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Session 3:
Analysis and Fate
X-Ray
Fluorescence Analyzer as a Screening Tool for Lead
Remediation in Soil
Jerry Kashatus, URS
Corporation, Gaithersburg, MD
Adsorption
of RDX to Soil with Low Organic Carbon: Laboratory
Results, Field Observations, Remedial Implications
William A. Tucker,
Harding ESE, Inc., Gainsville, FL
Effect
of Aging on MassTransfer of Benzene and Naphthalene from
Crude Oils and Creosotes to Water
Subhasis Ghoshal,
McGill University, Montreal, Quebec
Subsurface
Fate and Transport of Ethanol and its Potential Impact on
BTEX Bioattenuation
Rula A. Deeb,
Malcolm Pirnie, Inc., Oakland, CA
The
Fate of Drummed Organic Solvents in a Landfill
Environmental: Implications to Remedial Action
Robert D. Mutch,
Jr., Brown and Caldwell, Mahway, NJ
Sharing
Good Data Changes How We Make Decisions
Arnold Gray, Gaea
Technologies, Cherry Hill, NJ
X-Ray
Fluorescence Analyzer as a Screening Tool for Lead
Remediation in Soil
Jerry Kashatus, C.P.G., URS
Corporation, Denise Hancsak, P.E., United States Coast
Guard, CEU Cleveland
This paper is a case study
of two sites, each with distinct geologic and
environmental histories and how an X-Ray Fluorescence
Analyzer (XRF) expedited characterization and/or
remediation while saving time and money. XRF is a field
instrument used traditionally to detect lead in paint on
walls and on structures.
The first site is in
Virginia, in the Piedmont physiographic province, and was
used as an industrial site over a 25-year period.
Lead-based paints were used on the site, in a building
having a bare earth floor. Analytical results from
preliminary screening of the soil floors reported lead
levels up to 1,800 mg/kg just below ground surface, which
exceed the screening level for lead concentration in soil
of 400 mg/kg.
The second site is a
renovated lighthouse located in the Coastal Plain
sediments of New Jersey. Lead was detected in the soil
surrounding the lighthouse at levels above the 400 mg/kg
regulatory limit. This lead was most likely introduced
into soils in the vicinity of the lighthouse during past
application of lead-based paint.
An XRF was used at both
sites to screen soils contaminated with lead. Soil samples
were subsequently collected and sent to an offsite
laboratory for confirmatory lead analysis. The laboratory
results were compared to the XRF results. There was good
correlation between the XRF field screening results and
laboratory analytical results at both sites.
Adsorption
of RDX to Soil with Low Organic Carbon: Laboratory
Results, Field Observations, Remedial Implications
William A. Tucker, Harding
ESE, Inc.
Adsorption isotherms were
determined on 16 soil types. Linear isotherms (Kd)
were observed, and statistical tests were performed to
determine the relationship between Kd and
various soil characteristics. The strongest factor was a
linear relationship to OC, as expected, but regression of
Kd to OC indicated a non-zero intercept,
suggesting that other sorbents may also be significant at
low OC (e.g., < 0.5 %). These results were used to
interpret observations of RDX in the vadose zone at Milan
Army Ammunition Plant (MAAP), TN.
MAAP exhibits widespread
soil contamination by RDX. Depth to groundwater ranges
from 40 to 80 ft. Unsaturated soils are fine grained near
the surface, sandy near the water table. RDX is
concentrated in the upper 2 ft, where concentrations in
some places exceed 1 %. Subsurface concentrations are
generally less than 50 mg/kg. Extensive soil, soil
moisture, groundwater sampling, and soil physical testing
was interpreted using simple models. The distribution of
RDX is consistent with the following conceptual model:
- Water containing RDX was
discharged to the land surface (prior to 1983);
- Crystalline RDX remains
in surface soil (remedial activities are ongoing);
- Infiltrating rainwater
leaches RDX from surface soils and percolates at
concentrations approaching solubility;
- This leachate carried
RDX through the deeper vadose zone, leading to
concentrations near the chemical saturation capacity
through the full unsaturated zone.
Field observations were
consistent with the adsorption studies. Deep soils that
have become contaminated by the movement of contaminated
leachate may continue to adversely affect groundwater
quality for decades.
