United States
           Environmental Protection
           Agency     '
             Office of
             Emergency and
             Remedial Response
EPA/ROO/R08-90/027
November 1969
SEPA
Superfund
Record  of  Decision
           East Helena, MT

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50272-101
 REPORT DOCUMENTATION
        PAGE
1. REPORT Mtt
 EPA/ROD/R08-90/027
                                           3. n»clpfcnf« Acce**ton Mo.
 4. TMoendSubM*
   SUPERFUND RECORD OF DECISION
   East Helena, MT
   First Remedial Action  	
                                           S. Report Dett
                                             11/22/89
 7. Authors)
                                           *. Performing OrgmizMlon Rept No.
 9. Performing Org*Jnia»on N«r»
                                           10. ProttcVTMfc/Wort Unit No.
                                                                    11. Conlnc«(C) or C**nt(G) No.

                                                                    (C)

                                                                    (Q)
 12. &Don*ortngOrg*fllalionN*n»endAddreM
   U.S. Environmental Protection Agency
   401 M Street,  S.W.
   Washington,.  D.C.  20460
                                           13. Type ol Report k Period Covered

                                               800/000
                                                                    14.
 15. Supptemenury Notee
 18. Abstract (Limit: 200 word*)
 The  80-acre East Helena site, in  East Helena, Lewis and Clark  County, Montana,  is a
 primary lead smelting facility that has been in  operation since 1888.   In  1927  the
 Anaconda Company constructed a plant adjacent to the lead smelter to recover zinc from
 the  smelter's waste  slag.  Asarco,  the owner and operator of the smelter  facility,
 purchased the zinc plant in 1972  and operated the plant until  1982.  Prickly Pear Creek
 flows  near the site  and has been  found to contain elevated  levels of arsenic and lead.
 Air  quality and soil investigations also revealed the presence of contaminated soil  in
 East Helena residential areas, contaminated process ponds over shallow  ground water  nea
 the  plant,  and elevated blood-lead levels in school children.   A 1984 remedial
 investigation identified elevated levels of metal contamination in soil,  livestock,
 plants,  and ground and surface waters with the sources of onsite contamination  being
 primary and fugitive emissions and seepage from  process ponds  and process  fluid
 circuitry.   The site has been segregated into five operable units, consisting of the
 process ponds, the ground water,  the surface water, the slag pile, and  the ore storage
 areas.   This ROD addresses four process fluid ponds which are  used for  process  water
 retention and include the Lower Lake, the speiss granulating pond and pit,  the acid  plant
 water  treatment facility, and the former Thornock^I*ake® naw dry.  The primary
 contaminants of conce.r^i:^f£h«f,,t&!*e5&aS^ i|$fl|^9riil^4?alf'. 'including arsenic  and lead.
 (Continued on next page) ° ^'
         &68»H VBH^SW^al^ Deluding
           «tefiW            ro p-^a
  17. Document Aneiysls «. Descriptor*
    Record  of  Decision -  East
    First Remedial Action
    Contaminated Media:   soil,  sediment,
    Key Contaminants:  metals (arsenic,  lead)

    b. MentffienVOpen-Ended Term*
    c. COSATl Field/Group
  18. Availability Statement
                            19. Security CU»* (Thit Report)
                                   None
                                                     20. Security Clu* (Thl* P*ge)
                                                            None	
21. No. ofPige*
     185
                                                                                22. Price
 (See ANSI-Z39.18)
                                      See /iwtructfon* on Remrw
                                                      OPTIONAL FORM 272 (4-77)
                                                      (Formerly NT1S-35)
                                                      Department ol Commerce

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EPA/ROD/R08-90/027          .
East Helena, MT

16.  Abstract  (Continued)

Whe selected remedial action  for this site includes excavating and smelting  55,150 cubic
yards of soil  and/or sediment  from all four process ponds and multi-media monitoring
after individual remedial activities are implemented at three of the process pond areas.
Process pond remediation activites include replacing the speiss granulating  pond with a
tank and a secondary containment facility and replacing the pit with a  lined facility;
replacing the  settling system at the acid plant water treatment facility with  a closed
circuit filtration treatment  system; in-situ co-precipitation of the process wastes from
the Lower Lake, replacing the  Lower Lake with two steel tanks to contain process wastes,
and constructing a lined pond for emergency containment of storm runoff.  If pilot-scale
testing of in-situ co-precipitation proves to be impractical, a contingency  plan will be
implemented, which includes treatment of Thornock Lake water at an onsite water
treatment facility to removal  metals, followed by discharge to a POTW.  The  estimated
present worth  cost for this remedy is $9,644,500 which includes an annual O&M  cost of
$611,200.

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CONTENTS
                                                       Page
RECORD OF DECISION DECLARATION                             1
RECORD OF DECISION SUMMARY                            x 1-1
     1    Description of Site                            1-1
     2    Site History and Enforcement  Activities        2-1
          2.1  Smelter Operations                       2-1
          2.2  Environmental Investigations              2-1
          2.3  Blood-Lead Studies                       2-3
          2.4  Superfund Investigation  Work  and
               Enforcement Activities                   2-4
     3    Community Relations Activities                3-1
     4    Scope and Role of Response Actions            4-1
          4.1  Operable Unit Identification              4-1
               4.1.1  Process Ponds and Fluids          4-2
               4.1.2  Groundwater                       4-3
               4.1.3  Surface Water, Soils,  Vegetation,
                      Livestock,  Fish,  and Wildlife     4-3
               4.1.4  Slag Pile                         4-3
               4.1.5  Ore Storage Areas                 4-4
          4.2  Response Actions                         4-4
     5    Summary of Site Characteristics               5-1
          5.1  Contamination Sources                     5-1
               5.1.1  Lower Lake                         5-5
                                                    • ,  •
                                                    -  : -WD
                                                      '• /I~W

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CONTENTS (Continue^/

                                                       Page

               5.1.2   Speiss Granulating Pond and Pit    5-5

               5.1.3   Acid Plant Water Treatment
                      Facility                           5-6

               5.1.4   Former Thornock Lake               5-7

     6     Summary of Site Risks                          6-1

          6.1   Human Health Risks                        6-1

               6.1.1   Contaminant Identification         6-1

               6.1.2   Exposure Assessment                6-2

               6.1.3   Toxicity Assessment                6-9

               6.1.4   Risk Characterization
                      Information                       6-12

          6.2   Environmental Risks                      6-13

          6.3   Conclusions                              6-15

     7     Description  of Alternatives                    7-1

          7.1   Alternatives for Lower Lake               7-5

               7.1.1   No Action                          7-6

               7.1.2   Alternative 4A                     7-6

               7.1.3   Alternative 4B                    7-14

               7.1.4   Alternative 4D                    7-14

               7.1.5   Alternative 4E                    7-15

               7.1.6   Alternative 5S                    7-16

               7.1.7   Applicable or Relevant  and
                      Appropriate Requirements  (ARARs)
                      and Sediment Cleanup Objectives
                      for Lower Lake Alternatives       7-19
                            iii

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CONTENTS (Cont inu«

                                                       Page

          7.2   Alternatives  for  the Speiss Granulating
               Pond  and  Pit                             7-21

               7.2.1  No Action                         7-21

               7.2.2  Alternative 8B+7E                 7-22

               7.2.3  Alternative 8B+7H                 7-26

               7.2.4  Applicable or Relevant and
                     Appropriate Requirements  (ARARs)
                     and Soil Cleanup Objectives for
                     Speiss Granulating Pond and Pit
                     Alternatives                      7-27

          7.3   Alternatives  for  the Acid Plant  Water
               Treatment Facility                       7-27

               7.3.1  No Action          •              7-28

               7.3.2  Alternative 11F                   7-28

               7.3.3  Alternative 11D                   7-30

               7.3.4  Alternative HE                   7-31

               7.3.5  Applicable or Relevant and
                     Appropriate Requirements  (ARARs)
                     and Soil Cleanup Objectives for
                     Acid Plant Water Treatment
                     Facility Alternatives             7-32

         7.4   Alternatives  for  Former Thornock Lake    7-33

               7.4.1  No Action                         7-33

               7.4.2  Alternative 14                    7-33

               7.4.3  Applicable or Relevant and
                     Appropriate Requirements  (ARARs)
                     and Sediment Cleanup Objectives
                     For Former Thornock Lake
                     Alternatives                      7-34
                             iv

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CONTENTS (Continued)

                                                       Page

     8    Alternatives Comparative Analyses              8-1

          8.1   Lover Lake                                8-2

               8.1.1  Protectiveness, Short- and
                     Long-Term Effectiveness, and
                     Permanence                         8-2

               8.1.2  Applicable or Relevant and
                     Appropriate Requirements (ARARs)   8-4

               8.1.3  Reduction of Toxicity, Mobility,
                     and Volume                         8-5

               8.1.4  Implementability                   8-6

               8.1.5  Costs                              8-6

               8.1.6  Lower Lake Alternatives
                     Evaluation Summary                 8-7

          8.2   Speiss Granulating Pond and Pit           8-7

               8.2.1  Protectiveness, Short- and
                     Long-Term Effectiveness, and
                     Permanence                         8-7

               8.2.2  Applicable or Relevant and
                     Appropriate Requirements (ARARs)   8-8

               8.2.3  Reduction of Toxicity, Mobility,
                     and Volume                         8-8

               8.2.4  Implementability                   8-9

               8.2.5  Costs                              8-9

               8.2.6  Speiss Granulating  Pond and Pit
                     Alternatives Evaluation Summary    8-9

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CONTENTS (Continue

                                                       Page

          8.3  Acid Plant Water Treatment Facility      8-10

               8.3.1  Protectiveness, Short- and
                      Long-Term Effectiveness and
                      Permanence                        8-10

               8.3.2  Applicable  or Relevant and
                      Appropriate Requirements  (ARARs)  8-11

               8.3.3  Reduction of Toxicity, Mobility,
                      and Volume                        8-12

               8.3.4  Implementability                  8-13

               8.3.5  Costs                             8-14

               8.3.6  Acid Plant  Water Treatment
                      Facility Alternatives
                      Evaluation  Summary                8-14

          8.4  Former  Thornock Lake                     8-15

               8.4.1  Protectiveness, Short- and
                      Long-Term Effectiveness,  and
                      Permanence                        8-15

               8.4.2  Applicable  or Relevant and
                      Appropriate Requirements  (ARARs)  8-15

               8.4.3  Reduction of Toxicity, Mobility,
                      and Volume                        8-16

               8.4.4  Implementability                  8-16

               8.4.5  Costs                             8-17

               8.4.6  State  and Community Acceptance   8-17

               8.4.7  Former Thornock Lake  Alternatives
                      Evaluation  Summary                8-17

          8.5  Alternatives  Evaluation  Process  Summary 8-17
                             vi

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CONTENTS (Continue  ,

                                                       Page

     9    The  Selected Remedy                            9-1

          9.1   Lower Lake                .                9-1

          9.2   Speiss Granulating Pond and Pit           9-4

          9.3   Acid Plant Water Treatment Facility       9-5

          9.4   Former Thornock Lake                      9-6

          9.5   Performance Requirements                  9-7

          9.6   Changes During Remedial Design            9-9

     10    Statutory Determinations                       10-1

          10.1  Protection of Human Health and the
               Environment                               10-2

               10.1.1  Lower Lake                        10-2

               10.1.2  Speiss Granulating Pond  and  Pit   10-3

               10.1.3  Acid Plant Water Treatment
                      Facility                          10-4

               10.1.4  Former Thornock Lake              10-4

          10.2  Compliance With Applicable or Relevant
               and Appropriate Requirements  (ARARs)      10-4

               10.2.1  Waivers and Prescribed
                      Standards                         10-5

          10.3  Cost-Effectiveness                       10-23

               10.3.1  Lower Lake                       10-23

               10.3.2  Speiss Granulating Pond  and  Pit  10-25

               10.3.3  Acid Plant Water Treatment
                      Facility                         10-25

               10.3.4  Former Thornock Lake             10-26
                            vii

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CONTENTS  (Continued)
          10.4 Utilization of Permanent Solutions and
               Alternative Treatment Technologies to
               the Maximum Extent Practicable          10-26

     11   Documentation of Significant Changes          11-1

          11.1 Preferred Alternatives as Presented
               in the Proposed Plan                     11-1

          11.2 Change in Selected Remedy for
               Lower Lake                               11-2

        .  11.3 Change in Implementation times for
               Selected Alternatives                    11-3

               11.3.1  Lower Lake                       11-4

               11.3.2  Speiss Granulating Pond and Pit  11-4

               11.3.3  Acid Plant Water Treatment
                       Facility                         11-5

               11.3.4  Former Thomock Lake             11-5

     12   References                                    12-1


Appendix A     Responsiveness Summary


BOIT727/015.50/jms
                            viii

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TABLES

                                                        Page

5-1  Ranges and Values of  Arsenic,  Cadmium,  and  Lead
     in the Speiss Pond/Pit,  Acid  Plant,  and Lower
     Lake Process Fluid Circuits                          5-2

6-1  Cancer Potency Values and References Doses           6-4

7-1  Specific Actions for  Each Alternative               7-3

7-2  Costs and Implementation Times for Remediation
     Alternatives                                       7-10

10-1 Description and Analysis of  Federal Applicable or
     Relevant and Appropriate Requirements (ARARs)       10-6

10-2 Description and Analysis of  Montana State Applicable
     or Relevant and Appropriate  Requirements (ARARs)  10-12


FIGURES

1-1  Location Map                                        1-2

1-2  Process Pond Location Map                           1-4

5-1  Chemical Profile and  Stratigraphic Comparison
     for Lower Lake                                      5-3

5-2  Process Pond Fluid Sample Sites                     5-4

7-1  Proposed Locations for Steel Tanks and a Runoff
     Replacement Pond                                    7-8

7-2  Proposed Speiss Granulating Pit and Pond
     Replacement Facilities                              7-23


BOIT727/015.50/jms
                             ix

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                         RECORD  OF DECISION
                            DECLARATION

                      East  Helena Smelter Site
                   Operable Unit 1;  Process Ponds
                        East Helena, Montana
                   STATEMENT  OF  BASIS AND  PURPOSE

This decision document presents the selected remedial action for
the Asarco smelter process ponds, an operable unit of the East
Helena Smelter Site, in East Helena, Montana, developed in accor-
dance with the Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act of 1986 (SARA), 42 USC Sec.
9601-9675 and the National Contingency Plan  (NCP), 40 CFR Part 300.
This decision is based on the administrative record for the site.'

By signature below, the State of Montana concurs in this Record of
Decision (ROD).  All determinations reached  in the Record of Deci-
sion were made in consultation with the State of Montana, which has
participated fully in the development of this Record of Decision.
The  administrative record is available for public review at the
U.S.  Environmental Protection Agency,  301 South Park, Helena,
Montana, 8 a.m. to 5 p.m., Monday through Friday.

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                       ASSESSMENT OF THE  SITE

Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this ROD, may present an imminent and substantial endangerment
to public health, welfare, or the environment.
                     DESCRIPTION OF THE REMEDY

This response action is the first such action at the East Helena
Smelter Site.  In 1987, the site was segregated into five operable
units:

       •    Process ponds and fluids

       •    Groundwater

       •    Surface water, soils, vegetation, livestock,  fish,  and
            wildlife

       •    Slag pile

       •    Ore storage areas

Also in 1987, EPA identified the process ponds  as  the  first
operable unit for remedial action under an  accelerated schedule.
Existing data indicated that the process ponds  were  the most

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 significant and well characterized sources impacting the ground-
 water, both on and off the plant site.

 The response action selected by the Environmental Protection Agency
was developed as a remediation strategy for cleanup of the process
ponds.  The process ponds consist of four discrete areas:

       •    Lover Lake

       •    Speiss granulating pond and pit

       •    Acid plant water treatment facility

       •    Former Thornock Lake

Each of the four process ponds poses near- and long-term public
health and environmental threats of varying magnitude.  The res-
ponse action for each process pond is described briefly below, and
in greater detail in the Decision Summary.  The response actions
selected will eliminate future contact between process waters and
the underlying soils and groundwater.  Soils and sediments from all
four process ponds will be excavated and treated by onsite smelt-
ing.  Other major components of the selected remedy include:

LOWER LAKE

•      Replace Lover Lake with two large steel tanks  as  the plant's
       primary holding facility for process vaters

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 •      Treat Lower Lake water in place by  coprecipitation  of metals
       and arsenic

 •      Construct lined, contained drying pads for saturated
       sediments

 •      Excavate the most highly contaminated sediments and treat by
       smelting onsite.  It is estimated that approximately
       45,000 cubic yards (wet volume) of  contaminated sediments
       will require excavation; however, the actual volume will not
       be known until additional sampling  is conducted in  the
       remedial design phase and actual excavation is underway.
       After drying, the sediment volume will be reduced to
       18,000 cubic yards of sediments which will be smelted.

 •      Construct a lined pond for emergency containment of stora
       runoff

SPEISS GRANULATING POND AND PIT

 •      Replace existing pond with tank and secondary containment
       facility

•      Replace existing speiss granulating pit with a new, lined
       facility

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 •      Excavate soils and treat by smelting onsite.   Approximately
       3,700 cubic yards of contaminated soils will  be  excavated
       and treated; however, the actual volume will  not be  known
       until additional sampling is conducted in the remedial
       design phase and actual excavation is underway.

ACID PLANT WATER TREATMENT FACILITY

•      Remove existing settling dumpsters and pond

•      Excavate contaminated soils and return the metals to the
       process by which they were generated by smelting onsite.
       Approximately 6,250 cubic yards of contaminated soils will
       require excavation; however, the actual volume will not be
       known until additional sampling is conducted in the remedial
       design phase and actual excavation is underway.  This
       includes both sediment drying areas for the acid plant water
       treatment facility.

•      Replace existing settling dumpsters and pond with closed
       circuit filtration treatment system

FORMER THORNOCK LAKE

•      Excavate sediments and treat by smelting onsite.
       Approximately 200 cubic yards of contaminated sediments will
       be excavated and smelted; however, the actual volume will

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       not be known until additional sampling is conducted in the
       remedial design phase and actual excavation is underway.
                         CONTINGENCY REMEDY

The selected remedy involves innovative technology with respect to
treatment of water in Lower Lake.   Small-scale laboratory tests
have shown promising results for precipitating arsenic and metals
in place.  This coprecipitation process is expected to be success-
ful in reducing the concentrations of metals and arsenic to accept-
able levels.  However, because large scale testing has not been
conducted, a more proven water treatment process is included in
this Record of Decision as a contingency remedy.

If pilot scale testing of in situ coprecipitation methods proves
this innovative technology to be impractical or inadequate, the EPA
will require construction of a water treatment facility on the
smelter site that vould be capable of removing metals and arsenic
to prescribed standards for discharge to a publicly-owned waste
water treatment plant.
                            DECLARATION
The selected remedy and the contingency remedy are protective  of
human health and the environment, comply with most Federal  and
State requirements that are legally applicable or relevant  and

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 appropriate to the remedial action, and are cost-effective.  The
 legally applicable or relevant and appropriate requirements (AJlARs)
 with which the selected remedy does not comply are hereby waived
 (Refer to Chapter 10 of the Decision Summary, "Statutory Determina-
 tions").  This remedy utilizes permanent solutions, alternative
 treatment, and resource recovery technologies to the maximum extent
 practicable and satisfies the statutory preference for  remedies
 that employ treatment that reduces toxicity, mobility,  or volume as
 a principal element.  Because this remedy will result in hazardous
 substances remaining onsite above health-based levels,  a review
 will be conducted within 5 years after commencement of  remedial
 action to ensure that the remedy continues to provide adequate pro-
 tection of human health and the environment.
 Signature;
James J^^Sc^rerer   /                                           Date
Regional Administrator  (Region VIII)
U.S. Environmental Protection Agency
In Concurrence;
Donald E?~Pizzini, Director *                                   Date
Montana Department of Health and
  Environmental Sciences
BOIT727/012.50/jms

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                     RECORD OF DECISION
                           SUMMARY

                   1  DESCRIPTION OF SITE

The East Helena Smelter Site is located in the community of
                                                    i
East Helena, in Lewis and Clark County, Montana (see
Figure 1-1).  The site is the location of a primary lead
smelter that has operated for 100 years and has also
recovered zinc during much of its existence.  The plant
site, occupying approximately 80 acres, is owned and
operated by Asarco, formerly American Smelting and Refining
Company, and the sources of contamination are from within
the plant site.

The community of East Helena has a population of 1,676
according to the 1980 census.  Approximately 3 miles Co the
west is the City of Helena, with a population of over
35,000.  Residential areas of East Helena are within
1/4 mile of the main area, separated from the site by U.S.
Highway 12 and a rail line.

The site is located in the Helena Valley of western Montana.
Seasons typically consist of cold winters, warm summers with
moderate thunderstorm activity, and a fairly consistent wet
spring.  Much of the moisture in the area comes in the form
of late spring and early summer rain, and there are sig-
nificant winter snow accumulations at higher elevations in
                             1-1

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     %
                              EAST  HELENA
            ASARCO EAST HELENA
                 PLANT LOCATION
SCALE: 1' • 3  miles (approx.)
                                                     NORTH
                                                 Figure 1-1. Location Ma

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 the mountains peripheral to the Helena Valley.  Annual pre-
 cipitation averages about 10 inches in the Helena area.

 The East Helena Smelter Site is adjacent to Prickly Pear
 Creek.  The site is underlain by unconsolidated alluvium
 deposited by the ancestral Prickly Pear Creek.  The alluvial
 deposits have variable permeabilities and consist of layers
 and mixtures of cobbles, gravel, sand, silt, and clay.
 Underlying the alluvium and present exposures west and north
 of the site are fine-grained Tertiary volcanic ash tuff de-
 posits, having low permeabilities, and having weathered to a
 fine-grained clay in some locations.  Surface water and
 groundwater in the area flow from south to north, exiting in
 the northeastern corner of the Helena Valley into Lake
 Helena.

 The sources of contamination at the site are primary and
 fugitive emissions and seepage from process ponds and
 process fluid circuitry.  The affected media include under-
 lying soils, groundwater, surface water, vegetation, live-
 stock, fish, and other aquatic organisms, wildlife, and the
 air of the Helena Valley.  The effects of the contamination
have been measured over a 100-square-mile area.

The areas covered by this ROD include the process ponds:
Lover Lake, the speiss granulating pond and pit, the acid
plant water treatment facility, and former Thornock Lake.
Their locations are shown in Figure 1-2.
                             1-3

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                 er
       orncck. Lake
   Replacement \ank
      Speiss
 Granulating
                                   (Deiss  Granulating  Pond
Ad  Plan
^ Water
 Treatment
    Facility
                                                          Lower
                                                            Lake
                             Acid Plant
                             Sedincnt
                             Drying Areas
Process Pond
      Process Fluids
      Renoved to a
      Steel Holding
      Tank
                                                          Figure 1-2
                                                          Process Pond Location Ma

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Lower Lake collects and stores water utilized in the main
smelter process water circuit as well as storm water runoff.
The speiss pond stores water that is used in the speiss pit
to cool the hot speiss from the dross plant as part of a
granulation process.  The acid plant water treatment
facility removes particulates from the scrubber fluid.
Former Thornock Lake was used to settle suspended solids
from the main process water circuit.  In October 1986, the
lake was replaced by a tank and the lake is no longer in
use.

The primary contaminants are arsenic and heavy metals in the
process fluids beneath the process ponds which are in turn
the principal sources of groundwater contamination at the
site.   The stratigraphy underlying Lower Lake consists of  1
to 3 feet of artificially deposited sludge and partially
suspended silt and clay, underlain by 13 to 15 feet of fine-
grained sediments.  Concentrations of arsenic and metals in
Lower Lake sediments are the highest in the upper 1 to 3
feet and generally decrease with depth.  Strata near the
speiss granulating pond and pit and the acid plant water
treatment facility consist predominantly of gravels and
cobbles in a sandy silt matrix.  Arsenic and metals con-
centrations are higher near the surface and generally
decrease with depth with some increase in the saturated
zone.   Former Thornock Lake bottom sediments generally
consist of fine-grained, plastic organic clay with elevated
                             1-5

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concentrations of arsenic and metals, and are underlain by
coarse-grained sand, gravel, and cobbles.  Arsenic and
metals concentrations decrease with depth.

BOIT727/001.50/jai
                             1-6

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         2  SITE HISTORY AND ENFORCEMENT ACTIVITIES
                   2.1   SMELTER OPERATIONS

The Asarco smelter began operations in 1888 and currently
processes ores and concentrates from around the world.  In
1927, the Anaconda Company constructed a plant adjacent to
the lead smelter for the purpose of recovering zinc from the
smelter's waste slag.  This zinc plant was purchased by
Asarco in 1972, but operations were discontinued in 1982.
In 1955, the American Chemet Corporation constructed a paint
pigment plant adjacent to the smelter; it is still
operating.  Both Anaconda, which is now a division of the
ARCO Coal Company, and American Chemet Corporation have been
identified as potentially responsible parties (PRPs) at this
site, in addition to Asarco.
              2.2  ENVIRONMENTAL  INVESTIGATIONS

The site was the focus of several environmental investi-
gations prior to its listing on the National Priorities List
(NPL) in 1983.  The following studies have been prepared for
the site:

     •    A Joint EPA-State Air Quality Bureau (AQB) study
          in 1969 of arsenic, lead, zinc, and sulfur dioxide
                             2-1

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          emissions, followed by monitoring and sampling
          studies through the mid-1970s

      •    A 1969 study of contaminants in soils in the
          smelter area by the United States Geological
          Survey (USGS)

      •    Asarco's annual soil and vegetation surveys con-
          ducted between 1974 and 1983

      •    A 1972 area environmental pollution study by the
          EPA, which included vegetable samples from local
          gardens

Many  of the studies conducted at the site were intended to
measure compliance of the smelter with state and federal
emissions and air quality standards.  Monitoring conducted
by the state in 1972 revealed that sulfur dioxide  (S02)
exceeded ambient air quality standards.  In 1974 the state
held  hearings with the industrial contributors to work
toward developing control strategies to reduce S02 in
emissions and ambient air.  Between 1974 and 1977, an acid
plant was built by Asarco to control S02 emissions.
Subsequently, lower S02 levels  were  measured in the smelter
vicinity.  During 1978 and 1980, S02 standards  were violated
occasionally.  A tall stack was added to the blast furnace
baghouse in 1981 to generally prevent stack gases  from
impacting areas close to the smelter where most people
                             2-2

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reside.  The smelter has been in continual compliance with
state and federal Ambient Air Quality Standards for sulfur
dioxide since 1983.
                   2.3  BLOOD-LEAD STUDIES

The Montana Department of Health and Environmental Sciences
(MDHES) and the National Centers for Disease Control (CDC)
in Atlanta conducted the first blood-lead studies of resi-
dents in the area in 1975 to determine if their blood-lead
levels exceeded action levels.  An action level is a level
at which, based on available information, a contaminant is
considered to be a human health risk.

The CDC's action level for blood-lead has been reduced over
time.  The level was 30 micrograms of lead per deciliter of
blood at the time of the 1975 testing.  It was changed to 25
micrograms per deciliter in 1984 to reflect new evidence on
health risks from lead poisoning.  The 1975 blood-lead
studies of children were conducted prior to installation of
air pollution equipment at the smelter by Asarco.  The CDC
has indicated that another reduction in the action level is
forthcoming.  The Lewis and Clark County Health Department
conducted additional blood-lead studies in 1983.  Blood-lead
studies were also conducted for Asarco in 1987 and 1988 by
the county health department.  Asarco is considering addi-
tional blood-lead studies in the future.  These studies will
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be carried out at different times of the year to determine
whether blood-lead levels vary during different seasons of
the year.

The 1975 study found that 34 percent of the 90 children
tested had blood-lead levels above the action level.  The
1983 study, performed after Asarco installed air pollution
control equipment at the plant, disclosed only one of
396 children above the action level.  According to CDC,
after retesting, that child's blood-lead level was found to
be below the action level.  However, if the action level had
been 25 micrograms per deciliter in 1983, 6 children would
have been above the action level.  The CDC concluded that
the blood-lead levels of all other children tested showed no
cause for public health concern.

