United States
Environmental Protection
Agency
Environmental Monitoring Systems -
Laboratory
Las Vegas NV 89114
Research and Development
EPA-600/S4-83-040 Jan. 1
x>EPA Project Summary
Characterization of Hazardous
Waste Sites - A Methods
Manual, Volume II, Available
Sampling Methods
P.E. Ford, P.J. Turina, and D.E. Seely
This volume is a compilation of
methods and materials suitable to
address most needs that arise during
routine waste site and hazardous spill
investigations. It is part of a multivolume
manual developed by the U.S. Environ-
mental Protection Agency to serve a
wide variety of users as a source of
information, methods, materials and
references on the subject. This volume
is organized by media. After a first
introductory chapter on general problems,
the second chapter addresses solids
and provides eight detailed instructions
on sampling methods for soils, sludges
and sediments, and bulk materials.
Chapter Three addresses liquids. Ten
methods are detailed for surface waters,
containerized liquids, and groundwater.
Gases, vapors, and aerosols are covered
in Chapter Four. Twelve methods are
presented for ambient air, soil gases
and vapors, and headspace gases. The
last chapter briefly discusses ionizing
radiation survey instruments. Every
method is referenced, and a large
bibliography is provided. Appendices
are included to make the volume a
useful field manual. They cover Sample
Containerization and Preservation,
Equipment Availability and Fabrication,
Packing and Shipping Guidelines,
Document Control and Chain-of-Custody
Procedures, and Applicable Tables (of
statistics and conversion factors). This
volume will be revised annually.
This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Las Vegas, NV, to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Investigations at hazardous waste and
environment-threatening spill sites place
more restrictive demands on personnel,
materials and methodologies than those
usually found in routine environmental
surveys. As a result, traditional procedures
and protocols used for the acquisition of
environmental samples often fail to meet
the rigors and demands required for
many hazardous waste sampling applica-
tions. Thus, the collection of hazardous
waste samples will frequently require
specialized equipment and protocols
either developed specifically for such
uses or modified from preexisting.materials
and/or techniques. Some important
considerations are:
Methods and materials must be
suitable to a wide range of situations
and applications because of the
unknown nature of many hazardous.
waste investigations and environ-
mental spill responses.
Hazardous wastes, by definition,
are associated with both acute and
chronic exposure to dangerous,.
toxic chemicals and this dictates
that expeditious sample collection
methods be used to minimize
personnel exposure.
Because of the nature of the
materials being sampled, the
option of using disposable sampling
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equipment must be considered
because attempting cleanup efforts
in the field can be impractical.
Hazardous waste site investigations
and response actions at environ-
ment-threatening spills generally
require some level of hazard
protection that may be cumbersome,
limit the field of vision, or fatigue
the sampler. Sample collection
procedures must therefore be
relatively simple to follow to
expedite sample procurement and
to reduce the chance of fatigue.
Collection and monitoring equip-
ment should be simple to operate,
direct reading, and should not be
unwieldy.
These and other factors associated with
the procurement of hazardous waste
samples need to be addressed in a
compilation of practical, cost effective,
and reliable methods and procedures
capable of yielding representative samples
for a diverse number of potential parameters
and chemical matrices. These methods
must be consonant with a variety of
analytical considerations running the
gamut from gross compatibility analyses
(pH, flammability, water reactivity, etc.) to
highly sophisticated techniques capable
of resolution in the part per billion (ppb)
range.
Method Selection Criteria
Even a limited literature survey will
disclose the existence of a great number
of sampling methods, all of which have
certain merits that warrant consideration.
Therefore, selection criteria were chosen
on which to base decisions for including
the sampling methods found in this
manual. The following is a listing, not
necessarily in order of relative importance,
of these criteria:
Practicality
Representativeness
Economics
Simplicity or Ease of Operation
Compatibility with Analytical Con-
siderations
Versatility
Safety
Purpose and Objectives of
Sampling
The basic objective of any sampling pro-
gram is to produce a set of samples
representative of the source under
investigation and suitable for subsequent
analysis. More specifically, the objective
of sampling hazardous wastes is to
acquire information that will assist
investigators in identifying unknown
compounds present and to assess the
extent to which these compounds have
become integrated into the surrounding
environment. Subsequently, this ac-
quired information may be used in future
litigations as well as to assist investigators
in the development of remedial actions.
