PB98-964023
                                EPA 541-R98-103
                                November 1998
EPA Superfund
      Record of Decision:
      Stauffer Chemical Co.
      (Tarpon Springs) OU 1
      Tarpon Springs, FL
      7/2/1998

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                                      5  9    0001
          Record of Decision

        The Decision Summary
           Operable Unit 1
 Stauffer Chemical Tarpon Springs Site
Tarpon Springs, Pinellas County, Florida
            Prepared By:
 U.S. Environmental Protection Agency
              Region 4
          Atlanta, Georgia

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                                                                         5   9      0009
                               RECORD OF DECISION


                                   DECLARATION

 SITE NAME AND LOCATION

 Stauffer Chemical Tarpon Springs Site
 Tarpon Springs, Pinellas County. Florida

 STATEMENT OF BASIS AND PURPOSE

 This decision document presents the selected remedial action for Operable Unit 1 at the Stauffer
 Chemical Tarpon Springs Site in Tarpon Springs, Pinellas County, Florida, which was chosen in
 accordance with the Comprehensive Environmental Response Compensation and Liability Act of
 1980 (CERCLA), as amended by the Superfimd Amendments Reauthorization Act of 1986
 (SARA), 42 U.S.C. § 9601 et seq.. and the National Oil and Hazardous Substances Pollution
 Contingency Plan (NCP), 40 CFR Part 300. This decision is based on the Administrative Record
 file for this site.

 The State of Florida, as represented by the Department of Environmental Protection (FDEP), has
 been the support agency during the Remedial Investigation/Feasibility Study process for the
 Stauffer site.  In accordance with 40 CFR § 300.430, FDEP, as the support agency, has provided
 input during this process. Based upon comments received from FDEP, it is expected that
 concurrence will be forthcoming; however, a formal letter of concurrence has not yet been
 received.

 ASSESSMENT OF THE SITE

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

 DESCRIPTION OF THE REMEDY

This is the first of two operable units planned for the Site.  This operable unit addresses the source
of the soil and groundwater contamination by treating and containing the source material.  The
second operable unit will address the contaminated groundwater in the surficial aquifer. The
diesel fuel product identified during the groundwater investigation will be addressed under the
State of Florida's Underground Storage Tank Program.

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                                                                           5   9       0003
 The major components of the selected remedy include:

 •     Limited excavation of radiologically and chemically contaminated material/soil which
        exceed Residential Cleanup Standards.

 •     Consolidation of contaminated material/soil in the main pond area, slag area, and/or other
        areas on-site. Top Cover Caps which meet the Florida Administrative Code § 62-
        701.050 will be placed over the Consolidation Areas.  The movement of contaminated
        soil/waste will be limited to minimize the generation of fugitive dust and to prevent the
        creation of additional threats to human health and the environment.

 •     Institutional Controls must be placed on the site.  Institutional controls must include deed
        restrictions, land use ordinances, physical barriers, and water supply well permitting
        prohibitions. These restrictions will limit access to the site and prohibit the disturbance of
        the remedy.

 •      In-situ Solidification/Stabilization of pond material and contaminated soil below the water
        table will be required in the consolidation areas on-site. The consolidation areas will be
        delineated  in the Remedial Design Report.

 The total present worth cost for the selected remedy as presented in the Feasibility Study is
 $9,356,000.  The construction of multiple consolidation areas may increase the present worth cost
 of this remedy.

 STATUTORY DETERMINATION

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

 Because this remedy will result in hazardous source material remaining on-site above health-based
 levels, a review will be conducted within five years after the commencement of remedial action
 and every five years thereafter to ensure the remedy continues to provide adequate protection of
 human health and the environment.
RICHARD D. GREEN               DATE
WASTE DIVISION
DIRECTOR

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                                                               i;  9      OC
                                                               w>  X

                            TABLE OF CONTENTS

 1.0    SITE LOCATION AND DESCRIPTION 	1

 2.0    SITE HISTORY AND ENFORCEMENT ACTIVITIES	1

 3.0    HIGHLIGHTS OF COMMUNITY PARTICIPATION	6

 4.0    SCOPE AND ROLE OF ACTION 	6

 5.0    SUMMARY OF SITE CHARACTERISTICS	6
       5.1    Physiography and Topography	6
       5.2    Geology	7
       5.3    Hvdroeeology  	7
       5.4    Surface Water and Drainage	9
       5.5    Spjl  	9
       5.6    Summary of Site Contaminants	10
                  5.6.1  Substances Detected in Soil	10
                  5.6.2  Substances Detected in Surface Water and Sediment	11
                  5.6.3  Air Monitoring 	12

6.0    SUMMARY OF SITE RISKS	,	22
       6.1   Risk Assessment Overview - Chemical	22
       6.2   Human Health Risk  	24
                  6.2.1   Chemical	24
                  6.2.2  Radiological Overview and Assumptions	25
       6.3   Summary of Exposure Scenarios  	26
                  6.3.1   Summary of the Chemical  Exposure Scenarios	27
                  6.3.2  Summary of Radiological Exposure Scenarios	28
      6.4   Ecological Risks	33
      6.5   Cleanup Levels	35

7.0   DESCRIPTION OF REMEDIAL ACTION ALTERNATIVES	36

8.0   SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES	42
      8.1    Comparative Analysis - Nine Criteria  	42
      8.2   Threshold Criteria	43
            8.2.1   Overall Protectiveness of Human Health and the Environment  	43
            8.2.2   Compliance with ARARs  	43
      8.3    Primary Balancing Criteria	48
                  8.3.1  Lone-Term Effectiveness and Permanence	48
                  8.3.2  Reduction in Toxicitv. Mobility, or Volume Throueh Treatment 48
                  8.3.3  Short-Term Effectiveness  	48
                  8.3.4  Implementabilitv	48
                  8.3.5  Cost 	49

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                                                                  r   c\       o i~~-
                                                                  59       U u

      8.4    Modifying Criteria  	%	49
                   8.4.1   State Acceptance	49
                   8.4.2   Community Acceptance	49

9.0   SUMMARY OF SELECTED REMEDY	56
      9.1    Major Components of the Selected Alternative	56
      9.2    Performance Standards	57
                   9.2.1   Performance Standards - Cap  	57
                   9.2.2   Performance Standards - Solidification 	57
                   9.2.3   Performance Standards - Design  	57
      9.3    Compliance Testing 	59

10.0  STATUTORY DETERMINATION  	59
      10.1    Protection of Human Health and the Environment  	59
      10.2    Attainment of Applicable or Relevant and Appropriate Requirements (ARARs)  59
      10.3    Cost Effectiveness  	60
      10.4    Utilization of Permanent Solution to the Maximum extent Practicable	60
      10.5    Preference for Treatment as a Principal Element	61

11.0  DOCUMENTATION OF SIGNIFICANT CHANGES  	61

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                                                                      5  9      0006
                                  LIST OF TABLES

 Table 5-1     Surface Soil Samples	16-17

 Table 5-2     Sediment Samples	18

 Table 5-3     Surface Water Samples	19

 Table 5-4     Pond Material Samples	20-21

 Table 6-1     Summary of Contaminants of Concern	23

 Table 6-2     Contaminants of Concern that Pose a Carcinogenic Risk	29

 Table 6-3     Contaminants of Concern with Hazard Quotient Greater than
              .01 for Pathways with a Hazard Index Exceeding 1.0	30

 Table 6-4     Comparison of Maximum Detected Concentrations
              of Lead to  ARARs	30

 Table 6-5     Scenarios Analyzed for the Radiological Risk Analysis	31

 Table 6-6     Estimated Radiological Risk Considering Major Pathways	32

 Table 6-7     Ecological Summary of the Contaminants of Concern	34

 Table 6-X     Cleanup Standards: Remedial Goals	36

 Table 7-1      Response Actions and Associated Remedial Technologies	37

 Table 8-1     Locations Specific ARARs	45

 Table 8-2     Action Specific ARARs	46

 Table 8-3     Chemical-Specific ARARs	47

 Table 8-4     Summary of Remedial Action Alternatives	50-54

 Table 8-5     Cost Comparison of Remedial Action Alternatives	55

Table 9-1     Performance Standards - Remedial Goals	58

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                                                                    5  9    .  0007
                               LIST OF FIGURES






Figure 1-1    Site Location Map	2




Figure 2-1    1993 Soil Sampling Results	3




Figure 2-2    1993 Pond and Road Sampling Results	4




Figure 5-1    Surface Water Analytical Results	13




Figure 5-2    Sediment Analytical Results	14




Figure 5-3    Sediment Core Analytical Results	15








APPENDIX A - RESPONSIVENESS SUMMARY

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                                                                          5   9       0008
  1.0    SITE LOCATION AND DESCRIPTION
 The Stauffer Chemical Tarpon Springs Superfund Site (Site) is located on Anclote Road in
 Tarpon Springs, Pinellas County, Florida. The location of the Site, taken from the U.S.
 Geological Survey (USGS) Topographic Map prepared in 1987, is presented in Figure 1-1 (not to
 scale). The Site is situated along the Anclote River, which flows into the Gulf of Mexico
 approximately two miles downstream of the Site.  The town of Tarpon Springs is located
 approximately 2 miles southeast of the Site.  The Site comprises an area of approximately 130
 acres and includes the former phosphate processing area, elemental phosphorus production
 facilities, and office/administrative buildings.  While operating, the plant utilized a system of
 seventeen waste ponds on-Site. Currently, these unlined ponds contain waste and no water.
 Land use in the  surrounding area includes light industrial, commercial, and residential.  Also, there
 are some undeveloped areas near the Site. The Site is generally flat with an average elevation of
 10 ft above sea level.

 The most significant surface water bodies near the Tarpon Springs Site are the Anclote River
 which is located along the Site's southern and western boundaries and the Gulf of Mexico which is
 approximately 2 miles from the Site. Pinelias County and the Site are underlain by two primary
 aquifers, the surficial aquifer and the Floridan aquifer. The depth to the surficial aquifer
 groundwater is relatively shallow.  The thin nature of the surficial aquifer limits its usefulness as a
 drinking water supply; however, the aquifer provides water for irrigation  purposes. The surficial
 aquifer is separated from the Floridan aquifer by a semi-confining, relatively continuous bed of
 clay to sandy clay. The Floridan aquifer, consisting of a thick sequence of carbonate (limestone)
 rocks which are  hydraulically connected, provides most of the public water supply for Pinellas
 County. There are no active residential, or commercial wells either on-Site or between the Site
 and the Anclote  River; therefore, there are no groundwater users on-Site  or downgradient of the
 Site.
2.0    SITE HISTORY AND ENFORCEMENT ACTIVITIES

 The Stauffer Chemical Company Tarpon Springs Plant (the "Plant") produced elemental
phosphorus using phosphate ore mined from deposits in Florida. The Plant was originally
constructed and operated by the Victor Chemical Company, which began production in 1947.
Stauffer Chemical Company obtained the Plant from Victor Chemical in 1960 and operated it until
shutdown of operations in 1981. In 1983, the decision was made to decommission and dismantle
the Plant permanently. Most of the Plant's former process buildings have since been dismantled.
In 1987, the Stauffer Management Company (SMC) was formed as a result of a divestiture of the
Stauffer Chemical Company.

In the February 1992 Federal Registry Notice, the Stauffer Chemical/Tarpon Springs Site was
proposed for listing on the National Priorities List (NPL) by the United States Environmental
Protection Agency (U.S. EPA). On July 28, 1992, SMC voluntarily entered into an

                                   Page  1  of   61

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                                                                 5  9      0009
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 SOUIM: U.S.GS. Oiwdrangte. Tarpon Springf. Florid* 1973. mxoravfacd 1B6T
   FIGURE 1-1 GEOGRAPHIC LOCATION MAP, SMC TARPON SPRINGS, FLORIDA
                             Figure 1-1

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                                                                     5   9       00".2
 Administrative Order on Consent (Consent Order) with U.S. EPA Region 4 (EPA), which
 requires the performance of a Remedial Investigation and Feasibility Study (RI/FS). The RI and
 FS final reports were completed and approved in March of 1996.

 Several field investigations by various consultants were conducted at the Site.  These
 investigations began with sampling of on-Site groundwater wells in 1974. Beginning in 1987,
 additional, multi-media investigations were conducted by various parties. To the extent possible,
 the studies were utilized in the Remedial Investigation

 In addition to the RI field activities, a Contamination Assessment (CA) investigation was
 conducted at the Site in 1993. The CA was performed for the Florida Department of
 Environmental Protection (FDEP) in response to reported soil and groundwater contamination in
 the vicinity of two former above ground fuel oil storage tanks removed in August 1992. The
 cleanup of these areas in a coordinated approach with this operable unit will  proceed under the
 State of Florida's Underground Storage Tanks Program.

 Black & Veatch Waste Science and Technology Corporation (BVWST), under contract with
 EPA), prepared the Final Baseline Risk Assessment (dated May 18, 1994) for the Site.  EPA
 issued Addendum I (dated June 10, 1994) to revise the Final Baseline Risk Assessment
 acknowledging the conservative nature of the assumption that all Phosphorus present was
 considered to be the most toxic Phosphorus (Elemental Phosphorus). In response to this
 addendum, additional samples were collected and analyzed by Roy F. Weston Incorporated, the
 SMC's consultant in September of 1996. The purpose of this sampling event was to confirm
 presence or absence of Elemental Phosphorus in Site media.  EPA was present to oversee this
 sampling event.  Based on the results of the Phosphorus Sampling Program conducted by
 WESTON, EPA issued Addendum II - Elemental Phosphorus and Diesel (February 2,  1996).
 Also, EPA presented Addendum IIA - Elemental Phosphorus in Surface Water and Sediment on
 February 22, 1995.  Based on the confirmed absence or presence of Elemental Phosphorus in
 discrete samples collect in each Site media, the risk assessment was revised to re-evaluated risk
 levels in Site media. As a result of this additional work, the Final Revised Baseline Risk
 Assessment was issued by EPA on July 21, 1995.

The Feasibility Study (FS) was prepared by WESTON in accordance with the Consent Order.
EPA reviewed and approved this FS. As part of the FS, an assessment of the environmental
impact created by the Site was performed through a comparison of the concentration of
contaminants at the Site with federal and state Applicable or Relevant and Appropriate
Requirements (ARARs) and Site-specific criteria developed in the Baseline Risk Assessment.
                                  Page 5 of  61

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                                                                       5   9       0013
 3.0    HIGHLIGHTS OF COMMUNITY PARTICIPATION
 All basic requirements for public participation under CERCLA Sections 113(k)(2)(B)(I-V) and
 117 were met in the remedy selection process.  The first fact sheet on the Site was distributed in
 February 1993.  Since that time, a community relations plan was developed and implemented at
 the Site. An information repository was established in March  1993, at the Craig Park Branch of
 the Pinellas County Public Library, Spring Street, Tarpon Springs, Florida. The Remedial
 Investigation (December 1993), the Revised Final Baseline Risk Assessment (July 1995),
 Feasibility Study (January 1996) and the Proposed Plan (March 1996) were released to the public
 and continue to be available for public review.  These documents have been incorporated in the
 Administrative Record for the Site.  A copy of the Administrative Record, upon which the remedy
 is based, is available to the public at the information repository. In addition, the Administrative
 Record and the Site files are available for review at the EPA Region 4 offices in Atlanta, Georgia.
 Notices of the availability of these documents were published in the Tampa Tribune and the St.
 Petersburg Times on May 26, 27, and 29 of 1996.

 On May 29, 1996, EPA presented its preferred remedy for the Stauffer Chemical Tarpon Springs
 Superfund  Site during a public meeting at the Gulfside Elementary School, Holiday, Florida. At
 this meeting, representatives of EPA answered questions about the sampling at the Site and the
 remedial alternatives under consideration.

 A 90-day public comment period was held from May 29, 1996, through August 29. 1996. At the
 request of the public, this comment period was extended for an additional 30 days. The public
 comment period concluded on September 30, 1996. EPA's response to comments which were
 received during the comment period are contained in Appendix A of the Record of Decision.
 4.0    SCOPE AND ROLE OF ACTION

 The ROD selects the remedy for the first of two operable units.  This ROD addresses the cleanup
 of heavy metals and radiation in soil and waste at the Site.  Contaminants pose a risk to human
 health and to environmental receptors. The purpose of this proposed action is to prevent current
 or future exposure to contamination and to control the source of contamination. Groundwater
 will be addressed in a subsequent operable unit.
5.0    SUMMARY OF SITE CHARACTERISTICS

5.1    Physiography and Topography

The terrain at and surrounding the Site is generally flat with an average elevation of 10 feet above
sea level. There is a slight slope to the south toward the Anclote River.  The Site is sparsely
wooded in the north and northeastern areas, but is clear of vegetation throughout the main Plant
area. The Site is located in the Gulf Coastal Lowlands physiographic region within the Gulf and

                                   Page 6  of   61

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                                                                          5  9       0014
 Atlantic Coastal Plain physiographic province. The Gulf Coastal Lowlands generally contain
 numerous wetlands which are interspersed with pine-palmetto flatwoods.
 5.2    Geology

 The Site is located in the Gulf Coastal Lowlands Physiographic Province. The Gulf Coastal
 Lowlands are characterized by three sedimentary sequences: (1) unconsolidated fine sand with
 interbeds of clay and marl; (2) fossilferous limestone and dolomite; and (3) gypsiferous limestone
 and dolomite.  The primary sedimentary units underlying Pinellas County comprise a thick,
 continuous sequence of shallow-water platform carbonate rocks ranging in thickness from 10,000
 to 12,000  feet.

