REPC&T DOCUMENTATION '• REPORT NO. ; 2.
2/£K PAGE EPA/ROD/R10-88/016 !
4. Tittt. »«d Subtitle
SUPERFUND RECORD OF DECISION
Commencement Bay/Tacoma, WA
^Yirst Remedial Action - Final
J Authors)
9. Performing Organization Name and Address

12. Sponsoring Organization Nam* and Address
U.S. Environmental Protection Agency
401 M 'street," S.W.
Washington, D.C. 20460
3. Recipient's Accession No.
5. Report Oat*
03/31/88
6.
8. Performing Organization Rept. No
10. Project/Tasl ,
    The  Commencement Bay/Tacoma siteTis a  190-acre  industrial/municipal  landfill located
  in  Pierce County,. 'TaconaV Washington.  The  landfill  is'operated by  the City of Tacoma
  Refuse Utility and is  surrounded primarily  by  residential development  and open'land,
  with  some commercial and  industrial development.   Several utilities  (i.e., sewer, water,
  and storm) pass through  the site.  An aquifer  beneath the site  provides drinking water
  to  the Town of Fircrest  and the city of  Tacoma, both  of which have  wells near the
  landfill.  The aquifer  is also used by private  individuals for  their  domestic water
   upply.  Ground water'  flows predominatly  to the southwest toward  Leach Creek, which lies
  approximately 0.25 mile  west of the landfill.   consequently, wetlands  downstream of the
  landfill could potentially be exposed to  contaminants in the surface  water and ground
  water.  The Tacoma landfill began operations  in  1960, receiving only  nonhazardous wastes
  including assorted municipal and industrial wastes,  construction  and  demolition wastes,
  and bulk waste.  To  date, about 4 million  tons  of refuse have been  deposited at the
  landfill to depths of  20  to 80 feet.  Although  the landfill does  not  accept hazardous
  wastes for disposal,  it  did receive wastes  in  the 1960s and 1970s  that have since been
  designated as hazardous  substances.  In  1983,  investigations by  EPA revealed the
  presence of hazardous  compounds in the ground  water  and soil near  the landfill.
  (See Attached Sheet)
                  i°6'nc'1ptor*
  Commencement  Bay/Tacoma,  WA
  First Remedial  Action  - Final
  Contaminated  Media:   sw,  soil
  Key contaminants:   VOCs (benzene,
   ti. Id*ntlfi*rs/Op*n-End*d Terms
toluene, xylenes),  metals (chromium)
   c. COSATI Field/Group
   Availability Statement
                   19. Security Class (This Report)
                      None
                   20. Security Class (This Page)
                      None
21. No. of Pages
   121
                                                                                  22. Price
(See ANSI-Z39.18)
                                        See Instructions on Reverse
                                            OPTIONAL FORM 272 (4-77)
                                            (Formerly NTIS-35)
                                            Department of Commerce

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 (PA/ROD/R10-88/016
 ommencement Bay/Tacoma, WA
 irst Remedial Action - Final

16.   ABSTRACT (continued)

Subsequent investigations indicated that the ground water is contaminated with VOCs.  In
response, the City of Tacoma connected affected residences to the public water system.
In 1986, accumulation of landfill gas in a utility vault adjacent to the landfill
resulted in a minor explosion.  A field survey was initiated to evaluate the extent of
offsite gas migration, and based on this survey a gas extraction system was constructed
to extract, collect, and combust the gas.   Gas samples collected at the landfill
revealed high levels of VOCs.  The primary contaminants affecting the ground water and
surface water are VOCs including benzene,  toluene, and xylenes.

  The selected remedial action for this site includes:  construction of a cap on the
landfill with runoff directed to appropriate storm or sanitary sewers,  and installation
of a gas extraction system and gas probes  to monitor methane gas production;
installation of a ground water pump and treatment system with discharge of treated water
to a local creek or the POTW and alternate water supply if needed;  and ground water and
surface water monitoring.  The estimated present worth cost for this remedial action is
between $21,015,000 and $23,418,000.  The  estimated O&M costs were  not provided.

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                   REGION 10
               1200 SIXTH AVENUE
              SEATTLE, WASHINGTON
              RECORD OF DECISION,
             DECISION SUMMARY, AND
            RESPONSIVENESS SUMMARY
                      FOR

             FINAL REMEDIAL ACTION
  COMMENCEMENT BAY - SOUTH TACOMA CHANNEL
             TACOMA LANDFILL SITE
             TACOMA, WASHINGTON
                  MARCH 1988

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            RECORD OF DECISION
      REMEDIAL ALTERNATIVE SELECTION
           FINAL REMEDIAL ACTION
COMMENCEMENT BAY - SOUTH TACOMA CHANNEL
             TACOMA LANDFILL
           TACOMA, WASHINGTON

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                                RECORD OF DECISION
                          REMEDIAL ALTERNATIVE SELECTION
Site
      Commencement  Bay -  South Tacoma Channel,  Tacoma  Landfill  site - Tacoma,
Pierce County,  Washington.

    i
Purpose
      This decision document presents the selected final  remedial  action  for
the site, developed  In accordance with the Comprehensive  Environmental
Response, Compensation,  and Liability Act of 1980 (CERCLA).  as  amended by the
Superfund Amendments and Reauthorlzatlon Act of 1986  (SARA), and  consistent
with  (where not precluded by SARA) the National Contingency  Plan  (NCP, 40 CFR
Part  300).  The State of Washington, In close consultation with EPA, has
developed and concurred with the selected remedy.   A  copy of the  state
concurrence letter Is attached as Appendix 0.


Basis for Decision
     The decision Is based upon  the administrative record for the  site, as
obtained from the files of the Washington State Department of Ecology and  the
U.S. Environmental  Protection  Agency (EPA).   This  record Includes, but Is  not
limited to.  the following documents:


     o    Remedial  Investigation Report for  the Tacoma Landfill, Tacoma,
          Washington (December 1987)

            •                       •*
     o    Feasibility Study of the Tacoma Landfill Site, Final  Report
          (December 1987)

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     o    Decision Summary of Remedial Alternative Selection

     o    Responsiveness Summary (attached as Appendix 8)

     o    Staff summaries and documents—An Index (Appendix C) Identifies
          other Items which are Included In this administrative record.

Description

     This record of decision (ROD) addresses source control of on-slte
contaminants through capping of the landfill and extraction of methane gas.
                                            \^
Management of migration for off-site contaminants will be through a
groundwater extraction and treatment system.

     The remedial action Is designed to:

     o    reduce the production of leachate by placing constraints on further
          site operations and by capping the landfill.

     o    eliminate off-site gas migration through the gas extraction system.

     o    prevent further migration of the contaminated plume via the
          groundwater extraction-treatment system.

     o    further protect public health and the environment via monitoring of
          groundwater, surface water, gas probes, and air emissions.

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      o    provide  an  alternate water supply (Tacoma municipal  water) to any
           residents deprived  of their domestic  supply due to demonstrated
           contamination  from  the landfill  or  due  to the  action of the
           extraction-treatment system.

      Treatment will be sufficient  to reduce contaminant  levels in  the
groundwater to or  below  cleanup  standards.  Performance  levels for the
Identified contaminants  of concern are presented  in  Table 8.   The methodology
to be  used to develop performance  levels for  the other contaminants  in  the
groundwater Is discussed  in the  Selected Remedial Alternative  section of  the
ROD.   Treatment should be permanent,  and should effectively reduce the
toxldty and mobility of  the  contaminants.  Performance  levels  are not  to be
exceeded during the operational  life of the remedial action.   Treated water
discharge shall  at all times  be  consistent with federal  laws and Washington
State  laws.  Any treatment system which will produce air emissions will  be
designed to meet appropriate  federal  and state Air Toxics Guidelines and to
use Best Available Control Technology (BACT) on the effluent air stream.

     Containment of the plume will  be confirmed by Installation and periodic
sampling of monitoring wells as well  as continued, scheduled monitoring  of
private and public wells.  Extraction will  continue until water quality  at the
compliance boundary (defined by WAC 173-304 as the edge of the  filled area)
consistently meets or  exceeds  drinking water standards, or previously
established and  approved  health-based criteria.   In addition to meeting
health-based criteria, potential Impacts  to public and private  water supplies,
and to Leach Creek must be considered In  the decision to shut off the system.

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     Those residents who are deprived of domestic drinking water, either
because their wells water quality shows demonstrated contamination from the
landfill or because the quantity available has been reduced by the action of
the extraction-treatment system, will be connected to city water supplies.

     Source control measures are expected to reduce contaminant concentrations
In the groundwater system.  Source control measures consist of constructing a
cap on the landfill and appropriate regradlng to minimize Infiltration and
maximize run-off, ultimately reducing leachate volume and toxlclty.  Unllned
areas of the landfill will be capped as soon as possible.  WAC 173-304 defines
the minimum requirements for a cap on a municipal landfill.  A more stringent
                                            \^
cap will be required unless further analysis of the cap, to be provided during
remedial design, shows that a significant reduction In leachate volume or
toxlclty would not be achieved.

     Increased run-off due to the construction of the cap will be routed off
the landfill to reduce Infiltration.  The run-off collected from the landfill
will be directed to the appropriate storm or sanitary sewers, consistent with
local storm drainage ordinances or pre-treatment regulations.  The storm
drainage plan, prepared as part of the remedial design, will determine and
minimize any Impacts on downstream Increases In peak. flow.

     The city of Tacoma (Tacoma) will Implement a closure plan for the
landfill consistent with Washington State Minimum Functional Standards for
Landfill Closure (WAC 173-304). and as appropriate, Washington State Dangerous
Waste Regulations (WAC 143-303).

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     Institutional controls will be Implemented, consistent with the final
design, to assure that the remedial action will continue to protect health and
the environment.  Tacoma, In cooperation with the town of Flrcrest and Pierce
County, will pursue the establishment of an ordinance, or other suitable
methodology, to restrict drilling of water supply wells In an  area from Tyler
Street to Leach Creek, and from Center Street to approximately South  56th
Street.

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Declaration

     Consistent with CERCLA, as amended by SARA, and the NCP, It 1s determined
that the selected remedy as described above Is protective of human health and
the environment, attains Federal and State requirements which are applicable
or relevant and appropriate, and Is cost-effective.  This remedy satisfies the
preference expressed In SARA for treatment that reduces toxlclty, mobility, or
volume.  Finally, It Is determined that this remedy utilizes permanent
solutions and alternative  treatment technologies to the maximum extent
practicable.
Date                                         Regional Admlniswaror
                                             Environmental Protection Agency
                                             EPA - Region 10

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       DECISION SUMMARY
REMEDIAL ALTERNATIVE SELECTION
     FINAL REMEDIAL ACTION
       TACOMA LANDFILL
     TACOMA, WASHINGTON

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                            TABLE OF CONTENTS
                                                                  Page


 I          SITE  DESCRIPTION AND LOCATION                           i


 II         SITE  HISTORY                      .                      3

           A.  Landfill History and Operations                         3
           B.  Regulatory History - Previous Investigations              4
           C.  The Remedial Investigation/Feasibility Study             5


 III        SITE  ENVIRONMENT                                       s


 IV         NATURE  AND EXTENT OF  PROBLEM                            9

           A.  Extent of Gas Migration     -.                           9
           B.  Contaminants Detected                               13
           C.  Extent of Groundwater Contamination                  14
           D.  Surface Water                                       16
           E.  Future Impacts                                      17
           F. The Endangerment Assessment                          19


V         ALTERNATIVES EVALUATION - FEASIBILITY STUDY            27


VI        SELECTED REMEDIAL ALTERNATIVE                          as

          A.  Description of the Selected Remedy                     35
          B. Statutory Determinations                              43


VII       ENFORCEMENT                                            49


VIII      COMMUNITY RELATIONS                                    so




APPENDICES

     A.   APPLICABLE AND APPROPRIATE REQUIREMENTS

     B.   RESPONSIVENESS SUMMARY

     C,   INDEX TO ADMINISTRATIVE RECORD

     D.   STATE CONCURRENCE LETTER
                                  11

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LIST OF TABLES

Table 1
Table 2
Table 3
Table 4
Table 5
TableS
Table?
TableS

Figure 1
Figure 2
Figured
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11

Summary of Organic Compounds Detected in Landfill Gas
Threshold Limit Values for Landfill Gas Components
Organic Waste Components Detected at the Landfill
Metals Detected at the Landfill
Travel Times to Reach Maximum and Threshold
Concentrations, Close-in and Distant Wells
Summary of Detailed Evaluation of
Remedial Alternatives
Section 121(bXlXA-G) Evaluation Factors
Performance Standards for Treatment System/Discharge
to Surface Water
LIST OF FIGURES
Site Location
Site Vicinity
T-andfili Zoning
Leach Creek Drainage Basin
t-ar*^ii Site Cross Section and Lithology
Location of Private Wells/Extent of Contamination
Landfill Drainage Patterns
Landfill Gas Extraction System
Contaminant Distribution in Groundwater
Contaminant Distribution in Groundwater (continued)
Current and Predicted Contamination
following
Page
11
12
14
14
24
32
32
37

1
1
1
6
7
8
8
9
15
15
18
     111

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 I.   SITE DESCRIPTION AND LOCATION

     The  Tacoma Landfill,  operated  by  the  City of Tacoma  Refuse  Utility,  Is
 located  In  Sections  12  and  13 of Township 20  North,  Range  2  East,  Pierce
 County.  Washington.   The  landfill  covers  190  acres  and Is  bounded
 approximately  by  South  31st Street on the north.  Tyler Street on the east,
 South  48th  Street on  the  south, and Orchard Street on the  west.  Figures  1,  2
                                              •
 and  3  Illustrate  the  location of the  landfill,  the vicinity  surrounding the
 landfill, and  the site  itself.  The landfill  serves  a population of
 approximately  212,000.  To date, approximately  4.0 million tons of refuse  have
 been deposited  at the landfill since  It operted  In 1960.  Currently about 600
 tons per day of refuse are placed  In the  landfill.