The results of a recent study, performed by Asarco between
October and December 1987, indicated that four out of  the
363 residents tested (including approximately 50 adult
women) had blood-lead levels above the action level of 25
micrograms per deciliter.
2.4  SUPERJUND INVESTIGATION WORK AND ENFORCEMENT ACTIVITIES

There have been two Administrative Orders on Consent  entered
into with Asarco for activities at the East Helena  smelter
site:
                             2-4

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      •    Docket number CERCLA VIH-84-006:  Phase I
          remedial investigations of surface water and
          groundwater, and site endangerment assessment

      •    Docket number CERCLA VIH-89-10:  Phase II
          remedial investigations, endangerment assessment,
          and feasibility study of all contaminated media at
          this site

General Notice Letters and Requests for Information, pur-
suant to 104(e) of CERCLA were sent to the American Chemet
Corporation on February 23, 1987, and to the Arco Coal Com-
pany on March 12, 1987.

The administrative record, available for public review at
the EPA (301 South Park, Helena, Montana), contains a
complete documentation of administrative orders for the
site.  The site was listed on the National Priorities List
(NPL) of Superfund sites in September 1983.  The events that
led to the site's listing on the NPL included findings of
contaminated soils in East Helena residential areas,
elevated metals levels in the air, and contaminated process
ponds over shallow ground water near the plant.

The EPA began its Remedial Investigation  (RI) field work in
May 1984.  The resulting Phase I RI data report for soils,
vegetation, and livestock was released in May 1987.  Asarco
                             2-5

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began the field work for its water resources investigation
in November 1984, including studies of groundwater,  surface
water, process ponds, and the process fluids circuitry.

The EPA and Asarco released the results of their RI studies
about the possible effects of site contamination on soils,
plants, livestock, and water resources in June 1987.  The
studies showed metals and arsenic contamination in' soils,
plants, livestock, surface water, and groundwater.  The EPA
determined that Asarco's water resources investigation and
report were inadequate in defining the nature and extent of
surface and groundwater contamination.  Therefore, Phase II
studies were ordered by the EPA.

Both study phases indicate the contamination to be greatest
in all media nearest the smelter.  Arsenic and lead were
found at elevated concentrations in Prickly Pear Creek.
Contamination was found occasionally in some Prickly Pear
Creek samples at levels above federal drinking water
standards.  Blood-lead -arsenic, -cadmium, and -zinc levels
in eight cattle herds from near the smelter were found to  be
higher than in a control herd tested for comparison.

Asarco has completed the Phase II studies of surface and
groundwater, soils, vegetation, and livestock.  The feasi-
bility study for the process ponds operable unit was pub-
lished by Asarco in August 1989.  All Phase I and Phase  II
RI reports, the feasibility study for the process ponds,  and
                             2-6

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other pertinent documents and data relied on for this ROD
are contained in the Administrative Record for this site.

Special Notice for remedial design and remedial action as
described in Section 122 of CERCLA has not yet been provided
to the Responsible Party.  The EPA anticipates issuing
Special Notice approximately 2 weeks subsequent to finaliza-
tion of this Record of Decision.  Negotiations are predicted
to commence shortly thereafter and culminate in a judicial
consent decree for implementation of remedial design and
remedial action, recovery of all past EPA expenditures
related to the site, and provision for ongoing reimbursement
for oversight costs.  The consent decree should be
formalized no later than 120 days after issuance of Special
Notice.
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             3  COMMUNITY RELATIONS ACTIVITIES

To dace,  the EPA and MDHES  have  initiated  several community
relations activities at  the East Helena  Smelter Site.  These
include:

     •     Preparation of a  community relations plan in  1984
          and revisions  of  that  plan in  1988

     •     Preparation and distribution of  fact sheets

     •     Holding  several public meetings

     •     Onsite interviews with residents and officials
          regarding  community  concerns about  the  site

     •     Joint  EPA  and  MDHES  meetings with the media  to
          update them on current and future events

     •     Periodic meetings with local and state  officials
          to discuss the status  of EPA and MDHES  activities

     •     Formation  of a citizen's advisory group,  the East
          Helena Superfund  Task  Force, as  a result  of  the
          need for discussions between the task  force  and
          the EPA, with  numerous meetings  having  been con-
          ducted
                            3-1

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      •    Esta,. ^ishment of an information, repository at
          EPA's offices in Helena to make site-related docu-
          ments available to the community

      •    Progress reports to community members

      •    Additional information concerning community rela-
          tions is available in the Responsiveness Summary
          (Appendix A)

Asarco has participated extensively with the EPA and MDEES
in community relations activities such as public meetings
and press releases.

The EPA and MDHES have maintained an active community
relations program during RI/FS activities.  Local media,
including Helena television station KTVH and the Helena
newspaper, The Independent Record, have regularly covered
site  issues and concerns.  Fact sheets or project updates
were prepared at various stages to inform East Helena
residents of the status of site activities.  The EPA  and
MDHES conducted interviews of local officials and residents
to determine the adequacy of the agencies'  information
distribution system.

An administrative record has been established for the East
Helena Smelter Sice.  The record is available near  the site
in the docket review room of the U.S. Environmental
                             3-2

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Protection Agency's Montana Operations Office,  301  South
Park, Helena, Montana.  Records at this location may be
reviewed during normal business hours.

To assure that interested persons, including potentially
responsible parties, were given the opportunity to  par-
ticipate in the development of the East Helena Smelter Site
administrative record, the following actions have been
taken:

     1.   Pursuant to Section 117(a) of CERCLA, a Proposed
          Plan for remediation of the process ponds was made
          available to East Helena citizens, legislators,
          potentially responsible parties,  and other
          persons.  The plan summarized the RI/FS process,
          described the response action alternatives, and
          provided a brief analysis of the  alternatives
          preferred by the EPA and MDHES.   The Proposed  Plan
          was mailed to persons on the EPA  mailing list,
          published in the local newspaper, and made avail-
          able at the Helena office of the  EPA and MDHES.
          Notification of the availability  of the plan was
          made by newspaper notice in the Helena Independent
          Record on August 30 and 31, and on September 1,
          1989.

     2.    Concurrent with distribution of the Proposed Plan
          was the initiation of a 21-day public comment
                            3-3

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               - to allow persons  to  provide  official
          comment on the FS and the proposed  plan for  the
          process ponds.

     3.   To provide another opportunity  for  public comment
          and discussion on the Proposed  Plan and other East
          Helena Smelter Site issues  as necessary, a public
          meeting was held on September  12,  1989, in the
          East Helena Firemen's Recreation Hall.   The date,
          time, and place of this  public  meeting  was
          published in the Proposed Plan.  Also,  public ser-
          vice announcements were  broadcast  as news items  on
          the local radio and television  stations.

     4.   Verbal comments and questions were  noted during
          the meeting.  In many instances, responses were
          Immediately supplied to  the public  at the meeting.
          Written comments were accepted  for the  duration of
          the public comment period.   A  response  has been
          prepared for each of these  written comments.  The
        .  comments, questions, and responses are  contained
          in the Responsiveness Summary  attached  to this
          document.

The EPA has published this Record  of  Decision as  a final
plan for remediation of the process  ponds.  Included in this
final plan is a discussion of any  significant changes  from
the Proposed Plan, and responses to  each of the  significant
                            3-4

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comments or questions submitted during the public comment
period.  Announcement of the availability of this ROD will
be made by notice in the local newspaper.  This ROD will be
made available for review in the public repository, and for
review and copying at the EPA office in Helena, Montana.

The availability of technical assistance grants for citizen
groups was publicly noticed in various Montana newspapers
during 1988.  Further notice was verbally issued in East
Helena during a presentation to the East Helena Superfund
Task Force, a citizens* advisory group of five people.  No
grants were requested or awarded for this action.
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            4  SCOPE AND ROLE OF RESPONSE ACTIONS
              4.1  OPERABLE UNIT IDENTIFICATION

In 1987, the East Helena Smelter Site was segregated into
five operable units.  The purpose of the operable unit
approach was to expedite remedial investigation and feasi-
bility studies on well-characterized units.  The operable
units at the East Helena Smelter Site are:

     •    Process ponds and fluids

     •    Groundwater

     •    Surface water, soils,  vegetation, livestock, fish,
          and wildlife

     •    Slag pile

     •    Ore storage areas

The potential interactions among these operable units were
evaluated.  The interactions were evaluated from the per-
spective of how the remedial action taken on each operable
unit would affect the subsequent remediation of other units.
Some interactions of operable units in this final list were
identified; however, by proper planning and scheduling,  any
                             4-1

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potential inconsistencies can be minimized.   The separation
of the site into these five operable units will allow for
faster action on those units that are well-characterized.

The process ponds are known to be the primary sources of
groundwater contamination and can be remediated separately
from other sources.  The extent and degree of groundwater
contamination, although potentially caused by several
sources, can be remediated as a separate unit with some con-
sideration of how it interacts with the process ponds.

The ore storage areas and the slag pile represent distinct
sources of contamination, and although they have some common
exposure pathways, they can be remediated as separate
sources.  The contaminated offsite surface soils represent
the major contaminated media from the smelter's air emis-
sions and represent a logical operable unit containing not
only the contaminated surface soils and surface water, but
also the vegetation, livestock, wildlife, and aquatic life
contained in the study area.  The following subsections
present a brief description of each operable unit.

4.1.1  PROCESS PONDS AND FLUIDS

The process ponds operable unit includes Lower Lake,  former
Thornock Lake, the speiss granulating pond and pit, and  the
acid plant water treatment facility.  For each process pond,
the operable unit includes the process water and
                             4-2

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contaminated sediments and soils under each pond to the
depth that they are a source of groundwater contamination or
intersect with groundwater.

4.1.2  GROUNDWATER

The groundwater operable unit includes all groundwater that
has been contaminated above levels posing a threat to public
health or the environment, or levels exceeding applicable or
relevant and appropriate requirements.  This unit also
includes the sediments above and below the aquifer that have
elevated heavy metals concentrations caused by attenuation
of metals from the groundwater or surface water as it passed
through the sediments.

4.1.3  SURFACE WATER, SOILS, VEGETATION, LIVESTOCK,
       FISH, AND WILDLIFE

This operable unit includes all contaminated surface soil
both on the Asarco site as well as offsite.  Also included
are contaminated surface water, vegetation, livestock,
aquatic life, and wildlife.

4.1.4  SLAG PILE

This operable unit includes the slag pile and any con-
taminated soil under the slag pile.  The primary potential
impact on other operable units is the potential of
                             4-3

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 groundwater  contamination from the slag piles.  Current
 investigations will determine if this is occurring.

 4.1.5  ORE STORAGE AREAS

 This operable unit includes the ore storage areas and any
 contaminated soils under the paved or unpaved portions of
 the storage areas.
                    4.2  RESPONSE ACTIONS

The EPA has identified the process ponds as the first
operable unit under the accelerated schedule.  Existing data
indicate that process ponds were the most significant and
well-characterized sources of contamination impacting the
groundwater.  The process fluids circuitry will be addressed
in the Comprehensive Remedial Investigation/Feasibility
Study (RI/FS) to be completed in the fall of  1989.

This ROD details the remedy selection process for the
process ponds consisting of four areas:  Lower Lake, the
speiss granulating pond and pit, the acid plant water treat-
ment facility, and former Thornock Lake.  The Process Ponds
RI/FS was conducted in accordance with the Comprehensive
RI/FS Work Plan.  The RI/FS activities were performed by
Asarco with oversight by and approval of the United  States
Environmental Protection Agency under the authority  of the
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Comprehensive Environmental, Response,  Compensation,  and
Liability Act (CERCLA) and the Superfund Amendments and
Reauthorization Act of 1986 (SARA).

The response actions selected for implementation at the
process ponds are designed to:  alleviate the primary
threats to public health and the environment, prevent
current or future exposure to the contaminated soils, and
reduce contaminant migration into the groundvater.  This
operable unit will be the first response action for this
site, it will be cost-effective, and it will be consistent
with the permanent remedy for all operable units.
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             5  SUMMARY OF SITE CHARACTERISTICS
                 5.1  CONTAMINATION SOURCES

There are five potential sources of contamination at the
East Helena Smelter Site:  smelter air emissions, the slag
pile, ore storage areas, process ponds, and process fluids.
The contaminants of primary concern are arsenic, cadmium,
lead, copper, and zinc.  Contamination from the plant has
been found in air, surface soils, groundwater, and surface
water.  Dissolved arsenic in the shallow groundwater under
portions of East Helena has been measured at approximately
1.2 mg/L.  Contamination from these media has affected
humans, livestock, vegetation, and fish, although the
effects have not been fully defined.  Under certain con-
ditions, heavy metals contamination can lead to several
human health problems including central nervous system
damage, kidney disease, and cancer.  Analytical data for
water and sediments are shown in Table 5-1 and Figure 5-1,
respectively.  Locations of sampling points are shown in
Figure 5-2.

Several ponds at the site are used for storing water from
Prickly Pear Creek as well as for retention of process
water.  This ROD addresses four major process fluid ponds:
Lower Lake, the speiss granulating pond and pit, the acid
plant water treatment facility, and former Thoraock Lake
(refer to Figure 1-2).
                             5-1

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                                              Table 5-1
              RANGES AND AVERAGE VALUES OF  ARSENIC, CADMIUM,  AND LEAD  IN THE SPEISS
                   POND/PIT, ACID  PLANT,  AND LOWER  LAKE PROCESS  FLUID CIRCUITS.
Locat ion
S pel ss Pond/Pit
SP-1 Total
Di •solved
SP-2 Total
Dissolved
Acid Plant
AP-1 Total
(Input process Dissolved
line to Lower Lake)
AP-2 Total
(Treatment Dissolved
facility inlet)
AP-I Total
(Treatment outlet) Dissolved
Lower Lake
LL- 1 Total
Dissolved
LL-2 Total
Dissolved
Lower Lake Total
Process fluid Dissolved
(1984 1987)
Arsenic
Rantju Average

55 3750 1690
55 - 3733 1494
2858 - 1800 3329
3650 3731 3691

0.043 0.41 0.19
0.035 - 0 354 0.16
1625 3475 2477
1625 2920 2369
17 23 3 19.6
15.1 18 8 17.8

14.7 25 .0 211
153 235 17.6
15.6 20.6 19.1
14.8 19 . 5 17.2
10.5 )6 0 19.9
8.25 29.0 17.2
Cadmium
Range Average

0.018 - 3.9 0.69
0.005 • 1.13 0.27
<0 004 0. 300 0.152
<0.004 - 0.107 0.055

0 008 - 0.205 0.080
0.0038 • 0.153 0.057
37.5 - 550 228
J7.5 - 550 211
0.405 - 1.78 0.858
0.029 • 0.451 0. 23 J

0 408 5 . 09 2.77
0 051 2.76 1.33
0 394 1.62 0.81
0.016 0.476 0 250
0.225 2.05 1.05
0.175 0. 750 0. J9
Lead
Range Average

0.257 - 24 4.45
0.018 - 0.061 0.028
0.153 1.750 0.951
<0.030 - 0.076 0.053

0.156 - 0.433 0.298
0.0062 - 0.0166 0.045
8.42.- 843 109
6.75 • 25 15.6
1.63 • 4.06 2.31
0.01 • 0.045 0.025

0.93 48.) 26.7
0 004 0.538 0 12
1.13 2.45 1 /
O.OOJ 0.029 0.01
1.25 24 7 5 11
0.022 0.2)8 O.OU
Note:    All  concentrations are in mi I I iqi .»mu per liter.
Sonice:  tSE.  19HB

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u
  3915 *
o
&
d
  3905
o
   3995
w
0
                                                                      Prlokly Pear Crook
                          200                400                 600


                                  HORIZONTAL DISTANCE (Feet)



                        LEGEND
                                                                    600
      ta
Ooze or Sludge




Silt and




Sand




      and Sand
                                            Arsenic (llg/Kg)
                                                                  Chemical Piofilc and Slraligraj'lm

                                                                  ( 
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NORTH
      L   E   .G    E   N '  D
      Acid  Plant Slowdown  Dragline
      Process Pond  Sanple Sites
                                                   Figure 5-2
                                                   Process Pond "n
                                                   Sample Sites

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5.1.1  LOWER LAKE

Lower Lake collects and stores water used in the main plant
process circuits and runoff from the plant site.  The pond
is approximately 7 acres in surface area and has a capacity
of about 11 million gallons.

Lower Lake process waters contain up to 25 mg/L total
arsenic and 48 mg/L total lead.  Concentrations of other
metals in the process waters are similarly elevated.  The
bottom sediments of Lower Lake contain up to 2,800 mg/kg
arsenic and 15,000 mg/kg lead.  Concentrations of other ele-
ments in the bottom sediments are similarly elevated and
these concentrations decrease with increasing depth  (refer
to Figure 5-1).  The EPA has classified such bottom deposits
in surface impoundments at all lead smelters as a hazardous
waste.

5.1.2  SPEISS GRANULATING POND AND PIT

The speiss granulating pond provides storage for water used
to cool the hot speiss from the dross plant.  During speiss
granulation, molten material is allowed to flow into the
pit.  Water pumped from the speiss pond is fed through
sprayers onto the hot speiss material in the pit.
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The water then drains through a 12- to 14-tnch-diameter mild
steel pipe back to the speiss granulating pond.   This water
is again recirculated during the granulating process.  Plant
process water from Lower Lake is added to the pond when
makeup water is needed.  The speiss granulating pit was con-
structed on the original concrete slab on the ground floor
of the dross reverb building.  Mild steel plating was used
to-make an enclosure for this pit.  The speiss granulating
pond is lined with 8 inches of concrete and is approximately
20 by 70 feet with a maximum depth of 4 feet.  In August
1988, a high density polyethylene (HDPE) liner was installed
over the concrete in the speiss pond.

Soils under the speiss granulating pond and pit contain up
to 1,750 mg/kg arsenic and 5,500 mg/kg lead.  Concentrations
of all elements decrease with increasing depth.  Dissolved
arsenic iii saturated soils under this area is as high  as
700 mg/L.

5.1.3  ACID PLANT WATER TREATMENT FACILITY

The acid plant water treatment facility consists of  a  wooden
trough fluid transport system, five particulate settling
dumpsters, and a 68- by 35- by 9-feet-deep settling  pond.
The facility is used to remove particulates  from the
scrubber fluid which is then recirculated to  the scrubbers
                             5-6

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 or  the sinter plant.  A concrete pad underlies the five in-
 line dumpsters.  There are no berms around the pad, and
 fluids leaking onto the pad spill over onto the ground sur-
 face.  The wooden trough transport system is underlain by
 concrete and the natural ground surface.  The settling pond
 is  lined with concrete which is protected from the acidic
 process fluids by an asphalt liner.  Soils under the acid
 plant contain up to 12,000 mg/kg arsenic and 14,000 mg/kg
 lead.  Concentrations of all elements decrease with increas-
 ing depth; however, the soils under the acid plant differ
 from soils and sediments under the other process ponds by
 exhibiting characteristics of EP toxicity throughout the
 soil profile tested.

 5.1.4  FORMER THORNOCK LAKE

 Former Thornock Lake was also part of the main plant process
water circuit and was used primarily for preliminary
 settling of suspended solids.  However, in October  1986,
 Thornock Lake was replaced by a steel holding tank.  This
 former lake no longer contains process  fluids and  only
 bottom sediments remain.

 Sediments from former Thornock Lake  (now dry) contain up to
 120,000 mg/kg arsenic and 38,000 mg/kg  lead.  Concentrations
 of other elements are similarly elevated and  these  con-
 centrations decrease with increasing depth.   Bottom sedi-
ments of former Thornock Lake and all other bottom sediments
                             5-7

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at all lead smelters have been classified by the EPA as a
hazardous waste.
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                      6  SUMMARY OF SITE RISKS
                                     .TH RISKS
An endangerment assessment (EA) was prepared in support of the fea-
sibility study for the process ponds.  This EA evaluated the
current and potential future risks to onsite workers at the Asarco
smelter and discussed the contaminant release and migration mecha-
nisms responsible for transport of contaminants from onsite source
•areas to offsite areas or other environmental media.  The following
discussion is based on the EA presented as part of the process
ponds feasibility study.

6.1.1  CONTAMINANT IDENTIFICATION

The media of concern include contaminated sediments in Lower Lake
and former Thornock Lake, contaminated soils at the acid plant
water treatment facility and the speiss granulating pond and pit,
process water in all areas except former Thornock Lake, surface
water in Prickly Pear Creek, and groundwater below the site and
East Helena.

Twenty seven chemicals (metals and arsenic) were analyzed  in the
media identified above.  Inorganic contaminants are present
throughout the soils, sediments, surface water, and groundwater at
the site.  Indicator chemicals were  selected from the parameter
list to identify the contaminants that pose the greatest potential
                                6-1

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 risk to public health and the environment at the areas associated
 with the process ponds.  The contaminants selected as indicator
 chemicals based on their potential to promote or cause adverse
 human health effects were arsenic, cadmium,  and lead.  Copper and
 zinc were added to account for the potential adverse environmental
 impacts particularly relative to aquatic biota.  It is important to
 note that, although only five indicator chemicals were selected,
 there are 18 total hazardous elements at elevated concentrations in
 the surface water, groundwater, soils, and sediments at the site.

 Analytical data for water and sediments are presented in Table 5-1
 and Figure 5-1.  Selection of indicator chemicals was based in part
 on the available analytical data and on toxicity to human and
 environmental receptors.  Mobility and persistence in the
 environment were also considered.

 6.1.2  EXPOSURE ASSESSMENT

The exposure assessment uses site description and environmental
 fate-and-transport information in identifying potential exposure
pathways to onsite receptors.  An exposure pathway is the pathway
by which human or environmental receptors may be exposed to the
contaminants from a contaminant source.  The exposure assessment
evaluates the exposure pathways and includes examination of the
 following:

       1.   Known contaminant sources
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        2.    C   taminant migration pathways

        3.    Locations where human or environmental receptors could
             be  exposed

        4.    Likely route of exposure (i.e., ingestion, dermal ab-
             sorption, and inhalation)

 If all  of these components are present, then the exposure pathway
 is considered to be complete and would be expected to contribute to
 the  total exposure from the process ponds.  Only those exposure
 pathways associated with the process ponds that are considered to
 pose a  health risk will be addressed.

 Cancer  Potency  Factors (CPFs) and Reference Doses  (RFDs) for the
 contaminants of concern are presented in Table 6-1.  The CPFs have
 been developed  by EPA's Carcinogenic Assessment Group for estinat-
 ing  excess lifetime cancer risks associated with exposure to poten-
 tially  carcinogenic chemicals.  The CPFs, which are expressed in
 units of (mg/kg/day)"1, are multiplied by the estimated intake of a
 potential carcinogen, in mg/kg/day, to provide an  upper-bound
 estimate of  the excess lifetime cancer risk associated with
.exposure at  that intake level.  The term "upper-bound" reflects  the
 conservative estimate of the risks calculated  from the CPF.  Use of
 this  approach makes underestimation of the actual  cancer risk
 highly  unlikely.  Cancer potency factors are derived  from the
 results of human epidemiological studies of chronic animal  bio-
                                6-3

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                                                         Table 6-1
                                       CANCER  POTENCY VALUES AND  REFERENCE DOSES
Parameter
Arsenic
Cad«iu«
Copper
Lead
tine
TOXICITY VALUES FOR NONCARCINOGENIC EFFECTS
Oral Rout*
AIC * R«D b
(•g/kg/day) <»g/kg/day)
5.0B-04
3.7B-03
1.4B-03*
2.1B-01
Inhalation Rout*
« b
AIC * RfD
(ing/kg/day) (ng/kg/day)
l.OE-02
4.3B-04
l.OE-02
TOXICITY VALUES FOR CARCINOGENIC EFFECTS
Oral Rout*
Potency Factor
(mg/kg/day)-l H/B C
1.5d A
B3b
Inhalation Rout*
Potency Factor
(ing/kg/day)-! H/I
50 A
6.1 Bl
B3 b
 a Sourc*:   U.S.  BPA, 1986c.
 b Sourc*:  BPA  1969a, BPA 1989*
 c H/B • Height of  Evidence rating
 d Source:   Thooas,  1968.
 e This value has been withdrawn by EPA.
NOTE:   Scientific notation uaed for ease in reading  small values
       im the  value 0.0003.
For example, the notation 3.0E-04

-------
 assays to which animal-to-human extrapolation and uncertainty
 factors have been applied.

 Reference doses (RfDs) have been developed by EPA for indicating
 the potential for adverse health effects from exposure to chemicals
 exhibiting non-carcinogenic effects.  The RfDs, which are expressed
 in units of mg/kg/day, are estimates of lifetime daily exposure
 levels for humans, including sensitive individuals.  Estimated
 intakes of chemicals from environmental media  (e.g., the amount of
 a chemical ingested from contaminated drinking water) can be
 compared to the RfD.  The RfDs are derived from human
 epidemiological studies or animal studies to which uncertainty
 factors have been applied (e.g., to account for the use of animal
 data to predict effects on humans).  These uncertainty factors help
 ensure that the RfDs will not underestimate the potential for
 adverse non-carcinogenic effects to occur.

 Excess lifetime cancer risks are determined by multiplying the in-
 take level with the cancer potency factor.  These risks are  proba-
 bilities that are generally expressed in scientific notation (e.g.,
 1E-6).  An excess lifetime cancer risk of 1E-6 indicates that, as  a
plausible upper bound, an individual has a one in one million
 chance of developing cancer as a result of site-related exposure to
 a carcinogen over a 70-year lifetime under the specific exposure
 conditions at a site.

 Potential concern for non-carcinogenic effects of a  single contami-
nant in a single medium is expressed as the hazard  quotient  (HQ)
                                6-5

-------
 (or, the ratio of the estimated intake derived from the contaminant
 concentration in a given medium to the contaminant's reference
 dose).  By adding the HQs for all contaminants within a medium or
 across all media to which a given population may reasonably be
 exposed, the Hazard Index (HI) can be generated.  The HI provides a
 useful reference point for gauging the potential significance of
 multiple contaminant exposures within a single medium or across
 media.

 Environmental monitoring activities performed at the process pond
 areas have confirmed the presence of contaminants of concern in
 surface water, groundwater, subsurface soils, and sediments.  The
 primary sources include:

       I.   Process fluids associated with the process ponds  (i.e.,
            Lower Lake, speiss pond/pit, and acid plant water
            treatment facility)

       2.   Soils and sediments associated with the process ponds
            (Lower Lake, speiss pond/pit, acid plant water
            treatment facility, and former Thornock Lake)

 Contaminants detected in the process pond areas have migrated
 toward the downgradient receptor areas and other environmental
media onsite as well as offsite.

The environmental fate and transport analysis presented  in  the  fea-
 sibility study identified subsurface soil- and  sedimant-to-ground-
                                6-6

-------
water, and groundwater-to-surface water as the primary migration
pathways for metals and arsenic from the process ponds.  Other
migration pathways of potential importance, surface soil-to-air,
surface soil-to-surface water, and air-to-surface soil, were not
considered in the feasibility study.

Based on the results of the environmental fate and transport
analysis, a screening of current and potential future exposure
pathways was conducted to determine which pathways could
potentially expose receptors to arsenic, cadmium, lead, copper, and
zinc migrating from the source areas.  The screening step removes
from consideration those exposure scenarios in which arsenic, cad-
mium, lead, copper, and zinc may be released from the site but  for
which there is less potential for exposure.  The relative impor-
tance of these exposure scenarios compared to other exposure  routes
is not defined.

The elevated levels of arsenic, cadmium, lead, copper, and  zinc
identified in the process fluids, sediments, subsurface soil
samples, and groundwater samples collected during the process pond
RI in conjunction with the results of the contaminant migration
pathway analysis indicate that onsite workers have the potential
for direct contact with contaminants in the process ponds and other
affected media onsite.  Exposure pathways exist  for those receptors
that may com* into contact with groundwater, surface water,  subsur-
face soils, And sediments associated with the process  ponds.
Although onsite workers' occupational health and well-being is  reg-
ulated under OSHA, the exposure pathways are complete  for those
                                6-7

-------
workers who may inadvertently contact contaminants in the course  of
their workday.

The groundwater, surface water, subsurface soils,  and sediment
exposure pathways are also considered to be complete for offsite
receptors.  Offsite receptors include public, livestock, wildlife,
and vegetation.  These exposure pathways are considered in the
site-wide endangerment assessment.