 The carbonate rocks underlying Pinellas County form a peninsula which separates Tampa Bay
 from the Gulf of Mexico.  These rocks lie on the southwest flank of the Peninsula Arch. The
 Peninsular Arch is the dominant subsurface structure in southwest Florida whose axis trends in a
 northwest  direction.  In northern Pinellas County, these highly fractured units demonstrate a
 preferred fracture orientation of N 54° W to N 35° W.

 Two distinct stratigraphic units exposed in Pinellas County: A thin veneer of fine sand with clay.
 marl, and phosphorite interbeds (surficial sand) and a thicker, highly variable calcareous sand to
 sandy clay with black phosphate nodules and chert (Hawthorn Formation).  The Pleistocene
 surficial sand is located throughout the county except for in the south-central region. These
 deposits range  in thickness from 5 to 50 feet and rest unconformably upon the underlying Tampa
 formation.  The late Miocene Hawthorn formation is exposed in the south-central region and
 attains thicknesses of approximately 50 to 90 feet.

 A thick sequence of carbonate strata unconformably underlies the surficial sediment. These strata
 are listed in descending order from youngest to oldest: the early Miocene Tampa formation - a
 poorly to semi-cemented, sandy limestone which thickens from 100 feet in the  north to 250 feet in
 the south, the Suwanee formation; a white, fossiliferous, sandy limestone attains a maximum
 thickness of approximately 180 feet, and a series of Eocene limestones and dolomites which may
 achieve thicknesses of 3,000 feet including the Ocala formation - a fossiliferous, chalky limestone
 unit exhibiting some dolomitization;  Avon Park formation - a limestone and dolomite unit
 containing intergranular evaporates;  and the Lake City and Oldsmar formations - a chalky
 limestone with intergranular gypsum and anhydrite deposits.
5.3    Hvdrogeology

Pinellas County is underlain by two primary aquifers, the surficial aquifer, and the Floridan
aquifer. The surficial aquifer is a thin veneer of predominantly fine sand whose pore waters are
influenced by atmospheric pressures. The water table rises and falls within the surficial aquifer in
response to infiltration via precipitation, tidal changes, and variations in atmospheric pressures.

                                    Page 7  of   61

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                                                                        5   9       0015


  In eastern Pinellas, the depth to groundwater is relatively shallow and the saturated thicknesses
  range from 5 to 35 feet while averaging 15 feet. The thin nature of the surficial aquifer limits its
  usefulness as a drinking water supply; however, the aquifer adequately provides water for
  irrigation purposes. Hydrogeologists have measured mean horizontal conductivity (Kh), vertical
  conductivity (Kv), and storativity (S) values of 23 ft/day, 9 ft/day, and 0.3, respectively, for the
  surficial aquifer.

  Underlying the surficial aquifer is a semi-confining, relatively continuous bed of clay to sandy clay.
  The clay unit behaves as a semi-confining unit separating the surficial aquifer from the Floridan
  Aquifer.  Laboratory measurements indicate the vertical hydraulic conductivity of the clay ranges
  from 2.9 x 10^ to 5.6 x 10° ft/day (1.0 x 10'7 to 2 x 10* cm/sec) with an average of 2.3 x 10°
  ft/day (8.1 x 10'7 cm/sec).  In south-central Pinellas, the calcareous sand and sandy clay of the
  Hawthorn formation overlie the Floridan aquifer creating semi-confined to confined aquifer
  conditions.

 The Floridan aquifer consists of a thick sequence of carbonate rocks which are hydraulically
 connected.  The aquifer system is heterogeneous and groundwater flow is principally through a
 series of interconnected fractures and solution channels.  A considerable amount of water is
 stored, and to a lesser degree transmitted, through the pore matrix of limestone units.
 Groundwater flow in the upper Floridan aquifer typically occurs under leaky-confined to confined
 conditions.  In Pinellas County, the Floridan aquifer system encompasses the limestone units of
 the Tampa, Suwannee, Ocala, and Avon Park formations.

 Locally, the top of the aquifer system is defined  as the first competent sequence of limestone
 containing small percentages of clay, marl, and sand.  This lithologic distinction coincides with the
 highly porous Tampa limestone.  Conversely, the base of the aquifer is generally considered to
 occur at the first limestone or dolomite unit containing thin, continuous beds of gypsum. Locally,
 the base of the aquifer occurs at the formational contact separating the Avon Park and Lake City
 limestones.

 Groundwater flow through the Floridan aquifer is by the way of a series of permeable units which
 typically do not coincide with formational boundaries. These permeable units consist of
 interconnected fractures and solution channels which are partly separated  by dense carbonate
 beds containing clay seams of lower permeability. These less permeable units behave as
 semiconfining beds.  Hydrogeologists have subdivided the Floridan aquifer into four
 hydrostratigraphic units separated by three semiconfining units. The shallowest of these
 hydrostratigraphic units are located approximately 10 to 140 feet below MSL (Tampa limestone)
 and approximately 250 to 330 feet below MSL (Suwannee limestone).  Most production wells
 providing public water supply for Pinellas County are open exclusively to the upper
 hydrostratigraphic units. Aquifer tests performed on this  unit yielded an average hydraulic
 conductivity value of 145 ft/day (5.1  x 10'2 cm/sec) and a storativity value of 7.7 x 10"4. The
 deeper hydrostratigraphic units are predominantly saline within the study area and, thus, not
considered important water sources.
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                                                                      5   9       0016
 The average annual water budget for Pinellas County consists of 53 inches of precipitation of
 which 39 inches (74%) is attributed to Evapotranspiration, 6 inches (11%) is attributed to surface
 water runoff, 6 inches as (11%) is attributed to ground water recharge and 2 inches (4%) is
 attributed to leakage to the Floridan Aquifer. Predicted groundwater recharge rates in Pinellas
 County vary from 6 to 11 in/yr.
 5.4    Surface Water and Drainage

  Florida has created several water management districts.  The individual districts have the
 regulatory responsibility for the management, retrieval and storage of any surface water and
 groundwater within the established boundaries.  Pinellas County is located within the
 Southwestern Florida Water Management District (SWFWMD).

 The most significant surface water features near the Tarpon Springs Site are the Anclote River, a
 recreational, Fish and Wildlife Class Ill-marine surface water body, located on the southern Site
 boundary and the Gulf of Mexico, located approximately two miles west of the Site. Class Ill-
 marine surface waters are defined as suitable for fishing and swimming. The Anclote River
 extends from south-central Pasco County, south into Pinellas County and then westward to the
 Gulf of Mexico. The Pinellas County Aquatic Preserve is approximately one mile downstream of
 the Site along this river. Upstream from the Site are the Port of Tarpon sewage treatment Plant,
 and the City of Tarpon Springs. Tidal movement can reverse river flow. The primary uses of this
 river include recreation and maintenance and propagation of wildlife. Stormwater runoff from the
 Site drains directly into the Anclote River.
5.5    Soil

According to the soil survey of Pinellas County, Florida (USDA-SCS, 1972), the primary soil
underlying the Tarpon Springs area are of the Ashtabula St. Lucie Association.  The deep sandy
soil are relatively flat-lying and classified as extremely well drained. There are lesser percentages
of Astar association consisting of poorly drained sandy soil overlain by organic-rich material, and
the Ashtabbula-Adamsville Association, consisting of gently sloping, deep sandy soil. The study
area is underlain predominately by Made Land soil (Ma) which consist of mixed sand, clay, hard
rock, shells and shell fragments.  The thickness of the Made Land soil typically ranges from 2 to 8
feet below ground surface. Adjacent to the Made Land Series to the north and east of the  Site lie
the Ashtabula (AfB) soil consisting of excessively drained, fine sands. Ashtabula soil (AfB) series
predominantly underlies the Made Land soil throughout the Site.
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                                                                        5   9       0017
  5.6    Summary of Site Contaminants

         5.6.1   Substances Detected in Soil

  Soil samples were collected at many different times during the Site investigation process. Initially,
  soil samples were collected by NUS (a company under contract with EPA to conduct the Site
  Inspection) for purposes of ranking the Site and placing it on the National Priorities List.. For the
  Expanded Site Investigation Report in 1989, four surface soil samples and twenty-two subsurface
  soil samples were collected and analyzed.  Concurrent with sampling conducted by EPA, SMC
  utilized the services of Roy F. Weston to sample surface soil. AJso in  1990, Weston collected 47
  discrete samples of the surface soil and 47 samples of the subsurface soil. In addition to Weston's
  discrete soil samples, eight composite surface soil samples were collected in the northeast part of
  the Site.  In 1990 Weston also collected an additional 35 subsurface samples. All of this
  information was compiled into the Past Work Document which has become Volume II of the
  Final Remedial Investigation Report.  Pond material was analyzed to determine the maximum
  degree of contamination. Seventeen samples were collected by Weston in the pond areas on-Site.

  The purpose of the Final Remedial Investigation Report (RI) was to confirm the past work and to
  further define the extent  of contamination at the Site.  As pan of the RI, twenty-one surface and
  seven subsurface soil samples were collected to confirm the past work performed on-Site. The
  analytical results were consistent with the results from earlier sampling work.

         Subsurface Soil

  All subsurface soil samples (collected in  1993) were analyzed for Target Analyte List (TAL)
  metals, cyanide, fluoride, and total phosphorus.  In addition to these parameters, two samples
  were analyzed for Target Compound List (TCL) volatiles, semi-volatiles, pesticides, and PCBs.
  Radiological parameters were also tested.

  Few TCL contaminants were detected in the subsurface soil sample locations. The only two TCL
  volatiles detected were acetone and methylene chloride.  The only TCL semi-volatile was di-n-
  butyl phthalate. No TCL pesticides or PCBs were detected.

  Arsenic, lead, fluoride, and total phospK5rt»-were detected in the subsurface soil.

  The radiological parameters of Gross Alpha, Gross Beta, Radium-226,  Radon-222, and
  Polonium-210 were ail detected in on-Site subsurface soil.

For more detailed information concerning the subsurface soil results please refer to the Final
Remedial Investigation.

       Surface Soil

As part of the RI, twenty-two discrete samples were collected in the main production area,

                                  Page 10  of  61

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                                                                            5  9       0018

  northeast property, and southern properly areas.  In 1993, three discrete samples were collected at
  the Gulfside Elementary School located directly across the street from the Site on Anclote
  Boulevard. Ten additional surface soil samples were collected at the elementary school in
  February 1996.  See Table 5-1 for further detail.

  All samples on the elementary school property were detected at normal levels.

  Surface soil samples were tested for one or more of the following: TAL metals, Cyanide, Fluoride.
  Total Phosphorus, Elemental Phosphorus, TCL volatiles. semi\ olatiles, pesticides. Gross Alpha
  Radiation, Gross Beta Radiation, and Gross Gamma Radiation. Specifically for the radiological
 parameters, an isotopic analysis was performed which confirmed that the radiological
 contamination is detected in the form of Radium 226.

 Soil within the Site is contaminated  with radionuclides primarily found in the uranium decay chain,
 specifically Radium 226. As noted earlier, radioactive waste material, suspected to have originated
 from the Phosphate ore (radium) processing Plant, were disposed on-Site.  The radioactive decay
 of Radium 226 in soil causes elevated concentrations of radon gas and radon decay products.

 In broad terms, the results of the assessment for surface soil were as follows:

        •      The main contaminants of concern for soil were radiological constituents, mostly
               located in the former slag processing area, railroads, road, and parking lots. In
               addition, some chemical contaminants including arsenic, antimony, beryllium,
               cadmium, chromium, thallium, PAHs, and fluoride, were identified. For a complete
               list of Potential Contaminants of Concern refer to Table 6-1.

        •      The pond material were not evaluated from a risk standpoint in the Final Baseline
               Risk Assessment (BVWST, 1994).  The risk assessment assumed that this material
              would be treated or remediated. Radiological levels detected in the ponds exceeded
              residential and commercial use standards. Refer to Table 6-1  Potential
              Contaminants of Concern for a complete list of contaminants.
Contaminant detection tables for all media are presented as Table 5-1, 5-2, 5-3, and 5-4.  These
tables present the sampling results from the Remedial Investigation for the media of soil and pond
material.

       5.6.2  Substances Detected in Surface Water and Sediment

Surface water and sediment samples were collected from the Anclote River directly adjacent to the
Site (located directly south and south-west of the Site property boundary). Surface water and
sediment samples were collected in a two phase sampling event.  The first phase focused on the
comprehensive sampling of the Anclote River's surface water and sediment. The sample locations

                                   Page  11  of   61

-------
                                                                       5   9       00", 9

 were selected to include areas upstream, areas downstream, and areas adjacent to the Site.  The
 second phase of sample collection included a focused investigation of the sediment in the Myers
 Cove area adjacent to the Site. During the RI, a total of 15 surface water and 27 sediment samples
 were collected. Refer to Table 5-1, 5-2, and 5-3.

 The results of the RI sampling documented that Site-related contamination was not detected in
 surface water above background (normal) levels.  Only mercury and cadmium were detected (once
 each) above the National Oceanic and Atmospheric Administration (NOAA) Effect Range-Low
 (ER-L) guideline values, at sediment locations in Meyers Cove.  Both contaminants did not exceed
 the NOAA Effects Range-Medium (ER-M) guideline values. For further detail, refer to the Final
 Remedial Investigation Report (WESTON 1993).
       5.6.3   Air Monitoring

 Air monitoring results obtained during the RI field work indicated that airborne volatile organics
 compounds were not problematic at the Site unless construction activities are in progress.  Prior to
 excavation, drilling, and sampling activities, on-Site workers tested the air quality with either a
'flame ionizination detector (FID) and/or an organic vapor analyzer (OVA).   Instrument readings
 were taken continuously at each drilling location for monitor wells.  In addition VOCs were not
 detected during air monitoring conducted to support the health and safety plan. Elemental
 Phosphorus is the only contaminant of concern that may present a problem since it may ignite
 spontaneously when exposed to the atmosphere. Supported by historical information and the
 results of the RI field  work, EPA has drawn the conclusion that airborne contaminant transport is
 not a significant migration pathway at the Site. The exceptions to this statement would exist when
the pond and other contaminated areas are excavated or disturbed.  This scenario may cause the
Elemental Phosphorus to be exposed to the atmosphere. During the Removal Action construction
activities on-Site, asbestos was detected at levels below the Occupational Safety and Health
Administration (OSHA) Permissible Exposure Limit.  Even though the asbestos levels are below
the Permissible Exposure Limits, EPA will add asbestos to the list of Contaminants of Concern.
This decision is based on input and concerns expressed by the community. Additional samples will
be collected and analyzed for asbestos as part of the Remedial Design.
                                  Page  12  of   61

-------
                                                                        5   9        0020
SOUKC& SvuMig i-~m**nal Auocattl
AAdMt nnt Wtur Cetumn tnd S«4nMM
Simpling riuJ fepcfl. »S1
/I
SW.7
A
UJ
J.Og
OJO
0.06
•MM^^
6
3.ia
i.«
OJ2
NO
C
l.0»
j.0w
OJ2
0.04
I
     •  Appraoxiol* Sorfoet Wctcr
   I   Aflolyte fraunt in llenk
   NO  NolDtltctatf
   •   NafD*ta0c4{2cport«jVaUb
I4CT-11U IW1*»»
                     MARCH/APRIL 1993 SURFACE WATER ANALYTICAL
                     RESULTS OF SELECTED PARAUETERS
                                   Figure 5-1
                                Page 13 of 57

-------
                                                                5   9
0021
    5CUKC&
           Anctou f+*t< Wuif Column tr.4
           S*drrxm &i/nplin0 FV»«» R«£oi ISM.
                 50-07
                   "  I  C
                  IO.ll9.II
             51.9 I242I2A.O
SD-n
11.70
211.0


50-10
BA9
197.0
                •11
               50-12
               3M
               39.X
                   »T2
                  50-08
                   NO
                   55.2
Legend
 SD-12
 NO
                                          •OITfc
                                       1993 SEDIMENT ANALYTICAL
                         RESULTS OF SELECTED  PARAUETERS
                                  Rgure 5-2
                                 Page i< of 57

-------
                                                              5   9        0022
  A/M2DU Hiowr Sreim.ni Coring
  IV.alRtpeM.1ffX
                                           IU. 17.1
                                           0.1). 0.11
                                           J.f.O.
                                           17.1 3*7
                          Meyer's Cove
                           UC  14B 14A
                                       .^9. 0.63
                                       1.< 1^
                                     O.IOu. 0.12v
Zinc,
nuorid*. mg/Vg
fkeipKoirvi. me/Va
    Sample locelion
       fxl (Report Value it
Oetocfton UmW.
                JULY  1993  SEDIMENT CORE  ANALYTICAL
                RESULTS OF SELECTED PARAMETERS
                         Figure 5-3
                       Page 15 of 57

