EPA/ROD/R04-98/020
                                    1998
EPA Superfund
     Record of Decision:
     MILAN ARMY AMMUNITION PLANT
     EPA ID: TN0210020582
     OU 10,11,12,15
     MILAN, TN
     03/11/1998

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EPA 541-R98-020



4WD-FFB

Lieutenant Colonel Billy J. Dowdy
Commanding Officer
ATTN: SMCMI-IO  (200-la)
Milan Army Ammunition Plant
Milan,Tennessee 38358-5000

SUBJ:  No Action Record of Decision
        Milan Army Ammunition Plant,  T-N,  NPL Site

Dear Lt. Col. Dowdy:

The U.S. Environmental Protection Agency  (EPA) has reviewed the No Action Record of Decision
pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980,
as amended by the Superfund Amendments and Re-authorization Act of 1986.  EPA concurs with the
finding and selected remedy presented in the No Action Record of Decision for the Salvage Yard,
Former Ammunition Burnout Area and Landfill Operable Units  (OU).

If you have any guestions regarding this action, please contact me at  (404)562-8651 or my staff.
Pete Dao, at  (404) 562-8508.

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                                         Milan Army Ammunition Plant
                                          Operable Units  10,  11,  12
                                           No Action ROD, Jan 1998
Background:

       Operable Unit 10 is a 15 acres Former Burnout Area that was in operation from 1945 until
the 1950s.  Disassembly and burnout of ordnance items occurred within concrete pad areas at this
OU.  Currently, it is being used as a pistol firing range.

       Operable Unit 11 is 41 acres landfill currently permitted under the State of Tennessee
Solid Waste Regulation.  It has been in use since the 1960s.  Rubbish from industrial operation,
consisting of paper, shipping containers, cardboard boxes, and filter pads, were placed in
trenches and covered with soil.

       Operable Unit 12 is a 4.6 acres Salvage Yard with an unknown date for original start of
usage.  It is currently still in use for the storage of salvageable scrap metal including
casing, machinery and wood.

Remedial Investigation and Risk Assessment Results:

       Operable unit 10 detected metals in soil and sediment above background and RBC screening
levels for arsenic, barium thallium, beryllium, chromium, iron, vanadium and manganese.
Groundwater constituent exceeded RBC for beryllium, cadmium, chromium, bis-2 ethylhexyl
phthalate and 1, 3,5-trinitrobenzene.

       A risk assessment was performed for these constituents. A 4.2 x 10 -5 risk and 0.71 HI
were calculated for potable ground water use. Risk associated with soil exposure resulted in a
2 x 10 -5 and a 1.9 HI.  Thallium contributed most to the HI but it has an uncertainty factor of
3000.

       OU 11 groundwater exceeded RBC for bis-2-ethylhexyl phthalate,  1, 3,5-trinitrobenzene,
RDX, 2,4,6-TNT, chloroform, beryllium, and cadmium. No soil exceeded background or RBC.

       A 1.2 x 10 -4 risk and 0.23 HI for groundwater were obtained, with beryllium contributing
9.6 x 10 -5 to the total.  Highest level for beryllium was 1.54 Ig/L.  The MCL is 4 Ig/L.  The
soil does not pose any risk.

       OU 12 groundwater did not exceed any background or RBC.  Soil exceeded background and RBC
for thallium, beryllium, copper, cadmium, chromium, iron, lead, and zinc.

       The cumulative risk of 1.1 x 10 -5 and a 13 HI was calculated with 4.2 HQ for copper,  2 HQ
for Iron and 4 HQ for Thallium.  There is a high uncertainty associated with copper because the
RfD was back calculated from MCLG for copper in drinking water.  Iron and thallium have a 1,000
and 3,000 uncertainty factor applied to the toxicity value.

None of the OUs pose a threat to ecological receptor.

Recommended Remedy:

       No Action is recommended for all three OUs base on the low potential for unacceptable
risk.

Public Participation and State Acceptance:

       A public availability session was held on December 4, 1997 with the public comment period
from November 27, 1997 through December 26, 1997.  No comments were received.

The State of Tennessee concurred with the proposed plan on December 18, 1997.

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                                           MLAAP Record of Decision

                                              Table of Contents
Section                                                                                Page

       Declaration 	   vi

1.0    Site Name,  Location,  and Description 	  1-1

2 . 0    Site History and Enforcement Activities 	  2-1

3. 0    Highlights  of Community Participation 	  3-1

4.0    Scope and Role of Response Action 	  4-1

5.0    Summary of  Site Characteristics 	  5-1
       5 .1    Geology 	  5-1
              5.1.1 Soil 	  5-2
              5.1.2 Groundwater 	  5-2
       5.2    Characteristics  of Contamination 	  5-2
              5.2.1 Salvage  Yard 	  5-3
              5.2.2 Former ABA 	  5-8
              5.2.3 Sanitary Landfill  	  5-16

6.0    Human Health and Ecological Evaluation 	  6-1
       6.1    Obj ectives and Scope of  the  Health Evaluation 	  6-1
       6.2    Data Evaluation  	  6-1
              6.2.1 Salvage  Yard 	  6-1
              6.2.2 Former Ammunition  Burnout Area 	  6-2
              6.2.3 Sanitary Landfill  	  6-2
       6.3    Exposure Pathway Analysis  	  6-2
              6.3.1 Human Exposure Pathways 	  6-3
              6.3.2 Ecological Exposure  Pathways 	  6-3
       6. 4    Health-Based Screening Evaluation  	  6-4
              6.4.1 Risk-Based Concentration Screen 	  6-4
              6.4.2 Nutritional Essentially 	  6-7
              6.4.3 Background Comparison  	  6-7
       6.5    Site-Specific  Risk-Based Screening Results  	  6-8
              6.5.1 Salvage  Yard 	  6-8
              6.5.2 Former Ammunition  Burnout Area 	  6-13
              6.5.3 Sanitary Landfill  	  6-18
       6.6    Cumulative Risk  Characterization 	  6-21
              6.6.1 Methods  for Calculating Carcinogenic  Risks  	  6-21
              6.6.2 Methods  for Calculating Noncarcinogenic Risks  	  6-25
              6.6.3 Site-Specific Cumulative Risk Results 	  6-26
      6.7     Summary of Risk  Screen and Cumulative Risk  Results  	  6-35
              6.7.1 Groundwater 	  6-37
              6.7.2 Soil 	  6-37

7. 0    Basis for NFA Recommendation 	  7-1

References 	  REF-1


                                                List of Tables

Table 5-1     Range and Maximum Constituent Concentrations Reported for  Groundwater
              Data for the Salvage Yard  	  5-5
Table 5-2     Range and Maximum Constituent Concentrations Reported for  Subsurface Soils
              Data Reported  for the Salvage Yard 	  5-7

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                                           MLAAP Record of Decision
                                        Table of Contents  (continued)

Table 5-3     Range and Maximum Constituent Concentrations  Reported for  Surface  Soils
              Data Reported for the  Salvage Yard 	  5-9
Table 5-4     Groundwater Results  for  the  Former ABA	  5-11
Table 5-5     Surface  Soils Data Reported  for  the Former AEA	  5-15
Table 5-6     Subsurface Soils  Data  Reported for the Former ABA	  5-17
Table 5-7     Groundwater Results  for  Monitor  Wells  Located Near the Sanitary  Landfill  ...  5-19
Table 5-8     Surface  Soil Data Reported for the Sanitary  Landfill  	  5-25
Table 5-9     Subsurface Soil Data Reported for  the  Sanitary Landfill 	  5-27
Table 6-1     Summary  of EPA Region  IV Risk-Based Concentrations Used for  Screening	  6-5
Table 6-2     Summary  of Screening Values  Based  on Provisional  Toxicity  Information  	  6-6
Table 6-3     Comparison of Residual Groundwater Contamination  at the Salvage  Yard to
              MCLs,  Risk-Based  Concentrations, and Background 	  6-9
Table 6-4     Comparison of Residual Surface Soil Contamination at  the Salvage Yard
              to RBCs  and Background Concentrations  	  6-11
Table 6-5     Comparison of Residual Subsurface  Soil Contamination  at the  Salvage Yard
              to RBCs  and Background Concentrations  	  6-12
Table 6-6     Comparison of Residual Groundwater Contamination  at Former ABA to  MCLs,
              RBCs,  and Background Concentrations 	  6-14
Table 6-7   Comparison of Residual Surface Soil  Contamination at the Former ABA to
              RBCs and Background  Concentrations 	  6-15
Table 6-8     Comparison of Residual Subsurface  Soil Contamination  at the  Former ABA to
              RBCs and Background  Concentrations 	  6-17
Table 6-9     Comparison of Residual Groundwater Contamination  at the Sanitary Landfill
              to MCLs,  RBCs, and Background Concentrations  	  6-19
Table 6-10    Comparison of Residual Surface Soil Contamination at  the Sanitary  Landfill
              to RBCs  and Background Concentrations  	  6-20
Table 6-11    Comparison of Residual Subsurface  Soil Contamination  at the  Sanitary
              Landfill to RBCs  and Background  Concentrations 	  6-22
Table 6-12    Summary  of Risks  and His for Chemicals Detected in Surface Soil  at the
              Salvage  Yard Exceeding RBCs  Based  on Residential  Exposure  	  6-27
Table 6-13    Summary  of Risks  and His for Chemicals Detected in Surface Soil  at the
              Former ABA Exceeding RBCs Based  on Residential Exposure 	  6-28
Table 6-14    Summary  of Risks  and His for Chemicals Detected in Surface Soil  Exceeding
              RBCs Based on Industrial Exposure  	  6-30
Table 6-15    Summary  of Risks  and His for Chemicals Detected in Subsurface Soil
              Exceeding RBCs Based on  Construction Exposure 	  6-31
Table 6-16    Summary  of Risks  and His for Chemicals Detected in Groundwater Below
              MCLs but Exceeding RBCs  or Background  Concentrations  	  6-32
Table 6-17    Justification of  No  Further  Action for All Media  at the Study Areas 	  6-36


                                                List of  Figures

Figure 1-1    Location of MLAAP in Western Tennessee 	  1-2
Figure 1-2    Location of Salvage  Yard,  Former Ammunition  Burnout Area,  and
              Sanitary Landfill at MLAAP 	  1-3
Figure 5-1    Monitor  Well Location  at the Salvage Yard, MLAAP  	  5-4
Figure 5-2    Salvage  Yard Boring  Locations, MLAAP 	  5-6
Figure 5-3    Monitor  Well Locations at the Former Ammunition Burnout Area,  MLAAP 	  5-10
Figure 5-4    Former Ammunition Burnout Area Boring  Location, MLAAP 	  5-14
Figure 5-5    Monitor  Well Location  at the Sanitary  Landfill, MLAAP 	  5-18
Figure 5-6    Sanitary Landfill Boring Locations,  MLAAP  	  5-24
Figure 5-7    Ditch 8  Location  at  the  Sanitary Landfill, MLAAP  	  5-28

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Appendix A
Appendix B
                           Table of Contents  (continued)

                                List of Appendices

Responsiveness Summary
Health-Based Screening Equations and Toxicity Assessment
                                      List of Acronyms and Abbreviations

ABA           Ammunition Burnout Area
BDL           below detection limit
BW            body weight
CERCLA        Comprehensive Environmental Response,  Compensation,  and Liability Act of 1980
COG           chemical of concern
COPC          chemical of potential concern
CR            contact rate
CSF           cancer slope factor
DA            U.S.  Department of the Army
DoD           U.S.  Department of Defense
13DNB         1,3-dinitrobenzene
24DNT         2,4-dinitrotoluene
2A46DNT       2-amino-4,  6-dinitrotoluene
4A26DNT       4-amino-2,  6-dinitrotoluene
EC            effects concentration
EF            exposure frequency
EPA           U.S.  Environmental Protection Agency
EPA           U.S.  Environmental Protection Agency
ERM           Environmental Resources Management,  Inc.
ESE           Environmental Science & Engineering,  Inc.
FDI           Fluor Daniel, Inc.
ft            foot
GAG           granular activated carbon
HI            hazard index
HMX           cyclotetramethylene tetranitramine
HQ            hazard quotient
HRA           health risk assessment
ICF           ICF Kaiser Engineers, Inc.
IRDMIS        Installation Restoration Data Management Information System
LMOS          Lockheed Martin Ordnance Systems,  Inc.
MCL           maximum contaminant level
MCLG          maximum contaminant level goal
MEV           million electron volt
mg/kg         milligram per kilogram
MLAAP         Milan Army Ammunition Plant
mm            millimeter
MMOS          Martin Marietta Ordnance Systems,  Inc.
MOC           Milan Ordnance Center
MOD           Milan Ordnance Depot
NCP           National Contingency Plan
NFA           No Further Action
OBG           Open Burning Ground
PWTF          Pink Water Treatment Facility
RBC           risk-based concentration
RDX           hexahydro-1,3,5-trinitro-l,3,5-triazine
RfD           reference dose
RI            Remedial Investigation
ROD           Record of Decision
SARA          Superfund Amendments and Reauthorization Act of 1986

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                                        Table  of Contents  (continued)

TAL           target analyte list
TDEC          Tennessee Department of Environment  and Conservation
135TND        1,  3,5-trinitrobenzene
246TNT        2, 4, 6-trinitrotoluene
TR            target risk
Ig/g          micrograms per grain
Ig/L          micrograms per liter
USAGE         U.S.Army Corps of Engineers
USAEC         U.S.Army Environmental Center
VOC           volatile organic compound
WCOP          Wolf Creek Ordnance Plant

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                                           MLAAP Record of Decision

                                    Declaration for the Record of Decision
Site Name and Location
This Record of Decision  (ROD) addresses the following three sites at Milan Army Ammunition
Plant  (MLAAP), Gibson and Carroll Counties, Tennessee:

       •      Salvage Yard,
       •      Former Ammunition Burnout Area,  and
       •      Sanitary Landfill.

Statement of Basis and Purpose
This decision document presents the selected action for the Salvage Yard, Former Ammunition
Burnout Area  (ABA),  and Sanitary Landfill at MLAAP, located in Gibson and Carroll Counties,
TN. No Further Action  (NFA)  was 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) to the extent practicable. Selection of NFA
also considered the National Contingency Plan, to the extent practicable, and is based on
information in the Administrative Record for MLAAP.

The U.S. Environmental Protection Agency (EPA) and the State of Tennessee concur on the selected
remedy.

Description of the Selected Remedy
This ROD addresses the final response action planned for the Salvage Yard, Former ABA, and
Sanitary Landfill, including soil and groundwater.  No previous RODs or decision documents have
been issued for these sites.  A Human Health Evaluation identified no unacceptable risks to
human health at these three sites.  Furthermore, terrestrial ecological exposure was considered
insignificant.  Therefore, remedial action is not necessary.

NFA is the selected remedy for soil and groundwater at the Salvage Yard, Former ABA, and
Sanitary Landfill.  The selected remedy manages the risk to acceptable levels for both human
health and the environment and is the final action planned.   The selected remedy will ensure
risks to human health and the environment are within acceptable limits.

Declaration Statement
Based on the soil and groundwater investigation results at the Salvage Yard, Former ABA, and
Sanitary Landfill, it was determined that no remedial action is necessary to ensure protection
of human health and the environment.

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                                           MLAAP Record of Decision

1.0    Site Name, Location, and Description

The Milan Army Ammunition Plant  (MLAAP) is located in Gibson and Carroll Counties, in west-
central Tennessee, approximately 50 miles east of the Mississippi River  (see Fig. 1-1).   The
City of Milan, with a population of 8,100, borders the installation to the northwest.  Other
nearby population centers include Humboldt, with a population of 10,200, which lies 12 miles to
the southwest; Trenton, with a population of 4,600, which lies 15 miles to the northwest; and
Jackson, with a population of 50,000, lies 18 miles south of MLAAP RCF Kaiser Engineers, Inc.
(ICF),  19911.  MLAAP is served by two rail lines, three U.S. highways, and four state highways.
Interstate 40 passes within 13 miles south of the installation.

The three areas at MLAAP addressed in this Record of Decision  (ROD) are:

            The Salvage Yard,
       •    The Former Ammunition Burnout Area (ABA) (sometimes referred to as "Sunny-Slope"), and
            The Sanitary Landfill.

The Salvage Yard at MLAAP is located east of Area J, immediately south of U.S. Highway 104
(Fig.  1-2) in Carroll County, Tennessee.  The Salvage Yard occupies about 4.6 acres.  All
salvageable, non-hazardous scrap, including casings, machinery, and wood generated at MLAAP is
stored either in bins or in outdoor piles until sold to a scrap dealer.

The Former ABA at MLAAP is located in Area V of the southwestern portion of the installation
(Fig.  1-2) in Gibson County, Tennessee, and occupies approximately 15 acres.  The area consists
of various concrete aprons and barricaded buildings, an earth-covered storage igloo, and an
office building.  The area is currently used as a pistol firing range.  Surface drainage from
the area flows into the West Fork of Wolf Creek  [Fluor Daniel, Inc.  (FDI), 1996].

The Sanitary Landfill at MLAAP is located north-northwest of Area W  (Fig. 1-2) in Carroll
County, Tennessee, and occupies about 41 acres.  Debris from industrial operations consisting
mainly of such items as paper, shipping containers, cardboard boxes, and filter pads are placed
in trenches, compacted, and covered with soil  (ICF, 1991).  The Sanitary Landfill is currently
permitted under the State of Tennessee Solid Waste regulations.

Access to all three sites is controlled by MLAAP, via onsite security and/or fences and gates.

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2.0    Site History and Enforcement Activities

The date the Salvage Yard was first used is not known.  In the past, scrap metal was stored
outdoors, directly on the ground surface. It was later determined that lead from the scrap piles
had leached into the soil (ICF, 1991).   Subseguently, lead-containing materials have been stored
under a roof.

The Former ABA was built in the spring of 1945 and designated for the disassembly and burning of
munitions.  Operations consisted of the following sequential unit activities:  receiving, base
plate removal, defusing, and burring and band removal of individual munitions.  Industrial
activities in this area are believed to have ceased during the 1950s.  No disposal or burial of
munitions is thought to have occurred in this area (FBI, 1996).   Unit activities were conducted
within concrete pad areas and consisted of disassembly and burnout of ordnance items.

The Sanitary Landfill is thought to have been in use since 1960.  Historic aerial imagery
indicates cleared areas starting in 1960 with various trenches for waste disposal appearing in
later years.  Rubbish and debris from industrial operations  (consisting mainly of paper,
shipping containers, cardboard boxes, and filter pads) are placed in trenches, compacted, and
covered with soil at the Sanitary Landfill.  The trenches are excavated down to a clay material,
which may retard leachate migration  (FBI, 1996).

MLAAP was constructed between 1940 and 1942 and initially included approximately 28,521 acres.
The H.K. Ferguson Engineering Company of Cleveland, Ohio, and the Oman Construction Company of
Nashville, Tennessee, formed The Ferguson-Oman Company to design and construct the plant.
Various production lines encompassed approximately 550 acres; storage facilities covered
approximately 7,380 acres; field services encompassed approximately 9,900 acres; and
administrative, shop maintenance, housing, recreation and other functions covered approximately
1,395 acres.  The remaining acreage was necessary to comply with regulations regarding safety
clearances between explosive manufacturing areas.

Portions of the original acreage have been leased, sold, or deeded to various organizations over
the years, including "Line G," which was sold to the United States Rubber Company, acreage that
was deeded to the City of Milan and the University of Tennessee, and acreage that was leased or
transferred to the Tennessee National Guard.  As a result of these and other minor transactions,
MLAAP currently (1996)  covers about 22,436 acres.

MLAAP has experienced changes to its mission, name, and contract operators throughout the years.
A chronology of operational events at MLAAP is summarized as follows:

       1942    MLAAP originally  consisted of  two  facilities:  the Wolf  Creek  Ordnance  Plant
                (WCOP)   and  the Milan Ordnance  Depot  (MOD).   WCOP was  operated by  the Proctor  and
               Gamble  Defense  Corporation,  and MOD wasoperated  by the Government.

       1943    WCOP  and MOD were merged  into  a single  facility, the Milan Ordnance Center  (MOC).
               MOC was  operated by  the Proctor and Gamble Defense Corporation.  The mission of
               the  facility included: the production of fuzes,  boosters, and  completed rounds of
               small and  large caliber munitions;  the  operation of  an ammonium  nitrate plant; and
               the  shipment of munitions.   Employment  peaked at 11,000  from  1943  to  1945.

       1945    MOC was  designated as the Milan Arsenal  and was  placed on standby  status  under
               U.S.  Department of the Army (DA)  operation at the conclusion  of  World War II.  The
               mission of the  facility was  changed to  the receipt,  storage,  and processing of
               ammunition returning from overseas; normal maintenance,  surveillance, renovation,
               and  demilitarization; and limited  new production.

       1953    Milan Arsenal was returned to  active  status to support the Korean  Conflict;
               Proctor and  Gamble Defense Corporation  assumed operations.  The  mission of the
               facility included increased output of new munitions,  inclusion of  experimental
               munitions, and  assignment of engineering studies for  ordnance  munitions loading
               plants.  Employment  reached 8,000  from 1953 to 1954.
       1954    Milan Arsenal was designated as a  "permanent  installation."   Production cutbacks

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         resulted in  the  layaway  of various  load  lines during  1954  and  1955, until  all
         production ceased in  1957, leaving  only  a  small demilitarization program at Line
         B.

1957     Milan Arsenal was placed on  inactive  status. Proctor  and Gamble Defense
         Corporation  terminated their contract with the Government,  and Harvey Aluminum
         Sales,  Inc.  became  operating contractor.

