5
\
Ti
 o
                         /A newsletter about soil,  sediment,  and ground-water characterization and remediation technologies
                         Issue 19

This issue o/Technology News and Trends looks back to find lessons learned from projects described in
earlier issues of the newsletter.
                                                                                                      July 2005
           Chitin Emplaced Using Hydraulic Fracturing Enhances
                        Bioremediation of Ground Water
Following a successful pilot-scale field test in 2002.
full-scale application of "biofracing" was conducted
over a 26-month period in 2003-2005 to remove
chlorinated solvents from ground water at the Distler
Brickyard Superfund site near West Point, KY (For
information on site conditions and details concerning
the pilot, see the January 2003 issue of Technology
News and Trends.) Anatural hiopolymer derived from
shrimp and crab shells, chitin was injected into a tight
aquifer using hydraulic fracturing to provide a source
of volatile fatty acids (VFAs) that served as electron
donors for anaerobic reductive dechlorination (ARD).
The frill-scale results continued to show that the
technology effectively delivered chitin within the site's
low-permeability  subsurface, generated highly
reducing geochemical conditions, and significantly
stimulated natural biodegradation of chloroethenes.

The full-scale test application was designed to further
evaluate the effectiveness and longevity  of chitin-
stimulated biodegradation in the field and to
concurrently evaluate the perfomiance of various
grades of chitin under laboratory conditions. Using
techniques similar to those of the pilot test, a larger
network of 33 hydraulic fractures was initiated from 10
direct push holes within an expanded (0.4-acre)
treatment area. Approximately 4,800 pounds of chitin
were mixed with sand in a guar slurry and in] ected into
the aquifer, creating hydraulic fractures that extend
15-20 feet through the area's fine-textured sediment.

Monitoring focused on VFA concentrations, redox
indicators, and concentrations of trichloroethene
(TCE) and its degradation products in ground water.
Visual examination of soil cores helped to document
the fracture network geometry and evaluate changes
in chitin over time.
                             Soil cores collected one week after chitin emplacement
                             showed that the location of chitin- and sand-filled
                             fractures highly corresponded to locations inferred
                             by inverse modeling of data obtained from a network
                             of tiltmeters. Visual examination of a second set of core
                             samples collected eight months later showed that chitin
                             degradation was accompanied by development of
                             strongly reducing conditions.  Sediment near the
                             fractures tod changed in color from tan to dark gray,
                             and the presence of a black precipitate (likely a sulfide
                             mineral) was observed in the fractures. These changes
                             suggest that the strongly reducing conditions needed
                             for ARD ID occur were generated near chitin-filled
                             fractures.

                             Ten rounds  of ground-water monitoring data
                             demonstrated that VFA production began almost
                             immediately after chitin emplacement and continued
                             over the following year (Figure 1). Total VFA
                             concentrations one week after chitin emplacement
                             ranged from 8.4 to 5,020 mg/L, with a median
                             concentration of 109 mg/L.

                             VFA production was accompanied by development
                             of strongly reducing conditions, as indicated by lower
                             sulfate  concentrations and higher  methane
                             concentrations.  Production  of  the  highest
                             concentration of methane (25 mg/L) occurred
                             approximately eight months after the chitin was
                             emplaced. when maximum c-is-dichloroethene (DCE)
                             concentrations also were observed Overall, increased
                             concentrations of ds-\2 DCE and ethene (Figure 2)
                             show that biodegradation of TCE was significantly
                             stimulated by chitin emplacement. Concentrations of
                             ethane, as a final TCE  degradation product, peaked
                             nearly four months after chitin placement and

                                                    [continued on page 2]
                                                                                        Contents
Chitin Emplaced Using
Hydraulic Fracturing
Enhances Bioremediation
of Ground Water          pagel

Continued Triad
Approach for NAPL
Removal Expedites Fort
Lewis Cleanup           page 2

Field Tests Show
Enhanced
Bioremediation
following Cyclodextrin
Flushing                 page 4

"Supermulch"
Amendment Expedites
Revegetation at Mining
Sites                     page 5
     CLU-IN Resources
 The Technology Innovation
 News Survey (TINS) contains
 market and commercialization
 information; reports on demon-
 strations, feasibility studies,
 and research; and other
 technology development news
 of interest to the hazardous
 waste community. To browse
 the TINS archives or subscribe
 to bimonthly updates, visit
 http://clu-in.org/products/tins/.
                                                                                                             Recy cled/Recy cl able
                                                                                                             Printed with Soy/Canola Ink or paper that
                                                                                                             contains at least 50% recycted fiber

-------
  Figure 1. Representative data from one of
  17 monitoring wells showed that injection
  ofchitin in Distler Brickyard ground
  water produced a range ofVFAs that were
  available to serve as electron donors for
  enhanced bioremediation.
[continued from page 1]
remained  elevated  to  various degrees
throughout the project period.