The term "sample" can most simply be
defined as a representative part of the
object to be analyzed. This definition
needs to be qualified further, however, by
the consideration of several criteria.
Of utmost importance is representa-
tiveness. To meet the requirement of re-
presentativeness, the sample needs to be
chosen so that it possesses the same
qualities or properties as the material
under consideration. However, the sam-
ple needs only resemble the material to
the degree determined by the desired
qualities under investigation and the
analytical techniques used.
Sample size is also an important
criterion to be considered. Sample size
must be carefully chosen with respect to
the physical properties of the entire
object and the requirements and/or
limitations of the analytical procedure.
For example, although the entire contents
of an intact 55-gallon drum can certainly
be considered a representative sample of
the drum material, it is an impractical
sample because of its bulk. Alternatively,
too small a sample size can be just as
limiting, since representativeness and
analytical volume requirements might be
jeopardized.
A third criterion for consideration is
maintenance of sample integrity. The
sample must retain the properties of the
parent object (at the time of sampling)
through collection, transport, and delivery
to the analyst. Degradation or alteration of
the sample through exposure to air,
excess heat or cold, microorganisms, or
to contaminants from the container must
be avoided.
Finally, the number and/or the fre-
quency of subsamples (e.g., samples
making up a composite) required and the
distribution of these subsamples need to
be considered.These criteria are often
dictated by the nature of the material
being sampled; that is, whether the
material is homogeneous or heterogeneous.
For example, if a material is known to be
homogeneous, a single sample may
suffice to define its quality. However, if a
sample is heterogeneous, a number of
samples collected at specified time inter-
vals or distances may be necessary to de-
fine the characteristics of the subject
materials. In addition, the nature of the
chemical parameters to be identified and
the way the analytical results will be used
are also important when the number
and/or frequency of the samples to be
collected are determined.
Types of Samples
Before defining the general sample
types, the nature of the object or
materials under investigation must be
discussed. Materials can be divided into
three basic groups as outlined in Figure
1.
Of least concern to the sampler are
homogeneous materials. These materials
are generally defined as having uniform
composition throughout. In this case, any
sample increment can be considered
representative of the material. On the
other hand, heterogeneous samples
present problems to the sampler because
of changes in the quality of the material
over distance.
When discussing types of samples, it is
important to distinguish between the type
of media to be sampled and the sampling
technique that yields a specific type of
sample. In relation to the media to be
sampled, two basic types of samples can
be considered: the environmental sample
and the hazardous sample.
Environmental samples (ambient air,
soils, rivers, streams, or biota) are
generally dilute (in terms of pollutant
concentration) and usually do not require
the special handling procedures used for
concentrated wastes. However, in certain
instances, environmental samples can
contain elevated concentrations of
pollutants and in such cases would have
to be handled as hazardous samples.
Hazardous or concentrated samples
are those collected from drums, tanks,
lagoons, pits, waste piles, fresh spills,
etc., and require special handling proce-
dures because of their potential toxicity or
hazard. These samples can be further
subdivided based on their degree of
hazard; however, care should be taken
when handling and shipping any wastes
believed to be concentrated, regardless of
the degree.
In general, two basic types of sampling
techniques are recognized, both of which
can be used for either environmental or
concentrated samples.
Grab Samples
A grab sample is defined as a discrete
aliquot representative of a specific
location at a given point in time. The
sample is collected all at once and at one
particular point in the sample medium.
The representativeness of such samples
is defined by the nature of the materials
being sampled. In general, as sources
vary over time and distance, the repre-
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Material
Homogeneous
No change of quality
throughout the material
Heterogeneous
\ \
Discrete Continuous
Change of quality Change of quality
throughout the material throughout the material
Homogeneous
Discrete Changes
Continuous Changes
Well-mixed liquids
Well-mixed gases
Pure metals
Ore pellets
Tablets
Crystallized rocks
Suspensions
Fluids or gases with gradients
Mixture of reacting compounds
Granulated materials with granules
much smaller than sample size
Figure 1. Types of material
sentativeness of grab samples will
decrease.