-------
                                                                                             TAIII.KM
                                                                                   MIKKACK .SOIL XAMI'l-KS
OlltMICAI.
OKCANICS
•ail.OKOPIUiNOI.
j-MirniYiXAi'imiAU-iNi;
2.4-DINITKOTOI.UIiNli
2.4.6-TRJCI II.OKOPIII-NOI.
i MrrriiYiJ-iii-NOt.
ACtiNAI'imiliNi;
ACKNAPimiYU-NIs
ACIiTONB
AU'llA-ClU-OklMNI:
III-N/Q A ANTllKAaiNIJ—
IIKNZO A PYRJiNIC'—
lll-N/0 II H-UORANTHI-NIi— •
III;N/O cjuiPi-RYiitXi;
IH-N/.O K|i i.uoRArrnu:Ni-—
k.-AKIIAZOIj;
aiRYSIsNIi*"*
DI-N-IIII TYI. PIIT1IALATI-:
OUII-N/OFUKAN
DUIIiN/^AJIlANTIIKACIiNIi***
lUJORANTHHNH
l.UOKI-NI:
INDUNOJ LW-CDlPYRIiNli***
LSOPIIORONH
MicriiYiJ-Nii anxjKjni-
NAPlllAIJ'Nfi
l'i:NTAOIII.OROrili;NOI.
I'HHNANTIIKI-Ni;
I'lllsNOI.
PJMMMi
I'.P-ODT
I'YRCNIC
KRWIIKNCY
OKDK'm.TS

1 / 9
2/ 9
I/ «
I/ 9
1 / 9
I/ 9
11 9
I/ It
I/ 12
J/ 9
J/ !>
61 9
61 9
S/ 9
?/ 9
6/ 9
9/ 9
1 / 9
2/9
6/ 9
2/ 9
S/ 9
I/ 9
•I/ II
/ 9
/ 9
/ 9
/ 9
/ 12
/ 12
7/ 9
KANCK
OK DKIKiM.S
|i(^K<;

>0
45 • 60
7KU
990
I3
68 • 4.100
43 • I.6IM)
42 • I.IOO
Ml - 200
5.1 - 2.1 IM»
7H . I..100
3«
100 - JMO
6-1 • I/.OO
75 - 450
KK - I.MXI
540
7 . 25
48 - 4K
2.NU
CONt.-fJVIKAllUN
II«:/K<:

Nl)
Nl>
Nl>
Nl)
Nl)
Nl)
Nl)
Nl)
Nl)
Nl)
Nl)
Nl)
Nl)
Nl)
Nl)
NO
NO
NO
NO
NO
NO
NO
NO
Nl)
NO
NO
NO
Nl)
Nl)
NO
Nl)
KM;ION in
KKSIDKNTIAI. SOU."
H«/K<: ;

19.OOO

940
5».000
19.000
470.000

780.000
490

88



12.000

780.000


J 10.000
J 10.000

670.000
85.000
.110.000
5.JOO

4.700.000
I.90O
1.900
2JO.OOO
rO
CM
O
O
 ON

 uO
                                                                                                                                                                                                 in

                                                                                                                                                                                                 •M
                                                                                                                                                                                                 O
                                                                                                                                                                                                 VD
                                                                                                                                                                                                 H
                                                                                                                                                                                                 0)

                                                                                                                                                                                                 Pi
             •Tliit; Ulile lunnuri/M UK ditmicils Uul wtrc ikUilcJ in al leiM one tanvle i>i lliis nicJnini. HMS Hulial lia of dicniii-il* in further evaluate J by i-a^iarii« to qifv«|iriilc
             naceiiifv; viliic*. aifh is mem liitigroiiml cniKeK/alioiK. iii tirclcr lo niclcil (lie list ofilieinii-aU oT|Mlcicr ConliilciHrc Limil*.

             •• Re/jiwi in vilue» were oWaiied fran Die Khl Mated C«iceistiui  PAIIs tiascil wi eaili ««if NmmN relative |M*cmy In Ute |x4ciHy un>ai/uafkpuuinl KUif tie.

-------
                                                                                  SIWK
                                                                                                I.KM
IQ
 H
 •J

 O
 Hi
 UI
CIIKMICAI.
INORGANICS
AMJMINUM
ANTIMONY
ARSIiNIC
IIAKJUM
III-RYIJJUM
CADMIUM
:ALCIUM
OIKOMIUM
COIIAI.T
COPPI-X
FLUORIOK
IRON
IJ-AI)
MAGNESIUM
MANCJANI3C
MERCURY
NTCKI-J.
POTASSIUM
.SI3J-NIUM
SO.VI-R
SOfNUM
niAIJJtfM
/JNC
KHKOUKNCY
OK DKTKCTS

IH/ 21
»/ 21
IJ/ 21
II / 1)
U/ 21
II / 21
18 / 21
17 / 21
lOt 21
14 / 21
I9/ 21
18 / 21
I7/ 21
17 / 21
IS/ 21
It 21
17 / 21
II / 21
12 / 21
4t 21
17 / 21
8/21
IK/ 21
KANCK
OK DKTKCTS
|iC/KC

287.000 • 6. HI 0.000
4.900 • 32.100
410. 127.000
2.000 . K0.900
160 - 1.600
)90 . J7.400
36.000 - .177.VOO.OOO
1.100 . 161.00(1
1.100 - 33JOO
I.XOO • 65.500
2.400 • 2.810.000
131.000- 44.800.000
1.600. 324.000
39.000- 3.91 0.WH)
.>W . 292.000
230. 420
1.900- II.VOOQ
in i.ooo - i .6x0.000
240- 32.500
1.200. 9.700
8.400 . 15.500.000
370 . 13.400
770 . 519.000
MKAN I>K 1 M.TKD
C:ONt>aVTKATION
|iC/KC

2.765.0)0
14.6X9
26.RH5
29.206
672
14.346
IO9.96K.I67
43.700
• 7J60
20.3KA
401.774
9.097.167
58.691
1.226.994
88.099
325
24.759
708.846
7.828
4.225
2.869.0041
4.110
120.941
MKAN IIACK<;KOUNI>
CONCKNTKATION
pC/KR

631
Nl)
NO
3.2
NO
Nl>
2240
I.J
NO
0.92
NO
455
7.5
70.6
20.A
Nl)
4
Nl>
0.32
Nl>
.15.2
Nl>
J8
KM:ION HI
KK.MOI'^ITIAL. SOIL"
liO/KC

23.000.000
3.100
360
550.000
150
3.900

3 9.000

290.CXNI
470.000
'


.19.000
2..100
I60.OOO

.19.000
.19.000


2..IINI.ODO
            •TINS table xunmarizts the chemicib lhat were ddeilcd in at Icasl one sample in lltis mtilriim. This iniliil list ofdictnirals is fiirllwr evaluated by conf ivjiy; to aji|iro|riale
            xcrceiring vidie*. aufi n mean bacfcpmmj r«MvenlnlioiM. in order to stletl die list of dtcinit-als of|H>4ti(iil cointni dial will l>e evaluated in die ItKA. iri iccorilance widi
            (•PA Region IV guidance, the non-dcleds were not imorporntd k«o UK averigc vaiiceitfraiiorH. llowevtr.mm-iklttls arc *K hided in Hie caliulalioii of 95 (Krcei*
            ttyficr Confidence Until*.
            •• Region n value* were obtained from die RM lined Concentration Table, fourth Qualcr. 1993 (XX^ndcr 15.1993).
            For nonvarcinogcm. the large! IIQ wa* adjusted from 1.0 to 0.1 in accordance wHti I-I'A Region IV giiiilun e.
            ••• The TIT a|«^roarh will be wed to evahiate risk from rarchmgcnif PAIIx based on cadi cwnHnuNts relative |xi»tiicy In Hie (xrtcm-y orbcn/n(a)|>yreiM;.
            Siwe die maximum conrenlration of lxiuo(a)pyrenc exceeds its Region III screciing value, all delected circimigeiiif PAIK will be retained ax
            COPC* in aurface toil.
            .Sample SS93-2 wa* used •< die background sanf tic.
VO
                                                                                                                                                                                                  CD
                                                                                                                                                                                                  CD
                                                                                                                                                                                                  hO

-------
                                                                                                       TAIII.K 5-2
                                                                                                .SKDIMKNI XA.MVl.KS
C1IKMICAL
INOKCANICS
ALUMINUM
ARSI-NIC
DARniM
lU-RYIJJUM
CADMIUM
CALCIUM
CHROMIUM
COPPER
FLUORIDE
IRON
LEAD
MAONIuSIUM
MANOANRSli
MI-ROIRY
NICKH.
PHOSPHORUS
POTASSIUM
SI-U-NIUM
SODIUM
ZINC
OKCANICS
AcirroNii
IttmianrYIJIIiXYDrimiALATK
MI-THYU-Ni; CIILORIDIi
pitNTACiiijOROpm-NOL
pin-Noi.
PYRKNii
TOI.UP.NU
KRKOIIKNCY
OK DETECTION

12 / 27
12 / 2?
12 / 27
J / 27
2 / 27
12 / 27
12 / 27
II / 27
2« / 27
12 / 27
12 / 27
12 / 27
12 / 27
) / 27
2 / 27
27 / 27
II / 27
2 / 27
12 / 27
12 / 27

1 / 2
1 / 2
1 / 2
1 / 2
2/2
. 1/2
. 2/2
KANCK
OK MK.mrrs
nC/KR

358.000 . 4.2VO.O(K)
•470 - ).400
900 • 6JOO
260 . 290
950 . 1.400
1. (150.000 . 29.000.0OO
1.700 . 15.400
3.200 . 20.900
J.I 00 . 44.300
370.000 • 4.340.000
1.400 • 16.400
357.000 - 2,310.000
1.400 . 19.4011
98 • 5X0
5.900 - 5.900
.17.200 - 2.560.000
204.000 - 828.000
260 . 420
1.740.000 . 9.780.0OO
4.KOO • 32.100

15
260
4
100
M • AR
6K.000
51 - 62
MK.AN OKTK.CI Kl>
rONC.'KNI RATION
|iC/K<:

1.954.750
1.763
3.330
277
1.175
11.295.833
7.325
9.025
12.872
2.105.667
6.025
1.280.167
R.I 50
286
5.900
639.993
493.364
340
5.300.000
15.300

15
260
4
KM)
67
68.000
57
MKAN IIA<:K<:KOIINI>
CONCKNTKATION
fic/K<:

Nl)
Nl>
Nl)
Nl)
NO
ND
Nl)
NO
.1
Nl)
ND
Nl)
Nl)
Nl)
ND
117
Nl)
Nl)
NO
Nl)

Nl>
44
2
Nl)
Nl>
Nl>
32
KKKION III
RKSIDKNTIAI.SOII.**
pOKO

23.000.000
360
550.000
150
3.900

39.000
290.000
470.000



39.000
2..100
160.000


39.000

2.300.000

7KU.OOO
46.001)
R.VOOO
5.100
4.700.000
230.000
1.600. 000
•tf
p»
U)
H
OB
 in
 •4
        •This ItMc «mmriKS (he chanictli Hat wtre dcfcdcd in U lci<4 one snnfile in Otis medium. TIHs Mulial list ofthctnicils is HirOier cvahiiletl by confiviilRlo ip|irofvialc
        tcrcaiinit vjhiei. wch is mem background conrcitfnlians. in order lo select Uie list ofclicmiHls of |K>crcct«
        lljijKT ConTioVncc Unrtt.
        •* Repon 10 v.Iucs were oUiined from Che Risk IU«d Concertnlion TiMe. l-.mrHi Quuier. 199.1 (er 15.1993).
        For noncircinogcm. Iht target IIQ wis idjusleJ from 1.0 to 0.1 in accordance wrtJi lil'A Region IV pii Ja
                    I. SD-2. and SO-) wtre utcd H btdcerand xamjiles.
cn

VO
                                                                                                                                                                                             O
                                                                                                                                                                                             O

-------
                                                                                 TAJfl!Ts-J
                                                                       NUUKACt: \VA I KM .NAIMM.KS
CM
CD
CD


OS

LO








CIIKMICAL
INOKCANH:
ALUMINUM
AR-SliNIC
IIAK1IIM
CAIX1UM
COPPFJI
II.UORJDI;
IKON
IJ-AD
MAtiNI-SIIJM
MIIKCIIKY
I'llOSPMOKUS
I-OTASSHIM
SI-U-NHJM
SODIUM
TtlAUJIIM
OMCANIC
ACIiTONK
TOMII-N1-
KHKOUKNCY
OK I>K TM.TION

15 / 15
« / 15
15 / 15
15 / 15
II / 15
15 / 15
15 / 15
6/15
15 / 15
II / 15
4 / 15
15 / IS
1 / 15
15 / 15
1 / 15

1 / 2
1 / 2
KANCK
ot DKIKCI.S
i.<:/i.

ji - m
1 - 6
6-11
206.IKX) . 1IK.OOO
.1 - 15
0 IV . 1
17 . 1.15
1 . )
72J.OOO . I..IOO.WW
O.I) - 1
0.05 • 0.06
31 1.CIKI>
CON< KNIKAIION
|i(^l.

5)
I
11
J.IS.WJ
9
0.51
6.1
2
914.601)
O.J!>
0.06
J79.A.11
7
K.Otll.t.t.t
17

24
«>
MKAN IIA< kCKOIJNI)
«)N( KNIKATION
Itl'Jl.

9*
2
»
I24.KOU
1.1
0.42
I6»
.1
JJ0.667
0.27
0.09
152.067
2J
4.260.000
19

15
4*
Awgc ••
ttCJt.
.

0.14

"





0.15




6


2OH.OOO
• Itii* table tuniiuri/cv Uic dwnicih Uul wne dtlcclcd in M lead one saiiftlc iii itiis mtawun. lltis iiiilul li\l of tlmiiii»ls is liiillicr c\-aNiaicd by con^iirii« la
MTcaiiiv; vilucii. Mill •< niciii bitipuwnl ium-a«nlhiitk n milcr lo itcltil ilic litt of iliciiiiuls ul'|H4ciiililx<'>ilcfii (ii|xljlcil t)uttittfi. 1992).
The v»be* titled re|«cvci« lumau health. fumuni|i«i«i of organism iwainclcrti.

Sample* SW-I. SW-2. tnd SW-J wa e used IK bwkpound «»n J«».
                                                                                             Page 19 of 57

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                                5  9     0027
                       TABLE S 4
                 POND MATERUtSAMPI.es
CHEMICAL
INORGANICS
ALUMINUM
ANTIMONY
ARSENIC
BARIUM
BERYLLIUM
CADMIUM
CALCIUM
CHROMIUM
COBALT
COWER
FLUORIDE
IRON
W>
'.GNESIUM
MANGANESE
MERCURY
NICKEL
ELEMENTAL PHOSPHORUS
POTASSIUM
SELENIUM
SILVER
SODIUM
THALLIUM
ZINC
FREQUENCY
ororrccnoN

J / }
) / i
3/3
3/3
J / 3
3/3
3 / 3
3 / 3
3/3
3 / 3
3/3
3/3
3/3
3 /
3 /
3 /
3 /
3 /
3 /
3 /
J /
3 /
3/3
3/3
RANGE
OFDCTTCR
|iC/K'C
•
4.510.000 - 6.060.000
27.000 . 33.000
19.800 ' 203.000
46.100 • 1)4.000
710 - 2.000
I3JOO . 36.300
167.000.000 - 370.000.000
30.000 • 226.000
UOO . 4.200
9.900 - 1.040.000
193.000 • 2.230.000
4.290.000 • 9.760.000
126.000 . 900.000
1.030.000 - 3.030.000
38.400 . 113.000
130 • 2.200
9.300 . 14.000
2l.lOO.ono . 69.iuo.ooo
933.000 - 4.820.000
6.600 . 33.100
4.500 • 19.300
2.I70.IKX) • I4.IOO.OUU
6.90V • 36.200
297.000 - 7)8.000
MEANDLTCCTCD
CONCr/ORATION
liG/KC

3.130.000
43.467
83.300
74.133
1.237
28.800
274.666.667
104.800
2.833
376.867
1.41 8 J33
7.116.667
386.000
2.630.000
80.400
887
17.000
42.400.000
2.3 34.333
23.433
11.900
6.463.333
23.933
J4IJ33
HtCIONd
RCSOTEmiALSOIL"
MC/k'G

23.000.UOO
J.I 00
360
550.000
1)0
J.900

39.01)0

2W.OOO
470.000



39.000
2JOO
160.000


39.000
39.000


2.300.0W
Page 20 of  57

-------
                                                                                                              5    9          0028
                                                                                              TAIIl.E S 4
                                                                                     POND MATERIAL SAMPLES
CHEMICAL
ORGANIC*
ACETONE
BENZOfAlAMTHRACENE"*
BENZO(B]FUK)RANnHKNE—
BENZO(O.H.nPERYl£ME
BENZOfKJFLUORANTHENE"*
Bisfj-eHnrtKEXYL)«n«Ai>ni
CHRYSENE*"
DI-N-BUrn. PHIMALATC
KLUORANTHENE
INDENOf 1 .2 J-CDJPYRENE—
MKTIfYLENE CHLORIDE
PHENAXTHRENE
PYRENE
FRCQUCNCV
1 / 1
1 / 1
2 / 1
2 / 1
I / 1
1 / J
2/3
J / 1
1 / 1
2 / J
2/1
I / 1
1 / I
RANGE
110
2.KOO
1 tO • 3.200
91 . 1.300
32 ' I.I 00
2.200
61 . 4.100
110 . 670
1.900
120 - I.SOO
3 . 27
2.000
1.100
MEANDE1TCTCD
110
2.100
2.«IO
797
374
2.200
2.4 11
300
1.900
960
16
2.000
1.JOO
REGION OJ
78U.IXKJ
SR
88

88
46.00(1
88
780.000
J 10.000
l«
v.vooo

2JO.OOO
 *Thi« (*le tunnurun ihc rttenuoli Out wen ddctled in «tn« oot iBiylc in (hit medium. Thii iniliil lid ofihenitilf ii furtha nnluKcd by
 tcrcmiog vihin. writ u mem bKkjround coocentmiom, in ordv lo ictcct (he li« orchanirtli ofpotaliil conccni th* will be cviluMcd iii (hr IIRA In *c(ord vwc with
 EPA Region (V fuidme. (he non-detccti were not incerpomed into the iven(e canccntnlion*. However, oon-drtnti ire included in (he cilculMiun of 9.< pa-cat
 Upper Confidante LimiU

 •• Reyion (D v»!uo wve otxiincd front (he Riik Ducd CoocaKnlioo Trf>ie. FourUi Quvtcr 1991 (October 13.1WJ).
 For noncrtinofOK. (he t»|« IIQ wn »Jju* ed from 1.0 lo 0.1 in accordance with i-TA Region IV jpiid»irc,

 ••• Tlie THF «pciro*di will be uied In evilnne ri* from cvrinoseiitc PAlli bu«d on nch rompoutirfi rrlaivt po«niey lo die p.Wn«y ol'hai/odVfnie
Tlte RefiiM 01 Mrccriiig vtlitr far ImKiXaiiiyreiir it V* ufttft.   All drtecled wcnwymic PAlU will  be reiiincd it COPC. iii Uie pond ntaierial.
                                               Page  21  of    57

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                                                                         5   9      0029
 6.0    SUMMARY OF SITE RISKS

 CERCLA directs EPA to conduct a baseline risk assessment to determine whether a Superfund
 Site poses a current or potential threat to human health and the environment in the absence of any
 remedial action.  The baseline risk assessment provides the basis for determining whether or not
 remedial action is necessary. This risk assessment also provides the justification for performing the
 remedial action. Based upon this analysis, it was determined that the Site does pose a current or
 potential risk.

