United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-220)
530R89120
EPA The Remedial Investigation
Site Characterization and
Treatability Studies
This fact sheet is the second in a series
of four that describes the remedial inves-
tigation/feasibility study (RI/FS) pro-
cess. Included within this fact sheet is a
summary of Chapters 3 and 5 of the
Interim Final Guidance for Conducting
Remedial Investigations and Feasibility
Studies Under CERCLA (October 1988,
OSWER Directive No. 9355.3-01). These
chapters discuss site characterization
and treatability studies, respectively.
Also included is information on how to
manage these aspects of the remedial
investigation (RI).
The RI builds on activities initiated during
scoping and includes implementation of
the work plan (WP), the sampling and
analysis plan (SAP), and the health and
safety plan (HSP). Field data are col-
lected and analyzed to determine the
problems posed by a site and to support
the identification of potential remedial
actions. For sampling efforts to be better
focused, it may be desirable to conduct
iterative, and increasingly focused, field
investigation rounds. Thus, the RI ob-
jectives may be better balanced with
time and resource constraints. A sche-
matic of the major components that
comprise the RI is presented in Figure 1.
Treatability studies provide data on
remedial technologies and their effec-
tiveness on the specific waste found at a
site. Ideally, the need for these investiga-
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ttons is identified during scoping, while
the testing program is developed and
implemented during the RI.
Remedial Investigation
Activities
Conduct Field Investigations
Field investigations define a site's
physical characteristics as well as its
sources, nature, and extent of
contamination. In addition to
characterizing a site, these activities may
also be conducted to gather data on
required design/operation parameters
for the technologies being considered for
remedial action. Because the RI and FS
are interactive processes that are
conducted concurrently. field
investigation activities will be ongoing
during the development and screening
of remedial action alternatives. Sampling
methods for obtaining site data are
outlined in the Compendium o/Super/und
Field Operations Methods (September
1987. OSWER Directive No. 9355.0-14);
relevant chapters from this compendium
are noted on Table 3-1 of the RI/FS
Guidance.
Note: Support activities are re-
quired before conducting field in-
vestigations «nd may take several
month* to be completed. Activi-
ties may include:
» Obtaining access to areas of in-
vestigation
* Procuring subcontractors, equip-
ment, and supplies
* Selecting and coordinating with
an analytical laboratory ,
» Procuring onsite facilities for RI
activities
Providing for storage/disposal of
contaminated materials gener-
ated during the RI
Figure 1. Major Components of the Remedial Investigation
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Define Site Physical
Characteristics
Data on the site's physical characteris-
tics and the surrounding areas are col-
lected to: (1) define potential transport
pathways and receptor populations and
(2) provide sufficient engineering data to
develop and evaluate remedial action
alternatives. Information used to define
a site's physical characteristics includes:
Site surface features
'Site geology
Soil and vadose-zone characteristics
Site hydrogeology
Surface water hydrology
Meteorological data
Human population, land, and water
use data
Ecological information
These data may be obtained from a
variety of sources Including, but not
limited to: historical photographs, topo-
graphic surveys, site operational rec-
ords, sampling/monitoring results.
demographic information. USGS and
zoning maps, and interviews with pres-
ent/past site owners and employees.
Characterize Sources
of Contamination
Source characterization includes defin-
ing: (1) facility characteristics that iden-
tify source locations; (2) the quantity of
wastes that are either contained in, or
have been released in, the environment;
and (3) the physical and chemical char-
acteristics of wastes present in the
sources. As a part of source characteri-
zation, the location, type, and integrity
of waste containment structures (e.g.,
drums) are evaluated to determine the
potential for substance release and its
magnitude. The data required for source
characterization are typically obtained
through site Inspections, mapping.
remote sensing, and sampling and analy-
sis. Quantities of wastes are estimated
either from verifiable Inventories of con-
tainerized waste, from sampling and
analysis, or from physical dimensions of
the source.
Characterize Nature and Extent
qf Contamination
The final objective of the field Investi-
gation performed during the RI is to
investigate the extent of contaminant
migration. Including the volume of con-
tamination and any changes in its phys-
ical and chemical characteristics. This
process involves using the information
on physical site data and source location
for a preliminary estimate of the locations
of contaminants that may have migrated
into the environment. An iterative
monitoring program is then implemented
so that, using increasingly accurate
analytical techniques, the locations and
concentrations of contaminants that
have migrated can be denned. The final
step is to ensure that the extent of
contamination is confirmed with
adequate data of sufficient quality to
support riskassessmentand the analysis
of remedial alternatives.