Other sources at the plant may also contribute to potential
exposures to onsite workers.  Therefore, risks were not quantified
in the process ponds feasibility study.  The following information
evaluates all onsite exposure pathways associated with the process
ponds.

Based on results of the sampling performed at the process ponds
area, the process fluids, stratigraphic soils, and sediments were
found to contain elevated levels of arsenic, cadmium, lead, copper
and zinc.  The primary exposure to these contaminants is to workers
during the course of daily occupational activities.  The OSHA
worker requirements are in place; however, only consistent applica-
tion of OSHA protective measures will minimize exposure.
Consequently, some level of exposure to site contaminants is
foreseeable.  Assuming that some level of exposure to site con-
taminants occurs, the potential for adverse human health effects
can be suggested.  The contaminant intakes and resulting risks were
not qualified in the process ponds feasibility study.
                                6-8

-------
 Other  source areas exist pnsite that may contribute to elevated
 levels of arsenic, cadmium, lead, copper, and zinc.  These source
 areas, offsite contamination, and offsite receptors, both human and
 environmental, are addressed in the comprehensive, site-wide
 endangerment assessment.

 According to U.S. EPA, 1987, the East Helena population was
 estimated at 1,647 in 1980.  The population nearest to the Asarco
 smelter resides in the city of East Helena and in rural areas sur-
 rounding the smelter site.

 6.1.3  TOXICITY ASSESSMENT

 The toxicity assessment describes the potential human health
 hazards associated with contaminants identified as indicator
 chemicals for human exposure routes and present within the process
 ponds  areas.  The following summarizes some of the toxicity effects
 of the contaminants of concern.

 6.1.3.1  Arsenic

 Arsenic is a known human carcinogen (Group A) through both
 ingestion and inhalation exposures.  Oral exposures are associated
with skin cancer, and inhalation exposures are known to cause  lung
 cancer.  Acute oral exposure can result  in muscular cramps,  facial
 swelling, cardiovascular reactions, severe gastrointestinal  damage,
 and vascular collapse leading to death.  Inhalation exposures  can
 cause  severe irritation of nasal lining, larynx,  and bronchi.
                                6-9

-------
Chronic oral or inhalation exposure can produce changes in skin,
including hyperpigmentation and hyperkeratosis.  Oral exposures  are
associated with peripheral vascular disease (blackfoot disease.)

6.1.3.2  Cadmium

Cadmium is a known human carcinogen (Group A)  as a result of inhal-
ation exposures.  Increased risk of prostate cancer and perhaps
respiratory tract cancer in workers exposed to cadmium through
inhalation have been documented.  There is no evidence of
carcinogenicity from chronic oral exposure.

For acute exposures by ingestion, symptoms of cadmium toxicity
include nausea, vomiting, diarrhea, muscular cramps, salivation,
spasms, drop in blood pressure, vertigo, loss of consciousness,  and
collapse.  Exposure by inhalation can cause irritation, coughing,
labored respiration, vomiting,  acute chemical pneumonitis, and
pulmonary edema.

Respiratory and renal toxicity are major effects in workers.
Chronic oral exposures can produce kidney damage.  Inhalation can
cause chronic abstractive pulmonary disease, including bronchitis,
progressive fibrosis, and emphysema.  Chronic exposure may be
associated with hypertension.  Cadmium can produce testicular
atrophy, and teratogenic effects in experimental animals.
                                6-10

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6.1.3.3  Lead

Lead salts have some evidence of carcinogenicity in animals.
However, the U.S. EPA Carcinogen Assessment Group has not estab-
lished a slope factor despite listing lead as a Group B2
carcinogen.

Acute inorganic lead intoxication in humans is characterized by
encephalopathy, abdominal pain, hemolysis, liver damage, renal
tubular necrosis, seizures, coma, and respiratory arrest.

Chronic low levels of exposure to lead can affect the hematopoietic
system, the nervous system, and the cardiovascular system.  The
developing child appears especially sensitive to lead-induced
nervous system injury.  Epidemiological studies have indicated that
chronic lead exposure may be associated with increased blood
pressure in humans.  Exposure to lead is associated with sterility,
abortion, neonatal mortality, and morbidity.

6.1.3.4  Copper And Zinc

Copper and zinc are generally less toxic to humans than arsenic,
cadmium, and lead, but can cause adverse environmental  impacts  on
aquatic biota.
                                6-11

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 6.1.4  RISK CHARACTERIZATION INTORMATION

 Results of the field Investigations have identified that the
 process ponds contribute arsenic and metals to subsurface soils,
 groundvater, surface waters, and sediments. This presents a health
 risk to offsite receptors (humans, livestock, wildlife) that may
 come into contact with arsenic and metals which may have migrated
 offsite and have been released into other media.  Additionally,
 other source areas exist onsite that may also contribute to
 elevated levels of arsenic and metals of these same media.
 Therefore, a set of offsite exposure pathways exists for each
 medium.

 Because of the comprehensive nature of the offsite exposure path-
ways, the quantification of these exposure pathways will be per-
 formed in the Comprehensive RI.  The Comprehensive RI will evaluate
 the contribution of all onsite source areas to the exposure path-
ways for offsite receptors, which include:

       1.   Direct contact with contaminated surface soils and
            sediments

       2.   Ingestion or inhalation of contaminated offsite surface
            soils

       3.   Consumption of contaminated plants, livestock or wild-
            life by Helena Valley residents
                                6-12

-------
       4.   Ingestion and dermal exposure to surface water

       5.   Ingestion and dermal exposure to groundwater

The Comprehensive RI will address the overall health risks
associated with exposure to chemicals released form each of the
source areas in each of the environmental media in the study area.
The health risks for all completed exposure pathways onsite and
offsite of the facility will be presented in the Comprehensive RI,
and will be based on the data base obtained from the Comprehensive
RI.  The quantitative EA will be presented in the Comprehensive RI
report and will include a health risk assessment for workers and
the public.
                      6.2   ENVIRONMENTAL RISKS

Surface water and sediment samples collected  from Prickly Pear
Creek indicate the presence of contamination.  Contamination from
Prickly Pear Creek migrates to nearby Lake Helena, which was
previously used for commercial whitefish farming.  Endangered
species, particularly bald eagles, and  critical habitats have been
identified in the Helena Valley, and may be threatened by exposure
to contaminants migrating from the Asarco site.  Upper Lake,
adjacent to the smelter site, supports  habitat for numerous
migratory waterfowl and supports limited recreational fishing by
Asarco personnel.  The potential for continued contaminant leaching
from sediments and soils for the various contaminant source areas
                                6-13

-------
 into the groundwater and surface water poses a j.ong-term threat  to
 the environment.  Seepage and leakage from the process ponds are
 evident and impacts have been recognized.  Seepage from Lover Lake
 impacts on the water quality at Prickly Pear Creek.  The water
 quality of Prickly Pear Creek is already in violation of surface
water quality standards intended to protect fish and aquatic
wildlife.

Environmental risks to animal and vegetation habitat and residents
were not quantified in the process ponds feasibility study.  These
risks, if present, will be quantified in the comprehensive RI/FS
report.  The Helena Valley area supports a wide diversity of plant
and animal habitat.  No endangered plant species are known to exist
in the Helena Valley.  However, there is the possibility for
endangered birds, particularly migratory bald eagles (Haliaeetus
leucocephalus) and peregrine falcons (Falco peregrinus), to travel
through the Valley.  There is also the potential for these birds  to
nest because of suitable habitat that is presently unoccupied.
Eagles and falcons have been observed in the Sleeping Giant-Hauser
Lake area (BLM, 1983:  U.S. EPA, 1987).

Other wildlife consists of both game and non-game  species
indigenous to west-central Montana.  Game species  of importance
include the white-tailed deer (Odocoileus virginianus), mule  deer
(0. hemionus), elk (Cervus canadensis), pronghorn  antelope
(Antilocar pa americana), both native and introduced trout  (Salmo
and Salvelinus spp.) hungarian partridge (Perdix perdix), ring-
necked pheasant (Phasianus colchicus), and  grouse  (Dandragapus  sp.,
                                6-14

-------
 Bonasa sp.).  Also present during certain periods are migrating
 waterfowl.

 The major vegetative rangeland types in the Helena Valley are foot-
 hill grasslands and Lodgepole pine/Douglas fir forests.  The foot-
 hill grasslands are at a higher elevation than the Montana plains
 grasslands and consequently receive more precipitation and produce
 more forage.  Lodgepole pine (Pinus contorta)/Douglas fir
 (Pseudotsuga menziesii) forest can be found on mesic north-facing
 slopes at intermediate elevations (U.S. EPA, 1987).
                          6.3   CONCLUSIONS

Fluids contained within the four process ponds exhibit high con-
centrations of some 18 to 20 elements that are hazardous
substances, including arsenic, cadmium, copper, lead, and zinc.
These elements have seeped into the soils and groundwater both on
and off the plant site.  Although the highest concentrations are
found underneath and adjacent to the four process ponds, the more
mobile elements, such as arsenic, have been transported by natural
groundwater movement into aquifers and soils underlying East
Helena.

Arsenic, because of its mobility relative to the heavy metals, and
because it is a human carcinogen, is the element of  greatest con-
cern in this analysis.  Monitoring wells shov that arsenic from  the
process ponds has migrated into East Helena at concentrations
                                6-15

-------
 greater  than 20 times the federal drinking water standard (maximum
 contaminant level) of 50 parts per billion.  Fortunately, such ele-
 vated  levels have thus far been found only in shallow groundwater.

 Because  the affected shallow aquifers are not a source of drinking
 water  in East Helena, there is currently no direct human exposure
 to arsenic through groundwater.  Nonetheless, the potential does
 exist  for human health risk to materialize if someday there is a
 need to  tap into shallow aquifers for drinking water, or if the
 arsenic  migrates into deeper aquifers.

 Environmental risks associated with seepage and leakage from the
 process  ponds are already a problem.  Seepage from Lower Lake into
 Prickly  Pear Creek adds to existing violations of water quality
 standards caused by mining leachate entering the creek upstream of
 the smelter.  These water quality standards are intended to protect
 fish and aquatic wildlife.  In addition, seepage from Lower Lake
 and leakage from the acid plant water treatment facility and the
 speiss granulating pit and pond have introduced arsenic to the
 groundwater under East Helena.

 The remedial actions presented in this ROD will remove future
 contact  between process fluids and underlying soils  and ground-
water.   Such source removal is a vital first step in reducing the
 potential human health risks and current environmental risks dis-
 cussed above.  Still, source removal is only the first step.  The
 Comprehensive RI/FS report will address problems associated with
                                6-16

-------
the contaminated soils and groundwater under East Helena, which is
beyond the scope of the Process Ponds RI/FS.

The risks identified in the Endangerment Assessment (EA) component
of the FS were briefly summarized in this section.  The remedial
actions presented in the following chapters of this ROD should
alleviate the risks identified in the EA.  Actual or threatened
releases of hazardous substances from this site, if not addressed
by implementing the response action selected in this ROD, may
present an imminent and substantial endangerment to public health,
welfare, or the environment.
BOIT727/006.50/jms
                                6-17

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               7  DESCRIPTION OF ALTERNATIVES

During the Feasibility Study, Asarco developed more than 200
potential cleanup alternatives.   The alternatives were com-
pared to one another in terms of their effectiveness,  imple-
mentability, and cost.  Alternatives judged to be most
promising on the basis of these  three screening factors were
retained for detailed analysis in accordance with the NCP.
These alternatives were also evaluated based upon their
expected compliance with the following nine criteria:

     •    Protection of human health and the environment

     •    Compliance with legally applicable or relevant and
          appropriate requirements (ARARs)

     •    Reduction of toxicity, mobility, and volume

     •    Short-term effectiveness

     •    Long-term effectiveness and permanence

     •    Implementability

     •    Cost

     •    Community acceptance
                             7-1

-------
      •    State acceptance

The alternatives described in this ROD best meet the above
criteria and, at the same time, provide a reasonable range
of cleanup options for addressing the source contamination
problems in the four process ponds.  In some cases, alterna-
tives were combined to provide greater assurance that the
essential criteria will be met in this cleanup.  All of the
engineering estimates presented in this chapter, including
assumptions concerning site characteristics, are based on
the September 1989 process ponds FS developed by Asarco.
However, the volumes of soils and sediments to be excavated
will be greater than what was presented in the FS because
deeper excavation is needed to assure effectiveness and pro-
tectiveness.

The Superfund program requires consideration of a "No
Action" alternative at every site.  Under the No Action
alternative; contaminated material would be left as is; how-
ever, the EPA could require warning signs, or land use
restrictions, or continuous monitoring of the affected soil
and water.

All of the alternatives summarized below and shown in
Table 7-1, except No Action, involve soil or sediment
removal.  Because the soils and sediments underneath and
adjacent to the process ponds show elevated arsenic and
heavy metals concentrations down to the groundwater-bearing
                             7-2

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                                                 Table  7-1
                                           8PECFC ACTIONS FOR
                                             EACH ALTERNATIVE
AftCA





IMCH
i2r <^





______
|£DM
POM) AND <
SPCUJ PIT

ADD Pi ANT
THCATIeCNT ^|
r ACQUIT

MT* •
- Replace lover lake milt lonkt at the primorv holding toc*ly.
emergency conloinmenl ol storm runoll.
OlepoM al 50- 70 gpm gain In main pracett fluid circuit and -oler tiered
In lower lake Uwougti evaporative processes of planl.
Remove Mdbnenle «llh high metals concentrollont by dredge. drogMne.
and/or Industrial vacuum Dry eedimenl lor handling and disposal.
Treol/dispOM el eedimcnle in •metier process
Dispose al sediments in e noiordout watte locWIy
Dispose of sediments In e hoiordout watte lociMy lo be constructed in
the Cast Helena area
Treatment ol Lower lake procett tuldt and discharge In Cost Helena
publicly owned sewage treatment plant
Treatment el Lower lake procett *uldt and ditcltarge In Prickly Pear
Creek (requires NPOCS permit)
Treolmenl ol process 00101 in place by copreclpilolion Remove
precipitate with tedimenlt alter treatment Is complete
~ Replace tils 1 Ing pond »IUi lank and secondary conloinmenl focllly.
Replace e.isling tpeitt gronuloling pit with o new Uned lacMly.
Upgrode Cirslmg pit by treatment ol e«rsling concrete and/or reptocemenl
ol existing concrete.
C-co«olion ol toile with high metals cancentrollone. A li»e loot bulfer
_ lone around the perimeter ol replaced lacWllet •• be eicaooled.
~ Replace main MllUng pond vllh lonk(t) end secondary leak conloinmenl
locllly Line tedntcnl drying area lo stop taflllrolion ol Aulds
la ground»oler Replace eiitling dumpslcrt vilh corrosion resistant
Milling dumptlert Replace nooden fraught -llh o corrosion rcslslonl
Kuid transport network Undertvic dumpslcr pad with cloy or o
geamembrane and replace concrete pod
Line c-ltllng tcllUng pond.
Replace emitting pond and settling dumpslcr system with closed circuit
Miration Ireolmcnl system
e.covolian ol contaminated toilt Treat and dispose ol sediments In
_ smeller process
iCicovolc ballom scdimcnlt by bockhoe Treat and dispoje c^> smeller
process Line lormcr pond -ilh cloy or other liner il pond i^^^knded for
use o» on emeiqency holdinq loc*.ly ^^^B





•


•
















•



•
















•

•






•











•
•













•


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•
•

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•

•
•




















•


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*
•

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•
1



















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-------
 gravels  (at  approximately 20 to 22 feet), it may be argued
 that  excavation should be done to that depth.  However, con-
 centrations  of arsenic and metals in soils and sediments are
 greatest in  the uppermost few feet and they decrease as
 depth increases.

 In any feasibility study involving contaminated soils, the
 question of  how much contamination may be left in place is a
 perplexing one.  In the case of Lower Lake, it would be
 necessary to remove about 18 feet of wet sediments over a
 7-acre area  (180,700 cubic yards) to eliminate all arsenic-
 and metals-laden sediments.  There is no assurance that
 removing all sediments is more effective than removing the
 uppermost 3  to 4 feet.  In addition, the cost of removing
 all of the contaminated sediments is prohibitive
 (approximately $78 million).

 The results  of soil leach (EP toxicity) tests may provide a
 reasonable alternative to complete removal of sediments.
 These tests examined the potential of arsenic and metals for
 leaching from soil as water comes into contact with them.
 The leachate was collected from test soil samples and
 analyzed to  see if it had picked up or dissolved the
elements bound in the soil.  These tests were run on soils
and sediments from all process ponds except former Thoraock
Lake.  Concentrations of arsenic and metals in the test
leachate varied among the soil samples but analysis showed
that at some soil depth (except for soils under the acid
                             7-4

-------
 plant) leachate produced in these tests meets federal
 drinking water standards.

 With  that concept as the basis for determining the minimum
 extent to which soils and sediments should be excavated,
 many modifications of the alternatives were developed to
 examine whether other important factors might require deeper
 excavation.  State water quality standards, which are more
 stringent than federal drinking water standards, were
 examined, as were technical practicability and sheer soil
 volume.

 There may be residual contamination in the remaining sedi-
 ments and soils that could potentially impact the ground-
water.  For all alternatives, a groundwater and surface
water monitoring plan for all areas of the process ponds
will be implemented during the remedial design phase to
verify the effectiveness of excavation and other remedial
 actions.
              7.1  ALTERNATIVES FOR LOWER LAKZ

There are five alternatives for Lover Lake, including No
Action (refer to Table 7-1).  All the alternatives  (except
No Action) contain common actions.  The actions comprising
alternatives are described in detail followed by a  descrip-
tion of alternatives and a presentation of the applicable or
relevant and appropriate requirements (ARARs).
                             7-5

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    .  NO ACTION

With the No Action alternative,  Lower Lake would  continue
be used as the primary settling and runoff  storage pond.
Seepage of process fluids and potential leaching  of arseni
from the lake bottom sediments would continue.

7.1.2  ALTERNATIVE 4A

Alternative 4A involves the following actions:

     •    Replace Lower Lake with tanks

     •    Treat process fluids and discharge to the East
          Helena Sewage Treatment Plant

     •    Excavate and dry sediments               •

     •    Smelt sediments in smelter process

     •    Construct a lined pond for storm runoff

Lover Lake currently functions as the main process fluid
circuit settling pond and provides storage of rainfall and
snowmelt runoff from within the plant.  Under Alterna-
tive 4A, two large steel tanks would replace Lower Lake as
the plant's primary water holding facility, and  a lined pond
                             7-6

-------
 or  additional tanks would be constructed in tne northwest
 corner of the property for emergency containment of storm
 runoff.

 The tanks would be sized at 1,000,000 gallons each to allow
 one day's operation on one tank while cleaning the other.
 Accumulated sediments would be periodically suctioned out
 and reprocessed.  The tanks would be similar in design to
 Thornock Tank, which has a leak detection and secondary con-
 tainment system.  The potential location for the tank is
 near existing Lower Lake (see Figure 7-1).

 Effluent from the process water treatment plant would be
 discharged to the East Helena sanitary sewer system, a
 publicly-owned treatment works (POTW).  Pretreatment
 standards for discharge to the POTW would be developed
 before remedial design of an onsite pretreatment facility.
 The EPA, state, and local community would follow the federal
 effluent guidelines (40 CTR. 421.72, in part) in developing a
 community pretreatment program for the constituents of
 concern.

Achieving the effluent standards established in that process
will require construction of a water treatment facility  at
 the plant to reduce metals and arsenic concentrations in
plant wastewaters prior to discharge.  The plant would
provide 2-stage treatment.  Typical treatment would be to
 first remove arsenic by co-precipitation.  Metals would  then
                             7-7

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                                   L_
. ^     Proposed Tank
        Location
            Figure 7-1
            Proposed Locations for Steel Tant
            and a Runoff Replacement Pond

-------
 be  removed by raising the pH and neutralizing.  Capacity of
 the treatment plant is estimated to be between 20 and
 100 gpm.  Costs and implementation time for alternative 4A
 are shown in Table 7-2.

 Excavation of sediments would be performed to remove the
 artificially deposited sediment and sludge layer (approxi-
 mately 1 to 3 feet) at the bottom of Lower Lake.  The EPA
 has  classified such bottom deposits in surface impoundments
 at  all lead smelters as hazardous waste; therefore, they
 must be removed and treated or safely disposed.

 Based on information obtained from soil leach (EP toxicity)
 tests, water coming into contact with sediments found at the
 lower limit of the artificially deposited layer may not meet
 federal primary drinking water standards.  A key modifica-
 tion to this alternative would require excavation of an
 additional 2 feet below the artificially deposited sediment
 and  sludge layer.  This modification provides a margin of
 safety and it offers greater assurance that Lower Lake
water, once treated, may meet federal drinking water stan-
 dards after coming into contact with the remaining sediments
 (refer to Figure 5-1).

The  sediments from Lower Lake would be removed by  suction
dredge or dragline and placed in a lined facility  at the
 south or west edge of the plant to dry.  Because of the
width of the lake, dredging with a small floating  suction
                             7-9

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                                      Table  7-2

           COSTS AND IMPLEMENTATION TIMES  FOR REMEDIATION ALTERNATIVES


Area


Lower L«ke



Spelae Oranulatlng
Pond end Pit
Acid Plant
Meter Treetment
facility
Former Tfaornock Lake


Alternative
No Action
4A
4B
40
4E
5S
8B«7E
8B»7H
11D
HE
HP
14
Capital
Cost
($)
0
8.520.600
8,566,100
8,520,600
9,731.200
3,538,600
649,400
590,500
1,865.500
1.746,700
1,927.000
19,000
Annual
OfcN Cost
($)
0
734,300
756,300
2,577,600
217,800
621,600
6,600
2,200
5.500
525
33,000
0
Present
Worth
($)
0
12,729,700
13,113,400
17,749,400
12,904.900
6,015,300
750,900
624,300
1,958,500
1,754,800
2,859,300
19.000
Implementation Time
Excluding Smelting of
Sedlmente end flolle (TRS)
0
5
5
48
4 a
5
2b
2
2
2
2
-5
.Alternatives 4D and 4E  do not Involve smelting of excavated sedlmenta,
  Remediation of the Spelaa Pit may be delayed 12 to 18  months.

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 puxap (hydraulic Mud Cat type) would be more feasible than
 removing material using a  shore-based dragline or clamshell.
 Additionally,  a dragline would require hauling of material
'from Lower lake to the drying area.  A dredge can pump
 material directly to a drying area; thus, hauling is
 unnecessary.

 The  volume of  sediments requiring  removal is estimated  to be
 the  area of the pond (7 acres), by 4 feet deep.  This
 includes an average of 2 feet of artificially deposited
 sludge  plus 2  feet of contaminated natural  sediments as a
 safety  margin  for removal.  Based  on this requirement,  the
 total volume is estimated  to be 45,000 cubic yards wet. The
 solids  content of the sediment is  about  40  percent.  The es-
 timated dry volume of the  sediment would be 18,000 cubic
 yards or 27,000 tons.

 The  tentative  size of the  drying area  is 2.4 acres at  a
 depth of 1 foot.   This will allow  drying for about
 3,900 cubic yards of wet material. Evaporation  data at the
 plant for 1987 indicate that about 0.25  in./day  of net
 evaporation occurs from May through September.   A conserva-
 tive drying time for 5,600 cubic yards of material would
 therefore be about 60 days.  At three  drying periods per
 year, 3 years  may be required to remove  the sediments.
 After drying,  the material would be smelted in  the  smelter
 process.
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The drying area would consist of a 325- by 325-foot concrete
pad underlain by 12 to 18 inches of sand with a leakage
detection and secondary collection system.  This system
would be underlain by a geomembrane liner.

After drying, and before smelting, sediments would be tem-
porarily stored in the new ore storage building.  Sediments
would be smelted as part of normal smelter operations.
Smelting would enable Asarco to recover small amounts of
lead and other metals contained in the sediments; but more
importantly, it will immobilize the remaining arsenic and
metals within the slag produced in the process
(vitrification).  The excavated and dried sediments would be
handled like ores to prevent fugitive emissions.

A proposed containment pond at the northwest corner of the
East Helena plant would replace Lower Lake as a containment
facility for excess storm runoff water (see Figure 7-1).
The northwest location provides the following advantages:

     1.   Elimination of pumping for storm water runoff.
          Since the plant area topography slopes to the
          northwest, all runoff from the plant would  flow by
          gravity to the proposed pond.  This would
          eliminate pumping storm water that occurs now  in
          the plant.
                            7-12

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     2.   Favorable construction conditions.   The soft
          saturated sediments of Lover Lake and large
          dewatering demands during construction reduce the
          technical feasibility of lining this pond.  The
          proposed northwest pond location is approximately
          30 feet above the water table and has soils suit-
          able for construction of a lined facility.

The proposed pond construction would consist of a primary
geomembrane liner underlain by a secondary leachate monitor-
ing and collection system which in turn would be underlain
by a secondary geomembrane liner.  The pond would be
designed to contain all plant runoff from the 100-year, 24-
hour storm event (assuming 95 percent paved conditions with-
in the plant).  Currently only about 40 percent of the plant
area is paved; however, the pond has been sized to contain
potential runoff if 95 percent of the plant area is paved.

The required storage capacity for the designed pond is
approximately 4.75 million gallons.  Rough dimensions of the
pond using available space are 600 feet by 200 feet with a
total depth of about 6.5 feet.  Runoff that would accumulate
during a major storm is expected to evaporate within  1 or
2 years and sediments would be reprocessed.
                            7-13

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 7.1.3  ALT   IATIVZ 4B

 Alternatives 4A and 4B are alike in that they share common
 actions.  Differences are in the methods utilized to handle
 treated process water.  As for Alternative 4A,
Alternative 4B would replace Lower Lake with steel tanks,
provide a lined facility to contain excess storm runoff,
dredge the lake to remove sediments, dry the sediments, and
process the sediments in the smelter operation.  For
Alternative 4B, excess process water would be treated to
 remove metals and arsenic, then discharged to Prickly Pear
Creek.

Discharge of treated process water to Prickly Pear Creek
would be required to meet the substantive requirements of a
Montana Pollutant Discharge Elimination System (MPDES)
permit if discharge occurs onsite.  If discharge occurs
offsite, procedural requirements would also have to be met.
Typical treatment would be as described for Alternative 4A,
except that treatment effluent standards may be more
stringent than those developed for discharge to the POTW.
Costs and implementation time for Alternative 4B and  for
other alternatives are shown in Table 7-2.

7.1.4  ALTERNATIVE 4D

For Alternative 4D, Lower Lake sediments would be  hauled  and
disposed at an approved RCRA hazardous waste  facility.  The
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closest facility is located near Salt Lake City,  Utah;  a
distance of about 500 miles.  Sediment would be transported
in gondola-type (20-ton) containers.

Alternative AD shares remedial actions described for Alter-
native 4A, except for the handling of Lower Lake sediments.
This alternative would replace Lower Lake with steel tanks,
provide a lined facility to contain excess storm runoff,
dredge the lake to remove sediments,  dry the sediments, and
discharge treated excess process water to the East Helena
POTW sewage treatment lagoons.  In Alternative 4D, sediments
would be transported and disposed at an approved RCRA
facility.  Costs and implementation time for Alternative 4D
are shown in Table 7-2.

7.1.5  ALTERNATIVE 4E

Alternative 4E is essentially the same as Alternative  4D,
except that sediments from Lower Lake would be disposed in a
permitted hazardous waste landfill close to the plant.  Con-
struction would be preceded by a site survey to determine
soils and water table conditions.  Approximate size of the
facility would b« 250 feet by 250 feet by 9 feet deep.  The
landfill would be constructed to include a double membrane
liner, a leakage detection system, and a secondary collec-
tion system.  Based on available soils and geological  data,
the most favorable locations would be 1 to 2 miles south of
the smelter site.  In this area, groundwater is reported to
                            7-15

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be in excess of loo feet below the ground surface and is
overlain by 45 feet of low permeability volcanic ash tuff
(Hydrometrics, 1988b).  This is probably the same ash tuff
unit that underlies the East Helena Area.  Costs and imple-
mentation time for Alternative 4E are shown in Table 7-2.

