United States
Environmental Protection
Agency
Solid Waste And
Emergency Response
(OS-220)
Directive 9355.3-01 FS2
November 1989
&EPA The Remedial Investigation
Site Characterization and
Treatabilty Studies
This fact sheet is the second in a series of four
that describes the remedial
investigation/feasibility study (RI/FS)
process. 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 collected 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 objectives
may be better balanced with time and resource
constraints. A schematic 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 investigations
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 of Superfund 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.
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Figure 1. Major Components of the Remedial Investigation
Note: Support activities are required
before conducting field investigations and
may take several months to be completed.
Activities may include:
Obtaining access
investigation
to areas of
Procuring subcontractors,equipment,
and supplies
Selecting and coordinating with an
analytical laboratory
Procuring onsite facilities for RI
activities
Providing for storage/disposal of
contaminated materials generated
during the RI
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Define Site Physical
Ch aracteristics
Data on the site's physical characteristics and
the surrounding areas are collected 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, topographic surveys, site
operational records, sampling/monitoring
results, demographic information, USGS and
zoning maps, and interviews with present/past
site owners and employees.
Characterize Sources of
Contamination
Source characterization includes defining: (1)
facility characteristics that identify 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 characteristics of wastes present in
the sources. As a part of source
characterization, 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 obtainedthrough
site inspections, mapping, remote sensing,
and sampling and analysis. Quantities of
wastes are estimated either from verifiable
inventories of containerized waste, from
sampling and analysis, or from physical
dimensions of the source.
Characterize Nature and Extent of
Contamination
The final objective of the field investigation
performed during the RI is to investigate the
extent of contaminant migration, including the
volume of contamination and any changes in
its physical 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
defined. The final step is to ensure that the
extent of contamination is confirmed with
adequate data of sufficient quality to support
risk assessment and the analysis of remedial
alternatives.
The sampling and analysis approach used to
determine the extent of contamination is
discussed in Section 4.5.1 of U.S. EPA's Data
Quality Objectives for Remedial Response
Activities (March 1987, OSWER Directive No.
9335.0-7B).
Note: Because of the inherent
uncertainties associated with Superfund
sites, it is impossible to definitively
characterize the nature and extent of
contamination at a site. Adequate site
characterzation requires data that meet
DQOs, define the risks posed by a site,
demonstrate clearly the need for remedial
action, and support the rationale for
selecting a remedial action alternative.
Perform Data Analysis
Laboratory Analyses
The type of laboratory chosen to analyze the
site characterization samples may include a
mobile laboratory, a laboratory 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 desired turnaround time. In
many cases, it may be appropriate for more
than one type of laboratory to be used. For
example, 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 DQOs,
results in more effective use of time and
money.
Data Evaluation
The results of the RI are typically presented as
an analysis of site physical characteristics,
sources of contamination, the nature and
extent of contamination, and the risk
associated with the contamination. Defining
the risks to human health and the environment
is a function of the baseline risk assessment.
The baseline risk assessment is addressed in
a separate fact sheet entitled, Risk Assessment
Guidance for Superfund: Human Health
Evaluation Manual. This fact sheet is being
prepared by the Hazardous Site Evaluation
Divisbn in the Office of Emergency and
Remedial Response.
Data Management
The quality and validity of information
generated during the RI must be effectively
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
management system should include:
•	Field Logs-to document field
investigation activities and observations,
field measurements, and any unusual
circumstances or occurrences.
•	Laboratory and QA/QC Reports-to
provide chain-of-custody and sample
shipment records, analytical results,
adherence to prescribed protocols,
nonconformity events, corrective
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. Precautions should be taken to
prevent the introduction of errors or the loss
or misinterpretation of data. A data security
system should be created to safeguard and
prevent free access to project records.
Note: In some cases, the use of non-
validated data is warranted to prepare
internal review documents, to begin data
analysis, and to continue refining remedial
action alternatives. Preliminary data,
however, can lead to improper conclusions
and are, therefore, considered unofficial.
These data must be updated upon receipt of
QA/QC comments.
Define Contaminant Fate
and Transport
Results of the site physical characterization,
source characterization, and extent of
contamination analyses are combined to
determine and project contaminant
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fate and transport. This involves determining
the actual and potential magnitude of releases
from the sources and the mobility and
persistence of source contaminants.
If information on contaminant release is
available, the observed extent of
contamination maybe used in assessing the
transport pathway's rate of migration and the
fate of contaminants over the time span
between release and monitoring. Contaminant
fate 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
numerical models. While field data generally
best define the extent of contamination,
models can interpolate among, and extrapolate
from, isolated field samples to areas and times
not sampled.
