EA-0976; Environmental Assessment and (FONSI) of Corrective Action at the Northeast Site

                                                               DOE/EA-0976
          Environmental Restoration Program
          ENVIRONMENTAL ASSESSMENT OF CORRECTIVE
          ACTION AT THE NORTHEAST SITE
          PINELLAS PLANT
          LARGO, FLORIDA
          February 1995
          Draft
          Prepared by:
          U.S. Department of Energy
          Albuquerque Operations Office
          With the technical assistance of:
          Environmental Restoration Program
          Technical Support Office
          Los Alamos National Laboratory

ACRONYMS

      AQI             Air Quality Index
      CEC             cation exchange capacity
      CERCLA          Comprehensive Environmental Response, Compensation and Liability Act
      CFR             Code of Federal Regulations
      CMA             corrective measure alternative
      CMS             corrective measure study
      COC             contaminant of concern
      DOE             U.S. Department of Energy
      EA              environmental assessment
      EPA             U.S. Environmental Protection Agency
      EPI             Emergency Prediction Information (model)
      FDEP            Florida Department of Environmental Protection
      FWS             Fish and Wildlife Service
      HSWA            Hazardous and Solid Waste Amendments
      ISC             Industrial Source Complex
      MCL             maximum contaminant level
      MCS             media cleanup standard
      MSL             mean sea level
      NAAQS           National Ambient Air Quality Standards
      NEPA            National Environmental Policy Act
      NTL             no-threat level
      PCAQD           Pinellas County Department of Environmental Management Air Quality Division
      PVC             polyvinyl chloride
      RCRA            Resource Conservation and Recoverv Act
      RFl             RCRA facility investigation
      SDWA            Safe Drinking Water Act
      SSC             species of special concern
      SVOC            semivolatile organic compound
      SWCFGWB         Southern West-Central Florida Groundwater Basin
      SWMU            solid waste management unit
      TLV-C           threshold limit value-ceiling
      TLV-TWA         threshold limit valuee-time-weighted average
      USGS            U.S Geological Survey
      UV              ultraviolet
      VOC             volatile organic compound

1. BACKGROUND

1.1. INTRODUCTION

The National Environmental Policy Act (NEPA) requires federal agencies to assess the
impacts that major federal actions may have on the quality of the human environment.
The U.S. Department of Energy (DOE) procedures for implementing the NEPA are
contained in the Code of Federal Regulations (CFR), Title 10, Part 1021 (10 CFR
1021) and DOE Order 5440.1E.
This document constitutes an environmental assessment (EA) of the proposed corrective
action for the Northeast Site at the DOE Pinellas Plant (Figure 1.1). It examines
the short- and long-term environmental effects of the proposed corrective action and
the reasonable alternatives. The information and analyses presented here will be
used to determine whether the proposed corrective action would have a significant
impact on the environment. If the impact is determined to be significant, an
environmental impact statement will be prepared for the proposed corrective action.
If the impact is judged not to be significant, a Finding of No Significant Impact
will be issued, and the proposed corrective action will be implemented. These
procedures and documents are defined in regulations issued by the Council on
Environmental Quality in 40 CFR 1500 through 1508, as well as in 10 CFR 1021.
Section 1 of this EA describes the Pinellas Plant and the Northeast Site, and Section
2 states the need for the DOE action. Section 3 describes the proposed corrective
action and the reasonable alternatives to it. Section 4 describes the present
condition of the environment, and Section 5 assesses the environmental impacts of
the proposed corrective action and the reasonable alternatives. This EA does not
contain all of the details of the studies on which it is based. The details are
contained in the referenced supporting documents.