 Site risks are summarized in the Revised Final Baseline Risk Assessment - Part A and B (B VWST-
 July 21, 1995), which was submitted as part of the Remedial Investigation, consist of three major
 sections: Risk Assessment - Chemical, Risk Assessment - Radiological, and the Baseline
 Ecological Risk Assessment. Chemical risks and radiological risks are discussed separately due to
 the complex nature of contamination at this Site. Following the discussion of each risk category,
 the risks posed by the aggregate categories will be summarized.

 The major risks currently associated with the Site are inhalation, ingestion, and dermal contact
 with contaminated soil and slag. Actual or threatened releases of hazardous substances from the
 Site, if not addressed may present an imminent and substantial endangerment to human health,
 welfare, or the environment.
6.1    Risk Assessment Overview - Chemical

The chemical health threat at the Site is from heavy metal contamination.  The major chemicals of
concern are arsenic which is a known carcinogen and elemental phosphorus which is reactive when
exposed to the air.  See Table 6-1 for the list of Contaminants of Concern for the Stauffer
Chemical/Tarpon Springs Site. Based on additional sampling results, and comments on the
proposed plan asbestos and arsenic have been added to the list.

EPA Region 4 does not consider direct exposure to subsurface soil to be a standard scenario that
should be evaluated in the baseline risk assessment for protection of human health and the
environment. Therefore, chemicals of potential concern were not selected for subsurface soil;
however, this medium will be evaluated for the protection of groundwater.
                                  Page  22  of   61

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                                              5  9     0030
Table 6-1 Summary of Potential Contaminants of Concern
j CHEMICAL
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
1 Cobalt
Copper
Fluoride
Lead
Manganese
Mercury
Nickel
Elemental Phosphorus
Selenium
Thallium
Zinc
2-MethyInaphthalene
Acenaphthylene
Acetone
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Chrysene
Dibenzofuran
| Dibenz(a,h)anthracene
1 Indeno(l,2,3-cd)pyrene
| Phenanthrene
SOIL

X
X

X
X
X
X

X
X
X
X

X

X

X
X

X
X
X
X
X
X
X
X
X
X
SURFACE
WATER


X
X








X







X










SEDIMENT


X

X





X




















POND MATERIAL

X
X

X
X
X
X
X
X
X
X
X

X

X




X

X
X
X
X


X
X
             Page 23  of  61

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                                                                           5  9       0031
 6.2    Human Health Risk
        6.2.1   Chemical

 The Baseline Risk Assessment characterized potential current and future risks to human health and
 the environment from exposure to chemicals found on-Site.

 The conceptual Site model for the Stauffer Chemical Site incorporates information on the potential
 chemical sources, affected media, release mechanisms, routes of migration, and known or potential
 human receptors. The purpose of the conceptual Site model is to provide a framework with which
 to identify potential exposure pathways occurring at the Site.  Information presented in the RI,
 local land and water uses, and potential receptors was used to identify potential exposure pathways
 at the Site.

 An exposure pathway consists of four elements: 1) a source and mechanism of chemical release; 2)
 a retention or transport medium (or media in cases involving media transfer of chemicals); 3) a
 point of potential human contact with the contaminated medium; and 4) an exposure route (i.e.,
 ingestion) at the contact point. When all of these elements are present, the pathway is considered
 complete.  The assessment of pathways by which human receptors may be exposed to
 contaminants includes an examination of existing migration pathways (i.e., soil and air) and
 exposure routes (i.e., inhalation ingestion, and dermal absorption), as well as those that may be
 reasonably expected in the future.

 After the sources of contaminants are identified, the next step in the development of the conceptual
 model is to determine mechanisms of release to environmental media.  The primary release
 mechanisms are infiltration, runoff, and tidal action from the disposal ponds, and spills leaching
 from the former Plant operating equipment.  The secondary source of chemicals is surface and
 subsurface soil.  Secondary release mechanisms include infiltration and surface runoff.

 Contaminated groundwater and surface soil are believed to be the major sources of potential
 exposure for human receptors, followed by surface water, sediment, and air. The following
 paragraphs describe the pathways by which human receptors can be exposed to contaminated
 media.

 Surface soil samples were collected from the main production, northeast property, and southeast
 property areas of the Site.  A current or future maintenance worker may be exposed to
 contaminants in surface soil. Another potential future use may involve developing the Site for
 residential use.  Therefore, a future resident will be evaluated for exposure to on-Site surface soil.
For more detail please refer to the Final Revised Baseline Risk Assessment.
                                   Page  24  of  61

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                                                                             5   9       0032
 Surface water and sediment samples were collected at several locations along the Anclote River.
 A current or future resident may occasionally be exposed to surface water and sediment.  Nearby
 residents or future on-Site residents may be exposed to chemicals in surface water and sediment
 via two exposure routes - fishing and/or swimming (or wading) in the Anclote River.
        6.2.2   Radiological Overview and Assumptions

 Since phosphate ore contains naturally occurring radioactive material (NORM), the slag material
 has appreciable amounts of measurable radioactivity which has been technically enhanced.  The
 phosphate ore production activity apparently concentrated the radiation in the slag and disposed of
 the slag in the processing area of the Site.  The Baseline Risk Assessment identified the major
 potential risks associated with the NORM components of the slag material.

 The identification of potential pathways for radiological risk analysis is similar to that used for
 chemical risk analysis.  However, several major differences do exist and need to be considered.
 First, radionuclide intake through the skin is a minimal pathway and need not be analyzed (i.e.,
 dermal contact will not be a considered pathway). Second, the presence of Ra-226 in the soil at
 the Site indicates that Rn-222 emanation will occur and provide a potential pathway.  Third, the
 NORM radioactivity in the soil from the processing produces an ambient radiation field that
 exceeds background levels.

 The following assumptions were made to assess the major pathways of exposure.

 1.     Consistent with the risk analysis performed for the chemical hazards on the Tarpon  Springs
       Site, the potential receptors are designated as listed below:
              a.  On-Site Worker (current and future)
              b.  Off-Site Adult Resident (current)
              c.  Off-Site Child Resident (current)
              d.  On-Site Adult Resident (future)
              e.  On-Site Child Resident (future)

2.     Some monitoring results identify the presence of the nuclides K-40 and Cs-137 in relatively
       small concentrations. These nuclides were not considered as part of this analysis. Cs-137
       is a fission product that is found worldwide in environmental samples. Processing at the
       Tarpon Springs Site should not have enhanced the concentration of this isotope to
       significant levels greater than those found elsewhere in Florida.  K-40 is a naturally
       occurring radioisotope that is part of elemental potassium.  Its presence in concentrations
       above normal (background) are of negligible radiological concern because the amount of
       potassium in the human body at any given time is under control (i.e., the body regulates
       how much K-40 is present in tissues at any time).
                                   Page  25 of   61

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                                                                            5   9       0033
 3.     To the extent possible, parameters were used to be consistent with the chemical risk
        analysis. This includes water consumption rate, exposure fractions, exposure durations,
        and soil/sediment ingestion rates. Alternate parameters from recognized standards were
        used in specific pathways as needed and are described in the discussion of each model.

 4.     Because the radiological data from the various sources are in relative agreement with each
        other (i.e., the mean and average do not vary by orders of magnitude), the maximum
        reported concentration for an environmental sample will be utilized in all calculations. This
        approach provides a bounding value for the risk associated with the pathways.

 5.     Consistent with the discussion presented for the chemical risk analysis, fugitive dust is not
        considered to be a pathway for exposure.

 6.     Consistent with the discussion presented for the chemical risk analysis (B&V 1994), off-
        Site drinking water is solely from the local city water supply.  Therefore, no current
        ingestion of groundwater is assumed to take place. However, an analysis is performed for
        future on-Site residents who may use wells on the Tarpon Springs Site for drinking water
        purposes.

 7.     Consistent with the discussion presented for chemical risk analysis, current off-Site child
        residents are assumed not to be exposed to sediment.

 8.     No isotopic data were present for surface water; therefore, scenarios using surface water
        were not analyzed.

 9.     For purposes of analysis of soil data, the activity of Ac-227 is assumed to be equal to that
        of Th-227, since these would most likely be in secular equilibrium. Similarly, the activity of
        Pb-210 is assumed to be equal  to that ofRa-226, and the activity of Th-228 is assumed to
        be equal to that of Pb-212.  These assumptions are necessary because published risk factors
        do not include long-lived progeny.  Therefore, it is necessary to consider the activities of
        parent isotope and long-lived progeny separately with regard to activity and risk.

 10.     Risk values are taken from "Health Effects Assessment Summary Tables (FY1992)" (EPA
        1992) except as noted for the scenario involving irradiation by roadbed material.
6.3    Summary of Exposure Scenarios

This section discusses the rationale for selection of exposure pathways and routes of concern for
both the current and future exposure scenarios.

Table 6-2 and 6-3 represent the carcinogenic and non-carcinogenic risk posed by chemical
contaminants of concern for significant pathways. Table 6-4 represent a comparison of the
maximum detection concentration of lead and the EPA Interim Soil cleanup level for residential

                                   Page  26 of   61

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                                                                         5   9       OC34
  soil.

        6.3.1   Summary of the Chemical Exposure Scenarios

        Current/Future Maintenance Worker

  On-Site maintenance workers were assumed to be exposed to Site-related contaminants in surface
  soil or fugitive dust emissions during landscaping, mowing, or other outdoor activities.  The routes
  of exposure considered for the on-Site maintenance worker were incidental ingestion and dermal
  contact with contaminants in surface soil and inhalation of fugitive dust. It was assumed that if the
  Site remains commercial/industrial in the future, a maintenance worker would still have the
 greatest potential for exposure to Site contaminants.  Therefore, the future worker scenario is the
 same as the current worker scenario.

 The air pathway was qualitatively evaluated as an exposure pathway for paniculate emissions from
 surface soil.  With the exception of the slag processing area, the majority of the Site is either
 vegetated or covered by impervious material. Inorganic chemicals present in surface soil in the
 slag processing area may adsorb to soil particles which could then potentially be transported via
 wind erosion. Although surface soil in the slag processing area are relatively homogeneous, the
 surface is not elevated and the soil is compact.

 The closest residential areas and Gulfside Elementary School are north of the Site. The grassy area
just east of the slag processing area represents the most critical (closest) area of concern for a
 maintenance worker.  Based on the location of these receptors (maintenance worker, pupils at
 school, and nearby residents), winds from the south and west would provide the most critical wind
 conditions.  Also, in order for wind erosion to occur from limited  reservoir surfaces, wind speeds
 of approximately 22 miles per hour would be required. Since the average annual wind speed in the
 Tarpon Springs area is only 10 to 15 miles per hour in the afternoon and 5 to 10 miles per hour at
 night, and the prevailing winds in the Tarpon Springs area are from the north and east, it is
 assumed that exposure via inhalation of fugitive dust does not present a significant exposure
pathway.  Therefore, the air pathway was not quantitatively evaluated as an exposure pathway for
particulate emissions.

The maintenance worker was quantitatively evaluated for exposure to surface soil via incidental
ingestion and dermal contact.
       Current Off-Site Resident

The Anclote River is classified as a Fish and Wildlife Class Ill-marine surface water body. Class
Ill-marine surface waters are defined as suitable for fishing and swimming.  Stormwater runoff and
groundwater discharge flow directly into the Anclote River; therefore, it is assumed that nearby
residents may be exposed to Site-related contaminants during recreational and fishing activities.

                                   Page 27 of   61

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                                                                           5   9       0035
 Direct contact with surface water and sediment was evaluated for an adult resident (age 7 to 30).
 Potential exposure routes included incidental ingestion and dermal contact with surface water and
 sediment. It was assumed that children under the age of seven would be under parental
 supervision and any direct exposure to the river would be negligible. An additional pathway that
 was evaluated for the off-Site resident (child and adult) included ingestion of contaminated fish
 that are caught in the Anclote River.

        Future Resident

 Based on surrounding land use, it was assumed that residential development might occur on-Site in
 the future. Potential pathways through surface soil exposure included in incidental ingestion and
 dermal contact.  Sediment and surface water exposure, were identical to that discussed in the
 current use scenario. These pathways included incidental ingestion and dermal contact using the
 adult (age 7-30 years) as the likely exposure receptor, and ingestion of locally  caught fish (age 1-
 30 years).  Ground water was evaluated due to the hypothetical possibility of future contamination
 of off-Site private drinking wells or the installation of a residential well on-Site. The potential
 exposure pathways involved the ingestion of drinking water.
       6.3.2  Summary of Radiological Exposure Scenarios

The scenarios considered for potential intakes to radioactive material are summarized in Table 6-5
and 6-6, along with the radiological data used for the risk assessment.

Table 6-5 presents the analytical results of Samples collected during the Remedial Investigation as
it relates to the assumptions used in the risk assessment and potential receptor scenarios.

