Superfund Record of Decision Southern Maryland Wood Treating Hollywood Maryland


                                    EPA/ROD/R03-95/197
                                    1995
EPA Superfund
     Record of Decision:
     SOUTHERN MARYLAND WOOD TREATING
     EPA ID: MDD980704852
     OU02
     HOLLYWOOD, MD
     09/08/1995

-------
Text:
                           RECORD OF DECISION

                  SOUTHERN MARYLAND WOOD  TREATING SITE

                 HOLLYWOOD, ST. MARY'S  COUNTY,  MARYLAND
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION 3, PHILADELPHIA, PENNSYLVANIA
SEPTEMBER 1995

-------
                       RECORD OF DECISION
               SOUTHERN MARYLAND WOOD TREATING SITE

                          DECLARATION

Site Name and Location

Southern Maryland Wood Treating Site
Hollywood, St. Mary's County, Maryland

Statement of Basis and Purpose

This decision document presents the selected remedial action for the Southern Maryland Wood Treating Site
("the Site"), in Hollywood, Maryland, which was chosen in accordance with the reguirements of the
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 ("CERCLA"), as amended by
the Superfund Amendments and Reauthorization Act of 1986 ("SARA") and,  to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan ("NCP").  This decision document explains
the factual and legal basis for selecting the remedy for this site.  The information supporting this remedial
action decision is contained in the Administrative Record for this site.

The Maryland Department of the Environment concurs with the selected remedy.  However,  because MDE believes
that EPA has selected a remedy which effectively eliminates the Site contamination through treatment and
offsite disposal, MDE does not believe extended or indefinite ground water monitoring beyond 5 years is
warranted.

Assessment of the Site

Pursuant to duly delegated authority, I hereby determine, pursuant to Section 106 of CERCLA, 42 U.S.C. §
9606, that actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this Record of Decision ("ROD"), may present an imminent and
substantial threat to public health, welfare, or the environment.

Description of the Selected Remedy

This is the second and final phase of remedial action for the Site.  The first phase involved the
installation of a sheet pile barrier wall around the most highly contaminated area of the Site, the
"containment area".  This phase addresses soil and sediment contamination and non-agueous phase liguids
("NAPLs") which are the principal threats remaining at the Site and are a source of  contamination to the
ground water and surface water.  Because the soil and sediments will be treated to levels that are protective
of human health and the environment before backfilling onsite, and the NAPLs will be disposed offsite, the
Site will not reguire long-term management.

The major components of the selected remedy include the following:

!         Dewatering of the  containment area in preparation for
          the excavation of subsurface soil and dense non-agueous
          phase liguids ("DNAPLs")  below the water table followed
          by onsite treatment of water generated in the dewatering
          process and discharge of treated water to the west tributary;

!         Excavation of approximately 97,000 cubic yards  ("CY")  of soil
          from within and outside of the sheet pile wall and dredging
          of sediments from the onsite pond and segments of the east
          and west tributaries that contain contaminants in excess of
          the established cleanup levels;

!         Dewatering of saturated soils/sediments onsite in preparation

-------
for treatment by thermal desorption, followed by onsite
treatment of water generated in the dewatering process and
discharge of treated water to the west tributary;

! Staging of excavated soil/sediments onsite in preparation for
dewatering, following dewatering in preparation for treatment
by thermal desorption, and following thermal desorption in
preparation'for backfilling. Also, onsite staging of NAPLs
collected during excavation and dewatering, water treatment
residues, recondensed contaminants from the thermal
desorption treatment process, and any grossly contaminated
soil/sediment that is not amenable to treatment by thermal
desorption prior to offsite shipment for treatment and disposal;

! Onsite treatment of excavated soils and sediments by a
thermal desorption process;

! Offsite treatment and disposal of desorbed, recondensed
contaminants from the thermal desorption treatment process,
NAPLs collected during excavation and dewatering, water
treatment residues, and any grossly contaminated
soil/sediment that is not amenable to treatment by thermal desorption;

! Sampling of treated soils and sediments to ensure delisting
levels have been achieved;

! Backfilling with clean fill below the water table in the
containment area and with treated soil/sediments above the
water table in the containment area and in all other
excavated areas;

! Pumping and treating of surface water from the onsite pond
until the sources of contamination to the surface water
i.e., soil, sediment, ground water) are remediated.
Treatment of surface water in onsite water treatment system
followed by discharge to the west tributary;

! Ground water, stream and wetlands monitoring;

! Implementation of institutional controls temporarily
restricting ground water use in the shallow aguifer;

! Building demolition and cutting off of the sheet pile wall
following remediation, as determined necessary. Offsite
disposal of building rubble and sheet piling; and

! Maintenance of perimeter fencing until access restrictions
are no longer necessary.

Declaration of Statutory Determinations

The selected remedy is protective of human health and the environment, complies with Federal and State
reguirements that are legally applicable or relevant and appropriate to the remedial action, and is
cost-effective. This remedy utilizes permanent solutions and alternative treatment (or resource recovery)
technologies to the maximum extent practicable, and it satisfies the statutory preference for remedies that
employ treatment that reduce toxicity, mobility, or volume as a principal element.

-------
Because the selected remedy may not allow for unlimited use of and unrestricted exposure to the Site within
five years of initiation of the remedial action, a policy review of the Site will be conducted within five
years of the completion of physical construction of the remedial action.  Such review shall be
conducted in accordance with EPA guidance set forth in Structure and Components of Five-Year Reviews, May 23,
1991, OSWER Directive 9355.7-02 and Supplemental Five-Year Review Guidance, OSWER 9355.7-02A, to ensure that
the remedy continues to provide adequate protection to human health and the environment.  Such
policy reviews will be conducted no less than every five years thereafter until EPA determines that there are
no hazardous substances remaining on the Site that prevent unlimited use of and unrestricted exposure to the
Site.



W. Michael McCabe                                      Date
Regional Administrator
Region 3

-------
                               TABLE OF CONTENTS

1.0       SITE NAME,  LOCATION,  AND DESCRIPTION 	  1

2.0       SITE HISTORY AND ENFORCEMENT ACTIVITIES 	  1

3.0       HIGHLIGHTS OF COMMUNITY PARTICIPATION 	  4

4.0       SCOPE AND ROLE OF RESPONSE ACTION 	  5

5.0       SUMMARY OF SITE CHARACTERISTICS 	  6
          5.1       Hydrogeology, Geology,  Soils 	  6
          5.2       Nature and Extent of Contamination 	  7
                    5.2.1   Soils in Land Treatment Area and Other Areas
                           Outside Containment Area 	  8
                    5.2.2   Ground Water Outside the Containment Area 	  8
                    5.2.3   Soils within the Containment Area 	  9
                    5.2.4   Ground Water and NAPLS Within the Containment
                           Area  	 10
                    5.2.5   Surface Water and Sediments 	 10
                    5.2.6   Dioxin and Furan Contamination 	 11
          5.3       Volume of Contaminated Soil and Sediment 	 12

6. 0       SUMMARY OF SITE RISKS  	 12
          6.1       Contaminants of Concern 	 12
          6.2       Human Health Risk Assessment 	 13
                    6.2.1   Exposure Assessment 	 13
                          6.2.1.1  Exposure Pathways 	 13
                          6.2.1.2  Estimation of Exposure Point
                                   Concentrations 	 14
                          6.2.1.3  Populations at Risk and Exposure
                                   Estimates 	 16
                    6.2.2   Toxicity Assessment 	 17
                    6.2.3   Risk Characterization 	 19
                          6.2.3.1  Carcinogenic Risk 	 19
                          6.2.3.2  Noncarcinogenic Risks 	 20
          6.3       Environmental Risks 	 21
                    6.3.1   Contaminants of Concern 	 21
                    6.3.2   Terrestrial Routes of Exposure 	 21
                    6.3.3   Aguatic Routes of Exposure 	 22
                    6.3.4   Effects On Stream Ecosystems 	 22
          6. 4       Conclusion 	 22

7.0       REMEDIAL OBJECTIVES AND CLEANUP LEVELS 	 23

8 . 0       DESCRIPTION OF ALTERNATIVES 	 24
          Common Elements 	 24
          Alternative 1 	 26
          Alternative 2 	 27
          Alternative 3 	 27
          Alternative 4 	 28
          Alternative 5 	 28
          Alternative 6 	 29
          Alternative 7 	 30
          Alternative 8 	 31
          Alternative 9 	 32
          ARARs Common Among Alternative 	 33

-------
          Delisting of RCRA Hazardous Wastes 	 35
          During and Post-Remediation Risk Assessment Summary 	 36
          General Statement Regarding Ecological Resources 	 38

9.0       SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 	 38
          9.1   Overall Protection of Human Health and the
                Environment 	 38
          9.2   Compliance with ARARS 	 40
          9.3   Long-Term Effectiveness and Permanence 	 40
          9.4   Reduction of Toxicity, Mobility or Volume through
                Treatment 	 41
          9.5   Short-Term Effectiveness 	 41
          9.6   Implementability 	 42
          9.7   Cost 	 43
          9.8   State Acceptance 	 44
          9.9   Community Acceptance  	 44

10.0      SELECTED REMEDY:  DESCRIPTION AND PERFORMANCE STANDARDS             44
          10.1   Excavation of Soils, Dredging of Sediments,  and DNAPL
                 Removal 	 46
          10.2   Onsite Thermal Desorption of Excavated Soils and
                 Dredged Sediments 	 48
          10.3   Backfilling of Clean Fill and Treated Soils and
                 Sediments 	 50
          10.4   Surface Water Pumping and Treating
              51
          10.5   Ground Water Monitoring 	 51
          10.6   Stream and Wetland Monitoring
              53
          10.7   Institutional Controls 	 54
          10.8   Building Demolition  	 55
          10.9   Sheet Pile Wall 	 55
          10 10   Perimeter Fencing  	 55
          10.11   Miscellaneous Performance Standards 	 55

11.0      GROUND WATER CONTINGENCY 	 56

12.0      STATUTORY DETERMINATIONS 	 57
          12.1   Protection of Human Health and the Environment 	 57
          12.2   Compliance with Applicable or Relevant and Appropriate
                 Reguirements 	 58
          12.3   Cost-Effectiveness  	 58
          12.4   Utilization of Permanent Solutions and Alternative
                 Treatment Technologies to the Maximum Extent
                 Practicable 	 58
          12.5   Preference for Treatment as a Principal Element 	 59

13.0      DOCUMENTATION OF SIGNIFICANT CHANGES 	 59

FIGURES

TABLES
RESPONSIVENESS SUMMARY

-------
DECISION SUMMARY

1.0 SITE NAME, LOCATION AND DESCRIPTION

The Southern Maryland Wood Treating Site ("SMWT" or "Site"), approximately 25 acres in size, is located just
west of Maryland Route 235 on a 96 acre parcel of land approximately one mile north of Hollywood, Maryland in
St. Mary's County (Figure 1). The operation of a pressure treated wood preservation facility on the Site for
many years resulted in contamination of soils, ground water, surface water and stream sediments with wood
preserving chemicals. No wood treating activities are currently performed onsite.

Figure 2 shows the primary Site features. The Site is bounded by residential, agricultural, and wooded
tracts of land. An onsite freshwater pond discharges to Old Tom's Run (also referred to as the "west
tributary"), which eventually reaches Breton Bay and finally the Potomac River. Currently the only building
structures left onsite that were once associated with the wood preservation business are a pole barn
previously used for wood storage, and a small house in the upper site area formerly used as an office.

The original process building, which has since been demolished, housed the wood pressure treatment operations
including two treatment vessels or retorts. Wood and chemical preservatives were introduced into the vessels
which were subseguently pressurized in order to treat the wood. Several large vertical
tanks previously located next to the process building contained the chemical preservatives pentachlorophenol
("PCP") and creosote, which were used in the wood treating process.

According to the 1990 census, the population of St. Mary's County is approximately 76,000. Because the
county is located along 400 miles of shoreline on the Potomac and Patuxent Rivers and the Chesapeake Bay, the
population increases substantially in the summer season. On a more local basis, there are several
residential subdivisions and numerous houses within an approximate 2-mile radius of the Site.

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

The Site was owned by Herbert and Louie Giddings from 1964 until 1975 when ownership was transferred to the
Southern Maryland Wood Treating Corporation ("SMWT Corp."). The wood treating facility was owned and
operated by the SMWT Corp., and subseguently operated by L.A. Clarke and Son, Inc. ("L.A. Clarke"), from 1965
to 1978 as a pressure treated wood preservation business. Creosote and PCP were used as wood preservatives at
the Site.

The six unlined lagoons depicted in Figure 2 were used for disposal of liguid waste from the process. As a
result of such disposal, onsite soils and ground water beneath the lagoons became contaminated. Non-agueous
phase liguids ("NAPLs"), both light ("LNAPLs") and dense ("DNAPLs"), are also found in the
subsurface beneath the lagoons and above the underlying clay layer. Additionally, due to ground water
discharge to the pond from the lagoon area, surface water and sediment in the onsite pond and sediment in the
west tributary became contaminated. Sediments in the east tributary are also contaminated, most
likely due to surface water runoff from contaminated soils onsite. Storage of treated wood onsite resulted
in surface soil contamination in the upper site and northeast tank areas.

In the early 1970's, the operators of the facility submitted an application to the local health department
for the construction of a new onsite well. Upon inspection of the Site, the St. Mary's County Department of
Environmental Hygiene found evidence of possible contamination and rejected the application.
Recognizing that the Site constituted a potentially serious source of contamination, the County instituted a
program of sampling and inspection.

The State of Maryland ("State") subseguently entered into negotiations with the operator, reguesting that the
Site be cleaned up. However, in 1978, L.A. Clarke and Son, Inc., which had become sole shareholder in the
SMWT Corp. in 1975, filed for bankruptcy and ceased wood treating operations. To enforce a site clean-up,
the Maryland Water Resources Administration instituted a legal action against L.A. Clarke and Sons, Inc. In
November 1980, the St. Mary's County Court issued a Consent Decree reguiring a complete restoration of the
Site.

-------
Pursuant to a petition for contempt filed by the State with the St. Mary's County Court, L.A. Clarke began an
initial cleanup of the Site in 1982. Liquids from the lagoons were sprayed into the woods behind the Site
("spray irrigation area"). The sludge from the lagoons was excavated and mixed with wood chips, composted
sewage sludge and top soil, then spread in a previously uncontaminated area on the southeastern section of
the property in an attempt to bioremediate the contaminants. The excavated lagoons were backfilled and
graded. This attempt at land treatment of the sludge was unsuccessful, and resulted in the
contamination of several additional acres of the property, now referred to as the "land treatment area".

On March 14, 1985, EPA initiated its first response action at the Site. After the discovery of contaminated
material seeding into the fresh water pond, EPA started a removal action. During this action, approximately
1,400 cubic yards ("CY") of contaminated sediment were excavated from the pond. This sediment was stabilized
with cement kiln dust and encapsulated onsite in an impermeable synthetic liner to the east of the former
lagoon area within what is now the containment area.

The Site was proposed for inclusion on the National Priorities List ("NPL") on October 1, 1984, and listed on
the NPL on June 1, 1986.

In 1988, EPA concluded a Remedial Investigation (RI) and Feasibility Study (FS) at the Site. Based on the
findings of these studies, EPA issued a Record of Decision (ROD) on June 29, 1988. The ROD called for
construction of a subsurface barrier wall around the former lagoon area, which was found to contain a
plume of contaminated ground water; excavation and onsite incineration of contaminated soil from the former
lagoon area, the land treatment area, and other areas of the Site; onsite incineration of liquids and solids
contained in tanks and retorts; demolition of buildings; and pumping and treatment of
contaminated ground water. The Maryland Department of the Environment ("MDE") concurred with the ROD,
provided that the cost of the remedy could be substantially reduced during design.

In order to expedite the start of cleanup work at the Site, the remedial action was broken down into two
phases. The first phase was the installation of a sheet pile barrier wall around the former lagoon and
process areas (see Figure 2). This area is now referred to as the "containment area". Construction of the
sheet pile wall was completed in November of 1990. The second phase included the remaining components of the
selected remedy. In May 1992, design of the incineration and ground water treatment components had reached
the 95% stage. At that time, it was apparent that a substantial cost reduction could not be achieved,
resulting in Maryland's inability to fund its required 10% share of site remediation costs. At the same
time, local citizens and local government entities expressed opposition to an onsite incinerator. The design
work was suspended and EPA proposed to conduct a Focused Feasibility Study ("FFS") to reevaluate the remedy
for the Site.

On June 29, 1993, a second removal action was initiated to address certain immediate threats at the Site
while the FFS was being conducted. This action included the demolition of several buildings that were in
danger of collapse; the removal and offsite disposal of liquid and solid waste in numerous tanks and
the retorts, and over 350 drums of investigation-derived waste; the re-covering of the pile of previously
excavated sediment; the construction of an underflow dam to reduce the flow of floating and sinking material
from the onsite pond to the west tributary; the construction of a trench upgradient of the pond to collect
contaminated ground water and, if possible, DNAPL; and the construction of a water treatment facility to
treat water from the pond and/or the trench prior to its discharge to the west tributary. The water
treatment facility became fully operational in June 1995 and will be operated on a continual basis through
the remedial action.

The FFS was conducted from May 1992 to February 1995, at which time the Final FFS Report was issued. This
Record of Decision ("ROD") is based on the remedial alternatives developed and evaluated in the FFS, as well
as other Site characterization information found in the Administrative Record file.

EPA conducted a potentially responsible party ("PRP") search from 1985 to 1987. The PRPs identified by this
search included the following: (1) SMWT Corp.; (2) L.A. Clarke & Son, Inc., parent company of SMWT Corp.;
(3) Ted Curtas, President of SMWT Corp. and manager of site operations; (4) Michael Clarke, former
officer, director, and stockholder of the SMWT Corp.; and (5) Louie Giddings, former property owner who
leased the property to SMWT Corp.

-------
On June 6, 1988, EPA issued Special Notice Letters affording the PRPs the opportunity to implement the remedy
selected in the 1988 ROD.  As no good faith proposal to implement the remedy was received and EPA had
determined that none of the PRPs was financially viable, EPA proceeded with the remedial design/remedial
action  ("RD/RA").   Due to the absence of viable PRPs, no legal action has been instituted regarding cleanup
of the Site.  However, EPA has issued a notice to the property owner that EPA intends to file a Superfund
lien on the property in accordance with §107(1) of CERCLA.

3.0     HIGHLIGHTS OF COMMUNITY PARTICIPATION

During the period that EPA was conducting the FFS for the Site, extensive community involvement was
maintained.  EPA generated several drafts of the FFS Report and a Post-Remediation Human Health Risk
Assessment that were released to the public for comment.  Public meetings were held periodically to keep the
community informed of the progress of the FFS and to solicit input from the community.  In addition, monthly
telephone conference calls were conducted with EPA, MDE, local press, and community members to update the
public on the progress of the project.

The Final FFS Report for the Site was released to the public on February 24, 1995, and the Proposed Remedial
Action Plan ("PRAP#) was released to the public for comment on March 22, 1995.  These documents were made
available to the public in the Administrative Record file maintained at the EPA Region 3 office in
Philadelphia,  PA,  and at the St. Mary's County Library in Leonardtown, MD.  The notice of availability of
these documents was published in The Enterprise newspaper on March 22 and 29, 1995.  A public comment period
on the documents was held from March 22, 1995 to April 21, 1995.  In addition, EPA held a public
meeting on March 30, 1995 at the Carter State office Building in Leonardtown, MD.  At that meeting,
representatives from EPA and MDE answered guestions about conditions at the Site and the remedial
alternatives under consideration.  A response to the comments received during the public comment period is
included in the Responsiveness Summary, which is a part of this ROD.

This decision document presents the selected remedial action for the Southern Maryland Wood Treating Site, in
Hollywood, Maryland, chosen in accordance with the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 ("CERCLA"), as amended by the Superfund Amendments and Reauthorization Act of
1986 ("SARA"), and, to the extent practicable, the National Oil and Hazardous Substances Pollution
Contingency Plan ("NCP"), 40 C.F.R. Part 300.  The selection of the remedial action for this Site is based on
the Administrative Record.

4.0     SCOPE AND ROLE OF RESPONSE ACTION

The removal actions discussed above in Section 2.0 addressed certain immediate threats at the Site and
removed a large volume of waste contained in drums, retorts, tanks and buildings onsite. This remedy
addresses the remaining sources of contamination (NAPLs in the subsurface in the containment area, lagoon
sludge in the land treatment area, and contaminated soils and sediments in the containment, northeast tank,
upper site, and land treatment areas, and the tributaries), as well as contaminated ground water and surface
water.   EPA considers the NAPLs and contaminated soil in the containment area and the lagoon sludge in the
land treatment area to be principal threat wastes,  meaning that the material includes or contains high
concentrations of hazardous substances, pollutants, or contaminants and acts as a source of contamination to
other media.  Pursuant to the NCP at 40 CFR §300.430(a) (1) (iii), EPA expects to use treatment to address the
principal threats posed by a site, wherever practicable.

This ROD presents a final remedial action that will address all contaminated media and all potential routes
of exposure to human or environmental receptors.  The goal of this cleanup action is to ensure that future
residents and ecological receptors will not be exposed to an unacceptable risk posed by Site soil, and ground
water.   In addition, this action will prevent future risk to ecological receptors posed by exposure to
contaminated surface water and sediment.

5.0     SUMMARY OF SITE CHARACTERISTICS

5.1     Hydrogeology Geology, Soils

-------
Topography - Topographic relief across the Site is about 35 feet, with elevations ranging between 119 to 154
feet above mean sea level. The Site slopes steeply from the upper site/northeast tank/process/land treatment
areas down to the pond. The Site lies on a drainage divide such that runoff from the site
discharges to tributaries that straddle the Site to the east and west. Both of these tributaries discharge
to the Potomac River via Brooks Run and Mcintosh Run. Regionally, the Site is located close to the drainage
divide between the Potomac and Patuxent River Basins.

Geology - Geologically, the Site lies within the Atlantic Coastal Plain physiographic province which is
composed of unconsolidated gravels, sands, silts, and clays. Soil borings indicate that the soils onsite are
composed primarily of silty and clayey sand which extends to a maximum depth of about 40 feet below ground
surface ("BGS"). These are known as the "Upland Deposits," the uppermost water-bearing zone in the area of
the Site. It is likely that a large portion of the surface and near-surface soils at the Site have been
disturbed and reworked by past disposal operations (i.e., lagoons and land treatment) and remedial activities
(i.e., excavation and backfilling).

The Upland Deposits are separated from the next sandy geological unit, the Chesapeake Group, by a low
permeability dense blue clay which is approximately 20 feet thick in the area of the Site. While there are
some domestic wells in the vicinity of the Site that obtain water form the Upland Deposits, drinking water
supplies in the area are primarily obtained from the confined Aguia and Piney Point-Nanjemoy aguifers. These
water-bearing units are located approximately 285 to 600 feet BGS and are separated from the Upland Deposits
by several layers of alternating sands and clays. Table 1 includes a summary of a drilling log for an onsite
production well that describes the layers found beneath the Site.

According to the May 1988 Remedial Investigation Report, a survey of available well logs in the area of the
Site was conducted, six ground water supply wells, including the onsite production well which has since been
abandoned, were found to be screened in the Aguia and Piney Point-Nanjemoy aguifers. Two residences were
found to utilize shallow water table wells for their water supply. These wells are located approximately 200
yards northwest and 400 yards north of the Site, respectively. With regard to ground water flow in the water
table aguifer, this would be considered upgradient from the Site.

Hydrogeology - The ground water flow pattern in the shallow water table aguifer (Upland Deposits) above the
first blue clay encountered beneath the Site, has been altered to some degree by the installation of the
sheet pile wall in 1990. Figures 3 and 4 show the ground water elevation contours and flow directions from
February 1988 (pre-sheet pile wall) and May 1991 (post-sheet pile wall), respectively. These figures
illustrate that the pond and the stream flowing from the pond (west tributary) are the main hydrogeologic
controls in the containment area. The shallow ground water flow in this local area is towards the pond and
stream indicating that they act as ground water discharge points.

Ground water elevations in most wells within the containment area have significantly decreased since the
installation of the sheet pile wall. The decline in ground water elevations and changes in the flow patterns
indicate that the installation of the wall has decreased the ground water flow from outside the containment
area into the containment area. In the eastern portion of the containment area where the ground water divide
was previously identified, ground water infiltrating into this zone appears to
be trapped by the sheet pile wall thus resulting in a rise in the ground water level. Although there has
been some modification in the ground water flow outside of the containment area, the flow direction remains
essentially unchanged (i.e., east and south).

Ground water elevation and contours in the deeper sand bearing stratum below the blue clay are depicted in
Figure 5. Ground water flow in this stratum is to the southeast.

5.2 Nature and Extent of Contamination

The SMWT facility used the typical wood treating preservatives, creosote and PCP. Creosote is an oily brown
to black liguid which is either used full strength or diluted with petroleum oil or coal tar. Practically
insoluble, it is denser than water and is made up of a complex mixture of organic compounds. A typical
creosote composition includes 85% polynuclear aromatic hydrocarbons (PAHs), 10% phenolic compounds, and 5%
nitrogen-, sulfur-, or oxygen-containing heterocycles. Technical grade PCP used to treat wood contains

-------
85-90% PCP, other chlorophenolic compounds, and chlorinated dibenzo-dioxins and furans (0.1%). PCP and
several of the PAHs are classified as probable human carcinogens. Table 2 lists the chemicals detected in
ground water, soils, and sediments at the Site, including various creosote and PCP compounds.

At the SMWT Site, the wood treating process, which used these oil-based preservatives, produced sludge water
and significant guantities of process wastewater that were discharged in several unlined onsite lagoons. In
addition to the former lagoon area, Table 3 lists the various areas of the Site shown in Figure 2 and the
probable causes of contamination in each area that resulted from the operation of the wood treatment
business. A more detailed description of the contamination found in each area is presented below. This
information is summarized from data gathered during the remedial investigation completed in 1988, a
pre-design study conducted in 1991-1992, and a FFS conducted in 1992-1994. Soil boring locations from the
pre-design investigation and monitoring wells installed during the RI and pre-design are shown in Figure 6.
Additional soil borings and monitoring wells installed during the FFS are shown in Figure 7.

5.2.1 Soils in Land Treatment Area and Other Areas Outside Containment Area

The stratigraphy of the land treatment area shows approximately 1.5 feet of sandy soil, followed by 6 to 8
inches of composted lagoon sludge left from the attempt at land treatment, and then contaminated soils to a
maximum depth of about 5 to 7 feet BGS. Contaminants consist primarily of PAHs in the thousands of parts
per million ("ppm") range in the upper two feet BGS and to a lesser extent PCP at concentrations as high as
180 ppm. At the 5 to 7 foot depth, the maximum PAH concentration was only 77 ppm. These soils are considered
a principal threat because they are highly contaminated with wood treating wastes. Below the 5 to 7 foot
depth, soils are not contaminated.

Surface soils at a depth of approximately 0 to 2 feet are also contaminated with PAHs in portions of the
upper site, process, and northeast tank areas of the Site. In the upper site area, PAHs are found in two
locations (SO-7 and SO-4) in the surface soils at a few parts per million and at a few other locations in
the hundreds of parts per billion ("ppb") range. Similarly, in the northeast tank area, a few shallow
samples show PAH concentrations in the hundreds of parts per billion. At SO-15 total PAHs ("TPAHs") are
found at approximately 15 ppm in the surface soil. Carcinogenic PAHs ("CPAHs") make up about 7 ppm of
the contaminants at that location. At MW-23 TPAHS are at 28 ppm (11 ppm CPAHs) in the surface soil.

In the spray irrigation area TPAH concentrations of 3 ppm (l.Sppm CPAHs) are found at SO-26 in the surface
soil. In a few other locations TPAHs occur in the hundreds of parts per billion range. Beyond the fence
line, contamination is found only at SO-31 at less than 1 ppm in surface soil.

