United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5102G)
EPA542-N-01-004
November 2001
Issue No. 43
"EPA TECH TRENDS
CONTENTS
Subsurface Soil Analysis
Using an In Situ Video
Imaging System page 1
Advanced Tensiometers
for Vadose Zone
Monitoring page 2
New Compound
Identification
Technique Uses High
Resolution MS page 3
The Applied Technologies
Newsletter for Superfund
Removals & Remedial
Actions & RCRA Corrective
Action
ABOUT THIS ISSUE
This issue highlights innovative
technologies, including remote
sensing and advanced analytical
techniques, for site
characterization involving
contaminated soil, sediments, and
ground water.
Subsurface Soil
Analysis Using an In
Situ Video Imaging
System
by Stephen H. Lieberman, Space
and Naval Warfare Systems
Center/San Diego
A novel system has been developed by the
Space and Naval Warfare Systems Center/
SanDiego (SSC SanDiego) to obtain
detailed information about subsurface soil
characteristics on very small spatial scales.
Known as GeoVIS, this system uses a
miniature charge-coupled device (CCD)
color video camera coupled with magnifica-
tion and focusing lens systems integrated
into a cone penetrometer probe. The
system is designed to characterize soil
properties involved in estimating subsur-
face water flow and contaminant transport,
and to characterize complex contaminants
such as non-aqueous phase liquid (NAPL).
From inside the probe (Figure 1), the small
(5-centimeter outside diameter) GeoVIS
device uses illumination provided by white
light-emitting diodes (LEDs) contained
within the probe. The surrounding soil
environment is imaged through a flush-
mounted, 6.35 millimeter-wide sapphire
window on the side of the probe. Video
signals from the camera are returned to the
surface over a 100 foot-long video cable,
where they can be viewed in real time on a
video monitor, documented on a video
recorder, and digitized if desired. The
standard GeoVIS optics system provides a
viewing field of approximately 2 by 3
millimeters, and a magnification factor of 100
when viewed on a standard 13-inch monitor.
Laboratory testing has shown that this lens
system can distinguish particles ranging in
size from 1 millimeterto 10 micrometers.
Over the past four years, GeoVIS has been
used several times in the area of San
Francisco Bay, CA, to characterize NAPL
contaminants as part of remedial planning
at the former Naval Air Station in Alameda.
As a result of aircraft reworking operations
occurring at the facility between 1942 and
1997, high levels of fuel hydrocarbons and
chlorinated solvents remained in the
saturated zone. In particular, maximum
concentrations reaching 3,000 mg/kgfor
trichloroethy lene and 640 mg/kg for 1,1,1 -
trichloroethane were identified.
Local geology at the air station comprises
primarily fill composed of sand and silty
sand overlaying a bay mud, with a depth to
ground water ranging from 8 to 10 feet.
Direct push methods were used to deploy
the camera-equipped penetrometer probe to
a depth of approximately 20 feet. A series
of 22 pushes was made over a period of 2.5
days to delineate the NAPL zone. Through
continuous profiling, a data log on the
location of immiscible, separate-phase
product was obtained. Resulting data were
[continued on page 2]
Figure 1: Internal View of Probe
Containing GeoVIS Device
R«1r c Iwrti« yt LJ fro
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[continued from page 1]
used to optimize placement of injection and
recovery wells for a steam-enhanced
contaminant extraction system, and
subsequently to verify the extraction
system's effectiveness.
This relatively simple, in situ soil charac-
terization technique provides significant
advantages over conventional methods
involving costly and time-consuming
sample collection, offsite laboratory
analysis, and variable data extrapolation.
Most significantly, GeoVIS provides the
small-scale tools needed to identify thin
layers of highly permeable material that
provide a potential pathway for contaminant
transport and which could be missed easily
through conventional techniques. Equally
important, it provides a direct means for
locating contamination source zones that
have been very difficult to localize using
conventional sampling approaches.
Integration of the camera system generally
extends the capability of a standard cone
penetrometer, which is limited to detecting
stratigraphically different and thick soil
layers, and can improve the quantification of
other optical-based, in situ sensor systems
(such as laser-induced fluorescence) used in
field screening for petroleum products.
Current SSC efforts focus on the develop-
ment of smaller-diameter camera probes for
deployment via light-weight push vehicles,
and automated image processing algorithms
used for extracting quantitative information
(such as soil porosity and percent fuel
saturation) from the images. For more
information, contact Stephen H. Lieberman
(SSC SanDiego)at619-553-2778ore-mail
lieberma@spawar.navy.mil.
