xvEPA
United States
Environmental Protection
Agency
Office of
Research and Development
Washington, DC 20460
Research and Development
EPA/600/8-86/004 April 1986
EPA Ground-Water
Research Programs
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EPA/600/8-86/004 April 1986
EPA Ground-Water Research Programs
Program Report—Office of Research
and Development
Office of Acid Deposition, Environmental Monitoring,
and Quality Assurance
Washington, DC 20460
Office of Environmental Engineering and Technology
Washington, DC 20460
Office of Environmental Processes and Effects Research
Washington, DC 20460
Office of Exploratory Research
Washington, DC 20460
Environmental Monitoring Systems Laboratory
Las Vegas, NV 89114
Environmental Research Laboratory
Athens, GA 30613
Hazardous Waste Engineering Research Laboratory
Cincinnati, OH 45268
Robert S. Kerr Environmental Research Laboratory
Ada, OK 74820
This document was published by:
U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460
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This report was prepared for the Office of Research and
Development under the guidance of Stephen Cordle, Office of
Environmental Processes and Effects Research. All material
was written by Brana Lobel of Eastern Research Group, Inc.,
Arlington, Massachusetts, from material provided by the Office
of Research and Development.
This report has been reviewed and approved for publication.
Mention of trade names or commercial products does not con-
stitute endorsement or recommendation for use.
Comments or questions regarding this report should be
addressed to:
Stephen Cordle
Office of Environmental Processes and Effects Research
(RD-682)
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, DC 20460
(202) 382-5940
Acknowledgment is made to the many persons who were
involved in reviewing draft material and especially to those who
provided technical assistance. Major contributors were:
Environmental Monitoring Systems Laboratory—LV
Lawrence Eccles and Robert Snelling
Environmental Research Laboratory—ATH
Robert Ryans
Hazardous Waste Engineering Research Laboratory—CIN
Ronald Hill, Robert Landreth, Hugh Masters, Norbert
Schomaker, and Richard Traver
Robert S. Kerr Environmental Research Laboratory—ADA
James McNabb
Office of Environmental Engineering and Technology—DC
Marshall Dick
Special thanks to: Fred Milanovich, Lawrence Livermore
National Laboratory; Paul Roberts, Stanford University; and
Gary Sayler, University of Tennessee.
Photographs courtesy of David Balkwill, Robert Landreth, Hugh
Masters, James McNabb, Fred Milanovich, Richard Nash,
Robert Ryans, Gary Sayler, Kristin Stout, and the U.S. Geo-
logical Survey.
For further information about laboratory ground-water programs
or projects, contact:
Environmental Monitoring Systems Laboratory, Las Vegas, NV
Erich Bretthauer, Director (702) 798-2100
Environmental Research Laboratory, Athens, GA
Rosemarie C. Russo, Director (404) 546-3134
Hazardous Waste Engineering Research Laboratory, Cincinnati, OH
Thomas R. Hauser, Director (513) 569-7418
Robert S. Kerr Environmental Research Laboratory, Ada, OK
Clinton W. Hall, Director (405) 332-8800
Single copies of this report are available from:
Office of Research and Development
Distribution Unit
U.S. Environmental Protection Agency
Cincinnati, OH 45268
Cover: Ground water moves slowly under the earth, filling fractures and
fissures as well as saturating microscopic pores in rock and soil. If
ground water could be seen, a vertical cross-section of a portion of an
aquifer might look like this.
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Contents
1. Introduction 1
Ground Water: An Overview 1
EPA and ORD: Ground-Water Roles 3
ORD: Current Research 5
2. Source Control 7
The Hazardous Waste Land Disposal Program 9
The Removal and Remedial Action Program 12
3. Prediction 15
Hydrogeologic Processes 17
Physical and Chemical Processes 20
Biological Processes 21
4. Monitoring 22
Monitoring and Sampling 25
Geophysical Monitoring Techniques 26
Interpretive Analysis 27
5. In Situ Aquifer Cleanup 28
Case Histories and Cost-Benefit Analyses 28
Technology 28
6. Information Transfer and Technical Assistance 31
Activities 31
Centers 32
7. Synergism in Research: The Stanford/Waterloo Project 33
Study of Organic Contaminant Transport 33
Landfill Leachate Studies 34
8. Future Directions 35
Appendix A: Ground-Water Research Review Committee,
Principal Findings and Recommendations from the Report
on the Review of the Environmental Protection Agency's
Ground-Water Research Program, Submitted by the
Ground-Water Research Review Committee, Science
Advisory Board, U.S. EPA, July 1985. 36
Appendix B: Ground-Water Research in Other
Federal Agencies 39
in
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1. Introduction
Water, water every where.
Nor any drop to drink.
Samuel Taylor Coleridge
The Rime of the Ancient Mariner
As recently as 10 years ago, ground water was generally
considered a pristine resource: pure and ever-available.
Like many of the gifts of the subsurface, it was used, and
sometimes abused, without being fully understood. The
late 1970s brought a rude awakening for the public; syn-
thetic organic chemicals were discovered in ground-
water-supplied drinking water sources in several states,
including California, Connecticut, Massachusetts, Michi-
gan, New York, and New Jersey. This was only the begin-
ning. Years of improper disposal and unregulated
dumping practices resulted in the release of a Pandora's
box of toxic contaminants. Currently, 40 states have
documented instances of serious ground-water contami-
nation (1). These problems have become a matter of
national concern. As surveys and investigations proceed,
more instances will undoubtedly be uncovered. Because
ground water is both vital and vulnerable, its contamina-
tion promises to be a major environmental issue of the
'80s and '90s.
This document describes the U.S. Environmental Protec-
tion Agency's (EPA's) ground-water research programs.
The programs focus on protection of ground-water
resources by eliminating or controlling sources of con-
tamination; understanding and predicting the movement
and attenuation of contaminants in the subsurface;
monitoring for contamination; restoring polluted aquifers;
and ensuring that research findings are conveyed to pub-
lic officials, field managers, and the scientific community.
This document describes these activities, highlights
recent research accomplishments, and outlines priorities
for future investigation. Readers who desire more
detailed technical information about the programs or
individual projects may contact the research laboratories
directly (see page i).
Ground Water: An Overview
Ground water is a vast and important resource. In the
United States, approximately 15 quadrillion gallons
(56 quadrillion liters) of water are stored within 0.5 miles
(0.8 kilometers) of the land surface (1). Ground water
supplies about 25 percent of all fresh water used (2).
Fifty per cent of U.S. citizens obtain all or part of their
drinking water from ground water; 95 per cent of rural
households depend totally upon it (1). Commercially,
ground water is extensively employed in agricultural prac-
tices, particularly for irrigation, and in various industries
Rural Households
and Livestock
(6%)
Agriculture: Irrigation
and Other Purposes
(67%)
Self-Supplied
Industrial Water
(13%)
Figure 1. Major Uses of Ground Water in the United States.
(Figure 1). Currently, ground-water withdrawals total
about 90 billion gallons (340 billion liters) a day, a three-
fold increase in usage since 1950 (Figure 2) (1).
Ground water (subsurface water located below the water
table) is stored in various rock or soil bodies. While
potentially replenishable, it can easily be contaminated.
Once polluted, ground water is difficult, sometimes
impossible, and always expensive to clean up using cur-
rently available methods.
In general, contaminants that are soluble follow the natu-
ral path of ground water as it moves in the subsurface
portion of the hydrologic cycle (Figure 3). However,
insoluble contaminants may move in different directions
from ground-water flow (see Section 3, Prediction for a
discussion of these phenomena). Contamination begins
with the source. Ground water may be contaminated by
routes such as waste disposal or nondisposal use of
chemicals on the land surface. Of these, waste disposal
sources present the most serious problem, according to
current reports from several states (1). These sources
include industrial and municipal landfills and lagoons,
underground storage tanks, and chemical spills. Other
sources of contamination include well injections, pesti-
cides, fertilizers, septic tanks, and, to a lesser extent, salt
or brackish water intrusion, road salts, feedlot wastes,
wastewater treatment, land use practices, and mining
activities. Among the most troublesome contaminants
are organic solvents, gasoline, heavy metals, inorganic
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INTRODUCTION
90
1 80
70
60
50
40
30
20
10
Total ground -water withdrawals
>>„
• Public supply
•Rural supply
1950 1955 1960 1965 1970 1975 1980
Figure 2. Trends in Ground-Water Withdrawals in the United
States, 1950-1980.
chemicals, organic chemicals, pesticides, pathogens, and
nitrates.
Contaminants may leak, percolate, or be injected into
aquifers. As contaminants travel through the soil, and
into and through a ground-water system, they may be
slowed down or degraded by processes which are com-
plex and not completely understood. These natural
processes are not totally effective for all contaminants.
For example, soils were once believed to be capable of
binding and holding all chemicals. This is now known not
to be true for some important and widely used classes of
chemicals, for example, organic solvents such as tri- and
tetrachloroethylene, benzenes, and carbon tetrachloride.
Other contaminants, such as heavy metals, are not
degradable at all, but may be immobilized. Depending on
the nature of the discharge and the type of pollutant,
contaminants may enter ground water as slugs (isolated
masses) or localized plumes.
In general, ground water moves slowly (only a few feet
to several hundred feet a year), but because it continues
to move, the contaminants it bears eventually discharge
to the surface in most cases. Points of discharge can
include wells or springs, or surface water bodies such as
rivers and lakes. Since the base flow of most streams is
supported by ground-water discharge, the usefulness of
both surface and ground water may be severely com-
promised when the quality of ground water is degraded.
Rainfall, completing the hydrologic cycle, replenishes
ground water, but it may add to the contamination if it
moves through overlying soil that contains pollutants.
Although ground-water supplies are generally abundant
in the United States, they vary by region in quality, quan-
tity, and accessibility. The contamination of aquifers
(geologic formations capable of yielding a significant
amount of ground water to wells or springs) is becoming
a problem for an increasing number of regions and locali-
ties. Public officials, industry managers, and private
citizens may be confronted with the issue when contami-
nation is discovered in a heavily populated area or valua-
ble ecosystem.
Not only place, but time enters the equation as well; the
long-term nature of ground-water contamination is unar-
guable. Some contemporary American examples can be
traced to disposal activities conducted 30 or 40 years
before, but an instance in England, for example, has been
traced to pollutant dumping done 135 years previously. In
fact, some landfills from the Roman Empire still produce
leachate. This huge potential time-span for contamina-
tion makes the task of ground-water research particularly
complex; not only must current and future concerns,
such as protection and prevention, be addressed, but
methods of dealing with prior contamination must also
be explored.
Current knowledge of the extent and severity of ground-
water contamination is limited, and it is likely that the
coming years will reveal additional contamination as
investigative techniques become increasingly sophisti-
cated and accurate, and more comprehensive data are
collected. In developing strategies to deal with the prob-
lem, environmental consequences must be balanced
against feasibility and costs. The United States, with its
plethora of different climates, hydrogeologies, population
densities, types and levels of industries, and other varia-
bles, requires a number of different strategies and priori-
ties at the state and local level. Solutions may be as
diverse as problems. Areas where aquifers lie close to the
surface, or in rapid recharge locations, may face a differ-
ent set of contamination issues from regions where
ground water lies deeply buried. In some situations,
aquifer cleanup—no matter how expensive—may be the
only viable alternative; in others, alternative solutions can
be found. Any effective strategy, however, must be sup-
ported by a coherent base of scientific knowledge and
sound management.
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INTRODUCTION
LEGEND
Contaminant Path
Ground-Water Path
Figure 3. Contaminants in Ground Water: Their Relationship to the Hydrologic Cycle.
EPA and ORD: Ground-Water Roles
EPA derives its statutory authority to protect ground
water from the Clean Water Act (CWA), the Comprehen-
sive Environmental Response, Compensation, and Liabil-
ity Act (CERCLA or Superfund), the Safe Drinking Water
Act (SDWA), the Resource Conservation and Recovery
Act (RCRA), the Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA), and the Toxic Substances Con-
trol Act (TSCA). In addition to these statutory mandates,
in August 1984, through the Office of Ground-Water Pro-
tection, EPA established a Ground-Water Protection
Strategy, featuring four components:
• Short-term build-up of institutions at the state level.
• Assessing the problems that may exist from unad-
dressed sources of contamination—in particular,
leaking storage tanks, surface impoundments, and
landfills.
• Issuing guidelines for EPA decisions affecting
ground-water protection and cleanup.
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INTRODUCTION
• Strengthening EPA's organization for ground-water
management at the headquarters and regional
levels, and strengthening EPA's cooperation with
Federal and state agencies.
While it is important to develop and implement national
ground-water policies, protection programs must be area-
specific on the operational level because of the complex-
ities of individual situations. For this reason, state and
local governments are assuming primary responsibility in
assessing and controlling their ground-water problems,
and are working in partnership with EPA, which provides
national drinking water standards, general program goals,
research, information, and technical assistance.
A protection program may focus on a small aquifer that
is the sole source of drinking water for a locality, or may
be a large, regional project dealing with an aquifer that
underlies several states. The EPA and state and local
governments require extensive information to develop,
implement, and evaluate ground-water protection pro-
grams. For each program, managers must be able to:
• Determine the number and types of contamination
sources.
• Assess the extent and nature of existing and poten-
tial contamination.
• Predict and/or measure concentrations of con-
taminants in water supplies.
• Ascertain the health implications of these concen-
trations.
• Compare alternative prevention and/or cleanup
measures and assess their costs.
• Evaluate program effectiveness.
To assist in accomplishing these goals, the EPA's Office
of Research and Development (ORD) conducts several
research efforts. SDWA and RCRA provide the major
funding sources for ground-water research. Funding for
the programs, in fiscal year (FY)'85 totals $18.1 million
(Figure 4); funding is expected to rise to $22.4 million in
FY'86. This reflects a growing awareness of the impor-
tance of investigating ground-water problems; in particu-
lar, the control of hazardous wastes and leaking
underground storage tanks. The EPA's ground-water
research programs, aimed at protecting the resource,
have five major goals:
• To develop and improve methods to control sources
of contamination.
• To improve methods for predicting and assessing
contaminant transport and fate.
• To develop ground-water monitoring technology.
Total Funding in
$18.1M
Source Control
Prediction
Monitoring
In Situ Aquifer
Cleanup
1985
9.2 M
6.3 M
1.7 M
0.85M
Figure 4. FY'85 Funding Allocations for EPA Ground-Water
Research Programs.
• To devise means for aquifer cleanup.
• To provide technical assistance and information
transfer for all these subjects.
ORD administers fourteen laboratories throughout the
United States, four of which conduct research directly
related to protecting ground water (Figure 5). Other ORD
labs study drinking water quality, health effects, treat-
ment technologies, analytical methods for water sam-
ples, and techniques for quality assurance. These
investigations, which often address contaminants occur-
ring in both surface and ground water, also provide val-
uable informational and control tools.