1960     The  industrial areas  at  Milan Arsenal were returned to  active  status.
         Modernization of these facilities has occurred throughout  the  1960s to produce:
         fuzes,  primers,  delay plungers, delay elements, and boosters;  40,  60, 81,  90, 105,
         106, and 155 millimeter  (mm)  munitions;  mine, grenade,  and cluster bomb unit
         dispensers;  demolition kits;  shell  metal parts; pelleting  explosives; and  rework
         and  renovation of munitions  items.

1961   The industrial portion  of  Milan Arsenal is designated as  Milan Ordnance  Plant;  the
       field services portion  is  designated  as Milan Depot Activity.

1962   Field services activities  were discontinued at Milan Depot Activity, and  operations
       were merged with Milan  Ordnance Plant.   The field  services Mission  continued under
       Milan Ordnance Depot.

1963   Milan Ordnance Depot  was designated as  Milan Army Ammunition Plant.

1969   Harvey Aluminum Sales,  Inc. was acguired  by Martin  Marietta, Inc. Martin  Marietta,
       Inc. became the operating  contractor.

1971   Production Lines E,  F,  and H were placed  in layaway.   The production of munitions
       and components on  these lines  was transferred to other  lines on the  facility;
       eguipment used to  manufacture  metal parts  was transferred to private industry.

1975   Production Line Z  was canceled. The line  was placed in  layaway status  in  1976 with
       production of  items  transferred to  other  lines at  the plant.  Line  C production was
       transferred to Line  B in 1977  and then  was placed  in layaway status.

1977   Line H was reactivated  to  produce LAP M739 fuzes, because it contained the
       humidity/temperature-controlled led environment necessary to produce fuzes.

1978   Modernization  of MLAAP  was initiated  and  continued  through  1985. Production Lines
       A, C,  and Z were modernized.   Automated production  of 60- and 81-mm propellant
       increments was completed under this program in addition to  the development  of a
       melting  system.  Testing/production of  these systems was  completed  in 1983  and  then
       ceased for production layaway  in  1984.   Limited production  of 60- and 81-mm mortar
       rounds was transferred  to  Line D.

       An X-ray facility  was constructed at  Line  V to perform all nondestructive testing of
       munitions at the MLAAP. The X-ray  facility [which  contains  an underground  4-million
       electron volt  (MEV)  unit,  a 0.420-MEV unit,  and a  fluoroscope with video  tape]  is
       the world's largest  facility dedicated  to  nondestructive  testing of  munitions.

1979   Construction of Pink  Water Treatment  Facilities  (PWTFs) was  initiated and completed
       in 1981.  These plants  are used to  remove  explosive contaminants from process water,
       using filtration and  granular  activated carbon (GAG)  adsorption, prior to water
       discharge into ditches.

1985   Martin Marietta, Inc. organized Martin  Marietta Ordnance  Systems, Inc.  (MMOS),  as a
       subsidiary of  Martin  Marietta, Inc.,  to operate MLAAP.

1995   MMOS merged with Lockheed  to form Lockheed Martin,  Inc.  and  was  renamed  to  Lockheed
       Martin Ordnance Systems, Inc.   (LMOS).

1997   General  Dynamics became the installation  operating  contractor.

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3. 0    Highlights of Community Participation

A Remedial Investigation  (RI) was conducted by ICF in 1990 to investigate the extent of
contamination at the Salvage Yard, Former ABA, and Sanitary Landfill, as well as other areas at
MLAAP.  The findings were documented in the Remedial Investigation for Milan Army
Ammunition Plant (ICF, 1991).

FBI conducted RI work in 1995 and collected supplemental information at the Former ABA and
Sanitary Landfill  (as well as other sites in the Southern Area); their findings were documented
in the Milan Army Ammunition Plant, Remedial Investigation, Southern Study Area  (Operable Unit
No. 5)  (17131, 1996).

The 1991 RI report  (ICF, 1991) was released to the public in December 1991. The 1996 RI
report  (FBI, 1996)  was released to the public in April 1996.  Both documents were made available
to the public in the Administrative Record and at the Information Repositories, maintained at
the Army Industrial Operations Office at MLAAP and the Mildred G. Fields Library in Milan,
Tennessee.  In November 1997, the Proposed Plan for the Salvage Yard, Former ABA, and Sanitary
Landfill  [Environmental Science & Engineering, Inc. (ESE), 1996] was released to the public.

A public availability meeting announcement for the Proposed Plan was published in the Milan
Mirror & Exchange and Jackson Sun.  A Public Availability Meeting for the Proposed Plan was held
at the Tom C. McCutchen Agricultural Museum on December 4, 1997.  At this meeting,
representatives from MLAAP, the U.S. Army Corps of Engineers (USAGE), the U.S. Environmental
Protection Agency  (EPA) Region IV, and the Tennessee Department of Environment and Conservation
(TDEC) were available to answer guestions about the site and the NFA decision under
consideration.

A public comment period for the recommended actions at the Salvage Yard, Former ABA, and
Sanitary Landfill was held from November 27 through December 26, 1997.  Comments received during
this period, as well as those received at the public meeting, are addressed in the
Responsiveness Summary included in Appendix A.

This document presents the basis for the No Further Action decision at the Salvage Yard, Former
ABA, and Sanitary Landfill at MLAAP.  This decision was recommended in accordance with
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as
amended by the Superfund Amendments and Reauthorization Acts (SARA) of 1986, to the extent
practicable, the National Contingency Plan (NCP),  and the Tennessee Health and Safety Code.
This decision for this site was based on the Administrative Record.

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4.0    Scope and Role of Response Action

The scope of the response action for the Salvage Yard, Former ABA, and Sanitary Landfill
addresses soil and groundwater.  This ROD addresses the final response action planned for the
Salvage Yard, Former ABA, and Sanitary Landfill.  No previous ROD(s) or decision document(s)
have been issued for these sites.

Two other RODs have been finalized in OU3 and OU4:

       •    One for the industrial area soils (these soils located at the manufacturing lines at
            the installation),  and
       •    One for groundwater  (specificafly, groundwater in the northern boundary area that is
            migrating offsite).

Other sites currently under investigation in OU3 and OU4 are:

       •    The non-industrial area soils (primarily soils and sediments in ditches within OU3),
            and
       •    Onsite groundwater.

The onsite groundwater operable unit addresses all groundwater within the installation
boundaries, with the exception of those areas addressed by other groundwater operable units,
specifically OU1 (0-Line Ponds),  the portion of OU3 addressed by the northern boundary
groundwater ROD (previously referenced above), and OU4 Region I  (X-Line).

No other RODs have been finalized for OU5.  OU5  (also referred to as the Southern Study Area)
covers the largest land area at MLAA.P.  Aside from the Former ABA and the Sanitary Landfill,
which are discussed in this plan, major areas investigated in OU5 include the:

       •    Open Burning Ground,
       •    Former Ammunition Destruction Area,
       •    Current Ammunition Destruction Area,
       •    Ammunition Storage Area, and
       •    Ammunition Test Area.

Those sites within OU3, OU4, and OU5 that are currently under investigation will be discussed
with the public in the future.

Several human exposure scenario's were evaluated for the Salvage Yard, Former ABA, and Sanitary
Landfill:

       •    Industrial worker scenario,
       •    Construction worker scenario, and
       •    Residential user scenario.

The future residential use scenario is hypothetical and assumes that the Salvage Yard, Former
ABA, and Sanitary Landfill can be used for unrestricted land use.  An unrestricted land use
would permit groundwater wells and residential areas to be constructed anywhere on these three
sites.  The future residential land use scenario, which was evaluated for comparative purposes,
is the most conservative choice for land use and will generate the greatest potential exposure.
However, it is unlikely that MLAA.P' s missions will be eliminated and the plant's land would be
used for residential purposes.

Since MLAA.P currently fulfills a critical mission that will be necessary as part of future Army
operations, and it is Army practice to clean up to the current land use scenario, no clean up
decisions were based on the future residential use scenario.  If, in the future, MLAAP would be
subject to base closure, site-related risk would be re-evaluated in accordance with, U.S.
Department of Defense  (DoD) base closure policy  (10 U.S.C. 2687 and NOTE).

A CERCLA investigation conducted at these sites concluded that the three sites pose no
unacceptable risks to either human health or the environment.  During the course of this

-------
investigation, MLAAP recommended that these three sites be considered NFA sites  (ICF, 1991; FBI,
1996).
A no-action determination is appropriate when:
       •    The site, or a specific problem or area of the site, poses no current or potential
            threat to human health or the environment; or
       •    CERCLA does not provide the authority to take a remedial action; or
       •    A previous response eliminated the need for further remedial response.

The Salvage Yard and Sanitary Landfill are recommended for NFA because they do not pose a
current or potential threat to human health and the environment.

Although the Former ABA is still used as a pistol firing range and the previous mission at this
location has ceased, CERCLA has regulatory authority.  The Former ABA is recommended for NFA
because this site does not pose a current or potential threat to human health or the
environment.

EPA and TDEC have reviewed the 1991 RI (ICF, 1991) and 1996 RI  (FBI, 1996) and agree that NFA is
an appropriate remedial response action for the Salvage Yard, Former ABA, and Sanitary Landfill.

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5.0    Summary of Site Characteristics

5.1    Geology

The 1996 RI report  (FBI, 1996) contained a detailed description of the site geology.  This
description is briefly summarized as follows.

Western Tennessee  (including MLAAP)  lies on the eastern flank of the Upper Mississippi River
Embayment.  Structurally, the embayment is a downwarped, downfaulted trough whose axis
approximates the current course of the Mississippi River. Sediments, ranging in age from
Cretaceous to Recent, have been deposited in this trough.  These sediments consist of gravel,
sand, clay, lignite, chalk, and limestone units of varying thicknesses.

MLAAP is situated on the Memphis Sand  (or "500-foot" sand) of the Claiborne Group of Tertiary
age in the Gulf Costal Plain of western Tennessee.  The Memphis Sand crops out in a broad belt
across western Tennessee, but is covered in most places by fluvial deposits of Tertiary and
Quaternary age and loess and alluvium of Quaternary age.  The eastern boundary of the Memphis
Sand and the contact between the Wilcox and Claiborne Groups in the subsurface have been mapped
by various researchers.  The western boundary of the outcrop belt is not well established
because the contact between the Memphis Sand and the overlying Cook Mountain Formation is
covered by fluvial deposits, loess,  or alluvium.

The Memphis Sand consists of a thick body of sand that includes subordinate lenses or beds of
clay and silt at various horizons.  The clay and silt locally are carbonaceous and lignitic;
thin lenses of lignite also occur locally.  Thick beds of clay and silt in the upper part of the
Memphis Sand may, in some places, be confused with the overlying Cook Mountain Formation.

Sand in the Memphis Sand ranges from very fine to very coarse, but is commonly fine, fine to
medium, or medium to coarse.  The Memphis Sand ranges to 900 feet (ft) thick.  The formation is
thinnest along the eastern limits of the outcrop belt in Hardeman, Madison, Carroll, and Henry
Counties.  In western Tennessee, the base of the Memphis Sand dips westward at rates of 20 to 50
ft per mile.

The Claiborne Group is underlain by the Wilcox Group, which consists of the Flour Island
Formation, the Fort Pillow Sand  (or "1,400-foot" sand), and the Old Breastwork's Formation
(listed in increasing depth).   The Flour Island Formation consists primarily of clay, silt,
sand, and lignite and is not an aguifer.  Where present, it serves as the lower confining unit
for the Memphis Sand and the upper confining unit of the Fort Pillow Sand.  The Flour Island
Formation is approximately 50 ft thick in the vicinity of MLAAP.

A geologic cross section through MLAAP identifies the stratigraphic units underneath this area.
Underlying the Wilcox is the Porters Creek Clay, which acts as a confining unit between the Fort
Pillow Sand of the Wilcox Group and the McNairy Sand of Cretaceous age.  The exact depth to rock
under MLAAP is unknown.  A test well drilled to 1,289 ft about 20 miles south-southwest of MLAAP
near Jackson, Tennessee, was stopped in a sandy clay marl.  It was estimated that rock (possibly
limestone) would be encountered between 500 to 800 ft below the drilled depth of the test well
(FBI, 1996).

5.1.1  Soil

The surface soils at MLAAP consist chiefly of a reddish-brown to yellow, mottled, silty clay
that grades into a clay unit with depth.  The soil types include the Memphis, Loring, Grenada,
Galloway, Henry, Falaya, and Waverly soil associations. Based on topography, the Memphis and
Loring series occur on higher elevations and are well-drained soils.  The Henry soil series is
somewhat poorly drained and is usually associated with flat terrain, while the Falaya and
Waverly soils associations occur in the low areas and are poorly drained.

Drill logs from borings installed at the site indicate that the upper 12 to 15 ft of soil
consists of reddish-brown to tan silty lean clay with some layers of sandy and fat clay.   Below
these depths, sands with varying amounts of silts and clays, have been encountered.  Occasional
gravel, up to 3/8-inch diameter, has been encountered during boring operations.  A more sandy

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alluvium of lesser thickness (5 to 10 ft) has been observed in several areas across the site.
Natural and artificial drainage systems have incised into the alluvium in several locations.

5.1.2  Groundwater

Groundwater in the MLAA.P area generally flows northwest, in the direction of regional dip of
these sands, and also trends northerly because of the topographic influence.  On a general
scale, there are no abrupt hydrologic boundaries in the aguifer.  The formation is recognized as
sand with clay lenses and clay rich zones, which may locally alter vertical groundwater flow,
and stratification of the sediments tends to make vertical conductivities lower than horizontal
conductivities.

5.2    Characteristics of Contamination

This section summarizes the findings of characterization studies conducted for soil and
groundwater at the Salvage Yard, Former ABA, and Sanitary Landfill.

5.2.1  Salvage Yard

5.2.1.1  Groundwater

Monitor well MI035, located downgradient from the Salvage Yard, has been sampled five times
between 1983 and 1997.  The location of MI035 with respect to the Salvage Yard is depicted in
Fig. 5-1.  Target analytes in sampling efforts have included metals, volatile organic compounds
(VOCs), and explosives, although not all analytes were targeted in each of the five sampling
episodes.

No VOCs or explosives were detected in any of the samples collected from MI035 between 1983 and
1997.  Thirteen metals were detected.  Table 5-1 presents the analytical results for groundwater
at the Salvage Yard as well as relevant background information, regulatory criteria, and
sampling dates.   With the exception of cadmium and mercury in 1983, all metals were less than
maximum contaminant levels (MCLs)  and/or two-times the site-specific background concentration
[Environmental Resources Management, Inc. (ERM), 1995].  Based on EPA Guidance (EPA, 1995), site
constituents present at concentrations less than two-times the site- specific background
concentration do not need further evaluation (see Sec. 6.0).

The elevated levels of cadmium and mercury at MI035 were reported for samples collected in 1983.
Since that time, MI035 was sampled four more times.  Cadmium was targeted for all four sampling
efforts, and mercury was targeted twice and most recently.  Cadmium was detected at a
concentration of 3.68 micrograms per liter  (Ig/L) in September 1988; it was not detected in
sampling events  conducted in January 1989, October 1990, and April 1997.  Mercury was not
detected in either of the two sampling events (October 1990 and April 1997) where it was a
targeted analyte.  Based on this information, the 1983 data is not considered representative.
Results of these analyses show cadmium and mercury to be present at concentrations less than
MCLs and less than two-times the site-specific background concentrations established for the
site.

5.2.1.2  Soil

ICF collected subsurface soil samples at the Salvage Yard and reported findings in the 1991 RI
Report  (ICF, 1991).  Two soil borings were installed to address potential contamination (Fig.
5-2):  Boring SYD-1 was placed downgradient from the lead bin; and Boring SYD-2 was placed
downgradient from the metal scrap pile. Because a railroad track is located upgradient of the
lead bin, an upgradient boring was not installed. Samples were collected at a depth of 5 to 7
feet.

Twelve metals and four organic chemicals were detected in soil samples collected from the
Salvage Yard.  Table 5-2 summarizes these data and provides relevant background soil
information.  Aluminum, arsenic, barium, calcium, lead, manganese, magnesium, silver, and
vanadium were detected at concentrations greater than two-times the site-specific background
concentrations  (FBI, 1996).  All other metals were reported at concentrations less than
two-times the site-specific background concentrations or were not detected.  Based on EPA

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                       Table  5-1. Range  and Maximum Constituent  Concentrations  Reported
                                   for Groundwater Data at the Salvage Yard
Chemical
               MCL6
MI035              (Ig/L)
(63ft)       Exceeded? (Yes/No)
             2x Background
Backgroundl          (Ig/L)
(Ig/L)       Exceeded? (Yes/No)
Inorganic
Aluminum
Barium
Calcium
Cadmium
Chromium
Copper
Iron
Lead
Mercury
Potassium
Magnesium
Manganese
Sodium
Compounds :
ND-137
43-45.1
6,560-6,740
ND-41 3(3.68)
ND-13
ND-12.9
ND-312
ND-1.41
ND-3.3 4
1,980-2,470
1,540-2,340
5.91-7.55
3, 660-3,760
                                         200 5/No
                                         2,000/No
                                            — I —
                                             5/No 8
                                           100/No
                                        2,000/No
                                        300 5/Yes
                                           157/No
                                            2/No 9
                                           — I —
                                           — I —
                                         50 5/No
                                           — I —
                                             27,750
                                               81.5
                                             19,100
                                                 ND
                                               21.3
                                             35.7
                                             18,450
                                                 ND
                                                 ND
                                            2,240
                                            6,855
                                              231.5
                                           33,050
                           55,500/No
                              163/No
                           38,200/No
                               ND/Yes
                             42.6/No
                             71.4/No
                           36,900/No
                               ND/Yes
                               ND/Yes
                            4,480/No
                           13,710/No
                              463/No
                           66,100/No
                         Dates Sampled 2: 3/83, 9/88, 1/89, 10/90, 4/97

Note:  -- = not determined.
        ND = not detected.

1  Based  on  data  from MI229,  as presented in  ERM,  1995.
2  Not  all metals were  targeted in  all  events.
3  Value  reported for 3/83.  Subseguent  samples  collected  in  9/88,  1/89,  10/90,  and  4/97  show cadium less
   than the  MCL  (maximum of  3.68  Ig/L);  3/93  data  are not considered  representative.
4  Value  reported for 3/83.  Subseguent  samples, collected in 10/90 and 4/97,  show mercury  less  than the MCL
   and  non-detect,  3/83 data are  not  considered representative.
5  40 CFR Part  143,  Secondary MCL.
6  40 CFR Part  141,  MCL.
7  40 CFR Part  141,  action level  in no  more than 10  percent  of  the tap samples.
8  When 3/83 data is disregarded, see Note 3.
9  When 3/83 data is disregarded, see Note 4.

Source:   QST.

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Table 5-2.   Range and Maximum Constituent Concentrations Reported for
                 Subsurface Soils at the Salvage Yard

Chemical
Inorganic Compounds :
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Cadmium
Cobalt
Chromium
Copper
Iron
Lead
Manganese
Magnesium
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
Organic Compounds :
Acetone
2-Propanol
Trhichl or oclurome thane
Toluene
SYD-1
5-7ft 1

10350
ND
4.64
132
ND
854
ND
ND
ND
ND
11000
18
984
1920
ND
ND
423
ND
0.313 (2)
414
ND
34.5
ND

0.046 (2)
NR
0.064
0.12
SYD-2
5-7ft

11000
ND
3.51
139
ND
659
ND
ND
ND
ND
9900
7.94
761
1840
ND
ND
492
ND
ND
392
ND
32.8
ND

0.061
0.24
<0.0059
<0.0078
Background
(mg/kg)

5390
ND
1.73
22.1
ND
234
ND
1.36
9.27
4.33
5730
2.42
50.3
370
ND
3.86
251
0.26
ND
364
ND
16.1
9.67

—
—
—
—
2x Background
(mg/kg)

10780
ND
3.46
44.2
ND
468
ND
2.72
18.54
8.66
11460
4.84
100.6
740
ND
7.72
502
0.52
ND
728
ND
32.21
19.34

—
—
—
—
2x Background
Exceeded?

Yes
No
Yes
Yes
No
Yes
No
No
No
No
No
Yes
Yes
Yes
No
No
No
No
Yes
No
No
Yes
No

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Guidance  (EPA, 1995), site constituents present at concentrations less than two-times the
site-specific background concentration do not need further evaluation  (see Sec. 6.0).  Sec. 6.0
discusses the significance of the metals detected in excess of the site specific average
background concentration and organic constituents (acetone, 2-propanol, trichlorofluromethane,
and toluene) reported in Table 5-2.

The 1991 RI report concluded that contaminant loading from the Salvage Yard into groundwater
was not occurring  (ICF, 1991).

In 1997, QST collected two surficial soil samples (0 to 1 ft) from approximately the sample
locations as the borings collected for the RI effort conducted in 1990; metals and explosives
were targeted for these two samples.  This data is summarized in Table 5-3.  RDX was detected in
one sample  (SYD-2) at a concentration of 0.172 milligrams per kilogram (mg/kg).  Except for
beryllium, cadmium, chromium, copper, iron, lead, mercury, nickel, silver, sodium, thallium, and
zinc, all other metals were reported at levels less than two-times the site-specific background
concentration or were not detected, and thus do not need further evaluation (see Sec. 6.0).
Sec. 6.0 discusses the significance of the metals detected in excess of the site specific
average background concentration and RDX reported in Table 5-3.