The sampling and analysis approach
used to determine the extent of contami-
nation is discussed in Section 4.5.1 of
U.S. EPA's Data Quality Objectives far
Remedial Response Activities (March
1987. OSWERDirectiveNo. 9335.0-7B).
Note: Because of the inherent un-
certainties associated with Super-
fund cites, it is impossible to de-
finitively characterize the nature
and extent of contamination at a
site. Adequate site characteriza-
tion requires data that meet DQOs.
define the risks posed by a «Ue,
demonstrate clearly the need for
remedial action, and support the
rationale for electing a remedial
action alternative.
Perform Data Analysis
Laboratory Analys
The type of laboratory chosen to analyze
the site characterization samples may
include a mobile laboratory, a labora-
tory with whom the EPA has contracted
under the contract laboratory program,
(CLP), or a non-CLP laboratory. The type
of laboratory selected will depend on the
analytical services required, the number
of samples to be analyzed, and the de-
sired turnaround time. In many cases, it
may be appropriate for more than one
type of laboratory to be used. For ex-
ample, mobile or non-CLP laboratories
may be used for the quick analysis of
screening level samples, while selected
duplicate and/or split samples may be
sent to CLP laboratories to confirm and
validate the initial estimation of the
nature and extent of contamination.
Note: A combination of laboratory
services, adequate to achieve the
established DQO*. result* in more
effective use of time and money.
characteristics, sources of contamina-
tion, the nature and extent of contami-
nation, and the risk associated with the
contamination. Defining the risks to
human health and the environment is a
function of the baseline riskassessmen
The baseline risk assessment is ad-
dressed in a separate fact sheet entitled.
Risk Assessment Guidance far Super-
fund: Human Health Evaluation Manual.
This fact sheet is being prepared by the
Hazardous Site Evaluation Division in
the Office of Emergency and Remedial
Response.
Data Management
The quality and validity of information
generated during the RI must be effec-
tively tracked by a data management
system to allow it to be used to support
remedy selection and any legal or cost
recovery actions. The RI data manage-
ment system should include:
Field Logs-to document field investi-
gation activities and observations, field
measurements, -and any unusual
circumstances or occurrences.
Laboratory and QA/QC Reports-to
provide chaln-of-custody and sample
shipment records, analytical results,
adherence to prescribed protocols,
nonconformity events, correct*'
measures, and data deficiencies.
All records should be maintained
throughout the RI/FS to ensure that
only final and approved analytical data
are used in the site analyses. Precau-
tions should be taken to prevent the
introduction of errors or the loss or
misinterpretation of data. A data secu-
rity system should be created to safe-
guard and prevent free access to project
records.
Note: In some cave*, the use of non-
validated data la warranted to
prepare InteraalreviewdocumenU,
to begin data analyst*, and to
continue refining remedial action
alternative*. Preliminary data, how-
ever, can lead to improper conclu-
sions and are, therefore, consid-
ered unofficial. These data must be
updated upon receipt of QA/QC
The results of the RI are typically pre-
sented as an analysis of site physical
Define Contaminant Fate
and Transport
Results of the site physical characteriza-
tion, source characterization, and extent
of contamination analyses are combined
to determine and project contaminant
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fate and transport This involves deter-
mining the actual and potential magni-
tude of releases from the sources and
*he mobility and persistence of source
ntaminants.
If information on contaminant release is
available, the observed extent of con-
tamination maybe used In assessing the
transport pathways rate of migration
and the fate of contaminants over the
time span between release and monitor-
ing. Contaminantfate and transport may
also be estimated on the basis of site
physical and source characteristics.
Either type of analysis may be based on
semi-analytical, analytical, or numeri-
cal models. While field data generally
best define the extent of contamination,
models can interpolate among, and ex-
trapolate from, isolated field samples to
areas and times not sampled.
Note: Modeling techniques to de-
termine contaminant fate and
transport may not be necessary if
site conditions are well understood
and if the potential effectiveness of
different remedial actions can be
easily evaluated.