Because of its complexities, the study of ground water
requires cooperative efforts by scientists and technical
specialists from many disciplines. Agronomists, biolo-
gists, biochemists, chemists, engineers, environmental
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INTRODUCTION
ADEMQA/HQ = Office of Acid Deposition, Environmental Monitoring, and
Quality Assurance
EMSL/LV = Environmental Monitoring Systems Laboratory in Las Vegas
ERL/ATH = Environmental Research Laboratory in Athens
HWERL/CIN - Hazardous Waste Engineering Research Laboratory in Cincinnati
OEET/HQ = Office of Environmental Engineering Technology in Washington
OEPER/HQ = Office of Environmental Processes and Effects Research in Washington
OER/HQ = Office of Exploratory Research in Washington
RSKERL/ADA = Robert S.Kerr Environmental Research Laboratory in Ada
RSKERL/ADA • Ma' oklah°™
Figure 5. EPA Offices and Laboratories Involved in Ground-Water Research Programs. All offices and laboratories shown
here are part of the Office of Research and Development.
scientists, geologists, hydrologists, mathematicians,
microbiologists, soil scientists, and physicists all con-
tribute their expertise to various facets of ground-water
research. ORD funds or maintains contact with various
organizations and members of the scientific community,
including universities, information centers, institutes,
consultants, and engineering firms. Several other Federal
agencies also conduct research on ground water (see
Appendix A for further information).
ORD provides research products, information, and
assistance to a wide range of clients, including EPA pro-
gram and regional offices, other Federal agencies, state
and local governments, industry representatives, environ-
mental groups, professional associations, foundations,
institutes, consultants, and researchers.
A series of mechanisms have been established to ensure
that EPA's ground-water research programs continue to
meet client needs. ORD has formed the Ground-Water
Research Planning Group to advise on overall issues in
the areas of prediction, monitoring, and cleanup. This
group includes members of all relevant EPA program
offices plus several EPA regional representatives. The
Planning Group reports to both the Water Research Com-
mittee and the Hazardous Waste/Superfund Committee,
which advise the Assistant Administrator for Research
and Development on research priorities (Figure 6). At the
state level, ORD has developed a cooperative agreement
with the National Governors' Association to provide a
mechanism for interaction on the research needs of
specific states.
ORD: Current Research
Research on the quality of ground water is essentially a
new discipline: complex, full of unknowns, and still in the
process of being mapped out. In recent years, scientific
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INTRODUCTION
Hazardous Waste/
Superfund
Research Committee
Ground-Water Research
Planning Group
Office of Research and Development
Office of Drinking Water
Office of Solid Waste
Office of Emergency and
Remedial Response
Office of Waste Programs
Enforcement
Office of Pesticide Programs
Office of Toxic Substances
Office of Policy, Planning,
and Evaluation
Regions I, IV, VI, and X
Office of Ground-Water Protection
Figure 6. EPA Ground-Water Research Planning Mechanism.
knowledge about ground-water systems has been
increasing rapidly. The ability to take uncontaminated
samples in the subsurface—previously a major limitation
in research—has been greatly improved. At ORD,
researchers have developed techniques that allow them
to enumerate and characterize subsurface microbes.
ORD scientists have also stimulated the aerobic bio-
degradation of trichloroethylene (TCE) (see Section 5, In
Situ Aquifer Cleanup). Improvements have been made in
technology for assessing the subsurface. Advances have
been made in adapting techniques from other disciplines
to successfully identify specific contaminants in ground
water (see Section 4, Monitoring). The behavior of cer-
tain chemicals in some geologic materials can be
assessed.
Much remains to be learned, however. The technologies
for source control need to be reviewed, assessed, and
Cape Cod, Massachusetts. Contaminated ground water, foam-
ing with non-biodegradable detergents, is pumped from a
monitoring well into this bucket 30 years after the original
contamination had occurred.
refined. Basic research is needed to develop models for
prediction of contaminant movement and transformation
in complex aquifer systems. Monitoring technology,
despite specific advances, in general remains cumber-
some, costly, and imprecise. Little information is available
on the costs or effectiveness of current methods for
cleanup of aquifers in situ. Before ground water can be
said to be truly protected as an environmental resource,
further research is necessary. The most effective means
of protection is prevention —in this case, controlling the
sources of contamination.
References
1. Babbit, B., Governor. 1984. From the states' point of
view. EPA Journal 10(6):11.
2. U.S. EPA. 1984. Facts about ground water. EPA Jour-
nal 10(6):7.
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2. Source Control
Control of contaminant sources on the land surface
represents both the beginning and end point of current
ground-water research efforts. Until more is known about
subsurface processes and their interaction with specific
contaminants, source control remains the primary
method for preventing ground-water contamination. At
the same time, source control techniques are also used
where contamination has already occurred, for example,
in the cleanup of unregulated dump sites or in emergency
response to accidental spills.
A major source of ground-water pollution is the improper
disposal of hazardous wastes. Contamination may occur
from sources such as landfills, surface impoundments, or
injection wells. Research must address all aspects of the
technology associated with preventing contamination:
improving the design, construction, operation, and main-
tenance of disposal systems; increasing knowledge
about leachates; and improving techniques for emer-
gency and ongoing handling and destruction of wastes at
uncontrolled sites.
ORD supports two source control research programs
through the Hazardous Waste Engineering Research
Laboratory in Cincinnati, Ohio (HWERL-CIN) (Figure 7).
Both programs develop and evaluate state-of-the-art
technology for hazardous waste management, storage,
and disposal. The Hazardous Waste Land Disposal Pro-
gram, in support of RCRA disposal regulations and guide-
lines, investigates landfills, surface impoundments, and
Hazardous Waste 1
Land Disposal Program 1
1
SOURCE CONTROL
Hazardous Waste
Engineering Research
Laboratory
Cincinnati, Ohio
\&$M88$&
Component Development System Design and
and Assessment Construction
IV:::::::::::::::::::::::::::::::: XXttXXXVf \^ffffffffff^MKf^ffy
?SSSiwSSS;:/
1 Removal and Remedial
1 Action Program
\88$!$$88 S^^^^r
Removal Action Remedial Action
v&Si&SS^ \^^^f^^^f^^
1
• Covers • Landfills and
• Liners Surface Impoundments
• Waste Leaching • Underground
• Waste Modification Storage
mmmmmmm L
• Assessment
- Spills
- Uncontrol
• Contammen
• Hazardous Wastes
_ • Contaminated Soils
ed Waste Sites
t/ ireatment N^S^SSv^vSSft'-'-vvv^v/
- Uncontrolled Waste Sites
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Figure 7. Highlights of EPA Ground-Water Source Control Research.
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SOURCE CONTROL
underground storage facilities. The Removal and
Remedial Action Program develops technology for emer-
gency and ongoing hazardous waste site cleanup in sup-
port of CERCLA (Superfund). Table 1 lists current source
control projects for both programs.
Table 1. Source Control Research
Hazardous Waste Engineering Research Laboratory —Cincinnati, OH
AREA OF CONCERN
PROJECT TITLE
PURPOSE
GOALS AND PRODUCTS
Land Disposal
Office of Environmental
Engineering and
Technology (OEET) -
Hazardous Waste —
Surface Impoundments
Assess and develop improved design, operation, and
closure components for landfills, surface impound-
ments, and waste piles used for hazardous waste man-
agement. Areas covered include gas and VOC (volatile
organic chemical) emission control technologies, clay
soil and FML (flexible membrane liner) liner perform-
ance, cover performance, contaminant/soil interaction,
leachates, leak detection techniques, and dike con-
struction criteria.
Technical Resource Documents
(TRDs).
Computer programs to review land
disposal permit applications.
"Expert Information" computer-
ized systems on containment
technologies.
Technical assistance to RCRA
permit writers.
Improved design and technology.
Land Disposal
OEET-Hazardous Waste
Technical Resource
Documents
Develop and update technical manuals for landfilling
and surface impoundment of hazardous wastes, includ-
ing information such as design, construction, and oper-
ating and monitoring procedures. The manuals will
address the design and installation of liners, the design
of landfill covers to prevent infiltration, and closure
procedures for surface impoundments.
Provide state-of-the-art technical
information to field managers and
Federal, state, and local officials.
1 Develop and improve the perform-
ance of components and the unit
operations of secure landfills to
comply with RCRA regulations.
Land Disposal
Support to Land Disposal
Develop design, operation, maintenance, and closure
procedures for landfills. Research topics include the
effects of subsidence on cover performance, chemical
compatibility and service life prediction for synthetic
liners, leachate collection and treatment efficiency,
cost effectiveness of multi-layer cover systems,
assessment of maintenance-free cover systems, and
the impact of designing secure landfills in saturated
soils.
Remedial Action
Chemical Treatment
Methods for Dioxins and
Dibenzofurans
Develop and evaluate methods for the destruction of
dioxins and other chemically related wastes in soils,
sediments, and contained waste streams. Laboratory
and field studies will address the feasibility of UV pho-
tolysis and APFEG reagents for treatment of dioxin-
contaminated soils, the removal of chlorinated dioxins
from contaminated soils, the application of alkali poly-
ethylene glycolate complexes to destroy dioxins in
Missouri soils, and the supercritical extraction of
chlorinated dioxins from soils.
• Improve chemical and physical
contaminant destruction
technology.
Remedial Action
Dioxin Assessment and
Control Research
Evaluate the feasibility of incineration for on site detox-
ification of dioxin-contaminated liquid wastes and
soils.
Improve contamination destruc-
tion processes.
Remedial Action
Engineering Support for
Site and Situation
Assessment
Apply engineering expertise to assessments of hazard-
ous waste site situations (e.g., waste characteristics,
hydrology, geology, and soil characteristics) to assist in
developing corrective measures. Develop criteria for
conducting site assessments. Prepare feasibility
studies regarding data requirements for remedial action
decisions.
• Technical assistance at hazardous
waste sites.
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SOURCE CONTROL
Table 1 Cont.
AREA OF CONCERN
PROJECT TITLE
PURPOSE
GOALS AND PRODUCTS
Remedial Action
Provide Technical Support
to Enforcement Program
and Regional Offices
Provide scientific information and analyses in support
of litigation on corrective actions at Superfund sites.
Support areas include review of designs for remedial
actions, review of data submitted by liable parties,
expert witness testimony, technology transfer, emer-
gency response assistance at releases and waste sites,
supervision of cleanup operations involving ORD equip-
ment, analytical support using mobile and central
laboratories, and technical support regarding the desig-
nation of hazardous substances and assignment of
reportable quantities.
Technical assistance to EPA
regional and state and local
officials.
Removal and
Remedial Action
Evaluate Technology to
Manage Uncontrolled
Waste Sites
Evaluate improved and new technologies for emer-
gency and remedial actions for hazardous material
spills and newly discovered releases of hazardous sub-
stances from uncontrolled waste sites. Topics include
field evaluation of prototypical mobile equipment and
innovative commercially available equipment, the use
of chemicals for mitigation of the effects of hazardous
substance releases, fugitive dust control procedures,
and the fixation of contaminated soils.
Provide most effective technology
for spill control and release
cleanup.
Removal Action
Prevent and Contain Haz-
ardous Material Releases
Develop new and improved technology for the preven-
tion and control of pollution from hazardous material
releases by adapting related industrial technologies.
Research topics include spill or accidental release
prevention, pre-response planning, containment and
confinement, separation and concentration, the
destruction of collected cleanup residuals, and the
selection of chemicals to control releases of floating
hazardous substances.
Improve technology for emergency
handling of hazardous releases.
Removal Action
Special Biodegradation
Processes for Detoxifying
Contaminated Soils
Develop and evaluate biological methods for the
destruction or detoxification of chemicals in soils.
Genetic engineering and other biological techniques
will be used to determine if living organisms such as
plants, yeast, and microbes can be employed to suc-
cessfully transform or degrade such substances as
organochlorme compounds, 2,4,5-trichlorophenoxy-
acetic acid, chlorinated dioxins, and halogenated
hydrocarbons.
Cost-effective decontamination
techniques.
The Hazardous Waste Land Disposal Program
Land disposal—the temporary or permanent storage of
wastes on or under the land surface —is currently the pri-
mary means of hazardous waste containment. Emerging
techniques for contaminant destruction and land banning
of some wastes suggest a future where land disposal will
lose its primacy. However, some wastes will still be land
disposed, for example, because of large volume or lack of
alternate disposal options. In addition, residues from
other disposal methods such as incineration will be land
disposed. For these reasons, refinements in land disposal
technology will be necessary.
The Hazardous Waste Land Disposal Research Program
develops, tests, and assesses the technology of land dis-
posal systems in order to ensure the safe disposal and
storage of hazardous wastes. Information from investiga-
tions on specific subjects, such as liner selection, system
design, and waste modification techniques is compiled
into technical resource documents (TRDs) which are
used for review and evaluation of land disposal permit
applications mandated by the Resource Conservation and
Recovery Act (RCRA). To produce TRDs, the program
engages in bench and pilot studies, economic assess-
ments, laboratory analyses, and full-scale field verifi-
cation studies.
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SOURCE CONTROL
Currently, HWERL researchers and contractors:
• Evaluate the design and construction of land dis-
posal systems.
• Develop and assess system components, including
cover systems, liners, waste leaching, and waste
modification.
• Provide information on these subjects to the user
audience through written material, conferences, and
computerized systems.
To date, the program has emphasized landfills; although
surface impoundments have similarities in design and
construction, their unique features require more research
attention in the future. The potential use of a third con-
tainment option —underground storage —is being
explored.
Cover Systems
HWERL engineers are developing, evaluating, and com-
paring various landfill cover systems for long-term dura-
bility and for relative efficiency at preventing infiltration.
Cover materials such as flexible membranes (plastic
or rubber sheeting) and waste residue (for example,
fly ash and papermill sludge) are being evaluated as
alternatives to or combinations with soils and
grasses, which are currently the most commonly
used cover materials.
Cover designs consist of several materials in alter-
nating layers (Figure 8). One design being field-
tested is a three-layered cover system. Researchers
are measuring surface runoff, subsurface drainage,
leachate formation, and soil moisture distribution
under natural and artificial rainfall conditions.
Land subsidence over time may impair the effective-
ness of a cover system. Studies are currently evalu-
ating the impact of land subsidence on flexible
membrane covers and on three-layered cover sys-
tems. Another research tool is the Hydrological
Evaluation of Landfill Performance (HELP) model, a
representation of subsurface drainage that has been
computerized as an aid to evaluating the effect of
subsidence on cover performance.
Gas Vent
(if required)
NOTE:
Geotextiles
may be used
above & below
flexible
membrane
liner
to prevent
membrane
puncture.
Shallow-Rooted
Self-Sustaining
Vegetation
Soil Layer
Drainage Layer
Flexible Membrane Liner
Clay Barrier
Figure 8. Prototype Four-Layer Cover Design. (Idealized; not drawn to scale.)
10
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SOURCE CONTROL
This research will be integrated into a technical resource
document (TRD) which presents information on methods
to improve cover design, and on construction, main-
tenance, and inspection techniques for clay and flexible
membrane cap performance, cap drainage, and
maintenance-free vegetation cover systems.
