United States
Environmental Protection
Agency
EPA542-R-13-016
November 2013
Solid Waste and Emergency Response
www.clu-in.org/asr
www.epa.gov/superfund
Superfund Remedy Report
FOURTEENTH EDITION
-------
&EPA
EPA542-R-13-016
November 2013
Solid Waste and Emergency Response
United States
Environmental Protection www.clu-m.org/asr
Agency www.epa.gov/superfund
Superfund Remedy Report
FOURTEENTH EDITION
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Superfund Remedy Report, 14th Edition
Table of Contents
Notice and Disclaimer iii
Acronyms and Abbreviations iv
Executive Summary 1
I. Purpose and Introduction 3
II. Approach 3
III. Use of Treatment at NPL Sites 5
IV. Remedies Selected 6
V. Source Remedies 7
VI. Groundwater Remedies 12
VII. Vapor Intrusion 15
VIILCharacteristics of NPL Sites in the RI/FS Phase 17
IX. Conclusions 20
X. Sources and Electronic Versions 21
AppendixA: Definitions of Selected Remedies A-l
AppendixB: Treatment Technologies Selected by Fiscal Year B-l
Index Index-1
Figures
Figure 1: Total Number of RODs and ROD Amendments per Year (FY 1982-2011) 4
Figure 2: ESDs with Remedy Component Changes Included in Analysis (FY 2005-2011) 4
Figure 3: NPL Sites with Treatment Remedies (FY 1982-2011) 5
Figure 4: Percentage of Decision Documents Addressing Source or Groundwater 6
Figure 5: Remedies Selected in All Decision Documents 6
Figure 6: Types of Remedies in Source Decision Documents (FY 2009-2011) 7
Figure 7: On-site Containment vs. Off-site Disposal (FY 2009-2011) 8
Figure 8: Selection Trends for Source Remedies (FY 1998-2011) 8
Figure 9: Top 6 In Situ Source Treatment Remedies in Decision Documents (FY 2005-2011)....10
Figure 10: Trends in Source Decision Documents Selecting In Situ Treatment (FY 2005-2011). 11
Figure 11: Selection Trends for Groundwater Remedies (FY 1986-2011) 12
Figure 12: Sites with P&T, In Situ Treatment, or MNA Selected as Part of a
Groundwater Remedy 14
Figure 13: Trends in Groundwater Decision Documents Selecting In Situ Treatment
(FY 1986-2011) 15
Figure 14: Most Frequently Occurring Contaminants at OUs in the RI/FS Phase 17
Figure 15: Number of OUs in the RI/FS Phase by Contaminant Group 18
Figure 16: Number of OUs in the RI/FS Phase with Contamination in Selected Media 18
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Superfund Remedy Report, 14th Edition
Tables
Table 1: Source Treatment Technologies Selected in Decision Documents 9
Table 2: Sediment Remedies in Decision Documents (FY 2009-2011) 11
Table 3: Groundwater RemedyTypes Selected in Decision Documents 13
Table 4: In Situ Bioremediation and Chemical Treatment Techniques Selected in Groundwater
Decision Documents (FY 2009-2011) 14
Table 5: Vapor Intrusion Remedies Selected in Decision Documents (FY 2009-2011) 16
Available Electronically
Appendix C: Remedy Selection Summary Matrix FY 2009-11
Appendix D: Source Treatment Technologies Selected in Decision Documents from FY 2009-11,
Organized by Technology
Appendix E: Source Treatment Technologies Selected in Decision Documents from FY 2009-11,
Organized by Location
Appendix F: Sediment Remedies Selected in Decision Documents from FY 2009-11,
Organized by Technology
Appendix G: Sediment Remedies Selected in Decision Documents from FY 2009-11,
Organized by Location
Appendix H: Groundwater Remedies Selected in Decision Documents from FY 2009-11,
Organized by Technology
Appendix I: Groundwater Remedies Selected in Decision Documents from FY 2009-11,
Organized by Location
AppendixJ: Vapor Intrusion Remedies Selected in Decision Documents from FY 2009-11,
Organized by Technology
Appendix K: Vapor Intrusion Remedies Selected in Decision Documents from FY 2009-11,
Organized by Location
Appendix L: Individual Contaminants and Assigned Contaminant Groups in the RI/FS Phase
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Superfund Remedy Report, 14th Edition
Notice and Disclaimer
Preparation of this report has been funded wholly or
in part by the U. S. Environmental Protection Agency
(EPA) under contract number EP-W-07-078. This
report is not intended, nor can it be relied upon, to
create any rights enforceable by any party in litigation
with the United States. Mention of trade names or
commercial products does not constitute endorsement
or recommendation for use. A portable document
format (PDF) version of Superfund'Remedy Report
(SRR) Fourteenth Edition (EPA 542-R-13-016) is
available for viewing or downloading from EPA's
Hazardous Waste Cleanup Information (CLU-IN)
website at www.clu-in.org/asr. For more information
about this report, contact Carlos Pachon
(pachon. carlos@epa.gov) or Linda Fiedler
(fiedler.linda@epa.gov).
November 2013
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Superfund Remedy Report, 14th Edition
Acronyms and Abbreviations
ASD Active soil depressurization
ASR Annual Status Report
AWS Alternative water supply
BTEX Benzene, toluene, ethylbenzene, total
xylenes
CAD Contained aquatic disposal
CERCLA Comprehensive Environmental
Response, Compensation and Liability
Act
CERCLIS Comprehensive Environmental
Response, Compensation and Liability
Information System
CFR Code of Federal Regulations
CLU-IN Hazardous Waste Cleanup Information
COC Contaminant of concern
DNAPL Dense non-aqueous phase liquid
EMNR Enhanced monitored natural recovery
EOU Excess, obsolete, or unserviceable
EPA U. S. Environmental Protection Agency
ERH Electrical Resistance Heating
ESD Explanation of Significant Differences
ET Evapotranspiration
FRTR Federal Remediation Technologies
Roundtable
FY Fiscal year
GAC Granular activated carbon
HRSC High-resolution site characterization
HVAC Heating, ventilation and air
conditioning
1C Institutional control
ISCO In situ chemical oxidation
I SCR In situ chemical reduction
ITRC Interstate Technology 8c Regulatory
Council
LNAPL Light non-aqueous phase liquid
MNA Monitored natural attenuation
MNR Monitored natural recovery
MPE Multi-phase extraction
NA/NFA No action/no further action
NAPL Non-aqueous phase liquid
NCP National Oil and Hazardous
Substances Pollution Contingency Plan
NPL National Priorities List
nZVI Nanoscale zero-valent iron
OB/OD Open burn/open detonation
OSWER Office of Solid Waste and Emergency
Response
OU Operable unit
P&T Pump and treat
PAH Polycyclic aromatic hydrocarbon
PCB Polychlorinated biphenyl
PRB Permeable reactive barrier
PSV Passive soil ventilation
RCRA Resource Conservation and Recovery
Act
RI/FS Remedial Investigation/
Feasibility Study
ROD Record of Decision
S/S Solidification/stabilization
SEE Steam enhanced extraction
SRR Superfund Remedy Report
SSD Sub-slab depressurization
SVE Soil vapor extraction
SVOC Semivolatile organic compound
TCE Trichloroethene
TCH Thermal conduction heating
VEB Vertical engineered barrier
VOC Volatile organic compound
ZVI Zero valent iron
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Superfund Remedy Report, 14th Edition
Executive Summary
The U. S. Environmental Protection Agency (EPA)
prepared the Superfund Remedy Report (SRR) 14^
Edition to provide information and analyses on
remedies selected to address contamination at
Superfund sites. The EPA is particularly interested
in documenting and disseminating information
on innovative treatment technologies that advance
its mission of protecting human health and the
environment at contaminated sites. This report is the
latest in a series, prepared since 1991, on Superfund
remedy selection.
The SRR 14th Edition focuses on the analysis of
Superfund remedial actions from fiscal years (FY)
2009 to 2011. The report includes remedies selected
in 459 decision documents signed in this three-year
period. These documents include 361 Records of
Decision (RODs) and ROD amendments, and 98
Explanations of Significant Differences (ESDs). Only
ESDs that included changes to remedy components
were included in this analysis. The SRR compiles data
on overall remedy selection and on remedies for source
materials (such as soil and sediments), groundwater
and air related to vapor intrusion. The report also
analyzes characteristics of sites under investigation
that do not yet have a decision document.
In the most recent period (FY 2009 to 2011), about
40 percent of all decision documents addressed only
sources, 20 percent addressed only contaminated
groundwater, and 25 percent addressed both. The
remainder included other remedies, such as mitigation
of vapor intrusion or specified no action/no further
action. Treatment, on-site containment, and off-
site disposal of contaminated source media and
groundwater were selected at nearly the same rate
as in the previous timeframe evaluated (FY 2005 to
2008). Overall, remedies included a mix of approaches,
primarily treatment; on-site containment; off-site
disposal; monitored natural attenuation (MNA) or
recovery (MNR); and institutional controls (ICs).
Decision documents selecting only ICs were found
to be for sites that had previous remedial or removal
actions. The more recent remedies often addressed
complex sites involving more than one contaminated
media by selecting remedial strategies with multiple
components to target different site areas, media or
both.
Of the nearly 300 decision documents addressing
source materials, on average Superfund selected
somewhat less treatment, on-site containment and
off-site disposal in FY 2009 to 2011 than in FY
2005 to 2008 (EPA 2010a). In the recent timeframe,
more source decision documents included ICs. The
Superfund remedial program continued to select
treatment for a large number of source remedies.
In situ treatment made up an increasing portion of
selected treatment technologies. On average, half of
recent source treatment decision documents included
in situ treatment. Soil vapor extraction, chemical
treatment, solidification/stabilization (S/S), multi-
phase extraction, bioremediation and in situ thermal
treatment again were the most frequently selected
in situ treatment technologies for sources. Physical
separation, S/S, off-site treatment and recycling
once more were the most common ex situ treatment
methods. Off-site incineration was not selected at all,
versus six during the previous period.
A new feature in the SRR 14th Edition is an analysis
of sediment remedies. Overall, 56 source decision
documents selected a sediment remedy in FY 2009 to
2011. About three-quarters included dredging, off-site
disposal or on-site containment. Some treatment was
also selected (for example, ex situ and in situ S/S and
subaqueous reactive caps). Examples of other remedies
included wetlands restoration or replacement, and
enhanced or monitored natural recovery. Nearly two-
thirds of sediment decision documents included ICs.
Of the 206 groundwater decision documents
evaluated, the recent remedies continue to be a
mix of primarily pump and treat (P&T), in situ
treatment, and MNA, with most also including ICs.
The selection of alternate water supply remedies and
other engineering controls was similar to the previous
timeframe. The number of P&T remedies selected
dropped from an annual average of 21 in FY 2005 to
2008, to an average of 15 in FY 2009 to 2011. MNA
decreased from an average of about 30 per year to 20.
However, the overall percentage selecting either P&T
or MNA decreased only slightly. The selection of in
November 2013
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Superfund Remedy Report, 14th Edition
situ groundwater treatment remedies continued to rise,
averaging almost 40 percent of groundwater decision
documents. Of these, bioremediation and chemical
treatment remained the most frequently selected. The
majority of in situ bioremediation remedies specified
anaerobic bioremediation, and more than half of
chemical treatment remedies were in situ chemical
oxidation. Containment technologies (vertical
engineered barriers such as slurry walls) were selected
at only a few sites.
Since vapor intrusion is being addressed more often in
decision documents, the SRR 14th Edition for the first
time includes an analysis of vapor intrusion mitigation
technologies. Twenty-one FY2009 to 2011 decision
documents addressed vapor intrusion. Sub-slab
depressurization was the most common mitigation
method selected; sealing of openings, sub-membrane
depressurization, vapor barriers, enhanced interior
ventilation and passive ventilation systems were also
selected.
To gain insight on future remedy decisions, this report
contains a summary of the characteristics of over 300
sites with operable units currently in the remedial
investigation and feasibility study (RI/FS) process.
The analysis summarizes preliminary data on the
types of contaminants and affected media at these
sites. The study shows that the majority of sites may
contain contaminated groundwater; over half may
have contaminated soil; and a third, contaminated
sediments. All classes of contaminants (that is, volatile
organic compounds, semivolatile organic compounds,
and inorganic contaminants) may be present at a
large number of these sites. Based on initial data,
polychlorinated biphenyls, lead, trichloroethene,
arsenic, hexavalent chromium and mercury may be
among the most frequently occurring contaminants
addressed in the future.
The remedy and site information provided in this
report can help identify program needs for expanded
technical information. For example, the continued
increase in the selection of in situ groundwater
technologies suggests a role for recently-developed
characterization techniques, such as high-resolution
site characterization (HRSC)1, and thus a need for
more technical resources and support in this area. The
recent selection of vapor intrusion mitigation remedies
also highlights the need for technical information and
support related to vapor intrusion characterization and
mitigation. The preliminary data on sites in the queue
for remedy decisions also provide some indication
of the future demand for remedial technologies,
information of value to stakeholders including
technology developers, consulting and engineering
firms and public entities managing remediation
programs.
1 For further information, please visit the High-Resolution Site Characterization web
page atwww.clu-in.org/hrsc
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Superfund Remedy Report, 14th Edition
I. Purpose and Introduction
The EPA Office of Superfund Remediation and
Technology Innovation prepared this Superfund
Remedy Report, 14th Edition to share analysis of
remediation technologies selected to address
contamination at Superfund sites. The EPA
is particularly interested in documenting and
disseminating information on innovative technologies
that advance its mission of protecting human health
and the environment at contaminated sites.
The information in this report was extracted from
Superfund decision documents. These documents
include RODs, ROD amendments and select ESDs
issued during FY 2009 to 2011. The data build on the
evaluations in 12 editions of Treatment Technologies
for Site Cleanup: Annual Status Report (which covered
the timeframe from FY 1982 through a portion of FY
2005) and SRR13* Edition (which covered FY 2005
to 2008). Remedy data for the most recent period are
compared with previous years to evaluate selection
trends, when appropriate.2
The SRR includes 10 sections.