7.1.6  ALTERNATIVE 5S

Alternative 5S is essentially the same as Alternative 4A,
with one major exception:  process waters in Lower Lake
would be treated in-place rather than discharged to either
Prickly Pear Creek or the POTW, and evaporative processes of
the plant would be used to treat the 50 to 70 gpm gain in
the process fluid circuit.

Prior to treatment of the process waters, two large tanks
would be installed to replace Lower Lake as a process pond
as in Alternative 4A, and a lined pond or additional tanks
would contain any unexpected runoff.  The bottom sediments
would be excavated in the same manner as for the key modifi-
cation of Alternative 4A; that is, excavation would extend
to 2 feet below the artificially deposited layer.

The in-place treatment of Lover Lake process waters would
involve batch treatment with excess concentrations of ferric
chloride to precipitate arsenic and other metals.
                            7-16

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Treatment standards for in-place coprecipitation of arsenic
and metals have been established by the EPA.b  The  require-
ments for arsenic, cadmium, copper, lead,  and zinc are 0.02,
0.01, 0.004 to 0.008, 0.05, and 0.11 mg/L, respectively.  It
is required that in-place coprecipitation result in con-
centrations of metals at or below these requirements.

After treatment, water would be left in place or possibly
discharged.  Precipitate would accumulate on the pond bottom
and would be removed by dredge along with the Lower Pond
bottom sediments as described for Alternative 4A.  The
removed precipitate, along with the bottom sediments, would
be dried and smelted, as described for Alternative 4A.

Evaporation processes to reduce gains in the proces circuit
would be implemented after the installation of storage tanks
and removal of Lower Lake from the main process fluid
circuit as described in Alternative 4A.  The existing gain
in the main process fluid circuit is estimated at  50 to 70
gpm.  The following actions would address the main process
fluid circuit gains:

     1.   Removal of groundwater collected in the  drainline
          near the existing ore storage and mixing area from
          the main process fluid circuit.  Pumping collected
*Refer to Chapter 10,  "Statutory Determinations," for
descriptions of these standards and the basis for their
selection.
                            7-17

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     groundwater from a collection sump  into  the main
     process fluid circuit would be terminated  and  the
     lower basement of the existing ore  storage and
     mixing area would be allowed to flood (returned to
     a state of equilibrium with the normal groundwater
     level).  This action would cause the groundwater
     level to rise approximately 2 feet  and reduce
     gains to the main process circuit by 30 to 40  gpm.

2.   Removal of potable water input from freezing pre-
     vention bleeders.  This action would be accom-
     plished by:

     a.   Rerouting potable water bleeders to the  sani-
          tary sewer system

     b.   Heating trace potable water lines so bleeder
          lines are no longer necessary

     c.   Replacing the existing potable water supply
          with bottled water

3.   Elimination of the remaining gains  in the process
     fluid circuit by existing evaporative processes
     within the plant or by new methods  of evaporation
     developed using waste heat from the smelter pro-
     cesses are being evaluated.  Vastewater from the
     change house is the remaining source of gains to
                       7-18

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          the main process circuit.   Sources of this waste
          water are the laundering facilities and personnel
          showers.  An estimated 10  to 20 gpm is generated
          from these sources.

          An additional output to Lower Lake that also needs
          to be eliminated is  the acid plant blowdown
          coolant water.  Flow in this circuit averages
          about 9 gpm but has  occasional short flow peaks
          (20 minutes) up to 120 gpm.

          Cooling towers that  are a  part of the smelter fac-
          ility are a potential source of fluid elimination.
          Consumption of water for this facility varies sea-
          sonally from a low of about 5 gpm to a high of
          about 25 gpm.  Additional  evaporative devices and
          methods are.currently being investigated.

Costs and implementation time  for Alternative 5S are shown
in Table 7-2.

7.1.7     APPLICABLE OR RELEVANT AND APPROPRIATE REQUIRE-
          MENTS (ARARJ) AND SEDIMENT CLEANUP OBJECTIVES FOR
          LOVER LAKE ALTERNATIVES

The Occupational Safety and Health Administration  (OSEA)
requirements for sediments handling would be the same as  for
routine smelter operation.  Ambient Air Quality Standards
                            7-19

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 for  smelting sediments, the same as for smelting ore,  are
 expected to be met once the new State Implementation Plan
 for  reducing emissions takes effect.  Ambient Air Quality
 Standards for airborne lead in the proposed sediment drying
 area also are expected to be met.

 Disposal actions under Alternatives AD and AE would require
 that the hazardous waste disposal facility be licensed under
 Resource Conservation and Recovery Act (RCRA) regulations.
 Disposal of sediments would be in accordance with RCRA regu-
 lations; Alternative AE would require RCRA permitting.

 Process fluids pretreatment for discharge to the East Helena
 POTW (Alternatives AA, AD, and AE) is expected to meet most
ARARs.  However, meeting the State's more stringent water
 quality standards for long-term protection of aquatic life
would be technically impracticable.  Waivers of those ARARs
would be justified on the basis of technical
 impracticability.

The water treatment component of Alternative 5S will meet
prescribed standards for in-place treatment of process
 fluids.  The proposed in situ treatment process has not  been
proven on a large scale.  If the in situ treatment method
proves to be ineffective, the contingency remedy will be
invoked at which time pretreatment standards for discharge
of treated Lover Lake waters into the East Helena POTW will
be identified for the constituents of concern.
                            7-20

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    Lower Lake alternatives involve the same cleanup objec-
 tive ^^r excavation of sediments.  The depth of sediment
 excavation, which will be 2 feet beyond the lower limit of
 the artificially deposited sediment layer, was determined,
 in part, by the results of EP toxicity tests (the ability of
 the leachate to meet federal drinking water standards at
 some depth) and, in part, costs.  Drying areas will be con-
 structed in accordance with the substantive requirements of
 RCRA.
  7.2  ALTERNATIVES  ?OR THE SPEISS GRANULATING  POND AND  PIT

The  following are detailed descriptions of remediation
alternatives for the speiss granulating pond and pit.
Within each alternative (except No Action) are individual
actions and combinations of actions that together will meet
remediation goals.  Costs and implementation times for
speiss granulating pond and pit alternatives are shown  in
Table 7-2.

7.2.1  NO ACTION

With the No Action alternative the speiss granulating pond
and pit would continue to be used as under current
operations.  Existing conditions would remain.  This alter-
                            7-21

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 native would incur no additional operational or capital
 costs.

 7.2.2  ALTERNATIVE 8B+7E

 Alternative 8B+7E involves the following actions:

     •    Replacement of existing pond with tank and secon-
          dary containment facility

     •    Replacement of existing pit with a new lined
          facility

     •    Excavation of contaminated soils

 In Alternative 8B+7E, a steel tank with a liner, leak detec-
 tion system, and secondary containment and recovery capabil-
 ity would replace the existing speiss granulating pond (see
 Figure 7-2).  The tank would be constructed at an elevation
 to allow gravity draining of the speiss granulating pit.
Accumulated sediments in the tank would be periodically
 suctioned out and reprocessed.

The current speiss granulating pit is constructed of con-
 crete and normally contains water with elevated  arsenic and
metals concentrations.  The pit would be replaced with a
watertight facility constructed of concrete with a steel
 liner.  According to Asarco's process engineers, pit
                            7-22

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                                      Existing Speiss
                                     Granulating Pond
                                      (To be removed)
Speiss Granulating
   Settling Tank
    (Proposed)
                                           New 8" Suction ?
                                  \
                                                                   Crossing Plant •
                                     Dewatering Bins
                                       (Proposed)

                                                           Speiss Granulating
                                                                   Pit
                                                               (Proposed)
                                                          Figure 7-2
                                                          Proposed Speiss Granulating Pit
                                                          and Pond Replacement Facilij

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 replacement may require interruption of plant operations-for
 about 30 days.  The pit would be allowed to drain by gravity
 to the speiss pond when the speiss pit is not in use.  A
 lined secondary leak detection and recovery system would be
 included.

 During construction of these replacement structures, soils
 underneath and adjacent to the existing pond and pit would
 be excavated and set aside for smelting later.  Prior to
 smelting, the same precautions against fugitive emissions
 that are afforded the ore piles would apply to the soils.
 Large cobbles and boulders would be separated from the soil,
 washed, and stored onsite, thus reducing the amount of
 material required for smelting and hence the time required
 to smelt the soils.

 The cleanup objectives based on EP toxicity test data, will
 be excavation of soils with leachate concentrations exceed-
 ing MCLs, or excavation to maximum practical limits
 (approximately 20 feet).  These objectives may require addi-
 tional soil core sampling at the speiss granulating pond and
 pit.

Although EP toxicity tests indicate that leachate from soils
 at a depth of 6 feet may meet federal drinking water stan-
 dards, excavation to the groundwater table (approximately
 20 feet)  is recommended to avoid potential conflicts with
 future construction activities in the area.  For example,
                            7-24

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 new  structures will be built in the area once excavation
 cavities are refilled.  Excavation to the groundwater table
 will provide a margin of safety which will decrease the
 likelihood of a need for future excavation in the area and
 subsequent disassembly or moving of future structures.
 Because of the relatively small area of the speiss granulat-
 ing pond and pit, deep excavation will not require substan-
 tially greater cost than excavation to a depth of 6 feet.

 Excavation will include a 5-foot buffer zone outside of the
 perimeter of removed portions of the pond and pit
 facilities.  -Although soils outside this zone are potential
 sources of arsenic and metals to groundwater, 5 feet is con-
 sidered the practical areal limit associated with the speiss
 pond and pit installation.  Soils outside this zone will be
 addressed as part of the groundwater and surface soil
 operable units in the Comprehensive Feasibility Study.  Soil
would be smelted as described for Lower Lake alternatives.
 Sediment removal will occur in conjunction with speiss pond
 and pit replacement.

The estimated volume of material to be removed from the
 speiss pond and pit area as part of this alternative  is
 3,700 cubic yards and includes the area 5 feet around the
pond and pit perimeter excavated to a depth of approximately
20 feet.
                            7-25

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 new  structures will be built in the area once excavation
 cavities are refilled.  Excavation to the groundwater table
 will provide a margin of safety which will decrease the
 likelihood of a need for future excavation in the area and
 subsequent disassembly or moving of future structures.
 Because of the relatively small area of the speiss granulat-
 ing pond and pit, deep excavation will not require substan-
 tially greater cost than excavation to a depth of 6 feet.

 Excavation will include a 5-foot buffer zone outside of the
 perimeter of removed portions of the pond and pit
 facilities.  Although soils outside this zone are potential
 sources of arsenic and metals to groundwater, 5 feet is con-
 sidered the practical areal limit associated with the speiss
 pond and pit installation.  Soils outside this zone will be
 addressed as part of the groundwater and surface soil
 operable units in the Comprehensive Feasibility Study.  Soil
would be smelted as described for Lower Lake alternatives.
 Sediment removal will occur in conjunction with speiss pond
 and pit replacement.

The estimated volume of material to be removed from the
 speiss pond and pit area as part of this alternative  is
 3,700 cubic yards and includes the area 5 feet around the
pond and pit perimeter excavated to a depth of approximately
20 feet.
                            7-25

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 7.2.3  ALTERNATIVE 8B+7H

 For Alternative 8B+7H, as with Alternative 8B+7E, the speiss
 granulating pond would be replaced by a steel tank with a
 liner, leak detection system, and secondary containment and
 recovery capability.  In this alternative, the pit would be
 repaired rather than replaced.  Repairs would be performed
 to eliminate leakage and would include a leak detection
 system and secondary containment capability.  A liner would
 be placed between a new insert and the existing concrete
 floor and walls.  Plant operations could continue uninter-
 rupted.  Although soils excavation in the pond area would be
 conducted similar to that described in Alternative 8B+7E,
 the excavation of soils beneath the pit would not be
 possible in this alternative.

 Repair of the speiss granulating pit would include relining
 the pit with concrete to make it watertight and to improve
 the drainage.  Presently, about 4 to 6 inches of water are
 contained in the pit constantly.  Relining the pit with
 concrete would allow complete drainage and reduce the resi-
 dence time of water in the speiss pit to about 45 to 60
minutes per day.  An alternative to lining the pit with  con-
 crete would be to construct a steel insert and place it  in
 the existing structure.  A steel liner would be more
durable, is less likely to be damaged by hauling equipment,
and therefore would provide a greater safety margin against
 leaks than concrete.
                            7-26

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 7.2.4     APPLICABLE  OR RELEVANT AND APPROPRIATE REQUIRE-
           MENTS  (ARARs) AND SOIL CLEANUP OBJECTIVES FOR
           SPEISS  GRANULATING  POND AND PIT ALTERNATIVES

 Ambient Air  Quality Standards  for smelting soils, the same
 as  for smelting ore,  are expected to be met once the new
 State Implementation  Plan  for  reducing emissions takes
 effect.  The OSHA requirements for  soils handling would be
 the same as  for routine smelter operation.

 The soil cleanup  level for the speiss granulating pond and
 pit alternatives  is similar to those described  for Lower
 Lake.  Based oh information obtained from EP toxicity tests,
 leachate produced meets federal drinking water  standards  for
 soils at and below depths  of  about  6 feet.  However, exccva-
 tion of soils  to  20 feet provides a margin of safety which
 will decrease  the likelihood  of a need for future excavation
 in  the area  and subsequent disassembly or moving of future
 structures.
7.3  ALTERNATIVES FOR THE ACID PLANT WATER TREATMENT FACILITY

The purpose of the acid  plant water  treatment  facility is  to
reduce the solids content  of the  scrubber  blowdown water and
to treat and supply water  to the  sinter  plant.   Because of
moisture in the  atmosphere and  feed  stock,  the  scrubbers
produce an excess of water.  Part of this  water is recircu-
                             7-27

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 lated to the scrubbers and part is neutralized and pumped to
 the sinter plant.  Areas of primary concern in the acid
 plant water treatment facility are the dumpsters and the
 main settling pond which provide gravity settling for blow-
 down water before it is neutralized and returned.  Typical
 pH of blowdown water prior to neutralization is 1.3 to 1.9.
 The following are detailed descriptions of remediation
 alternatives for the acid plant water treatment facility.
 Within each alternative are individual actions and combin-
 ations of actions that together will meet remediation goals.
 Costs and implementation times for acid plant water treat-
 ment facility alternatives are shown in Table 7-2.

 7.3.1  NO ACTION

 For the No Action alternative, no action would be taken.
 The existing condition of the main settling pond, dumpster,
 fluid transport troughs, and the sediment drying area would
 remain.  No additional work would be conducted.

 7.3.2  ALTERNATIVE 11F

Alternative 11F would remove the settling pond, dumpster
 system, and sediment drying area and replace them with an
enclosed, aboveground mechanical separation system.  The new
system would include cyclone separators and a clarifier with
tube settlers.  The system would include leak detection  and
secondary containment features.  Accumulated sediments would
                            7-28

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 be  periodically suctioned out and reprocessed.  Existing and
 proposed sediment-drying areas would be equipped with liners
 and containment capability.
    /
 Presently, all water is neutralized before leaving the
 treatment plant.  The new process would neutralize only
water that is pumped to the sinter plant.  Scrubber makeup
water would not require treatment beyond simple solids
 removal.

With the existing settling basins and lines removed, excava-
 tion of underlying and adjacent soils would proceed.  The
 cleanup objectives, based on EP toxicity test data, will be
 excavation of soils with leachate concentrations exceeding
MCLs, or excavation to maximum practical limits (approx-
 imately 20 feet).  These objectives may require additional
 soil core sampling at the acid plant water treatment
 facility.

Results of past soil leach tests indicate that soils under-
lying the acid plant water treatment facility should be
excavated down to the coarse, groundwater-bearing gravels
 (approximately 20 feet).  This is based on the knowledge
that soils under the acid plant water treatment facility
exhibit characteristics of EP toxicity throughout the soil
profile.  The leachate from these tests fails to meet
federal drinking water standards, regardless of soil depth.
Because of the acidic condition of the soils, lime will be
                            7-29

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 added prior to replacement with fill to reduce mobility of
 arsenic and metals associated with acidic soils underlying
 the  acid plant water treatment facility.

 It is estimated that approximately 6,250 cubic yards of soil
 would be excavated; however, the actual volume will not be
 known until additional sampling is conducted in the remedial
 design phase and actual excavation is underway.  Excavated
 soils that exhibit characteristics of EP toxicity will be
 temporarily stored within the new ore storage building or in
 an area that is sufficiently secure to handle hazardous
 waste.  Excavated soils that do not exhibit characteristics
 of EP toxicity will be temporarily stored alongside the ore
 piles and treated as ores are treated to prevent fugitive
 emissions.  All excavated soils will be smelted in the
 smelter process, as described for Lower Lake sediments
 (Alternative 4A).  Large cobbles and boulders would be
 separated from the soil, washed, and stored onsite, thus
 reducing the amount of material required for smelting and
 the  time required to smelt the soils.

 7.3.3  ALTERNATIVE 11D

 Alternative 11D would involve excavation of contaminated
 soils, as described for Alternative  11F.  The existing
 concrete- or asphalt-lined tank would be replaced with  a
 freestanding steel tank with exposed side walls.  The  tank
would include a leak detection and secondary containment
                            7-30

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 system.  Also, jh« primary settling area consisting of  dump-
 sters would be relined with acid-resistant concrete. The
 sediment drying area would be double-lined and equipped with
 a secondary leachate detection and recovery system.  The
 drying area is assumed to be 100 feet by 100 feet and would
 be constructed using concrete underlain by sand and a PVC or
 high density polyethylene (HDPE) liner.  The existing steel
 dumpsters would be replaced with plastic or stainless steel
 containers.  The containers would be constructed to limit
 overflow of solute.  Also, the wooden trough system would be
 replaced with acid-resistant piping.  Although the existing
 neutralizing tanks would not be replaced, steps would be
 taken to eliminate or contain leakage.

 7.3.4  ALTERNATIVE HE

 Alternative HE is essentially the same as Alternative  LID,
with one exception:  the main settling pond would not be
 replaced.  Steps would be taken to eliminate leakage from
 the existing structure; a concrete basin similar to a
 swimming pool.  Excavation of soils under the main  settling
 pond would not be possible.  Excavation of soils from the
 area under the dumpsters would occur, as described  in the
modification of Alternative 11D.

The existing concrete pond would be lined with a flexible
geomembrane liner of PVC or HDPE.  The pond would be
drained, inspected for large cracks,  lined, tested  for
                            7-31

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 leaks,  and returned to service.  The existing dumpsters and
 trough  system would be replaced.  The dumpster area and
 sediment drying area would be lined as described in Alterna-
 tive  11D.

 7.3.5     APPLICABLE OR RELEVANT AND APPROPRIATE REQUIRE-
          MENTS (ARARs) AND SOIL CLEANUP OBJECTIVES FOR ACID
          PLANT WATER TREATMENT FACILITY ALTERNATIVES

Ambient Air Quality Standards, similar to those described
 for the speiss granulating area, are expected to be met.
OSHA requirements for soils handling would be the same as
 for routine smelter operation.  Tank design and construction
 (Alternative 11D) will meet RCRA requirements for leak
detection and secondary containment.  For Alternative HE,
the lining in the pond will meet RCRA requirements for leak
detection and secondary containment.

Soil cleanup objectives for soil removal at the acid plant
water treatment facility are similar to those described for
Lower Lake, except that soil leach  (EP toxicity) test
results indicate that the soils under the acid plant exhibit
characteristics of EP toxicity throughout the soil profile.
Therefore, the EPA recommends deep excavation at the acid
plant water treatment facility.
                            7-32

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         7.4  ALTERNATIVES FOR FORMER THORNOCK LAKE

In  1986, Thornock Lake was drained and replaced with a steel
tank, complete with a liner, leak detection system, and
secondary containment and recovery capability.  Dry sedi-
ments remain in the existing cavity.  The EPA has classified
these sediments of surface impoundments (including former
impoundments) at all lead smelters as hazardous wastes that
must be removed and treated or safely disposed.

7.4.1  NO ACTION

There are two alternatives for former Thornock Lake, includ-
ing No Action.  Under the No Action alternative, no further
work would be conducted on the sediments in former Thornock
Lake.  The existing sediment conditions would remain.  No
direct costs would be incurred if the sediments are left in
place.
          v
7.4.2  ALTERNATIVE 14

Alternative 14 consists of excavating the remaining bottom
sediments, stockpiling them temporarily, and  smelting  them.
Until the pond was abandoned in 1986, this was  the normal
procedure.  About 100 tons of sediment were reprocessed  in
the plant from each cleaning.  Sediments would  be  excavated
and smelted in the same manner as sediments from Lover Lake.
Depth of excavation would be determined as it was  described
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 for Alternative 4A  (for Lower Lake):  excavate to 2 feet
 beyond  the artificially deposited layer of sediments.  In
 the past, sediments were temporarily stockpiled alongside
 the ore piles, before smelting.  In this alternative, since
 these sediments are bottom deposits of a surface impound-
ments at a lead smelter, the EPA has classified them as a
hazardous waste.  Therefore, it will be necessary to
temporarily stock-pile the excavated sediments in the new
ore storage building.

Treating sediments in the smelter process would enable
Asarco to recover small amounts of lead and other metals;
but more importantly, it will immobilize the remaining
arsenic and metals within the slag produced in the process
 (vitrification).  A modification of this alternative is to
dispose of the sediments at a licensed hazardous waste
facility (refer to Alternatives 4D and 4E for Lower Lake).
The costs and implementation time for Alternative  14 are
shown in  Table 7-2.

7.4.3     APPLICABLE OR RELEVANT AND APPROPRIATE REQUIRE-
          MENTS (ARARa) AND THE SEDIMENT CLEANUP OBJECTIVES
          FOR FORMER THORNOCK LAKE ALTERNATIVES

Ambient Air Quality Standards for smelting  sediments,  the
same as for smelting ore, are expected to be met once  the
new State Implementation Plan for reducing  emissions takes
effect.
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The sediment cleanup objective for sediments in former
Thornock Lake is the same as that for Lower Lake.  The depth
of sediment removal will be 2 feet beyond the lower limit of
the artificially deposited sediment layer.  This alternative
is not expected to interfere with future remedial actions in
the area.
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            8  ALTERNATIVES COMPARATIVE ANALYSES

During the feasibility study,  Asarco developed more than 200
potential cleanup alternatives.   Alternatives were evaluated
according to the requirements  of the NCP.   In addition,
their expected compliance with nine essential criteria were
evaluated:

     1.   Protection of human  health and the environment

     2.   Compliance with legally applicable or relevant and
          appropriate requirements (ARARs)

     3.   Reduction of toxicity, mobility,  and volume

     4.   Short-term effectiveness

     5.   Long-term effectiveness and permanence

     6.   Implementability

     7.   Cost

     8.   Community acceptance

     9.   State and local agency acceptance
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 Four groups of alternatives were evaluated, one group for
 each area to be remediated:  Lower Lake, the speiss granu-
 lating pond and pit, the acid plant water treatment
 facility, and former Thornock Lake.  Each group of alterna-
 tives was evaluated separately.  Alternatives within each
 group were evaluated by the nine criteria and against each
 other.  For a comprehensive evaluation of alternatives,
 refer to the August 1989 Process Ponds Remedial Investiga-
 tion and Feasibility Study (RI/FS) report.
                       8.1   LOWER LAKE

8.1.1  PROTECTIVENESS, SHORT- AND LONG-TERM EFFECTIVENESS,
       AND PERMANENCE

All alternatives  (except No Action) reduce the risks from
metal- and arsenic-bearing Lower Lake fluids and sediments.
Risks to the community and to workers associated with the
implementation of these alternatives would be low.  Smelting
of excavated sediments would expose workers to metals and
arsenic at levels similar to those of routine smelting
activities.

The EPA has classified bottom sediments of surface  impound-
ments at all lead smelters as hazardous waste.  An  effective
way of treating this hazardous waste would be to dry the
material on lined pads, then dispose  of it in the smelting
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process (Alternatives 4A, 4B,  and 5S).   Smelting sediments
would allow recovery of small  amounts of metals, but more
importantly, smelting immobilizes residual metals and other
materials in slag.  This process would be similar to
vitrification.

During implementation of the alternatives, sediments would
remain as a potential source of groundwater contamination
until sediment removal is complete.  Even after excavation,
residual arsenic and metals in remaining sediments may
impact the groundwater.  The liner in the proposed storm
runoff containment pond would  be protective, but it might
break.  Continuous groundwater monitoring would be required
to verify that there is no leakage from the containment
pond.  The equipment life associated with these alternatives
is expected to be approximately 20 years.

Risk is involved with transporting contaminated sediments to
an offsite hazardous waste disposal facility (Alterna-
tive 4D).  The other Lower Lake alternatives do not incur
such risk.  However, Alternative 4E may pose some risk to
the community in that locating a hazardous waste landfill
near the City of East Helena increases the risk of
additional groundwater contamination, particularly  if the
landfill liner breaks.

Treatment of process fluids would protect human health and
the environment.  For Alternative 4B, the discharge of
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 process  fluids to Prickly Pear Creek would require treatment
 of  arsenic  and metals to bring levels to standards that
 would  be  specified by an MPDES permit.  For Alternative 5S,
 in-place  treatment of process fluids is expected to reduce
 arsenic and metals concentrations in the process fluids, but
 the technology has not been proven on a large scale.

 8.1.2  APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
       (ARARS)

 The Occupational Safety and Health Administration  (OSHA)
 requirements for sediments handling would be the same as for
 routine smelter"operation.  Ambient Air Quality Standards
 for smelting sediments, the same as for smelting ore, are
 expected  to be met once the new State Implementation Plan
 for reducing emissions takes effect.  Ambient Air  Quality
 Standards for airborne lead in the proposed sediment drying
 area also are expected to be met.  Drying areas will be con-
 structed  in accordance with the substantive requirements of
 RCRA.

 Disposal  actions under Alternatives 4D and 4E would require
 that the hazardous waste disposal facility be licensed  under
 Resource Conservation and Recovery Act (RCRA) regulations
 and CERCLA offsite policy.  Disposal of sediments  would be
 in accordance with RCRA regulations, and Alternative 4E
would  require RCRA permitting.
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 Alternative  5S will meet prescribed standards described for
 in-place  treatment of process fluids.  Large-scale applica-
 tions  of  the proposed treatment process have not been
 proven; therefore, a contingency remedy has been developed.
 The prescribed federal and state water quality standards are
 identified in Chapter 10, Statutory Determinations.  If the
 contingency  remedy is invoked, process fluids pretreatment
 will meet yet-to-be-determined standards for the con-
 stituents of concern.

 8.1.3  REDUCTION OF TOXICITY, MOBILITY, AND VOLUME

 Alternatives for Lower Lake would decrease mobility of the
 principal contaminants, arsenic and metals.  Compared to
 hazardous waste landfill disposal actions  (Alternatives 4D
 and 4E),  smelting sediments  (Alternatives  4A, 4B, and 5S)
would  reduce the volume of waste.  By smelting sediments,
 some metals could be recovered and residual hazardous metals
would  be  immobilized in the  slag.

 Both smelting and landfill sediment disposal actions would
 reduce the mobility of contaminants.  However, for the land-
 fill alternatives, if the liner in the hazardous waste land-
 fill breaks, contaminants could move into  the groundwater.

All process fluids treatment processes would reduce the
volume of contaminants.  Alternative 5S is expected to
reduce the mobility of contaminants as well; however, the
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 actions described for treatment under this alternative need
 to be demonstrated on a large scale.

 8.1.4  IMPLZMENTABILITY

 Availability of work force, equipment, materials, and loca-
 tions are not anticipated to be a problem for most
 alternatives.  However, locating a hazardous waste.disposal
 facility near East Helena (Alternative 4E) may be difficult.
 Alternatives could be designed not to interfere with poten-
 tial future remedial actions for other operable units.

 All fluids treatment components of the alternatives are
 implementable.  However, the in-place treatment action
 (Alternative 5S) proposes using technologies that need to be
 demonstrated on a larger scale.  Asarco is investigating the
 technical feasibility of eliminating the gain in the process
 fluids circuitry by treating 10 to 20 gallons per minute by
 evaporation processes (Alternative 5S).  Pilot-scale testing
would be required prior to full-scale implementation of the
 fluids treatment components of all alternatives.