Concurrent laboratory column studies were
conducted at Pennsylvania State University to
compare VTA production,  chloroethene
degradation, and chitin longevity for three
grades of chitin (SC-20, SC-40, and SC-80).
While the most refined grade of chitin (SC-80)
demonstrated superior performance in terms of
VFA production and chloroethene degradation,
the least refined grade (SC-20) performed nearly
as well. The intermediate refined grade (SC-40)
performed slightly lower. Based on these results
and an estimated factor of 2.5 cost differential
                                                 500
                                           400-
                                       S  300-
                                       c
                                       I  2oo^
                                       CD
                                       o
                                       c
                                       o
                                       O
100-
                                                 chitin
                                                 emplacement
                                                           v
                                                -+- acetate
                                                -+- propionate
                                                -*- butyrate
                                                 °  valerate
                                                 v  hexanoate

                                                         AugOS     Dec 03      Apr 04     Aug 04      Dec 04
                                    between the SC-20 and SC-80, researchers
                                    recommend the use of SC-20 in  future
                                    applications.

                                    Full-scale biofracing at this site was estimated to
                                    cost $500,000, which was provided by the
                                    National Science  Foundation under  an
                                    innovative technology grant for small businesses.
                                    It is estimated that chitin accounted for only 2.5%
  c
  o
  '•*-•
  CD
  -t—»
  C
  CD
  O
  C
  o
  O
     20
15-
10
           chitin
           emplacement
                                                    TCE
                                                    c/s-DCE
                                                    frans-DCE
                                                    vinyl chloride
                                                    ethene
     Apr 03      AugOS     Dec 03      Apr 04     Aug 04     Dec 04
                                  of the total project cost. Other agency support
                                  was provided by the U. S. EPARegion 4, which
                                  provided analytical services. The State of
                                  Kentucky, now holding lead responsibility for
                                  cleanup at the Distler Brickyard, anticipates that
                                  ground-water monitoring will continue for
                                  several years until cleanup goals are met.

                                  Contributed by Ken Logsdon,  Kentucky
                                  Department for Environnental Protection
                                  (502-564-6716 or
                                  kenneth.logsdoniSky.gov), Femi Alrindele,
                                  U.S. EPA Region 4 (404-562-8809 or
                                  akindele.femi&epa.gov), and Bob Stair,
                                  North Wind, Inc. (208-557-7878 or
                                  bstarnS'nortlnvind-inc.com)
                                                                          Figure 2. TCE breakdown was observed
                                                                          consistently over an 18-month period
                                                                          following chitin emplacement at the
                                                                          Distler Briclcvard.
                 Continued Triad Approach for NAPL Removal Expedites Fort Lewis Cleanup
Aggressive treatment of a nonaqueous-phase
liquid (NAPT) source area at the Fort Tewis
Togistics Center near Tacorna, WA,  was
undertaken last year following use of a Triad
approach for characterizing contaminant migr-
ation in the area's dual aquifer system In 2002, the
Fort Tewis Public Works and U. S. Army Corps of
Engineers (USAGE) had completed  site
characterization   involving  a   dynamic
investigation approach, systematic planning, and
                                   real-time data collection (described in the July 2004
                                   issue of Tedmology News and Trends). They then
                                   installed and operated an in-situ electrical resistance
                                   heating (ERH) system to sequentially treat three
                                   NAPT source areas of the logistics center's "East
                                   Gate Disposal Yard"

                                   The Triad approach was continued during the
                                   remediation stage to maximize removal of NAPT
                                   containing TCE and associated volatile organic
                                  compounds (VOCs) from soil and ground water
                                  at the first of die three source areas. Sequential
                                  treatment will allow lessons learned from one
                                  source area to be applied to the next through an
                                  adaptive site management approach. In the first
                                  treatment area, anonsite gas chromatograph/mass
                                  spectrometer (GC/MS) and other field-based
                                  technologies such as vibrating-wire transducers
                                  were used during ERH operations. Such onsite
                                                     [continued on page 3]

-------
[continued from page 2]
methods facilitate a dynamic  strategy for
measuring contaminant recovery rates and mass,
ensuring hydraulic containment goals are met,
modifying the treatment system as needed, and
optimizing the treatment system's efficiency.