• Section I discusses the purpose and introduces
the report.
• Section II describes the approach used to collect
and analyze data.
• Section III describes the use of treatment at
National Priorities List (NPL) sites.
• Section IV analyzes types of remedies selected.
• Section V discusses source remedies, including a
breakout of sediment remedies.
• Section VI discusses groundwater remedies.
• Section VII discusses vapor intrusion remedies.
• Section VIII discusses contaminants and media
for sites with planned RODs.
• Section IX presents conclusions.
• Section X lists the data sources and provides
information on how to access the electronic
version of this and previous editions of SRR and
ASR, as well as Appendices C through L that are
only available electronically.
II. Approach
The EPA used data available in the Comprehensive
Environmental Response, Compensation and
Liability Information System (CERCLIS) as of
June 6,2012 and reviews of decision documents to
compile information about remedy selection in the
three-year period between FY 2009 and 2011 (EPA
2012j). Subsequent database or remedy changes are
not reflected in this report. The data used include
remedies selected in decision documents (RODs,
ROD amendments and select ESDs). Only ESDs
with changes to remedy components were included in
the data set. ESDs were not included if they did not
change a remedy component, but instead addressed
another aspect of the remedy, such as quantity of
material to be addressed, contaminants of concern, cost
information, or monitoring requirements.
As of June 6,2012,1,652 sites had been finalized on
the NPL and of those, 359 sites had been deleted.
The report includes only decision documents for these
sites currently final on or deleted from the NPL. The
current analysis does not include decision documents
for non-NPL sites, sites that are proposed for the
NPL or Superfund Alternative approach sites.
Figure 1 depicts the number of RODs and ROD
amendments issued each year through FY 2011.
Figure 2 shows the number of ESDs with changes to
remedy components issued each year from FY 2005 to
2011, the only years for which ESDs were analyzed.
This report evaluates 459 decision documents signed
between FY 2009 and 2011, which includes 361
RODs and ROD amendments, and 98 ESDs.
2 Some data in the ASR reports (FY 1982 to 2004) were compiled on a project-specific basis, rather than a decision-document-specific basis. Projects may have consisted of
many OUs, or just a small portion of one OU, and project data were updated with each edition of the report. Additionally, decision document data are not revised in the SRR
dataset when a decision document is amended. Therefore, it is not always possible to directly compare current data to previous years.
November 2013
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Superfund Remedy Report, 14th Edition
Figure 1: Total Number of RODs and ROD Amendments per Year (FY1982-2011)
O
CC.
O
CC.
o
t_
o>
oo a*, o i—
o o *— *—
o o o o
rxl rxl rxl rxl
40
35
30
25
20
15
10
5
Figure 2: ESDs with Remedy Component Changes
Included in Analysis (FY 2005-2011)
2005 2006 2007 2008 2009 2010 2011
The SRR remedy analysis distinguishes between
remediation of contaminated source materials and
non-source materials such as groundwater. "Source
material" is defined as "material that includes
or contains hazardous substances, pollutants or
contaminants that act as a reservoir for migration
of contamination to ground water [sic], to surface
water, to air, or acts as a source for direct exposure"
(EPA 1991). Source material includes contaminated
soil, sludge, sediment, solid waste, debris, drummed
waste, leachate and any non-aqueous phase liquid
(NAPL) both light (LNAPL) and dense (DNAPL).
Groundwater and surface water remedies are
considered "non-source material" remedies and are
collectively referred to as "groundwater remedies"
in this report. Certain surface water remedies like
drainage and erosion control were grouped with source
containment remedies for the purposes of this report;
they are intended to limit the spread of contamination
from the source medium to the surface water. In this
report, on-site containment and off-site disposal are
often combined as 'containment/disposal.'
All remedies selected in the Superfund remedial
program, including treatment, on-site containment,
off-site disposal and remedial components such
as ICs, are included in this report, with treatment
technologies discussed in more detail. "Treatment
technology means any unit operation or series of unit
operations that alters the composition of a hazardous
substance or pollutant or contaminant through
chemical, biological or physical means so as to reduce
toxicity, mobility or volume of the contaminated
November 2013
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Superfund Remedy Report, 14th Edition
materials being treated."3 Definitions of all remedies
included in this report can be found in Appendix A.
To allow for an analysis of remedy selection trends,
the analysis of FY 2005 to 2008 decision documents
from the SRR 13* Edition was updated to conform
to the technology classification scheme used for this
report. The subcategories of in situ bioremediation
and chemical treatment have been refined. In
addition, the new analysis excludes monitoring as a
remedy, reducing the number of decision documents
counted in the "Other Source Remedies" and "Other
Groundwater Remedies" categories. According to EPA
guidance, "[a]n alternative may include monitoring
only and still be considered 'no action.'" (EPA
1999a).Thus monitoring is not considered itself a
remedy. However, the Superfund program recognizes
the importance of effective monitoring and has
implemented a long-term monitoring optimization
strategy.4 As a result of this update, the FY 2005 to
2008 data presented in SRR 14th Edition may vary
slightly from data for the same period in SRR 13th
Edition. Data before FY 2005 has not been updated.
III. Use of Treatment at NPL Sites
The EPA evaluated the prevalence of treatment at
NPL sites. Of all NPL sites where a remedy has been
selected, 73 percent include at least one treatment
remedy to address contaminated source, groundwater
or both (Figure 3). The EPA's demonstrated preference
for treatment is consistent with CERCLA and the
NCP.5
The data in Figure 3 follow a hierarchy so that each
site is included in only one category. Appendix B
lists the type and number of source and groundwater
treatment technologies selected by fiscal year.
Figure 3: NPL Sites with Treatment Remedies
(FY 1982-2011)
Containment/Disposal
and Other
(391)27%
\
Treatment
(1,077)73%
Treatment of Both
Groundwater and Source
(525) 35%
• Number of sites with remedies =1,468.
• Sites are counted in this figure using the following hierarchy: treatment, non-
treatment, no action/no further action (NA/NFA).
• Sites with treatment remedies include in situ or ex situ treatment, and may also
include non-treatment remedies.
• Sites with only non-treatment remedies do not include treatment remedies in any
decision document. Examples of non-treatment remedies include sediment EMNR,
groundwater MNA, sediment MNR, containment/disposal, ICs and vapor intrusion
components.
• Sites with only NA/NFA do not have treatment or non-treatment remedies selected in
any decision document.
3 CFR, title 40, sec. 300.5
4 For further information, please visit the Optimizing Site Cleanups web page at
www.clu-in.org/optimization
5 USC, title 42, sec. 9621 (b)(1); CFR, title 40, sec. 300.430(a)(1)(iii)(A) and (E); CFR
title 40, sec. 300.430(f)(1)(ii)(E)
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Superfund Remedy Report, 14th Edition
IV. Remedies Selected*
Overall, the percentage of decision documents
addressing sources, groundwater or both remained
relatively constant from the previous reporting period
(Figure 4). Of the 459 decision documents issued FY
2009 to 2011, over 60 percent addressed the source of
contamination and 45 percent addressed contaminated
groundwater. The most prevalent types of remedies
selected were treatment, on-site containment, off-site
disposal and ICs (Figure 5). The remedial program
selected these remedies at nearly the same rate as in
the previous timeframe.
6 A summary of all remedies selected for a particular decision document is available
in Appendix C. Appendix C is available atwww.clu-in.org/asr.
O
o>
en
re
Figure 4: Percentage of Decision Documents
Addressing Source or Groundwater
40%
35%
30%
25%
20%
15%
10%
Both a Source and Source Remedy Groundwater
a Groundwater Remedy Only Remedy Only
^B FY 2005-2008 FY 2009-2011
• Total number of decision documents: 595 (FY 2005-08); 459 (FY 2009-11).
• Decision documents are counted in only one category.
• Decision documents with source and/or groundwater may also have a vapor intrusion
remedy component.
• Vapor intrusion only: data are not available for FY 2005-08; 2% (FY 2009-11).
• NA/NFA only: 18% (FY 2005-08); 14% (FY 2009-11).
Figure 5: Remedies Selected in All Decision Documents
o
70%
50%
30%
20%
Treatment On-site Containment Off-site Disposal MNA,MNR,or ENR ICs
^H FY 2005-2008 FY 2009-2011
Other
NA/NFA only
. Number of decision documents: 595 (FY 2005-08); 459 (FY 2009-11).
• With the exception of NA/NFA only, decision documents may be counted in more
than one category.
• "Other"includes vapor intrusion remedies, wetlands replacement, wetland
restoration and alternative water supplies.
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Superfund Remedy Report, 14th Edition
V. Source Remedies7
As stated above, of the 459 decision documents issued
FY 2009 to 2011, over 60 percent addressed the source
of contamination. Sediments are included in the
analysis of source remedies and are discussed in more
detail on page 11. Recently, more than 50 percent of
decision documents selecting source remedies selected
multiple remedial approaches, including various
combinations of treatment; on-site containment and
off-site disposal; MNR and enhanced monitored
natural recovery (EMNR) (for sediments); and other
remedies, including ICs (Figure 6). Source treatment
was selected in over 40 percent of source documents,
either by itself or in some combination with
containment/disposal and ICs, a value similar with the
previous timeframe (EPA 2010a). An
Appendix D lists the remedy types in decision documents selecting source remedies
from FY 2009 to 2011 by technology, and Appendix E lists by location. Appendix F
lists the remedy types in decision documents selecting sediment remedies from FY
2009 to 2011 by technology, and Appendix G lists by location. Appendices D, E, F
and G are available at www.clu-in.org/asr.
examination of recent decision documents selecting
ICs as the only source remedy found that all were for
sites with previous remedial or removal actions. This
finding is consistent with the NCP, which includes
the expectation that ICs should be used to supplement
engineering controls to prevent or limit exposure.8
In Figure 6, containment/disposal includes both on-
site containment and off-site disposal. On-site source
containment includes primarily cap and cover systems.
Although some waste sent for off-site disposal is
treated prior to disposal, if the treatment is not
specified in the decision document, it is not included
as treatment in this analysis.9
A further analysis of the decision documents selecting
on-site containment, off-site disposal or both showed
their selection frequency is divided into approximately
one-third each (Figure 7).
8 CFR, title 40, sec. 300.430(a)(1)(iii)(D)
9 See CERCLA off-site rule at CFR, title 40, sec. 300.440.
Figure 6: Types of Remedies in Source Decision Documents (FY 2009-2011)
Non-Treatment Remedies
(169)59%
EMNR/MNR & ICs/Other (2)1%
EMNR/MNR,
Containment/Disposal &
ICs/Other(2)1%
ICs or Other
Only (75) 26%
Treatment
Only(23)/
8% /
Treatment & ICs/Other (12) 4%
Treatment &
Containment/Disposal (21) 7%
Treatment Remedies
(119)41%
Treatment,
Containment/Disposal
\& ICs/Other (58) 20%
Containment/Disposal °v
V& ICs/Other (64) 22%
Treatment, EMNR/MNR,
Containment/Disposal & ICs/Other (5) 2%
Containment/Disposal Only (26) 9%
• Number of source decision documents = 288.
• Each decision document is included in only one category.
. EMNR and MNR categories include: EMNR with no MNR (1), MNR with no EMNR (5), both EMNR and MNR (3).
• "ICs or Other Only" includes: ICs (74), wetlands replacement (1).
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Superfund Remedy Report, 14th Edition
Figure 8 shows the trend in the types of source remedies
(treatment, containment/disposal and other) selected in
decision documents over a 14-year period. Other source
remedies are primarily ICs. On average, the selection of
treatment, containment/disposal and ICs has remained
relatively stable over the 14-year period.
Table 1 summarizes the specific types of technologies
selected in source treatment decision documents for
FY 2009 to 2011 and compares that data to FY 2005
to 2008. The table groups in situ technologies, followed
by ex situ. Overall, the selection rate for in situ and
ex situ technologies has remained nearly the same
for the two time periods and are currently 50 and 67
percent, respectively. Recently, the most frequently
selected in situ methods for source were soil vapor
extraction (SVE), chemical treatment (including in
situ chemical oxidation [ISCO] and in situ chemical
reduction [ISCR]), solidification/stabilization (S/S), in
situ thermal treatment, bioremediation and multi-phase
extraction (MPE). Most notably, the selection of in situ
chemical treatment has doubled from 7 to 14 percent.
For the recent timeframe, physical separation is
the most commonly selected ex situ treatment. For
purposes of this report, all types of physical separation
are considered treatment. Physical separation
processes include sifting, sieving and sorting solid
media to separate components, dewatering (including
dewatering of dredged sediment) and decontamination
(for example, cleaning contaminated building
surfaces).
Figure 7: On-site Containment vs. Off-site Disposal
(FY 2009-2011)
Both On-site
Containment and
Off-site Disposal
(63) 36%
On-site Containment
Only (64) 36%
Off-site Disposal
Only (49) 28%
• Number of decision documents selecting containment or disposal = 176.
• Each decision document is counted only once.
Figure 8: Selection Trends for Source Remedies (FY 1998-2011)
90%
•S 80%
o>
g 70%
o
| 60%
'^
H 50%
o>
= 40%
01
en
re
01
Q.
30%
20%
10%
0%
75%
78%
77%
79%
75%
73%
60%
46%
40%
39%
42%
Average Percentages (FY 1998-2011)
Source Treatment ( ): 42%
Source Containment/Disposal ( ): 64%
Other Source Remedies (•): 68%
33%
36%
32%
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Source Treatment
• Number of source decision documents for FY 1998-2011 = 1,293.
Source Containment/Disposal •• Other Source Remedies
• Decision documents may be counted in more than one category.
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Superfund Remedy Report, 14th Edition
Of the 33 FY 2009 to 2011 decision documents that
selected physical separation, 17 selected dewatering,
12 decontamination, and 6 other physical separation
processes such as sieving and mechanical sorting.
Recycling is related to physical separation, and thus
the two are combined.