5.2.2  Former ABA

5.2.2.1  Groundwater

Six monitor wells were installed in the Former ABA (Fig. 5-3).   Table 5-4 summarizes analytical
data collected at each well, as well as relevant background information,  regulatory criteria,
and sampling dates.  Each monitor well at the Former ABA was sampled at least once, but was not
always analyzed for all of the constituents listed in Table 5-4.

Twenty metals and six organic compounds were detected in groundwater between 1990 and 1995.
Five explosive-related compounds (135TNB, 13DNB, HMX, nitrobenzene, and RDX) were detected at
low concentrations. Bis-2-ethylhexyl phthalate was also detected once at a concentration of 5.7
Ig/L.  Sec. 6.0 discusses the environmental significance of the organics reported in the Former
ABA.

Of the 20 metals detected at wells in the Fortner ABA, 14 have either primary or secondary MCLs,
and all have established site-specific background concentrations.  Seven primary or secondary
MCLs were exceeded over the course of all sampling events; 16 occurrences of a metal exceeding
two-times the average site-specific average background concentrations were documented.  Seven
metals exceeded both MCLs and levels two-times the average site-specific average background
concentrations.

The maximum concentration of cadmium as listed in Table 5-3 was 23.2 Ig/L for MI073.  This
sample was collected in November 1990. Subsequent samples collected in May 1994 [below detection
limit (BDL)], October 1994  (BDL),  and February 1995  (2.17 Ig/L) detected cadmium concentrations
below MCLs.  Given the subsequent data for cadmium at MI073, it would not be appropriate to
consider the high concentration reported in 1990 as representative.

With respect to metals, MI233 generally contained the highest concentrations,  as listed in Table
5-3.  This well was only sampled once, therefore, no subsequent data have been collected to
confirm the elevated metals reported at MI233.  Because MI227  (the shallow well clustered with
MI233)  does not show similar or higher levels of contamination, this indicates that the source
of the elevated metals at MI233 is not the Former ABA.  MI233 is screened in a fine sand zone of
the aquifer, and thus elevated metals may be due to solids related to soil material in samples
and are not representative of groundwater.

Sec. 6.5.2 presents more information on the environmental significance of data reported in Table
5-3.

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                     Table  5-3.  Range and Maximum Constituent Concentrations Reported for
                                        Surface Soils  at the Salvage Yard


Chemical
Inorganic Compounds :
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Cadmium
Cobalt
Chromium
Copper
Iron
Lead
Manganese
Magnesium
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
SYD-1
(0-1 ft)
(mg/kg)

3750
ND
3.27
65
ND
2370
20.9
4.25
8.56
13000
8110
195
462
419
ND
7.16
368
ND
1.2
230
ND
12.6
340
SYD-2 1
(0-1 ft)
(mg/kg)

4490
ND
5.97
186
1.62
5500
29.5
6.04
75.2
462
45200
639
494
139
0.343
34.8
334
ND
2.35
459
39.1
16.4
2495

Background
(mg/kg)

12478.33
2.21
5.03
99.37
0.49
4317
1.23
6.93
16.17
21.36
14833.33
15
638
1459.5
0.11
13.06
695.7
0.29
ND
225.5
ND
27.38
63.03

2x Background
(mg/kg)

24956.66
4.42
10.06
198.74
0.98
8634
2.46
13.86
32.34
42-72
29666.66
30
1276
2919
0.22
26.12
1391.4
0.58
ND
451
ND
54.76
126.06

2x Background
Exceeded?

No
No
No
No
Yes
No
Yes
No
Yes
Yes
Yes
Yes
No
No
Yes
Yes
No
No
Yes
Yes
Yes
No
Yes
Organic Compounds:
RDX
                         <0.163
                                       0.172
                                                            ND
                                                                              ND
                                                                                              No
Note:  ND = not detected.

1  Average concentration of original and duplicate  samples.

Source: QST.

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Table 5-4.   Groundwater Results for the Former ABA



Chemical
Inorganic
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Cadmium
Cobalt
Copper
Iron
Mercury
Potassium
Magnesium
Manganese
Sodium
Nickel
Lead
Selenium
Silver
Thallium
Vanadium

MI073
(94 ft) 4
(Ig/L)
Compounds :
54 .4-1, 350
ND
1.25
12.7-22.3
0.51
1, 600-2, 990
2.17-23.2 3
3. 36
3 16
2.16-14 .3
49.5-974
ND-1 .12
ND-1,510
497-555
10.7-39.7
6,050-9,180
4.86
1.15-5.42
ND
ND
ND
ND

MI226
(35 R) 4
(Ig/L)

868-1,140
ND
ND
108-120
0 . 63
3,080-3, 610
3.14
4 .67
ND 15 4
4 .33
876-1,530
0.232
1,220-1, 620
1,510-1,700
34.8-40.9
4, 650-4, 900
13.5
1 .63-2.25
0.95
ND
ND
5.6

MI227
(32 ft) 4
(Ig/L)

550-1,070
ND
ND
120-123
0.65
3,160-3, 990
2.54
5.11
ND 36 1
4 .72
471-1,300
ND
681-1,330
1,700-1,800
63.8-87 .3
4,880-5, 950
33.2
ND-4 .23
1.9
ND
ND
5.83

MI228
(130 ft) 4
(Ig/L)

1,560-5,570
ND
ND-3.09
49.3-75.9
0.58
1,890-4,800
2.54
4 .28
8 88 9 31
6.1-13.1
1, 480-1, 590
ND
1,130-5, 660
939-1,360
58.2-154
5,040-13, 900
9.68
2.8-3.58
ND
ND
ND
7.53-20.8

MI232
(80 ft) 4
(Ig/L)

1,470-9,500
ND
1.1
34 .5-91.8
0.61
3,740-6,800
1.69
4 .75
8 33 ^6 1
3.94-22.8
1,210-12,700
ND
1,280-2,410
1,490-2,370
27.7-219
5,040-5,830
8.48
2 .5-16.6
ND
ND
ND
8 .06-55.8

MI 2 33
(90 ft) 4
(Ig/L)

67, 600
ND
16. 6
362
7.63
28,500
ND
ND
116
73.5
39, 600
2.23
5,880
10,900
1,200
58,700
ND
180
ND
ND
ND
275
MCL 6
(Ig/L)/
Exceeded?
Yes /No

200/Yes
6/No
50/No
2,000/N<
4 /Yes
	 / 	
5/No 3
	 / 	
1 007 Yes
1, 300/No
300/Yes
2/Yes
	 / 	
	 / 	
50/Yes
__/ —
100/No
15/Yes
50/No
50/No
2
— /__
                                    27,750
                                      ND
                                     6.08
                                     81.5
                                      ND
                                    19,100
                                      ND
                                      ND
                                     21.3
                                     35.7
                                    18,450
                                      ND
                                     2,240
                                     6,855
                                     231.5
                                    33,050
                                      ND
                                     12.85
                                      ND
                                      ND
                                      ND
                                     50.1
55,500/Yes
   No/No
 12.15/Yes
  163/Yes
   ND/Yes
 38,200/No
   ND/Yes
   ND/Yes
  42.6/Yes
  71.4/Yes
 36,900/Yes
   ND/Yes
 4,480/Yes
 13,710/No
  463/Yes
 66,100/No
   ND/Yes
  25.7/Yes
   ND/Yes
    No/No
    No/No
  100.2/Yes

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                                                                               Table 5-4.  Groundwater  Results for  the Former ABA




Chemical
Zinc


MI073
(94 ft) 4
(Ig/L)
10.2-44.7


MI226
(35 R) 4
(Ig/L)
13.8


MI227
(32 ft) 4
(Ig/L)
ND-22


MI228
(130 ft) 4
(Ig/L)
17.8-67.2


MI232
(80 ft) 4
(Ig/L)
14.8-45

MCL 6
MI233 (Ig/L)/
(90 ft) 4 Exceeded? Background 7
(Ig/L) Yes/No (Ig/L)
138 5,000/No 1 81.75
2x
Background
(Ig/L)/
Exceeded?
(Yes/No)
163.5/No
Organic Compounds :
135TNB
13DNB
bis-2-ethylhexyl
phthalate
HMX
Nitrobenzene
RDX
Sample Dates 5



ND-0.107
ND
5.7

ND
ND
ND
11/90
5/94
10/94
2/95
0.223
ND
NA

ND-1. 69
0.596
ND
5/94
2/95


0.188-0.285
0.634-0.893
NA

ND
ND
ND
5/94
2/95


0.137-0.153
ND
NA

ND
ND
0.395-0.422
5/94
2/95


ND
ND
ND

ND
ND
ND
5/94
2/95


0.475 --/-_
ND — / —
NA 6/No

ND — / —
0.489 --/-_
ND — / —
5/94



— / —
__/__
--/--

--/--
— / —
__/__




1   Secondary MCL,  40 CFR Part  143.
2   40 CFR Part 141,  action levels in no  more  than  10  percent  of  the  tap  samples.
3   High of 23.2 ppb  cadmium reported in  Nov/90.  Subsequent  samples collected  in May/94  (ND), Oct/94  (ND), and Feb/95  (2.17 Ig/L)report cadmium less than MCL; therefore,  site data do
    not suppport the  use of the 23.2  ppb  cadmium  concentration for screening.
4   FDI, 1996.
5   Not all analytes  were targeted on referenced  dates.
6   40 CFR Part 141,  MCLs.
7   Background from MI229,  as presented in ERM, 1995.

-------
5.2.2.2  Soil

ICF collected fifteen soil samples and one sediment sample at the Former ABA and reported
findings in the 1991 RI report  (ICF, 1991).  Five soil borings  (CBG-1 to CBG-5) were completed
to investigate potential soil contamination resulting from past burn activities  (Fig. 5-4).  All
soil boring sites were drilled to 12 ft; three samples per boring were collected.  One sediment
sample  (CREK-1) was collected from the west fork of Wolf Creek where the ditch from the burnout
pad drains into the creek.  Soil and sediment samples were analyzed for inorganic and organic
chemicals.

A total of five surface soil samples (0-2 ft) and one sediment sample (0-1 ft) were collected at
shallow depths.  Fifteen metals and five organic compounds were detected in surface soil and
sediment samples collected from the Former ABA.  This information is presented in Table 5-5,
along with relevant site-specific background information.  Four of the samples were only
analyzed for cadmium, chromium, lead, and mercury.  The other two samples were analyzed for the
TAL metals.  Sample CREK-1 generally contained the highest levels of constituents at the Former
ABA.  With the exception of arsenic, barium, calcium, cobalt, chromium,  iron, lead, manganese,
magnesium, silver, and vanadium, all other metals were reported at concentrations less than
two-times the average site- specific background concentration or were not detected.  Based on
EPA Guidance (EPA, 1995), site constituents present at concentrations less than two-times the
site-specific background concentration do not need further evaluation.  Organic compounds
detected in soil samples from the Former ABA were present at low concentrations.

A total of 10 deep soil samples (five at 5 to 7 ft, and five at 10 to 12 ft) were collected at
the Former ABA.  Six of the ten samples were only analyzed for cadmium,  chromium, lead, and
mercury.  The remaining samples were analyzed for TAL metals.  Fourteen metals and five organic
compounds were detected in soil samples collected from the Former ABA; these data are summarized
in Table 5-6, along with relevant site-specific background information.  With the exception of
aluminum, arsenic, barium, calcium, chromium, iron, lead, manganese, magnesium, potassium,
silver, and zinc, all metals were present at concentrations less than two-times the
site-specific background concentrations established for the Southern Study Area  (FBI, 1996) or
were not detected.  Based on EPA Guidance (EPA, 1995), site constituents present at
concentrations less than two-times the site-specific background concentration do not need
further evaluation.  Organic compounds detected in soil samples from the Former ABA were present
at low concentrations.

Sec. 6.0 discusses the significance of the other metals detected in excess of site specific
background concentrations and the organic constituents reported in Table 5-6.

The 1991 RI report (ICF, 1991)  concluded that there is no evidence that the Former ABA is
contributing to groundwater contamination.

5.2.3  Sanitary Landfill

5.2.3.1  Groundwater

Data from 11 monitor wells, located downgradient and side gradient to the Sanitary Landfill,
were evaluated with respect to groundwater guality (Fig. 5-5). Twenty-four organic compounds and
21 metals were detected in these monitor wells during 13 sampling episodes conducted between
1982 and 1994.  Table 5-7 summarizes these data, as well as site-specific average background data
for groundwater, regulatory criteria, and sample dates.

Organic compounds were generally detected infreguently and at low concentrations.  Although
explosive-related compounds (135TNB, 246TNT, 24DNT, 2A46DNT, 4A26DNT, nitrobenzene, tetryl, HMX,
and RDX) were detected, the source of these constituents is not believed to be the Sanitary
Landfill.

-------
Table 5-5. Surface Soils Data Reported for the Former ABA


Chemical
Inorganic Compounds :
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Cadmium
Cobalt
Chromium
Copper
Iron
Lead
Manganese
Magnesium
Mercury
Nickel
Potassium
Selenium
Silver 0
Sodium
Thallium
Vanadium
Zinc
Organic Compounds :
Acetone
1, 2-Epoxy-
cyclohexene
2-Cyclohexen-
l-ol
2-Cyclohexen-
1-one
Trichloro- <0
flourome thane
Palmatic Acid
CBG-1
(0-2 ft)
(mg/kg)

6500
<3.8
3.58
169
<1.86
15000
<3.05
<15
<12.7
<58.6
7800
15.4
1230
1280
<0.05
<12.6
334
<0.25
.0758
348
<31.3
80
58.9

0.025
0.34

0.22

0.11

.0059

0.22
CBG-2 CBG-3 CBG-4 CBG-5 CREK-1
(0-2 ft) (0-2 ft) (0-2 ft) (0-2 ft) (0-1 ft)
(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg)

4600
<3.8
15
1200
<1.86
637
<3.05 <3.05 <3.05 <3.05 <3.05
54.2
<12.7 <12.7 <12.7 <12.7 42
<58.6
32000
30.2 80.2 58 13.3 17
6690
519
<0.05 <0.05 <0.05 <0.05 <0.05
<12.6
178
<0.25
<0.025
346
<31.3
59.1
<30.2

<0.017
0.22

0.22

0.11

<0.0059

NR

Background 1
(mg/kg)

12478.33
2.21
5.03
99.37
0.49
4317
1.23
6.93
16.17
21.36
14833.33
15
638
1459.5
0.11
13.06
695.7
0.29
ND
225.5
ND
27.38
63.03

—
--

—

--

—

—
2x
Background
(mg/kg) /
Exceeded?
(Yes/No)

24956. 66/No
4.42/No
10.06/Yes
198.74/Yes
0.98 /No
8634/Yes
2.46/No
13.86/Yes
32.34/Yes
42.72/No
29666. 66/Yes
30/Yes
1276/Yes
2919/No
0.22/No
26.12/No
1391. 4/No
0.58/No
0/Yes
451/No
0/No
54.76/Yes
126.06/No

— / —
— / —

— I —

— / —

— / —

— / —
                    QST.

-------

                                                           Table  5-6.  Surface Soils Data Reported for  the Former ABA
                              CBG-l         CBG-1       CBG-2         CBG-2        CBG-3        CBG-3         CBG-4          CBG-4         CBG-5       CBG-5
                     5-7 ft       10-12 ft     5-7 ft      10-12 ft       5-7 ft      10-12 ft       5-7 ft        10-12 ft        5-7 ft     10-12 ft       Background
                     (mg/kg)
                                  (mg/kg)
                                              (mg/kg)
Inorganic  Compounds:
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Cadmium
Cobalt
Chromium              <1
Copper
Iron                  —
Lead                   6
Manganese              —
Magnesium              —
Mercury               <0
Nickel
Potassium              —
Selenium              —
Silver
Sodium                —
Thallium
Vanadium              —
Zinc                  —
Organic Compounds:
Acetone               —
1,2-Epoxycyclohexene   —
2-Cyclohexen-l-ol
2-Cyclohexen-l-one     —
Trichloroflouromethane —
2-Propanol            —

Note:
                                                           (mg/kg)
                                                                        (mg/kg)
                                                                                    (mg/kg)
                                                                                                 (mg/kg)
                                                                                                                 (mg/kg)
                                                                                                                               (mg/kg)
                                                                                                                                           (mg/kg)
                                                                                                                                                          (mg/kg)
                                                                                                                                                                        2x Background (mg/kg)/
                                                                                                                                                                          Exceeded? (Yes/No)
10780/Yes
     0/No
 3.46/Yes
 44.2/Yes
     0/No
  468/Yes
     0/No
  2.72/No
18.54/Yes
  8.66/No
11460/Yes
 4.84/Yes
100.6/Yes
  740/Yes
     0/No
  7.72/No
  502/Yes
  0.52/No
    0/Yes
   728/No
     0/No
  32.2/No
19.34/Yes

-------
                                                                  Table 5.7.   Groundwater  Results for Monitor Wells Located Near the  Sanitary Landfill
                                                                                                                  (Page  1 of 3)
Chemical
(Depth) 3
 MI279        MI280        003       MI264        MI265        004        MI266
(151 ft)     (295  ft)      (222 ft)    (125 ft)      (295 ft)    (164 ft)    (115 ft)
 (Ig/L)       (Ig/L)        (Ig/L)     (Ig/L)        (Ig/L)      (Ig/L)      (Ig/L)
 MI267        MI062        MI063
(295 ft)    (100 ft)      (160 ft)
  (Ig/L)       (Ig/L)       (Ig/L)
               MCL
 MI064       (Ig/L)/
(247 ft)     Exceeded?
   (Ig/L)       (Yes/No)
                                                                                                                                                                   Background
                                                                                                                                                                       (Ig/L)
                                                                                                                                                                                         2x
                                                                                                                                                                                   Background
                                                                                                                                                                                     (Ig/L)/
                                                                                                                                                                                    Exceeded?
                                                                                                                                                                                      (Yes/No)
Inorganic Compounds:
Silver
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Nickel
Lead
                            2.52-3.37
                               5820
                                ND
                               1.4
                             21.4-23
                            0.94-0.97
                              2,250-
                              2,270
                            1.91-2.78
                            5.16-5.23
                            9.92-10.4
                            8.34-9.67
                              2,740-
                              3,000
                               ND
                              1,080-
                              1,310
                              1,170-
                              1,260
                            72.3-73.5
                              3,600-
                              3,630
                            7. 66-9.32
                            5.75-6.25
ND
1520
ND
1.3
15.3-20
ND
1,770-
2,520
ND-4. 08
ND
ND-11.9
ND
386-2, 170
ND
1160
ND
ND
8.61-23.4
ND
2,310-
10,500
ND-5.33
ND
ND-9. 16
ND-13.7
ND-1,490
ND
336
ND
ND
11.3-15.8
ND
2,500-
31, 000
ND-70. 9
ND
ND
3.44-35.3
87. 1-182
                                                                                                        ND
                                                                                                        10

-------
                                                                  Table 5.7.   Groundwater  Results for Monitor Wells  Located Near the Sanitary Landfill
                                                                                                                  (Page 2 of 3)
Chemical
(Depth) 3
 MI279        MI280        003       MI264       MI265        004        MI266
(151 ft)     (295  ft)     (222 ft)    (125 ft)      (295 ft)    (164 ft)    (115 ft)
 (Ig/L)       (Ig/L)        (Ig/L)     (Ig/L)        (Ig/L)      (Ig/L)      (Ig/L)
                                 MI267        MI062       MI063
                                (295  ft)     (100 ft)      (160 ft)
                                   (Ig/L)      (Ig/L)       (Ig/L)
                                                                      MCL
                                                         MI064       (Ig/L)/
                                                        (247 ft)      Exceeded?
                                                           (Ig/L)      (Yes/No)
                                                            Background
                                                                (Ig/L)
     2x
Background
  (Ig/L)/
 Exceeded?
    (Yes/No)
Organic  Compounds:
135TNB
24DNT

2-Amino-4 , 6-
dinitrotoluene
2-Propanol
4-Amino-2 , 6-
dinitroluene
Acetone
Bis(2-ethylhexyl)
phthalate
Benzo[b]fluoranthene
Chloroform
N,N-Diethyl-3-
methy1benzamide
Di-n-octyl phthalate
Di-N-butyl phthalate
Dioctyl  adipate
               NA
               ND
               NA
               NA
               NA
ND

ND

ND

ND

NA
ND
                                                  ND
                                                  ND
                                                  NA
NA
11
ND

ND

ND

ND

NA
ND
                                   ND
                                   ND
                                   NA
                                                                       ND
                                                                       10

                                                                       ND
                                                                       ND
                                                                       4

-------
                                                                Table  5.7.   Groundwater  Results  for Monitor Wells  Located Near the Sanitary  Landfill
                                                                                                              (Page 3  of 3)

Chemical
(Depth) 3
Ethylbenzene
HMX
Laurie Acid
Toluene
2 -ButaNone/ methyl
ethyl ketone
Nitrobenzene
Phenol
RDX

Tetryl

Xylenes , total combined
Dates Sampled 4






MI279
(151 ft)
(Ig/L)
NA
31
NA
NA
NA

ND
NA
310

4.02

NA
2/95






MI280
(295 ft)
(Ig/L)
NA
ND
NA
NA
NA

ND
NA
ND

ND

NA
2/95






003
(222 ft)
(Ig/L)
ND
ND-17. 8
NA
7
13

ND
1
9.4-430

ND-
0. 999
2
10 times
between
4/82-
2/86,
11/90,
3/92,
10/94
MI264
(125 ft)
(Ig/L)
ND
ND
NA
5-6
9

ND
ND
0.472-
0.605
ND

1-2
10/94






MI265
(295 ft)
(Ig/L)
ND
ND
NA
4
9

ND
ND
ND

ND

1
10/94






  004       MI266
(164 ft)    (115 ft)
  (Ig/L)      (Ig/L)
 MI267       MI062
(295 ft)     (100 ft)
  (Ig/L)      (Ig/L)
                                                                                                       ND
                                                                                                        1
                                                                                                       ND
                                                                                                                                                    MCL
                                                                                                                             MI063      MI064       (Ig/L)/
                                                                                                                            (160 ft)     (247 ft)     Exceeded?
                                                                                                                              (Ig/L)      (Ig/L)      (Yes/No)
Background
    (Ig/L)
    2x
Background
  (Ig/L)/
 Exceeded?
    (Yes/No)
1  Secondary MCL, 40 CFR,  Part 143.
2  40 CFR Part  141,action  levels in  no more than  10 percent of the top samples.
3  FDI, 1996.
4  All constituents may not have been targeted on all referenced sample dates.

