United States
Environmental Protection
Agency
Off ice of
SolidWwteand
Emergency Response
5EPA
DIRECTIVE NUMBER:
9283.1-03
TITLE: Suggested ROD Language for Various Groundwater
Remediation Options
APPROVAL DATE:
EFFECTIVE DATE:
ORIGINATING OFFICE:
B'flNAL
D DRAFT
STATUS:
REFERENCE (other documents):
OSWER OSWER OSWER
fE DIRECTIVE DIRECTIVE
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United States Environmental Protection Aaencv
Washington. DC 20480
OSWER Directive initiation Request
1. Directive Number
9283.1-03
2. Originator Information
Name of Contact Person
Allison Barry
Mail Cod*
OS-220
Office
HSCD
Telephone Code
8-308^-8366
3. Title
Suggested ROD Language for Various Ground Water Remediation Options
4. Summary of Directive (include bnef statement of purpose) . ~~~
Provides supplementary guidance to 9355.4-03/ "Consideration in Groundwater
Remediation at Superfund Sites" with specific respect to effectiveness of
the 19 groundwater extraction systems currently in operation.
5. Keywords
cleanups; groundwater remediation; technology
6a. Does This Directive Supersede Previous Directiva(s)
b. Does It Supplement Previous Oirtetlve(s)?
n
No
No
I I Yes What directive (number, tftle)
Yes What directive (number, title)
7. Draft Level
A - Signed by AA/DAA
B- Signed by Offict Director | [ C - For Review A Comment | | D - fr Development
8. Document to be distributed to States by Headquarters?
Ye*
x>
No
This Request M««ts OSWER OlreeUvM System Format Standards.
9. Sgnature of Lead Office Directives Coordinator
Betti C. VanEpps, OERR Directives Coordinator
10. Name and Title of Approving Official
Henry L. 'Longest II / Director, QERR
Date
; w
Date
.'• ° f
EPA Form 1316-17 (Rev. S-s7) Previous editions are obsolete.
OSWER OSWER OSWER O
VE DIRECTIVE DIRECTIVE DIRECTIVE
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; J'TED STATES ENVIRONMENTAL PROTf-x
WASHINGTON. D.C. 20460
OCT i 0 1990
OFFICE OF
SOLID WASTE AND EMERGENCY HESPONSE
OSWER Directive 9283.1-03
MEMORANDUM
SUBJECT:
FROM:
TO:
Suggested ROD Language for Various
Remediation Options
Henry L. Longest II, Director
Office of Emergency and Remedi
Bruce M. Diamond, Directq
Office of Waste Programs
ound Water
onse
orcement
Director, Waste Management Division
Regions I, IV, V, VII, VIII
Director, Emergency and Remedial Response Division
Region II
Director,.Hazardous Waste Management Division,
Regions, III, VI, IX
Director, Hazardous Waste Division, Region X
Regional Counsels, Region I - X
Purpose ,
The purpose of this memorandum is to provide supplemental
guidance to the October 18f 1989, OSWER Directive 935S.4-03,
entitled "Considerations in Ground Water Remediation at Superfund
Sites," which examines the role of ground water remediation in
Superfund cleanups and recommends modifications to the current
approach.
Background
A recent study conducted by the Office of Emergency and
Remedial Response (OERR) assessed the effectiveness of nineteen
operating ground water extractions systems in achieving specified
goals. The study found that ground water extraction was
effective in containing contaminant plumes and achieving
significant mass removal of contaminants. However, in many
cases, contaminant concentrations did not decrease linearly over
time to reach desired remediation goals. After significant
initial decreases, concentrations typically leveled off, often at
concentrations higher than the cleanup levels. Factors
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which may explain this phenomenon include the extent of source
removal, hydrogeological characteristics of the aquifer, the
physico-chemical nature of the contaminants, and extraction
system design parameters.
Based on these findings, OSWER recommended consideration of
the following approaches to planning and implementing ground
water remediation: 1) initiation of early or interim response
measures designed to prevent further migration of contaminants
during the remedial investigation, and/or until sufficient
information about system response has been obtained to allow
final remedy selection; 2) provision for changes in the remedy
during implementation in the Record of Decision, either by
specifying a contingency remedy or by selecting an interim remedy
and goal; and 3) collection of additional or supplemental
information with which to better assess contaminant mobility and
system effectiveness, such as data related to vertical changes in
hydraulic conductivity, contaminant partitioning between soil and
ground water, and the presence of non-aqueous phase liquids.