 8.1.5  COSTS

The total present worth of alternatives ranges  from
 $6,015,300 (Alternative 5S) to $17,749,400 (Alternative 4D).
Other Alternatives (4A, 4B, 4E) have present worth costs of
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approximately $13,000,000.  Refer to Table 7-2 for specific
capital, operating, and maintenance costs.

8.1.6  LOWER LAKE ALTERNATIVES EVALUATION SUMMARY

Five alternatives (other than No Action) were evaluated for
Lower Lake.  Disposal of sediments in the smelter process
and in-place treatment of process fluids by co-precipitation
appear to be the most attractive actions.  These actions are
part of Alternative 5S.
            8.2  SPEISS GRANULATING POND AND PIT

8.2.1  PROTECTIVENESS,  SHORT- AND LONG-TERM EFFECTIVENESS,
       AND PERMANENCE

Alternatives would involve excavation of contaminated soils,
The partial or complete removal of contaminated soils, com-
bined with actions to prevent leakage of fluids, would help
prevent further groundwater contamination.  Current data
indicate that 6 feet of excavation would be required for
protecting groundwater, but excavation to approximately
20 feet is recommended.  Regardless of excavation depth,
residual arsenic and metals could potentially impact the
groundwater.
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               _...» associated with  tcavation activities are
expected   Risks to workers are typical of risks within the
smelter, and include potential exposure to arsenic- and
metals-bearing sediment and air particulates.  The long-term
reliability of both alternatives is expected to be good.

In Alternative 8B+7H, protectiveness is achieved by upgrad-
ing the existing pit and replacing the pond.  With this
alternative, there is some risk of breaking the upgraded
liner and releasing contaminants.  More protectiveness would
be offered by replacing the existing pit and pond with new
structures (Alternative 8B+7E).

8.2.2  APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
       (ARARS)

Ambient Air Quality Standards for smelting soils, the same
as for smelting ore, are expected to be met once the new
State Implementation Plan for reducing emissions takes
effect.  OSHA requirements for soils handling would be the
same as for routine smelter operation.

8.2.3  REDUCTION OF TOXICITT, MOBILITY, AND VOLUME

Mobility and volume of the contaminants in soils would be
permanently reduced.  Arsenic and metals would be treated in
the smelting process.  The mobility of metals in speiss
fluids would be reduced by leak prevention.
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8.2.4  IMPLZMENTABILITY

Equipment, personnel, and facilities required for implemen-
tation are available.  The technology for excavation and
smelting soils is demonstrated and reliable.  If necessary,
soils could be excavated to a maximum practical depth of
approximately 20 feet.

Potential conflicts with future groundwater remedial actions
may involve the impact of residual contaminants on
groundwater.  The effect of these alternatives on the
groundwater system may be monitored by a groundwater
network.

8.2.5  COSTS

The total present worth of the alternatives are $750,900
(Alternative 8B+7E) and $624,300 (Alternative 83+7H).  Refer
to Table 7-2 for specific capital, operating, and main-
tenance costs.

8.2.6  SPEISS GRANULATING POND AND PIT ALTERNATIVES
       EVALUATION SUttlART

Either alternative would be appropriate for remediation of
this area.  However, Alternative 8B+7E is preferred  because
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 it offers more protection through replacement of both the
 pond and the pit.
          8.3  ACID PLANT WATER TREATMENT FACIL]

8.3.1  PROTECTIVENESS, SHORT- AND LONG-TERM EFFECTIVENESS,
       AND PERMANENCE

Soil leach (EP toxicity) test results indicate that soils
under the acid plant water treatment facility exhibit
characteristics of EP toxicity throughout the soil profile.
For that reason, soil removal would be to approximately
20 feet to protect the groundwater.  Soils will be smelted.
Although these soils* exhibit characteristics of EP toxicity,
the metals contained within them are a by-product of the
smelting process and may therefore be returned to the origi-
nal process by which they were generated.

The risks associated with excavation are low and are similar
to those described for the speiss granulating pond and pit
alternatives.  The long-term reliability is good.  However,
residual contaminants could potentially impact the
groundwater.

Alternative 11E includes relining the settling pool  instead
of replacing it.  The use of a liner would be less pro-
tective than replacement of the pool because the liner could
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 break.  The effectiveness of the liner could be monitored by
 a  secondary leak protection system and a monitoring well
 network.  Remaining risks to groundwater would include
 potential contamination from soils underlying the relined
 ponds.  Long-term reliability depends on proper operation,
 inspection, and maintenance of the facility.  If facilities
 are properly maintained, no long-term problems should occur.

 Alternatives 11D and 11F would be more protective than
 Alternative HE.  Risks associated with acid plant fluid
 leakage to groundwater and potential leaching of contam-
 inants from underlying soils would be reduced.  The effec-
 tiveness of tank installation can be monitored by a secon-
 dary leak detection system and a monitoring well network.

 In the long-term, the settling pond and soils beneath the
 existing facility and sediment drying area could contaminate
 groundwater.  Long-term reliability is dependent on proper
 operation and maintenance of the facility.

 8.3.2  APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
       (ARARS)

Ambient Air Quality Standards, similar to those described
 for the speiss granulating pond and pit area, are expected
to be mat.  OSHA requirements for soils handling would  be
the same as for routine smelter operation.  Tank design and
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construction (Alternative 11D) are expected to meet RCRA
requirements for leak detection and secondary containment.
For Alternative HE, the lining on the pond may not meet
RCRA requirements for leak detection and secondary
containment.

8.3.3  REDUCTION OF TOXICITY, MOBILITY, AND VOLUME

For Alternatives 11D and 11F, the acid plant water treatment
facility would be replaced (except for the neutralizing
tanks), thereby reducing a source of groundwater
contamination.  The mobility of acid plant fluids would be
reduced.  Smelting would reduce both mobility and volume of
contaminants in the soils, as well as return the metals to
the process by which they were generated.  Reduction of con-
taminant mobility would be accomplished by lining the set-
tling pond and by replacing settling dumpsters and troughs.
Soils under the settling pond remain as potential sources of
groundwater contamination.

For Alternatives 11D and 11F, the mobility of fluid con-
taminants from the settling dumpsters, troughs, and sediment
drying area is reduced.  However, the main settling pond
remains a potential source of groundwater contamination.
Contaminated soils remaining beneath troughs, dumpsters, and
the sediment drying area after excavation could contaminate
the groundwater.  All alternatives (except No Action) are
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 expected to be effective in reducing the volume and mobility
 of contaminants in the soils and groundwater.

 8.3.4  IHPLZMENTABILITY

Adequate work force, equipment, and materials are available.
Excavation technology and disposal in the smelter process is
demonstrated and reliable.  Contaminated soils could be
excavated to a maximum practical depth.  No conflicts with
 future remedial actions are expected, except for potential
 impacts of remaining soils on the groundwater.  The effect
of this alternative on the groundwater system can be
monitored by a monitoring well network.  There will be no
long-term operation and maintenance for soil removal and
processing.

For Alternative 11D, tank construction was previously demon-
strated successfully at former Thornock Lake.  The tank
could be constructed within the existing pool.  This may
require temporary shutdown of the acid plant water treatment
facility.  Proper maintenance of the lined facility and the
tank would be required.

For Alternatives 11D and HE, temporary storage of acid
plant fluids during tank construction would have to be
provided.  For Alternative HE, the settling pool would
require draining, sediment removal, and possibly some
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 concrete repair work prior to installation of the liner.
 Liners are generally reliable and easy to install.

 All fluids treatment components of the alternatives are
 implementable.  In the long-term, proper operation and main-
 tenance must be performed to achieve proper handling of con-
 taminant fluids.

 8.3.5  COSTS

 The total present worth of alternatives ranges from
 $1,754,800 (Alternative HE) to $2,859,300
 (Alternative 11F).  Alternative 11D has a total present
worth of $1,958,500.  Refer to Table 7-2 for specific
 capital, operating, and maintenance costs.

 8.3.6  ACID PLANT WATER TREATMENT FACILITY ALTERNATIVES
       EVALUATION SUMMARY

 For all alternatives (except No Action) excavation to
practical limits would remove soil contaminants and help
protect the groundwater.  Smelting contaminated soils would
 reduce contaminant mobility and volume, as well as return
the metals to the process by which they were generated.
Alternative 11D includes lining the dumpster pad and  replac-
ing the concrete pad.  Alternative 11F, which  involves
replacing the facility, also would prevent leakage of  acid
plant fluids.  Alternative 11F is the preferred alternative
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                  8.4  FORMER THORNOCK  LAKE

 Only  one  alternative  (other than No Action) exists for the
 remediation of former Thornock Lake.  Variations of this
 alternative, including disposal of sediments at a hazardous
 waste  facility, could be considered.  This alternative was
 evaluated against the essential criteria.

 8.4.1  PROTECTIVENESS, SHORT- AND LONG-TERM EFFECTIVENESS,
       AND PERMANENCE

 Excavation of sediments would offer protection similar to
 that described in alternatives for Lower Lake, except that
 there  are no process fluids.  Also, community and worker
 risks would be similar.  Residual risks would include con-
 taminants already in the groundvater system.  The process of
 sediment removal and smelting is reliable in the long term.

 8.4.2  APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
       (ARARS)

Ambient Air Quality Standards for smelting sediments, the
 same as for smelting ore, are expected to be met once the
new State Implementation Plan for reducing emissions  takes
effect.  Ambient Air Quality Standards for airborne lead  in
the proposed sediment drying area are also expected to be
met.  The OSHA requirements for sediments handling would  be
the same as for routine smelter operation.
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8.4.3  RZDUCT.^i OF TOXICITY, MOBILITY,  AND VOLUME

Sediments would be removed.  Smelting similar to that
described for Lower Lake sediments would permanently reduce
contaminant mobility and volume.

The excavation, and smelting of sediments has already been
implemented for part of former Thornock Lake.  The reli-
ability of excavation and disposal has been demonstrated.
This alternative will not interfere with future remedial
actions.  However, contaminants remaining after excavation
could impact the groundwater.

Effectiveness is dependent on total removal of fine-grained
contaminated sediments.  Removal can be visually monitored
and verified by sampling.  No long-term operation and main-
tenance would be necessary if the former lake is not reused
If the pond is intended as an overflow storage facility,
then long-term maintenance of the liner system would be
required.

8.4.4  IMPLEMENTABILITY

This alternative can be implemented as a smelter operating
improvement.  Approvals from the EPA and MDHES would be
required.  An adequate work  force and materials  are
available for implementation of this alternative.
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 8.4.5  COSTS

 The present worth of Alternative 14 is estimated at $19,000.
 Refer to Table 7-2 for capital, operating, and maintenance
 costs.

 8.4.6  STATE AND COMMUNITY ACCEPTANCE

 The general reaction to the Proposed Plan and preferred
 alternatives was positive.  Refer to the Responsiveness Sum-
 mary (Appendix A) for detailed comments on the Proposed
 Plan.

 8.4.7  FORMER THORNOCX LAKE ALTERNATIVES EVALUATION SUMMARY

 Since no other alternatives (except No Action) are under
 consideration for former Thornock Lake, Alternative 14 is
 the preferred alternative.
        8.5  ALTERNATIVES EVALUATION PROCESS SUMMARY

Through the evaluation process, one alternative for each
area was identified as the most appropriate means of
remediation.  For Lower Lake, the speiss granulating pond
and pit, the acid plant water treatment facility, and former
Thornock Lake, these alternatives are 5S, 8B+7E, 11F, and
14, respectively.  The EPA and MDHES believe that these
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alternatives will satisfy most of the statutory requirements
presented in the ARARs analysis.  The choice of preferred
alternatives reflects the preference for treatment as the
principal element.
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                   9  THE SELECTED REMEDY

The remedy selected for the process ponds operable unit is a
combination of remedies, one for each of the four areas:
Lower Lake, the speiss granulating pond and pit, the acid
plant water treatment facility,  and former Thornock Lake.
This chapter presents details of the selected alternatives
for each area, including:

     •    Treatment and containment actions

     •    Costs

     •    Remediation goals and points of compliance

     •    Explanation of how the actions meet the statutory
          requirements or prescribed standards
                       9.1  LOWER LAKE

The selected remedy for Lower Lake, Alternative 5S, includes
the following actions:

     •    Replace Lower Lake with storage tanks

     •    Construct a lined pond for storm water runoff
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     •    - -place co-precipitation of  Lower Lake process
          waters

     •    Remove sediments by dredge,  dragline,  or  indus-
          trial vacuum

     •    Dry sediments on drying pad

     •    Smelt sediments in the smelter process

Since the in-place treatment of process waters has  not seen
proven on a large scale, a contingency remedy, Alterna-
tive 4A, has been selected for implementation in case imple-
mentation of the selected alternative fails to result in
achieving ARARs (or prescribed standards).  Alternative 4A
is identical to Alternative 5S, except for the way in which
process waters are treated.  Alternative 4A involves pre-
treatment of process waters followed by discharge to the
POTW.

Preparation for the implementation of the contingency
remedy, Alternative 4A, should commence immediately, so that
remedial actions will not be delayed if the selected remedy,
Alternative 5S, does not meet prescribed standards for in-
place treatment.  The EPA, state,  and local community  should
follow tha federal effluent guidelines  (40 CTR  421.72, in
part) in developing a community pretreatment  program,
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 including development of pretreatment standards, for the
 contaminants of concern.

 Actions for both alternatives are described in detail in
 Chapter 7.  The volumes of contaminants addressed by these
 alternatives are also described in Chapter 7.  The time
 required to implement Alternatives 4A or 5S will be 5 years,
 excluding smelting time.

 Smelting of Lower Lake sediments will take precedence over
 smelting sediments and soils from other areas.  However,
 during the time it takes to prepare Lower Lake sediments for
 smelting, soils and sediments from other areas should be
 smelted.  The materials requiring smelting are, in order of
 decreasing priority:  Lower Lake sediments, former Thornock
Lake sediments, soils from the acid plant area, and soils
 from the speiss granulating area.  It is expected to take 12
 to 15 years to smelt all the excavated soils and sediments.

For the selected remedy, Alternative 5S, the EPA will
 require a treatability study plan before any treatability
 study tests will be done.  As soon as possible, Asarco will
 submit to the EPA a treatability study work plan and, by
June 15, 1990, a treatability study report.  The report
should document whether or not in-place co-precipitation of
Lover Lake process waters is expected to meet the prescribed
standards presented in Chapters 7 and 10.
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            9.2  SPEISS GRANULATING POND AND PIT

The  selected remedy for the speiss granulating pond and pit,
Alternative 8B+7E, includes the following actions:

     •    Excavate soils

     •    Smelt soils in the smelter process

     •    Replace existing pond with tank and secondary con-
          tainment facility

     •    Replace existing pit with a new lined facility

Descriptions of these actions and of the volumes of material
addressed by this alternative are presented in Chapter 7.
Capital and O&M costs are shown in Table 7-2.  The time
required to implement Alternative 8B + 7E will be 2 years, not
including the smelting of excavated soils and complete
remediation of the speiss pit.  The EPA may grant an addi-
tional 12 to 18 months to completely replace the speiss
granulating pit and excavate the underlying soils.  Although
remediation of the speiss pit may be deferred to 1992,
leakage from the speiss granulating pit must be stopped
immediately by use of a liner or other comparable
technology.  Smelting of excavated soils may take up to  12
to 15 years.  Soils excavated from the speiss granulating
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 pond  and pit will be smelted after sediments and soils from
 all other areas are smelted.

 The cleanup objectives based on EP toxicity test data, will
 be excavation of soils with leachate concentrations exceed-
 ing MCLs, or excavation to maximum practical limits (approx-
 imately 20 feet).  These objectives will require additional
 soil  core sampling at the speiss granulating pond and pit.
          9.3  ACID PLANT WATER TREATMENT FACILITY

The selected remedy for the acid plant water treatment
facility, Alternative 11F, includes the following actions:

     •    Replace existing pond and settling system with
          closed circuit filtration treatment system

     •   ' Excavate contaminated soils

     •    Smelt contaminated soils in the smelter process,
          thus returning metals to the process by which they
          were generated.

Descriptions of these actions and of the volumes of material
addressed by this alternative are presented in Chapter 7.
Capital and O&M costs are shown in Table 7-2.  The time
required to implement Alternative 11F will be 1 year, not
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 including the time required for smelting excavated soils.
 Soils excavated from the acid plant water treatment facility
 will be smelted after smelting sediments excavated from
 Lower Lake and former Thornock Lake, and before smelting
 soils excavated from the speiss granulating pond and pit.

 The cleanup objectives, based on EP toxicity test data, will
 be excavation of soils with leachate concentrations exceed-
 ing MCLs, or excavation to maximum practical limits (approx-
 imately 20 feet).  These objectives will require additional
 soil core sampling of the acid plant water treatment
 facility.
                  9.4   FORMER THORNOCK LAKE

The selected remedy for former Thornock Lake, Alternative
14, includes the following actions:

     •    Excavate sediments

     •    Smelt sediments in smelter process

Descriptions of these actions and of the volumes of material
addressed by this alternative are presented in Chapter  7.
Capital and O&M costs are shown in Table 7-2.  The time
required for excavation will be 6 months.
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Although sediments from Lower Lake have high priority for
smelting, some or all of the sediments from former Thomock
Lake will be smelted first, until Lower Lake sediments have
been dried and readied for the smelter process.   Then, the
smelting of Lower Lake sediments would take precedence.
                9.5   PERFORMANCE  REQUIREMENTS

Remediation goals for all areas are the requirements that
have been identified as applicable or relevant and
appropriate requirements (ARARs)  or soil and sediment clean-
up objectives.  These goals were determined by the EPA based
on data collected during the remedial investigation (RI).

The Occupational Safety and Health Administration (OSHA)
requirements for sediments handling would be the same as for
routine smelter operation.  Ambient Air Quality Standards
for smelting sediments, the same as for smelting ore, are
expected to be met once the new State Implementation Plan
takes effect.  Ambient Air Quality Standards for airborne
lead in the proposed sediment drying area also are expected
to be met.  Tank design and construction are expected to
meet RCRA requirements for leak detection and secondary con-
tainment.
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 The  in-place treatment of process fluids will require meet-
 ing  prescribed standards identified by the EPA.C   Some of
 the  ARARs will be waived.  The prescribed standards for
 arsenic, cadmium, copper, lead, and zinc are 0.02, 0.01,
 0.004 to 0.008, 0.05, and 0.11 mg/L, respectively.  The
 point of compliance will be within Lower Lake.  In-place
 treatment by co-precipitation is expected to achieve the
 prescribed standards.

 The  depth of sediment excavation has been determined, in
 part, by the results of EP toxicity tests and the ability of
 the  leachate to meet federal drinking water standards.
 Residual contaminants in remaining sediments may  cause
 problems with meeting federal and state water quality stan-
 dards for groundwater.  For example, results of EP toxicity
 tests indicate that soils at the acid plant from  the surface
 down to coarse, groundwater-bearing gravels exhibit charac-
 teristics of EP toxicity.  Extracts from EP toxicity tests
 of these soils will not meet the federal primary  drinking
water standards regardless of depth.

 It is important to note that, although only five  elements  of
 concern were selected for the identification of treatment
 standards, there are some 18 to 20 total hazardous elements
 at elevatad concentrations in the surface water,
•Refer  to  "Statutory Determinations," Chapter 10, for speci-
fic information on waivers and prescribed  standards.
                             9-8

-------
groundwacer, soils, and sediments at the site.  The in-place
co-precipitation of surface waters is expected to lower the
concentrations of the five selected elements as well as of
the other hazardous elements.  Continued monitoring of the
process pond areas is recommended for all the elements.  If
it is determined that in-place treatment of process waters
will not meet prescribed standards, then the contingency
remedy, Alternative 4A, must be implemented Immediately.
Excavation will not be delayed.  Detailed cost estimates of
the various alternatives are presented in Table 7-2.
                     1GES  DURING
During the design and construction phase of remedial
actions, changes may be made to selected remedies.  Such
changes, in general, reflect modifications resulting from
the engineering design process.
BOI727/009.50/jms
                             9-9

-------
                10  STATUTORY DET1 ' INATIONS

Under  its legal authorities, EPA's primary responsibility at
Superfund sites is to undertake remedial actions that
achieve protection of human health and the environment.
Section 121 of CERCLA establishes several other statutory
requirements and preferences.  These specify that when com-
plete, the selected remedial action for this site must
comply with applicable or relevant and appropriate environ-
mental standards established under federal and state
environmental laws unless a statutory waiver is justified.
The selected remedy also must be cost-effective and utilize
permanent solutions and alternative treatment technologies
or resource recovery technologies to the maximum extent
practical.  Finally, the statute includes a preference for
remedies that employ treatment that permanently and
significantly reduce the volume, toxicity, or mobility of
hazardous wastes as their principal element.  The following
sections discuss how the selected remedy meets these
statutory requirements.

The selected remedy is protective of human health and  the
environment, will comply with federal and state requirements
that are legally applicable or relevant and  appropriate  or
will justify noncompliance with applicable  requirements  by
exercise of the appropriate statutory waiver, and is cost-
effective.  The selected remedy utilizes  alternative treat-
ment and resource recovery technologies to  the maximum
                             10-1

-------
 extent practicable and satisfies the statutory preference
 for  remedies that employ treatment that reduce toxicity,
 mobility, or volume as a principal element.  Because this
 remedy will result in hazardous substances remaining onsite
 above health-based levels, the 5-year review will apply to
 this action.
    10.1  PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT

The selected remedies for the various contaminant sources
including in-place treatment of Lower Lake process waters,
excavation, and smelting of soils and sediments, protects
human health and the environment through removal and treat-
ment of contaminated soils, sediments, and process fluids.
The remedies for all four areas of the process ponds will
eliminate the direct contact threat currently present and
will minimize future effects on groundwater and surface
water by removing the sources of contamination.  The
selected and contingency remedies for all four areas of the
process ponds protect human health and the environment as
described in the follow subsections.

10.1.1  LOWER LAKE

The removal of Lover Lake from the process stream will elim-
inate the primary source of groundwater contamination.  The
construction of a new lined pond ^for stormwater runoff will
                            10-2

-------
eliminate plant stormwater as a contaminant source.   The
removal of pond sediments and their subsequent smelting will
reduce the volume of contaminated soils beneath Lower Lake
and their potential for further contamination of the ground-
water beneath the lake.  The in-place treatment of Lower
Lake water by co-precipitation will be conducted in
accordance with RCRA and water quality standards.  In-place
treatment will eliminate the process waters as a source of
groundwater contamination.

The contingency for remedy for Lower Lake, Alternative 4A,
differs from the selected remedy only with respect to the
treatment of Lower Lake process waters in requiring
pretreatment and discharge to a POTW as opposed to in situ
treatment.  The contingency remedy is protective of human
health and the environment.  If the in situ component of the
selected remedy for remediation of process fluids from Lower
Lake proves to not be an effective treatment  for remediation
on a large scale, pretreatment of the process fluids prior
to discharge to a POTW will become the preferred remedy by
which to attain the level of protectiveness set by Sec-
tion 121 of CERCLA.

10.1.2  SPZISS GRANULATING POND AND PIT
                 i
The replacement of the existing speiss pond and pit will
eliminate the leakage from these facilities as a contamina-
tion source.  The excavation and smelting of  the soils
                            10-3

-------
 beneath the pond and pit will reduce the volume of con-
 taminated soils and permanently remove those soils as a
 source of groundvater contamination.

 10.1.3  ACID PLANT WATER TREATMENT FACILITY

The replacement of the existing settling system and drying
area will remove those facilities as contaminant sources.
The excavation and smelting of the contaminated soils will
reduce the volume of contaminated soils, remove them as a
source of groundwater contamination, and return the metals
to the process by which they were generated.

10.1.4  FORMER THORNOCK. LAKE

The excavation and smelting of the sediments will reduce the
volume of contaminated soils and eliminate their potential
for further contamination of the groundwater.
                                         OR RELEVJ
            AND APPROPRIATE REQUIREMENTS (ARARs)

The selected and contingency remedies will either meet or
statutorily Justify the waiver of the applicable or relevant
requirements.  The EPA selected the ARARs for remediation  at
this site and a matrix and a narrative discussion of these
are in the Feasibility Study.  In addition to the ARARs, the
                            10-4

-------
EPA and the state have agreed to consider a number of pro-
cedures that are not legally binding (EPA, 1988) .   These
requirements are To-Be-Considered (TBC) in the implementa-
tion of remedial actions.  The ARARs and TBCs are  presented
and described in Tables 10-1 and 10-2.

10.2.1  WAIVERS AND PRESCRIBED STANDARDS

Federal lav recognizes there may be instances in which ARARs
cannot be met with respect to remedial actions onsite.  It,
therefore, identifies six circumstances under which ARARs
may be waived.  However, other statutory requirements, spe-
cifically the requirement that remedies be protective of
human health and the environment, cannot be waived.  Waivers
occur as the exception, not the rule.  Waivers for
noncompliance are appropriate if:

     •    The remedial action selected is an interim remedy
          and only part of a total remedial action that will
          attain ARARs when completed.

     •    Compliance with ARARs at the site would result in
          greater risk to human health and the environment
          than alternative options.

     •    Compliance with ARARs is technically impracti-
          cable, from an engineering perspective.
                            10-5

-------
                                                                                      Tiki* 10-1
                                                                              otaciimo* UK AAAITIII or
                                                                  AmiCAiLi ot IZIIVAMT urn *rriorti»n
     •(••4ard.
    •aqtilraaMat
     Ctltarla.
                                                         Appiofr!•(•
                                                         Ill*) oc To
   Of LlAl
 ouMiCAL-mcmc

 fata Drinking
 Water Act
                                 Cltatloa
                                                            Daacilntlon
       •I frlatarf
 Drinking Wat at
 ftandatda
40 U.I.C.
JOOg I. JOOg 4.
>OOg-}

40 c.r.i. r««t  ui.
aubpait ». 141.11.
141.11. 141.17.
441.I*
                                                                                         ItA
for
                            40 c.r.i. r««t
                                                                                         TK
                                                       ^•••d •(•ndactf*  for
                                                       futile »«l«t  >7«i»«
                                                       coatMtlnant
TV> MCI* foe
Iaoi(an Ic
cooi*ttln«aca
(•l««anl «n4
•ppcapr!•(•.
                                                                                S*coBd*rf HCL*  for
                                                                                Inorganic
                                                                                centaalnaiic* «bowld
                                                                                b« (r««l*d •• 'oinar
                                                                                crticrl*. >d>la>d/an«laa plti  APWir • acid plant waiar naatMnt  facility; TL - Tboioock Uta
•OIT;i;/Ola.Ur>S)»-l

-------
                                                                              Tiki* 10 1 (CoKlcuad)
                                                                           DiscftimoM AK> MULISH or
                                                        rtcitAL AmiCAiui o* ICICVAIT MO ArrtortiATi tcquiuKzm u»i>>
•••piraawBI
Criteria..
fit Lilltllln
Ma •!•»•» Coat aal -
••at Laval Coal*


CltatlM
PM» I. Bo. »»-»t,
100 Itat. 441
IIM4I

Appcoprlala
 tko«« toll*
                           •••!•• vlklcli cr« *ub
                           )»cl to ccgulctloa
                           •• k«iai4o«« »••!••
                           »B*»t 40 C.r.l.
                           full* 141-ltt tnt
                           Fan. 114. HO, JH.
                                                                                                              §uldanc«.
                                                    •CIA foqulfMMaf • m*f
                                                    •o •»»llcabt« and/or
                                                    r«l««in( .  Mil.
                           M4I,  1)41

-------
                                                                               Tekle  10-1
                                                                            DISCI i mo* AMD  uuiYiis  or
                                                         rtoiiAL APPUCAILI on »ri-ivA«T AM>  APP»OPIIATI
                                                                                                                      lud|«.
(•!• n»»t»i
                                AIUSH

                            Lower l^ke
                            4A. »J
                                                                                                                                                              Alteroetl«e/AJU«(
Applicable for elierac-
llvee Involving dle-
ckerge to Prlcklf  Peer
Creek,  teeed on ikle
etenderd,  treeied  weiere
evet ewet  equel Ic  end
kueen heelik  elenderde.

