UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, B.C. 20460
i FEB122002
U.S EPA Headquarters LJorary
Mail code 3404T
1200 Pennsylvania Avenue NW
Washington, DC 20460
202-566-0556
OFFICE OF
SOLID WASTE AND EMERGENCY
RESPONSE
OSWER Directive 9285.6-08
MEMORANDUM
SUBJECT: Principles for Managing Contaminated Sediment Risks at Hazardous Waste Sites
FROM:
TO:
Marianne Lament Horinko /s/
Assistant Administrator
Superfund National Policy Managers, Regions 1-10
RCRA Senior Policy Advisors, Regions 1-10
I. PURPOSE
This guidance will help EPA site managers make scientifically sound and nationally consistent
risk management decisions at contaminated sediment sites. It presents 11 risk management principles
that Remedial Project Managers (RPMs), On-Scene Coordinators (OSCs), and RCRA Corrective
Action project managers should carefully consider when planning and conducting site investigations,
involving the affected parties, and selecting and implementing a response.
This guidance recommends that EPA site managers make risk-based site decisions using an
iterative decision process, as appropriate, that evaluates the short-term and long-term risks of all
potential cleanup alternatives consistent with the National Oil and Hazardous Substances Pollution
Contingency Plan's (NCP's) nine remedy selection criteria (40 CFR Part 300.430). EPA site
managers are also encouraged to consider the societal and cultural impacts of existing sediment
contamination and of potential remedies through meaningful involvement of affected stakeholders.
This guidance also responds in part to the recommendations contained in the National Research
Council (NRC) report discussed below.
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II. BACKGROUND
On March 26,2001, the NRC published a report entitled .4 Risk Management Strategy for
PCB-Contaminated Sediments. Although the NRC report focuses primarily on assessment and
remediation of PCB-contatninated sediments, much of tiie information in that report is applicable to
other contaminants. Site managers are encouraged to read the NRC report, which may be found at
http://www.nrc.edu.
In addition to developing these principles, OSWER, in coordination with other EPA offices
(Office of Research and Development, Office of Water, and others) and other federal agencies
(Department of Defense/U.S. Army Corps of Engineers, Department of Commerce/National Oceanic
and Atmospheric Administration, Department of the Interior/US. Fish and Wildlife Service, and others
is developing a separate guidance, Contaminated Sediment Remediation Guidance for Hazardous
Waste Sites (Sediment Guidance). The Sediment Guidance will provide more detailed technical
guidance on the process that Superfund and RCRA project managers should use to evaluate cleanup
alternatives at contaminated sediment sites.
While this directive applies to all contaminants at sediment sites addressed under CERCLA or
RCRA, its implementation at particular sites should be tailored to the size and complexity of the site, to
the magnitude of site risks, and to the 1ype of action contemplated. These principles can be applied
within the framework of EPA's existing statutory and regulatory requirements.
III. RISK MANAGEMENT PRINCIPLES
1. Control Sources Early.
As early in the process as possible, site managers should try to identify all direct and indirect
continuing sources of significant contamination to the sediments under investigation. These sources might
include discharges from industries or sewage treatment plants, spills, precipitation runoff, erosion of
contaminated soil from stream banks or adjacent land, contaminated groundwater and non-aqueous
phase liquid contributions, discharges from storm water and combined sewer outfalls, upstream
contributions, and air deposition.
Next, site managers should assess which continuing sources can be controlled and by what
mechanisms. It may be helpful to prioritize sources according to their relative contributions to site risks.
In the identification and assessment process, site managers should solicit assistance from those with
relevant information, including regional Water, Air, and PCB Programs (where applicable); state
agencies (especially those responsible for setting Total Maximum Daily Loads (TMDLs) and those that
issue National Pollutant Discharge Elimination System (NPDES) permits); and all Natural Resource
Trustees. Local agencies and stakeholders may also be of assistance in assessing which sources can be
controlled.