Table 6-6 presents the estimated individual radiological pathway and cumulative radiological
pathways exposure risk scenarios. The potential receptors are listed in the first row. Exposure
scenarios are presented in the first column.
                                   Page  28  of   61

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                                                                   5  9      00
 • f
J 0
                                  Table 6-2
             Contaminants of Concern that Pose a Carcinogenic Risk
                Greater Than 10"* for Pathways That Exceed 1Q-*
Exposure
Medium/
Pathway
Surface Soil





Surface Water
Sediment
Current/Future
Maintenance
Worker
NONE





NE*
NE*
Current
Off-Site
Resident
NE*





NONE
NONE
Future
On-Site
Resident
Benzo(a)anthracene 	 2x10"*
Benzo(a)pyrene 	 2 x 10"5
Benzo(b)fluoranthene 5x10"*
Dibenzo(a,b)anthracene 	 4 x 10"*
Indeno(l,2.3-cd)pyrene 	 2 x 10*
Arsenic 	 3 x 10"4
Beryllium 	 6 x 10"*

NONE
NONE
Note that NE means that the pathway was not evaluated for this receptor.
                            Page 29  of   61

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                                                   Table 6-3
                        Contaminants of Concern with a Hazard Quotient Greater Than 0.1 for
                                   Pathways with a Hazard Index Exceeding 1.0
Exposure
Medium/
Pathway
Surface Soil

Surface Water

Sediment
Current/Future
Maintenance Worker
Arsenic 	 4 x 10"'
Thallium 	 1 x 10'1
NE

NA
Current Off-Site
Resident Adult
NE

Arsenic 	 2 x 10*'
Mercury.... 4
NA
Future On-Site
Resident Adult
Arsenic 	 6x 10"1
Thallium....! x 10'1
Arsenic 	 2x 10"'
Mercury 	 4
NA
Future On-Site
Resident Child
Fluoride .6x10''
Antimony.. 6 x 10"'
Arsenic 	 6
Cadmium.. 7 x 10'1
Thallium...!
Arsenic 	 2x 10"1
Mercury 	 4
NA
Notes:
            **
NE means that the pathway was not evaluated for this receptor.
NA means that all hazard indices were less than 1.0 for sediment.
                                                    Table 6-4
                         Comparison of Maximum Detected Concentrations of Lead to ARARs
Surface Soil
(mg/kg)
324
Residential Cleanup Levels
(mg/kg)
500
                                               Page  30 of   61

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                                                 5
0038
Table 6-5 Scenarios Analyzed for the Radiological Risk Analysis
Scenario
Incidental Ingestion of Soil
Ingestion of Vegetation Grown on
Contaminated Soil
Direct Irradiation by Contaminated
Soil
Inhalation of Rn- Indoor
222 Exposure
Outdoor
Exposure
Incidental Ingestion of Sediment
Ingestion of Groundwater
Irradiation by Roadbed Material
Potential Receptor
1. Current/Future Worker
2. Future On-Site Adult Resident
3. Future On-Site Child Resident
1 . Future On-Site Adult Resident
2. Future On-Site Child Resident
1. Current/Future Worker
2. Future On-Site Adult Resident
3. Future On-Site Child Resident
1. Current/Future Worker
2. Future On-Site Adult Resident
3. Future On-Site Child Resident
1. Current Off-Site Adult Resident
2. Current Off-Site Child Resident
1. Current Off-Site Adult Resident
1. Future On-Site Adult Resident
2. Future On-Site Child Resident
I. Current/Future Worker
2. Future On-Site Adult Resident
3. Future On-Site Child Resident
Monitoring Data Used to
Assess Risk
Surface Soil
Ra-226: 73.8pCi/g
Pb-2IO: 73.8pCi/g
Ra-228: 29.3 pCi/g
U-238: 29.1pCi/g
U-235: 0.7 pCi/g
Ac-227: O.R pCi/g
Th-228: 0.2 pCi/p
Surface Soil
(as above)
Surface Soil
(as above)
Rn-222 Flux:
8l36pCi/nr/hr
Sediment
Ra-226: 2.4 pCi/g
Groundwater
Ra-226: 24.9pCi/l
Radiation Survey
Measurements of On-Site
Roadway
ISOuR/hr
                 Page 31  of  61

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                                                                                   5   9        0039
             Table 6-6  Estimated Radiological Risk Considering Major Pathways
   Exposure
   Scenario
                      Current/
                       Future
                      Worker
   Current
Off-Site Adult
  Resident
   Future
On-Site Adult
  Resident
   Future
On-Site Child
  Resident
  Current
Off-Site Child
  Resident
   Incidental
   Injzestionof Soil
   Ingcstion of
   Vegetation Grown
   on Contaminated
   Soil
   Irradiation by
   Contaminated
   Soil
  Inhalation of
  Rn-222 (Indoor
  Exposure)
  Inhalation of
  Rn-222 (Outdoor
  Exposure)
  Incidental
  Ingestion of
  Sediment
  Ingestion of
  Groundwater
  Irradiation by
  Roadbed Material
NOTE:  Shaded boxes indicate that the given exposure scenario is not applicable for the indicated
receotor.
                                      Page  32  of   61

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                                                                               5   9       0044
 6.4    Ecological Risks

 The objective of ecological risk assessment was to use available toxicological and ecological
 information to estimate the probability that some undesired ecological event will occur. The
 baseline ecological risk assessment (BERA) evaluated the actual and potential risks to the
 environment due to releases of contaminants at the Site.  The general objective of a BERA is to
 provide the information necessary to assist in the decision-making process at remedial Sites.

 Media of concern for ecological receptors generally include surface water, sediments, surficial soil,
 and air.  These are media that may have direct or indirect effects on the community and population
 composition of an ecological habitat or on individual species that are pan of those communities or
 populations.

 Ecological chemicals of concern may often include more individual chemicals than the human
 health assessment because the screening criteria for human health do not apply to ecological
 receptors. As a result, different screening criteria are used to limit the chemicals evaluated in the
 ecological assessment. The preliminary list of ecological chemicals of concern initially included all
 chemicals detected during previous environmental sampling events. No protected species were
 found at the Site This list was then evaluated as follows:

 1)     Chemicals were eliminated if they  were not detected in RI/FS environmental samples.

 2)     Inorganic chemicals were eliminated if the detected concentrations did not exceed the
       sample quantitation limit or the background concentration (provided that the sample
       quantitation limit or the background concentration do not themselves exceed screening
       levels).

 3)     Organic chemicals were  eliminated if the detected  concentrations did not exceed the sample
       quantitation limit (provided that the sample quantitation limit itself does not exceed
       screening levels).

4)     All chemicals were eliminated if they were only tentatively identified.

5)     All chemicals with a low frequency of detection (less than 5 % for each medium) were
       eliminated from consideration.

6)     All chemicals in ground water for which the range of detection did not exceed the Region 4
       Screening Values were eliminated from consideration.

7)     Chemical concentrations in sediments that did not exceed the screening values established
       by Region 4 for hazardous waste Sites were eliminated.
                                   Page 33  of   61

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                                                                          5   9       OG43

 The following is a list of contaminants which include all those exposure point concentrations which
 exceed screening concentrations.

               Table 6-7  Ecological Summary of the Contaminants of Concern
Contaminants of Concern for Ecological Risk
Aluminum
Arsenic
Cadmium
Copper
Iron
Mercury
Nickel
Phosphorus
Silver
Thallium
^^== — =====^IL
Acenaphthalene
Anthracene
Benzo(a)pyrene
Bis(2-ethylhexyl)phthalate
Chrysene
Dibenz(a,h)antnracene
Fluorene
Fluoranthene
Phenanthrene
Pyrene
Zinc
The overall risk to the extended community on or immediately adjacent to the Stauffer Chemical
Site is considered low to moderate.  Causes for concern are that several contaminants currently
exceed screening values in both sediment and surface water.  In addition several contaminants were
detected in shallow groundwater samples at relatively high concentrations and would be expected
to contribute to the overall contaminant load in the adjacent wetland and deepwater habitats.
Moderating the overall risk to the extended community is the dilution effect of the Anclote River
and the tendency of the wetlands adjacent to the Site to partition some contaminants to deeper
sediments, restricting their effect to a limited area.  Based on information currently available to the
EPA contractor, the BERA was developed primarily based on chemical contaminants since
minimal information was found on the ecological impact of radiological contamination. All
available information concerning the ecological impact of chemical and radiological contamination
was considered in the decision making process. Further ecological or eco-toxicological
investigation is not warranted at the Site.
                                  Page 34  of   61

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                                                                           5   9       0042
 .6.5    Cleanup Levels
 Cleanup levels for the Site were established to ensure that any person exposed in the future will not
 be exposed to unsafe levels of Site-related chemicals. Cleanup levels are either the Federal
 Maximum Contaminant Limits (MCLs), other Applicable or Relevant and Appropriate
 Requirements (ARARs), or risk-based concentrations.  At the Site, EPA requires that  soil be
 remediated up to a 10* residential risk level for cancer causing contaminants and a Hazard Index
 (HI) of 1  for non-carcinogenic chemicals.  For the radiological contamination, a ARAR is used as
 the cleanup standard. These levels are consistent with the National Contingency Plan (NCP) and
 EPA requirements for cleanup levels of carcinogenic chemicals with in the 10 a to 10 "* risk range
 and are protective of human health and the environment in a residential setting.  This risk range of
 10~* to 10** means that exposure to Site-specific contaminants as defined as in the risk  assessment
 would result in an estimated increase in an individual's chance of developing cancer ranging from
 one in ten thousand to one in a million.  For non-cancer causing risks, EPA compares the highest
 dose known to be safe (not cause harmful effects) to the estimated dose from exposure to levels
 found on-Site. These comparisons were used to develop cleanup levels for Contaminants of
 Concern for the soil/waste at the Site.  Elemental phosphorus is a CERCLA listed Hazardous
 Substance.

 Arsenic, a Contaminant of Concern at this Site, is a naturally occurring mineral that is considered
 by EPA to be a systemic toxicant and a human carcinogen. However, there is considerable
 uncertainty concerning its ability to cause cancer at low exposure levels, especially the less soluble
 form that occurs in contaminated soil. The Superfund program of EPA Region 4 regulates arsenic
 in soil as a  systemic toxicant in deriving protective cleanup levels. As an additional precaution,
EPA also requires soil cleanup levels to fall within the protective cancer risk range of 10"4 to 10"6
for the most sensitive likely receptor even though the calculated risk may be significantly over
predictive.  The co-location of arsenic with other contaminants that are to be addressed in soil
remediation will likely result in soil arsenic residuals at the more protective end of the calculated
risk range.
                                   Page  35  of   61

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                                                                 5  9
OC
                                  Table 6-8
                     Cleanup Standards: Remedial Goals
Soil/Waste Contaminant
Arsenic
Antimony
Beryllium
Elemental Phosphorus
Thallium
Radium-226 (Lead-210)*
Total CPAHs**
Maximum Concentration
Detected (mg/kg)
127
32.3
1.6
0.854
13.4
73.8 pCi/g
—
Remedial Cleanup Goals
(mg/kg)
#
28.1
0.192
1.4.
1.4
5pCi/g
0.089
*   Note that this cleanup level is measured above the background (normal) concentration.
     The background (normal) concentration will be established during the Remedial
     Design.

**   Total CPAHs include Benzo(a)anthracene, Benzo(a)pyrene, Benzo(b)fluoranthene,
     Dibenzo(a,h)anthracene, and Indeno(l,2,3-cd)pyrene.

#      EPA Region 4 regulates arsenic in soil as a systemic toxicant with a reference dose
       of 0.0003 mg/kg/day. The safe soil level for residential use that would not exceed
       this RfD for a child was determined in the Site's risk assessment to be 21.1 mg/kg.
       EPA also considers arsenic to be a carcinogen in the form that may occur in
       drinking water and has included an oral slope factor in its IRIS database. The
       application of the slope factor here, though not considered appropriate, would yield
       a calculated safe soil level for a child at the most protective 10"* risk level of 0.46
       mg/kg. The latter soil cleanup level for arsenic is likely to be achieved since soil
       containing arsenic above this level also contains other contaminants that will require
       remediation.
                            Page  36  of   61

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                                                                       5   9       OU4Q

 All Cleanup Standards have been derived from the Final Baseline Risk Assessment with the
 exception of Radium-226 which has been establish in accordance with the relevant and appropriate
 requirement (Federal Standards for the Cleanup of Land and Buildings Contaminated with
 Residual Radioactive Material 40 CFR 192).
7.0    DESCRIPTION OF REMEDIAL ACTION ALTERNATIVES

Remedial action alternatives were formulated to address the environmental contamination at the
Site. Seven remedial action alternatives were considered for the Site through the Final Feasibility
Study Report. The alternatives in this ROD address the source of contamination at the Site
(Operable Unit 1). Alternative 6 will not be evaluated in this document since groundwater will be
addressed in a separate operable unite.  The seven considered remedial action alternatives include:

     •   Alternative 1: No Action with Continued Monitoring

     •   Alternative 2: Institutional Controls

     •   Alternatives 3a and 3b: Consolidation and Cover (Commercial and Residential)

     •   Alternatives 4a and 4b: Consolidation and Capping (Commercial and Residential)

     •   Alternatives 5a and 5b: Consolidation, Capping, and Saturated Zone Source Control
         (Commercial and Residential)

     •   Alternatives 7a and 7b: Consolidation, Stabilization, and Cover (Commercial and
         Residential).
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                                                                      5  9       0045
                                        Table 7-1
             Response Actions and Associated Remedial Technologies Screening
l|| i i i • i ii ii — •a^— S
III General Response Action
Elemental Phosohorus-
Containine Material
No Action 	 .,
Institutional Controls
II Treatment
II Site Soil
II No Action
Institutional Controls
Excavation/Consolidation
Containment
1 Treatment
Associated Remedial Technologies
Considered after the Screening Process


None
Access restrictions
Land use restrictions
Groundvvater monitoring
Conversion to phosphoric acid
Incineration
Aqueous oxidation
Low temperature air oxidation
Stabilization/Solidification

None
Access restrictions
Land use restrictions
Groundwater monitoring
Groundwater use restrictions
Excavation and Consolidation of
affected soil
Capping/Cover
Liner
Stabilization/Solidification
Volume rediirfiniL
A summary of how the alternatives address affected media and the associated technologies utilized
are presented in Table 7-2.

Alternative 1; No Action

The No Action Alternative is carried through detailed evaluation as a point of reference to the
other alternatives. For this PS, it is assumed that groundwater monitoring would be continued,
even if no further remedial action were initiated.

Alternative 2: Institutional Controls

Institutional controls provide some degree of control of future land use.  As was the case under the

                                  Page 38  of   61

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                                                                           5   9       0046
  no action alternative, groundwater and surface water monitoring would be provided and in
  addition, the property fence would be maintained. In addition, deed restrictions would be placed
  on the property, which would not allow it to be developed for residential use, nor for any
  commercial activities requiring that personnel be assigned to the Site.  Furthermore, the deed
  restrictions would preclude the installation of any groundwater wells in the surficial aquifer beneath
  the Site.

  Alternative 3a; Consolidation and Cover (Commercial Use)

  Alternative 3a, Consolidation and Cover, consists of the evacuation, consolidation, and cover of
  radiological and chemical waste material on-Site.  All waste material, above commercial use action
  levels, would be consolidated in several different areas. By utilizing several areas the movement of
  contaminated material will be minimized. In addition to radiologically and chemically identified
  contaminated material, waste present in Ponds 39 and 42 along with other contaminated soil and
  waste would be excavated and placed in the consolidation areas. The consolidation areas would
 then be covered with a layer of soil, sufficient to reduce radiological exposure and support a
 vegetative cover to prevent wind or soil erosion of this material. Any existing locations of soil
 contamination, over which this soil cover would be placed, would not require excavation because
 the soil would be covered in place.

 Radiologically contaminated material would be consolidated and covered in several locations if
 they  exceed 5 pCi/g above background for surface soil. The areas above the surficial limit includes
 much of the developed  Plant area.  Areas where the 5 pCi/g above background criterion is
 exceeded are comprised of the slag processing area, roads,  railroads, and parking lots.

 As with the Institutional Controls Alternative, groundwater and surface water monitoring would be
 continued, and the fences which currently surround the entire property would be maintained.
 Notification of Site conditions would be included in the property deed to alert prospective buyers
 of Site conditions and deed restrictions would be implemented.  These restrictions would prohibit
 future development of the covered pond areas, and would restrict the remainder of the Site to
 commercial use.  A final restriction would be that no surficial groundwater wells, for any purpose,
 could be installed on any portion of the property.

 Alternative 3b; Consolidation and Cover (Residential Use)

 This alternative includes the same remediation activities and institutional controls noted for
 Alternative 3a, except that remediation action levels and deed restrictions would be based on
 future residential use of the Site.  Compared to Alternative 3 a, this alternative would require
 additional remediation of radiologically and chemically contaminated soil due to lower cleanup
goals for residential use. Based on residential cleanup goals, radiologically contaminated material
would be remediated if they exceed 5 pCi/g above background for soil, regardless of depths. The
areas requiring remediation under the residential land use scenario encompass those for the
commercial use scenario plus all soil that has radiation levels between 5 and 15 pCi/g at depths
greater than 15 cm.  In addition to the areas described for commercial use, an additional area in the

                                   Page 39  of   61

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                                                                             5   9       0047
 west central portion of the Main Plant Area would require remediation at depth to meet the 5
 pCi/g above background standard.

 In addition to excavating and consolidating radiological contaminated material/soil and Ponds 39
 and 42, soil exceeding a chemical carcinogenic risk level of 1 x 10"06 or a hazard index of 1.0
 would also be excavated and placed in one of the consolidation areas. As noted in Alternative 3a,
 locations over which cover would be placed would not be excavated.

 Alternnfive 4a; Consolidation and Capping (Commercial Use)

 This alternative includes the same activities and institutional controls noted for Alternative 3a:
 excavation and consolidation of radiologically and chemically contaminated material/soil in several
 consolidation areas exceeding commercial use levels.  However, under this alternative, the
 consolidated material in the main pond areas would be capped, rather than covered, to further
 decrease the potential migration of contaminants from the consolidated material into the surficial
 aquifer. A synthetic membrane and drainage system would be included as part of the cap.

 In addition to reducing contaminant  migration into the surficial aquifer, based on the Soil Cover
 Depth Study (WESTON, 1994a) findings, the cap would reduce gamma radiation exposure to
 someone working on the cap. Under the Consolidation and Capping Alternative, institutional
 controls would prevent the development of the capped area; therefore, reducing the gamma
 radiation exposure. Also, the synthetic membrane of the cap would reduce the escape of radon gas
 from the consolidation area.

 As with the Institutional Controls Alternative, groundwater and surface water monitoring would be
 continued, and the fences which currently surround the entire property would be maintained.
 Notification of Site conditions would be included in the property deed to alert prospective buyers
 of Site conditions and deed restrictions would be implemented. These restrictions would prohibit
future development of the covered pond areas, and would restrict the remainder of the Site to
commercial use. A final restriction would be that no surficial groundwater wells, for any purpose,
could be installed on any portion of the property.