Note: Modeling techniques to determine
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
Location-Specific ARARs
Identification of potential applicable or
relevant and appropriate requirements
(ARARs) is initiated during scoping and
continues throughout site characterization
activities. During the RI, as a better
understanding is gained of site conditions and
contaminants, identification of contaminant-
and location-specific ARARs continues to: (1)
better plan future 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 identifying 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 further 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 defined, (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 alternatives
have been obtained. Site characterization is
complete when these criteria have been met.
Conduct Treatability Studies
The need for treatability testing should be
identified during project scoping to avoid
delays in theRI/FS schedule. During scoping,
a literature survey should be conducted to
gather information 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 required
•	Implementation of a testing program
•	Evaluation of test results and
documentation in a report
If the project plans developed for the RI/FS do
not adequately define the activities to be
performed during the treatability 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 development of
the technology, the composition of the waste,
and the nature and representativeness 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
information needed to operate the technology
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 program, an
evaluation report will be prepared that
analyzes and interprets the test results
considering the technology's effectiveness,
implementability, environmental impacts, and
cost. Full-scale application of the technology
will be evaluated and should include the
identification 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 Treatability Studies under
CERCLA. This guide is currently being
developed by the Office of Research and
Development in their Risk Reduction and
Engineering Laboratory in Cincinnati, Ohio.
Note: The need for treatability studies will
result from initiating the alternative
development process during scoping. A
Technical Advisory Committee (TAC)
should be used to achieve early consensus
on potential remedial alternatives. Once
the need for treatability testing has been
identified, TAC support should continue
with oversight of the development and
implementation of the testing program as
well as evaluation and interpretation of test
results. (S eeScoping Fact Sheet, OSWER
Directive No. 9355.3-01FS1, for additional
information on the TAC.)
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
Registry so that they may begin their required
health assessment.
The format of the preliminary site
characterization 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 activities. 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 assessment. Table 3-13 in the RI/FS
Guidance provides a suggested RI report
format.
RPM Responsibilities
The RPM is responsible for managing the
proj ect to meet the RI/F S obj ectives within the
time and cost constraints. These
responsibilities include ensuring that
adequate technical support is provided, 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 TAC participation
throughout the RI to identify and resolve
technical issues. When treatment is
being considered for complex or difficult
to treat waste, it is appropriate for ORD's
START team to be included on the TAC.
See the Scoping Fact Sheet (OSWER
Directive No. 9355.301FS1) for additional
information on the START team and
other technical experts.
•	Communicate on a regular basis with all
involved parties (support agencies,
consultants, TAC members) to reach a
consensus on issues of concern and/or
additional site work.
•	Carefully consider the choice of analytical
services to minimize the time required to
process samples while maintaining the
needed data quality level. Consider the
contractor's ability to perform or
subcontract analytical services.
•	Ensure that contractors performing
treatability studies have adequate
experience and the necessary permits.
Schedule and Cost Control
The management techniques listed under
technical support also assist in controlling
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 Agreements
can be used by consultants to expedite
the procurement of subcontractors.
•	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.
•	Hold review meetings with all involved
parties to expedite review of deliverables.
•	Reviewmonthly 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 personnel 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 overruns 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 approved
WP represent the negotiated agreement
between EPA and the PRPs on how the RI is
to be conducted. Modifications 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 CERCL A, the NCP, and relevant
Agency guidance; (2) the work complies with
the AO, Statement of Work, WP, and SAP; (3)
all work is performed in accordance with
acceptable scientific and engineering
methods; and (4) an adequate data base is
developed to support subsequent decisions
and actions, either in the case of litigation or
the development of the Record of Decision.
Additional information on PRP participation in
the RI/FS and PRP oversight can be found in
Appendix A of the RI/FS Guidance and in
OWPE's Model Statement of Work for
PRP-ConductedRemedial Investigations and
Feasibility Studies (June 2, 1989).
a
Points to Remember
•	Initiate field support activities early and
allow enough time in the schedule to
complete them.
•	Use DQOs to determine the quality of
data needed from each field activity.
•	Create a data management system 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-
analysis before data validation.
•	Develop and implement the treatability
testing program during the RI.
•	Continue the identification of
contaminant- and location-specific
ARARs.
•	Communicate regularly with all involved
parties.
•	Incorporate TAC participation
throughout the RI.
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