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Site managers should evaluate the potential for future recontamination of sediments when
selecting a response action. If a site includes a source that could result in significant recontamination,
source control measures will likely be necessary as part of that response action. However, where EPA
believes that the source can be controlled, or where sediment remediation will have benefits to human
health and/or the environment after considering the risks caused by the ongoing source, it may be
appropriate for the Agency to select a response action for the sediments prior to completing all source
control actions. This is consistent with principle #5 below, which indicates that it may be necessary to
take phased or interim actions (e.g., removal of a hot spot that is highly susceptible to downstream
movement or dispersion of contaminants) to prevent or address environmental impacts or to control
human exposures, even if source control actions have not been undertaken or completed.
2. Involve the Community Early and Often.
Contaminated sediment sites often involve difficult technical and social issues. As such, it is
especially important that a project manager ensure early and meaningful community involvement by
providing community members wilh the technical information needed for Iheir informed participation.
Meaningful community involvement is a critical component of Ihe site characterization, risk assessment,
remedy evaluation, remedy selection, and remedy implementation processes. Community involvement
enables EPA to obtain site information that may be important in identifying potential human and
ecological exposures, as well as in understanding the societal and cultural impacts of the contamination
and of the potential response options. The NRC report (p. 249) "recommends that increased efforts be
made to provide the affected parties with the same information that is to be used by Ihe
decision-makers and to include, to the extent possible, all affected parties in the entire decision-making
process at a contaminated site. In addition, such information should be made available in such a manner
1hat allows adequate time for evaluation and comment on the information by all parties." Through
Technical Assistance Grants and otfier mechanisms, project managers can provide the community with
the tools and information necessary for meaningful participation, ensuring their early and continued
involvement in the cleanup process.
Although the Agency has the responsibility to make the final cleanup decision at CERCLA and
RCRA sites, early and frequent community involvement facilitates acceptance of Agency decisions.
even at sites where there may be disagreement among members of the community on the most
appropriate remedy.
Site managers and community involvement coordinators should take into consideration the
following six practices, which were recently presented in OSWER Directive 9230.0-99 Early and
Meaningful Community Involvement (October 12, 2001). This directive also includes a list of other
useful resources and is available at http://www. epa gov/superiiind/pubs.htm.
(1) Energize 1he community involvement plan.
(2) Provide early, proactive community support
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(3) Get the community more involved in ihe risk assessment
(4) Seek early community input on the scope of the remedial investigation/feasibility study
(RI/FS).
(5) Encourage community involvement in identification of future land use.
(6) Do more to involve communities during removals,
3. Coordinate with States, Local Governments, Tribes, and Natural Resource Trustees.
Site managers should communicate and coordinate early with states, local governments, tribes,
and all Natural Resource Trustees. By doing so, they will help ensure that the most relevant information
is considered in designing site studies, and that state, local, tribal, and trustee viewpoints are considered
in the remedy selection process. For sites that include waterbodies where TMDLs are being or have
been developed, it is especially important to coordinate site investigations and monitoring or modeling
studies with the state and with EPA's water program. In addition, sharing information early with all
interested parties often leads to quicker and more efficient protection of human health and the
environment through a coordinated cleanup approach.
Superfund's statutory mandate is to ensure that response actions will be protective of human
health and the environment. EPA recognizes, however, that in addition to EPA's response action(s),
restoration activities by the Natural Resource Trustees may be needed. It is important that Superfund
site managers and the Trustees coordinate both the EPA investigations of risk and the Trustee
investigations of resource injuries in order to most efficiently use federal and state resources and to
avoid duplicative efforts.
Additional information on coordinating with Trustees may be found in OSWER Directive
9200.4-22A CERCLA Coordination with Natural Resource Trustees (July 1997), in the 1992
ECO Update The Role of Natural Resource Trustees in the Superfund Process
http:/M^^^epa.gov/superfund/p^ogralTls.'risky''tQolecohtn^i). and in the 1999 OSWER Directive
9285.7-28P Ecological Risk Assessment and Risk Management Principles for Superfund Sites
(also available at the above web site). Additional information on coordinating with states and tribes can
be found in OSWER Directive 9375.3-03P The Plan to Enhance the Role of States and Tribes in
the Superfund Program (httpi/V'vvww.epagov/superfand/states/strole/index.htmy
4. Develop and Refine a Conceptual Site Model that Considers Sediment Stability.
A conceptual site model should identify all known and suspected sources of contamination, the
types of contaminants and affected media, existing and potential exposure pathways, and the known or
potential human and ecological receptors that may be threatened. This information is frequently
summarized in pictorial or graphical form, backed up by site-specific data The conceptual site model
should be prepared early and used to guide site investigations and decision-making. However, it should
be updated periodically whenever new
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information becomes available, and EPA's understanding of ihe site problems increases. In addition, it
frequently can serve as Ihe centerpiece for communication among all stakeholders.
