.
O
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Office of Solid Waste EPA 542-R-04-011
and Emergency Response March 2005
(5102G) www.clu-in.org
www.rtdf.org
A Decision-Making Framework for Cleanup of
Sites Impacted with Light Non-Aqueous Phase
Liquids (LNAPL)
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Table of Contents
NOTICE Hi
ACRONYMS iv
EXECUTIVE SUMMARY v
1.0 INTRODUCTION AND OBJECTIVES 1
2.0 ORGANIZE RESOURCES 5
2.1 ASSESS CURRENT STATE OF KNOWLEDGE 6
2.2 DEVELOP THE CONCEPTUAL MODEL 7
2.3 ORGANIZE THE STAKEHOLDER PROCESS 7
2.4 IDENTIFY STAKEHOLDERS 8
2.5 DESIGN, AGREE TO, AND IMPLEMENT A CONSENSUS-BASED PROCESS 8
3.0 DEVELOP THE LONG-TERM VISION AND GOALS 10
3.1 Discuss STAKEHOLDER INTERESTS 12
3.2 DEVELOP A COMMON UNDERSTANDING OF THE PROBLEM 14
3.3 PREPARE THE LONG-TERM VISION STATEMENT 14
3.4 ESTABLISHLNAPLMANAGEMENT GOALS 15
3.5 DOCUMENT AND COMMUNICATE THE CONSENSUS PROCESS, LONG-TERM
VISION, AND LNAPL MANAGEMENT GOALS 17
4.0 COLLECT AND ANALYZE SUPPLEMENTAL DATA 19
4.1 OBJECTIVES AND TARGET s FOR THE SUPPLEMENTAL INVESTIGATION 19
4.2 LNAPL DISTRIBUTION 20
4.3 LNAPL MOBILITY AND PLUME STABILITY 21
4.4 LNAPL RECOVERABILITY 23
4.5 FIELD DATA COLLECTION 24
4.6 LABORATORY ANALYSES 24
4.7 DATA INTERPRETATION 25
5.0 REVIEW AND REFINE CONCEPTUAL MODEL, LONG-TERM
VISION, AND GOALS 28
6.0 IDENTIFY, EVALUATE, AND SELECT MANAGEMENT OPTIONS 30
6.1 IDENTIFY AND EVALUATE LNAPL MANAGEMENT OPTIONS 31
6.2 TREATMENT, REMOVAL, AND CONTAINMENT TECHNOLOGIES 32
6.3 SELECT AND TEST TECHNOLOGY 34
7.0 DEFINE ENDPOINTS AND DEVELOP CONTINGENCY PLAN 36
8.0 IMPLEMENT AND MONITOR PERFORMANCE 40
9.0 EVALUATE PROGRESS 42
APPENDIX A: CURRENT CONDITIONS CHECKLIST 45
APPENDIX B: POTENTIALLY AFFECTED INTERESTS MATRIX 51
APPENDIX C: SELECTION OF LNAPL MANAGEMENT OPTIONS 52
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APPENDIX D: SELECTED LNAPL CHARACTERIZATION AND
REMEDIATION TECHNOLOGY PUBLICATIONS 55
APPENDIX E: REFERENCES 68
LIST OF TABLES
TABLE 1. EXAMPLES OF TYPICAL STAKEHOLDER INTERESTS 13
TABLE 2. HYPOTHETICAL EXAMPLES OF STAKEHOLDER INTERESTS 14
TABLE 3. EXAMPLE GOALS 16
LIST OF FIGURES
FIGURE ES-l.NAPL MANAGEMENT PROCESS vi
FIGURE 1. NAPL MANAGEMENT DECISION-MAKING FRAMEWORK PROCESS 4
FIGURE 2. HYPOTHETICAL DECLINE CURVE FOR AN LNAPL RECOVERY SYSTEM 27
FIGURE 3. HYPOTHETICAL CUMULATIVE RECOVERY FOR AN LNAPL RECOVERY SYSTEM. 27
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Notice
This document was developed by the Non-Aqueous Phase Liquid (NAPL) Cleanup
Alliance (the Alliance). The Alliance, established in 2001, is one of the six active Action
Teams under the Remediation Technologies Development Forum (RTDF). The RTDF
was established in 1992 to foster collaboration between the public and private sectors in
developing innovative solutions to mutual hazardous waste problems. The NAPL
Cleanup Alliance includes representatives from the petroleum industry, federal and state
government, and academia who share an interest in pursuing aggressive technologies for
removing large-scale non-aqueous phase liquid (NAPL) contamination. The Alliance's
work has focused on a number of activities, of which this document is a part, all
dedicated to finding more practicable and reasonable ways of cleaning up sites that have
been impacted by petroleum hydrocarbons. More information about the Alliance can be
found at http: //www. rtdf. org.
This document has been prepared as a guide for long-term management of light, non-
aqueous phase liquid (LNAPL) at impacted sites. The document has been reviewed by a
broad stakeholder group that includes U.S. EPA and state entities. This document is not a
U.S. EPA policy, guidance, or regulation. It does not create or impose any legally binding
requirements or establish U.S. EPA policy or guidance. The U.S. EPA does not exercise
editorial control over the information in this document, and Standards of Ethical Conduct
do not permit the Environmental Protection Agency (EPA) to endorse any private sector
product or service. The Alliance hopes to disseminate the information in the document
through presentations, workshops, Internet seminars, etc., so that it can be made available
to all who have a need for such assistance. To further their goals, the Alliance is also
conducting pilot projects and preparing training modules, all related to LNAPL
management.
Definitions
The following definitions are provided to promote common understanding of the terminology
used throughout the document.
Long-Term Vision is the qualitative statement of the ultimate desired situation or condition at
the site. Achieving the long-term vision will likely require iterative steps through the LNAPL
management process.
Goals represent the specific elements that enable achievement of the long-term vision,
representing intermediate steps on the way to the long-term vision. Goals can be short-,
intermediate-, or long-term.
Endpoints are the measurable criteria, specifically associated with each goal, which
demonstrate progress towards achieving the goal.
LNAPL management options include active or passive technologies for remedial action,
and/or engineering or institutional controls. The implementation of the LNAPL management
option is the means to achieving the long-term vision.
Regulatory requirements are those actions and specifications that are mandated by the laws
and regulations that apply to a particular site, with respect to corrective-action activities (e.g.,
meeting groundwater or surface- water standards, discharge permits for remedial action
systems, local zoning requirements). These regulatory requirements become part of the
constraints for the LNAPL Management Plan.
LNAPL Management Plan is the overall decision-making framework for the site.
iii
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ACRONYMS
API American Petroleum Institute
ARAR Applicable or Relevant and Appropriate Requirements
COC Chemicals of Concern
CPT Cone Penetrometer Technology
DNAPL Dense Non-aqueous Phase Liquid
EPA Environmental Protection Agency
LIF Laser Induced Fluorescence
LNAPL Light Non-aqueous Phase Liquid
LNAST Light Non-aqueous Screening Tool
MIP Membrane Interface Probe
MNA Monitored Natural Attenuation
NAPL Non-aqueous Phase Liquid
RCRA Resource Conservation and Recovery Act
ROST Rapid Optical Screening Tool
RTDF Remediation Technologies Development Forum
TCEQ Texas Commission on Environmental Quality
TPH Total Petroleum Hydrocarbons
IV
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Executive Summary
Purpose and Background
A Decision-Making Framework for cleanup of sites impacted with light, non-aqueous
phase liquids (LNAPL) has been prepared by the Remediation Technologies
Development Forum (RTDF) NAPL Cleanup Alliance to provide a guide to practicable
and reasonable approaches for management of LNAPL petroleum hydrocarbons in the
subsurface. This unique document describes an innovative consensus-based process to
develop a long-term vision for a particular site (e.g., an industrial site for the next 100
years with groundwater standards attained in 125 years), while providing a roadmap that
calls for specific goals and endpoints to measure progress during each phase of the
LNAPL management project. The major benefit of this innovative approach is the
establishment of a practicable vision that is consistent with regulatory requirements and
can be attained within a realistic timeframe and a reasonable budget, using a phased,
stepwise process. The consensus-based process is designed to support the stakeholder
group in developing a common, site-specific understanding of what "realistic
timeframes" and "reasonable budgets" will mean for any particular site.
The Decision-Making Framework has been designed for application at sites that are
impacted by petroleum hydrocarbons in the subsurface, with special focus on large
complex sites, such as operating and closed petroleum refineries, pipelines, shipping
terminals, and tank farms. This document strives to provide a framework for making
sound, scientifically-based decisions for LNAPL management, which may shorten the
cleanup timeline. LNAPL management, which is the focus of this document, represents
only a portion of the environmental work ongoing at these sites. However, sound LNAPL
management can significantly impact the overall cleanup timeline for the site. Because
LNAPL in the subsurface presents complex technical challenges and long-term financial
commitments, a phased approach to LNAPL management is recommended. Regulatory
concurrence should be sought for the LNAPL management strategy that results from use
of the Decision-Making Framework for a particular site.
Key components of the Decision-Making Framework are its flexibility and the iterative
nature of the process, where vision and goals are revisited and revised as new data and
information are obtained throughout the various steps of the process during each phase of
the project. Decisions are made, and revised if necessary, based upon the latest
information to ensure the approach maintains its reasonableness and practicability. The
Decision-Making Framework, based upon the following definitions, consists of the
following steps depicted in Figure ES-1. Each of the major steps is described further in
this executive summary and in the noted Sections of the report, 2.0 through 9.0. Key
LNAPL management questions asked during each step of the process are shown to the
right of the flow chart. The Decision-Making Framework is designed to address sites
where imminent hazards are already under control and site managers know that an
LNAPL problem exists.
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Enter Process
Yes
Organize Resources (Section 2.0)
CDeveloc Conceptual Model & Initiate Stakeholder Process")
i
r
Develot) Lona-Term Vision and Goal ("Section 3.01
i
r
Evaluate Risk & Technical Issues/Limitations
Determine LNAPL Distribution, Mobility and Recoverability
(Section 4.0)
Review Conceptual Model, Risks, Long-Term Vision and Goals
(Section 5.0)
Identify, Evaluate, and Select Management/Technology Options
(Section 6.0)
Define Endpoints/Develop Contingency Plan
(Section 7.0)
Implement and Monitor Performance (Section 8.0)
nt Option
.i * *
on track to meet
ndpomts, Goal and
Vision^
Implement contingency plan or reevaluate
long-term vision or management options
Key Mgm't Questions
Is the site secure?
Are the appropriate
stakeholders involved?
Has an acceptable Long-
Term Vision been
developed?
Are the long-term risks and
technical issues/limitations
understood?
Has a technical /
administrative strategy
been developed and agreed
Has the strategy been
implemented?
Is the plan on track to meet
Endpoints / Goals / Long-
Term Vision?
Figure ES-1. NAPL Management Process
Organize Resources
Once it has been recognized that LNAPL is present and must be managed at a site (e.g.,
based on unacceptable impacts and associated risk, by the owner or operator, a regulatory
agency, or community stakeholder) and immediate hazards and risks have been
controlled, resources, which include human, financial, and information, should be
organized and carefully evaluated. The current state of knowledge is first assessed to
provide a foundation for the project. Appendix A contains a "Current Conditions"
checklist that may be a useful tool to accomplish this activity. This information can be
used to build the conceptual model, which describes potential exposure pathways,
VI
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including sources of chemicals of concern (COCs), environmental media, and potential
receptors under current and potential future activity and land use.
The next activity involves organization of a stakeholder process, where all those who can
affect the outcome or can be impacted by the outcome are invited to participate. The
stakeholders include the regulatory agency(ies), local government, community members,
adjacent landowners and others. This process can be accomplished in a variety of ways,
depending upon the needs of the specific site and the culture of the community.
Suggestions for organizing the stakeholder process are provided as a series of steps.
Develop the Long-Term Vision and Establish LNAPL Goals
After the stakeholder group is convened, their major focus should be on developing a
long-term vision for the site with regard to LNAPL management, incorporating
regulatory requirements and other issues, such as land-use considerations. Often it is
difficult to obtain consensus on a vision; the process may take some time, as the
stakeholder group works together, developing trust and respect for one another's
interests. Once a consensus-based, long-term vision has been developed, the responsible
party and the regulatory entity should identify and agree to specific, measurable,
achievable, cost-effective goals for LNAPL management. Goals should be established for
each phase of the project, short-, intermediate-, and long-term. It is not a requirement to
establish the goals for multiple phases all at once. The process provides the flexibility to
be applied iteratively. However, the stakeholders should consider the long-term vision
and how the goal for an interim phase will influence the later phases. The timeline for the
various phases of LNAPL management may be tied into various land-use scenarios.
Collect and Analyze Supplemental Data
After establishment of specific goals, the stakeholder group should identify information
and data gaps to evaluate whether goals can be attained, given the current understanding
of available remedial approaches and technologies. A supplemental investigation may be
designed to answer targeted questions that provide specific information needed to assess
options for LNAPL management. The major questions to be answered relate to
improving understanding of the distribution, mobility, recoverability, characteristics of
the LNAPL, regulatory requirements, and potential risks associated with the proposed
land use at the site.
Review and Revise Conceptual Model
The conceptual model developed at the beginning of the process, while organizing
resources and assessing current conditions, should be reviewed in light of supplemental
data collected and analyzed. Included in this review is a re-assessment of the risks and
how they may be met by the long-term vision and goals set by the stakeholder group. If
significant changes to the conceptual model have been made and/or risks have changed
significantly, the long-term vision and goals should be revisited, before management
options are identified and evaluated.
VII
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Identify, Evaluate, and Select LNAPL Management Options
LNAPL management options should be identified and evaluated based upon the
information collected in the early and supplemental phases of investigation, the
conceptual model, and risks. The first step involves screening of a broad list of LNAPL
management options, which include active and passive technologies, institutional and
engineering controls, and combinations thereof. The next step involves detailed
evaluation and prioritization of the most promising options based upon a set of criteria
agreed to by the stakeholder group. Selection of management options may be contingent
upon laboratory or field pilot tests conducted to provide critical information to make the
final decision or to optimize implementation of the selected option.
Establish Endpoints and Develop Contingency Plan
The stakeholder group should then identify specific endpoints and timelines for each of
the LNAPL management goals, so that progress towards reaching the goals can be
measured. Endpoints may be performance-based specific to a management option or may
reflect a measurable long-term condition to be attained. Endpoints should be defined with
specifics such as sampling method, analytical method, location of measurement, and
timeframe for measurements. The more specifically the endpoints are defined, the less
likelihood there will be cause for confusion or dissension among the stakeholders.
A contingency plan should also be developed with the assumption that endpoints may not
be achieved, management options may not allow you to attain the goals, etc. The
contingency plan should be inclusive enough that it details all potential failures and
identifies potential solutions, including revisiting of the long-term vision and goals,
review of the performance of the management options, and collecting additional data.
Implement and Monitor Performance
Implementation of the LNAPL management strategy will occur in phases as specific
goals are addressed and attained. Performance monitoring related to the implementation
of a management option is necessary so that progress towards meeting the goal, using
endpoints as a measurement tool, can be assessed. After the active phase of LNAPL
management is completed, confirmation monitoring will be required to assess whether
the goal for LNAPL management, incorporating regulatory requirements and land-use
considerations, have been attained and whether the site has reached the point for final
closure and the long-term vision has been attained (if this is the final corrective-measures
phase).
Evaluate Progress
Revisit the LNAPL Management Plan to assess whether progress towards the endpoints
and goals has been made or whether the management option is on track. To evaluate the
progress:
analyze the performance monitoring data to understand the effectiveness of the
LNAPL management option;
VIM
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perform confirmation monitoring if active NAPL management has been
discontinued and review data to confirm that active remediation is no longer
required;
assess whether the goal has been achieved through the measurement of the
endpoints and determine if it is necessary to implement a contingency plan. If this
is the final goal, has the long-term vision been achieved?
The LNAPL Management Plan is a living document that is updated as circumstances
change throughout the NAPL management process. The process is iterative and flexible.
The focus during each phase of the process is the specific goal; ultimately activities are
targeted towards reaching the long-term vision.
IX
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1.0 Introduction and Objectives
The Decision-Making Framework as applied to a particular site is documented in a
consensus-based LNAPL Management Plan, which provides a systematic strategy
to attain a long-term vision for that site, recognizing that each specific site will
differ in some respects from other similar sites. The long-term vision is achieved
through a stepwise process of practical goal setting, using measurable endpoints to
evaluate progress.
The types of sites for which the Framework is most appropriately applied include
operating and closed petroleum refineries, pipelines, shipping terminals, and tank farms.1
However, this LNAPL Decision-Making Framework can be utilized for all sites
regardless of size.
The materials of interest at these sites include:
common liquid products directly produced from crude oil (e.g., gasoline, diesel,
aviation and other fuels);
specialized refined oil products (e.g., motor oil or lubricating oils);
less often, more specialized products, directly or indirectly manufactured from
crude oil.
Uncontrolled releases of these petroleum-based materials infiltrate into the soil and, if
sufficient quantities have been released, ultimately reach groundwater. Collectively, these
oil-based materials do not readily mix with aqueous systems, such as groundwater.2
Therefore, if a sufficient quantity of these oil-based materials is present, these materials
will remain in separate phases. In general, any materials that exhibit these phenomena are
known as non-aqueous phase liquids, or NAPL. Typically oil-based materials are less
dense, or "lighter" than water; thus the acronym LNAPL. The LNAPL phase can also be
the source of specific COCs in the vadose zone and dissolved COCs in the saturated
zone. The impact of COCs dissolved in groundwater and present in vadose-zone soil gas
present significant challenges to selection and implementation of investigation and
remedial measures. These issues are not the subject of this document, but the LNAPL
management strategy should take these corrective-action activities into account. The
consensus-based process for the development of an LNAPL management strategy
outlined in this document is certainly applicable to the development of an overall site
corrective-action strategy for all impacts, but the discussion of such an over-arching
framework is beyond the scope of this document.