"define Contaminant- and
sOcation-Specific ARARs
Identification of potential applicable or
relevant and appropriate requirements
(ARARs) is initiated during scoping and
continues throughout site characteriza-
tion activities. During the RI, as a better
understanding is gained of site condi-
tions and contaminants, identification
of contaminant- and location-specific
ARARs continues to: (1) better plan fu-
ture field activities, including identifying
the scale of any required treatability
studies, and (2) identify remedial action
alternatives. The CERCLA Compliance
with Other Laws Manual (Part I - August
1988 and Part II - August 1989, OSWER
Directive Nos. 9234.1 and 9234.1-02)
contains detailed information on identi-
fying and complying with ARARs.
Evaluate Additional Data Needs
As data are collected, and a better un-
derstanding of the site and the risks that
it poses is obtained, the preliminary
remedial action alternatives, initially
identified during scoping, should be fur-
ther refined. The available data should
then be evaluated to determine if: (1) the
DQOs have been met (2) the risks posed
by the site have been adequately de-
fined, (3) the need (or lack of need) for
remedial action is documented, and (4)
the data necessary for the development
and evaluation of remedial action alter-
natives have been obtained. Site char-
acterization Is complete when these cri-
teria have been met.
Conduct Treatability Studies
The need for treatability testing should
be identified during project scoping to
avoid delays in the RI/FS schedule.
During scoping, a literature survey
should be conducted to gather informa-
tion on a technology's applicability,
performance, implementability, relative
costs, and operation and maintenance
requirements. If practical candidate
technologies have not been sufficiently
demonstrated or cannot be adequately
evaluated on the basis of available
information (e.g., characterization of a
waste alone is insufficient to predict
treatment performance or the size and
cost of treatment units) treatability
testing should be performed. The
treatability testing program will be
designed and Implemented during the
RI, while other field activities are under
way. Design and implementation of a
testing program will include:
Preparation of a WP. SAP. and HSP
Performance of field sampling, if re-
quired
Implementation of a testing program
Evaluation of test results and docu-
mentation in a report
If the project plans developed for the RI/
FS do not adequately define the activi-
ties to be performed during the treatabil-
ity studies, a WP, SAP, and HSP must be
developed before beginning the testing
program. The required contents of these
plans are listed in Appendix B of the RI/
FS Guidance.
The decision to use a bench- versus a
pilot-scale test is affected by a number of
factors, including the level of develop-
ment of the technology, the composition
of the waste, and the nature and repre-
sentativeness of the desired data. For a
technology that is well developed and
tested, bench studies may be sufficient
to evaluate performance on new waste
types. Pilot tests may be necessary if in-
formation needed to operate the tech-
nology at full scale Is limited, if there is
a need to investigate secondary effects of
the process, or if the waste being tested
is complex or unique.
Following the treatability testing pro-
gram, an evaluation report will be pre-
pared that analyzes and Interprets the
test results considering the technology's
effectiveness, Implementability, environ-
mental Impacts, and cost Full-scale
application of the technology will be
evaluated and should include the identi-
fication of key parameters and unknowns
that can affect full-scale operations.
Additional information on treatability
studies can be found in a document
entitled, Guide to Conducting TreatabH-
tty Studies under CERCLA. This guide is
currently being developed by the Office
of Research and Development in their
Risk Reduction and Engineering Labo-
ratory in Cincinnati, Ohio.
Note: The need for treatability stud-
ies will result from initiating the
alternative development process
during scoping. A Technical Advi-
sory Committee (TAG) should be
used to achieve early consensus on
potential remedial alternatives.
Once the need for treatability test-
ing has been identified, TAG
support should continue with
oversight of the development and
implementation of the testing
program as well as evaluation and
interpretation of test results. (See
Scoping Fact Sheet, OSWER
Directive No. 8355.3-O1FS1, for
additional information on the TAG.)
Remedial Investigation
Deliverables
Preliminary Site Characterization
Summary
The preliminary site characterization
summary is a concise summary of site
data. This summary is developed after
initial field efforts and: (1) provides a
vehicle for the early sharing of ARARs
with the support agency, (2) allows for
early refinement of remedial alternatives,
and (3) can be transmitted to the Agency
for Toxic Substances and Disease Regis-
try so that they may begin their required
health assessment
The format of the preliminary site char-
acterization summary will be determined
by the Region. The summary may be
nothing more than a list of contaminants
of concern and the affected media, or it
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may be more extensive and review the
investigative activities that have taken
place.