In the first treatment area, heat was applied across
a 25,500-ft2 zone using 106 electrodes installed at
depths extending 39 feet below grade. Each
electrode contained a co-located multiphase
extraction well that was plumbedto otherelectrode
wells, resulting in six separate liquid and vapor
recovery regions. The system's original operational
requirements included a constant temperature of
100°C in the saturated zone, 90°C  in the vadose
zone soil, and sustained temperatures at these
levels for 60 days. Temperatures during system
operations  were  monitored   with  224
thermocouples.

During active treatment, the onsite GC/MS
produced water and air data within 24 hours of
sample collection and the data were posted to an
online system accessible by all project staff. A
total of 870 air samples and 858 water samples
were analyzed Offsite laboratories  analyzed split
samples and selected primary samples, including
58 air samples and 46 water samples.

Monitoring indicated that the goal of sustaining a
toiling temperature throughout the entire saturated
zone for 60 days  was unnecessary due to
diminishing return of chlorinated  solvent mass
recovery The conceptual site model consequently
was refined to reflect a tetter understanding of
contaminant distribution.  After three months of
ERH operation, the remediation  strategy was
modified to focus onmaintaining 100°Cinsmaller
areas where evidence of NAPL was noted during
pre-remediation sampling and system installation

The presence ofNAPL had been identified earlier
through use of photoionization and ultraviolet
methods, sheen tests, and specialized soil test
kits. This information was used  during ERH
operations alongside wellhead-specific vapor data
  Figure 3. Distinct changes in chlorinated
  VOC concentrations in ground water
  began  occurring 2-3 months after ERH
  startup at the East Gate Disposal Yard.
to determine whichmulti-phase extraction wells were
producing the largest mass of contaminant and to
direct electrical power toward those areas.

Approximately 95% of the thermocouples reached
the TCE boiling point (77-89=C) below the ground-
water table, and 86% reached Hie project's target
temperatures. Failure  to achieve the desired
temperatures at 31 of the thermocouples was
attributed to an unexpected  presence of distinct,
highly permeable paleochannels at depths of 16-21
feet, which introduced steady streams of cold water.
Thermocouples that reached the TCE boiling point
were maintained an average of 97 days. Those that
reached project target temperatures were maintained
an average of 70 days.

Temperature data also were used to detemrine the
point of system shutdown, which occurred after
eight months  of operation. At that  point,
temperatures in the NAPL  hot spots had been
maintained above the toiling point of TCE in water
for an average of 97 days. Subsurface temperatures
at 193 of the 224 thermocouples had reached 9QPC
in the vadose zone and 100°C in the saturated zone,
and subsurface VOC concentrations had decreased
more than 90%.

Ground-water quality data from wells inside, outside,
and below the treatment area have not  indicated
contaminant rebound within the treatment area
following shutdown of the ERH system  Similarly,
contaminant migration beyond the treatment area
after shutdown has not been observed.

Use of ERH resulted in a  total mass removal
(including vapors, dissolved-phase liquid, and
NAPL) of 2,576 kg of TCE, 405 kg of DCE, and
40,171 kg of total petroleum hydrocarbons. Vapor
data indicated that recovery of vapor-phase TCE
peaked approximately four months after system
start-up. At the same time, ground-water data
showed that TCE concentrations peaked as
NAPL transitioned to the dissolved phase. TCE
concentrations dropped over the following four
months to levels below starting concentrations
(averaging 383  |Jg/L). These estimates do not
include degradation occuring in-situ during
treatment.

Data from nine ground-water monitoring wells
showed significant reductions in chlorinated VOC
concentrations following ERH treatment (Figure
3). The highest ground-water concentration of
TCE priorto treatment was 1,500 |lg/L. Thoughit
increased to a maximum of 950,000 |Jg/L during
heating, the average concentration decreased to
57 (jg/L and is expected to continue declining.
Post-treatment monitoring confirms that no
contaminant rebound lias occurred in saturated
or vadose zone soil and that significant TCE
NAPL no longer exists in the treatment area.