Objective
The objective of this memorandum is to provide suggested
language for Records of Decision corresponding to recommendations
1 and 2 from the OSWER Directive.
Recommended Language
Study findings indicate that it is often difficult to
predict the ultimate concentration to which contaminants in
ground water may be reduced until an extraction system has been
operating for some period.of time. Records of Decision should
reflect the amount of relative uncertainty believed to be
associated with achieving remediation goals in ground water at a
particular site. Corresponding to recommendations 1 and 2 from
OSWER Directive 9355.4-03, RODs may be structured in several ways
to reflect the purpose of a selected remedy: 1) as final actions,
intended to restore ground water quality; 2) as final actions,
with a provision for establishing contingency goals; or 3) as
interim actions, intended to promote plume containment and
generate additional performance data, to be followed by final
decisions. The following standard language may be employed, when
appropriate, to correspond to site-specific remediation
scenarios.
1. FINAL ACTION (low uncertainty/ restoration actions)
In some cases, there may be little uncertainty that the
remedy will be able to achieve the remediation goals specified in
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the ROD throughout the area of attainment. Under these
circumstances, a final remedy, designed to restore the aquifer,
may be specified without a contingency. The following type of
statement should appear in the Selected Remedy section of the
ROD:
The goal of this remedial action is to restore
ground water to its beneficial use, which is, at this
site, (specify whether this is a potential or actual
drinking water source, or used for non-domestic
purposes). Based on information obtained during the
remedial investigation and on a careful analysis of all
remedial alternatives, EPA < (optional) and the
State/Commonwealth of ; > believe that the
selected remedy will achieve this goal. It may become
apparent, during implementation or operation of the
ground water extraction system and its modifications,
that contaminant levels have ceased to decline and are
remaining constant at levels higher than the
remediation goal over some portion of the contaminated
plume. In such a case, the system performance
standards and/or the remedy may be reevaluated.
The selected remedy will include ground water
extraction for an estimated period of years,
during which the system1s performance will be carefully
monitored on a regular basis and adjusted as warranted
by the performance data collected during operation.
Modifications may include any or all of the following:
a) at individual wells where cleanup goals
have been attained, pumping may be
discontinued;
b) alternating pumping at wells to eliminate
stagnation points;
c) pulse pumping to allow aquifer
equilibration and to allow adsorbed
contaminants to partition into ground
water; and
d) installation of additional extraction
wells to facilitate or accelerate cleanup
of the contaminant plume.
To ensure that cleanup goals continue to be
maintained, the aquifer will be monitored at those
wells where pumping has ceased on an occurrence of
every years following discontinuation of ground
water extraction.
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If it is determined that drinking water is not the
beneficial use of the aquifer, as in a Class III aquifer, then
the preceding language should be modified to reflect alternative
uses and remediation goals.
2. CONTINGENCY MEASURES/GOALS (high to moderate uncertainty,
potential ARARs waiver, potential containment goal)
In many cases, information may emerge during implementation
and monitoring of the recovery system which strongly suggests
that it is technically impracticable to restore the aquifer, or
achieve remediation goals throughout the area of attainment
(e.g., in the entire ground water plume; or, if waste is left in
place, the area of the plume excluding the waste management
unit). If it is likely that such information will emerge, the
Region has the option of anticipating future changes in the
Record of Decision by providing for contingency measures. The
BOD should explain those measures in sufficient detail (i.e., in
the Comparative Analysis of Alternatives and Selected Remedy
sections), so that the public has ample opportunity to review and
comment on the contingency as well as the selected remedy. The
Selected Remedy section should also specify the criteria under
which the contingency measures would be implemented.
A. Suggested Language for the Selected Remedy Section of the ROD
The following type of language should appear in the Selected
Remedy portion of the ROD, corresponding to situations in which
it is anticipated that it may be technically impracticable to
reach MCLs/MCLGs or other goals as discussed in the ROD. An
ARARs waiver will be invoked, accompanied by an Explanation of
Significant Difference (ESD), if it is determined, on the basis
of the stated criteria, that MCLs/MCLGs or other ARARs cannot be
achieved within all portions ofathe area of attainment.
The goal of this remedial action is to restore the
ground water to its beneficial use/ which is, at this
site, (specify whether this is a drinking water aquifer
or used for non-domestic purposes). Based on
information obtained during the remedial investigation,
and the analysis of all remedial alternatives, EPA <
(optional) and the State/Commonwealth of >
believe that the selected remedy may be able to achieve
this goal. Ground water contamination may be
especially persistent in the immediate vicinity of the
contaminants1 source, where concentrations are
relatively high. The ability to achieve cleanup goals
at all points throughout the area of attainment, or
plume, cannot be determined until the extraction system
has been implemented, modified as necessary, and plume
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response monitored over time. If the selected remedy cannot
meet the specified remediation goals/ at any or all of the
monitoring points during implementation, the contingency
measures and goals described in this section may replace the
selected remedy and goals for these portions of the plume.