Advanced
Tensiometers for
Vadose Zone
Monitoring
by John B. Jones, U.S. Department
of Energy/Nevada Operations
Office
The Idaho National Engineering and
Environmental Laboratory (INEEL) has
developed an advanced tensiometer (AT)
for measuring the potential energy status of
water in soil and porous rock. For risk
assessment at hazardous waste sites, the
type of data obtained through AT measure-
ments is important in development of
conceptual models and water/contaminant
transport models. ATs have significant
applications in preliminary site assessments
when deployed with other data collection
instruments used to measure water content,
contaminant concentration, and tempera-
ture. Together, these tools provide a
comprehensive vadose zone monitoring
system.
The AT design is a simple, low-cost, and
low-maintenance tool, with no moving parts
and a pressure transducer that is serviceable
from ground surface. The AT operates on
the same physical principle as conventional
tensiometers to measure how tightly water is
held by soil and rock. It contains: (l)a
permanently installed porous cup with a
water reservoir and guide tube, and (2) a
removable pressure transducer (Figure 2). In
the fixed-position version, the device is
deployed by lowering it into a borehole and
bringing the porous cup into good hydraulic
contact with the subsurface soil by
backfilling. In the portable version, only the
weight of the device is used to position the
cup. Water in the reservoir then moves
through the porous cup until the pressure
inside the reservoir equilibrates with the soil
moisture pressure in the surrounding soil or
rock. The pressure transducer measures the
partial vacuum, and a data logger at the
surface records the
measurement.
Researchers have
found that the AT is
an effective monitor-
ing instrument when
soil water potential is
in the range of 0 to-
800 centimeters of
water pressure, which
is the energy status
range with the highest
hydraulic activity and
greatest potential for
rapid water movement.
These conditions
have been found in
most deep vadose
zones, except those in
areas with very low
precipitation (less
than 6 inches per
year).
Conventional tensiometers, with pressure
gauges located at ground surface, have a
practical depth limitation and are affected
adversely by barometric pressure and
ambient temperature changes. To date, the
AT has enabled soil water potential mea-
surements to be taken at depths reaching
approximately 150 meters. In contrast,
conventional tensiometers are useful at
depths of less than 7 meters in most soils
and only 3 meters in arid soils. In addition,
the AT features a short water column that is
isolated from diurnal temperature changes
and thus able to stabilize readings.
Since 1997, when initial field tests were
conducted at INEEL, the AT has been
employed at most majorU.S. Department of
Energy (DOE) facilities to obtain data
concerning water movement and subsurface
hazardous material. At the Hanford Site near
Richland, WA, sixATs ina7.6 meter-deep
lysimeter have been used steadily for the
past two years to monitor soil and water
pressures in sediments. The AT has
demonstrated the ability to continuously
monitor soil moisture potential in the vadose
zone, and to provide (for the first time)
nearly continuous documentation of pulses
of water moving deep within soil at the
Hanford Site.
DOE anticipates that the soil moisture
potential data provided by ATs also will be
[continued on page 3]
Figure 2: Advanced Tensiometer
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[continued from page 2]
useful in understanding the mechanisms of
water movement in the vadose zone and for
optimal long-term monitoring and steward-
ship programs. This project is sponsored
by DOE's Office of Environmental Manage-
ment/Office of Science and Technology
through its Characterization, Monitoring,
and Sensor Technology Crosscutting
Program.
Detailed technical information on the AT is
available from Joel Hubbell (TNEEL) at 208-
526-1747 orjmh@inel.gov, or James B.
(Buck) Sisson(INEEL) at 208-526-1118 ore-
mail jys@inel.gov. For additional project
information, contact JohnB. Jones (U. S.
DOE/Nevada Operations Office) at 702-295-
0532 ore-mailjonesjb@nv.doe.gov. More
information, including innovative
technology summary reports, also is
available on the Office of Environmental
Management's web site, www.em.doe.gov.
New Compound
Identification
Technique Uses High
Resolution MS
by Andrew H. Grange, Ph.D., U.S.
EPA/Office of Research &
Development/National Exposure
Research Laboratory
Compounds on the U.S. Environmental
Protection Agency's (EPA's) priority
pollutant lists represent only a small fraction
of the toxic compounds that might be found
at hazardous waste sites, yet established
analytical methods may not be capable of
identifying and reporting many of the other
compounds. Unidentified compounds may
produce errors in the analytical results for
known pollutants, and may complicate the
interpretation of project data used to assess
compliance or perform risk assessments.
Currently, gas chromatography/low
resolution mass spectrometry (GC/LRMS) is
used to analyze many of the compounds
listed in EPA's regulatory appendices.
Coelution of multiple components, which
can degrade an analytical instrument's
ability to identify and quantitate analytes, is
common when a sample contains dozens of
Updates on EPA Site Characterization Initiatives
The U.S. EPA's Technology Innovation Office (TIO) offers extensive online support to
waste remediation stakeholders for characterization and monitoring of sites (www.clu-
in.org/charl.cfm). The most recent additions to this continuously updated area are:
A collection of topical papers on environmental data quality
Issue papers on topics such as management of uncertainty in environmental
decisions, the triad approach to improving cost-effectiveness of site cleanup, and
EPA's methods compendium Test Methods for Evaluating Solid Waste, Physical
Chemical Methods (SW-846), and
New publications on characterization and monitoring, and related electronic
information links.