Some regulatory agencies are now recognizing that goals set for these sites may be
difficult to achieve within a realistic timeframe. It is also recognized, that at some time
1 Sites handling relatively small quantities of petroleum products, such as gas stations, which typically have problems
that are smaller in scope and also are the subject of federal and state programs focused on underground storage tanks
are not the primary audience for this guide. Certain sections of the document may not be appropriate for some sites.
2 Some fuel additives such as methyl-tert butyl ether and tert-butyl alcohol are more soluble in water than the primary
petroleum hydrocarbons and may impact significant quantities of groundwater.
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after LNAPL removal is implemented, recovery rate will asymptotically approach zero.
Further attempts at removal will become more costly; further removal may be
impracticable. A search for a more flexible NAPL management process that considers
each site individually is underway in some states, whereas other states regulate within
their current laws that specify the same requirements for all sites.
Many states have a non-degradation policy or law for groundwater contamination, which
might lead to the conclusion that ultimately all of the LNAPL should be removed from
the subsurface. The practical implication of these requirements is that the LNAPL
management project may not be completed for a long time; however, the consensus-
based process outlined in this document may be useful for structuring the process and
progress for getting to completion of the LNAPL management project.
For a variety of reasons, LNAPL in the subsurface presents complex technical challenges
to facility owners as well as to federal and state environmental regulatory agencies. For
closed sites, after demolition and removal of processing equipment, tanks, and other
potential sources of LNAPL releases are completed, the properties and quantity of
LNAPL remaining may likely require continued management and evaluation by owners
and regulators for years. LNAPL management can dominate the resources associated
with the remedial action of a site, both in terms of costs borne by the owner as well as
human resources devoted both by the owner and the regulatory agencies. Often LNAPL
is of great concern to area residents and local government; proper management of
LNAPL can aid in the continued operation of active sites in ways acceptable to the local
community, or can speed the re-development or re-use of closed or inactive sites (e.g., a
Brownfields property).
These sites typically have significant financial liability and may require long-term
LNAPL management to achieve an acceptable long-term vision, which is critical to the
LNAPL management process. The issue of long-term financial liability must be
considered during the decision-making process. Imagine how difficult it would be today
to enforce contracts with parties who might have negotiated agreements one hundred
years ago.
The long-term vision will vary from one site to another and may be significantly different
for a refining or storage facility that will continue in operation as compared to a facility
that is closed and will be redeveloped. The goals to achieve the vision need to be defined
in specific and quantifiable terms, so they can be easily measured. Because these sites
typically contain very complex groundwater contamination problems, it may be difficult
to determine whether a cleanup goal can be achieved at the time a remedial action
selection is made. Hence, the recommended approach to reduce uncertainty is to use a
flexible, phased approach to site characterization and remedial action, where goals are
revisited, and revised if necessary, as more data and information are collected.
The Decision-Making Framework outlines the overall process for reasonable and
practicable approaches to LNAPL management and identifies factors to be considered
during creation of the LNAPL Management Plan. It provides a tool for developing a
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scientifically sound LNAPL management strategy for each site pursuant to its unique
conditions. The regulatory requirements, future land use, timing to achieve specific site
conditions and other factors should all be considered in developing the LNAPL
management strategy. There inevitably will be trade-offs between the costs to implement
the various LNAPL management options and the timeframes to meet endpoints. The
consensus-based process is designed to support the stakeholder group as they define the
acceptable trade-offs for a specific site.
The Decision-Making Framework is designed to address sites where some site
characterization data have already been collected, where immediate hazards and risks
have been controlled, i.e., short-term protectiveness goals have been reached,3 and where
site managers know that an LNAPL problem exists.
The LNAPL management process should be flexible and be designed by the stakeholder
group for the site. A variety of approaches may be utilized to achieve the long-term
vision through a collaborative process. The primary audiences for the document are the
facility owners and operators and the federal and state agencies that regulate them. Other
interested parties, such as area residents, community groups, and local government
agencies, may also find the concepts and information useful.
The NAPL Decision-Making Framework is shown in the following flow chart (Figure 1).
Implementation of the decision-making process at a site may include multiple iterations
through goal setting, data collection, and LNAPL-management option selection and
implementation. The process must remain flexible and be tailored to meet site-specific
needs. Figure 1 attempts to capture a complex process, for which all iterations cannot be
identified on a single page. The figure instead provides a typical pathway for the process.
3 Example short-term protectiveness goals are the RCRA environmental indicators: current human exposures are under
control, or do not exist, and existing dissolved-phase plumes of COCs are not expanding above action levels or
adversely affecting surface waters.
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Enter Process
Immediate hazard under
control?
Implement control
measures
Yes
Organize Resources (Section 2.0)
(Develop Conceptual Model & Initiate Stakeholder Process)
Develop Long-Term Vision and Goal (Section 3.0)
Collect and Analyze Supplemental Data (Section 4.0)
(Assess LNAPL Distribution, Mobility, Recoverability)
Evaluate
Risk and
Technical
Issues/
Limitations
Review Conceptual Model, Risks, and Long-Term Vision & Goal (Section 5.0)
Goal still practicable?
Yes
Yes
.
More data needed?
Identify, Evaluate, and Select Management/Technology Options (Section 6.0)
Goal still practicable?
Yes
Define Endpoints/ Develop Contingency Plan (Section 7.0)
Implement and Monitor Performance (Section 8.0)
Evaluate Progress (Section 9.0)
Have
Endpoints been achieved?
Is Management
Option on-track to meet
Endpoints?
Implement Contingency
Plan
Confirmation Monitoring
Is Management
Option on-track to meet
Goal?
Has
the Goal been achieved?
Was this a final
Goal?
Figure 1. NAPL Management Decision-Making Framework Process
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2.0 Organize Resources
The NAPL Decision-Making Framework process begins with the organization
of resources, including understanding current conditions, building a
conceptual model, and establishing an active stakeholder group.
Over the last twenty years, environmental cleanup of impacted sites across the United
States has been fraught with complex regulations, slow progress, elevated costs, distrust
and divisiveness among various stakeholders, and litigation. Since the early 1990's, a
number of attempts at integrating stakeholder collaboration into the cleanup process have
been demonstrated to provide an effective and efficient means to a reasonable and
practicable approach to cleanup (FFRDC, 1996; Scrimgeour et cil., 1994; Bryan, 1997;
Gamman etcil., 2001). Each of these efforts developed a process for effective consensus-
based decision-making with slight variations on a theme. Each also developed a set of
guiding principles, which have many commonalities from one to the next. Each
collaborative process should be designed to meet the specific needs and situation of the
stakeholders at a particular site.
EXAMPLE STAKEHOLDER PRINCIPLES
(Bryan, 1997)
1. The right stakeholders must be involved.
2. A decision-making process that effectively integrates stakeholders and
leads to the resolution of issues must be designed.
3. The process must provide for the collection of information that
stakeholders will need to resolve the issues.
4. The process must include an interactive communication program
responsive to the needs of all stakeholders.
5. Stakeholders must be involved in identifying and jointly framing the
problem.
6. Stakeholders must be involved in developing an Action Plan that
integrates technical, regulatory, and stakeholder interests.
Principles developed by the Alliance for LNAPL management include the following:
1. It is important to understand the current regulatory situation, site conditions,
and stakeholder interests before beginning preparation of an LNAPL
Management Plan.
2. It is recognized that the need for an LNAPL Management Plan will typically
occur after preliminary investigation activities at the site have identified an
LNAPL problem.
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3. Any immediate concerns and hazards have been or are being addressed at the
site before beginning preparation of an LNAPL Management Plan.
4. An effective LNAPL Management Plan should be designed to be a "living"
document that is used to continuously evaluate new data and the results of
remedial actions.
5. All parties understand that for most sites LNAPL may need to be managed for
an extended period of time (the mass left behind will control plume longevity
and risk); new technologies that may enable more mass recovery and shorter
LNAPL management timeframes are being developed and tested.
6. Technical content of the LNAPL Management Plan should contain
components, such as measurable endpoints, closure criteria, and points of
compliance.
7. Site conditions may change over the course of the implementation of the
LNAPL Management Plan.
8. The plan should be flexible to accommodate site changes and to incorporate
technological innovations in data collection or remedial technologies.
9. The LNAPL Management Plan should be consistent with the overall remedial
action plan for COCs in environmental media at the site.
Specific activities for organization of the necessary resources are described in the
following sections.
2.1 Assess Current State of Knowledge
Existing data and other relevant information should be gathered and assessed to provide a
common foundation for the members of the stakeholder group who agree to participate in
the process. This step could start at any time, and probably will have anyway, by some of
the individual entities represented on the stakeholder group. As a practical matter, by the
time a facility is judged as needing an LNAPL Management Plan, there is likely to have
been a significant amount of data collected from the site, and perhaps from off-site. These
data will generally have been obtained by the facility owner/operator and the primary
regulatory agencies, with some data possibly available from other sources. Other relevant
information, however, such as regional land use plans or zoning requirements, may not
yet have been compiled systematically. A detailed "Current Conditions" checklist is
located in Appendix A to help the user determine if the types of information typically
needed are already available for their site.
The Current Conditions Checklist topics include:
regulatory requirements,
LNAPL management program, and
site conditions (of note in Appendix A is the fact that there should be an
assessment of the potential for on-going releases at all refineries, operating or
closed).
The checklist may be a resource to begin stakeholder discussions of LNAPL management
strategy and decision-making, while also enabling rapid identification of data gaps that
must be filled.
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2.2 Develop the Conceptual Model
The process of developing the current state of knowledge for the site should include an
understanding of the contribution of LNAPL to the potential risks associated with both
current and future activities, including consideration of regulatory requirements and land
use. In order to develop this understanding, a conceptual model is often used to describe
the ways in which human and ecological receptors may be exposed to COCs from a site.
The conceptual model is used as a foundation for making calculations of risks to human
and ecological receptors. The conceptual model and subsequent risk assessment are often
developed as part of the overall corrective-action process for a site; if not, these activities
may be considered as part of the LNAPL Management Plan development. Selected
references for developing conceptual models and for conducting risk assessments are
included in Appendix D.
The conceptual model describes potential exposure pathways, including sources of
COCs, environmental media, and potential receptors under current and potential future
activity and land use. These exposure pathways account for the movement of COCs from
sources to places where receptors may be exposed. The impact of LNAPL on the
exposure pathways (e.g., as an on-going contribution of COCs to groundwater or soil
vapor or as a direct contact exposure medium in excavations) should be considered in the
development of the conceptual model and the LNAPL Management Plan.
The conceptual model should also establish the current interpretation of where LNAPL
exists in the subsurface, i.e. the vertical and lateral distribution and the associated
properties of the subsurface media containing the LNAPL, and some estimate of the
nature and mobility of the LNAPL.
2.3 Organize the Stakeholder Process
A broad spectrum of stakeholders should be invited to participate in the process.
Realistically, it may be difficult to obtain a commitment from outside stakeholders.
Ideally, members of the active stakeholder group will have agreed to dedicate a sustained
commitment of time and effort to create a reasonable and practicable LNAPL
Management Plan. Participation by the responsible party and the regulatory agencies is a
minimum requirement. Involvement of the appropriate stakeholders at the beginning of
the process has been demonstrated to expedite a more efficient collaborative process. The
size and complexity of the stakeholder process needs to be proportional to the size and
complexity of the problem.
By focusing the stakeholder group's activities explicitly on the substantive elements of
LNAPL management, i.e., specific goals and associated endpoints, greater progress can
be made during each phase of the project. With focused direction through a consensus-
based process, participants will likely see that individually and collectively their own
work has been made more efficient and necessary technical work has been completed
cost-effectively on an accelerated schedule.
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2.4 Identify Stakeholders
An essential step is to explicitly identify parties (e.g., governmental agencies, community
and other organizations, and individuals), and the key individuals associated with the
parties that have a stake in the development and implementation of the LNAPL
Management Plan. One or more stakeholders interested in developing the LNAPL
Management Plan may typically initiate the stakeholder process. It has been
demonstrated that for highly contentious issues, the stakeholders may benefit by utilizing
an independent resource to convene and facilitate the stakeholder group, so that the
process is perceived as fair. When identifying the stakeholders, it is critical to include all
who can affect the outcome or can be impacted by the outcome. The stakeholder group
should be inclusive, not exclusive. However, all stakeholders may not choose to
participate in the process.
After the stakeholders are identified, they should be contacted to: 1) determine their
interest in participating in the process of planning LNAPL management at the site and 2)
collect information regarding their specific issues, concerns, and interests. A series of
questions, such as the following, may be asked:
What are your expectations about the project?
What resources will you commit to the project?
What benefits do you anticipate from participating in the project?
What other interests do you have related to this project?
How do you regard the other stakeholders likely to participate in the project?
This activity may be conducted by an independent resource.
To manage the process effectively, it may be useful to group stakeholders into two
categories: 1) an active stakeholder group, which typically will include the facility
owner/operator, the primary regulatory agencies (EPA and/or the lead state
environmental agency, and others, such as a local re-development authority, local/county
governmental agencies, civic or neighborhood organizations, and environmental interest
groups), and 2) a broader community of other interested, but not active, stakeholders,
such as regional businesses, other non-profit organizations, and individuals, which may
not have common interests.
2.5 Design, Agree to, and Implement a Consensus-based Process
At the first meeting of the stakeholder group, the need for a consensus-based process
should be discussed and agreed upon, and progress made on designing the overall team
structure and operational procedures. Some principles and practices for reaching
consensus may be considered at this first meeting. There are many techniques for
reaching consensus. The choice of the technique in a specific situation will, however,
reflect the preferences and prior experiences of the various stakeholders. In addition, the
technique should reflect the "culture" of the community. Some communities, for
example, may historically have a tradition of major local or county-agency involvement
in such matters; in others communities, local and county agencies may not be proactively
involved in cleanup decision-making.
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Specific actions to be completed during this step in the process follow.
FORMER AMOCO REFINERY, CASPER WYOMING
AN EXAMPLE OF CONSENSUS DECISION-MAKING
A formal collaborative process was established at the former Amoco
Refinery in Casper WY to deal with the remedial actions, including but not
limited to LNAPL, and future land use for the closed property. In addition to
the site owner and the lead regulatory agency, a Joint Powers Board created
by the city and county governments was established. While regulatory
authority rested solely with the state environmental agency, frequent public
meetings of the three parties, coupled with other techniques that included an
independent facilitator and independent technical panels, set the stage for a
consensus-based decision-making process. This approach provided a
mechanism for extensive involvement of a broader stakeholder group in the
decision-making process (http://www.bp.casper.com).
Define a process for appropriate involvement of each of the individual
stakeholders. Stakeholder representation is critical to success of the project. It
should be recognized that stakeholder participation may change over time.
Agree upon a decision-making process that satisfies all stakeholder expectations
for involvement. Develop ground rules, meeting logistics, meeting schedules, and
decision rules if consensus cannot be reached.
Consider use of third-party assistance (e.g., facilitators for policy issues, fact
finders and/or independent panels for technical issues). An independent convener
and facilitator have been demonstrated to be particularly effective for contentious
projects. A range of resources, such as consultants and academicians, may be
available, utilizing support from EPA or the state. Support will vary based upon
site and state specifics.
Provide education and support to ensure that all stakeholders are capable of
performing their roles and addressing their interests. This may include staff to
support meetings, technical consultants, financial, in-kind and other resources,
which may be provided through EPA or the state.
Address information and data needs to ensure an effective communication
program that focuses on common understanding of technical issues, regulatory
requirements, etc., both within the group and within the broader stakeholder
community.
Ensure a commitment to consensus. Keep the process open, flexible, and creative
to guarantee success. For example, as more data are collected, revisit what has
been agreed to in the past to see if new data and new understanding about LNAPL
conditions require revision in any element of the LNAPL Management Plan, the
long-term vision, or goals previously agreed to, etc. In short, make the consensus
process iterative.
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3.0 Develop the Long-Term Vision and Goals
The long-term vision for the LNAPL Management Plan is meant to be a
qualitative statement of the ultimate desired situation/condition at the site once
specific actions are taken and specific goals are accomplished. While the actual
wording of the statement may be quite general in tone, the vision itself should be
highly site specific. There is no formula or checklist for developing the vision.
The vision may be broader than management of LNAPL, but the LNAPL
Management Plan is intended to move the site towards achieving the long-term
vision.
The long-term vision may focus on, for instance, surface conditions at the site, the impact
of the operations at the site or its surroundings, or some other key or essential feature.
Developing the long-term vision may almost certainly require the use of consensus-
building techniques, both within the stakeholder group and also reflecting the inputs and
concerns of the broader stakeholder community. In some cases, the long-term vision may
change over time, to reflect new technical information about the site, changes in laws and
regulations, proposed land use or other factors. For some cases, such as an operating
refinery, it may not be possible to develop a long-term vision. Short-term and
intermediate goals can be agreed upon, however, for such a condition.