Draft RI Report
The RPM reviews and approves the draft
RI report after completion of RI activi-
ties. This report summarizes the results
of the field activities to characterize the
nature and extent of contamination, the
fate and transport of contaminants, and
the results of the baseline risk assess-
ment Table 3-13 In the RI/FS Guidance
provides a suggested RI report format.
RPM Responsibilities
The RPM Is responsible for managing the
project to meet the RI/FS objectives
within the time and cost constraints.
These responsibilities Include ensuring
that adequate technical support is pro-
vided, as well as schedule maintenance
and financial control of the project
Technical Support
Techniques to assist In ensuring that
adequate technical support Is provided
to the project during the RI Include:
Incorporate TAG participation
throughout the RI to identify and
resolve technical issues. When treat-
ment is being considered for complex
or difficult to treat waste, it is appro-
priate for ORD's START team to be
included on the TAG. See the Scoping
Fact Sheet (OSWER Directive No.
9355.301FS1) for additional infor-
mation on the START team and other
technical experts.
Communicate on a regular basis with
all Involved parties (support agen-
cies, consultants. TAG members) to
reach a consensus on issues of con-
cern and/or additional site work.
Carefully consider the choice of ana-
lytical services to minimize the time
required to process samples while
maintaining the needed data quality
level. Consider the contractor's abil-
ity to perform or subcontract analyti-
cal services.
Ensure that contractors performing
treatability studies have adequate
experience and the necessary per-
mits.
Schedule and Cost Control
The management techniques listed under
technical support also assist in control-
ling schedule and cost Other schedule
and cost control techniques include:
When possible, provide conditional
approval to portions of the work plan
to begin field activities early.
Be aware that Basic Ordering Agree-
ments can be used by consultants to
expedite the procurement of subcon-
tractors.
Consider weather conditions when
scheduling field activities', extreme
weather conditions may delay the
schedule and/or Increase costs.
Ensure that field contractors are
trained in CLP procedures, including
sample collection, shipment, and
chain-of-custody requirements, to
minimize the need to resample.
Consider directing contractors to
validate field data.
Holdreviewmeetlngswlthallinvolved
parties to expedite review of deltver-
ables.
* Review monthly financial statements
from consultants and make sure that
all costs are justifiable.
Understand the components of labor
hour costs and verify that activities
are conducted by appropriate per-
sonnel at the most effective level.
Learn to anticipate cost and schedule
problems based on the contactor's
previous month's performance and
take actions to minimize cost over-
runs and schedule delays.
Enforcement
Considerations
Potentially responsible parties (PRPs)
may conduct all RI activities, Including
any required treatability studies. It
should be noted, however, that EPA
reserves the right to conduct any aspect
of the RI. As an example. EPA may
conduct the baseline risk assessment
since it serves as a primary means for
supporting enforcement decisions. Both
the administrative order (AO) and ap-
proved WP represent the negotiated
agreement between EPA and the PRPs
on how the RI is to be conducted. Modi-
fications to the scope of work must be
approved by EPA before Implementation.
As required by SARA. EPA will oversee all
PRP activities with the assistance of a
qualified third party. The objectives of
such oversight include verifying that:
(1) the RI/FS complies with CERCLA. *'
NCP, and relevant Agency guidance;
the work complies with the AO. State-
ment of Work. WP. and SAP, (3) all work
is performed to accordance with accept-
able scientific and engineering methods;
and (4) an adequate data base is devel-
oped to support subsequent decisions
and actions, either in the case of litiga-
tion or the development of the Record of
Decision. Additional Information on PRP
participation in the RI/FS and PRP over-
sight can be found in Appendix A of the
RI/FS Guidance and in OWPE's Model
Statement ofWofkforPRP-ConductedRe-
medial Investigations and Feasibility
Studies (June 2. 1989).
Points to Remember
» Initiate field support actlvttle'
early and allow enough time i
the schedule to complete them,
Use DQOs to determine the qual-
ity of data needed from each field
activity.
Create a data management sys-
tem for all RI activities.
» Minimize the need to mobilize/
demobilize contractors.
Use field-screening techniques
and mobile laboratories, where
appropriate.
Turn data over to contractors for
pre-analysls before data valida-
tion.
Develop and implement the
treatability testing program dur-
ing the RI.
Continue theidentiflcationofcon-
taminant- and location-specific
ARARs.
* Communicate regulatiy with all
involved parties.
* Incorporate TAG participation
throughout the RI
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