The selection of ex situ S/S decreased from 19 to
13 percent for the recent time period but is still the
second most commonly chosen ex situ remedial
technology for sources. Solidification and stabilization
are separate processes that are often used together;
however, stabilization does not always result in
solidification. When enough detail was provided in
the decision document, stabilization was categorized
as chemical treatment rather than as S/S for both FY
2005 to 2008 and FY 2009 to 2011 data. Although
usually associated with groundwater, pump and treat
is included in Table 1 as an ex situ source treatment
technology if selected to extract source material, such
as NAPL, leachate or liquid waste.
Table 1: Source Treatment Technologies Selected in Decision Documents
Technology
In SituTreatmen
Total
Y 2005-08)
Percent Source Treatment
Decision Documents Total
(FY 2005-08) (FY 2009-11)
Percent Source Treatment
Decision Documents
(FY 2009-11)
Soil Vapor Extraction
Chemical Treatment
Solidification/Stabilization
Thermal Treatment
Bioremediation
Multi-Phase Extraction
Constructed Treatment Wetland
Subaqueous Reactive Cap
Flushing
Fracturing
Phytoremediation
^^^^^^^^^^^^1
Physical Separation
Solidification/Stabilization
Pump and Treat
Unspecified Off-site Treatment
Recycling
Unspecified On-site Treatment
Phytoremediation
Chemical Treatment
Bioremediation
NAPL Recovery
Thermal Desorption
Unspecified Thermal Treatment
Other Ex Situ Technologies
32
11
14
14
10
6
0
0
2
1
2
31
29
18
11
15
2
0
5
4
1
1
1
13
21% 25
7% 17
9% 11
9% 7
7% 4
4% 3
0% 2
0% 2
1% 1
1% 1
1% 0
21% 33
19% 15
12% 13
7% 11
10% 10
1% 6
0% 5
3% 4
3% 3
1% 1
1% 1
1% 1
9% 0
21%
14%
9%
6%
3%
3%
2%
2%
1%
1%
0%
28%
13%
11%
9%
8%
5%
4%
3%
3%
1%
1%
1%
0%
• Number of source treatment decision documents = 150 (FY 2005-08);
119 (FY 2009-11).
• Decision documents may be included in more than one category.
• For unspecified on-site or off-site treatment, decision document indicates on- or
off-site treatment but does not specify any particular treatment technology.
• "Other Ex Situ Technologies"for FY 2005-08 include air stripping (2); evaporation (1);
incineration - off-site (6); neutralization (1); open burn/open detonation (1); and ex
situ soil vapor extraction (2).
November 2013
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Superfund Remedy Report, 14th Edition
Ex situ incineration was not selected in FY 2009 to
2011, down from 6 selections for off-site incineration
in FY 2005 to 2008. Although off-site disposal may
include incineration, it cannot be included in Table 1
if off-site incineration is not specified in the decision
document.
Figure 9 shows trends over a seven-year period for
the most commonly selected in situ source treatment
remedies. Figure 9 includes percentages as a function
of only in situ source treatment decision documents.
(Table 1 was based on all source treatment, both in
situ and ex situ.) The number of decision documents
selecting in situ treatment averages about 19 per year
for FY 2005 to 2011. Because of the small sample size,
the percentages are heavily dependent on the sites in
the pipeline for that year. For instance, the percentage
increase in SVE in FY 2011 was partially because
one site selected SVE at different operable units in
multiple FY2011 decision documents. Selection
trends tend to vary year to year but for this seven-year
timeframe the types of in situ remedies selected are
fairly consistent. Over the past seven years, the overall
selection of in situ source treatment as a percentage of
all source decision documents has remained stable at
about 20 percent (Figure 10).
Figure 9: Top 6 In Situ Source Treatment Remedies in Decision Documents (FY 2005-2011)
c
E
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o
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c
cu
E
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ra
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^
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^
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70%
60%
50%
40%
30%
20%
10%
0%
61%
47%
50%
01
Q.
2005 2006
Soil Vapor Extraction
Thermal Treatment
2007
2008
2009
Chemical Treatment
Solidification/ Stabilization
2010 2011
Bioremediation
Multi-Phase Extraction
• Number of decision documents selecting in situ source treatment remedies = 131.
• Decision documents may be included in more than one category.
November 2013
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Superfund Remedy Report, 14th Edition
Figure 10: Trends in Source Decision Documents
Selecting In Situ Treatment (FY 2005-2011)
25
20
•- 15
Lrt ' J
o>
&=:
o
Ol
10
0
23%
21%
20%
18%
18%
19%
2005 2006 2007 2008 2009 2010 2011
Number of source decision documents = 645.
Sediment Remedies
Fifty-six source decision documents for FY 2009
to 2011 address sediment (Table 2). Three-quarters
of these decision documents included dredging,
or containment/disposal, while a third selected
treatment. Nearly two-thirds of decision documents
for sediments also included ICs. The term "constructed
treatment wetland" is used to refer to wetlands
constructed for the purposes of treatment. "Wetlands
replacement" refers to wetlands constructed to
compensate for wetlands destroyed by a remedy (such
as placement of a cap in a wetland or other habitat
area). Rehabilitation of a contaminated wetland is
referred to as "wetlands restoration."The S/S remedies
in this table serve to immobilize contaminants in the
sediment prior to disposal.
Table 2: Sediment Remedies in Decision
Documents (FY 2009-2011)
Dewatering
Ex Situ Solidification/
Stabilization
Constructed Treatment Wetland
Subaqueous Reactive Cap
In Situ Solidification/Stabilization
Unspecified On-site Thermal
Treatment
Unspecified On-site Treatment
Enhanced Monitored Natural
Recovery
Monitored Natural Recovery
Dredging, Off-site Disposal and
On-site Containment
Dredging/Excavation
Off-site Disposal
Drainage/Erosion Control
On-site Containment - Upland
Cap or Containment Cell
Subaqueous Non-Reactive Cap
Subaqueous Containment Cell
Stream Realignment
34
20
19
17
6
2
1
Institutional Controls
Wetlands Restoration
Wetlands Replacement
36
10
4
Percent
Sediment
Decision
Documents
29%
4%
2%
2%
61%
36%
34%
30%
11%
4%
7%
• Number of decision documents that address sediment = 83 (56 decision documents
include remedy components and 27 are no action/no further action.)
• Decision documents may be included in more than one category.
November 2013
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Superfund Remedy Report, 14th Edition
VI. Groundwater Remedies10
Of the 459 decision documents from FY 2009 to
2011,45 percent (over 200) addressed groundwater
contamination (Figure 4). The recent remedies
continue to be a mix of primarily P&T, in situ
treatment, MNA and ICs (Figure 11).
The selection of P&T leveled off at about 25 percent
in FY 2005 to 2008 after dropping significantly in the
mid-1990s. From FY 2009 to 2011, P&T selection
has averaged 22 percent of groundwater decision
documents. From FY 2009 to 2011, the selection of
MNA varied from 17 to 35 percent of groundwater
decisions, and is still down significantly from the FY
2005 level of 45 percent. In contrast, the portion of
groundwater decisions that include in situ treatment
has steadily increased since FY 1986; in the most
recent 3 years it rose to an average of 38 percent
from 30 percent in FY 2005 to 2008. Groundwater
containment by vertical engineered barriers (VEBs)
continues to be selected in fewer than 5 percent of
decision documents. Almost all recent groundwater
remedies included other types of groundwater
remedies, primarily ICs. Most (98 percent) of "other
groundwater remedies" in Figure 11 include ICs. Some
of the increase in the selection of 1C remedies may
be attributed to changes in program guidance.11 In
addition, programmatic data reporting used prior to
FY 1998 may have resulted in under reporting of ICs
for those years.
The most frequently selected in situ technologies
continue to be bioremediation, chemical treatment,
air sparging and permeable reactive barriers (PRBs).
The selection rate for these increased slightly in the
recent time period (Table 3). Bioremediation and
chemical treatment made up the majority of in situ
technologies selected from FY 2009 to 2011. Of the
79 groundwater decision documents that selected in
situ treatment, over half included bioremediation and
over a third included chemical treatment.
10 Appendix H lists the remedy types in decision documents selecting groundwater
remedies from FY 2009 to 2011 by technology, and Appendix I lists by location.
Appendices H and I are available at www.clu-in.org/asr.
11 Institutional Controls: A Site Manager's Guide to Identifying, Evaluating and
Selecting Institutional Controls at Superfund and RCRA Corrective Action Cleanups,
EPA 540-F-00-005, OSWER 9355.0-74FS-P, September 2000
Figure 11: Selection Trends for Groundwater Remedies (FY 1986-2011)
100%
g 80%
40%
O
IP 20%
86% 86% 86%
39% 38% 37%
P&T
In Situ Treatment
MNA
Containment (VEB)
Other Groundwater
Remedies (e.g., ICs)
• Number of groundwater decision documents = 1,919.
• Decision documents may be included in more than one category.
• "Other groundwater remedies" include ICs and other remedies not classified as treatment, MNA or containment.
November 2013
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Superfund Remedy Report, 14th Edition
Table 3: Groundwater Remedy Types Selected in Decision Documents
Technologie
Pump and Treat
Groundwater Pump and Treat
Surface Water Collect and Treat
In Situ Treatmen
Bioremediation
Chemical Treatment
Air Sparging
Permeable Reactive Barrier
In-Well Air Stripping
Multi-Phase Extraction
Phytoremediation
Fracturing
MNA of Groundwater
Groundwater Containment (VEB)
Constructed Treatment Wetland
For Groundwater Treatment
For Surface Water Treatment
Institutional Controls
Alternative Water Supply
Engineering Control
Percent
Groundwater
Decision
Documents
FY05-0!
Total
:Y09-11)
OU
38
10
7
0
1
3
1
19%
12%
3%
2%
4y
28
12
8
2
2
0
0
1%
Percent
Groundwater
Decision
Documents
"09-11)
21%
24%
14%
1%
1%
1%
1%
• Number of groundwater decision documents: 322 (FY 2005-08); 206 (FY 2009-11).
• Decision documents may be included in more than one category.
• Engineering Controls for FY 2005-08 include the use of trees for hydraulic gradient control (3) and sewer/sump abandonment (1). Engineering Controls for FY 2009-11 include
water table adjustment (1) and wetlands replacement (1).
The majority of decision documents that selected bioremediation remedies. More than half of decision
bioremediation remedies specified anaerobic documents that selected chemical treatment specified
bioremediation (Table 4). Bioaugmentation (addition I SCO, while a quarter selected I SCR.
of bacteria capable of degrading specific chemicals)
and aerobic bioremediation were also specified in some
November 2013
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Superfund Remedy Report, 14th Edition
Table 4: In Situ Bioremediation and Chemical
Treatment Techniques Selected in Groundwater
Decision Documents (FY 2009-2011)
Technology
Bioremediat'
o o
r\i rN'
18 10
Anaerobic Bioremediation
Bioaugmentation
Aerobic Bioremediation
Cometabolic Treatment
In Situ Chemical Oxidation
In Situ Chemical Reduction
Neutralization
Other In Situ Chemical Treatment
Ozone Sparging
15
4
5
1
__
1
1
1
0
^^_^^^
17
3
1
0
10
5
1
0
1
^^_^^_
9
3
1
0
41
10
7
1
10 28
1
0
2
2
16
7
2
3
3
• Number of decision documents selecting in situ groundwater treatment = 79.
• Decision documents may be included in more than one category.
The last seven years of data were also evaluated to
determine how often multiple remedial components
were selected to address groundwater at a site (Figure
12). For this analysis, remedies are displayed in terms
of sites rather than decision documents, so that for
each time period decisions in multiple documents can
be considered together. For the most recent period,
one third of sites with groundwater remedies include
more than one cleanup approach. In situ treatment
and MNA are the groundwater remedies most often
used together. Of the groundwater remedies used
alone, in situ treatment was selected most frequently,
followed by P&T then MNA. As noted earlier, since
the previous period there was a decrease in sites
selecting P&T, and an overall increase in sites selecting
in situ treatment. Recently, nearly half of sites with
P&T or MNA also include an in situ technology.
Figure 13 shows more clearly the trend in selection
of in situ treatment as a component of groundwater
decision documents since FY 1986.
Figure 12: Sites with P&T, In Situ Treatment, or MNA Selected as Part of a Groundwater Remedy
30%
25%
£ 20%
1
T3
I 15%
10%
o
01
cn
re
o>
Q.
5%
0%
20%
21%
19%
P&T Only P&T and MNA P&T and In Situ In Situ Only P&T, In Situ, In Situ and MNA
(no In Situ) (no MNA) and MNA (no P&T)
^B FY 2005-2008 | FY 2009-2011
. Number of sites with groundwater treatment or MNA: 167 (FY 2005-08); 114 (FY 2009-11).
• Sites are counted only once in this figure as appropriate.
MNA Only
November 2013
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Superfund Remedy Report, 14th Edition
Figure 13: Trends in Groundwater Decision Documents Selecting In Situ Treatment (FY1986-2011)
40%
35%
30%
a 25%
1 20%
39%
38%
37%
15%
| 10%
ra
OOOOOOOOONONONONONONONONONON
OOOOOOOOOOi— i—
oooooooooooo
ON ON ON ON ON ON ON ON ON ON ON ON ON
• Number of groundwater decision documents = 1,919.
VII. Vapor Intrusion12
Data for remedies of air media (including vapor
intrusion) were not included in past versions of the
ASR and SRR. In light of the Superfund program's
recent emphasis on vapor intrusion assessment and
mitigation, vapor intrusion is being addressed more
often in decision documents. The EPA analyzed the
selection of vapor intrusion mitigation technologies for
existing structures.
Vapor intrusion generally occurs when volatile
chemicals migrate from contaminated groundwater
or soil into an overlying building. Volatile chemicals
emit vapors that may migrate through subsurface soils
and into indoor air spaces of overlying buildings in
ways similar to radon gas seeping into homes. Volatile
chemicals may include volatile organic compounds
(VOCs), select semivolatile organic compounds
(SVOCs), some pesticides and some inorganic
analytes, such as elemental mercury and hydrogen
sulfide. Generally, the main concern in buildings has
been that low concentrations of volatile chemicals may
pose an unacceptable health risk to building occupants.