The adage "Start with the end in mind" is highly relevant in developing the long-term
vision. Long-Term Vision statements for LNAPL management for specific parcels of
land may vary greatly, depending on regulatory requirements and the future land use for
the parcel. If a specific site will continue to be used for industrial purposes, the LNAPL
management vision may likely be quite different than where the future use involves
recreation. Similarly, if the site is adjacent to a water body, the long-term vision may be
different than that for a site in a dry upland location.
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THE GUADALUPE OIL FIELD EXAMPLE OF DISPUTE
FOLLOWED BY CONSENSUS
(Gamman, 2001)
To provide resolution for a serious environmental dispute between industry and
governmental agencies on the environmental impacts of the Guadalupe Oil Field
in California, a consensus-based process, was implemented. The process of joint
fact-finding, using a neutral, scientific panel to provide technical input, offered a
unique opportunity for the disputing parties to cooperatively address information
gaps and scientific uncertainty. Together the parties developed a common
understanding of the issues and potential solutions, relying heavily upon the
expertise of the independent panel. The joint fact-finding process involved the
following steps:
identify key issues,
identify and select experts,
define the steps in the process,
review background information and data gaps,
fill data gaps and resolve questions,
develop screening criteria and apply to options,
define performance evaluation criteria and apply to options.
The consensus-based process turned the situation from a significant dispute to a
collaborative effort between the various stakeholders.
Relevant legal and regulatory criteria will almost certainly play a significant role in
developing the long-term vision. These may include both quantitative criteria, such as
numerical standards, as well as non-quantitative or semi-quantitative criteria, such as the
evaluation of the potential utility and cost-effectiveness of various technical alternatives.
Overall protection of human health and the environment will be a fundamental criterion
for all sites; current and potential future use of groundwater beneath the site will often be
a primary concern for most sites.
The process of developing a long-term vision may be difficult and arduous, as often the
stakeholder group has members with divergent interests. However, as the group works
together over time, members can build trust and respect for each other's interests and
eventually come to consensus on a long-term vision. The timeframe for this process will
be very site specific and may range from six months to several years.
The process for developing the long-term vision should remain flexible so that the vision
can be revisited by the stakeholder group at key steps in the process.
3.1 Discuss Stakeholder Interests
Key to development of a consensus-based long-term vision is the integration of the
interests of the stakeholder group. The stakeholder group may almost certainly consist of
individuals or entities with different beliefs, values, culture, tradition, and perceptions,
from which their interests arise. Stakeholders typically exhibit their interests as positions,
which often appear to be opposing. However, discussion of the underlying interests
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provides an improved setting for understanding the positions espoused by each of the
stakeholders and for identifying areas of common interest. It also helps stakeholders to
postpone judgments while learning about others' interests. These are critical steps to
determining the common ground upon which the group can base its decisions.
It is important to remember that various stakeholders will typically have some and
perhaps many interests in common, but will likely have some unique interests (Table 1).
Table 1. Examples of Typical Stakeholder Interests
Stakeholder
Facility Owner
Regulatory
Agencies
Other Stakeholders
(Local/county
agencies, property
owners, special
interest groups, etc.)
Interests
Achieve regulatory compliance
Utilize risk-based techniques
Minimize/eliminate disruption of
operations
Minimize costs
Reduce long-term treatment and
liabilities
Protect human health and the
environment, including groundwater
resources
Protect groundwater resources
Achieve regulatory compliance
Eliminate off-site impacts to receptors
Involve stakeholders
Maintain reasonable schedule
Obtain reimbursement for oversight
costs
Optimize zoning
Maximize tax revenues
Accelerate schedule
Protect human health and the
environment
Maximize quality of life
Protect groundwater resources
Often, a critical interest of the various stakeholders is the future land use associated with
the LNAPL-impacted property, which has significant implications for the future
owner/operator of the site, the agency or agencies with long-term regulatory
responsibilities, and the community. In some cases, the original facility owner/operator
may have stated intent to continue industrial operations at the facility for an indefinite
period into the future; at others, it is clear that the original owner/operator plans to (or
even has already) cease industrial operations and has no intention to re-open them. Table
2 provides examples that demonstrate that some stakeholders may have different interests
from other stakeholders and that the interests may be highly dependent upon the land-use
scenario.
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Appendix B, the Potentially Affected Interests Matrix, provides a template that has been
utilized by some state regulatory agencies to document stakeholder interests for specific
projects.
Table 2. Hypothetical Examples of Stakeholder Interests
Stakeholder
Facility Owner
Facility Owner
Facility Owner
New Facility Owner
Regulatory Agencies
Regulatory Agencies
Other Stakeholders
Other Stakeholders
Facility's Future
Condition
Operating Facility
Property is or will be
closed
Property is to be
transferred to new owner
Property transferred
Operating Facility
Property is or will be
closed
Operating Facility
Property is or will be
closed
Interests
Integrate LNAPL management and
pollution prevention into facility
operations
Identify future land use (e.g.,
dormant, new industrial, commercial,
recreational, mixed use)
Minimize future costs and liability,
e.g., deed restrictions, contractual
obligations
Operate/maintain LNAPL recovery
systems
Minimize costs and liability
Eliminate releases and control
sources
Identify future land use
Operation/maintenance of LNAPL
recovery systems
Protection of public health and the
environment
Optimize future land uses
Economic revitalization
3.2 Develop a Common Understanding of the Problem
The stakeholder group should reassess the current state of knowledge for the site
(Appendix A Current Conditions Checklist), described in Section 2.1, to develop a
common understanding of the problem. By jointly organizing what information is
available, seeking out additional information, and resolving any inconsistencies that may
exist, the stakeholder group can come to a common understanding of the problem.
This step will include sharing of information on technical, regulatory, and stakeholder
issues. Use of a joint fact-finding team (e.g., Guadalupe Oil Field) or an independent
scientific panel (e.g., Amoco Casper) may be recommended to expedite understanding of
technical issues. The ultimate objective of this step is to develop a common information
base for all stakeholders.
3.3 Prepare the Long-Term Vision Statement
On the pathway to creation of the long-term vision, the stakeholder group may choose to
craft a joint work statement that captures the varying interests of the group in question.
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The example below illustrates opposing positions, underlying interests, and a joint work
statement for cleanup of an impacted site where the stakeholder group consists of
extremely divergent interests. This joint work statement is the first attempt at consensus
and illustrates the opposing interests of the various stakeholders. As the stakeholders
work together, they can begin crafting the long-term vision statement for LNAPL
management at the site. Such vision statements typically contain specific components that
inclusively reflect the broad interests of the group.
HYPOTHETICAL EXAMPLE OF A JOINT WORK STATEMENT FOR AN
IMPACTED SITE DEVELOPED BY A DIVERGENT STAKEHOLDER GROUP
(Bryan, 1997)
Divergent stakeholder positions
1. Clean up the site to pristine conditions
2. Clean only the most impacted portions and contain the remainder of the
contamination on site.
Underlying interests that support these positions
1. Reduce health risks to zero or near zero, restore the ecological integrity of the site,
and/or hold the company accountable for past actions
2. Reduce costs, lower health risks to acceptable standards, and avoid further
disturbance to the site.
The Joint Work Statement
How can we
reduce health risks to acceptable levels
protect groundwater resources
restore the ecological integrity of the site
hold the company accountable for past actions
while also
reducing costs and future liabilities
minimizing disruption of operations
achieving regulatory compliance?
Some examples of long-term vision statements include:
Clean up the site to an industrial-use, risk-based standard;
Clean up the site to allow future land use as a recreational facility;
Restore the on-site groundwater quality to state groundwater quality standards.
3.4 Establish LNAPL Management Goals
Goals describe what is needed to obtain the long-term vision. Goals should be reasonable,
practical, and as specific as possible. It may be useful to develop goals based on the
acronym SMARTSpecific, Measurable, Achievable, Results Oriented, and Time-
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bound. A first set of goals, perhaps specifically termed "preliminary" goals, should be
developed as early as possible within the stakeholder group.
One or more goals should be developed for each phase of the LNAPL management
process and should be revisited as the process unfolds to determine their appropriateness
and applicability as new data and other information are collected. For simplicity, it may
be preferable to define goal(s) in terms of a single overarching statement. For example,
the interim-measures phase, often focused on control of existing and potential sources of
LNAPL, may have a specific goal. The longer-term, final corrective-action phase may
have yet another specific goal. All goals for all of the phases are not necessarily
developed at the same time. However, when developing a goal, the long-term vision
should be considered, as well as the influence that intermediate goals may have on
subsequent phases. If the LNAPL plume is sufficiently complex, goals and management
strategies should be developed separately for various areas of the LNAPL plume.
The goals for each phase and area of the plume will be highly site-specific. Table 3
provides an example of specific goals that might be developed for each phase.
Table 3. Example Goals
Project Phase
Interim measures or
intermediate-term
Corrective action or
long-term
Example Goals
Reduce the mobility of on-site LNAPL to a
practical limit by the year 2005.
Achieve risk-based standards at the property
boundary by the year 2015.
As more data are collected, the goal may need to be modified to reflect the improved
technical understanding of the LNAPL distribution and behavior. Less likely, a goal may
need to be shifted in time, for example, from the immediate/short-term protection phase
to the interim-measures phase, or vice versa. In addition, as the LNAPL is managed over
time, new technologies for investigation, remedial action and containment will be
developed. The stakeholder group should continue to revisit the LNAPL management
goal in light of these technology innovations and consider updates as necessary. The
ability of the process to respond to new data and better understanding of site-specific
conditions demonstrates the flexible, iterative nature of the process.
All stakeholders should remember to focus on site-specific factors. The factors may be
either technical or non-technical in nature. Examples of such factors include the presence
of sensitive habitats such as wetlands, any prior or pending related litigation, the relative
role of federal and state environmental issues, specific regional planning goals, or town
vs. county jurisdictional matters (e.g., zoning). In addition to site-specific aspects of a
particular site, the development of goals should be based on consideration of:
regulatory requirements
LNAPL characterization and distribution
current and future land use
existing and/or potential receptors
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technology capabilities and limitations, which should be revisited periodically,
because technologies continue to develop rapidly
interactions with other remedial measures at the site
stakeholder issues, concerns, and interests
cost
risk and uncertainty in those risks
points of compliance
time frames and schedules to reach the goals.
CACHE CREEK STAKEHOLDER GROUP GOALS*:
AN EXAMPLE
In Northern California, a collaborative process was implemented to prepare
the Cache Creek Watershed Management Plan. Building upon their
common interest of maximizing their quality of life, the stakeholder group
developed five overarching goals:
healthy ecosystem
integrated water management
quality recreation
healthy community
healthy economy.
Within each goal, they developed a number of specific objectives for
which they identified data needs and alternative actions to achieve the
objective (www.yolorcd.org/programs/Cache%20Creek).
* These were identified by the stakeholders as goals, but may actually represent
interests. Their specific objectives may be the goals described in this document.
3.5 Document and Communicate the Consensus Process, Long-Term
Vision, and LNAPL Management Goals
The process of developing an LNAPL Management Plan needs to be appropriately
documented. Depending on the size of the stakeholder group, the documentation process
may be relatively informal or highly structured. The formality of the documentation
process should be left up to the stakeholder group. As noted earlier, the "culture" of the
stakeholder group and the broader community will, in part, determine the nature of the
documentation, as well as the communication techniques used. No matter what the
details, the responsibility for documentation and communication rests with the
stakeholders. Key agreements collectively reached by the stakeholder group (on the long-
term vision, goals, endpoints etc.) should be promptly written, circulated in draft among
the stakeholder group, formally agreed to, and distributed more broadly to other
stakeholders, as appropriate.
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If a formal LNAPL Management Plan is prepared it should document the long-term
vision, goals, and endpoints by describing who is going to do what, where, and when,
thus providing a road map. It should be a living document that can be revisited at various
stages of the process. For example, as site assessment and remedial actions are completed
during the interim phase, important data and insights may be obtained. These data and
insights should be utilized to revisit and revise the goals and long-term vision. At that
time, the plan should be modified.
Systematic mechanisms to communicate to the broader community of stakeholders, both
directly by traditional means (open meetings, workshops, open houses, etc.) as well as
through the media, should be developed and implemented throughout the process. Such
techniques are generally familiar to environmental agencies and facility owners or
operators, and need not be described in detail here. However, LNAPL conditions and
issues may not be as familiar to stakeholders, including the general public, as surface-
water and air issues, and there may be a need to explain the unique challenges associated
with LNAPL.
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4.0 Collect and Analyze Supplemental Data
Targeted data collection can support the evaluation of viable LNAPL
management options and the selection of the most appropriate alternative for a
particular site.
Current LNAPL recovery efforts often rely on a relatively incomplete or inaccurate
understanding of the distribution and behavior of the LNAPL. In addition, the types of
data typically collected on environmental projects are often inadequate to quantify
LNAPL distribution and behavior for purposes of selecting technologies or institutional
controls for LNAPL management. This often results in the installation of ineffective
recovery or treatment technologies with limited or inappropriate performance metrics and
endpoints that are not clearly defined.
4.1 Objectives and Targets for the Supplemental Investigation
Proven science should be used to quantify the magnitude and behavior of the LNAPL.
This approach typically requires the installation of additional sampling locations, the
collection of specialized fluid and soil-fluid interaction properties, and the use of
generally accepted evaluation tools and methods. An investigation plan that incorporates
multiple lines of evidence to develop an understanding of LNAPL at a given site is more
likely to be successful than a plan that relies on only one type of data or analysis. The
LNAPL investigation is a crucial component of the LNAPL management strategy.
Investigation results are used to:
provide a more accurate understanding of LNAPL distribution and behavior,
re-assess the current LNAPL management goal in a context of whether it is still
practicable and achievable,
facilitate the selection of appropriate LNAPL management options (i.e., active or
passive technologies, engineering or institutional controls),
design and test the technology or control system to optimize performance and
efficiency,
provide a means of estimating technology or control-system performance as a
benchmark for comparison,
establish a quantifiable endpoint for shutting off active systems,
provide an improved understanding of the relationship of LNAPL to the dissolved
COCs in the groundwater.
A series of questions need to be answered to define the scope of any supplemental
LNAPL investigation.
1. What goal is the investigation intended to support (e.g., LNAPL mobility or mass
reduction)?
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2. What is the purpose of the data collection and what specific questions are to be
answered with the data?
3. What is currently known about the LNAPL distribution and behavior? (Appendix
A Checklist).
4. What field-engineering data should be obtained to quantify LNAPL distribution,
volume and mobility (e.g., laser-induced fluorescence data, soil core data,
LNAPL bail-down tests)?
5. What laboratory data should be obtained to quantify LNAPL distribution volume,
and mobility (e.g., fluid properties, soil properties, soil-fluid interaction
properties)?
6. What models and calculation methods will be used?
7. What field engineering and test data should be obtained to fill technology-
selection data gaps (e.g., pilot tests, treatability tests, geotechnical tests)?
8. What statistical data analysis methods are available to support the selection of
endpoints?
The potential exposure pathways for current and future conditions will dictate data needs.
As examples, if there are concerns about down-gradient receptors that are users of
groundwater, then chemical-component information and the potential for a continuing
down-gradient dissolved-phase plume are important data needs. If the LNAPL contains
light-end volatile components and the vapor diffusion to indoor-air exposure pathway is
of concern due to the locations of buildings, then chemical analyses and vadose-zone soil
properties are important data needs.
Data collection will support the evaluation of viable LNAPL management options and the
selection of the most appropriate alternative for a particular site. The LNAPL
management option evaluation and selection process and the supplemental data collection
process are iterative processes that are dependent upon each other. Therefore, it is
important that there be an understanding of the potential alternatives available for
LNAPL management before designing the data collection process.
The distribution, mobility, recoverability, and characteristics of LNAPL are
the key questions to be answered for LNAPL management using a variety of
methods described in the following sections.
4.2 LNAPL Distribution
An understanding of the distribution of LNAPL in the subsurface is a fundamental
component of any LNAPL management strategy. It is important to recognize that the
simplified cartoons of LNAPL pancakes floating on groundwater do not exist in the real
world. The LNAPL is typically smeared within the capillary fringe, and because of the
water table rise and fall, below the water table. LNAPL shares the pore spaces with the
air, and water above the water table and with water below the water table. The saturation
with respect to LNAPL defines its distribution. LNAPL saturations typically vary
significantly throughout the subsurface. In heterogeneous porous media, common at
many sites, the distribution of LNAPL is typically extremely complex. For sites where
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LNAPL occurs in bedrock, there are added challenges in developing a complete
understanding of the distribution of LNAPL (API, 1999). The heterogeneous nature of
the subsurface makes it cost-prohibitive to develop a comprehensive understanding of
LNAPL distribution. Therefore, it is recommended that site investigation data be focused
on the questions to be answered.
Traditional methods for estimating the distribution of LNAPL in the subsurface include
collection of soil cores, installation of soil borings, and installation of groundwater
monitoring wells with screened intervals that span the water table, using a variety of
drilling techniques, including direct-push methods. Recent applications of geotechnical-
engineering methods (e.g., direct-push) with sensor enhancements allow indirect mapping
of LNAPL distribution in the subsurface (laser-induced fluorescence [LIF], rapid optical
screening tool [ROST], NAPL Ribbon Sampler, Geo Vis). Monitoring wells or soil
borings can provide an indication of whether or not LNAPL exists in soil in a particular
area based on visual inspection of cores obtained during drilling and measurement in
wells. Observation over a period of time may be necessary to verify that LNAPL is not
present in a given area. Permanent monitoring wells may also be useful in recovery
efforts, or in field-testing for recoverability, as discussed below. However, monitoring
wells and soil borings provide limited information about the pore-scale distribution of
LNAPL. The user is directed to http://www.fate.cluin.org and http://www.epareachit.org
for more information.
