose fresh soil from the face of the test pit A thin-
walled tibeor smaildameter. hand-held corer can be used to
collect soil from the exposed face. Bulk samplers such as
shovels and trowels cause considerable disturbance of the soil
and expose the sample to the atmosphere, enhanong loss of
VOCs. Seegnst and Jenssen (1990) have shown that sampling
procedures that cause the least amount of disturbance provide
the greatest VOC recoveries. Therefore, sampling devices that
obtain urdstirbed soil samples using either hand-held or me-
thanicai devices are recommended. Sampling devices that
collect un bed saroples include spilt-spoon sai ers, rIng
— continuous samplers, n Inabon san ers,
sf4 Shelby ties These sampling devices can be used to
collect surface sod samples or they can be used in con jun on
wTth hollow-stem augers to collect enbsurface samples. The soil
sampling devices discussed above are summarized in Table 9.
Devices where the soil samples can be easily and qucidy
removed and centajnenzed with the least amount of disturbance
arid exposure to the atmosphere are highly recommended. U.S.
EPA (19868) gives a more detailed discussion on the proper use
of drill rigs and sampling devices.
Liners are available for many of the devices listed in Table 9.
Liners make sell removaJ from the coring device much easier
and quicker. Liners reduce cross contamination between
samples and the need for decontamination of the sampling
device. The liner can run the entire length of the core or can be
precut into sections of desired length.
When sampling for VOCs, it is othcal to avoid interactions
between the sample arid the liner and between the sample and
the sampler. Such interactions may include either adsorption of
VOCs from the sample or release of VOCs to the sample.
Giliman and O’Hannesin (1990) studied the sorption of six
monoaromatic hydrocarbons in ground water samples by seven
matenais. The hydrocarbons included benzene, toluene,
ethylbenzene, and 0-, m-, and p-xylene. The materials exam-
ined were stainless steel, rigid PVC, flexible PVC, Pi P- Teflon,
polyvinyl idene fluoride, fiberglass, and polyethylene. Stainless
TABLE 9. $01 SAMPLERS FOR VOC ANALYStS
mminded
Not l ccnwnended
Split oon wilners
SoMd it ners
Shaby tbe (thu wall tiles).
Dc mg mud auger
Hofow ern augers
Air drilu ig auger
V&wneyer King tiles
Cable tool
wliners
Hand augers
P ton sanplers’
Bw augers
Zero nvnation
Scoop mplers
Probe -i*ive sanplers
Excavalmg tools, e.g , thovels, baddioes
steel sh ri,d riO s gnhtkarTt sorption slng an 8-week period. Au
polymer rnatenais sorbed all compounds to some extent The
order of sorption was as_follows: rigid PVC fiberglass .c
polyvinylidene fluonde < t ’ I t- c polyethylene <1lex le PVC.
Stainless steel or brass liners should be used since they exhibit
the least adsorption of VOCs. Other materials such as PVC or
acetate may be used, provided that contact time between the
soil and the liner material is kept to a minimum. Stainless steel
and brass liners have been sealed with plastic caps or paraffin
before shipment to the laboratory for sectioning and analysis.
VOC loss can result from permeation through the plastic or
paraffin and volatilization through leaks in the seal. Acetate
liners are available, but samples should not be held in these
liners for any extended period, due to orpbon onto and
permeation through the material. Altem vety, the soil can be
extruded from the liner, and a portion can be placed into a wide-
mouth glass jar. Smaller aiiquots can be taken from the center
of the precut liner using subconng devices and the soil plug
extruded into VOA vials.
TRANSFER OF SOIL SAMPLES FROM DEViCE TO
CONTAINER
The sample transfer step is perhaps the most cnticai and least
understood step in the sampling and analysis procedure. The
key point in sample transfer, whether in the field or in the
laboratory, isto mirumize disturbance and the amount of time the
sample is exposed to the atmosphere. it is more important to
transfer the sample rapidly to the container than to aoi .irate4y
weigh the aiiquot which is transferred, or to spend considerable
tine reducing headspace. Therefore, a combination of a device
for obtaimng the appropriate mass of sample and placement of
the aliquot into a container that can be directly connected to the
analytical device in the laboratory is recommended. Severai
designs are available for obtaining a S-g aliquot (or other size).