A conceptual site model is especially important at sediment sites because the interrelationship of
soil, surface and groundwater, sediment, and ecological and human receptors is often complex. In
addition, sediments may be subject to erosion or transport by natural or man-made disturbances such
as floods or engineering changes in a waterway. Because sediments may experience temporal, physical.
and chemical changes, it is especially important to understand what contaminants are currently available
to humans and wildlife, and whether this is likely to change in the future under various scenarios. The
risk assessor and project manager, as well as other members of the site team, should communicate
early and often to ensure that they share a common understanding of the site and the basis for the
present and future risks. The May 1998 EPA Guidelines for Ecological Risk Assessment (Federal
Register 63(93) 26846-26924, http:/yv\^w.epa.gov/supertiuid'progranisMsL''tooleco.htiri). the 1997
Superfund Guidance Ecological Risk Assessment Guidance for Superfund: Process for Designing
and Conducting Ecologicql Risk Assessments (EPA 540-R-97-006, also available at the above web
site), and the 1989 Risk Assessment Guidance for Superfund (RAGS), Volume 1, Part A (EPA
540-1-89-002, http://v\'\v\v.epa.sov/supeiibnd/programs/risk-'ragsa^ provide guidance on developing
conceptual site models.
5. Use an Iterative Approach in a Risk-Based Framework.
The NRC report (p. 52) recommends the use of a risk-based framework based on the one
developed by the Presidential/Congressional Commission on Risk Assessment and Risk Management
(PCCRARM, 1997, Framework for Environmental Health Risk Management, Vol. 1, as cited by
NRC 2001). However, as recognized by the NRC (p. 60): "The framework is intended to supplement,
not supplant, the CERCLA remedial process mandated by law for Superfund sites."
Although there is no universally accepted, well-defined risk-based framework or strategy for
remedy evaluation at sediment sites, there is wide-spread agreement that risk assessment should play a
critical role in evaluating options for sediment remediation. The Superfund program uses a flexible,
risk-based framework as part of the CERCLA and NCP process to adequately characterize ecological
and human health site risks. The guidances used by the RCRA Corrective Action program
(Tiitp:/Avvvvv'.epa.gQv/'correci.iveaction./resoiirce/gLiidance) also recommend a flexible risk-based
approach to selecting response actions appropriate for the site.
EPA encourages the use of an iterative approach, especially at complex contaminated sediment
sites. As used here, an iterative approach is defined broadly to include approaches which incorporate
testing of hypotheses and conclusions and foster re-evaluation of site assumptions as new information is
gathered For example, an iterative approach might include pilot testing to determine the effectiveness of
various remedial technologies at a site. As noted in
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the NRC report (p. 66): "Each iteration might provide additional certainty and information to support
further risk-management decisions, or it might require a course correction."
An iterative approach may also incorporate the use of phased, early, or interim actions. At
complex sediment sites, site managers should consider the benefits of phasing the remediation. At some
sites, an early action may be needed to quickly reduce risks or to control the ongoing spread of
contamination. In some cases, it may be appropriate to take an interim action to control a source, or
remove or cap a hot spot, followed by a period of monitoring in order to evaluate the effectiveness of
these interim actions before addressing less contaminated areas.
Hie NRC report makes an important point when it notes (p. 256): "The committee cautions
that the use of the framework or other risk-management approach should not be used to delay a
decision at a site if sufficient information is available to make an informed decision. Particularly in
situations in which there are immediate risks to human health or the ecosystem, waiting until more
information is gathered might result in more harm than making a preliminary decision in the absence of a
complete set of information. The committee emphasizes that a 'wait-and-see' or 'do-nothing' approach
might result in additional or different risks at a site."