Composite Samples
Composites are nondiscrete samples
composed of more than one specific
aliquot collected at various sampling
locations and/or different points in time.
Analysis of this type of sample produces
an average value and can in certain
instances be used as an alternative to
analyzing a number of individual grab
samples and calculating an average
value. It should be noted, however, that
compositing can mask problems by
diluting isolated concentrations of some
hazardous compounds below detection
limits.
For sampling situations involving
hazardous wastes, grab sampling tech-
niques are generally preferred because
grab sampling minimizes the amount of
time sampling personnel must be in
contact with the wastes, reduces risks
associated with compositing unknowns,
and eliminates chemical changes that
might occur due to compositing. Com-
positing is still often used for environ-
mental samples and may be used for
hazardous samples under certain condi-
tions. For example, compositing of
hazardous waste is often performed (after
compatibility tests have been completed)
to determine an average value over a
number of different locations (group of
drums). This procedure provides data that
can be useful by providing an average
concentration within a number of units,
can serve to keep analytical costs down
and can provide information useful to
transporters and waste disposal opera-
tions.
Sampling Plan
Before any sampling activities are
begun, it is imperative that the purpose
and goals of a program and the equipment,
methodologies, and logistics to be used
during the actual sampling be identified
in the form of a work or sampling plan.
This plan is developed when it becomes
evident that a field investigation is
necessary and should be initiated in
conjunction with or immediately following
the preliminary assessment. This plan
should be clear and concise and should
detail the following basic components:
background information collected
during the preliminary assessment;
objectives and goals of the investi-
gation;
sampling methods to be used,
including equipment needs, pro-
cedures, sample containment, and
preservation;
justification for selected methods
and procedures;
sample locations, as well as, number
and types of samples to be collected
at each;
organization of the investigative
team;
safety plan (includes safety equip-
ment and decontamination pro-
cedures, etc.);
transportation and shipping inform-
ation;
training information; and
additional site-specific information
or requirements.
Note that this list of sampling plan
components is by no means all inclusive
and that additional elements may be
added or altered depending on the
specific requirements of the field investi-
gation. It should also be recognized that
although a detailed sampling plan is quite
important, it may be an impractical
undertaking in some instances. Emergency
responses to accidental spills would be a
prime example of such an instance where
time might prohibit the development of a
site-specific sampling plan. In such a
case, the investigator would have to rely
on general guidelines and personal
judgment, and the sampling or response
plan might be simply a strategy based on
preliminary information and finalized on
site. In any event, a plan of action needs to
be developed, no matter how concise or
informal, to aid investigators in main-
taining a logical and consistent order to
the implementation of their task. Plan-
ning and safety are discussed in detail in
Volumes I, IV and V.
Sampling Schemes
The manner in which samples are
selected generally falls into one of (or a
combination of) the following categories.
Random Sampling
Random sampling uses the theory of
random chance probabilities to choose
representative sample locations. Random
sampling is generally employed when
little information exists concerning the
material, location, etc. It is most effective
when the population of available sampling
locations is large enough to lend statisti-
cal validity to the random selection
process. Since one of the main difficulties
with random sampling deals with achiev-
ing a truly random sample, it is advisable
to use a table of random numbers to
eliminate or reduce bias (Appendix E).
Systematic Sampling
Systematic sampling involves the
collection of samples at predetermined,
regular intervals. It is the most often
employed sampling scheme; however,
care must be exercised to avoid bias, if,
for example, there are periodic variations
in the material to be sampled such that
the systematic plan becomes partially
phased with these variations.
A systematic sampling plan is often the
end result for approaches that are
initiated as random due to the tendency of
investigators to subdivide a large sample
area into increments prior to randomizing.
