United States
                       Environmental Protection
                Solid Waste And
                Emergency Response
 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

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
                                  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-
                                  * Procuring subcontractors, equip-
                                   ment, and supplies
                                  * Selecting and coordinating with
                                   an analytical laboratory ,
                                  » Procuring onsite facilities for RI
                                  •• Providing for storage/disposal of
                                   contaminated materials gener-
                                   ated during the RI
Figure 1. Major Components of the Remedial Investigation

 Define Site Physical
 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

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
 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

 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

 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-
•  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

Preliminary Site Characterization

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

may be more extensive and review the
investigative activities that have taken

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-
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-
•  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-
*  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.

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

  •• 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

  • Turn data over to contractors for
    pre-analysls before data valida-

  • Develop  and  implement  the
    treatability testing program dur-
    ing the RI.

  • Continue theidentiflcationofcon-
    taminant- and location-specific

  * Communicate  regulatiy with all
    involved parties.             •

  * Incorporate TAG  participation
    throughout the RI