Soil cores can be examined to develop an understanding of the vertical distribution of
LNAPL. Field tests for the detection of LNAPL in soils are typically qualitative tests to
indicate the presence of NAPL. Simple tests include using a paint filter to increase the
visibility of LNAPL or shaking a sample of soil in a jar to see if a separate LNAPL phase
results. Other tests that require additional equipment include using hydrophobic dyes to
identify LNAPL or a black light to detect fluorescing hydrocarbons (Bedient et al, 1999).
Laboratory methods are discussed below (see Section 4.6). A disadvantage of using soil
cores to develop an understanding of the distribution of LNAPL in the subsurface is the
expense of retrieval and storage of the cores after field and laboratory analyses are
complete. Subsurface heterogeneity makes it difficult to interpolate between drilling
locations; costs often make it prohibitive to place borings close together at a large site.
Additional information on emerging characterization and monitoring technologies can be
found in Appendix D. The primary advantage of the innovative techniques is that they
may enable collection of a larger number of data points for estimation of LNAPL
distribution than traditional methods, so uncertainty may be reduced. Indirect sensing
methods may require confirmation or calibration by more traditional methods, such as
monitoring wells and soil cores. However, the quantity of confirmation samples collected
by traditional methods should be substantially less than would be required if no
innovative technologies were utilized to evaluate LNAPL distribution.
4.3 LNAPL Mobility and Plume Stability
Understanding whether the LNAPL is mobile is important to LNAPL management. In
sedimentary regimes, LNAPL in the subsurface is distributed in the pore spaces between
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the particles. The following discussion focuses on pore-scale mobility. On the plume
scale, movement is described in terms of migration or stability, which is described after
the pore-scale discussion.
In the saturated zone, water is typically the wetting-fluid (i.e., it forms a continuous layer
on, or preferentially wets, the particles) and LNAPL is the non-wetting fluid (i.e., it
resides inside the pore spaces and is surrounded by a film of water). In the unsaturated
zone, where there is an air phase in addition to the water and the LNAPL, the air is the
non-wetting fluid, the water is still typically the wetting fluid, and the LNAPL resides
between the two other fluids (Bedient, et a/., 1999, Charbeneau 2000). The water and the
LNAPL have different densities and therefore different pressures in the pore spaces. The
difference in the pressure of the two liquids is the capillary pressure, which controls the
saturation of LNAPL in the subsurface. As the amount of LNAPL decreases, the pressure
decreases and the capacity of the formation to transmit LNAPL decreases. If LNAPL is
not continuous from one pore to the next, then LNAPL will not flow from one pore to the
next; it will be immobile, which is referred to as the LNAPL residual saturation (API,
1999, Bedient et al., 1999, Charbeneau, 2000). At residual saturation, the LNAPL cannot
move unless the chemical or physical properties of the LNAPL are altered. Examples of
chemical or physical changes that can affect the residual saturation include induced
pressure gradients from a soil vapor-extraction system, changes in interfacial tension
through the use of surfactants, or reduction in viscosity through the addition of heat
(Charbeneau, 2000).
The mobility of LNAPL is a function of its saturation in the subsurface. LNAPL
saturation greater than the residual saturation will constitute mobile LNAPL, whereas
LNAPL saturation less than residual will constitute immobile LNAPL. Defining the
conditions under which the LNAPL at a particular site is or is not mobile is an important
step in the management of the LNAPL. In analyzing LNAPL mobility, it is important to
understand soil-fluid interaction properties (e.g., capillary pressure and relative
permeability), fluid properties (e.g., fluid density, viscosity and interfacial tension), and
hydraulic properties (e.g., hydraulic conductivity, water-table fluctuations). The
distribution of the LNAPL is also dependent upon specific fluid and soil properties.
If an LNAPL recovery system is operating and the recovery is approaching a low rate, the
design, installation, and operating parameters and procedures should be reviewed to
determine if the system is operating properly, or any changes in operation should be
implemented. If after this review, the system is judged to be operating effectively, then it
is likely that the remaining LNAPL is essentially immobile. In the absence of other forces
acting on the LNAPL plume (e.g., a recovery or containment system), if the dissolved-
phase plume has been adequately characterized and monitored and can be shown to be
stable, then the LNAPL plume is likely to be stable (API, 2002).
On a plume scale, LNAPL is often present above residual saturation in the center of the
plume and thus could be considered to have inherent mobility. However, that fact is not
sufficient to describe the footprint of the entire plume. A study of the LNAPL plume at
the fringes may be prudent to understand plume-scale migration of LNAPL. For example,
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because LNAPL saturation decreases to residual toward the fringe of the plume, the
fringe of the plume may be immobile, while the body of the plume is considered to be
stable. Temporal variation in plume characteristics should be considered to address
variability in measurements, such as variations observed as a result of a fluctuating water
table.
On-going LNAPL releases to the surface or subsurface may likely produce a plume that
is not stable. It is possible that if the LNAPL plume appears to be stable under current site
conditions, the LNAPL may still be mobilized by changes in the hydrologic system,
including declining groundwater elevations4. The definition of a stable plume may be
best presented through multiple lines of field, laboratory, and modeling evidence, while
considering temporal variability.
4.4 LNAPL Recoverability
When monitoring wells, recovery wells, or soil borings are installed, a thickness of
LNAPL may be observed on the water table. This thickness is the result of LNAPL
draining from the surrounding pores into the well or boring (which acts like a large pore
in the ground). LNAPL will drain into the borehole, either naturally or due to engineered
controls such as a pump, to the extent that it remains mobile in the area of the monitoring
well. Once the residual saturation is reached, further recovery by pumping methods will
not be possible. The residual saturation is a theoretical endpoint for pumping-based
recovery systems that will not likely be achieved on a field-scale. It is likely that there
will be more LNAPL remaining in the formation than predicted by the residual saturation
(API, 2002). This is because the heterogeneity of the subsurface, inefficiencies in the
recovery-well network, and variability in the estimates of residual saturation will result in
uncertainties in the predictions for an actual pumping system (U.S. EPA, 1996).
The extent and success of LNAPL recovery is, in large part, defined by the geology, fluid
properties, and the technology that is implemented. For fluid flow, e.g., pumping-based
systems, recovery is limited by the residual saturation and the influence of the pumping
system on groundwater and LNAPL movement to the recovery wells. For technologies
such as surfactant washing, steam stripping, and soil vapor extraction, the recovery may
be able to address some portion of the residual saturation after mobile LNAPL has been
removed. These methods have been designed for enhanced mass recovery. The
implementation of these technologies should be considered in the context of potential
exposure pathways that result from the LNAPL as a source of dissolved-phase or vapor-
phase COCs (API, 2002).
The potential exposure pathways associated with the LNAPL (e.g., vapor-phase COC
migration to indoor environments) should be considered in the evaluation of LNAPL
recovery technologies. As noted above, some enhanced mass-recovery methods will
reduce the potential for dissolved-phase or vapor-phase COCs to continue to migrate
away from the LNAPL source. In addition, the potential for the LNAPL management
4 A fluctuating water table will contribute to the smearing of LNAPL across the water table and capillary fringe, which
may reduce LNAPL saturations, by spreading the LNAPL over a greater thickness and reducing mobility and
recoverability.
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option to liberate COCs from the LNAPL into other environmental media (e.g., steam
stripping will generate vapor-phase COCs) should be considered during the evaluation of
LNAPL recovery options, and during the design of a site-specific system.
Typically LNAPL bail-down tests are used to understand the recoverability of LNAPL
using pumping systems in wells. The result of the bail-down test is an estimate of the
LNAPL conductivity and also the local transmissivity of the formation for LNAPL. The
LNAPL recovery rate can be estimated from the transmissivity and a determination made
if that rate is acceptable (typically reviewed and approved by the regulatory agency). A
bail-down test is conducted by removing all accumulated LNAPL in a well and recording
the rate at which LNAPL recharges into the well. Field data are analyzed in similar
fashion as groundwater bail-down tests or slug tests, using methods such as the Bouwer-
Rice method, Lundy and Zimmerman, or Huntley methods (Huntley, 1997; Lundy and
Zimmerman, 1996; BP, 2003; TCEQ, 2003; Charbeneau, 2000; Bedient et al., 1999).
Recovery of LNAPL from the subsurface reduces its saturation, making the LNAPL less
mobile, but also less recoverable. Therefore as the recovery progresses, it becomes less
effective and the actual recovery rate diminishes.
4.5 Field Data Collection
The scope of field data collection should be defined through the series of questions posed
in Section 4.1. Quantity and quality of data will be assessed based on the LNAPL
management goals to be supported and the potential management options to be
considered. If management options are to be pilot tested, the quality and quantity of data
that are required should be decided based on the specifications of the pilot test. Methods
for estimation of LNAPL distribution, mobility, recoverability, and characteristics are
described briefly in Sections 4.2 through 4.4.
4.6 Laboratory Analyses
Laboratory analyses to be performed will vary depending on the management options to
be evaluated for a specific site. Some of the more common laboratory data collected
include basic fluid and soil properties. There are a number of references that provide
recommendations for analytical methods, e.g., API, 1999; API, 200la; TCEQ, 2003. The
methods for each parameter are often updated with newer techniques. It is suggested that
the user consult with the regulatory agency and a qualified analytical laboratory to
develop a site-specific analytical scope of work.
Laboratory analyses of LNAPL are generally performed to measure the following:
density
viscosity
chemical composition
surface tension
LNAPL/water interfacial tension
source petroleum product (i.e., "finger-print" analysis).
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For situations where an LNAPL separate-phase has not been detected in monitoring
wells, or there is insufficient LNAPL in the monitoring wells to collect a sample for
laboratory analyses, total petroleum hydrocarbon (TPH) measurements or other methods
designed to estimate the total concentration of COCs in soil may provide an indication of
LNAPL saturation (Bedient et al, 1999).
Laboratory analyses of core samples are generally performed to quantify the following
soil properties:
grain size
porosity
bulk density
hydraulic conductivity
Atterberg limits (for soil classification)
undisturbed samples (e.g., soil cores) for
saturation analysis for LNAPL and water, including residual saturation
capillary pressure tests
relative permeability tests.
For more information on laboratory analyses, see BP, 2002; TCEQ, 2003; and API,
1996a.
4.7 Data Interpretation
Data interpretation typically requires the use of multiple lines of evidence to analyze both
qualitative and quantitative data to develop an understanding of LNAPL distribution,
LNAPL characteristics, and its mobility and potential recoverability.
A credible estimate of the volume of LNAPL remaining in the formation should be
developed. However, all estimates of LNAPL volume have large uncertainties due to
factors such as heterogeneity of the subsurface, representativeness of the data set, and
variability of LNAPL properties, particularly for multiple or old releases. Basic
calculation of the volume in the subsurface considers horizontal and vertical distribution
of LNAPL and the measured or estimated saturations of LNAPL. It is also important to
estimate the fraction of the total LNAPL volume in the subsurface that is mobile. Some
of the newer investigation techniques that involve indirect sensing with direct-push
methods can produce a three-dimensional interpretation of LNAPL distribution in the
subsurface. Based on these measurements, the volume in the subsurface can also be
estimated. A discussion of the potential uncertainties in the estimated volume of LNAPL
is often helpful to the stakeholder group, while developing a common understanding of
the site.
LNAPL saturation for a site can also be estimated from TPH concentrations or can be
measured in the laboratory. These can be compared to a residual saturation value, either
from the literature (API, 1999) or from laboratory measurements. Caution should be
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exercised when using literature values because of the potential for large differences
between site-specific field measurements and theoretical literature values. If the
calculated saturation is below the residual saturation, there is not likely a mobile LNAPL
phase and the LNAPL is likely not recoverable using fluid-pumping methods (TCEQ,
2003; API, 1999; Mercer and Cohen, 1990). The TCEQ 2003 guidance includes a set of
LNAPL recoverability graphs. The information required to use the graphs includes the
type of LNAPL, an estimate of the aquifer hydraulic conductivity, and an estimate of the
LNAPL thickness. The graphs show regions where LNAPL is likely recoverable and
where LNAPL is likely not readily recoverable. The graphs were developed using model
simulations and an assumption of a dual-pump system where LNAPL and groundwater
are recovered simultaneously. The user is cautioned to ensure that the assumptions
detailed in the TCEQ 2003 reference are applicable to the site before using the results of
the graphs.
It may also be useful to understand the natural attenuation of LNAPL. The chemical
composition and "finger print" analyses can be used to understand the volatile and
dissolution losses for LNAPL distribution to develop estimates of the loss rates from
these mechanisms. An understanding of the site-specific biodegradation by anaerobic
processes may also be factored into the natural attenuation estimates.
The mobility and recoverability of LNAPL can be estimated through the use of models.
Some of the more widely used models are the American Petroleum Institute (API)
LNAPL Distribution and Recovery spreadsheet models (API, 1999), API LNAPL
Dissolution and Transport Screening Tool (LNAST) model (API, 2002), and multiphase,
numerical, reservoir-simulation models. The user is cautioned that implementation of a
numerical simulation model requires extensive site data in order to run and calibrate the
model. The user is encouraged to begin with simple analytical tools and readily available
information and only to move to higher complexity modeling if the simpler solutions are
insufficiently discriminating for decision-making. For more information, see ASTM,
2000; API, 2002; DOE,1998; U.S. EPA, 1997a, and U.S. EPA, 2002.
In addition, if an LNAPL pumping system is currently operating at the site, as an interim-
recovery measure, then the volume recovered plotted as a function of time and a graph of
LNAPL recovery rate as a function of cumulative recovery can provide estimates of
LNAPL volume, recoverability, and remaining LNAPL. If the LNAPL recovery rate is
low or approaching a practical endpoint, then the LNAPL is approaching an immobile
state and further recovery through pumping methods is unlikely. Simulated graphs of
recovery rate and cumulative recovery are presented in Figures 2 and 3.
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Recovery Rate (gal/d)
Decline Curve Analysis
mnn n
ann n
RDD n
4nn n
onn n
n n
^^
^\^
^\
\
V
>
I
3.0E+05 5.0E+05 7.0E+05 9.0E+05 1.1E+06
Total Gallons
Figure 2. Hypothetical Decline Curve for an LNAPL Recovery System
Cumulative Total (gal)
1 9DF+nfi
I .^UC^UO
1 nnF+nfi
I .UUC^UO
C Q nnF+n^
o.uuc^uo
_o
O c nnp-i-n^
D.UUt+UO
"<5
"S 4 nnp+n^
,w t.UUCT^UO
9 nnF-i-nci
^.uuc^uo
Onnp-i-nn
Xr^'^ + " '
/
/
.uut+uu
Jul-98 Dec-99 Apr-01 Sep-02 Jan-04 May-05
Time
Figure 3. Hypothetical Cumulative Recovery for an LNAPL Recovery System
Targeted data collection can support the evaluation of viable LNAPL
management options and the selection of the most appropriate alternative for a
particular site.
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5.0 Review and Refine Conceptual Model, Long-Term Vision, and
Goals
The LNAPL Management Plan, including the conceptual model, long-term
vision, and goal, should be reviewed and refined based upon supplemental
data collected in the previous step. The stakeholder group should consider the
flexibility in the process to always base their decisions on the most up-to-date
information.
The conceptual model should be reviewed after the supplemental data have been
collected and analyzed in the previous step. If significant changes to the model or the new
risks have been identified, the stakeholder group should revisit the long-term vision and
goal presently being pursued. The iterative, flexible process should always utilize the best
information to support the decisions underway. This step provides a chance for the
stakeholder group to validate that the project is on course and that the goal and long-term
vision remain reasonable and practicable.
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6.0 Identify, Evaluate, and Select Management Options
The LNAPL management option, a critical component of the LNAPL
Management Plan, defines the alternatives for addressing LNAPL at a
particular site. Selection of the LNAPL management option requires an
understanding of LNAPL distribution, mobility, composition, and
recoverability. LNAPL management options include treatment, removal, and
containment technologies and institutional controls.
When an LNAPL management goal has been established by the stakeholder group and
supplemental data have been collected, LNAPL management options should be identified
and evaluated. It is important to the supplemental data collection process that potential
options available for LNAPL management be identified before the data-collection
process is finalized. The LNAPL management option may include one or a combination
of active recovery or treatment and passive treatment technologies, containment
technologies, and/or institutional controls. The LNAPL management option should also
consider current and potential future exposure scenarios and associated risks in the
selection of appropriate elements.
6.1 Identify and Evaluate LNAPL Management Options
The first step in developing the LNAPL management strategy is the identification and
selection of specific options that support the long-term vision. The range of possible
options includes active technologies, passive technologies, institutional controls,
engineering controls (i.e., containment) and combinations of these options. Evaluation of
active and passive technologies and engineering controls can be accomplished in several
phases, beginning with screening, followed by a more detailed evaluation based upon
specific criteria, and then, if necessary, laboratory or bench-scale tests, or field pilot tests.
The screening process is diverging, where as many options as possible are reviewed,
whereas the evaluation process is converging where the entire population of options is
examined in detail so that the most promising options can be identified using a set of
criteria developed for this specific site. Appendix C includes information on decision
criteria that can be utilized to select management options and a checklist of questions that
should be asked during the management-option step. The process may also include
iterative phases of supplemental data collection and technology evaluation.