Liners
When choosing the most appropriate liner material for a
disposal facility, the designer must consider the advan-
tages and disadvantages of the material based on the
nature of the waste, the characteristics of the site, and
relative costs. For example, clay soil materials may be
less expensive but are more permeable than flexible
membrane liners (FMLs); however, FMLs may be
damaged by poor installation procedures, or over time by
tears, leaks, rodents, or chemical action.
• Clay soil liners are being examined for their response
to organic and inorganic leachate components.
Researchers are assessing the effects of organic
solvents on clay soil permeability, developing a
matrix to predict soil/waste interaction, and evaluat-
ing the adverse impact of soil shrinkage on perfor-
mance when selected inorganic salt solutions are
placed in contact with the liner. Laboratory soil
porosity tests are being evaluated for use as perfor-
mance indicators to predict the retention and rate of
movement of pollutants through soil liners. Liners
are also being evaluated to determine causes for
failures. TRDs are being developed 1) to evaluate
clay soils as liners and 2) to describe proper con-
struction, maintenance, and inspection procedures
for installation.
• Synthetic liners are being tested to determine their
long-term life and resistance to chemical (leachate)
attack. Methods to assist the designer on FML
selection are being developed. Field studies are con-
centrating on evaluating installation techniques as
well as methods for locating and repairing leaks in
liners (for example, patching and grouting), and for
detecting leaks by means of electrical resistance.
Increasing awareness about and use of flexible
membrane liners have generated a substantial
amount of new information. The latest research
findings are being incorporated into a TRD.
Waste Leaching
Methods for predicting leachate composition and flow
time, and possible methods for treatment are being inves-
tigated at HWERL labs and field sites.
A III
Workers installing a flexible membrane liner in a landfill. Proper
installation techniques are important to minimize tears and
seam leaks. HWERL is revising its technical resource document
(TRDI on liner systems to include minimum technological stan-
dards for double liners required by 1984 RCRA amendments.
• The predictive effectiveness of techniques of
leachate extraction (for example, batch extraction
and column leaching) is being compared using haz-
ardous waste samples with diverse physical and
chemical characteristics.
• Models are being developed to evaluate predictive
methods for determining liquid flow rates through
landfilled wastes. Another model is being developed
to predict saturation levels in landfills to assess how
effectively a system can control the production of
leachate over time. A predictive model for pollutant
rate of release is being evaluated through compari-
son with actual pollutant activity at a field site.
• Laboratory studies have been initiated to develop
and evaluate physical, chemical, and biological
treatments for hazardous waste disposal sites.
These investigations may eventually lead to the use
of landfills as in situ reactors to minimize or neu-
tralize toxic waste components.
Waste Modification
As an additional deterrent to leachate formation, waste
may be rendered inert or less toxic through processes
such as encapsulation (coating waste materials with an
impermeable substance), solidification, or chemical
stabilization (mixing waste with chemical additives to
render it less harmful or harmless). HWERL researchers
are evaluating solidification and stabilization technologies
to better understand their potential roles in managing
11
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SOURCE CONTROL
hazardous wastes. Studies are attempting to provide
tools for predicting the performance of processes and
products over time, using such parameters as ease of
waste handling, reducing surface area, limiting solubility,
and ability to detoxify pollutants.
• Encapsulation studies are currently examining the
performance of organic binders (epoxides, poly-
esters, vinyls) and inorganic binders (cement, cal-
cium, and silicates).
• Researchers are studying several solidification and
stabilization processes to determine how interfering
organic and inorganic materials affect both the
processes and the products (i.e., the stabilized or
solidified wastes). Areas being studied include the
degree of fixation, durability, and strength; and
resistance to leaching.
Systems Evaluation
Landfills and Surface Impoundments. Evaluations of land-
fill and surface impoundment systems are being made to
determine the relationship between design and actual
construction, to correlate this with potential failure
mechanisms, and to assess whether (and in what ways)
sites may be used for other purposes after closure. To
assist in evaluation, HWERL scientists are combining a
series of computer programs that delineate various
aspects of facility design into one large system that will
review data and calculations for an entire permit appli-
cation, note errors or deficiencies, and recommend
potential solutions. This system should provide more
consistent, rapid turn-around times for these appli-
cations.
In addition, surface impoundments are currently being
explored in order to provide a comprehensive under-
standing of their design, operation, and maintenance.
Researchers are examining the design of dikes, the corre-
lation of laboratory measurements with construction
standards achievable in the field, and the degree to
which specification of construction techniques and
inspection practices may be able to influence uniformity
and performance of finished impoundments.
Underground Storage. Subsurface cavities, particularly
salt formations, have been used as storage depositories
in the United States and Europe for several years. Using
literature review and field demonstrations, HWERL
researchers are assessing technology for the use of
underground mines as possible long-term hazardous
waste storage sites. Factors to be addressed include
mine availability, capacity, and location; surrounding geo-
logical and hydrological conditions; and operational
issues such as transportation, waste handling and place-
ment, and fail-safe back-up systems.
The Removal and Remedial Action Program
HWERL's Removal and Remedial Action Program con-
ducts control development activities in support of
CERCLA (Superfund). This program, which was struc-
tured to match the requirements of CERCLA legislation,
has two components: the Releases Control Branch,
which investigates removal actions (for use in emergen-
cies) and the Containment Branch, which investigates
remedial actions (longer-term cleanup activities).
Because of the frequent necessity for immediate
response to cleanup situations, activities at HWERL do
not always follow the classic path of concept develop-
ment, laboratory evaluation, pilot testing, and field
demonstration. Rather, the program concentrates on
developing and adapting existing technologies, determin-
ing their costs and effectiveness, and producing state-of-
the-art guidance material for use by designers and plan-
ners of uncontrolled hazardous waste site cleanup
activities.
Removal Action
Transportation accidents, mishaps at industrial plants,
and activities at uncontrolled hazardous waste sites can
create emergency situations requiring rapid containment
and cleanup. Each year, hundreds of releases involving
Clean Water Act-designated and CERCLA-designated
hazardous chemicals are reported. Removal action activi-
ties at HWERL concentrate on developing and testing
equipment and procedures to prevent releases, to protect
emergency response personnel, and to assess, contain,
dispose of, and destroy contaminants.
Assessment. Because of the many possible permutations
involving chemical combinations, size of releases, popula-
tions affected, geology, and weather, personnel respond-
ing to emergencies involving hazardous substances may
face diverse technical problems. For this reason, the
development of accurate and rapid assessment tech-
niques has high priority. HWERL scientists and contrac-
tors are developing equipment and procedures to
determine the extent of contamination, the appropriate
extent of cleanup, and priorities within cleanup efforts.
For example, nondestructive testing techniques designed
to locate subsurface releases and chemical containers
are being evaluated, including ground-probing radar, CW
(continuous wave) microwaves, sonics/ultrasonics, and
magnetometer metal detectors. In another project, dogs
are being tested to determine whether their acute sense
12
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SOURCE CONTROL
of smell can be used to pinpoint low levels of chemicals.
Models to determine the performance of physical and
chemical treatment technologies are being designed. A
state-of-the-art manual on removal of hazardous
materials which will provide guidance for identifying,
treating, and disposing of close to 700 designated haz-
ardous substances is being compiled.
Containment/Treatment. Once an accurate assessment
of the situation is made, it is essential to contain,
degrade, and detoxify the contaminants as quickly as
possible in order to prevent or mitigate pollution damage.
At HWERL, alternatives for containing spills are being
developed, as well as techniques for reducing the rate of
liquid spread into spills. These include rapidly deployable
covers to prevent overtopping from rainwater, and stabili-
zation and reinforcement techniques for impoundment
walls and dikes. Equipment being tested and refined
includes mobile incinerators, modular transportable
incinerators, carbon regenerators, and soils washers.
Remedial Action
Hazardous Wastes. Remedial action studies cover the
adaptation, evaluation, and recommendation of technolo-
gies for the containment, concentration, recycling, and
destruction of hazardous wastes. To do this, researchers
take existing technologies, (for example, those used in
the construction, wastewater treatment, and spill
cleanup industries), test their efficacy, and combine them
into cost-effective, long-term cleanup actions. Selecting
the appropriate technology for a specific site is a com-
plex process. A detailed study of site and waste charac-
teristics must be made, and the feasibility of applying
various remedial techniques must be determined.
Contaminated Soils. Contaminated soils are a major prob-
lem at hazardous waste sites. Even a low level or volume
of pollutants can combine with certain land and weather
conditions (for example, high water table, permeable soil
or rock, heavy rainfall) to produce ground-water contami-
nation. Removing contaminated soils and immobilizing
and burying them at another location has several draw-
backs; since landfill and immobilization techniques are
only partly successful, the same problem may simply be
transferred to a different location. Further, communities
are becoming increasingly sensitized to the difficulties
associated with transportation and removal and may
delay or prevent attempts to do so.
Methods of soil cleanup in situ are a promising answer to
these problems. They have not been used extensively at
uncontrolled sites because the technologies are either
still being developed or have not been field-tested.
: \ -
"'••""
»,.*• ••>*•"•
, '-*
Sensor of the future? As part of an EPA pilot project to apply
dogs' acute sense of smell to environmental problems, this
German shepherd has been trained to detect toluene and tri-
chlorophenols in simulated field situations. Because of dogs'
speed and sensitivity (locating as little as 0.2 g of chemical
from distances as great as 50 ft. [15.25 mj), they can out-
perform conventional field instruments. One promising use is
detecting leaks from underground storage tanks.
HWERL scientists and contractors are engaged in testing
and determining the economic feasibility of several
in situ cleanup techniques. Three promising ones are
described below.
• Soils washing involves washing soils with plain
water, solvent, or water plus an additive to remove
contaminants, which are then treated in a separate
facility. Laboratory tests are being conducted on
soils washed with water and water plus surfactants
(such as soaps or detergents). Other studies will
cover pH-adjusted water and solvents (for example,
chelating agent, acid wash).
• Grouting (for example, mixing the waste with a
cement or polymer grout) is one technique to
immobilize contaminants in order to reduce their
rate of release from the soil to an acceptable level.
HWERL researchers are currently studying grouting
techniques and grout-pollutant interactions.
• Precipitation of a highly insoluble compound can
render heavy metals harmless. HWERL scientists are
investigating the development of a process that
uses substances such as sulf ides, carbonates, and
phosphates for this purpose.
13
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SOURCE CONTROL
A major issue for almost all in situ treatment processes is
to develop a means of employing them quickly and effi-
ciently. As one answer, HWERL engineers and contrac-
tors are currently field-testing a prototype mobile in situ
containment and treatment unit (ISCTU). This is a
45-foot-long (14-meter-long) drop-deck trailer capable of
treating approximately 80,000 square feet (7,500 square
meters) of contaminated soil approximately 25 feet (8
meters) deep per month. The system has the capacity to
treat a variety of contaminants in several different soils.
Depending on the needs on site, the ISCTU can:
• Inject a grout curtain into the soil to keep the pollu-
tants from spreading and contaminating ground
water, or to prevent uncontaminated ground water
from entering the waste site.
• Treat the contaminated soil with a variety of tech-
niques such as washing, neutralization, biostimula-
tion, polymerization, oxidation-reduction, and
precipitation.
• Remove contaminated treatment water from recov-
ery wells.
• Air-strip volatile organic contaminants.
The treatment process of choice is continued until a
point of diminishing return is reached. The ISCTU's ver-
satility and its capacity to treat soil to a considerable
depth are a meaningful step in bringing practical, eco-
nomical on site treatment closer to reality.
The EPA In Situ Containment/Treatment Unit (ISCTUi houses a
range of treatment components for detoxifying contaminated
so/'/s. A motor generator set (encased, far left) supplies power
to the system. The trailer's open frame allows ease of move-
ment for workers, while a canvas cover (not shown) provides
protection in inclement weather. Floodlights attached to the
frame make 24 hour operation possible.
14
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3. Prediction
Predicting pollutant behavior in the subsurface is one of
the most difficult—but also one of the most important-
tasks for ground-water protection programs. Many inter-
acting variables can influence the transport and fate of
contaminants: for example, the source of contamination,
the type of pollutant(s), climatic conditions, topography,
and the geological and biological characteristics of the
subsurface. The relative influences of various processes
and conditions on the behavior of a contaminant can
vary, dramatically affecting the accuracy of predictions.
Knowledge of these interactions must be refined in order
to develop and improve mathematical models to predict
chemical transport and fate. In order to gain this knowl-
edge, continued research is needed to obtain representa-
tive samples, to develop more accurate laboratory
simulations (microcosms) of environmental systems, to
conduct field verification studies, to refine tools and
procedures used to measure chemical and physical reac-
tions, and to determine chemistry and biology in situ.
At EPA's Robert S. Kerr Environmental Research Labora-
tory in Ada, Oklahoma (RSKERL-ADA), researchers are
investigating the movement of water in the ground
(hydrogeology) and the various physical, chemical, and
biological attenuation processes that degrade or destroy
contaminants (Figure 9). In addition, RSKERL scientists
and engineers are investigating methods for determining
the mechanical integrity of injection wells, and the inter-
action of injected fluids with geologic materials. This
research has high priority because of the 1984 amend-
ments to the Resource Recovery and Conservation Act
(RCRA). RSKERL staff also offer technical assistance to
personnel in the field. Information about recent findings,
techniques, and technology is disseminated to a broad
professional audience through journal articles, symposia,
training sessions, reports, and guidance documents.
RSKERL also monitors and coordinates the National Cen-
ter for Ground-Water Research (NCGWR), a consortium
of three universities: Rice, Oklahoma State, and the
University of Oklahoma, funded through ORD's Office of
Exploratory Research.
The Environmental Research Laboratory in Athens,
Georgia (ERL-ATH) researches subsurface transport and
transformation processes for organic pollutants and
heavy metals, develops and tests leaching models for
unsaturated zone transport to ground water, and provides
technical assistance and methodology to support pro-
posed RCRA regulations (Figure 9).
Table 2 summarizes current prediction research at RSKERL
and ERL-ATH. Some key projects are described in this
section.
^
Hydrogeologic
Processes
I
• Fluid Flow
• Spatial Variation
• Models
• DRASTIC
Vulnerability
Index
v: /
PREDICTION RESEARCH PREDICTION RESEARCH
Robert S Kerr Environmental
Environmental Research Laboratory
Research Laboratory Athens, Georgia
Ada, Oklahoma
> *. \ / \ /
^ / \
Physical and Chemical Biological Land Banning Pesticide
Processes Processes Decision Tools Leaching
Models
\ / \ :....., / \ /
I
• Sorption • Microorganism
* Volatilization Behavior
• Other Processes
v::.:: .../ \ = /
Figure 9. Highlights of EPA Ground-Water Prediction Research.
15
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PREDICTION
Table 2. Ground-Water Prediction Research
Robert S. Kerr Environmental Research Laboratory— Ada, OK
Environmental Research Laboratory —Athens, GA
AREA OF CONCERN
PROJECT TITLE
PURPOSE
GOALS AND PRODUCTS
Biological Processes Determination of Subsurface
Microbial Activity
Adapt methods such as electron and epifluorescence
microscopy and muramic acid assays to determine
the abundance and metabolic activities of indigenous
microflora in subsurface habitats. Develop methods
to estimate the proportion of metabolically active
bacteria to determine their nutritional state.