     The  landfill does not accept hazardous wastes for disposal.  However,  the
 landfill received wastes  In the 1960s and  1970s that have since been
 designated as hazardous substances  under State and Federal  law.

     Figure 2 shows the general topography of the landfill and surrounding
 area.  Orumllns (low, long ridges)  abound  In the general  area and display a
 north-south axial  configuration.   Solid  waste has been disposed of at the site
 between five drumllns.  The landfill's western boundary Is  approximately one
 quarter mile from Leach Creek, but  the landfill does not  lie  In the flood
 plain of that creek.   The landfill  Is surrounded primarily  by residential
 development and open  land, with some  commercial and industrial  development.
 Land use for the area surrounding the landfill 1s shown on  Figure 3.   No use
of natural resources  other than groundwater 1s noted on land  use Inventories.
           -#
 Several utilities  (sewer, water,  and  storm) pass through  the  site.

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                                                   STATE OF WASHINGTON
0124          3

   SCALE : I* =  4  MILES
FIGURE I
SITE LOCATION M*

TACOMA LANDFILL ^

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             r, T-.-'l -_P1 ivKUlg _H~*. i- • *w
             } -• -:^-T '"%-."•>• VjHTt '.'•  -

             S^'^f'iSi
                        l-.~5\\ iL\^JnTTFTR^

i ..-•• p.jVl^* r:e-; f J-YrV^  V,  li"; . l-'MQlJi,

g*SWf?/4-l
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                                 f^l    ^''T^tQMA.rTiff^T/-?]
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                                ^>)- -*" :  !^LTAcdwAC>S7::' :i
                                '••"/ l    hy-inNo: WA--^^
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                                t // {    MIB^' *-:--.i,i»*
                                I- . !    t'ilnJAGOMA-l-l-iy^l
                                                 .r
                                           lE^ I' HK;'
                COU«SE ' Map&og.j JKH J^
2000' 1000' 0
              2000'
4000
FIGURE 2

SITE VICINITY

PRODUCTION WELL LOCATIONS

• TACOMA LANDFILL RI/FS

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                                 TACOMA
                                LANDFILL
   LEGEND
   COMMERCIAL
   INDUSTRIAL
   RESIOENTAL
 JOOO 2000
SCALE  l-* 2000'
4000
                                 FIGURE 3
                                 LANDFILL  ZONING.*'
                                 TACOMA LANDFILL

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    Apartments, undeveloped land, and commercial properties including a

bowling alley, offices, building supply and paint stores, and gas stations are

located north of the landfill.  Immediately east of the landfill are apartment

complexes, single family residences, and undeveloped land.   The area further

east between Tyler Street and South Taccma Hay Is occupied  by the Burlington

Northern Railroad, Industrial/commercial development,  and an open area known

as the South Tacoma Swamp.  Between the west edge of the landfill and Orchard

Street there are several apartment buildings and commercial  establishments.

West of Orchard Street and south of the landfill  there is residential

development and undeveloped land.

                                            \
    The landfill lies In the central portion of the Tacoma/Flrcrest  upland

ground water system.  A significant area for the central upland In  the

vicinity of the landfill Is Leach Creek.

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 II.   SITE HISTORY

      A. Landfill History and Operations

      The  Tacoma Landfill  began  operations  in  1960, and  now  serves  a  population
 of approximately  212.000.   The  wastes  received and disposed  at  the landfill
 Include garbage,  rubbish,  industrial wastes,  construction and demolition
 wastes, street  refuse,  litter,  and bulky waste.  To date, approximately 4.0
 million tons of refuse  have  been deposited at the landfill.  Filled  areas vary
 from  20 to  80 feet  deep.  Currently some 600  tons per day of refuse  are placed
 In the  landfill.

      Most of the  site has already been filled.  The next section of  the site
 to be filled Is called the Central Area Pit.  This section of the landfill
 covers  approximately 18 acres and was developed during the summer and fall of
 1987.   A flexible membrane liner and leachate collection system were Installed
 In the  Central Area Pit.  The liner and leachate collection system were
 designed primarily  to maximize volume for waste disposal.  To date,  there has
 been  no documentation received on the integrity of the liner.

      Day to day operations of the landfill  are regulated by the  Tacoma-Plerce
County  Health Department (TPCHD) with oversight by the Washington Department
of Ecology (Ecology); the operating permit Is Issued  annually by TPCHD.

     At the current rate, the 190-acre site has  a remaining life expectancy of
approximately four to five years if all the solid waste material is disposed
without a significant reduction In volume.   Tacoma has indicated it  Intends to
 Implement programs to extend the life expectancy of the landfill.

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     There are many large and small  Industries  in  the  Tacoma/Plerce County
area which have disposed of wastes at  the  landfill.  Memoranda reviewed during
the preparation of the Description of  Current Situation report and the RI
indicate that some hazardous wastes  were disposed  of at the landfill.
Investigations concerning the volumes,  the  chemical composition of the wastes,
and the disposal locations are ongoing.
     B. Regulatory History - Previous Investigations

     In 1983 EPA conducted an  investigation and detected hazardous compounds
                                            X
In samples of ground water and  soils near  the  landfill.  This led EPA to
Include the landfill on  the National Priorities List of hazardous waste sites
as part of the South Tacoma Channel site.  Through a cooperative agreement
with EPA, Ecology began  an Investigation  Into- contamination at the site In
1984.  On June 27.  1986,  Tacoma assumed responsibility for conducting the
remedial Investigation and feasibility study  under a Response Order on Consent
Issued by Ecology.

     Since 1983 testing  has been conducted at  and around the Tacoma Landfill
by EPA, Ecology. TPCHD,  Tacoma, and others.   The testing revealed that three
private wells contained  contaminants.  The priority pollutant volatile organic
compounds which were detected  In the ground water samples were primarily
chlorinated organics.  Twenty-four volatile organic compounds were found In
groundwater contaminated by the landfill.

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      Because of the concern about the public health effects of the
 contaminants,  particularly vinyl  chloride,  the  TPCHD recommended that Tacoma
 connect  these  affected residences to  the  Taccma public  water system.   As a
 precautionary  measure.  Tacoma  also connected two additional  residences whose
 wells were  near the area.   Monitoring continues  quarterly  to ensure the clean
 water supply for potentially affected residents  while appropriate  cleanup
 actions  are  approved and  carried  out.
     C. The Remedial Investigation/Feasibility Study (RI/FS)

     The remedial  investigation (RI), conducted by Tacoma1s consultant.  Slack
and Veatch. was performed  in two phases.  Phase 1  activities (July  1986
through January 1987) consisted primarily of field Investigations to
characterize both  the hydrogeology of the site and tfre contaminants present  In
the various media  at and surrounding the site.  Phase 2, conducted  from
January through November 1987. was designed to fill  in data gaps Identified  at
the conclusion of  Phase 1 and to provide the data  necessary for the
endangerment assessment and the feasibility study  (FS).

     Upon completion of the RI and and evaluation  of the alternatives, the
City, through their consultants (Black and Veatch).  submitted a draft RI and
FS report In September and October 1987 for agency review and approval.  The
final RI/FS reports were published December 1987.   Public comment on the
studies was completed In March 1988.

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III.      SITE ENVMBIT
     The Tacoma Landfill site is located In the northern portion of the
Chambers/Clover Creek d-iinage basin (see Figure 4).  This area is part of the
Puget Sound lowland.  The study area is bounded by:  the Tacoma channel to the
east; Center Street to the north; 56th Street to the south; and Leach Creek to
the west.

     A moderate climate prevails.  Winter temperatures are seldom below
freezing and summer temperatures are rarely above 80*F.  Approximately
thirty-seven Inches of rain fall in a normaKyear.  Studies conducted In the
Puget Sound region have Indicated that approximately 301 of rainfall becomes
groundwater.

     The geology of the site consists of a series of glacial materials, mostly
sand and gravel laid down over older alluvial silts and sands.  The
stratlgraphlc units (layers) described In the Remedial Investigation (Black
and Veatch, 1987) from youngest to oldest (top down) are:

     A.   Vashon Till (dense gray, gravelly, sllty, sand) (Qvt)
     B.   Vashon Advance Outwash (sands/gravels) (Qva)
     C.   Colvos Sand (dense sand/some gravel) (Qc)
     0.   Older Gravel (dense sandy gravel) (Qog)
     E.   Older Till (dense sllty, gravelly sand) (Qot)
     F.   Older Outwash (dense sllty. gravelly sand) (Qoa)
     G.   Older Sand (dense fine/medium sand) (Qos)
     H.   Older Lacustrine (lake bottom silts) (Qol/Qk)
     I.   Und1fferent1ated Quaternary Sediments (Qu)

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      SPRING
      FLOW-G
                             LEACH CREEK
                             DRAINAGE
                             HASINA
                                               FLETT CREEK
                                               DRAINAGE 3ASIN
             UMVERSIT
                                           \   r
                                       y-TACOMA
                                      / UANDFILL
                                          FIGURE ADAPTED FROM CLOVER/
                                          CHAMBERS CREEK <3£OHYOROUOG1C
                                          STUDY
SCALE IN MILES
FIGURE 4

LEACH CREEK DRAINAGE BASIN

TACOMA LANDFILL Ri/FS

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      The  affected aquifer is  located  between  the  lower  zones  of  the  Colvos
 Sand  and  the  Older Lacustrine.   The Older  Lacustrine  unit  serves  as  the
 regional  aqultard In  the  landfill  area. A  cross section  through  the  area
 (Figure 5)  shows  the  ridges,  valleys, and  the  lithology  (layers).

      Water,  Infiltrating  through the  landfill, picks  up  various contaminants.
 Where the Vashon  Till  Is  not  present  beneath the waste,  contaminants move with
 the water through the  unsaturated  zone and into the aquifer.  It  is also
 possible for  low  solubility,  pure  phase fluids, called dense, non-aqueous
 phase liquids  (DNAPLs). such  as chlorinated hydrocarbons to enter the
 aquifer.  Evidence of  this has not been shown, nor has It been disproven.  The
 water table lies  within the Colvos Sand unit, about 70 feet below the bottom
 of the landfill.

      The predominant flow direction of the water table aquifer Is
 southwesterly  toward Leach Creek.  However, during periods of heavy water use
 by Tacoma city wells (summer and early fall),  the  groundwater flow direction
 Is reversed.  Also, depending on local conditions, groundwater and contaminant
 movement may be downward or upward.

      The Older Alluvium reportedly forms  the  confining layer.   Leach  Creek Is
 the closest discharge point of the aquifer.  Additional  information from
 future activities will clarify the ground  water flow conditions  near  the creek
 and elsewhere around the site.

      The aquifer  Is part of the Chambers/Clover Creek Ground Water Management
Area.   The TPCHD  Is petitioning EPA for  a  Sole Source Aquifer designation for

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     5
        400 r
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       300
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                                                                                                                                                SOUTH

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                                                                          Mel Number



                                                                          WelLocaUon



                                                                          Water Table

                                                                          12/4/16



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Veilical E«agge«allon • 8
                                                                                                   OroundMaler Flo*
                                                                                                                                        sire CROSS setrriON ANII
                                                                                                                                        IJTIIOUMiV


                                                                                                                                        lACOUA

-------
 this  aquifer.   The  Town  of Fir-crest and the  City of  Taccma  both  operate  wells
 near  the  landfill  (see Figure  2).   In  addition,  the  aquifer  Is also  used  by
 private Individuals  for  domestic  water supply  (see Figure 6).

      Wetlands downstream of  the  landfill on  Chambers Creek could potentially
 be exposed  to contaminants  In  the  surface  water  and  ground water.  None of the
 five  endangered  species  identified  in  the  State  of Washington Is common to the
 area  surrounding the  landfill.

      The topographical lowpoint in  the  landfill  is currently at the north end
of the Central Area Pit.  Some runoff  from surrounding areas drains and
 discharges  to the sanitary sewer.   Drainage  from the north and along Mullen
Street Is directed towards a pond situated between the bowling alley parking
 lot and northern landfill property  on Mullen Street.   Drainage from the west
 side of the site Is directed toward a  catch  basin and discharges to the Leach
Creek retention basin.   The south end of the site drains to the south and is
not collected.  Drainage  patterns are  shown  in Figure 7.

-------
                                                                                         ,' 0. •' • I •' ,i  L .
                                                                                                               I (If Mill «NP !«•!>
                                                                                                                tfi no! cuMiMif UMO
                                                                                                                MIO •IHf MOI CCH1IMMO
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                                                                                                            . T  noun
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                                *i  *   /   /  .
                                _^ ,x^-2--_—^pv^ry^'1
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                                              -

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                                      i4»»tfii ^ M»».J*. v .....  -*. • TA-^*-> .....  -  ----

-------
        IMIIMl M«l> •!!•
        M
-------
IV.  MATURE AM)  EJtTHT OF

     A. Extent of Gas Migration

     In May 1986. accumulation of  landfill gas In a utljlty vault at the Town
Concrete Pipe Company (located Immediately adjacent to and west of the
landfill) resulted  In a  small explosion.  Tacoma had already hired a
consultant (Mandevllle Associates) to address problems of gas production and
migration at the landfill and was  able to Immediately Initiate a field survey
to evaluate the extent of gas migration off-site.  Based on this survey, the
consultant designed and  constructed a gas extraction system to extract,
collect and combust the  gas.  The  field survey showed the biggest problem to
be southwest of the site and  this  Initial effort concentrated on controlling
gas from migrating  Into  businesses In this area.