The selection of a management option should consider the application of multiple
technologies and controls, either as a system or as a sequentially applied treatment train,
as well as the application of a single technology or control. Multiple technologies and
controls are often necessary to address different exposure pathways (e.g., hydraulic
pumping of LNAPL to reduce LNAPL mobility along with soil vapor extraction to
control volatile emissions near buildings). This strategic thinking should be considered
during the screening and selection of technologies and controls.
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6.2 Treatment, Removal, and Containment Technologies
A brief overview of various classes of technology and control options for addressing
LNAPL impacts is provided in this section. Various references provide a more
comprehensive review of active and passive technologies, including some examples
listed in Appendix D and specifically TCEQ, 2003; API, 1996a; API, 1999; and Bedient
etal., 1999; U.S. EPA, 1995.
Active treatment and removal technologies are typically used to reduce the mass of
LNAPL in the source area or the volume of mobile LNAPL. Examples of active
technologies follow.
Recovery of LNAPL by hydraulic pumping is the skimming or pumping of
LNAPL from wells or trenches under ambient pressure conditions. Groundwater
may also be recovered at the same well or trench in order to induce flow of
LNAPL to the recovery point by increasing the hydraulic gradient towards the
well. This type of LNAPL recovery has been widely practiced in the
environmental field; there are many references from which to gather more details
(API, 1996a; API, 1999; API, 2002; Bedient et al, 1999; Charbeneau, 2000).
Hydraulic recovery of LNAPL is suited to lighter petroleum products and
permeable hydrogeologic settings.
Bioremediation is a broad category of technologies that endeavor to enhance the
natural biological activity in the subsurface to reduce concentrations of COCs in
soil and groundwater. For petroleum-related COCs, most technologies include
introduction of oxygen and other nutrients, such as nitrogen and phosphorus, into
the subsurface. References for bioremediation applications include Hughes, 2002;
Bedient et al, 1999; NRC, 1994; NRC, 2000. Traditionally, bioremediation is not
attempted within the LNAPL; however this is an area of emerging technology
application; the user is encouraged to consult references for the most current
information.
Aggressive source-removal technologies are those that endeavor to significantly
reduce the mass of COCs in the subsurface by treating or removing LNAPL and
highest concentrations of COCs in soil and groundwater. Examples of aggressive
source-removal technologies include: soil vapor extraction, excavation, surfactant
flushing, steam stripping, electrical heating, chemical oxidation, and high-
vacuum, dual-phase extraction. Because a number of these technologies are
relatively new, the user is cautioned to research the latest information on the
technologies applicable for their specific problem. (API, 1996a; API, 2002;
Bedient et al, 1999; TCEQ, 2003; http://www.clu-in.org:
http://www.epareachit.org; http://www.gwrtac.org;
http ://www. groundwatercentral .info).
Engineering controls provide containment or isolation of the LNAPL to eliminate
exposure pathways. These systems generally are designed to be in-place for long periods
of time. Often they are used when available treatment or removal technologies are
infeasible or impractical. They can also be used when the site land use prohibits or
greatly restricts the opportunities for installation of active or passive technologies.
Examples of engineering controls that are applicable to LNAPL management include:
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Containment strategies, such as sheet piles, slurry walls, and hydraulic control
using various arrangements of pumping wells, involve physical barriers to flow.
These strategies are used when continued migration of a groundwater plume or
LNAPL as separate phase will result in unacceptable impacts to receptors. They
can also be used when source removal is not viable or when passive technologies
will not achieve the concentration reductions that are necessary to protect
receptors. The groundwater flow system and the hydrogeologic setting should be
well understood to implement effective containment systems. In fractured bedrock
or highly heterogeneous settings, containment systems are difficult to design and
operate. Containment strategies can be used for any type of LNAPL. However, it
is important to implement a monitoring program with the containment system to
ensure its reliable operation. Some containment systems have failed as a result of
poorly understood site conditions or temporal variations in site conditions that
were beyond the design basis for the containment system.
Passive treatment technologies are typically used to reduce concentrations of COCs
within the dissolved-phase groundwater plume. Passive technologies alone generally are
not appropriate for mobile LNAPL, but may have application for dissolved
concentrations resulting from residual LNAPL. For some LNAPL sites, a combination of
an active source-zone technology and a passive dissolved-phase groundwater plume
technology may be appropriate. Examples of passive technologies include the following:
Monitored natural attenuation (MNA) is a biodegradation process where the
natural biological activity, as well as the other attenuation mechanisms such as
dispersion, is monitored carefully to predict and evaluate the reduction in
concentrations of COCs in groundwater. The applications for MNA include the
lighter petroleum hydrocarbons, particularly in the distal portion of the dissolved
plume. Natural conditions that are conducive to degradation are important for
MNA to be successful (API, 1997; API 1997a; http://www.clu-in.org: U.S. EPA,
1999).
Permeable reactive barriers are groundwater interceptor trenches that are filled
with one or more materials that degrade, adsorb, or chemically alter the COCs in
the groundwater. The reactive barriers may be applied in higher permeability
groundwater zones that are relatively homogeneous down-gradient of the LNAPL
plume. This is because the treatment of the dissolved COCs in groundwater
depends upon the impacted groundwater flowing through and contacting the
interceptor trench materials and it is not desirable for LNAPL to flow through the
reactive media in the trench (http://www.clu-in.org).
Institutional controls are management options that reduce or remove the likelihood of
exposure for a receptor through control of the land use or activities conducted on the
property impacted by LNAPL and COCs in soil and groundwater. Institutional controls
include restricting activities on a property (e.g., industrial uses). The restrictions can be
implemented for example by using deed restrictions, deed notices, and zoning.
Institutional controls should be integrated into the overall LNAPL Management Plan and
may likely be required along with the passive or active technologies (U.S. EPA, 2003).
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6.3 Select and Test Technology
Initially management options are screened using a set of criteria that reflect back to the
goal previously agreed upon and the improved technical understanding of LNAPL
distribution and behavior provided by the supplemental data collection. The screening
process allows for comparison of various LNAPL reduction, recovery, and management
alternatives. The process begins with development of screening criteria to compare
alternative technologies for their suitability to the specific LNAPL conditions at the site
(based on the LNAPL investigation results), their predicted ability to achieve the
established goal, and their cost. The screening process supports the identification of the
highest-benefit alternatives to meet the long-term vision, or highlights the need for
additional data collection and evaluation. Additional information about decision criteria
for the management-option selection process, including the potential trade-offs between
short and long-term costs and performance of different technologies, is included in
Appendix C.
Based on the screening and additional LNAPL investigation results, a more detailed
analysis of the most promising technologies can be conducted. Laboratory, bench-scale,
or pilot testing and computer modeling may also be recommended before full-scale
implementation of one or more technologies selected as a result of the screening and
detailed analysis.
As part of the evaluation process, these important questions should be addressed:
Are there off-site releases of NAPL COCs?
Should a phased or treatment-train approach be used (e.g., active technology
followed by passive technology)?
Is treatment preferred over engineering (e.g., hydraulic containment) or
institutional controls (e.g., environmental covenant or deed restriction)?
Can engineering or institutional controls be used as part of a combined strategy
with active measures?
Are there time constraints related to redevelopment, compliance or other issues
that may affect the technology selection?5
How long will it take to meet the endpoints and eventually, the goal? Include
some assessment of the uncertainties associated with each evaluation.
Are there surface disturbance restrictions and access issues that should be
addressed?
How can the LNAPL-recovery effort be integrated with existing or envisioned
property-use plans?
Are there other impediments that might influence technology selection?
5 It must be noted that there are potentially large uncertainties in the estimation of the time required to reach the
endpoints with any particular technology (U.S. EPA, 2001). It may also be desirable to consider the various
technologies in terms of their relative times to reach endpoints, rather than to focus on the absolute estimate of time for
any one technology.
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Will removal of LNAPL have a measurable impact on COC concentrations in
other media?
Will removal of LNAPL make the site more appealing for reuse?
What impact will removal of LNAPL have on the overall site remediation
timeframe?
If physical controls are chosen as an alternative to recovery, what will happen if
the control strategy fails?
During the technology-selection process, feasible technologies are evaluated based on the
capability and likelihood of meeting the established goal. Consideration of the limitations
of the technology should be evaluated prior to selection. The goal may need to be revised
based on the capabilities of the technology. Specific LNAPL investigation results and
management options will provide a basis for identification of data that should be
collected to measure progress. Appendix C includes additional information about the
management-options selection process and criteria for selection.
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7.0 Define Endpoints and Develop Contingency Plan
Specific endpoint(s) must be defined for each goal. The endpoints provide a
tool or metric to measure performance and relate that criterion to a specific
goal. A contingency plan should also be developed, so that it can be
implemented if endpoints cannot be achieved. Management options may be
revisited and revised, if necessary.
The establishment of LNAPL management goals for a site involves development of an
overall strategy or roadmap that includes multiple phases and activities that support each
of the phases, as described in Section 3.0. After the goal is established for a particular
phase of the project, the stakeholder group should agree upon endpoints, which are
specific, measurable criteria that demonstrate progress toward achieving the goal.
Information regarding the establishment of endpoints should then be communicated to
the broad stakeholder community so all are clear as to what will be accomplished when
endpoints are achieved.
Endpoints are defined after an accurate understanding of the LNAPL distribution and
behavior has been reviewed and technologies to address the LNAPL have been selected.
Individual endpoints should be established for each phase of the LNAPL Management
Plan. For example, an intermediate-performance goal might be LNAPL source-area
recovery, through installation of a steam-injection system. The associated endpoint might
be a targeted cumulative recovery within a specified length of time.
Endpoints may be performance-based specific to the remedial technology (such as
removal of "x" amount of LNAPL) or may reflect a measurable long-term condition,
such as a specific hydrocarbon concentration in soil or groundwater. An endpoint may
also be identified to track progress on the management of dissolved plumes that remain
after active management of the LNAPL phase has concluded.
Endpoints should be established for active, passive, and engineering-control systems at
various points along the "path to closure." Final endpoints should be established as
criteria for achieving closure for sites (i.e., "closure criteria). Stages for endpoint setting
include:
installation or operation of active or passive technologies and institutional or
engineering control,
discontinuation or modification of a system,
initiation or conclusion of monitoring for stability, and
final closure.
Specific examples of endpoints include:
recovery rate for an LNAPL recovery system is reduced to an established value
(e.g., three gallons per day);
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specific COC in LNAPL is reduced to a target value at "x" monitoring locations
over "y" period of time;
stability of the dissolved-phase plume is demonstrated based on a dissolved COC-
concentration threshold at "x" monitoring locations over "y" period of time;
LNAPL transmissivity is reduced to a certain value at "x" monitoring locations;
LNAPL saturations at all points within the area of distribution have been reduced
to levels below residual saturation, as measured by "a" method and cross-checked
with "b" method;
groundwater samples from "xx" monitoring wells did not contain LNAPL-related
organic constituents at concentrations above drinking-water maximum
contaminant levels (MCLs) for four consecutive quarterly monitoring events;
LNAPL chemistry has been changed so it no longer contains VOCs at measurable
concentrations using analytical method "d" and vapor concentrations in the
vadose zone measured by method "e" are below measurable levels;
a containment system meeting "g, h, i" specifications has been installed and tested
for integrity;
final relative permeability value is attained.
A critical endpoint that should be established involves the suspension of active
technologies. Examples of such an endpoint might measure some component of LNAPL
mobility or "x" volume recovered over a certain area, an alternative concentration limit
within specific monitoring wells on the property, or a soil-concentration standard over a
certain area of the site.
Endpoints should be defined with specific considerations including:
type of measurement
method for sample collection
analytical method
location of measurement, (including point of compliance)
the timeframe for measurements
number of measurements
data analysis, statistical evaluation, and data presentation.
The more specifically the endpoints are defined the less likelihood there will be cause for
confusion or dissension among the various stakeholders.
Significant uncertainties are associated with natural systems. Design and implementation
of engineered systems to contain or remediate these natural systems are also associated
with significant uncertainties. These uncertainties must be acknowledged through the
evaluation of knowledge gaps and the development of contingency plans to enable
meeting of the endpoints. The contingency plan should describe the possible causes for
"failure" and appropriate response actions for each. It should be flexible enough that it
allows revisiting of management options, including modifications, upgrades and new
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systems, if needed, long-term vision and goals, and collection of supplemental data, if
necessary.
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8.0 Implement and Monitor Performance
Implementation of the LNAPL management strategy will occur in phases,
near-term, intermediate, and long-term, as specific goals are addressed.
During implementation, monitoring of the performance of the management
options selected should be initiated so that progress towards meeting the
endpoints and goals can be measured at some reasonable time thereafter.
The first step in implementation should be preparation of a detailed design for the
selected management/technology option. The detailed design may be based upon the
results of bench and/or pilot-scale testing, recommended to ensure optimization of the
remediation process and reduction of uncertainties associated with the process. In some
cases, the selected management/technology option may involve a phased or treatment-
train approach (e.g., active technology followed by passive technology). Monitoring will
thus need to be tailored to each phase of the project. Performance monitoring is
conducted at regular intervals during operation of active remediation systems to track
progress towards achieving the endpoints and to determine when active system
operations can be suspended. Compliance monitoring is conducted following system
shutdown to track progress of the passive technologies towards achieving an LNAPL
management goal. If only active remediation is involved, confirmation monitoring will
generally be required to monitor for rebound effects that may occur after system
shutdown.
Both the Performance Monitoring Plan and the Compliance Monitoring Plan should be
completed and agreed to by the stakeholders before implementation is initiated. If written
reports are prepared, they should be provided to the stakeholder group with sufficient
time for their review. When performance-monitoring data demonstrate that specific
endpoints have been attained, approval may be given to suspend the active phase of
LNAPL management and confirmation monitoring may begin. Once confirmation
monitoring demonstrates that the LNAPL management goal has been achieved, approval
may be given to close the site (if these were the final corrective measures), or the project
may move into the next phase.
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9.0 Evaluate Progress
Progress towards meeting endpoints, goals, and long-term vision is
measured using the data collected during implementation and monitoring.
As data are collected on the effectiveness of the LNAPL management
option, progress should be evaluated. If satisfactory progress is not being
made, a contingency plan, which may include enhancements to the current
system or selection of an alternative system, should be implemented.
The LNAPL Management Plan is revisited as new information is collected. A series of
questions regarding progress with regards to endpoints, goals, and long-term vision are
asked (Figure 1).
Has the endpoint been achieved?
If yes, then perform confirmation monitoring to assess whether the goal has
been achieved.
If yes, then assess whether this was a final goal, implying that the long-
term vision has been achieved. If yes, then the process ends.
If no, is the management option on track to meet the goal. If yes, continue
to implement and monitor. If no, implement contingency plan.
If no, is the management option on track to meet the endpoint?
If yes, continue implementation and monitoring.
If no, implement the contingency plan.
During definition of endpoints, a contingency plan should have been developed (Section
7.0). The contingency plan should be implemented if the management option is not on
track to meet the endpoints or goals. Depending upon the specific situation, the
contingency plan may require:
1) review and selection of alternative management options (Section 6.0)
2) modifications or upgrades to the current management system (Section 6.0)
3) collection and analysis of supplemental data (Section 4.0) or
4) revisiting long-term vision and goals (Section 3.0).
The LNAPL Management Plan comprises the collected understanding and desires of the
stakeholder group that relate to the ultimate condition of the property. The LNAPL
Management Plan begins with the current understanding of site conditions and progresses
to a long-term vision, where appropriate science and engineering have been utilized to
bring the site to a condition that protects human health and the environment to a
reasonable and practicable level.
It is crucial to the success of the overall project that all of the stakeholders keep that long-
term vision in-mind when working through the intermediate activities. This means that
the long-term focus for the plan and the elements that define success for the stakeholders
should be clearly articulated and the vision shared among all of the stakeholders. This
may be accomplished with a document that is referenced and updated throughout the
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intermediate steps, or with another tool such as a series of documents, a section in a
regulatory submittal, presentations, or web pages that communicates the common
understanding developed by the stakeholder group.
The flexible, iterative process for LNAPL management ensures that the decisions at each
step in the process are made using the latest information collected. The understanding of
site conditions, the vision, goals, and endpoints in the document should be re-visited by
the stakeholders at each major step and revised as necessary to reflect the current state of
knowledge and the current preferences of the stakeholders. All changes should be
documented and the broad stakeholder community should be notified if a revision has
been completed.
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Appendix A: Current Conditions Checklist
This checklist provides a detailed list of information and data that are most often needed
to develop an LNAPL Management Plan. Not all of the information will be available for
every site and not all of the information will be needed for every site. The first section
covers general topics that include regulatory requirements, schedule, etc. The second
section focuses on the current LNAPL management program, including site conditions.
Topic
Regulatory Setting
Specific legal and regulatory authorities (e.g.,
Resource Conservation and Recovery Act
(RCRA), state groundwater program, state
voluntary action program, etc.)
RCRA Environmental Indicators, if applicable
1 ml points previously defined (on site; off-site)
Measurement/monitoring requirements
Schedule
Current county and local LNAPL-related
requirements, if any (zoning, land use plan, etc.)
Related issues (e.g., participation in voluntary
program, permit requirements, consent decree,
judicially imposed requirements, stakeholder
information, etc.)
COCs in soil, groundwater or other
environmental media that may need to be
addressed
Status
c
i
NA
Description/Comments
C = Complete
I = Incomplete
NA = Not Applicable
Current LNAPL Management Program
Existing LNAPL management philosophy/approach
Current monitoring/characterization approach
Stabilization to prevent migration (e.g., by
pumping, barriers, etc.)