-------
The Sanitary Landfill is located directly above the groundwater plume emanating from the Open
Burning Ground  (OBG).  Monitor wells located downgradient of the Sanitary Landfill in the
shallow regional aguifer (MI062, MI264, and MI266) all indicated contamination by nitrobodies.
Levels of nitrobodies in shallow downgradient monitor wells of the Sanitary Landfill are
approximately 1 to 2 orders of magnitude less in concentration than those located within the OBG
suggesting that nitrobodies detected are associated with the OBG plume of the Sanitary Landfill
is a minor source of groundwater contamination.  Groundwater contamination orginating from the
OBG extended beneath the Sanitary Landfill to Route 54, and tends to migrate downward beneath
the Sanitary Landfill into the middle protion of the aguifer possibly due to recharge from Ditch
8 located between the Sanitary Landfill and OBG during precipitation events (FBI, 1996).

Elevated levels of bis-2-ethylheyl phthalate have also been detected in monitor wells
downgradient from the landfill.  However, similar to explosive related compounds,
bis-2-ethylhexyl phthalate has also been detected upgradient of the landfill,  indicating that
the OBG is a likely source of contamination.

Contaminant levels in shallow monitor wells downgradient of the Sanitary Landfill may be
associated with the upper portion of the OBG plume located within the shallow portion of the
regional aguifer (FBI, 1996).   The southern portion of the OBG plume does not exhibit this
downward migration.  Sec. 6.0 discusses the environmental significance of the organic
constituents detected in groundwater near the Sanitary Landfill.  The OBG plume will be
addressed as part of the site-wide groundwater operable unit and the southern studies area
operable unit.

The MCLs for cadmium and mercury were exceeded at Wells 003 and 004.  The regulatory guidance
level of lead was also exceeded in Well 003.  The cadmium exceedance at Well 003 of 194 Ig/L was
reported in November 1990.  Since that time, two additional samples have been collected from Well
003; a March 1992 sample detected cadmium at 8 Ig/L, and an October 1994 sample reported cadmium
as less than detection limits.  The one previous sample collected at Well 003 (March 1983) also
reported a lower level of cadmium (8 Ig/L).  Based on this information, it appears that the
November 1990 cadmium concentration is an anomaly and could be due to solids related to soil
material in the groundwater sample and thus is not considered representative of groundwater.

The cadmium exceedance of 9 Ig/L at Well 004 was reported in 1983.  Two samples have been
collected from this wells since that time, March 1992  (less than 0.1 Ig/L)  and October 1994
(4.36 Ig/L), show cadmium present at levels less than the MCL of 5 Ig/L.

The maximum cadmium concentration reported at MI063 is 5.33 Ig/L.  However, another sample
pulled on this date was reported at less than 4.01 Ig/L.  MI063 was sampled two more times.

These results showed cadmium to be less than a detection limit of 7.9 Ig/L in December 1992 and
less than a detection limit of 4.01 Ig/L in August 1993.

The cadmium exceedance of 70.9 Ig/L at MI064 was reported in 1990.  Since that time, three
groundwater samples have been collected  (December 1992, August 1993, and October 1994).   The
analytical results showed cadmium to be present at levels below detection limits.

The mercury exceedances at Wells 003 and 004 both occurred in 1983.  Since that time, each well
has been sampled once for mercury (November 1990).  Mercury was not detected in either sample.

The regulatory guidance level exceedance of lead at Well 003 was reported in 1990. Since that
time, two groundwater samples have been analyzed for lead (March 1992 and October 1994).
Both samples showed lead levels less than the regulatory guidance level of 15 Ig/L.

Cadmium was reported above the MCL of 5 Ig/L in Wells 003 and 004 at various times.  Recent
samples collected form these wells have shown cadmium levels have decreased.  However, it is
unlikely that the Sanitary Landfill is a source of the historical groundwater contamination at
Wells 003 and 004.   The 1991 RI report concluded that although contaminants were detected in
Wells 003 and 004,  given the relative depths of these wells, the small distances between the
Sanitary Landfill and the wells, and because soil contamination was not observed, it is unlikely
that the Sanitary Landfill is a source of groundwater contamination at these wells  (ICF,  1991).
In addition to this conclusion, the shallower wells do not exhibit eguivalent or higher levels

-------
of contamination, as would be expected if the Sanitary Landfill was a source of groundwater
contamination.  Other wells considered too deep to monitor contamination from the Sanitary
Landfill are MI064, MI267, and MI289.

Sec. 6.0 discusses the environmental significance of the data reported in Table 5-7.

5.2.3.2  Soil

ICF collected soil samples at the Sanitary Landfill and reported findings in the 1991 RI report
(ICF, 1991).   Two soil borings were completed to investigate soil contamination resulting from
disposal activities currently conducted at MLAAP.  Both borings  (LF-1 and LF-2) were installed
downgradient of the Sanitary Landfill  (Fig. 5-6) and drilled to 12 ft.  All soil samples were
collected and analyzed for selected inorganic and organic chemicals.

Two soil samples were collected near the surface (LF-1 at 0-1 ft and LF-2 at 0-7 ft).  These
samples were only analyzed for cadmium, chromium, lead, and mercury.  Lead was the only targeted
metal reported.  Data reported in Table 5-8 shows these four metals to be present at low
concentrations and less than two times the average site specific background concentration.
Based on EPA Guidance (EPA, 1995), site constituents present at concentrations less than
two-times the site-specific background concentration do not need further evaluation.

A total of four deeper soil samples were also collected, as identified in Table 5-9 (note the
data for LF-2 0 to 7 ft is the same as that presented in Table 5-8). Twelve metals and one
organic compound  (2-propanol)  were reported in deep soil samples collected from the Sanitary
Landfill area; these data are summarized in Table 5-9, along with site-specific average
background data.  Except for aluminum, arsenic, barium, calcium, iron, lead, manganese,
magnesium, potassium, silver,  and vanadium, all other metals were less than two-times the
site-specific background concentrations established for the Southern Study Area (FBI, 1996) or
not detected.  Based on EPA Guidance  (EPA, 1995), site constituents present at concentrations
less than two-times the site-specific background concentration do not need further evaluation.
Sec. 6.0 discusses the significance of metals as well as 2-propanol reported in the deeper soil
samples near the sanitary landfill.

One surface water  (08SW01) and one sediment (08SE01) sample were also collected from the
Sanitary Landfill area,  in Ditch 8 (Fig. 5-7), as part of the 1995 RI effort. Ditch 8 receives
surface runoff from various areas  (the eastern portion of Area "L", and areas south of Line C),
including the OBG.  Nitrobodies were not detected in the sediment, and heavy metal
concentrations were within two-times the established site background levels.  Nitrobodies were
not detected in surface water with the exception of RDX (0.267 Ig/L).  The OBG is the likely
source of RDX.  Heavy metals were detected at levels below regulatory criteria and standards.
Surface water samples located downstream indicate levels of HMX and RDX appear to be due to
runoff from the OBG  (FDI, 1996).

Because Ditch 8 receives runoff from several different areas, it would not be appropriate to
represent surface water and sediment data from this location as being attributed to the Sanitary
Landfill.  For this reason, these data are not presented in this ROD.  Ditch 8 will be addressed
in a separate ROD  (Operable Unit No.  5).

Based on the above discussion, it appears that waste disposal activities at the Sanitary
Landfill are not impacting groundwater guality  (FDI, 1996).

6.0    Human Health and Ecological Evaluation

6.1    Objectives and Scope of the Health Evaluation

The objective of this Human Health and Ecological Evaluation is to determine the relative
significance of the concentrations of site-related chemicals detected in soil and groundwater at
the Salvage Yard, Former ABA,  and Sanitary Landfill at MLAAP.  The relative significance of site
contamination is evaluated by comparing measured site concentrations to medium-specific

-------

                       Table 5-9.  Surface Soil Data Reported for the Sanitary Landfill
       Chemical
       (depth)

       Inorganic Compounds:
       Aluminum
       Antimony
       Arsenic
       Barium
       Beryllium
       Calcium
       Cadmium
       Cobalt
       Chromium
       Copper
       Iron
       Lead
       Magnesium
       Manganese
       Mercury
       Nickel
       Potassium
       Selenium
       Silver
       Sodium
       Thallium
       Vanadium
       Zinc
  LF-  1
(0-1 ft)
 (mg/kg)
   LF-2
(0-7 ft)  1
  (mg/kg)
          2x Background
                       (mg/kg)/
Background 2          Exceeded?
  (mg/kg)              (Yes/No)
 <3.05

 <12.7


   17


 <0.05
  <3.05

  <12.7


   14.2


  <0.05
  12,478.33
     2.21
     5.03
    99.37
     0.49
    4,317
     1.23
     6.93
    16.17
    21.36
  14,833.33
     15
   1,459.5
     638
     0.11
    13.06
   695.7
     0.29
     ND
    225.5
     ND
    27.38
    63.03
 24,956.66/No
   4.42/No
  10.06/No
 198.74/No
   0.98/No
  8,634/No
   2.46/No
  13.86/No
  32.34/No
  42.72/No
 29,666.66/No
     30/No
  2,919/No
  1,276/No
   0.22/No
  26.12/No
1,391.4/No
   0.58/No
      0/No
    451/No
      0/No
  54.76/No
 126.06/No
1 Average concentration of original and duplicate samples.
2 FD1, 1996.

-------
                                      Table 5-9.  Subsurface Soil Data Reported for the Sanitary Landfill


Chemical
(depth)
Inorganic Compounds :
Aluminum
Antimony
Arsenic
Barium
Beryllium
Calcium
Cadmium
Cobalt
Chromium
Copper
Iron
Lead
Manganese
Magnesium
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
Organic Compounds :
2-Propanol

LF- 1
(5-9 ft)
(mg/kg)

13500 (2)
<3.8
5.22 (2)
125 (2)
<1.86
627 (2)
<3.05
<15
<12.7
<58.6
13500 (2)
12.13
282
1415 (2)
<0.05
<12.6
557
<0.25
0.0559 (2)
299
<31.3
40.6 (2)
<30.2

0.0095

LF-1 LF-1 LF-2
(10-12 ft) (5-9 ft) (10-12 ft)
(mg/kg) (mg/kg) (mg/kg)

13100
<3-8
1.95
106
<1.86
1370
<3.05 <3.05 <3.05
<15
<12.7 <12.7 <12.7
<58.6
13000
6.94 14.2 8.58
148
1440
<0.05 <0.05 <0.05
<12.6
347
<0.25
<0.025
559
<31.3
43.7
<30.2

NR


Background 1
(mg/kg)

5390
ND
1.73
22.1
ND
234
ND
1.36
9.27
4.33
5730
2.42
50.3
370
ND
3.86
251
0.26
ND
364
ND
16.1
9.67


2x Background
(mg/kg) /
Exceeded?
(Yes/No)

10780/Yes
0/No
3.46/Yes
44.2/Yes
0/No
468/Yes
0/No
2.72/No
18.54/No
8. 66/No
11460/Yes
4.84/Yes
100.6/Yes
740/Yes
0/No
7.72/No
502/Yes
0.52/No
0/Yes
728/No
0/No
32.2/Yes
19.34/No

-------
health-based screening levels; if screening levels are exceeded within a medium, then a
cumulative risk analysis was performed.  The results of the screening and cumulative risk
evaluations will be used to determine whether No Further Action is an appropriate response
action for the study sites.

This health evaluation has been conducted according to various EPA Region IV and State of
Tennessee guidance and is presented in the following sections:

            Data Evaluation/Identification of Chemicals of Potential Concern (COPCs)(Sec. 6.2)
       •    Exposure Pathway Analysis  (Sec. 6.3)
       •    Health-Based Screening Evaluation (Sec. 6.4)
       •    Site-Specific Risk-based Screening Results (Sec. 6.5)
       •    Cumulative Risk Characterization (Sec. 6.6)
       •    Summary of Risk Screen and Cumulative Risk Results (Sec. 6.7)

6.2    Data Evaluation

COPCs are those hazardous constituents that may have been disposed of or released at a specific
site or surrounding environmental media.  Identification of COPCs is accomplished by examining
historical information available for the area as well as evaluating analytical results of the
environmental media sampled at the area.  A summary of the historical data evaluated for each
site is presented in the following sections.

6.2.1  Salvage Yard

The Salvage Yard was used for the storage of non-hazardous scrap, including casings, machinery,
and wood; the presence of trace levels of inorganic and organic chemicals is expected.  Thus,
any inorganic or organic compound that was detected at this area  (except if the detection is the
result of laboratory contamination)  was included as a COPC for further assessment in the health
evaluation.  The DA Installation Restoration Data Management Information System (IRDMIS)
database and the 1991 RI report (ICF, 1991) were the sources of data evaluated in this health
evaluation.

6.2.2  Former Ammunition Burnout Area

The Former ABA was used to demilitarize a wide range of conventional munitions; the presence of
trace levels of inorganic and organic compounds is expected.  Thus, any inorganic or organic
that was detected at this area (except if the detection is the result of laboratory
contamination)  was included as a COPC for further assessment in the health evaluation.  The DA
IRDMIS database, the 1991 RI report  (ICF, 1991), and the 1996 RI report  (FDI, 1996) were used as
sources for the health evaluation.

6.2.3  Sanitary Landfill

The Sanitary Landfill is used for the disposal of rubbish and debris from industrial operations
for such materials as paper, shipping containers, cardboard boxes, filter pads, and other
non-hazardous materials; the presence of trace levels of inorganic and organic compounds is
expected.  Thus, any inorganic or organic compound that was detected at this area  (except if the
detection is the result of laboratory contamination)  was included as a COPC for further
assessment in the health evaluation.  The DA IRDMIS database, the 1991 RI (ICF, 1991), and the
1996 RI for Operable Unit No. 5 (FDI, 1996) were used as sources for the health evaluation.

6. 3    Exposure Pathway Analysis

An exposure pathway is the route over which a chemical or physical agent migrates from a
contaminant source to a receptor(s).  The term also describes a unigue mechanism by which the
receptor may be potentially exposed to chemicals originating from the site.   For an exposure
pathway to be complete, the following four elements must be present:

       •    A source or release from a source (e.g.,  chemicals disposed of in soil);
       •    A likely environmental migration route (e.g., infiltration of chemicals from soil to
            groundwater);

-------
       •    An exposure point where receptors may come in contact with site-related chemical
             (e.g., direct exposure to site soil); and
       •    A route by which potential receptors may be exposed to a site-related chemical  (e.g.,
            ingestion, inhalation, or dermal absorption).

If any of these four elements is not present, the exposure pathway is considered incomplete and
is not expected to contribute to the total exposure from the site.

6.3.1  Human Exposure Pathways

A point of human exposure is the location where an exposed population or individual (receptor)
can come into contact with the subject contamination.  The potential point of exposure to
hazardous constituents is assumed to be directly at or within the boundary of each of the three
study areas.

The future land use of MLAAP is designated as industrial use.  However, to ensure that the
health-based screening evaluation is protective of human health, the most stringent unrestricted
land-use (residential) conditions were considered when comparing residual site concentrations to
residential health-based levels.  The risk evaluation also compares residual site concentrations
to industrial health-based levels.  These levels associated with industrial use are higher
because an industrial exposure scenario results in much lower exposure potential than the
residential exposure scenario.  Because a construction exposure scenario could occur at some
unforeseen time in the future, all three study sites were evaluated under this scenario as well,
whereby the subsurface soil concentrations are screened against the industrial health-based
level.

6.3.2  Ecological Exposure Pathways

Ecological exposure to residual site contaminants in soil is expected to be incomplete or
insignificant due to the absence of quality habitat at the ABA and Salvage yard, as well as low
levels of contamination at the Sanitary landfill (e.g., levels are near or below detection
limits).  As presented in Sec. 5.0, many constituents detected in all soil samples were
generally less than two-times the average site-specific background concentrations.

With respect to habitat, the Salvage Yard provides little to virtually no habitat for any
terrestrial receptor due to the presence of nonhazardous scrap, including casings, machinery,
and wood stored in bins or in piles (ICF, 1991).  The Former ABA also does not provide habitat
for terrestrial receptors as this area consists of various concrete aprons and barricaded
buildings,  an earth-covered igloo, and an office building.  In fact, the Former ABA is currently
used as a pistol firing range, which would be avoided by larger terrestrial receptors (ICF,
1991).  While the Sanitary Landfill could provide habitat for small mammals such as small
rodents (e.g., rabbits or mice), exposure to contaminants in the surface soil, which included
samples collected from 0 to 2 ft, is expected to be insignificant due to the fact that only one
metal, lead, was reported above detection limits at a concentration that is less than two-times
background.

In addition, due to the explosive hazard associated with the mission at NULAAP, large buffer
zones are located outside of the production and disposal areas; these large buffer areas provide
suitable habitat for terrestrial ecological receptors.  Due to the availability of such habitat
outside the smaller study areas under evaluation, low level terrestrial ecological exposure was
considered insignificant and was excluded from further evaluation in this health evaluation and
thus, no risk characterization was performed for terrestrial exposure to these study sites.

6.4    Health-Based Screening Evaluation

Once data evaluation has been completed and relevant exposure routes and pathways have been
defined, the concentrations of COPCs are then evaluated in a health-based screening.  According
to EPA Region IV guidance (EPA, 1995), the purpose of conducting a health-based screen is to
determine if any of the COPCs should be included in a comprehensive site-specific baseline risk
assessment.  The screening process included the following steps:

       •    Risk-Based Concentration Screen,
       •    Nutritional Essentiality,  and

-------
       •    Comparison to Background Concentrations.

6.4.1  Risk-Based Concentration Screen

The first step in the health-based screening is to compare the maximum detected site
concentrations to a risk-based concentration (RBC).   EPA Region IV has adopted the RBCs
developed by Region III for soil, drinking water, air, and fish tissue (EPA, 1995).  The RBCs
developed by Region III were derived based on default exposure scenarios to include residential
and industrial, and a target hazard index  (HI)  or lifetime cancer risk of 0.1 or 1 x 10 -6,
respectively.  The EPA established RBCs for soil and groundwater are presented in Table 6-1
along with the relevant toxicity values upon which they are based.  The algorithms used by EPA
to calculate the RBCs are presented in Appendix B.  Because not all chemicals detected at the
site have EPA established toxicity values upon which to derive RBCs, provisional RBCs were
developed based on toxicity information available from peer reviewed literature.  These
provisional levels were derived using EPA methods, and serve as guidance levels in the absence
of EPA established RBCs for such compounds (Table 6-2).   While using these provisional values
for screening purposes adds a level of uncertainty to the screening process, excluding these
chemicals from the process is adding even more uncertainty to the screening process, as
exclusion does not allow for a guantitative confirmation whether such chemicals contribute
significantly or not to the overall risk at a study site.

The health-based screening entails comparing the maximum detected value at the site to the RBC
and regulatory established value, if available.  For the three study areas, only soil and
groundwater data were evaluated. Only one surface water sample has been collected at the three
sites, and the relevance of this data is discussed in the Sec. 6.5.3 (Sanitary Landfill).

The RBC screening process used is as follows (EPA, 1995):

       •    The maximum relevant concentration of each chemical detected in each medium is
            compared to the appropriate RBC (Note: Some historical maximum concentrations are no
            longer considered relevant and, thus, were not used in the evaluation.)
       •    If the maximum concentration exceeds the RBC for that medium, the chemical is
            retained for further evaluation in a baseline health risk assessment  (HRA) to assess
            all exposure routes involving that medium; otherwise, the chemical is not further
            evaluated for that medium.
       •    If a chemical does not exceed its RBC in any medium, the chemical is not further
            evaluated in the HRA.

For the residential and industrial soil screening evaluation, the maximum site concentrations
detected in surface soil (e.g., 0 to 2 ft) are compared to the residential- and industrial-based
screening values, respectively.  Because the industrial scenario represents a more conservative
scenario than a construction scenario, the industrial RM are compared to the maximum chemical
concentrations detected in subsurface soil (> 2 ft)  to represent the construction scenario for
screening purposes.

6.4.2  Nutritional Essentiality

According to EPA region-wide guidance (1989)  and Region IV guidance (EPA, 1995) compounds that
are essential human nutrients need not be considered further in the guantitative risk
assessment.  According to Region IV these include calcium, chloride, iodine, magnesium,
phosphorus, potassium, and sodium.  If an inorganic compound detected in soil at the site was an
essential nutrient, it was excluded from consideration to be included in a HRA.

6.4.3  Background Comparison

EPA Region IV guidance (1995) states, For naturally occurring inorganics and radionuclides,
compare the onsite maximum detected concentration to 2 times the average site-specific
background concentration.  Eliminate the chemical as a COPC if it is less than 2 times the
background level.