Alternative 4b: Consolidation and Capping (Residential Use)

This alternative includes the same activities and institutional controls noted for Alternative 3b:
excavation and consolidation of radiologically and chemically contaminated material/soil found on
Site exceeding residential use levels.  However, under this alternative, the consolidated material at
locations on-Site would be capped, rather than covered, to further decrease the potential migration
of contaminants from the consolidated material into the surficial aquifer. The cap would be
constructed in the same way as mentioned in Alternative 4a. Based on residential cleanup goals,
radiologically contaminated material would be remediated if they exceed 5 pCi/g above
background for soil, regardless of depths. The areas requiring remediation under the residential

                                   Page  40  of   61

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                                                                            5   9       OG48
 land use scenario encompass those for the commercial use scenario plus all soil that has radiation
 levels between 5 and 15 pCi/g at depths greater than 15 cm.  In addition to the areas described for
 commercial use, an additional area in the west central portion of the Main Plant Area would
 require remediation at depth to meet the 5 pCi/g above background standard.

 Alternative 5a: Consolidation, Capping, and Saturated Zone Source Control (Commercial
 Use)

 This alternative includes the same activities and institutional controls noted for Alternative 4a
 (excavation, consolidation, and capping), plus a provision to further reduce contaminant migration
 to the surflcial aquifer by in situ solidification, and subsequent immobilization, of contaminants
 within pond material that are below the water table. In situ solidification would be performed by
 injecting and mixing admixtures/binding agents into the saturated pond material to form a solid,
 low permeability matrix.  Contaminants would be bound in the matrix, unable to migrate into the
 surficial aquifer..

 As with the Institutional Controls Alternative, groundwater and surface water monitoring would be
 continued, and the fences which currently surround the  entire property would be maintained.
 Notification of Site conditions would be included in the property deed to alert prospective buyers
 of Site conditions and deed restrictions would be implemented.  These restrictions would prohibit
 future development of the covered pond areas, and would restrict the remainder of the Site to
 commercial use. A final restriction would be that no surficial groundwater wells, for any purpose.
 could be installed on any portion of the property.

 Alternntive 5b: Consolidation. Capping, and Saturated Zone Source Control CResidentinl
 Use)

 This alternative includes the same activities and institutional controls noted for Alternative 4b
 (excavation, consolidation, and capping), plus the provision identified in Alternative 5a for in situ
 solidification, and subsequent immobilization, of pond material below  the water table.

 Based on residential cleanup goals, radiologically contaminated  material would be remediated if
 they exceed 5 pCi/g above background for soil, regardless of depths. The areas requiring
 remediation under the residential land use scenario encompass those for the commercial use
 scenario plus all  soil that has radiation levels between 5 and 15 pCi/g at depths greater than 15 cm.
 In addition to the areas described for commercial use, an additional area in the west central portion
 of the Main Plant Area would require remediation at depth to meet the 5 pCi/g above background
 standard.

Alternative 7a;  Consolidation. Stabilization, and Cover (Commercial Use)

This activity is similar to Alternative 5a, where material below the water table was stabilized.
Under Alternative 7a, all material in one of several consolidation areas would be treated by
stabilization. This would include all soil, pond material, and slag material. In-situ stabilization

                                   Page  41 of   61

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                                                                            5   9       0049
 would generally be used for material presently located within the pond area; ex-situ stabilization
 would be performed on excavated material.  A combination of material stabilization and placement
 of a soil cover will reduce contaminant migration and shield low-level radiation.

 As with the Institutional Controls Alternative, groundwater and surface water monitoring would be
 continued, and the fences which currently surround the entire property would be maintained.
 Notification of Site conditions would be included in the property deed to alert prospective buyers
 of Site conditions and deed restrictions would be implemented.  These restrictions would prohibit
 future development of the covered pond areas, and would restrict the remainder of the Site to
 commercial use.  A final restriction would be that no surficial groundwater wells, for any purpose,
 could be installed on any portion of the property.

 Alternative 7b: Consolidation. Stabilization, and Cover (Residential Use)

 This alternative would provide the same treatment and capping identified for Alternative 7a.
 However, the extent of soil excavated/stabilized would be expanded to meet residential use
 criteria.

 Based on residential cleanup goals, radiologically contaminated material would be remediated if
 they exceed 5 pCi/g above background for soil, regardless of depths. The areas requiring
 remediation under the residential land use scenario encompass those for the commercial use
 scenario plus all soil that has radiation levels between 5 and 15 pCi/g at depths greater than 15 cm.
 In addition to the areas described for commercial use, an additional area in the west central portion
 of the Main Plant Area would require remediation at depth to meet the 5 pCi/g above background
 standard.
8.0   SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES

8.1   Comparative Analysis - Nine Criteria

This section of the ROD provides the basis for determining which alternative provides the best
balance with respect to the statutory balancing criteria in Section 121 of CERCLA, 42 USC  9621,
and in the NCP, 40 CFR 300.430.  The major objective of the feasibility study (FS) was to
develop, screen, and evaluate alternatives for the remediation of the Site.  A wide variety of
alternatives were identified as candidates to remediate the contamination at the Site. These were
screened based on the contaminants present and Site characteristics. After the initial screening,
the remaining alternatives/technologies were combined into potential remediation alternatives and
evaluated in detail. The selected remedial alternative emerged from the screening process using
the following nine evaluation criteria:

      •  Overall Protection of Human Health and the Environment
      •  Compliance with ARARs
      •  Short-Term Effectiveness

                                  Page  42  of   61

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                                                                         5  9       UubO
          Long-Term Effectiveness and Permanence
          Reduction ofToxicity, Mobility, and Volume of Contaminants
          Implement ability
          Cost
          State Acceptance
          Community Acceptance
 The NCP Categorizes the nine criteria into three groups:

        (1)  Threshold Criteria - overall protection of human health and the environment and
            compliance with ARARs (or invoking a waiver ) are threshold criteria that must be
            satisfied in order for an alternative to be eligible for selection;

        (2)  Primary Balancing Criteria. - long-term effectiveness and permanence; reduction
            of toxicity, mobility, or volume; short-term effectiveness; implementability; and
            cost are the primary balancing factors used to weigh major trade-offs among
            alternative hazardous waste management strategies; and

        (3) Modifying Criteria - state and community acceptance are the modifying criteria
            that are formally taken into account after public comments are received on the
            proposed plan and incorporated into the ROD.

The following analysis is a summary of the evaluation of alternatives  for remediating the Site under
each criteria. A comparison is made between each of the alternatives for achievement of a specific
criterion.

8.2   Threshold Criteria

8.2.1  Overall Protection of Human Health and the Environment

With the exception of the No Action Alternative (Alternative 1) and the Institutional Controls
Alternative (Alternative 2), all of the alternatives would provide protection for human health and
the environment to some degree. Alternatives 3, 4, 5, and 7 would limit access and exposure.  By
simply consolidating and capping or covering the contamination, the contamination would still be
available to be transported off-Site through the groundwater. Therefore, only alternatives 5 and 7
provide scenarios in which the source of contamination has been controlled. Alternatives 5 and 7
would limit the migration of contaminants and contain the contaminants within the Site boundaries.
     8.2.2 Compliance with ARARs

The remedial action for the Site, under Section 121(d) of CERCLA, must comply with federal and
state environmental laws that either are Applicable or Relevant and Appropriate Requirements

                                   Page  43  of   61

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                                                                            5   9      0051
 (ARARs). Applicable requirements are those standards, criteria, or limitations promulgated under
 federal or state law that specifically address a hazardous substance, pollutant, contaminant,
 remedial action, location or other circumstance at a CERCLA Site. Relevant and Appropriate
 Requirements are those that, while not applicable, still address problems or situations sufficiently
 similar to those encounter at the She and that their use is well suited to the particular Site.  To-Be-
 Considered Criteria (TBCs) are non-promulgated advisories and guidance that are not legally
 binding, but should be considered in determining the necessary level of cleanup for protection of
 human health or the environment. While the TBCs do not have the status of ARARs, EPA's
 approach is to determine if a remedial action is protective to human health and the environment
 involves consideration of TBCs along with ARARs.

 Location-specific ARARs are restrictions placed on the concentration of hazardous substances or
 the conduct of activities solely on the basis of location .  Examples of location-specific ARARs
 include state and federal requirements to protect floodplains, critical habitats, and wetlands, and
 solid and hazardous waste facility siting criteria.   Table 8-1 summaries  the potential location
 specific ARARs and TBCs for the Site.

 Action-specific ARARs are technology- or activity-based requirements or limitations on actions
 taken with respect to hazardous wastes. These requirements are triggered by particular remedial
 activities that are selected to accomplish a remedy. Since there are usually several alternative
 actions for any remedial Site, various requirements can be ARARs . Table 8-2 lists potential
 action-specific ARARs and TBCs for the Site.
                                          *
 Chemical-specific ARARs are specific numerical quantity restrictions on individually listed
 contaminants in specific media.  Examples of chemically-specific ARARs include the MCLs
 specified under the Safe Drinking Water Act as well as the ambient water quality criteria that are
 enumerated under the Clean Water Act. Since there are usually numerous contaminants of
 potential concern for any remedial Site, various numerical quantity requirements can be ARARs.
 Table 8-3 lists potential chemical-specific ARARs.

Alternatives 4, 5, and 7 met or exceed  all ARARs (action-, location-, and chemical-specific).
Alternative 4 currently meets surface water ARARs, but this alternative may not provide a
permanent solution for the surface water.  Alternatives 1, 2, 3, and 4 would leave  the
contamination in a state where it is still available to move off-Site through the surficial aquifer.
                                  Page  44  of  61

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                                                                         5  9      0052
                                       Table 8-1
                               Location-Specific ARARs
  Applicable (A) or
    Relevant &
    Appropriate
      (R&A)
        Citation
                Comments
 R&A
 RCRA
 Disposal Subtitle D
 40 CFR 258.40
 Outlines top cover design criteria.
 R&A
 Land Disposal
 Restrictions
 40 CFR Part 268
 Identifies hazardous wastes that are restricted
 from land disposal and describes those
 circumstances under which an otherwise
 prohibited may be land disposed.
 R&A
 Endangered Species-Act
 42 USC 6901, 6905,
 6912, & 6925
 Only applies if threatened or endangered
 species or critical habitats of the endangered
 species are identified near the Site.
R&A
 Coastal Zone
 Management Act
 16USCSec.l951etseq.
 It is national policy to preserve, protect, and.
 when possible, restore costal land.
 R&A
FDEP Solid and
Hazardous Waste
FAC 62-296.705
Regulations include closure and operations&
maintenance requirements.
R&A
FAC 62-701.050
Regulations cover the criteria for the top
cover design.
R&A
Rivers and Harbors Act
of!899(SectionlO
Permit) 33 USC Sec 403
Requires that the substantive requirements of
permits for work in affected navigable waters
be met.
R&A
Floodplain Management
Executive Order 11988,
40 CFR 6.302
Activities that occur in the floodplain should
avoid adverse effect, minimize potential harm,
and preserve natural and beneficial values.
                                 Page 45 of   61

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                                                                       5  9      0053
                                      Table 8-2
                               Action-Specific ARARs
Applicable (A) or
    Relevant &
   Appropriate
     (R&A)
        Citation
               Comments
                   Identification and Listing
                   of Hazardous Waste
                   40CFRPart261
                         Identifies those solid wastes which are subject
                         to regulation as hazardous waste. Defines
                         "hazardous waste" and "solid waste"
R&A
Generators of Hazardous
Waste
40 CFR Part 262
Establishes Standards for generators of
hazardous waste.
R&A
Transporters of
Hazardous Waste
Establishes the responsibility of generators
and transporters of hazardous waste.
                   Owners and Operators of
                   Hazardous Waste
                   Treatment, Storage, and
                   Disposal (TSD) Facilities
                   40 CFR 264
                        Establishes minimum national standards for
                        which define the acceptable management of
                        hazardous waste for owners and operators of
                        facilities which treat, store, or dispose of
                        hazardous waste.
                                Page 46 of   61

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                                                                         5  9      0054
                                      Table 8-3
                               Chemical-Specific ARARs
  Applicable (A) or
    Relevant and
   Appropriate
      (R&A)
        Citation
  R&A
 To Be
 Considered*
Federal Standards for the
Cleanup of Land and
Buildings Contaminated
with Residua]
Radioactive Material
40CFR192
National Oceanic and
Atmospheric
Administration (NOAA)
(Effects Range Low,
Effects Range Medium,
& Effects Range High)
               Comments
Establishes soil and waste standards for
radioactive constituents at the Site.
Guidance that evaluates sediment values.
     Note that additional To Be Considered requirements are found in Section 9.2 Performance
Standards.
                                Page  47 of   61

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                                                                             5   9      Du55


 8.3   Primary Balancing Criteria

       8.3.1 Long-Term Effectiveness and Permanence

 Alternatives 5 and 7 are effective and permanent, but both would require a period of time to reach
 a clean and safe condition. Alternative 4, as stated above, is not a permanent source control
 alternative.  Under Alternative 4, the contamination remains uncontrolled and may allow a future
 release to the surface water.


       8.3.2 Reduction in Toxicitv. Mobility, or Volume Through Treatment

 Alternative 4 would have a limited impact on the mobility of contaminants by slowing the
 horizontal migration of contamination.  However, the toxicity and volume would not be reduced.
 Alternative 7 would be the most effective in immobilizing and shielding all the contaminants. Also,
 Alternative 7 contains the toxic material by binding these contaminants into a relatively
 impermeable matrix.  This alternative does have one drawback - it would provide a dramatic
 increase in volume.

 Alternative 5 provides the best balance of the feasible alternatives. By utilizing a top cover and
 solidification. Alternative 5 effectively contains the Site-related contamination. Toxic material is
 rendered immobile, and the volume increase would be limited and small compared to Alternative
 7's increase.


      8.3.3  Short-Term Effectiveness

 Alternative 1 is the only alternative that is completely ineffective in the Short-Term. Alternative 2
 which restricts access and places institutional controls on the Site would be effective in the Short-
 Term. Alternatives 3, 4, 5 and 7 would represent minor short-term risks related to excavation and
 construction activities.


      8.3.4 Implementabilitv

 The implementability of an alternative is based on technical feasibility, administrative feasibility and
 the availability of services and material.  Alternative 2 involves only access restrictions and deed
 restrictions, which are easily implemented, given a cooperative property owner.  Alternative 3 and
4 are relatively easy to implement since most of the contaminated soil located in the top
cover/consolidation area. Alternative 5 and 7 would require pilot studies and would require more
additional work to complete their solidification  components.
                                   Page 48  of   61

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                                                                          5   9       0056
      8.3.5 Cost
 A summary of the present worth costs which include capital as well as operations and maintenance
 costs for each alternative is presented in Table 8-5.These cost were presented in the FS.  The
 present worth costs to attain the recommended performance standards (Section 9.2) and to meet
 the requirements of the compliance testing (Section 9.3) must remain within the range which is
 considered accurate (+50% or -30% of the present worth cost).
 Alternative 2 is the least costly alternative, other than the No Action alternative. Of the treatment
 alternatives. Alternative 5 is less expensive than Alternative 7 and affords the same level of
 protection.  The residential scenarios are only slight more expensive than the commercial use
 scenarios, but the residential scenarios are found to be the more protective than the commercial
 scenarios.
 8.4   ModifVine Criteria

      8.4.1 State Acceptance

 The State of Florida, as represented by the Florida Department of Environmental Protection
 (FDEP), has been the support agency during the Remedial Investigation/Feasibility Study (RI/FS)
 process for the Site. In accordance with 40 CFR 300.430, FDEP as the support agency, has
 provided input during the process by reviewing and providing comments to EPA on all major
 documents in the Administrative Record.  Based upon comments received from FDEP, it is
 expected that written concurrence will be forthcoming; however, letter formally recommending
 concurrence with EPA's selected remedy has not been received.
      8.4.2 Community Acceptance

Based on written comments received during the extended comment period, it appear that the
public would prefer off-Site disposal; even though, it may be more expensive, more difficult to
implement, and riskier (may exposure them to the contamination). Atkemix Thirty-seven
Incorporated (the PRP) commented that they preferred the commercial use as opposed to the
residential use scenario. Zeneca does recommend Alternative 5.  Specific response issues raised by
the community and other interested parties are summarized in Appendix A, the Responsiveness
Summary.
                                  Page  49  of   61

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                                                          Table 8-4
                                          Summary of Remedial Action Alternatives
                                                 for the Tarpon Springs Site
                   Alternative
              Effectiveness
       Implementability
1.    No Action with Continued Monitoring
  Under this alternative no remedial action will be
  conducted at the Site.

  Long-term semi-annual groundwater and surface
  water monitoring will be conducted.

  Inspection and maintenance of facility fence to
  restrict access to Site will be conducted.
Compliance with ARARs will not be met.

Implementation of this alternative will cause
no additional environmental impact.

This alternative will not provide an effective
long-term solution for the Site.

Exposure to Site constituents will be limited
by access restrictions.

Toxicity, mobility, and volume of
contaminants are not changed in this
alternative.
• Can be readily implemented.

• No construction activities
  required.
2.   Institutional Controls
  Incorporation of features from the No Action with
  Continued Monitoring alternative with the addition
  of a caretaker.

  Internal fences at the slag processing area and the
  main pond area.

  Placement of deed restrictions prohibiting.

  -   installation of groundwater supply wells.

  -   excavation in designated areas where elemental
      phosphorus is known to exist.

  -   development of any portion of the properly for
      residential use.

  -   development of any portion of the property for
      commercial/industrial use unless approved by
      EPA.
Compliance with ARARs will not be met.