1.2. PINELLAS PLANT

The Pinellas Plant (Figure 1.1) is on approximately 99 acres in Section 13, Township
30 South, Range 15 East (Tallahassee Meridian), in the center of Pinellas County,
Florida (Latitude 27 52' 30" North, Longitude 82 45' 00" West). The city of Tampa is
approximately 20 miles east of the Pinellas Plant, and the city of St. Petersburg is
about 6 miles to the south. Building 100 (Figure 1.2) is the most notable feature of
the Pinellas Plant and houses the DOE Pinellas Area Office and most of the plant
laboratory and production facilities. Numerous other structures function as storage,
utility, and testing facilities throughout the plant.
Figure (Page 1-2)
Figure 1.1 Pinellas Plant Location.
Figure (Page 1-3)
Figure 1.2 Pinellas Plant Site Map.
Figure (Page 1-3)
Figure 1.2 Pinellas Plant Site Map.
The Pinellas Plant is a government-owned facility that is administered by the DOE
Albuquerque Operations Office and operated by a DOE contractor. The plant was
constructed in 1956 and 1957 as part of the nuclear weapons production complex, and
the original products of the plant were neutron generators, a principal component of
nuclear weapons. The production of these devices required the development of several
uniquely specialized areas of competence and supporting facilities which led to the
manufacture of other weapons application products. The plant also maintains the
capability for applied research that is necessary for the manufacture of plant
products. In 1993, the DOE decided to phase out the Pinellas Plant and has proposed
leasing all or portions of the plant to commercial enterprises. It is anticipated
that the commercial enterprises would involve manufacturing processes identical or
similar to the processes currently used at the Pinellas Plant (DOE 1994d).
The types of waste generated at the Pinellas Plant have been fairly consistent
throughout the plant's history. Solid, liquid, and gaseous wastes generated at the
plant are both radioactive and nonradioactive. These wastes are stringently
controlled by a variety of treatment, control, and monitoring systems. Currently,
all hazardous wastes are either treated onsite to render them nonhazardous or are
shipped offsite to permitted waste treatment or disposal facilities.
Under the provisions of the Resource Conservation and Recovery Act (RCRA), as amended
by the Hazardous and Solid Waste Amendments (HSWA), the U.S. Environmental
Protection Agency (EPA) issued the Pinellas Plant a HSWA Permit in 1990 (EPA 1990a).
The HSWA Permit, in conjunction with the Hazardous Waste Management Permit issued by
the Florida Department of Environmental Protection (FDEP) (FDEP 1994), authorizes the
Pinellas Plant to operate as a hazardous waste storage and treatment facility. The
HSWA Permit also sets forth the conditions and requirements for RCRA corrective
actions at the plant. A corrective action is a measure or measures taken to protect
human health and the environment from all releases of hazardous waste or
constituents from any solid waste management unit (SWMU).
In 1988, the EPA identified 14 SWMUs at the Pinellas Plant (PIN02 through PIN15 on
Figure 1.2) (EPA 1988a), and the DOE identified an additional SWMU (PIN16 on Figure
1.2) in 1990 (DOE 1990c). To satisfy the requirements of the HSWA Permit, an RCRA
facility investigation (RFI) was completed in 1991 to address contaminant releases
and environmental conditions at the 15 SWMUs (DOE 1991b; 1992a; 1993b). The EPA
concurred with the DOE's recommendations that 11 of the SWMUs did not require any
further action because they did not present a threat to human health and the
environment. The EPA also concurred that corrective measures studies (CMSs) would be
conducted for the remaining four SWMUs (Hammond 1992). Three of these SWMUs are the
Northeast Site, Building 100 Industrial Drain Leaks, and Old Drum Storage Site, all
of which have contaminated groundwater in the surficial aquifer. The fourth SWMU, the
Pistol Range, had lead contamination in surface soils which has been cleaned up. In
1993, the DOE identified another SWMU at the Pinellas Plant (PIN17 on Figure 1.2)
(DOE 1993a). This SWMU, the West Fenceline Area, also has contaminated groundwater
in the surficial aquifer, and the EPA has concurred with the DOE's recommendation
that a CMS be conducted (DOE 1993e; Franzmathes 1993).