Control at the site's perimeter
Recovery underway for source control to reduce
plume's mass and volume
Other engineering controls
Data Available
Yes
No
Data Sufficient
Yes
No
Description, Comments
Site Conditions
Hydrogeologic Setting
Depth to and elevation of LNAPL and affected
groundwater
Hydraulic gradient and direction of flow of
groundwater and LNAPL
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Current LNAPL Management Program
Potential for direct contact with LNAPL during
excavation and proximity to underground
structures and utilities
Fluctuating groundwater elevation
Seasonal or temporal fluctuations in
groundwater elevation can result in residual
LNAPL in pores in a smear zone and "pockets"
of LNAPL trapped below the water table
Groundwater classification system
If there is a groundwater classification system, it
may have requirements for LNAPL removal and
may impact LNAPL management goals
Proximity to surface water
Potential influence of surface water on
groundwater movement (e.g., aquifer receiving
recharge from or discharging to surface water)
Potential impact of LNAPL on receiving surface
waters
Surface cover
The type and permeability of surface cover
influences the rate and amount of surface-water
infiltration (and distribution and dissolution of
LNAPL) in the source area)
Data Available
Yes
No
Data Sufficient
Yes
No
Description, Comments
Geologic Setting
Unconsolidated deposits
Texture of sediments, e.g., sands, silts, and clays
Complexity of stratigraphy, vertically and
laterally (i. e. heterogeneity)
Consolidated materials
Fractured or karst bedrock may be complicating
factors in prediction of LNAPL behavior
Complexity of stratigraphy, vertically and
laterally (i. e. heterogeneity)
Lithologic properties affect the distribution,
mobility, and recovery of LNAPL
Lithologic properties in the interval that
contains LNAPL (e.g., grain-size distribution,
porosity, effective porosity, hydraulic
conductivity, etc.)
Scale issue is important for designing/collecting
and understanding field measurements, i.e. site-
scale, and for determining sampling location for
point measurements to be made in the field, or
for samples to be taken for laboratory analyses
Subsurface LNAPL Distribution
Major LNAPL sources, release sites
Identification of facility areas and operations
contributing to LNAPL source areas, including
underground utilities
General boundaries of the area where LNAPL
was released to the subsurface
At a large facility, source areas will likely
encompass multiple, separate-release incidents
Estimated volumes (Note: accurate volume
estimates are very difficult to obtain for a number
of reasons)
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Current LNAPL Management Program
Based on records of release incidents
Field measurements (i.e., LNAPL thickness)
Innovative field screening techniques (e.g., LIF-
based cone penetrometer)
Results will generally be a weight-of-evidence
estimate with uncertainty bounds
Type of LNAPL
Complex facilities likely have LNAPL with
different characteristics at different locations
Fate and transport properties and potential to
contribute COCs to a dissolved-phase plume or
volatilized in vadose zone
Potential for LNAPL to be an ongoing source of
COCs
Focus is on LNAPL, which can float on the
water table; for releases of dense NAPL
(DNAPL), additional resources should be
consulted6. Potential for some petroleum
hydrocarbons to be DNAPL (e.g., lube oils) but
their mobility, viscosity, solubility and COC
content will make them easier to detect than for
other types of DNAPL (e.g., chlorinated solvents
LNAPL constituents and COCs
Data Available
Yes
No
Data Sufficient
Yes
No
Description, Comments
Smear Zone
Depends on the hydrogeologic regime,
climatologic factors
May be a source of vapor and dissolved-phase
exposure pathways
Above and below the water table, variable LNAPL
saturations
Estimates of saturations at various points
throughout the LNAPL based on field
measurements
Potential for Future Releases
Important for operating facilities
Not an issue for closed facilities, or facilities to be
closed unless tanks, vessels, and piping still contain
LNAPL
Could significantly impact LNAPL management
strategy
Measurement Tools to Characterize LNAPL
Distribution
Conventional measures (e.g., soil cores, borings,
monitoring wells)
Define methods, brief description of application,
strengths, weaknesses, etc.
Innovative measures (e.g., Rapid Optical Screening
Tool (ROST, cone penetrometer (CPT), Laser
Induced Fluorescence (LIF), LNAPL Ribbon
Sampler, GeoVis (a CPT-mounted imaging
system), Membrane Interface Probe (MIP), etc.
Define methods, brief description of application,
strengths, weaknesses, etc.
' See the Reference Section for selected sources of information of DNAPLs.
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Current LNAPL Management Program
Appropriate methods and utility of methods for
estimating the location, saturation, etc, of
LNAPL in the subsurface will depend on site
conditions and LNAPL properties
Core and fluid analysis (fluid density, viscosity,
interfacial tension, soil-fluid interaction properties
including intrinsic permeability, capillary pressure and
relative permeability)
Data Available
Yes
No
Data Sufficient
Yes
No
Description, Comments
Known Fluid Properties Groundwater and
LNAPL
Current NAPL characteristics (e.g., vapor pressure,
boiling point, distillation curve)
May be estimated based on literature values, or
on a number of field samples throughout the
LNAPL
Characteristics change with time as the LNAPL
ages in the environment
Fluid properties that influence mobility and
recoverability (e.g., viscosity, density, interfacial
tension)
Literature and calculated values based on
specific LNAPL characterization
Important parameters in design and analysis of
LNAPL remediation systems
Potential COCs released by LNAPL
The COCs (including breakdown products) that
can be released by a LNAPL plume will provide
information as to the potential for the LNAPL
plume to act as an ongoing source of COCs to
groundwater
History of Plume Extent (liquid and dissolved
phases)
What are plume dimensions over time?
Provides anecdotal information concerning the
mobility of the LNAPL and dissolved plumes
(e.g., stable, shrinking, growing)
Potential for future releases
How has the assessment program impacted plume
definition?
Are there areas for which no information is
available?
Can the downgradient extent of the LNAPL be
monitored with an existing sampling network?
Are the measurement methods used effective for
LNAPL characterization?
How have historical water-table elevations
impacted plume definition?
Provides an indication of the impact of the
smear zone and possible submerged "pockets"
of LNAPL on the dissolved plume
Have models been run?
What types of models analytical or numerical?
What were the modeling results?
Do field data support the predictions? What are
the shortcomings of the models?
Recovery History
LNAPL recovery history and significant aspects of
the program (graphs)
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Current LNAPL Management Program
Methods for recovery, time line, number of wells
May include a narrative, volume vs. time graphs
Qualitative and quantitative information
Operational history and effectiveness
Problems with recovery system can indicate
potential long-term ineffectiveness of system,
e.g., technology limitations or system location
relative to mobile LNAPL
Historical and current recovery rate provide an
indication of the potential for ultimate LNAPL
recovery, recovery efficiency, and practical
endpoints
Inference of LNAPL transmissivity
characteristics, site-scale or aggregate
recoverability of the LNAPL
Data Available
Yes
No
Data Sufficient
Yes
No
Description, Comments
Existing and Potential Off-Site Impacts
Factors that affect LNAPL management
Potential for vadose-zone vapors, ground-water
dissolved phase, and LNAPL migration
Potential impact locations
Adjacent natural environments and resources
(e.g., ecological habitats)
Discharge to surface water (e.g., rivers,
streams, wetlands)
Discharge to subsurface (e.g., water-supply
aquifers)
Adjacent man-made structures (e.g., buildings)
Other (e.g., utility corridors)
Land Use and Ownership
Petroleum facility
Adjacent properties potentially affected
Surrounding area land uses
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50
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Appendix B: Potentially Affected Interests Matrix
! f
1 r
I I'
i *
ii!
51
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Appendix C: Selection ofLNAPL Management Options
Decision Criteria
EPA and many state agencies have identified decision criteria for selection ofLNAPL
management options (U.S. EPA, 2002; U.S. EPA, 1997a; ASTM, 1995; ASTM, 2000).
These criteria are intended to reflect the values of the decision makers. The criteria that
are used to decide which alternative has the highest net benefit include the following:
protection of human health and the environment
probability that goal will be met
technology effectiveness and associated time frame
appropriate technology for short-, intermediate-, or long-term remedial action
stakeholder acceptability (tie to the goal agreed to by the stakeholder group)
regulatory compliance (e.g., applicable or relevant and appropriate requirements
[ARARs], state cleanup standards)
implementability
technical practicability
reliability and maintainability
long and short-term risks in implementing the technology
cost-effectiveness of the technology
technology maturity (proven performance or emerging technology)
institutional issues and long-term controls as they affect technology
implementation
time constraints
current and future land use.
Typically in a decision process a sub-set of these criteria will be used to evaluate the
various available alternatives. It is likely that all of the decision criteria are not equally
valued and therefore weighting factors would be applied to each of the criteria in order to
reflect the priorities of the decision makers. The decision criteria must reflect the values
of all of the stakeholders and therefore the decision criteria should be developed as part
of the consensus process.
LNAPL Management Options Checklist
A checklist of questions to support the selection ofLNAPL management options follows.
In addition to the issues raised in Section 4, the following more detailed questions should
be addressed during the technology-selection process.
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(Questions
rTow mobile is the LNAPL with respect to recovery or
containment?
W hat field evidence exists to support the stability of the
LNAPL distribution or potential for migration of LNAPL?
rTave data been collected on LNAPL and site properties (e.g.,
viscosity, LNAPL saturation, relative permeability)?
rTow likely is it that excavation and other construction
activities will impact or be impacted by residual or mobile
LNAPL?
rTow accessible is the LNAPL (e.g., depth, surface activity)?
rTow maintainable are institutional and engineering controls
into the future? Is there a time limitation to the effectiveness of
institutional or engineering controls (e.g., closure and transfer
of the site in the future)?
Ohould there be a contingency for addressing change in status
of the site?
Consider variability across the site. Are samples
representative of the site as a whole?
Is it helpful to understand the process of COC dissolution
from the LNAPL, if meeting drinking water maximum
contaminant levels (MCLs) is an issue or goal? If control of
the down-gradient dissolved plume is a goal for the overall site
remedial action, then a site-specific understanding of the
release of specific COCs from the LNAPL is important.
Are vapors an issue (with respect to LNAPL present or
remaining) after endpoints are achieved?
Lyoes the management option reduce risks, under both current
and potential future exposure scenarios?
L^an the LNAPL be treated in place to reduce/remove COCs
and so reduce toxicity to an acceptable level?
L^an the LNAPL Management Plan meet
regulatory /stakeholder requirements and concerns?
Answers
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Appendix D: Selected LNAPL Characterization and Remediation
Technology Publications
General Information Sources
1. American Petroleum Institute (API) - http://www.api.org, LNAPL Resource Center
link, catalog link, http://api-ep.api.org/filelibrary/ACFDA.pdf, and API Soil and
Groundwater Research Bulletins link http://api.org/bulletins.
2. The Association for Environmental Health and Sciences (AEHS) TPH Working Group
Series
http ://www. aehs. com/publications/catalog/contents/tph.htm
3. ASTM International website - http://www.astm.org.
4. ASTM, 2000. Standard Guide for Risk-Based Corrective Action. Publication E2081-
00. American Society for Testing and Materials, West Conshohocken, PA.
5. ASTM, 2003. Standard Guide for Developing Site Conceptual Models, Publication
E1689-95(2003)el. American Society for Testing and Materials, West Conshohocken,
PA.
6. ASTM 1995. Standard Guide for Risk-Based Corrective Action Applied at Petroleum
Release Sites, Publication E1739-95. American Society for Testing and Materials, West
Conshohocken, PA.
7. Beckett, G.D., 2000. Remediation is Enhanced Oil Recovery: Know Your Source.
AAPG & SPE Convention, Long Beach, California, June 2000.
8. Beckett, G.D., D. Huntley, 1998. Soil Properties and Design Factors Influencing Free-
phase Hydrocarbon Cleanup. January 1998, Environmental Science and Technology.
9. Beckett, G.D., D. Huntley, 1994, The Effect of Soil Characteristics on Free-Phase
Hydrocarbon Recovery Rates: Proceedings of the Petroleum Hydrocarbon and Organic
Chemicals in Ground Water, Houston, Texas, NGWA, API, November 2-5, 1994.
10. Environment Canada Oil Properties Database
http://www.etcentre.org:8080/cgi-win/OilPropspill e.exe?Path=\Website\river\
11. Environmental Security and Technology Certification Program Web Site -
http://www.estcp.org and technical documents list,
http://www.estcp.org/documents/techdocs/index.cfm
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12. Federal Remediation Technologies Roundtable (FRTR) Web Site -
http://www.frtr.gov, FRTR Cost and Performance Report link at
http://www.frtr.gov/costperf.htm, and LNAPL/DNAPL recovery optimization documents
at http://www.frtr.gov/optimization/treatment/insitu.html#lnapl
13. Groundwater Central Portal - Groundwater technology information portal for web-
based information. Search engine is populated with a substantial number of documents
related to LNAPL at http://www.groundwatercentral.info
14. Ground-Water Remediation Technologies Analysis Center (GWRTAC):
http://www.gwrtac.org
15. Huntley, D., G.D. Beckett, 2002. Persistence of LNAPL Sources: Relationship
Between Risk Reduction and LNAPL Recovery. Journal of Contaminant Hydrology, Vol.
59, Issues 1-2, pgs. 3-26, November 2002.
16. Interstate Technology and Regulatory Council (ITRC) Web Site -
http ://www.itrcweb .org
17. Lundegard, P.O., G.D. Beckett, 2000. Practicability of LNAPL Recovery -
Implications for Site Management. Battelle 2nd International Conference on Remediation
of Chlorinated and Recalcitrant Compounds, Monterey, CA, May 2000.
18. National Academy of Sciences. National Research Council: http://www.nas.edu
19. Remediation Technologies Development Forum (RTDF) NAPL Cleanup Alliance
Web Site - http://www.rtdf org/public/napl/
20. Texas Natural Resources Conservation Commission Publications Search Page
http://www.tnrcc.state.tx.us/admin/topdoc/
21. United States Environmental Protection Agency (U.S. EPA) Technology Innovative
Program Websites: http://www.epa.gov/swertio 1/about.htm, http://www.clu-in.org,
http://www.epareachit.org, and Technology Focus area, http://www.clu-in.org/techfocus/
for Air Sparging, Bioventing/Biosparging, Ground-Water Circulating Wells, Multi-Phase
Extraction, Natural Attenuation, and Soil Vapor Extraction, especially
Engineering/Regulatory Guidance categories for each topic.
22. U.S. EPA, Office of Underground Storage Tanks, Publications Page at
http ://www. epa. gov/swerust 1 /pub s/index. htm
Characterization, Monitoring, Fate and Transport Publications
1. Abdul, A.S., S.F. Kia, and T.L. Gibson, 1989. Limitations of Monitoring Wells for the
Detection and Quantification of Petroleum Products in Soils and Aquifers, Ground Water
Monitoring Review, 9(2): 90-99.
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2. API, 1996. Compilation of Field Analytical Methods for Assessing Petroleum Product
Releases. American Petroleum Institute, Publication 4635. Washington, DC.
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
3. API-LNAST Software Download Page
http://www.aquiver.com/1987bl.htm
4. Beckett, G.D, and S. Joy, 2003. Light Non-Aqueous Phase Liquid (LNAPL)
Parameters Database - Version 2.0 - Users Guide. American Petroleum Institute,
Publication 4731. Washington, DC, December 2003.
http ://groundwater. api. org/lnapldatabase/
5. Beckett, G.D., D. Huntley, 1997. Hydrocarbon Fate and Transport Predictions: When
Are One-dimensional Solute Transport Calculations Valid? (Updated). AEHS West Coast
Annual Convention, Oxnard, CA, March 1997.
6. Beckett, G.D., D. Huntley, M.P. Wiedlin, 1996. Hydrocarbon Fate and Transport
Predictions: When Are One-dimensional Solute Transport Calculations Valid? AAPG
Annual Convention, San Diego, California, May 1996.
7. British Petroleum, 2003. FPH Baildown Test Procedures: Field Analysis. Global
Environmental Management Company, a BP Affiliated Company. Naperville, IL.
8. Charbeneau, R.J., 2003, Models for Design of Free-Product Recovery Systems for
Petroleum Hydrocarbon Liquids. American Petroleum Institute, Publication 4729.
Washington, DC, August 2003.
http ://groundwater. api. org/lnapl/
9. Charbeneau, R., 2000. Groundwater Hydraulics and Pollutant Transport. Prentice-Hall,
Inc. Upper Saddle River, NJ.
10. Edwards, D.A., M.D. Andriot, M.A. Amoruso, A.C. Tummey, CJ. Bevan, A. Tveit,
L.A. Hayes, S.H. Youngren and D.V. Nakles, 1997. Volume 4: Development of Fraction
Specific Reference Doses (RfDs) and Reference Concentration (RfCs) for Total
Petroleum Hydrocarbons (TPH). The Association for Environmental Health and Sciences
(AEHS), ISBN 1-884-940-13-7, Amherst, MA.
http://www.aehs.com/publications/catalog/contents/Volume4.pdf
11. Farr, A.M., RJ. Houghtalen, and D.B. McWhorter, 1990. Volume Estimation of
Light Nonaqueous Phase Liquids in Porous Media, Ground Water, 28(1): 48-56.