Develop improved methods for
identifying and characterizing
subsurface microflora.
Biological Processes
Prediction of Microbial
Contaminant Concentrations
Develop and evaluate predictive models describing
the movement and survival of viruses and patho-
genic bacteria in ground water.
Provide methods and data for
predicting chemical concentra-
tions in ground water at a point
of use.
Hydrogeologic
Processes
Determination of Dispersion
Coefficient Processes
Conduct field investigations to develop an under-
standing of physical and chemical components of
dispersion.
Determine the physical and
chemical components of disper-
sion as used in solute transport
models.
Increase applicability of predic-
tion equations.
Management Aids
Determination of Waste Mobil-
ity by the Use of Microcosms
Evaluate soil profile and aquifer microcosms for their
capacity to predict hazardous waste movement. Test
protocols using selected chemicals from RCRA Sec-
tion 3001. Compare results with field verification
studies.
Develop screening methods to
assess hazardous waste
exposure potential.
Management Aids
Enforcement and Other
Technical Support
Provide consultation, project supervision, testimony,
and analytical support for Superfund activities
involving ground-water contamination.
Provide technical support.
Management Aids
Evaluating Ground-Water
Contamination Risks from
Hazardous Waste Disposal
Investigate the processes that govern the transport
rates, transformation, and fates of hazardous waste
constituents in the subsurface. Evaluate mathemati-
cal models describing solute transport in the subsur-
face. Assess validity through field experiments.
Provide field-evaluated methods
and data to predict concentra-
tions of contaminants from the
treatment, storage, and disposal
of hazardous wastes.
Management Aids
Methods to Determine the
Impact of Geology on Ground-
Water Quality
Develop techniques for determining the impact of
geology, including the impact of surface develop-
ment and water use, on ground-water quality.
Develop methods for detecting geological areas
within an aquifer that should not be developed for
public water use because of naturally occurring con-
taminants such as chromium, selenium, uranium, and
arsenic.
Develop methods for determining
impact of naturally occurring
geological materials and condi-
tions on ground-water quality.
Management Aids
Standard System for Evaluat-
ing Ground-Water Pollution
Potential Using Hydrogeologic
Settings
Develop a protocol to determine the pollution poten-
tial of any United States aquifer or area within an
aquifer based on hydrogeologic criteria. Provide train-
ing and guidance in the use of the protocol.
Provide technical basis for plan-
ning the location of land disposal
sites. Preliminary system has
been published; current field
evaluations will lead to the
development of the protocol.
Management Aids
Support for the Land Disposal
Banning Decision Rule
Assess hydrolytic reactivity and the applicability of a
sorption estimation procedure for selected
chemicals.
Support the Office of Solid
Waste's (OSW) land disposal
banning decision rule required in
the 1984 RCRA reauthonzation.
16
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PREDICTION
Table 2 Cont.
AREA OF CONCERN
PROJECT TITLE
PURPOSE
GOALS AND PRODUCTS
Management Aids
Validation of Predictive
Techniques for Environmental
Exposure
Develop an extensive field data base to establish
parameters to test exposure assessment models.
These models are designed to assess pesticide
migration through the saturated and unsaturated
zones.
Validate pesticide exposure
assessment models, including
PRZM, PESTANS, SESOIL, and
SWAG.
Physical and
Chemical Processes
Mathematical Models for
Subsurface Transport and Fate
Create or modify a range of models for predicting
concentrations of toxic chemicals in the subsurface.
Provide a choice of mathematical
models of contaminant transport
and fate, suitable for a variety of
computers, to aid in estimating
exposure of humans, animals,
and plant life.
Physical and
Chemical Processes
Movement and Persistence of
Dioxins in Soils and Ground
Water
Determine batch sorption isotherms using labeled
dioxins. Evaluate successive additions and extrac-
tions of dioxins to determine desorption characteris-
tics and sorption kinetics in the subsurface. Validate
transport potential using unsaturated microcosms.
Provide capability to predict the
rate of movement and transfor-
mation of dioxins in soils and
ground water.
Assess potential for human
exposure to dioxin.
Physical, Chemical,
and Biological
Processes
Prediction of Chemical
Contaminant Concentrations
Examine sorption/retardation of organic con-
taminants in the subsurface in terms of subsurface
characteristics and organic chemical properties.
Define the subsurface microbial population and
investigate capability to transform organic pollutants.
Study abiotic transformations of organics and con-
centration effects on sorption and transport.
Provide methods and data to pre-
dict concentrations of microbial
contamination in ground water.
Hydrogeologic Processes
Exploring the Complexities of Ground-Water
Contaminant Flow
Contaminant dispersion is a more complex process than
had previously been thought. Until recently, most disper-
sion studies were done in relatively uniform rock or soil
formations, i.e., consisting of one type of material with
few or no changes or discontinuities. Similarly, most
predictive models have been developed for chemicals
that mix readily with water. However, many hazardous
contaminants are not miscible (for example, gasoline,
TCE). They may be either heavier or lighter than water,
and may flow at the same rate as water or less rapidly.
These qualities, alone or combined with geologic discon-
tinuities (for example, fractures, formation changes,
porosity changes) can lead to faster ground-water
recharge and can cause a chemical plume to flow
counter to the mass of water (see Figure 10).
RSKERL scientists are trying to analyze how immiscible
fluids move through porous rock and soil formations, and
how these fluids may physically change a formation's
characteristics, such as permeability, structure, and sorp-
tion capacity. Mathematical tools have been developed to
simulate and predict contaminant transport in plumes
that contain a number of immiscible components, as is
often the case with sources such as hazardous waste
disposal sites, leaking underground storage tanks, and
accidental spills. Another process being investigated is
fractured flow, i.e., the flow of water through fractures or
other discontinuities (caverns, fissures, limestone cavi-
ties) in rock.
The Effect of Spatial Variability on Transport Processes
Another pressing research task is to assess the impor-
tance of the spatial variability of the subsurface on the
transport process. Water and contaminants move in the
subsurface in three dimensions. Movement is influenced
by many physical, chemical, and biological factors that
may change even in a small geographic area. To investi-
gate spatial variability, researchers must answer such
questions as: How many samples are necessary to
describe a hydrologic system, and how can unaltered
samples of subsurface materials be taken? To date, pro-
gress has been slow because of the complexity of the
subsurface and difficulties in obtaining representative
17
-------
PREDICTION
Waste Pile
Land Surface
Water Table
Immiscible Contaminant "B'
Heavier than Water
Immiscible Contaminant "A"
Lighter than Water
Impermeable Formation
Figure 10. Movement Flow of Immiscible Fluids. This idealized drawing illustrates the possible complexities of ground-water
investigation. Immiscible contaminant "A," leaching into an aquifer from a waste pile, is lighter than water and therefore
follows the ground-water flow. Immiscible contaminant "B," entering the aquifer at the same point, is heavier than
water and flows downward until halted by an impermeable formation. At this point contaminant "B" follows the down-
ward slope of the formation and flows counter to the direction of the ground water.
samples. This is an area that requires additional research
in sampling and analysis techniques. A project is planned
to characterize the probability distributions of subsurface
parameters.
Improving Existing Models
Over 400 models now exist to describe the movement of
fluids in the subsurface. These range from simple models
capable of being used with a hand calculator to highly
complex ones requiring a mainframe computer. Each has
its advantages and disadvantages. RSKERL, together
with the International Ground-Water Modeling Center
(IGWMC), maintains a data base on these models, and
works at refining and validating them. Many of these
models are more appropriate for research than for practi-
cal application at this stage. Most transport models are
too general to be helpful in answering site-specific ques-
tions. To rely on these models for developing regulatory
decisions is also problematic, because many are theoreti-
cal and have not been validated. IGWMC scientists are
attempting to improve the reliability of these tools, and to
develop simple, user-friendly models suitable for
managers in field situations.
Assessing Vulnerability to Contamination
Researchers at the National Water Well Association,
under a RSKERL cooperative agreement, have developed
the DRASTIC Index, a tool for evaluating any hydrogeo-
logic setting in the United States for its potential vulnera-
bility to ground-water contamination. A hydrogeologic
setting is defined as a mappable geographic area with
common geologic and hydrologic characteristics. DRAS-
TIC produces a vulnerability rating by ranking the seven
most important factors in any setting: 1) depth to water
18
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PREDICTION
table, 2) recharge, 3) aquifer media, 4) soil media, 5)
topography (slope), 6) impact of vadose (unsaturated)
zone, and 7) hydraulic conductivity of the aquifer.
Because the evaluation is relative rather than absolute,
DRASTIC is designed to be used for planning or screen-
ing. However, the DRASTIC concepts are key to the
development of EPA Ground-Water Protection Strategy
vulnerability guidelines and subsequent regulations.
DRASTIC is now being applied to index ten areas of the
United States in order to ensure its applicability in a wide
variety of hydrogeologic settings.
Pesticide Leaching Models
Pesticide contamination of ground water is a growing
concern, particularly because of its possible connection
to agricultural practices such as conservation tillage.
Because conservation tillage is considered the best soil
protection method and possibly the best management
practice to improve surface water quality, estimates indi-
cate that it will be used for 95 percent of row crop acre-
age by the year 2000. However, the increased pesticide
application rate, increased infiltration rates of water, and
the use of soluble, persistent pesticides associated with
conservation tillage pose considerable potential danger to
ground-water supplies.
Scientists at the Environmental Research Laboratory in
Athens, Georgia (ERL-ATH), and at RSKERL have devel-
oped two leaching models to screen pesticides for their
potential to contaminate ground water: Pesticide Analyti-
cal Solution (PESTANS) and Pesticide Root Zone Model
(PRZM). A methodology for screening pesticides for their
potential to migrate in various geographic areas, called
Leaching Evaluation of Agricultural Chemicals (LEACH),
has been produced by running PRZM through a spectrum
of possible soil/crop/weather agricultural scenarios in the
United States. Early efforts to validate PESTANS and
PRZM were retrospective performance tests associated
with specific applications for regulatory purposes, rather
than actual scientific validation. Current validation efforts
include the Dougherty Plains project, in which the actual
migration of two pesticides, Temik and Dual, through
sandy, layered soil growing a peanut crop, is compared to
the projections of PESTANS, PRZM, and other first-
generation leaching models. The project is designed to
provide rigorous evaluation of these models over the next
several years.
Research to Support Proposed RCRA Land Banning
Regulations
The newly reauthorized RCRA requires EPA to develop
criteria to determine whether land disposal of hazardous
At the Dougherty Plains Project, several vacuum-pressure
lysimeters (projecting teflon tubes shown in left foreground^ are
being installed. The lysimeters will be buried in this field and
then unearthed after crop planting and pesticide application so
that soil-water samples can be tested for levels of
contamination.
wastes adequately protects human health and the envi-
ronment, and to determine if certain wastes should be
banned from land disposal. In EPA's proposed regula-
tions, the rule for evaluation of ground-water contamina-
tion and potential human exposure requires certain
contaminant-specific and environmental characterization
data. Implementing this rule for the approximately 450
contaminants now on the RCRA list requires the fol-
lowing information:
• For chemicals:
- hydrolysis rate constants (sorbed and dissolved)
- partition coefficients
• For metals:
- thermodynamic and sorption data bases sufficient
for speciation calculations
• For all contaminants:
- appropriate environmental characterization
- appropriate assessment methods
For each contaminant, data will be incorporated into a
ground-water/surface water model developed for this
purpose. In each case, using this model/data combination
requires a thorough uncertainty analysis to better defend
the specific parameter choices, and to better understand
the range of possible outcomes. The ERL-ATH laboratory
is providing the EPA's Office of Solid Waste (OSW) with
contaminant-specific data, as well as giving technical
assistance in the development, technical defense, and
application of the proposed rule.
19
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PREDICTION
Physical and Chemical Processes
Sorption
Adapting Surface Models to Describe Subsurface
Phenomena. Once a contaminant has entered the sub-
surface, it is subject to various physical and chemical
attenuation processes such as sorption, hydrolysis,
reduction, substitution, and volatilization. Investigation at
RSKERL and at extramural projects has concentrated on
sorption (chemical or physical processes of adherence or
assimilation). Sorption processes may be complex. Many
existing theories and models of sorption processes were
developed for surface soils and do not take into account
the special nature of ground-water scenarios. For exam-
ple, several theories have been based on surface soils
that contain a relatively large carbon content; thus, they
do not address subsurface geologic conditions, where
the carbon content is often low, or where the ratio of
clay soil to carbon is high, altering potential sorption
capabilities. RSKERL scientists are studying surface sorp-
tion models of hydrophobic organic pollutants to adapt
them to ground-water conditions.
Developing New Models for Subsurface Phenomena.
Scientists must also assess how well current sorption
theory predicts how the subsurface might change the
characteristics of contaminants or how contaminants
change the characteristics of the subsurface. For exam-
ple, certain organic solvents will change the chemistry of
some clays that line lagoons and will then leach through
these clays. This kind of scenario might be found in the
subsurface, where, for example, a contaminant might
interact with a clay stratum that covers a confined
aquifer, and then migrate through to contaminate the
aquifer. RSKERL scientists and extramural researchers
are quantifying the various interactions possible in the
subsurface in complex but realistic simulations of
environmental systems in order to develop theories and
predictive models to describe sorption.
Investigating the Rate of Sorption. Another important
aspect of sorption research is the rate at which sorption
occurs. Most models assume the process is instanta-
neous. Laboratory and field experiments have shown this
to be largely untrue, but current theories devised to
explain the dynamics of slower sorption rates do not ade-
quately describe the behavior of many environmentally
significant chemicals. RSKERL and contract scientists are
refining these theories and developing others to more
accurately explain sorption rate.
Two RSKERL staff members use a hollow stem auger to obtain
a soil core sample for laboratory study. Researchers may exam-
ine a soil to determine its physical constituents, its hydraulic
properties, the extent and activities of its microbial populations,
and other information that may aid in understanding con-
taminant behavior in ground water.
Volatilization
Another process that needs to be studied is volatilization.
How much of a contaminant is volatilized and lost
through the unsaturated zone? How important is this
process in the eventual fate of a contaminant? In an
attempt to answer these questions, RSKERL scientists
and extramural researchers are studying volatilization in a
closed system.
20
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PREDICTION
Future Directions
Almost no field information exists on transformation
processes such as hydrolysis, reduction, complexation,
and substitution in organic chemicals and heavy metals
in ground water. Because ground water moves slowly,
processes such as these, which can take several years to
occur, may turn out to be the most significant in pollu-
tant attenuation. The greatest impediment to the study
of physical and chemical processes in the subsurface is
the lack of techniques and equipment for measuring
chemistry in situ. Tools and procedures must be devel-
oped to determine the potential for reactions and to
measure their extent.
The particular species of a metal has a dominant
influence on the metal's transport and transformation in
ground water. Metals may exist in different oxidation
states or in complexes with various organic chemicals.
Determining the influence of speciation on metal move-
ment is a new area of research at the RSKERL and ERL-
ATH laboratories.