1.3. NORTHEAST SITE

EPA Region IV has designated the Northeast Site (approximately 20 acres) to include
all of the northeast section of the Pinellas Plant located within the perimeter
fence and bounded by the Spray Irrigation Site on the west and a parking lot to the
south (Figure 1.2). The concerns with the Northeast Site are the former drum storage
and disposal activities conducted at the site and the past discharge of industrial
waste to the East Pond (DOE 1991b).
The East Pond was constructed in 1968 next to a naturally swampy area. The East Pond
was deepened in late 1972, and the removed soil was used to cover the swampy area
and reportedly to build the backstop at the former Pistol Range. The East Pond
currently has a capacity of 3.25 million gallons (CH2M Hill 1987). From 1968 until
1972, the East Pond received storm water runoff and pH-neutralized wastewater; in
1972, the industrial wastewater was redirected to the West Pond. Liquid waste from
the West Pond was discharged through a spray irrigation system that was equipped with
a drainage system for intercepting infiltrating water and diverting it to the East
Pond. These operations continued until 1982 when the spray irrigation system was
abandoned. The East Pond currently receives only storm water runoff from the area
between the Northeast Site and Building 100 and is connected through a closed
underground piping system to the South Pond (DOE 1987). East Pond overflow
discharges through a county drainage pipe, south along Belcher Road, and then east
along Bryan Dairy Road until it empties into a county drainage ditch. Flow continues
southward, entering Cross Bayou Canal, Cross Bayou, and finally Boca Ciega Bay
(Figure 1.1). For an undetermined period of time between 1968 and 1972, the East
Pond discharge reportedly flowed north along Belcher Road; Pinellas County rerouted
the flow south when the area north of the Pinellas Plant became residential (DOE
1991b).
Before 1968, the naturally swampy area west of the East Pond was used as a staging
area for drums of waste solvents and construction debris. All of the waste drums
were to have been removed when the East Pond was constructed. However, three drums
buried near the East Pond were found in October 1984. Two of these drums were empty,
and one drum contained construction debris and rebar (DOE 1987). Partially due to
this discovery, investigations of the Northeast Site and East Pond were conducted in
1985 and 1987 (Fernandez 1985; DOE 1987; CH2M Hill 1987). These investigations
consisted of electromagnetic surveys, trenching, soil sampling, test borings,
monitoring well installation, groundwater sampling of new and existing monitoring
wells, and surface water sampling of the East Pond. A VOC groundwater plume was
identified west of the East Pond.
The RFI (DOE 1991b) confirmed that surficial aquifer groundwater in Northeast Site
monitoring wells contained concentrations of VOCs and SVOCs that exceeded Safe
Drinking Water Act (SDWA) maximum contaminant levels (MCLs) and FDEP drinking water
standards. The RFI also indicated the presence of mercury in the East Pond. The
potential contaminants of concern (COCs) in groundwater were identified as
dichloromethane (methylene chloride), 1,2-trans-dichloroethene, benzene,
4-methylphenol (p-cresol), trichloroethene, chloroethene (vinyl chloride), and
phenol. Therefore, the DOE recommended, and the EPA concurred (Hammond 1992), that a
CMS of the surficial aquifer groundwater and surface water pathways be conducted for
the Northeast Site. The CMS for the Northeast Site (DOE 1993c; 1993d; 1994b)
identified corrective action objectives and screened corrective measure technologies
that would meet those objectives. Corrective measure technologies that were found to
be feasible were then combined to form corrective measure alternatives (CMAs), which
were evaluated against technical, environmental, human health, and institutional
criteria as required by the HSWA Permit. The CMS resulted in a recommendation that
pump and treat with air stripping be implemented as the corrective action for the
contaminated surficial aquifer groundwater at the Northeast Site. Implementation of
the proposed corrective action for the Northeast Site is pending regulatory approval
by the EPA and FDEP.
Additional groundwater sampling was performed for the CMS. The concentrations of
contaminants in CMS groundwater samples were generally higher than those measured in
the RFI samples, and two distinct contaminant plumes were identified in the surficial
aquifer. The two separate contaminant plumes are just west of the northern and
southern portions of the East Pond, and the vertical extent of the contamination is
from approximately 16 to 26 ft below the ground surface. Low concentrations of
contaminants were also detected in monitoring wells along the eastern boundary of the
Pinellas Plant. For the purpose of this EA, the two contaminant plumes in the
surficial aquifer were considered to be one, as shown in Figure 1.3 (DOE 1993b).
Surface water samples taken from the East Pond during the RFI contained mercury
concentrations slightly above the SDWA MCL and FDEP drinking water standard (DOE
1991b). Supplemental RFI sampling of surface water in the East Pond was approved by
the EPA (Hammond 1992; Ingle 1992a,b), and was conducted to confirm or refute the
presence of mercury. This sampling indicated that mercury was not present above the
SDWA MCL and FDEP drinking water standard. Mercury is, therefore, no longer
considered to be a potential COC for the Northeast Site, and the CMS Report
recommends that the surface water pathway be deleted from the CMS for the Northeast
Site. The CMS also resulted in a recommendation that phenol be eliminated as a COC
because phenol does not have an appreciable influence on human health risks (DOE
1993c). Soil and sediment sampling did not identify any COCs for these media, and the
RFI Report concluded that no measurable contaminant mass remained in the vadose zone
at the Northeast Site (DOE 1991b).
Figure (Page 1-7)
Figure 1.3 Extent of Groundwater contamination at the Northeast Site (June 1992)
Figure (Page 1-7)
Figure 1.3 Extent of Groundwater contamination at the Northeast Site (June 1992)