     The current landfill gas system consists of 128 extraction wells,
collection piping.  77 gas probe locations, and the motor blower/flare station
where contaminants  are Incinerated.  The system layout Is shown on Figure 8.

     Tacoma has conducted a two-stage gas monitoring program to monitor the
effectiveness of the extraction system.  Figure 8 shows the locations of 66
probes Installed around  the landfill.  Each of these probes consists of two
to five probes able to monitor gas at depths from 6 to 70 feet.  These probes
are checked twice a week and  seem  to Indicate that the shallower gas Is being
controlled by the extraction  system.

-------
        *l      lu  /
   }<    >   //,,..
»»'»-\t        f"
                                                                                                      UfiUfi
                                                                                                     O   Wt «tt
                                                                                                  KKJIIHK H
                                                                                                  I ANIIMI I. liA.S

-------
      The gas found deeper than about 35-40 feet is not being controlled as
 well.   As a result of this  information.  Tacoma is  installing approximately 74
 new,  deep extraction  wells  around the landfill.   This work began  on
 January 27, 1988.

      The City  has  also  been  conducting an  off-site monitoring  program
 beginning in May.  1986.   From  May 1986 until August 1987,  this  program  focused
 on  businesses  and  apartments to  the  south  and  west of the  site, where both
 ambient and point  source  measurements were  taken.   Beginning  in August  1987,
 the current off-site  monitoring  system began.  This  consists of monitoring
 utility vaults  In  residential  areas  (shown  on  Figure  8). and routine ambient
                                             \
 and point  source monitoring  in some  businesses and  vacant  apartments.   The
 data from  this  effort shows  that  methane Is still  escaping  the  landfill and
 finding Its  way to  the surface In off-site  locations.  The  utility vault data
 shows several areas, around the landfill to  be of particular concern.

     The Minimum Function Standards  require that the  concentrations In
off-site structures be below 100  parts per million  (ppm) by volume of
 hydrocarbon  In ambient air.   From November  1986 through October 1987, the
 readings of  ambient air In off-site  structures were below the limit;  however,
 some point  sources monitored such as foundation cracks and closed vaults on
occasion have shown readings above 100 ppm.  Readings above the limit were
found In the ambient air In  one building west of the  landfill near 40th
Street  (Classic Auto)  In November 1987.   The City  Installed four additional
gas extraction wells In this area In December 1987.   No readings were detected
 In the building after  the first well  was  connected to the system on
December 15, 1987.
                                       10

-------
      Ecology  has  requested that additional  gas  probes  be  placed  in  the
neighborhoods of  concern.   The  existing  probes  are  well within the  influence
of  the gas  extraction  wells and do  not represent ambient  conditions further
off-site.   Methane  concentrations  in  utility  vaults can also be misleading.
Gas concentrations  fluctuate a  great  deal with  changing atmospheric
conditions.   Therefore,  it is possible that landfill gas  could be found in a
house without observing  it in the vault.  Additional gas  probes are needed to
better determine  the performance of the  gas extraction system.

     A total of 42  landfill  gas  samples  were collected at 26 locations around
the landfill.  The  gas samples  collected from gas wells and probes were
analyzed for priority  pollutant  volatile organic compounds (VOC).  The
analytical results  are summarized in Table 1.   The methane concentration was
analyzed for five of the Phase  1 samples and was field measured for seven of
the Phase 2 samples.   These  results are presented below:
     Sample No.
Methane (ppm)
Sample No.
Methane (ppm)
     Phase 1
     GS-001
     GS-002
     GS-002DUP
     GS-003
     GS-004
540.000
430,000
430.000
560,000
240.000
Phase 2
GS-213
GS-214
GS-215
GS-218
GS-219
GS-220
GS-221

370.000
480.000
610,000
560,000
200.000
200,000
200,000
                                       11

-------
ORGANIC C
     OF ?1UO«i7T MLiJTAKT VOtATILI
         3C7XCTZD IS LjUTCm:. CAS SAK?'_£S
     Caac*ncracLanj La

04/23/14
04/23/M
04/23/14
04/U/M
04/23/M
04/23/M
04/23/M
04/23/M
04/23/M
04/23/M
04/23/M
04/23/M
00/24/M
01/24/M
11/13/M
12/09/14
12/09/14
02/12/17
02/10/17
02/10/«7
02/10/17
02/12/17
02/12/17
02/10/17
02/10/«7
02/10/17
02/10/17

2400
700
1200
24OO
2900
1100
laoo
1000
1100
1100
2000
4«00
13.30
2200
41OOJ
2100
1400
2400J
3400
• 40J
1200
2400
4100
2400
2600
2400
1200J
Qilora-
'.400
:30O
1230
940
930
1400
3COO
1130
1600
3000
1200
100
710
230
1000
130U
1000
1000U
300U
1COO
laoou
10000
IOOOO
10000
IOOOO
IOOOO
1000U
Qiian-
• t--.«n«
1.00
IOOOO
300
2300
2300
13000
4100
13000
1300O
T»
n
1400
33.30
430
2300J
9100
1000
2000U
12000
2000
IMOJ
1200
2200
1300J
1400J
20000
2000O
i.l-Ol-
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900
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1700
13. JO
1400
3 IOOJ
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100 OU
14001
IOOOO
400J
13001
1300
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1300
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1.2-01
ehlar*-
3000
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1230
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1230
3000
3000
3000
3000
T*
3000
12000
33.30
230
1000
1600
1300
1000U
3000
IOOOO
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10000
1900
IOOOO
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IOOOO
IOOOO
1,1-01-
chlor*-
3000 '
j oca
1230
1230
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17000
3000
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TB
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T*
13.30
43
1000
100
100
IOOOO
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320J
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 CBCAMIC
          TAIU  1  (cone)
      or PUOUTT  nujrum VQLATIU
CCKFOOfDS OC7ZC7IB 19 LjUTCf Oi. CAS SAMFU3
      Cane ant rat Jam  La u«/mj
                                       1.1.1-
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CW-O1
9-21
9-43
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9-230
9-231
9-069
9-04*.
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9-13
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-------
      The landfill gas contains significant concentrations  of VCCs  and has been
 proposed as a possible migration pathway for these compounds to  the
 groundwater,  particularly when groundwater contamination  is  found  upgradient.

      The American Congress of Governmental  Industrial  Hyglenists has  Issued
 threshold limit values (TLVs) on airborne concentrations of  various
 substances.   These limits are intended as guidelines  in the  control of
 potential  health  hazards.  The time-weighted  average  (TWA) TLV concentration
 for a normal  8-hour  workday and  a 40-hour workweek  is  the concentration which
 nearly all  workers might  be exposed  to without adverse  effect.  The  compounds
 detected  In  landfill  gas  samples  that  exceeded 15 percent of the TWA  values
 are given  In  Table 2.   Two of the TWA's  were  exceeded  (toluene and vinyl
 chloride).  The detected  concentrations  listed In Tables 1 and 2 are  from
 samples  collected  Inside  the  respective  gas well  or probe and are not
 representative of  ambient air concentrations.

     EPA's  ISCST  (Industrial  Source Complex Short-Term) dispersion model was
 used to.  predict the  potential  landfill air quality Impacts.  Toluene was
 generally detected at  higher  concentrations than  other VOCs In the landfill
 gas samples and had  the highest mass flow rate both in and out of the flares
during the flare test;  therefore,  it was  selected as the pollutant to be
assessed by the air  quality analysis.

     The worst case  analysis  predicted the highest toluene concentration
 (using a one hour  averaging time)  to be  slightly  greater than 2 ppb.   The
Draft New Source Guidelines for Toxic Air Contaminants (Sept. 1986) for the
State of Washington  indicate  a 14  ppb  toluene to  be the acceptable ambient
                                       12

-------
                                                         TAflLE  2

                                    T31IS3CCJ L2CT VAL3C3 ro
                                                                       CAS CCHPOUXOS
              (CAS

        (71-4J-2)
         oro«
    (73-1S-4)
    «-1.2-0le
    (3*0-3»-0)
    (75-Of-2)
      Oxlorlda (73-01-*)
2-Baunoo* (391-7t-4)
Tot«i XjLmamt (1330-20-7)
1.2-OteAiaroachjLfM  (107-04-2)

S*BDl. So.
3S-012. SS-217
Oi-007
5S-012
SS-011
33-007
SS-010
SS-217
33-011
1S-011
CS-012
"• ir—~*
3«e*et»d
u«/«I
4. tOO
17.300
120. 000
77.000 (2)
73.000
lao.ooo
124.000
1.200
170.000
12.300

7P"
19
3
200
:oo
130
100
3
3
100
10

u«/»3
30.300
:0.35C
790.300
433. 30C
330.300
373.300
10.000
20 . 300
433.300
40.000
       lua of 160.000
                       Awcac*. )Uf«c«nc« 34.
                                         for
                                         d In
                                                          Ln
                                                                   CS-217i

-------
 level;  therefore,  it would  appear  that as  long as the current gas collection
 system  remains  functional,  ambient air concentrations of VCCs should remain
 well below  ambient air standards.

     B. Contaminants Detected

     Groundwater,  surface water, leachate. sanitary sewer,  subsurface  soil,
 sediment and  landfill  gas samples were collected during  the RI  sampling
program.  The prevalent  contaminants detected during the sampling program were
volatile organic compounds  followed by semi volatile  organic compounds  and
metals.

     Twenty-four volatile organic chemicals were found in the groundwater.   Of
the twenty-four chemicals,  the following  seven Indicator chemicals  were
 Identified  In the  Endangerment Assessment in the RI  as being of most concern
because of  their toxlclty,  frequency of occurrence,  and  primary targets (human
population):

     o    vinyl chloride
     o    benzene
     o    1,2-dlchloroethane
     o    methylene  chloride
     o    1,1-dlchloroethane
     o    chloroethane
     o    toluene
                                       13

-------
In addition, review of  the  Endangerment Assessment by EPA and Ecology resulted
In the inclusion of three additional  indicator chemicals listed below:

     o    xylenes
     o    1,1,1-trlchloroethane
     o    ethyl benzene.

The rationale for Inclusion of these  chemicals Is discussed further In the
Endangerment Assessment  section of  this document.

     Twenty three private drinking  water wells were sampled during the
sampling program.  For  the  three wells where contamination exceeded drinking
water standards, the City of  Tacoma connected the residents to City water.
As the plume spreads. It is predicted more  private wells would become
contaminated at levels  above  public health  standards unless actions are taken
to restrict the movement of the plume.

     A list of hazardous organic compounds  (priority pollutant and hazardous
substance list compounds) detected  in groundwater samples analyzed during the
RI Is given in Table 3.  Table 4 provides the list of priority pollutant
metals detected at the  landfill.

     C. Extent of Ground Water Contamination

     The contaminant pathway  of primary concern near the landfill is the
ground water.  The town of  Fircrest supplies water to its residents from six
 ells located west of the  landfill.  Three  of these wells are only
                                        14

-------
Uj>t« CuBH'OI'ClU

Volilllt Ot««iilc  CoiBPoundi
   T«l t achloKMthin*
   TIUII- 1 . 2-Dlcltloro*th*n«
   Tt lcliloro«ih«ii«
   I , l-Dlcliloro«lh*n«
   Vinyl Clilorld*
   1,1. 1 -rt lchloro«lhui«
   I. l-Dlchlofo«llt*M
   1.2 DIcMoiodliaiM
   Clilot ob«ni«it«
   Tuliicna
   XyUiM (Tool)
   2 • Buiftnoii*
   2 ll*«aikoii«
   1.2. -Dlcliloropcop*n«
   T(*III- I , l-Dichloioprop«n«
   Slycin*
   (Uibon D I lull Id*
   Qilorotor*
   K*thyl«n* Otlocld*
   Ac«ton*
   4-H*ilirl -2-p*n(»non«
   PMA.
   Ph«nol
   rtlulcl* Etltrt
   1 ,«-OUhlo(ob«n<«n«
   H-Hltro-Sodl-
     ph*nf IMMH*
   ft*iujfl Alcohol
   ••mole Acid
                                                                  TABLE 3
                                   ORGANIC  HASTE COMPONENTS  DETECTED  AT  THE  TACOMA  LANDFILL
Subiurfac*
   Soli
                                                                    Ground-
                                                                                       Surfcc*
                                                                                                            _£**'_
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X
                           X

                           X
                           X
X
X
X
X
X
X
X
X
X
                        X
                        X
                                                                    x
                                                                    i
                                                                    i
                       X
                       X
 x
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
 X
X
X
                                                                    X
                                                                    X
                                                                    X
                                                                    X
   l«ophoio
• S*^>1«* not »rv»ljrt«d lor  •••Ivolctll* compound*

b Oiilr tr*c« tmounlt  of •••IvoUcll* oo^iound* w*r« d«t*ot«d in (round utttr

-------
                                TABLE 4
                 METALS DETECTED AT TACOMA LANDFILL
Subsurface Ground-
Soil water
Arsenic
Cadmium
Chromium
Copper
Mercury
Nickel
Lead
Zinc
Iron
Aluminum
Manganese
X

X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NA
X
Surface San. Sewer Sediment
Hater & leachate
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NA
X
X
X
X
X
X
X
X
X
X
X
X
Gas
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA* not appl1 cable

-------
 approximately 0.2 mile  from  the  edge  of  the  landfill.   The City of Tacoma
 operates nine wells  to  the east  of  the  landfill  to supplement summer  peak
 demands on their surface water supply (see Figure  2).   In  addition, twenty-six
 known domestic wells are located near the landfill  (see  Figure  6).