The Triad work strategy is being modified as
lessons are learned throughout the remediation
process.  Cleanup at the second source  area
recently began, and remediation of the third area
is scheduled to begin in the spring of 2006.
Optimization of the site's existing pump-and-treat
system will continue for removal of remaining
dissolved-phase contaminants from the ground
water. Adetailed technical profile on this and other
Triad projects is available from the on-line Triad
Resource Center at http://wwwtriadcentral.Qrg.
                    [continued on page 4]
                                                                              Time (months)
                                                                    Interior Shallow Wells
                                                                    ~*~  MWE07A1
                                                                    -•-  MWF03A1
                                                                          MWF14A1
                                                                          MWH06A1
                                                                      a   MWI08A1
                                                                      t   MWJ04A1
                                                                          MWJ10A1
                                                                    ~^~  MWL07A1
                                                                       "  MWL10A1
                                                                          MWL10A1
                                                                          Begin ERH
                                                                          End ERH

-------
        [continued from page 3]
        Fort Lewis currently is designing and implement-
        ing an area-wide treatment performance
        assessment to evaluate thermal treatment system
        impacts on contaminant flux. In addition, an
Environmental Security Technology Certification
Program (ESTCP) demonstration is underway to
evaluate bioremediation and enhanced mass
transfer for dense nonaqueous-phase liquid
(DNAPL) source treatment
Contributed by Kira Lynch, USAGE
(206-764-6918 or
Iara.v.lvnch®nws02.usace.armv.mil)
                       Field Tests Show Enhanced Bioremediation following Cyclodextrin Flushing
        The U.S. Department of Defense (DOD)
        conducted a four-month field demonstration
        in 2002 to evaluate cyclodextrin-enhanced in-
        situ removal of organic contaminants from
        ground water at the Naval Amphibious Base
        Little Creek in Virginia Beach, VA(see January
        2003 Technology News and Trends). Under its
        ESTCP, DOD more recently analyzed the
        project's cost and performance data. The}" found
        that TCE concentrations in DNAPL declined
        an average of 77.3% from pre-treatment levels;
        initial aqueous TCE concentrations increased
        nine-fold; and solubility for 1,1,1 -trichloroethane
        (TCA)increasedupto 19-fold. OverallDNAPL
        saturation in the treatment wells decreased
        70-81%.

        The cost of cyclodextrin-enhanced flushing
        (CDEF)  was   evaluated based on  two
        deployment methods: injection and extraction
        (I/E) of cyclodextrin solutionusing several wells,
        and application of cyclodextrin in a multi-well
        push-pull (CPPT) mode. The CPPT approach
        cost approximately half of a comparable I/E
        system.  While the  cost  of  full-scale
        implementation of CDEF was found to be
        similar to other technologies, significant cost
        savings are associated with CDEF due to its
        ability to shorten remediation time.

        Researchers concluded that the use of other
        technologies may be required in conjunction
        with CDEF at some sites, such as those involving
        free-moving NAPL. In addition, CDEF may be
         Figure 4. Increased cyclodextrin
         concentrations in the subsurface correlated
         highly with increased CVOC concentrations
         during  the Denver brownfield pilot project,
         and were followed by concentration declines
         caused by both biodegradation and other
         attenuation processes.
most effective in initially lowering extremely
elevated concentrations of contaminant, followed
by a remediation approach to further reduce
concentrations to below MCLs. (The complete
ESTCP cost and perfonnance report [publication
number  CU-0113]  is  available  at  http://
www.estcp.org.)
CDEF technology was used more recently at a
fonner dry cleaning site in Denver, CO, as part of a
voluntary cleanup and brownfield redevelopment
effort. Enhanced reductive dechlorination (ERD)
was implemented at this site through a series of
moksses injections into a subsurface comprising
relatively tight sand, clay, and silt These conditions
required hydraulic  fracturing to enhance ground-
water flow and ensure delivery of the carbohydrate
material needed for  anaerobic  microbial
degradation. Through a network of 65 borings,
119 fractures at depths of 12-37 feet were initiated
over the extent of a ground-water plume of
tetrachlorethene (PCE) exceeding 5 mg/L. A
mixture of sand, guar gum, and chemical stabilizers
was introduced into the subsurface during
hydrofracturing to create highly permeable fractures
in each of the two water-bearing zones.  The
hydraulic radius of influence for these fractures
ranged from less than 5 to 75 feet
Once data confirmed the ERD system was
mature, a pilot-scale CDEF test was conducted
to evaluate the use of cyclodextrin to enhance
chlorinated VOC (C VOC) desorption from soil
while acting as  a carbohydrate  source to
stimulate the reductive dechlorination process.
The area's downgradient dissolved-phase
plume was already being treated using an in-
situ reactive zone (IRZ) strategy. In this "inject-
leave" application, any CVOC mobilization in
ground  water resulting from cyclodextrin
injection would be treated in the downgradient
ERZ.   Preliminary  results suggest  that
cyclodextrin increased the  aqueous-phase
concentration of total  CVOCs at this site by
approximately 350% (Figure 4).