Effect
of Aging on Mass Transfer of Benzene and Naphthalene from
Crude Oils and Creosotes to Water
Catherine Pasion,
M. Eng, Mohammed Alshafie and Subhasis Ghoshal, McGill
University, Montreal, Canada
At contaminated sites, nonaqueous phase liquids (NAPLs)
such as crude oil, creosote and coal tar, often remain in
contact with ground or surface water for long periods of
time before or during any attempted remediation. During
that time solutes such as aromatic or polycyclic aromatic
hydrocarbon compounds are continuously released from the
NAPL into aqueous phase causing ground and/or surface
water contamination. Extended contact of oil and aqueous
phases (aging) results in an unique interfacial
phenomenon: the formation of semi-rigid films at the NAPL-water
interface. The objective of the research is to investigate
whether aging of NAPL-water interfaces and the formation
of interfacial films retard dissolution of two target
solutes, benzene and naphthalene, from samples of crude
oil and creosote.
Mass transfer experiments were conducted in gently
stirred flow-through reactors where the NAPL and the
aqueous phases were kept segregated. The aqueous
concentration in the reactor effluent was determined in
samples collected at different time points. The
equilibrium partitioning coefficients and aqueous
concentration data were fitted to a three-film mass
transfer model describing the transport of a target solute
from the oil phase to the aqueous phase in the presence of
an interfacial resistance. An area-independent mass
transfer coefficient which defines the rate of mass
transfer of a target solute within a given NAPL-interfacial
film-water system, was calculated by fitting the
three-film model to reactor aqueous concentration data
using non-linear regression techniques. It has bee found
that with aging the mass transfer rate coefficients of the
target solutes from the NAPLs to water was reduced by
factors ranging from 2 to 66 with up to 35 days of aging,
indicating significant reductions of rates of mass
transfer over time. This has important implications on
potential rates of biodegradation of the solutes, and for
rates of clean-up of NAPL-contaminated sites in general.
Subsurface
Fate and Transport of Ethanol and its Potential Impact on
BTEX Bioattenuation
Rula Deeb, Malcolm Pirnie, Lisa Alvarez-Cohen,UC
Berkeley and Michael Kavanaugh, Malcolm Pirnie
Recent legislation in California called for the removal
of the fuel oxygenate methyl-tert butyl ether (MTBE)
from gasoline by the end of 2002. In order to comply with
Federal Clean Air Act requirements of attainment of carbon
monoxide and ozone standards, California is considering
the use of ethanol as a replacement for MTBE in gasoline.
The objectives of this study are as follows:
- The effects of key physical and chemical properties
of ethanol and MTBE on their fate and transport in the
environment will be evaluated. Several modeling
analyses will be utilized to illustrate the
differences in behavior between ethanol and MTBE
following accidental releases of oxygenate-blended
gasoline. One modeling exercise will entail the
development of a single release scenario into two
different hydrogeologic subsurface environments, the
first involving a sandy homogenous aquifer with
rapidly moving groundwater, and the second involving a
loamy aquifer with slow groundwater flow and a high
organic carbon content. The second modeling exercise
will entail modeling the fate of ethanol and MTBE in
surface water following gasoline releases from
recreational watercrafts.
- The impact of ethanol on the biodegradation rates of
the major aromatic components in gasoline, BTEX
compounds (benzene, toluene, ethylbenzene and xylene),
will be evaluated in laboratory studies using one
mixed culture indigenous to a gasoline-contaminated
aquifer, and two pure cultures designated RR1 and PM1.
The mixed culture and RR1 degrade ethanol and BTEX,
while PM1 degrades ethanol, BTEX and MTBE. Substrate
interactions will be evaluated in mixtures of BTEX and
ethanol in order to quantify the impact of ethanol on
BTEX biodegradation rates. Preliminary studies reveal
that when RR1 is grown on toluene and exposed to
mixtures of toluene and ethanol, there is an observed
lag in the biodegradation of ethanol. However, when
RR1 is grown on non-aromatic carbon sources such as
pyruvate and tryptic soy broth, the biodegradation of
ethanol and toluene takes place simultaneously with
ethanol degrading at a faster rate than any of the
BTEX compounds. The biodegradation of BTEX and MTBE by
PM1 was enhanced in the presence of ethanol which has
been shown to be an effective growth substrate for
this organism. Further studies will focus on
evaluating the impact of ethanol on BTEX degradation
rates in mixtures in soil column studies. Laboratory
observed rates will then be used in conjunction with
groundwater models to predict the effects of ethanol
on BTEX plumes lengths in subsurface environments.