     Volatile organic compounds  have  been detected  In .20 monitoring wells
 Installed around the perimeter of the landfill during the  RI  and  In six of the
 private wells.  The highest contaminant concentrations and  greatest numbers of
 compounds were generally found near the water table  in the  southern portion of
 the landfill.  Hater samples from monitoring wells TL-4, TL-3a. TL-lla, and
 TL-12 Illustrate this occurrence.  However,  the highest  concentration of vinyl
chloride detected to date on the site was drawn from a deeper portion of the
aquifer at monitoring well  TL-lOb.

     Contour  maps Included In the RI report show the projected distribution of
seven of the  contaminants of concern  in the  aquifer associated with the Tacoma
Landfill  Site:
                                             Maximum Concentration
     a.    Vinyl  chloride                          80 ug/1
     b.    Benzene                                 19ug/1
     c.    1.2-dlchloroethane (DCE)                20 ug/1
     d.    Metnylene chloride                    1300 ug/1
     e.    I.l-d1ch'-roethane (OCA)                42 ug/1
     f.    Chloroethane                            55 ug/1
     h.    Toluene                                 60 ug/1
                                       15

-------
CONTAMINANT DISTRIBUTION IN GROUNDWATER
VINYL CHLORIDE
1,2-OICHLOROETHANE
                                BENZENE
                          M€TMYLENE CHLO«ID€
CONCENTRATION CONTOURS IN UG/L
                                            FIGURES
                                            CONTAMINANT
                                            IN GROUNDWATER

-------
     CONTAMINANT DISTRIBUTION IN GROUNDWATER
   • • i
HBCJUIT .
\n. 17
   n»*«i
     1
 rw-a*
          •»*'
  .-U.-<
      ••p
     ..--•TV*
     • ^^^ >  «<
     :; •""  ~'
       L-/O
      ^
      i7~1
      U J_J
      ::^
      m.
      1X1 ,|

      clii

    ,n
               JL '3;
  rw-i
          ^     /
          «, 1 .rr. f  /
    1.1-OtCHLOROETHAWE
         TOLUENC
  f



*L
                                    CHLOROfTHAHi
                 CONCENTRATION CONTOURS IN UG/L
                                        TC£

                                         FIGURE 10
                                         CONTAMINANT DETRIB
                                         IN GROUNDWATER (COt

-------
The contour maps are 0resented here as Figures 9 and 10 to show the general
pattern In which each contaminant has spread In the aquifer.

     Priority pollutant semlvolatlle. base, neutral, and acid extractable
compounds were detected In trace amounts In a few of the ground water samples
collected at the site.  Priority pollutant metals occasionally exceeded
maximum contaminant levels (MCLs) established pursuant to the federal Safe
Drinking Hater Act.

     1,1,1-trlchloroethane was also found  In measurable amounts In wells along
53rd Street West.  Routine sampling of these wells has been on an annual basis
                                            \^
and It Is possible that the landfill is not the only source of contamination.
This Is In the process of being evaluated.

     D. Surface Water

     Surface water testing throughout the  study area, In general, did not show
a significant problem which could be attributed directly to the landfill.  At
this time most of  the surface water Is being controlled on-slte.  There are
three notable exceptions to surface water  control:

     1.   The retention pond to the north  has been contaminated with toluene.
          This chemical has also been detected In nearby monitoring well TL-17.

     2.   Nearby off-site storm sewers receive runoff which discharges to
          surface  water (Leach and Flett Creeks) without retention or
          pre-treatment.
                                        16

-------
      3.    Storm water from the landfill Is being conducted to the sanitary
           sewer.

      Leachate was surfacing on the working face that now comprises the  east
 side  of  the  Central  Area.  The leachate Is now being conducted directly to the
 sanitary sewer through a burled toe drain.

      Sediment samples taken from nearby storm sewer  outlets  show  elevated
 values for metals.   However the RI was  Inconclusive  citing other  potential
 sources  in addition  to the landfill.   Surface water  (storm water  runoff) will
 be addressed  as  part of  the selected  remedy.

     E.  Future Impacts

     As  part  of  the  RI/FS,  modeling was  performed to  project future
 contaminant migration.   Contamination has  been  verified  In private wells
 southwest of  the  landfill  In  the  direction of Leach Creek.

     Tentative flow  paths  were  then plotted based on  the mapping of ground
water levels  over several  months.   Contaminant  flow velocities and dispersion
ratios were then  estimated  and  a  simplified groundwater contaminant transport
model named Plume (Van der  Heijde  1983)  was run.

     Receptor groups  were  assigned  based on location of known contamination
and the assumed aquifer  discharge.  Wells closest to Orchard Street were
designated near.  Wells  downgradient from the near wells were called far.
Leach Creek was assumed  to  be the  far boundary.  The Fircrest wells were not
                                       17

-------
included In the model because  the  flow path analysis did not show them in the
line of contamination.  However, the  flow path analysis was based on current
usage rates and pumping conditions of both Fircrest and the Tacoma wellfleld,
and did not take Into account  any  future changes to these conditions.  The
Feasibility Study (FS) did not include flow path analysis under differing
usage rates and pumping conditions.   Therefore, the model is appropriate for
prediction of future migration only as far as the assumptions remain valid.

     The studies showed that the main plume of groundwater contamination may
reach 1200 feet southwest of the landfill.  To the west and southeast It may
reach 200 feet and to the northeast about 800 feet.  Figure 11  shows this
plume and how far it would spread  if  unchecked, and If the model  assumptions
are correct.  The modeling that helped predict the plume's spread assumed tha
pumping of the Fircrest and City of Tacoma <6a) wells will stay the same.
These wells are about 500 and  3500 feet from the site, respectively.

     The model predicted that  for  the next 100 years the aquifer between the
landfill and Leach Creek would contain unacceptable levels of contaminants.
Table 5 lists the estimated maximum predicted off-site concentrations for the
seven Indicator chemicals In the RI,  and the estimated times to reach maximum
concentrations at the dose In and distant wells.
                                        18

-------
             FIGURE 11
CURRENT AND PREDICTED CONTAMINATION

-------
      F.    Endangerment Assessment




      An  endangerment assessment was conducted at the Tacoma Landfill  to


 estimate the magnitude and probability of actual or potential  harm to public


 health or the environment caused by the threatened or actual release  of


 hazardous substances.  The assessment presented in the RI addressed the


 potential human health and environmental  effects associated with the  Tacoma


 Landfill  site In the absence of the any remedial action (I.e.,  the no action


 alternative).




      The  no  action  alternative Is  the baseline where  no corrective actions
                                            ^

 take  place under Superfund.   In the case  of the Tacoma Landfill,  however,


 certain  corrective  actions will take place  regardless  of the actions  taken


 pursuant  to  the Superfund site cleanup.   These corrective actions  must  be


 conducted to  meet the requirements  of the Washington  State Minimum Functional


 Standards for  landfills  (MAC 173-304).  These  actions  Include: developing an


 operating and  closure plan for the  landfill,  Installation of a cap,


 Installation of a liner  and  leachate collection  for ongoing disposal


 activities, and Installation,  operation and maintenance  of a methane  gas

 extraction system.




      The  future operation and  maintenance of the landfill  gas extraction


 system and planned  refuse processing operations  will restrict development of


 the landfill.   Therefore,  the  endangerment assessment  for  the no action

 alternative assumes  site  access will continue  to be restricted in  the future.


Although  several  pathways  of exposure can be postulated  for  the site (surface
                  -*
 runoff.  Inhalation of vapors and entrained dust), the primary pathway of


 concern for this  site is  groundwater.  Since access to the  site will be



                                       19

-------
restricted, the Importance of the air pathway will be reduced.  The methane
gas collection system will also act to minimize the inhalation exposure
route.  The target receptors are the private and public well owners within the
path of contaminant plume.  Also of concern Is the possibility of heavy metals
and organics reaching Leach Creek, and ultimately Puget Sound, either by
surface or groundwater routes.
Health Evaluation

     The public health evaluation Identifies potential threats to human health
In the absence of remedial action at the site.  This evaluation process
Includes a hazard assessment, dose/response assessment, exposure assessment
and risk characterization.

     Twenty-four volatile organic chemicals were detected In the groundwater.
Of these, seven were selected as contaminants of concern In the Endangerment
Assessment of the RI due to their frequency of occurrence, concentrations
found, and primary targets (human population):

          o    vinyl chloride
          o    benzene
          o    1,2-dlchloroethane
          o    methylene chloride
          o    1,1-dlchloroethane
          o    chloroethane
          o    toluene
                                       20

-------
      However, based .on EPA and Ecology's review of the Endangerment
 Assessment,  the following three additional  organic chemicals have been added
 to the list  of contaminants of concern:

           o     xylenes
           o     1,1,1-trlchloroethane
           o     ethyl  benzene.

      This  new list  of ten organic  contaminants  of  concern  were  separated  into
 classes of potential  carcinogens and noncarcinogens.   Vinyl  chloride,  benzene,
 1,2-dlchloroethane.  and methylene  chloride  were selected as  Indicator
 potential  carcinogens.  Both vinyl  chloride and benzene are  classified  as
 human  carcinogens by  the  EPA.   Methylene  chloride  Is  a B2, probable human
 carcinogen,  based on  Inadequate data In humans  and  Increased  Incidence  In rats
 and mice.  It  Is present  both on and off-site at considerably less frequencies
 of occurrence..  1,2-d1chloroethane,  despite being  found even less frequently
 than methylene  chloride,  is ranked  as an  EPA 82 carcinogen and  Is Included for
 that reason.

     Chosen  as  noncarclnogen Indicator chemicals of concern were
 1,1-dlchloroethane,  chloroethane, toluene,  xylenes, 1,1,1-trlchloroethane, and
 ethyl benzene.  The three  chlorinated ethanes were encountered relatively
 frequently In the samples, although  1,1-dlchloroethane occurs much less
 frequently than the others.  In general,  the toxicity  and bloconcentration
 potential  of the chlorinated ethanes  Increases with Increased concentration.
All but the  1,1,1-lsomer are extremely soluble  in water.   Toxicity concerns
                                       21

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from their Ingestlon.at significant  levels  in drinking water  lie chiefly In
the areas of chronic liver damage and overall central nervous system
depression.

     Toluene and xylenes were selected  largely because of their high
frequencies of occurrence, chemical  similarities, and potential ecological
risk.  Toluene was the most commonly detected chemical in water samples
off-site, and was roughly equivalent to xylene as fourth most common on-site.
Ethyl benzene was Included as a chemical of concern because of Its relatively
frequent occurrence among the more minor chemicals, its leachabi11ty, and its
tendency to blodegrade relatively slowly in groundwater.

     The Endangerment Assessment of  the RI calculated the excess lifetime
cancer risks from Ingestlon of carcinogens  in groundwater If no alternate
water supply Is provided, and an estimate of risk if there Is short term
exposure to the Indicator chemicals.  Because so many chemicals, both
carcinogens and noncarcinogens, are  present in the groundwater, the
possibilities of addltlvlty and synerglsm cannot be Ignored.  However, the
Endangerment Assessment of the RI was largely modeled on the concept of the
predominant risk being due to the Ingestlon of water containing vinyl chloride

     The calculation of carcinogenic risk, assuming no alternate water supply
1s provided, is based on a 70 kg adult consuming 2 liters of contaminated
groundwater for 70 years.  The Increased risk of cancer If a 70 kg adult
consumes 2 liters of vinyl chloride  contaminated groundwater (at a
concentration of 70 ug/L) for 70 years  Is about 5 In one thousand.
                                       22

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      Carcinogenic  risks  have been calculated for the short term exposure
 scenario,  that  a  carcinogen  migrates  to  a  residential  well  the day after a
 "carcinogen  free"  sample  is  collected.   It Is  estimated  It  will  take
 approximately four months  from  the  start of exposure until  contamination Is
 detected  In  the next  quarterly  sample and  before  an  alteVnate  water supply can
 be provided.  The  short  term concentration  was estimated  based on  sampling
 results for  the residential  wells  In which  contamination  has been  detected.
 The average  dally  Intake was  then calculated to account for the  four month
 exposure.  The estimated excess cancer risk  associated with this short  term
 exposure  Is  less than one  In  a million.
                                            \
     The population at risk  within  the predicted plume Is divided  Into  three
 areas:  the area within City  boundaries,  the area within  the Town of Flrcrest
 boundaries, and the unincorporated area within Pierce County.  Approximately
 half of the predicted contaminant plume Is east of Orchard Street within the
 Tacoma City limits.  There are approximately 26 residences within the
 projected plume. If contamination continues to flow predominately toward the
 southwest.  Groundwater sampling and hydrogeologlcal  Investigations  conducted
 during the RI Indicate that the plume has reached the existing wells closest
 to the landfill.  Those with close-in wells In which  contaminants have been
detected have been connected to City water.

     There are still  three close-in wells not hooked  up to City water In which
contaminants  have  not been detected.  No  contaminants have been detected 1n
the distant wells,  and based on  the contaminant transport modeling.  It will be
 several  years before  the  wells In this  group will  be  Impacted  as a  result of
contaminant migration from the landfill.
                                       23

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     Table 5 lists the estimated  landfill  source concentrations for the seven
indicator chemicals listed  in  the RI and the estimated times to reach maximum
concentrations at the close-in and distant wells.  The close-in wells would be
expected to be maximally  Impacted by vinyl chloride beginning about 10 to 15
years from now while benzene would not be  expected to peak until about 55 to
60 years hence.  The distant wells would be expected to reach maximum benzene
concentrations In about 85  to  90 years.

     There Is a possibility that  if water  from Leach Creek was used In the
future as a drinking water  supply, exposure to vinyl chloride and/or benzene
at levels exceeding their MCLs could occur.  There are existing water rights
for domestic use of Leach Creek.

     Some potential exists  for human exposure to contaminants by using private
well water for livestock  and to water vegetables, etc.  However,, since the
contaminant concentrations  of  the groundwater being used to water livestock
and Irrigate crops would  be the same as detected in the private wells. It
would be highly unlikely  that  a significant exposure would result from this
pathway.