Twenty-one FY 2010 and 2011 decision documents
addressed vapor intrusion (Table 5). Sub-slab
depressurization was the most common mitigation
method selected; sealing of openings, sub-membrane
depressurization, enhanced interior ventilation, vapor
barriers and passive ventilation systems were also
selected. Descriptions of the mitigation technologies
are found in Appendix A. Institutional controls
for vapor intrusion were selected for both existing
and future buildings. In FY 2009, some decision
documents indicated they would monitor for vapor
intrusion and provide mitigation as necessary;
however, a mitigation system was not selected in the
decision document.
12 Appendix J lists the remedy types in decision documents selecting vapor intrusion
remedies from FY 2009 to 2011 by technology, and Appendix K lists by location.
Appendices J and Kare available online atwww.clu-in.org/asr.
November 2013
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Superfund Remedy Report, 14th Edition
Table 5: Vapor Intrusion Remedies Selected in Decision Documents (FY 2009-2011)
Technology
| 2009
2010 |
2011
Total
Vapor Intrusion Mitigation in Existing Structures 0 8 7| 15
Sub-Slab Depressurization
Sealing Cracks and Openings
Sub-Membrane Depressurization
Interior Ventilation
Vapor Intrusion Mitigation (Unspecified)
Passive Barrier (Impermeable Membrane)
Passive Soil Ventilation
Positive Indoor Pressurization
0
0
0
0
0
0
0
0
6
4
4
4
2
0
0
0
6
2
1
0
1
2
1
12
6
5
4
3
2
1
l| 1
Future Construction
Existing Structures
0
0
8
3
9
2
17
5
• Number of decision documents selecting vapor intrusion remedies = 21.
• Decision documents may be included in more than one category.
VIM. Characteristics of NPL Sites in the
RI/FS Phase
Introduction
The EPA recently collected and analyzed available
data on the universe of sites in the Superfund RI/
FS phase to evaluate trends in the types of media and
contaminants that the program will be addressing
in the future. This analysis can help anticipate the
need for certain types of remedial technologies and
site-specific technical assistance. In the past, the EPA
has evaluated the characteristics of Superfund sites
undergoing remedial investigation (RI) or feasibility
studies (FS) to assess the market for remedial
technologies (EPA 2004).
Methodology
This analysis included sites and operable units (OUs)
where an RI/FS had been started but had not been
completed. The analysis is based on sites and OUs
identified in a CERCLIS query conducted on August
24,2011 that identified 670 OUs at 323 sites with RI/
FS actions that had a decision document planned for
FY 2012 or later. The EPA collected data for these
sites from publicly available sources, including site
summaries, NPL factsheets and five-year reviews
when available (if other OUs at the site were already
being addressed). Data were collected about site
contamination, media that may be affected, and classes
of contaminants that may be of concern. For sites with
previous or ongoing cleanup activities, an effort was
made to distinguish areas of the site already addressed,
from those still under investigation. Because at the
time of the analysis, no decision documents had
been signed to address these OUs, the contaminants
and media identified in the current documentation
represent preliminary data on what may be addressed.
Contaminants
The EPA researched contaminant information for
the 670 OUs in the RI/FS phase at the 323 sites.
Contaminant data was found for 535 OUs of the 670
OUs. Of those, specific contaminant information was
available from 447 OUs at 261 sites.
Lead, arsenic, hexavalent chromium, mercury,
cadmium, copper, zinc and nickel were the most
frequently occurring metals for these OUs (Figure
14).Trichloroethene (TCE) and vinyl chloride were
the top VOCs, and polychlorinated biphenyls (PCBs)
were the most frequently occurring SVOCs. PCB
congeners are considered together in this analysis.
November 2013
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Superfund Remedy Report, 14th Edition
Figure 14: Most Frequently Occurring Contaminants at OUs in the RI/FS Phase
35
Polychlorinated Lead Trichloro- Arsenic Hexavalent Mercury Cadmium Vinyl
biphenyls (PCB) ethene chromium chloride
• Total Number of OUs = 447
Benzene Copper Zinc
Tetra- Nickel Penta-
chloroethene chloroethane
The OU contaminants were also evaluated by
commonly-used groups.13 The contaminant groups
used are defined below:
• Metals - Metals; metalloids; explosive metals;
radioactive metals; and organometallic pesticides
and herbicides.
• VOCs - Halogenated VOCs; benzene, toluene,
ethylbenzene, xylene (BTEX); fuels and
distillates; and other nonhalogenated VOCs.
• SVOCs - PCBs; polycyclic aromatic
hydrocarbons (PAHs); organic pesticides
and herbicides; phenols; fuels and distillates;
most explosives; and other halogenated and
nonhalogenated SVOCs.
• Other - nonmetallic inorganics; asbestos; and
unspecified organics or inorganics.
Each contaminant is assigned to only one contaminant
group, and each contaminant group is counted once
per decision document even if it occurs in more than
one medium.
Based on this analysis, metals and VOCs are found at
almost 70 percent of these OUs, and SVOCs at almost
60 percent (Figure 15). More than 60 percent of OUs
were found to have more than one contaminant group.
13 The contaminants included in each contaminant group are listed in Appendix L
(available online at www.clu-in.org/asr).
November 2013
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Superfund Remedy Report, 14th Edition
200
150
-100
o
^
OJ
"I
50
Total Metals:
Total VOCs:
Total SVOCs:
Figure 15: Number of OUs in the RI/FS Phase by Contaminant Group
370 (69%)
359 (67%)
317(59%)
34%
184
VOCs
• Total Number of OUs = 535
Metals SVOCs Metals and Metals and SVOCs and Metals, SVOCs,
SVOCs VOCs VOCs and VOCs
Other
Only
The site summaries often indicated only a general
category of contaminant rather than specific
contaminants because of the preliminary nature of the
data. For example, site summaries noted more than
200 unspecified VOCs, almost 200 unspecified metals,
and almost 100 unspecified PAHs. These data were
included in the contaminant group analysis, but could
not be included in the evaluation of the most frequent
contaminants.
Contaminated Media
The evaluation of contaminated media showed that
nearly 70 percent of OUs in the RI/FS phase may
have contaminated groundwater; almost 60 percent
may have contaminated soil; and more than 30
percent, contaminated sediment (Figure 16). NAPLs
are specifically identified in only one percent of these
OUs, although they may also be present at additional
sites with contaminated groundwater.
400
350
300
2i 250
Figure 16: Number of OUs in the RI/FS Phase
with Contamination in Selected Media
313
01
Q.
O
200
150
100
50
0
Groundwater
Sediment Free-phase
NAPL
Selected Media
• Total Number of OUs = 531
• 4 OUs with contaminant data did not specify media.
November 2013
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Superfund Remedy Report, 14th Edition
IX. Conclusions
The EPA's analysis of remedy selection from FY 2009
to 2011 and a comparison to earlier data shows that
the Superfund remedial program continues to select
treatment at nearly 75 percent of Superfund sites over
the life of the program. The Superfund program also
continues to address complex sites involving multiple
media. In addition, the data show that multiple
technologies are selected to address the same medium,
with each technology targeted at a portion of the
medium or a particular contaminant. In some cases,
the technologies are employed at the same time, while
others are employed in series. Based on the multiple
types of contaminants at the sites and OUs in the RI/
FS phase, future remedies also are likely to include
multiple targeted technologies for a single medium.
The data provided in this report can also help identify
program needs for improved technical information
and support. The successful use of technologies,
particularly in situ methods directed at specific areas
of contamination, is enhanced by the use of more
refined site characterization techniques such as HRSC.
HRSC can provide a greater level of detail about
subsurface conditions before, during and after the
application of subsurface technologies. Therefore the
increase of in situ technology use may suggest a need
for technical support for the application of these site
characterization techniques.
Concerning source remedies:
• The Superfund remedial program continues to
select treatment for a large number of source
remedies.
• Source remedies continue to include a
combination of treatment, containment/disposal
and ICs to address contaminated sites.
• Physical separation was recently selected more
often for ex situ treatment than S/S, although
some chemical stabilization remedies are counted
under chemical treatment.
• SVE, chemical treatment, S/S, bioremediation,
MPE and in situ thermal treatment continue to
be the most frequently selected in situ treatment
technologies.
• On average, half of recent source treatment
decision documents included in situ treatment.
• A wide range of remedies have been selected to
address contaminated sediments. Three-quarters
of the decision documents included dredging or
containment/disposal, and nearly a third included
treatment.
Concerning groundwater remedies in the latest
analysis:
• The selection of P&T and MNA decreased
slightly while the selection of in situ treatment
and ICs has increased.
• Nearly all groundwater decision documents
include ICs. The selection of water supply
remedies and other engineering controls remains
steady.
• The overall selection of in situ bioremediation
and chemical treatment remedies for
groundwater remains steady.
• The majority of in situ bioremediation remedies
specified anaerobic bioremediation. More than
half of the chemical treatment remedies were in
situ chemical oxidation.
• The selection of in situ treatment for
groundwater continues its overall upward trend
and averages 38 percent of decision documents
addressing groundwater.
Concerning vapor intrusion:
• Sub-slab depressurization was the most
frequently selected technology for vapor intrusion
mitigation.
• The more recent selection of vapor intrusion
mitigation remedies highlights the need for
technical information and support related
to vapor intrusion site characterization and
mitigation technologies.
Concerning sites in the RI/FS process:
• Future decision documents will likely continue
to address complex sites with contaminants in
multiple groups (VOCs, metals and SVOCs).
• Groundwater contamination may be addressed
at two-thirds of these sites, soil in more than half
and sediment in about one-third.
• PCBs, lead, TCE, arsenic, hexavalent chromium
and mercury may be among the most frequently
occurring contaminants addressed in the future.
November 2013
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Superfund Remedy Report, 14th Edition
X. Sources and Electronic Versions
This section lists the sources of information used in
this report and provides information on how to access
the electronic version of this report and previous
versions of the ASR and SRR.
Sources
Comprehensive Environmental Response,
Compensation, and Liability (CERCLA), U.S.
Code, title 42, sees. 9601-9675 (2006).
Environmental Protection Agency (EPA). 1991.
A Guide to Principal Threat and Low Level
Threat Wastes. OSWER. November. Publication
9355.3-02FS.
EPA. 1996. A Citizen's Guide to Soil Washing.
OSWER. April. EPA 542-F-96-002.
EPA. 1997. Analysis of Selected Enhancements for
Soil Vapor Extraction. OSWER. September. EPA
542-R-97-007.
EPA. 1998a. Field Applications of In Situ
Remediation Technologies: Ground-Water
Circulation Wells. OSWER.
EPA. 1998b. On-site Incineration: Overview of
Superfund Operating Experience. OSWER.
March. EPA 542-R-97-012.
EPA. 1999a. A Guide to Preparing Superfund
Proposed Plans, Records of Decision, and Other
Remedy Selection Decision Documents (EPA
540-R-98-031). OSWER. July 1999.
EPA. 1999b. Use of Monitored Natural Attenuation
at Superfund, RCRA Corrective Action, and
Underground Storage Tank Sites. OSWER. April
21. OSWER Directive No. 9200.4-17P.
EPA. 2000a. Engineered Approaches to In Situ
Bioremediation of Chlorinated Solvents. OSWER.
July. EPA 542-R-00-008.
EPA. 2000b. Solidification/Stabilization Use at
Superfund Sites. OSWER. September. EPA
542-R-00-010.
EPA. 2004. Cleaning Up the Nation's Waste Sites:
Markets and Technology Trends, 2004 Edition
(EPA 542-R-04-015). OSWER. September 2004.
EPA. 2005. Contaminated Sediment Remediation
Guidance for Hazardous Waste Sites. OSWER.
December. EPA 540-R-05-012.
EPA. 2006. In Situ Treatment Technologies for
Contaminated Soil: Engineering Forum Issue
Paper. OSWER. November. EPA 542-F-06-013.
EPA. 2007. The Use of Soil Amendments for
Remediation, Revitalization, and Reuse. OSWER.
December. EPA 542-R-07-013.
EPA. 2008a. Engineering Issue: Indoor Air Vapor
Intrusion Mitigation Approaches. National
Risk Management Research Laboratory; Office
of Research and Development. October. EPA
600-R-08-115.
EPA. 2008b. Wetlands Compensatory Mitigation.
Office of Wetlands, Oceans and Watersheds. EPA
843-F-08-002.
EPA. 2010a. Superfund Remedy Report (SRR)
Thirteenth Edition (EPA 542-R-10-004). OSWER.
September 2010.
EPA. 2010b. Update on Providing Alternative Water
Supply as Part of Superfund Response Actions.
OSWER. September. OSWER Directive No.
9355.3-22.
EPA. 2011. Fact Sheet on Evapotranspiration Cover
Systems for Waste Containment. OSWER.
February. EPA 542-F-11-001.
EPA. 2012a. A Citizen's Guide to Activated
Carbon Treatment. OSWER. September. EPA
542-F-12-001.
EPA. 2012b. A Citizen's Guide to Air Stripping.
OSWER. September. EPA 542-F-12-002.
EPA. 2012c. A Citizen's Guide to Fracturing for
Site Cleanup. OSWER. September. EPA
542-F-12-008.
EPA. 2012d. A Citizen's Guide to In Situ Chemical
Reduction. OSWER. September. EPA
542-F-12-012.
EPA. 2012e. A Citizen's Guide to Pump and Treat.
OSWER. September. EPA 542-F-12-017.
EPA. 2012f. A Citizen's Guide to Thermal Desorption.
OSWER. September. EPA 542-F-12-020.
November 2013
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Superfund Remedy Report, 14th Edition
EPA. 2012g. A Citizen's Guide to Vapor Intrusion
Mitigation. OSWER. September. EPA
542-F-12-022.
EPA. 2012h. A Citizen's Guide to Vertical
Engineered Barriers. OSWER. September. EPA
542-F-12-022.
EPA. 2012L Assessing Protectiveness at Sites
for Vapor Intrusion: Supplement to the
"Comprehensive Five-Year Review Guidance."
OSWER. November. OSWER Directive No.
9200.2-84.
EPA. 2012j. Comprehensive Environmental Response,
Compensation, and Liability Information System
(CERCLIS). http://cfpub.epa.gov/supercpad/
cursites/srchsites.cfm. This report uses CERCLIS
data as of June 6,2012.