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12. Gustafson, 1, J. Griffith Tell, and D. Orem, 1997. Volume 3: Selection of
Representative TPH Fractions Based on Fate and Transport Considerations. The
Association for Environmental Health and Sciences (AEHS), ISBN 1-884-940-12-9,
Amherst, MA.
http://www.aehs.com/publications/catalog/contents/Volume3.pdf
13. HSSM-Hydrocarbon Spill Screening Model, 1997, Windows Version 1.20a,
September 1997.
http://www.epa.gov/AthensR/hssml.htm
http://www.epa.gov/ada/csmos/models/hssmwin.html
14. Huntley, D., G.D. Beckett, 1997. The Life and Times of LNAPL Pools. An
investigation into the lifespan and time-dependent magnitude of dissolved-phase impacts
from free-phase hydrocarbon pools. AEHS West Coast Annual Convention, Oxnard, CA,
March 1997.
15. Potter, T. and K.E. Simmons, 1998. Volume 2: Composition of Petroleum Mixtures.
The Association for Environmental Health and Sciences (AEHS), ISBN 1-884-940-19-6,
Amherst, MA.
http://www.aehs.com/publications/catalog/contents/Volume2.pdf
16. Sale, T., 2001. Methods for Determining Inputs to Environmental Petroleum
Hydrocarbon Mobility and Recovery Models. American Petroleum Institute, Publication
4711. Washington, DC, July 2001.
http://api-ec.api.org/filelibrary/4711 .pdf
17. Texas Commission on Environmental Quality (TCEQ) 2003. NAPL Evaluation and
Recovery. TRRP-32 Guidance Document. Draft 8, Austin, TX. Texas Natural Resources
Conservation Commission Publications Search Page at
http://www.tnrcc.state.tx.us/admin/topdoc/
18. U.S. EPA, 1995. Groundwater Issue: Light Non-Aqueous Phase Liquids, EPA/540/S-
95/500, EPA ORD, OSWER, Washington, DC.
http://www.epa.gov.ada.download/issue.lnapl.pdf
19. Vorhees, D., J. Gustafson, and W. Weisman, 1999. Volume 5: Human Health Risk-
Based Evaluation of Petroleum Contaminated Sites: Implementation of the Working
Group Approach. The Association for Environmental Health and Sciences (AEHS),
ISBN 1-884-940-12-9, Amherst, MA.
http://www.aehs.com/publications/catalog/contents/Volume5.pdf
20. Weisman, W., 1998. Volume 1: Analysis of Petroleum Hydrocarbons in
Environmental Media. The Association for Environmental Health and Sciences (AEHS),
ISBN 1-884-940-14-5, Amherst, MA.
http://www.aehs.com/publications/catalog/contents/Volumel.pdf
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21. Wiedemeier, T., M.A. Lucas, and P.E. Haas, 2000. Designing Monitoring Programs
to Effectively Evaluate the Performance of Natural Attenuation, Air Force Center for
Environmental Excellence, Technology Transfer Division, Brooks Air Force Base, San
Antonio, TX, January 2000 at
http://www.afcee.brooks.af.mil/er/ert/download/DesignMonProgs.pdf
22. Zhendi, W., B.P. Hollebone, M. Fingas, B. Fieldhouse, L. Sigouin, M. Landriault, P.
Smith, J. Noonan, and G. Thouin, 2003, Characteristics of Spill Oils, Fuels, and
Petroleum Products: 1. Composition and Properties of Selected Oils, U.S. Environmental
Protection Agency EPA/600/R-03/072, Research Triangle Park, NC, July 2003.
http://www.epa.gov/athens/publications/reports/EPA-600-R03-072-OilComposition.pdf
Air Sparging, Soil Vapor Extraction, Bioventing Publications
1. API, 1995. In Situ Air Sparging: Evaluation of Petroleum Industry Sites and
Considerations for Applicability, Design, and Operation. American Petroleum Institute,
Publication 4609. Washington, DC, May 1995.
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
2. Beckett, G.D., 2000. Soil Vapor Extraction under Capped and Uncapped Surface
Conditions. Geotechnical Fabrics Review; Vol 18, No. 4.
3. Beckett, G.D., D.A. Benson, 1996. Diffusion Limited Soil Vapor Extraction: Geologic
and Bed Thickness Controls. AAPG Annual Convention, San Diego, CA, May 1996.
4. Beckett, G.D., D. Huntley, S. Panday, 1995. Air Sparging: A Case Study in
Characterization, Field Testing, and Modeling Design. Proceedings of the Petroleum
Hydrocarbons and Organic Chemicals in Ground Water: Prevention, Detection and
Restoration, Houston, NGWA, API, November 1995.
5. Beckett, G.D., D. Huntley, 1994, Characterization of flow parameters controlling soil
vapor extraction: Ground Water, Vol. 32, No. 2, pp. 239-247.
6. ESTCP, 2004, Natural Pressure-Driven Passive Bioventing, CU-9715, Environmental
Security Technology Certification Program, Washington, DC, January 2004.
7. ESTCP, 2002. Cost and Performance Report: Multi-Site Air Sparging, CU-9808,
Environmental Security Technology Certification Program, November 2002.
http://www.estcp.org/documents/techdocs/199808.pdf
8. Leeson, A., P.C. Johnson, R.L. Johnson, C.M. Vogel, R.E. Hinchee, M. Marley, T.
Peargin, C.L. Bruce, I.L. Amerson, C.T. Coonfare, R.D. Gillespie, andD.B. McWhorter,
2002. Air Sparging Design Paradigm, Battelle, August 2002.
http://www.estcp.org/documents/techdocs/Air Sparging.pdf
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9. NFESC, 2001. Air Sparging Guidance Document, NFESC Technical Report TR-2193-
ENV, Battelle for Navy Facility Engineering Service Center, Port Hueneme, CA, August
31,2001.
http://enviro.nfesc.navy.mil/erb/erb a/restoration/technologies/remed/phys chem/tr-
2193-air-sparg.pdf
10. U.S. Army Corps of Engineers, 1997. Engineering and Design: In-Situ Air Sparging,
EM 1110-1-4005, Engineer Manual, U.S. Army Corps of Engineers, September 15, 1997.
http://www.usace.army.mil/inet/usace-docs/eng-manuals/emlllO-l-4005/toc.htm
11. U.S. EPA, 1995. Bioventing Principles and Practices, EPA/540/R-95/534a, U.S. EPA
Office of Research and Development, Washington, DC, September 1995 at
http://www.epa.gov/ORD/WebPubs/biorem/ibiov.pdf
12. U.S. EPA, 2001. Development of Recommendations and Methods to Support
Assessment of Soil Venting Performance and Closure, EPA/600/R-01/070, U.S. EPA
Office of Research and Development, Washington, DC, September 2001 at
http://www.epa.gov/ada/download/reports/epa 600 rOl 070.pdf
13. WASTECH, 1998. Innovative Site Remediation Technology: Design and
Application, Volume 7, Vacuum Extraction and Air Sparging, American Academy of
Environmental Engineers, Annapolis, MD, 1998.
http://www.epa.gov/cgi-
bin/clprint?Range=Pages& StartPage= 1 &EndPage=3 92&Res=72&Print=Generate+Printa
ble+Document&Title=542B97010+Innovative+Site+Remediation+Technology%3A+Vol
ume+7%2C+Vacuum+Extraction+and+Air+Sparging+&CurrentDoc=img-
link%2FOSWER%2Fimages%2Fepa-
cinb%2F00000853%2F&PageCount=392&Print=Prepare+Document+for+Printing
Bioslurping Publications
1. AFCEE, 1997. Engineering Evaluation and Cost Analysis for Bioslurper Initiative
(A005), Battelle for Air Force Center for Environmental Excellence, Technology
Transfer Division, Brooks Air Force Base, San Antonio, TX, March 25, 1997.
http://www.afcee.brooks.af.mil/er/ert/download/Bioslu01.PDF
2. AFCEE, 1995. Test Plan and Technical Protocol for a Field Treatability Test for POL
Free Product Recovery - Evaluating the Feasibility of Traditional and Bioslurping
Technologies, Air Force Center for Environmental Excellence, Technology Transfer
Division, Brooks Air Force Base, San Antonio, TX, January 1995.
http://www.afcee.brooks.af.mil/er/ert/download/A324068.pdf
3. ESTCP, 2004, Fuel-Specific Bioslurper System Modifications for Enhanced Cost
Effectiveness, CU-9908, Environmental Security Technology Certification Program,
Washington, DC, January 2004.
60
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4. Miller, R., 1996. Bioslurping. TO-96-05, Ground-Water Remediation Technologies
Analysis Center, Pittsburgh, PA, October 1996.
http://www.gwrtac.org
5. NFESC, 1996. Best Practices Manual for Bioslurping, Battelle for Navy Facility
Engineering Service Center, Port Hueneme, CA, June 25, 1996.
http://enviro.nfesc.navy.mil/erb/erb_a/restoration/technologies/remed/comb_mech/Bestpr
ac.pdf
Bioremediation/Natural Attenuation Publications
1. AFCEE, 1999. Natural Attenuation of Fuel Hydrocarbons: Performance and Cost
Results from Multiple Air Force Demonstration Sites, Parsons for Air Force Center for
Environmental Excellence, Technology Transfer Division, Brooks Air Force Base, San
Antonio, TX, October, 1999.
http://www.afcee.brooks.af.mil/er/ert/download/nattattenreport.pdf
2. API, 1997. Field Studies of BTEX and MTBE Intrinsic Bioremediation. American
Petroleum Institute, Publication 4654, Third Edition. Washington, DC.
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
3. API, 1997a. Methods for Measuring Indicators of Intrinsic Bioremediation: Guidance
Manual. American Petroleum Institute, Publication 4658. Washington, DC, November
1997.
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
4. API, 1997b. Effects of Sampling and Analytical Procedures on the Measurement of
Geochemical Indicators of Intrinsic Bioremediation: Laboratory and Field Studies.
American Petroleum Institute, Publication 4657, Washington, DC, November 1997.
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
5. ESTCP, 1999. Cost and Performance Report: Enhanced In Situ Anaerobic
Bioremediation of Fuel-Contaminated Ground Water, Environmental Security
Technology Certification Program, Washington, DC, December 1999.
http://www.estcp.org/documents/techdocs/199522.pdf
6. Hughes, Joseph, 2002. Engineered Bioremediation, Ground Water Remediation
Technologies Analysis Center, Pittsburgh, PA, http://www.gwrtac.org.
7. ITRC, 1998. General Protocol for Demonstration of In Situ Bioremediation
Technologies. The Interstate Technology and Regulatory Cooperation Working Group,
September, 1998.
61
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8. National Academy of Sciences, 2000. Natural Attenuation for Groundwater
Remediation. National Academy Press. Washington, DC, 2000.
http://www.nap.edu/catalog/9792.html
9. NFESC, 1996. Intrinsic Bioremediation of Petroleum Hydrocarbons, Technical
Memorandum TM-2185-ENV, Battelle for Navy Facility Engineering Service Center,
Port Hueneme, CA, June 25, 1996.
http://enviro.nfesc.navy.mil/erb/erb a/restoration/technologies/remed/comb mech/tm-
2185.pdf
10. U.S. EPA, 1999. Use of Monitored Natural Attenuation at Superfund, RCRA
Corrective Action, and Underground Storage Sites, OSWER Directive 9200.4-17P,
Washington, DC.
http://www.epa.gov/swerustl/directiv/d9200417.pdf
11. Van Cauwenberghe, Liesbet, and Diane S. Roote, 1998. In Situ Bioremediation, TO-
98-01, Ground-Water Remediation Technologies Analysis Center, Pittsburgh, PA,
October 1998.
http://www.gwrtac.org.
Groundwater Circulation Wells Publications
1. Miller, Ralinda R., and Diane S. Roote, 1997. In-Well Vapor Stripping, TO-97-01,
Ground-Water Remediation Technologies Analysis Center, Pittsburgh, PA, March 1997.
http://www.gwrtac.org/.
2. Naval Research Laboratory, 1999. "Groundwater Circulating Well Technology
Assessment", NRL/PU/6115- -99-384, Naval Research Laboratory, Washington, DC,
May 1999.
http://www.estcp.org/documents/techdocs/GCWTA.pdf
3. U.S. Department of Energy, 2002. In-Well Vapor Stripping Technology, Innovative
Technology Summary Report, U.S. DOE Office of Science and Technology,
Washington, DC, March 2002 at http://apps. em. doe. gov/ost/pub s/itsrs/itsr6.pdf
4. U.S. EPA, 1998. Field Applications of In Situ Remediation Technologies: Ground-
Water Circulation Wells, U.S. EPA Office of Solid Waste and Emergency Response,
Technology Innovation Office, Washington, DC, October 1998 at http://www.clu-
in.org/embed.cfm?link=%2Fpublications%2Fdb%2Fdb%5Fsearch%2Ecgi%3Fcustom%5
Fsearch%3Dves%26submit%5Fsearch%3Dl
Dual-Phase/Multi-Phase Extraction Publications
1. Charbeneau, RJ. and C.Y. Chiang, 1995. Estimation of Free-Hydrocarbon Recovery
from Dual-Pump Systems, Ground Water, 33(4): 627-634.
62
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2. Peargin, T.R., D.C. Wickland, G.D. Beckett, 1999. Evaluation of Short Term Multi-
phase Extraction Effectiveness for Removal of Non-Aqueous Phase Liquids from
Groundwater Monitoring Wells. Conference Proceedings of the 1999 Petroleum
Hydrocarbons & Organic Chemicals in Ground Water, Houston, TX, NGWA, API, 1999.
3. U.S. Army Corps of Engineers, 1999. Engineering and Design: Multi-Phase
Extraction, Engineer Manual EM 1110-1-4010, U.S. Army Corps of Engineers,
Washington, DC, June 1, 1999.
http://www.usace.army.mil/inet/usace-docs/eng-manuals/em 111 0-1-4010/toc.htm
4. U.S. EPA, 1999. Presumptive Remedy: Supplemental Bulletin, Multi-Phase Extraction
Technology for VOCs in Soil and Groundwater, Directive No. 9355.0-68FS, EPA 540-F-
97-004, U.S. Environmental Protection Agency, Washington, DC, April 1997 at
http://www.clu-in.org/download/toolkit/fmalapr.pdf
Risk Assessment Publications
1. API, 2001. Risk-Based Methodologies for Evaluating Petroleum Hydrocarbon Impacts
at Oil and Natural Gas E&P Sites. American Petroleum Institute, Publication 4709,
Washington, DC, February 2001.
http://api-ep.api.org/filelibrary/4709.pdf
2. Beckett, G.D., P.O. Lundegard, 1997. Practically Impractical - The Limits of LNAPL
Recovery and Relationship to Risk. Conference Proceedings of the 1997 Petroleum
Hydrocarbons & Organic Chemicals in Ground Water. Houston, TX, NGWA, API, 1997.
3. Huntley, D., G.D. Beckett, 1997. Persistence of LNAPL Sources and Relation to Risk.
Conference Proceedings of the 1997 Petroleum Hydrocarbons & Organic Chemicals in
Ground Water. Houston, TX, NGWA and API, 1997.
4. Huntley, D., G.D. Beckett, 1999. Relationship Between Risk Reduction and LNAPL
Recovery. Conference Proceedings of the 1999 Petroleum Hydrocarbons & Organic
Chemicals in Ground Water, Houston, TX, NGWA, API, 1999.
5. U.S. EPA, 1997. Exposure Factors Handbook. Volumes I through III. EPA/600/P-
95/002Fa, Washington, DC.
6. U.S. EPA, 1992. Dermal Exposure Assessment: Principles and Applications, Interim
Report, EPA/600/8-91/01 IB, Washington, DC.
7. U.S. EPA, 1991. Risk Assessment Guidance for Superfund, Volume I: Human Health
Evaluation Manual, Supplemental Guidance. "Standard Default Exposure Factors"
Interim Final, OSWER Directive: 9285.6-03. Washington, DC.
8. U.S. EPA, 1989. Risk Assessment Guidance for Superfund. Volume 1. Human Health
Evaluation Manual, Part A, EPA/540/1-89/002, Washington, DC.
63
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9. U.S. EPA, 1988. Superfund Exposure Assessment Manual, EPA/540/1-88/001,
Washington, DC.
Surfactants/Cosolvents Publications
1. Advanced Applied Technology Demonstration Facility for Environmental Technology
Program (AATDF), 1997. Technology Practices Manual for Surfactants and Cosolvents,
AATDF, Rice University, Houston, TX, February 1997.
http://clu-in.org/PRODUCTS/AATDF/Toc.htm
2. Interstate Technology and Regulatory Cooperation (ITRC), 2003. Technical and
Regulatory Guidance for Surfactant/Cosolvent Flushing of DNAPL Source Zones, ITRC
DNAPL Team, April 2003.
http ://www.itrcweb. org//DNAPL-3 .pdf
3. Lowe, D.F., C.L. Oubre, C.H. Ward, Eds. 1999. Surfactants and Cosolvents forNAPL
Remediation: A Technology Practices Manual, Lewis Publications, Boca Raton, FL,
ISBN: 0-8493-4117-5, 448 pp.
4. Roote, Diane S., 1998. Technology Status Report: In Situ Flushing, TS-98-01, Ground-
Water Remediation Technologies Analysis Center, Pittsburgh, PA, November 1998.
http://www.gwrtac.org
5. Roote, Diane S., 1997. Technology Overview Report: In Situ Flushing, TO-97-02,
Ground-Water Remediation Technologies Analysis Center, Pittsburgh, PA, June 1997.
http://www.gwrtac.org
6. U.S. EPA, 1991. Engineering Bulletin: In Situ Soil Flushing, EPA/540/2-91/021, EPA
Office of Research and Development, Cincinnati, OH, October, 1991.