Environmental Evaluation

     The Endangerment Assessment  In the RI did not compare the levels of
organlcs and metals In the  groundwater to  ambient Water Quality Criteria (WQC)
for the protection of aquatic  life.  Metals and organic compounds in the
groundwater which are above federal or state WQC are of environmental
concern.  Maximum concentrations detected  In either on-site or off-site
                                       24

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                                 TABLES

            TRAVEL TIMES TO REACH MAXIMUM AND THRESHOLD
            CONCENTRATIONS, CLOSE-IN AND DISTANT WELLS
Indicator Chralcal

Vinyl Chloride(1)
Benzene (1)
1,2-Dlchloro« than*(I)
Mathylene Chlorlde(l)
1,l-Dlchlo roc thane(2)
Chlo roe than* ( 2)
Toluene(2)
Predicted
Offslte
Cone.
   ug/L

 60-70
  3-10
  4-5
150-160
 30
 30
 30
Tlaa from Present
to Approach Max.
Concentration, Trs.
Clo««-Ia   Distant
 Veils     Veils
10-15
55-60
45-50
 5-10
35-40
 5-10
55-60
25-30
85-90
75-30
20-30
65-70
20-25
85-90
         Threshold
         Cone.
            ug/L
   2
   5
   5
  36,
 271.
5
27
(V.ry High)
2000
Tla« From
Pr«a«nt to
Back B«lov
Threshold
   Trs

 >100
 >100
  SA
 >100
  HA, >100
  HA
  NA
HOTZS:
(1)  Maxiaoa conccntratlona for carcloogena art aazlaua 70 years av«raf«.

(2)  K*rt*nm concentratlooa for noncarclnogeoa are «a-rf«T» 90 day» a-rerage.

-------
 groundwater  for  cadmium,  chromium,  copper,  nickel  and zinc,  all  exceeded
 ambient  WCC  for  the  protection  of aquatic life.   An overview of  the VOCs which
 were  identified  as potentially  harmful  to the environment  are listed in  Table
 3.

      Flett and Leach Creeks  support  anadromous salmonid  runs,  which will  be  at
 risk  If  toxic compounds are  present  in  the  creeks  during critical phases
 (e.g., smelting)  In  their  growth  cycles.  Heavy metals,  as well as  certain of
 the organlcs such, as xylene  may also pose problems  for the health of the
 downstream wetlands  ecosystem as  the Leach  Creek drainage ultimately enters
 Puget Sound.  This would most markedly  impact highly  vulnerable organisms such
 as larval fishes, but parts  of the commercially Important benthos (shellfish)
 could also become adversely  affected.

Conclusions

     Based on a review of  the endangerment assessment and data presented In
the RI report,  the following conclusions were made concerning risk  to human
health and the environment from contaminants associated with the  Tacoma
Landfill  site:

     o    Concentrations of  several  Indicator chemicals frequently exceed MCLs
          In the groundwater-  Drinking the water  from contaminated  wells
          poses  the most significant risk to human health,  especially In  terms
          of chemicals  In the aggregate.
                                       25

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o    Under the.no  action  alternative,  some  contaminant  concentrations  In
     the groundwater  plume  are predicted  to exceed  ambient WQC when the
     plume discharges  to  Leach Creek.   These levels  could pose a risk  to
     aquatic biota, especially since  the  Leach  and  Flett Creeks wetland
     area enters Puget Sound.

o    Based on  EPA  and  Ecology's review of the Endangerment Assessment  In
     the RI, the agencies agreed  that  It  would  be appropriate, for the
     protection of public health,  to  establish  health-based levels for a
     larger number of  compounds than  the  seven  Indicator chemicals
     selected  during  the  risk assessment.   Accordingly, xylenes.
                                       X
     1,1,1-trlchloroethane  and ethyl  benzene have been  added to the list
     of  contaminants of concern.

o    Depending on  the  discharge location, performance levels for the
     selected  remedy will be based on  MCLs,  Water Quality Criteria, or
     pre-treatment standards.  In  the  absence of established standards or
     Hater Quality Criteria, EPA  Region 10  has  conducted a risk
     assessment of the compounds.  These  are listed  1n  Table 8 of the
     Selected  Remedy  portion of this  document.  The  most stringent number
     will be used  for  the performance  levels for the treatment system  If
     the cleaned water Is discharged  to surface water.  For the other
     volatile  organic  chemicals and metals  found In  the groundwater, EPA
     and Ecology have  identified  a methodology  for establishing
     performance levels.  This methodology  1s detailed  In the Selected
     Remedial  Alternative section  of  this document  (Section VI).
                                  26

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 V.    SU« OF ALTERNATIVES EVALUATION
      A. Identification and Screening of Remedial Technologies

      In order to develop  a complete listing of potential remedial technolo-
 gies,  general  response  actions  corresponding to each contaminant pathway were
 Identified.

      The  general  response  actions  fall  Into the following seven primary
 categories:

     o    No  action
     o    Institutional controls
     o    Containment
     o    Removal
     o    On-slte treatment/discharge
     o    Off-site treatment/disposal
     o    Other management options.
                           /

     Forty potential  remedial technologies for  cor. ;rol ling contaminant
migration were screened.  Thirty-one potential  remedial  technologies were
Identified for the groundwater pathway and nine potential remedial
technologies were Identified for the gas migration/air quality  pathway.  The
potential remedial technologies were categorized according to the appropriate
general response action.  A screening process was applied to these to Identify
unsatisfactory technologies.  Screening criteria were effectiveness,
Implementabl 11 tyVand cost.
                                       27

-------
     The technologies that were not screened out were assembled  Into
preliminary remedial action alternatives.   These alternatives were designed  to'
meet the categories identified by the National Contingency Plan  
-------
 Institutional  concerns.   Requirements of the NC? were met by evaluating each
 alternative with respect to the following criteria:

      o    Technical  Feasibility
      o    Public Health  Impacts
      o    Environmental  Impacts
      o    Institutional  Requirements
      o    Cost  Analysis.

 This  analysis facilitates  the  comparison  of  similar components  among the
 alternatives for the  same  criteria.
Technical Feasibility

     The technical evaluation considered  the performance,  reliability,
Implementabl11ty, and safety factors of the remedial actions.   Performance of
each alternative was based on the alternative's expected effectiveness  and Its
useful life.  Key considerations In evaluating reliability  Included operation
and maintenance (O&M) requirements and the demonstrated performance of  the
technologies at similar sites.  While SARA requirements do  not  Include
demonstrated performance, the six final remedial alternatives evaluated
against this criteria were known technologies. For Implementablllty. both the
constructablllty and the time required to achieve a given level of response
were considered.  Constructablllty addresses whether the alternative can be
constructed on the site and the Impact of external conditions on the
construction.   The.time It takes to Implement an alternative and the time to
                                       29

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achieve beneficial results that attain or exceed relevant or applicable
standards were also considered.  The safety evaluation considers short-term
and long-terra threats to the safety of nearby residents and to persons working
on-s1te.  Major risks to consider are exposure to hazardous substances, fire,
and explosion due to activities conducted during Implementation of the
remedial action.
    jc Health Impacts

     The public health evaluation of alternatives assesses the extent to which
                                             \
each alternative mitigates long or short-term  exposure to any residual
contamination and protects public health during and after completion of the
remedial action.  In evaluating both long and short-term public health
Impacts, two primary areas were considered.  Evaluation of short-term Impacts
considered health effects on workers during construction of the remedial
action and on the public for the Interim period prior to remedial action
Implementation.  Long-term Impacts were judged based on chronic Intake of the
contaminant over a lifetime.
             Impacts
     Each remedial alternative was evaluated for beneficial and adverse
environmental Impacts for the long and short-term.  Criteria for evaluating
beneficial effects were final environmental conditions. Improvements In the
                                       30

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 biological  environment, and improvements in resources people use.  Criteria
 for  evaluating adverse effects were the expected effect of the remedial action
 and  the  measures  taken in the event Inevitable or Irreversible effects occur.
 Institutional Requirements

      Institutional  requirements  are divided  into three categories:  community
 concerns, conformance  with  Applicable  or Relevant and  Appropriate  Requirements
 (ARARs). and permitting  requirements.   Community concerns  addresses  the
 public's acceptance of the  selected remedial  action  alternatives.   The
                                            N
 remedial action alternatives  developed In  the  FS should  address  all  legally
 applicable or relevant and  appropriate standards,  requirements,  criteria, or
 limitations to be consistent  with  SARA.   Institutional constraints are those
mechanisms available to  ensure administrative  control  over activities at the
 site (zoning, permits, ordinances,  etc.).
Cost Analysis

     Detailed cost analysis of alternatives Involves estimating the expendi-
tures required to complete each measure In terms of capital costs, and annual
operation and maintenance costs for a 30-year period.  Once these values were
determined and a present worth calculated for each alternative, a comparative
evaluation was made.  The cost estimates presented In the FS section were
based on conceptual designs prepared for the alternatives (I.e., without
detailed engineering data).  These estimates were accurate between +50 percent
and -30 percent In 1987 dollars.

                                       31

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Rating Alternatives

     A rating system Is used to evaluate alternatives, and the terms high,
moderate, and low are assigned to each.  A high rating Indicates that the
alternative promotes the Intent of the criterion and/or meets or exceeds the
remedial objectives.  A moderate rating indicates that the alternative only
partially promotes the intent of the criterion; however, the alternative does
remediate the problem to an acceptable extent even though It does not meet all
the remedial objectives.  A low rating Indicates that the alternative does not
promote the criterion and/or does not meet the remedial objectives.

                                            \
     An evaluation of each alternative Is contained In Tables 6 and 7.  These
evaluations are based on numerical ratings of each criterion contained In the
FS (Black & Veatch 1987).  A criterion was subdivided Into one or a few
factors, which were rated from 1 to 5.  To establish the criterion numerical
rate, numerals assigned to each factor within the criterion were averaged.
For this report, ratings were assigned as follows:

          Numerical Rating               New Criterion Rating
                 £2.00                    High
                  2.01-3.99               Moderate
                 >4.00                    Low
                                       32

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                                                               TABLE 6
                                       SUMMARY OF DETAILED EVALUATION OF REMEDIAL ALTERNATIVES


No.
,
2

Cost

Alternative (No. In (S) Capital
No Actlonjl)
Alternative Water Supply/
Landfill Cap (J) 16.423
($1.000)
Present
Worth
--

IB',376

Public
Health Impacts
LOM

High

Environmental
(•pacts
LOM

Moderate
Criterion
Technical
Feasibility
N/A

High

Institutional
Requirements
LOM

High

Community
Concerns
LOM

High
Pump. Treatment, and
Discharge with Landfill  Cap

a.  Off-site Treatment at
    Sewage Treatment
    Plant (2)

b.  On-slte Treatment (Air
    Stripping and Carbon
    Adsorption (4)
         *
c.  On-slte Treatment
    Carbon Adsorption (8)

d.  On-slte Treatment
    (Air Stripping) (I?)
17.91?
23,418
High
High
Moderate
High
High
19.532
19.266
18.971
22,717
23.417
21.015
High
High
High
High
High
High
Moderate
Moderate
Moderate
High
High
High
High
High
High

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                                                         TA8LE 7

                                             SECTION  121(b)  (1)  (A-fi)  FACTORS
—
Criterion 1
Compliance with ARABS Low
Reduction of To*1dty.
Mobility. volune Lo«
Short-Term Effectiveness Low
Long-Tern effectiveness Low
Implement ability N/A
Cost (See Table 6)
Comnunlty Acceptance Low
State Acceptance Low
Alternative
2 3a
\
Moderate High
Moderate High
High Moderate
Moderate High
High Moderate

Moderate High
Moderate High
3b
High
High
Moderate
High
Moderate

High
High
JC
High
High
Moderate
High
Moderate

High
High
Id
High
High
Moderate
High
Moderatt

High
Moderate
Overall Protection of
HUMUI Health and the
Environment
Low
Moderate       High
High
High
                                                                           High

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 C. Results of Detailed Evaluation of Remedial Alternatives

      This section presents a summary of the detailed evaluation of the
 remedial  alternatives In terms of costs,  public health Impacts, environmental
 Impacts,  technical  feasibility,  institutional  requirements, and community
 concerns.   A summary of these  Items  Is  presented in Table 6 according to 1985
 RI/FS  Guidance  Factors  (EPA 1985)  and an  evaluation of the remedial
 alternatives according  to the  Section 121(b)(l)(A-G) factors is shown In
 Table  7.
Non-cost Evaluation

     As shown  In Table  6. Alternatives 2, 3a. 3b,  3c.  and  3d  all  had  four  high
ratings and one moderate rating.  Therefore, they  would  be Judged comparable
alternatives under this system of rating criteria.  However,  evaluating
alternatives using guidance from Section 121
-------
Cost Summary and Sensitivity Analysis

     Cost estimates prepared for each alternative  Involved approximation,
assumptions, estimations. Interpretations, and engineering Judgment.  To
provide some Indication of sensitivity of the costs  to changes In key
parameters, a sensitivity analysis was performed.