Most subconng devices consist of a plunger/barrel design with
an open end. The device shown in Figure 3 was constructed by
Associated Design & Manufactunng Company (Alexandria,
VA). Other designs include synnges with the tips removed, and
cork borers (Table 8). The device is inserted Into the sample and
an aJiquot is withdrawn. The aliquot, which is of a known volume
and approximate weight, can then be extruded into a tared 40-
mL VOA vIal. Routinely, the vial is then sealed with a Teflon-Imed
septum cap. Teflon, however, may be permeable to VOCs.
Auuminum-lined caps are available to reduce losses due to
permeation. At the Laboratory, the vial must be opened and the
contents of the vial must be transferred to a eparger tube. The
transfer procedure will result in significant losses of VOCs from
the head pace in the vial. The modified purge-and-trap cap
shown in Figure 4 eliminates the loss of VOCs due to container
opening and sample transfer. The soil is extruded from the
subcorer into a tared 40-mL VOA vial and the modified cap is
attached inthefleld. In thelaboratory, the vialisattacheddirecdy
to a purge-and-trap device without ever being opened to the
ambient air.
Use of subcoring devices should produce analytical results of
increased acouracy. In order to test this hypothesis, an expen-
merit was conducted in which a bulk soil sample was spiked with
800 ig/lcg of different VOCs (Maskannec, 1990). Three aliquats
were withdrawn by scooping, and three ahquats were withdrawn
by using the sub-corer approach. The results are presented in
Table 10. Although neither method produced quantitative recov-
ery, the subcorer approach produced results that were generally
14
-------
Method
sof
%
S n
.q
Compound
Method
Method”
of iI
C ethane
50
1 5
6
153
Oromomethane
31
536
4
67
Chloroethane
78
946
10
118
11-DKt oroethene
82
655
10
82
11 -Dichloroethajie
171
739
21
82
Chbrobrn
158
534
20
67
Carbon tmrathonde
125
658
16
82
12Dichiorop r opar
147
766
18
98
Inroethene
120
512
15
64
Benzene
170
536
21
80
11,2-TndIom e t haj,
78
477
10
60
Bromotorn
30
170
4
21
1,1 ,2,2-Trthomethnjie
46
271
6
34
Toluene
129
656
16
82
—
Ethy eruene
57
298
7
37
68
332
8
42
Stymne
30
191
4
24
Noir meeEd c i sanple v a. mr
method i e d sWm F se 3. S m eçè.d th 800
4cg ci e fl VOC
five times higher than the standard approach, whereby the
contents of a 1 25-mL wide-mouV, jar are poured into an alum -
num tray and homogeruzed with a s iniess steel spatula A 5-
g sample is then placed in the sparger tube (SW-846, Method
8240). Several compounds presented problems with both
approaches: styrene potymenzes, blomoform purges poorly,
and 1,1 ,2,2-tefr chloroethacie degrades qulctdy.
lIT’ Stalnleee
Steel Body
O - Rlng
1116”
Teflon Ball
Receiving union from
Purge .and-T ap Device
112” Stalnlesa
St Body
0-Ring
Hoia Cap
40 ml Vial
Pu eNee e
Fçure 4. ModIfied purge-and- 40-niL VOA
conta nenzing samples m the field. Vl
at thed dIrectly to a pwge-and-tr , system
without exposure of sample to the a nosphece.
Figure 3 Small-diameter hand-held subconng device made
by Assocated Design & Manufactunng Company
(Aiexandna, VA).