1.4. CORRECTIVE ACTIONS

As stated in subsection 1.2, four SWMUs at the Pinellas Plant have contaminated
groundwater in the surficial aquifer. These SWMUs are the Northeast Site, Building
100 Industrial Drain Leaks, Old Drum Storage Site, and the West Fenceline Area
(Figure 1.2). In addition, there is contaminated surficial aquifer groundwater at
the 4.5-Acre Site, which is just outside the northwest corner of the Pinellas Plant
(Figure 1.2). Corrective actions are either ongoing or proposed for these SWMUs and
the 4.5-Acre Site, and all of the corrective actions together could have cumulative
environmental impacts (e.g., the withdrawal of groundwater from the surficial
aquifer).
After the 1987 investigation of the Northeast Site (CH2M Hill 1987), a preliminary
CMS (CH2M Hill 1989b) was prepared in 1989 as an internal document until the RFI
process was completed. Efforts associated with this preliminary CMS were concerned
primarily with groundwater conditions in the surficial aquifer west of the East Pond
and with the surface water quality of the East Pond. In 1991, an interim CMS (CH2M
Hill 1991) was prepared for the Northeast Site in response to concern that the areal
extent of the contaminant plume was potentially increasing and could migrate
offsite. This CMS recommended a groundwater recovery system consisting of four
recovery wells, use of an existing water treatment facility, discharge of treated
groundwater to the Pinellas County Sewer System, and a groundwater monitoring system
as an interim corrective measure for the Northeast Site. A review of the interim
groundwater recovery system resulted in a determination that the system was
categorically excluded from further NEPA review and documentation (i.e., did not
require the preparation of an EA or an environmental impact statement), and the
system was installed in January 1992.
The four recovery wells for the interim groundwater recovery system were installed
west of the East Pond (Figure 1.4). Each well is 24 to 30 ft deep and cased with
polyvinylchloride (PVC) plastic. The wells were equipped with pneumatic pumps, and
contaminated groundwater from the surficial aquifer is being pumped from each well
through underground piping to a holding tank north of the wells. The contaminated
groundwater is then pumped from the holding tank through underground piping to the
4.5-Acre Site groundwater treatment facility in the northwest corner of the Pinellas
Plant (Figure 1.4). This groundwater treatment facility uses an air stripper to
remove VOCs and SVOCs from the contaminated groundwater, and the effluent from the
treatment system is pumped to the Pinellas Plant wastewater neutralization facility
for further treatment and eventual discharge with sanitary wastewater into the
Pinellas County Sewer System (CH2M Hill 1989a; DOE 1992b).
Figure (Page 1-9)
Figure 1.4
Figure (Page 1-9)
Figure 1.4
Interim corrective action for contaminated surficial aquifer groundwater is also
underway at the 4.5-Acre Site. The 4.5-Acre Site is at the northwest corner of the
Pinellas Plant (Figures 1.2 and 1.4) and was previously part of the plant. The site
was sold to a private individual in 1972, and in 1984 it was discovered that the
area had been used to bury drums of solvent and resinous waste in the 1960s. The
buried drums were removed, and an assessment of the contamination began in 1985 and
has continued to date. In 1985, three contaminated groundwater plumes were identified
at depths of 0, 10, and 30 ft; monitoring data from 1987 indicated plume migration
offsite (CH2M Hill 1991). The COCs at the 4.5-Acre Site are 1,1-dichloroethane,
1,1-dichloroethene, 1,2-trans-dichloroethene, benzene, bromodichloromethane,
dichloromethane, ethylbenzene, tetrachloroethene, toluene, trichloroethene,
trichlorofluoromethane, chloroethane, xylene, arsenic, chromium, and manganese (DOE
1992c). A contamination assessment report (S&ME 1986) and a subsequent interim
corrective action plan (S&ME 1987) were approved by the FDEP in 1988, and a
groundwater recovery and treatment system was put into operation in December 1990.
The groundwater treatment system uses an air stripper to remove the VOCs and SVOCs,
and the treated groundwater is then pumped to the Pinellas Plant wastewater
neutralization facility for final discharge into the Pinellas County Sewer System.
The groundwater treatment system for the 4.5-Acre Site currently operates at its
design water inflow capacity of 20 gallons per minute because the system is treating
contaminated groundwater from both the 4.5-Acre and Northeast Sites. The DOE
proposes to increase the treatment capacity of the system to 50 gallons per minute to
provide sufficient capacity for the final corrective action at the 4.5-Acre Site, the
interim corrective action at the Northeast Site, and other possible corrective
actions (e.g., Building 100 area). Based on past and projected performance of the
groundwater recovery and treatment system, it is estimated that the corrective
action for the 4.5-Acre Site will be completed by 1999. This ongoing corrective
action at the 4.5-Acre Site constitutes a voluntary action under the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA).
The Building 100 Industrial Drain Leaks and the Old Drum Storage Site adjacent to
Building 100 (Figure 1.2) are collectively called the Building 100 Area. Because of
the proximity and the similar groundwater contamination at these SWMUs, one CMS was
conducted for the Building 100 Area (DOE 1994a). The potential COCs at the Building
100 Area are the VOCs benzene, chloroethane, chloroethene, 1,1- dichloroethane,
1,1-dichloroethene, 1,2-dichloroethene (total), tetrachloroethene,
1,1,1-trichloroethane, and trichloroethene. The contaminants are concentrated around
the northwest corner of Building 100, but the contaminant plume has the potential to
migrate. The CMS resulted in the recommendation of groundwater recovery and
treatment as the preferred corrective action. The groundwater treatment would be
accomplished by routing the recovered groundwater to the groundwater treatment system
for the 4.5-Acre Site. The implementation of corrective action for the Building 100
Area is pending regulatory approval by the EPA and FDEP, and it is estimated that the
corrective action would be completed in 20 years.
The West Fenceline Area is a new SWMU that was identified by regular groundwater
monitoring at the plant. It is located at the western Pinellas Plant boundary west
of Building 100 (Figure 1.2). A RCRA facility assessment of the West Fenceline Area
revealed chloroethene in the surficial aquifer. The contamination is confined to an
area approximately 150 ft by 225 ft, but it was detected beyond the Pinellas Plant
boundary. The contamination may be the result of past waste disposal practices and
may be associated with a nearby former storage area (DOE 1993a). An interim
corrective measures work plan (DOE 1994c) has been prepared, and implementation of
the interim corrective action air sparging with soil vapor extraction has been
approved by the EPA and FDEP (Franzmathes 1994; Nuzie 1994; Ingle 1994). Using these
techniques, pressurized air would be injected into the saturated zone at high flow
rates to volatize the contaminant, and oxygen would be added to the air to enhance
the rate of biological degradation of organic contaminants by naturally occurring
microbes. Vapor extraction wells would be installed in the unsaturated zone to
recover the sparged vapors, which would be treated prior to discharge. If air
sparging with soil vapor extraction is not successful in removing the VOC
contamination, a groundwater recovery system could be installed at the West Fenceline
Area, and the contaminated surficial aquifer groundwater would be routed to the
groundwater treatment system for the 4.5-Acre Site.