EPA. 2012k. Institutional Controls: A Guide to
Planning, Implementing, Maintaining, and
Enforcing Institutional Controls at Contaminated
Sites. OSWER. December. EPA 540-R-09-011.
EPA. 20121. Superfund Vapor Intrusion FAQs.
OSWER. February 2012. Available at www.epa.
gov/superfund/sites/npl/Vapor Intrusion FAQs
Feb2012.pdf.
EPA. 2013a. CLU-IN Bioremediation Technology
Focus Page [Online], www.clu-in.org. March 8,
2013. www.clu-in.org/techfocus/default.focus/
sec/Bioremediation/cat/Overview.
EPA. 2013b. CLU-IN In Situ Chemical Reduction
Technology Focus Page [Online], www.clu-in.org.
November 18,2013. www.clu-in.org/techfocus/
default.focus/sec/In Situ Chemical Reduction/
cat/Overview/#3
EPA. 2013c. CLU-IN Thermal Treatment: In Situ
Technology Focus Page [Online]. November 18,
2013. www. cluin.org/techfocus/default.focus/sec/
Thermal Treatment%3A In Situ/cat/Overview
Federal Remediation Technologies Roundtable
(FRTR). 2007. Remediation Technologies
Screening Matrix and Reference Guide, 4th
Edition.
Interstate Technology 8c Regulatory Council (ITRC).
1997. Technical and Regulatory Guidelines
for Soil Washing. Metals in Soil Workgroup.
Washington, D.C. December. MIS-1.
ITRC. 2003. Technical and Regulatory Guidance
Document for Constructed Treatment Wetlands.
Wetlands Work Group. Washington, D.C.
December. WTLND-1.
ITRC. 2011. Permeable Reactive Barrier: Technology
Update. Permeable Reactive Barrier Work Group.
Washington, D.C.June. PRB-5-1.
Karn, Barbara; Kuiken,Todd; and Otto, Martha.
2009. Nanotechnology and in Situ Remediation:
A Review of the Benefits and Potential Risks.
Environmental Health Perspectives. December. 12:
Vol. 117. pp. 1823-1831.
U.S. National Archives and Records Administration.
Code of federal regulations (CFR). Title 40.
Protection of Environment. (2006).
Additional Resources
EPA. High-Resolution Site Characterization (HRSC)
Page [Online], www.clu-in.org. February 22,2013.
www.clu-in.org/characterization/technologies/hrsc.
EPA. Optimizing Site Cleanups Page [Online]. June
21,2013. www.clu-in.org/optimization.
FRTR. Federal Remediation Technologies Roundtable
website, www.fi -.gov.
November 2013
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Superfund Remedy Report, 14th Edition
Electronic Versions
SRR 14th edition is available electronically at www.
clu-in.org/asr. The body of the report and its
appendices can be downloaded from the website. In
addition, electronic versions of previous ASR and
SRR reports can also be downloaded. The list below
describes the appendices for the SRR 14th edition.
Appendix A. Definitions of Specific Remedies. This
appendix defines the specific remedies selected as part
of remedial actions.
Appendix B. Treatment Technologies Selected by
Fiscal Year. This appendix lists the ex situ and in situ
source treatment technologies, groundwater in situ
treatment technologies and groundwater pump and
treat remedies selected by fiscal year from 1982 to
2011.
Appendix C. Remedy Selection Summary Matrix FY
2009-11 (only available electronically). This appendix
lists the remedy components selected in each decision
document analyzed for the SRR 14th edition.
Appendix D. Source Treatment Technologies
Selected in Decision Documents from FY
2009-11, Organized by Technology (only available
electronically). This appendix lists the source
treatment technologies selected from FY 2009 to 2011
and the associated sites and operable units.
Appendix E. Source Treatment Technologies
Selected in Decision Documents from FY
2009-11, Organized by Location (only available
electronically). This appendix lists the source
treatment technologies selected from FY 2009 to 2011
and the associated sites and operable units.
Appendix F. Sediment Remedies Selected in
Decision Documents from FY 2009-11, Organized
by Technology (only available electronically). This
appendix lists the sediment remedies selected from
FY 2009 to 2011 and the associated sites and operable
units.
Appendix G. Sediment Remedies Selected in
Decision Documents from FY 2009-11, Organized
by Location (only available electronically). This
appendix lists the sediment remedies selected from
FY 2009 to 2011 and the associated sites and operable
units.
Appendix H. Groundwater Remedies Selected in
Decision Documents from FY 2009-11, Organized
by Technology (only available electronically). This
appendix lists the groundwater technologies selected
in decision documents from FY 2009 to 2011 and the
associated sites and operable units.
Appendix I. Groundwater Remedies Selected in
Decision Documents from FY 2009-11, Organized
by Location (only available electronically). This
appendix lists the groundwater technologies selected
in decision documents from FY 2009 to 2011 and the
associated sites and operable units.
Appendix J. Vapor Intrusion Remedies Selected in
Decision Documents from FY 2009-11, Organized
by Technology (only available electronically). This
appendix lists the vapor intrusion remedies selected
from FY 2009 to 2011 and the associated sites and
operable units.
Appendix K. Vapor Intrusion Remedies Selected in
Decision Documents from FY 2009-11, Organized
by Location (only available electronically). This
appendix lists the vapor intrusion remedies selected
from FY 2009 to 2011 and the associated sites and
operable units.
Appendix L. Individual Contaminants and Assigned
Contaminant Groups in the RI/FS Phase (only
available electronically). This appendix lists the
individual contaminants from data for operable units
in the RI/FS Phase and identifies which contaminant
groups the individual contaminants were assigned.
November 2013
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Superfund Remedy Report, 14th Edition
Appendix A: Definitions of Selected Remedies
Background
The definitions of remedy types provided in this
appendix are based on a review of definitions and lists
of media, remedies, and technologies provided in the
following resources:
• The CERCLA Information System
(CERCLIS3) database
• RODs, ROD amendments, and selected ESDs
for fiscal years (FY) 1982—2011
• The Federal Remediation Technologies
Roundtable (FRTR) Technology Screening
Matrix, Version 4.0
• A Citizens Guide to Remedial Technologies (2012
Editions)
• Other resources.
Definitions Used to Identify Remedy and Media Types
Treatment Technology— "[Any] unit operation or
series of unit operations that alters the composition
of a hazardous substance, pollutant or contaminant
through chemical, biological, or physical means
so as to reduce toxicity, mobility, or volume of the
contaminated materials being treated. Treatment
technologies are an alternative to land disposal of
untreated hazardous wastes without treatment" (CFR,
title 40, sec. 300.5).
Treatment technologies are grouped into eleven
categories. The definitions for four of the categories
below (physical treatment, chemical treatment,
thermal treatment and biological treatment) are based
on definitions provided in the FRTR Technology
Screening Matrix (FRTR 2007). Additional
categories used in this report include Pump and
Treat; Monitored Natural Attenuation (MNA) for
Groundwater; Monitored Natural Recovery (MNR)
for Sediment; Enhanced Monitored Natural Recovery
(EMNR) for Sediment; On-site Containment; Vapor
Intrusion Mitigation; and Other or Unspecified
Remedies.
Source Media — Source media are defined as
"materials] that includes or contains hazardous
substances, pollutants or contaminants that act as a
reservoir for migration of contamination to ground
water, to surface water, to air, or acts as a source for
direct exposure. Contaminated ground water generally
is not considered to be a source material although
nonaqueous phase liquids (NAPLs [occurring
either as residual- or free-phase]) may be viewed as
source materials" (EPA 1991). For purposes of this
report, source media include soil, sediment, sludge,
debris, solid-matrix wastes, NAPLs, equipment,
drums, storage tanks, leachate, landfill gas and any
contaminated media other than groundwater that can
act as a potential source of contamination.
Source Remedy — Any removal, treatment,
containment or management of a contaminant source.
Groundwater Media — One or more aquifers beneath
or proximal to a source medium and contaminated
or potentially contaminated by migration of
contaminants, such as landfill leachate, non-aqueous
phase liquids (NAPL), leaching from soil, etc. Because
groundwater and surface water are both considered
"non-source" media (EPA 1991), for purposes of this
report, surface water remedies are counted along with
groundwater remedies.
Groundwater Remedy — Management of
contaminated groundwater. Groundwater remedies can
include in situ treatment, pump and treat, containment
using vertical engineered barriers, MNA and other
measures to address contaminated groundwater.
Physical Treatment
Physical treatment uses the physical properties of the
contaminants or the contaminated medium to separate
or immobilize the contamination.
Air Sparging "is a process in which air is injected
into the saturated zone below or within the areas
of contamination through a system of wells. As
the injected air rises through the formation, it may
volatilize and remove adsorbed VOC in soils as well
as strip dissolved contaminants from groundwater. Air
sparging is most effective at sites with homogeneous,
high-permeability soils and unconfined aquifers
contaminated with VOCs. SVE is commonly used
with air sparging to capture the volatiles that air
sparging strips from soil and groundwater. The volatile
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Superfund Remedy Report, 14th Edition
contaminants are transported in the vapor phase to the
vadose zone, where they are drawn to extraction wells
and treated using a standard off-gas treatment system"
(EPA 1997). Oxygen added to the contaminated
groundwater and vadose-zone soils also can enhance
biodegradation of contaminants below and above the
water table. The injection of ozone into the aquifer is
referred to as ozone sparging and is a form of chemical
treatment.
Flushing "involves flooding a zone of contamination
with an appropriate solution to remove the
contaminant from the soil. Water or liquid solution is
injected or infiltrated into the area of contamination.
The contaminants are mobilized by solubilization,
formation of emulsions, or a chemical reaction with
the flushing solutions. After passing through the
contamination zone, the contaminant-bearing fluid
is collected and brought to the surface for disposal,
recirculation, or on-site treatment and reinjection....
Flushing solutions may be water, acidic aqueous
solutions, basic solutions, chelating or complexing
agents, reducing agents, cosolvents, or surfactants"
(EPA 2006).
In Situ Geochemical Stabilization — See Chemical
Treatment (for groundwater) or Solidification and
Stabilization (for source media).
In-Well Air Stripping systems "create a circulation
pattern in the aquifer by drawing water into and
pumping it through the wells, and then reintroducing
the water into the aquifer without bringing it above
ground.. ..The well is double-cased with hydraulically
separated upper and lower screened intervals within
the aquifer.. ..The system can be configured with an
upward in-well flow or a downward in-well flow. The
most common configurations involve the injection
of air into the inner casing, decreasing the density of
the groundwater and allowing it to rise.. ..Through
this system, volatile contaminants in the ground
water are transferred from the dissolved phase to the
vapor phase by the rising air bubbles. Contaminated
vapors can be drawn off and treated above ground or
discharged into the vadose zone" (EPA 1998a).
Mechanical Soil Aeration agitates contaminated soil,
using tilling or other means to volatilize contaminants.
Multi-Phase Extraction (MPE) "is an enhancement
of a typical soil vapor extraction (SVE) system that
"involves the removal of contaminated vapors and
groundwater from the same borehole. A vacuum
applied to the borehole extracts contaminated vapors
from unsaturated soils and simultaneously entrains
contaminated groundwater. The groundwater is
subsequently separated from the vapors and treated
using standard aboveground treatment methods.
The groundwater table within the zone of influence
of a [MPE] well is lowered, exposing the capillary
fringe and previously saturated soils to the extraction
vacuum and enabling more effective remediation of
these soils than traditional SVE systems... [MPE]
systems can be implemented to target all phases of
contamination associated with a typical NAPL spill
site. These systems remove residual vadose zone soil
contamination residing in soil gas, dissolved in soil
pore-space moisture, and adsorbed to soil particles.
[MPE] also effectively removes dissolved and free-
phase (both light and dense NAPL [LNAPL and
DNAPL]) contamination in groundwater" (EPA
1997). Dual-phase extraction and bioslurping are
types of MPE.
Physical Separation processes use physical properties
to separate contaminated and uncontaminated
media, or separate different types of media. For
example, different-sized sieves and screens can be
used to separate contaminated soil from relatively
uncontaminated debris. Another application of
physical separation is the dewatering of sediments or
sludge.
Soil Vapor Extraction (SVE) is "used to remove
VOCs from vadose zone soil. Air flow is induced
through contaminated soil by applying a vacuum
to vapor extraction vents and creating a pressure
gradient in the soil. As the soil vapor migrates through
the soil pores toward the extraction vents, VOCs
are volatilized and transported out of subsurface
soil" (EPA 1997). SVE usually is performed in situ;
however, in some cases, it can be used as an ex situ
technology.
Soil Washing "is a process that uses physical and/or
chemical techniques to separate contaminants from
soil and sediments. Contaminants are concentrated
into a much smaller volume of contaminated residue,
which is either recycled or disposed. Washwater can
consist of water only or can include additives such
as acids, bases, surfactants, solvents, chelating or
sequestering agents which are utilized to enhance the
Appendix A: Definitions of Selected Remedies
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Superfund Remedy Report, 14th Edition
separation of contaminants from soils or sediments"
(ITRC 1997). "Hazardous contaminants tend to
bind, chemically or physically, to silt and clay. Silt
and clay, in turn, bind to sand and gravel particles.
The soil washing process separates the contaminated
fine soil (silt and clay) from the coarse soil (sand and
gravel). When completed, the smaller volume of soil,
which contains the majority of the fine silt and clay
particles, can be further treated by other methods
(such as incineration or bioremediation) or disposed of
according to state and federal regulations" (EPA 1996).
Solidification and Stabilization (S/S) reduces the
mobility of hazardous substances and contaminants
in the environment through both physical and
chemical means. "Solidification refers to processes
that encapsulate a waste to form a solid material and
to restrict contaminant migration by decreasing the
surface area exposed to leaching and/or by coating the
waste with low-permeability materials. Solidification
can be accomplished by a chemical reaction between
a waste and binding (solidifying) reagents or by
mechanical processes.. .Examples of inorganic binders
include cement, fly ash, lime, soluble silicates, and
sulfur-based binders, while organic binders include
asphalt, epoxide, polyesters, and polyethylene.