TABLE 10. LABORATOHY COMPARISON OF STANDARD METHOD
AND SUBCORER METHOD
15
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1r1 IOth stidy (U.S. EPA. 1991a). a large quantity of well
characterized soil was spiked with 33 VOCS and was hornog-
enized. From the homOgem2 d mat0 , a 5-g aiiquot of soil was
placed in a 40-mL VOA viai and sealed with a modified purge-
and-trap cap (Figure 4). The remaining soil was placed in 125-
mL wide-mouth jars. The samples were shipped via air camer
and were analyzed by GC/MS with heated purge and trap. The
40-mL VOA vials were connected directly to a Tekmar purge-
and-trap uni! without exposure to the atmosphere The wide-
mouth jars were processed as per SW-846 Method 8240 spec-
fications (U.S. EPA, 1986b). Table 11 compares the resutts of
the GC/MS analyses using the two pretreatment techniques
The modified method (40-mL VOA vial with a modified cap)
yielded consistently higher VOC concentrations than the trath-
lionel Method 8240 procedure (U.S. EPA, 1986b).
The standard methods for VOC analysis, SW-846, Method 8240
and Test Method 624 (U.S. EPA, 1986b; U.S. EPA, 1982), call
for the containerizing of soil samples in 40-mL VOA vials or 125-
mL wide-mouth jars with minimal h sae 1 cp . As previously
desa bed, wide-mouth jars may not be the most appropeate
containers due to sample aliquoting requirements. Although
wide-mouth jars may be equally as effective as 40-niL VOA vials
in maintaining the VOC content of soil samples, the sample
preparation procedure that is required with jar-held samples
causes significant (>80%) loss of highly volatile VOCs (Siegrist
and Jenrisen, 1990). However, if samples are collected in such
containers, it is important to ensure sample integrity, preferably
by using amber glass jars (for photosensitive compounds) with
solid phenolic resin caps and foam-backed Teflon liners. Alum i-
num-lined caps are not available for the wide-mouth jars. Soil
shouldbewipedfromthethreadsof the jartoensureat ightsea l.
The methanol-immersion procedure calls for the transfer of the
sample into a glass jar conteining a known volume of chrornato-
graphic-grade methanol (usually 100 niL) or in a 1:1 weight-to-
volume ratio of soil to methanol. This has the effect of preserving
the volatile components of the sample at the time the sample us
placed in the container. Furthermore, surrogate compounds can
be added at this lime in order to identify possible changes in the
sample dunng transport and storage. The addition of methanol
to the sample raises the detection limi from 5 to 10 rg(Kg to 100
to 500 Mg/kg, because of the attendant dilolion. However, the
resulting data have been shown to be more representative of the
original VOC content of the soil (Siegrist and Jennsen, 1990,
Siegnst, 1990). In a companson of transfer techniques, Siegnst
and Jennsen (1990) demonstrated thai minimum losses were
obtained by using an undisturbed sample followed by immediate
TABLE 11. COMPARiSON OF VOC CONCENTRATIONS 4 SPIKED SOIL ANALY D BY METHOD 8240 AI UO RED METHOD 8240
thod
—Concun atlon g)
‘ 1 o . -d
M ed
VOC 8240t
8240tt Diftaiwice
—Cancen on g)
Moifted
M ed
VOC 8240t
8240ft Diffaisece
t Metiod 8240 ç 1 -iit rdeuth r iT ig aL inç n9 vi bburaL y 1u9
tf Melhod 8240 usmg 4Oiri vai &ç nç l vi d ie , el ied b ulaLiy pqVrap arely
— ll e e ii y pv r tian 0, rth Pvais 01
cwi e s 1I i y 7ealer tiaii 0, rth P - akie betwien 0.01 and 005
No iiw was 300
i 1c l i lorde
9
3
44
32
35
29”
D8xornodiloromethane
1,l2.Tn oroeffisne
121
142
159
193
38
51
Chloroethane
6
36
30”
ere-1,3-Did1oropropene
154
203
49
Meth 1ened ilonde
69
100
31”
Broiwil c n
116
140
24
Caibon daiflde
32
82
50”
Teuadioroethene
62
124
6Z ’
1.1 - d omethene
12
35
zr
1,122-Tetiadloroidiane
137
162
25
1,1- dloroethane
34
83
49”
Toliene
85
161
76’
12.Didloroet lw ie
36
66
30”
Chk robenzene
91
132
41”
Ch lorotom,
56
96
40”
Ethyberizene
85
135
50”
1,1 ,1-Tn omethane
26
90
54”
Styvane
86
114
28’
Carbon Wonde
18
61
43”
To Jx 1enes
57
85
28”
Vu ’u 1 tate
18
26
8
12 -l dlomeV ’ iane
101
159
58”
KETONES
os-1,3-Dudiloropropene
136
189
53’
A tone
336
497
161’
Tnthbroethene
48
87
39”
2-8u icne
290
365
75
Benzene
Bmmoc dloromethaiie
56
114
58
2-Hexanone
200
215
15
16
-------
immersion into methanol. The results for SIX VOCs are shown in
Figure 5 At high VOC spike levels (mg/kg) the investigators
found that headspace wrthnn the bottle Caused a decrease in the
concontratlon of VOCs in the sample. At lower spike levels,
however headspace did not seem to be a major contributor to
VOC losses (Maskannec, 1990). In another study (U.S EPA.