     The cost of closing the landfill Is the major cost for all the
alternatives under consideration, and Is the same for each.  The treatment
process cost could be-the most variable because alternatives would not yield
the same Influent concentrations.  To evaluate the Impact that changes in
concentration would have on carbon adsorption treatment costs, concentrations
of two and three times the predicted value were analyzed.  The carbon
adsorption unit cost was chosen for analysis on the  basis of Its potential
Impact on overall treatment cost estimates of Alternatives 3b and 3c.  When
the concentration of contaminants In the waste stream Is doubled, the carbon
usage (cost) will Increase by approximately  1.5 times.  The total cost for
Alternative 3b would Increase 3.8 percent while the  total cost for Alternative
3c would Increase 6.8 percent.  For the case when the contaminant
concentrations are tripled, the carbon cost will approximately double.  The
total cost for Alternative 3b would Increase 7.3 percent while the total cost
for Alternative 3c would Increase 9.7 percent.
                                        34

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VI.  SELECTED REMEDIAL ALTERATIVE  (No.  3)

     A.   Description of Selected Remedy

The selected remedy Includes a landfill cap and gas extraction  system to
control the source, and a ground water extraction and treatment system to
control migration of the plume.  All extracted water will be treated to
specific performance standards, monitored to ensure compliance and will  be
properly discharged.  The Tacoma water supply system will be expanded to
assure sufficient water Is available should any water supply (public or
private) become contaminated from the landfMl.  The remedy also Includes a
closure schedule for operation of the landfill.

The remedy Is  designed to:

     o    Prevent further migration  of the plume via the ground water
          extraction-treatment system.
                          /
     o    Reduce the production of leachate by placing constraints  on site
          operations and  by properly grading and capping the landfill.

     o    Eliminate off-site gas  migration through  the gas extraction system.

     o    Further protect public  health  and the environment via monitoring of
          groundwater,  surface  water,  gas  probes,  air  emissions,  and
          provision of alternate  water  supplies where  necessary.
                                       35

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     Management of Migration

     Migration control will be achieved through a ground water extraction and
treatment system, and a system or method to confirm performance.  Activities
necessary to develop those systems shall be conducted during remedial design.
Hells for this system will be placed within and. If necessary, downgradlent to
contain the plume.  Containment Is defined as controlling the plume and
preventing the spread of contamination.  The goal of the containment system is
to prevent any further degradation of existing water quality beyond the
boundaries of the existing plume.  The extraction wells should be designed to
achieve this objective.  The existence of the gradient reversal due to pumping
                                            N
by the city of Tacoma well field, local effects from pumping the Fircrest
wells, or monitoring results at the landfill may result In the need for
extraction wells at locations other than those Identified In the feasibility
study.  Minimum flows as required by WAC 173-512 shall be maintained In Leach
and Flett Creeks.

     The treatment process shall be permanent and shall effectively reduce the
toxlclty. mobility, and volume of contaminants.  It shall also employ all
known, available, and reasonable methods to treat the contaminated ground
water, and to prevent the spread of contamination.  Discharge of treated
ground water may be to either Leach Creek, Flett Creek, or the sanitary sewer.

     If the discharge Is to either Leach Creek or Flett Creek, the effluent
must meet or exceed maximum contaminant levels (MCLs) developed pursuant to
the Safe Drinking Hater Act or meet the chronic fresh water criteria as set
forth In EPA's Quality Criteria for Hater. 1986 (EPA 440/5-86-001). whichever
                                       36

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 is  more  stringent.   Both of these creeks have existing water rights en them,

 although  they are  closed to further appropriation by MAC 173-512.  In

 addition,  both creeks  support anadromous salmonid runs.

                                                          *

     Most  of  the contaminants found at the Tacoma Landfill  do not currently

 have MCLs.  For the  VOCs listed  in  Table 3,  and  for metals  in the groundwater,

 which EPA  and  Ecology  have  not established treatment levels,  a  methodology  for

 determining the appropriate discharge  limits has  been established.   If no MCL

 has been established for a  contaminant,  the  ambient water  quality criteria

 (HQC) for  protection of  human health for water and  fish ingestlon will  be

 used.  If  the  value  for  protection  of  fish  (the chronic fresh water  criteria)
                                            X
 Is  lower than  the value  for protection of human health,  the  lower value will

 be applied.  If there  are no WQC  at all,  then additional guidance documents,

 such as Health Advisories from EPA's Office  of Drinking Hater or  any

 appropriate toxlcologlcal profiles, will  be  used  to develop  treatment  levels.

 These treatment levels must be reviewed  and  approved  by both  Ecology and EPA

 prior to their use.  This methodology will be used  to set performance  levels

 for any other contaminants  Identified  In  the groundwater and  traceable to the

 landfill.



     For six of the volatile organic compounds listed  In Table 8. appropriate

 treatment levels have been  Identified.   These are based on Safe Drinking Hater

Act MCLs or ambient HQC.  In  the absence of an MCL or ambient HQC,  EPA Region

 10 conducted a risk assessment of the chemical and provided an appropriate

 treatment goal for the protection of public health, welfare and the

environment.   These goals are  listed In column three of Table 8 and will be
                -»
used as  performance goals for the treatment system.   In addition, the effluent
                                       37

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                               TABLES

            PERFORMANCE LEVELS FOR TREATMENT SYSTEM
                    DISCHARGE TO SURFACE WATER
                         TACOMA LANDFILL
(ug/L)




Constituent
Benzene
Chloroethane
1 ,1-dlchloroethane
1 ,2-dlchlorcethane
Ethyl benzene
Methylene chloride
Toluene
1 ,1 ,1-trlchloroethane
Vinyl chloride
Xylenes
Safe
Drinking
Hater Act

MCL
5


5



200
2



Water Qual i
Hater and(l)
Fish
0.66*

s
0.94*
1.400

14
18.400




tv Criteria
Chron1c<2)
Fresh water
53


20.000
320

175




EPA
Req. 10
R1sk<3)
Assess.

20
20


5*



10
(1)   EPA Quality Criteria for Hater, 1986 EPA 440/5-86-001. for water  and
     fish  Ingestlon by humans.
(2)   Chronic fresh water criteria  for protection of  aquatic life.
     Where no values for chronic exposure were available, the acute
     values were divided by 100.
(3)   Based on EPA Region 10 Risk Assessment.
 •   Values presented for carcinogens are at the 10~6  risk level.

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 must  meet  water quality standards as set forth In 173-201 (Water Quality
 Standards  for Haters of the State of Washington).

      If  the  option  of discharge to the sanitary sewer Is chosen,  it must be
 consistent with discharge  limitations  as defined  by  HAG 173-216 (State  Waste
 Discharge Program)  and must meet pre-treatment regulations  (City  of Tacoma
 Code, Chapter 12.08).  as  revised for operation of the secondary sewage
 treatment plant.

     Any treatment  system  which results  in  contaminant  air  emissions shall be
 designed to  address  appropriate ambient  air quality  values  as  determined by
 Ecology's Draft New  Source  Review Guidelines for  Toxic  Air  Contaminants.
 (September 1986, or  as  revised).   In addition,  the Puget  Sound  Air  Pollution
Control  Authority (PSAPCA)  has  made  the  determination that  all  new  sources
 shall  use Best  Available Control  Technology (BACT).   This also  will be a
requirement of  the treatment  system  design.  BACT may Involve a different
technology for  different contaminants.

     The extraction  and treatment  system can be shut off when water quality
within the plume, outside the compliance boundary (defined by WAC 173-304 as
the edge of the filled area), consistently meets or exceeds drinking water
standards, or previously established and approved health-based criteria.  In
addition to meeting  health-based  criteria, potential impacts to public and
private  water supplies and  to Leach Creek must be considered In the decision
to shut  off the system.  Ecology and EPA will  reevaluate the Implemented
system every five years to  assure  that It Is working properly and to propose
any modifications'that could facilitate the cleanup of the groundwater.
                                       38

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     Source Control

     Source  control  measures  consist  of constructing a cap on  the  landfill  to
minimize  Infiltration  and  maximize  run-off.   Unllned areas of  the  landfill
will be capped  as  soon as  possible.   WAC 173-304 defines  the minimum
requirements  for a cap on  a municipal  landfill.   A  more  stringent  cap  will  be
required  unless further analysis  of the cap,  to  be  provided during  remedial
design, shows that a significant  reduction  In  leachate volume  or toxlcity
would not be  achieved.

     Increased  run-off due to  the construction of the  cap  will be routed off
                                            \
the landfill  to reduce  infiltration.   The slope  of  the cap  and construction of
drainage  structures will be consistent  with HAC  173-304. The run-off collected
from the  landfill  will  be directed to  the appropriate  storm or sanitary
sewers, consistent with  local  storm drainage ordinances or  pre-treatmerit
regulations.  The  storm  drainage plan,  prepared  as  part of  the remedial
design, will determine  and minimize any downstream  Increases In peak flow.

     The Minimum Functional Standards (MFS) (HAC 173-304) prohibit filling In
unllned areas after November 1989.  These standards contain specific liner
requirements which will  apply  to all municipal landfills by this date.
Compliance with Minimum  Functional Standards Is determined by TPCHD, In
accordance with Ecology  review.  Insufficient Information has  been received by
Ecology and TPCHD to evaluate  compliance of the  liner Installation with
Minimum Functional  Standard requirements.  If the liner Is determined not to
be In compliance,  a variance will  be required from TPCHO to operate the
Central Area PltT
                                       39

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     In the interi.Ti, the City has  identified several unlined areas which need
to be filled to meet minimum slope requirements in WAC 173-304.  Additional
filling In these areas will be kept to the minimum required to meet the final
grade requirements of the Minimum  Functional Standards.  The City plans to
develop an unfilled area of the landfill (North Borrow Pit) for future waste
disposal.  Filling of this or other previously unused areas will require a
liner consistent with WAC 173-304.

     Should a variance be needed and granted, the Central Area Pit will be
brought up to final grade in accordance with the Operations and Closure Plan
to minimize leachate production.   Leachate head wells will be Installed in the
waste In the Central Area to assure that the leachate head requirements of MAC
173-304 are being met.  Ecology and EPA will identify and approve of the
appropriate number of leachate head wells during the Remedial Design phase.

     MFS requires operating landfills to submit an operating plan by October
1987.  A schedule for closure of the landfill under WAC 173-304 Is considered
part of the remedial action at this site.  The schedule, developed as part of
the required Operations and Closure Plan, will address various waste reduction
measures and develop contingency plans If these measures do not produce the
expected results.  The contingency plans will Include specific dates for
beginning the process to site another municipal solid waste disposal facility
to serve the City of Tacoma.  Haste reduction measures to be considered
Include, but are not limited to:

     o    Increased recycling Including a program to exclude hazardous waste
          from the landfill
                                       40

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      o    Incineration of the light fraction of shredded waste at the Tacoma
           City Light Cogeneraticn plant

      o    pyrolysls  of the heavy fraction of shredded waste at an on-s1te
           facility

      Several  utilities pass  through the site.   The  Operations  and Closure  Plan
will  provide  for  rerouting these utilities around  the site  or  developing a
testing and maintenance program  that will  ensure  their long-term  Integrity
without Interfering  with the  selected remedy.
                                             ^
      The production  of methane gas  at the  landfill  Is being addressed  through
the Installation of  a  gas  extraction system and  is  being monitored using a
series of gas  probes  Installed around the  landfill.   The gas collected by  the
extraction system 1s  burned by the  combusters. which meet PSAPCA's  BACT
requirements.  Any future  expansion  of  this  system  will be  required to comply
with  these requirements.   Additional  gas probes will  be Installed  In the
surrounding neighborhoods  to  verify  that the extraction system  Is preventing
off-site gas migration.   If significant concentrations of gas are found In the
soils off-site, further  gas extraction wells may have  to be  Installed to
collect and'control  these  methane sources.

     Because landfill  gas  Is  warmer  than the ambient  air. condensate collects
In the gas collection  line.   This condensate Is currently allowed to drain
back Into the  landfill   Condensate  from the flare station  Is collected and
discharged to  the sanitary sewer.  As part of the remedial  design, the
                                       41

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quantity and quality of these condensates will be determined.  If significant
concentrations or volume of condensates are found, the condensate shall be
collected and treated appropriately.  Source monitoring of the gas burners and
the treatment plant system will be required.

     Monitoring

     Ground water monitoring wells shall be Installed In locations appropriate,
for obtaining the following information:

     o    determine if the ground water extraction system Is preventing the
          spread of the contaminant plume

     o    determine the extent of plume migration to the east of the site

     o    Identify any potential Impacts to Leach  Creek and the Flrcrest well
          system

     o    ensure there Is no dense phase plume migrating away from the site In
          the deepest zones of the aquifer.

Ecology and EPA will review and approve of the number and location of the
groundwater monitoring wells during the Remedial Design phase of the cleanup
program.

     Leach Creek will be monitored for both water quality and quantity.  Other
surface waters acting as receiving waters for either the groundwater
                                       42

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 extraction  system or the surface drainage system will be monitored for water
 quality.  Effluent from the treatment system will also be monitored to assure
 that  discharge  limitations are not exceeded.  The nature and extent of the
 monitoring  program.  Including bloassays, will be developed during the Remedial
 Design phase  of the  cleanup program.

      At a minimum,  the  private wells  In  the  path of the plume will  continue  to
 be monitored  on  a  quarterly basis.   Flrcrest wells  will  be sampled  monthly.
 Any well, public or  private,  which  becomes  contaminated due to the  landfill
 will  be replaced and  water  will  be  supplied  from existing City of Taccma  water
 supply systems.  If  EPA  and Ecology make a determination  that any well  is  in
                                             \
 danger of exceeding  an MCL. or a  contaminant level  based  on an EPA  risk
 assessment,  connection  to  Tacoma's  municipal water  supply will  be required.
Aesthetic quality will also be a  consideration  In making  this determination.

     Tacoma,  In cooperation with  the  Town of Flrcrest,  and  Pierce County, will
pursue the establishment of an ordinance, or other  suitable  methodology,  to
restrict drilling of  water  supply wells  In an area  from Tyler Street  to Leach
Creek; and from Center Street  to approximately South  56th Street.