Results of the health-based screening evaluation for soil and groundwater at each area are
presented in the following section.

-------
                                            Table 6-1.    Summary  of  EPA Region IV Risk-Based  Concentrations Used for  Screening
                                                                                                     Risk-Based Concentrations
Contaminant

INORGANICS
Aluminum
Antimony
Arsenic (as carcinogen)
Barium and compounds
Beryllium and compounds
Cadmium and compounds
Chromium VI and compounds
Cobalt
Copper and compounds
Iron
Lead
Manganese and compounds
Mercury (inorganic)
Nickel and compounds
Selenium
Silver and compounds
Thallium
Vanadium
Zinc
 7429905
 7440360
 7440382
 7440393
 7440417
 7440439
18540299
 7440484
 7440508
 7439896
 7439921
 7439965
 7439976
 7440020
 7782492
 7440224
 7446156
 7440622
 7440666
                                                                      RfDo
                                                                   mg/kg/d
                                    RED I
                                 mg/kg/d
1.4E-04

5.7E-05
                CPSo
             kgod/mg
                CPSI
             kgod/mg
             8.4E+00
             6.3E+00
             4.2E+01
                NA
                NA
                NA
                NA
                NA
                NA
                NA
                NA
                NA
                NA
                NA
                NA
 Tap
Water
 ug/L
                                             1.8E+00
                                             1.8E+01
       Soil Ingestion
Industrial         Residential
   mg/kg              mg/kg
                        2.0E+05 N
                        8.2E+01 N
                        3.8E+00 C
                        1.4E-04 N
                        1.3E+00 C
                        l.OE+02 N
                        l.OE+03 N
                        1.2E+04 N
                        8.2E+03 N
                        6.1E+04 N
                        l.OE+03 L
                        4.7E+03 N
                        6.1E+01 N
                        4.1E+03 N
                        l.OE+03 N
                        l.OE+03 N
                        1.6E+01 N
                        1.4E+03 N
                        6.1E+04 N
                                                                                     3.9E+01 N
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
                                      EPA
ORGANICS
Acetone                                              67641
Benzo(b)fluoranthene                                205992
Bis(2-ethylhexyl)phalate(DEHP)                       117817
Chloroform                                           67663
Dibutyl phthalate                                    84742
1,3-Dinitrobenzene                                   99650
Dinitrotoluene mixture                              ND
2,4-Dinitrotoluene                                  121142
2,6-Dinitrotoluene                                  606202
Di-n-Octyl phthalate                                117840
Di-N-octyladipate                                   123795
1,2-Epoxycylohexene                                 ND
Ethylbenzene                                        100414
Hexahydro-1,3,5-trinitro-l,3,5-triazine(RDX)         121824
Methyl ethyl ketone                                  78933
Nitrobenzene                                         98953
Octahydro-1357-tetranitro-1357-tetrazocine(HMX)     2691410
Toluene                                             108883
Trichlorofluoromethane                               75694
1,3,5-Trinitrobenzene                                99354
Trinitrophenylmethylnitramine                       479458
2,4,6-Trinitrotoluene                               118967
Xylene  (mixed)                                     1330207
                  1.OE-01
                  3.OE-03
                  6.OE-01
                  5.OE-04
                  5.OE-02
                  2.OE-01
                  3.OE-01
                  5.OE-05
                  1.OE-02
                  5.OE-04
2.9E-01
5.7E-04
   NA
7.3E-01
1.4E-02
6.1E-03
   NA
   NA
6.8E-01
   NA
   NA
   NA
   NA
   NA
   NA
1.1E-01
   NA
   NA
   NA
   NA
   NA
   NA
   NA
3.OE-02
   NA
                                             7.5E+01 N
                                             1.3E+02 N
2
7
4
9
2
2
8
4
2
4
.OE+04
.8E+00 C
.1E+02 C
.4E+02 C
.OE+04 N
.OE+01 N
.4E+00 C
.1E+02 N
.OE+02 N
.1E+03 N
7. 8E+02
8.7E-01
4 . 6E+01
1. OE+02
7. 8E+02
7. 8E-01
9.4E-01
1. 6E+01
7. 8E+00
1. 6E+02
N
C
C
C
N
N
C
N
N
N
                                                                                                                                1.2E+03 N
                        2.OE+04 N
                        5.2E+01 C
                        1.2E+05 N
                        l.OE+02 N
                        1.OE+04 N
                        4.1E+04 N
                        6.1E+04 N
                        1.OE + 01 N
                        2.0E+03 N
                        1.9E+02 C
                        4.1E+05 N
                       7.8E+02  N
                       5.8E+00  C
                       4.7E+03  N
                       3.9E+00  N
                       3.9E+02  N
                       1.6E+03  N
                       2.3E+03  N
                       3.9E-01  N
                       7.8E+01  N
                       2.1E+01  C
                       1.6E+04  N
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
EPA
          CAS.  = Chemical Abstract Number.
          RfDo = Oral Reference Dose.
          RfDI = Inhalation Reference  Dose.
          CSFo = Oral cancer slope factor  (mg/kg/day)-1
          CSFi = Inhalation cancer slope  factor  (mg/kg/day)-1
             C = Carcinogenic affects.
             N = Noncarcinogenic effects.
                      M =  Action  level  under the  Safe Drinking Water Act.
                    EPA =  Risk-Based  Concentration  Table,  Jan.-Jun 1996. Region III. Philadelphia, PA,
                      V =  Volatile  compound.
                      L =  EPA Region  IX Preliminary Remedial Goal for Lead at Industral Sites. August, 1996.
                ND or  - =  Not determined.
                    NA =  Does  not  apply.
                      0 =  EPA Region  IX Preliminary Remedial Goal for Lead at Residential Sites. August 1996

-------
                                 Table 6-2.   Summary of Screening Values Based  on  Provisional  Toxicity Information.
Contaminant

Inorganic Compounds:
Calcium
Magnesium
Potassium
Sodium
                                                  RfDo
                                                mg/kg/d
  RfDi
mg/kg/d
  Cpso
kgod/mg
  Risk-Based Concentrations
                    Tap
  CPSi             Water
kgod/mg     V       ug/L
Soil Ingestion
     Industrial
        mg/kg
Residential
   mg/kg
                                                                        8.9E+04  N
                                                                        2.2E+04  N
                                                                        2.2E+05  N
                                                                        5.6E+04  N
                                                                           RDA
                                                                           RDA
                                                                           RDA
                                                                           RDA
Organic Compounds:
2-Amino-4,6-dinitrotoluene
4-Amino-2,6-dinitrotoluene
2-Cyclohexen-l-ol
2-Cyclohexen-l-one
Laurie Acid
N,N-diethyl-3-methylbenzamide
2-Propanol
Palmitic Acid
                                                                        1. 1 E + 02  N
                                                                        7.5E+01 N
                                                                        1.7E+01 N
                                                                        1.7E+01 N
                                                                        9.4E+02 N
                                                                        1.6E+02 N
                                                                        6.3E+02 N
                                                                        7.8E+02 N
         CAS.  =  Chemical Abstract Number.
         RfDo  =  Oral  Reference Dose.
         RfDi  =  Inhalation Reference Dose.
         CSFo  =  Oral  cancer slope factor (mg/kg/day)-1
         CSFi  =  Inhalation cancer slope factor (ing/ kg/day) -1
            C  =  Carcinogenic effects.
            N  =  Noncarcinogenic effects.
          EPA  =  Risk-Based Concentration Table,  Jan.-Jun  1996. Region III. Philadelphia,  PA.
            P  =  Provisional RfD based on LD50/100,000 from Registry of Toxic Effects  of  Chemical Substances, 1996.
          RDA  =  Recommended daily allowance for  adult/70  kg to derive an RfD upon which
                to base the RBC.
            L  =  EPA Region IX Preliminary  Remedial  Goal for Lead at Industrial Sites,  August,  1996.
        Prov.  =  Screening level based on provisional RfD.
      ND or  -  =  Not determined.
          NA  =  Does  not apply.

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6.5    Site-Specific Risk-Based Screening Results

To determine the relative significance of the residual site-related contamination detected in
groundwater and soil at each study area, a health-based screening approach was used, as
described previously.  If the site concentrations are deemed significant  (e.g. exceed screening
levels) then these chemicals and associated media are addressed further in a cumulative risk
evaluation.

For soil, the maximum concentrations for each detected compound were compared to the EPA
residential and industrial RBCs and background concentrations.  Even if a chemical exceeds an
RBC, if the concentration is below two-times the site-specific background concentration, then
the chemical is not determined to be site-related and does not require any further action.  In
addition, if a compound is an essential nutrient as outlined by EPA Region IV (e.g., calcium,
chloride, iodine, magnesium, phosphorus, potassium, and sodium) (EPA, 1995), the chemical does
not require further action.

For groundwater, the maximum detected groundwater concentrations  (unfiltered) were compared to
the RBC, MCL, and background concentrations.  As with soils, even if a compound exceeds an RBC
or MCL, if the concentration is below two-times the average background concentration, then the
chemical is not determined to be site-related and does not require any further action.  In
addition, if a chemical is an essential nutrient as outlined by EPA Region TV (e.g., calcium,
chloride, iodine, magnesium, phosphorus, potassium, and sodium), then the chemical does not
require further action.  Finally, if a groundwater constituent is present at levels less than
MCLs, as well as two-times background it is assumed that this chemical would not warrant further
evaluation.  However, if a compound is below an MCL but exceeds two-times background or an RBC,
the compound will be further retained for cumulative risk analysis, because an MCL is not a
purely risk-based value.

The screening results for each study area are summarized in the following subsections.

6.5.1  Salvage Yard

6.5.1.1  Groundwater

As shown in Table 6-3, 13 inorganics and no organics were detected in the one monitor well
(MI035) located downgradient from the Salvage Yard.  Except for cadmium and mercury, all 11
metals reported in Table 6-3 were reported at levels less than MCLs, RBCs, and/or less than
two-times the average site-specific background concentrations established for the site, or were
considered essential nutrients.  The maximum levels detected for cadmium and mercury were
reported in 1983.  Since that time, MI035 was sampled four more times.  Cadmium was targeted for
all four sampling efforts, and mercury was targeted twice and most recently, Cadmium was
detected at a concentration of 3.68 ug/L in September 1988; it was not detected in sampling
events conducted in January 1989, October 1990, and April 1997.  Mercury was not detected in
either of the two sampling events  (October 1990 and April 1997) where it was a targeted analyte.
Results of these analyses show cadmium and mercury to be present at concentrations less than
MCLs and less than two-times the site-specific background concentrations established for the
site.

Because MCLs are not strictly health-based values, concentrations below MCLs are not the
determining factor for supporting a No Further Action recommendation.  To support no further
action for such an instance, these constituents must also be below two-times background or RBCs;
this is the case for barium, cadmium, chromium, copper, mercury, and manganese,  therefore these
chemicals did not require further cumulative risk evaluation.

Based on this information, the groundwater at this site does not required further action.

-------
                                                               Table  6-3.    Comparison of Residual  Groundwater  Contamination at the Salvage  Yard  to MCLs,
                                                                                               Risk-based  Concentrations,  and Background
Analyte
              Maximum
             Cone.  in
           M1035 (ug/L)a
April '97
 Resample
  M1035
 RBC
(ug/L)
  Average
Background++
RBC or MCL
 Exceeded?
   (Y/N)
 Site > 2x
Avg.  Bk g.?
   (Y/N)
Essential
Nutrient?
  (Y/N)
 Health
Concern?
 (Y/N)      <2XBG
Reason for NFA (1)
          ESS
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6.5.1.2  Surface Soil

As shown in Table 6-4, 21 metals and one organic compound were reported in surface soils above
detection limits at the Salvage Yard.  Except for beryllium, cadium, chromium, copper, iron,
lead, thallium, and zinc, concentrations of these compounds were either below the RBCs,
two-times the site-specific background soil concentrations, or the chemical was considered an
essential nutrient.

The 1991 RI concluded that the Salvage Yard was not a source of groundwater contamination  (ICF,
1991).   This conclusion is confirmed when evaluating the soils and groundwater data for the
Salvage Yard.

Based on the information presented in this section  (6.5.1.2), No Further Action cannot be
considered as an appropriate response until a cumulative risk evaluation is performed on the
eight metals exceeding the RBCs in surface soil  (see Sec. 6.6).

6.5.1.3  Subsurface Soil

As shown in Table 6-5, 12 metals and four organic compounds were reported above detection limits
in subsurface soils at the Salvage Yard.  The subsurface site data presented in Table 6-5 were
compared to both residential and industrial RBCs in order to be consistent with the surface soil
screen.  However, as the subsurface soils are deeper than 1 ft,  residential exposure to these
soils is unlikely.  Therefore, the residential RBC was not considered relevant to subsurface
soils.

Except for arsenic, the concentrations of these compounds were either below the industrial RBCs,
two-times the site-specific background soil concentrations, or the chemical was considered an
essential nutrient.

Based on the information presented in this section  (6.5.1.3), No Further Action cannot be
considered as an appropriate response until a cumulative risk evaluation is performed on
arsenic, which exceeded the industrial RBC in subsurface soil (see Sec. 6.6).

6.5.2  Former Ammunition Burnout Area

6.5.2.1  Groundwater

As shown in Table 6-6, 20 inorganic and 6 organic compounds were reported above detection
limits.  Several metals were detected at concentrations exceeding RBCs, MCLs, or two-times the
site-specific background concentrations; however, for reasons explained in Sec. 5.2.2.1 and in
Table 6-6, these elevated levels were considered to be unrepresentative.  When these data were
excluded from consideration, all remaining detected constituents (metals and organic compounds)
were either below two-times the site-specific background concentration, RBCs or less than MCLs,
or were considered acceptable because the constituent was considered an essential nutrient.

Because MCLs are not strictly health-based values, concentrations below MCLs were not the
determining factor for supporting a No Further Action recommendation.  To support no further
action for such an instance, these compounds must also be below two-times background or RBCs.
As shown in Table 6-6, three inorganic compounds  (beryllium, cadmium, and chromium) and one
organic compound  (bis-2-ethylhexylphthalate) were less than their MCLs, but they exceeded
background or RBCs.  Thus, these chemicals were included in a cumulative risk evaluation in
order to determine if groundwater at this area reguires further action.  Nitrobenzene and
1,3.5-trinitrobenzene do not have MCLs; however, these constituents were detected above
background concentrations.  Therefore, these chemicals were also included in the cumulative risk
characterization.
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                                                                             Table 6-4.   Comparison of  Residual  Surface  Soil Contamination  at  the
                                                                                          Salvage Yard to RBCs  and Background  Concentrations
Analyte
                      Maximum                                  RBC
                      Detected         Sample ID               (mg/kg)                  Average
                    Cone,  (ug/g)        (0-1 ft)      Residential     Industrial       Backgrounds-
                                                           Site >
                                                           2x Avg.
                                                            Bkg.?
                                                            (Y/N)
                                           Chemical
                                          Essential
                                          Nutrient?
                                            (Y/N)
   Site>
    RBCs
Res. or Ind.?
    (Y/N)
                                                                                                                                                                     Reason for  NFA
 Health
Concern?
  (Y/N)
  ESS
Nutrient
  Note
Reference
Inorganic  Compounds:
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-1
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-1
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
SYD-2
 200000
   82
  3.8
 14000
  1.3
  100
>1E+06
 1000
 12000
 8200
 61000
 1000
580000
 4700
  61
 4100
>1E+06
 1000
 1000
>1E+06
  16
 1400
61000
Organic Compounds:
RDX
*  Analyte  is below detection; value shown is 1/2  detection limit for  risk-based screening purposes.
+  Background concentration was  obtained from RI  completed by FDI (1996).
1  Although RBC for residential  scenario was exceeded, max, concentration was less than  industrial RBC
2  Included for cumulative risk  evaluation (see  Table 6-12).
3  Included for cumulative HI  evaluation (see Table  6-12).
-------
                                                                 Table  6-5.   Comparison  of  Residual Subsurface  Soil Contamination at the Salvage Yard
                                                                                                to RBCs and Background Concentrations


Analyte
Inorganic Compounds
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
Maximum
Detected
Cone . (ug/g)

11000
1.9*
4.64
139
0.93*
1.52*
854
6.35*
7.5*
29.3*
11000
18
1920
984
0.025*
6.3*
492
0.12*
0.313
414
15.6*
34.5
15. 1*
Sample ID
and
Depth (ft)

SYD-2(5-7 ft)
SYD-l,2(5-7 ft)
SYD-K5-7 ft)
SYD-2(5-7 ft)
SYD-1.2(5-7 ft)
SYD-l,2(5-7 ft)
SYD-1 (5-
SYD-1,2 (
SYD-1, 2 (
SYD-1, 2 (
SYD-1 (5-
SYD-1 (5-
SYD-1 (5-
SYD-1 (5-
SYD-1,2 (
SYD-1, 2 (
ft)
-7 ft)
-7 ft)
-7 ft)
ft)
ft)
ft)
ft)
-7 ft)
-7 ft)
SYD-2(5-7 ft)
SYD-1, 2 (5-7 ft)
SYD-1 (5-7 ft)
SYD-1 (5-7 ft)
SYD-1, 2 (5-7 ft)
SYD-1 (5-7 ft)
SYD-1, 2 (5-7 ft)
                                                                        RBC
                                                                       (mg/kg)
Organic Compounds:
Acetone
2-Propanol
Toluene
Trichlorof1uoromethane
                                                            Residential
                                                                             Industrial
                                                                               200000
                                                                                 82
                                                                                 3.8
                                                                                1400
                                                                                 1.3
                                                                                 100
                                                                               >1E+06
                                                                                1000
                                                                                12000
                                                                                8200
                                                                                61000
                                                                                1000
                                                                               580000
                                                                                4700
                                                                                 61
                                                                                4100
                                                                               >1E+06
                                                                                1000
                                                                                1000
                                                                               >1E+06
                                                                                 16
                                                                                1400
                                                                               61000

Subsurface
Average
Background
5390
BDL
1.73
221
BDL
BDL
234
9.27
1.36
4.33
5730
2.42
370
50.3
BDL
386
251
0.26
BDL
364
BDL
16.1
Site >
2x Avg.
Bkg.?
(Y/N)
Y
N
Y
Y
N
N
Y
N
Y
Y
N
Y
Y
Y
N
N
N
N
Y
N
N
Y
Chemical
Essential
Nutrient?
  (Y/N)
   Site>
   RBCs
Res.  or Ind.?
   (Y/N)
                                                                                                                                                                           Reason for NFA
 Health
Concern?
  (Y/N)
                                                                                                                                                                                      ESS
                                                                                                                                                                                    Nutrient
  Note
Reference
*  Analtye is below detection;  value shown is  1/2 detection  limit for risk-based screening purposes.
+  Background was obtained from RI completed by FBI  (1996).
1  Screening against industrial RBC is considered relevant,  because soils  are deeper than 1 ft;  therefore,  residential exposure to these soils is unlikely.
2  Included for cumulative risk evaluation (see Table 6-13).
-------
                                                                 Table  6-6.   Comparison  of  Residual  Groundwater Contamination at Former  ABA to MCLs,  RBCs,
                                                                                                          and Background Concentrations
Analyte
                          Maximum
                          Detected
                        Cone. (ug/L)*
Monitor
  Well
 RBC
(ug/L)
                RBC or MCL      Site > 2x     Essential      Health             Reason for NFA
 Average         Exceeded?      Avg. Bkg.?     Nutrient?     Concern?                                 ESS         Note
Background+          (Y/N)           (Y/N)          (Y/N)        (Y/N)       <2XBG     
-------
                                                                 Table  6-7.   Comparison of Residual  Surface Soil  Contamination  at  the Former ABA. to  RBCs
                                                                                                         and Background Concentrations


Analyte
Inorganic Compounds :
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc
Maximum
Detected
Cone, (ug/g)

6500
1.9(1.9)*
3.58(15)
1. 69 (1200)
0 93(0 93) *
1.52(1.52)*
15000
6.35* (42)
7.5* (54.2)
29.3(29.3)*
7800 (32000)
80.2
1280
1230 (6690)
0.025 (0.025)*
6.3 (6.3)*
334
0. 125 (0.125) *
0. 0758
348
15. 6 (15. 6)*
80
58.9
Sample ID
and
Depth (ft)

CBG- 1 (0-2 ft)
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-l(0-2 ft ) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft)
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-3(0-2 ft)
CBC-KO-2 ft)
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft)
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft)
CBG-KO-2 ft)
CBG-KO-2 ft) [CREK-1 (0-1
CBG-KO-2 ft)
CBG-KO-2 ft)





ft) ]
ft) ]
ft) ]
ft) ]
ft) ]

ft) ]
ft) ]
ft) ]
ft) ]


ft) ]
ft) ]
ft) ]

ft) ]


ft) ]


Organic Compounds:
Acetone
2-Cyclohexen-l-ol
2-Cyclohexen-l-one
1,2-Epoxycyclohexene
Palmitic acid
Trichlorof1uoromethane
                                                                                    RBC
                                                                                   (mg/kg)
                                                                          Residentia      Industrial
                                                                                          200000
                                                                                            82
                                                                                            3.8
                                                                                           14000
                                                                                            1.3
                                                                                            100
                                                                                          >1E+06
                                                                                           1000
                                                                                           12000
                                                                                           8200
                                                                                           61000
                                                                                           1000
                                                                                          580000
                                                                                           4700
                                                                                            61
                                                                                           4100
                                                                                          >1E+06
                                                                                           1000
                                                                                           1000
                                                                                          >1E+06
                                                                                            16
                                                                                           1400
                                                                                           61000


Average
Background
12478
82
5
99
0.49
1.23
4317
16.2
6. 93
21.36
14833
15
1459
638
0.11
13.1
695
0.29
BDL
225
0.9
27
63
NA
NA
NA
NA
NA
NA
Site >
2x Avg.
Bkg.?
(Y/N)
N
N
N(Y)
N(Y)
N(N)
N(N)
Y
N(Y)
N(Y)
N(N)
N(Y)
Y
N
N(Y)
N(N)
N(N)
N
N(N)
Y
N
Y(Y)
Y
N
NA
NA
NA
NA
NA
NA
Chemical
Essential
Nutrient?
(Y/N)
N
N
N
N
N
N
Y
N
N
N
N
N
Y
N
N
N
Y
N
N
Y
N
N
N
N
N
N
-
-
N
Site >
RBCs Health
Res. or Ind.? Concern?
(Y/N) (Y/N)
N(N) N
N(N) N
Y(Y)/N(Y) N
N(Y)/N(N) N
Y(Y)/N(N) N
N(N)/N(N) N
N/N N
N(Y)/N(N) N
N(N)/N(N) N
N(N)/N(N) N
Y(Y)/N(N) N
N/N N
N/N N
Y(Y)/N(Y) N
N(N)/N(N) N
N(N)/N(N) N
N/N N
N(N)/N(N) N
N/N N
N/N N
N(N)/N(N) N
Y/N N
N/N N
N/N N
N/N N
N/N N
N
N/N N
N/N N
                                                                                                                                                                                          Reason for NFA
                                                                                                                                                                           <2XB  
-------
6.5.2.2  Surface Soil

As shown in Table 6-7, 15 metals and 6 organic compounds were reported above detection limits in
surface soil at the Former ABA.  As shown in this table, one sample collected from the West Fork
of Wolf Creek  (CREK-1) exhibited the highest concentration of inorganic compounds detected at
the Former AEA.  This observation is expected as the creek receives surface runoff from the
site.  However, this single soil sample collected from the dry creek bed is not representative
of potential exposure to the Former ABA study area because the creek is overgrown by brush and
contains water part of the year, such that the actual exposure to the creek bed would be
insignificant compared to the more routine and freguent exposure that would be reasonably
expected to occur on the Former ABA grounds itself.  Thus, for the objectives of the health
evaluation, the maximum value detected in soil collected from the Former ABA (as denoted by CBG
samples reported in Tables 54 and 6-7)  was used to determine if the site soils pose any
potential health concerns.  The concentrations detected in the creek are important to
demonstrate that the creek is a deposition area of site runoff; however, the creek does not
contribute significantly to the overall exposure to the site.