Biological Processes
RSKERL researchers and extramural contractors are
studying the transport and fate of organic solvents and
pathogens in ground water. In surface soils and waters,
microorganisms play the primary role in transforming
organic compounds. Their role in the subsurface, how-
ever, is largely unknown, although some promising dis-
coveries have been made. Initial findings by the scientific
community have shown that there are microorganisms in
both the shallow and deep subsurface; that these
microorganisms may vary considerably in both type and
number; and that some are capable of degrading certain
chemicals of interest. In fact, while it was previously
assumed that the subsurface held no life, scientists now
think that the total biomass in regions below the root
zone in North America is probably much higher than the
bacterial biomass in rivers and lakes.
Now that these general questions have been partially
answered, researchers must continue to examine subsur-
face microbes and their degradation ability by asking
more specific questions such as: What do they do?
When? Where? How much? How fast? Under what con-
ditions? What are the by-products? How can their
behavior be predicted? For example, it is now known that
organisms in the subsurface can transform many impor-
tant organic pollutants. The rate of transformation is
limited by the number and activity of the microorgan-
isms, while the extent of transformation is most fre-
By examining bacterial populations in the subsurface, scientists
learn more about biological influences on contaminant behavior.
This bacterial cell, from a soil core taken at 18 feet (5.6 m) by
RSKERL researchers at Fort Polk, Louisiana, is unusual for the
sample population because of its small size and particular
structure. The dark area with the white hole is a storage
granule—bacteria use mechanisms like this to store material
needed for survival or growth. Long periods of scarce nutrient
supplies in the subsurface may have caused the development of
such adaptive mechanisms.
quently limited by requirements for metabolism such as
oxygen or mineral nutrients. However, these conclusions
are based on a limited number of studies.
RSKERL scientists are furthering this knowledge by
investigating the relationship between organisms and
their particular environment (for example, depth, geology,
mineralogy). They are also studying other factors, such
as the processes and conditions that encourage or limit
biodegradation. For example, extramural researchers are
investigating the activities of hepatitis A virus (HAV), a
major pathogen that causes severe gastroenteritis and
intestinal infections. Until a few years ago, scientists
were unable to identify and isolate HAV in the laboratory.
The recently developed ability to assay for HAV has
enabled researchers to initiate studies to determine how
long the virus retains its infective capacity in a variety of
soils and water samples. This is a first step toward
assessing what physical, chemical, and biological
changes HAV and other viruses may undergo in ground
water.
21
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4. Monitoring
Monitoring provides information on potential or known
contamination. Many types of monitoring may be per-
formed for a variety of reasons; for example, monitoring
may be used to determine probable contaminant path-
ways, to map actual contaminant flow, to locate sources
of contamination, to identify contaminant plumes, and to
detect leaching, percolation, or leaks. Monitoring
research, conducted at the Environmental Monitoring
Systems Laboratory in Las Vegas, Nevada (EMSL-LV),
with assistance from the Robert S. Kerr Environmental
Research Laboratory in Ada, Oklahoma (RSKERL-ADA),
focuses on developing ground-water monitoring and
sampling techniques and geophysical monitoring tech-
niques, and refining methods for interpretive analysis of
data (Figure 11). These techniques and methods are used
to define the nature, location, and movement of subsur-
MOIMITORING RESEARCH
Environmental Monitoring
Systems Laboratory
Las Vegas, Nevada
Fiber
Optics
Ground-Water
Variance Analysis
Well
Construction
MONITORING AND
SAMPLING
INTERPRETIVE
ANALYSIS
GEOPHYSICAL
MONITORING
TECHNIQUES
Aerial Photo
Analysis
Indicator
Parameters
Vadose Zone
Monitoring
Downhole Sensing
Soil-Gas
Monitoring
Deep Plume
Sensing
Figure 11. Highlights of EPA Ground-Water Monitoring Research.
22
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MONITORING
face contamination. Table 3 lists current monitoring
projects. The laboratories also provide operational
guidance and technical support to EPA program and
regional offices, and to state and local agencies.
Research findings are communicated to the user
audience through guidance documents, journal articles,
workshops, and training courses.
Table 3. Ground-Water Monitoring Research
Environmental Monitoring Systems Laboratory — Las Vegas, NV
Robert S. Kerr Environmental Research Laboratory—Ada, OK
AREA OF CONCERN
PROJECT TITLE
PURPOSE
GOALS AND PRODUCTS
Monitoring and
Sampling
Geophysical Surveys of
Hazardous Waste Sites
Provide geophysical and geochemical monitoring support
to EPA regional offices and EPA's Emergency Response
Team for assessment of CERCLA hazardous waste sites.
Meet RCRA land disposal regula-
tions for ground-water detection
and compliance monitoring for con-
taminants leaking from permitted
facilities.
Provide cost-effective monitoring
techniques.
Support remedial and removal
actions at CERCLA sites.
Establish standard procedures for
the application of geophysical and
geochemical techniques.
Conduct geophysical surveys on
request.
Monitoring and
Sampling
Ground-Water Quality
Protection from
Injection Wells
Test the mechanical integrity of injection wells. Develop
an overview of contamination cases associated with
Class II and V injection wells.
Provide technical support in the
implementation of Underground
Injection Control (UIC) regulations.
Monitoring and
Sampling
Methods for Monitoring
Well Construction
Assess alternative methods for constructing monitoring
wells to determine problems with surface and subsur-
face contamination; select and field-test recommended
monitoring options.
Determine and recommend pre-
ferred well drilling and sealing tech-
niques to derive accurate
ground-water samples.
Monitoring and
Sampling
Monitoring Ground
Water with Fiber Optics
Technology
Evaluate the feasibility of performing contaminant-
specific ground-water monitoring using fiber optics tech-
nology combined with laser fluorescence spectroscopy.
Develop methodology and hardware
to monitor organic and inorganic
chloride concentrations.
Conduct field demonstration to
identify weaknesses in the
methodology.
Improve response time and lower
cost of monitoring technology.
Monitoring and
Sampling
Unsaturated Zone
Monitoring for
Hazardous Waste Sites
Evaluate agricultural equipment and methods for
monitoring in the vadose zone to detect leaching and
percolation of pollutants from hazardous wastes. Deter-
mine the relative effectiveness of suction and gravity
lysimeters.
Adapt existing technology to meet
RCRA regulations for monitoring at
permitted land treatment or land
farming disposal areas.
Provide guidance for lysimeter per-
formance for permit writers.
Develop technical resource
document on unsaturated zone
monitoring at hazardous waste land
treatment units.
Monitoring and
Sampling
Well Construction and
Sampling for Ground-
water Quality Analyses
Develop methods for constructing, completing, and sam-
pling ground-water monitoring wells to obtain represen-
tative physical, chemical, and biological data.
Update manual for sampling
ground-water quality parameters.
23
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MONITORING
Table 3 Cont.
AREA OF CONCERN
PROJECT TITLE
PURPOSE
GOALS AND PRODUCTS
Geophysics
Detection of Leachate
Plumes in Ground Water
with Geophysics
Evaluate geophysical and geochemical methods to
detect and map organic and inorganic leachate plumes at
hazardous waste sites, emphasizing soil-gas sampling
techniques for mapping organic plumes.
Establish guidelines for the number
of sample points required to map a
plume.
Develop quality assurance guide-
lines for the calibration of equip-
ment and procedures for mapping
hazardous waste sites.
Provide guidance on the application
of geophysical and geochemical
techniques to hazardous waste
sites.
Recommend procedures for hazard-
ous waste site investigations.
Geophysics
Downhole Sensing for
Hazardous Waste Site
Monitoring
Design, build, modify, and evaluate sensing devices and
methods used to obtain geohydrologic data from
monitoring wells.
Develop new technology or modify
existing technology for typical
small-diameter, shallow-depth,
plastic-cased monitoring wells.
Develop procedural manual for use
by site operators and regulatory
personnel.
Make conference presentations on
project efforts.
Geophysics
Geophysical Sensing of
Fluid Movement from
Injection Wells
Map the migration of wastes from injection wells at
depths of 1,000+ feet at several field sites, using the
time-domain electromagnetic method.
Assess the applicability of time-
domain EM technology to meet
Underground Injection Control (UIC)
regulation requirements.
Develop a technical transfer report.
Interpretive Analysis
Locating Abandoned
Wells with Historical
Photographs
Identify abandoned oil and gas wells through historical
aerial photographs and verify by comparison with
conventional records.
• Assist EPA regional officials in
examining large areas for aban-
doned gas and oil wells to comply
with UIC regulations.
• Provide reports with area maps
indicating photo-identified oil and
gas well locations.
Interpretive Analysis
Indicator Methods for
Ground-Water Detection
Monitoring
Determine parameters that indicate the presence of haz-
ardous constituents in ground water at land disposal
sites, using existing data from Consent Decree, Super-
fund, and RCRA site monitoring files.
Evaluate performance of selected
indicator parameters.
Meet RCRA requirements for detec-
tion and compliance monitoring as
part of land disposal ground-water
monitoring programs.
Identify "missed classes" of haz-
ardous constituents.
Develop a short list of parameters
that are (1) reliable indicators of
leakage, and (2) inexpensive to
measure
Interpretive Analysis
Variance Analysis for
Ground-Water Quality
Monitoring
Determine the variability over time of ground-water
monitoring data, using several statistical techniques.
• Develop a reliable, statistically
sound, technical basis for the
design and implementation of
monitoring networks.
24
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MONITORING
Monitoring and Sampling
Monitoring and sampling research involves developing
innovative techniques and equipment, refining existing
techniques, and adapting those from allied industries.
Fiber optics, well-drilling techniques, and soil sampling
devices are currently being investigated by EMSL and its
contractors.
Fiber Optics
Fiber optics is one of the most promising areas being
investigated for contaminant monitoring. A major break-
through in this research has been the development of a
spectrometer (Figure 12) for remote analysis of con-
taminants through the integration of fiber optics, lasers,
chemistry, optrodes, and spectroscopy. The key element
is the optrode. This tiny sensor, placed at the end of an
optical fiber, can measure concentrations of certain
chemicals and transmit this information back to the
spectroscope in the form of fluorescent light. The use of
a single fiber to send and return light is an important
design advantage, since it allows the optrode size to be
reduced and minimizes optical alignment and focusing
problems at the sampling end.
The organic chloride optrode, which consists of an optical fiber
immersed in chloride-reactive chemicals, is housed in a narrow
glass tube sealed with a membrane that keeps the chemicals
in, water and din out, and allows volatile organic chlorides to
pass through. This sensor, encased in its protective metal
shield, could be dropped down a monitoring hole smaller in
diameter than a quarter.
The optrode that is currently being tested monitors vola-
tile organic chloride compounds in ground water and in
the unsaturated zone. Research to date indicates sensi-
tivity to concentrations of less than 50 parts per billion
at remote distances of up to 656 feet (200 meters)
Excitation Light
o
Returning
Fluorescence 0pt|Ca| Rber
Figure 12. A Schematic Representation of Remote Fiber Spectroscopy.
25
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MONITORING
Figure 13. Remote Fiber Fluorimetry Can Be Used to Measure
Chlorinated Hydrocarbons in Ground Water.
(Figure 13). The instrument has several advantages over
conventional monitoring devices; not only is it simpler
and more economical, it is also extremely versatile. It can
be used to sample at sites (generally wells) that are hot,
cold, radioactive, dangerous, and/or hard to reach. Its
flexibility, small size, and ruggedness make it extremely
useful for situations that require multiple probes that can
read continuously for long periods of time, and are
unaffected by other chemicals or equipment. For exam-
ple, optrodes could be used as part of an "early warn-
ing" system to monitor a hazardous waste site for
incipient signs of contamination. Since the optrode may
be left in place and remain effective for as long as
12 months, it is particularly suitable for long-term
monitoring.
The optrode's primary limitation at this time is the
number of chemicals it can measure. Although in theory
the number is limitless, in practice the optrode can
detect only a few chemicals with sufficient accuracy.
Selection, adaptation, or development of suitable chemi-
cal systems designed for optrodes will be the next major
goal for researchers.
Improved Well Construction
In another project, EMSL researchers and contractors are
investigating the extent to which drilling techniques and
sealing materials commonly used for both domestic
water well and monitoring well construction contribute to
contaminant dissemination. As a first step, they are
examining and testing conventional drilling methods —
particularly the hollow stem auger and mud and air
rotaries —so that problems in use can be categorized and
more effective drilling and sealing techniques
recommended.
Vadose Zone Monitoring
At permitted land treatment or land farming disposal
areas, RCRA regulations require monitoring of the vadose
(unsaturated) zone to detect leaching and percolation of
pollutants before they reach the water table. Standard
sample collection devices used in agriculture (for exam-
ple, lysimeters) are being examined for modification for
use at land treatment or disposal sites. Lysimeters collect
water from soils; the water is then analyzed for soluble
constituents. Two lysimeters—the suction cup, which
collects liquid through a permeable ceramic cup, and the
gravity lysimeter, which collects water that flows down-
ward as a result of gravity—are being compared for per-
formance and effectiveness in various different types of
soils in laboratory and field studies.
Geophysical Monitoring Techniques
Geophysical and geochemical techniques for detecting
and mapping subsurface contamination, such as ground-
penetrating radar, electromagnetic induction, resistivity,
rnagnetometry, and seismic surveys are currently being
investigated by EMSL researchers and support contrac-
tors. One or a combination of techniques may be used
for monitoring, depending on such factors as the nature,
depth, and location of the contaminant.
Soil-Gas Sampling and Deep Plume Sensing
Specific investigations include the use of soil-gas
sampling (a technique useful for organic contaminants)
to locate a gasoline-spill plume in Stove Pipe Wells,
California. Also being evaluated is time-domain electro-
magnetometry, which shows potential for mapping of
deep plumes (2,000 to 4,000 feet [610 to 1,220 meters])
at test sites where salt water has migrated from injection
wells.
Downhole Sensing
In another area of investigation, devices designed for
industrial monitoring are being modified for ground-water
monitoring. For example, EMSL and contract engineers
are adapting and redesigning downhole sensing devices
used in the deep, wide, uncased wells drilled for
petroleum exploration, to be useful in ground-water
monitoring wells, which are typically narrow, shallow,
and encased in plastic. One of these devices —a meter to
measure water flow and direction —is being evaluated in
both laboratory and field tests.
26
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MONITORING
Interpretive Analysis
Because monitoring investigations typically involve con-
siderable effort and expense, one important aspect of
monitoring investigation is the synthesis of existing infor-
mation on contamination and, where applicable, the anal-
ysis of correlative data.
Aerial Photography Analysis
Historic aerial photographs have proved useful in locating
abandoned oil and gas wells in Oklahoma. Since Under-
ground Injection Control (UIC) regulations require identifi-
cation of abandoned wells around proposed injection
sites, scientists at EMSL are available to examine photo-
graphs of possible abandoned well sites upon request
from EPA regional offices. "Signatures" of abandoned
wells, composed of artifacts such as building founda-
tions, scars of access roads, and mud pits are developed
from the photographs. Identification is then checked
against old records to determine accuracy.