2. PURPOSE AND NEED FOR ACTION

     The RFI (DOE 1991b; 1992a; 1993b) and subsequent investigations (DOE 1993c,d; 1994b)
     have confirmed that groundwater in the surficial aquifer at the Northeast Site is
     contaminated with VOCs and SVOCs. These contaminants pose a potential threat to human
     health and the environment. The DOE needs to manage this groundwater contamination
     in accordance with the EPA's HSWA Permit (EPA 1990a) and the FDEP's Hazardous Waste
     Management Permit (FDEP 1994).

3. CORRECTIVE ACTION ALTERNATIVES

3.1. THE PROPOSED CORRECTIVE ACTION

The proposed corrective action for the Northeast Site is pump-and-treat with air
stripping and includes the installation of a groundwater containment measure and
groundwater monitoring. The conceptual design for the proposed corrective action was
developed to satisfy the requirements of the HSWA and Hazardous Waste Management
Permits for the Pinellas Plant (EPA 1990a; FDEP 1994) and to meet the established
corrective action objectives. The design for the corrective action may be modified to
reflect technological advances or site- specific conditions. All design
modifications would be approved by the EPA and FDEP prior to implementation. Details
of the conceptual design for the proposed corrective action are provided in the CMS
Report for the Northeast Site (DOE 1993c,d; 1994b), and the major features of the
conceptual design are summarized below.
A staging area would be located at the west boundary of the Northeast Site, and a
groundwater containment measure (i.e., a slurry wall, infiltration gallery, or
shallow well injection) would be installed along the northern boundary of the
Northeast Site (Figure 3.1). This groundwater containment measure would limit the
volume of clean water recovered and would limit the recovery well capture zone to
within the Pinellas Plant property to prevent contamination migration from possible
unknown sources on adjacent properties. A slurry wall would consist of a trench keyed
into the Hawthorn Formation and filled with a soil/bentonite slurry. Almost all of
the material excavated from the slurry wall trench would be backfilled into the
trench as the soil/bentonite slurry; any excavation material remaining would be used
to cover the slurry wall and restore the disturbed area along the slurry wall. An
infiltration gallery or shallow well injection would consist of perforated PVC pipe
buried a certain distance below the ground surface or a line of shallow injection
wells along the northern boundary of the Northeast Site, respectively. Treated
groundwater from the proposed corrective action would be recirculated into the
surficial aquifer through the infiltration gallery or shallow well injection. For
the purpose of this EA, a slurry wall was assumed to be the proposed groundwater
containment measure because the slurry wall would remain permanently at the
Northeast Site. An infiltration gallery or shallow well injection would be removed
upon completion of the corrective action.
During installation of the slurry wall, five groundwater recovery wells would be
completed in the surficial aquifer for the removal of the contaminated groundwater.
The anticipated locations of these recovery wells are shown on Figure 3.1, but the
exact number and locations of these wells would be determined during the final
design of the corrective action. The drill cuttings produced from the completion of
the recovery wells would be managed according to the applicable federal and state
regulations.
Figure (Page 3-2)
Figure 3.1
Figure (Page 3-2)
Figure 3.1
Each groundwater recovery well would be approximately 37 ft deep to fully penetrate
the entire thickness of the surficial aquifer and to extend into the Hawthorn
Formation approximately 5 ft to provide a sump. Each well would also be completed
with stainless steel casing, a fully penetrating stainless steel well screen, and a
stainless steel, submersible, variable-speed pump. The fully penetrating well screen
and sump would allow the contaminated groundwater to be withdrawn from the entire
saturated thickness of the surficial aquifer. Each recovery well would be
individually controlled to optimize the well capture zone, and all of the recovery
wells would be equipped with flow meters to accurately measure the volume of
groundwater recovered. Each recovery well would also include a piezometer to monitor
the groundwater level in the well. After completion of the corrective action, all of
the recovery wells would be sealed and abandoned as required by the applicable
regulations.
A groundwater treatment system would be installed in an area just north of Building
1400 at the southern boundary of the Northeast Site (Figure 3.1). This treatment
system would have a capacity of 25 gallons per minute and would use an air stripper