5.2.2 Ground Water Outside the Containment Area

Ground water in the land treatment area is not significantly impacted and shows very low levels of
contamination, a few parts per billion base-neutral and acid extractable compounds ("BNAs"), which include
the PAHs and various phenolic compounds. Volatile organic compounds ("VOCs") have not been detected in the
ground water in this area.

In the upper site and northeast tank areas, concentrations of BNAs are not found above 11 ppb and no VOCs are
present. At MW-23 BNA concentrations are at 121 ppb (mostly naphthalene) and VOCs at 9 ppb. The spray
irrigation area showed 1 ppm BNAs at MW-12 and 155 ppb petroleum hydrocarbons, including benzene,
toluene, ethylbenzene, and xylene ("BTEX"). MW-27 showed 1 ppb naphthalene in a sample collected in early
1995.

There are four wells, MW19-22, screened in the sand unit just below the blue clay beneath the Site. During
the Pre-design study, no contamination was detected in these wells. Beginning in March 1994, these wells
have been sampled on a regular basis to monitor whether contamination is moving through the clay into deeper
aguifers.

During the March 1994 sampling event, several PARs and phthalates were detected in these wells at individual
concentrations ranging from less than 1 ppb to approximately 10 ppb. This may be due to cross-contamination
of the samples from air borne contamination resulting from excavation activities conducted simultaneously

-------
with that sampling event. In all subsequent sampling events, no PAHs have been detected. Only one phthalate
has been detected at a maximum of 33 ppb. This compound is frequently introduced during sampling and
laboratory analysis and its presence is believed to be the result of sample handling and not site-related.
These data results indicate that the clay layer is an effective confining unit and prevents contaminants in
the shallow aquifer above the clay from migrating into the sand unit below the clay.

5.2.3 Soils within the Containment Area

Soil within the containment area is heavily contaminated with PARs at depths ranging from 0 to 2 feet BGS to
the top of the clay layer underlying the Site, particularly in the area where the lagoons were located. The
depth to clay varies in the containment area from about 8 to 40 feet due to the change in surface topography
from the upper portion of the Site down to the pond. PAR concentrations range from the tens to thousands of
parts per million. PCP at 29 ppm was found only at MW-28 in a surface soil sample. The pond sediments
excavated during the first removal action in 1985 remain covered with plastic in the containment area. These
sediments are contaminated with PARs at concentrations greater than 1000 ppm. No PCP has been detected in
the s e s ediment s.

The soils within the containment area are considered a principal threat because they are highly contaminated
with wood treating wastes and may act as a continuing source of contamination to
ground water and surface water.

5.2.4 Ground Water and NAPLS Within the Containment Area

Ground water within the containment area is heavily contaminated with BNAs and VOCs. Figure 8 shows the area
of shallow ground water contamination delineated during the RI. The location of the sheet pile wall is based
on that delineation and is constructed such that almost the entire contaminated area is contained within the
wall. All monitoring wells show high concentrations of VOCs except MW-09 where no VOCs are found. VOCs
ranged from 355 - 2990 ppb. BNAs range from 0.065 - 270 ppm. TPARS ranged from 4-31 ppm with CPAHS ranging
from non-detect to 1700 ppb.

Both LNAPLs and DNAPLs are found in monitoring wells within the containment area in the area where the waste
water lagoons were once located. DNAPL levels range from about 1 to 4 feet in monitoring wells MW-28, MW-30,
and MW-31. The LNAPL is most likely associated with the carrier oil in the creosote and PCP
formulations used at the Site and tends to float on top of the water table. The NAPLs within the containment
area are considered a principal threat because they are highly contaminated with wood treating wastes and act
as a continuing source of contamination to ground water and surface water.

Because DNAPL is more dense than water, its movement in the subsurface is largely dependent on gravity and
pressure gradients rather than on hydrodynamic factors. Thus, due to gravity, the DNAPL at the SMWT site has
migrated through the subsurface from the original source, the waste water lagoons, and come to rest on
the blue clay layer beneath the Site. The clay layer acts as a low permeability barrier to vertical
migration of ground water and DNAPL. It ranges in thickness from 19 to 23 feet, is laterally extensive in
the vicinity of the wells, borings and sheet piling of the containment area, and has a very low vertical
permeability of 10-7 - 10-8 cm/sec. The DNAPL will not move from this position unless the pressure gradient
of any pool or potentially mobile (continuous) fraction is disturbed in some way. In addition, because the
density of the DNAPL is only slightly greater than water, several meters of DNAPL would have
to be sitting on the clay to be able to displace the water in the clay pore spaces to allow the DNAPL to move
into the clay. At this site, a maximum of only a few feet of DNAPL has been found in wells underlying the
original source areas in the containment area.

5.2.5 Surface Water and Sediments

Surface water samples from the onsite pond show higher levels of contamination (> 1 ppm PAHs) in the upper
reaches of the onsite pond than in the lower section of the pond (< 40 ppb PARs). The upper section of the
pond receives contamination from ground water discharge from the containment area. The lower section of the
pond is separated from the upper section by an earthen dam. Surface water samples collected from the west
tributary in September 1994 show that, under normal weather conditions, very little contamination is flowing

-------
from the pond via surface water due to the underflow dam installed during the most recent removal action.
VOC concentrations were only 11 ppb in a sample collected just outside the sheet pile wall. When compared to
ground water and surface water within the sheet pile wall, these levels are very low. Further downstream,
contaminant concentrations were even lower. Surface water from the pond is
currently pumped and treated in the onsite water treatment system before being discharged to the west
tributary.

During the RI, stream sediment samples collected along the west tributary were found to be contaminated with
total PAHs at concentrations in the range of tens of parts per million (ppm) at a distance of up to 1,900
feet downstream of the onsite pond. Along the east tributary, contaminant concentrations in sediments ranged
from non-detectable to approximately 2 ppm in a sample collected near the confluence of the east and west
tributaries. Contaminants detected in sediments were similar to those detected in onsite surface soils.
Both the eastern and western tributaries were resampled during the Pre-Design Study; the most recent round of
sampling was conducted in February 1992. Concentrations of total PAHs of up to 266 ppm and CPAHs up to 218
ppm were detected approximately 1,500 feet from the Site in the west tributary. CPAHs were only
as high as 6 ppm in a gully that leads from the northeast tank area to the east tributary. Samples collected
in Old Tom's Run beyond the confluence of the west and east tributaries contained no BNAs.
5.2.6
Dioxin and Furan Contamination
During the RI, various media at the site were analyzed for chlorinated dibenzodioxins ("dioxins") and
dibenzofurans ("furans"). These contaminants form in technical grade PCP during the PCP manufacturing
process. Analytical results were reported in 2,3,7,8-tetrachlorodibenzodioxin ("TCDD") eguivalent factors
("TEF") as follows:
Ground water
Background soil
Subsurface soil
Surface soil
Surface water/sediments
2,3,7,8-TCDD TEF <0.6 ng/1
<0.01 ug/1
<1.0 ug/1
<1.0 ug/1
<0.01 ug/1
The dioxin/furan congeners found in all media were generally the more highly chlorinated (hepta- and octa-)
and less toxic forms. Only a relatively small percentage of the congeners detected were
of the more highly toxic forms (tetra-, penta-, hexa-). The data are consistent with areas where
concentrated waste was disposed (i.e., the land treatment, northeast tank, process, and lagoon
areas). Dioxins/furans were found at relatively high concentrations in the wastes in several of the tanks,
but these tanks were removed from the Site during the most recent removal action and no longer present a
threat.
5.3
Volume of Contaminated Soil and Sediment
Based on the various investigations conducted at the Site as summarized above, it is estimated that there are
approximately 78,000 CY of in place soil and sediment containing contaminants in concentrations exceeding the
cleanup levels established for this Site as set forth in Section 7.0, below. As a result of
excavation, the density of the soil (Tons/CY) decreases, thus increasing the volume. When a swell factor of
1.25 is applied, this volume increases to approximately 97,000 CY of soil and sediment that will reguire
treatment. This swell factor of 1.25 was used by the U.S. Army Corps of Engineers ("Army Corps") in
determining the cost estimates for the excavation alternatives in the FFS. Table 4 lists the various areas
of the Site and the estimated volume of soil/sediment which will be excavated and treated during the remedial
action.
6.0
SUMMARY OF SITE RISKS
A baseline Risk Assessment was prepared in order to identify and define possible existing and future health
risks and potential environmental impacts associated with exposure to the chemicals present in the various
environmental media at the Site if no action were taken. The baseline Risk Assessment provides the basis for

-------
taking action and indicates the exposure pathways that need to be addressed by the remedial action. The
Baseline Risk Assessment can be found in Section 5.0 of the RI Report (May 1988) prepared by CDM Federal
Programs Corporation. In this case the risk assessment is referred to as the "Public Health
Assessment". It was used as one of the bases for the 1988 ROD for the Site and has not been changed.

6.1 Contaminants of Concern

During the RI at the Site, 40 organic and 22 inorganic chemicals were detected in the surface water,
sediments, soils, and ground water. To simplify the risk assessment, these chemicals were screened so that
only those chemicals most likely to contribute to the risk were evaluated in detail. Table 2 lists chemicals
detected in all Site media with the exception of the chlorinated dioxins/furans. Table 5 lists the chemicals
of concern ("COCs") selected for the Site. Because the inorganic chemicals do not appear to be present above
the background levels and inorganic chemicals are not associated with the wood treating activities at the
Site, no inorganics were selected as COCs.

Dioxins/furans were dropped from consideration as COCs most likely because concentrations in Site media did
not exceed the action levels that would have triggered a concern for these compounds at the Site (1 ug/kg TEF
for residential soil, and 0.01 ug/1 TEF for ground water)* Furthermore, they would not have
contributed significantly to the risk relative to the other contaminants at the Site because of their low
concentrations.

The Site is currently vacant and is completely fenced. No wood treating activities are conducted onsite and
no one uses it as a residence. Some drinking water supply wells in the area use the shallow aguifer as their
water source. However, no drinking water wells are located onsite presently and the major
contaminant plume is contained within the sheet pile wall. The cleanup levels established for this Site were
developed assuming that the Site would be used for residential purposes, including use of ground water in the
shallow aguifer, following remediation.

6.2 Human Health Risk Assessment

6.2.1 Exposure Assessment

The objective of the exposure assessment is to estimate the type and magnitude of exposures to the COCs that
are present at or migrating from a site and the amount of each chemical of potential concern at a site that
is actually taken into the body (i.e., the intake level or dose). The results of the exposure
assessment are combined with chemical-specific toxicity information to characterize potential risks.

6.2.1.1 Exposure Pathways

A complete exposure pathway consists of the following elements: (1) a chemical source or a mechanism for
contaminants to be released into the environment; (2) a medium through which contaminants may be transported,
such as water, soil, air; (3) a point of actual or potential contact with contaminants (exposure point); and
(4) a route or mechanism of exposure, such as ingestion, inhalation, or dermal contact, at the exposure
point.

Exposure scenarios for both current-use and future-use conditions were considered for soil, sediment, ground
water, surface water, and air. A summary of exposure pathways that were evaluated in detail is as follows:

! Current-use - direct contact with and ingestion of sediment
and soils by trespassers and ingestion of contaminated fish
from the off-site pond

! Future-use - Direct contact with and ingestion of soil by
construction workers and future residents and ingestion of
contaminated ground water from the shallow and deep aguifers
by future residents.

-------
Current-use scenarios were not evaluated for residents since no one currently lives onsite. Carcinogenic
chemicals of concern, expected to drive the risk levels, though not detected in surface water, were evaluated
for bio-uptake in fish using a surface water exposure model. Air contamination was not considered an
exposure route because no contaminants were detected during air sampling during the RI and the chemicals in
the Site soils are of low volatility. Future-use scenarios for sediments were not
included because it was assumed that during development of the Site the pond sediments would be mixed with
area soils during excavation and remediation operations.

Based on the assumptions made in the risk assessment that the Site might be developed for residential use in
the future, the future-use scenarios included direct contact with contaminated soil and use of ground water
as a potable water supply. Utilizing shallow ground water for drinking water, while unlikely, is considered a
possibility since local residents use the shallow ground water upgradient from the Site. It is more probable
that the deep aguifer will be used for a drinking water source. The deep ground water scenario assumed that
contaminants present in the shallow aguifer will migrate to the deep ground water aguifer used as a potable
water supply.

6.2.1.2 Estimation of Exposure Point Concentrations

In order to assess risk, concentrations of COCs in various media were estimated. Estimating exposure point
concentrations was accomplished in two ways; (1) by using the RI data to calculate direct exposure, and (2)
by utilizing a transport model to predict the potential migration of contaminants and subseguent
concentration at the exposure points. Table 6 lists site media and corresponding concentrations of COCs
(from the RI) used in the risk assessment.

The current and future exposure scenarios examined for the Site, involving direct contact with soils and
sediments and future use of onsite ground water, used the data from the RI directly.

Modeling was used to develop exposure point concentrations for the following exposure scenarios:

! Human health risk through ingestion of aguatic life.

! Potential adverse effects on aguatic life in nearby surface water bodies.

! Potential future human health risks through ingestion of
ground water contaminated by infiltration of contaminated soil.

! Potential future human health risk through ingestion of
ground water contaminated by permeation of the clay barrier
between the shallow and deep aguifers.

SURFACE WATER EXPOSURE MODEL - The purpose of the surface water exposure model was to predict an annual
average concentration of COCs in the pond approximately one mile downstream of the Site. This prediction was
then used to assess the potential impact on aguatic life and the potential risk of ingesting fish caught from
the pond. At the SMWT Site, surface runoff and ground water discharge contribute to the dissolved
concentrations of contaminants in the stream. Soil erosion contributes to the suspended portion of the
surface water concentrations.

The model calculated loading rates that describe the mass of surface runoff, ground water recharge, and soil
mass eroding from the Site. The loading rates were then multiplied by the concentrations of contaminants
detected in soil and ground water to estimate the proportion of contaminants in the loading. The model
relates soil concentrations to surface water concentrations.

Because exposure modeling involves a number of uncertainties, it was appropriate to use a range of
concentrations for the risk assessment. The geometric mean concentrations of COCs detected in soil and
ground water were used to develop the average case value, and the maximum values detected were used to
develop the plausible maximum case. Table 7 lists the estimated annual surface water concentrations for the
offsite pond.

-------
GROUND WATER CONTAMINANT TRANSPORT MODEL - INFILTRATION - RI data showed contamination of surface and
subsurface soil at the SMWT Site. Over time, a portion of the soil contaminants may become dissolved during
infiltration and contaminate the shallow aquifer as the contaminated leachate infiltrates to ground water.
In order to determine future contaminant concentrations due to this leaching, a two-part transport model was
derived. In part one, the contaminant concentration in the infiltrate was determined by assuming an
equilibrium partitioning between the soil and water. In part two, a dilution equation was used to estimate
the mixing of the infiltrate with the water table aquifer beneath the Site. The model does not account for
biodegradation and therefore provides a conservative estimate of contaminant concentrations.
Table 7 lists the average and maximum plausible groundwater concentrations predicted by the model.

GROUND WATER CONTAMINANT TRANSPORT MODEL - PERMEATION - During the RI, ground water from the deeper aquifer
did not reveal contamination. To assess potential future migration of chemicals through the clay layer, a
one dimensional, vertical, downward transport model was used to predict concentrations over time from 1 to
100 years. Average and maximum values of contaminants detected in the shallow aquifer were used to provide
initial source concentrations for average and plausible maximum case estimates. The model assumes uniform,
steady, vertical, downward flow and first order decay, and linear, equilibrium adsorption of the contaminants
in the aquifer. The model does not account for biodegradation and may result in an overestimation of the
concentrations of the contaminants. For the COCs at the SMWT Site, the concentrations predicted by the model
for up to 100 years were below detection due to the integrity of the clay layer. Thus, CPAHs and benzene are
unlikely to contaminate the deep aquifer through permeation of the clay layer in any detectable concentration
within any reasonable time period (i.e., at least the next 100 years).

6.2.1.3 Populations at Risk and Exposure Estimates

This step of the risk assessment involved examining the exposed or potentially exposed populations (e.g.,
current trespassers, future residents or construction workers) and determining their potential levels of
exposure. This involved making assumptions about their behavior that might determine the amount of
contamination to which they would be exposed.

Two cases for the intake of contamination were considered for exposed populations, an average case and a
plausible maximum case. The average case assumes average estimates of exposure parameters (e.g., average
frequency and duration of exposure) and uses the geometric mean concentration of contaminants found in
each media. The plausible maximum case assumes the highest estimates of the exposure parameters and uses the
maximum concentrations of contaminants found in each media.

Exposure of Trespassers to Contaminated Soil and Sediments - Under this scenario it is assumed that
trespassers will enter the property and come into contact with contaminated soil. Contaminants will then be
absorbed through the skin or ingested by eating or smoking with dirty hands. Trespassers are assumed
to be between 13 and 18 years of age and have an average lifetime body weight of 60 kg. Additional
assumptions used to estimate exposure are listed in Table 9. The same assumptions were used for exposure to
sediments.

Exposure of Future Construction Workers to Contaminated Soil - Future construction workers on the Site would
likely contact contaminated soil and absorb contaminants through the skin or by ingestion from the hands.
Construction workers are assumed to be adults who weigh 70 kg and work 5 days a week and work 3-6 months
onsite. Table 10 lists additional assumptions used to estimate exposure.

Exposure of Future Residents to Contaminated Soils - Under this scenario, if residential development took
place onsite, future residents might be exposed to contaminated soils. Several different age groups, as well
as residents living onsite for the average lifetime of 70 years, were evaluated using different
assumptions about how each would be exposed to contaminants in site soils. Children were considered the most
likely to be at risk because their daily intake of soil is quite high relative to older age groups. Table 11
lists the assumptions used to estimate exposure for each age group.

Besides soil ingestion, residents might become exposed to contaminants through dermal absorption by direct
contact with soils. The surface area of exposed skin for children was assumed to be hands, lower arms, lower

-------
legs, and for adults, hands and forearms only. To calculate the exposure parameters for a lifetime resident,
the values for the different age groups were averaged taking into consideration the length of time the person
spends in that group.

Exposure of Future Residents to Contaminated Ground Water - The Site could be used for residential purposes
in the future with the possibility of residents using ground water in the vicinity of the Site as a drinking
water supply. The assumptions used for this scenario were that a 60 kg individual would ingest two liters of
contaminated water per day for 70 years.

6.2.2 Toxicity Assessment

A toxicity evaluation of the contaminants present at the Site was conducted in order to identify carcinogenic
potency factors and chronic reference doses against which daily intake levels could be compared. Table 8
lists these health effects criteria used for evaluating the risks associated with exposure to the COCs at the
Site.

Cancer potency factors ("CPFs") have been developed by EPA's Carcinogenic Assessment Group for estimating
excess lifetime cancer risks associated with exposure to potentially carcinogenic chemicals. CPFs, which are
expressed in units of (mg/kg-day)-1, are multiplied by the estimated intake of a potential carcinogen,
in mg/kg-day, to provide an upper-bound estimate of the excess lifetime cancer risk associated with exposure
at that intake level. The term "upper bound" reflects the conservative estimate of the risks calculated from
the CPF. Use of this approach makes underestimation of the actual cancer risk highly unlikely. Cancer
potency factors are derived from the results of human epidemiological studies or chronic animal bioassays to
which animal-to-human extrapolation and uncertainty factors have been applied.

Reference doses ("RfDs") have been developed by EPA for indicating the potential for adverse health effects
from exposure to chemicals exhibiting noncarcinogenic effects. RfDs, which are expressed in units of
mg/kg-day, are estimates of lifetime daily exposure levels for humans, including sensitive individuals, that
are likely to be without an appreciable risk of adverse health effects. Estimated intakes of chemicals from
environmental media (e.g., the amount of a chemical ingested from contaminated drinking water) can be
compared to the RfD. RfDs are derived from human epidemiological studies or animal studies to which
uncertainty factors have been applied (e.g., to account for the use of animal data to predict effects on
humans). These uncertainty factors help ensure that the RfDs will not underestimate the potential for
adverse noncarcinogenic effects to occur.

Among the many contaminants found at the Site in the various media, the PAHs were found in the highest
concentrations and with the most frequency. PAHs are a complex class of chemicals consisting of two or more
fused aromatic rings with widely varying toxic potencies. Though carcinogenicity is the toxic
effect of greatest public health concern, PAHs have also been shown to cause cytotoxicity in rapidly
proliferating cells throughout the body, immunosuppresive effects, and dermal toxicity.

For practical purposes, the PAHs are often separated into two categories, the carcinogenic PAHs and the
noncarcinogenic PAHs. The approach adopted by the risk assessment for the SMWT Site was to apply the
carcinogenic potency factor (11.5 (mg/kg/day)-1) calculated from assays on benzo(a)pyrene ("BAP") to the
entire subclass of CPAHs. This assumes that all CPAHS have the same potency as BAP. BAP is classified as a
Group B2 Probable Human Carcinogen based on inadequate evidence of carcinogenicity in human studies and
adequate evidence in animal studies. This is likely to result in overestimates of risk for two reasons:
first, BAP is considered to be one of the most potent carcinogenic PAHs; and second, BAP constitutes only a
small fraction of the total PAHs present at the Site. PAHs have demonstrated carcinogenic effects through
the oral, inhalation, and dermal pathways.

In assessing the effects of the noncarcinogenic PAHs, the reference dose for naphthalene (0.41 mg/kg/day) was
applied to the noncarcinogenic PAHs because the toxicity data appeared to be the most adequate and available
for this class of compounds.

6.2.3 Risk Characterization

-------
In the risk characterization step, the toxicity and exposure assessments are summarized and integrated into
quantitative and qualitative expressions of risk. There are several differences between the approach used to
describe risk for carcinoqens and noncarcinoqens. Both approaches are summarized below.

6.2.3.1 Carcinoqenic Risk

For carcinoqens, risks are estimated as the upper bound of the incremental probability of an individual
developinq cancer over a lifetime as a result of exposure to the carcinoqens. Excess lifetime cancer risks
are determined by multiplyinq the dose or chronic daily intake ("GDI") with the cancer potency factor. GDIs
are calculated usinq the concentrations of contaminants present in Site media and the exposure assumptions
discussed in Section 6.2.1, above.

Carcinoqenic risk estimates for each chemical and each exposure pathway may be added toqether to determine
the aqqreqate risk associated with exposure to multiple contaminants in multiple media. These risks are
probabilities that are qenerally expressed in scientific notation (e.g., 1 x 10-6 or 1E-6) . An excess
lifetime cancer risk of 1 x 10-6 indicates that, as a plausible upper bound, an individual has a one in one
million chance of developinq cancer as a result of site-related exposure to a carcinoqen over a 70-year
lifetime under the specific exposure conditions at a site. EPA's tarqet Carcinoqenic risk ranqe is 1 x 10-6
to 1 x 10-4 (i.e., one in one million to one in ten thousand).

The carcinoqens evaluated for the SMWT Site included the CPAHs and benzene because these are the carcinoqens
that contribute the majority of the risk. The Carcinoqenic risks calculated for each
potentially exposed population for each medium are presented in Table 12.

Averaqe and maximum upper bound excess lifetime cancer risks of 5 x 10-9 and 6 x 10-5 associated with the
exposure of trespassers to the CPAHs in site soils were calculated. Cancer risks of 3.4 x 10-9 and 6.6 x
10-7 were calculated for exposure to sediments under the averaqe and plausible maximum exposure conditions,
respectively. For future construction workers, averaqe and plausible maximum cancer risks were 3 x 10-8 and
3 x 10-4, respectively, due to exposure to both surface and subsurface soil. The maximum case risks for
construction workers exceeded the upper end of EPA's tarqet risk ranqe. All risks calculated for trespassers
were within the tarqet risk ranqe.

Future onsite residents are likely to be exposed mainly to surface soil. Cancer risks are qreatest for
children 1-6 years of aqe (2 x 10-6 averaqe case and 2 x 10-2 plausible maximum case) and residents who live
in the area for a lifetime (2 x 10-6 averaqe case and 2 x 10-2 plausible maximum case); however,
siqnificant risks are also associated with all aqes under the plausible maximum exposure scenario. Risks are
in the ranqe of 1 x 10-2 to 2 x 10-2 and exceed the upper bound of the tarqet risk ranqe.

Risks from inqestion of qround water for future onsite residents were calculated usinq actual current qround
water data and the infiltration model discussed previously. Both are presented in Table 12. Risks
calculated usinq actual current qround water data for CPAHs were 3 x 10-2 and 0.95, respectively, for the
averaqe and maximum exposure cases. Predicted qround water risks in the shallow aquifer from the modelinq
data were 3.5 x 10-6 and 2 x 10-3, respectively, for the averaqe and maximum exposure cases. The assessment
of risk from qround water did not include exposure to contaminated qround water by routes other than
inqestion. Nevertheless, risks from inqestion alone associated with exposure to contaminated qround water
exceed the upper bound of the tarqet risk ranqe.

6.2.3.2 Noncarcinoqenic Risks

Potential concern for noncarcinoqenic effects of a sinqle contaminant in a sinqle medium is expressed as the
hazard quotient ("HQ") (or the ratio of the estimated intake derived from the contaminant concentration in a
qiven medium to the contaminant's reference dose). By addinq the HQs for all contaminants within a medium or
across all media to which a qiven population may reasonably be exposed, the Hazard Index ("HI") can be
qenerated. The HI provides a useful reference point for qauqinq the potential siqnificance of multiple
contaminant exposures within a sinqle medium or across media. HI values less than or equal to 1.0 indicate
that lifetime exposure has limited potential for causinq an adverse effect in sensitive populations. HI
values qreater than 1.0 show that acceptable levels of intake

-------
have been exceeded.

Contaminants that were included in the noncarcinogenic risk calculations included the non-CPAHs, PCP, BTEX
compounds, and several other phenolic compounds. Table 13 presents the noncarcinogenic risks associated with
the various populations and exposure pathways developed for the Site.

Noncarcinogenic risks with HI values well below 1.0 were calculated for trespassers (soil and sediments),
construction workers (soils) and residents exposed to soils under both average and plausible maximum cases.
The HI value for noncarcinogenic risk to residents from ground water under the average case
scenario was 1 x 10-1. The only exceedence of the HI value of 1.0 was seen in the plausible maximum
residential ground water exposure scenario where the HI value was 50.

6.3 Environmental Risks

A formal guantitative ecological risk assessment was not generated for the SMWT Site during the RI; however,
EPA reguested that the U.S. Fish and Wildlife Service ("FWS") conduct an investigation to document impacts of
the Site on aguatic biota. The results of the investigation are summarized below and can be found in the
report Biota Investigation of Freshwater Streams Possibly Affected by Southern Maryland Woodtreating
Superfund Site (U.S. FWS, April 1990).

At the eight locations depicted in Figure 9, water guality parameters and physical conditions were recorded
and fish populations were observed by electroshocking. Benthic invertebrates were collected, identified, and
results were analyzed using EPA Rapid Bioassessment Protocols. A total of 2.39 acres of wetlands were
delineated within the SMWT property boundary and are shown in Figure 10.

6.3.1 Contaminants of Concern

The contaminants of concern established by the FWS were PAHs, PCP and other organic compounds. PCP was
detected well above water guality criteria for the protection of aguatic resources in the onsite pond and the
upper reaches of the west tributary closest to the pond. PCP found in the sediments may result in a biota
exposure problem. Further downstream, PCP was not detected.

The two and three-ring PAHs were not considered to be especially problematic because they are fairly mobile
and photodegrade rapidly in water. The larger four to seven-ring PAHs, however, tend to associate with
sediment where they degrade slowly and can be bioaccumulated by invertebrates. As no wildlife protection
criteria exist for PAHs, the drinking water criteria were used for comparison to Site contaminant levels.
Concentrations of PAHs in the onsite pond and upper reaches of the west tributary
were found to be well above the drinking water criteria. FWS stated that the toxicity of the larger PAH
molecules was likely to be chronic and persistent until contaminated sediment was buried or otherwise made
unavailable to biota.