Implementation of this alternative will cause
no additional environmental impact.

This alternative will substantially reduce the
risk to human health in the long-term by:

-   insuring that the surficial aquifer will not be
    used in the future.

-   not allowing the Site to be used for
    residential use.

-   greatly restricting commercial or industrial
    tuture use.

Toxicity,  mobility, and volume of
contaminants are not changed in this
alternative.
                                                      Page 50  of   61
•  Can be readily implemented.

•  No substantive construction
   activities required.
                                   cn
                                                                                 O
                                                                                 o
                                                                                 01

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                   Alternative
              Effectiveness
       Implementability
3a and b.   Consolidation and Cover
  Excavation and consolidation of on-Site
  contaminated soil.  A soil cover will be placed over
  the consolidated material and the area will be
  fenced to restrict access.  The consolidation area
  will include the entire main pond area, plus
  additional ground to the north.

  Includes Excavation of Pond 39 and 42.

  Deed restrictions:

  -   prohibiting installation of groundwater supply
      wells.

  -   restricting the property to commercial/industrial
      use only rAlternattve 3a only; 3b allow
      residential use),

  •   prohibiting excavation or development of the
      consolidation area.

  Long-term semi-annual groundwater and surface
  water monitoring maintenance of facility fence, and
  grounds keeping.
Compliance with radiological ARARs. For
Alternative 3a (Commercial Use), this ARAR
js expressed as a concentration that will result
in a dosage equivalent to Alternative 3b
(Residential use). The capping, groundwater
Quality criteria, and surface water quality
ARARs would not be met.

This alternative will substantially reduce the
risk to human health in the long-term by:

-  isolating waste material from human and
   ecological contact.

•  insuring that the surftcial aquifer will not be
   used in the future.

.-  restricting the property td commercial use
   (Alternative 3a only).

A reduction in the mobility of the
contaminants is achieved by excavating the
slag processing area and Ponds 39 and 42, and
by covering the consolidation area.

Toxicity and volume of contaminants are not
changed in this alternative.
• Can be readily implemented.

• Excavation and cover
  construction are
  conventional operations.

• Shoring and slope
  stabilization may be required
  if groundwater is
  encountered during
  excavation activities.

• In the short-term,
  implementation of this
  alternative can be achieved
  without adverse effects on
  the environment. However,
  actions will be taken to limit
  potential risks involved in
  excavation, transport,
  placement and covering of
  soil/material.
                                                                                                                                    cn

                                                                                                                                    vo
                                                                                                                                    CD
                                                                                                                                    CD
                                                      Page 51 of   61
                                                                                                                                   CO

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                   Alternative
              Effectiveness
     Implementability
4a and b.   Consolidation and Capping
  Incorporation of institutional controls and waste
  isolation features from the Consolidation and
  Cover alternative. However, this alternative
  provides a cap, rather than a cover soil, over the
  consolidation area.
  The cap will comply with the FDEP regulations for
  capping solid waste management units.
Compliance with radiological and capping
ARARs.  Groundwater quality in the surticial
aquifer would improve, but the groundwater
and surface water quality criteria ARARs
would not necessarily be met.
This alternative will substantially reduce the
risk to human health in the long-term by:

-  isolating waste material from human and
   ecological contact.

-  insuring that the surficial  aquifer will not be
   used in the future.

-  restricting the property to commercial use
   (Alternative 4a only).

A reduction in the mobility of the
contaminants is achieved oy  excavating the
slag processing area and Ponds 39 and 42,
and by capping the  consolidation area.

Toxicity and volume of contaminants are not
changed in this alternative.	
Excavation and capping are
readily implementable
construction procedures.
Shoring and slope
stabilization may be required
if groundwater is
encountered during
excavation activities.

In the short-term,
implementation of this
alternative can be achieved
without adverse effects on
the environment. However,
actions will be taken to limit
potential risks involved in
excavation, transport,
placement, and covering of
soil/material.
                                                                                                                                    cn

                                                                                                                                    vo
                                                      Page  52  of   61
                                                                                o
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                   Alternative
              Effectiveness
      Implement ability
Sa and b.   Consolidation. Capping, and Saturated Zone Source Control
  Incorporation of features from the Consolidation
  and Capping alternative plus the additional
  remediation of pond material below the water
  table.

  Before consolidation and capping, waste material
  in the ponds below the water table will be
  solidified in place.
Compliance with radiological and capping
ARARs. Groundwater and surface water
quality ARARs will also be met, although not
immediately.

This alternative will substantially reduce the
risk to human health and the environment in
the long-term by:

-  isolating waste material from human and
   ecological contact.

-  preventing use of surficial aquifer until the
   remedial action objectives are achieved.

-  restricting the property to commercial use
   (Alternative 5a only).

A reduction in the mobility of the
contaminants is achieved By excavating Ponds
39 and 42, and the slag processing area, and
capping the consolidation area.  This, in
conjunction with remediating the pond
material below the water table, will prevent
further contamination of the surficial aquifer.

Toxicity and volume of contaminants are not
changed in this alternative.	
 The excavation/capping
 portions of this alternative
 can be readily implemented
 for the same reasons as
 outlined in the previous
 alternative. In situ
 solidification is a readily
 available technology,
 provided by several vendors,
 although a pilot study will be
 required before solidification
 can begin.

• In the short-term,
 implementation of this
 alternative can be achieved
 without adverse effects on
 the environment.  However,
 actions will be taken to limit
 potential risks involved in
  excavation, transport,
  placement, and covering of
  soil/material.
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                                                       Page 53  of   61

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                   Alternative
               Effectiveness
     Implementability
7a and b.   Consolidation, Stabilization, and Cover
  Incorporation of features from the Consolidation,
  Capping and Saturated Zone Source Control
  alternative (with the exception of cover instead of
  capping) plus the additional
  stabilization/solidification of all material in the
  consolidation area.

  Stabilization/solidification of all consolidation
  material would include all soil, pond material, and
  slag material.  In situ stabilization would generally
  be used for material presently tacated within the
  consolidation area; ex-situ stabilization would be
  performed on excavated material.
Compliance with radiological ARARs.
Groundwater and surface water quality
ARARs will also be met, although not
immediately.

This alternative will substantially reduce the
risk to human health and the environment in
the long-term by:

-  isolating waste material from human and
   ecological contact.

-  preventing use of surficial aquifer until the
   remedial action objectives are achieved.

-  restricting the property to commercial use
   (Alternative 7a only).

A reduction in the mobility of the
contaminants is achieved by excavating Ponds
39 and 42, and the slag processing area, and
by covering the consolidation area.  This, in
conjunction with stabilizing/solidifying the
consolidation material, wilTprevent further
contamination of the surficial aquifer.

Toxicity and volume of contaminants are not
changed in this alternative.            	
The excavation/cover
portions of this alternative
can be readily implemented
for the same reasons as
outlined in the previous
alternatives.  In situ and ex-
situ stabilization/
solidification is a readily
available technology,
provided by several vendors,
although a pilot study will be
required before stabilization/
solidification can begin.

In the short-term,
implementation of this
alternative can be achieved
without adverse effects on
the environment.  However,
actions will be taken to limit
potential risks involved in
excavation, transport,
placement, and covering of
soil/material.
                                                                                                                                     cn
                                                      Page 54  of    61
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                                                                       5   9       0062
                                       Table 8-5
                     Cost Comparison of Remedial Action Alternatives

1 -
2 -
3 -


4 -


5 -



Alternative
No Action with Continued Monitoring
Institutional Controls
Consolidation and Cover
3 a - Commercial Use
3b - Residential Use
Consolidation and Capping
4a - Commercial Use
4b - Residential Use
Consolidation, Capping, and Saturated Zone
Source Control
5a - Commercial Use
5b - Residential Use
Capital
Cost
($)
0
117,000

4,720,000
4,769,000

6,903,000
6,952,000


8,075,000
8,124,000
Annual O&M
Cost
($)
31,250
81,250

71,250


71,250



71,250

Present
Worth
Cost'
($)
540,000
1,522,000

5,952,000
6,001,000

8,135,000
8,184,000


9,307,000
9,356,000
7 - Consolidation, Stabilization, and Cover

    7a - Commercial Use
    7b - Residential Use
32,991,000       71,250      34,223.000
34,457,000                  35,689,000
'Based on a 30 Year Operation with a net interest rate of 4%. Includes both capital and O&M costs.
                                 Page 55  of   61

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                                                                          5  9       006.3

 9.0    SUMMARY OF SELECTED REMEDY

 Based upon the comparison of alternatives in the feasibility study (FS) and upon consideration of
 the requirements of CERCLA, the NCP, the detailed analysis of alternatives and public and state
 comments, EPA has selected Alternative 5b (Consolidating, Capping, and Zone Source Control -
 Residential Use Scenario)for the Site. The selected alternative for the Site is consistent with the
 requirements of Section 121 of CERCLA and the NCP. Based on the information available at the
 time, the selected alternative represents the best balance among the criteria used to evaluate
 remedies. The selected alternative will reduced the mobility and contain the toxicity of the
 contaminants at the Site.  In addition the selected alternative is protective of human health and the
 environment, will attain federal and state ARARs, is cost effective, and utilizes permanent
 solutions to the maximum extent practicable. The estimated  present worth cost of the selected
 remedy is $9,356,000 and will take approximately 3 years to complete.

 Actual or threatened release, if not addressed by the implementation of the response action
 selected in this ROD, may present an imminent and substantial endangerment to public health,
 welfare, or the environment.


 9.1    Major Components of the Selected Alternative

 The selected remedy includes Institutional Controls, Excavation/Consolidation, Capping, and
 Saturation Zone Source Control. Institutional Controls in the form of deed restrictions must be
 placed on the consolidation area to prevent any construction or other activity that would threaten
 the integrity of the selected remedy. A buffer zone (as determined in the Remedial Design) must
 be established around this consolidation area to limit access to this area. Since the contamination
 will be removed from the other areas of the Site and consolidated, these other areas which comply
 with the Performance Standards will not require institutional control; however, the property
 owner may voluntarily place deed restrictions or land use restrictions on the Site property. Site
 fences and security must be maintained at an adequate level to ensure the security of the Site and
 its remedy.  The surface water must be monitored to ensure the source control remedy continues
 to be effective.   All waste material and soil that exceeds any of the Performance Standards for
 the Site (Table 9-2) must be excavated and consolidated in the several consolidation areas.  One
 of the possible consolidation areas includes the areas where the clarifier is found, the water tower
 area, the power house area, and the area where Ponds 44 through 51 are located..

 This is the first of two operable units planned for the Site. This action addresses the source of the
 soil contamination by treating and containing the source material.

 The major components of the selected remedy include:  •


 •      Excavation of radiologically and chemically contaminated material/soil  which exceed
       Residential Cleanup Standards.

•      Consolidation of the radiologically and chemically contaminated material/soil in the main

                                   Page  56  of   61

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                                                                            5   9      0064
        pond area. A Top Cover Cap which meets Florida's FAC 62-701.050 must be placed
        over the Consolidation Area.
  •     Institutional Controls must be placed on the Site.  Institutional controls must include deed
        restrictions, land use ordinances, physical barriers, and water supply well permitting
        prohibitions. These restrictions will limit access to the Site and prohibit the disturbance of
        the remedy.

  •     Source Control will require the Insitu Solidification/ Stabilization of pond material and
        contaminated soil below the water table.

 The total present worth cost for the selected remedy as presented in the feasibility study is
 $9,356,000.
 9.2    Performance Standards

 The performance standards for source remediation are based on the protection of the ground
 water and/or protection of human health (Table 9-1 - Performance Standards: Remedial
 Goals). The entire Site is considered an Area of Concern and a Corrective Action Management
 Unit under the Resource, Conservation, and Recovery Act (RCRA).

        9.2.1  Performance Standards - Cap

 The selected remedy must adhere to the FDEP Land Disposal Requirements which are presented
 in FAC 62-70] .050. FDEP requires that unlined landfills specify a final cover consisting of a final
 18-inch thick layer of soil that will sustain vegetation to control erosion and placed on top of a
 barrier layer which has a permeability of 1 x 10"' or less.
       9.2.2  Performance Standards - Solidification

The Solidification Stabilization must utilize an binding mixture that meets the following criteria: a
compressive strength of 100 psi, a permeability equal to 1 x 10"*, pass the Toxicity Characteristic
Leaching Procedure (TCLP) Test for Arsenic, and pass the SPLP Test for Arsenic. All design
specifications will be will be developed through the remedial design process as to achieve
performance standards.
       9.2.3   Performance Standards - Design

The design and construction of the selected remedy must be conducted in accordance with all
ARARs, including the RCRA requirements set forth in 40 CFR. Part 264 (Subpart F), 40 CFR
Part 268, and 40 CFR Part 264. See table 8-1, 8-2, and 8-3 for a detailed description of the
Performance Standards which are listed as ARARs.

                                  Page 57 of   61

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                                                                            5   9       0065
                                        Table 9-1
                          Performance Standards: Remedial Goals
Soil/Waste Contaminant
Arsenic
Antimony
Beryllium
Elemental Phosphorus
Thallium
Radium-226 (Lead-210)*
Total CPAHs **
Maximum Concentration
Detected (mg/kg)
127
32.3
1.6
0.854
13.4
73.8 pCi/g
-
Remedial Cleanup Goals
(mg/kg)
#
28.1
0.192
1.4
1.4
5pCi/g
0.089
        *   Note that this cleanup level is measured above the background (normal)
              concentration. The background (normal) concentration will be established during
              the Remedial Design.

        **  Total CPAHs include Benzo(a)anthracene, Benzo(a)pyrene, Benzo(b)fluoranthene,
             Dibenzo(a,h)anthracene, and Indeno(l,2,3-cd)pyrene.

        #     EPA Region 4 regulates arsenic in soil as a systemic toxicant with a reference dose
              of 0.0003 mg/kg/day. The safe soil level for residential use that would not exceed
              this RfD for a child was determined in the Site's risk assessment to be 21.1 mg/kg.
              EPA also considers arsenic to be a carcinogen in the form that may occur in
              drinking water and has included an oral slope factor in its IRIS database. The
              application of the slope factor here, though not considered appropriate, would
              yield a calculated safe soil level for a child at the most protective 10"* risk level of
              0.46 mg/kg.  The latter soil cleanup level for arsenic is likely to be achieved since
              soil containing arsenic above this level also contains other contaminants that will
              require remediation.

The Remedial Goals have been derived from the Final Baseline Risk Assessment with the
exception of Radium-226 which has been establish in accordance with the relevant and
appropriate requirement (Federal Standards  for the Cleanup of Land and Buildings Contaminated
with Residua] Radioactive Material 40 CFR  192).
                                  Page  58  of   61

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                                                                          5   9      0066
 9.3    Compliance Testing
 Surface water monitoring will be conducted at the Site.  After the remedy has been completed the
 Site will be evaluated and samples will be collected to verify that Site soil have been remediated.
 Site soil outside of the consolidation area must meet the Performance Standards (Table 9-1). The
 exact locations and sampling plan will be outlined in the Remedial Design/Remedial Action. If
 monitoring indicates that the remedy is no longer effective or the Site contamination is being
 released into the surface water additional remedial action measures may be required.
 10.0  STATUTORY DETERMINATION

 Under Section 121 of CERCLA, 42 USC 9621, EPA must select remedies that are protective of
 human health and the environment, comply with applicable or relevant and appropriate
 requirements (unless a statutory waiver is justified), are cost effective, and utilize permanent
 solutions or permanent treatment technologies or resource recovery technologies to the maximum
 extent practicable. In addition, CERCLA includes a preference for remedies that employ
 treatment that permanently and significantly reduces the volume, toxicity or mobility of hazardous
 waste as their principle element.  The following sections discuss how the selected remedy meets
 these statutory requirements.
 10.1   Protection of Human Health and the Environment

 The selected remedy provides protection of human health and the environment by eliminating
 reducing, and controlling the risks through engineering controls and/or institutional controls and
 soil treatment as delineated through the performance standards described in Section 9.0 -
 SUMMARY OF THE SELECTED REMEDY. The residual risk due to individual
 contaminants will be reduced to a probability of 1 x 10"* for carcinogens and a hazard Quotient of
 1 for non-carcinogens. The residual carcinogenic risk at the Site, which is the sum of individual
 carcinogenic risks, will be reduced to acceptable levels (i.e., cancer risks between  1 x 10"* and 1 x
 lO^once performance standards are achieved.  The implementation of this remedy will not pose
 an unacceptable Short-Term risks or cross media impact.
10.2   Attainment of Applicable or Relevant and Appropriate Requirements f ARARs)

Remedial actions performed under Section 121 of CERCLA, 24 USC. 9621, must comply with
all applicable or relevant and appropriate requirements (ARARs). All alternatives considered
were evaluated on the basis of the degree to which they complied with these requirements. The
selected remedy was found to meet ARARs identified in Table 8-1 through 8-3. The following is
a short narrative explaining the attainment of relevant ARARs.
                                 Page 59  of   61

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                                                                           5   9       0067
 Chemical-Specific ARARs
 Performance Standards are consistent with the ARARs identified in Table 8-3.

 Action-Specific ARARs
 Performance Standards are consistent with the ARARs identified in Table 8-2.