to remove the VOCs and SVOCs from the contaminated groundwater. The groundwater
treatment system would be installed on a concrete pad that would be constructed with
appropriate slopes, sumps, and catchment basins to contain any potential leaks or
spills.
The groundwater recovery wells would be connected to the groundwater treatment system
by underground PVC pipe. Contaminated groundwater would be pumped from the recovery
wells to the treatment system where it would be placed in the influent storage tank
(Figure 3.2). Water from the influent storage tank would be pumped into the
pretreatment portion of the treatment system to remove naturally occurring iron and
suspended solids. The pretreatment unit would consist of a clarifier and sand filter,
and a flocculent would be added to the water in the clarifier to precipitate the
iron out of solution. Effluent from the clarifier would flow by gravity through the
sand filter and into a storage tank. Rejected water from the sand filter would flow
back to the clarifier. Sediment from the clarifier would be pumped to a sludge tank,
and the contents of the sludge tank would be manually pumped through a plate and
frame filter press. Effluent from the filter press would be routed to the storage
tank. The spent sand and filter cake from the sand filter and filter press would be
collected in 55-gallon drums, analyzed by the Toxicity Characteristic Leaching
Procedure, and then disposed of as solid or hazardous waste in accordance with the
applicable regulations. Water from the storage tank would be pumped to the air
stripper where the VOCs and SVOCs would be removed. Treated groundwater from the air
stripper would be pumped to the effluent storage tank and then to the Pinellas Plant
wastewater neutralization facility for final discharge into the Pinellas County
Sewer System.
Figure (Page 3-4)
Figure 3.2
The proposed corrective action would reduce the concentrations of the COCs in the
surficial aquifer groundwater to the media cleanup standards. The media cleanup
standards are the concentrations of the COCs that the EPA and FDEP approve as
acceptable for completion of the corrective action. For the Northeast Site, it has
been determined that the media cleanup standards will be the SDWA MCLs or the FDEP
drinking water standards for the COCs, whichever are more stringent (DOE 1993c,d;
1994b). For this EA, the media cleanup standards, SDWA MCLs, and the FDEP drinking
water standards for the COCs are collectively called the MCLs. Groundwater monitoring
would provide data to verify the achievement of the MCLs in the surficial aquifer,
to evaluate the efficiency and effectiveness of the corrective action, and to detect
contaminant migration resulting from the corrective action. Therefore, groundwater
monitoring would be conducted during the start-up and long-term operation of the
corrective action and for at least one year after completion of the corrective
action. During start-up and long-term operation, groundwater would be monitored in
15 monitoring wells located within and along the boundaries of the contaminant plume
and along the perimeter of the Northeast Site (Figure 3.1). Groundwater monitoring
after completion of the corrective action would be performed using 10 wells along
the perimeter of the Northeast Site (Figure 3.1). All of these monitoring wells were
installed for the Pinellas Plant RFI. The need for additional monitoring wells would
be identified during the final design or long-term operation of the corrective
action. If additional monitoring wells become necessary, they would be installed and
completed in a manner similar to the groundwater recovery wells except that they
would not be equipped with pumps. The need for and extent of long-term groundwater
monitoring after completion of the corrective action would be determined in the EPA-
and FDEP-approved Final Closure Report for the Northeast Site.
Most, if not all, of the areas to be disturbed during the corrective action
activities have been previously disturbed by Pinellas Plant operations and by the
various investigations of the Northeast Site, including the RFI. However, these
disturbed areas would be restored to their original conditions or as close to their
original conditions as possible. The disturbed areas would be graded to conform to
the surrounding land surface and to avoid the ponding of surface runoff. The areas
would then be revegetated with plant species that are common to the Pinellas Plant
(e.g., St. Augustine grass).
Once implementation of the proposed corrective action was approved and contracted
for, construction and installation of the slurry wall and the groundwater recovery
and treatment systems would take a maximum of 6 months. Most, if not all, of these
construction and installation activities would be performed concurrently. After the