6.3.2 Terrestrial Routes of Exposure

Terrestrial animals would most likely be exposed to contaminants from soil, surface water, or through the
food chain. The perimeter fence should keep large animals offsite but evidence of deer onsite was observed
due to breaks in the fence that were present at the time. Smaller animals such as rabbits likely use the
Site. Animals that live close to the ground, such as mice, and snakes would likely be exposed to soil
contamination. Terrestrial animals may also be exposed to contaminants from the surface water and the pond
which creates an attractive nuisance for wildlife.

6.3.3 Aguatic Routes of Exposure

Aguatic animals may be exposed to waterborne contaminants through dermal exposure, respiration (gills), or
through the food chain. Rainwater runoff, as well as ground water discharge, may introduce contaminants into
surface water. Exposure is likely to be chronic as contaminants have likely been entering the west
tributary for years and are likely to continue until remediation of the Site is completed.

-------
6.3.4 Effects On Stream Ecosystems

Aquatic biota were impacted in the west tributary relative to reference sites, but the presence of frogs and
the diversity and relatively high density of benthie invertebrates indicate that negative effects of Site
contamination are somewhat limited. Benthie invertebrate populations were slightly to moderately
impacted, mainly due to the absence of pollution intolerant groups. No fish were observed in the upper
reaches of the tributary adjacent to the Site. This may or may not be a result of Site contamination. Fish
populations upstream and downstream of the confluence with the west tributary did not indicate
impacts from the Site to Brooks Run or Mclntosh Run.

6.4 Conclusion

Based on the baseline risk assessment discussed above, EPA concluded that actual or threatened releases of
hazardous substances from the Site, if not addressed by implementing the response action selected in the 1988
ROD, might present an imminent and substantial endangerment to public health, welfare, or the environment.

When EPA commenced the FFS in 1992, essentially all the contamination that had been onsite when the baseline
risk assessment was conducted remained onsite; hence, EPA concluded that it was not necessary to recalculate
the risk posed by the Site if it were not remediated. It was assumed that the Site still required action to
address the contaminants in various media. Because onsite tanks, drums, and several buildings and their
contents have since been removed from the Site, any risk formerly posed by these sources has been mitigated.
However, the long term risk posed by NAPLs, soil, ground water, surface water
and sediment contamination remains to be addressed.

EPA performed a Focused Post-Remediation Risk Assessment ("FRA") that evaluated the human health risks during
and post-remediationfor each of the nine alternatives developed in the FFS. See Focused Human Health Risk
Assessment, Risks After Remediation for Nine Remedial Alternatives for the Southern Maryland Wood Treatment
Site, Roy L. Smith, Ph.D, US EPA, November 17, 1994. Section 8.0, below, discusses the FRA in more detail.

7.0 REMEDIAL OBJECTIVES AND CLEANUP LEVELS

In order to address the unacceptable risks discussed in Section 6.0, above, and to protect human health and
the environment, the following remedial action objectives and associated cleanup levels have been
established:

(1) to prevent ingestion/direct contact with surface soils that contain in excess of 0.1 ppm benzo(a)pyrene
(B(a)P) equivalence!;

(2) to protect ground water as a current or potential drinking water supply, by containing or treating
subsurface soil that contains in excess of 1.0 ppm B(a)P equivalence2;

1 The contaminants that present the greatest risk at the Site are the CPAHs. The cleanup Levels set
forth in this ROD were therefore based on addressing these contaminants. EPA believes that the
distribution of different PAH compounds assumed in the Focused Risk Assesssent is statistically valid,
and that individual lots of soil srs unlikely to differ greatly from the everage proportions observed.
However, the Agency acknowledges that it is at Least theoretically possible that significant
deviations could occur, and that some more highly toxic compounds Like benzo[a]pyrene might be present
at proportions higher than expected. To avoid this problem, EPA has set cleanup standards in terms of
benzo[a]pyrene (8[a]P) equivalence. This approach involves converting all CPAH concentrations to
(B[a]P) equivalence, using a set of factors which are based on the relative carcinogenic potency of
each compound (See Table 17). B[a]P equivalence for all CPAHs is then summed for comparison with the
cleanup standard.

EPA believes that setting a cleanup level (i.e., to determine both limits of excavation and acceptable CPAH
concentrations in treated soil) based on 8[a]P equivalence is reasonable for the Southern Maryland site. EPA
emphasizes that although ppm of CPAH can be converted to and expressed in terms of some lower number of ppm
8[a]P equivalence, the actual risks posed by the contaminants are exactly the same.

-------
Carcinogenic PAHs included in calculations to determine the cleanup levels include benzo(a)pyrene,
benzo(b)fluoranthene, benzo(k)fluoranthene, benz(s)anthracene, carbazole, and chrysene.  Any additional CPAHs
that might be encountered during remediation, such as indeno(1,2,3-cd)pyrene or dibenzo(a,h)anthracene, can
be converted to B(a)P eguivalence and factored into the total 8(a)P eguivalence to assure that cleanup levels
have been achieved.

     2 The 1.0 ppm B(a)P eguivalence cleanup level was developed from the 10 ppm CPAH cleanup level.
       The 10 ppm CPAH cleanup level for subaarface soil was originally selected at the start of the FFS as a
       screening level to evaluate renedial technologies.   On an engineering basis, EPA believed that the
       list of technologies developed for evaluation in the FFS Work Plan could more reasonably achieve a
       cleanup level of 10 ppm CPAHs than the 1 ppm CPAHs cleanup level selected in the original Record of
       Decision (ROD), that this level could be implemented at a reasonable cost,  and that it would result in
       an acceptable post-remedial risk. The Focused Risk Assessment then confirmed that on a risk basis this
       assumption was correct; therefore, the 10 ppm CPAH was determined to be an acceptable subsurface soil
       cleanup number.

In order to calculate the risks to ground water in the Focused Risk Assessment, EPA conducted a modeling
exercise which is documented in Soil Cleanup Goals Modeling Using Multimedia Exposure Assessment  (MULTIMED)
Model Version 1.01  (Analytical) & Version 2.0  (Analytical & Numerical), David M. Kargbo, Ph.D., U.S. EPA
Region 30 October 1994.  MULTIMED was used to calculate the dilution attenuation factors  (DAF) for each
contaminant  (MULTIMED Report, Table 6).   The DAFs were then used to calculate the ground Water
concentrationsthat would result from leaving 10 ppm CPAHs in the onsite soil  (Focused Risk Assessment,
Appendix 2, Table 1).

(3)  to prevent future ground water contamination through the recovery and/or management of NAPL; and

(4)  to protect surface water guality and to restore sediments in the pond and tributaries to acceptable
levels for the protection of aguatic life.  Sediment cleanup levels have been set at 3.2 ppm low molecular
weight PAHs, and at  9.6 ppm high molecular weight PAHs3 and 0.4 ppm PCP4.  All sediment cleanup levels are
on a dry weight basis.

Further, upon achievement of the cleanup levels as defined herein, the Site will be available for residential
use.

8.0     DESCRIPTION  OF ALTERNATIVES

The FFS evaluated nine remedial alternatives to address the risks posed by current and potential future
exposure to contaminants at the SMWT Site.  The alternatives include:

   1)  No Further Action
   2)  Limited Action and monitoring
   3)  Capping and containment
   4)  Excavation, capping and containment
   5)  Excavation and offsite disposal
   6)  Excavation and onsite thermal treatment  (incineration)
   7)  Excavation and onsite thermal desorption
   8)  Excavation and onsite solid-phase bioremediation
   9)  Excavation and onsite slurry-phase bioremediation

COMMON ELEMENTS:

Monitoring:  All alternatives include ground water, surface water and sediment monitoring, although the
duration of the monitoring program varies from alternative to alternative.  For alternatives that leave a
significant portion  of the contaminated material onsite (Alternatives 1-4), the monitoring period would
continue

The resulting ground water concentrations were then used to calculate the risks to ground water which are

-------
presented in the Focused Risk Assessment in Tables 50 and 51 and in this ROD in Tables 14 and 15.

3 For sediment cleanup levels, low molecular weight PAHs include, but are not limited to,
acenaphthene, acenaphthytene, anthracene, fluorene, 2-methyl naphthalene, naphthalene, and
phenanthrene. High molecular weight PAHs include, but are not limited to, benz(a)anthracene,
benzo(a)pyrene, chrysene, dibenzo(a,h)anthracene, fluoranthene, pyrene. Sediment cleanup levels are
based on sediment screening guidelines found in the document National Status and Trends Program
Approach. In: Sediment Classification Methods Compendium. Long, E.R. D.D. Mac Donald, 1992, EPA
823-R-92-006. EPA Office of Water (WH-556). Washingten, D.C.

4 The PCP cleanup level provided by the FWS is based on Sediment Quality Values Refinement:
Volume I, 1988 Update and Evaluation of Puget Sound AET, U.S. EPA, September 1988.

for thirty years. For alternatives that include the treatment or offsite disposal of contaminated material
(Alternatives 5-9), the monitoring period would include the time reguired for the remedial action to take
place and a short period thereafter. Following soil and sediment remediation, monitoring would
continue until EPA, in consultation with MDE, confirmed that Resource Conservation and Recovery Act ("RCRA")
clean closure reguirements have been met, MCLs or other risk-based chemical-specific ARARs had been met in
the ground water and that surface water guality criteria had been met in the surface water. During this
post-remediation monitoring period in Alternatives 5-9, institutional controls temporarily restricting ground
water use in the shallow aguifer would be implemented and maintained.

DNAPL: The DNAPL is addressed differently by the various alternatives. The No Further Action and limited
Action alternatives (Alternatives 1 and 2) do not address the DNAPL. In Alternatives 3 and 4, the possible
recovery of the DNAPL would be evaluated during the remedial design. Recovery might be accomplished by
operation of the existing trench, an enhancement of the system, or by installation of extraction wells.
Alternatives 5 through 9 address DNAPL through active collection during the excavation of contaminated soil
in the containment area and soil dewatering where it will be separated from the
ground water. In all alternatives that address DNAPL, all collected DNAPL would be shipped offsite for
treatment and disposal.

Ground water: Ground water within the containment area would be collected and treated in the onsite water
treatment system under all but the No Further Action and limited Action alternatives. In the capping
alternatives, if it were determined during the remedial design that DNAPL recovery is possible, ground water
might be collected in the trench or recovery wells and would also be treated in the onsite water treatment
system. For Alternatives 5-9, ground water within the containment area would be collected during soil
excavation and dewatering, treated in the onsite water treatment system, and discharged to the west
tributary.

Surface Water: Surface water in the onsite pond would be pumped and treated in the limited action
alternative (Alternative 2) on a long-term basis (30 years) to prevent contaminated surface water from
leaving the Site via the west tributary. In Alternatives 3-9, surface water in the onsite pond and
tributaries would be addressed through the treatment or containment of contaminated soils, sediments, and
ground water. In Alternatives 3-9 the pumping and treating of surface water from the pond that was initiated
as a component of the most recent removal action would continue until the remedial action
made it no longer necessary (i.e., until the soils/sediments and ground water that provide a source of
contamination to the surface water were contained or excavated and treated). It is possible that the onsite
pond will be eliminated during the implementation of Alternatives 3-9.

Sheet Pile Wall: The sheet pile wall would remain intact below ground surface in all alternatives.
Following remediation in Alternatives 5 through 9, the sheet piling would be cut off below ground surface but
would not be completely removed to depth.

Perimeter Fencing: In all but the no further action alternative, the perimeter fencing with locking gates
that currently surrounds the Site, would be maintained in a manner sufficient to prevent unauthorized access
to the Site. In Alternatives 2-4, the fence would be maintained for 30 years. In Alternatives 5-9 the fence

-------
would be maintained until such time as EPA determined that all soil cleanup levels had been achieved and that
exposure to Site media would not result in unacceptable risk to human health or the environment.

Building Demolition: In Alternatives 3-9, any onsite buildings that are not necessary for remedial action or
operation and maintenance activities and that are contaminated with hazardous substances above health-based
levels, would either be decontaminated or demolished and the rubble shipped offsite for
treatment and disposal.

In addition to the Common Elements described above, the following is a brief description of the alternatives
which were evaluated for remediation of the Site. All costs and implementation time
frames are estimates and should be used for comparative purposes only. Cost figures include capital costs,
annual operation and maintenance (O&M) costs, and present worth costs for each alternative. The present
worth cost analysis was performed for annual O&M costs for each alternative using a seven percent
discount rate.

Alternative 1 - No Further Action

Estimated Capital Costs: $0
Estimated Annual O&M Costs: $270,000
Estimated Present-Worth Costs: $3,400,000

The NCP reguires that EPA consider a no action alternative for every site to establish a baseline for
comparison to alternatives that do reguire action. No further remedial measures would be implemented under
this alternative. Operation of the existing water treatment facility would cease. Ground water would
continue to flow through contaminated soil. Contaminated ground water and NAPLs would enter the onsite pond
and contaminated surface water would eventually discharge to the west tributary. Contaminated surface soils
would remain onsite, allowing for possible human and wildlife exposure to contaminants. Ground water,
surface water and sediments would be sampled periodically to monitor the potential for offsite migration of
contamination. There are no applicable or relevant and appropriate reguirements
(ARARs) associated with the no further action alternative because by definition, ARARs only apply to remedial
actions selected by EPA (CERCLA Section 121(d) (2)).

Alternative 2 - Limited Action and Monitoring

Estimated Capital Costs: $47,000
Estimated Annual O&M Costs: $320,000
Estimated Present-Worth Costs: $4,047,000

In this alternative no remedial actions would be performed except for the continued pumping and treating of
surface water initiated during the most recent removal action to prevent offsite migration of contaminants
from the onsite pond. Treated water would be discharged to the west tributary. Existing fence security on
the Site would be upgraded, and ground water, surface water and sediment would be monitored. Well housings
around existing monitoring wells would be installed to limit access.

Access to the Site would be restricted by the Site fence, and institutional controls would be implemented to
limit future use of the Site. This could be accomplished by recording in the property deed information
regarding the locations and guantities of hazardous materials disposed of on the property. Since subsurface
contamination is of significant concern, such access restrictions would preclude any intrusive activities,
such as boring or excavating, that would disturb the subsurface soil, or facilitate the migration of
contaminants to new areas.

See "ARARS Common Among Alternatives," below, for further discussion of ARARs relating to this alternative.

Alternative 3 - Capping and Containment

Estimated Capital Costs: $13,000,000
Estimated Annual O&M Costs: $320,000

-------
Estimated Present-Worth Costs: $17,000,000

To prevent human and wildlife contact with contaminated soil, Alternative 3 involves the construction of a
RCRA cap over all areas of soil within the existing Site fence contaminated above the cleanup level of 0.1
ppm B(a)P equivalents. The cap would also prevent or minimize future ground water contamination or
movement of existing ground water contamination by minimizing the infiltration of rain water into the soil.
The process of capping the entire Site, approximately 23 acres, would take an estimated 18 months.

In addition, Alternative 3 includes dredging of any sediments in the tributaries and excavating any soil
located outside the Site fence that are above the cleanup level. These soils and sediments would be
consolidated under the cap within the Site fence. Excavated areas would then be backfilled with clean fill
and regraded. Institutional controls would be implemented to ensure the integrity of the cap and monitoring
structures and to prevent ground water use in the shallow aguifer.

The clay layer underlying the shallow aguifer would prevent the downward migration of contaminated ground
water and DNAPL. During the remedial design, the possible recovery of the DNAPL would be evaluated. This
might be accomplished by continued operation of the existing trench, an enhancement of this system,
or possibly by installation of extraction wells. Any DNAPL collected would be stored onsite temporarily in
preparation for shipment offsite for treatment and disposal. Any ground water collected in the process of
DNAPL recovery would be treated onsite and discharged to the west tributary.

See "ARARs Common Among Alternatives," below, for a discussion of ARARs relating to this alternative.

Alternative 4 - Excavation, Capping and Containment

Estimated Capital Costs: $5,000,000
Estimated Annual O&M Costs: $320,000
Estimated Present-Worth Costs: $9,000,000

This alternative is essentially the same as Alternative 3, except that it involves the excavation of soil and
sediment that is above the cleanup levels from outside the existing containment wall, the consolidation of
this material within the wall, and the placement of a RCRA multi-layer cap over the containment area only.
The excavation activities would take approximately two months and the capping of the containment area,
approximately 4 acres, would take approximately six months.

See "ARARs Common Among Alternatives," below, for a discussion of ARARs relating to this alternative.

Alternative 5 - Excavation and Offsite Disposal

Estimated Capital Costs: $178,000,000
Estimated Annual O&M Costs: $320,000
Estimated Present-Worth Costs: $179,300,000

Offsite disposal involves the excavation of approximately 97,000 CY of soils and sediment contaminated above
the cleanup levels and transportation of the material to an approved treatment and disposal facility. The
most extensive excavation would take place within the containment area, where, in some areas, the soil would
have to be excavated to the clay layer. The excavation process would take about four months. The time frame
necessary for the offsite shipment of the soils would be dependent on the
availability of an appropriate treatment facility.

Because this alternative would reguire excavation below the existing water table within the containment area,
this area would have to be dewatered prior to or during excavation. The collected water would be treated
onsite in the existing water treatment facility. NAPL collected during the excavation and
dewatering processes and any treatment residues would be sent offsite for treatment and disposal. Treated
water would be discharged to the west tributary. Residual NAPL (NAPL in the soil pore spaces) would be
excavated and managed with the subsurface soil. Excavated areas would be backfilled with clean fill.

-------
See "ARARs Common Among Alternatives," below, for a discussion of ARARs relating to this alternative.

Alternative 6 - Excavation and Onsite Thermal Treatment
(Incineration)

Estimated Capital Costs: $57,000,000
Estimated Annual O&M Costs: $320,000
Estimated Present-Worth Costs: $58,300,000

Under this alternative, all surface soil, subsurface soil, and sediment containing contamination in excess of
the cleanup levels (approximately 97,000 CY) would be excavated and treated onsite using a mobile thermal
treatment unit (i.e., an incinerator) that would be transported to the Site. The incineration process would
permanently destroy the contaminants. Clean fill would be backfilled below the water table in the
containment area and treated soil would be backfilled above the water table. Excavation would take
approximately four months and the treatment process itself would take about two years, based on the capacity
of the treatment units expected to be available for use.

Because this would reguire excavation below the existing water table within the containment area, this area
would have to be dewatered prior to or during excavation. The collected water would be treated onsite in the
existing water treatment facility. NAPL collected during the excavation and dewatering processes and any
treatment residues would be sent offsite for treatment and disposal. Treated water would be discharged to
the west tributary. Residual NAPL (NAPL in the soil pore spaces) would be
excavated and treated with the subsurface soil.

The operation of the thermal treatment unit would be in compliance with the RCRA regulations for owners and
operators of hazardous waste treatment, storage and disposal facilities, specifically those associated with
operation of an incinerator (Code of Maryland ("COMAR") 26.13.05.15)5. A permit would not be reguired; only
substantive portions of the regulations would have to be met. Air emissions would be in compliance with
Maryland regulations governing air pollutants and air guality for VOCs, visible emissions, particulates and
nuisances (COMAR 26.11.15, 26.11.06.06, and 26.11.06.02,.03, . 08), and with federal air
emissions standards for process vents (40 C.F.R. Part 264, Subpart AA) and eguipment leaks (40 C.F.R. Part
264, Subpart BB). See "ARARs Common Among Alternatives," below, for a further discussion of ARARs relating to
this alternative.

Alternative 7 - Excavation and Thermal Desorption

Estimated Capital Costs: $31,000,000
Estimated Annual O&M Costs: $320,000
Estimated Present Worth Costs: $32,300,000

Under this alternative, all Site surface soil, subsurface soil, and sediments containing contamination in
excess of the cleanup levels, approximately 97,000 CY, would be excavated and treated onsite using thermal
desorption. Rather than destroying the contaminants as in Alternative 6, the thermal desorption process
would separate volatile and semi-volatile contaminants from the excavated soil and sediments by heating them
to the point where the contaminants vaporize. The separated (vaporized) contaminants would then be
recondensed. The recondensed contaminants, the NAPL collected during the excavation and dewatering of soil,
and any grossly contaminated soil/sediments that are not amenable to treatment by thermal desorption (i.e.,
media saturated with DNAPL in excess of the treatment capability of the thermal desorption unit), would be
stored temporarily onsite then shipped offsite for treatment and disposal. Clean fill would be backfilled
below the water table in the containment area and treated soil and sediments would be backfilled above the
water table within and outside the containment area.

Because this would reguire excavation below the existing water table within the containment area, this area
would have to be dewatered prior to or during excavation. The collected water would be treated onsite in the
existing water treatment facility. Water treatment residues would be sent offsite for treatment and disposal.
Treated water would be discharged to the west tributary. Residual NAPL (NAPL in the soil pore spaces) would
be excavated and treated with the subsurface soil.

-------
The operation of the thermal desorption unit would be in compliance with RCRA regulations for owners and
operator; of

5 References to Maryland's authorized RCRA program regulations are included in the ARARs chart at
Table 18 but have not been included in the body of the ROD.

hazardous waste treatment, storage and disposal facilities, specifically those associated with operation of a
thermal treatment device defined as a miscellaneous unit (COMAR 26.13.05.16-1 and 40 CFR Subpart X, Part
264.600-.603). A permit would not be reguired; only substantive portions of the regulations would have to be
met. Air emissions would be in compliance with Maryland regulations governing air pollutants and air guality
for VOCs, visible emissions, particulates and nuisances (COMAR 26.11.15, 26.11.06.06, and
26.11.06.02,.03,.08), and with federal air emissions standards for process vents (40 C.F.R. Part 264, Subpart
AA) and eguipment leaks (40 C.F.R. Part 264, Subpart BB). See "ARARs Common Among Alternatives," below for a
further discussion of ARARs relating to this alternative.

Alternative 8 - Onsite Solid-Phase Bioremediatton

Estimated Capital Cost (5 years/batch): $31,000,000
Estimated Capital Cost (10 years/batch): $42,000,000
Estimated capital Cost (15 Years/batch): $44,000,000

Estimated Annual O&M Costs (5, 10, 15 years): $320,000

Estimated Present Worth Costs (5 Years/batch): $32,300,000
Estimated Present Worth Costs (10 Years/batch): $43,300,000
Estimated Present Worth Costs (15 Years/batch): $45,300,000

In Alternative 8, contaminated soils and sediments, approximately 97,000 CY, would be excavated and treated
onsite by solid-phase bioremediation, the process of using microorganisms to degrade hazardous organic
contaminants into non-hazardous products. This alternative would include the construction of an onsite land
treatment or composting area in which the treatment would be performed. Management of the treatment process
would include watering, tilling and amending as necessary. Clean fill would be
backfilled below the water table in the containment area and treated soil would be backfilled above the water
table. It may be necessary to cover backfilled soil that contains contaminants in excess of the surface soil
cleanup level with two feet of clean fill.

Due to the limited space available at the Site to carry out the composting/land treatment process, the
excavated soils would need to be treated in a batch process. The solid-phase bioremediation treatment
process is predicted to take between 5 and 10 years per batch to reach the established cleanup levels.
Assuming that the volume of soil and sediment to be treated would be excavated in eight batches, the total
time for remediation would range from 40 to 80 years.

Because this alternative would reguire excavation below the existing water table within the containment area,
the soil within this area would have to be dewatered prior to or during excavation. The collected water
would be treated onsite in the existing water treatment facility. NAPL collected during the
excavation and dewatering processes, any treatment residues, and any grossly contaminated soil/sediment not
amendable to treatment by bioremediation would be sent offsite for treatment and disposal. Treated water
would be discharged to the west tributary. Residual NAPL (NAPL in the soil pore spaces) would be
excavated and treated with the subsurface soil.

The operation of the solid-phase bioremediation treatment process would be in compliance with RCRA
regulations for owners and operators of hazardous waste treatment, storage and disposal facilities,
specifically those associated with land treatment units (COMAR 26.13.05.13) . A permit would not be reguired;
only substantive portions of the regulations would have to be met. Air emissions would be in compliance with
Maryland regulations governing air pollutants and air guality for VOCs, visible emissions, particulates and
nuisances (COMAR 26.11.15, 26.11.06.06, and 26.11.06.02,.03,.08). See "ARARs Common Among Alternatives,"
below, for a further discussion of ARARs relating to this alternative.

-------
Alternative 9: Onsite Slurry-Phase Bioremediation

Estimated capital Costs (15 day retention time): $26,000,000
Estimated Capital Costs (35 day retention time): $33,000,000

Estimated Annual O&M Costs: $320,000

Estimated Present Worth Costs (15 day retention): $27,300,000
Estimated Present Worth Costs (35 day retention): $34,300,000

This alternative is like the other treatment alternatives in that it calls for the excavation and onsite
treatment of soil and sediment contaminated above the established cleanup levels, approximately 97,000 CY.
Alternative 9 is most similar to alternative 8, except that the biological treatment would occur in a
slurry-phase, rather than a solid-phase.

Contaminated soil and sediment would be excavated and washed onsite. The washed soil, composed of the large
particle-size soil fraction, would be backfilled onsite above the water table. Clean fill would be backfilled
below the water table in the containment area. The slurry or liguid wash water containing the
fine particle-size soil fraction and containing the bulk of the contaminants, would be treated in a
bioreactor(s) located onsite. Following treatment, the slurry would be dewatered and the soil backfilled
onsite. If necessary, the treated soil would be covered with two feet of clean fill if the contaminants were
in excess of the surface soil cleanup level. Any water generated in the process would be treated in the
onsite water treatment system.

The cost estimates for this alternative were calculated for two slurry retention times (15 days and 35 days).
These periods refer to the time the slurry would be treated in the reactor in order to reach the appropriate
cleanup level. Given 15 day and 35 day retention times, and the use of 155,000 and 434,000 gallon reactors,
respectively, the time reguired for remediation is estimated to be 15 years.

The operation of the slurry-phase bioremediation treatment process would be in compliance with RCRA
regulations for owners and operators of hazardous waste treatment, storage and disposal facilities,
specifically those associated with storage in containers and treatment in tanks (COMAR 26.13.05.09, .10). A
permit would not be reguired; only substantive portions of the regulations would have to be met. Air
emissions would be in compliance with Maryland regulations governing air pollutants and air guality for VOCs,
visible emissions, particulates and nuisances (COMAR 26.11.15, 26.11.06.06, and 26.11.06.02,.03,.08). See
"ARARs Common Among Alternatives," below, for a further discussion of ARARs relating to this alternative.

ARARS Common Among Alternatives

Table 18 includes a complete listing of ARARs pertaining to all alternatives described above. For any onsite
activities, the implementation of any of the alternatives would comply with only substantive reguirements of
the regulations.

Slternatives 2 through 9 - To determine whether soils, sediments and treatment residuals are hazardous
wastes, regulations that define RCRA characteristic and listed wastes would be used (COMAR 26.13.02.01-.14,
and .16-.19 and 40 CFR §261.24 (toxicity characteristic) and §261.31 (F wastes)).

The water treatment plant would be operated in accordance with Maryland water guality certification
regulations (COMAR 26.08.02.10). Clean Water Act National Pollutant Discharge Elimination System (NPDES)
reguirements and Maryland Discharge limitations (COMAR 26.08.01.02, COMAR 26.08.02.03, 33 U.S.C.
§1342 and COMARS 26.08.03.01 and .07, 40 C.F.R. Pare 125 Subpart K, and 40 C.F.R. Part 136) pertaining to
the discharge of treated water to the west tributary would be met. Permits are not reguired for these onsite
CERCLA actions. Any NAPLs collected, any water treatment residuals and any building demolition rubble
determined to be contaminated with hazardous wastes would be staged and managed onsite prior to offsite
shipment for treatment and disposal in accordance with RCRA regulations under Subtitle C.