Indicator Parameters
Using existing RCRA and CERCLA monitoring data,
researchers are developing and testing indicator parame-
ters (such as temperature, pH, specific conductance, and
total organic carbon [TOC]) to assess the occurrence of
contaminant leakage from land disposal facilities into
ground water.
Variance Analysis
Another technique being evaluated is variance analysis,
which will be used to assess the variability of ground-
water monitoring data over time to assist in the design of
large-scale monitoring networks.
Aerial photographs of the same well sites in Arcadia, Oklahoma, over a span of 24 years. The photo on the left, taken in 7957,
shows several active wells (indicated by arrows) located near surface impoundments. In the photo on the right, taken in 19 75,
remnants of the impoundments remain, but the abandoned well locations have become indiscernible as roads and well sites have
become covered with vegetation.
27
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5. In Situ Aquifer Cleanup
Restoring a polluted aquifer is generally an extremely
expensive enterprise. Nevertheless, in some instances,
restoration is the option of choice; for example, when
there is no other local drinking water source, when the
cost of transporting water from an alternative source
equals or surpasses the cost of restoration, or when the
damage to the aquifer has serious human health or eco-
logical implications. The decision to attempt restoration
of a polluted aquifer is rarely simple or clear-cut. Techni-
cal feasibility is only one aspect to consider, and is often
not the most pressing one. Economic, health, social,
political, and other factors must be weighed against one
another.
Until a range of inexpensive, effective cleanup methods is
developed, managers who must decide whether to restore
an aquifer face a series of difficult decisions. Serious
thought, good management skills, and a solid information
base are required. To meet these needs, researchers at
RSKERL are concentrating on two approaches to improve
existing cleanup methods: they are examining ways of
making restoration techniques less expensive and more
easily applicable, and they are examining case histories
of restoration efforts to identify factors that influenced
their success or failure (Figure 14). From this base, they
will develop guidelines for decision-making. Table 4 sum-
marizes current research projects at RSKERL. Some key
projects are described below.
Case Histories and Cost-Benefit Analyses
RSKERL researchers and contractors are using literature
searches, information from regulatory officials, and case
studies to explore the issues involved in aquifer cleanup.
One study reviews case histories of contaminated
IN SITU AQUIFER CLEANUP
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma
Case Histories and
Cost-Benefit Analyses
Technology
Figure 14. Highlights of EPA In Situ Aquifer Cleanup Research.
aquifers, identifies the technology used for restoration in
effective cases and, where cleanup was not effective,
devises successful alternative scenarios. Issues that
influence cleanup decisions, such as cost and feasibility,
plus social, political, and institutional problems are being
examined.
Another study compares the incremental costs and
benefits of cleaning up waste sites. In addition to using
historical information, researchers are assessing cleanup
activities at two active Superfund sites by studying the
options for remedial actions and the factors that
influence choices. For decision makers at the policy level,
management experts are designing systems to address
general issues; for example, a hierarchical decision-
making set is being developed to answer the question
"How clean is clean?" For operational managers, a hand-
book is being prepared which will provide guidelines on
decisions about aquifer cleanup, such as how to assess
whether cleanup is the preferred option, what cleanup
methods to use in various circumstances, and how to
estimate costs.
Technology
Biodegradation of contaminants is one of the most
promising techniques for aquifer cleanup. RSKERL is
sponsoring several studies that investigate the biological
processes leading to contaminant degradation, and is
examining ways to enhance these processes, with the
aim of creating economical in situ treatment techniques.
Bacteria as Plasmid Hosts
RSKERL and contract scientists are exploring the possi-
bilities of stimulating degradation in populations of
ground-water bacteria. One extramural study is attempt-
ing to devise reliable methods to enable ground-water
bacteria to "host" plasmid DNA, a key factor in bio-
degradation. Plasmid DNA, or plasmid, is genetic material
that carries information not required for life processes.
Because certain plasmids carry instructions on how to
destroy contaminants, they are important in all environ-
mental research. Some plasmids contain codes that
instruct on how to destroy specific contaminants, such
as toluene, PCBs, DDT, and ethyl benzene. Others, some-
times called "superplasmids", contain information on the
destruction of several contaminants. While some bacteria
can destroy contaminants without plasmids, others must
incorporate, or "host" plasmids, and receive their
instructions before they can be effective. Hosting can
only occur when certain conditions exist, such as a mini-
mum bacteria population size and sufficient nutrients.
28
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IN SITU AQUIFER CLEANUP
A photomicrographed section of DNA containing the
curvilinear-shapedp/asmidpSS 50 (magnified 27,000 times),
isolated from an Alcaligenes bacterium, and a sketch of pSS 50
taken from the photograph. This p/asmid contains instructions
for the biodegradation of some polychlorinated biphenyls
(PCBs).
Extensive investigations of the bacteria/plasmid relation-
ship have been made in soil and surface water, but
ground water raises unique issues. Like the mysterious
aquatic life that exists at great oceanic depths, ground-
water bacteria are largely unknown phenomena. Scien-
tists must ask basic questions about their behavior and
environment, such as: Are there plasmids in ground-
water bacteria? Can bacteria host plasmids? Can plas-
mids be inserted successfully into the ground-water
environment? If so, will the bacteria accept them?
To determine answers, scientists are studying bacteria
from an actual aquifer in a pure culture medium in the
laboratory and in a simulated aquifer environment, and
then introducing toluene plasmids to see whether host-
ing will take place. The development of a technique to
detect specific plasmids in populations of bacteria is an
important general research contribution that will prove
Bacteria of the Arthrobacter species (a microcolony is shown
here, magnified 38,000 times by electron microscopy) are natu-
rally able to degrade styrene, an industrial contaminant. Univer-
sity scientists under contract to EPA are using genetic
manipulation in attempts to enable the bacteria to degrade
other contaminants.
useful in this study. However, some new techniques must
be developed, for example, methods to detect plasmids in
ground water. Scientists hope that this type of research
will ultimately lead to a formula, or recipe, to create
effective bacterial "armies" to fight contaminants.
TCE Biodegradation
The organic contaminants most commonly detected in
ground water are chlorinated aliphatic hydrocarbons such
as trichloroethylene (TCE), tetrachloroethylene (PCE),
1,1,1-trichloroethane, carbon tetrachloride, and chloro-
form. This class of compounds has been resistant to bio-
degradation in aerated subsurface environments. Current
technology for removing these pollutants involves pump-
ing the water to the surface and air-stripping the com-
pounds in aeration towers or removing the pollutant on a
sorbent. An in situ process that would degrade the con-
29
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IN SITU AQUIFER CLEANUP
Table 4. In Situ Aquifer Cleanup Research
Robert S. Kerr Environmental Research Laboratory — Ada, OK
AREA OF CONCERN
PROJECT TITLE
PURPOSE
GOALS AND PRODUCTS
Case History/Cost-
Benefit Analysis
Methods for Protecting Public
Water Supplies from Existing
Ground-Water Contamination
Determine cost-effectiveness and feasibility of alter-
nate aquifer cleanup methods by examining social,
political, institutional, and technical issues in case
studies.
Provide states and localities with
methods of assessing technology
to protect public water supplies.
Case History/Cost-
Benefit Analysis
Analysis of Cost-
Effectiveness of Aquifer
Restoration Techniques
Evaluate incremental benefits versus incremental
costs of cleaning up a range of waste sites, consider-
ing political, social, economic, and medical issues, as
well as cleanup effectiveness.
Determine the effectiveness of
various aquifer restoration
techniques.
Develop hierarchical decision-
making set to determine "how
clean is clean?"
Technology
Feasibility of Enhancing the
In Situ Biodegradation of
Contaminants in Ground
Water
Detect the presence of plasmid DNA in ground-water
bacteria and evaluate the ability of ground-water bac-
teria to act as hosts for specific plasmid DNA associ-
ated with biodegradation. Evaluate the behavior of
the plasmids in subsurface material.
Evaluate the feasibility of enhanc-
ing in situ biological degradation
of ground-water contaminants
Technology Laboratory and Field Evalua-
tion of Methodology for
In Situ Aquifer Restoration
Evaluate selected cleanup methods, including physi-
cal removal, chemical treatment, and enhanced bio-
degradation for feasibility and cost-effectiveness.
Develop cleanup protocols using
the results of the project.
Develop the process for aerobic
degradation of TCE (tnchloro-
ethylene) for use in the field.
Technology
Simulated Aquifer
Restoration
Test aquifer restoration methods under simulated con-
ditions by creating an artifical aquifer that can be
mathematically represented
Use artificial aquifer systems to
develop aquifer restoration
methods.
Technology Monitoring the Development
of Active Subsurface Organ-
isms During Bioreclamation
of Polluted Aquifers
Evaluate existing methods for determining the popula-
tion sizes of bacterial groups that may be used to
biodegrade contaminants in aquifers.
Increase scientific information
that will lead to effective
bioreclamation techniques.
taminants rather than transferring the problem to another
location would be a more effective and economical treat-
ment. One area being studied is the use of microorgan-
isms to degrade specific contaminants. To investigate
this possibility, RSKERL scientists, in a laboratory experi-
ment, enriched soil from the unsaturated zone with natu-
ral gas to stimulate microbial activity, and then added
water containing TCE. TCE was degraded to carbon diox-
ide, and the concentration of TCE was reduced signifi-
cantly—by one order of magnitude in a two-day period —
an adequate rate for reclamation in situ. Researchers are
now working on identifying other chlorinated aliphatic
hydrocarbons responsive to the process, determining
other end products, and adapting the process for use in
aquifers.
Contamination issues and techniques may be examined
in the laboratory or in the field. Field studies have the
advantage of allowing scientists to observe techniques
and activities under actual, variable, "real-life" condi-
tions. One such study will locate a contaminated aquifer
amenable to rehabilitation, and assess the effectiveness
of a variety of methods, such as physical removal, chemi-
cal treatment, and enhanced biodegradation for cleanup.
Cleanup protocols will also be developed. One of the
techniques used will be the aerobic degradation of TCE
described above.
30
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6. Information Transfer and
Technical Assistance
Activities
Transmitting information about current research to deci-
sion makers, field managers, and the scientific commu-
nity is an important part of EPA's ground-water research
programs. New research findings are communicated
directly to the scientific, technical, and management
community via information transfer mechanisms such as
articles, documents, symposia, conferences, and training
programs. In addition, ORD staff offer technical
assistance to a variety of sources (for example, EPA
regional and program offices, other Federal agencies,
state agencies) to solve specific environmental problems.
The Robert S. Kerr Environmental Research Laboratory
(RSKERL) conducts many information transfer activities
and, in recent years, has provided technical assistance at
field investigations at over a dozen hazardous waste sites
in nine states. At the Environmental Monitoring Systems
Laboratory (EMSL), technical support investigations and
training in geophysics are an important part of laboratory
activities. Hazardous Waste Engineering Research
Laboratory (HWERL) researchers provide scientific infor-
mation and analysis in support of corrective actions at
Superfund sites, as well as producing a series of techni-
cal handbooks on source control technology in support
of CERCLA, and technical resource documents (TRDs) on
specific areas of landfill design. HWERL has also recently
established the Technical Information Exchange (TIX), a
specialized reference center that provides state-of-the-art
information on hazardous waste cleanup and emergency
response technology. The Environmental Research
Laboratory in Athens, Georgia (ERL-ATH), in addition to
its technical support for the 1984 RCRA amendment land
disposal banning rule, maintains the Center for Water
Quality Modeling. This center provides and distributes
models, maintains data bases on soils, chemicals, and
other information, and develops manuals and offers train-
ing courses to support model use. Tables 5 and 6 list
selected current research-related publications and meet-
ings for these four laboratories.
Table 5. Information Transfer and Technical Assistance
Selected Recent Publications1
AREA
Source Control
Prediction
Monitoring
In Situ Aquifer
Cleanup
SPONSOR
HWERL/CIN
HWERL/CIN
HWERL/CIN
HWERL/CIN
HWERL/CIN
HWERL/CIN
ERL/ATH
ERL/ATH
ERL/ATH
HWERL/CIN
RSKERL/ADA
RSKERL/ADA
RSKERL/ADA
RSKERL/ADA
EMSL/LV
EMSL/LV
EMSL/LV
RSKERL/ADA
EMSL/LV
RSKERL/ADA
RSKERL/ADA
RSKERL/ADA
TITLE
Batch Soil Procedure to Design Clay Liners for Pollutant Removal (TRD)2
Design, Construction, Maintenance, and Evaluation of Clay Liners for Hazardous Waste Facilities (TRD)
Hydrologic Evaluation of Landfill Performance (HELP) Model (TRD)
Methods for the Prediction of Leachate Plume Migration and Mixing (TRD)
Soil Properties, Classification, and Hydraulic Conductivity Testing (TRD)
Solid Waste Leaching Procedures Manual (TRD)
Leaching Evaluation of Agricultural Chemicals (LEACH) Handbook
Users Manual for the Pesticide Root Zone Model (PRZM)
| Modeling Remedial Actions at Uncontrolled Hazardous Sites (Guidance Manual)
DRASTIC: A Standardized System for Evaluating Ground Water Pollution Potential Using Hydrogeologic
Settings (Report)
Evaluation of Septic Tank System Effects on Ground-Water Quality (Report)
Ground-Water Transport: Handbook of Mathematical Models (Report)
Methods for Protecting Public Water Supplies from Existing Ground-Water Contamination
Geophysical Techniques for Sensing Buried Wastes and Waste Migration Manual
Guidance Manual for Vadose Zone Monitoring at Land Treatment Facilities (Manual)
1 A Guide to the Selection of Materials for Monitoring Well Construction and Ground-Water
j Methods for Determining the Location of Abandoned Wells (Report)
Methods for Determining the Mechanical Integrity of Class II Injection Wells (Report)
State-of-the-Art Aquifer Restoration Methods (Report)
(Report)
Sampling (Report)
'Published in 1985. For information on other publications, contact individual laboratories or the EPA Center for Environmental Research Information ICERI), Cincinnati,
OH.
2TRD = Technical Resource Document.
31
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INFORMATION TRANSFER AND TECHNICAL ASSISTANCE
Table 6. Information Transfer and Technical Assistance
Symposia, Conferences, and Training Programs— 19851
AREA
Source Control
Prediction
Monitoring
In Situ Aquifer
Cleanup/
Monitoring
SPONSOR
CERI2
HWERL/CIN
HWERL/CIN
HWERL/CIN
HWERL/CIN
HWERL/CIN
RSKERL/ADA
RSKERL/ADA
RSKERL/ADA
EMSL/LV
EMSL/LV
EMSL/LV
RSKERL/ADA
EMSL/LV
TITLE
Protection of Public Water Supplies from Ground-Water Contamination (EPA Technology Transfer
Annual Oil Spills Conference
Eleventh Annual Conference on the HWERL Research Program
First International Conference on New Frontiers in Hazardous Waste Management
Superfund Technical Handbooks (Regional Training)
Source Control Technology for EPA Regions, EPA Contractors, and States (Workshops)
Seminars)
Modeling Subsurface Flow and Contaminant Transport (Training Courses)
Second International Conference on Ground-Water Research
Seventh National Ground-Water Quality Symposium: "Developing and Implementing Innovative Means of
Dealing with Potential Sources of Ground-Water Contamination"
Conference on Characterization and Monitoring of the Vadose Zone
Conference on Surface and Borehole Geophysics in Ground-Water Investigations
\ Conference on Methods for Determining the Location of Abandoned Wells
Fourth National Symposium and Exposition on Aquifer Restoration and Ground-Water Monitoring
''This is a representative sample of ground-water-related conferences and training programs held in 1985 For additional information, contact individual laboratories
2CERI - EPA Center for Environmental Research Information, Cincinnati, OH
Centers
In addition to activities and documents produced directly
by the laboratories, ORD supports two centers that
specialize in ground-water information transfer.