Aleo relevem  end
epproprleie lor  dredging
ol Lower Lake,  althougk
Ik* potent 1*1  for
laf/ecte  10 Prlcklf Peer
Cieek le not  expected.
Tie** etenderde  ere
eppllcible 10 elter-
aetloee Involving dle-
ckerge to ike teet
Nelene POTU.   Slenderde
lor dleckeige efier  on-
ell* ireele»ni  lo the
POTU keve nol fei keen
developed, but  It le
enilclpeied Ike  nuabere
will be elMller  to Ike
plenl'e eliding perall.

Tkle le not en AtAI.  Ho
dleckerge I turn Ike etorvi-
weier runoff  pund le
eipecledi weiet  irollecl-
ed would be eveyoieied.
    tOIT/lr/OI».WP/Jete-l

-------
                                                                               T«bl*  10-1  (Co*)ll*M*4>
                                                                            OtSCtimO* AM)  MULTSIf Of
                                                         rtOIIAL APPLICAILI 0* ItUVAJIT AM)  At MOM I ATI  UqUIUNEHTS IAtAI.1
    Cillcrl*.
St*n4*i4>  tot
OvMr*  m*4 Opera-
tor*  ol  IUl«r4ou«
Wax* Dl*po**l
r*clllll«*
                                Cit«tlO«
                           to c.r.i. r*rt
•*c*»ll*b** •
•*tlon«l  *c*a4*rd*
vhlck 4*(lM lit*
•CC*pl*»l* ••«•§•-
•••t of b*i*r4oM*
«**t* for ovp*r» *o4
op*r*tor* of ••>•
•llt*d fcctlltl**.
                             A»r>lc*kl* (Al/
                              l*l*«*m *a4
                              A»pro*r l*t*
                             (II A I  ot To k*
                             Contldtftii
                                  A.  »IA
                                                                                                                        «nt
Tit* *li*rn*cl***
con(**>fl*i* on*lt*
•Utoaol of b*l*cdou*
Att*rm*tl«**
A44f****4 b;
    AKAi

4A. IS.
                                                                                                                                                               All*rMtl«*/AIAI*
                   Ap»llc*kl* or  i*l*>**.t
                   •nd *ppropil*i* to co«-
                   • I ruction of t«*b* for
                   •II pioc*«i poo4*. <*4I-
                   ••ai  4rrln|, *n4 an*lt*
                   I*n4flll.  S*con4*rf con
                   l*ln**ni *n4 l**k 4*t*c-
                   (loa  ffmltmt would k*
         It**<4*r4*
lor OWMI*  aid
Op*r•ton of
IUl*f4 W**l*
Tr**la*al.  ilor-
•|*.  *»4 D|*BO**|
r*ctllll«*
                           «o. c.r.i. r.t«  it}
                           1* U.I.C. t»l.  «>J.
            H**llk
l*c*kll*l»**
k*(lo«*l
(k*i 4*fla*  Ik*
•cc*»i**l* •*•*(• -
•••I of k*i*f4o
«••!• ««rl>| Ik*
•*ilo4 of lai*rlA
•(>(«• *n4 watll
cciclf lollaa of
ftit*l clo*«r*i or  If
IK* f*clllir I* •»•-
)*cl to »o*t'Clo*ui«
r*^ul i**i*ni *.  wm 1 1
                                                       •Iklllil** *i* l-l
                                                       fllUa.
                                                       k**llk
                                                                  **(*lr.
         * Hllk F*rt
14» I* can*l*t*at
•Ilk CIICLA'* go*l of
loo§-t*rv •roi*ctlo«
of k«*> k**ltk *i>4
Ik* *o*lfoB**at.  Con-
•la*i* ib* SARA pio-
vl*lo« c*|*f4liig oo
•*r*)tt vou!4 b*
i*auli*4 loi •ctlvl-
11** cooduc(*4 on-
• II*.
      40 C.f.l.              All  *U«r
100. )•, r«qul rwMnC •         nat !«••
of ih« Act apply  co         ••ctfpt Hu
• t I r«*pun*«  «ct Ivt *         Action.
( !•• und« r Ih« HCf.
                   Appllc*kl* to
                   coaiducl la* of tut*
                   for *ll pioc*** po*j4*t
                   •*4l*Mnt 4rflng *n4 011-
                   •II*  i«n4flll.  3.co»-
                   d«lf  conltlniMnl «n4
                   l«ak*(* 4*l*ctloa *f*-
                   !•••  vould b*  i*qul«-
                   •*nl«.
                                                                                                    Appllc*bl« to *ll  «ll*r-
                                                                                                    a*tl«* «cllon* «ic*pl la
                                                                                                    Aclloa *li*in*il«*«.
    •OIT/JMOI4

-------
                                                                               T.kl. 10.1 (CoatlB«*d)
                                                                            ocsciimai AM» AkALMii or
                                                         rn>t*AL »rrucAii_i ot UI.IVA*T AM> AmorauTi  uquiuxnm  IAKAI*I
llaadatd.
la*,iili*a>*Bt
Crliatla,
oi LlAltatloo. Cltat^o* D**crliilen
LocATioM-irtciric
•allomal llaioilc It U.I.C. 410 ***,nlt** fadatal
appioptlat*
(I1A) ot To t*
£pnffidllfl4 '^Kl CyavMnf
A . DM actloB cowld
.11. ct a dlxclct.
All*rB*ll»**
AIA^
Lomi Lak*
Archaeological aa4
llxotlc
       al lo*j Act
• lilotlc lit**,
»ulldla|*.  »mt
Antlqultlaa Act
                           40 C.r.l. t.IOKk)

                           it c.r.i. ran 100
It U.I.C. 4t»

40 c.r.i. t.ioiici
It U.J.C. 4»l-*tr

40 c.r.i. 4.jou«i
                            IMIO  accownc  lb«
                            •Ifacl  of  ••? f<4-
                                                      (tlci.
                                                      glkl*  lot  li>cl««lo«
                                                      !•  Ik* ••( loiul
                                                      ••(l>i«i ol Mlifoilc
                                                      flee**.
            »ioc«
ay«* 10 Bia«l4« lor
• t«>«n»lloa of •!•-
tortccl »*4 •tc»«o-
loftctl ••(• vklrh
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                                                      ol
                                                       !••«!( Ol
                                                       coA«in*cll
                                                       01  •  l«4«i
                                                       IU«i»4  >
                                                       01  >IO|I«
         to coo>ld*f
Ik* •I|*I*BC* »nd
local Ion ol land
Bjikl 01% Ib*
NaCluital ••§!•! ry of
Halulfll L«nd»«lk* to
•void uod««liablr
ijHOact* un Buih
                                                    • li«* kulldlat. «irwc-
                                                    lui«, at ob|*cl
                                                    1UI*4 OB 01 •ll«lbl«
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                                                    • Kt.  Cooc4lp«lloa
                                                    • Ilk Ik* !!•!• Hit
                                                    lode rr»»r«lloa
                                                    Olflcii I* i«quli«d.
TW ftctloo could
•ll«cl hlaioilcal
•Ifvcl • ••tyf*l Land-
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wllk III* !>l*t* Hit-
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tllllc*r !• i*^ulieJ.
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                                               •f* But *uk|*ct lo thl*
                                               Act.  Cooidln*tlon with
                                               Ik* Sl*l* Hl*lorlc*l
                                               Ofllc*  I* t*aulr*d.
Tk*r* I*  •  toMit* ch*ac*
Ikat Ikl* *ppll** lo
Lotrat L«k*.  Cuurdln*-
IIOB Milk lh* St«l*
HUlotlc  fi***tv*llun
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                   TWf* I* • t*B»t* ch*»c«
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                   L0**f Lak*.  Couidln*-
                   tloa vltk St.lt Hl.tuilc
                   ri*»*tv*lIon Olllc.l I*
                   t*9ylr.d.

-------
                                                                               T«bl«  10-1  ICoatlouod)
                                                                            PUCiimOOJ  AM AMALTSI1 Of
                                                                APPLICAILI  0*  ULIlATT  AW)
                                                                                                                     IA*AI«)
    lt»d*rd.
    CrlKrl*.
  ei I. tall it lM

•••cull** Oid«r OB
PloodpUU
Cl««« Motor Act
•octloa 404
(W*ll>nd<»  iDrodgo
i fill ••<«•».)
(u«. Ordor Mo.
llttl
4O C.t.l. Peru
2)0. (uk^aic A.
l«c(lon> 210.1.
2)0.2. 2)0.).
2)0.1. 2)0.).
2)0.4. Subfirt I.
      t C,
 ubparl 0,
 ukf*it I,
 •cllon 2)0.*l.
 ukpcit P.
        C.
 ubptit N.
)) C.r.l.. Pert*
)2I. >2(. >2*.
    ul!»• Oldll
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                                    n Co  «vo|j
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                                                                 wlib
                                                                 lodli
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4l*ck«r(* of 4t«d|«d
or fill Mtcilal
Ixo w*ll*nd< vllb-
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to »voH *4««i««
•ff«ct», •Inlali*
foloatl*! lurv. »rvj
• l«»«rv« «nd •nbanc*
llc*»l«  (A)/
                                                         !•!•*••( aod
                                                        (IIA)  oi  To  »•
                                                    Th« Lov«r I alt* !•
                                                    vllklo • 100 jot
                                                    floodplatn.
                                                                                                               AKAK
                            4A. IS
T%« pioc««« pooda m*f
b* v«il*nd«, oc w*t-
laftd* BMf i««wlt .fioa
ib« piopo<«d •ctlvlif.
A p«r>lt It MC
i«|>iti
-------
                                                      mmuu sun
                                                                                     Tabla 10- 1
                                                                                        AW> AJULTII1 Of
                                                                               o« ULIVANT AMD *rptortun
    ll*»dacd,
   l*^HlC«M*t
    CrltaMa.
                                                        Appllokl*  (A)/
                                                         l*l*««m «a4
                                                         Approfr!•(•
                                                        tltAI or To !•
   CUM All ACT
   ftoolalona
      laai Air
                                Clr«tio«
NCA-7V1  101,  111


AM la. •  ll».  ill.
• II


AaW-U.t.lOf,  tli



AOI-la.A.MOI(«)
                                                            BtltlUtiBB
I. MOVTABA MATU
   rocurrio*
   comtoi ACT
                                                       follcjt Stai«a*Bi
                                                                 kltol  «lt
                                                             a* p*rtlcul*t*
                            To yr«*«al.
                            ••4 co*Kol
                            tloa of
                            liyrov* «»t«t
                                                                                                                   Cuaaant
        lo cooatruc-
(lon tat •«4la«ni 4if-
ln| act lull !••.

        to coattnic-
Al«ar«all««a
Mdraaaad »f
.   AMK	

All cooalfuc-
tloa actl«lt•
laa talalad
to all altat-
ul l«aa.
                                                                                        I1A
                                                                                        liA
tloo >n4 ••dlMot t*
Inf •ctlvlllca.

Ap*ll*> to coaxtruc-
tloa *n4 ••dla«*l df
|B« act I»U laa.
                              -M-1-IOI
                                                                                                                                       4A.
Tka Claaa Alt Act mad
lla fioolalona aia |aa-
atallf appllcakla to I ha
plocaaa ponda.   All  ra»M •
dial action •ctldtlaa.
Including conatructIon
and aadljMnl diflag  (4A
•od i9).  axial Mat ajael-
ant atandarda fur fb
(1.1 ua,/a'> and  aactlcv-
lata Maitar.  Proeaduiaa
dutlng taawdlal  actl»l-
tlaa can pcovlda coa^tll-
anca with Ibaaa  alan-
daida.
                                                                                                                               laaad on (bl
                                                                                                                               tiaalad flue
                                                             atandard.
                                                            aa wacara
                                                                                                                                                          axial Mat ai allng
                                                                                                                                                          upaliaao wal i qualllf
                                                                                                                                                          ao no daffad I Ion
                                                                                                                                                          occuia.   Hagr alao b*
                                                                                                                                                          falavant and appropflatt
                                                                                                                                                          In fatal Ion lo aaapaga
                                                                                                                                                          of Luwai Laaa vacat  Into
                                                                                                                                                          flU-hlr  r«a( Ciaak.

-------
                                                                            Tabla  10-1  (CoajllMMd)
                                                                         Duciimo*  AM AJULTSII or
                                                  HQMTAMA iTATf ArniCAiu ot  tiuvAiT AMD ArnoriiATi uquiuxiNn  IA*AI»
 Itaarfard.
 Crllaila.
                                                     Applicable  (At*
                                                       I*lataal *»4
                                                       Affro^clac*
                                                     (ItA) at To »•
                             Citation
 t«rf«c«
                        NCA-U-V40)
                                                   Unlawful to cauaa
                                                   pollutloa of any
                                                   Itala vataca
                        14
                        I*.
                        I*
                        14.
                        14.
                        14
                           -I4.20.4O1
10.401
10.401
10.41*
10.411
10.411
10.411
                        Ci«**lfIcctloa <
                        ••!•«  qualltf
                                   by ell
                        14.10.41)
lil
 A
 A
•U
liA
 A
liA
                           •14.10.701
                                                             cl ioa
ol *cr*aM
                        policy
                                                                             Acll*lcl*( flofotmt
                                                                             could c«u»« pollution
                                                                             o( Prlcklf f«»l
                                                                             Cn.k
                                                                                                        c l*««lf lc«c ioa for
                                                                                                        filcklr r»i Ci**k.
cl«««lf leal Ion for
Laka H«l«na.
                           Co any
                   dl>cbacf« that voold
                   Incraaaa potlutlon la
                   Pilcklf Paai Ciaak.
                                                                                                                                                           AUarmall««/AIAIa
                                                                  alaodaida.  Ccaala4
                                                                  afocata valail a»al Mai
                                                                  NCLa.  Sm.1. aatf alaa-
                                                                  •aida  I at pH, DO and l*m
                                                                  paiacuca baaad oa lh«
                                                                  •!!••••• l-l claaalfl-
                                                                  calloo.  Hay alao fea
                                                                  appllcaola !• iatatlo«
                                                                  to aaapa|* of Lovai Laka
                                                                  vaiar  to Pclcfcly faar
                                                                  Ciaak.
laaad o« tbaaa
ataadaida, traatad
pcocaaa «aia» aval aaai
HCLa, SNCLa and AWQC
atandafda foe  pM,  00 and
laapaiatiiia Batad  on tka
• •I c la«*!flealIoa.  Ha/
alao ba appllcabla In
ralatloa lo aaapafa of
Umar L»k« walai Co
Pflckly faai Ciaak.

laaad oa ihla  alandaid.
tiaatad pcocaaa aual
•••i ail«ln|  upanaaa
vatai quality  ao no
da(«adat|o> oc.r.uia.  Ha,
alao ba falavant and
apptoprlata In ralatloa

vaiai Into fflrkljr Ptai
Ciaak.

-------
                                                                   Table 10-1 (CoMtMiadt
                                                                 DMCiimoa urn AJULTSII or
                                                    iT»n Apruc*iU o« MUVAMT ADO Aprtortun
                                                                                                        u*A*a>
                                                                       Applicable (»!/
Standard.
lee,elre*>ent
Criteria.
BI LlBliitln
c. rolUtto* Ole-
ctarge IlleilM-
tloa fvate*
r»r»ll
4. CrxMndweier
r»IUtlo* Con-
trol Ifete**








). ruiLIC UATBI
turniu


a. Procedural
•ulea

«. 10110 MASTC
Maucmm

lelal.lqg) Deicrlllloa, Cunildlietf H»C| Coevent
AM- U. 10. Ml Llec coadltlona and 14*
(ante lor permitting
and ackedullng

AM- U. 10. 1001, ClaaaKlcatlM, »(aa- 14*
100), 101 1 darda. aoadagrada
tloa,, aad penalKlag
lor grouodwater




14.10.101} ktoejtarM growadtvater tk* lukatantlve
pollello* coeitrol ra^ulreaaata appljr
• yataai penal!
reSulreaMnta
NCA-ri-e-IOI »eaU vlik velar * folUr ataieBent
M-t-lll ireaiaMel and oblck la generally
p«IU(lon ol pukllc •ppllcakl*
•uppllee
AM- U. tO 101 CoajtaailMM te.ela 14* OellMa MCLe end
U. 10. Ill defined, aaa^llng other drinking Mater-
Ik. 10. 111-11* protocol related paraMiere
MCA M 10 101. 111. Deal, oltk 14*
11* conta*ln«ied aolla
HCA-f)- 10-111 that are not


Alternative!
Addreaaed kf AlterMt Ive/ARAAe

** Appllea only to
alternative that
dlackargca tkrougk the
ruTU to Prtcklr Fear
**. 11 laaed .. .h...
etandarda, treated
vaiera auat aeet
grounduater NCLa and eot

m»k» |roundvtt«r
h-tratul, daCrlMnlal. or
heellh.
4A, )S. Tiile AlAft apeclrlea aub*
••>>!, atanllve requlreaenle ol
IIP. 14 the pervlt eppllcatlon
that ault be m*l .
»*. 19.
tt'ii. nr.
M

**. 19.
•I>;E. ur.
'*

14 •!• ff*I«v«nc 10
• If •mat lv«« **h«r« colld
»oiTn;/oi» up/j..

-------
                        MMT/UU tun
                                                                                Tekle  10-1  (CoeitlMied)
                                                                             ouciirrio* tao AJULYSII or
                                                                                   uu«*rr AJK> *rrtonun
    Criteria.
  • i Ltaltatloei

•. lefuee  Olapoeal
». NOHTAaU  •AXAAD-
   OUS WASTl ACT
  Citation
l-U-U-m. MM.
>.  »IO. III. JJJ
                                                              *••!• Htfo
                                                        • lit l*|«l>tlo»
-M-IO-40I. «M.
       ale I*)/
 lalavaal and

III*) or To »e
ConaUttid IIICI

     II*
                                                          II*
                                                                                                              A1AI
                                                                              Ittlnj •(•ntfitd
                                                                                    for tolld H*
                                                                                  ««(«4 lion pco
                                                                                   pond*
                                                     »«. 11.
                                                     ii./t. ur.
                           40*
                                                                                                                                         *••/(
                               •!».««.IOt-110
                                                                                         It*
   llOB*
                                                                                                            CItCL* do««  >ol
                                                                                                            c«quli« f«rBll<  foi
                                                                                                                                 *!!•»•( I»/*IAI*
ttaadndt fuldlng tk«
han4lla| of  tolld «••«.
                                                                                                                             la coo«l ruction of
                                                                                                                             for all proc*«»
                                                                                                                             ••dla«ai drflng.  ao4
                                                                                                                             o«>lt« lindltll.  rb
                                                                                                                             l*qy|r«Mnl> Include
                                                                                                                             •••ur«nc«« for
                                                                                                                             prottcclon.  «o4 preclude
                                                                                                                             con«C ruction of •
                                                                                                                             facllllf oil bout f«Tl«v«
                                                                                                                             •ad approval* for the
                                                                                                                             facllltf.  Huvavar.  If
                                                                                                                             tbe facility la
                                                                                                                             cooatructad onalte.  •
                                                                                                                             parvlt !• not required
                                                                                                                             under CtlCU.

                                                                                                                             •elavanl aod appropriate
                                                                                                                             to cooal ruction of tanaa
                                                                                                                             for ell procaia ponda.
                                                                                                                             ••dlMol dlrlng. and on-
                                                                                                                             alte landfill.   rh«l«
                                                                                                                             raqul raartnt • aalabllab
                                                                                                                             eionllorlng,  racord
                                                                                                                             keeping, and reporting

                                                                                                                             raqulreewnta.  * perailt
                                                                                                                             le not required II f ac -
                                                                                                                             Illtlea are  «:on«t rucled
                                                                                                                             oa«lte.
   gOIT;j//OI*.Wf/)a«-IO

-------
                                                                                Takla 10-1 (Coatlniad)
                                                                             ouctimoa AK> AJULTIII or
                                                      NOMTAJU STATE AFfLllUlU  O« ULIVAJIT UK AfriOMIUTl UgUIUHHTS  (ARALI
    Criteria.
  or Limitation
                                                                                            U (A)/
                                                                                     •• !•«••!  ftttj
                                                                                     A^f co^clci*
                                                                                    (I1A)  ot To M
                                Citatloa
                                                            D«acflallon
                              -U.t4.llO.
                                                       Cratant* of f«rt  1
                                                                                                                                             AJLAK
                                                                                            by
                                                                                         IV*
                                                                                                                                                                     lit
                                                                                                                                                            t«U»nI t*4 tfftofiltt*
                                                                                                                                                            to condcuctlon of !••»•
                                                                                                                                                            for all pioc««« pond»v
                                                                                                                                                            ••4lMal diylng,  and  OB-
                                                                                                                                                            • II* l.oddll.
                                                                                                                                                            ••^uliMMnl* In lkl>
                                                                                                                                                            •I«>d
                                                     •CftA
                                                     b.
                                                                    II
                                                                                  •!•/•.
                                                                                                            If toilc.
                                                                                                                                          A. JJ
k.
                                        I,  »OJ.
                                4U
   C«IMI«IOI*  Of
H**ir«*l. packaging,
••4 4oc«M**l«llon
        ••(•  for
                                                                                                                   If h«i
                                                                                                                        la*al  of
                                                                                                                    pond
Apfllokl* to
r*Buv«l !• L4M««r l^k«
• nd fount l«ll|r
•ppllcakl* lor  hodllng
of ••dlMOti •••ucl.txl
wltb th« •p«l«t pund and
pit »d lk« acid plant
•aiar naana.nl lacllltf
and lonwr Thoinock
Uk*.

Allaiudxa Includa
coBblaalluna of ona ol
ika abova alt arnal Ivaa.

•ppllaa to any  ganara-
tlon of haiaidoua waal*.
    •OIT>2}/OI».wr/)*u-ll

-------
                                                                               T»bU 10-1 (CoxlviMd)
                                                                            DlJCIirriOB AM AJULT3I1 Of
                                                     WTTAJU ITATI  AmiCAiLi  o*  uuvAjrr MO Arrtortun uquiUMmn  
    Crlt*rl«,
c. tt*m4mi4t  for

              W*«l«
                                Cluttoa
                                                           P««Cli»tlQ«
                              -U.4«.»0*
                                                                                Appropriate
                                                                                III*)  or  To M
                                                                                Conitdmd  ITKl

                                                                                    *. IU
Alttrut !•••
A44i«»««d by
                                                                                                                                   *A.
                                                                                                                                                             All*ra»i Ix/AIAI*
                                                                                                                                                      Appllcikl*  or  i«U»*l
                                                                                                                                                      •ad *pproprl«i« to coa-
                                                                                                                                                      • I met Ion ol !••»• for
                                                                                                                                                      •II pr»c««» foot*. •«4|
                                                                                                                                                      Itndflll.
                                                                                                                                                      KlraMol »
                                                                                                                                                      tloo  fjn
                                                                                                                                                                          4«t*c-
4. runon.ii  «•>
                           HC*-r«-)-ISI t 101
                           J4-V40I. 40*. 404
                                «.IJ.II*
                                                           MMac pracclo
                                                                                                       •••K on if *ppir if
                                                                                                       •CI|»1(I» •!• 00-
                                                                                                       • II*
                                                                                        liA
                                                                                                                                      4*. »»
                                                                                                                                      4A. II
••forcwMM
                                                                                                             i.1,. «•• ol
                  for •lt«rnac tv«« l»olv-
                  l«f ••4la*nt rrao*«l  of
                  l^nxi Uk«. wklck U  !•
                  lb« I00-f»r
                                                                                                                                                         for •kt«rn*tlv««  lavolv-
                                                                                                                                                         log ••4lB«nt  i««o««l of
                                                                                                                                                         L0w«r L«k«, wblck I* In
                                                                                                                                                         Ch« I00-)r«*i
                                                                                        liA
                                                                                                                                      4A. IS
                                                      Ilao4 •(•••llaot not
                                                                                                                                                      l*l*»at tat •pproorl*!*
                                                                                                                                                      for »U«rn«t !»•• ln*ol»-
                                                                                                                                                      lag ••dlB«nt i*mntl of
                                                                                                                                                      Lo««r Lab*. »Mck !• In
                                                                                                                                                      tb« IOO r««i flao4>l«ln.
                                                                                                                                                      auMixr, p«i>lltlnf
                                                                                                                                                      would not b« • ••qult«-
                                                                                                                                                      •Miil und«i CIICLA.

-------
                                                                               T*klo  10-1  (Co«lt.Md)
                                                                            DUCimiCM)  MO UULMI1 Of
                                                      NOVTABA ITATt ArniCAILI O* ULEVAMT MO AmoniATI ItqUIUMBT? 
    •toadlld.
   •••ptroMBt
    Criteria.
7. AITiqUITIU
                             I-II.(.101
                                                              •»!• lor
                                                       Idonllf lent Ion. •*•!-
                                                       llo« of
                                                                  t ologlcal
                                        <*>/
                                       mm4
                                       l*
                             (It*)  ot  To »•
                                 Utii

                                 •I*
                             Att*nutl««*
                             *4«r««>*4 bf
                                 AtAI

                             All Lo-.r
                             Uk«
                             •lltroat!«••
                                                                                                                                                               All*CMtl««/AIAI«
                                                                                                    A mot* ck«K« tkcl
                                                                                                    tkl* AIAI tfflltt to
                                                                                                    Loo*i L«k«.  Tk» fond
                                                                                                    lt«*ll !• !••• ik«n
                                                                                                    JO ;••'• old. kui Mf
                                                                                                    k «• k««n «*td •!•-
                                                                                                    « otialf.   C«iMf«llft
                                                                                                    • tlltcii or •iiuctnit*
                                                                                                    I •• Ik** 10 i««r* old
                                                                                                    • • not  «uk|«ct to tkl*
                                                                                                    or (Uillai Act*.   Cootdl-
                                                                                                    Ml loo vltk lk« tin*
                                                                                                    • Utorlol UKIc* U
• . OCdtMTIOMJ.
   •ALTM
• . fcUo ••d Air
                           NCA-M) 70  101
                              •It.41.101,  101
Fret (Clio* of
k*«ltk »m
Ik* M9ik fl«c

•alt* Md «tt
CO«««BlU>t  l
tm lt» woik  f
                                                                         tm
Mock»r ««r«ir will
•••4 to t« m44l»*m»t
lot mil •lt*rn«llv«*.

Wock«i ttltlj will
»««d lo k« •d4i«**«4
lot all •ll«in«t!••«.
All alter-         Appllctkl*  to  •!! altir-
ull<*»            Htl«* ict Ion* nctpt Ho
•ic<»t Bo          Action •lt«in«tl«»».
Action             Till* >t«nd*id  >p«clll**
                   woik*r h<«ltk  
-------
      •    The remedial actions selected will attain an
          equivalent standard of performance, although ARARs
          are not met.

      •    With respect to state ARARs, the state has incon-
          sistently applied ARARs in similar circumstances
          at other remedial actions within the state.

      •    In the case of fund-financed remedial actions,
          financial restrictions within the Superfund
          program require fund-balancing such that satis-
          faction of ARARs at the site must give way to a
          greater need for protection of public health and
          welfare and the environment at other sites.

The feasibility study, which provides a detailed analysis of
the remedial action alternatives, identifies how each alter-
native complies with ARARs.  The ARARs that will not be met,
those for in-place treatment of Lower Lake process waters,
will  require waivers.

The EPA and state have identified state water quality stan-
dards for water and fish ingestion  (arsenic only) and for
long-term protection of aquatic life  (remaining elements) as
the applicable numerical limits for remediation.  These
numerical limits are:

          Arsenic        2.2 nanograms per liter
          Cadmium        0.0011 milligram per liter
                            10-19

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          Copper       .  0.012 milligram per liter
          Lead           0.0032 milligram per liter
          Zinc           0.11 milligram per liter

Neither the preferred remedy component of in situ treatment
nor known standard treatment methods (water treatment facil-
ity) will attain the applicable numerical limit for arsenic,
cadmium, or lead.  These applicable numerical limits (ARARs)
cannot be met because of technical impracticability, as
elaborated below.  Instead, attainable standards hereinafter
referred to as prescribed standards have been established.
The applicable numerical limits for copper and zinc are
attainable by either the preferred or contingency remedy.