6. Carefully Evaluate the Assumptions and Uncertainties Associated with Site
Characterization Data and Site Models.
The uncertainties and limitations of site characterization data, and qualitative or quantitative
models (e.g., hydrodynamic, sediment stability, contaminant fate and transport, or food-chain models)
used to extrapolate site data to future conditions should be carefully evaluated and described. Due to
the complex nature of many large sediment sites, a quantitative model is often used to help estimate and
understand the current and future risks at the site and to predict the efficacy of various remedial
alternatives. The amount of site-specific data required and the complexity' of models used to support
site decisions should depend on the complexity of the site and the significance of the decision (e.g., level
of risk, response cost, community interest). All new models and the calibration of models at large or
complex sites should be peerreviewed consistent with the Agency's peer review process as described
in its Peer Review Handbook (EPA 100-B-OO-OOl, http://www.epa.gov/ORD/spe/2peerrev.hto).
Site managers should clearly describe the basis for all models used and their uncertainties when
using the predicted results to make a site decision. As recognized by the NRC report (p. 65), however,
"Management decisions must be made, even when information is imperfect There are uncertainties
associated with every decision that need to be weighed, evaluated, and communicated to affected
parties. Imperfect knowledge must not become an excuse for not making a decision."
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7. Select Site-specific, Project-specific, and Sediment-specific Risk Management
Approaches that will Achieve Risk-based Goals.
EPA's polity has been and continues to be that there is no presumptive remedy for any
contaminated sediment site, regardless of the contaminant or level of risk. This is consistent with the
NRC report's statement (p. 243) that "There is no presumption of a preferred or default risk
management option that is applicable to all PCB-contaminated-sediment sites." At Superfund sites, for
example., 1he most appropriate remedy should be chosen after considering site-specific data and the
NCP's nine remedy selection criteria All remedies that may potentially meet the removal or remedial
action objectives (e.g., dredging or excavation, in-situ capping, in-situ treatment, monitored natural
recovery) should be evaluated prior to selecting the remedy. This evaluation should be conducted on a
comparable basis, considering all components of the remedies, the temporal and spatial aspects of the
sites, and the overall risk reduction potentially achieved under each option.
At many sites, a combination of options will be the most effective way to manage the risk. For
example, at some sites, the most appropriate remedy may be to dredge high concentrations of
persistent and bioaccumulative contaminants such as PCBs or DDT, to cap areas where dredging is not
practicable or cost-effective, and then to allow natural recovery processes to achieve further recovery
in net depositional areas that are less contaminated.
8. Ensure that Sediment Cleanup Levels are Clearly Tied to Risk Management Goals.
Sediment cleanup levels have often been used as surrogates for actual remediation goals (e.g.,
fish tissue concentrations or other measurable indicators of exposure relating to levels of acceptable
risk). While it is generally more practical to use measures such as contaminant concentrations in
sediment to identify areas to be rdmediated, other measures should be used to ensure that human health
and/or ecological risk reduction goals are being met. Such measures may include direct measurements
of indigenous fish tissue concentrations, estimates of wildlife reproduction, benthic macroinvertebrate
indices, or other "effects endpoints" as identified in the baseline risk assessment.
As noted in the NRC report (p. 123), "The use of measured concentrations of PCBs in fish is
suggested as the most relevant means of measuring exposures of receptors to PCBs in contaminated
sediments." For other contaminants, other measures may be more appropriate. For many sites,
achieving remediation goals, especially for bioaccumulative contaminants in biota, may take many years.
Site monitoring data and new scientific information should be considered in future reviews of 1he site
(e.g., the Superfund five-year review) to ensure that the remedy remains protective of human health and
the environment.
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9. Maximize the Effectiveness of Institutional Controls and Recognize their Limitations.
Institutional controls, such as fish consumption advisories and waterway use restrictions, are
often used as a component of remedial decisions at sediment sites to limit human exposures and to
prevent further spreading of contamination until remedial action objectives are met. While these controls
can be an important component of a sediment remedy, site managers should recognize that they may
not be very effective in eliminating or significantly reducing all exposures. If fish consumption advisories
are relied upon to limit human exposures, it is very important to have public education programs in
place. For other types of institutional controls, other types of compliance assistance programs may also
be needed (e.g., state/local government coordination). Site managers should also recognize that
institutional controls seldom limit ecological exposures. If monitoring data or other site information
indicates that institutional controls are not effective, additional actions may be necessary.