construction and installation, the corrective action would be operated for a 1-year
start-up period, after which long-term operation would begin. Groundwater modeling of
the corrective action indicates that long-term operation would continue for 29 years
in order to meet the corrective action objectives and achieve the MCLs. During the 30
years of corrective action, approximately 70 million gallons of groundwater would be
recovered, treated, and discharged to the Pinellas County Sewer System. Total capital
costs (direct and indirect) for installation of the proposed corrective action would
be approximately $4.5 million, and the first-year operation and maintenance costs
would approximate $750,000. The total estimated cost for 30 years of operation and
maintenance of the proposed corrective action is $22.5 million (1992 dollars).
The corrective action would be performed in accordance with the HSWA and Hazardous
Waste Management Permits for the Pinellas Plant (EPA 1990a; FDEP 1994) and the EPA-
and FDEP-approved Corrective Measure Implementation Plan. Implementation of the
corrective action would require permits for the groundwater recovery and monitoring
wells and for the air stripper. The completion of each groundwater recovery and
monitoring well would require a "Permit to Construct, Repair, Modify or Abandon Well"
issued by the Southwest Florida Water Management District. Installation and
operation of the air stripper would require a "Permit to Operate/Construct Air
Pollution Sources" issued by the FDEP. Other Federal, state, and local permits
required for the proposed corrective action would be identified during the final
design and would be obtained prior to implementation of the proposed corrective
action.
The treated groundwater from the Northeast Site would be routed to the Pinellas Plant
wastewater neutralization facility for final discharge into the Pinellas County
Sewer System. The Pinellas Plant's discharge of wastewater to the sewer system is
subject to the Industrial Wastewater Discharge Permit, Permit Number 153-IE, issued
to the plant in 1994 by the Pinellas County Sewer System (PCSS 1994). The Pinellas
County Sewer Use Ordinance of April 1991 specifies standards for discharge to the
sewer system, but the ordinance does not specify any standards for organics. The
Pinellas Plant is required to meet the metals finishing industry standards for
organics, and the EPA standards (40 CFR 433) specify a pretreatment limit of 2.13
milligrams per liter (mg/L) for total toxic organics. Toxic organics, as defined by
the EPA, include dichloromethane, trichloroethene, toluene, and chloroethene.
Therefore, the limit for total toxic organics in the total Pinellas Plant discharge
is 2.13 mg/L (CH2M Hill 1989a; DOE 1992b).
In addition to the required permits, the following standard operating procedures were
incorporated into the proposed corrective action to reduce environmental impacts:
- Construction equipment used in the corrective action (e.g., backhoe and front-end
loader) would be equipped with appropriate emissions control devices to control
combustion emissions.
- Fugitive dust generated by corrective action activities (e.g., installation of the
soil/bentonite slurry wall) would be controlled with water sprays.
- All areas disturbed during the corrective action would be restored (graded and
revegetated) as soon as possible.
- The water level in the East Pond would be monitored during corrective action to
determine if and how much the water level is being lowered and to assess any adverse
effects on vegetation or wildlife in the East Pond. If the lowering of the water
level is appreciable or if any adverse effects on vegetation or wildlife are
observed, the DOE would develop and implement appropriate measures in consultation
with the appropriate regulatory agency or other authority. The DOE would also
evaluate the need for additional NEPA review and would conduct this review if
necessary.
Workers involved in the proposed corrective action would be subject to potential
exposure to contaminated groundwater and air emissions from the air stripper.
Workers would also be exposed to the physical hazards associated with installation,
operation, and maintenance of the corrective action (e.g., operating heavy
construction equipment). The corrective action would be performed in compliance with
all of the applicable health and safety requirements of the Occupational Health and
Safety Administration, as set forth in 29 CFR 1900-1910 and 1926, as well as all
applicable DOE and Pinellas Plant health and safety requirements. In addition, the
corrective action would be performed in compliance with a site health and safety
plan, as required by 29 CFR 1910.120; 29 CFR 1910.120 governs all work at
uncontrolled hazardous waste sites including worker training and medical monitoring.