Such contingency measures will/ at a minimum/ prevent
further migration of the plume and include a
combination of containment technologies < typically,
ground water extraction and treatment > and
institutional controls. These measures are considered
to be protective of human health and the environment,
and are technically practicable under the corresponding
circumstances.
The selected remedy will include ground water
extraction for an estimated period of years/
during which time the system's performance will be
carefully monitored on a regular basis and adjusted as
warranted by the performance data collected during
operation. Modifications may include any or all of the
following:
a) at individual wells where cleanup goals have
been attained/ pumping may be discontinued;
b) alternating pumping at wells to eliminate
stagnation points;
c) pulse pumping to allow aquifer
equilibration and encourage adsorbed
contaminants to partition into ground
water; and
d) installation of additional extraction
wells to facilitate or accelerate cleanup
of the contaminant plume.
To ensure that cleanup goals continue to be
maintained/ the aquifer will be monitored at those
wells where pumping has ceased on an occurrence of
every —— years following discontinuation of ground
water extraction.
If, in EPA's judgment, implementation of the selected remedy
clearly demonstrates, in corroboration with strong
hydrogeological and chemical evidence, that it will be
technically impracticable to achieve and maintain remediation
goals in the plume or a portion of the plume, a contingency will
be implemented. For example, a contingency may be invoked when
it has been demonstrated that contaminant levels have ceased to
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decline over time, and have remained constant for a specified
period of time at some statistically significant level above
remediation goals, as verified by multiple monitoring wells.
Where such a contingency situation arises, ground water
extraction and treatment would typically continue as necessary to
achieve mass reduction and remediation, goals throughout the rest
of the area of attainment. The following suggested language
describes the recommended contingency measures:
• ;O • •
If it is determined/ on the basis of the preceding
criteria and the system performance data, that certain
portions of the aquifer cannot be restored to their
beneficial use, all of .the following*measures involving
long-term management may occur, for Ian indefinite
period of time, as a modification of the existing
system: .,..'.. .
a) engineering controls such as physical
barriers, or long-term gradient control
.provided by low level pumping, as containment
measures;
b) chemical-specific ARARs will be waived for
the cleanup of those portions of the
aquifer based on the technical
impracticability of achieving further
contaminant reduction;
c) institutional controls will be
provided/maintained to restrict access to
those portions of the aquifer which remain
' ? above remediation goals.; "; " ;\ ,
d) continued monitoring of specified wells;
and , ,.,,-...•. .>, .•••.-•;.,. :•;, • - -
e) periodic reevaluation of remedial
technologies for ground water restoration.
The decision to invoke any or all of these measures may
be made during a periodic review of the remedial action,
which will occur at • . . " year intervals < at least, every
five years, in accordance with CERCLA section 121 (c) >.
Where the contingency implemented differs significantly from
that described in the ROD, an Explanation of Significant
Differences will be issued or it may be necessary to do a ROD
amendment. Even where the contingency implemented does not
differ significantly from that described in the ROD, it would be
advisable to issue an ESD to inform the public of these actions.
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Where RODs have been issued prior to this guidance, and
information emerges during the implementation and operation of
the ground water extraction system which indicates that
restoration of the aquifer will not be practicable, these RODs
may in some cases have to be amended to accommodate the changes
in goals and remedy design suggested by this document.
i
B. Supporting Language
If a contingency remedy is presented in the ROD, the
preceding language should be accompanied by supporting language
in the Comparative Analysis of Alternatives section of the ROD,
which indicates:
a. that both the primary remedy and the
contingency measures provide overall ;••
protection of human health and the ' . : •"
environment, either by reducing contaminants
to MCLs/MCLGs or other remediation goals, or
through a combination of mass reduction,
institutional and/or engineering controls;
b. that chemical-specific ARARs will either be
attained or waived.
The Statutory Determinations section should establish that
both the selected remedy and the contingency measures fulfill
CERCLA section 121 requirements. In addition, any ARARs waiver
must be justified under the Compliance with ARARs determination.