1991a), soilcore
and placed in a 40-mL VOA vial provided consistently higher
TREATMENT A
UNDISTURBED SOIL
PLAS T1C BAG
LOW HEADSPACE
TREATMENT B
UNDISTURBED SOIL
GLASS JAR
HIGI HEADSPACE
TREATMENT C
DIS11JRBED SOIL
GLASS JAR
LOW KEADSPACE
S
Concentration, ppm
TREATMENT D
UNDISTURBED SOIL
GLASS JAR
LOW HEADSPACE
TREATMENT E
UNDISTURBED SOIL
GLASS JAR
METhANOL
TOLU9 E
— cao oee
Figure 5. VOC recovery as a function of sample treaUnent.
15
10
0
T AT TA T AT ITB T AT ITC T AT P T AT ITE
— METHYLENE CHLORIDE — 1,2-OICItOROETh
conceiihutlOfl, ppm
2.5
2
13
0
T _ATVB(T A T A1 (T THEA1 lT C T A1 lTD T A1 (T E
1,1,1 ,-T LOROEfl1ANE — T *tOROE
17
-------
VOC levels than a sample taken from the same core, placed in
a 1 -mL wide-mouth jar, and later POUTed 0 (11, homogenized,
and a 5-g aiiquot taken from the bulk material as per Method
8240 specifications.
SOIL SAMPUNG SCENARIOS
The foIIowrn rec riendations for soil sampling and sample
handhng are presented for the three generai sampling sce-
nanos described earlier
1. Open Test Pft or Trench
Samples are often collected from exposed test pits or trenches
where remedia on efftxts are in progress Srtes may also be
encountered where large-diameter coring devices cannot be
employed. In such instances, aude sampling devices, such as
trowels, spoons, shovels, spades, scoops, hand ai.igers, or
bucket wagers must be used to excavate the soil.
The exposed f of an excavated test pit is soaped to uncover
fresh material. Samples are collected from the soaped face by
using a small-diameter, hand-held corer (Figure 3). If the
nominal 5-g sample is to be collected, the appropriate volume
(3 to 4 mL) is extruded into a tared 40-mL VOA vial and sealed
with a mothfled purge-and-trap cap (Figure 4). The vial is thlied
to 0° to 4°C and sent to the laboratory where the entire contents
of the vial are purged without opening the vial (U.S. EPA
1991 b) Though this method minimizes losses of VOCs, the
small sample size may exhibit greater short-range spatial
variabdrty than larger samples.
Alternatively, a small-diameter, hand-held sell corer (Figure 3)
can be used to collect a larger volume of soil. The soil is
extruded to fill a 40-niL VOA vial with a Tefion- ined septin, cap
(minimal he 1sper ) , chilled, and sent to the laboratory The
major weakness with this method is that VOCs are lost in the
laboratory dunng sample homogenization, preparation of
aJiquots from a subsample, and the transfer to the extraction or
sparging devx .
if large coarse fragments or highly compacted soils are encoun-
tered, the use of a hand-held corer may not be possible In this
ca_se a’ude sampling devices are used to rapidly collect and fill
(minimal headepace) a 125- or 250-mL wide-mouth glass jar.