10. Design Remedies to Minimize Short-term Risks while Achieving Long-term
Protection.
The NRC report notes (p. 53) that: "Any decision regarding the specific choice of a risk
management strategy for a contaminated sediment site must be based on careful consideration of the
advantages and disadvantages of available options and a balancing of the various risks, costs, and
benefits associated with each option." Sediment cleanups should be designed to minimize short-term
impacts to the extent practicable, even though some increases in short-term risk may be necessary in
order to achieve a long-lasting solution that is protective. For example, the longterm benefits of
removing or capping sediments containing persistort and bioaccumulative contaminants often outweigh
the additional short-term impacts on the already-affected biota
In addition to considering ihe impacts of each alternative on human health and ecological risks,
the short-term and long-term impacts of each alternative on societal and cultural practices should be
identified and considered, as appropriate. For example, these impacts might include effects on
recreational uses of the waterbody, road traffic, noise and air pollution, commercial fishing, or
disruption of way of life for tribes. At some sites, a comparative analysis of impacts such as these may
be useful in order to fully assess and balance the tradeoffs associated with each alternative.
11. Monitor During and After Sediment Remediation to Assess and Document Remedy
Effectiveness.
A physical, chemical, and/or biological monitoring program should be established for sediment
sites in order to determine if short-term and long-term health and ecological risks are being adequately
mitigated at the site and to evaluate how well all remedial action objectives are being met Monitoring
should normally be conducted during remedy implementation and as long as necessary thereafter to
ensure that all sediment risks have been adequately managed. Baseline
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data needed for interpretation of the monitoring data should be collected during the remedial
investigation.
Depending on the risk management approach selected, monitoring should be conducted during
implementation in order to determine whether the action meets design requirements and sediment
cleanup levels, and to assess the nature and extent of any short-term impacts of remedy implementation.
This information can also be used to modify construction activities to assure that remediation is
proceeding in a safe and effective manner. Long-term monitoring of indicators such as contaminant
concentration reductions in fish tissue should be designed to determine the success of a remedy in
meeting broader remedial action objectives. Monitoring is generally needed to verify the continued
long-term effectiveness of any remedy in protecting human health and the environment and, at some
sites, to verify the continuing performance and structural integrity of barriers to contaminant transport.
IV. IMPLEMENTATION
EPA RPMs, OSCs, and RCRA Corrective Action project managers should immediately begin
to use this guidance at all sites where the risks from contaminated sediment are being investigated. EPA
expects that Federal facility responses conducted under CERCLA or RCRA will also be consistent
with this directive. This consultation process does not apply to Time-Critical or emergency removal
actions or to sites with only sediment-like materials in wastewater lagoons, tanks, storage or
containment facilities, or drainage ditches.
Consultation Process for CERCLA Sites
To help ensure that Regional site managers appropriately consider these principles before
site-specific risk management decisions are made, this directive establishes a two-tiered consultation
procedure that will apply to most contaminated sediment sites. The consultation process applies to all
proposed or listed NPL sites where EPA will sign or concur on the ROD, all Non-Time-Critical
removal actions where EPA will sign or concur on the Action Memorandum, and all "NPL-equivalent"
sites where there is or will be an EPA-enforceable agreement in place.
Tier 1 Process
Where the sediment action(s) for the entire site will address more than 10,000 cubic yards or
five acres of contaminated sediment, Superfund RPMs and OSCs should consult with their appropriate
Office of Emergency and Remedial Response (OERR) Regional Coordinator at least 30 days before
issuing for public comment a Proposed Plan for a remedial action or an Engineering Evaluation/Cost
Analysis (EE/CA) for a Non-Time-Critical removal action.