7. U.S. EPA, 1999. In Situ Enhanced Source Removal, EPA/600/C-99/002, U.S. EPA
and Strategic Environmental Research and Development Program (SERDP), September
1999.
Thermal Technologies Publications
1. Davis, E.L., 1998. Steam Injection for Soil and Aquifer Remediation, Ground Water
Issue, U.S. EPA ORD, OSWER, EPA/540/S-97/505, Washington, DC, January, 1998.
2. Davis, E.L., 1997. How Heat Can Enhance In-situ Soil and Aquifer Remediation:
Important Chemical Properties and Guidance on Choosing the Appropriate Technique,
Ground Water Issue, U.S. EPA ORD, OSWER, EPA/540/S-97/502, Washington, DC,
April, 1997.
64
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3. U.S. EPA, 1999. In Situ Enhanced Source Removal, EPA/600/C-99/002, U.S. EPA
and Strategic Environmental Research and Development Program (SERDP), September
1999.
4. Conceptual Models Publications 1. ASTM, 2003. Standard Guide for Developing Site
Conceptual Models, Publication E1689-95(2003)el. American Society for Testing and
Materials, West Conshohocken, PA.
General and Crosscutting Subject Publications
1. API, 2003. Groundwater Remediation Strategies Tool. American Petroleum Institute,
Publication 4730. Washington, DC, December 2003.
http://api-ec.api.org//filelibrary/4730 Final.pdf.
2. API, 1999. Free-Product Recovery of Petroleum Hydrocarbon Liquids. American
Petroleum Institute, Publication 4682. Washington, DC, June 1999.
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
3. API, 1996. Guidance to the Assessment and Remediation of Underground Petroleum
Releases. American Petroleum Institute, Publication 1628, Third Edition. Washington,
DC. See related publications 1628A-E for Natural Attenuation Processes, Risk-based
Decision Making, Optimization of Hydrocarbon Recovery, In-situ Air Sparging, and
Operation and Maintenance Considerations for Hydrocarbon Recovery Systems,
respectively at http://api-ep.api.org/filelibrary/ACFDA.pdf. Note: These documents must
be ordered from API.
4. API, 1995. Petroleum Contaminated Low Permeability Soil; Hydrocarbon Distribution
Process, Exposure Pathways and In Situ Remediation Technologies. American Petroleum
Institute, Publication 4631. Washington, DC, September 1995.
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
5. Bedient, P.B., H.S. Rifai, CJ. Newell, 1999. Groundwater Contamination, Transport,
and Remediation. Second Edition. Prentice-Hall, Inc. Upper Saddle River, NJ.
6. British Petroleum website for former Amoco refinery, Casper, WY:
http://www.bp.casper.com.
7. Cole, G.M., 1994. Assessment and Remediation of Petroleum Contaminated Sites,
Lewis Publishers, CRC Press, Boca Raton, FL, 360 p.
8. Divine, C. 2001. New Hope forNAPL: A Review of Promising Characterization and
Remediation Techniques, Cont. Soil, Sediment and Water, December, 2001.
65
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9. Huntley, D. and G.D. Beckett, 2002. Persistence of LNAPL Sources: Relationship
Between Risk Reduction and LNAPL Recovery, Journal of Contaminant Hydrology, 59
(2002) 3-26, November 2002.
10. Huntley, D. and G.D. Beckett, 2002. Evaluating Hydrocarbon Removal from Source
Zones and its Effect on Dissolved Plume Longevity and Concentration. American
Petroleum Institute, Publication 4715. Washington, DC, September 2002.
http://api-ec.api.org/filelibrary/4715.pdf
11. Kittel, J.A., A. Leeson, R.E. Hinchee, R.E. Miller, and P. A. Haas. Results of a Multi-
Site Field Treatability Test for Bioslurping: A Comparison of LNAPL Rates Using a
Vacuum-Enhanced Recovery (Bioslurping), Passive Skimming, and Pump Drawdown
Recovery Technique. Available through DTIC.
http://stinet.dtic.mil/cgibin/fulcrum main.pl?database=ft u2&searchid=10518934601329
8&kevfieldvalue=ADA324071&filename=%2Ffulcrum%2Fdata%2FTR fulltext%2Fdoc
%2F AD A3 24071.pdf
12. Lundy, D.A. 2002. There are Better Ways to Regulate Free Product. Groundwater
Monitoring & Remediation. Vol. 22, No. 3. Summer 2002.
13. Mercer, James W. and R. M. Cohen, 1990. A Review of Immiscible Fluids in the
Subsurface: Properties, Models, Characterization and Remediation. Journal of
Contaminant Hydrology, v. 6, p. 107-163.
14. National Academy of Sciences, 1994. Alternatives for Ground Water Cleanup, M.C.
Kavanaugh, J. M. Mercer, etal., National Academy Press. Washington, DC.
http://www.nap.edu/books/0309049946/html/
15. Parsons Engineering Science, Inc., 2000. Source Reduction Effectiveness at Fuel-
Contaminated Sites, Technical Summary Report, Air Force Center for Environmental
Excellence, Technology Transfer Division, Brooks Air Force Base, San Antonio, TX,
February 2000 at http://www.epa.gov/swerustl/pubs/index.htm
16. Sale, T., 2001. Methods for Determining Inputs to Environmental Petroleum
Hydrocarbon Mobility and Recovery Models. American Petroleum Institute, Publication
4711. Washington, DC, July 2001 at http://api-ec.api.org/filelibrary/471 l.pdf.
17. Texas Commission on Environmental Quality (TCEQ), 2003. NAPL Evaluation and
Recovery. TRRP-32 Guidance Document. Draft 8. Austin TX.
http://www.tnrcc.state.tx.us/permitting/remed/techsupp/guidance.htm
18. U.S. EPA, 2003. Institutional Controls: A Guide to Implementing, Monitoring, and
Enforcing Institutional Controls at Superfund, Brownfields, Federal Facility, UST and
RCRA Corrective Action Cleanups, DRAFT Guidance, EPA OSWER, December 2002.
http://www.epa.gov/superfund/action/ic/guide/index.htm
66
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19. U.S. EPA, 2002. Handbook of Groundwater Protection and Cleanup Policies for
RCRA Corrective Action, EPA OSWER 5303W, EPA/530/R-01/015, Washington, DC.
(Note: Internet links updated; policy sections continue to retain the original 2001 date
since no substantial changes made.)
http://www.epa.gov/correctiveaction/resource/guidance/gw/gwhandbk/gwhndbk.htm
20. U.S. EPA, 2000. Institutional Controls: A Site Manager's Guide to Identifying,
Evaluating and Selecting Institutional Controls at Superfund and RCRA Corrective
Action Cleanups, Final Guidance, EPA 540-F-00-005, EPA OSWER 9355.0-74FS-P,
September 2000.
http://www.epa.gov/superfund/action/ic/guide/index.htm
21. U.S. EPA, 1999. "In Situ Enhanced Source Removal", EPA/600/C-99/002, U.S.
Environmental Protection Agency, Washington, DC, September 1999 at
http://hillafb.hgl.com/
22. U.S. EPA, 1996. How to Effectively Recover Free Product at Leaking Underground
Storage Tank Sites: A Guide for State Regulators. EPA 510-R-96-001, EPA OSWER,
NRMRL, Washington, DC, September 1996.
http://www.epa.gov/oust/pubs/fprg.htm
23. U.S. EPA, 1995. How to Evaluate Alternative Cleanup Technologies for
Underground Storage Tank Sites: A Guide for Corrective Action Plan Reviewers.
EPA/510/B094/003 and EPA/510/B095/007 (Original manual covered eight
technologies; two additional chapters added in 1995. QA documents referenced in
document may be outdated), EPA OSWER 5403W, Washington, DC, May 1995.
http://www.epa.gov/oust/pubs/tums.htm
24. U.S. EPA, 1990. Assessing UST Corrective Action Technologies: Early Screening of
Cleanup Technologies for the Saturated Zone, EPA/600/2-90/027, EPA Risk Reduction
Engineering Laboratory.
67
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68
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Appendix E: References
American Petroleum Institute (API): http://www.api.org.
API, 1999. Free-Product Recovery of Petroleum Hydrocarbon Liquids. American
Petroleum Institute Publication 4682. Washington, DC.
API, 1997. Field Studies of BTEX and MTBE Intrinsic Bioremediation. American
Petroleum Institute Publication 4654. Washington, DC.
API, 1997a. Methods for Measuring Indicators of Intrinsic Bioremediation: Guidance
Manual. American Petroleum Institute, Publication 4658, Third Edition. Washington, DC
http://api-ep.api.org/filelibrary/ACFDA.pdf Note: This document must be ordered from
API.
API, 1996a. Compilation of Field Analytical Methods for Assessing Petroleum Product
Releases. American Petroleum Institute, Publication 4635. Washington, DC.
API, 1996b. Guidance to the Assessment and Remediation of Underground Petroleum
Releases. American Petroleum Institute Publication 1628. Third Edition. Washington,
DC.
ASTM website: http://www.astm.org.
ASTM, 2000. Standard Guide for Risk-Based Corrective Action. Publication E2081-00.
American Society for Testing and Materials, West Conshohocken, PA.
ASTM, 2003. Standard Guide for Developing Site Conceptual Models, Publication
E1689-95(2003)el. American Society for Testing and Materials, West Conshohocken,
PA.
ASTM 1995. Standard Guide for Risk-Based Corrective Action Applied at Petroleum
Release Sites, Publication E1739-95. American Society for Testing and Materials, West
Conshohocken, PA.
Bedient, P.B., H.S. Rifai, CJ. Newell, 1999. Groundwater Contamination, Transport, and
Remediation. Second Edition. Prentice-Hall, Inc. Upper Saddle River, NJ.
British Petroleum website for former Amoco refinery, Casper WY:
http://www.bp.casper.com.
British Petroleum, 2003. FPHBaildown Test Procedures: Field Analysis. Global
Environmental Management Company, a BP Affiliated Company. Naperville, IL.
69
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British Petroleum, 2002. Soil and Fluid Sampling and Property Measurements for
LNAPL Saturation and Recovery Estimates. Global Environmental Management
Company, a BP Affiliated Company. Naperville, IL.
Bryan, Todd, 1997. Effective Stakeholder Involvement Strategies for Environmental
Technology Projects: Principles and Practical Applications, Colorado Center for
Environmental Management, Denver, CO.
Charbeneau, R., 2000. Groundwater Hydraulics and Pollutant Transport. Prentice-Hall,
Inc. Upper Saddle River, NJ.
Department of Energy, 1998. DOE Limited Standard. Guidelines for Risk-Based
Prioritization of DOE Activities. DOE-DP-STD-3023-98. Washington, DC.
Federal Facilities Environmental Restoration Dialogue Committee (FFRDC), 1996.
Consensus Principles and Recommendations for Improving Federal Facilities Cleanup.
Gamman, John, Scott McCreary, and Steve Lustgarden, 2001. Finding Solutions for the
Cleanup of the Largest Land-based Oil Spill in the United States: Utilizing a Neutral,
Expert, Fact-Finding Panel in the Guadalupe Oil Field Mediation, Concur Working Paper
01-01.
Groundwater Centralฎ Web Portal: http://www.groundwatercentral.info.
Ground-Water Remediation Technologies Analysis Center (GWRTAC):
http://www.gwrtac.org.
Hughes, Joseph, 2002. Engineered Bioremediation, Ground-Water Remediation
Technologies Analysis Center, Pittsburgh, PA, http://www.gwrtac.org.
Huntley, D., 1997. Analytical Determination of Hydrocarbon Transmissibility from
Baildown Tests. Conference Proceedings of the 1997 Petroleum Hydrocarbons and
Organic Chemicals in Ground Water Conference. Houston, TX, sponsored by the
National Ground Water Association and the American Petroleum Institute.
Huntley, D. and G.D. Beckett, 2002. Evaluating Hydrocarbon Removal from Source
Zones and its Effect on Dissolved Plume Longevity and Concentration. American
Petroleum Institute, Publication 4715. Washington, DC, September 2002.
http://api-ec.api.org/filelibrary/4715.pdf
Lundy, D.A. and L.M. Zimmerman, 1996. Assessing the Recoverability of LNAPL
Plumes for Recovery System Conceptual Design. Proceedings of the 10th NGWA
National Outdoor Action Conference/Exposition, May 1996.
70
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Mercer, James W. and R. M. Cohen, 1990. A Review of Immiscible Fluids in the
Subsurface: Properties, Models, Characterization and Remediation. Journal of
Contaminant Hydrology, v. 6, p. 107-163.
National Academy of Sciences. National Research Council: http://www.nas.edu.
National Academy of Sciences, 2000. Natural Attenuation for Groundwater Remediation.
National Academy Press. Washington, DC, 2000.
http://www.nap.edu/catalog/9792.html.
National Academy of Sciences, 1994. Alternatives for Ground Water Cleanup, M. C.
Kavanaugh, J. M. Mercer, et al., National Academy Press. Washington, DC.
http://www.nap.edu/books/0309049946/html/
Remediation Technologies Development Forum (RTDF) NAPL Cleanup Alliance Web
Site - http://www.rtdf.org/public/napl/
Sale, T., 2001. Methods for Determining Inputs to Environmental Petroleum
Hydrocarbon Mobility and Recovery Models. American Petroleum Institute, Publication
4711. Washington, DC, July 2001 at http://api-ec.api.org/filelibrary/471 l.pdf.
Scrimgeour, Donald, Brad Brockbank, and James Spensley, 1994.
Technology/Regulatory Integration Project Stakeholder Decision-making Model Process
for Technology Demonstrations and Environmental Cleanups, Colorado Center for
Environmental Management, Denver CO.
Texas Commission on Environmental Quality (TCEQ), 2003. NAPL Evaluation and
Recovery. TRRP-32 Guidance Document. Draft 8. Austin TX.
http://www.tnrcc.state.tx.us/permitting/remed/techsupp/guidance.htm
United States Environmental Protection Agency (U.S. EPA) Technology Innovative
Program Websites: http://www.epa.gov/swertio 1/about.htm, http://www.clu-in.org,
http ://www. epareachit.org.
U.S. Environmental Protection Agency (EPA), 2003. Institutional Controls: A Guide to
Implementing, Monitoring, and Enforcing Institutional Controls at Superfund,
Brownfields, Federal Facility, UST and RCRA Corrective Action Cleanups, DRAFT
Guidance, EPA OSWER, December 2002.
http://www.epa.gov/superfund/action/ic/guide/index.htm
U.S. EPA, 2002. Handbook of Groundwater Protection and Cleanup Policies for RCRA
Corrective Action, EPA OSWER 5303W, EPA/530/R-01/015, Washington, DC. (Note:
Internet links updated; policy sections continue to retain the original 2001 date since no
substantial changes made.)
http://www.epa.gov/correctiveaction/resource/guidance/gw/gwhandbk/gwhndbk.htm
71
-------
U.S. EPA, 2000. Institutional Controls: A Site Manager's Guide to Identifying,
Evaluating and Selecting Institutional Controls at Superfund and RCRA Corrective
Action Cleanups, Final Guidance, EPA 540-F-00-005, EPA OSWER 9355.0-74FS-P,
September 2000.
http://www.epa.gov/superfund/action/ic/guide/index.htm
U.S. EPA, 1999. Use of Monitored Natural Attenuation at Superfund, RCRA Corrective
Action, and Underground Storage Sites, OSWER Directive 9200.4-17P, Washington,
DC.
http://www.epa.gov/swerustl/directiv/d9200417.pdf
U.S. EPA, 1997a. Rules of Thumb for Superfund Remedy Selection. EPA 540-R-97-013.
http://www.epa.gov/superfund/resources/rules/rulesthm.pdf
U.S. EPA, 1997b. Exposure Factors Handbook. Volumes I through III. EPA/600/P-
95/002Fa, Washington, DC.
U.S. EPA, 1996. How to Effectively Recover Free Product at Leaking Underground
Storage Tank Sites: A Guide for State Regulators. EPA 510-R-96-001, EPA OSWER,
NRMRL, Washington, DC, September 1996.
http://www.epa.gov/oust/pubs/fprg.htm
U.S. EPA, 1995. How to Evaluate Alternative Cleanup Technologies for Underground
Storage Tank Sites: A Guide for Corrective Action Plan Reviewers. EPA/510/B094/003
and EPA/510/B095/007 (Original manual covered eight technologies; two additional
chapters added in 1995. QA documents referenced in document may be outdated), EPA
OSWER 5403W, Washington, DC, May 1995.
http://www.epa.gov/oust/pubs/tums.htm
U.S. EPA, 1995. Underground Storage Tank Sites: A Guide for Corrective Action Plan
Reviewers, EPA510/B-95/007.
U.S. EPA, 1992. Dermal Exposure Assessment: Principles and Applications, Interim
Report, EPA/600/8-91/01 IB, Washington, DC.
U.S. EPA, 1991. Risk Assessment Guidance for Superfund, Volume I: Human Health
Evaluation Manual, Supplemental Guidance. "Standard Default Exposure Factors"
Interim Final, OSWER Directive: 9285.6-03. Washington, DC.
U.S. EPA, 1989. Risk Assessment Guidance for Superfund. Volume 1. Human Health
Evaluation Manual, Part A, EPA/540/1-89/002, Washington, DC.
U.S. EPA, 1988. Superfund Exposure Assessment Manual, EPA/540/1-88/001,
Washington, DC.
72
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