Installation of monitoring wells would be conducted in compliance with Maryland regulations for well

-------
construction (COMAR 26.04.04). Wells shall be installed by persons certified by the Board of Well Drillers
pursuant to COMAR 26.05.01.

These alternatives would comply with applicable statutory and regulatory requirements under RCRA Subtitle C
relating to Corrective Action of solid waste management units, including 40 C.F.R. Part 264, Subparts F and
S.

Any remedial actions would be implemented in a manner that would not adversely impact any identified
endangered species pursuant to the Endangered Species Act of 1978 (16 U.S.C. §1531 et seg., 50 C.F.R. Part
402) or historic resources pursuant to the Archaeological and Historical Preservation Action of 1974 (16
U.S.C. §469) and the National Historic Preservation Act of 1966, as amended (16 U.S.C. §470 et seg., 36
C.F.R. Part 800).

Alternatives 3 through 9 - Dewatering of excavated soil and sediments will be performed in a manner
consistent with all applicable RCRA treatment and storage requirements in Subtitle C.

Monitoring would be conducted to ensure that groundwater contaminant concentrations do not exceed Safe
Drinking Water Act Maximum Contaminant levels (MCLe) (40 CFR §141.11-.12 and 141.61 - .62), non-zero MCL
Goals (40 CFR §141.50-.51), or other risk-based chemical-specific guidelines (e.g., information found in
the Integrated Risk Information System developed by the EPA Office of Research and Development, EPA Health
Advisories on Drinking Water developed by the EPA Office of Drinking Water, and Health Effects Assessments
developed by the EPA Environmental Criteria and Assessment Office and the Ground Water Protection Strategy of
1984 EPA 440/6-84-002) and that surface water concentrations do not exceed surface water quality criteria for
site-related contaminants (33 U.S.C. §1314 and COMAR 26.08.02.03).

EPA has designated the Site as an Area of Contamination ("AOC") therefore eliminating the need to comply with
RCRA land Disposal Restriction ("LDR") requirements (40 C.F.R. Part 268) for onsite land-based remedial
activities within the AOC.

Dredging of the sediments in the tributaries would be in compliance with the substantive requirements of
Maryland wetlands regulations (COMAR 08.05.04), Clean Water Act dredge and fill requirements (33 U.S.C.
§1344, 40 C.F.R. Part 230), Army Corps regulations (33 CFR Parts 320-330) and the "Procedures for
Implementing the Requirements of the Council on Environmental Quality" with regard to the protection of
wetlands and floodplain management (40 C.F.R. Part 6, Appendix A).

Alternatives 3 and 4 - Cap construction, operation and maintenance, and closure and post-closure of the
capped area would be performed in accordance with RCRA regulations applicable to landfills containing
hazardous waste (COMAR 26.13.05.14 and COMAR 26.13.05.07). Excavation and cap construction would also
be in compliance with Maryland regulations for the control of noise pollution (COMAR 26.02.03.02 A(2) and
B(2) and COMAR 26.02.03.03 A), storm water management (COMAR 26.09.02), and erosion and sediment control
(COMAR 26.09.01.11).

Alternatives 5 through 9 - Excavation and backfilling activities would be in compliance with the substantive
requirements of Maryland regulations for the control of noise pollution (COMAR 26.02.03.02 A(2) and B(2) and
COMAR 26.02.03.03 A), storm water management (COMAR 26.09.02), and erosion and
sediment control (COMAR 26.09.01.11). In preparation for treatment (Alternatives 6-9) or offsite disposal
(Alternative 5) and in preparation for backfilling after treatment (Alternatives 6-9), excavated soils and
sediments would be staged and managed onsite in accordance with RCRA regulations under Subtitle C.

EPA and MDE anticipate that the implementation of Alternatives 5-9 would meet the RCRA clean closure
requirements for the former landfill areas (i.e., the land treatment area and the containment area) (COMAR
26.13.05.07 and COMAR 26.13.05.14).

Alternatives 6 through 9 - Ground water appropriation for use in the treatment processes would be approved in
accordance with COMAR 08.05.02. Any NAPLs collected during excavation and dewatering, any grossly
contaminated soils or sediments that are not capable of being treated, and any treatment residuals
determined to be contaminated with hazardous wastes would be managed prior to offsite shipment for treatment

-------
and disposal in accordance with RCRA regulations Subtitle C.

Delisting of RCRA Hazardous Wastes

Alternatives 6 through 9 - The soils to be treated under these alternatives are contaminated with wood
preserving waste identified and listed as K001 under both EPA's and Maryland's hazardous waste regulations,
and F032 and F034 under EPA's hazardous waste regulations. Although the soil is contaminated
with listed constituents, MDE and EPA do not view the soil itself as a hazardous waste. The soil is
considered a natural media that must be managed as a hazardous waste due to the presence of the listed
constituents. After treatment by the selected remedy has been completed, it must be demonstrated that the
concentration of constituents remaining in the soil are reduced to the point that the soil no longer presents
a threat to human health and the environment and, therefore, no longer reguires management as a hazardous
waste.

As more fully explained in the FFS (See Section 3.2.6.2', EPA determines when contaminated media no longer
reguires management as a hazardous waste pursuant to EPA's "contained-in" policy. However, Maryland has taken
the position that EPA' s contained-in policy does not apply to the Maryland hazardous waste program.
Under Maryland's interpretation of its regulations, although soil and other media are not solid waste or
hazardous waste in their own right, a listed hazardous waste mixed with such media must continue to be
managed as a hazardous waste unless and until it is delisted. Maryland is not authorized to implement
federal RCRA regulations establishing standards and procedures for delisting. Therefore, authority to delist
hazardous waste under RCRA subtitle C rests exclusively with EPA.

Although EPA believes that a determination by the Region that the soils treated under these alternatives no
longer contain hazardous waste under the contained-in policy is sufficient to permit these soils to be
managed thereafter as non-RCRA regulated media, EPA also has determined, in accordance with the
substantive standards of 40 C.F.R. Section 260.22, that if, after treatment, concentrations of hazardous
constituents in Site soils and sediments are below the delisting levels as set forth in Table 16, the wastes
contained in such soils and sediments are hereby delisted. In addition to making its contained-in
determination, EPA, in accordance with MDE's reguirement, is utilizing the ROD to administratively delist
those hazardous wastes which meet the substantive reguirements cited above. Soils and sediments which meet
such delisting criteria will be backfilled onsite.

During and Post-Ramediation Risk Assessment 8-nary

EPA performed a Focused Post-Remediation Risk Assessment (FRA) that evaluated the human health risks during
and post-remediation for each of the nine alternatives described above. Tables 14 and 15 summarize the
carcinogenic and non-carcinogenic risks to potential residents and workers who might be exposed to site media
(i.e., soil, ground water, air emissions).

Risks associated with the air pathway include emissions from excavation in Alternatives 3-9, emissions from
beneath the cap in Alternatives 3 and 4, and emissions from actual treatment processes in Alternatives 6-9.
Generally, risks associated with the air pathway are well within acceptable levels in all cases for both
carcinogenic and non-carcinogenic effects. The highest carcinogenic risks are associated with solid-phase
bioremediation.

Alternatives 1 and 2 would not reduce contaminant levels in soils and therefore would not reduce the current
unacceptable risks presented by the untreated soils. In Alternatives 3 and 4, soils would be capped and site
access restricted so that no exposure to contaminated soils would occur. In Alternative 5, contaminated
soils would be shipped offsite and replaced with clean fill, thus eliminating the possibility of exposure to
contaminants. Assuming that the thermal treatment alternatives 6 and 7 would
achieve the cleanup level of 0.1 ppm B(a)P eguivalence for surface soil, the associated risks to residents
and workers through direct contact exposure with contaminated soils would be very low and within acceptable
levels for both carcinogenic and non-carcinogenic effects. The predicted post-remedial soil
concentrations of contaminants for the bioremediation alternatives 8 and 9 are somewhat higher than for
Alternatives 6 and 7 and result in risks to future site residents or workers that are higher than in
Alternatives 6 and 7 but are still within the acceptable carcinogenic and non-carcinogenic risk range.

-------
In Alternatives 6-9, risks associated with ground water exposure were calculated based on the predicted
post-remedial soil concentrations of contaminants that could be achieved by each of the treatment
technologies. For Alternatives 6 and 7, the carcinogenic risk associated with a subsurface soil cleanup
level of 1 ppm B(a)P eguivalence is within the acceptable risk range. The non-carcinogenic risk is slightly
above the HI of one. These risks are actually associated with ground water contamination
that would result from untreated soil left in the ground beyond the edge of the excavation which is expected
to be a minimal volume of soil. EPA expects that the thermal treatment or thermal desorption processes which
would treat the large volume of excavated soil would reduce the non-carcinogenic contaminant concentrations
below the predicted levels because these compounds are relatively volatile and easily removed by these
technologies. The associated non-carcinogenic risk to ground water would then
be lower and below the HI of one. Additionally, institutional controls temporarily restricting the use of
ground water from the shallow aguifer would be implemented and ground water monitoring would be conducted
until EPA, in consultation with MDE, determined that MCLs or other risk-based chemical-specific ARARs
had been achieved.

Carcinogenic risks from exposure to ground water following remediation in Alternative 8 are predicted to be
just above the upper limit of the acceptable risk range for the 5 year/batch treatment time and an order of
magnitude lower for the 10 year/batch treatment time. Non-carcinogenic risks to ground
water for each of these is below the HI of one. Based on predicted soil concentrations resulting from
treatment in Alternative 9, carcinogenic risk from exposure to ground water would be above the upper limit of
the acceptable risk range and the non-carcinogenic risk would be well above the HI of one.

General Statement Regarding Ecological Resources

While all remedial measures would be designed to minimize harmful impacts to ecological values of the pond
and stream as well as the surrounding wetland and upland areas, some adverse effects would be unavoidable
during implementation of Alternatives 3 through 9. These alternatives include such disruptive activities
as dredging of the pond and tributaries, excavation of soils, cap construction, and construction of soil
treatment process units for thermal and biological treatment. During the remedial design, EPA would
determine the expected extent of the effects on ecological resources and would, in consultation with the FWS
and NOAA, evaluate the necessity for restorative and/or mitigative measures to address such effects. Those
measures would then be implemented during the Remedial Action.

9.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES

The nine remedial alternatives described above were evaluated in detail to determine which would be the most
effective in achieving the goals of CERCLA, and in particular, achieving the remedial action objectives for
the Site identified in Section 7.0, above. EPA uses the nine criteria set forth in the NCP, 40 C.F.R.
§300.430 (e) (9) (iii) to evaluate remedial alternatives. These criteria are summarized in Table 19. The
first two criteria (overall protection of human health and the environment and compliance with ARARs) are
threshold criteria. The selected remedy must meet both of these threshold criteria (except when an ARAR
waiver is invoked). The next five criteria (long-term effectiveness and permanence, reduction of toxicity,
mobility, or volume through treatment, short-term effectiveness, implementability, and cost) are the primary
balancing criteria. The remaining two criteria (state and community acceptance) are referred to as modifying
criteria and are taken into account after public comment is received on the Proposed Plan.

The following discussion summarizes the evaluation of the nine remedial alternatives developed for the SMWT
Site against the nine evaluation criteria.

9.1 Overall Protection of Human Health and the Environment

Alternatives 5, 6 and 7 satisfy this criterion by removing contaminated soils and sediments and shipping them
offsite (Alternative 5), thermally destroying contaminants onsite (Alternative 6), or thermally separating
contaminated materials from Site soil for offsite disposal (Alternative 7). NAPLs and
any grossly contaminated soils would also be removed and shipped offsite for treatment and disposal. All
three alternatives also include treatment of surface water and ground water from the dewatering process
during remediation, and monitoring and institutional controls temporarily restricting ground water use

-------
following remediation to assure protective ground water and surface water levels have been achieved. Thus,
all contaminated media would be addressed, and the Site would be protective of human health and the
environment. This would allow for unlimited future use of the property once EPA, in consultation with MDE,
had determined that ground water ARARs had been achieved. Risks to residents from air emissions during
remediation are predicted to be acceptable. Risks from direct contact with treated soil
and ingestion of ground water post-remediation are predicted to be acceptable for residents and workers.

Alternatives 8 and 9 would provide similar protection to human health and the environment provided they are
able achieve the established cleanup levels. However, it is unlikely that either solid-phase or slurry-phase
bioremediation would be able to achieve as great a reduction in contaminant concentrations as
Alternatives 6 or 7. Higher post-remedial soil concentrations would result in higher residual risk, thus
necessitating further treatment and/or more permanent land use restrictions, carcinogenic risks due to ground
water ingestion associated with the predicted soil concentrations for Alternatives 8 and 9 are
above the acceptable level of 1 x 10-4 and the non-carcinogenic risk for Alternative 9 is well above the
acceptable HI of one.

Alternatives 3 and 4 are comparatively less protective than Alternatives 5-7 because contaminated media
would remain onsite. Alternatives 3 and 4, both of which include capping of contaminated materials as an
integral part of the alternative, would, in part, rely on land use restrictions to protect human health and
the environment. Both alternatives rely upon capping to prevent or minimize future ground water
contamination or movement of existing ground water contamination by minimizing infiltration of rain water
into the soil. Both alternatives also rely on the sheet pile wall and clay layer beneath the Site to
reduce the potential for offsite migration of contaminated ground water and DNAPL. The cap would also reduce
the potential for future contact with contaminated soil as long as it remained intact.

Alternative 2 relies primarily upon institutional controls to prevent future human exposure to Site
contaminants. While the Site would be fenced, there would be no other barrier to protect humans or wildlife
from exposure to Site contaminants. Should future Site use be inconsistent with the institutional controls,
human exposure to Site contaminants could result in a cancer risk in excess of 1 x 10-4. This is the same
risk as would be expected under Alternative 1 which contains no provision for
preventing exposure to contamination and is not protective of human health and the environment. As
Alternatives 1 and 2 do not pass the threshold criterion of overall protection of human health and the
environment, neither alternative will be evaluated further in the comparative analysis.

9.2 Compliance with ARARS

The summary of the alternatives in Section 8.0, above, presented an evaluation of the ability of each of the
nine alternatives to comply with ARARs, including a review of chemical-specific, location-specific, and
action-specific ARARs. All alternatives will meet all of their respective ARARs. Table 18 includes a
complete list of ARARs pertaining to all of the alternatives.

In Alternatives 6-9, once treated site soils and sediments meet the standards for EPA's determination that
the soils and sediments no longer contain hazardous waste and the criteria for delisting set forth in Table
16, such soils would not be considered hazardous waste or solid waste and would not need to
be managed in accordance with either EPA's or Maryland's RCRA subtitle C (hazardous waste) or subtitle D
(solid waste) reguirements.

9.3 Long-Term Effectiveness and Permanence

Alternatives 5, 6 and 7 afford the highest degree of long-term effectiveness and permanence. All would
permanently reduce the levels of onsite contaminants to levels that would allow for unrestricted use of the
Site. Alternative 5 would do so by removing soil that would pose a threat through direct contact,
ingestion or inhalation, as well as soil and DNAPL that would pose a threat to ground water. This material
would be treated and disposed of offsite, and the Site would be backfilled with clean fill. Alternatives 6
and 7 would thermally treat Site soil, removing contaminants from the soil and either destroying them
(Alternative 6) or recovering them and sending them offsite for recycling or further treatment and disposal
(Alternative 7). As would alternative 5, these alternatives would remove soil that

-------
would pose a threat through direct contact, ingestion or inhalation, and soil and DNAPL that would pose a
threat to ground water sources.

Alternatives 8 and 9 would also result in a permanent reduction in levels of contaminants onsite, although it
is not expected that the extent of the reduction achieved will egual that of Alternatives 5, 6 and 7.
Alternatives 8 and 9 are more likely to result in higher post-remedial soil concentrations and more permanent
restrictions on future use of the Site.

Alternatives 3 and 4 afford a comparatively lesser degree of long-term effectiveness than Alternatives 5-7
because they leave all contaminated material onsite and rely upon capping, subsurface barriers, and
institutional controls to prevent future exposure to Site contaminants. Under both alternatives, capping
would effectively prevent contact with contaminated soil, as long as the cap remained intact. The existing
sheet pile barrier wall would prevent the offsite migration of contaminated shallow ground water; however,
the long-term performance of sheet pile walls at Superfund sites has never been tested. In addition, these
alternatives rely upon the integrity of the clay layer underlying the Site to prevent migration of
contaminated ground water and DNAPL to deeper aguifers. EPA believes that the clay
layer will serve as an effective barrier in preventing the downward migration of contaminants.

9.4 Reduction of Toxicity, Mobility or Volume through Treatment

Alternatives 5, 6, 7, 8 and 9 utilize treatment to permanently reduce the toxicity of contaminants. All of
these alternatives involve the excavation and treatment (onsite or offsite) of approximately 97,000 CY of
contaminated soil, including soil containing DNAPL. Under Alternative 5, the soil would be treated
and disposed of offsite, and clean fill placed onsite. Under Alternatives 6 and 7, soil would be thermally
treated onsite and backfilled onsite. This soil would not pose an unacceptable risk to human health or the
environment. Under Alternatives 8 and 9, the treated soil would also be placed back onsite; however, this
soil would likely contain higher residual levels of contaminants than would the thermally treated soil and
thus would be less effective in reducing toxicity. Alternatives 5, 6, 7, 8 and 9
also include the treatment of contaminated ground water recovered during the excavation process, and the
offsite treatment and disposal of DNAPL material separated from the recovered ground water. This would
provide additional reduction in toxicity and volume of contaminants onsite. Because it includes the addition
of amendments to the soil, Alternative 8 will result in an increase in the volume of treated soil.

Alternatives 3 and 4 include a provision for the possible collection of DNAPL from the containment area via
the existing trench or some other extraction system. Any DNAPL recovered would be transported offsite for
treatment and disposal. This would reduce the toxicity and volume of contamination at the Site
to a small degree, but the large volume of contaminated soil and sediment would remain untreated.

9.5 Short-Term Effectiveness

The risk posed by excavation activities during the course of each alternative was evaluated in the Focused
Risk Assessment. None of the alternatives under consideration are expected to pose an unacceptable risk to
nearby residents during remediation. Risks due to the emissions from the treatment processes themselves were
calculated for Alternatives 6 through 9. All were found to be acceptable.

For Alternatives 5-9, all of which include substantial excavation of contaminated soil, dust and
sedimentation control measures would be reguired during the handling of contaminated material. Alternatives
3 and 4 would reguire these measures as well, although to a lesser degree as excavation would be less
extensive.

The ecological system in the east and west tributaries and the pond would be impacted by dredging of
sediments in Alternatives 3 through 9. Alternatives 3 and 4 would also affect terrestrial habitats during
excavation although to a lesser extent than in Alternatives 5 through 9 which reguire extensive excavation.

Short-term effects during the remediation would be ongoing for less than 5 years for alternatives 3 through
7. The short-term effects associated with Alternative 8 may extend over several decades and those associated
with Alternative 9 are estimated to occur over a 15 year period.

-------
9.6 Implementability

Of the two capping/containment options, Alternative 4 (Partial
Site Cap) would be easier to implement. This alternative involves the capping of a considerably smaller area
of the Site than Alternative 3 (approximately 4 acres, as compared to 23 acres). While it reguires some
excavation, the soil to be excavated is generally shallow and would reguire no special excavation technigues.
Alternative 3 would reguire the clearing, grading and capping of the entire Site. The eguipment and
materials reguired for both alternatives are readily available. Periodic maintenance of both the cap and the
ground water treatment system would be reguired to ensure the continued performance of the remedial action.

Alternatives 5, 6, 7, 8 and 9 all involve the excavation of 97,000 CY of contaminated soil, some of which
will be contaminated with NAPL. Excavation to depths of up to 40 feet will be reguired. Within the
containment area, an engineered tie back system will be installed to provide stability during excavation.
Because soil will be excavated from below the existing water table, it will be necessary to dewater the soil
to the extent possible prior to excavation.

Alternative 5 would reguire the least amount of additional handling of the contaminated soil. Soil would be
recontainerized and shipped offsite for treatment and disposal. This is a standard operation that should be
simple to implement. The successful implementation of this alternative would, of course,
be contingent upon the availability of permitted offsite treatment and disposal facilities which could handle
this volume and type of waste.

Alternatives 6 and 7 include the construction and operation of transportable thermal treatment systems at the
Site. These systems are existing units which are moved from site to site on a series of trucks, and then
assembled. There are a significant number of vendors who have experience in operating a variety of
different units that could be used at this Site. The handling of the material produced by the treatment
process may vary, depending on exactly which unit is used. Generally, incinerators will produce ash that
must be rehydrated prior to being backfilled. Based on treatability studies conducted using Site
soil, the ash is not expected to exhibit a hazardous waste characteristic. Furthermore, it is expected that
the listed hazardous constituents in the soil will be treated such that they no longer present a threat to
human health and the environment and can therefore be delisted. It may be necessary to mix clean fill into
the ash to lend the material structural stability and to promote vegetative growth. Thermal desorption units
may produce a soil-like treatment product that can be handled as would the incinerator ash.

Alternative 8 involves a labor-intensive operation and would reguire a long time to implement. Due to
limitations in available space, soil would have to be excavated in several lifts and treated in batches.
This would reguire numerous mobilizations/demobilizations of excavation and hauling eguipment, continuous
treatment of ground water in the excavation area, and security control around the excavation and stockpiling
areas for several decades. The biological treatment units would reguire continuous maintenance, including
regular turning or tilling, irrigation, nutrient addition, and monitoring.

Alternative 9 would involve the greatest amount of material handling as it involves two separate treatment
processes, soil washing followed by slurry-phase bioremediation. Available land space would determine
whether soil washing and biological processes could be implemented simultaneously, and would determine the
size of the reactors that could be used, thus determining the duration of treatment. A pilot scale
treatability study would be reguired to determine the optimal retention time of the slurry in the reactor.

9.7 Cost

Capital costs for the capping alternatives (Alternatives 3 and 4) are relatively low but these alternatives
would be less protective than the treatment alternatives (Alternatives 6 and 7). The costs for the offsite
disposal alternative (Alternative 5) are very high but provide approximately the same
protectiveness as Alternatives 6 and 7 which are considerably less expensive. For the two thermal treatment
alternatives, capital costs for Alternative 6 are twice those of Alternative 7 but would result in
approximately the same reduction in contaminant concentrations and risk. Capital costs for Alternatives 8
and 9 are similar to Alternative 7 but these alternatives are less certain to achieve a similar reduction in
contaminant concentrations and risk. Annual operation and maintenance costs are similar for Alternatives

-------
3-9. For Alternatives 3 and 4, it was assumed that O&M would continue for 30 years. For purposes of cost
estimation for Alternatives 5 through 9, O&M is anticipated to occur for 5 years.

9.8 State Acceptance

MDE supports EPA's selection of Alternative 7 Thermal Desorption as the remedy for the Site. However,
because MDE believes that EPA has selected a remedy which effectively eliminates the Site contamination
through treatment and offsite disposal, MDE does not believe extended or indefinite ground water monitoring
beyond 5 years is warranted.

9.9 Community Acceptance

Generally, the local community has expressed no opposition to the selected remedy. In written correspondence
submitted to EPA, the St. Mary's County Commissioners have recommended that EPA select
Alternative 7, Thermal Desorption, as the remedy for this Site. They have noted, however, that they do not
believe that EPA evaluated the bioremediation alternatives adeguately and that bioremediation may have been
able to clean up the Site "in a more benign, less costly manner." The Commissioners have also stated
that the thermal desorption system must be designed to recycle inert gases, must be heated externally, and
must have proper emissions controls. Finally, the Commissioners want the site cleaned up to a level which
will allow it to be used productively following remediation. The Commissioners are opposed to the
capping alternatives. The Southern Maryland Environmental Awareness Coalition (EAC), a local citizens group,
has expressed a position similar to that of the Commissioners. The EAC is endorsing thermal desorption but
has health and safety concerns associated with the technology.

10.0 SELECTED REMEDY: DESCRIPTION AND PERFORMANCE STANDARDS

Following review and consideration of the information in the Administrative Record file, the reguirements of
CERCLA and the NCP, and public comment, EPA has selected Alternative 7 (Excavation and Thermal Desorption) as
the remedy for the SMWT Site. Alternative 7 meets the threshold criteria of overall
protection of human health and the environment and compliance with ARARs, and provides the best balance of
long-term effectiveness and permanence, reduction of toxicity, mobility or volume through treatment,
shore-term effectiveness, implementability and cost.

The selected remedy consists of the following components:

! Dewatering of the containment area in preparation for
the excavation of subsurface soil and DNAPLs below the
water table followed by onsite treatment of water
generated in the dewatering process and discharge of
treated water to the west tributary;

! Excavation of approximately 97,000 CY of soil from within
and outside of the sheet pile wall and dredging of sediments
from the onsite pond and segments of the east and west
tributaries that contain contaminants in excess of the
established cleanup levels set forth in Section 7.0;

! Dewatering of saturated soils/sediments onsite in
preparation for treatment by thermal desorption, followed by
onsite treatment of water generated in the dewatering
process and discharge of treated water to the west tributary;

-------
water treatment residues, recondensed contaminants from the
thermal desorption treatment process, and any grossly
contaminated soil/sediment that is not amenable to treatment
by thermal desorption prior to offsite shipment for
treatment and disposal;

! Onsite treatment of excavated soils and sediments by a
thermal desorption process;

! Sampling of treated soils and sediments to ensure delisting
levels have been achieved;

! Backfilling with clean fill below the water table in the
containment area and with treated soil/sediments above the
water table in the containment area and in all other
excavated areas;

! Pumping and treating of surface water from the onsite pond
until the sources of contamination to the surface water
(i.e., soil, sediment, ground water) are remediated.
Treatment of surface water in onsite water treatment system
followed by discharge to the west tributary;

! Ground water, stream and wetlands monitoring;

! Implementation of institutional controls temporarily
restricting ground water use in the shallow aguifer;

! Building demolition and cutting off of the sheet pile wall
following remediation, as determined necessary. Offsite
disposal of building rubble and sheet piling; and

! Maintenance of perimeter fencing until access restrictions
are no longer necessary.

The remedy and mandatory performance standards are described in detail below.

10.1 Excavation of Soils, Dredging of Sediments, and DNAPL Removal

Based on the cleanup levels set forth in Section 7.0, above, an estimated 97,000 CY of soils and sediments
shall be excavated and/or dredged from the Site. This includes surface and subsurface soils from areas both
within and outside of the sheet pile wall and sediments in the onsite pond and segments of the
east and west tributaries. Within the sheet pile wall excavation must go as deep as the clay layer that
underlies the Site in order to be able to reach and remove the DNAPL that is present in the subsurface.
Because this will entail excavation below the current water table, the containment area must be dewatered
prior to excavation. DNAPL collected during excavation and dewatering shall be staged onsite prior to
transport offsite for treatment and disposal. Ground water generated from dewatering of the containment area
shall be treated onsite in the existing water treatment system. Treated water shall be discharged to the
west tributary.

-------
Outside of the sheet pile wall, excavation is expected to extend only to an approximate depth of two feet,
except in the land treatment area where it is expected to extend to an approximate depth of five to seven
feet.
Soil and sediment samples shall be collected throughout the Site. Soil shall be analyzed for the PAH
compounds and sediments for PAH compounds and PCP. The results shall be compared to the cleanup levels to
determine the exact area and volume of soils/sediments requiring excavation. The number and location of
samples and the analytical methods to be used shall be determined during the remedial design.

Performance Standards for the Excavation of Soils and Dredging of Sediments and DNAPL Removal:

1. The containment area shall be dewatered as necessary to
allow excavation of contaminated soil and DNAPL that
currently exists in the saturated zone below the top of the
shallow water table.