Stratified Sampling
Data and background information
made available from the preliminary site
survey, prior investigations conducted on
site and/or experience with similar
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situations can be useful in reducing the
number of samples needed to attain a
specified precision. Stratified sampling
essentially involves the division of the
sample population into groups based on
knowledge of sample characteristics at
these divisions. The purpose of the
approach is to increase the precision of
the estimates made by sampling. This
objective should be met if the divisions
are "selected in such a manner that the
units within each division are more
homogeneous than the total population."
The procedure used basically involves
handling each division in a simple
random approach.
Judgment Sampling
A certain amount of judgment often
enters into any sampling approach used;
however, this practice should be avoided
whenever possible, especially if the data
generated are likely to be used for
enforcement purposes. Judgment ap-
proaches tend to allow investigator bias to
influence decisions, and, if care is not
exercised, can lead to poor quality data
and improper conclusions. If judgment
sampling does become necessary, it is
advisable that multiple samples be
collected in order to add some measure of
precision.
Hybrid Sampling Schemes
In reality, most sampling schemes
consist of a combination or hybrid of the
types previously described. For example,
when selecting an appropriate plan for
sampling drums at a hazardous waste
'site, the drums might be initially staged
based on preliminary information con-
cerning contents, program objectives,
etc. (judgment, stratified sampling), and
then sampled randomly within the
specified population groups (random
sampling). Hybrid schemes are usually
the method of choice as they can allowfor
greater diversity without compromising
the objectives of the program.
Multiple Samples
Multiple samples need to be collected
at any time legal action is anticipated. It is
recommended that multiple samples be
collected whenever possible. These
additional samples are essential to any
quality control aspects of the project and
may also assist in reducing costs associ-
ated with resampling brought about by
container breakage, errors in the analytical
procedure, and data confirmation. The
following is a list of the types of multiple
samples required.
Sample Blanks
Sample blanks are samples of deio-
nized/distilled water, rinsed collection
devices or containers, sampling media
(e.g., sorbent), etc. that are handled in the
same manner as the sample and sub-
sequently analyzed to identify possible
sources of contamination during collec-
tion, preservation, handling, or transport.
Duplicates
Duplicates are essentially identical
samples collected at the same time, inthe
same way, and contained, preserved, and
transported in the same manner. These
samples are often used to verify the
reproducibility of the data.
Split Samples
Split samples are duplicate samples
given to the owner, operator, or person in
charge for separate analysis.
Spiked Samples
Spiked samples are duplicate samples
that have a known amount of a substance
of interest added to them. These samples
are used to corroborate the accuracy of
the analytical technique and could be
used as an indicator of sample quality
change during shipment to the laboratory.
Document Control/Chain-of-
Custody
Strict adherence to document and data
control procedures is essential from the
standpoint of good quality assurance/
quality control and should be instituted as
routine in any hazardous waste investi-
gation. It becomes especially important
when collected data is used to support
enforcement litigations. All collected
information, data, samples, and docu-
ments must therefore be accounted for
and retrievable at any time during an
investigation.
The purpose of document control is to
ensure that all project documents be
accounted for when the project is
complete. Types of documents considered
essential include maps, drawings, photo-
graphs, project work plans, quality
assurance plans, serialized logbooks,
data sheets, coding forms, confidential
information, reports, etc.
Chain-of-custody procedures are ne-
cessary to document the sample identity,
handling and shipping procedures, and in
general to identify and assure the
traceability of generated samples. Custody
procedures trace the sample from collec-
tion, through any custody transfers, and
finally to the analytical facility at which
point internal laboratory procedures take
over. Chain-of-custody is also necessary
to document measures taken to prevent i
and/or detect tampering with samples,
sampling equipment or the media to be
sampled. A detailed description of
Document Control/Chain-of-Custody
Procedures can be found in Appendix D.
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P. E. Ford. P. J. Turina. andD. E. Seelyare with GCA Corp., Bedford. MA 01730.
Charles K. Fitzsimmons is the EPA Project Officer (see below).
The complete report, entitled "Characterization of Hazardous Waste SitesA
Methods Manual: Volume II. Available Sampling Methods," (Order No. PB
84-126 929; Cost: $20.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Las Vegas, NV 89114
-snAL MAIL.
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
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