10.2.1.1  Arsenic

The prescribed standard for arsenic in Lover Lake process
waters after in-place treatment is 0.02 mg/L.  The state
water quality standard for arsenic, 2.2 nanograms per liter
(0.0000022 mg/L) will be waived on the basis of technical
impracticability.  It is technically impracticable to attain
such a level by existing water treatment methods and it  is
impractical to measure arsenic at this concentration.  The
reason for selecting 0.02 mg/L as the prescribed standard  is
that this concentration is in the upper range of water
quality data measured for Prickly Pear Creek, as measured  in
Phase I and II remedial investigations.  This concentration
of arsenic,  0.02 mg/L is an achievable standard and  is below
the federal primary MCL of 0.05 mg/L.
                            10-20

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 10.2.1.2  Cadmium

 The prescribed standard for cadmium in Lower Lake process
waters after in-place treatment is 0.01 mg/L  The state
water quality standard for cadmium, 0.0011 mg/L, which is
based on long-term protection of aquatic life, will be
waived on the basis of technical impracticability.  It is
 impractical to treat process waters for removal of cadmium
to this concentration.  The next promulgated standard above
the state water quality standard is the federal primary MCL.
The prescribed standard for in-place treatment of cadmium in
Lower Lake waters, the primary MCL, 0.01 mg/L, is
technically achievable.

 10.2.1.3  Lead

The prescribed standard for lead in Lower Lake process
waters after in-place treatment is 0.05 mg/L.  The state's
ambient water quality standard for lead, which offers  long-
term protection of aquatic life, 0.0032 mg/L  (at  a water
hardness of 100 mg/L CaC03),  will be waived on the basis of
technical impracticability.  The existing water  quality of
Prickly P«mr Creek is slightly above the state water quality
standard of 0.0032 mg/L lead.  Lead concentrations in
Prickly Pear Creek above the smelter range  from  0.005  to
0.007 mg/L.  Ideally, the treatment objective for lead
should be within this range.  However, treatment of water  to
                            10-21

-------
within  this range of lead concentrations, 0.005 to
0.007 mg/L, is not technically practicable.  The prescribed
standard of 0.05 mg/L lead, which is the next promulgated
standard above the state water quality standard, is
achievable by current water treatment methods.

10.2.1.4  Copper and Zinc

The prescribed standard for copper in Lower Lake process
waters  after in-place treatment is 0.004 to 0.008 mg/L.  The
most stringent promulgated standard identified for copper
(0.012 mg/L) is based on long-term protection of aquatic
life.  However, copper levels in Prickly Pear Creek, both
above and below the smelter, are in the range of 0.004 to
0.008 mg/L.  Because current treatment methods can be
expected to reduce elevated copper in Lower Lake to within
this range, the prescribed standard is selected on the basis
of nondegradation.

The prescribed standard for zinc in Lower Lake process
waters after in-place treatment is 0.11 mg/L.  This state
water quality standard is based on long-term protection of
aquatic life and it is the most stringent promulgated  stan-
dard identified for zinc.  Current treatment methods can be
expected to reduce elevated zinc in Lower Lake to this
standard.  The existing water quality of Prickly Pear  Creek,
above the smelter, occasionally exceeds 0.11 mg/L zinc.
                            10-22

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                  10.3  COST-EFFECTIVENESS

The selected remedial alternatives are cost-effective
options for cleanup of the process ponds operable unit.
This determination is based on the cost and overall effec-
tiveness of the selected remedies when viewed in light of
the cost and overall effectiveness of other alternatives.  A
discussion of the cost-effectiveness for selected alterna-
tives for each area follows.

10.3.1  LOWER LAKE

The selected alternative for remediation of Lover Lake,
Alternative 5S, includes in-place treatment of Lower Lake
process water.  This alternative is attractive because of
the relatively low cost, approximately $6 million (present
worth).  However, in-place treatment of process waters is an
unproven technology on as- large a scale as would occur
herein and may not meet remediation goals.  Sediments would
be excavated and disposed in the smelter process.  The con-
tingency remedy for Lover Lake is Alternative 4A which
includes replacement of Lover Lake, excavation and smelting
of sediments, pretreatment of process fluids, and further
treatment of process fluids in the East Helena POTW.

The principal difference between alternatives is the
proposed means of sediment disposal:  smelting the
                            10-23

-------
 sediments, disposal in an offsite hazardous waste disposal
 facility, and disposal in a proposed new hazardous waste
 disposal facility in the East Helena, area.  Both the
 selected and contingency remedies include treatment and
 disposal of sediments in the smelter process.  This process
 allows recovery of trace metals and reduction of contaminant
mobility and volume.  The disposal of sediments in a
proposed RCRA landfill to be constructed in the East Helena
 area was of comparable cost, approximately $12 million, but
does not include treatment as a principal element and does
not reduce the volume of contaminants.  The disposal in an
offsite hazardous waste disposal facility was determined to
be approximately $5 million more expensive than disposal in
a new hazardous waste disposal facility in the East Helena
area.

Other variations on alternatives for Lower Lake include the
means of disposal of Lower Lake fluids.  Pretreatment of
fluids followed by treatment at the East Helena Sewage
Treatment works may be less cost-effective than in-place co-
precipitation, but more cost-effective than disposal to
Prickly Pear Creek.  Disposal to the POTW would cost
approximately $1 million less than disposal of process
fluids to Prickly Pear Creek.  The extra costs involved with
disposal to Prickly Pear Creek arise from the more  stringent
pretreatment requirements to be met prior to stream
discharge.
                            10-24

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 10.3.2  SPEISS GRANULATING POND AND PIT

 The  selected alternative for the speiss granulating pond and
 pit, Alternative 8B+7E, includes replacing the speiss granu-
 lating pond and pit, and excavation and smelting of soils.
 Replacement of the pond and pit would offer more protective-
 ness than Alternative 8B+7H, which would replace the pond
 and  repair the pit.  The difference in cost is approximately
 $130,000.

 10.3.3  ACID PLANT WATER TREATMENT FACILITY

 The  preferred alternative for the acid plant water treatment
 facility, Alternative 11F, includes replacing the settling
 dumpsters and pond with a closed-circuit filtration system,
 and  excavating and smelting soils.  This alternative offers
more protection than Alternative HE, which involves repair
 of the pond (instead of replacement).  Alternative 11F  is
 approximately $1 million more expensive than Alterna-
 tive HE.  Alternative HF would also be more protective
 than Alternative 11D, which involves replacement of the
 settling dumpsters with new settling dumpsters and replace-
ment of the pond with a steel tank.  Alternative HD would
cost less than Alternative 11F  (approximately $2 million
versus approximately $2.9 million).   Alternative  11F,  the
selected remedial action, includes a closed-circuit filtra-
tion system and, although it costs more, it offers more
                            10-25

-------
 protection for the underlying groundwate.r than the other
 alternatives.

 10.3.4  FORMER THORNOCK LAKE

Since only one alternative was considered for remediation of
former Thornock Lake, a cost-effectiveness evaluation was
unnecessary.  However, several means of sediment disposal
were considered for this alternative.  As discussed for the
Lover Lake alternatives, smelting the sediments was deter-
mined to be the most protective and cost-effective means of
disposing of the sediments.
  10.4  UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE
  TREATMENT TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE

The selected remedies satisfy the statutory preference for
utilization of permanent solutions and alternative treatment
technologies.  Treatment is a principal element of the
alternatives selected for all areas.  They are permanent
solutions in that they will decrease the concentrations of
contamination sources.  Selected alternatives for all areas
include treatment or recycling of soils and sediments in the
smelter process.  The process waters of Lower Lake will also
be treated.  The selected alternative includes in-place
treatment of process waters by co-precipitation.  The
                            10-26

-------
contingency alternative includes pretreatment of process
waters, followed by treatment in the East Helena POTW.
BOIT727/010.50/jms
                           10-27

-------
               11   DOCUMENTATION OF SIGNIFICANT CHANGES
11.1  PREFERRED ALTERNATIVES AS PRESENTED  IN THE PROPOSED PLAN

 The Proposed  Plan  for  the East Helena  smelter  site was
 released  for  public  comment in August  1989.  The  Proposed .
 Plan identified preferred alternatives  for each area.  The
 preferred alternative  for Lower Lake, Alternative 4A, was to
 replace Lower Lake,  excavate and smelt  sediments, pretreat
 process fluids,  and  treat fluids in the East Helena  sewage
 treatment facility.  The preferred alternative for the
 speiss granulating pond and pit, Alternative 8B+7E,  was to
 replace the speiss granulating pond and pit, and  excavate
 and smelt soils.   The  preferred alternative for the  acid
 plant water treatment  facility, Alternative 11F,  was to
 replace the settling dumpsters and pond with a closed-
 circuit filtration system, and excavate and smelt soils.
 The preferred alternative (Alternative  14) for former
 Thomock  Lake was  to excavate and smelt the sediments.  The
 EPA reviewed  all written and verbal comments submitted
 during the public  comment period.  Upon review of these  com-
 ments, it was determined that significant changes to the
 remedy, as it was  originally identified in the Proposed
 Plan* were necessary.
                             11-1

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        11-2	CHANGE IN SELECTED REMEDY FOR LOWER LAKE

The EPA has determined, based on information received during
the comment period, that the preferred alternative for Lower
Lake, Alternative 4A, no longer provides the most
appropriate balance of tradeoffs among the alternatives with
respect to the evaluation criteria.  Information available
to the EPA has suggested that another alternative from the
Proposed Plan and RI/FS report, Alternative 5S, provides the
best balance of tradeoffs.  As indicated in the Responsive-
ness Summary, the EPA has acknowledged, in both the Proposed
Plan and the public meeting, that Alternative 5S should be
re-evaluated if new and relevant information became avail-
able.  In light of Asarco's September 20, 1989, proposal for
pilot-scale tests, in light of requests by concerned resi-
dents and local government officials, and in light of
independent assessments by the U.S. Bureau of Mines and the
Montana College of Mineral Science and Technology, the EPA
has determined that the in situ treatment method using
ferric chloride is the preferred method to be applied in
this remedy.  The public was apprised previously that Alter-
native 5S might be selected as the remedy; thus, the public
had adequate opportunity to review and comment on it.

If pilot-scale tests of in situ co-precipitation methods
prove this innovative technology to be ineffective in terms
of treating Lower Lake waters to prescribed standards, the
EPA will require construction of a water treatment facility.
                            11-2

-------
 Such a facility will be designed to remove metals and
 arsenic to yet-to-be-determined levels for discharge to the
 East Helena publicly-owned wastewater treatment plant.
          11.3  CHANGE IN IMPLEMENTATION TIMES FOR
                    SELECTED ALTERNATIVES

The EPA has made a change to a component of the selected
alternatives that has resulted in an alteration to the scope
of the remedy.  The overall waste management approach repre-
sented by the alternatives has not been affected.  In the
Proposed Plan, the implementation times for Alternatives 5S,
8B+7E, 11F, and  14 were 4, 2, 1, and 0.5 years,
respectively.  However, these time estimates did not account
for:

     •    The recommended depths of excavation

     •    The additive effects of smelting times

The depths of excavation recommended by the EPA in the Pro-
posed Plan were greater than those which Asarco used to  cal-
culate implementation times.  Also, the implementation times
presented in the FS and the Proposed Plan did not account
for the slow rate of smelting excavated sediments and soils.
The smelting of all excavated soils and sediments may take
longer than anticipated.  The estimated implementation times
                            11-3

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 for alternatives in this ROD are presented in the following
 subsections.

 11.3.1  LOWER LAKE

 In the FS, the time for remediation of Lower Lake under
Alternative 5S is A years, assuming an average excavation
 depth of 3 feet.  The EPA has decided, based on EP toxicity
 data and other data from the RI, that excavation to an aver-
 age of 4 feet would provide greater protection to the
 groundwater.  The EPA has determined that 5 years should
 provide ample time for remediation of Lower Lake,
 considering the increase in excavation depth.  Smelting of
 Lover Lake sediments will take precedence over smelting
 sediments and soils from other areas.  However, during the
 time it takes to prepare Lower Lake sediments for smelting,
 soils and sediments from other areas should be smelted.  The
materials requiring smelting are, in order of decreasing
priority:  Lover Lake sediments, former Thornock Lake sedi-
ments, soils from the acid plant area, and soils from the
 speiss granulating area.

 11.3.2  SPEISS GRANULATING POND AND PIT

In the FS, the time required for remediation of  the speiss
granulating area under Alternative 8B+7E  is 2 years,
assuming an excavation depth of 6 feet.   The EPA has
decided, based on EP toxicity data, that  excavation will be
                            11-4

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 as  deep as 20 feet, or to the practical limit of excavation,
 to  provide greater protection to the groundwater.  The EPA
 has determined that remediation of the speiss granulating
 pond, except for smelting the excavated soils, should take
 2 years.  Remediation of the speiss pit may require an addi-
 tional 12 to 18 months.  Smelting of excavated soils may
 take 12 to 15 years, considering that soils from this area
 have low priority for smelting.

 11.3.3  ACID PLANT WATER TREATMENT FACILITY

 In  the FS, the time required for remediation of the acid
 plant water treatment facility under Alternative 11F is
 1 year, assuming an excavation depth of 5 feet.  The EPA has
 decided, based on EP toxicity data, that excavation will be
 as  deep as 20 feet, or to the practical limit of excavation,
 to  provide greater protection to the groundwater.  The
 implementation time for remediation excluding the time for
 smelting soils should be 2 years.  Soils will be smelted
 after all excavated sediments from Lower Lake and former
 Thornock Lake have been smelted.

 11.3.4  FORMER THORNOCK LAKE

 In  the FS, the time required for remediation of  former
Thornock Lake under Alternative 14 is 6 months,  assuming
excavation to 5 feet below the surface.  Based on RI data,
the EPA has decided that excavation will be 2 feet below  the
                            11-5

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layer of artificially-deposited sediments to provide greater
protection to the groundwater.  The data from the RI indi-
cate that the average depth of the artificially deposited
layer is 3 feet.  Therefore, the EPA concurs with the
estimated implementation time of 6 months, excluding the
time for smelting sediments.  The excavated sediments can be
smelted during the initial stages of implementing remedia-
tion of Lover Lake, until Lower Lake sediments are ready to
smelt.  Then, the smelting of Lower Lake sediments would
take precedence, with Thornock Lake sediments second in
priority.
BOIT727/011.50/jms
                            11-6

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                        12 REFERENCES
Bureau of Land Management (BLM).   1983.  Headwaters Resource
Area, Resource Management Plan/Environmental Impact State-
ment.  May 1983.

Hydrometrics.  1988b.  Assessment of a Class II Landfill
Site Near Montana City, Montana.   Prepared for City/County
Sanitation Service, Helena,  Montana.

Patterson, J.  U.S. EPA, Office of Research and Development.
Cincinnati, Ohio.  Personal Communication.

Thomas, L. M. 1988.  Recommended Agency Policy on the
Carcinogenicity Risk Associated with the Ingestion of
Inorganic Arsenic.  Memorandum to EPA Assistant
Administrators, from Lee Thomas,  EPA Administrator.
Washington, D.C.

U.S. EPA.  1986c.  Superfund Public Health Evaluations
Manual, EPA 540/1-86/060, Office of Emergency and Remedial
Response.  Washington, D.C.

U.S. EPA.  1987.  Remedial Investigation of Soils, Vegeta-
tion, and Livestock for the East Helena Site (Asarco), East
Helena, Montana.

U.S. EPA.  1988.  CERCLA Compliance With Other Laws Manual.
COSWER Directive 9234.1-01.   August 1988.

U.S. EPA.  1989a.  Second quarter FT89 health effects
assessment summary tables.  Environmental Criteria and
Assessment Office, OERR 9200 6-303-(89-2) .  Cincinnati,
Ohio.

U.S. EPA.  1989e.  Integrated Risk Information System,
April, 1989.  Office of Research and Development.
Cincinnati, Ohio.
BOIT727/013.50/jms
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                            RESPONSIVENESS SUMMARY

                       PROCESS PONDS OPESABLZ UNIT OF THE
                       EAST  HELENA SMELTER. SUPERFUND SITE

                             EAST HELENA. MONTANA
                                 October 1989
      The U.S. Environaencal Protection Agency (E?A) held a 21-day public
cor-aent period from August:  31 to September 20, 1989. co provide an opportunitv
for interested parties to cocaent on EPA's Proposed Plan for the Process Par.ds
Operable Unit of the East Helena Saelter Superfund site.  Consents vere also
sought concerning the Feasibility Study Report (FS Report) recently completed
by Asarco Incorporated.(Asarco) .

      A responsiveness sucaary is required by the Superfund law to provide EPA
and the public with a suacary of concerns about the site, and EPA's responses
to those concerns.  EPA oust consider such public input before making a final
decision on a cleanup remedy, which is then documented  in the Record of
Decision (ROD).     •

      This responsiveness summary contains three main sections:

      I.    Overview.  This section briefly describes the proposed remedial
            alternatives evaluated in the FS and presents EPA's preferred
            remedial alternative for each component of  the Process Ponds
            Operable Unic.

      II.    Background on Community Involvement. . This  section  provides a
            brief history of community involvement at the site.

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      Ill.   Summary  of  Questions and Comments deceived Durir.g th«> Public
             Comaent  Per;od  ar.d EPA's Responses to Those Cor.-.er.rs.   Th i s
             seccion  presents  comments submitted to EPA during the public
             comment  period  and provides EPA's responses to chose corarr.er.ts
I. •    OVERVIEW

      The Ease Helena  scelter  is an active lead-smeltir.g  facility operated by
Asarcp in East Helena,  Montana.  The plant covers approximately SO acres.  The
shelter began operations  in  1888 and processes ores and concentrates frorr.
around the world.   The  plane produces lead bullion for shipment to another
Asarco facility, where  it  is further refined.  Froa 1927  to  1982 the plar.t
also recovered zir.c from  the saelter's waste slag.  American Che^.et
Corporation  operates a  paint pigment plant next to the smelter.

      The site was  added  to  EPA's National Priorities List of hazardous waste
sites in 1983.  To  better  manage the site studies and cleanup wor.<, EPA
divided the  site into  five operable units:  process ponds and fluids (the
subject of this responsiveness  summary); ground water; surface water and
soils; the slag pile;  and  the  ore storage areas.  Studies indicate that  the
process ponds are a major  source of the  metals  (especially  lead and cadniu,T.)
and arsenic  found in site  soils, ground  water,  and surface water.  EPA has
determined that remediation  of the process pond contamination  is  the highest
priority for the East  Helena site.  The  remaining operable  units  are being
studied in a Comprehensive Site-Vide Remedial  Investigation/Feasibility  Study
(RI/FSJ.       .

      The process ponds have been divided  into  four  components:   Lower  La'ice,
the speiss granulating pit and pond,  the acid  plant  water treatment  facility,
and Thornock Lake.   Lower Lake collects  and  stores  water used in  the  main
plant process circuit  *s  well  as stora  water  run-o.ff.   The  speiss granulating
pond and pit score  vacer  thac  is used  to cool  che  hoc speiss as pare  of che
granulation  process, and  che acid plane  wacer  creacmenc facility  rtmoves

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particulates  from scrubber fluid.  Thomock  Lake  was used to  settle  suspended
solids from the main process water circuit until  October  1986,  vher.  it vas
replaced by a tank.

      The Proposed Plan of August 1939  announced  EPA's  preferred  alternative
for each of Che process pond subunits.   These  alternatives are  described
below.
      Lover Lake ^Alternative ^aV   Two  large  steel  tanks  would replace  L=ver
      Lake as the plant's primary water  holding  facility,  and a lined pcr.d  i-
      additional tanks would be constructed  for  emergency  containment of storm
      runoff.  Sediments would be excavated  to remove  the  artificially
      deposited sediment and sludge layer  (approximately 1-3 feet)  at the
      bottom of Lower Lake.  EPA has classified  such bottom deposits  in
      surface impoundments at lead smelters  as hazardous wastes.   EPA requires
      that these sediments and sludges be  removed  and  treated or disposed of
      safely.  The preferred treatment in  this alternative is to dry  them on
      lined drying pads and then smelt them.   Smelting these wastes would
      enable Asarco to recover small amounts of  lead and other metals
      contained in the sediments.  More  importantly, it would imaobilize the
      remaining arsenic and metals within  the  slag produced in the process.

      Many modifications to Alternative  4a were  examined.   Based on
      information obtained from soil leach tests,  fresh water percolating
      through sediments at the bottom of the artificially  deposited layer
      would still meet federal primary drinking  water  standards. "However,  a
      key modification to this alternative would require excavation of an
      additional two feet below the artificially deposited sediment and sludge
      layer.  This modification provides a margin of safety and it offers
      greater assurance chat Lower Lake  water, once treated, will  still meet
      federal drinking water standards after coming into contact with the
      remaining sediments.

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 Once  the  sediaencs are excavated and placed on drying pads for eventual
 smelting,  the water  in Lower  lake would be treated to meet specified
 standards  before being discharged into the East Helena Publiclv C-T.ed
 Treatment  Works  (?OTV).

 Speiss' Grar.ulatir.z ?it and  Pond (Alternative 9b*"e1.  A steel tank with
 a  liner,  leak detection system, and secondary containaent and recovery
 capability would replace  the  existing speiss granulating pond.  The
 speiss granulating pit would  also be replaced by a new leakprsof
 concrete pit with a  liner,  leak detection systea, and secondary
 containsenc and recovery  capability.  Pit replacement say require
 Interruption of plant operations for about 30 days.

 During construction  of these  replacement structures, soils underneath
 and adjacent to the  existing  pond and pit would be excavated and set
 aside for  smelting.  Prior  to sneiting. the saae precautions against
 fugitive air emissions that are afforded the ore piles would apply to
 the soils..
The required depth of soil excavation, based upon results of soil leach
tests, would be approximately six  feet.  However, a key modificatior. of
this alternative considers other factors that suggest  the advantage of
deeper excavation.  New structures will be built once  excavation
cavities are refilled.  If for any reason it is determined  later that
more excavation of contaminated soils  should have been performed, the
new structures would have to be aoved  or disassembled.  Further, because
the voluae of soils involved in excavating beyond six  feet•-perhaps down
to 20 feet--is relatively small at the speiss granulating pond  and pit
(a few hundred square feet of ground,  as opposed Co many acres  in the
case of Lower Lake), the greater depth is recocziende.d.
Acid Plant Vater Treatment  Facility  ("Alternative  llf).   A  closed-circui
water filtration and treatment  system would  replace  the  four  settling
du.Tpsters, main settling pond,  troughs,  and  fluid lines  currently  used

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by Asarco.   The  system would include leak detection and secondary
containment  features.  Existing and proposed sediment-drying areas  would
be equipped"  with liners and containment capability.

Once the existing settling basir.s and lines are removed, excavation of
underlying and adjacent soils would proceed.  Results of soil leach
tests indicate that  these soils should be excavated down to the coarse.
ground water-bearing gravels (20-22 feet), if practicable.   This
modification of  the  FS Report's Alternative lid is based on the
knowledge chat fresh water cocir.g ir.to contact with soils under the acid
plant fails  co meet  federal drinking water standards, regardless of
depth.  The  sace results also show that soils under the acid plar.t
exhibit characteristics of E? coxicity.

Excavated soils  would await saelting alongside the ore piles and be
treated to prevent fugitive emissions.

Thcrr.ock Lake fAlternative It*}.  EPA's preferred alternative consists of
excavating the remaining bottom sediments, stockpiling  them temporarily
alongside the ore  piles, and smelting them.

In 1936, Thorr.ock Lake was drained and replaced with a  steel tank,
complete with a  liner, leak detection system, and  secondary contair-Tient
and recovery capabilicy.  Dry sediments resain in  the existing
depression.  EPA has classified sediments of surface impoundments
(including former impoundments) at all lead smelters as hazardous wastes
that muse be removed and treated or disposed of safely.  The preferred
treat=enc of Thornock Lake sediments  is to  smelc  them  in the same manner
as for dried sediments from Lower Lake.   Smelting  these wastes  would
enable Asarco Co recover small amounts of  lead and other metals, but
more iaporcancly.  ic will immobilize  the  remaining arsenic  and  metals
within slag  produced in the process.  A modification of this alternative
would be to  dispose  of Che sediments  ac a  licensed hazardous waste
facility.

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       Depth  of excavation would be determined as for Alternative 4a (for Love:
       Lake):   excavate  to cwo feet below the artificially deposited layer of
       sediments.

       The pond floor would be lined with bentonite or an impermeable membrane
       (fabric)  if  it is  to be used to receive eoergency overflow.
II.   BACKGROUND ON' COMMUNITY INVOLVEMENT

      EPA added the East Helena site to the National Priorities List (NPL) of
hazardous waste sites in 1983.  In May 1984. £?A completed a Community
Relations Plan for the area, and the following month held a public meeting to
explain the upcoming site  investigation and answer citizens' questions.

      Most of the other community involvement activities prior to 1987 focused
on lead and its potential  effects on human health.  For instance, the Montana
Department of Health and Environmental Sciences  (MDHES) and.the National
Centers for Disease Control  (CDC) conducted a blood lead study in 1975.  The
Lewis and Clark Count-/ Health Department conducted another one in 1983. with
funding from EPA.  Asarco  conducted a third study in 1987.  Community  outreach
activities led by state and  local agencies reflected this concern about lead.

      Results of Phase I and Phase II of the site investigation, completed in
1937 and 1989. indicated that high levels of arsenic and cadmium, as well as
lead, exist in East Helena soils and water.  E?A broadened  the scope of
material it presented to the public to include  this information, and increased
the frequency of public contact.  For each phase of the site  investigation,
£?A conducted a public meeting and published a  fact sheet  to  present study
results.  EPA, MDHES. and  Asarco also met with  members  of  the  press.   In
addition, MDHES published  Progress Reports  that  included  information about  the
Ease Helena sice, and sent a letter Co Ease Helena  citizens  outlining
precautions for use of garden vegetables.  At EPA's request,  in  June  1988

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 Mayor Larry Moore established a citizens' advisory group that has met several
 tines.

       The  most recent community relations activity was the public meeiir.g of
 September  12.  1989,  at which EPA.  MDHES. and Asarco described the preferred
 alternatives for addressing contanination of the process ponds.  Copies of the
 Proposed Plan were available at this  meeting, for those who were not on the
 mailing list.   Topics discussed at this meeting are included in the suz=ary of
 cor.-7er.ts received during the public concent period.
III.  SUMMARY OF QUESTIONS  AND  COMMENTS RECEIVED DURING THE PUBLIC COMMENT
      PERIOD  AND EPA'S RESPONSES  TO  THOSE COMMENTS

      From  August 31 to September 20,  1989, EPA received public coc.T.er.ts on
the FS Report and the Proposed  Plan.   EPA. KDHES . and Asarco also held a
public meeting -on September 12  to describe the preferred alternatives and
answer any  questions from residents.   Twenty people  attended the meeting, mos;
of whom  represented public  agencies,  contractors, or potentially responsible
parties.  In  addition to comaent's taken from this meeting,  this summary
includes material from letters  submitted on behalf of ARCO, Asarco,  and  the
East Helena Superfund Task  Force.  Consents are categorized by  the
following topics:                        •

      •     Treatment of Lower  Lake  fluids;
      •     Implementation  time;
      •     Extent of excavation;
            Retention of speiss pond for emergency overflow;  and
      •     Public comment  period.

      Only  comments that EPA has  responded to  are  given below;  comments  that
Asarco or its subcontractor responded to are included  in the  meeting summary
(Attachment B) .

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       r.c  of  Lover  Lake  Fluid;?

      AC the  September  12  meeting, Asarco and E?A voiced their different
preferences for  treatment  of  Lower Lake fluids.  Asarco would like to
implement  Alternative 5s  instead  of Alternative &a. E?A's choice.  Under
Alternative 5s,  Lower Lake fluids would be treated in place, rather than
pretreated ac a  facility  that would be built for that purpose and then
discharged to the East  Helena POTV.  Alternative 5s is less expensive than
Alternative &a.   (Other  aspects of the remedies are the sa_T.e.)   Sir.ce the
meeting, a Task  Force member  (who is also an American Che-et emplovee). Ar.CQ's
attorneys, and Asarco have sent EPA letters that state a preference for
Alternative 5s instead  of  4a.