The
Fate of Drummed Organic Solvents in a Landfill
Environment: Implications to Remedial Action
Robert D. Mutch, Jr., P.Hg.,
P.E., and Robert D. Norris, Ph.D., Brown and Caldwell
The seemingly obscure
question of the fate of drummed organic solvents in a
landfill has, in recent years, become a question of great
practical and monetary importance. Many of the nation’s
Superfund sites are large, co-disposal landfills. Often,
the industrial waste deposited in these landfills was
contained in standard 55-gallon drums. A basic question
has arisen that is tied directly to the fate of the
drummed waste: Is the impact of a landfill likely to
worsen in the future as drums begin to deteriorate and
release their contents, or is the impact more likely to
lessen over time because the peak impact of drummed wastes
on leachate quality has already passed? Consequently, is
there any merit to attempting to excavate drummed wastes
from the landfill matrix? This paper examines the loss in
drum integrity within a landfill environment due to both
mechanical disruption during landfilling and subsequent
corrosion within the landfill. Drum corrosion rates are
derived from the benchmark studies of the U.S. Nuclear
Regulatory Commission and the National Bureau of
Standards. This data is then compared to experiential
evidence derived from the many documented cases of drum
excavations from landfills. Recent studies have also
demonstrated that landfills produce uniquely favorable
conditions for biodegradation of typically recalcitrant
chlorinated solvents. The elevated dissolved organic
content found within and downgradient of landfills leads
to anaerobic conditions and low redox potential, creating
conditions which degrade chlorinated solvents at unusually
high rates. The implications of these findings to remedial
action are then examined.
Sharing
Good Data Changes How We Make Decisions
Dr. Arnold Gray, Gaea Technologies, Mitch Beard,
EarthSoft, Inc.
The ability to share data among the many projects in
adjoining areas, within watersheds and across media is
changing how we can make environmental decisions. Until
now, environmental analysts and regulators have been
unable to share data from project to project. Managing the
data for a single project was such a difficult and time
consuming task that it was all a Project Manager could do
to just get the basics from the data. Project Managers who
had projects that were side by side would not be able to
share data, and even if the water level dropped in Project
A when the pumps were turned on in adjacent Project . It
was simply too difficult to model the two systems as one.
Expand the problem to examining the data across a
watershed or across media, and the task became impossible.
Selecting an optimal remediation strategy for
environmental sites is never a straightforward, easy
process. Successful management and decision analysis
requires not only the availability of spatial, chemical,
and geologic data, but also an integrated environmental
quality information system which allows a project manager
to utilize and analyze the data. Systems are being
implemented by the Colorado Department of Public Health
& Environment (CDPHE), the New Jersey Department of
Environmental Protection, (NJDEP), the Delaware NREC (DNREC)
and many others to aid in achieving these data management
and analysis objectives. Data Management systems are being
tightly integrated with industry-standard visualization
and analysis tools resulting in an environmental
management system that allows the user to easily
investigate "What If...?" scenarios. The result
is enabling CDPHE, NJDEP, and DNREC to conduct a more
comprehensive and effective evaluation of environmental
impacts, migration pathways, fate and transport
mechanisms, appropriate remediation methods, effects of
remediation, and compliance. Examples illustrate how these
state organizations are implementing systems and what
benefits have been derived therefrom.
Electronic data delivery programs are key to
implementing electronic data management programs. The two
inputs can be broken into Field, or GIS data. Field data
is derived from observations and field tests from geologic
activities, hydrologic field tests, and general field
activities. Analytical data is generated in the laboratory
and includes tests, results, and QA/QC documentation from
chemical analyses. Of the two, the Analytical data
typically makes up 80% or more of the site data over time.
Both inputs can be more automated. EDD Certification
Centers, which can electronically check in and process
deliverables from authorized state lab and consultant
sources, are being established. Other tools are used to
collect field data and ensure they are correct and
consistent.
GIS is used to encapsulate the data management system,
for intuitive ease of use interfaces to the typical tools
used by groundwater professionals, such as DoD’s
Groundwater Modeling System, EVS, gINT, Rockworks, CARStat,
and many other tools. With GIS, project managers and other
non-technical staff are able to perform simple queries and
obtain reports and graphs.
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