When Sample CREK-1 was included in the data to be evaluated, with the exception of arsenic,
barium, iron, vanadium, and manganese,  all soil constituent levels were either below residential
or industrial health-based levels and/or below two-times the site-specific background
concentrations, or were acceptable because the constituent was considered an essential nutrient.

The 1991 RI concluded that the Former ABA was not a source of groundwater contamination (ICF,
1991).

Based on the information presented in this section (6.5.2), No Further Action cannot be
considered as an appropriate response to surface soil conditions encountered at the Former ABA
until a cumulative risk analysis is performed on barium, iron, vanadium, and manganese (Sec.
6.6) .

6.5.2.3  Subsurface Soil

As shown in Table 6-8, 14 metals and 6 organic compounds were reported above detection limits in
subsurface soil at the Former ABA. The subsurface site data presented in Table 6-8 were compared
to both residential and industrial RBCs in order to be consistent with the surface soil screen.
However, as the subsurface soils are deeper than 1 ft, residential exposure to these soils is
unlikely.  Therefore, the residential RBC was not considered relevant to subsurface soils.

Except for arsenic, the concentrations of these compounds were below the RBCs as well as two
times the site-specific background soil concentrations, or the chemical was considered an
essential nutrient.

Based on the information presented in this section (6.5.2.3), No Further Action cannot be
considered as an appropriate response until a cumulative risk evaluation is performed on arsenic
which exceeded the industrial RBC in subsurface soil  (see Sec. 6.6).

6.5.3  Sanitary Landfill

6.5.3.1  Groundwater

As shown in Table 6-9, 20 metals and 23 organic compounds in groundwater were reported above
detection limits in monitor wells M1062, M1063, M1264, M1266, and M1279.  As stated in Section
5.2.3.1, the other six monitor wells near the landfill  (i.e., 003, 004, M1064,  M1265, M1267, and
M1280)  were considered too deep to be representative monitoring points for landfill groundwater.
Contamination detected at these wells is likely associated with the OBG, which is directly
upgradient from the landfill.  As shown in the Table 6-9, several inorganics were detected above
two-times average background; however,  the levels were either below RBCs or MCLs, or the
chemical is considered an essential nutrient.  Except for bis-2(ethylhexyl)phthalate and several
explosive related compounds, all the remaining organic compounds detected were detected at
levels below RBCs or MCLs.  Although bis-2-ethylhexyl phthalate was detected at several wells
around the Sanitary Landfill area (see Table 5-5), the contaminant has also been detected
-------
                                                 Table  6-8.   Comparison  of  Residual Subsurface  Soil  Contamination  at  the
                                                                           Former  ABA to RBCs  and Background
Analyte
                         Maximum
                         Detected
                       Cone.  (ug/g)
  Sample  ID
     and
  Depth (ft)
  RBC
(mg/kg)
                                                         Residential
                                                                          Industrial
Subsurface
 Average
Background
Site >
2x Avg.
 Bkg.?
 (Y/N)
Chemical
Essential
Nutrient?
 (Y/N)
  Site >
   RBCs
Res.  or Ind.
   (Y/N)
 Health
Concern?
 (Y/N)
                                                                                                                                                             Reason for NFA
                                                                                                         ESS        Note
                                                                                         2XBG  1E+06
                                                                            1000
                                                                            12000
                                                                            8200
                                                                            61000
                                                                            1000
                                                                           .580000
                                                                            4700
                                                                             61
                                                                            4100
                                                                           >1E+06
                                                                            1000
                                                                            1000
                                                                           >1E+06
                                                                             16
                                                                            1400
                                                                            61000
Organic Compounds:
Acetone
2-Cyclohexen-l-ol
2-Cyclohexen-l-one
1,2-Epoxycyclohexene
2-Propanol
CBG-3(10-12  ft)
CBG-2(10-12  ft)
CBG-2(10-12  ft)
CBG-2(10-12  ft)
CBG-3(10-12  ft)
CBG-2(10-12  ft)
Note:       BDL  =  below detection limit.
            NA  =  not available.
            NR  =  not reguired.
           RBC  risk-based concentration.

*  Analyte is below detection; value shown  is  1/2 detection limit for  risk-based screening purposes.
+  Background obtained from the RI conducted by Fluor Daniel for the Southern Area  (1996).
1  Screening against industrial RBC is  considered relevant, because soils  are deeper than 1 ft;  therefore, residential exposure  to  these soils is unlikely
2  Included for cumulative risk evaluation  (see Table 6-13).
3  An RBC could not be calculated for this  constituent. No basis for comparison is available.
-------
upgradient of the Sanitary Landfill in numerous wells.  In fact, M1252 and M1253, upgradient
from the Sanitary Landfill, reported levels of bis-2-ethylhexyl phthalate at levels of 13 and 26
Ig/L, respectively, in October 1994.  The OBG is a documented source of groundwater
contamination in the area and may also be the source of bis-2-ethylhexyl phthalate.

Elevated levels of explosive related compounds and bis-2-ethylhexyl plithalate have also been
detected in monitor wells downgradient from the landfill.  However, explosive-related compounds
and bis-2-ethylhexyl phthalate have also been detected upgradient of the landfill, indicating
that the OBG is a likely source of contamination.  For this reason, bis-2-ethylhexyl phthalate,
RDX, 135TNB, and 246TNT were not considered in the human health evaluation.

Because MCLs are not strictly health-based values, concentrations below MCLs were not
determining factors for supporting a No Further Action recommendation.  To support no further
action for such an instance, these compounds must also be below two-times background or RBCs.
As shown in Table 6-9, two inorganic compounds (beryllium and cadmium) and one organic compound
(chloroform) were less than their MCLs, but they exceeded background or RBCs.  Thus, these
chemicals were included in a cumulative risk evaluation in order to determine if groundwater at
this area requires further action.

6.5.3.2  Surface Soil

As shown in Table 6-10, one inorganic compound (lead) was reported above detection limits while
all organic compounds were below detection in surface soil.  Lead was detected at 17 Ig/g, which
is well below two-times background and the RBCs.


Based on the information presented is this section (6.5.3), No Further Action is considered an
appropriate response to conditions encountered at the Sanitary Landfill.  The basis for the No
Further Action recommendation for each constituent detected in surface soil at the Sanitary
Landfill is presented in Table 6-10.

6.5.3.3  Subsurface Soil

As shown in Table 6-11, 12 inorganic compounds and one organic compound (2-propanol) were
reported above detection limits in subsurface soil at the Sanitary Landfill.  Except for
arsenic, all inorganic compounds and the one organic, 2-propanol, were below RBCs and/or below
two-times the site-specific background concentrations, or were considered an essential nutrient.
Based on these results, arsenic in subsurface soil needs to be further evaluated in a cumulative
risk evaluation to determine if No Further Action is an appropriate response to conditions
encountered in the subsurface soils at the Sanitary Landfill.

6.6    Cumulative Risk Characterization

In the event that a chemical or group of chemicals fails the risk-based screening evaluation,
these chemical(s) are addressed further under the same exposure scenario (e.g., residential,
industrial, and/or construction worker) in a cumulative risk evaluation to determine if the
risks associated with a chemical mixture within a medium pose excess risks.  This evaluation is
used to aid in determining whether a study site requires no further action, or whether remedial
evaluation is necessary.  The methods used in this risk characterization are based on those
presented in EPA risk assessment guidance for human exposures (EPA, 1989,  1991a, 1995c).

6.6.1  Methods for Calculating Carcinogenic Risks

The potential risks associated with exposure to individual carcinogens are calculated by
multiplying the daily chemical intake by the appropriate CSF as follows:

                                         Risk = I * CSF               (6-1)
      where:     Risk =          probability for an individual developing cancer under the
                                 assumed exposure conditions (unitless),
                    I =          daily chemical intake averaged over a lifetime of 70 years
                                  [milligrams per kilogram per day  (mg/kg/day)],
                  CSF =          carcinogenic slope factor, expressed in (mg/kg/day) -1.
-------
                                    Table  6-10.   Comparison of Residual  Surface  Soil Contamination at  the  Sanitary Landfill
                                                                to Risk-based Concentrations and Background
Analyte
                         Maximum
                         Detected
                       Cone.  (ug/g)
Sample ID
   and
  Depth
 RBC
(mg/kg)
                                                      Residential
                                                                    Industrial
              Site >     Chemical      Site>
             2x Avg.     Essential      RBCs         Health
  Average      Bkg.?      Nutrient?   Res.  or Ind.?   Concern?
Backqround+    (Y/N)        (Y/N)        (Y/N)         (Y/N)
                                                                                                                                                               Reason for NFA
                                                                                                                                               <2XBG  1E+06
                                  1000
                                  12000
                                  8200
                                  61000
                                  1000
                                 580000
                                  4700
                                   61
                                  4100
                                 >1E+06
                                  1000
                                  1000
                                 >1E+06
                                   16
                                  1400
                                 61000
Note:   NA = not  available.
       NR = not  reported.
-------
                                                           Table 6-11.   Comparison of Residual Subsurface Soil  Contamination at  the Sanitary  Landfill to
                                                                                              Risk-based Concentrations and Background
Analyte
                         Maximum
                        Detected
                       Cone.(ug/g)
Sample  ID
   and
  Depth
 RBC
(mg/kg)
                                                      Residential
                                                                     Industrial
Subsurface     2x Avg.     Essential        RBCs
  Average       Bkg.?      Nutrient?    Res.  or Ind.?
Background+     (Y/N)        (Y/N)          (Y/N)
Site  >
 Health
Concern?
 (Y/N)
                                                                                                                                                  <2XBG  1E+06
                                                                        1000
                                                                        12000
                                                                        8200
                                                                        61000
                                                                        1000
                                                                       580000
                                                                        4700
                                                                        61
                                                                        4100
                                                                       >1E+06
                                                                        1000
                                                                        1000
                                                                       >1E+06
                                                                        16
                                                                        1400
                                                                        61000
Organic  Compounds:
2-Propanol               0.0095
                                     LF-K5-9  ft)
Note:  BDL = below detection limit.

*  Analyte is below detection:  value shown is 1/2 detection limit for risk-based screening purposes.
+  Background values obtained from  the RI conducted by FBI in  1996.
1  Screening against industrial RBC is considered relevant,  because soils  are deeper than 1 ft; therefore, residential exposure to these soils  is unlikely.
2  Included for cumulative risk evaluation (See  Table 6-13).
-------
As discussed previously, RBCs are chemical concentrations corresponding to fixed levels of risk
 (i.e., a hazard quotient of 0.1, or a lifetime risk of 10 -6, whichever occurs at a lower
concentration) in groundwater and soil.

RBCs are derived by actually running the above risk formula in reverse by solving for the
concentration term in the intake formula, where the intake formula is as follows:



       where:          I  = medium-specific chemical intake (mg/kg/day).
                      C  = chemical  concentration in exposure  medium [milligrams per  liter (mg/L)  or
                         mg/kg].
                     CR  = contact rate;  amount of contaminated medium contacted per  unit time or
                        even (e.g., liters/day; milligrams/day).
                     EF  = exposure  frequency (days/year).
                     ED  = exposure  duration (years).
                     BW  = body weight  (kg) .
                     AT  = averaging time; period over  which exposure  is  averaged (days).

Because an RBC is an "acceptable" exposure concentration for a single compound present in a
single medium and is derived by EPA by running the risk assessment process in reverse,
cumulative risks at a study site can be determined indirectly by ratio to the chemical-specific
RBCs.  In other words, concentrations of chemicals failing the screening evaluation can be
compared, by ratio, to the corresponding RBC to derive the site-specific risk for that chemical
as follows:



       where:         RBC cheml = chemical and medium-specific carcinogenic risk-based concentration
                                   (mg/L  or  mg/kg).
                     TR  cheml =  target  risk associated with RBC (1  x  10  -6).
                     EC  cheml =  maximum detected chemical concentration  at study site;  (mg/L  or
                                 mg/kg).
                     Risk cheml  = site-specific carcinogenic  risk associated with EC (unitless).

Thus, to derive a site-specific risk for each individual chemical failing the screening
evaluation, the above equation is solved for Risk cheml as follows:



The combined risk from exposure to multiple chemicals at a study site is evaluated by addition
of resultant risks from different chemicals as follows:



       where:         Risk T  = the sum of  individual chemical  risks  (unitless probability),  and
                     Risk i  = the risk  estimate for the i th  chemical.

Chemicals failing the residential or industrial health-based screen against surface soils were
evaluated further in a cumulative risk analysis for these exposure scenarios.  Because the
potential exists for future worker exposure to subsurface soils at each study area,  as a result
of excavation/construction work at these areas, chemicals detected in subsurface soils  (e.g.
greater than 2 ft) were evaluated in the cumulative risk analysis using construction worker
exposure assumptions  (see Appendix B).   Because EPA has not established a construction
worker-based RBC, this RBC was calculated  (see Appendix B) and used in the previous formulas to
calculate construction worker cumulative risks associated potential exposure to subsurface soil.

Contaminant concentration levels that present cancer risks that fall within the range of 1 in
1,000,000 to 1 in 10,000  (10 -6 to 10 -4) are generally considered to be acceptable health risks
 [40 Code of Federal Regulations  (CFR)  300, 430:62].  EPA uses the 10 -6 to 10 -4 risk range as a
"target range" within which EPA strives to manage risk as part of Superfund cleanup.  Therefore,
the risk results for each contamination area are summarized to highlight those individual
-------
chemicals and media that exceed the lower bound of the risk range, or 10 -6. The 10 -6 risk
level serves as a starting point, or point-of-departure, to provide focus on those chemicals
that may reguire further evaluation as part of subseguent studies  (i.e., feasibility studies) if
the cumulative site risk exceeds 10 -4.  When a cumulative carcinogenic risk to an individual
under the assumed exposure conditions at the site exceeds 1 in 10,000 (10 -4), CERCLA generally
reguires remedial action at the site  (EPA, 1991c).   When a cumulative risk is less than 10 -4,
action generally is not reguired but may be warranted if a risk-based chemical-specific standard
[e.g., maximum contaminant level (MCL)] is violated, or a risk manager indicates that a lower
risk level must be achieved due to site-specific reasons.  In addition,  remediation may be
reguired due to the presence of unacceptable noncarcinogenic effects or ecological impacts.

6.6.2  Methods for Calculating Noncarcinogenic Risks

Noncarcinogenic health risks are estimated by comparing actual or expected exposure levels to
acceptable or "safe" intakes.  This is accomplished by calculating a noncarcinogenic HQ.  An HQ
is the ratio of chronic daily intake of a contaminant to the RfD for the contaminant and is
calculated as follows:



       where:        I = intake  of  contaminant  (mg/kg/day) ,  and
                     RfD = reference  dose  of  contaminant (mg/kg/day).

I and RfD are expressed in the same units and represent the same exposure period (i.e., chronic,
subchronic, or shorter term).  HQs and His are also estimated for noncarcinogenic chemicals and
potential carcinogens to obtain an assessment for the overall potential for noncarcinogenic
health effects.

As discussed above for calculating cumulative carcinogenic risks, cumulative noncarcinogenic
risks can be derived in the same manner as follows:



       where:        RBC cheml = chemical  and medium-specific  noncarcinogenic risk-based
                                 concentration  (mg/L or mg/kg).
                     THQ cheml = target HQ associated with RBC (0.1).
                     EC cheml =  maximum detected chemical concentration  at  study site;  (mg/L  or
                                mg/kg).
                     HQ cheml =  site-specific HQ associated with EC (unitless).

Thus, to derive a site-specific HQ for each individual chemical failing the screening
evaluation, the above eguation is solved for HQ cheml as follows:



The impact from the presence of multiple chemicals at a contamination area is considered
additive of impacts from individual contaminants.  Thus, the HI is egual to the sum of the HQs:



       where:        I i = Intake for the  i th  toxicant (mg/kg/day),  and
                     RfD i = reference dose for the i th toxicant (mg/kg/day).

When the cumulative HI exceeds unity  (1.0), there may be concern for potential health effects.
An HQ or HI egual to or less than 1.0 indicates that it is unlikely for even sensitive
populations to experience adverse health effects (EPA, 1989).   Any single chemical with an HQ
exceeding 1 will cause the HI to also exceed 1.  In addition,  although the HQs for all chemicals
evaluated for a particular medium and pathway may be less than 1, addition of the HQs may result
in an HI that exceeds the target HI.

6.6.3  Site-Specific Cumulative Risk Results

Based on the risk screening results,  the Salvage Yard and Former ABA reguire a cumulative risk
-------
evaluation for the surface soil while all three areas  (Salvage Yard, Former ABA, and Sanitary
Landfill) require a cumulative risk evaluation for subsurface soils.  For groundwater, only the
Former ABA and Sanitary Landfill required a cumulative risk evaluation.

Using the risk evaluation methods described previously, estimates of potential carcinogenic
risks and noncarcinogenic His were obtained for the chemicals that failed the screening
evaluation for each study site.  The carcinogenic risk estimates were compared to the target
cumulative risk range of 10 -6 to 10 -4, while noncarcinogenic His were compared to the target
HI of 1.0 (unity), above which there may be concern for potential adverse health effects.
Because several chemicals detected in groundwater, surface soil, and subsurface soil failed the
screening evaluation, a cumulative risk assessment was conducted for these three media.

A discussion of the human risk and HI results for each study site is presented in the following
sections.  Potential cumulative carcinogenic risks and noncarcinogenic His associated with
exposure to the COCs under the future residential exposure to surface soil are presented in
Tables 6-12 and 6-13 for the Salvage Yard and Former ABA, respectively.  The cumulative risk
construction exposure to subsurface soil at the Salvage Yard, Former ABA, and Sanitary Landfill
are presented in Table 6-15.  In addition, cumulative risks results associated with potential
exposure to groundwater at the Former ABA and Sanitary Landfill are presented in Table 6-16.

6.6.3.1  Salvage Yard

Tap Water (groundwater)
Based on the results of the risk-based screen, none of the residual contamination in the Salvage
Yard groundwater exceeded RBCs or two-times background, Therefore, a cumulative risk evaluation
was not required for groundwater at this study site.

Residential Scenario (surface soil)
Based on the results of the surface soil screening evaluation, eight chemicals  (all inorganic
compounds) were retained for cumulative risk evaluation  (See Table 6-12).  As shown in Table
6-12, the cumulative carcinogenic risk calculated for residential exposure to the carcinogenic
chemicals is 1.1 x 10 -5, which is within EPA's cumulative target risk range of 10 -6 to 10 -4.

According to EPA risk assessment guidance (EPA, 1989), if the cumulative HI of all COCs result
in an exceedance of the target HI of 1, EPA recommends segregating the contributions of the
different chemicals according to major effect, whereby individual HQs are only added within the
same target organ/system.  Based on target effects, the HI associated with gastrointestinal (GI)
effects due to the presence of copper in surface soil is 4.2; the HI due to blood effects is 6.3
due to zinc and thallium; and the HI due to liver effects is 2 due to iron.