The threads are wiped clean and the jar is sealed with a foam-
backed Teflon-lined cap. The jar is chilled immediately to 0° to
4°C for shipment to the laboratory. Losses of VOCs are consid-
erably greater with this method due to demuption of the matrix
and losses in the laboratory during sample preparation. Metha-
nol immersion may be more suitable for these matrices.
2. Surface Solla (.c 5 ft deep)
The preferred soil sampling procedures reduce VOC losses by
minimizing sample disturbance dunng collection and ti’aristerto
a container. The collection of soil cores with direct extrusion into
a container accomplishes this goal. A larger-diameter coring
device (e.g., splrt-spoon sampler, Shelby tube, zero-contami-
nation sampler) is used to collect an intact sample from the
surface soil or from an augered hole. Many of these samplers
can be used with liners, an insert that greatly reduces the time
required to remove the soil and obtain a subsample. For
subsamples collected from split spoons or extruded large-
diameter cores, the section to be subsampled is scraped and
laterally suboored, orthe extruded soil is cut or broken to expose
fresh material atthe depth orzone of interest, then longitudinally
suboored. For large-diameter cores that are collected in precut
liners, the liner sections are separated with a stainless steel
spatula, and a small-diameter hand-held corer is used to collect
a subsample from the center of the liner section. The uppermost
porton of the core should not be sampled, because it is more
likely to be cross contaminated. The small diameter corer
(Figure 3) is pushed into the soil, the outside of the corer is wiped
clean, and the required core volume (typically about 3 to 4 mL
or5 g) is extruded directiy into a tered 40-rnL glass VOA vial and
sealed with a modified purge-and-trap cap (Figure 4) The vial
threads and lip must be free of soil to ensure an airtight seal
3. Subsurface soIls 5 ft deep)
The same sampling pnndples apply for the collection of deeper
soil samples. Collection of soil cores with direct extrusion into a
containergreattyreducesthelossofVOCs. Tube-type samplers
such as split-spoon, Shelby tubes, and zero-contamination
samplers are used inside a hollow-stem auger to obtain an intact
sample from greater depths. The coring device is retrieved and
a subsample is obtained in a similar manner as that descrIbed
for surface soils.
METhANOL IMMERSION PROCEDURE
Soil collected by protocols outhned above can be placed in a
tared wide-mouth glass jar containing pesticide-grade methanol
(1:1 weight-to-volume ratio of soil to methanol). The ‘nmersion
of relatively large soil samples into methanol has the advantage
of extracting a much Larger sample that is probably less prone to
short-range spatial varIability. This is of particular advantage
with coarse-gramed soils, materials from wtiidi it is hard to
obtain a 1 to 5-g subsample for analysis.
Multiple small-diameter corers can be immersed in a single
methanol-filled jar to produce a composite sample
Compositing becomes pr caJ because VOCs are soluble in
methanol, thus reducing losses. Appropriately collected corn-
posrte samples can produce more representative data than a
comparable number of individual samples. Short-range spatial
varrabihty is greatly reduced. Another advantage is the ability to
reanalyze samples. The main disadvantages of using methanol
include the requirements for handling and stupping the media-
nolandthedetectionhmhthatisraisedbyafactorof about 10
to 20. For the methanol-immersion procedure, jars filled with
methanol and shipped to the laboratory are classified as a
hazardous material, flammable liquid and must be labelled as
per Department of Transportation specifications (49 CFR,
1982). If these disadvantages are unacceptable, then the
modified purge-and-trap procedure may be applicable.
9ELD STORAGE
Material containing VOCs should be kept away from the sample
and the sample container. Hand lotion, labeling tape, adhesives,
and ink from waterproof pens contain VOCs that are often
anaiytes of interest in the sample. Samples and storage contain-
ers should be kept away from vehicle and generator exhaust and
other sources of VOCs. Any source of VOCs may cause
contamination that may compromise the resulting data.