2. All surface soils containing greater than 0.1 ppm B(a)P
equivalents shall be excavated from all areas of the Site.
Surface soils are defined as the upper two feet of soil in
any given area. All subsurface soils containing greater
than 1.0 ppm B(a)P equivalents shall be excavated from the
land treatment area, the containment area and, if necessary,
any other areas of the Site as determined by sampling during excavation.

3. All sediments in the onsite pond and the east and west
tributaries containing greater than 3.2 ppm low molecular
weight PAHs, 9.6 ppm high molecular weight PAHs, or 0.4 ppm
PCP shall be dredged from these areas. Low molecular weight
PAHs include, but are not limited to, acenaphthene,
acenaphthylene, anthracene, fluorene, 2-methyl naphthalene,
naphthalene, and phenanthrene. High molecular weight PARs
include, but are not limited to, benz(a)anthracene,
benzo(a)pyrene, chrysene, dibenzo(a,h)anthracene,
fluoranthene, and pyrene.

4. Excavation activities shall be conducted in compliance with
the substantive requirements of Maryland regulations for the
control of noise pollution (COMAR 26.02.03.02 A(2) and B(2)
and COMAR 26.02.03.03 A), storm water management (COMAR
26.09.02), and erosion and sediment control (COMAR
26.09.01.11). In preparation for treatment and following
treatment in preparation for backfilling, excavated soils
and sediments shall be staged and managed onsite in
accordance with standards applicable to generators of
hazardous waste (COMAR 26.13 . 03.02-.05) and standards
applicable to treatment, storage, and disposal facilities
(COMAR 26.13.05.09-.12)

5. Ground water generated from the dewatering process shall be
treated onsite in the existing water treatment system to
meet the substantive requirements of the NPDES program and
Maryland Discharge limitations (COMAR 26.08.01.02, COMAR
26.08.02.03, COMAR 26.08.03.01 and .07, and 33 U.S.C. §1342,
40 CFR Part 125, Subpart K, and 40 CFR Part 136) before
being discharged to the west tributary. The water treatment
system shall be operated in accordance with Maryland water
quality certification regulations (COMAR 26.08.02.10).

-------
6. NAPL collected during excavation and dewatering, any grossly
contaminated soil and sediment not amenable to treatment by
thermal desorption, and any water treatment residuals
determined to be hazardous wastes, either listed or
characteristic (COMAR 26.13.02.01-.14, and .16-.19, 40 CFR
§261.24 (toxicity characteristic) and 40 CFR §261.31 (F
Wastes)), shall be disposed of offsite at a RCRA hazardous
waste facility and shall be staged and managed onsite and
prepared for offsite disposal in compliance with standards
applicable to generators of hazardous waste (COMAR
26.13.03.02, .03, .04 and .05) and standards applicable to
treatment, storage, and disposal facilities (COMAR
26.13 . 05.09-.12) and land disposal restrictions for waste
analysis, treatment standards, and storage, respectively (40
C.F.R. 268.7, 268.9, and 268.50).

7. All excavation/dredging activities that will affect
wetlands, floodplains, or waters of the United States shall
be conducted in accordance with the substantive reguirements
of Maryland Wetlands Regulations (COMAR 08.05.04), the
Procedures for Implementing the Reguirements of the Council
on Environmental Quality on the National Environmental
Policy Act (40 CFR part 6, Appendix A), and Clean Water Act
Dredge and Fill Reguirements (33 USC Section 1344, 40 CFR
Part 230) and Army Corps regulations (33 CFR Parts 320-330).

10.2 Onsite Thermal Desorption of Excavated Boils and Dredged Sediments

All excavated soils and sediments containing concentrations of contaminants above the cleanup levels shall be
treated onsite using a mobile thermal desorption system. A mobile thermal desorption unit shall be
transported to and constructed onsite, then dismantled and removed from the Site following remediation.
Contaminants in soils and sediments shall be desorbed (i.e., contaminants separated from the soil and
sediments) by heating to the appropriate temperature to volatilize the organic contaminants. The appropriate
temperature shall be determined during the remedial design. Desorbed contaminants shall then be recondensed,
or collected by some other means, and disposed of offsite in a RCRA hazardous waste disposal facility. The
actual type of desorber and the components of the system to collect treatment residuals shall be determined
during the remedial design.

Performance Standards for Onsite Thermal Desorption of Excavated Soils and Sediments:

1. Excavated soils and sediments shall be treated by thermal
desorption to achieve the following cleanup levels:
soils/sediments to be backfilled as surface soils shall be
treated to 0.1 ppm B(a)P eguivalents; soils/sediments to be
backfilled as subsurface soils shall be treated to 1.0 ppm
B(a)P eguivalents. Treated sediments shall not be placed
back in the tributaries, but shall be backfilled in the
containment area. For delisting purposes, all soils and
sediments shall also be treated to the health-based
delisting levels specified in Table 16.

2. The thermal desorber shall be operated in accordance with
the substantive reguirements of RCRA regulations for owners
and operators of hazardous waste treatment, storage and
disposal facilities, that treat hazardous waste in
miscellaneous units (COMAR 26.13.05.16-1 and 40 CFR Subpart
X, Part 264.600 - 264.603). If necessary, ground water

-------
appropriation for use in the treatment process shall be
approved in accordance with COMAR 08.05.02.

3 Air emissions from the thermal desorber shall be in
compliance with substantive requirements of Maryland
regulations governing air pollutants and air quality for
VOCs (COMAR 26.11.06.06), visible emissions, particulates,
and nuisances (COMAR 26.11.06.02, .03, .08) and with federal
air emissions standards for process vents (40 CFR Part 264,
Subpart AA) and equipment leaks (40 C.F.R. Part 264, Subpart BB).

4. Water generated in the treatment process that is not
recycled in the process shall be treated in the onsite water
treatment system prior to discharge to the west tributary.
See Section 10.1, paragraph 5. for performance standards for
the water treatment system.

5. Any other treatment residuals generated in the thermal
desorption treatment process (e.g., recondensed organic
contaminants) determined to be hazardous wastes either
listed or characteristic (COMAR 26.13.02.01- .14, and .16-
.19, 40 CFR §261.24 (toxicity characteristic), and 40 CFR
§261.31 (F wastes)) shall be treated and/or disposed at a
RCRA hazardous waste offsite facility and shall be managed
onsite and prepared for disposal in compliance with
standards applicable to generators of hazardous waste (COMAR
26.13.03.02, .03, .04, .05), standards applicable to
treatment, storage, and disposal facilities (COMAR
26.13.05.09-.12) and land disposal restrictions for waste
analysis, treatment standards, and storage, respectively (40
C.F.R. 268.7, 268.9, and 268.50).

10.3 Backfilling of Clean Fill and Treated Soils and Sediments

Following excavation in the containment area, clean fill shall be backfilled below the water table. Treated
soil and sediment that has met the cleanup levels and delisting levels set forth in Section 10.2, above,
shall be backfilled onsite. The Site shall then be graded and revegetated.

A statistical analysis of the treated soils and sediments shall be conducted before backfilling to ensure
that the cleanup levels and delisting levels have been achieved. The frequency of sampling and the
analytical methods to be employed shall be determined during the remedial design.

Performance Standards for Backfilling of Clean Fill and Treated Soils and Sediments:

1. Clean fill shall be backfilled below the water table in
the containment area. Soil and sediment treated by
thermal desorption that has achieved the subsurface
soil cleanup level of 1 ppm B(a)P equivalents shall be
backfilled in the subsurface above the clean fill and
in other subsurface areas of the Site that have been
excavated. Treated soil and sediment that has achieved
the surface soil cleanup level of 0.1 ppm B(a)P
equivalents shall be backfilled above the subsurface
soil. Treated sediments shall not be placed back in the
tributaries, but shall be backfilled in the containment
area. Prior to backfilling, treated soils/sediments
shall be sampled and analyzed to verify that cleanup

-------
and delisting levels have been achieved.

2. For delisting purposes, no soils and sediments backfilled
onsite shall contain contaminants above the delisting levels
specified in Table 16. Additionally, the material to be
backfilled must not exhibit any of the hazardous waste
characteristics described in COMAR 26.13.02.11-.14 (i.e.,
ignitability, corrosivity, reactivity, or toxicity). To
determine that the delisting levels have been met, the
Toxicity Characteristic Leaching Procedure (TCLP), EPA
Method 1311, shall be used.

3. The Site shall be graded appropriately to prevent
subsidence and erosion. A vegetative cover shall be
established to prevent soil erosion.

4. Backfilling activities shall be conducted in compliance
with the substantive reguirements of Maryland
regulations for the control of noise pollution (COMAR
26.02.03.02 A(2) and B(2) and COMAR 26.02.03.03 A),
storm water management (COMAR 26.09.02), and erosion and
sediment control (COMAR 26.09.01.11).

5. All backfilling activities that will affect wetlands,
floodplains, or waters of the United States shall be
conducted in accordance with Maryland Wetlands Regulations
(COMAR 08.05.04), the Procedures for Implementing the
Reguirements of the Council on Environmental Quality on the
National Environmental Policy Act (40 CFR part 6, Appendix
A), and Clean Water Act Dredge and Fill Reguirements (33 USC
Section 1344, 40 CFR Part 230) and Army Corps regulations
(33 CFR Parts 320-330) .

10.4 Surface Water Pumping and Treating

Pursuant to the most recent removal action at the Site, surface water is currently pumped from the onsite
pond, treated in the recently constructed onsite water treatment system, and discharged to the west
tributary. This activity shall be continued pursuant to this ROD.

Performance Standard for Surface Water Pumping and Treating:

1. Surface water shall be pumped from the onsite pond in
sufficient guantity to prevent untreated surface water from
flowing to the west tributary. Pumping and treating shall
continue until the sources of contamination to the surface
water (i.e., soil, sediment, ground water) have been remediated.

2. See section 10.1, Performance Standards 5 and 6 for
standards pertaining to operation of the water treatment
system, discharge reguirements, and treatment residue disposal.

10.5 Ground Water Monitoring

A ground water monitoring program shall be implemented during and after remediation to evaluate the
effectiveness of the soil remediation. Ground water in the shallow aguifer shall be sampled before the start
of remediation to establish a baseline of contaminant concentrations. Following remediation, ground
water in the shallow aguifer shall be monitored to assure that the soil remediation sufficiently reduced

-------
contaminants in the ground water to ensure protection of human health and the environment and to verify that
clean closure requirements have been met.

Beginning in 1994, four wells screened in the deeper sand unit just below the blue clay layer beneath the
site, have been sampled periodically to ensure that contaminants are not migrating through the clay.
Monitoring of this sand unit shall continue throughout the design and implementation of the remedy
and following remediation as a part of the Site monitoring program.

Performance Standards For Ground Water Monitoring:

1. New monitoring wells shall be installed in accordance
with State requirements for well construction (COMAR
26.04.04). Wells shall be installed by persons
certified by the Board of Well Drillers pursuant to
COMAR 26.05.01.

2. Monitoring wells shall be located in the shallow
aquifer in sufficient nnmher and location to determine
the effectiveness of the soil remediation at the Site.
Monitoring wells shall be located in the deep aquifer
in sufficient number and location to verify that
contamination is not migrating through the clay layer.
The number and location of wells, existing or newly
installed, to be included in the ground water
monitoring network shall be determined during the
remedial design. The frequency and duration of sampling
and analytical parameters and methods to be used shall
also be determined during the remedial design.

3. Post-remediation ground water results shall be
evaluated to determine if RCRA clean closure
requirements have been achieved and to ensure that
contaminant concentrations do not exceed Safe Drinking
Water Act Maximum Contaminant levels (40 CFR Sections
141.11 - .12, and 141.61 - .62), non-zero MCL Goals (40
CFR Section 141.5 -.51), or if no MCLs or MCLGs are
available, other appropriate risk-based chemical-
specific guidelines that are available at that time
(e.g., information found in the Integrated Risk
Information System (IRIS) developed by the EPA Office
of Research and Development, EPA Health Advisories on
Drinking Water developed by the EPA Office of Drinking
Water, and Health Effects Assessments developed by the
EPA Environmental Criteria and Assessment Office).

4. A statistical analysis of the ground water data shall be
performed to determine that contaminant concentrations have
stabilized at or below the MCLs or other chemical-specific
ARARs. Such determination shall be made in consultation
with MDE and shall be based on the policy reviews of the
remedial action. The policy reviews shall be conducted no
less often than every five years from completion of the
construction of the remedial action in accordance with EPA
guidance set forth in Structure and Components of Five-Year
Reviews, May 23, 1991, OSWER Directive 9355.7-02 and
Supplemental Five-Year Review Guidance, OSWER Directive
9355.7-02A. Policy reviews shall be conducted as long as

-------
hazardous substances remain onsite and prevent unlimited use
of and unrestricted exposure to the Site.

10.6 Stream and Wetland Monitoring

A fresh water pond is located onsite from which flows the west tributary (Old Tom's Run). The east tributary
emanates from the eastern part of the Site and eventually converges with the west tributary. Approximately
two to three acres of wetlands are located in these areas (Figure 10). While all remedial measures shall be
designed to minimize harmful impacts to ecological values of the pond and stream, as well as the surrounding
wetland and upland areas, some adverse effects will be unavoidable during
implementation of the remedy. During the remedial design, EPA shall determine the expected extent of the
effects on ecological resources and shall, in consultation with the FWS and NOAA, evaluate the necessity for
restorative and/or mitigative measures to address such effects. Those measures shall then be
implemented during the remedial action.

A stream and wetland monitoring program shall be implemented to evaluate Site impacts on these areas, to
identify any changes in conditions in the stream or wetlands due to implementation of the selected remedy,
and to assess the need for additional stream and wetland studies or additional remedial action.

During the remedial design phase, EPA shall determine the number and location of sampling points in the
streams and wetlands and the analytical parameters and methods to be employed sufficient to perform the
ecological evaluation for the Site and make the assessments described above.

Performance Standard for Stream and Wetland Monitoring:

1. The stream and wetland monitoring program shall be
implemented to evaluate the tributaries and wetlands
impacted by the Site, to identify any changes in
conditions in the tributaries or wetlands due to
implementation of the selected remedy, and to assess
the need for additional stream and wetland studies or
additional remedial action.

2. Ecological monitoring shall be conducted annually with
the first round conducted prior to the start of the
remedial action to establish baseline conditions. The
study conducted by the U.S. FWS in 1990, as discussed
in Section 6.3, documented the impacts of the Site on
aguatic biota and delineated wetlands in the area of
the Site. This document shall serve as a reference for
the ecological evaluation of baseline conditions. The
baseline study of the tributaries shall be performed in
accordance with the modified Rapid Bioassessment
Protocols for Use in Streams and Rivers, Benthic
Macroinvertebrates and Fish, EPA/444/4-89-001, May
1989. Wetlands delineation shall be performed in
accordance with COMAR 08.05.04 and 33 U.S.C. 1344, 40
CFR Part 230.

3. Monitoring shall continue for such time as EPA, in
consultation with MDE, determines is necessary to
assure protection of human health and the environment.
This determination shall be based on the statutory
reviews of the remedial action which shall be conducted
no less often than every five years from completion of
the construction of the remedial action in accordance
with EPA guidance set forth in Structure and Components

-------
      of Five-Year Reviews, May 23, 1991, OSWER Directive
      9355.7-02 and Supplemental Five-Year Review Guidance,
      OSWER Directive 9355.7-02A.  Policy reviews shall be
      conducted as long as hazardous substances remain onsite
      and prevent unlimited use of and unrestricted exposure
      to the Site.

10.7    Institutional Controls

As soon as practicable, EPA shall ensure that institutional controls are in place to prevent installation of
drinking water wells on the property in the shallow aguifer.  Such institutional controls shall remain in
effect until EPA determines that they are no longer reguired to protect human health and the environment.

Performance Standard for Institutional Controls:

The objective of the institutional controls is to limit the potential for exposure to contaminated ground
water in the shallow aguifer and to minimize the extent to which the contaminant plume could be extended as a
result of breaching of the clay layer beneath the Site.  The institutional controls shall be maintained until
EPA, in consultation with MDE, determines that MCLs or other risk-based chemical-specific ARARs have been
achieved as specified in the performance standards for ground water monitoring in Section 10.5, above.

10.8    Building Demolition

Any buildings that are not necessary for remedial action or operation and maintenance activities and that are
contaminated with hazardous substances shall either be decontaminated or demolished and the rubble and any
decontamination wastes shipped offsite for treatment and disposal.

Performance Standards for Building Demolition:

All buildings that are not necessary for the remedial action or operation and maintenance activities shall be
sampled to determine if they are contaminated with hazardous substances.  If so, the building(s) shall either
be decontaminated or demolished. The rubble and any decontamination wastes shall be handled onsite
and prepared for shipment offsite in accordance with RCRA regulations for generators of hazardous wastes
(COMAR 26.13.03.02-.05) .

10.9    Sheet Pile Wall

Once EPA determines that the sheet pile wall, in its role as a containment structure, is no longer necessary
to protect human health and the environment, the above-ground portion of the sheet
piling shall be tested to determine if it is contaminated with hazardous substances.  If it is found to be
contaminated with hazardous substances, the sheet piling shall be handled in one of the following manners:
(1) decontaminated in place;  (2) cut off below the ground surface and prepared for offsite shipment to
a hazardous waste disposal facility in accordance with RCRA regulations for generators of hazardous wastes
(COMAR 26.13.03.02-.05);  or,  (3) cut off below the ground surface, decontaminated, and shipped offsite for
recycling or disposal in a solid waste disposal facility.

10.10   Perimeter Fencing

The chain-link fence with locking gates that currently surrounds the Site shall be maintained in a manner
sufficient to prevent unauthorized access to the Site until such time as EPA determines that all soil cleanup
levels have been achieved and that exposure to Site media will not result in an unacceptable risk to human
health or the environment.

10.11   Miscellaneous Performance Standards

All remedial activities shall be implemented in a manner that will not adversely impact any identified
endangered species pursuant to the Endangered Species Act of 1978 (16 U.S.C. §1531 et seg.,  50 C.F.R. Part

-------
402) or historic resources pursuant to the Archaeological and Historical Preservation Action of 1974 (16
U.S.C. §469) and the National Historic Preservation Act of 1966, as amended (16 U.S.C. §470 et seq., 36
C.F.R. Part 800).

This remedial action shall comply with applicable statutory and regulatory requirements under RCRA Subtitle C
relating to Corrective Action of solid waste management units, including 40 C.F.R. Part 264, Subparts F and
S.

The remedial action shall meet the RCRA clean closure requirements for the former landfill areas (i.e., the
land treatment area and the containment area) (COMAR 26.13.05.07 and 26.13.05.14).

11.0 GROUND WATER CONTINGENCY

Based on the ground water concentrations that were predicted to occur in the modeling performed during the
FFS, ground water in the shallow aquifer should be restored to drinking water conditions following
remediation of the soils and sediments to the established cleanup levels. It may become apparent during
implementation of the post-remediation ground water monitoring program that ground water concentrations are
remaining at levels above what is considered to be protective of human health and the environment. In such
case, EPA may require that any of the following measures be taken for an indefinite period of time:

1. cleanup levels may be modified and chemical-specific ARARs
may be waived in accordance with CERCLA and the NCP;

2. institutional controls may be modified or extended in
duration to restrict access to those portions of the aquifer
where contamination is above safe levels; and

3. remedial technologies for further ground water restoration
may be evaluated and implemented in accordance with CERCLA
and the NCP.

The decision to invoke any or all of these measures may be made by EPA, in consultation with MDE, during
reviews of the remedial action. Such policy reviews will be conducted at least every five years from
completion of the construction of the remedial action in accordance with EPA guidance set forth in Structure
and Components of Five-Year Reviews, May 23, 1991, OSWER Directive 9355.7-02 and Supplemental Five-Year
Review Guidance, OSWER Directive 9355.7-02A. Policy reviews shall be conducted as long
as hazardous substances remain onsite and prevent unlimited use of and unrestricted exposure to the Site. If
necessary, EPA will issue an Explanation of Significant Differences, a ROD amendment, or a new ROD in
accordance with CERCLA and the NCP to address the required change to the remedy.

12 . 0 STATUTORY DETERMINATIONS

EPA's primary responsibility at Superfund sites is to undertake remedial actions that are protective of human
health and the environment. In addition, Section 121 of CERCLA, 42 U.S.C. Section 9621, establishes several
other statutory requirements and preferences. These requirements specify that when complete,
the selected remedial action for each site must comply with applicable or relevant and appropriate
environmental standards established under federal and state environmental laws unless a statutory waiver is
invoked. The selected remedy also must be cost effective and utilize treatment technologies or resource
recovery technologies to the maximum extent practicable. Finally, the statute includes a preference for
remedies that permanently and significantly reduce the volume, toxicity or mobility of hazardous substances.
The following sections discuss how the selected remedy for this Site meets these statutory requirements.

12.1 Protection of Human Health and the Environment

The selected remedy protects human health and the environment by reducing contaminant concentrations in all
Site media, by controlling exposure to contaminated soil, sediment, ground water and surface water and by
reducing contaminant loading to ground water, surface water, and sediments.

-------
Excavation and treatment of soils and sediments will reduce contaminant concentrations to a level where they
will no longer present an unacceptable risk to human health and the environment through direct contact.
Excavation and treatment of contaminated soils and sediments and removal of DNAPLs in the subsurface will
also prevent further migration of contamination from the Site and effectively reduce contaminant levels in
the ground water in the shallow aguifer and in the local surface water and sediments. Conseguently, these
measures will reduce the potential for exposure via direct contact or ingestion.  Once the cleanup levels
have been achieved, the carcinogenic risk associated with
exposure to soils and ground water is expected to be within EPA's target risk range of 1 x 10-6 to 1 x 10-4
and it is expected that there will be no significant potential for adverse noncarcinogenic health effects as
a result of exposure to Site media.

Ground water monitoring will provide data for evaluating the effectiveness of the remedial action and will
ensure that any unacceptable levels of contaminants in the ground water are addressed.  Ground water use
restrictions in the shallow aguifer will prevent future exposure to any remaining contaminated ground
water by limiting the future installation of wells until EPA determines that ground water ARARs have been
achieved to ensure protection of human health and the environment.

Dredging of the sediments in the pond and tributaries may impact ecological resources.  Stream and wetland
monitoring will provide a basis for additional remedial action, if it is determined to be necessary by EPA,
in order to mitigate Site impacts on the stream or wetlands.

In the short-term, air emissions from the thermal desorption process will be reduced to acceptable regulatory
levels by the installation of emission controls.  Treated ground water and surface water which is discharged
to the west tributary will meet all appropriate water guality standards and NPDES limitations in order to
prevent any adverse environmental effects.  Excavation activities will be conducted in accordance with
regulations for noise pollution and sediment and erosion control.

Through treatment, institutional controls and monitoring, this remedy will be protective of human health and
the environment during and upon completion of the remedial action.

12.2    Compliance with Applicable or Relevant and Appropriate Reguirements

The selected remedy shall attain all action-, location-, and chemical-specific applicable or relevant and
appropriate reguirements for the Site which are included in Section 10.

12.3    Cost-Effectiveness

The selected remedy, excavation and thermal desorption, is cost-effective in that it mitigates the risks
posed by the contaminants associated with the Site, meets all reguirements of CERCLA, and affords overall
effectiveness proportionate to the cost.  The estimated present worth cost for the selected remedy
is $32,300,000.  The costs associated with the capping alternatives, Alternatives 3 and 4, are comparatively
lower  ($17,000,000 and $9,000,000, respectively) but do not satisfy the statutory preference for treatment.
Alternative 6, incineration, includes treatment and would provide effectiveness similar to the selected
remedy but at almost twice the cost ($58,300,000). Alternative 5, offsite disposal is cost prohibitive with
capital costs estimated at $179,300,000.  The bioremediaton alternatives, Alternatives 8 and 9, have
estimated capital costs in the same range as the selected remedy  ($32,300,000 - $45,300,000 and $27,300,000 -
34,300,000, respectively) but are not likely to be as effective in achieving the cleanup levels established
for this Site.

12.4    Utilization of Permanent Solutions And Alternative Treatment Technologies to the Maximum Extent
        Practicable

The selected remedy for the Site utilizes permanent solutions and treatment technologies to the maximum
extent practicable via the use of the thermal desorption technology.  Of those alternatives that are
protective of human health and the environment and that comply with ARARs, EPA has determined that the
selected remedy provides the best balance of tradeoffs in terms of long-term effectiveness and permanence,
reduction in toxicity, mobility, or volume through treatment, short-term effectiveness, implementability, and

-------
cost while also considering the statutory preference for treatment as a principal element and State and
community acceptance. See Section 9.0 Summary of Comparative Analysis of Alternatives.

12.5 Preference for Treatment as a Principal Element

In keeping with the statutory preference for treatment as a principal element of the remedy, the selected
remedy provides for the treatment of contaminated soils and sediments which constitute one of the principal
threats known to exist at the Site. DNAPLs in the containment area, also a principal threat,
will be excavated and disposed of offsite as the thermal desorption process would not be amenable to treating
these wastes.

13.0 DOCUMENTATION OF SIGNIFICANT CHANGES

Section 117(b) of CERCLA, 42 U.S.C. §9717 (b), reguires an explanation of any significant changes in a ROD
from the preferred alternative originally presented in the Proposed Plan. The selected remedy described in
this ROD contains one significant change from EPA's preferred alternative in the Proposed Plan. The change
described below was made in response to comments on the Proposed Plan.

A sediment cleanup level for PCP of 0.4 ppm (dry weight basis) has been added to the cleanup levels for the
Site. This addition was necessary because the detection limits for PCP in sediment samples collected to date
have been above 0.4 ppm; therefore, it is not currently known how extensive PCP contamination may be above
this level. During the dredging operations, sediment samples shall be collected and analyzed using methods
with appropriate detection limits to detect areas where this cleanup level has been exceeded and therefore
reguires excavation.

-------
                                 TABLE 1
                      Summary of Drilling Log for
                  On-Site Production Well (Abandoned)

                  Southern Maryland Woodtreating Site
                             Hollywood,  MD
                             January, 1994
          Description

 Yellow sand and clay
Depth in
  Feet

  0-30
     Interpreted
    Geologic Unit

Pleistocene
sediments
 Blue clay                           30-50
 Yellow sand                         50-60
 Blue clay                           60-90
 Green sand, shell,  and rock         90-135
 Green clay                         135-228
 Green sand, shell and clay         228-245
 Green clay                         245-285

 Green sand, shell,  and rock        285-325
 Black sandy clay                   325-350
 Brown sand                         350-370
 Black sand and clay                370-485

 White clay                         485-493
 Pink clay                          493-495

 Green sand                         495-600
             Chesapeake Group
             Piney Point and
             Nanjemoy Formations
             Marlboro Clay
             Aguia Formation
Source:   State of Maryland Waste Management Administration records.

-------
                       TABLE  2

         CHEMICALS DETECTED  IN ALL MEDIA
          AT THE SOUTHERN  MARYLAND SITE
2,4-DIMETHYLPHENOL
2-CHLOROPHENOL
2-METHYLNAPHTHALENE
2-METHYLPHENOL
3,3-DICHLOROBENZIDINE
4-CHLOROANILINE
4-METHYLPHENOL
ACENAPHTHENE
ACENAPHTHYLENE
ACETONE
ANTHRACENE
BENZENE
BENZOIC ACID
BENZO(A)ANTHRACENE
BENZO(A)PYRENE
BENZO(B)FLUORANTHENE
BENZO(G,H,I)PERYLENE
BENZO(K)FLUORANTHENE
BIS(2-ETHYLHEXYL)PHTHALATE
BUTYLBENZYLPNTHALATE
CARBON DISULFIDE
CHRYSENE
DIBENZOFURAN
DIBENZO(A,H)ANTHRACENE
DIETHYLPHTHALATE
DI-N-BUTYLPHTHALATE
DI-N-OCTYL PHTHALATE
ETHYLBENZENE
FLOURENE
FLUORANTHENE
INDENO(1,2,3-CD)PYRENE
METHYLENE CHLORIDE
NAPHTHALENE
PENTACHLOROPHENOL
PHENANTHRENE
PHENOL
PYRENE
STYRENE
TOLUENE
TOTAL XYLENES
ALUMINUM
ARSENIC
BARIUM
BERYLLIUM
CADMIUM
CALCIUM
CHROMIUM
COBALT
COPPER
IRON
LEAD
MAGNESIUM
MANGANESE
MERCURY
NICKEL
POTASSIUM
SILVER
SODIUM
THALLIUM
VANADIUM
ZINC
CYANIDE

-------
                                   TABLE  3

                       Area-By-Area Review  of Possible
                           Causes  of Contamination
      Area

      Upper  Site Area

      Northeast Tank Area


      Process Area
      Excavated Lagoons
     Area

      Pond Area
!      Spray Irrigation Area

!      Land Treatment Area

!      West Tributary
Possible Causes of Contamination

    Drippage  from  treated wood during  storage.