Industrial Worker Scenario  (surface soil)
Based on the results of the surface soil screening evaluation, three compounds  (beryllium,
copper, and thallium) were retained for cumulative risk evaluation.  Beryllium exceeded the
carcinogenic-based RBC of 1.3 mg/kg, while copper and thallium exceeded the
noncarcinogenic-based RBCs of 8,200 and 16 mg/kg, respectively.

As shown in Table 6-14,  the cumulative carcinogenic risk calculated for industrial exposure to
beryllium in surface soil is 1.3 x 10 -6, which is well within EPA's cumulative target risk
range of 10 -6 to 10 -4.

For noncarcinogenic effects, the cumulative HI associated with industrial exposures to copper
and thallium in surface soil is 0.4, which is below the target HI of 1, indicating that chronic
adverse health effects should not result based on the exposure assumptions evaluated.

Construction Worker Scenario (subsurface soil)
Based on the results of the subsurface soil screening evaluation, one compound  (arsenic)  was
retained for cumulative risk evaluation. Arsenic exceeded the carcinogenic-based RBC of 3.8
mg/kg with a detected concentration of 4.64 mg/kg.

As shown in Table 6-15,  the cumulative carcinogenic risk calculated for construction worker
exposure to arsenic in subsurface soil is 1.2 x 10 -7, which is below EPA's cumulative target
risk range of 10 -6 to 10 -4.
-------
                           Table  6-12.   Summary of Risks and His for Chemicals Detected in Surface Soil
                                    at Salvage Yard Exceeding RBCs  Based On Residential Exposure



Area Analyte
Salvage Yard Beryllium
Copper
Cadmium
Chromium
Iron
Lead
Zinc
Thallium
Maximum
Detected
Concentration
(ug/g)
1.63
12900
29.5
75.2
45200
639
2495
39.1
                                              Residential RBC
                                             Risk=lE-06   HQ=0.1
           Residential
      Risk Characterization
Site Risk     Site-HQ     Target Organ
0.15
NA
NA
NA
NA
NA
NA
NA
NE
310
3.9
39
2300
400*
2300
0.63
1.09E-05
NA
NA
NA
NA
NA
NA
NA
NE
4.2
0.76
0.19
2.0
0.28 *
0.11
6.2
Bone
GI
Kidney
Kidney
Liver
CNS
Blood
Blood/liver
                                                                  TOTAL 1.1E-05       +

 The lead HQ is based on comparing the maxium site concentration to the residential screening level.
 Individual HQs are only additive for target organs/systems;  none of the target organ/system totals exceed 1.
Source:  QST.
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Area
                       Table 6-13.  Summary of Risks and His for Chemicals Detected in Surface Soil at the
                                     Former ABA. Exceeding RBCs  Based on a Residential  Exposure
                       Exposure Concentration
                       Maximum Detected  (ug/g)
         Analyte
                           Creek
                                      Yard
                                                  CSForal
                                                             RfDoral

Former
ABA






Arsenic
Barium
Thallium**
Beryllium**
Chormium**
Iron
Vanadium
Manganese

15
1200
7.8
0.93
0.42
32000
80
6690

3.58
1.69
7.8
0.93
0.42
7800
80
1230

1.5
NA
NA
4.3
NA
NA
NA
NA
TOTAL SITE
0.0003
0.07
8E-05
0.005
0.005
0.3
0.007
0.023
RISK
    Residential
    Risk Characterization*
Site Risk     Site-HQ
1.


6.





, 4E-05
NA
NA
,3E-06
NA
NA
NA
NA
2E-05
0.13
0.0002
1.0
0.004
0.0009
0.27
0.12
0.55
+
Target Organ/System

Skin
Blood/Circulatory
Blood/Circulatory
Bone
Kidney
Liver
GI
CNS
 * Site-specific exposures assumes that a child is exposed to the creek soil 20% of the total exposure;
   the remaining 80% of the soil exposure occurs at the remaining area.
** Analyte was below detection, the concentration presented is one-half of the detection limit.
 + Individual HQs are only additive for target organs/systems; none of the target organ/system totals exceed 1.

Source: QST.
p/mlaap/rod/tab!2.wm2
-------
                   Table  6-14.  Summary of Risks and His for Chemicals Detected in Surface Soil Exceeding RBCs
                                                   Based on Industrial Exposure
                               Maximum
                               Detected
                                             Industrial RBC
      Industrial
Risk Characterization
Area
Salvage Yard
Former ABA
Analyte
Beryllium
Copper
Thallium
Arsenic
Manganese
Cone . (ug/g)
1.63
12900
39.1
15
6690
Risk=lE-06
1.3
NA
NA
3.8
NA
HQ=0.1
NE
8200
16
NE
4700
Site Risk
1.2E-06
NA
NA
TOTAL 1.2E-06
3.9E-06
NA
Site- Hi
NE
0.16
0.24
0.40
NE
0.14
                                                                 TOTAL  3.9E-06
                                                                                      0.14
Source:   QST.
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                    Table 6-15.  Summary of Risks and His for Chemicals Detected in Sub-Surface Soil Exceeding
                                                RBCs Based on Construction Exposure
Area

Salvage Yard


Former ABA
            Maximum        Construction RBC*
            Detected
Analyte   Cone, (ug/g)   Risk=lE-06   HQ=0.1
Arsenic
Arsenic
Sanitary Landfill   Arsenic
                4.64
                                    9.91
                5.52
                              39.5
                                                  39.5
                              39.5
     Construction

Site Risk     Site-HQ
NE
TOTAL
NE
TOTAL
NE
TOTAL
1
1
2
2
1
1
.2E-07
.2E-07
.5E-07
.5E-07
.4E-07
.4E-07
NE
NE
NE
NE
NE
NE
* Derived based on exposure assumptions presented in Appendix B-l.

Source:  QST.
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                        Table 6-16.  Summary of Risks and His for Chemicals Detected in Groundwater Below
                                       MCLs but Exceeding RBCs or Background Concentrations
Area

Former ABA
Analyte

Beryllium
Cadmium
Chromium
Bis-2-ethylhexylphthalate
Nitrobenzene
1,3,5-Trinitrobenzene
  Maximum        Tap Water RBC
  Detected
Cone. (ug/L)    Risk=lE-06  HQ=0.1
                                                                                               Potable Use Risk
                                                                                               Characterization
                                                                                            Site Risk      Site HI
0.65
3.14
36.1
5.7
0.596
0.285
0.016
NA
NA
4.8
NA
NA
NE
1.8
18
NE
0.34
0.18
4.1E-05
NA
NA
1.2E-06
NA
NA
NE
0.17
0.20
NE
0.18
0.16
                                                                                        TOTAL  4.2E-05
                                                                                                            0.71
Sanitary Landfill
Beryllium
Cadmium
Bis-2-ethylhexylphthalate
Chloroform
1.54
4.08
52
2.6
0.016
NE
4.8
0.15
NE
1.8
NE
NE
9.6E-05
NA
1.1E-05
1.7E-05
NE
0.23
NE
NE
                                                                                        TOTAL  1.2E-04
                                                                                                            0.23
Source:  QST.
-------
6.6.3.2  Former Ammunition Burnout Area

Tap Water  (groundwater)
Based on the results of the risk-based screen, three inorganic compounds  (beryllium, cadmium,
and chromium) and three organic compounds  (nitrobenzene, 1,3,5-trinitrobenzene, and
bis-2-ethylhexylphthalate) reguire cumulative risk evaluation due to their presence in
groundwater at concentrations exceeding two-times background or RBCs. Thus, these chemicals were
included in a cumulative risk evaluation in order to determine if groundwater at this area
reguires further action.

As shown in Table 6-16, the cumulative carcinogenic risk of 4.2 x 10 -5 associated with potable
use of groundwater containing beryllium and bis-2-ethylhexylphthalate at maximum concentrations
of 0.65 and 5.7 Ig/L, respectively, is within EPA's cumulative target risk range of 10 -6 to 10
-4.  For noncarcinogenic effects, the cumulative HI associated with potable use of groundwater
containing cadmium, chromium, NB, and 135TNB at maximum concentrations of 3.14, 36.1, 0.506, and
0.285 Ig/L, respectively, is 0.71, which is below the target HI of 1, indicating that chronic
adverse health effects should not result based on the exposure assumptions evaluated.

Residential Scenario (surface soil)
Based on the results of the surface soil screening evaluation, eight inorganic compounds were
retained for cumulative risk evaluation (see Table 6-13).   Because there are samples that
represent two discrete exposure areas within the Former ABA  (Ammunition Burnout Area), this area
was evaluated to address the potential of a child to be exposed to both areas during play
activities.  Exposure was evaluated by the percent of time a child would be expected to play in
the creek area versus the time spent in the remaining area that is considered to be
representative of a residential yard.  The conservative assumption was made that 20 percent of
the exposure would be in the creek while 80 percent of the exposure time would be in the yard.
As shown in Table 6-13, the cumulative carcinogenic risk calculated for residential exposure to
both areas is 2.0 x 10 -5, which is within EPA's cumulative target risk range of 10 -6 to 10 -4.

According to EPA risk assessment guidance  (EPA, 1989),  if the cumulative HI of all COCs result
in an exceedance of the target HI of 1, EPA recommends segregating the contributions of the
different chemicals according to major effect, whereby individual HQs are only added within the
same target organ/system.  Based on target effects, none of the His associated with target
organ/systems were above 1.

Industrial Worker Scenario (surface soil)
Based on the results of the surface soil screening evaluation, two chemicals were retained for
cumulative risk evaluation to include arsenic and manganese.  Arsenic exceeded the carcinogenic-
based RBC of 3.8, while manganese exceeded the noncarcinogenic-based RBCs of 4,700 mg/kg.

As shown in Table 6-14, the cumulative carcinogenic risk calculated for industrial exposure to
arsenic in surface soil is 3.9 x 10 -6, which is well within EPA's cumulative target risk range
of 10 -6 to 10 -4.

For noncarcinogenic effects,  the cumulative HI associated with industrial exposures to manganese
in surface soil is 0.14, which is well below the target HI of 1, indicating that chronic adverse
health effects should not result based on the exposure assumptions evaluated.

Construction Worker Scenario (subsurface soil)
Based on the results of the subsurface soil screening evaluation, one compound (arsenic) was
retained for cumulative risk evaluation.  Arsenic exceeded the carcinogenic-based RBC of 3.8
mg/kg with a detected concentration of 9.91 mg/kg.

As shown in Table 6-15, the cumulative carcinogenic risk calculated for construction worker
exposure to arsenic in subsurface soil is 2.5 x 10 -7,  which is below EPA's cumulative target
risk range of 10 -6 to 10 -4.

6.6.3.3  Sanitary Landfill

Tap Water  (groundwater)
Based on the results of the risk-based screen, two inorganic compounds, beryllium and cadmium,
-------
and the organic compound, chloroform, require cumulative risk evaluation due to their presence
in groundwater at less than the MCLs, but exceeding two-times background or RBCs.  Thus, these
chemicals were included in a cumulative risk evaluation in order to determine if groundwater at
this area requires further action.

As shown in Table 6-16, the cumulative carcinogenic risk of 1.2 x 10 -4 associated with potable
use of groundwater containing beryllium, bis-2-ethylhexylphthalate, and chloroform, slightly
exceeds EPA's upperbound of the cumulative target risk range of 10 -6 to 10 -4.  For
noncarcinogenic effects, the cumulative HI associated with potable use of groundwater containing
cadmium at maximum concentration of 4.08 Ig/L is 0.23, which is below the target HI of 1,
indicating that chronic adverse health effects should not result based on the exposure
assumptions evaluated.

Residential Scenario  (surface soil)
Based on the results of the surface soil screening evaluation, none of the chemicals exceeded
the residential health-based screening levels; therefore, a residential cumulative risk
evaluation was not required for this area.

Industrial Worker Scenario (surface soil)
Based on the results of the surface soil screening evaluation, no chemicals were retained for
further cumulative risk evaluation because none of the chemicals failed the industrial soil
screening evaluation.  Thus,  the Sanitary Landfill is not included in the cumulative risk
results presented in Table 6-14.

Construction Worker Scenario (subsurface soil)
Based on the results of the subsurface soil screening evaluation, one chemical, arsenic, was
retained for cumulative risk evaluation.  Arsenic exceeded the carcinogenic-based RBC of 3.8
mg/kg with a detected concentration of 5.52 mg/kg.

As shown in Table 6-15, the cumulative carcinogenic risk calculated for construction worker
exposure to arsenic in subsurface soil is 1.4 x 10 -7, which is below EPA's cumulative target
risk range of 10 -6 to 10 -4.

6.7    Summary of Risk Screen and Cumulative Risk Results

A screening evaluation was conducted to eliminate chemicals from further cumulative risk
analysis, as chemicals passing the screen are not considered to contribute significantly to
overall cumulative study site risks.  Several chemicals detected in groundwater at two of the
three study sites failed the screening evaluation, and thus groundwater, was included for
further risk evaluation.  In addition, several chemicals failed the soil screening evaluation
for all three study sites, such that soil, both surface and subsurface, was included for further
cumulative risk evaluation.  Table 6-17 summarizes the results of the risk screening and
cumulative risk assessment.

6.7.1  Groundwater

The groundwater screening evaluation conducted at the Salvage Yard indicated that none of the
detected chemicals in groundwater failed the screening such that further cumulative risk
evaluation for groundwater at this site was not required.  At the Former ABA, beryllium,
cadmium, chromium, bis-2-ethylhexylphthalate, NB, and 135TNB were present in groundwater above
screening levels.  At the Sanitary Landfill, beryllium, cadmium, and chloroform, exceeded
screening levels.  Based on the cumulative risk evaluation of groundwater for the Salvage Yard
and Former ABA, the cumulative risks are within EPA's cumulative risk range and the cumulative
HI is below 1.  Based on the cumulative risk evaluation at the Sanitary Landfill, the cumulative
HI is less than 1; however, cumulative risks slightly exceed 10 -4.
-------
        Table 6-17.   Justification of No Further Action (NFA) for All Media at the Study Areas
Study Area

Salvage Yard



Former ABA
Sanitary
Landfill
      NFA
    Based on
    Screening

Groundwater
(Residential use)
All media failed
screening and
reguire
cumulative risk
assessment
Surface Soil
(Residential)

Surface Soil
(Industrial)
             NFA
     Based on Cumulative
       Risk Assessment

Surface Soil (Industrial)

Subsurface Soil (Construction)

Groundwater (Residential)

Surface Soil (Residential)

Surface Soil (Industrial)

Subsurface Soil (Construction)

Groundwater (Residential)

Subsurface Soil (Construction)
                                                         Media Exceeding
                                                         Cumulative Risk

                                                       Surface Soil  (Residential)
                                                                         None
                                                        None
Note:  Surface soil = 0 to 2 feet; Subsurface soil = >2 feet.

Source:  QST.
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6.7.2  Soil

6.7.2.1  Salvage Yard

The screening of surface soils at the Salvage Yard indicated a total of eight metals exceeded
the residential based screening levels; three metals exceeded the industrial based screening
levels for surface soils; and one metal (arsenic) exceeded for subsurface soil.  The results of
the cumulative risk evaluation for the industrial and construction worker scenario indicate that
the residual chemical concentrations in surface and subsurface soil are below or within EPA's
cumulative target risk range of 10 -6 to 10 -4, or below the target HI of 1 for the industrial
and construction worker scenario's.

Cumulative residential risk was also within EPA's cumulative target risk range.  However, based
on target effects, the HI associated with GI effects due to the presence of copper in surface
soil in 4.2; the HI due to blood effects is 6.3 due to zinc and thallium; the HI due to liver
effects is 2 due to iron.

Although the His associated with target organs exceed 1 for only the future residential scenario
associated with surface soil (i.e., His range from <1 to 6), these HI values have been derived
based on a number of conservative assumptions regarding exposure and toxicity to ensure that the
evaluation is over protective rather than under protective.  Regarding toxicity, the His are
based on the use of EPA-derived toxicity values, or RfDs, that incorporate a guantitative
uncertainty.

The primary source of this uncertainty is the derivation of RfDs from animal laboratory studies
due to the limited data available from clinical human studies.  To ensure the protection of
human health, however, EPA applies a number of uncertainty factors to the animal data to account
for its use in assessing human health.  The total uncertainty factors usually range from 1 to
over 1,000 with the higher uncertainties associated with studies that are less confident or are
associated with animal effects that are not readily extrapolated to humans.

As previously stated, eight metals in surface soils exceeded screening levels  (beryllium,
cadmium, chromium, copper, iron, lead, thallium, and zinc). Four of these metal contributed to
an exceedance of a target HI of 1 in a target organ/system  (copper, iron, thallium, and zinc),
while the other four metals  (beryllium, cadmium, chromium,  and lead) were determined to be
present at concentrations that did not warrant further concern.

The uncertainty factors applied to the toxicity values for the four metals that contributed to
an exceedance of a target HI of 1 in a target organ/system are 2 (for copper), and 3 (for zinc),
1,000 (for iron), and 3,000  (for thallium).  In addition to the uncertainty factor of 2 for
copper,  additional uncertainty is associated with the HI calculation because the RfD used for
copper was not derived by EPA but was back-calculated from the maximum contaminant level goal
(MCLG) for copper in drinking water.  Thus, the additional uncertainty for copper is related to
applying a RfD based on groundwater consumption to an exposure pathway based on soil ingestion.

In summary, although several metals contributed to an exceedance of a target HI of 1, the
uncertainty factors incorporated in the human toxicity values suggest that exposure to soils at
the Salvage Yard may not result in any adverse systemic effects.

6.7.2.2  Former ABA

The screening of surface soils at the Former ABA indicated a total of five metals exceeded the
residential based screening levels  (an additional three were added because detection limits were
greater than screening levels); two metals exceeded the industrial based screening levels for
surface soils; and one metal (arsenic) exceeded for subsurface soils.  The results of the
cumulative risk evaluation indicate that the residual chemical concentrations in surface and
subsurface soil are below or within EPA's cumulative target risk range of 10 -6 to 10 -4, for
all three scenarios evaluated.   In addition, the noncarcinogenic evaluation indicates that His
for target effects are below 1 for residential exposure and cumulative His for industrial and
construction workers are less than 1.

6.7.2.3  Sanitary Landfill
-------
The Screening of surface soils at the Sanitary Landfill indicated no metals exceeded the
residential or industrial based screening levels in surface soils.  One metal,  arsenic,  exceeded
the subsurface soil screening level.  Based on a residential land use,  however,  the results of
the cumulative risk evaluation indicated that the residual arsenic concentration in subsurface
soil is below EPA's cumulative target risk range of 10 -6 to 10 -4, based on a more realistic
construction scenario.
-------
7 . 0    Basis for NFA Recommendation

As discussed in Section 6.0, the majority of constituents detected in the various media at the
Salvage Yard, Former ABA,  and Sanitary Landfill passed the Health Evaluation screening process
and therefore, no further action is reguired for these constituents.  If a COPC could not be
recommended for NFA based on the health screen, the COPC was retained to assess cumulative
risks.  Based on the health based screening and results of the cumulative risks, an NFA
recommendation was justified for all areas, with the exception of the residential scenario use
of groundwater at the Sanitary Landfill and soil at the Salvage Yard.

Groundwater at the Sanitary Landfill
As previously stated, if a chemical passes the screening process  (the cumulative carcinogenic
risk is less than 10 -4 and the cumulative non-carcinogenic risk is less than 1), no further
action is reguired.  However, when a cumulative risk threshold is exceeded, it does not
necessarily mean that remedial action is reguired.  Other factors and information need to be
considered in addition to cumulative risk.

The cumulative risk as the Sanitary Landfill is 1.1 x 10 -4.  Beryllium contributes
approximately 87 percent of the total potential carcinogenic risk estimated for this site.  The
maximum detected concentration of beryllium was 1.54 Ig/g.  The MCL  (i.e., the primary drinking
water standard)  for beryllium is 4 Ig/L and corresponds to a carcinogenic risk of 2.5 x 10 -4.
MCLs are promulgated by law.  When an MCL is defined, numerous factors such as health effects
and costs for compliance are considered.  The fact that the MCL for beryllium exceeds the
upper-bound risk of 1 x 10 -4 shows that it is not practicable to achieve the 1 x 10 -4 risk
concentration for beryllium.

The MCLs for the COPCs evaluated for cumulative risk at the Sanitary Landfill are:

            Beryllium - 4 Ig/L,
       •    Cadmium - 5 Ig/L,
       •    Chloroform - 100 Ig/L (based on total halocarbons).

The maximum concentrations for the Sanitary Landfill groundwater are less than the above MCLs
for beryllium, cadmium, and chloroform.

Bis-2-ethylhexyl phthalate,  RDX, 135TNB, and 246TNT were detected at elevated levels in
groundwater downgradient from the Sanitary Landfill.  However, these constituents were also
detected upgradient as well.  These constituents have been detected in monitor wells for the OBG
and will be addressed with the OBG plume as part of the site-wide groundwater operable unit and
the southern study area operable unit.

When considering the above factors (cumulative risk, risks associated with MCLs, the fact that
some COPCs in groundwater at the Sanitary Landfill are less than MCLs, and upgradient sources of
contamination),  a no further action recommendation for groundwater at the Sanitary Landfill is
appropriate.

Soil at the Salvage Yard
Although the HI of 1 was exceeded under the residential scenario for surface soil at the Salvage
Yard, the residential scenario is not considered applicable to MLAAP.  Since MLAAP currently
fulfills a critical mission that will be necessary as part of future Army operations, and it is
Army practice to clean up to the current land use scenario, no clean-up decisions were based on
the future residential use scenario.   Given this, and considering that the industrial use and
construction use scenario's did not pose unacceptable risks, a no further action recommendation
for surface soil at the Salvage Yard is appropriate.