3. INTERIM ACTIONS (moderate to substantial uncertainty, or
early action containment measures)
Interim actions may be specified under two scenarios: 1) to
prevent further plume migration and initiate cleanup while RI/FS
and post-RI/FS activities are being completed; and 2) to obtain
information about the response of the aquifer to remediation
measures in order to define final cleanup goals that are
practicable for the site. Where there is substantial uncertainty
regarding the ability of a remedy to restore ground water to
drinking water quality (i.e., MCLs/MCLGs) or other beneficial
uses, which could be reduced by further information obtained
during implementation of a remedial action, it will often be
appropriate to select an interim remedial action to prevent
further plume migration and initiate ground water restoration.
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A. Interim Actions
The purpose of the interim action, as discussed in the Scope
and Role of the Operable Unit section, may be to initiate
restoration while additional information is collected to better
assess the practicability of aquifer restoration prior to the
determination of final cleanup levels. Preliminary cleanup
levels may be identified, but this section should emphasize that
while the purpose of the action is to work toward the goal of
restoration, it does not constitute a final action for the ground
water. All interim action RODs should specify, -to the -extent
possible, the period of operation that will occur before a final
decision is made regarding the practicability of aquifer
restoration. At the end of this time, a final action ROD should
be prepared which specifies the final remedy, goals and
timeframe, for the contaminated 'ground water at the site.
An interim action ROD should include the following type of
language in the Selected Remedy section.
This alternative calls for the design and
implementation of an interim remedial action to protect
human health and the environment. The goal(s) of this
remedial action is(are) to (specify interim goals,
e.g., halt the spread of a contaminant plume, remove
contaminant mass, etc.) and to collect data on aquifer
and contaminant response to remediation measures. The
ultimate goal of remediation will be determined in a
final remedial action for this site. This remedial
action will be monitored carefully to determine the
feasibility of achieving this goal with this method and
to ensure that hydraulic control of the contaminated
plume is maintained. After the period of time
necessary/ in EPA's judgment/ to arrive at a final
decision for the site/ a final ROD for ground water/
which specifies the ultimate goal/ remedy and
anticipated remediation timeframe/ will be prepared.
Upon completion of the RI/FS, this interim system may
be incorporated into the design of the site remedy
specified in the final action ROD.
B. Early Interim Actions
As discussed in the National Contingency Plan (NCP) (55 FR
8846, March 8, 1990), EPA is encouraged to initiate interim
actions early in the process, i.e., during the RI/FS. An early
interim action may be used to restrict plume migration until an
RI/FS for a final remedial action is completed. Information
collected during implementation will also be used to evaluate
aquifer response to remediation. This purpose should be
discussed in the Scope and Role of the Operable Unit section.
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Early interim action RODs should not specify final cleanup levels
because such goals are beyond the limited scope of the action.
These will be addressed by the final remedial action ROD.
Both the Early Interim Action and Interim Action options
should be supported by language in the Comparative Analysis of
Alternatives section which indicates that these actions may not
achieve final cleanup levels for the. ground water at the site,
although it is effective in the short term in preventing further
degradation and initiating reduction in toxicity, mobility or
volume. MCLs/MCLGs or state cleanup standards will not be ARARs
for these actions because they are beyond the scope of the
interim action. The nine-criteria evaluation should focus on
those criteria most pertinent to short-term effectiveness and
reduction of toxicity, mobility or volume, consistent with the
scope and purpose of the interim action. In addition, the
Statutory Determinations section should discuss the ways in which
the interim action satisfies the CERCLA section 121 requirements
within the scope of the action (i.e., protectiveness of the
remedy).
Action Requested
Language like that provided in this memorandum should be
incorporated, where appropriate, in Records of Decision which
address contaminated ground water. For additional guidance on
preparing Records of Decision for Superfund sites, please refer
to OSWER Directive 9355.3-02, "Guidance on Preparing Superfund
Decision Documents" (October, 1989).
If you have any questions about this material, please ,;
contact your OERR or OWPE Regional Coordinator, Alison Barry at
FTS 398-8366 or (703) 308-8366, or Jennifer Haley at FTS 398-8363
or (703) 308-8363, in OERR's Hazardous Site Control Division.
?-••-. •...>.
cc: Superfund Branch Chiefs,. Regions I - 'X; '•• .-•-'.
Superfund Section Chiefs, Regions I - X .
NOTICE: The policies set out in this memorandum are intended
solely as guidance. They are not intended, nor can they be
relied upon, to create any right enforceable by any party in
litigation with the United States. EPA officials may decide to
follow the guidance provided in this memorandum, or to act at
variance with the guidance, based on an analysis of specific site
circumstances. The Agency also reserves the right to change this
guidance at any time without public notice. .
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