    Drippage  from  treated wood during  storage.
   Leakage from tanks.

    Retort waste disposal practices.
   Raw material spillage.
   Drippage from treated wood during transport.
   Inadeguate housekeeping practices.

   Waste disposal  practices.
    Surface  drainage.
   Transport of contaminants from
   lagoons via groundwater.

    Spray  irrigation of  lagoon  supernatants.

    Land application of  lagoon  sludges.

    Run on from the on-site pond.

-------
                                     TABLE  4

           Summury  - Contaminated Soil Excavation Volume  Estimates
                     Southern Maryland Woodtreating  Site
                             Hollywood, Maryland

         AREA                                     ESTIMATED  VOLUMES  (C.Y.;

      A.  CONTAINMENT AREA  (1):                          62,300

      B.  LAND TREATMENT AREA  (2):                       11,000

      C.  NORTHEAST TANK AREA  (1):                       1,700

      D.  UPPER SITE AREA  (1):                             300

      E.  WESTERN TRIBUTARY  (1):                         2,000

      F.  EASTERN TRIBUTARY  (1):                           200

                                              TOTAL:     77,500    C.Y.

NOTE:

(1)    Hazardous Waste Remedial Action Predesign Report Vol.  1
       Dames & Moore, June 1992

(2)    EPA - ERT Analytical Report, August  1993

-------
TABLE 5

CHEMICALS OF CONCERN SELECTED
FOR THE SOUTHERN MARYLAND SITE
RISK ASSESSMENT IN THE
REMEDIAL INVESTIGATION
GROUND WATER
                                                NON-CARCINOGENIC PAHS
Toluene
Benzene
Ethylbenzene
Styrene
Total Xylenes
Phenol
2-methylphenol
4-methylphenol

2,4-Dimethylphenol
Pentachlorophenol
ncPAHs
cPAHs
Naphthalene
2-methylnaphthalene
Acenaphthylene
Acenaphthene
Fluorene
Phenanthrene
Fluoranthene
Pyrene

Benzo(g,h,i)perylene
                                                CARCINOGENIC PAHS
SEDIMENT

Toluene
Ethylbenzene
Total Xylenes
ncPAHs
cPAHs
Benzo(a)anthracene
Chrysene
Benzo(b) fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Indeno(1,2,3-cd)pyrene
Dibenzo(a,h)anthracene
SURFACE SOIL

Toluene
Ethylbenzene
Styrene
Total Xylenes
Pentachlorophenol
ncPAHs
cPAHs

COMBINED SOILS
Toluene
Ethylbenzene
Styrene
Total Xylenes
Pentachlorophenol
ncPAHs
cPAHs

-------
                                               TABLE 6

                               CONCENTRATIONS OF INDICATOR CHEMICALS
                                          IN GROUND WATER
                                    AT THE SOUTHERN MARYLAND SITE
CHEMICAL

TOLUENE
BENZENE
ETHYLBENZENE
STYEENE
TOTAL XYLENES
PHENOL
2-METHYLPHENOL
4-METHYLPHENOL
2,4-DIMETHYLPHENOL
PENTACHLOROPHENOL
ncPNAs
cPNAs
UNITS

ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
MAXIMUM
CONCENTRATION
900
1500
130
240
610
12000
14000
16000
8300
5000
93340
7900
GEOMETRIC
MEAN
5.67
6.38
6.74
8.43
7.20
12.3
22.7
20.6
27.0
54.3
142
68
FREQUENCY OF
DETECTION
13
14
6
5
11
20
14
11
16
12
106
24
/44
/44
/44
/44
/44
/47
/44
/44
/44
/44
/396
/308
                               CONCENTRATIONS OF INDICATOR CHEMICALS
                                           IN SEDIMENT
                                   AT THE SOUTHERN MARYLAND SITE
CHEMICAL
                            UNITS
                                          GEOMETRIC
                                             MEAN
                                MAXIMUM
                             CONCENTRATION
                                  FREQUENCY OF
                                    DETECTION
TOLUENE
ETHYLBENZENE
TOTAL XYLENES
ncPNAs
cPNAs
ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
2.28
4.03
4.47
3593
2589
   49
   37
   23
78860
21545
 3 /17
 2 /17

56 /153
29 /119

-------
                                                                  CONCENTRATIONS OF CHEMICALS OF CONCERN
                                                                                IN SOILS
                                                                    AT THE SOUTHERN MARYLAND SITE
                                           SURFACE  DEPTHS  (0.0.2.0  FT)
                                                                                                     SUBSURFACE DEPTHS
                                                                                                                                                    COMBINED DEPTHS
CHEMICAL

TOLUENE
ETHYLBENZENE
STYRENE
TOTAL XYLENES
PENTACHLOROPHENOL
ncPNAs
cPNAs
UNITS

ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
ug/kg
GEOMETRIC
MEAN
4.65
8.17
8.18
8.89
2071
8377
4295
MAXIMUM
CONCENTRATION
4600
8200
12000
14000
90000
154090000
1891500
FREQUENCY OF
DETECTION
8 /66
6 /66
7 /66
7 /66
8 /59
132 /531
78 /413
GEOMETRIC
MEAN
9.69
16.0
14.5
16.7
1519
6151
2496
MAXIMUM
CONCENTRATION
8100
10000
7200
35000
60000
4820000
392500
FEQUENCY OF
DETECTION
1 /15
3 /15
2 /15
2 /15
4 /16
34 /144
12 /112
GEOMETRIC
MEAN
5.32
9.25
9.10
10.0
1923
7776
3772
MAXIMUM
CONCENTRATION
8100
10000
12000
35000
90000
15960000
1891500
FREQUENCY OF
 DETECTION

   9 /81
   9 /81
   9 /81
   9 /81
  12 /75
 166 /675
  90 /525

-------
                                     TABLE 7

            ESTIMATED ANNUAL AVERAGE SURFACE WATER CONCENTRATIONS
                       AT THE SOUTHERN MARYLAND SITE

                          (Concentrations in mg/1)

                                                             Plausible
Chemicals of Concern                Average Case           Maximum Case

Benzene                               1.0x10-3                0.18
Toluene                               8.4x10-4                0.27
Ethylbenzene                          9.1x10-4                0.11
Stryene                               1.4x10-3                0.46
Xylene                                1.3x10-3                0.69
Phenol                                3.3x10-2                2.07
4-Methylphenol                        1.6x10-2                1.98
2-methylphenol                        2.8x10-3                1.72
2,4-Dimethylphenol                    1.7x10-2                1.03
Pentachlorophenol                     1.4x10-3                0.65
CPNAs                                 7.9x10-3                1.33
NCPNAs                                3.1x10-2               26.98
   CONCENTRATIONS OF GROUNDWATER BASED ON INFILTRATION MODEL
                AT THE SOUTHERN MARYLAND SITE

                                         Cgw  (ppm)  (a)
CHEMICAL                                AVG        MAX

TOLUENE
ETHYLBENZENE
STYRENE
TOTAL XYLENES
PENTACHLOROPHENOL
cPNAs                                 9.0E-06      4.5E-03

(a) Calculated using Kd for cPNAs = 38,400

-------
                                                TABLE  8

                          HEALTH EFFECTS CRITERIA FOR  CHEMICALS  OF  CONCERN
                                   AT THE SOUTHERN MARYLAND  SITE
CHEMICAL

TOLUENE
BENZENE
ETHYLBENZENE
STYRENE
TOTAL XYLENES
PHENOL
2-METHYLPHENOL
4-METHYLPHENOL
2,4-DIMETHYLPHENOL
PENTACHLOROPHENOL
ncPNAs
cPNAs
                          Cancer Potency Factor
                           (mg/kg/day)-1  (a)
                               Oral
0.052
                        Weight
                          of
                      Evidence  (b)
                          82
Reference Dose  (RfD)
  (mg/kg/day)  (c)
       Oral

        0.3

        0.1
        0.2
          2
       0.04
       0.05
       0.05
       0.05
       0.03
       0.41  (d)
                                 11.5  (e)
                          82  (f)
(a)  Oral cancer potency factors  (gl*) were deroved by EPA's Carcinogen Assessment  Group (EPA 1986)

(b)  Weight-of-Evidence classification for potential carcinogen.   See  text  for  description.

(c)  RfD promulgated by the RfD Work Group  (EPA 1986, 1987b,c).

(d)  The reference dose for noncarcinogenic PNAs is currently under  reanalysis  (EPA 1987a).
     For the risk assessment, the most recently accepted value will  be used.  This
     reference dose is for naphthalene.

(e)  The potency factor for carcinogenic PNAs is currently  under  reanalysis (EPA 1987a).
     For the risk assessment, the most recently accepted value will  be used.  This
     potency factor is for benzo(a)pyrene.
(f)  The Weight-of-Evidence used for cPNAs is that of benzo(a)pyrene  (EPA 1986).

-------
                                         TABLE 9

             ASSUMPTIONS USED TO ESTIMATE EXPOSURE TO TREAPSSERS VIA DIRECT
                  CONTACT WITH SOIL AND SEDIMENTS—CURRENT-USE SCENARIO
                              AT THE SOUTHERN MARYLAND SITE
Parameter

Frequency of exposure
Period of exposure
Incidental ingestiona
Oral absorption factorb
     cPNAs
     ncPNAs
     other nc
Daily soil contact ratec
Area of exposed skind
Dermal absorption factore
Average body weight
Exposure point concentrationsf
Average Case

2 days/year
5 years
50 mg/day

0.15
0.50
1.00
0.5 mg/cm2
1980 cm2
0.01
60 kg
geometric mean
Plausible Maximum Case

  5 days/year
  5 years
  100 mg/day

  0.45
  1.00
  1.00
  1.5 mg/cm2
  1980 cm2
  0.04
  60 kg
  maximum
a Based on the work of LaGoy 1987.
b This factor represents the percentage of contaminants absorbed from ingested soil.
c Based on the work of Schaum 1984.
d EPA 1985.
e This factor represents the percentage of contaminants absorbed through the skin.
f These concentrations are shown in Table 6.

-------
                                         TABLE 10

             ASSUMPTIONS USED TO ESTIMATE EXPOSURE TO TREAPSSERS VIA DIRECT
                  CONTACT WITH SOIL AND SEDIMENTS—CURRENT-USE SCENARIO
                              AT THE SOUTHERN MARYLAND SITE
Parameter

Frequency of exposure
Period of exposure
Incidental ingestiona
Oral absorption factorb
     cPNAs
     ncPNAs
     other nc
Daily soil contact ratec
Area of exposed skind
Dermal absorption factore
Average body weight
Exposure point concentrationsf
Average Case

264 days/year
0.25 years
50 mg/day

0.15
0.50
1.00
0.5 mg/cm2
1980 cm2
0.01
70 kg
geometric mean
Plausible Maximum Case

  264 days/year
  0.5 years
  100 mg/day

  0.45
  1.00
  1.00
  1.5 mg/cm2
  1980 cm2
  0.04
  70 kg
  maximum
a Based on the work of LaGoy 1987.
b This factor represents the percentage of contaminants absorbed from ingested soil.
c Based on the work of Schaum 1984.
d EPA 1985.
e This factor represents the percentage of contaminants absorbed through the skin.
f These concentrations are shown in Table 6.

-------
                                         TABLE 10

             ASSUMPTIONS USED TO ESTIMATE EXPOSURE TO TREAPSSERS VIA DIRECT
                  CONTACT WITH SOIL AND SEDIMENTS—CURRENT-USE SCENARIO
                              AT THE SOUTHERN MARYLAND SITE
Parameter

Frequency of exposure
     Children  (1-12 years)
     Adults  (12-70 years)
     Lifetime  (0-70 years)
Period of exposure
     Children aged 1-6 years
     Children aged 6-12 years
     Ages 12 and older
     Lifetime  (0-70 years)
Incidental ingestiona
     Children aged 1-6 years
     Children aged 6-12 years
     Ages 12 and older
     Lifetime  (0-70 years)
Oral absorption factorb
     cPNAs
     ncPNAs
     other nc
Daily soil contact ratec
Area of exposed skind
     Children aged 1-6 years
     Children aged 6-12 years
     Ages 12 and older
     Lifetime  (0-70 years)
Dermal absorption factore
Average body weight
     Children aged 1-6 years
     Children aged 6-12 years
     Ages 12 and older
     Lifetime  (0-70 years)
Exposure point concentrationsf
Average Case
125 days/year
25 days/year
50 days/year

5 years
6 years
58 years
70 years

100 mg/day
50 mg/day
25 mg/day
50 mg/day

0.15
0.50
1.00
0.5 mg/cm2

1730 cm2
2920 cm2
1980 cm2
2040 cm2
0.01

15 kg
30 kg
70 kg
60 kg
geometric mean
                                                                  Plausible Maximum Case
250 days/year
100 days/year
125 days/year

5 years
6 years
58 years
70 years

500 mg/day
250 mg/day
100 mg/day
140 mg/day

0.45
1.00
1.00
1.5 mg/cm2

1730 cm2
2920 cm2
1980 cm2
2040 cm2
0.04

15 kg
30 kg
70 kg
60 kg
maximum
a Based on the work of laGoy 1987.
b This factor represents the percentage of contaminants absorbed from ingested soil.
c Based on the work of Schaum 1984.
d EPA 1985 Adult values were calculated based on the exposure of the hands
  and forearms.  Children's values were calculated based on the exposure of
  the hands, lower legs and lower arms.
e This factor represents the percentage of contaminants absorbed through the skin.
f These concentrations are shown in Table 6.
g Lifetime values are weighted averages of values for different age groups

-------
                                   TABLE 12

      CHRONIC DAILY INTAKE AND POTENTIAL CANCER RISKS TO TRESPASSERSa
                       AT THE SOUTHERN MARYLAND SITE

                        Chronic Daily Intake         Excess Lifetime Cancer Risk
Media
                         Average     Maximum          Average         Maximum
                         Case        Case             Case            Case

Soil                     4-3x10-10   5.2x10-6         5.6x10-9        5.8x10-5

Sediment                                              3.4x10-9        6.6x10-7

a  The assumptions made in developing the average and plausible maximum
exposure cases are shown in Table 9.
                        Chronic Daily Intake         Excess Lifetime Cancer Risk
Media
                         Average     Maximum          Average         Maximum
                         Case        Case             Case            Case
Soil                     2 6x10-9    2.6x10-5         2.8x10-8        2.6x10-4
a  The assumptions made in developing the average and plausible maximum
exposure cases are shown in Table 10.

-------
                                   TABLE 12

      CHRONIC DAILY INTAKE AND POTENTIAL CANCER RISKS TO TRESPASSERSa
                       AT THE SOUTHERN MARYLAND SITE
Media
                        Chronic Daily Intake
                              (mg/kg/day)
                         Average
                         Case
            Maximum
            Case
                            Excess Lifetime Cancer Risk
                             Average
                             Case
                Maximum
                Case
Soil
  Children 1-6 yrs
  Children 7-12 yrs
2 x 10-7
1 x 10-7
  Ages 13 yrs and older  5 x 10-8

  Lifetime  (0-70 years)  1.7x10-7

Groundwater
            2 x 10-3
            1 x 10-3
            1 x 10-3

            8.7x10-4
2 x 10-6
1 x 10-6
6 x 10-7

2.0x10-6
2 x 10-2
1 x 10-2
1 x 10-2

2 x 10-2
  Lifetime-Actual
     Benzene
     CPNA
3 x 10-4
2 x 10-3
            5 x 10-2
            9 x 10-2
1 x 10-5
3 x 10-2
3 x 10-3
0.95
  Lifetime-Infiltration model
     CPNA                3 x 10-7
                                     2 x 10-4
                                                      3.5 X 10-6
                                                                      2 x 10-5
a  The assumptions made in developing the average and plausible maximum
exposure cases are shown in Table 11.

-------
                               TABLE 13

                        NONCARCINOGENIC RISKS

                   SOUTHERN MARYLAND WOOD TREATING
POPULATION              MEDIUM            AVERAGE       MAXIMUM
                                                        CASE                           CASE

TRESPASSERS             SOIL              8 X 10-4      2 X 10-3
                        SEDIMENT          5 X 10-8      1 X 10-5

CONSTRUCTION            SOIL              5 X 10-5      4 X 10-2

RESIDENTS               SOIL              1 X 10-5      6 X 10-2
                        GROUND WATER      1X10-1       50

-------
TABLE 14
Southern Maryland Wood Treatment Site
Summary risk matrix:  upper bound excess lifetime cancer risk

"--":  Exposure route not assessed
                  Remedial
                  Alternative                            Air
                                                    Soil      Groundwater

                                                    Risk to Residents
                                                                                              Total
1,2:  No action,  limited action
3:   Capping and containment
4:   Excavation, capping, and containment
5:   Excavation and off-site disposal
6:   Thermal treatment
7:   Thermal desorption
8:   ExcavaUon and on-site bioremediation (5 y)
8:   Excavation and on-site bioremediation  (10 y
9:   Bio-slurry
2.01E-07
1.44E-07
7.00E-07
2.42E-07
1.99E-07
2.20E-06
1.33E-05
1.33E-05
3.81E-07
7



9
9
8
1
3
.17E-04
-
-
-
. 60E-07
. 60E-07
.89E-05
.13E-05
.59E-05
-
-
-
-
8.77E-05
8.77E-05
1.42E-04
1.30E-05
3.26E-04
-
-
-
-
8.89E-05
9.09E-05
2.44E-04
3.76E-05
3.62E-04
                                                                     Risk to Workers
1,2:  No action,  limited action
3:   Capping and containment
4:   Excavation, capping, and containment
5:   ExcavaUon and off-site disposal
6:   Thermal treatment
7:   Thermal desorption
8:   Excavation and on-site bioremediation
8:   Excavation and on-site bioremediation
9:   Bio-slurry
                          (5 y)
                          (10 y
Source:
                                                   3.07E-05
4.12E-07
4.12E-07
4.12E-07
3.81E-06
4.86E-07
1.54E-06
Focused Human Health Risk Assessment, Risks After
Remediation for Nine Remedial Alternatives for the
Southern Maryland Wood Treating Site, Roy L. Smith,
Ph.D.,  U.S. EPA, November 17, 1994.

-------
TABLE 14
Southern Maryland Wood Treatment Site
Summary risk matrix:  upper bound excess lifetime cancer risk

"--":  Exposure route not assessed
                  Remedial
                  Alternative                            Air
                                                    Soil      Groundwater

                                                    Risk to Residents
                                                                                              Total
1,2:  No action,  limited action
3:   Capping and containment
4:   Excavation, capping, and containment
5:   Excavation and off-site disposal
6:   Thermal treatment
7:   Thermal desorption
8:   Excavation and on-site bioremediation
8:   Excavation and on-site bioremediation
9:   Bio-slurry
                          (5 y)
                          (10 y
0.
0.
0.
0.
0.
0.
o,
0.
0.
1472
1472
0447
0431
0429
0429
0429
0429
0429
1.
-
-
-
0,
0,
0,
0,
0,
.2536



.0017
.0017
.0516
.0065
.0626
-
-
-
-
2,
2,
0,
0,
8,




.3846
.3846
.9426
.1183
.7434
-
-
-
-
2
2
1
0
8




.4292
.4292
.0371
.1678
.8489
                                                                     Risk to Workers
1,2:  No action,  limited action
3:   Capping and containment
4:   Excavation, capping, and containment
5:   Excavation and off-site disposal
6:   Thermal treatment
7:   Thermal desorption
8:   Excavation and on-site bioremediation
8:   Excavation and on-site bioremediation
9:   Bio-slurry
                          (5 y)
                          (10 y
Source:
Focused Human Health Risk Assessment, Risks After
Remediation for Nine Remedial Alternatives for the
Southern Maryland Wood Treating Site, Roy L. Smith,
Ph.D.,  U.S. EPA, November 17, 1994.
                                                     0.4605
0.0062
0.0062
0.0062
0.0189
0.0024
0.0230

-------
                        TABLE 16
                    DELISTING LEVELS

CARCINOGENIC PAHs                   DELISTING LEVEL  (MG/L)

Benz(a)anthracene                   2 X 10-4

Benzo(b)fluoranthene                6 X 10-3

Benzo(k)fluoranthene                2 X 10-1

Benzo(a)pyrene                      1 X 10-2

Chrysene                            6 X 10-2

Dibenz(a,h)anthracene               1 X 10-4

Indeno(l,2,3-cd)pyrene              6 X 10-3

NON-CARCINOGENIC PAHs               DELISTING LEVEL  (MG/L)

Acenaphthene                        1 X 102

Anthracene                          6 X 102

Fluoranthene                        6 X 101

Naphthalene                         6 X 101

Phenanthrene                        1 X 10-1 *

Pyrene                              6 X 101

-------
                    TABLE 16  (cont'd)

                    DELISTING LEVELS
SEMIVOLATILE AROMATIC
HYDROCARBONS

p-Chloro-m-cresol

2-Chlorophenol

2,4-Dimethylphenol

2,4-Dinitrophenol

Carbazole

Pentachlorophenol

Phenol

2,3,4,6-Tetrachlorophenol

2,4,5-Trichlorophenol

2,4,6-Trichlorophenol
DELISTING LEVEL (MG/L)


1 X 101 *

1 X 101

4 X 101

4 X 100

2 X 10-1

6 X 10-2

1 X 103

6 X 101

2 X 102

5 X 10-1

-------
TABLE 16 (cont'd)

DELISTING LEVELS

VOLATILE AROMATIC DELISTING LEVEL (MG/L)
HYDROCARBONS

Benzene 3 X 10-1

Ethylbenzene 4 X 101

Styrene 6 X 100

Xylene 6 X 102

* HBLs for these compounds obtained from information provided by the Office of Solid Waste, Health
Assessment Section.

Treated soils will be analyzed using the EPA Method 1311 Toxicity Characteristic Leaching Procedure (TCLP).
The concentrations in the resultant extract must meet the delisting levels in the table above. Provided
these levels are achieved, the waste is delisted and the treated soils are no longer reguired to be managed
as hazardous waste.

Delisting levels = HBL x DAF

HBL = health-based level in drinking water at a hypothetical downgradient well. The HBLs
are found in Docket Report on Health-Based Levels and Solubilities Used in the
Evaluation of Delisting Petitions Submitted Under 40 CFR §260.20 and §260.22, U.S.
EPA, Office of Solid Waste, Waste Identification Branch, Delisting Section,
December 1994.

DAF = dilution attenuation factor calculated using the EPA Composite Model for Landfills
(CML) (See 56 FR 32993, July 18, 1991).

The exposure assumption that is used to assess the hazard of a petitioned waste is ingestion of contaminated
ground water, leachate, or wastewater. The EPA CML models what happens when waste is placed in a landfill,
leaching occurs, and contaminants are transported in ground water to a drinking water well.

-------
TABLE 17

CALCULATION OF BENZO(A)PYRENE EQUIVALENCE
SOUTHERN MARYLAND WOOD TREATING SITE
Carcinogenic Toxicity Concentration
PAH equivalence at 1 ppm
factor total CPAHsl
(mg/kg)
benzo (a) 1.0 0.06
pyrene
benzo (b) 0.1 0.07
fluoranthene
benzo(k) 0.01 0.07
fluoranthene
benz(a) 0.1 0.14
anthracene
carbazole 0. 003 0.46
chrysene 0. 001 0.20
TOTAL 1.00
Rounding
Benzo (a) pyrene Concentration Benzo (a)
eguivalence2 at 10 ppm pyrene
(mg/kg) CPAHs eguivalelece
(mg/kg) (mg/kg)
0.06 0.60 0
0.007 0.69 0
0.0007 0.72 0
0.014 1.4 0
0.0014 4.59 0
0.0002 2.00 0
0.0833 10.00 0
0.1 1
.60
.069
.0072
.14
.014
.002
.832
.0
     1 Concentrations from Table 49 of the Focused Risk Assessment

     2 Calculated by multiplying the concentration in mg/kg by the toxicity equivalence factor.

-------
                                                                              Table 18

                                                    Applicable or  Releevant  and Appropriate Requirements  (ARARS)
                                                               and Guidance  to Be Considered (TBCs)
                                                                    for  All Alternatives Evaluated
                                                            for the Southern  Maryland Wood Treating Site
                                 Legal Citation
I.  CHEMICAL
    SPECIFIC
                                             Applicability to Remedial Alternatives
A.  Water

1.  Safe Drinking Water  Act
    Maximum Contaminant
    Level Goals  (MCLGs)
    Clean Water Act;
    Federal Ambient Water
    Quality Criteria  for
    Protection of Aquatic
    Life
MCLs are enforceable  standards
for public drinking water
supply systems which  have  at  least  15
service connections or  are used by  at
least 25 persons.  These requirements
are not directly applicable since

ground water at the Site may be used
as a private drinking water supply.
However, under the circumstances of
this Site, MCLs are relevant  and
appropriate requirements.

MCLGs are non-enforceable  health
goals for public water  supplies which
have at least 15 service connections
or are used by at least  25 persons.
Under the circumstances  of this Site,
MCLGs are relevant and  appropriate
requirements.

These are non-enforceable  guidelines
established pursuant  to  Section 304  of
the Clean Water Act that set  the
concentrations of pollutants  which  are
considered adequate to  protect  aquatic
li fe.  Federal ambient  water  quality
criteria may be relevant and
appropriate to CERCLA cleanups
based on the uses of  a  receiving water
The NCP requires that  remedial  actions for
ground water that is a current  or potential
source of drinking water  shall  meet the
MCL for each site-related contaminant if the
Maximum Contaminant Level Goal  (MCLG)
for that contaminants  is  set  at a level of

and MCLs are relevant  and appropriate
under the circumstances of the  site.
The NCP requires that  remedial  actions for
ground water that is a current  or potential
source of drinking water  shall  meet non-zero
MCLGs for contaminants of concern for
which they exist, where they are relevant
and appropriate  requirements.
These criteria are relevant  and appropriate
because the State has  designated the on-site
stream for protection  of  aquatic li fe.
Contaminant concentrations in treated
ground water and surface  water that will be
discharged to the on-site stream shall  not
exceed the levels that will  ensure
compliance with these  criteria.

-------
Maryland Surface Water
Quality Criteria
5. EPA Health Advisories
on Drinking Water
6. Health Effects
Assessment
II. LOCATION
SPECIFIC
Legal Citation
Table 18

Class!fication

Applicable
To Be Considered
EPA Office of
Drinking Water
EPA Environmental Criteira
and Assessment Office
To Be Considered
Summary of Requirement

These are criteria to maintain surface
water quality for public water
supplies, protection of aquatic li fe,
recreational purposes, and other
beneficial uses.

IRIS is an EPA data base containing
up-to-date health risk and EPA
regulatory information for numerous
chemicals. IRIS contains only those
reference doses (FrDs) and cancer
slope factors that have been verified
by the RfD or Carcinogen Risk
Assessment Veri fication Endeavor
Workgroups, and is the preferred
source of toxicity information.