Through the Measurement and Monitoring Technologies for the 21st Century initiative,
EPA's Office of Solid Waste and Emergency Response is identifying and deploying
promising measurement and monitoring technologies (see www.clu-in.org/21m2). Recent
projects under this effort, known as 21M2, include:
Onsite testing of the PneuLog™ in-well instrumentation used to measure air
permeability and contamination production, and
The latest quarterly update of citations and abstracts concerning relevant
technology literature.
TIO also has been working with WPI over the past two years to improve communica-
tions among sensor developers, vendors, and users inside and outside of the
environmental arena. As the primary product of this collaboration, the Sensor Technol-
ogy Information Exchange (SenTIX) provides an online forum (www.sentix.org) for
discussions on technology needs, upcoming events, news topics, other information
sources, and development opportunities offered by federal agencies such as the EPA,
Department of Defense, and Department of Energy. In addition, the searchable SenTIX
database offers key information profiles submitted by developers and vendors of
technologies currently available to users.
compounds. The Environmental Sciences
Division of the National Exposure Research
Laboratory (NERL) in Las Vegas, NX has
developed a new analytical technique based
on high resolution mass spectrometry
(HRMS). This technique, ion composition
elucidation (ICE), is used to determine the
correct elemental composition for com-
pounds containing carbon (C), hydrogen
(H), nitrogen (N), oxygen (O), phosphorous
(P), or sulfur (S) atoms. In addition to
offering more definitive GC/MS analysis of
complex samples, ICE provides users with
the capability to "fingerprint" waste
composition.
For example, the chromatogram for an extract
of a black, viscous sample from a Superfund
site in West Virginia contained several
irregular and broadened peaks due to poor
resolution of individual peaks. Credible
library matches were not found for most of
the mass spectra from the compounds
producing these peaks. As a result, the
identity and quantitation of these peaks
using traditional techniques would be
highly speculative.
The ICE technique was used to identify
these compounds, the majority of which
contained one or two N and S atoms. Mass
spectra presence of a fragment ion that is
characteristic of alkylbenzothiazoles
(C ELNS) indicated that most compounds
belonged to a common family. The presence
of benzothiazoles, which are used in the
rubber and dye processing industries,
helped to confirm that the waste found at
this site had been dumped from a nearby
dye manufacturing plant. If additional
evidence had been necessary to support
legal proceedings, ICE analysis of still-
bottom residue from the dye plant could
have been used with a high degree of
certainty to identify the plant as the waste
source.
ICE also was integral to "chemical detective
work" for the Reich Farms Superfund site
near Toms River, NJ. Laboratories using
conventional LRMS and HRMS techniques
were unable to identify several compounds
found in a municipal well located one mile
from the site. ICE analysis, however,
[continued on page 4]
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[continued from page 3]
determined the elemental composition of a
molecular ion (C14H14N) and 10 fragment
ions in the well sample s mass spectrum
(Figure 3a). Chemical literature was
searched for possible compounds with
spectra corresponding to the patterns
produced through ICE analysis. The
literature suggested that plastics
manufacturing based on a 1 :2 sytrene:
acrylonitrile industrial polymerization
process could produce these compounds as
byproducts.
To evaluate the potential links, a corporation
using a similar polymerization process
provided a sample for use in comparison to
the Reich Farms site sample. The corporate
sample yielded a mass spectrum very similar
to that of the well water sample at the same
retention time (RT) of 17.47-17.48 minutes
(Figure 3b). In addition, the 16.7- to 17.9-
minute portion of the
mass/charge ratio (m/
z) 129ionchromato-
gram corresponded to
the largest peak in the
mass spectra for both
the corporate sample
polymerization process and the com-
pounds present in the well water, EPA's
Region 2 office pursued toxicology
studies on these compounds.
For more information on the technical
details of ICE and its application to these
and other analytical problems, visit http:/
/www.epa.gov/esd/chemistry/ecb-
posters2.htm, or contact Dr. Andrew
Grange (U.S. EPA/NERL) at702-798-2137
ore-mail grange.andrew@epa.gov.
and the well water
extract (Figure 3c).
These findings
helped to determine
that three of the five
compounds present
in the well water
extract also were
present in the
corporate sample. As
a result of the high
certainty of a match
between the industrial
Figure 3: Mass Spectra Comparison for Reich Farms
Superfund Site
(a) mass spectrum for well water extract isomer (RT of 17.48)
(b) mass spectrum for corporate sample isomer (RT of 17.47)
(c) m/z 129 ion chromatograms for well water extract and sample
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EPA542-N-01-004
November 2001
Issue No. 43
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