The National Ground-Water Information Center (NGWIC)
in Worthington, Ohio, houses the world's largest cata-
logued and retrievable collection of ground-water litera-
ture, concentrating on hydrogeology and water-well
technology. It contains more than 10,000 volumes,
including state publications, technical reports, govern-
ment documents, maps, reference books, and related
literature, plus over 120 periodical subscriptions. The
NGWIC maintains its own computerized data base, and
has the ability to search two international retrieval sys-
tems with access to over 150 additional data bases.
The International Ground Water Modeling Center
(IGWMC) serving North, Central, and South America, is
located in Indianapolis, Indiana. The Center, supported
largely by the EPA and in part by the Holcomb Research
Institute at Butler University, operates a clearinghouse for
ground-water modeling software, organizes and conducts
short courses and seminars, and conducts a research
program on ground-water modeling. A second IGWMC
office in Delft, the Netherlands, not directly supported by
EPA, serves Europe, Asia, Africa, and Australia.
As part of its activities, the IGWMC monitors and dis-
seminates information on new developments in modeling
and related fields such as computer hardware, software
for data handling, and graphics. Its training program
stresses principles, concepts, theories, and applications
of ground-water models. In addition, the Center provides
assistance to Federal and state agencies and private
groups in organizing and conducting specially designed
training programs. The Center's publications include the
Ground-Water Modeling Newsletter, which contains infor-
mation about new publications, computer models, con-
ferences, seminars, and announcements of related
services.
32
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7. Synergism in Research:
The Stanford/Waterloo Project
Of necessity, ground-water researchers often examine
discrete subject areas (for instance, dispersion in certain
immiscible fluids), and study them on a small scale (for
instance, in a laboratory microcosm). Because ground
water is a complex subject, this is often the best way to
gain a clearer comprehension of individual processes.
However, researchers must consider whether the results
of short-term, discrete, small-scale studies will validly
translate to the long-term realities of contaminant move-
ment in ground water. The question arises: How to take
the small pieces of the puzzle and fit them into a larger,
coherent whole?
In one effort to address this question, ORD has spon-
sored the Stanford/Waterloo project, an attempt to pro-
vide new understanding of the long-term behavior of
contaminants in ground water. This project is an
extramural effort monitored by the RSKERL laboratory
and conducted jointly by Stanford University and the
University of Waterloo, Ontario, Canada. It has two com-
ponents: a large-scale study of organic contaminant
transport, and an investigation of leachate from munici-
pal sanitary landfills.
Study of Organic Contaminant Transport
The study of organic contaminant transport attempts to
provide a holistic approach to the study of ground water.
It combines many of the components of ground-water
research, such as laboratory studies and mathematical
models, and integrates them with an exceptionally large-
scale field investigation which is comparable in spatial
size to an actual ground-water contamination site.
Equally important, the study has been made over a two-
year period —a time span that reflects conditions
representative of actual ground-water flow. The study
has been a multidisciplinary effort combining the skills
and points of view of theoretical, practical, and computa-
tional scientists.
The study used a large-scale controlled field site to
determine transport characteristics of selected hazardous
contaminants in ground water, and to test the applica-
bility of theories and mathematical models to laboratory
and field findings. The project site was a section of a
Canadian sand aquifer system, whose surface dimen-
sions (10 x 100 m) are approximately the size of a foot-
ball field. The site was chosen for several reasons. Sand
aquifers are widely used as drinking water sources in the
United States (for instance, New Jersey's water supply is
largely based on sand aquifers). Therefore, the research
findings have potentially broad practical applicability.
Because the water table was quite close to the surface
for the aquifer, monitoring was made simpler. In addition,
the aquifer had already been closely studied, and had
been well characterized by hydrogeologists and
geochemists.
To study the behavior of contaminants in ground water
(particularly halogenated organic compounds selected
from EPA's priority pollutant list), scientists injected two
inorganic tracers (chloride and bromide), and five organic
solvents in a known and constant flow in water down
nine injection wells. An extremely closely spaced
monitoring network was installed so that detailed spatial
analyses of the contaminants over time could be made.
The network included 276 multilevel sampling devices
containing over 4,000 individual sampling points. More
than 18,000 samples were taken over the two-year pro-
ject period. Specific quantitative measures of the rate
and kind of solute motion and the amount of solute were
obtained.
Researchers determined that total mass was conserved
for the inorganic tracers and two of the organic solutes
(carbon tetrachloride and tetrachloroethylene), while for
three other solutes (bromoform, 1,2-dichlorobenzene, and
hexachloroethane) mass decreased in a manner suggest-
ing that degradation had occurred. The speed and path-
ways of the inorganic tracers remained nearly constant.
The organic solutes followed the tracer pathways at
reduced speeds; the rate depended on the specific solute
(Figure 15).
Sorption and degradation phenomena were investigated
in the laboratory to elucidate the solute behavior
observed in the field. The reductions in speed were
attributed to the solutes' sorptive interactions with the
aquifer solids. Another finding was that sorption
equilibrium (i.e., the state where the sorption capacity of
the aquifer solids is saturated) was achieved much more
slowly than previously believed. These findings con-
tradict prior expectations that the rate of sorption, as
well as mobility, should be constant.
In a companion effort in the laboratory, studies showed
that hexachloroethane can be degraded by microorgan-
isms under simulated ground-water conditions. This is a
promising finding, because prior studies suggested that
chlorinated compounds, particularly those that contained
several chlorine atoms (such as hexachloroethane), were
resistant to biodegradation.
This study of organic contaminant transport is a land-
mark effort in ground-water research because of a com-
bination of factors: the physical size of the project; its
33
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SYNERGISM IN RESEARCH
(m)
60
50
40
30
20
10
647 days
462 days
o-
Q-,
85 days
x
(ml
60
50
40
30
20
10
633 days
I
x
(ml
60
50
40
30
20
10
633 days
380 days
16 days
I
-10 0 10 20 30 y(m)
CHLORIDE
-10 0 10 20 y(m) -10 0 10 20 y(m)
CARBON TETRACHLORIDE TETRACHLOROETHYLENE
Figure 15. The Stanford/Waterloo Project. Location of Three Chemical Plumes at Selected Time Intervals. (The time contours
shown are depth-averaged.)
long duration; the level of detail of the monitoring and
background information-gathering; the close cooperation
among a wide variety of theoretical and practical scien-
tists, technical experts, and managers; and the synergism
among the components, (i.e., the laboratory investiga-
tions, theoretical research, mathematical modeling, and
field investigations).
Landfill Leachate Studies
In three separate studies, researchers investigated multi-
ple leachate plumes of trace organic contaminants
emanating from two municipal sanitary landfills in
Ontario, Canada. These unlined landfills, located in areas
with high water tables over sandy aquifers, are similar in
construction and hydrogeologic setting to many munici-
pal landfills in the northeastern United States. Contami-
nants investigated were largely industrial and commercial
toxicants, including chlorinated and nonchlorinated
hydrocarbons, nitrogen-containing compounds, and
chemicals produced by detergent degradation. Con-
taminants such as 1,1,1-trichloroethylene and tetra-
chlorethylene were found to be present in concentrations
of between 1 to 100 jug per liter, typical of concentra-
tions of contaminants in ground water that have caused
public concern. Sampling well sites were located up to
several hundred meters beyond the landfills.
Monitoring verified that the distribution of trace organic
contaminants was complex, and that these contaminants
followed a diverse set of pathways because of their vary-
ing densities and their immiscibility. For example,
researchers found that chlorinated solvents traveled
below the leachate plumes, and plunged toward the bot-
tom of the aquifers. Findings such as these mean that
inorganic tracers which have been used to monitor
leachate plumes through "matching" (moving along with
the plume) will not simulate the path of some organic
contaminants. Therefore, direct monitoring should be
extended to include organic contaminants. Understand-
ing the complex pathways of various organic con-
taminants is also important for refining techniques for
pumping water to clean polluted aquifers.
34
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8. Future Directions
Ground-water research is still in its formative period.
Because ground water was considered for so long to be
an ever-available, self-supplying, and self-purifying
resource, little impetus existed for scientific research. In
some respects, only a few years ago, as little was known
about organic contaminants in ground water as about the
planet Mars. In many ways the subsurface, its structure,
and its inhabitants are still alien territory. However, our
knowledge is steadily increasing. Perhaps ten times as
much is known about contaminants in ground water
today as was known ten years ago. Advances are being
made—some of them extremely promising —but technical
and scientific problems still abound.
Ground water presents a series of complex issues for
study. Our industrial society, with its plethora of chemi-
cals and by-products, combined with our diverse topogra-
phy, geohydrology, and climate, create an intricate matrix
for contamination scenarios. Physical and chemical the-
ories must be modified to apply to variable, and often
inaccessible conditions in the subsurface. The relative
newness of ground-water investigation, combined with
its complexity, point to several basic research priorities:
• Identify and study major existing and potential con-
tamination sources and agents. Efforts have been
initiated with sources such as leaking underground
storage tanks and agents such as Hepatitis A virus,
but must be pursued further.
• Invent and/or refine effective, inexpensive technol-
ogy for monitoring and sampling, source control,
and basic predictive research. Ground-water
research can only be as accurate and specific as its
tools; many advances depend largely on the
development of appropriate technology. The fiber
optic spectrometer is one step in this direction.
• Standardize data. Protection efforts (for instance,
the design of monitoring networks) and planning
decisions currently rely on data that is often incon-
sistent, making conclusions subject to error. Estab-
lishing standards for data would reduce this problem
in the future.
• Develop reliable mathematical models to predict the
movement and transformation of contaminants in
ground water.
• Conduct more field studies and studies over time
(such as the Stanford/Waterloo project, described in
Section 7) to test the validity and reliability of
models and laboratory investigations.
• Provide ground-water training for EPA, state, and
local officials. Increased training and increased
transmission of technical information are vital in this
rapidly growing field.
• Transmit information quickly. The time lag between
the verification of research findings and practical
application should be made as narrow as possible.
Future research advances will require considerable
cooperative effort at all levels: within EPA; among other
Federal, state, and local agencies; in the scientific and
industrial communities; and with scientists abroad who
are addressing similar issues. Like other environmental
problems, the contamination of ground water under-
scores a basic lesson of nature: there are no "quick
fixes." What we now know about ground water makes
its protection imperative, and a great deal more research
is needed before we can say that ground water is truly
protected.
35
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Appendix A. Principal Findings and Recommendations from the Report on the
Review of the Environmental Protection Agency's Ground-Water
Research Program, Submitted by the Ground-Water Research Review
Committee, Science Advisory Board, U.S. EPA, July 1985
The Science Advisory Board was asked by the Deputy
Administrator, Al Aim, on July 10, 1984, to review the
Agency's ground-water research program, particularly as
it supports the EPA Ground-Water Strategy (EPA, 1984),
including the transport, fate, and effects of con-
taminants, abatement and control technologies, model-
ing, monitoring and analytical methods, and quality
assurance. The Executive Committee of the Science
Advisory Board (SAB) established a Ground-Water
Research Review Committee to conduct this review,
which has now been completed.
The Environmental Protection Agency has no single
authority under which it is charged with the protection of
ground-water quality. Rather, there are a number of
different legislative authorities (with varying require-
ments) under which the Agency operates. These have all
been enacted within the last ten years, and include the
Resource Conservation and Recovery Act (RCRA), the
Comprehensive Environmental Response Compensation
and Liability Act (CERCLA), the Safe Drinking Water Act
(SDWA), the Federal Insecticide, Fungicide and Rodenti-
cide Act (FIFRA), the Toxic Substances Control Act
(TSCA), and the Clean Water Act (CWA). Much of this
fragmentation is mirrored in the research program.
EPA conducts considerable research in ground water. EPA
laboratories with major responsibilities are the Environ-
mental Monitoring Systems Laboratory-Las Vegas (EMSL-
LV), the Robert S. Kerr Environmental Research Labora-
tory (RSKERL) at Ada, Oklahoma, and the Hazardous
Waste Engineering Research Laboratory (HWERL) in Cin-
cinnati. Resources in the President's 1985 budget dedi-
cated to research in these laboratories are as follows:
Research Area
Monitoring
Prediction
Aquifer Cleanup or
Restoration
Hazardous Waste Engineering
TOTALS
Total Dollars
(in 1,000s) Man Years
1,763.0
6,307.1
853.6
9,272.0
18,195.7
9.4
31.0
6.7
46.2
93.3
Even though there are substantial resources committed
to ground-water research, there is no clearly identifiable
ground-water research "program." While the research
that is carried out is, in general, sound and responsive to
the Agency's current regulatory needs, it is inadequate to
support the Ground-Water Strategy or future regulatory
and policy needs.
The Committee's principal recommendations and the
supporting rationale are highlighted in the following
summary.
General
A. The Committee recommends that the Office of
Research and Development establish a strong
central direction for its ground-water research
program, with appropriate authority for the pro-
gram director.
Even though there is a "Ground-Water Research
Manager" in the Office of Environmental Processes and
Effects Research, the position is not officially estab-
lished, it has no authority across ORD lines, and only
deals with a part of the ground-water-related research
programs. Centralized program direction will also improve
interlaboratory coordination and the establishment of
linkages to other Federal agencies.
A major responsibility of this manager would be the
development of an integrated comprehensive ground-
water research plan. There are presently many diverse
research projects, primarily associatd with hazardous
wastes, which have a significant ground-water compo-
nent. The EPA Ground-Water Strategy is aimed specifi-
cally at the protection of ground water from any and all
sources of contamination. To support the Strategy, the
ground-water components of research programs directed
at meeting regulatory and enforcement needs must be
identified and coordinated within a broader framework. In
recognition of the rapidly advancing development in
ground-water science and technology in the private sec-
tor and in other agencies, as well as rapidly proliferating
and increasingly complex regulatory requirements, the
ground-water research plan should be amended annually
or as needed. The plan should provide for a feedback
process to Headquarters offices, regions, and states
when the planning process is complete each year, so that
they may have some idea how their needs are being met,
and their influence on the process.
B. The Committee recommends that CERCLA (Super-
fund) be amended to authorize research and that a
portion of the Superfund budget be made available
to support ground-water research.