Ccrr-T.er.t:    (Task Force; Asarco;  Parcel, Mauro, Hultin-& Spaanstra, for A-3.C3) :
            It seems reasonable to attempt the in-situ treatment as long as
            Asarco  agrees  to  install a treatment facility if such treatment
            does not reduce contaminants to State and Federal standards.

            In-situ treatment offers the advantages of lover costs,
            simplicity,  on-site treatment, and reduction of risk to the
            environment.   The U.S. Bureau of Mines and Montana  College  of
            Mineral Science and Technology have demonstrated  the method's
            technical feasibility on a laboratory scale, and Asarco would.
            conduct a pilot-scale field test before attempting  full-scale
            application.   Successful in-situ treatment also could serve as a
            model for application ac other sites.

Response:   EPA  and the  State of  Montana orginally concluded  chat Alternative
            Aa would protect  human health and  the environment  to a  greater
            degree  than would the other alternatives.  This  conclusion  was
            reached in  the absence of an independent  assessment of  the
            prospects for  successful in-place  treatment,  in the absence of a
            proposal from  Asarco  to conduct large-scale  treatabiliry  tests,
            and  in  the  absence  of public involvement.  However, on September

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             20,  Asarco provided the State and EPA with a plan for conducting
             pilot-scale tests of the proposed method, and acknowledged che
             need for a back-up plan should those tests prove- unsuccessful .
             Also,  E?A has  taken Into consideration the assessments perfc—.ed
             by  the U.S.  Bureau of Mines and the Montana College of Mineral
             Science and Technology.  For these reasons, E?A  has reconsidered
             Asarco 's proposed treatment for Lower Lake fluids and changed its
             preferred alternative to Alternative 5s, Asarco's choice, buc wil
             keep Alternative &a, E?A's original preference,  as  che conringen;-
             plan should in-situ treatment fail to reduce the contaminants- c:
             concern to specified levels.
IT? 1 errgr. 1 3 t i on    me

      Comments  regarding  impleser.tation tiae concerned both  tiae  for smelting
and tiae for  repiaceaent  of  the speiss pit.

Comment:    (Asarco):   EPA requires repiaceaent of  the speiss  pit within r-o
            years.   Asarco agrees with the recoooended action  but recomaends
            that  it  take  place in 1992, when Asarco has  scheduled major
            renovations to the dross reverberatory  operation.   Replacing the
            speiss pit  as part of this larger project would  xinimize
            production  downtiae, and make best use  of construction  equipment
            and manpower.

Response:   Replacing the speiss pit according to  EPA's  schedule  assures that
            all known source problems will be corrected  at the same tiae.
            Installing  a  steel liner, might serve as an  interim measure co
            eliminate leakage of fluids from the speiss  pit.  However, EPA
            thinks it is  important to weigh the costs  of replacing  the speiss
            pit ahead of  Asarco's proposed schedule against the costs  of
            interim  measures.

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Comment::     (Mayor Larry Moore):  Why do the estimates  of required smelting
             time differ?

Respor.se:    There are  cvo  reasons for the different smelting times.   Asarco.
             which performed the Feasibility Study,  originally didn't plan to
             excavate as deeply as EPA believes is necessary.  Therefore,
             Asarco's estimated volume of soils to be excavated and smelted is
             less than  EPA's.  Consequently, the estimated time for smelting
             the scalier amount is shorter than EFA's rise.  Also, the soil
             being excavated contains boulders and cobbles, which are T.ore
             difficult  to handle than sand.

Comment:     (Asarco) :  EPA estimates that the quantity of materials to be
             excavated  is over 50,000 tons.  This projected quantity represents
             a  little more  than 20% of the smelter's annual capacity (normal
             capacity is 20,000 tons per month, or 240,000 tons per year).  The
             material to be excavated contains a low concentration of expected
             recoverable metals, and is considered "dead charge."  Smelting
             more than  0.3% dead charge (100 tons per month) has produced blast
             furnace upsets which.in turn, have created air quality problems.
             Keeping the dead charge to 0.5% of total charge means that it will
             take 500 months, or over &1 years, to smelt 50,000 tons.

Response:    EPA's estimation of smelting times was based  on  the assumption
             that the times given in Asarco's  FS are accurate.  The  information
             concerning problems that would result from using  more than 0.5%
             dead charge does not appear to have been considered  in  the FS.

Ccirjrent:     (Asarco):  Soils scheduled to be  removed from the acid  plant  water
             treatment  facility and soils that have already  been  excavaced from
             the speiss area contain gravels,  cobbles,  and boulders  that  would
             have to be crushed prior to smelting, thereby increasing  the
             aaounc of  time required for the overall remedy.   Asarco believes
                                       10

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             that  these  large materials should be separated, washed,  and stored
             on-site  rather than saelted.

Response:    £?A agrees  with Asarco on this matter.

Extent of  Excavation

      Cocaenters  recommended less excavation at Lower Lake, the speiss
granulating  pit and pond, and the acid plant water treataer.t facility thar. I?A
had outlined in the Proposed Plan.

Coir-Tent:     (Asarco; Parcel, Mauro, Hultin & Spaanstra, for ARCO):   E?A's
             Proposed Plan recommends removal of Lower Lake artificially-
             deposited sludge, plus an additional two-foot  layer.  The FS
             Report recommended removing the sludge plus a  one-foot layer.
             Asarco does not believe the removal of additional material has
             been  technically Justified by EPA.  Concentrations of leachate
             from  samples of the underlying material pass the E? toxicity rest
             and meet primary drinking water standards.

Response:    The layer of bottom sedizents at Lower Lake is a hazardous wasze
             and oust be removed and created.  In addition, Asarco's RI data
             show  that even at two fee: below this layer, the sediments concain
             up to 770 mg/kg arsenic and 2,500 mgAg lead.  The  E? toxicity
             tests are conducted under laboratory conditions; under natural
             conditions, fresh water coming into contact with contaminated
             sediments will not necessarily meet the same standards.

Coraaent:     (Asarco; Parcel, Mauro, Hultin & Spaanstra, for ARCO) :   EPA's
             Proposed Plan recommends removal of sediment  in  the speiss  pit and
             pond  area to 20 feet, if practical.  However,  the  FS considered
             excavation  of the upper six feet of sediments, not 20, because
             arsenic and metals concentrations in  leachate  from sediment
             samples at  six to 20  feet were below  drinking  water standards.
                                      11

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            Although Asarco  has  already Implemented deep excavation underneath
            Che  speiss  pond  replacement tank area, it does not appear that ar.v
            significant benefit  has been obtained by doing so.

Response:   [EPA did not respond directly to this question.]

Comment:    (Asarco; Parcel,  Mauro, Hultin & Spaanstra, for ARCO):  EPA's
            Proposed Plan recomcends  excavation to 18 to 20 feet  at the acid
            plant water treatment facility, if practical.  However, the ~S
            Report  called for removal of the upper five feet  of sedirer.ts
            only, plus  capping or paving the surface to prevent water fro:?.
            moving  down through  underlying sediment.
Resrcr.se
E?A recomaended excavation to IS to 20 feet because soil sa.T.slir.g
and analysis showed  that soils in this area exhibited
characteristics of E?  toxicity.  However, this recommendation was
based upon results from only one drill hole.  More holes will be
drilled before excavation takes place, to better determine the
voluae of soils requiring treatment and  the depth of excavation.
Ccrz=er.t:    (Asarco):   Practical  limits  to  excavation  at  the  acid  plant water
            treatment  facility must  be  taken  into  consideration.   These limits
            include  such  items as the  structural integrity of buildings in  the
            area  and the  depth to which  normal  excavating equipment  can reach
            co effectively excavate  soils.

Response:   EPA agrees  chat practical  limits  to excavation must be considered.
            Nevertheless,  we do not  agree  that  such  limits can be  defined as
            "Che'  depth  Co  which normal  excavating  equipment can reach to
            effectively excavate  soils."  EPA is withholding judgment on  this
            issue until che remedial design phase  begins.
                                       12

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 rtecencion or Speiss   ,d for Eaerzencv Ov»rfTov

 Comment:   .  (Asarco):  Asarco would like to retain the existing speiss
             granulating  pond for emergency overflow purposes.  The por.d
             nonnally would remain dry, but it would provide additional holding
             capacity (beyond that offered by the steel tank) if the system
             malfunctioned.  After the malfunction was corrected, the water
             would be aoved out of the pond and back to the new tank.  Keeping
             the  por.d vould scan no excavation could occur underneath it.'but
             use  of an  icper=eabie liner would stop .rain  or other fluiis  frc-
             leaching aetals in the underlying soils.

Response:    EPA  cannot approve this request.  Soils under the speiss pond and
             pit  are the  most significant contributors to ground water
             contamination north of the plant.  The reason for putting the
             process ponds work ahead of the other operable units is to effect
             a  source removal without unnecessary delay,  and leaving these
             highly contacinated materials in place would be inconsistent with
             long-tera  goals for cleaning up the site.

Public Corr.T.ent Period

Corrjr.er.t:     (Asarco):  Is there any mechanism for extending  the public corr.-r.ent
             period?

Response:    A  decision on extending the public comment period would depend  on
             the  source of the request.  If the request cace  from  the  general
             public,  an extension would be possible.   Another  factor would  be
             whether new  information was provided  that could  affect decisions.

Comment:     (Parcel, Mauro, Hultin & Spaanstra. on behalf  of ARCO):   ARCS
             received a copy of the Proposed Plan  from EPA  on September  12,
             1989,  the  day of the public meeting.  The RI/FS  Report did  not
             arrive until September 15.  Also, the RI/FS  Report  was not
                                       13

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            available in che EPA Region VIII library (Denver. Colorado) or
            other information  repositories in the Denver metro area.  Nor was
            notice of the RI/FS or of the East Helena meeting published in the
            Denver metro area.  Therefore, ARCO requests that E?A extend the
            public comment period to at least October 6, 1989. to allow time
            for careful consideration of  these documents.

Response:   EPA. the State of  Montana, Asarco, and the  corasunity of  East
            Helena ail agree in principle on the major  corspcr.er.ts of -he
            remedial alternatives.  Therefore, EPA considers  the allotted  21
            days Co be adequate.

Cc.TJ7.ent:    Did EPA announce the September 12 public meeting?

Respor.se:   A public notice was printed in the newspaper on  August  30  and  31,
            and on September 1.  There was also an announcement  in  the
            newspaper.  Copies of the Proposed Plan, which also  announces  the
            meeting, were mailed directly to about 200  people  currently on the
            mailing list.  There are also copies of  the Proposed Plan at  EPA
            and at the librarv.

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                                 Attachment A

                 Chronology of Conaunity Involvement Activities
after  1975:



1983:



9/82:



5/84:

6/6/84:


6/87:


6/11/37:


1/83:


2/33 :


3/88:


3/2/88:

5/88:


6/88:



8/88:

9/88:
MDHZS conducted public awareness  campaign  to  present  results of
1975 blood lead study and to  suggest precautions  against  lead
exposure.

MDHES Solid and Hazardous Waste Bureau established citizens'
advisory committee to prepare residents for another blood lead
study.  The committee held several  meetings held  in late  1933.

Montana Health Board. Asarco,  City  of East Helena.  State  Hig'-vay
Department, and MDHES met to  discuss plan  for reducing  airborne
lead in East Helena to below  the  federal standards.

EPA completed Community Relations Plan.

EPA held public meeting at East Helena Firemens'  Hall to  explain
upcoming site investigation and to  receive comnents and questions.

EPA issued Fact Sheet on Phase I  of the RI;  Phase I included
soils, vegetation, and livestock  studies.

EPA and Asarco held public meeting  at East Helena Firenens'  Hall
to present findings of Phase  I.

EPA. City of East Helena. MDHES.  and state and local  agencies held
public meeting.

EPA. City of East Helena, MDHES,  and state and local  agencies held
public meeting.

MDHES issued Progress Report  (update on recent studies and
results).

EPA, MDHES, and Asarco held press meeting.

EPA, MDHES, and Asarco met with TV  and newspaper reporters to
discuss the status of studies in  East Helena.

East Helena Mayor Larry Moore, at EPA's request,  established
citizens' advisory group; the first meeting was held the sane
month.

Citizens' advisory group met.

MDHES sent letter to population of  East Helena outlining
precautions for use of garden vegetables, to reduce  ingestion of
metals and arsenic.
                                      15

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4/89:       Citizens' advisory group met.

4/89:       EPA and MDHES  issued Face Sheec on Phase II of the RI; Phase II
            included vegetation, soils, livestock, and ground water.

4/27/89:    EPA held public meeting at Radley School, East Helena, to present
            results of Phase II RI.

8/89:       EPA and MDHES  issued Proposed Plan for the Process Ponds Operable
            Unit.
8/21 to
9/20/39

9/12/89:
Public comment period on Proposed Plan.

EPA held public meeting in East Helena Firecer.s' Hail  to preser.r
preferred alternatives for the Process Ponds Operable  Unit.
                                       16

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      Attachment B

Susaary of Public Meeting
 Held September 12.  1989
            17

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                                MEETING SUMMARY

                      SEPTEMBER 12. 1989,  PUBLIC MEETING

                             EAST HELENA,  MONTANA
Location:

Start Time:

Finish Time:

Participants;
Subject:
Firemen's Hall

7:30 p.m.

9:30 p.m.

Scott Brown (EPA);  Eric Finke (EPA);  Jon Nickel (Asarco
Incorporated); Bob  Miller (Hydrometrics);  Greg Mullen
(MDHES); Jane Stiles (MDHES); Larry D.  Moore (Mayor,  East
Helena); Dave Bunte (CH2M Hill);  Eric Palmer (Task Force)
Holly Luh (Senator  Baucus'  office);  Grant Sasek (The
Independent Record); Ken Vreeling (Asarco Incorporated);
Patty Lee (ICF);  U.P.  Buland; Dolly Lamping; Jay Reardon;
Sandy Stash;  Andrew Zdnak;  Tom Rolfe; B.J.  Mazurek

Proposed Plan for Process Ponds Cleanup  at East Helena
Smelter Site
Opening Statements

      Scott Brown of the U.S. Environmental Protection Agency opened the
meeting by announcing chat, after considerable study of possible actions,
cleanup work on the process ponds was about to begin.  He emphasized that the
State, Asarco. and EPA all had cooperated in coming up with solutions to the
site contamination.

      Mr. Brown then introduced the following persons:  Greg Mullen, who
recently joined the staff of the Montana Department of Health and
Environmental Sciences (Solid and Hazardous Waste Bureau); Jon Nickel of
Asarco Incorporated; Larry Moore. Mayor of East Helena and East Helena
Superfund Task Force member; and Eric Palmer of the East Helena Superfund Task
Force.  Mr. Brown urged citizens to contact Moore, Palmer, or any of the three
other Task Force members, stating that they are the residents' liaison with
EPA and the State on Superfund activities.

      Mr. Brown informed the audience that the meeting fell In the middle of
the public comment period for the Proposed Plan, which he referred to as the
"Reader's Digest" of Asarco's Feasibility Study.  (Copies of the Proposed Plan
had been mailed directly to the approximately 200 people on Che Bailing  list,
and extra copies were available at the meeting.)  He stated that Che Proposed
Plan described EPA's recommended alternatives from the Feasibility Study, as
well as some other plausible alternatives.  He encouraged people Co comment on
these alternatives until September 20, the end of the public comment period.
While EPA, the Scate, and Asarco were mostly in agreement, he added, there
                                                          F

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 were  some differences of opinion that would be discussed in the next part  of
 the meeting.

       Due to the small size of the group,  Mr.  Brown asked that people raise
 questions at any time rather than save them for the end of the meeting.


 Overview of the Site's Five Operable Units

      Mr. Brown listed the East Helena site's  five operable units:   process
 ponds  (the subject of this meeting); ground water; surface water, soils,
 vegetation,  livestock, fish, and wildlife; ore storage areas; and slag pile.
 He stated that EPA had separated the process ponds operable unit from the
 others for the first Feasibility Study;  the other units would be covered
 together in a Comprehensive Site-Wide Feasibility Study, to be completed this
 winter.  The process ponds should be treated first, he said, because they
 constitute a source of contamination to  shallow ground water in East Helena.

      Next,  Mr. Brown briefly described  the four subunits of the process ponds
 and illustrated his talk with slides of  Lower  Lake, the speiss granulating pit
 and pond, the acid plant water treatment facility, and Thornock Lake.  Mr.
 Brown noted that while these subunits differ from each other, they all
 contribute arsenic and metals Co the ground water by seepage and leakage of
 process fluids.  It is important, he stated, to dry the removed sediments on
 special drying pads so that further seepage to underlying soils will not
 occur.

      Mr. Brown re-stated that because the process fluids are the source of
 ground water contamination, they must be cleaned up first.  The general theme
 behind the cleanup alternatives is to isolate  the fluids from the soils,
 replace existing fluid bodies with tanks or install leak-proof liners,  and
 excavate contaminated soils beneath them.
Proposed Plan for Cleanup of the Process Ponds

      Mr. Brown proceeded to summarize the recommended alternatives  for each
of the process ponds' subunits.

      EPA's and the State's (but not Asarco's) preferred alternative  for Lower
Lake is to replace the lake with two million-gallon storage tanks, excavate
the sludge layer (containing high levels of arsenic and lead) plus two feet of
wet sediments below the layer, dry the sediments on lined pads,  and  smelt  the
sediments.  Water from Lower Lake would be pretreated for discharge  to the
East Helena Publicly Owned Treatment Works (POTU).  As a sidenote, Mr. Brown
explained that Che sludge layer must be excavated by law.  The  additional  two
feet to be excavated is a safety margin; soil leach tests indicate chat water
passing underneath the sludge layer will meet drinking water  standards.
Although it would be safest to excavate all soils underneath  Che sludge,  the
cost would be about $80 million instead of $8.5 million.

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      According  to Mr. Brown, the major part of the cleanup cost with  the
 above alternative arises from construction of a treatment facility to  reduce
 fluid contaminant levels to acceptable levels.

      EPA's and  the State's preferred alternative for the speiss granulating
 pit and pond is  to replace them, excavate soils "to the practical limit,"  and
 smelt those soils.  Again, Mr. Brown explained that soils should be excavated
 to the limit because structures will be built at the site; if it should turn
 out that not enough soil was excavated the first time, these structures would
 have to be removed prior to additional excavation.  It would be more efficient
 to remove as much contaminated soil as possible the first time.  Because the
 volume of soils  at this area is much less than that of Lower Lake, the
 additional cost  is not prohibitive.  Total cost:  approximately $700,000.

      For the acid plant water treatment facility, EPA and the State recommend
 replacing the leaky settling dumpsters with a closed-circuit filtration
 system, excavating the soils to practical limits, and smelting the soils.   The
 cost would be about $1.9 million.

      For Thornock Lake, EPA and the State recommend excavating the sludge
 layer plus an additional two feet, smelting the sediments, and lining the
 cavity to prevent any collected fluids from contaminating the underlying
 soils.  Cost:  $19.000 to $52.000  ($52.000 with the liner).

      Mr. Brown  repeated that while the above alternatives are EPA's choices,
 other alternatives do exist.  Greg Mullen said that the State of Montana
 basically agrees with EPA's choices.


 Report and Comments by Asarco Incorporated

      Jon Nickel explained Asarco's preferences for the process ponds and also
 highlighted his  talk with slides.

      Mr. Nickel said that Lower Lake had originally been  formed  to collect
 stormwater runoff and to contain process waters, particularly  from Asarco's
 zinc fuming operations.  Because the zinc fuming operations ended  in  1982, it
 was now possible to replace the 11 million-gallon  lake with a  pair of million-
 gallon tanks.  With EPA's approval, Asarco has begun construction  of  these
 tanks, plus secondary containment  facilities.  Asarco agrees with  EPA on  the
 extent of excavation for Lower Lake, and on the choice of  smelting to destroy
 metals in the sediments.

      However, Asarco would prefer to treat process water  in-place rather than
 construct a separate treatment facility.  Mr. Nickel cited  the  following
 advantages to in-place treatment:  1) no treatment  facility would have  to be
built; 2) the East Helena POTV would not have to  accommodate discharge  from
 the Lower Lake subunit; and 3) successful in-place  treatment would lower  costs
by about $5 million (from $8.5 million to $3 million).  Asarco plans  to ask
 EPA and the State for additional time to test in-place treatment methods;  if
 successful, they would like to implement such treatment  for Lower Lake.   If
 test results are unsuccessful, Mr. Nickel said, then  the  only  alternative is

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 to  treat water In a special facility before  discharging to the  East  Helena
 POTW.

      Another area in which Asarco differs from EPA and the State is
 implementation time.  Mr. Nickel said Asarco feels that the four years  cited
 by  EPA is not enough time to include smelting the volume of sediments
 involved.  Asarco recommends a phased approach to cleanup with  four  years
 allowed for all work except the smelting,  and additional time for the
 smelting.

      According to Mr.  Nickel, speiss is a copper-bearing substance  that comes
 out of the furnaces in a molten state and turns into a sand-like material
 after being cooled with water.  Speiss contains arsenic and antimony,  which
 enter the process waters.  Mr. Nickel admitted that although the pit and pond
 are currently lined, management practices have resulted in leakage of process
 fluids.  He said Asarco agrees that the speiss granulating pit  and the pond
 should be replaced, and EPA and the State have given their approval  for Asarco
 to begin replacement.

      Asarco differs from EPA and the State  in two aspects of the remedy for
 the speiss pit and pond.  First, Asarco recommends that a portion of the
 existing speiss pond be retained as emergency overflow.  However, keeping the
 pond would preclude excavation below it.  Second, as with Lower Lake,  Asarco
 feels more time is necessary for smelting.  Mr. Nickel explained that the
 soils Asarco has excavated so far near the speiss pond include  boulders and
 cobbles--material that is time-consuming to  process--rather than just sand.

      For the acid plant water treatment facility, Asarco agrees with EPA and
 the State that the existing settling tanks should be replaced with a closed-
 circuit filtration system.  Mr. Nickel said excavation would be limited
because of the presence of structures that are being used.  He also repeated
 the need for additional time to smelt soils.

      Mr. Nickel stated that, as with the other process pond areas,  more time
 is needed to smelt Thornock Lake sediments.

      [Here, Mr.  Brown introduced Bob Miller (Hydrometrics, Asarco's
contractor), Jane Stiles (MDHES:  Community Relations), Eric Finke  (Mr.
Brown's supervisor at EPA), Dave Bunte (CH2M Hill, EPA's contractor), and
 Patty Lee (ICF:  Community Relations).]


Public Comments and Questions

      Mr. Brown invited the audience to comment or ask questions.

      Mr. Nickel interrupted to explain an aspect of Asarco's  plans for the
speiss granulating pit and pond.  Asarco plans to replace  its  "dross reverb
furnace"  (which includes the speiss granulating area)  in  two or  three years.
EPA's estimated implementation time for replacing the  pit  and  pond  is  1.5
years.  Mr. Nickel said it would make sense to wait on replacing the pit;  if

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 the pit was replaced according to EPA's schedule,  it would have  to  be  removed
 when  the other work is done.
Q:
Eric Palmer (Task Force):   What  is  the  in-place treatment proposed for
Lower Lake?  After the water is  clean,  what happens to it?
A:    The water is treated to meet certain standards and then left in place.
      The arsenic in the water settles to the bottom of the pond and is
      excavated with the other sediments for smelting.

Q:    Would the clean water be discharged to the POTW?   Would Lower Lake stay?

A:    With in-place treatment, Lower Lake would stay as a natural surface
      water depression.  Water would not go to the POTW.  The elevation of
      Upper Lake, which is fresh water, is slightly elevated compared to the
      surface elevation of Lower Lake.  Pumping the water out of Lower Lake to
      treat and discharge it would only allow Upper Lake water to flow in, so
      the water may as well stay there in the first place.  It'll be cleaned
      to remove the metals, and Lower Lake may eventually go back to its
      natural state.

Q:    Grant Sasek (The Independent Record):  The four sites you're presenting
      are all wet areas.  Are there other major wet sites that could be a
      problem?

A:    The four subunits previously described are the only known major sources
      of contamination.

Q:    Grant Sasek:  Do the dry areas have much impact?

A:    Assuming that "dry areas" refers to soils, the degree to which such
      areas could affect contamination depends upon their potential to carry
      metals down from percolation of water through the sediments.  A "head,"
      or force, must be present to move metals through  the soil into the
      ground water.  That force has always been water overlying soil or
      sediment.  For example, some water that was contaminated by ore
      processes has moved through the soil and into the ground.water.  The
      objective of this Proposed Plan is to remove such forces.

Q:    Larry Moore:  On the Lower Lake preferred alternative  (Alternative  4a),
      how much water will be discharged to the city water system?

A:    Lower Lake currently holds 11 million gallons.  One of  the  tanks  to be
      installed will hold one million gallons; the other  tank will  be used
      just for emergency holding.  Therefore, there will be at least  10
      million gallons Co discharge.  Unfortunately, as  soon as water  is  pumped
      out of Lower Lake, new water (from Upper Lake) cones in Co  Cake  its
      place.

      Also, there is a process water gain of approximately 25 to  SO gallons
      per minute (gpm), which translates to approximately  70,000  gallons per
      day.   If nothing is done with chat gain, which cones from  several

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      sources In the plant, there will be an increase of water needing
      treatment, in addition to the Lower Lake  fluids.

Q:    Once these projects are completed,  how much will arsenic and lead levels
      be reduced?

A:    If the right conditions exist,  arsenic is naturally removed from the
      aqueous phase, or water phase,  as the ground water moves north from the
      plant.

      Jon Nickel introduced Ken Vreeling, who works at Asarco's plant and is
involved with the water-handling system.

      Scott Brown summarized the following points of disagreement between EPA
and Asarco.  Asarco feels that more time  is required for smelting at all four
process areas.   For Lower Lake, Asarco recommends in-place treatment of
process fluids rather than treatment at a special facility followed by
discharge to the POTU.  For the speiss area, Asarco would like to retain half
the pond, and they would like more time for pit replacement.   Mr. Brown also
acknowledged Asarco's statement that the  acid plant includes  a number of
structures whose presence should be accommodated during excavation.

Q:    Jon Nickel:  Is there any mechanism for extending the public comment
      period?

A:    Whether or not to extend the comment period would depend on where the
      request came from.  If it came from the general public, an extension
      would be possible.  If the comment  came from Asarco, the extension
      probably would not occur.  Another  factor would be whether new
      information was provided that could affect decisions.

Q:    Did you announce the public meeting?

A:    A public notice was printed in the  newspaper on August  30 and 31, and on
      September 1.  There was also an announcement in the newspaper.  Copies
      of the Proposed Plan, which also announces the meeting, were mailed
      directly to about 200 people currently on the mailing list.  You can add
      yourself to the list by contacting Patty  Lee.  There are also copies of
      the Proposed Plan at EPA and at the library.

Q:    Why aren't more people here?

A:    Simultaneous scheduling of a school board meeting and an election
      probably drew some people who would otherwise have  attended  this
      meeting.

Q:    Mayor:  Why do the estimates of required smelting tine  differ?

A:    There are two reasons for Che different smelting tiaes.  Asarco, who
      performed the Feasibility Study, didn't originally  plan to  excavate as
      deeply as EPA feels is necessary.  Asarco's  estimated volume of soils  to
      be excavated, and thereafter smelted,  is less  than  EPA's.   Consequently,

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      the estimated time for smelting the smaller amount  is  shorter than  EPA's
      time.  Also, the soil being excavated is not just  sand--it contains
      boulders and cobbles, which are more difficult to  handle.

Q:    Does the sediment contain enough metals to make smelting profitable?

A:    Smelting these sediments is not a profitable operation.   Each ton of
      material that goes through carries about an ounce  of silver in the  slag.
      pile.  Starting with material that contains less than an ounce of
      silver,  as is probably the case with these sediments,  actually results
      in money being lost.   Some of the smelting cost is profit loss, rather
      than engineering cost, but it's nevertheless a cost.  On the other hand,
      smelting is a cost-effective method of treatment.   The other alternative
      is to send it away to a hazardous waste material storage area, and the
      cost benefits of smelting outweigh those of sending it out.

      With no  further questions being asked by the public, Mr. Brown concluded
the meeting at 9:30 p.m. •

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