"Stabilization refers to processes that involve chemical
reactions that reduce the leachability of a waste.
Stabilization chemically immobilizes hazardous
materials or reduces their solubility through a chemical
reaction. The physical nature of the waste may or
may not be changed by this process" (EPA 2000b).
Stabilization remedies are classified as S/S whether or
not they ultimately involve solidification.
S/S may be performed either ex situ or in situ. Note
that chemical agents added in situ for the purpose
of binding with contaminants in groundwater (as
opposed to soil) is classified as in situ Chemical
Treatment, not S/S.
Solvent Extraction uses an organic solvent as an
extractant to separate contaminants from soil. The
organic solvent is mixed with contaminated soil in an
extraction unit. The extracted solution then is passed
through a separator, where the contaminants and
extractant are separated from the soil.
Chemical Treatment
Chemical treatment chemically converts hazardous
contaminants to non-hazardous or less toxic
compounds or compounds that are more stable,
less mobile, inert, or all three. Even though a
chemical reaction is not always involved in chemical
precipitation, chemical precipitation is typically
included in this category.
Chemical Fixation or Chemical Stabilization— See
also Solidification and Stabilization.
Chemical Oxidation "typically involves reduction/
oxidation (redox) reactions that chemically convert
hazardous contaminants to nonhazardous or less toxic
compounds that are more stable, less mobile, or inert.
Redox reactions involve the transfer of electrons from
one chemical to another. Specifically, one reactant is
oxidized (loses electrons) and one is reduced (gains
electrons). There are several oxidants capable of
degrading contaminants. Commonly used oxidants
include potassium or sodium permanganate, Fenton's
catalyzed hydrogen peroxide, hydrogen peroxide,
ozone, and sodium persulfate. Each oxidant has
advantages and limitations, and while applicable to soil
contamination and some source zone contamination,
they have been applied primarily toward remediating
groundwater" (EPA 2006). Chemical oxidation can be
conducted either in situ or ex situ.
Chemical Reduction "involves the placement of a
reductant or reductant generating material in the
subsurface for the purpose of degrading toxic organic
compounds to potentially nontoxic or less toxic
compounds, immobilizing metals such as Cr (VI)
by adsorption or precipitation, and degrading non-
metallic oxyanions such as nitrate" (EPA 2013b).
"Common reducing agents include zero valent
metals, which are metals in their pure form. The most
common metal used in [in situ chemical reduction
(ISCR)] is zero valent iron, or 'ZVI.' ...Other
common reducing agents include polysulfides, sodium
dithionite, ferrous iron, and bimetallic materials,
which are made up of two different metals. The most
common bimetallic material used in ISCR is iron
coated with a thin layer of palladium or silver" (EPA
2012d).
Appendix A: Definitions of Selected Remedies
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Superfund Remedy Report, 14th Edition
In Situ Chemical Oxidation (ISCO) — See Chemical
Oxidation.
In Situ Chemical Reduction (ISCR)— See Chemical
Reduction.
Nanoremediation "methods entail the application
of reactive nanomaterials for transformation and
detoxification of pollutants. These nanomaterials
have properties that enable both chemical reduction
and catalysis to mitigate the pollutants of concern....
Because of their minute size and innovative surface
coatings, nanoparticles may be able to pervade very
small spaces in the subsurface and remain suspended
in groundwater, allowing the particles to travel farther
than larger, macro-sized particles and achieve wider
distribution....
"Many different nanoscale materials have been
explored for remediation....Of these, nanoscale
zero-valent iron (nZVI) is currently the most
widely used.... nZVI particles range from 10 to 100
[nanometers (nm)] in diameter The high reactivity
of nZVI particles is in part a direct result of their
high specific surface area.. ..nZVTs small particle size
also allows more of the material to penetrate into soil
pores, and it can be more easily injected into shallow
and deep aquifers, a property that is particularly
beneficial when contamination lies underneath a
building" (Karn, Kuiken, & Otto 2009).
Neutralization is a chemical reaction between an
acid and a base. The reaction involves acidic or caustic
wastes that are neutralized (pH is adjusted toward 7.0)
using caustic or acid additives.
Permeable Reactive Barriers (PRB) are "in situ,
permeable treatment zone[s] designed to intercept
and remediate a contaminant plume. The term 'barrier'
is intended to convey the idea that contaminant
migration is impeded; however, the PRB is designed
to be more permeable than the surrounding aquifer
media so that groundwater can easily flow through the
structure without significantly altering groundwater
hydrology. The treatment zone may be created directly
using reactive materials such as zero-valent iron (ZVI),
or indirectly using materials designed to stimulate
secondary processes (e.g., adding carbon substrate and
nutrients to enhance microbial activity). In this way,
contaminant treatment may occur through physical,
chemical, or biological processes" (ITRC 2011).
Subaqueous Reactive Cap refers to an underwater
cover in which "[specialized] materials [are] used to
enhance the chemical isolation capacity...compared
to sand caps. Examples include...reactive/adsorptive
materials such as activated carbon, apatite, coke,
organoclay, zero-valent iron and zeolite. Composite
geotextile mats containing one or more of these
materials (i.e., reactive core mats) are becoming
available commercially" (EPA 2005).
Biological Treatment
Biological treatment involves adding or stimulating
the growth of microorganisms, which metabolize
contaminants or create conditions under which
contaminants will chemically convert to non-
hazardous or less toxic compounds or compounds
that are more stable, less mobile, and/or inert.
Phytoremediation, the use of plants to remove,
stabilize, or destroy contaminants, is included in the
definition of biological treatment.
Bioaugmentation is "[the] addition of microbes to the
subsurface where organisms able to degrade specific
contaminants are deficient. Microbes may be 'seeded'
from populations already present at a site and grown
in aboveground reactors or from specially cultivated
strains of bacteria having known capabilities to
degrade specific contaminants" (EPA 2000a).
Bioremediation "uses microorganisms to degrade
organic contaminants in soil, groundwater, sludge, and
solids. The microorganisms break down contaminants
by using them as an energy source or cometabolizing
them with an energy source. More specifically,
bioremediation involves the production of energy in a
redox reaction within microbial cells. These reactions
include respiration and other biological functions
needed for cell maintenance and reproduction. A
delivery system that provides one or more of the
following is generally required: an energy source
(electron donor), an electron acceptor, and nutrients"
(EPA 2013a).
Constructed Treatment Wetlands are "manmade
wetlands built to remove various types of pollutants
that may be present in water that flows through them.
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Superfund Remedy Report, 14th Edition
They are constructed to recreate, to the extent possible,
the structure and function of natural wetlands.. .They
possess a rich microbial community in the sediment
to effect the biochemical transformation of pollutants,
they are biologically productive, and.. .they are self-
sustaining. . ..[Constructed wetlands] utilize many of
the mechanisms of phytoremediation" (ITRC 2003).
Note that the term "constructed wetlands" is used to
refer only to wetlands constructed for the purposes
of treatment, and not to wetlands constructed to
compensate for wetlands destroyed by a remedy (such
as placement of a cap in a marsh). Such "compensatory
wetlands" are counted as "Wetlands Replacement."
Phytoremediation "uses [macroscopic] plants
to extract, degrade, contain, or immobilize
contaminants in soil, groundwater, and other
contaminated media. The phytoremediation
mechanisms used to treat contaminated [media].. .are
phytoextraction, rhizodegradation, phytodegradation,
phytovolatilization, and phytostabilization" (EPA
2006). Phytoremediation may be applied in situ or ex
situ.
Note that while phytoremediation may include the
use of microorganisms in conjunction with plants,
it is distinguished from bioremediation in that
bioremediation does not use macroscopic plants or
trees. For purposes of this report, the use of plants
to control surface water drainage, to influence
groundwater movement, or to adjust the water table
are not considered phytoremediation. Such remedies
are classified as engineering controls.
Thermal Treatment
Thermal treatment uses heat to separate contaminants
from contaminated media by increasing their mobility.
Thermal treatment includes volatility; destroying
contaminants or contaminated media by burning,
decomposing, or detonating the contaminants or the
contaminated media; or immobilizing contaminants by
melting and solidifying the contaminated media.
Electrical Resistance Heating (ERH) "uses arrays of
electrodes installed around a central neutral electrode
to create a concentrated flow of current toward the
central point. Resistance to flow in the soils generates
heat greater than 100°C, producing steam and readily
mobile contaminants that are recovered via vacuum
extraction and processed at the surface. Electrical
resistance heating is an extremely rapid form of
remediation with case studies of effective treatment of
soil and groundwater in less than 40 days. Three-phase
heating and six-phase soil heating are varieties of this
technology" (EPA 2013c). ERH is a type of In Situ
Thermal Treatment.
Incineration "uses controlled flame combustion to
volatilize and destroy organic contaminants and is used
to treat a variety of media, including soils, sludges,
liquids, and gases. An incinerator consists of a burner,
which ignites the supplied fuel and combustibles in
the waste feed in a combustion chamber. Efficiency
of combustion depends on three main factors of the
combustion chamber: temperature, residence time
of the waste material in the combustion chamber,
and turbulent mixing of the waste material. Thermal
destruction of most organic compounds occurs at
temperatures between 1,100°F and 1,200°F. The
majority of hazardous waste incinerators are operated
at temperatures that range from 1,200°F to 3,000°F in
the burning zone" (EPA 1998b). On-site incineration
typically uses a transportable unit; for off-site
incineration, waste is transported to a central facility.
In Situ Thermal Treatment (also referred to as
thermally-enhanced SVE) consists of "different
methods and combinations of techniques to apply
heat to polluted soil and/or groundwater in situ.
The heat can destroy or volatilize organic chemicals.
As the chemicals change into gases, their mobility
increases, and the gases can be extracted via collection
wells for capture and cleanup in an ex situ treatment
unit. Thermal methods can be particularly useful for
dense or light nonaqueous phase liquids (DNAPLs
or LNAPLs)" (EPA 2013c). Specific types of in situ
thermal treatment techniques include conductive
heating, electrical resistive heating, radio frequency
heating, hot air injection, hot water injection, and
steam enhanced extraction.
In Situ Thermal Desorption — See Thermal
Conduction Heating (TCH).
Open Burn (OB) and Open Detonation (OD)
operations "are conducted to destroy excess, obsolete,
or unserviceable (EOU) munitions and energetic
materials. In OB operations, energetics or munitions
are destroyed by self-sustained combustion, which is
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Superfund Remedy Report, 14th Edition
ignited by an external source, such as a flame, heat, or
a detonation wave.. .In OD operations, detonatable
explosives and munitions are destroyed by detonation,
which is generally initiated by the detonation of an
energetic charge" (FRTR 2007).
Steam Enhanced Extraction (SEE) "heats the
soil and groundwater and enhances the release of
contaminants from the soil matrix by decreasing
viscosity and accelerating volatilization. Steam
injection may also destroy some contaminants. As
steam is injected through a series of wells within and
around a source area, the steam zone grows radially
around each injection well. The steam front drives the
contamination to a system of ground-water pumping
wells in the saturated zone and soil vapor extraction
wells in the vadose zone" (EPA 2013c). SEE is a type
of In Situ Thermal Treatment.
Thermal Conduction Heating (TCH) "(also referred
to as electrical conductive heating or in situ thermal
desorption) supplies heat to the soil through steel
wells or with a blanket that covers the ground surface.
As the polluted area is heated, the contaminants are
destroyed or evaporated. Steel wells are used when
the polluted soil is deep. The blanket is used where
the polluted soil is shallow. Typically, a carrier gas or
vacuum system transports the volatilized water and
organics to a treatment system" (EPA 2013c). TCH is
a type of In Situ Thermal Treatment.
Thermal Desorption "removes organic contaminants
from soil, sludge or sediment by heating them ... to
evaporate the contaminants. Evaporation changes the
contaminants into vapors (gases) and separates them
from the solid material Thermal desorption involves
excavating soil or other contaminated material for
treatment in a thermal desorber. The desorber may
be assembled at the site for onsite treatment, or the
material may be loaded into trucks and transported
to an offsite thermal desorption facility. To prepare
the soil for treatment, large rocks or debris first must
be removed or crushed.. ..If the material is very
wet, the water may need to be removed to improve
treatment....
"The prepared soil is placed in the thermal desorber
to be heated. Low-temperature thermal desorption is
used to heat the solid material to 200-600°F [90 to
320°C] to treat VOCs. If SVOCs are present, then
high-temperature thermal desorption is used to heat
the soil to 600-1000°F [320 to 540°C].
"Gas collection equipment captures the contaminated
vapors. Vapors often require further treatment,
such as removing dust particles. The remaining
organic vapors are usually destroyed using a thermal
oxidizer, which heats the vapors to temperatures high
enough to convert them to carbon dioxide and water
vapor.. ."(EPA 2012f). Thermal desorption is an ex situ
treatment process. In situ thermal desorption processes
are discussed above as In Situ Thermal Treatment.
Thermally-Enhanced SVE— See In Situ Thermal
Treatment.
Vitrification is a thermal treatment process that
converts contaminated soil to stable glass and
crystalline solids. There are two methods for producing
heat for melting the contaminated soil. The older
method uses electrodes and electrical resistance to
vitrify materials, while the emerging technique uses
plasma arc technology.
"In the electrical resistance method, high voltage is
applied to electrodes (typically four) placed in the
soil. Starter frit (generally graphite) is placed on the
soil surface and electrical current heats the soil from
the top down to temperatures between 1,400 and
2,000°C [2,550 to 3,650°F].... If the silica content of
the soil is sufficiently high, contaminated soil can be
converted into glass. Heating vaporizes or pyrolyzes
organic contaminants. Most inorganic contaminants
are encased in the glass-like monolith that results
when the soil cools after treatment" (EPA 2006).
Vitrification may be conducted in situ or ex situ.