A follow-up pilot study is underway at a second
commercial site  in Colorado where mixed
solvents (including 1,1,1 -TCA, TCE, methylene
chloride, and petroleum distillates) had leaked
from underground storage tanks. The study is
further evaluating the effectiveness of using
cyclodextrin inapush-pull application to remove
DNAPL  and   to   lower   source  area
concentrations to levels eventually treatable by

                  [continued on page 5]
                                                           VOC concentrations
                                                           enhancement
                                                           cyclodextrin
                                                           concentration
                                                                           0%
                          0     20     40     60    80    100
                         Time Since Cyclodextrin Injection (Days)
                     120    140
4

-------
 [continued from page 4]
 natural attenuation. In contrast to conventional
 application based on a "line-drive" hydraulic
 strategy involving multiple injection wells and
 distant extraction wells, the push-pull strategy
 allows cyclodextrin solution to be injected into a
 single treatment well and extracted from the same
 well after a short residence time. The push-pull
method avoids high rates of agent dilution (up
to 90%) that are common to the line-drive
method as well as the extensive ground-water
flow  modeling required  for line-drive
implementation In addition, operational costs
are lowered by the use of only a single well and
by the conservation  of costly but  recyclable
cyclodextrin agent.
Contributed by Assoc. Prof. Ttwmas Boving,
University of Rhode Island Department of
Geosciences (401-874-7053 or
boving&uri.edu), Craig Divine,  Ph.D.,
ARCADIS G&M (720-344-3500 or
cdivine(ci>arcadis-us.com) and Juli Park,
ARCADIS G&M (720-344-3500 or
ivark(a)arcadis-us. com)
                      "Supermulch" Amendment Expedites Reueyelation at Mining Sites
In 1997, the U.S. Department of Agriculture
(USDA) and University of Washington began
conducting a series of revegetation experiments
and demonstrations at the Bunker Hill Mining and
Metallurgical (Superfund) Site in central Idaho
(detailed in the July 2003 Technology News and
Trends). Amixture of municipal biosolids and wood
ash, called "Supermulch," was applied to an
approximate  seven-acre ground  surface
encompassing a fomier impoundment andhillsides
surrounding a formerzinc smelter. Througha unique
partnership, amendment materials for a portion of
the hillside remediation were provided by the City
of Coeurd'Alene and Avista Utilities. Theprqject's
innovative technical andbusinessstrategiesmerited
an award of engineering excellence from the
American Council of Engineering Companies
earlier this year.

Long-temimonitoring indicated that tissue samples
from plants grown in the Supermulch remained
within nomral ranges and that revegetation was
achieved on 100% of the amended plots. For
example, zinc concentrations in soil of the amended
plots ranged from 2,500 to 19,000 ppm, while zinc
concentrations in plant tissue ranged from 45 to 74
ppm-well within normal plant concentrations.
Analysis of seed germination as another key index
of revegetation showed that no germination had
occurred during the same time in control plots.

The revegetation approach developed at Bunker
Hill has  since been employed at other sites. In
1998, University of Washington researchers
assisted EPAs Environmental Response Team
(ERT) in designing an  amendment mixture for
alluvial tailings deposits at the California Gulch
Superfund site inLeadville, CO. Disposal or erosion
of high-pyrite tailings into the Arkansas River over
the past 100 years had created a 10-mile stretch of
barren mine deposits with high acidity and elevated
metal concentrations in soil, including 1,500-3,500
ppmlead,9-27ppm cadmium, and 1,500-3,400 ppm
zinc. In addition, high metal concentrations in
irrigated pastures had contributed to elevated rates
of plant toxicity and high mortality in grazing
livestock Removal of the tailings was not feasible
due to the potential for tailings to enter the river
during field activities, the high cost of replacement
topsoil, and the difficulty of locating an acceptable
repository for contaminated soil.