18
-------
Once samples are removed from the Sampling device and
placed in the appropriate storage container, the containers
should be placed in the dark at reduced temperatures (00 to
4°C). Excessively cold temperatures (< ‘10°C) should be
avoided: studies have shown greater tosses of analytes due to
reduced pressures in the container, sublimation of water, and
concomitant release of water-soluble VOCs into the headspace
Upop opening the container, the vacuum is quickly replaced with
ambient air, thus purging out VOCs from the headspace
(Maskannec et al , 1988). Extremely cold temperatures can also
loosen the seal on the container cap. Caps should be
retightened after 15 minutes at reduced temperatures. Samples
should be kept in ice chests while in route to the shipment facility
or laboratory At temperatures above freezing, bactenal action
can have a significant impact on the observed soil VOC con-
centration. Numerous preservation techniques are being
evaluated at the University of Nevada Environmental Research
Center in Las Vegas and at Oak Ridge National Laboratory.
SHIPPING
Given the short holding times required for VOC analysis under
Method 8240 (10 days from sample collection to analysis),
samples are usually shipped via air carner to the anaiyticai
laboratory. Samples should be well packed and padded to
prevent breakage Temperatures in cargo holds can increase to
more than 50°C dunng transit, therefore, the need for adequate
cold storage is critical. Styrofoam coolers are commercially
available to accommodate 40-mL and 1 25-mLglass containers.
Sufficient quantities of Blue tce or Freeze Ge1Th packs should
be placed in the container to ensure that samples are cooled for
the duration of the shipment. A maximum-minimum thermom-
eter (non-mercury) should be shipped with the samples. ft
sample containers are not adequately sealed, VOC losses can
occur These losses may be exacerbated by the reduced
atmosphenc pressures encountered in the cargo holds of air
carriers. Figure 6 illustrates the changes in temperature and
pressure in the cargo hold of various air carriers aircraft. Three
major air camers have been monitored and have shown similar
fluctuations in temperature and pressure (Lewis and Parolini,
1991). Lewis et aJ. (1990) noted decreases in VOC concentra-
tions in soil samples that were shipped compared to samples
that were analyzed in the field, If the container is of questionable
or unknown integrity, it should either be evaluated pnor to use or
a previously characterized container should be used.
As discussed previously, samples that are immersed in metha-
not have spectai shipping requirements. These samples must
be shipped as Flammable Liquids’ under Department of Trans-
portation (DOT) requirements, A seoondasy container is re-
quired for shipment of any item dassthed as a flammable liquid.
PRESERVATION
Improvements ie opera1ionai factors such as sampling device
efficiency, sample transfer, containerizing, shipping, storage,
laboratory sample preparation, and analysis will reduce VOC
losses from soils. Two pnncipai matrix-specific factors that can
contnbute to the loss of VOC in soils are b4odegradation and
volatilization. An effective preservation technique should act on
these matrix-specific factors to reduce losses of VOCs.
The required preservation technique for soil samples storage
at 0° to 4°C in the dark. This technique retards biodegradation
C)
0
It,
I
15
14
13
12
11
I v
FEDERAL EXPRESS
‘6 0 5 10 15
15
14
13
12
11
10
—
-
fljc X
V
.8 0 5 10 15 8 8 40
Elapsed Time (hr)
Figure 6. Temperature and pressure fluctu ions recorded in
the cargo hold of venous air carnors. Recording
device was shipped from Las Vegas, NV, to Pearl
River, NY, and returned.
AIRBORNE
6 0 5 10 15 8 35 40
l x
—
—
19
-------
processes mediated by soil microorganIsms. Some micicorgan-
isms, however, such as fungi, are biologicaily active even at
4°C. Woff at al. (1989) investigated several methods (i.e.,
chemical p4 irradiation) for sterilizing soil and concluded that
mer snc chloride is one of the most effective preservatives that
causes minimal changes to the chemical and physical proper-
ties of the soil. Stuartet al.(1 990) utilized mercuric chlonde as an
antimicrobial preservative to stabilize ground-water samples
contaminated with gasoline Other researchers (U.S. EPA
1 991a) have used mercunc chloride to retard biodegradation of
VOCs in soil samples. The soils were spiked with 150 j. i .g/1g of
Target Compound Ust (TCL) VOCs and were preserved with 2.5
mg of mercunc chloride per 5g of soil. The results indicated that
the amount of mercunc chionde needed to reduce biodegrada-
tion was directly related to the soil’s organic carbon content. In
addition, the levels of mercuric chloride added to samples did
not interfere with sample handling or analysis. Currently, re-
search is underway to quantitate the required mercuric chloride
concentration as a fun on of soil organic content.