Funding for research throughout the ground-water pro-
gram is inadequate. If one considers the enormous
expenditures projected for the Superfund program, the
benefits to be gained from having a comprehensive data
36
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APPENDIX A
base to support future remedial action decisions are sub-
stantial. In particular, projects could be designed to allow
the evaluation of the effectiveness of remedial actions
and of monitoring systems. Superfund, unlike other sta-
tutes, does not authorize research. Research at individual
sites should be authorized and encouraged. 1.5% of
annual Superfund expenditures should be made available
for ground-water research to support Superfund
activities.
C. The Committee recommends that EPA develop
and implement a plan to identify information
required for sound policy decisions arising under
the statutory programs for which it is responsible,
and that it devote substantial resources to the col-
lection and dissemination of such information.
This plan should incorporate an itemized list of major
policy decisions affecting all aspects of ground-water
protection which are now pending before the Agency or
which will arise in the foreseeable future. It should
specify in a comprehensive manner the types of informa-
tion relevant to such policy decisions, evaluate the ade-
quacy of available information in each category, and
define the necessary studies to address deficiencies.
D. The Committee recommends that EPA initiate
research on contamination sources that are not
addressed by specific Congressional mandates.
There is a critical need for research that would allow con-
clusions to be drawn concerning the relative magnitude
and importance of ground-water contamination from
sources other than "hazardous" wastes. While the
potential ground-water impact of land disposal of wastes
defined as hazardous under RCRA are being studied,
other sources may be very important contributors to
ground-water contamination. These include septic tanks,
sanitary landfills, municipal wastewater treatment opera-
tions, accidental releases, chemicals applied to the land
such as agricultural chemicals and road salt, and salt
water intrusion.
E. The Committee recommends that the Office of
Research and Development establish a formal and
thorough coordination with other Federal agen-
cies, to take maximum advantage of work being
done by others, to expand the level of expertise
available to the research program, and to prevent
unnecessary duplication.
The Committee finds that there is inadequate research
coordination among Federal agencies, even though
researchers themselves are often aware of their peers'
activities. This situation results in a lack of effective utili-
zation of results, confusion, and unnecessary duplication.
The Research Program
F. The Committee recommends that EPA accelerate
research to determine the applicability of land
treatment as a source control option.
While the reauthorization of RCRA may eliminate land
disposal of certain hazardous wastes, the land will con-
tinue to be used for the degradation and immobilization
of many wastes. A major effort should be established to
determine the land treatability of all classes of hazardous
and non-hazardous wastes.
G. The Committee finds that the funding for research
on monitoring is inadequate, and should be
increased.
Funding for monitoring research is now at about 10 per-
cent of the entire ground-water research program, and
yet monitoring is crucial to results in programs such as
RCRA and Superfund. The monitoring share of the
research funding should be increased, but not at the
expense of other components.
H. The Agency should emphasize and expedite the
development of ground-water sampling and ana-
lytical methods which have proper performance
and validation data and proper QA/QC procedures.
The Agency's current sampling and analytical methods
for ground water are often deficient in their lack of data
on accuracy and precision, proper validation, and ade-
quate QA/QC, including the lack of reliable QA samples
and standards.
I. The Committee recommends that EPA increase its
program of field evaluation of prediction tech-
niques.
While the USGS has a modest program of field investiga-
tions underway, the EPA has specific needs for field-
evaluating processes, models, and assumptions used by
its regulatory programs. To increase the confidence of the
state-of-the-art in prediction, EPA should accelerate its
field evaluation program. In addition, statistical tools
should be developed that provide a means of assessing
the heterogeneity, range, and uncertainty in basic data
and in predicted impact on ground-water contamination,
particularly where local data for deterministic model use
may be poor or nonexistent.
37
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APPENDIX A
J. The Committee recommends that EPA increase
research in the basic processes that govern the
transport and fate of contaminants in ground
water, including the necessary data bases for field
application.
Data are needed for the application of prediction tech-
niques to specific chemicals or combinations of chemi-
cals within the hydrogeologic environment. The
understanding of basic processes in ground-water trans-
port remains one of the top priority items in any fate and
transport research program.
K. The Committee recommends that EPA continue to
assess field application of available containment
techniques (i.e., caps, liners, barriers, and
hydrodynamic controls) for containment of pol-
luted ground water.
A wide variety of containment techniques, including such
things as caps, liners, walls, and hydrodynamic controls
are being utilized at disposal facilities and Superfund
sites. Controlled test data relating to their effectiveness
is lacking. A controlled study program should be
instituted at RCRA and Superfund sites, which will serve
as excellent field laboratories.
L. The Committee recommends that EPA develop
methods for remedial action in geologic regions
characterized by fractured formations or karst
topography.
Monitoring procedures and remedial activities commonly
assume that the ground-water system or aquifer is made
up of homogeneous, isotropic materials. This assumption
is frequently incorrect, rendering useless the conven-
tional techniques utilized in monitoring and remediation.
M. The Committee recommends that EPA initiate
research to identify suitable geologic environ-
ments for isolating hazardous wastes by means of
injection wells, including methodologies for
monitoring the integrity of the containing layer.
Injection wells are already receiving a significant portion
of difficult-to-treat industrial wastewater effluent. There-
fore, efforts to help choose favorable geologic environ-
ments for injection wells and to solve problems of
monitoring the integrity of the geologic containment
should be expanded.
Technology Transfer and Training
N. The Committee finds that a greatly expanded
ground-water technology transfer and training pro-
gram is a critical Agency need.
This need was expressed by virtually all of the individuals
and organizations interviewed by the Committee, and
applies both to the large in-house staff working on
ground-water-related issues without adequate experience
or training, and to state and local governments on whom
EPA ultimately depends for proper ground-water manage-
ment. This includes the transfer of information generated
by and within EPA, as well as that generated by other
Federal agencies, the states, consultants, and other
countries.
O. The Committee recommends that EPA establish an
in-house training center in ground-water science
for the technical training of EPA staff, as well as
state and local officials.
A critical shortage of trained ground-water personnel
exists within EPA and state governments. The problem is
particularly acute for EPA, since the Agency has a large
pool of undertrained professionals who are forced by cur-
rent operational requirements to make ground-water deci-
sions on a daily basis. An in-house training center could
provide training tailored to regulatory program require-
ments, which would greatly ameliorate the training pro-
gram. This training should be directed not only at
Headquarters and Regional staff, but also could assist in
improving skills of state and local personnel upon whom
EPA will depend when the Ground-Water Strategy is
implemented.
P. The Committee recommends increased technology
transfer among EPA laboratories. Regional offices,
and state regulatory agencies.
First, the Committee recommends an annual combined
presentation at each Regional office by laboratory per-
sonnel from each ground-water research facility. The
audience should include those involved in such ground-
water-related programs as Underground Injection Control
(UIC), Superfund, RCRA, Leaking Underground Storage
Tanks (LUST), and the implementation of the Ground-
Water Strategy. State and local personnel should also be
encouraged to attend. This series of presentations would
not only provide a means for updating Federal and state
field personnel on advances in ground-water research,
but would also be the basis for input to the research
laboratories. The Committee also recommends expanding
the program of making existing scientific information,
such as computerized data at the National Ground Water
Information Center (NGWIC), readily available to the
states and to EPA Regional offices.
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Appendix B. Ground-Water Research in Other Federal Agencies
Several Federal agencies sponsor research programs that
examine ground-water-related issues. The descriptions of
their research given below are not intended to be com-
prehensive, but rather to provide a general context in
which to place EPA's research programs. For more
detailed information, the reader should contact the
specific agencies mentioned.
The ground-water research of other Federal agencies is
summarized in Table 7. EPA integrates its research efforts
with these other agencies through joint projects, work
groups, committee participation, and informal informa-
tion exchange. The United States Geological Survey
(USGS) is the major Federal agency doing ground-water
research, and receives the bulk of Federal funding. Since
1981, EPA has operated under a general memorandum of
understanding (MOD) with the USGS. As a result of
EPA's Ground-Water Protection Strategy (of which the
research programs are a part), an MOU specifically on
ground water was signed in June 1985. It addresses data
collection and technical assistance as well as research
coordination.
U.S. Geological Survey
The overall research goal of the Geological Survey
(USGS) is to be able to quantitatively predict the
response of hydrologic systems to natural or man-made
stress.
Table 7. Ground-Water Research in Other Federal Agencies
RESEARCH CATEGORY
AGENCY
SOURCE
CONTROL
PREDICTION MONITORING CLEANUP
OBJECTIVE
U.S. Air Force
Develop methods for predicting the impact of
Air Force activities on ground water.
U.S. Army Corps of Engineers
Develop cost-effective ground-water pollution
control and monitoring systems; provide
environmental and health effects data on
Army-unique pollutants; develop environ-
mental management systems and data bases.
U.S. Department of Agriculture
Provide basis for evaluating effects of changes
in agricultural techniques on ground-water
quality.
U.S. Department of Energy
Provide information on mechanisms contribut-
ing to transport and long-term fate of energy-
related contaminants in ground water.
U.S. Geological Survey
Provide research to describe, assess, and
develop ground-water resources.
National Science Foundation1
Perform basic research.
U.S. Navy2
Tennessee Valley Authority
Provide data needed for assessing the sig-
nificance of potential Tennessee Valley
ground-water contamination sources and for
preventing and isolating contamination.
'Fundamental research will contribute to all areas, although it is not necessarily specifically directed toward ground-water projection
2Program just beginning to be defined.
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APPENDIX B
In FY '84, the USGS collected ground-water measure-
ments at over 35,000 observation wells and sampled
approximately 7,500 wells for subsequent water-quality
analysis. Data-collecting activities are expected to con-
tinue at approximately the same level through FY '86.
Under the Federal-state cooperative program, the USGS
conducted 570 multidisciplinary projects concerning
water quality, waste disposal and pollution, land use, and
problems related to ground-water availability. Almost half
these projects focused on ground water. Typical USGS
projects use model simulation and statistical analysis to
improve the understanding of aquifer systems within a
state and to enable managers to protect and develop
resources based on this information. Future efforts will
attempt to determine the types and extent of contamina-
tion in places with the highest priority problems accord-
ing to the EPA's Ground-Water Protection Strategy.
The USGS Water Resources Division offers technical
assistance to other Federal agency programs. For exam-
ple, it gathers hydrogeologic and geochemical informa-
tion about petitioned aquifer systems to help EPA to
decide whether the systems should be declared sole-
source aquifers.
USGS Ground-Water Research Programs
The USGS maintains four research programs on ground
water, as described below.
The Regional Aquifer Systems Analysis (RASA) Program.
This program, started in 1978, has instituted 19 studies
to investigate ground water in various hydrologic regions.
Five of these studies have been completed. Three new
studies will be started in I986 to investigate the central
Texas Aquifer, the Appalachian Valley and Piedmont
Aquifer, and the Carbonate and Glacial Aquifer of Ohio
and Indiana. Because of the complex hydrogeology of
regional aquifer systems, all RASA studies use model
simulation to synthesize ground-water flow systems and
to evaluate the impact of stresses on aquifer systems.
The Toxic Waste/Ground-Water Contamination Program.
This program improves understanding of the various
processes controlling the movement, fate, and alteration
of toxic substances in ground water. The program cur-
rently sponsors research in three areas: 1) basic hydro-
logic, physical, chemical, and biological processes-
including hydrodynamic dispersion, statistical properties
of hydraulic conductivity, multiphase flow, fractured flow,
chemical reactions, microbiological reactions, adsorption
in the subsurface, and the use of surface geophysical
methods to define the flow medium and the extent of
leachate plumes; 2) detailed field studies of ground-water
contamination at six sites: the oil spill at Bimidji, Minne-
sota; sewage treatment effluent at Cape Cod, Massachu-
setts; creosote contamination at Pensacola, Florida;
heavy metals from mining at Tar Creek, Oklahoma; and
two additional sites (to be selected) contaminated with
gasoline and chlorinated hydrocarbons; and 3) large-scale
water quality studies in six to eight areas with contrast-
ing geohydrologic and climatic characteristics, which will
document the kind, distribution, and concentration of
contaminants in ground water, and relate the origin of
this contamination to overlying land use practices.
The Nuclear Waste Hydrology Program. This program
addresses both low-level and high-level nuclear waste
issues related to ground water. For low-level wastes,
areas of study include understanding the hydrologic and
chemical principles that relate to how radionuclides
migrate in ground water, and the chemical mechanisms
that control their leaching and migration. Modeling,
sampling, and measurement techniques will also be
developed. High-level waste investigations will provide
hydrologic and geologic information to support the selec-
tion of waste repositories, and to develop criteria for their
licensure and supervision.
The National Research Program (NRP). This program is
organized into six discipline areas. Three of these areas —
ground-water hydrology, geochemistry, and water
chemistry—touch on ground-water research activity. The
primary emphasis is on understanding ground-water-
related processes and on creating numerical simulation
techniques to allow those processes to be incorporated
into predictive models.
U.S. Department of Agriculture
The U.S. Department of Agriculture Agricultural Research
Service Ground-Water Program investigates and models
the fate and transport of nutrients and pesticides in
ground water, and measures salinity in ground water as
influenced by irrigation practices. Advances have been
made in agricultural and chemical technology and soil
and water chemistry in several areas: the study of chemi-
cal and biological processes, model development and
testing, the design of management and control practices,
and the development of data bases. The goals of this
research program are to improve water management
practices, conservation tillage, and other cropping sys-
tems; to devise new chemical control technologies; and
to develop more efficient application practices for pesti-
cides and fertilizers.
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APPENDIX B
U.S. Department of Energy
The U.S. Department of Energy Subsurface Transport Pro-
gram studies the influence of chemical, physical, hydro-
logical, and biological processes on the transport and
long-term fate of energy-related contaminants such as
trace metals, organic compounds, and radionuclides. Cur-
rent studies concern the relationship of chemical
processes to the transport of energy-related organic com-
pounds. Long-term plans include a 10-year program to
develop the second generation of predictive models,
through a combination of complex computer systems,
laboratory and university consortia, and field
experiments.
U.S. Air Force
The Air Force is collaborating with the EPA to develop
methods for predicting the impact of various Air Force
activities on ground water, for example, solvent use, fire-
fighting training, waste disposal, and accidental spills. In
addition. Air Force researchers are collaborating with the
EPA to determine the extent and impact of dioxin con-
tamination resulting primarily from the use, storage, and
disposal of Agent Orange. A third collaborative area of
study is the development of methods for the restoration
of ground-water quality.
U.S. Army Corps of Engineers
The Army Corps of Engineers does research to develop
cost-effective pollution control and monitoring systems,
to provide environmental and health effects data on pol-
lutants unique to the Army, and to improve management
systems and data bases. Areas being studied include
methods and processes for containment and decontami-
nation of ground water, landfill leachate control methods,
and hazardous waste management techniques.
The Tennessee Valley Authority
The Tennessee Valley Authority (TVA) Research Program
is designed to protect and preserve the ground-water
resources of the Tennessee Valley. The program evaluates
methods for identifying recharge areas that have com-
plex geologic structures; determines the characteristics
and fates of toxic contaminants at selected problem
sites; develops methods to predict the effects of aban-
doned waste dumps and mining activities on ground
water; assesses the potential effects of power plant
wastes on ground-water quality; and implements the
ground-water protection plan in the First Tennessee-
Virginia Development District.
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