     B.  Statutory Determinations

     The selected remedy meets all  statutory requirements for  the overall
protection of human health and the  environment.  The  groundwater  extraction
system will  remove contaminated groundwater  migrating from  the  landfill and
prevent  contamination from spreading  In  the  aquifer.  The movement of
contamination to nearby Leach  Creek should be prevented by groundwater

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pumping.  Treatment of  the extracted water  will  be  designed  to  reduce the
toxlclty, mobility and  volume of  contaminants  and prevent  them  from returning
to the groundwater or surface water environment.  Nearby residents affected by
contaminated groundwater, or by low water volume or flow as  a result of the
operation of the extraction-treatment  system,  will  be  connected  to Tacoma's
municipal water system.

     The selected remedy must also meet all Applicable or  Relevant and
Appropriate Requirements (ARARs)  and should address those  items  listed In the
To Be Considered category.  These are  listed and their application Is briefly
described In Attachment A.

     The laws and regulations of  concern include but are not limited to the
following:

     1.   Resource Conservation and Recovery Act (RCRA; 42 USC 6901), RCRA
          regulations (40 CFR 261 to 280).  Washington  State  Dangerous Haste
          Regulations (MAC 173-303 and 70.105  RCW).  and Washington State
          Minimal Functional Standards for  Solid Haste Handling  (HAC 173-304
          and 70.95 RCH).

               Groundwater protection  requirements  of  RCRA and Hashlngton
               State Dangerous Haste Regulations will  be attained by
               Installation of the landfill cap  to  minimize  leachate
               production, and operation of the groundwater  extraction wells
               to remove contaminated  groundwater.   The selected remedy
               prevents further spread of groundwater  contamination and
                                       44

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          constitutes a Corrective Action Program  as  specified  in 40 CFR
          264.100 and MAC 173-303-645(11).  Closure of  the  Tacoma
          Landfill to State Minimum Functional Standards will be
          evaluated to ensure consistency with RCRA landfill closure
          standards.
2.   Safe Drinking Water Act (42 USC 300). and Primary Drinking Hater
     Standards (40 CFR 141).

          Groundwater will  meet maximum contamination levels (MCLs) and
                                       N
          appropriate health-based standards as the contaminated plume Is
          removed and leachate generation Is minimized.   The selected
          remedy will prevent exposing the public to contaminated
          drinking water by monitoring residential wells for MCLs and
          connecting the house to Tacoma's municipal water supply when
          conditions require It.   Any affected public water supplies also
          will  be connected to dty water.  Therefore,  by monitoring,
          providing an alternate  drinking water supply,  and restricting
          groundwater use (until  the aquifer no longer  exceeds  these
          levels) In the area,  the selected remedy will  meet the
          requirements of these regulations.
                                  45

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3.   C'.ean Air Act  (72  USC  7401).

          If an airstrlpping  system  is  used,  concentrations  of
          contaminants  in the  air  stripper  off-gases  will  be required  to
          meet the  requirements of the  Clean  Air  Act.   The flares for  the
          methane gas extraction system must  also.meet  the requirements
          of the Clean  Air  Act.
4.   Clean Water .Act  (33  USC  1251),  National  Pollution  Discharge
     Elimination System  (NPOES;  40 CFR  122).  NPDES  Permit  Program (HAC
     173-220), and  Water  Pollution Control Act  (RCW 90-48).

          The selected remedy  treats  the  extracted  water to meet MCLs,
          health-based standards, or  Hater Quality  Criteria prior to
          discharge.  Therefore,  there  will  be  no adverse  Impact on
          surface waters  resulting from discharge of treated  groundwater,
          and the requirements of these regulations will be attained.
          The landfill cap will  reduce  leachate generation and  therefore
          reduce the  Impact on groundwater.   Storm  drainage will be
          collected and  discharged either to existing storm sewers or to
          surface waters.  Contaminated storm water runoff will meet
          pre-treatment  regulations  and will  be discharged to the
          sanitary  sewer.  Groundwater  extraction and treatment will
          further reduce  the  contaminant  plume. Other  substantive
          aspects of  the  NPOES Permit System will be met during the
          design phase,  although  no  permit  is actually  required.
                                   46

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           Although on-site remedial  work does not require a permit,  the
           substantive  requirements  of any applicable permit will  be  met.
           Federal,  state,  or  local  permits which are required for
           off-site  activities  will  be obtained.
5.   Rules  and Regulations of  the  State  Board  of  Health  Regarding  Public
     Water  Systems  (MAC 248-54).

          The selected remedy  provides standards  for  connection to an
          alternative drinking water supply for all residents who  require
                                       \
          these supplies In conformance  with these regulations.
6.   Protection of Withdrawal Facilities Associated with Groundwater
     Rights (WAC 173-150).

          This regulation protects water rights both In terms of water
          quality and quantity.   Groundwater quality will reach levels
          less than MCLs; therefore the selected remedy complies with
          that portion of the regulation.  The other portion of the
          regulation requires that surrounding wells not be deprived of
          their water supply due to other groundwater removal actions.
          Alternative water supplies will be made available to all
          residents affected by  groundwater removal actions to meet the
          requirements of this regulation.
                                  47

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     7.   Minimum Functional Standards for Landfills (HAC 173-314 and 70.95
          RCW).

               The technology to be applied to remediate the landfill at a
               minimum will meet the Washington state standards for ongoing
               landfill operations, closure, capping, leachate containment,
               and methane control.
     8.   Hazardous Haste Cleanup Act (70.1058 RCW).
                                           \
               The selected remedy will be the cleanup standards established
               by this act.

     The selected remedy meets the SARA preference for permanent solutions to
the maximum extent practicable.  Treatment technologies are used as a
principal element of the remedy and they will effectively reduce the toxlclty,
mobility, and volume of the contaminants permanently.  Connection of
residents, as required, to the Tacoma municipal water water supply Is also
considered a long-term solution.
                                                            *
     The selected remedy meets all objectives of remedial action 1n that It
provides a safe water supply and therefore protects public health, provides a
permanent solution with moderately frequent maintenance, protects the
environment to the maximum extent practicable, and reduces toxlclty, mobility,
or volume as a principle element of treatment.  The selected remedy meets the
requirement of cost-effectiveness.
                                       48

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VII.       ENFORCEMENT
     On June  27,  1986,  Tacoma  assumed responsibility for conducting  the RI/FS
under a Response  Order  on  Consent  Issued by Ecology.   The-remedial action  Is
anticipated to  be accomplished voluntarily by the  responsible  parties.  EPA
and Ecology Intend to start  a  negotiation period after the  signing of the
Record of Decision and  will  ensure  that  the remedial  action  proceeds.
Finally, EPA  and  Ecology are still  considering  the  possibility of Identifying
additional parties  who  may be  potentially responsible  for  conditions at the
site.   Other  than  the June 27,  1986 Consent Order,  there has never been any
enforcement action  taken by  the  regulatory agencies  (I.e., EPA or Ecology)
regarding the Tacoma Landfill  site.   If  the responsible  parties decline to
Implement the selected  remedy  as described in the Record of Decision, however,
EPA and Ecology will seek  appropriate  enforcement action.
                                       49

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VIII      COMITY RELATIONS
     Community relations activities conducted at the Tacoma Landfill  site  to
date Include the following:

     o    In 1983. the Taccma landfill  was included  as  part of  the South
          Tacoma Channel site on the National  Priorities  List under
          Comprehensive Environmental  Response.  Compensation, and Liability
          Act of 1980 (CERCLA).

     o    In Hay 1985. Ecology and Black & Veatch began Remedial Investigation
          (RI) Phase I.

     o    In December 1985, Ecology and Black &  Veatch  began Implementing  thu
          RI Project Work Plan and Sampling Plan Phase  I.

     o    In 1985, a community relations plan was developed by  Black  & Veatch
          and Hall and Associates for  Ecology.

     o    From May 1985 to the present, the City of  Tacoma  maintained
          correspondence with Interested local residents  and well owners by
          providing notification of quarterly sampling  and  outlining
          analytical results.

     o    In May 1986. the City of Tacoma Issued a fact sheet discussing
          management of methane gas at the landfill.
                                       50

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 o    On May 13. 1986, U.S. EPA, In cooperation with the City of Tacoma
      and Ecology,  conducted a public meeting to discuss well water
      quality of private wells surrounding the landfill.

 o    In July 1936.  the City of Tacoma issued a press release and  letter
      to residents  discussing background and scope of the RI.

 o    In July 1986.  the City of Tacoma and Ecology signed a consent
      agreement  establishing guidelines  for the  RI/FS.

 o    In  August  1986,  the City of Tacoma began sampling  13  private wells
      located  near  the landfill.

 o     In  February 1987.  the Phase I  Sampling  Plan,  Phase II Sampling Plan
      and. Phase  I RI  Report were  completed and made available to the
      public  through  Taccma City  and County libraries.

 o    On April 16,  1987,  Ecology,  In cooperation with the City of Tacoma
      and EPA  ,  conducted a public meeting and provided  a fact sheet
     discussing progress of the  RI/FS.

o     In January. 1988 a  public notice was  published  in  the  Tacoma News
     Tribune announcing  the availability  of  the RI and  FS  Reports and a
     public meeting  to be  held February 11.  1988.
                                  51

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o    On February  11,1988, Ecology,  in cooperation  with  EPA and  the City
     of Tacoma, conducted a public  meeting  to  discuss alternatives for
     cleaning up  the groundwater and controlling methane gas at the
     landfill. Including the agencies'-preferred plan.

o    From February 4 through March  4. 1988,  public comments on  the RI/FS
     were accepted and documented.

o    In February  and March  1988 the the Responsiveness  Summary  and Record
     of Decision  were written.
                                   52

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                                  APPENDIX A
              APPLICABLE OR RELEVANT AND APPROPRIATE REPEKXTS
A.   FEDERAL LAWS AND REGULATIONS
                   \

     o    Resource Conservation and Recovery Act (RCRA) (42 USC  6901),
          Subtitle C:

                                          \
              Protection of groundwater (40 CFR 264,  Subpart  F) Closure and

              post-closure of landfills (40 CFR 264.  Subpart  G) [Note:  These

              are administered by Ecology under Dangerous  Haste Regulations,
              HAC 173-303]


     o    Safe Drinking Hater Act (SWOH) (42  USC 300):


              Drinking Hater Standards  (40 CFR  141).   Enforceable Maximum

              Contaminant Levels (MCLs),  Hhlch  are  relevant and appropriate
              at this site.   [NOTE:  This  Is  administered by the Department of
              Social  and Health  Services  under  HAC  248-54-175 for public

              water supplies]


     o   Clean Hater Act (CHA)  (33 USC  1251):


              national  Pollutant Discharge Elimination System (NPOES)  (40  CFR

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          122)  [Note: NPDES program  is administered by Ecology under WAC
          1-73-220]


          Hater Quality Criteria (EPA440/5-86-001).
o    Clean Air Act  (CAA) (72 USC 7401):


          National  Emission Standards for Hazardous Air Pollutants

          (NESHAPS)  [Mote:  NESHAPS Program is administered by Ecology

          and Puget  Sound Air Pollution Control Agency under MAC 173-403].
                                      \4

O    OSHA 29 CFR  1910:


          governs worker safety at hazardous waste sites

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B.   WASHINGTON STATE LAWS AND REGULATIONS





     o    Dangerous Haste Regulations, MAC 173-303:  established  standards for


          handling and disposal  of hazardous waste.





     o    Minimum Functional  Standards for Solid Haste Handling,  70.95 RCW and


          HAC 173-304:  requirements for  operation  and closure of solid waste


          disposal  facilities.





     o    Hazardous  Waste  Cleanup,  Chapter 70.1058  RCW:   standards for the


          cleanup of hazardous waste s1tes.x





     o    Hater Quality Standards  for  Waters of  the State of Hashlngton,  HAC


          173-201:   Standards for  discharge  to Flett Creek, or Leach Creek,  or
                         -» •                • •
                                          •V "    •

          surface waters of the  state.





     o    Submission  of Plans and  Reports  for Construction of Hastewater


          Facilities,  WAC  173-240:   standards for the design, operation and
                         /

          maintenance  of waste water treatment systems.





     o    National Pollutant Discharge Elimination System Permit  Program,  HAC


          173-220:  Discharge limitations  If treated water Is discharged  Into


          surface waters.





     o    Underground  Injection Control Program,  WAC 173-218:  discharge


          standards for reinjectlon of treated water Into the ground.

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o    State Haste Discharge Permit Program, WAC 173-216:  Standards for
     the discharge to the sanitary sewer or groundwater (except by
     Injection).

o    Hashlngton Clear Air Act, RCH 70.94: applicable for discharging
     pollutants Into the atmosphere from a new source.

o    General Regulations for Air Pollution Sources, WAC 173-400.

o    Implementation of Regulations for Air Contaminant Sources, WAC
     173-403. '

o    Emission Standards and Controls for Sources  Emitting Volatile
     Organic Compounds. HAC 173-490.

o    Instream Resources Protection Program - Chambers-Clover Creeks
     Basin, HAC 173-512:  governs minimum water flow and levels
     requirements.

o    Protection Associated with Groundwater Rights, WAC 173-150-100:
     applicable to activities that would degrade  water quality.

o    Minimum Standards for Construction and Maintenance of Hater Hells,
     WAC 173-160:  governs design of extraction and monitoring wells.

o    Water Hell Construction Act, RCH 18.104:  provides for the
     regulation of water well construction.

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o    Hater Pollution Control Act, RCH 90.48:   standards  for the
     protection of surface water and groundwater.

o    Management of Haters of the State. RCW 90.54.020:  provides for the
     protection of state water quality.

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TO BE CONSIDERED


     o    Ecology New Source  Review Guidelines  for Toxic Air Contaminants  In
          the  State  of Washington,  September  1986.


     o    EPA  Policy Statement  -  Groundwater  Protection  Strategy.


     o    Washington Department of  Ecology  Final Cleanup Policy:   (Technical
          memorandum dated July 10,  1984) used  for  guidance  In establishing
          cleanup  levels.