Pump and Treat
Pump and treat (P&T) "is a common method for
cleaning up groundwater [and other aqueous media]
contaminated with dissolved chemicals, including
industrial solvents, metals, and fuel oil. [Water is
extracted and conveyed] to an above-ground treatment
system that removes [or destroys/converts] the
contaminants. Pump and treat systems also are used to
'contain' the contaminant plume. Containment of the
plume keeps [the plume] from spreading by pumping
contaminated water toward the wells. This pumping
helps keep contaminants from reaching drinking water
Appendix A: Definitions of Selected Remedies
A-6
-------
Superfund Remedy Report, 14th Edition
wells, wetlands, streams, and other natural resources"
(EPA 2012e). For the purpose of this report, all P&T
systems are considered treatment, even if designed
to only contain, rather than restore, a contaminated
plume. Also for the purposes of this report, surface
water P&T-like remedies, such as collection and
treatment of a local creek or stream that receives mine-
influenced wastewater, were counted with groundwater
P&T.
• Activated Carbon Treatment — "Activated carbon
is a material used to filter harmful chemicals from
contaminated water and air. It is composed of
black granules of coal, wood, nutshells or other
carbon-rich materials....Granular activated carbon
or 'GAC' can treat a wide range of contaminant
vapors including radon and contaminants
dissolved in groundwater, such as fuel oil, solvents,
polychlorinated biphenyls (PCBs), dioxins, and
other industrial chemicals, as well as radon and
other radioactive materials. It even removes low
levels of some types of metals from groundwater.
"Activated carbon treatment generally consists of
one or more columns or tanks filled with GAC.
Contaminated water or vapors are usually pumped
through a column from the top down, but upward
flow is possible. As the contaminated water or air
flows through the GAC, the contaminants sorb to
the outer and inner surfaces of the granules....
"The GAC will need to be replaced when the
available surfaces on the granules are taken up by
contaminants and additional contaminants can
no longer sorb to them [sufficiently to prevent
breakthrough of contaminants at concentrations
that exceed the designed discharge standard
for the GAC system].The 'spent'GAC may
be replaced with fresh GAC or 'regenerated' to
remove the sorbed contaminants" (EPA 2012a).
GAC can be regenerated on site or off site using
steam.
• Air Stripping "is the process of moving air through
contaminated groundwater or surface water in an
above-ground treatment system....
"Air stripping uses either an air stripper or aeration
tank to force air through contaminated water and
evaporate VOCs. The most common type of air
stripper is a packed-column air stripper, which
is a tall tank filled with pieces of plastic, steel, or
ceramic packing material.
"Contaminated water is pumped above ground
and into the top of the tank and sprayed over the
top of the packing material. The water trickles
downward through the spaces between the
packing material, forming a thin film of water that
increases its exposure to air blown in at the bottom
of the tank. A sieve-tray air stripper is similar in
design but contains [numerous] trays with small
holes. As water flows across the trays, a fan at
the bottom blows air upwards through the holes,
increasing air exposure. Aeration tanks are another
type of design that remove VOCs by bubbling air
into a tank of contaminated water" (EPA 2012b).
Filtration "is the physical process of mechanical
separation based on particle size whereby particles
suspended in a fluid are separated by forcing the
fluid through a porous medium. As fluid passes
through the medium, the suspended particles
are trapped on the surface of the medium and/or
within the body of the medium. Ultrafiltration/
microfiltration occurs when particles are separated
by forcing fluid through a semipermeable
membrane. Only the particles whose size are
smaller than the openings of the membrane are
allowed to flow through" (FRTR 2007). Other
filtration methods include nanofiltration and
reverse osmosis.
Ion Exchange "removes ions from the aqueous
phase by the exchange of cations or anions
between the contaminants and the exchange
medium. Ion exchange materials may consist
of resins made from synthetic organic materials
that contain ionic functional groups to which
exchangeable ions are attached. They also may be
inorganic and natural polymeric materials. After
the resin capacity has been exhausted, resins can be
regenerated for re-use" (FRTR 2007).
Metals Precipitation "from contaminated water
involves the conversion of soluble heavy metal
salts to insoluble salts that will precipitate. The
precipitate can then be removed from the treated
water by physical methods such as clarification
(settling) and/or filtration. The process usually uses
Appendix A: Definitions of Selected Remedies
A-7
-------
Superfund Remedy Report, 14th Edition
pH adjustment, addition of a chemical precipitant, remain in sediment are not easily transformed or
and flocculation. Typically, metals precipitate from destroyed. For this reason, risk reduction due to
the solution as hydroxides, sulfides, or carbonates. natural burial through sedimentation is more common
The solubilities of the specific metal contaminants and can be an acceptable sediment management
and the required cleanup standards will dictate the option. Dispersion is the least preferable basis for
process used. In some cases, process design will remedy selection based on MNR. While dispersion
allow for the generation of sludges that can be sent may reduce risk in the source area, it generally
to recyclers for metal recovery" (FRTR 2007). increases exposure to contaminants and may result
in unacceptable risks to downstream areas or other
Monitored Natural Attenuation receiving water bodies....
(MNA) for Groundwater «The key difference between MNA for ground
Groundwater MNA is "the reliance on natural water and MNR for sediment is in the type of
attenuation processes (within the context of a carefully processes most often being relied upon to reduce
controlled and monitored site cleanup approach) to risk. Transformation of contaminants is usually the
achieve site-specific remediation objectives within major attenuating process for contaminated ground
a timeframe that is reasonable compared to that water; however, these processes are frequently too
offered by other more active methods. The 'natural slow for the persistent contaminants of concern
attenuation processes' that are at work in such a (COCs) in sediment to provide for remediation in a
remediation approach include a variety of physical, reasonable timeframe. Therefore, isolation and mixing
chemical, or biological processes that, under favorable of contaminants through natural sedimentation is the
conditions, act without human intervention to reduce process most frequently relied upon for contaminated
the mass, toxicity, mobility, volume, or concentration sediment" (EPA 2005).
of contaminants in soil or groundwater. These in
situ processes include biodegradation; dispersion; Enhanced Monitored Natural
dilution; sorption; volatilization; radioactive decay; and Recovery (EMNR) for Sediment
chemical or biological stabilization, transformation, or Natoal r£ combined with an engineering
destruction of contaminants. When relying on natural h -s c^ed Enhanced Monitored Natural
attenuation processes for site remediation, EPA prefers «T <, 1
, 1111 . Recovery. In some areas, natural recovery may appear
those processes that degrade or destroy contaminants. ... u ^u" *, • *. j ^ ^u ^ r
. . £_,. 5 , ,„/. „ , to be the most appropriate remedy, yet the rate of
Also, EPA generally expects that MNA will only ,. ... +L + i • • ffi • +
' r i 1 /r sedimentation or other natural processes is insufficient
be appropriate for sites that have a low potential for tQ reduce ^ within an table timeframe.
contaminant migration (EPA 1999b). Where ^ -s ^ c^ project managerg may consider
11 •*. j KI *. m /i»in\ t r j- * accelerating the recovery process by engineering
Monitored Natural Recovery (MNR) for Sediment f 6 « , .{/ ,,... y f*.,. « 6 f
' means, tor example by the addition of a thin layer of
Sediment MNR "[relies] on a wide range of naturally clean sediment. This approach is sometimes referred
occurring processes to reduce risk [from contaminated to as 'thin-layer placement' or 'particle broadcasting.'
sediments] to human and/or ecological receptors. Thin-layer placement normally accelerates natural
These processes may include physical, biological, and recovery by adding a layer of clean sediment over
chemical mechanisms that act together to reduce the contaminated sediment. The acceleration can occur
risk posed by the contaminants Natural processes through several processes, including increased dilution
that reduce toxicity through transformation or through bioturbation of clean sediment mixed with
reduce bioavailability through increased sorption are underlying contaminants. Thin-layer placement is
usually preferable as a basis for remedy selection to typically different than.. .isolation caps.. .because
mechanisms that reduce exposure through natural it is not designed to provide long-term isolation
burial or mixing-in-place because the destructive/ of contaminants from benthic organisms. While
sorptive mechanisms generally have a higher degree thickness of an isolation cap can range up to several
of permanence. However, many contaminants that feet, the thickness of the material used in thin layer
Appendix A: Definitions of Selected Remedies A-8
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Superfund Remedy Report, 14th Edition
placement could be as little as a few inches.. ..Clean
sediment can be placed in a uniform thin layer over
the contaminated area or it can be placed in berms
or windrows, allowing natural sediment transport
processes to distribute the clean sediment to the
desired areas.
"Project managers might also consider the addition
of flow control structures to enhance deposition in
certain areas of a site" (EPA 2005).
Note that a layer of clean sediment placed as backfill
following dredging or excavation is not considered
EMNR.
On-Site Containment Technologies
For the purpose of this report, on-site containment
includes several containment technologies, including
caps, covers, and vertical engineered barriers (VEBs).
Caps and Cover Systems consist of surface barriers
composed of one of more layers of impermeable
material designed to contain contaminated source
material. Cover systems can be used to prevent direct
contact with the source material or minimize leachate
creation by preventing surface water infiltration into
the contained source material.
Evapotranspiration (ET) Covers are alternatives to
conventional cap and cover systems. "ET cover systems
are designed to rely on the ability of a soil layer to
store the precipitation until it is naturally evaporated
or is transpired by the vegetative cover. In this respect
they differ from more conventional cover designs
in that they rely on obtaining an appropriate water
storage capacity in the soil rather than...engineered
low hydraulic conductivity [barrier components].
ET cover system designs are based on using the
hydrological processes (water balance components) at
a site, which include the water storage capacity of the
soil, precipitation, surface runoff, evapotranspiration,
and infiltration. The greater the storage capacity
and evapotranspirative properties are, the lower the
potential for percolation through the cover system"
(EPA 2011).
Subaqueous Containment Cell (Contained Aquatic
Disposal [CAD]) "is a type of subaqueous capping
in which the dredged sediment is placed into a
natural or excavated depression elsewhere in the
water body. A related form of disposal, known as
level bottom capping, places the dredged sediment
on a level bottom elsewhere in the water body,
where it is capped. [CAD] has been used for
navigational dredging projects (e.g., Boston Harbor,
Providence River), but has been rarely considered for
environmental dredging projects. However, there may
be instances when neither dredging with land disposal
nor capping contaminated sediment in-situ is feasible,
and it may be appropriate to evaluate CADs. The
depression used in the case of a CAD should provide
lateral containment of the contaminated material,
and also should have the advantage of requiring less
maintenance and being more resistant to erosion than
level-bottom capping" (EPA 2005).
Subaqueous Non-Reactive Cap refers to "the
placement of a subaqueous covering or cap of clean
material over contaminated sediment that remains
in place. Caps are generally constructed of granular
material, such as clean sediment, sand, or gravel" (EPA
2005).
Vertical Engineered Barriers (VEB) are "[walls] built
below ground to control the flow of groundwater.
VEBs may be used to divert the direction of
contaminated groundwater flow to keep it from
reaching drinking water wells, wetlands, or streams.
They also may be used to contain and isolate
contaminated soil and groundwater" (EPA 2012h).
Common types of VEBs include slurry walls and sheet
pile walls.
Vapor Intrusion Mitigation
"[Vapor] intrusion is the general term given to
migration of hazardous vapors from any subsurface
contaminant source, such as contaminated soil or
groundwater, through the vadose zone and into the
indoor air, usually of overlying buildings through
openings in the building foundation (e.g., through
cracks in the slab, gaps around utility lines, or elevator
shafts). Contaminants that may result in vapor
intrusion include volatile organic compounds (VOCs)
and other vapor-forming chemicals, such as some
semivolatile organic compounds, elemental mercury,
and radionuclides. VOCs typically pose the most
common vapor intrusion concerns" (EPA 2012i).
Appendix A: Definitions of Selected Remedies
A-9
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Superfund Remedy Report, 14th Edition
Active Soil Depressurization (ASD) includes a
"venting system consisting of a vent pipe (or a series of
vent pipes) installed through the slab and connected
to a vacuum pump to extract the vapors from beneath
the slab" (EPA 2008a). "This approach is the most
thoroughly studied and demonstrated approach for
mitigating vapor intrusion. This approach consists
of a group of methods that site teams can customize
to treat different construction features of a building,
including sub-slab depressurization (SSD), drain tile
depressurization, wall depressurization, baseboard
depressurization, and sub-membrane depressurization"
(EPA 20121). An ASD system may be used in
conjunction with a vapor barrier.
Passive Soil Ventilation (PS V) "involves installing a
venting layer beneath a building. Wind or the build-up
of vapors causes vapors to move through the venting
layer toward the sides of the building where it is
vented outdoors. A venting layer can be installed prior
to building construction as well as within existing
buildings. It is usually used with a vapor barrier" (EPA
2012g).
Positive Indoor Pressurization "involves adjusting the
building's heating, ventilation, and air-conditioning
[HVAC] system to increase the pressure indoors
relative to the sub-slab area. This method is typically
used for office buildings and other large structures"
(EPA 2012g).
Indoor Ventilation — "Some natural ventilation
occurs in all buildings. By opening windows, doors,
and vents, ventilation increases. This increase in
ventilation mixes outdoor air with the indoor air
containing VOC vapors, and reduces indoor levels
of the contaminants. However,.. .if a building is
experiencing a 'stack effect', which is normal, opening
a window only in an upper story above the neutral
pressure plane can increase the inflow of soil gas and
thus be counterproductive. Moreover, once windows,
doors, and vents are closed, the concentration of
VOCs most often returns to previous values within
about 12 hours" (EPA 2008a).
Sealing Cracks and Openings "involves filling in
cracks in the floor slab and gaps around pipes and
utility lines found in basement walls" (EPA 2012g).
Passive Barrier (Impermeable Membrane)
Installation involves "placing sheets of
'geomembrane' or strong plastic beneath a
building to prevent vapor entry. Vapor barriers
are best installed during building construction,
but can be installed in existing buildings that
have crawl spaces" (EPA 2012g). Spray-on
vapor barriers (rubberized asphalt emulsions or
epoxy) may also be used (EPA 2008a).