These advisories are non-enforceable
guidelines for public water supply
systems.
Applicability to Remedial Alternatives

Contaminant concentrations in treated
ground water and surface water that will be
discharged to the on-site stream shall not
exceed the Ivels that will ensure
compliance with these criteria.

These non-enforceable toxicity values shall
be considered where remedial alternatives
address risk-based criteria or when setting
standards for cleanups.
These advisories shall be considered for
remedial actions involving ground water
monitoring, recovery and treatment.

These assessments shall be considered where
remedial alternatives address risk-based
criteria or when setting standards for
cleanups.
B. The Archaeological and
Historical Preservation
Act of 1974
Applicable
Applicable
Act requires federal agencies to
ensure that any action author!zed by
an agency is not likely to j eopardi zed
the continued existence of any
endangered or threatened species or
adversely affect its critical habitat.

Requires actions to avoid potential
loss or destruction of significant
scientific, historical, or archaeological
data
Potentially affected endangered species have
not been identi fled. The remedial action
shall be implemented so as not to adversely
affect such resources should any be
identi fied in the future.
Actions shall be taken to mitigate any
adverse effects on identified historic
resources that might result from
implementation of the remedial action. No
historic resources have been identi fied to
date.

-------
E.
Maryland Wetlands
Regulations
Procedures for
Implementing the
Requirements of the
Council on
Environmental Quality
on the National
Act
Clean Water Act Dredge
and Fill Requirements
F. Ground Water Protection
Strategy of 1984
40 C.F.R Part
Appendix A
Table 18

Class!fication

Applicable

Applicable
33 U.S.C. Section 1344
40 C.F.R. Part 230,
33 C.F.R. Parts 320-330
(Army Corps)
Applicable
Summary of Requirement

Protects nontidal wetlands of the Site
from dredging, filling, removal, or
other alteration and requires State
oversight and approval.

This is EPA1s policy for carrying out
the provisions of Executive Orders
11990 (Protection of Wetlands) and
11988 (Flood plain Management)
Requires Federal agencies to avoid or
minimi ze adverse impacts of Federal
actions upon wetlands and
floodplains. If there is no other
practicable alternative, impacts must
be mitigated.

Regulates the discharge of dredged or
fill material to waters of the U.S.
Activities must minimi ze adverse
impacts and/or mitigate such impacts.

Identifies ground water quality to be
achieved during remedial actions
based on aquifer characteristics and
use .
Applicability to Remedial Alternatives

These regulations shall be applicable where
excavation, backfilling, and construction of
the cap or discharge to surface water affects
wetlands.

This shall be applicable where excavation of
contaminated soils and sediments,
construction of a cap, discharge of treated
surface water or ground water to surface
water, or backfilling of treated
soils/sediments affects wetlands or a
floodplain.
This shall be applicable where a cap is
placed over any wetlands onsite and where
any backfilling occurs in the pond or
tributaries.

The EPA classification of the aquifer at the
Site shall be taken into consideration during
post-remediation ground water monitoring.
Applicable
Requires remedial action to take into
account effects on properties included
in or eligible for the National Register
of Historic Places and to minimi ze
harm to National Historic Landmarks.
Actions shall be taken to mitigate any
adverse effects on property eligible for or
included on the National Register of Historic
Places that could result from implementation
of the remedial action.
III. ACTION SPECIFIC
Control of Noise
Pollution
Applicable
Maximum Allowable Noise Levels shall not
be exceeded at the site property boundaries
during construction and operation of the
remedy.
Water
1. Clean Water Act
National Pollutant
Discharge Elimination
Applicable
Establishes effluent limitations for
discharges to waters of the State and
controls discharge of toxic substances
to surface waters.
These limitations shall be applicable to the
discharge of treated ground water and
surface water to the receiving stream.
Actions must comply with only substantive
portions of the regulations.

-------
    Criteria and Standards
    for Best Management
    Practices
3.   Guidelines Establishing
    Test Procedures for the
    Analysis of Pollutants

4.   Regulation of Water
    Supply, Sewage Disposal
    and Solid Waste
Legal Citation

40 C.F.R. Part 125,
Subpart K
                                 40  C.F.R.  Part 136
            Table  18

Class!fication

Applicable




Applicable



Applicable
Summary of Requirement

Requires a clear description  of a best
management practices  (BMP)  program
to be submitted as part  of  the  NPDES
discharge permit application.

Establishes test procedures for
analysis of effluent  discharged under
the NPDES program.

Establishes requirements for  well
construction and abandonment.
Applicability to Remedial  Alternatives

Discharge of treated  ground  water and
surface water to the  receiving  stream shall
be in accordance with a  BMP  program,
although a permit is  not required.
                                                                                                            All wells  shall  be  installed and/or abandoned
                                                                                                            and maintained in accordance with State
                                                                                                            requirements  for construction and
                                                                                                            abandonment.
                                                                 Applicable
                                                                 Applicable
                                                                 Applicable
                                                               Requires development  of a stormwater
                                                               management  plan  and design and
                                                               construction  of  systems necessary to
                                                               control stormwater.

                                                               Requires approval  for water
                                                               appropriation when  volumes are such
                                                               that they may affect  water supply.

                                                               Requires preparation  of an erosion
                                                               and sediment  control  plan for
                                                               activities  involving  land clearing,
                                                               grading and other  earth disturbances
                                                               and establishes  erosion and sediment
                                                               control criteria.
                                                                            Stormwater shall be managed during and
                                                                            after construction to minimi ze stream
                                                                            channel erosion, pollution, sitation,
                                                                            sedimentation and local flooding.
                                                                            These regulations shall apply to clearing,
                                                                            grading,  excavation backfilling, and capping
                                                                            activities at the Site.
3.  Water Quality
    Certification
                                 Applicable
                               Establishes standards for certification
                               that activities do not violate state
                               water quality standards and
                               limitations.
                                             The water treatment  system  shall  be
                                             operated in accordance with this  regulation.
    Board of Well Drillers
                                                                 Applicable
                                                               Identi fies  general  regulations for well
                                                               drillers in the  State of Maryland
                                                                            Well  installation shall be performed by well
                                                                            drillers certified by the State of Maryland.
    Air
                                                                 Applicable
                                                               Establishes  requirements for process
                                                               vents associated with operations that
                                                               manage hazardous wastes with
                                                               organic  concentrations of at least 10
                                                               parts per million weight.
                                                                            These regulations shall apply to operation  of
                                                                            the  thermal treatment or thermal desorption
                                                                            units.

-------
                                                                              Table 18
    Air Emissions Standards
    for Equipment Leaks
    Maryland Regulations
    Governing Toxic Air
    Pollutants
4.   Maryland Regulations
    Governing Air Quality
    (Volatile Organic
    Compounds)
Legal Citation

40 C.F.R. Part 264,
Subpart BB
                                 Applicable
                                 Applicable
Summary of Requirement

Establishes standards  for  equipment
design criteria, work  practices,  and
specific emissions  limits  for TSD
facilities that contain  hazardous
wastes with more than  10%  by weight
total organics.

Requires emissions  of  Toxic  Air
Pollutants  (TAPs) from new and
existing sources to be quantified;
establishes ambient air  quality
              emission limitations  for
    emissions from  new sources;
requires best available  control
technology for toxics  (T-BACT)  for
new sources of TAPs.

Provides air quality standards, general
emission standards  and restrictions for
air emissions of VOCs  from vents  and
treatment devices that emit  in excess
of 20 Ibs/day VOCs.
                                                                                                                                             Applicability to  Remedial  Alternatives
                                                                            These regulations shall apply to  operation of
                                                                            the thermal treatment, thermal  desorption
                                                                            units,  or bioremediation treatment  units  of
                                                                            upon testing of the unit, TAP emissions  are
                                                                            detected.
                                                                            Emissions from thermal treatment,  thermal
                                                                            desorption,  or bioremediation units,  shall
                                                                            meet emission limitations  for VOCs.
    Maryland Regulations
    Governing Air Quality
    (Visible Emissions,
    Particulates, Nuisance)
                                 Applicable
                               Provide air quality standards,  general
                               emission standards and restrictions  for
                               visible emissions, particulates,  and
                               misances from vents and treatment
                               devices.
                                             These regulations  shall  apply to emissions
                                             from thermal treatment,  thermal  desorption,
                                             or bioremediation  units.
D.   Hazardous Waste
    Characteristics of
    Hazardous Waste
    (Toxicity, Ignitability,
    Corrosivity, Reactivity
    Characteristics) and
    Listed Wastes
COMARs 26.13.02.01-.14,
and .16-.19
(COMARs 10.51.02.01-.13,
and .15-.18  (1985) and
40 C.F.R. §261.24 and
261.31
Applicable
Establishes the criteria  for
determining if a solid waste exhibits
the characteristics  of toxicity,
ignitability, corrosivity,  or reactivity
or is a listed waste.
These criteria shall be  used in determining
whether soils, sediments and treatment
residuals are subj ect  to RCRA hazardous
waste regulations.
                                 COMARs 26.13.03.02, .03
                                 .04,  .05
                                 (COMARs 10.51.03.02, .03,
                                 .04,  .05 (1985))
                                 Applicable
                               Establishes requirements for a
                               generator who treats, stores or
                               disposes of hazardous waste on-site,
                               including packaging, labeling,
                               mani testing, and recordkeeping
                               requirements.
                                             Treatment residuals  or  soils  that contain
                                             listed hazardous wastes or  exhibit a
                                             characteristic of a  hazardous waste shall be
                                             managed onsite and prepared for offsite
                                             shipment according to these regulations.

-------
                                                                              Table 18
                                 Legal Citation
                               Summary of Requirement
                                             Applicability to Remedial Alternatives
    Standards for owners
    and Operators of
    Hazardous Waste
    Treatment, Storage, and
    Disposal Facilities
                                 COMAR 26.13.05.16-1
                                 (COMAR 10.51.01.16) and
                                 40 CFR Subpart X,
                                 §264.600-. 603
Applicable
Establishes performance  standards  for
owners and operators of  thermal
treatment devices that do  not
thermally destroy hazardous  wastes.
b.   Land Treatment
                                                                 Applicable
                               Establishes standards for owners and
                               operators of facilities that treat or
                               dispose hazardous waste in land
                               treatment units.
    Incinerators
                                                                 Applicable
                               Establishes regulations for hazardous
                               waste incinerators including
                               performance standards, operating
                               requirements,  monitoring and
                               inspection, and closure.
                                             These regulations apply to  thermal  treatment
                                             units defined as incinerators.
                                                                 Applicable
                               Establishes regulations for closure  and
                               post-do sure of hazardous waste
                               treatment,  storage, or disposal
                               facilities.
                                                                 Applicable
                                                                            Contaminated soil and treatment residues
                                                                            will  be stored in containers and/or tanks
                                                                            onsite prior to shipment offsite.  Soil
                                                                            washing and slurry phase bioremediation
                                                                            would be conducted in onsite containers
                                                                            and/or tanks.   Excavated soils and sediments
                                                                            may be placed in containers or tanks  for
                                                                            purposes of dewatering prior to treatment
                                                                            and following treatment before backfilling.
f.
    Surface Impoundments
     and Waste Piles
Applicable
Standards applicable to  treatment,
storage,  disposal of hazardous  wastes
in surface impoundments  and  waste
piles, respectively
Excavated soils and  sediments  may be
placed in a pile or  surface  impoundment for
purposes of dewatering prior to  treatment
and following treatment before backfilling.

-------
ARAR or TBC

g.   Landfills
                                 Legal Citation
            Table  18

Class!fication

Applicable
Summary of Requirement

Standards applicable to  the
construction, operation,  closure  and
post-do sure of landfills containing
hazardous waste
Applicability to Remedial Alternatives

Performance standards  apply to  the  multi-
layer cap, closure and post-do sure in the
capping alternatives,  and closure of the
landfills  (i.e., land  treatment area and
containment area) for  Alternatives  5-9.
                                                                 Applicable
4.  RCRA Land Disposal
    Restrictions
Applicable
Establishes standards  for
owners/operators to  institute  corrective
action as necessary  to protect human
health and the environment  for all
releases of hazardous waste  or
constituents from any  solid  waste
management unit

Restrictions on land disposal  of
hazardous wastes that  set
concentration levels or methods of
treatment that substantially diminish
the toxicity of wastes or reduce the
likelihood that hazardous constituents
from wastes will migrate from  the
disposal site.
                                                                            Corrective action would be instituted as
                                                                            necessary to protect human health and the
                                                                            environment from all releases of hazardous
                                                                            waste  or consitituents from any solid waste
                                                                            management unit that might result from
                                                                            instituting any of the alternatives.
Contaminated media to be  shipped offsite
for treatment and disposal  shall be
temporarily stored onsite,  analyzed,  and
treatment standards  determined in
preparation for shipment  in accordance with
these regulations.

-------
                              TABLE 19

             EPA CRITERIA FOR EVALUATING ALTERNATIVES

Threshold Criteria

Overall Protection of Human Health and the Environment:  Describes how the alternative, as a whole, achieves
and maintains protection each human health and the environment, and how risks posed through
each pathway are eliminate, reduced, or controlled through treatment, engineering controls, or institutional
controls.

Compliance with ARARs:  Addresses whether a remedy will meet all of the applicable or relevant and
appropriate reguirements (ARARs) of Federal and State environmental laws an/or justifies invoking a Waiver.

Primary Balancing Criteria

Long-Term Effectiveness and Permanence:  Considers the ability of the remedy no maintain reliable protection
of human health and the environment over time once clean-up goals have been met.

Reduction of Toxicity, Mobility, or Volume Through Treatment: Describes the anticipated performance of the
treatment technologies that may be employed in a remedy.

Short-Term Effectiveness:  Examines the effectiveness of alternatives in protecting human health and the
environment during the construction and implementation of the remedy, until the clean-up levels are achieved.

Implementability:  Evaluates the technical and administrative feasibility of alternatives and the
availability of reguired materials and services.

Cost:  Considers the capital and operation and maintenance (O&M) costs of the alternatives.

Modifying Criteria

State Acceptance:  Indicates whether the State agency, based on its review of the Proposed Plan, concurs
with, opposed, or has no comment regarding the preferred alternative.

Community Acceptance:  The community's general response to the alternatives will be assessed in the Record of
Decision following a review of the public ccmments received on the Administrative Record and the Proposed
Plan.

-------
SOUTHERN MARYLAND WOOD TREATING SITE
HOLLYWOOD, ST. MARY'S COUNTY, MARYLAND

RESPONSIVENESS SUMMARY

This Responsiveness Summary documents public participation in the remedy selection process for the Southern
Maryland Wood Treating Site  ("the Site")  and comments received by the U.S. Environmental
Protection Agency  ("EPA") during the public comment period on the Proposed Remedial Action Plan ("PRAP")  for
the Site.  It also provides EPA's responses to those comments.  The Responsiveness Summary is organized as
follows:

Section 1.0                   Overview

Section 2.0                   Background on Community Involvement

Section 3.0                   Summary of Major Comments Received During the
                              Public Comment Period and EPA' s Responses

1.0     OVERVIEW

On June 29, 1988, EPA issued a Record of Decision that established onsite incineration of contaminated
materials as the selected remedy for the Site.  Subseguently, community interest in the project grew and
local citizens and environmental groups expressed strong opposition to the operation of an incinerator in
their community.  In 1992, due to escalating costs in the design of the remedy and the Maryland Department of
the Environment's  ("MDE") inability to fund its reguired cost share, EPA halted the design of the remedy
selected in the 1988 ROD and agreed to reevaluate remedial alternatives for cleanup of the site in a Focused
Feasibility Study  ("FFS").

From approximately May 1992 to February 1995, EPA conducted the FFS where nine remedial alternatives were
developed and evaluated for their ability to address the contamination at the Site.  On March 21,  1995, EPA
released the PRAP which presented EPA' s preferred alternative for cleanup of the Site based on
information from the FFS.  The preferred alternative involved excavation of approximately 97,000 cubic yards
of soils and sediments that are contaminated with wood treating wastes and onsite treatment using a thermal
desorption technology.

EPA held a public meeting on March 30, 1995 to discuss the PRAP and to present its preferred alternative to
the community.  At this meeting, community members had an opportunity to ask guestions and make comments
regarding the results of the FFS, the risk assessment, and the cleanup alternatives listed in the PRAP. A
30-day public comment period was also held from March 22, 1995 to April 21, 1995.  As no significant comments
were submitted that would cause EPA to change its preferred alternative, EPA has
selected thermal desorption as the remedy for this Site.  A detailed description of the remedy is provided in
Section 10 of this Record of Decision.

The two most vocal community groups throughout the FFS process, the Southern Maryland Wood Treatment Plant
Task Force ("Task Force"), appointed by the St. Mary's County Commissioners, and the Environmental Awareness
Coalition of Southern Maryland  ("EAC"), a local citizens group, have submitted written
correspondence endorsing the selected remedy, thermal desorption, for this Site.  Both are opposed to no
action, incineration, and capping alternatives that would leave wastes in place.  Both groups have also
expressed the opinion that EPA should have put more effort into evaluating bioremediation technologies which
they believe might have been able to address the contamination at the Site with less impact to the community.
MDE has also endorsed the selected remedy.

2.0     BACKGROUND ON COMMUNITY INVOLVEMENT

Community interest in what became the Southern Maryland Wood Treating Site existed even before the wood
treating facility was built in 1965.  Nearby residents informally protested the construction of an industrial
facility on land which they had hoped would be used for residential purposes.  Once the facility was in

-------
operation, nearby residents complained to County officials of creosote-like odors coming from the Site.

EPA held its first public meetings on the Site in 1985 to explain short-term cleanup activities that were
being conducted during the first removal action and to discuss planned long-term work to be performed in a
Remedial Investigation and Feasibility Study ("RI/FS"). EPA conducted community interviews in 1986 and
developed a Community Relations Plan that described issues of community interest and outlined EPA activities
designed to facilitate citizen participation in the Superfund process during the RI/FS and beyond. When the
RI/FS was completed, EPA released a PRAP presenting eight cleanup alternatives. An article in the local
newspaper discussed the fact that EPA's preferred alternative involved onsite incineration of contaminated
soil. EPA then held a public meeting to discuss the PRAP. This meeting
was not widely attended. No opposition to the preferred alternative was expressed.

After EPA issued the Record of Decision on June 29, 1988, community interest in the Site grew. A new
citizens group, the EAC, was formed and the St. Mary's County Commissioners became increasingly involved due
to growing community concern with incineration and other aspects of the Site cleanup. The EAC
applied for a Technical Assistance Grant in order to hire a technical consultant and collected 2000
signatures on petitions reguesting that EPA reconsider the 1988 ROD. In July 1991, the County Commissioners
sent a letter to EPA reguesting that activities associated with incineration be suspended. The County
Commissioners had previously appointed the citizen Task Force to assess the Site cleanup.

In response to the high level of community concern about incineration, EPA issued fact sheets to provide
Site-specific information to the community and conducted further community interviews. EPA attended a County
Commissioners meeting in April 1991 and conducted several workshops on incineration in September
1991 to provide further information and address community concerns. The local residents in attendance
challenged EPA's assertion that mobile incineration was a safe and effective technology. At that time, EPA
agreed to continue to evaluate emerging innovative treatment technologies for their potential
applicability to the Site until the contract for the construction of the incinerator had been awarded. In
the following several months, the EAC and the Potomac River Association, another citizens group, continued to
voice their opposition to incineration, the Task Force met to discuss the remedy, and local media coverage of
the Site continued.

EPA, acknowledging both community interest in alternatives to incineration and State concern regarding cost
of the Site cleanup, asked EPA's Office of Research and Development ("ORD") to evaluate soil treatment
technologies potentially applicable to the Site. ORD conducted this evaluation and summarized its results in
a report dated February 3, 1992. This report, which was made available to the public, identified
incineration as readily available, and bioremediation as potentially applicable
to the Site. Finally, EPA announced in May 1992 that it would not move forward with the implementation of
the 1988 ROD and agreed to conduct the FFS to formally reevaluate Site cleanup options.

Additional community relations work performed in the months that followed revealed the community's major
concerns as the following: (1) community involvement in the decision making process; (2) assurance that EPA
was considering and adeguately evaluating all potentially applicable treatment technologies.

Throughout the FFS, EPA has maintained extensive community involvement in the process by offering regularly
scheduled conference calls involving the EAC, the Task Force, local media, and other interested parties. MDE
issued a series of written updates regarding the FFS and other Site activities. EPA has
periodically issued additional Fact Sheets containing updated site information, has conducted further
community interviews and Site tours for all interested parties, and has held numerous public meetings to
update the community of progress on the FFS and to receive comments. To address specific concerns of the
community on such topics as the integrity of the clay layer beneath the Site and the characterization of
dense non-agueous phase liguids ("DNAPLs"), EPA has held workshops where EPA experts on these topics have
given presentations.

All documents, including drafts of the FFS Work Plan and the FFS report, were made available to the public in
the information repository as they became available. Comments received from the public, primarily from the
Task Force and the EAC and its TAG advisor, were taken into consideration as these documents were
revised. In some cases, comments were addressed individually in separate documents. An entire remedial

-------
alternative for slurry-phase bioremediation was developed and evaluated in the FFS at the specific request of
the Task Force.  EPA also performed an onsite treatability study for solid-phase bioremediation.
Additionally, to assist EPA and the public in evaluating cleanup alternatives, EPA generated an innovative
post-remediation risk assessment which predicted risks that would be posed by the Site during and following
each of the alternatives evaluated in the FFS.  This risk assessment was also submitted to the public for
review and comment and discussed at a meeting with members of the Task Force and the EAC.

3.0     SUMMARY OF MAJOR COMMENTS RECEIVED DURING THE PUB1IC COMMENT PERIOD AND EPA'S RESPONSE

The responses to the comments received during the public comment period are divided into two categories,
those received at the public meeting and those submitted in writing.

A.  Comments Received at the Public Meeting

A transcript of the public meeting held March 30, 1995, is located in the Administrative Record file and is
available for public review at the Site repositories at the St. Mary's County library and at EPA's regional
office in Philadelphia.

Comment 1:  Several commenters expressed the concern that the inclusion of the word "containment" in the
titles of Alternatives 3 and 4, as described in the PRAP, is misleading.  They do not believe that the
natural clay layer beneath the Site can be relied upon to act as an effective containment mechanism to
prevent DNAPLs from migrating vertically into deeper drinking water aguifers and that to truly be considered
containment, these alternatives would have to include the installation of a RCRA-type liner as well as a cap.

With the current political climate of reducing government spending, the commenters' fear is that EPA may
select thermal desorption as the remedy for the Site, but that at some time in the future the selected remedy
might be changed to Alternative 3 or 4.   This is because, in the commenter's opinion, the PRAP is
written in such a way that these alternatives appear as protective of human health and the environment as
thermal desorption, but are estimated to be significantly less expensive to implement.

EPA Response:  It is EPA's position that the clay layer beneath the Site is an effective containment
mechanism based on data collected from several investigations conducted in the last several years and on
basic principles of DNAPL movement in the subsurface.  Data collected from numerous soil borings installed
throughout the Site indicates that the blue clay layer, which ranges from 19 to 23 feet thick, is continuous
in the area of the Site and that it will effectively act as a containment mechanism to prevent vertical
movement of contaminants in the ground water. The nature of the particular DNAPL material that is present at
this Site, creosote, is such that in order to provide enough pressure to drive the DNAPL into the small
capillary pores of the clay, much larger volumes of DNAPL would be required in the subsurface than have been
found in several wells within the containment area.  The vertical permeability of the clay has been
determined to be very low, in the range of 10-7 to 10-8 cm/sec. Additionally, data collected from four wells
screened in the sand unit beneath the clay have indicated that contaminants have not migrated through the
clay.  Based on ground water flow direction in that sand unit, the deep wells are located in the proper
positions to detect contaminants if they were present.  Data collected from these wells has not shown this to
be the case. See EPA Response to Comment 12, below, for further details on data results from these wells.

Alternatives 3 and 4 do not call for the creation or operation of a landfill.  They simply call for the
closure of an existing hazardous waste landfill, including the consolidation of hazardous wastes within an
area of contamination.  Therefore, EPA's RCRA interim status closure requirements would apply, but
not the minimum technology requirements ("MTRs") promulgated pursuant to the Hazardous and Solid Waste
Amendments of 1984  ("HSWA") (RCRA § 3004(o)) to which the commenter is apparently referring.  (MTRs apply to
new landfills and replacement of or lateral expansions of existing landfills.) The state of Maryland
also interprets its landfill closure regulations so that retrofitting the facility with new liners and
leachate collection systems would not be required.  However, the ground water monitoring program would be
used to monitor potential releases from the unit.  Both Alternatives 3 and 4 would meet EPA's and MDE's
closure and post-closure requirements.

With regard to some outside force changing the remedy for a Site from what has been selected in a ROD, EPA

-------
believes that this is unlikely to happen.  Moreover, this scenario is not consistent with the requirements of
the National Oil and Hazardous Substances Pollution Contingency Plan ("NCP") with respect to remedy
selection.  However, if such a situation did arise, it is unlikely that a decision would be made solely based
on the titles of the alternatives presented in the ROD without reading the descriptions of the alternatives.
The descriptions and the comparative analysis of alternatives provide a thorough explanation of the
components of each alternative and an evaluation of the strengths and weaknesses of each.  This includes the
position that EPA finds the Capping and Containment alternatives to be protective but that, relative to
thermal desorption, they are considered less protective and less desirable remedies for this Site.  To make
this distinction more clear, the text of the ROD has been modified somewhat from that which was found in the
PRAP (See Section 9.0 of the ROD).

Comment 2:  One commenter stated that the comparative analysis of alternatives in the PRAP did not clearly
state that Alternatives 3 and 4 provide less protection than EPA's preferred alternative. One commenter
expressed the opinion that the cost evaluation in the comparative analysis of alternatives should more
clearly state that although Alternatives 3 and 4 are less expensive than Alternative 7, they don't provide
the same level of protection. Another commenter suggested that the evaluation of the balancing criteria of
long-term effectiveness and permanence and reduction of toxicity could more clearly show that Alternative 7
is the better choice despite the lower cost of Alternatives 3 and 4.

EPA Response:  In Section 9.1 of the ROD, a statement has been added to the evaluation of overall protection
of human health and  the environment criterion to make it more clear that Alternatives 3 and 4 are considered
comparatively less protective than Alternatives 5-7 because contaminated media would remain onsite and
because they rely on institutional controls, in part, to provide protectiveness.  The cost evaluation in
Section 9.7 of the ROD has also been revised accordingly.

In the evaluation of the long-term effectiveness and permanence criterion in Section 9.3 of the ROD, the
discussion clearly states that Alternatives 3 and 4 afford a comparatively lesser degree of long-term
effectiveness than Alternatives 5 through 7 because they leave contaminated media onsite and rely on capping,
subsurface barriers and institutional controls to prevent future exposure rather than removing or treating
contaminated media.

Section 9.4 of the ROD, which evaluates the criterion of reduction of toxicity, mobility, or volume of
contamination through treatment clearly states that Alternatives 3 and 4 include essentially no treatment of
contaminated media compared to Alternatives 5 through 9.

Comment 3:  One commenter expressed the opinion that DNAPLs at SMWT could have moved through the clay layer
and that EPA has provided no detailed written analysis that could be peer reviewed to defend the position
that the DNAPL has not and could not move through the clay layer.

EPS Response:  Both EPA and MDE believe that the clay layer underlying the containment area prevents the
vertical migration of the creosote DNAPL present at the SMWT site.  This conclusion is supported by the
following data collected in numerous Site investigations and documented in the Administrative Record file
for the Site:  (1) the lateral extent and thickness of the clay layer as evidenced by numerous soil borings
conducted onsite;  (2) the physical characteristics of the clay (e.g., very low vertical
permeability of 10-7 to 10-8 cm/sec; (3) the depths of the DNAPL measured in the containment area (1 to 3
feet);  (4) chemical and physical characteristics of the creosote DNAPL (e.g., specific gravity, chemical
composition; and  (5) basic principles governing downward DNAPL migration and capillary pressures  (See DNAPL
Site Evaluation,  Robert M. Cohen and James W. Mercer, 1993, for a more detailed discussion).