This consultation entails the submission of the draft proposed plan or draft EE/CA, a written
discussion of how the above 11 principles were considered, and basic site information
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that will assist OERR in tracking significant sediment sites. If the project manager has not received a
response from OERR within two weeks, he or she may assume no further information is needed at this
time. EPA believes that this process will help promote nationally consistent approaches to evaluate,
select and implement protective, scientifically sound, and cost-effective remedies.
Tier 2 Process
This directive also establishes a new technical advisory' group (Contaminated Sediments
Technical Advisory Group-CSTAG) that will monitor the progress of and provide advice regarding a
small number of large, complex, or controversial contaminated sediment Superfund sites. The group will
be comprised often Regional staff and approximately five staff from OSWER, OW, and ORD. For
most sites, the group will meet with the site manager and the site team several times throughout the site
investigation, response selection, and action implementation processes. For new NPL sites, the group
will normally meet within one year after proposed listing. It is anticipated that for most sites, the group
will meet annually until the ROD is signed and thereafter as needed until all remedial action objectives
have been met. The specific areas of assistance or specific documents to be reviewed will be decided
by the group on a case-by-case basis in consultation with the site team. For selected sites with an
on-going RI/FS or EE/CA, the group will be briefed by the site manager some time in 2002 or 2003.
Reviews at sites with remedies also subject to National Remedy Review Board (NRRB) review will be
coordinated with the NRRB in order to eliminate the need for a separate sediment group review at this
stage in the process.
Consultation Process for RCRA Corrective Action Facilities
Generally, for EPA-lead RCRA Corrective Action facilities where a sediment response action is
planned, a two-tiered consultation process will also be used. Where the sediment action(s) for the
entire site will address more than 10,000 cubic yards or five acres of contaminated sediment, project
managers should consult with the Office of Solid Waste's Corrective Action Branch at least 30 days
before issuing a proposed action for public comment This consultation entails the submission of a
written discussion of how the above 11 principles were considered, and basic site information that will
assist OSW in tracking significant sediment sites.
If the project manager has not received a response from OSW within two weeks, he or she
may assume no further information is needed. States are also encouraged to follow these procedures.
For particularly large, complex, or controversial sites, OSW will likely call on the technical advisory
group discussed above.
EPA also recommends that both state and EPA project managers working on sediment
contamination associated with Corrective Action facilities consult with their colleagues in both RCRA
and Superfund to promote consistent and effective cleanups. EPA believes this
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consultation would be particularly important for the larger-scale sediment cleanups mentioned above.
EPA may update this guidance as more information becomes available on topics such as: the
effectiveness of various sediment response alternatives, new methods to evaluate risks, or new methods
for characterizing sediment contamination. For additional information on this guidance, please contact
the OERR Sediments Team Leader (Stephen Ells at 703 603-8822) or the OSW Corrective Action
Programs Branch Chief (Tricia Buzzell at 703 308-8632).
NOTICE: This document provides guidance to EPA Regions concerning how the Agency intends to
exercise its discretion in implementing one aspect of the CERCLA and RCRA remedy selection
process. This guidance is designed to implement national policy on these issues. Some of the statutory
provisions described in this document contain legally binding requirements. However, this document
does not substitute for those provisions or regulations, nor is it a regulation itself. Thus it cannot impose
legally binding requirements on EPA, states, or the regulated community, and may not apply to a
particular situation based upon the circumstances. Any decisions regarding a particular situation will be
made based on the statutes and regulations, and EPA decision-makers retain Ihe discretion to adopt
approaches on a case-by-case basis that differ from this guidance where appropriate. Interested parties
are free to raise questions and objections about the substance of Ihis guidance and the appropriateness
of the application of this guidance to a particular situation, and the Agency welcomes public input on
Ihis document at any time. EPA may change this guidance in the future.
cc: Michael H. Shapiro
Stephen D. Lufu'g
Larry Reed
Elizabeth Cotsworth
Jim Woolford
Jeff Josephson, Superfund Lead Region Coordinator, USEPA Region 2
Carl Daly, RCRA Lead Region Coordinator, USEPA Region 8
Peter Grevatt
NARPM Co-Chairs
OERR Records Manager, IMC 5202G
OERR Documents Coordinator, HOSC 5202G
RCRA Key Contacts, Regions 1-10
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