Other or Unspecified Remedies
Alternative Water Supply (AWS): "In CERCLA,
section 101 (34) states that '[t]he term 'alternative
water supplies' includes, but is not limited to, drinking
water and household water supplies.'Also, CERCLA
section 118 states that in taking response actions, the
President [EPA] shall 'give a high priority to facilities
where the release of hazardous substances or pollutants
or contaminants has resulted in the closing of drinking
water wells or has contaminated a principal drinking
water supply.'...Providing an alternative supply
of water to affected users generally is designed to
prevent residents from being exposed to contaminated
groundwater.. ..Providing an alternative water supply
may involve furnishing clean, drinkable water on a
permanent or temporary basis. For example, providing
a permanent supply of drinking water may include
installing a private well, connecting to a municipal
water system, drilling of a new community water
supply well, or reinstating a previously contaminated
water supply well once the groundwater has been
cleaned up. Examples of providing a temporary supply
of water may involve installing individual treatment
units or delivering bottled water. When a [Superfund]
response action that provides an alternative water
supply involves connecting hundreds of homes to a
municipal system (i.e., a residential connection to a
water purveyor), it generally means that [residents
are connected] to a water supply line that is located
relatively close by" (EPA 2010b).
Fracturing for Site Cleanup — "Fracturing creates
or enlarges openings in bedrock or dense soil,
such as clay, to help soil and groundwater cleanup
methods work better. The openings, called "fractures,"
become pathways through which contaminants in
soil and groundwater can be treated in situ (in place,
underground) or removed for above-ground treatment.
Appendix A: Definitions of Selected Remedies
A-10
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Superfund Remedy Report, 14th Edition
Although fractures can occur naturally in soil and
rock, they are not always wide or long enough to easily
reach underground contamination using cleanup
methods. Fracturing can enlarge the cracks and create
new ones to improve the speed and effectiveness of the
cleanup" (EPA 2012c).
Fracturing for site cleanup is different from fracturing
to recover oil and gas. "Oil and gas hydraulic fracturing
is used to stimulate the recovery of oil or natural gas
from underground geologic formations. Oil and gas
hydraulic fracturing works by pumping a mixture of
fluids and other substances into the target formation
to create and enlarge fractures. Such operations are
much larger, use different equipment and chemical
additives, occur at greater depths, and use higher
volumes of fluid than fracturing for site cleanup.
Fracturing to clean up a contaminated site rarely
exceeds a depth of 100 feet, and the affected area
around the fracturing well usually is less than 100
feet in any direction. However, wells to extract oil and
gas often are drilled hundreds or thousands of feet
downward and sometimes horizontally into the oil- or
gas-bearing rock. Fractures may extend over 500 feet
from these wells" (EPA 2012c).
Institutional Controls are defined by the EPA as
"non-engineered instruments, such as administrative
and legal controls, that help to minimize the potential
for exposure to contamination and/or protect the
integrity of a response action. ICs typically are
designed to work by limiting land and/or resource use
or by providing information that helps modify or guide
human behavior at a site. ICs are a subset of Land
Use Controls (LUCs). LUCs include engineering and
physical barriers, such as fences and security guards, as
well as ICs" (EPA 2012k). Some common examples of
ICs include zoning restrictions, building or excavation
permits, well drilling prohibitions, easements, and
covenants.
Soil Amendments — "Many soils, particularly those
found in urban, industrial, mining, and other disturbed
areas, suffer from a range of physical, chemical, and
biological limitations. They include soil toxicity,
too high or too low pH, lack of sufficient organic
matter, reduced water-holding capacity, reduced
microbial communities, and compaction. Appropriate
soil amendments may be inorganic (e.g., liming
materials), organic (e.g., composts) or mixtures (e.g.,
lime-stabilized biosolids). When specified and applied
properly, these beneficial soil amendments limit many
of the exposure pathways and reduce soil phytotoxicity.
Soil amendments also can restore appropriate
soil conditions for plant growth by balancing pH,
adding organic matter, restoring soil microbial
activity, increasing moisture retention, and reducing
compaction." (EPA 2007).
Wetlands Replacement — "Compensatory mitigation
is required to replace the loss of wetland and aquatic
resource functions in [a] watershed. Compensatory
mitigation refers to the restoration, establishment,
enhancement, or in certain circumstances preservation
of wetlands, streams or other aquatic resources for
the purpose of offsetting unavoidable adverse impacts
[from a specific project (EPA 2008b). For the purposes
of this report, mitigation performed at the site of the
adverse impacts is excluded from the definition of
wetlands replacement. For mitigation performed at
the site of adverse impacts, see Wetlands Restoration.
For wetlands constructed as a form of treatment, see
Constructed Treatment Wetlands.
Wetlands Restoration is defined as "[r]e-establish-
ment or rehabilitation of a wetland or other aquatic
resource with a goal of returning natural or historic
functions and characteristics to a former or degraded
wetland" (EPA 2008b). For the purposes of this
report, restoration conducted at a location other than
the impacted site is excluded from the definition
of wetlands restoration, and is instead considered
Wetlands Replacement. For wetlands constructed
as a form of treatment, see Constructed Treatment
Wetlands.
Appendix A: Definitions of Selected Remedies
A-11
-------
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Index
Activated carbon treatment A-7—A-8
Active soil depressurization iv, A-10
Air sparging 13, A-l, B-l
Alternative water supply iv, 13,20, A-10
Annual Status Report iv, 3,15,20,22
Arsenic 2,16,19
ASD. See Active soil depressurization
ASR. See Annual Status Report
AWS. See Alternative water supply
B
Benzene, toluene, ethylbenzene, xylene iv, 17
Bioaugmentation 13,14, A-4
Biological treatment A-l, A-4-A-5
Bioremediation 1,2,5, 8, 9,10,12,13,14,19,20,21, A-3, A-4,
A-5, B-l
BTEX. See Benzene, toluene, ethylbenzene, total xylenes
CAD. See Contained aquatic disposal
Caps and Cover Systems A-9
CERCLA. See Comprehensive Environmental Response,
Compensation and Liability Act
CERCLA Information System iv, 3,16,21
CERCLIS. See Comprehensive Environmental Response,
Compensation and Liability Information System
CFR. See Code of Federal Regulations
Chemical oxidation A-3-A-4
Chemical reduction A-3, A-4
Chemical treatment 9,10,13,14, A-l, A-2, A-3-A-4, B-l
CLU-In. See Hazardous Waste Cleanup Information
COC. See Contaminant of concern
Code of Federal Regulations iv, 5, 7,21, A-l
Comprehensive Environmental Response, Compensation and
Liability Act iv, 5, A-l, A-10
Constructed treatment wetlands 9,11,13, A-4, A-5, A-ll
Contained aquatic disposal iv, A-9
Containment 1,2,4,5, 6, 7, 8,11,12,13,19,20, A-l, A-6,
A-9-A-10
Dense non-aqueous phase liquid iv, 4, A-2
Depressurization
sub-membrane 2, 15, 16, A-10
sub-slab iv, 2,15, 16,19, A-10
Disposal iv, 1, 6, 7, 8,11, A-l, A-2, A-9
DNAPL. See Dense non-aqueous phase liquid
Dredging 11
Dual-phase extraction A-2
Electrical resistance heating iv, A-5
Electro kinetic separation A-2, B-l
EMNR. See Enhanced monitored natural recovery
Engineering controls 13, A-5
Enhanced monitored natural recovery iv, 5, 6, 7,11, A-8, A-9
EOU. See Excess, obsolete, or uncerviceable
EPA. See U.S. Environmental Protection Agency
ERH. See Electrical Resistance Heating
ESD. See Explanation of Significant Differences
ET. See Evapotranspiration
Evapotranspiration iv, A-9
Excess, obsolete, or unserviceable iv, A-5
Explanation of Significant Differences iv, 1, 3, 4, A-l
Ex situ treatment 1,5, 8, 9,11,19, A-6
F
Federal Remediation Technologies Roundtable iv, 21, A-l, A-6,
A-7,A-8
Filtration A-7
Flushing 9, A-2, B-l
Fracturing 9,13,20, A-10-A-11
FRTR. See Federal Remediation Technologies Roundtable
GAC. See Granular activated carbon
Granular activated carbon iv, A-7
Groundwater
media 1, 2, 3, 4, 5, 6, 12-15, 18, 19, 22, A-l, A-2, A-3, A-4,
A-5, A-6, A-7, A-8, A-9
remedies 1, 3, 4, 5, 12-14, 19, A-l
Hazardous Waste Cleanup Information iii, iv, 22
Hexavalent chromium 2,16,19
High-resolution site characterization iv, 2,19, 21
HRSC. See High-resolution site characterization
HVAC. See Heating, ventilation and air conditioning
1C. See Institutional control
Incineration A-5-A-6, B-l
Indoor ventilation 2, 15, A-10
In situ 1,14, A-5
chemical oxidation iv, 8, 13, 14, A-4
chemical reduction iv, 8, 14, 20, A-3, A-4
treatment 1, 10, 11, 12, 14, 19, 22, A-l
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Superfund Remedy Report, 14th Edition
Institutional control iv, 1,4,5, 6, 7, 8,11,12,13,16,19,21, A-ll
Interstate Technology & Regulatory Council iv, 21, A-3, A-4,
A-5
In-well air stripping 13, A-2
Ion exchange A-7
ISCO. See In situ chemical oxidation
ISCR. See In situ chemical reduction
ITRC. See Interstate Technology & Regulatory Council
Lead 2,16,17,19
Light non-aqueous phase liquid iv, 4, A-2
LNAPL. See Light non-aqueous phase liquid
Mechanical soil aeration A-2, B-l
Mercury 2,15,16,17,19, A-9
Metals precipitation A-7
MNA. See Monitored natural attenuation
MNR. See Monitored natural recovery
Monitored natural attenuation iv, 1, 5, 6,12,13,14,19, A-l,
A-8-A-9
Monitored natural recovery iv, 1, 5, 6, 7,11, A-l, A-8
MPE. See Multi-phase extraction
Multi-phase extraction iv, 1, 8, 9,10,13,19, A-2, B-l
N
NA/NFA. See No action/no further action
Nanoremediation A-4
Nanoscale zero-valent iron iv, A-4
NAPL. See Non-aqueous phase liquid
National Oil and Hazardous Substances Pollution Contingency
Plan iv,5,7
National Priorities List iv, 3, 5,16
NCP See National Oil and Hazardous Substances Pollution
Contingency Plan
Neutralization 14, A-4, B-l
No action/no further action iv, 5, 6
Non-aqueous phase liquid iv, 4, 9,18, A-l, A-2
NPL. See National Priorities List
nZVI. See nanoscale zero-valent iron
OB/OD. See Open burn/open detonation
Office of Solid Waste and Emergency Response iv, 20,21
Open burn/open detonation iv, A-5, B-l
Operable unit iv, 3,17
OSWER. See Office of Solid Waste and Emergency Response
OU. See Operable unit
Ozone sparging 14, A-2
PAH. See Polycyclic aromatic hydrocarbon
Passive barrier 16
Passive soil ventilation iv, 16, A-10
PCB. See Polychlorinated biphenyl
Permeable reactive barrier iv, 13, 21, A-4
Physical separation 8, 9, A-2, B-l
Physical treatment A-l-A-3
Phytoremediation 9,13, A-4, A-5, B-l
Polychlorinated biphenyl iv, 2,16,17,19, A-7
Polycyclic aromatic hydrocarbon iv, 17,18
Positive indoor pressurization 16, A-10
PRB. See Permeable reactive barrier
PSV. See Passive soil ventilation
P&T See Pump and treat
Pump and treat iv, 1, 9,12,13,14,19,20, A-l, A-6, A-7
RCRA. See Resource Conservation and Recovery Act
Record of Decision iv, 1, 3, 4, A-l
Recycling 9
Remedial Investigation/Feasibility Study iv, 2,16,17,18,19,22
Remedy selection trends 5, 6
Resource Conservation and Recovery Act iv, 20
RI/FS. See Remedial Investigation/
Feasibility Study
ROD. See Record of Decision
Sealing cracks and openings 2,15,16, A-10
Sediment 1,4,5, 7,11,18,19,22, A-l, A-5, A-6, A-8, A-9
media 18, A-8, A-9
remedies 1, 7
SEE. See Steam enhanced extraction
Semivolatile organic compound iv, 15,16,17,18,19, A-6
Soil
media iv, 1, 2, 4, 8, 9, 10, 15, 18, 19, A-l, A-2, A-3, A-4, A-5,
A-6, A-8, A-9
Soil vapor extraction iv, 8, 9,19, A-l, A-2, A-6, B-l
Soil washing A-2, B-l
Solidification/stabilization iv, 1, 8, 9, 10, 11,19, A-2, A-3, B-l
Solvent extraction A-3, B-l
Source 1,3,4,5,7-12,19,22, A-l, A-2, A-3, A-4, A-6, A-8,
A-9
media 1, 4, A-l, A-2
remedies 7-10, 19
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Superfund Remedy Report, 14th Edition
SRR. See Superfund Remedy Report
S/S. See Solidification/stabilization
SSD. See Sub-slab depressurization
Steam enhanced extraction iv, A-5, A-6
Stream realignment 11
Subaqueous containment cell ll,A-9
Subaqueous non-reactive cap 11, A-9
Subaqueous reactive cap 9,11, A-4
Superfund Remedy Report iv, 1,3,4,5,15,20,22
Surface water 13
SVE. See Soil vapor extraction
SVOC. See Semivolatile organic compound
TCE. See Trichloroethene
TCH. See Thermal conduction heating
Thermal desorption 9,20, A-5-A-6, B-l
Thermal treatment 9,10,11, A-l, A-5-A-7, B-l
Treatment technology 4, 5, A-l
Trichloroethene iv, 2, 16, 17, 19
u
U.S. Environmental Protection Agency iv, 1, 3, 5, 7,15,16,19,
20,21,A-1-A-11
Vapor intrusion 1,2, 3, 5, 6,15-16,19,22, A-9-A-10
VEB. See Vertical engineered barrier
Vertical engineered barrier iv, 12,13, A-l, A-9
Vitrification A-6, B-l
VOC. See Volatile organic compound
Volatile organic compound iv, 15,16,17,18,19, A-l, A-2, A-6,
A-7,A-9
Wetlands replacement 11, A-5, A-ll
Wetlands restoration 11, A-ll
Zero valent iron iv, A-3, A-4
ZVI iv. See Zero valent iron
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