 Location-Specific ARARs
 Performance Standards are consistent with the ARARs identified in Table 8-1.

 The selected remedy is protective of species listed as endangered or threatened under the
 Endangered Species Act.  The requirements of the Interagency Section 7 Consultation Process
 b50 CFR Part 402, will be met.  The Department of Interior, Fish and Wildlife Services, will be
 consulted during the Remedial Design to ensure that the endangered and threatened species are
 not adversely impacted by the implementation of the remedy.

 Waivers
 Waivers are not anticipated at this Site at this time.
 10.3   Cost Effectiveness

 After evaluating all alternatives which satisfy the two threshold criteria, protection of human
 health and the environment and attainment of ARARs, EPA has concluded that the selected
 remedy, Alternative 5b affords the highest level of overall effectiveness proportional to its cost.
 Section 300.430(1 )(ii)(D) of the NCP also requires EPA to evaluate three out of five balancing
 criteria to determine the overall effectiveness: long-term effectiveness and permanence; reduction
 of mobility,  toxicity, or volume through treatment and short-term effectiveness.  Overall
 effectiveness is then compared to cost to ensure that the remedy is cost-effective. The selected
 remedy provides for overall effectiveness proportional to its cost.

 The selected remedy has a moderate present worth, capital, and operation and maintenance cost
 compared to other remedies, and best satisfies the criteria for long-term effectiveness and
 permanence and short-term effectiveness.  This alternative will reduce toxicity, mobility, or
 volume through treatment.

 The estimated present worth costs for the soil/source selected remedy is $9,356,000.

 10.4   Utilization of Permanent Solution to the Maximum extent Practicable

EPA has determined that the selected remedy represents the maximum extent to which permanent
solutions and treatment technologies can be utilized in a cost-effective manner for the final
remediation  at the Site.  Of those alternatives that are protective of human health and the
environment and comply with the ARARs, EPA has determined that Alternative 5b provides the
best balance of trade-offs in terms of long-term effectiveness and permanence, reduction of
toxicity, mobility, or volume achieved through treatment, short-term effectiveness,
implementability, and cost, while also considering the statutory preference for treatment.

                                  Page  60  of  61

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                                                                                     OC68
 10.5   Preference for Treatment as a Principal Element

 The statutory preference for treatment is satisfied by the selected remedy.


 11.0   DOCUMENTATION OF SIGNIFICANT CHANGES

 Two significant differences have been added to the selected remedy, Alternative 5b, from the
 preferred remedy described in the proposed plan. The addition of Asbestos to the list of Potential
 Contaminants of Concern is the first significant difference from the proposed plan. This change
 was necessitated by the detection of Asbestos on-Site. The second  significant difference allows
 for flexibility in the design and construction of consolidation areas.  The ROD permits the creation
of one or more than one consolidation areas on-Site. The actual determination will be presented
and documented in the Final Remedial Design.
                                Page  61  of   61

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                            5  9    0069
Responsiveness Summary




     Appendix A

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                                                                                     P, •"> o
5   9       0070
                            Responsiveness Summary
 The U.S. Environmental Protection Agency (EPA) originally established a public comment period
 from May 29, 1996, through August 29, 1996 in order to allow the public an opportunity to
 comment on the Proposed Plan for Operable Unit One for the Stauffer Chemical Company,
 Tarpon Springs, Superfund Site (Site). At the request of Pi-Pa-Tag (the Technical Assistance
 Grant Group set up to aid the community), the public comment period was extended through
 September 16, 1996. The comment period followed a public meeting held on May 29, 1996 at
 the Gulfside Elementary School.  At the public meeting, EPA presented the Proposed Plan for
 Remedial Action for the Site for Operable Unit One. The meeting presented the results of the
 studies undertaken and the preferred remedial alternative for Operable Unit One for the Site

 This Responsiveness Summary provides a summary of the citizens comments and concerns as
 raised during the comment period. Public comments are specifically addressed through EPA
 responses. All comments summarized by this document have been factored into the final decision
 for the cleanup of the Site.

 This responsiveness summary for the Stauffer Chemical/Tarpon Springs Site is divided into the   .
 following sections:

       I.      Overview This section discusses the recommended alternative for remedial
              action and the public response to this alternative.

       II.    Background on Community Involvement and Concerns.  This section
             provides a brief history of community interest and concerns regarding the
             Site.

       III.    Summary of the Major Questions and Comments Received During the
             Public Comment Period This section presents written comments submitted
             during the public comment period, and provides responses to these
             comments.

       IV.    Remaining Concerns This section discusses community concerns that EPA
             should be aware of in design and implementation of the remedial action
             alternative for the Site.

I.      Overview

The preferred remedial alternative was presented to the public in a fact sheet released April 29,
1996, and presented to the public at the proposed plan public meeting on May 29, 1996. The


                                    Page 1 of 8

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                                                                        59      0071
 recommended alternative addresses the source of the contamination by excavating the
 contaminated material, consolidating it, solidifying the material that is below the water table, and
 capping the contaminated material.

 In general, the community favors the selection of the recommended alternative.  However, the
 community is concerned about the height of the mound containing the consolidated material.
 Some community members recommended that the waste be sent off-site to a disposal facility.

 II.     Background on Community Involvement

 The Tarpon Springs community has been aware of the contamination at the Site for several years.
 The Site operated in this community from 1947 through its shutdown in 1987.  The first fact sheet
 was distributed to the community by EPA in March 1993. A total of four public meeting have
 been held by EPA to solicit public input in the decision-making process. Interviews have been
 conducted with members of the Tarpon Springs community.

 At the fourth public meeting, on May 29, 1996, the recommended alternative was presented to the
 community. Sampling results, the Remedial Investigation, the Feasibility Study, and alternatives
 for the cleanup were discussed at this meeting. EPA answered specific questions and informed
 the public that their comments will be addressed in the responsiveness summary.

 At the meeting the key issues and concerns were as follows:

 •     Off-site Disposal of Contaminated Material. Many of the residents of the surrounding
       community recommended that EPA excavate and transport all contaminated material to a
       an off-Site landfill. Many of these citizens voiced their opinion that the hazardous waste
       should be dug up and transported out of their community.

 •     Cap the Contaminated Material.  Meyer's Cove residents recommended that EPA not
       move the contaminated material, but only cover it in place. These residents are very
       concerned that the contamination will become airborne. Some residents expressed
       concern about the proposed location of the consolidated zone and the height of the
       resulting mound of consolidated material.

 ffl.    Summary of the Major Questions and Comments Received During the
       Public Comment Period

 Thirty-six letters were received during the extended comment period, including two letters that
 requested an extension to the comment period. Many of the comments and suggestions were the
 same although they were sent by different individuals or groups. These duplicated comments will
be addressed only once in this summary.  Topics relevant to the selected remedy are addressed in
this summary. Comments related to the Remedial Design phase of the Superfund process will be
addressed when the Remedial Design documents are written, finalized, and approved.


                                     Page 2 of 8

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                                                                             _       ^% »^» *~y ,-\
                                                                         5   9       Ou/2
 Comment #1: Several comments stressed that the material should not be moved.  They stated
              that it should be left in place and "not disturbed".

 EPA Response #1:    One of the nine balancing criteria used to evaluate the selected remedy is
                     the Reduction in Toxicity, Mobility, or Volume through Treatment.
                     The consolidation and solidification/stabilization is needed to fulfill this
                     requirement. To address the communities concern, EPA has modified the
                     remedy proposed in the Proposed Plan by creating more than one
                     consolidation area. By making this change, the movement of hazardous
                     substances is kept to a minimum.  Some movement  of hazardous
                     substances will be necessary to bring the Site from an uncontrolled state to
                     a controlled state.

 Comment #2: Several letters expressed concerns about the health and welfare of the children,
              faculty, and staff at Gulfside Elementary School.

 EPA Response #2:   Every practical precaution will be taken to ensure the safety of the children,
                    faculty and staff at the elementary school. Also, precautions will be taken
                    to protect the surrounding residents.

 Comment #3:  Many of the comments received during the public comment period were related to
              the Remedial Design (top cover design, engineering controls, real-time air
              monitoring, siren/alarm, dust suppression, etc.).

 EPA Response #3:   EPA will address all issues that pertain to the Remedial Design during the
                    next phase of the Superfund process. Design details and specifications will
                    be presented in the Final Remedial Design.

Comment #4:  A number of letters commented that EPA should remove the hazardous material
              from the Site either by sea, by rail, or by truck.

EPA Response #4:    As presented previously in the feasibility study, off-site disposal was
                    eliminated through the screening process. First, the  excavation and
                    removal of all contaminated hazardous substances would not be protective
                    of human health and the environment. In fact due to the presence of
                    elemental phosphorus and radium-226 which is air reactive, the excavation
                    of all hazardous substances and contaminated soil would create an even
                    greater hazard than the one that currently exists at the Site. Contaminated
                    substances would have a greater opportunity to be released to the
                    atmosphere.  Second, the cost as documented in the  feasibility study make
                    the option impractical (the low cost estimate = S200 Million and the high
                    cost estimate - $1.6 Million). Third, the truck traffic would be extremely
                    high (15,000 trucks per year). Fourth, transportation by rail and by truck


                                      Page 3 of 8

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                                                                         5   9
                     would unnecessarily expose or potentially expose residences in Tarpon
                     Springs and other communities to hazardous substances. Finally, after
                     considering all of these factor, EPA views the off-site alternative as
                     inappropriate and unsafe. EPA rejects this alternative.

 Comment #5: A few comments mentioned the fact that EPA's decision was based on old
              demographic data.  Also, many commented that they felt that residential cleanup  /
              standards should be used.

 EPA Response #5:    EPA has made the decision to use residential cleanup standards which are
                     the most conservative available.  The fact that EPA is using the most
                     stringent standards possible makes the question of demographics irrelevant.

 Comment #6: A few groups asked EPA to extend the public comment period.

 EPA Response #6:    EPA granted an extension from August 29,  1996. until September 16,
                     1996.

 Comment #7: Several people commented that the height and the aesthetics of the consolidation
              area were unacceptable.

 EPA Response #7:   In an effort to provide flexibility in the design and to minimize the release
                    of hazardous substances to the environment, EPA has added flexibility to
                    the ROD to allow more than one consolidation area to be created. A final
                    decision concerning the number of consolidation areas will be decided
                    during the Remedial Design phase.

 Comment #8:  A few comments were made concerning the groundwater (the surficial and the
              Floridan aquifers).

 EPA Response #8:    Since groundwater will not be addressed by this operable unit, comments
                    concerning the groundwater will be addressed in a subsequent (second)
                    Record of Decision.

 Comment #9: One person commented that the consolidation area may collapse into the Floridan
             Aquifer.

EPA Response #9:    The hydro-geologic studies that have been performed do not indicate that
                    this is a likely outcome.  On the contrary, the semi-confining layer should
                    support the consolidation areas proposed for the Site. There is no evidence
                    that the consolidation areas will created an unnecessary burden  on the
                    confining layer.
                                      Page 4 of 8

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                                                                       5   9
                                                                                      .-> ft ,.
                                                                                      u / 4
 Comment #10:
 EPA Response #10:
 Comment
 EPA Response #11
                     A few residents of Myers Cove wrote and expressed concern about how
                     the remediation would affect their property and their health.

                     EPA will make every effort to ensure the safety of the Meyers Cove
                     residents. Engineering controls will be specified in the Remedial Design.

                     One person commented that she was concerned that the Site may have
                     been used for military exercises.

                     The fact that the Site may have been used for military exercises is not
                     relevant to the cleanup of the Site. The investigation conducted for this
                     Site was comprehensive and was independent of any biases. The
                     contamination that exists has been documented by collecting samples using
                     the full  scan of constituents.

                     One letter received during the comment period commented that a building
                     moratorium should be placed on the property and permits in the area
                     should be restricted.

                     Deed restrictions will be placed on the property once the Remedial  Action
                     has been completed.?- Permits and zoning are under the jurisdiction of the
                     county and other local government agencies.

                     One person stated that he was concerned that the Potentially Responsible
                     Party (PRP) was monitoring the Site as opposed to EPA monitoring the
                     Site.  He suggested that EPA take a  more active role in monitoring  the
                     Site.

                    EPA has collected samples in all media at the Site, and EPA collected split
                    samples during the Remedial Investigation.  The nature and extent of
                    contamination at the Site is well known and well documented. EPA will
                    continue to monitor the situation and if conditions change appropriate
                    actions will be taken.

                    One letter commented that the 1x10"* risk level should not be used at the
                    Site. The letter also included several  attachments supporting this statement.
                    The letter asked EPA to consider utilizing a commercial/industrial scenario
                    and cleaning to the 1 x 10*4 risk level.

EPA Response #14:   EPA views the risk level of 1 x 10* as appropriate. The proximity of the
                    elementary school and other sensitive populations must be protected.
 Comment #12:
EPA Response #12:
Comment #13:
EPA Response #13:
Comment #14:
                                     Page 5 of 8

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                                                                         5   9
                                                                    0;^ «T
                                                                    u/
 Comment #15:


 EPA Response #15.•


 Comment #16:


 EPA Response #16:



 Comment #17:


 EPA Response #17:
 Comment #18:
 One letter suggested several action levels for different chemicals of
 concern.

 EPA considered all suggestions; however, no changes were recommended
 by the EPA which are less stringent than the 1 x 10* risk level.

 One group asked where the slag material generated at the Site was
 transported?

 Some slag material remains on-Site and will be consolidated with other
 contaminated materials. EPA is currently investigating the off-Site
 locations where the Stauffer material may have been deposited.

 One group stated that there has never been a health survey to determine
 how many people were affected by this Site.

 The Agency for Toxic Substance and Disease Registry (ATSDR) is the
 agency that addresses health related issues. ATSDR has begun the
 notification process.  The notification process included contacting the
 former employees of the Site and informing them that the Site is on the
 National Priorities List.

 Another group asked - Can it be guaranteed without a shadow of a doubt
 that no contamination exists on the areas not included in the remediation
 plans including the groundwater beneath them?
EPA Response #18:  Although EPA does not provide guarantees, EPA has conducted extensive
                    sampling of soil and groundwater. EPA will outline specific plans to
                    cleanup the soil within the RD. Remediation of the groundwater will be
                    handled through a separate ROD (Operable Unit 2).
Comment #19:
Another group asked - What has been the experience of dealing with
similar phosphate site? Where are these sites and how have they been
cleaned up?
EPA Response #19:  EPA Region 4 has consulted with other Region's that have handled similar
                    phosphate sites and has considered the information received in formulating
                    cleanup options for this Site. However, it is EPA's policy not to directly
                    compare one site to another, but instead to judge each site on a site-
                    specific basis using the Nine Criteria evaluation method as specified by the
                    National Contingency Plan, 40 CFR 300.430.
Comment #20:
Another question asked - What will be the effect of the proposed
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                                                                          5  9      CG76
 EPA Response #21:
 Comment #21:
 EPA Response #21;
 Comment #22:
 desalination plant on this Site?

 The construction and operation of a desalination plant should have no
 effect on the remediation of the Site, and the remediation of the Site should
 have no effect on the plant.

 One comment stated that there was a large pit that was used for disposal.
 The group wanted to know - what will be done to this area?

 This comment is ambiguous and unclear as to where the "pit" is located. If
 the intent of the comment was to ask about a pit on-Site, then it will be
 cleaned up and addressed during the Remedial Action at the Site.  If the
 comment was directed towards an area off-Site, further investigation would
 be necessary. All disposal areas on-Site will be addressed as part of the
 Remedial Action.

 Another person asked - How will the horizontal movement of the
 contaminated water be dealt with when solidification is carried out?
 EPA Response #22:  By eliminating the source of contamination by solidifying it in a matrix that
                    has a low permeability, the volume of contaminated groundwater will
                    decrease. Groundwater will be specifically addressed in the next operable
                    unit ROD.
Comment #23:
EPA Response #23:
Comment #24:
Another group wanted to know - How many sites did Stauffer pollute?

To ascertain information about other sites that Stauffer Management
Company (SMC) owns, SMC has been contacted. The answer to this
question will be made available to the public.

A group asked - Have you contacted the union in order to contact former
employees of Stauffer?
EPA Response #24:  Health related issues are addressed by ATSDR.

Comment #25:       Another asked - Who will carry out the Five Year Review?
EPA Response #25:
Five year reviews will be necessary for this Site because contamination will
be left on Site above levels that allow for unlimited use and unrestricted
exposure. EPA will compile the documentation for the Five Year reviews.
It is too early in the process to predict who will collect samples.
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 Comment #26:
 EPA Response #26:
Comment #27:
EPA Response #27:
                                                    5  9      O

Another question asked - Who will decide who will perform the
remediation work?

This question will be determined once the Consent Decree negotiations for
the Remedial Design/Remedial Action are completed. If a Potentially
Responsible Party (PRP) signs the Consent Decree, then the PRP will
conduct the RD/RA with EPA oversight.

Finally, one group asked - Since it appears that many questions cannot be
answered before the RD, how can the best option be chosen?

Many of the questions posed to EPA can only be answered when the final
RD is written and approved. As stated earlier, the nine criteria
comparative analysis was used to  evaluate cleanup alternatives.
IV.    Remaining Concerns

EPA believes that all relevant issues that have been raised are addressed in this responsiveness
summary.
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