To monitor whether site-related contaminants have migrated through the clay layer, EPA has installed four
monitoring wells in the sand unit just below the clay layer.  Based on data collected from these deep wells
(see EPA Response to Comment 12, below, for a further discussion of data), EPA has determined that
contaminants have not penetrated the clay.  Quarterly monitoring of these wells is ongoing.

Comment 4:  One commenter asked why EPA has established separate cleanup levels for soils and sediments.

EPA Response:  The subsurface soil cleanup levels were developed for protection of human health from exposure

-------
to ground water. The sediment cleanup levels were developed for the protection of aquatic life in the stream.

Comment 5: One commenter asked why the PRAP stated that the sediments "may" require remediation.

EPS Response: The ROD clearly states that sediments in the pond and tributaries with contamination above the
established cleanup levels will be dredqed and treated.

Comment 6: One commenter asked whether silt control measures will be implemented durinq excavation of the
sediments.

EPA Response: State of Maryland erosion and sediment control requlations found in COMAR 26.09.01.04-.07 and
.11 are listed as ARARs in Table 18 of the ROD. These requlations require preparation of an erosion and
sediment control plan for activities involvinq such thinqs as excavation and establish erosion and sediment
control criteria. These requlations will be complied with durinq implementation of the remedial action.

Comment 7: Commenters asked why there are no ARARs associated with the no action alternative and asked
whether it is possible for EPA to leave the Site as it currently exists if no further remedial action were
taken to address contaminated media. Since EPA has already taken some actions at the Site, such as
installinq the sheet pile wall and installinq monitorinq wells, one commenter asked if EPA would have to
perform such tasks as abandoninq the wells and removinq the sheet pile wall and consequently comply with any
ARARs associated with these actions, even if a no-action remedy were selected. Another commenter
asked why chemical-specific ARARs relatinq to qround water would be associated with Alternative 2 but not
with Alternative 1 when the alternatives are so similar.

EPA Response: Section 300.430 (e) (6) of the NCP states that at every site "the no-action alternative, which
may be no further action if some removal or remedial action has already occurred at the site, shall be
developed" in the feasibility study alonq with other alternatives that include takinq some remedial action.
In this case, since several actions have already been taken at the Site, Alternative 1 should more correctly
be titled No Further Action. This alternative is developed as a baseline to compare
with the other alternatives developed in the feasibility study. Accordinq to the document "Guidance for
Conductinq Remedial Investiqations and Feasibility Studies Under CERCLA," EPA/540/G-89/004, actions to reduce
the potential for exposure (e.g., site fencing, institutional controls) are not to be included in this
alternative, but monitorinq may be included. Monitorinq, the only component of the No Further Action
alternative for thisSite, is not a remedial action (i.e., an action to reduce the potential for exposure).
Accordinq to CERCLA §121(d) (2), ARARs have to be complied with only if a remedial action is selected
for the Site. Since no selected remedial action is associated with the no action, or no further action
alternative, there are no ARARs with which to comply.

If EPA selected no further action for this Site, any activities conducted onsite (e.g., monitorinq well
abandonment, dismantlinq of the water treatment system, or removal of the sheet pile wall) would be performed
as closeout activities pursuant to previous decision documents or removal actions, not pursuant to the new
ROD. Therefore, no ARARs would be associated with the no further action alternative because no new remedial
actions would be conducted.

Because Alternative 2 includes no actions to remediate qround water, MCLs or other risk-based chemical
specific ARARs related to qround water should not have been identified in the PRAP.

This correction has been included in the ROD in Section 8.0, Description of Alternatives and in the
evaluation of compliance with ARARs in the comparative analysis of alternatives in Section 9.2 of the ROD.
The PRAP stated that since Alternative 2 did not meet the threshold criterion of compliance with ARARs, it
would not be evaluated further in the comparative analysis of alternatives. This statement has been removed.
Further, in the evaluation of overall protection of human health and the environment (Section 9.1 of the ROD)
Alternative 2 is now described as beinq not protective and is not evaluated further in
the comparative analysis of alternatives for this reason.

Comment 8: One commenter questioned why no continqency is built into the remedy that would require a qround
water remedial action should the monitorinq show unacceptable concentrations of contaminants in the qround

-------
water.

EPA Response: Section 11.0 of the ROD, Ground Water Contingency, includes provisions for further measures to
be taken should the post-remedial ground water monitoring data show that contaminants remain at unacceptable
levels in the ground water. Such measures might include modification of cleanup levels or institutional
controls, ARARs waivers, and/or evaluation of remedial technologies for ground water restoration. The
decision to invoke any or all of these measures may be made by EPA, in consultation with MDE, at any time,
including during policy reviews of the remedial action which will be conducted at least
every five years from completion of construction of the remedial action. Any such changes to the remedy
described in the ROD will be made in accordance with procedures reguired by CERCLA and the NCP.

Comment 9: One commenter referred to the section in the PRAP on the nature and extent of contamination in
surface water and sediment and asked for further explanation of the phrase "very little contamination is
flowing from the pond via surface water due to the underflow dam installed during the most recent removal
action". More specifically, the commenter asked what is meant by "very little", and on what data this
determination was based.

EPA Response: The most recent surface water sample collected from the west tributary just outside the sheet
pile wall in September 1994, contained only 0.011 ppm volatile organic contaminants. No semivolatile
contaminants, which include the PAHs, were detected. These concentrations are very low relative to
contaminant concentrations found in the ground water and surface water of the pond within the sheet pile
wall. Contaminant concentrations in the upper reaches of the onsite pond are relatively high (> i ppm PAHs)
and in the ground water are as high as 31 ppm PAHs.

Comment 10: One commenter asked why the water treatment system constructed during the 1994-95 removal action
could not be operated even though final testing results had not been received which would determine whether
the treated water meets the reguired discharge standards established by the State of Maryland.

EPA Response: In accordance with the NCP §300.415(h)(i), removal actions at Superfund sites are reguired to
comply with ARARs to the maximum extent practicable given the exigencies of the situation. In order to
discharge treated water to the west tributary, the treated water must be in compliance with the effluent
limitations established by the state of Maryland pursuant to the Clean Water Act National Pollutant Discharge
Elimination System (NPDES). At the time of the public meeting on March 30, 1995, EPA had not yet received
the data which would prove that the treated water met these limitations; therefore, the water treatment
system could not be operated. That data has since been reviewed and approved by the State and the system has
commenced operation.

Comment 11: One commenter referred to the section in the PRAP on the nature and extent of contamination in
several deep monitoring wells and asked if the statement "sampling events conducted during 1994-95 indicate
that four monitoring wells outside of the sheet pile wall and screened in the sand unit just below the clay
layer are free of site-related contamination" meant that contaminants were found in the wells but were not
site-related or that no contaminants were found.

EPA Response: See response to comment 12, below.

Comment 12: Two commenters suggested when discussing the wells screened below the clay layer that language
should be included in the ROD to indicate that contamination had been found in these wells during one of the
guarterly rounds of ground water sampling, though subseguent sampling results show no contamination.

EPA Response: Section 5.2.2 of the ROD states that contamination (PAHs and phthalates) was found in the deep
wells during the March 1994 sampling event but that this may be due to cross-contamination of the samples
from airborne contamination resulting from excavation activities conducted onsite simultaneously with that
sampling event. In all subseguent sampling events, no site-related contaminants have been detected. Only one
phthalate compound, which is not site-related, has been detected. This compound, di-n-butylphthalate, is
often introduced during sampling and laboratory analysis because it is a component of plastics and
detergents.

-------
Comment 13:  One commenter asked whether EPA has identified the Site, including the area outside of the sheet
pile wall, as an Area of Contamination  (AOC) as this would affect the determination of ARARs for Alternative
4 where contaminated soil would be excavated and placed within the sheet pile wall.

EPA Response:  The Preamble to the NCP 40 CFR Part 300 (Federal Register Vol. 55, No.46, pp. 8758-8760, March
8, 1990) eguates an Area of Contamination (AOC), consisting of continuous contamination of varying amounts
and types at a CERCLA site, to a single RCRA land disposal unit, and states that movement within a
unit does not constitute placement.  Without placement, RCRA land disposal restrictions (LDRs)  would not
apply.  As stated in Section 8.0 of the ROD, EPA has designated the Site as an AOC. Therefore,  any movement
or consolidation of materials conducted onsite pursuant to these alternatives would not trigger these RCRA
regulations and, as a result, they were not identified as ARARs for such activities.

comment 14:  One commenter referred to the PRAP discussion of ARARs for Alternative 7, thermal desorption,
and asked for an explanation of the statement "The operation of the thermal desorption unit would be in
compliance with RCRA regulations for owners and operators of hazardous waste treatment, storage and
disposal facilities, specifically those associated with operation of a thermal treatment device other than an
enclosed type that uses controlled flame combustion."

EPA Response:  For clarity, the ROD includes revised text which states that the operation of the thermal
desorption unit will be in compliance with regulations that apply to thermal treatment units that are defined
as miscellaneous units  (COMAR 26.13.05.16-1 and 40 CFR Subpart X, §264.600-.603).

Comment 15:  One commenter referred to the process of delisting wastes and asked for an explanation of the
process EPA used to determine which contaminants would be included in the delisting and the process EPA used
to establish the delisting levels  (i.e., the concentrations of contaminants which will have to be met
through the treatment process).

EPA Response:  A March 21, 1995, memorandum from David M. Friedman, EPA RCRA Program, to Stephanie Dehnhard,
EPA Remedial Project Manager, which was added to the Administrative Record file for the Site during the
public comment period, documents EPA's process for determining the contaminants which will be
delisted and their corresponding delisting levels.  A copy of this memorandum was also submitted to the
commenter during the public comment period.

Comment 16:  One commenter asked if land use restrictions are included in any of the alternatives and whether
they will be imposed on the Site following completion of the selected remedy.

EPA Response:  In the description of alternatives in the ROD, land use restrictions are included in
Alternative 2 to preclude access to the Site, and in Alternatives 3 and 4 to protect the integrity of the
cap.  Alternative 5 does not include land use restrictions since all wastes would be removed from the Site.
Alternatives 6 through 9 do not include permanent land use restrictions since these alternatives include
remediation of contaminated media.  However, temporary land use restrictions would be imposed to prohibit
ground water use until it was demonstrated that MCLS or other risk-based chemical specific
ARARs had been achieved.  The cleanup levels are based on protection of human health and the environment;
therefore, no permanent land use restrictions would be needed.  Provided the cleanup levels are achieved
through implementation of the selected remedy (Alternative 7), no permanent land use restrictions will be
necessary.

Comment 17:  One commenter pointed out that the PRAP states that the Hazard Index  ("HI") associated with
ground water that was predicted in the post-remedial risk assessment for Alternatives 6 and 7,  is slightly
above 1 based on a subsurface soil cleanup level of 1 ppm benzo(a) pyrene ("BAP") eguivalents.   The
commenter guestioned why EPA would not excavate and treat this soil since the risk is above the HI of 1, the
threshold above which EPA would normally take an action.   Another commenter pointed out that the HI was
actually 2.4, which in his opinion was more than slightly above 1.

EPA Response:  The Hazard Index of 2.4 is the predicted risk from exposure to ground water that might result
from soil containing concentrations at the established subsurface cleanup level, not from soil exposure.  The
Hazard Indices associated with exposure to soil with concentrations of contaminants at the established

-------
cleanup levels were well below 1 for all alternatives.

When developing the cleanup levels for the Site and performing the post-remediation risk assessment, EPA
evaluated the concentrations of contaminants in the Site soil that could reasonably be expected to be
achieved by the technologies evaluated in the FFS. EPA then used a model, the Multimed model, to predict the
ground water concentrations that would result from the predicted soil concentrations. The risk assessment
then used those concentrations to predict the risk associated with exposure to ground water.

The HI of 2.4 is actually associated with exposure to the highest ground water concentrations that could
conceivably result from untreated soil left in the ground beyond the edge of the excavation area, an amount
that is expected to be a minimal volume of soil. EPA expects that the thermal desorption process
which will treat the much larger volume of excavated soil will reduce the non-carcinogenic contaminant
concentrations below the predicted levels because these compounds are relatively volatile and easily removed
by thermal treatment. lower soil concentrations would then translate into lower ground water
concentrations based on the reduction in constituents leaching into the ground water from the soil. This, in
turn, leads to lower risk associated with ground water exposure.

EPA has discretion in determining when it is appropriate to take remedial action at a site. Generally, the
threshold for non-carcinogenic risk is a Hazard Index above 1. In this case, though the ground water HI was
greater than 1, EPA determined that it was not necessary to lower the subsurface soil cleanup
level for the following reasons: (1) the ground water concentrations are predicted values based on a very
conservative model, not on actual data which will not be available until after the soil is remediated and the
ground water is sampled and analyzed; (2) the thermal desorption treatment process is expected to reduce
non-carcinogenic contaminants in the soil well below those predicted in the model, thus, reducing ground
water concentrations and associated risk: and (3) the difference between a HI of 1 and HI of 2.4 is actually
very small because the reference dose for a non-carcinogen can incorporate several orders of magnitude of
safety. The reference dose is the concentration of a chemical that is considered a safe dose. To calculate
risk, the assumed dose is compared with the reference dose.

Finally, the selected remedy includes ground water monitoring following the soil remediation and
institutional controls temporarily restricting the use of ground water from the shallow aguifer until EPA, in
consultation with MDE, determines that MCLs or other risk-based chemical specific ARARs are achieved. As
discussed in EPA's response to Comment 8, above, the selected remedy also provides a contingency for further
ground water evaluation and/or remedial action if necessary. Any necessary changes to the remedy described
in the ROD will be made in accordance with procedures reguired by CERCLA and the NCP.

Comment 18: One commenter asked if EPA had established a soil cleanup number for non-carcinogenic
contaminants and stated that at most wood treating sites, cleanup standards are established for total PARs
which would include the non-carcinogenic PAHs.

EPA Response: EPA has not established soil cleanup levels for non-carcinogenic PARs for the SMWT site. The
cleanup levels are based on carcinogenic PAHs because these contaminants contribute the greatest amount of
risk from exposure to Site media and are the most difficult to treat. The cleanup levels are expressed in
terms of benzo(a)pyrene (BAP) eguivalents because BAP is among the most toxic of the carcinogenic PAHs. EPA
believes that if the cleanup levels are achieved for the carcinogenic PAHs, then
the non-carcinogenic contaminants will be present at levels that are also protective of human health and the
environment.

Comment 19: One commenter expressed the opinion that the carcinogenic risk associated with ground water for
Alternative 7, as predicted in the post-remedial risk assessment (9 x 10-5), is a high residual risk. The
commenter guestioned whether EPA's established cleanup levels are adeguate and suggested that
perhaps the Site should be capped following remediation to prevent water infiltration and leaching of
residual soil contamination into the ground water.

EPA Response: The predicted post-remedial carcinogenic risk of 9 x 10-5 for ground water in Alternative 7,
the selected remedy, is within the acceptable risk range of 10-6 to 10-4 as established in the NCP
§300.430(e) (2) (i) (A) (2). Thus, the established subsurface cleanup level is adeguate and capping is not

-------
necessary. As stated in EPA's response to Comment 17, the modeling performed to predict ground water
concentrations is extremely conservative. Actual ground water concentrations and associated risks are likely
to be lower than predicted. Ground water monitoring following remediation of soils is included in
the selected remedy.

Comment 20: One commenter expressed the opinion that the evaluation of costs is not adeguate because
Alternative 4 does not include the costs associated with the impact of land disposal restrictions ("LDRs") or
with the installation of a liner and a leachate collection system. The commenter suggested that the
ARARs associated with this alternative need to be revised and that the associated costs should be included in
the cost evaluation.

RPA Response: As stated in EPA's responses to Comments 1, 2 and 13, above, RCRA LDRs are not ARARs for
Alternative 4, nor are the RCRA liner and leachate collection system regulations. The cost estimate in the
FFS and cost evaluation in the comparative analysis are therefore accurate.

B. Written Comments Received Before the Public Comment Period

On December 1, 1994, EPA attended a meeting held by the St. Mary's County Task Force. The purpose of the
meeting was to discuss the EPA' s Draft Focused Feasibility Study that had been released for public review on
November 14, 1994. At that meeting, when asked by the Task Force which remedial alternative EPA believed to
be the most appropriate for the Site at that time, EPA representatives in attendance stated unofficially that
Alternative 7, thermal desorption, appeared to be the best choice and that the forthcoming PRAP would likely
include that as EPA's preferred alternative. Subseguently, EPA received correspondence from the St. Mary's
County Commissioners and the EAC in response to the possibility that thermal desorption would in fact be
EPA's preferred remedy. These comments were received before the PRAP
was issued and the public comment period opened.

Comment 1: The EAC expressed strong opposition to the capping alternatives (Alternatives 3 and 4). The Task
Force commented that the titles of these alternatives should not include the word "containment" because they
do not provide a true containment mechanism but rely on the natural clay layer to contain
contaminants.

EPA Response: EPA did not choose either of the capping alternatives as the selected remedy for the Site.
EPA's position on the integrity of the clay layer beneath the Site, its ability to act as a containment
mechanism, and the protectiveness of these alternatives is discussed in the response to Comment 1 of
Section A of this Responsiveness Summary.

Comment 2: Both the Commissioners and the EAC endorsed the thermal desorption alternative dependent on the
following factors: (1) that the system be "closed loop" and indirectly fired; and (2) that the potential for
emissions containing vaporized heavy metals and products of incomplete combustion
("PICs") escaping from the system must be adeguately addressed. The EAC expressed a particular concern with
the presence of mercury in the soil.

EPA Response: In the ROD, EPA has chosen Alternative 7, thermal desorption, as the selected remedy for the
Site. The ROD includes general performance standards and ARARs which will be complied with during the
implementation of the remedial design and remedial action. During the remedial design, EPA will
determine more detailed specifications for the design of the thermal desorption unit that will be used at the
Site to meet those performance standards. Throughout this phase, EPA will continue to work closely with the
community to ensure that community concerns, such as those mentioned above, are factored into the design of
the remedy as appropriate.

Comment 3: The EAC and the Commissioners expressed disappointment with the guality of work that went into
creating the FFS, especially the bioremediation treatability study. The EAC also expressed a concern with
the DNAPL characterization.

EPA Response: EPA conducted the FFS and presented the FFS report in accordance with EPA guidance relating to
the RI/FS process. Several draft versions of the FFS report were released for public review and comment.

-------
Revisions to the document incorporated changes in accordance with public comments as EPA deemed
appropriate.

EPA believes the bioremediation treatability study performed during the FFS provided useful information with
regard to the implementation of bioremediation at the Southern Maryland Wood Treating Site. However, the
results of that study, combined with other available information on bioremediation, did not
demonstrate that this technology was the best alternative for remediation at this Site. Therefore,
bioremediation was not chosen as the selected remedy for this Site.

As explained in EPA's response to Comment 1 in Section A of this Responsiveness Summary, EPA believes that
the clay layer and DNAPL movement through it, have been adeguately characterized in the numerous studies
conducted at the Site. Available information allowed EPA to determine that contamination has not
penetrated the clay layer and to evaluate the alternatives in the FFS against all evaluation criteria.

Comment 4: The EAC commended EPA and MDE for their efforts to improve community involvement during the FFS.

EPA Response: As explained in Section 2.0, above, EPA made every effort to keep the community informed of
activities related to the Site and to take community input into consideration during the decision-making
process. EPA will continue to work with the community throughout the remedial design and remedial action
phases of the cleanup. Following issuance of the ROD, the Community Involvement Plan will be revised as
appropriate to determine the best way to maintain communication between EPA and the community.

Comment 5: The EAC and the Task Force stated that contaminated soil should be remediated adeguately to
preclude the State from being reguired to perform and pay for any related long-term operation and
maintenance.

EPA Response: In the ROD, EPA has established delisting levels for Site contaminants (see Section 8.0 of the
ROD). Following treatment by thermal desorption, if the concentrations of contaminants in the soil have met
these levels, the soil can be placed back onsite from where it was excavated. No long-term O&M
will be reguired for the backfilled treated soil.

Comment 6: The Commissioners stated that the Site must be left in a condition that will allow it to be used
productively following remediation (i.e., the cleanup levels must be adeguate to protect human health and the
environment) .

EPA Response: The cleanup levels established in the ROD are based on protection of human health and the
environment.

Provided these levels are achieved through implementation of the selected remedy, no permanent land use
restrictions will be reguired. The remedy includes temporary institutional controls to restrict ground water
use in the shallow aguifer onsite following soil remediation until EPA determines that the ground
water is safe to drink (i.e., until MCLs or other risk-based levels have been achieved).

C. Written Comments Received During the Public Comment Period

The only written comments received during the public comment period were submitted by the Maryland Department
of the Environment.

Comment 1: Because the selected remedy is a source treatment that does not directly address the issue of
ground water contamination, MDE will agree to monitor the ground water for a maximum of five years. If,
after five years, ground water contamination exceeds the MCLs or other risk-based chemical-specific ARARs,
MDE believes EPA should review the selected remedy and take appropriate actions to address ground water
contamination.

EPA Response: While it is true that the selected remedy does not specifically provide for treatment of
contaminated ground waterin order to achieve cleanup levels, EPA believes that the removal and treatment of
contaminated soils, sediments and NAPLs will result in the reduction of contaminant concentrations in the

-------
ground water.

The selected remedy includes provisions for a ground water monitoring program following soils and sediment
remediation. Also included is a provision for institutional controls to restrict ground water use in the
shallow aguifer onsite until EPA, in consultation with MDE, determines that the water is safe to drink.
While EPA believes that the treatment of the contaminated soils and sediment will result in the reduction of
contaminant concentrations in the ground water, it is difficult to predict exactly when the concentrations
will be reduced to acceptable levels across the Site.  Thus, the ROD does not specify an exact time at which
ground water monitoring will cease.

To address the possibility that ground water may remain contaminated for a long or indefinite period of time
following the remedial action, Section 11.0 of the ROD provides a ground water contingency.  This provision
will allow EPA to evaluate ground water data on a continuing basis, but not less often than
every five years after the completion of construction of the remedial action, and to take any of the
following measures:   (1)  modify cleanup levels or waive ARARs;  (2) modify or maintain institutional controls
to restrict access to those portions of the aguifer where contamination is above safe levels; and (3)
evaluate remedial technologies for ground water remediation.  Any such changes to the remedy described in the
ROD will be made in accordance with procedures reguired by CERCLA and the NCP, and in consultation with MDE.

EPA is reguired by CERCLA to review remedial actions not less often than every five years for as long as
hazardous substances remain on site and prevent unlimited use and unrestricted exposure at the site.  While
EPA intends to conduct these reviews, it does not believe that it is appropriate at this time
to limit the period of ground water monitoring to five years; since, as noted above, there are a variety of
measures that EPA may select based on the information evaluated during these five year reviews.

Comment 2:  The Proposed Plan states that the volume of soil to be excavated is approximately 78,000 CY. MDE
points out that it is more accurate to say that the volume of soil to be excavated and treated is 97,000 CY
due to swelling during excavation.

EPA Response:  This issue has been addressed in Section 5.3 of the ROD where it is explained that
approximately 78,000 CY of soil and sediment will be excavated and that when a swell factor
of 1.25 is applied, this volume increases to 97,000 CY of media to be treated following excavation.

Comment 3:  The ROD should indicate that all NAPL and grossly contaminated soil collected during excavation
will be shipped offsite for treatment and disposal.

EPA Response:  Sections 8 through 10 of the ROD discuss the fact that all NAPL and grossly contaminated soil
collected during excavation that is not amenable to treatment by thermal desorption will be shipped offsite
for treatment and disposal.

Comment 4:  To be more complete when discussing the analytical results for surface water and sediment
samples, it may be helpful to include the date that the samples were collected, as well as including data
results from the background sample collected from the east tributary.

EPA Response:  The Proposed Plan included a brief summary of Site characteristics.  Section 5 of the ROD
provides a more lengthy discussion of Site characteristics to provide the reader with a summary of the data
that has been collected to date, though it does not include every detail of all the studies that have been
conducted in the last several years.  Further details and all relevant documents containing Site
characterization information are available for public review in the Administrative Record file.

Comment 5:  It is indicated in the Delisting of RCRA Hazardous Wastes section of the Proposed Plan that
pursuant to "40 C.F.R. Section 260.22, that if, after treatment, concentrations of hazardous constituents are
below the delisting levels as set forth in Table 2, the soil can be delisted."  Please change this
sentence to read "after treatment, concentrations of hazardous constituents are below the delisting levels as
set forth in Table 2, the soil can be backfilled onsite".  As stated in paragraph one, MDE and EPA do not
view the soil as a hazardous waste due to the presence of the listed constituent.  After treatment has been
completed, the amount of listed constituent remaining in the soil will have been reduced to the point that it

-------
may be administratively delisted by the EPA.  Once the delisting process is completed the soil media,  which
was never considered to be a solid waste and was only being "managed as a hazardous waste due
to a listed constituent", may be reused onsite.

EPA Response:  Section 8 of the ROD discusses delisting of RCRA hazardous wastes and states that the
hazardous wastes in the soil, not the soil itself, will be delisted.  EPA agrees that the soil is not a
hazardous waste but must be managed as such because it is contaminated with RCRA hazardous wastes.

Comment 6:  When discussing Alternatives 8 and 9 please explain more thoroughly how contaminants "may become
more strongly bonded to the soil particles", reducing the chance of them leaching into the ground water.

EPA Response:  The referenced statement has not been included in the ROD.

-------
MARYLAND DEPARTMENT OF THE ENVIRONMENT
2500 Broening Highway ! Baltimore, Maryland 21224
(410) 631-3000

Parris N. Glendening Jane T. Nishida
Governor Secretary
September 5, 1995
Mr. Thomas Voltaggio, Director
Waste Management Division
U.S. Environmental Protection Agency
Region III
841 Chestnut Building
Philadelphia PA 19107

Re: Record of Decision Southern Maryland Wood Treating Site,
Hollywood, St. Mary's County, MD

Dear Mr. Voltaggio:

The Maryland Department of the Environment (MDE) has worked with the U.S. Environmental Protection
Agency (SPA) and the St. Mary's County community on the Southern Maryland Wood Treating site for a
number of years. MDE feels that remedial action at the site is long overdue.

MDE has reviewed the Proposed Remedial Action Plan (PRAP), and the Draft/Final Record of Decision
(ROD), August 1995, which MDE received on August 29, 1995. Based on the review of the Draft/Final ROD, MDE
believes the Site can be remediated in an expeditious and cost effective manner if the remediation plan
outlined in the Draft/Final ROD is implemented. Conseguently, MDE supports the SPA decision to
sign the ROD. The State will make every effort to fund its proportionate cost share for this remedial
action, providing the cost associated with implementing the remedy does not significantly escalate
during the Remedial Design (RD) Phase.

We look forward to cooperatively implementing the RD and subsequent Remedial Action at this site. If
you have any guestions

TDD FOR THE DEAF (410)K 631-3009 "Together We Can Clean Up"

-------
Mr. Thomas Voltaggio, Director

regarding this matter, please contact me at  (410) 631-3304, or have
your staff contact Mr. Robert A. DeMarco, Administrator of the
Environmental Restoration and Redevelopment Program at  (410) 631-3437.

                               Sincerely,

                               

                               Richard W. Collins, Director
                               Waste Management Administration
RWC:sg

cc:  Mr. Stephanie Dehnhard, U.S. EPA
     Mr. Peter Ludzia, U.S. EPA
     Mr. Robert A. DeMarco
     Ms. Hilary Miller
     Ms. Michele Mosco-Lascuola

-------