The loss of VOCs through volatilization is reduced by optimizing
sample handling procedures. When samples require laboratory
pi ’etreatinent. severe losses of VOCs (up to 100%) have been
observed. In order to minimize volatilization losses, several
preservatives have been examined (U S EPA 1991 a), induding
solid adsorbents, arihydrous salts, arid water/methanol extrac-
ben mixtures The most efficient preservatives for reducing
volatilization of VOCs from soils have been two solid
adsorbents, Molecular Sieve - 5A’ (aluminum silicate desic-
cant) and F1orasil’ ’ (magnesium silicate desiccant). The addi-
tion of 0.2 mg per 5 g of soil greatly mci-eased the recovery of
VOCs from spiked samples. The mechanism is believed to
involve the displacement of water from adsorption sites on the
soil particle and bmding of VOCs to these freed sites. Currently,
research is in progress with soils obtained from actual contami-
naled sites.
LABORATORY PROCEDURES
Sample Storage
Most regulatory procedures specify storage of samples for VOA
at 4°C in the dark. Sample coolers should be opened under
chain-of-custody conditions, and the temperature inside the
cooler should be verified and noted. Samples should be trans-
ferred to controlled-temperature (4°C) refrigerators until analy-
sis. In many cases, insufficient cooling is provided during
transport In these cases, data quality may be compromised.
Sample Preparation
The two most commonly used methods that satisfy regulatory
requirements torthe analysis of soil samplesfor VOCs are direct
purge and trap and methanol extraction Each procedure has
benefits and limitations with respect to sample preparation prior
to VOC analysis of soils.
The modified purge-and-trap procedure has the following char-
actenstics
Homogenization of contents of wide-mouth jar will cause
significant VOC losses The collection of a 5-g aliquot in the
field arid placement into a tamed vial sealed with a modified
purge-and-trap cap is recommended.
• Surrogate addition should be made to the soil in the field, if
possible
• May be more susceptible to short-range spatial variability.
• Samples should be brought to ambient temperature before
purging.
• May be more suitable for low-level samples.
The methanol-immersion procedure has the following charac-
teristics.
• The key is to minimize the time samples are exposed to the
atmosphere pnor to immersion into methanol.
• M inimumdetecbonlinirtscanberaisedbyafactorofiOto2O.
• The best option for sample archival because VOCs are highly
soluble in methanol.
• Large-mass samples can be extracted in the field in a 11 ratio
arid the methanol extract shipped to the laboratory for
analysis.
• Can collect composite samples.
The analytical methods that can be used for the analysis of soils
for VOCs are summarized in Table 12. An analytical method
should be selected that is compatible with the recommended
sample collection arid containerizing procedure discussed ear-
her.
CONCLUSIONS AND RECOMMENDATIONS
Current research on sampling soils for VOC analyses answers
many of the questions asked by RPMs and OSCs who conduct
site characterization arid restoration.
1. There is no specific method or process that can be recom-
mended for sampling soils for VOk A wide variety of
sampling devices are currently used for collecting soil
samples for VOk Sampling device selection is site-specific,
and no single device can be recommended for use at all
sites. Several different samplers, which cover a broad
range of sampling conditions and circumstances, are rec-
ommended for obtaining representative samples for VOC
analysis (Table 7). Procedures may vary for different VOCs.
Expenmerits have shown that a procedure that collects an
undisturbed, intact sample with a device that allows direct
transfer to a sample container (e.g., split-spoon, Shelby
tube, or zero-contamination sampler) is supenor to a more
disruptive procedure that uses a crude bulk sampler (e.g.,
shovel, trowel, scoop, or spade) for maintaining the mntegnty
of VOCs in a soil sample. Large-diameter tube-type sam-
pling devices are recommended for collection of near-
surface samples The same types of devices can be used
in conjunction with hollow-stem augers for collecting sub-
surface samples
2. Transfer of the sample from the sampling device to the
container isa critical step in the process. Losses of as much
as 80% have been observed dun rig this step. The faster the
soil can be removed from the sampling device and
20
-------
TABLE 12.