Access to the Salvage Yard is restricted by fence and gate.  If, in the future, MLAAP would be
subject to base closure, or access to the Salvage Yard became unrestricted, site-related risk
would be re-evaluated in accordance with DoD base closure policy  (10 U.S.C. 2687 and NOTE).
-------
                                                  References

Environmental Resources Management, Inc.  (ERM). 1995. Final Milan Army Ammunition Plant Remedial
       Investigation, DU4 Northern Study Area, ELIN A013. Prepared for the U.S. Army
       Environmental Center, Aberdeen Proving Ground, MD.

Environmental Science & Engineering, Inc.  (ESE). 1996. Proposed Plan  (In Production).  Prepared
       for the U.S. Army Environmental Center, Aberdeen Proving Ground, MD.

Fluor Daniel, Inc.  (FDI). 1996. Milan Army Ammunition Plan, Remedial  Investigation,  Southern
       Study Area  (Operable Unit No. 5). Prepared for the U.S. Army Environmental Center.
       Aberdeen Proving Ground, MD.

ICF Kaiser Engineers, Inc.  (ICF). 1991.  Remedial Investigation for Milan Army Ammunition Plant.
       Prepared for the U.S. Army Environmental Center.  Aberdeen Proving Ground, MD.

U.S. Environmental Protection Agency  (EPA). 1996. Risk-Based Concentration Table, January - June
       1996.  Prepared by R.L. Smith,  Technical Support Section,  EPA Region III, Philadelphia,
       PA. April 19, 1996.

U.S. Environmental Protection Agency  (EPA). 1995. Supplemental Guidance to RAGS:  Region 4
       Bulletins.  Waste Management Division,  Office of Health Assessment,  EPA Region IV,
       Atlanta,  GA. November 1995.

U.S. Environmental Protection Agency  (EPA). 1993. Region III Technical Guidance Manual for Risk
       Assessment:  Selecting Exposure Routes and Contaminants of Concern by Risk-Based
       Screening.  Hazardous Waste Management Division,  Office of Superfund Programs,
       Philadelphia, PA.

U.S. Environmental Protection Agency  (EPA). 1991. Risk Assessment Guidance for Superfund  (RAGS).
       Volume 1:  Human Health Evaluation Manual, Part B (Development of Risk-Based Preliminary
       Remediation Goals).  Office of Emergency and Remedial Response, Washington, DC. OERR
       9285.7-01B.

U.S. Environmental Protection Agency  (EPA). 1989. Risk Assessment Guidance for Superfund  (RAGS).
Volume 1:  Human Health Evaluation Manual, Part A. Office of Emergency and Remedial  Response,
Washington, DC.  EPA/540/1-89/002.
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                                                  Appendix A

                                            Responsiveness Summary

The purpose of the Responsiveness Summary is to provide the public with a summary of citizen
comments, concerns, and questions about the Salvage Yard, Former Ammunition Burnout Area   (ABA),
and Sanitary Landfill.

The Final Proposed Plan for the Salvage Yard, Former ABA, and Sanitary Landfill was released  to
the public in November 1997.  A public availability session announcement for the meeting was
published in the Milan Mirror Exchange and Jackson Sun in November 1997.

The public availability session was held on December 4, 1997, at the Tom C. McCutchen
Agricultural Museum.  At this meeting, representatives of the Army, EPA, and TDEC were
available to summarize the information presented in the Proposed Plan, discuss the rationale for
selecting No Further Action as the preferred alternative, and discuss any site-related issues
raised  by the public.

No written comments were received during the 30-day public comment period.  In addition, no
verbal comments were presented during the December 4, 1997 public availability session.
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                             Appendix B
                            Appendix B-l
         Health Based-Screening Equations and Methodologies
                            Appendix B-2
Exclusion of Inhalation and Dermal Exposure Pathways as Insignificant
                            Appendix B-3
                         Toxicity Assessment
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                                                 Appendix B-l
                             Health Based - Screening Equations and Methodologies
                                   EEC SAMPLE CALCULATIONS FOR GROUNDWATER,
                                       SURFACE  SOIL, AND  SUBSURFACE  SOIL

                                                GROUNDWATER RBC

Sample calculations for deriving both a noncarcinogenic and carcinogenic-based groundwater RBCs
are provided in the following sections.

Carciogenic Effects
The generalized formula for calculating RBCs based on carcinogenic effects is as follows:



        where:        RBC gw = Risk-based concentration for groundwater  (ug/L)
                          TR = target risk  (unitless).
                        BW a = adult body weight  (kg).
                        AT c = averaging time for carcinogenic exposures  (days per lifetime).
                          EF = exposure freguency (days/year).
                     IFA adj = age-adjusted tap water ingestion rate  (L-yr/kg-day).
                       CSF o = oral cancer slope factor  [(mg/kg/day) -1].
                       CSF i = inhalation cancer slope factor [(mg/kg/day) -1]
                     IFW adj = age-adjusted inhalation factor (L-yr/kg-day).
                          FC = factor to convert groundwater concentration from mg/L to ug/L.
                           K = volatilization factor (L/m 3).

Substituting the relevant exposure assumptions and toxicity dose-response values into eguation
the groundwater carcinogenic-based RBC for chloroform is calculated as follows:


        where:            TR = IE-06.
                          BW = 70 kg.
                        AT c = 25550 days/lifetime.
                          EF = 350 days/year.
                          ED = 30 yrs.
                       IR gw = 2 L/day.
                       CSF o = 0.0061  (mg/kg/day) -1
                       CSF i = 0.081  (mg/kg/day) -1
                           K = 0.5 L/m 3.
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                                          GROUNDTSATER RBC (continued)

All exposure factors and toxicity factors were provided by the EPA Region III Risk-Based
Concentration Table  (EPA, 1997).  For nonvolatile compounds, such as arsenic, do not address the
volatilization portion of the RBC equation which is CSF i x K x IFA adj.

Noncarcinogenic Effects
The generalized formula for calculating groundwater RBCs based on noncarcinogenic effects is as
follows:


        where:       RBC gw = noncarcinogenic risk-based concentration  (ug/L).
                        THQ = target hazard quotient  (0.1).
                       BW a = adult body weight  (kg).
                       AT n = averaging time for noncarcinogenic exposures  (ED x 365 days/year)
                         EF = exposure frequency  (days/year).
                         ED = exposure duration  (years).
                      IRW a = intake rate for groundwater  (L/day).
                      RfD o = oral reference dose  (mg/kg/day).
                      RfD o = inhalation reference dose  (mg/kg/day).
                      IRA a = inhalation rate (m 3/day).
                         FC = factor to convert groundwater  concentration in mg/L to ug/L.
                          K = volatilization factor (L/m 3).

Substituting the relevant exposure assumptions and toxicity  dose-response values into equation
(3), the groundwater noncarcinogenic-based RGO for ethylbenzene is  calculated as follows:


        where:
                        THQ =0.1.
                         BW = 70 kg.
                       AT n = 30 years x 365 days/year or 10950 days.
                         EF = 350 days/year.
                         ED = 30 years.
                      IRW a = 2 L/day.
                      RfD o = 0.1 mg/kg/day.
                      RfD i = 0.29 mg/kg/day.
                      IRA a = 20 m 3/day.
                         FC = 1000 ug/mg.
                          K = 0.5 L/m 3.
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                                               SURFACE SOIL RBC

Sample calculations for deriving both a carcinogenic and noncarcinogenic-based RBCs in soil are
provided in the following sections.  Samples were provided for the three scenarios evaluated in
the risk-based Screen to include:  residential, industrial, and construction.

Residential-Carcinogenic
The generalized formula for calculating a residential-based RBC based on carcinogenic effects is
as follows:


        Where:
                         TR = target risk  (unitless).
                       BW a = adult body weight  (kg).
                       AT c = averaging time for carcinogenic exposures  (days per lifetime)
                         EF = exposure freguency (days/year).
                         FC = soil conversion factor  (kg/mg).
                      CSF o = oral cancer slope factor  [(mg/kg/day) -1].
                    IFS adj = age-adjusted intake rate for soil  (mg-yr/kg-day).
Substituting the relevant exposure assumptions and toxicity dose-response values into eguation
the soil residential carcinogenic-based RBC for arsenic is calculated as follows:

        where:           TR = 1E-06.
                         BW = 70 kg.
                         FC = 1,000,000 mg/kg.
                      CSF o = Oral cancer slope factor  [(mg/kg/day) -1].
                    IFS adj = 114..29  (mg-yr/kg-day).
                       AT c = 25550 days/lifetime.
                         ED = 30 yrs.
Note, all exposure factors and toxicological factors were provided by the EPA Region III
Risk-Based Concentration Table (EPA, 1997).
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                                         SURFACE SOIL RBC (continued)

Resident!al-Noncarcinogenic
The generalized formula for calculating residential soil RBCs based  on noncarcinogenic effects
is as follows:


        where:       RBC a = noncarcinogenic risk-based concentration (ug/L).
                       THQ = target hazard guotient (0.1).
                      BW c = body weight of a child (kg).
                      AT n = averaging time for noncarcinogenic exposures
                              (exposure duration x  365  days/year);(days/years).
                        EF = exposure frequency (days/year) .
                        ED = exposure duration for  a child (years).
                     IRS c = intake rate for soil (mg/day).
                     RfD o = oral reference dose (mg/kg/day).
                        FC = factor to convert mg to kilograms.

Substituting the relevant exposure assumptions and toxicity dose-response values into equation
(3), the soil residential noncarcinogenic-based RBC for aluminum is calculated as follows:


         where:         THQ =0.1.
                        BW = 15 kg.
                      AT n = 6 years x 365 days/year or 2190 days.
                        EF = 350 days/year.
                        ED = 6 years.
                     IRS c = 200 mg/day.
                     RfD o=l mg/kg/day.
                        FC = 1,000,000 mg/kg.
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                                         SURFACE SOIL RBC (continued)

Industrial-Carcinogenic
The generalized formula for calculating a industrial-based RBC based on carcinogenic effects is
as follows:

        Where:
                        TR = target risk  (unitless).
                      BW a = adult body weight  (kg).
                      AT c = averaging time for carcinogenic exposures  (days per lifetime).
                        EF = exposure freguency (days/year).
                        ED = exposure duration  (years).
                        FC = soil conversion factor  (kg/mg).
                     CSF o = oral cancer slope factor [(mg/kg/day) -1].
                     IRS a = adult intake rate for soil   (mg/day).
                        FS = fraction of contaminated soil ingested.

Substituting the relevant exposure assumptions and toxicity dose-response values into eguation
the industrial soil carcinogenic-based RBC for arsenic is calculated as follows:

         where:         TR = 1E-06.
                      BW a = 70 kg.
                      AT c = 25550 days/lifetime.
                        EF = 250 days/year.
                        ED = 25 yrs.
                        FC = 1,000,000 mg/kg.
                     CSF o = oral cancer slope factor [(mg/kg/day) -1]
                     IRS a = 100  (mg/day).
                        FS = 0.5.
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                                         SURFACE SOIL RBC (continued)

Industrial-Noncarcinogenic
The generalized formula for calculating industrial soil RBCs based on noncarcinogenic effects is
as follows:

        where:       RBC a = noncarcinogenic risk-based concentration  (mg/kg).
                       THQ = target hazard guotient  (0.1).
                      BW a = body weight of an adult  (kg).
                      AT n = averaging time for noncarcinogenic exposures  (exposure duration x
                                 365 days/year);(days/years).
                        EF = exposure freguency (days/year).
                        ED = exposure duration for an adult  (years).
                     IRS a = intake rate for soil  (mg/day).
                     RfD o = oral reference dose  (mg/kg/day).
                        FS = fraction of contaminated soil ingested.
                        FC = factor to convert mg to kilograms.

Substituting the relevant exposure assumptions and toxicity dose-response values into eguation,
the soil industrial noncarcinogenic-based RBC for aluminum is calculated as follows:


        where:         THQ =0.1.
                      BW a = 70 kg.
                      AT n = 25 years x 365 days/year or 9,125 day.
                        EF = 250 days.
                        ED = 25 years.
                     IRS a = 100 mg/day.
                     RfD o=l mg/kg/day.
                        FS = 0.5.
                        FC = 1,000,000 mg/kg.
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                                              SUBSURFACE  SOIL RBC

EPA Region 4 has not prescribed default exposure factors for a construction worker scenario,
however, they do recommend that this scenario be addressed if there are any plans in the future
for a site to be excavated, and thus, could expose a future worker to subsurface soils.  EPA
Region-wide RAGS Supplements (EPA, 1991) suggests that a soil ingestion rate of 480 mg/day be
used for construction scenarios, however, the guidance does not prescribe exposure durations nor
freguencies due to that fact that the work is "usually short-term and is ... dictated by the
weather.  Thus, exposure freguency would generally be less than one year and exposure duration
would vary according to site-specific construction/maintenance plans. "(EPA, 1991).

Construction Worker-Carcinogenic
Based on the available EPA guidance, the generalized formula for calculating construction soil
RBCs based on carcinogenic effects is as follows:


        Where:

                        TR = target risk  (unitless).
                      BW a = adult body weight  (kg).
                      AT c = averaging time for carcinogenic exposures  (days per lifetime).
                        EF = exposure freguency (days/year).
                        ED = exposure duration  (years).
                        FC = soil conversion factor  (kg/mg).
                     CSF o = oral cancer slope factor [(mg/kg/day) -1].
                     IRS a = adult intake rate for soil   (mg/day).

Substituting the relevant exposure assumptions and toxicity dose-response values into eguation
the industrial soil carcinogenic-based RBC for arsenic is calculated as follows:

        where:          TR = 1E-06.
                      BW a = 70 kg.
                      AT c = 25550 days/lifetime.
                        EF = 250 days/year.
                        ED = 0.25 yrs.
                        FC = 1,000,000 mg/kg.
                     CSF o = oral cancer slope factor [(mg/kg/day) -1].
                     IRS a = 480 mg/day.
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                                        SUBSURFACE  SOIL RBC  (continued)

Cons truction Worker-Noncarcinogenic
The generalized formula for calculating construction soil RBCs based on noncarcinogenic effects
is as follows:

        where:       RBC s = noncarcinogenic risk-based concentration  (mg/kg).
                       THQ = target hazard guotient  (0.1).
                      BW a = body weight of an adult  (kg).
                       AT n = averaging time for noncarcinogenic exposures (exposure
                                 duration x  365  days/year);(days/year).
                        EF = exposure freguency  (days/year).
                        ED = exposure duration for an adult  (years).
                     IRS a = intake rate for soil  (mg/day).
                     RfD o = oral reference dose  (mg/kg/day).
                        FC = factor to convert mg to kilograms.
Cons truction Worker-Noncarcinogenic
Because none of the noncarcinogenic chemicals in subsurface soil exceeded a
noncarcinogenic-based RBC, a cumulative HI for this scenario was not evaluated at any of the
three study sites.
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                                                 Appendix B-2
                                          Exclusion of Inhalation and
                                   Dermal Exposure Pathways as Insignificant
                         Demonstration that the Inhalation and Dermal Exposure Pathway
                                   Associated with Arsenic is Insignificant

To demonstrate that the inhalation and dermal exposure routes contribute insignificantly  to
cumulative soil risks, an RBC was developed considering all three routes of  exposure  and
compared to the RBC based solely on the oral route of exposure. The  formula  for  calculating  a
RBC for all three routes of exposure is presented below:

Where:        TR = target risk  (1 x 10-6) .
              BW = body weight  (70 kg) (EPA, 1995a) .
         AT care = averaging time for carcinogenic exposures  (70 yrs x 365 days/yr=25,550  days).
              EF = exposure freguency  (250 days/yr)(EPA, 1995a).
              ED = exposure duration  (0.25 yrs)(site-specific assumption that
                   construction/excavation lasts 3 months).
              CF = soil conversion factor  (1 x  10 -6 kg/mg).
            CSFo = oral cancer  slope factor [(1.5 mg/kg/day) -1](EPA, 1996)
            CSFd = dermal cancer slope factor  [CSFo/gastrointestinal absorption  of  95% =
                   (1.6 mg/kg/day) -1].
            CSFi = inhalation cancer slope factor  [(15 mg/kg/day) -1](EPA, 1996)
            IRso = intake rate  for soil  (480 mg/day) (EPA,  1991a) .
              SA = skin surface area available  for soil contact; 50th percentile for
                   forearms and hands for an adult male  (2,300  cm 2) (EPA, 1990) .
              AF = soil-to-skin adherence factor  (1.0 mg/cm 2)(EPA, 1995a).
             ABS = chemical-specific absorption factor  (unitless).
             IRa = inhalation rate  (0.83 m 3/hr)(EPA, 1990).
              ET = exposure time  (8 hrs/day) (EPA, 1990)
             PEF = particulate  emission factor  (4.63 x 10  9 m 3/kg) (EPA, 1991b) .

Based on a three month exposure duration  (0.25  yr) and an  8 hour workday whereby a  worker  is  in
contact with soil orally, dermally, and via inhalation, a  1 x 10 -6 risk-based level  of 39.7
mg/kg for arsenic was calculated.  The carcinogenic RBC calculated based only on oral exposure
is using the same formula above but deleting the dermal and inhalation exposure  pathway and the
oral carcinogenic-based RBC for a construction  worker remains at 39.7 mg/kg  as shown  below:

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                                                 Appendix B-3

                                              TOXICITY ASSESSMENT

        The toxicity assessment section of an RA weighs the available evidence regarding the potential
for a particular chemical to cause adverse effects in exposed individuals, and provides an
estimate of the extent of exposure and possible severity of adverse effects.  The assessments
used to develop toxicity values consist of two steps: (1) hazard identification, and  (2)
dose-response assessment.  The hazard identification determines the potential adverse effects
associated with exposure to a chemical along with the types of potential health effects
involved.  In the dose-response assessment, quantitation of the toxicity values and estimation
of reference dose values are performed.

The COPCs at the site are well studied, toxicological assessments and technical criteria
documents prepared by EPA served as the primary information sources on pharmacokinetics, and
human health effects.  Toxicity factors [reference doses (RfDs))  presented in this section
reflect the most current toxicological information available from EPA (IRIS, 1996; EPA, 1995a,
EPA, 1995b) and other sources.  These factors are used in conjunction with default exposure
factors to develop health-based screening levels for evaluating risk.

An reference dose (RfD)  is an estimate (with uncertainty spanning approximately an order of
magnitude)  of a daily exposure to the human population (including sensitive subgroups) that is
likely to be without an appreciable risk of deleterious effects if experienced continuously
during a lifetime and is the toxicity value most often used to evaluate the noncarcinogenic
impacts from exposure to chemicals.  RfDs are specific to the route of exposure (i.e., an
inhalation RfD is used for inhalation exposure), critical effect (developmental or systemic),
and the length of exposure evaluated.  Chronic RfDs are specifically developed to be protective
against long-term exposure to a chemical.   Subchronic RfDs are developed to characterize
potential noncarcinogenic effects associated with shorter-term exposures.  The derivation
procedure for an RfD can be found in RAGS, Part A (EPA,  1989b) or other technical guidance
documents for criteria development.

A CSF and the accompanying WoE determination are the toxicity data most commonly used to
evaluate potential human carcinogenic risks.  The methods used by EPA to derive CSFs or unit
risks are described in RAGS, Part A  (EPA,  1989b).  For carcinogens, EPA usually assumes a
non-threshold response,  or that at every dose level of a carcinogen there is some amount of
adverse response; no dose is believed to be risk-free.   For carcinogens, EPA uses a 2-part
evaluation; determination of a WoE classification and calculation of a CSF.

Generally,  a CSF is a plausible upperbound estimate of the probability of a response per unit
intake of a chemical over a lifetime. Toxicity to carcinogens can be expressed in several ways.
The CSF is usually the 95 percent upper confidence limit (UCL 95) of the slope of the
dose-response curve and is expressed as (mg/kg/day)  -1.   Toxicity values for carcinogenic
effects can also be expressed as risk per unit concentration of the substance in the medium of
exposure, referred to as unit risks.

Site COPC exposure levels are not at high enough levels to warrant an acute or a subchronic
toxicity evaluation.  Chronic exposures are evaluated.   A list of all the criteria used for the
relative risk calculations is included in Table 6-1.  The RfDs and CSFs presented in this table
are the values provided in IRIS (1996), HEAST (EPA,  1995a)  and other sources, and have been
rounded to two significant figures.
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                                                  APPENDIX B

                                                  REFERENCES

EPA, 1990. Memorandum from Elmer W. Akin, Health Assessment Officer to PRPs and Risk Assessors.
Subject:  exposure default values at the Peak/Reeves/Bay Drum NPL Site. May 7, 1990. Atlanta,
Georgia.

EPA, 1991a. Risk Assessment Guidance for Superfund. Volume I:  Human Health Evaluation Manual
Supplemental Guidance "Standard Default Exposure Factors." Interim Final. Office of Emergency
and Remedial Response,  Washington, D.C.

EPA, 1991b. Risk Assessment Guidance for Superfund. Volume I:  Human Health Evaluation Manual
(Part B, Development of Risk-based Preliminary Remediation Goals. Interim. Office of Emergency
and Remedial Response,  Washington, D.C.

EPA, 1995. Supplemental Guidance to RAGS:  Region 4 Bulletins. Human Health Risk Assessment.
Interim.  November 1995. Office of Health Assessment, Waste Management Division, Atlanta,
Georgia.

EPA, 1997. Risk-Based Concentration Table, March 17, 1997. EPA Region III, Philadelphia, PA.
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