                                         V
     0    State Hater  Code. RCH 90.03 and Hater Rights.  RCH  90.14:  estab-
          lishes water  rights permits necessary for water withdrawals.
          Including  groundwater extraction.


     o    State Environmental  Policy Act (SEPA). HAC 197-11:  covers all
          actions which may have  significant environmental Impact.


     o    State Protection of Upper Aquifer Zones.  HAC 173-154:   restricts
          activities that would Impair senior groundwater rights. Including
          water level  lowering, and water quality degradation.


    o     Protection of HUMrawal Facilities  Associated  with Groundwater
          Rights,  WAC  173-150:  restricts activities that would  Impair senior
          groundwater rights.  Including  water  levels lowering and water
          qualIty degradation.

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o    City of Tacoma Code, Chapter 12.08:  pre-treatment regulations whicl:
     govern 'discharge to the sanitary sewer.

o    Pierce County Storm Drainage Ordinance 86-60:  provides guidelines
     for the report criteria, analysis and design of public and private
     storm drainage systems.

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                                    APPENDIX 8
                              RESPONSIVENESS SUMMARY
     This community relations  responsiveness  summary  Is  divided  Into the
following sections:
Section 1.0    Overview.  This section reviews  the U.S.   Environmental
               Protection Agency s (EPA) preferred alternative for corrective
               action, and likely public reaction to  this alternative.
Section 2.0
Background on Community Involvement and Concerns.  This section
provides a brief history of community  Interest and concerns
raised during remedial planning activities at the Tacoma
Landfill site.
Section 3.0
Summary of Major Comments Received During the Public Comment
Period and Agency Responses to the Comments.  Both written and
oral comments are categorized by relevant topics.  EPA's
responses to these major comments are also provided.

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Section 4.0    Remaining Concerns.  This section describes remaining community
               concerns that EPA and Ecology should consider  in conducting  tn|
               remedial design and remedial action at  the Tacoma Landfill site.

     Community relations activities conducted during remedial response
activities at the Taccma Landfill site are listed In Attachment A to this
summary.

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                                  1.0   OVERVIEW
      The  City of Tacoma,  under a Response Order on Consent Issued by the
 Washington  State Department of Ecology, completed a Remedial
 Investigation/Feasibility Study (RI/FS) for the Tacoma Landfill  site,  located
 south of  Tacoma, Washington.   From 1960 through the 1980s, the landfill has
 received  refuse  and  garbage from the  city's collection service.   Hazardous
 materials were part  of  the refuse.  Contaminants were discovered In  nearby
 drinking  water wells at levels high enough to cause public health concerns.
 The cleanup alternative recommended by Ecology to EPA, was to Intercept the
 advance of contaminants by extracting the contaminated water, treating It. and
 discharging the  cleaned water.   This  alternative Is described In more detail
 In the Feasibility Study  (Chapter  4;  Black & Veatch 1987)  and In the Selected
 Remedial Alternative section  of the Record of Decision (Section  VI).

     In this  summary, concerns  of  the local  community about problems at the
 site, the recommended cleanup alternative, and the  study process  Itself are
 described.  Public comment also Indicates  that residents hope the  cleanup will
 be as quick and  thorough  as possible,  and  not raise  additional problems
 through Its Implementation.   Only one potentially responsible party, the City
of Tacooa. has been  Identified  to date  although  an  Investigation  to Identify
others has been  Initiated.  The  Identified responsible parties will share
 cleanup costs.   Residents  are  concerned about  the funding  to  perform the
 cleanup and any  adverse  Impact  upon refuse collection  rates.

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        2.0 BACKGROUND ON COMMUNITY INVOLVEMENT AND CONCERNS
     Community Interest in the  Tacoma  Landfill began as early as 1968 when
local residents complained of poor  water quality In thel.r private wells.   This
condition continued throughout  the  1970s.  The residents are currently
concerned about leachate  from the landfill contaminating their private wells,
and methane gas entering  their  homes.

     Early In the  Remedial  Investigation/Feasibility Study (RI/FS)  process
(1985),  Hall  and Associates  Interviewed local residents and government
officials and compiled  a  list of community concerns regarding the landfill.
The following Is a compilation  of community concerns In 1985:

     o    Lack of  Interest and  unwillingness to provide water testing  by  the
          public health agency.

     o    Lack of  candor  by government officials,  particularly relating to
          contamination of wells In University Place during the  late  1970s.

     o    Quality  of drinking water.

     o    Health of small  children In the  neighborhood  and  recent miscarriages.

     o    Cost of  replacing private  wells  and connecting  residences to the
          city's water  system.

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     o    Inconvenience  associated with using  bottled water

     o    Need to be kept  informed of  landfill  related activities.

     The City of Tacoma  and  Ecology developed  a community relations plan  In an
effort to keep the public  Informed of  RI/FS activities.  The City of Tacoma
has addressed public concerns  by  holding meetings with residents to discuss
RI/FS activities and public  health concerns.   Attachment A summarizes the
community relations activities  conducted at the South Tacoma Landfill.  The
following is a record of those  activities:
                   •                      ^
     1)   In 1968, the City  of  Tacoma  Department of Public Works began
receiving complaints of  contamination-of the Home Builder's Association well,
located at South 40th and  Orchard Streets.

     Actions;  The City of Tacoma  conducted a chemical analysis of the well
     water.  Results revealed  the water contained a high Iron content, was
     discolored, and had a slight odor.  The city Installed a leachate
     collection  system comprised  of a  gravel drain and dike.  The dike
     diverted leachate flow  to  the drain that  discharged to a perforated
     manhole connected to the  city sewer system.  An additional cover placed
     over the fill promoted  surface water  drainage, Inhibited Infiltration of
     water, and  reduced  leachate  production.   The Home Builder's Association
     was eventually connected  to  the  city's water system.

     2)   In the late  1970s, wells owned by the University Place Water Company
located west of  the  landfill,  were found to contain elevated levels of Iron
and manganese.   Residents complained  of unappealing water taste, color, and
odor-

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      Actions:  An Investigation conducted by Ecology Indicated that well
      water  contamination  could have resulted from surface  water  or groundwater
      froo the  landfill, or  from water migration through  material  containing
      high levels of  Iron  and  manganese.   Residents served  by  these  wells  were
      eventually  connected to  the  city's  water  system and these wells have  not
      yet been  abandoned in  accordance with  State requirements.
     3)   In 1985, prior  to  the  RI,  groundwater  samples were collected from
wells near the landfill and  analyzed for U.S.  EPA  priority pollutant volatile
organic compounds.  Four  private wells  located In the vicinity of the landfill
were found to contain priority pollutant volatile organic compounds.

     Actions:  In June  1985,  vinyl  chloride  was detected In the
     Shaughnessy1s well and  they were connected  to  the city's water system.
     Vinyl chloride was detected In  the Donaldson's well and they were
     connected to the city's water system In June 1986.  Although vinyl
     chloride was not detected In the remaining  two wells (those of the
     Hlgglns/Knlpher and Miller residences), the city supplied these
     residences with bottled water for drinking.   The Hlgglns/Knlpher and
     Miller residences were  later connected to the city's  water system In
     October and December 1986. respectively.  In 1987, the Meyer and Phillips
     residences were connected to the city's water system because vinyl
     chloride contaminated their wells.

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     4)   Early in 1986, local citizens were becoming concerned about the
quality of water from their private wells.
                i
     Actions: Ecology. In cooperation with the City of Tacoma and EPA.
     conducted a public meeting on May 13. 1986 to discuss affects of
     potential leachate migration to private wells.  The meeting was open
     exclusively to private well owners.   Twenty citizens and ten city, state,
     and federal representatives attended.  At this time, Black & Veatch was
     still acting as a consultant for Ecology.  A description and history of
     the site was outlined, the affects of methane gas migration were
     discussed, and an _,enda and fact sheet were distributed.
     5)   In May 1986. local residents voiced concern about lateral methane
gas migration at the City of Tacoma municipal landfill.

     Actions:  The  city hired a consultant (Mandeville Associates)  to
     Investigate gas production and the extent of off-site migration prior to
     the release Incident.  The city conducted field surveys using portable
     exploslmeters and found methane gas had migrated beyond the landfill
     boundaries.  As a result of these findings, a gas extraction system
     comprised of  128 gas extraction wells with gas probes at 66 locations was
     Installed.  Initial efforts focused on controlling gas In businesses
     located southwest of the site.  A flare static- with permanent flares was
     Installed  In  November  1986.  The city Implemented a gas monitoring
     program for structures surrounding the landfill.  Both ambient and point
     sources were  measured.

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     6)   As  early  as  1983.  local  residents were voicing concerns about
potential groundwater  contamination from leachate migrating from the landfill.

     Actions:   In  June  1986,  the City of Tacoma, under the direction of
     Ecology,  assumed  responsibility for conducting an  RI/FS.  Quarterly
     groundwater monitoring  activities  were established  to  Identify hazardous
     contaminants.   The  city continued  contact  with specific residents by
     notifying them  of sampling  dates and  reporting analytical results.
     Public Involvement  in landfill  Issues  Is maintained  by Ecology  conducting
     public meetings and  providing  fact sheets  on  recent  landfill activities
     and studies.

     7)   As the RI  progressed  in 1987.  local citizens continued  to  voice
concerns and questions.

     Actions:   Ecology, In cooperation with  the  City of Tacoma  and EPA,
     conducted a public meeting on April 16. 1987  to discuss the  progress of
     the RI/FS.  Groundwater well monitoring procedures and analytic results
     were addressed.  At  that time,  three to four  residences had been
     connected to the city's water supply.  Methane gas migration and
     monitoring were discussed.  Or. Branchflower,  a consultant to the City of
     Tacoma, discussed risk assessment at the landfill site.  Black & Veatch.
     acting as consultants to the city,  provided graphical representation of
     well locations and migration pathways.  An agenda and fact sheet were
     distributed.

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     8)   After the RI/FS was made public  in  February  1988,  citizens had
concerns and unanswered questions.

          Actions;  On February  11.  1988.  Ecology,  In cooperation  with  EPA
          and the City of Tacoma, conducted a public meeting to discuss
          remedial alternatives for cleaning  up  leachate  and methane gas at
          the landfill.  Questions relating to the  RI/FS  were answered and
          public comments were  recorded.

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            3.0 SUMMARY OF MAJOR COMMENTS RECEIVED DURING THE PUBLIC
          COMMENT PERIOD AND AGENCY RESPONSES TO THE COMMENTS

     The public comment period was  open  from February  4 through  March 4,
 1988.  Ecology held a public  meeting  In  Tacoma  on  February 11,  1988  to explain
 the study and the remedial  alternatives.   Formal comments "received at that
 meeting concerned providing an alternate  water  supply,  coordinating  planning,
 evaluating alternative design options, and  Implementing new  landfill
 operations Including recycling and  ash disposal.   The  last comment Is
 considered beyond the scope of the  FS.
                                           \
     Comments from members  of the public,  primarily  Tacoma area  residents,
 regarding the FS  report are summarized below.   Questions were addressed to
U.S. EPA, Ecology,  the Tacoma-Plerce County Health Department (TPCHO). and
City of Tacoma representatives and  their  consultants.
FORMAL COMMENTS

     Four participants  from  the public presented formal comments during the
public hearing.   Those  comments are summarized below.

     1) Provision of  an  alternative water supply for residents whose wells
have been contaminated  regardless of the chosen alternative was a concern of
one participant.

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     Response:  The preferred alternative  includes provision of an
     alternate, unthreatened  water  supply  (municipal  water)  to any  resident
     whose water supply  is  adversely  impacted  as  further  describes  in the ROD
     by contamination  emanating  from  the  landfill.
     2) One comment addressed  the  need  to  incorporate  long-term planning in
future studies.  The  speaker noted that seven years  ago.  many of today's
problems connected with  the  landfill  were  not known  and not planned for.
Another comment addressed  the  need for  more  coordination  in the planning
process between the consultants  and agencies connected with landfill studies.
                      ,                     \

     Response;  Long term planning of the  landfill operation is conducted at
                                                           •"t"i<
     the local level  with  assistance and review  by  the state.  Selection of
     the preferred alternative under CERCLA/SARA Included analysis of
     long-term needs.   Long-term planning  Is part of the  studies.  Ecology a<
     EPA agree that more coordination Is needed  and  have  Incorporated this
     Into ongoing community  relation activities.
     3) Several  design options  were  offered  by one  participant who felt that
they should  have been  considered  during  the  evaluation  of  remedial
alternatives.   These options  are  as  follows:

   o  An  aeration facility to remove volatile material  from the groundwater.

   o  A system of wells completely encircling the landfill  to  Intercept and
      retrieve contaminated groundwater.

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   o   Incorporation of removable  pumps  and  sequencing pumping to optimize
       groundwater retrieval.

   o   Discharge  of treated  groundwater  to the  Simpson pulp  mill  or  other use
       of  treated groundwater  as a water  supply.

   o   Use of extracted methane to produce electricity.  '

          Response;  Ecology and  EPA will take  note of these suggestions and
          they will  be evaluated during  the Remedial  Design phase as
          appropriate.
     4) A comment was received concerning the potential threat to public
health caused by heat generation from spontaneous combustion of materials In
the proposed sealed landfill.  Such conditions might lead to an explosion that
would endanger nearby apartments and their Inhabitants, and taxpayers would be
obligated to pay for the damage.

     Response;   The  landfill  will  be  continuously  monitored  so  that
     spontaneous combustion problems should not occur.   Should  a problem
     occur, the landfill has a contingency plan and an  emergency response plan
     In plact.

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