METHODS FO
P VOC ANALYSIS OF SOIL
Method
Sample
$ ze
Sample
paradon
SenSItMty
OiaUly
Extrac o&analySI3
(9)
ProcedUre
(jig /kg)
ot . ctt , e
/ 8 5 Purge and trap 5-10 Li g on RCRA’ Sasap e transfer to
/8010 pwgeandtrapis
/8015
/8020
/8030
/8260
5380 / 8240 5-100 Methanol extraction 500-1000 RCRA Sensitivity loss but
/8010 etransfer
/8015 tacthtaled
/8020
/ 8030
/8260
5031 / 8240 5 Field purge 5-10 Seni- RCRA San e n only be
/8010 quantitative analyzed
/8015 fransferandshippng
/8020 faa6t ed.
/ 8030
/8260
3810/8240 10 Heatto9 OcC 1000 Screecmg RCRA Canbepeslodrned
/ 8010 in Water bath fix pwge fe in the fiefd.
/8015 andanaiyze orgajics
/8020 hea&cpace
/8030
/8260
3820 10 Hexadecsne 500-1000 Saeecwig RCRA FID responses vary
extraction pnortoGC thtype&VOC.
followedby orGC/MS
GC/FID analysis
624 5 Purge and trap 5-10 Litigation CJ.P Sum to method
5030 /8240 m
RCRA SW-848.
US EP&1986b
‘US EPk 1982
21
-------
transferred into ai airtight sample container, the smaJler
the VOC loss. Liners make the removal and subsamphng
of soil from the collection device more efficient.
3 The best method for transfemng a sample from a large-
diameter conng device (or exposed test pit) unto a sample
container is by collecting the appropnate size aluquot (for
laboratory analysis) with a small-diameter, hand-held corer
and extruding the subsample unto a 40-mL VOA viaJ, then
sealing the vial with a modified purge-and-trap cap. Alter-
natively, contents of the large-diameter conng device can
be sectioned and immersed in methanol
4 Small-diameter, hand-held corers can be used for col-
lecting samples from a freshly exposed face of a trench or
test pit, or for obtaining a subsample from a large-diameter
ccnng device The use of a small-diameter, hand-held
corer is recommended for obtaining subsamples from
liner-held soil Collection of a sample of the appropnate
size for a particular anaiytca] procedure us optimaL The
required size of aliquot cart be extruded into a 40-mL VOA
vial and sealed with a modified purge-and-trap cap. The
possibility exists of composuting several small-diameter
core samples by immersing them in a single jar containing
methanol
5 Sample containers vary in terms of air-tlghthess Data are
available to indicate that there is a dea’ease in pressure
and an na-ease in temperature in the cargo holds of certain
air caj’ners. This is the worst possible set of conditions for
maintaining VOCs in containenzed soil samples. Intact
seals on storage containers and adequate cooling is thus
critical for maintaining VOCs in soil samples. Shipping and
holding-time studies have shown that vials and jars may be
equally suited for containing VOCs in soil samples, the
laboratory pretreatment step needed to obtain an aliquot
from a jar-held sample causes signrfi cant losses of VOCs
Commercially available shipping packages with built-in
cooling matenals (e g.. Freeze Gel Packs® or Blue Ice®)
are available. Whenever possible, art integrated sampling
approach should be employed to obtain the most represen-
tative samples possible. Soul-gas surveying coupled with
on-site soil sampling and analyses followed by the Re-
source Conservation and Recovery Act (RCRA) or CLP
laboratory analyses may provide valuable information on
the partitioning of VOCs at a site -
6. The current preservation technique for soil samples is
storage at 4°C in the da& Biological activity may continue
at this temperature. The addition of mercunc chlonde to the
soil may reduce biodegradation of VOCs. The amount of
mercunc ctilonde to be added, however, isa function of the
organic carbon content in the soil The most promising
preservatives for reducing losses of VOCs through volatil-
ization are solid adsorbents such as Molecular Sieve - 5A’
and RorasW ’
22
-------
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