The Bunker Hill revegetation strategy was modified
at California Gulch to use higher rates of lime
amendment to neutralize the acidity of the tailings,
and to apply the Supermulch amendment directly
into (rather than atop) the tailings at a depth of 6-12
inches using a bulldozer and toothed ripper.
Inexpensive biosolids again were obtained partially
through a municipal partnership, with Denver
Metro,  the public wastewater treatment authority'
in Denver, CO.

Seven years later, approximately 35 acres of the
ten-mile riverside stretch have been restored and
now support dense vegetation (subject to recent
drought conditions). Analytical sampling
conducted by EPA and USDA indicates that
although total soil concentrations of metals of
concern have notchanged,extractable and available
lead, cadmium, and zinc are now below regulatory
standards. For instance, toxicity characteristic
leaching procedure (TCLP)-extractable cadmium
in the top foot of soil decreased from 1.32 ppm in
the untreated tailings to 0.06 ppm within two years
after  amendment addition

ERT conducted a four-year ecological risk
assessment of the treatment area, finding that metals-
relatedriskto wildlifeno longer exists. Inadditionto
standard extracts such as TCLP and the multiple
extraction procedure (MEP), die assessment
evaluated ecosystem endpoints' 'from the soil up;'
including microbial populations and activity in soil;
earthworm communities and metal uptake; plant
germination and metal concentration; field plant
species diversity; small mammal populations and
metal body burden; and fat head minnow survival
in re-entrained tailings of the upper Arkansas

                    [continued on page 6]
               Contact Us
     Technology Ne\vs and Trends
             is on the NET!

    View, download, subscribe, and
             unsubscribe at:

        http://www.epa.gov/tio
             http://cluin.org

   Technology News and Trends
   welcomes  readers' comments
     and contributions. Address
          correspondence to:
                Ann Eleanor
     Office of Superfund Remediation and
           Technology Innovation
                  (5102G)
    U.S. Environmental Protection Agency
             Ariel Rios Building
         1200 Pennsylvania Ave, NW
           Washington, DC 20460
            Phone: 703-603-7199
             Fax:703-603-9135

-------
                                                    Solid Waste and
                                                    Emergency  Response
                                                    (5102G)
                                     EPA 542-N-05-004
                                     July 2005
                                     Issue No. 19
 United States
 Environmental Protection Agency
 National Service Center for Environmental Publications
 P.O. Box 42419
 Cincinnati, OH 45242
            Presorted Standard
            Postage and Fees Paid
            EPA
            Permit No. G-35
 Official  Business
 Penalty for Private Use $300
  [continued from page 5]
  River. The evaluation found that biosolids and
  lime amendment had reduced metal toxicity
  sufficiently to restore ecosystem function for all
  endpoints, as highlighted by key findings:
   > Mcrobial function in the biosolids-amended
     tailings (as measured by carbon dioxide evo-
     lution) in the first year after amendment addi-
     tion was 10 times higher than in untreated
     tailings and four times higher than in uncon-
     taminated soil.
   ^ Earthworm survival  averaged 80% in the
     treated tailings, as compared to 1992-2000tests
     showing 0% in the untreated tailings and 99%
     in the laboratory control soil.
   > SmaflmanmTalpopuktiaTsweresimilartothose
     in offsite regions, and laboratory analysis of
     small mammal target organs showed no signs
     of malfunction or damage.
As a result of Supemiulch amendment, cattle-
grazing has resumed on land that was barren for
more than 80 years, aiidapubHcparkwithafishing
area now operates on one of the fonner tailings
deposits. Similar results have been observed after
this technology was initiated at the Qronogo
Duenweg Mining Belt site in Jasper County, MO,
in!999-2001. The approachnowis under evaluation
for use at a wetland tailings repository at the Bunker
Hill site and at alluvial tailings deposits outside of
Prescott, AZ.

Contributed by Salfy Brown, University of
Washington (206-616-1299 or
slb(a)UM'ashington. edit) arid Harry Compton,
U.S. EPA-  ERT (732-321-6751 or
comvton. harr\(Sieva. sov)
   Superfund Turns 25
This year marks the 25th
anniversary of the Superfund
program. To commemorate this
milestone, the U.S. EPA is
developing a series of oral and photo
projects covering Superfund history,
its social complexity, and important
events, and will launch a national
discussion ofthe program's
changing nature. Information on
participation in these projects or
future viewing ofthe anniversary
documentation is available athttp://
epa .qov/superrund/25anniversarv.
EPA is publishing this newsletter as a means of disseminating useful information regarding innovative and alternative treatment techniques and
technologies. The Agency does not endorse specific technology vendors.

-------