3.2. OTHER ALTERNATIVES

3.2.1. No Action

The no action alternative would consist of continuing the interim corrective action
for the Northeast Site (subsection 1.4). The contaminated groundwater in the
surficial aquifer would continue to be recovered using existing recovery wells and
pumped to the existing groundwater treatment facility for the 4.5-Acre Site in the
northwest corner of the Pinellas Plant (Figure 1.4). This groundwater treatment
facility uses an air stripper to remove VOCs and SVOCs from contaminated
groundwater, and the effluent from this facility is pumped to the Pinellas Plant's
wastewater neutralization facility for eventual discharge into the Pinellas County
Sewer System. The interim corrective action includes a groundwater monitoring system
(CH2M Hill 1989a, 1991; DOE 1992b).
This alternative was evaluated during the CMS process. At the time the Northeast Site
was recommended for interim corrective measures, excess groundwater treatment
capacity was available at the 4.5-Acre Site facility because it was under interim
status and the facility had been designed with enough capacity for its anticipated
final corrective action. The 4.5-Acre Site will soon be proposed for final corrective
action; therefore, at the time when the Northeast Site is ready for its final
corrective measure, it is anticipated that the excess groundwater treatment capacity
at the 4.5-Acre Site facility will not be available (DOE 1993c). If the groundwater
treatment facility for the 4.5-Acre Site was used for the final corrective actions
for both the 4.5-Acre and Northeast Sites, one or both of the corrective actions
would have to operate at less than an optimum groundwater recovery rate. This could
extend the time necessary for completion of a corrective action and could present the
potential for offsite migration of contaminated groundwater.
During the CMS process for the Northeast Site, two other no action alternatives were
evaluated. The first no action alternative would consist of taking no corrective
action. The groundwater contaminant plume would remain in its present location and
condition, and the potential for offsite migration of the plume would continue to
exist for an indefinite period of time. The second no action alternative would
consist of taking no corrective action, but various institutional controls (e.g.,
deed restrictions) and groundwater monitoring would be implemented to prohibit or
restrict access to the contaminated groundwater and to detect any future migration of
the contaminant plume. These no action alternatives would not satisfy the
requirements of the HSWA Permit for the Pinellas Plant and would not meet the
established corrective action objectives for the Northeast Site (DOE 1993c).
Therefore, neither of these alternatives were considered in this EA.

3.2.2. Ultraviolet Oxidation

     The ultraviolet (UV) oxidation alternative for corrective action at the Northeast
     Site would be the same as the proposed action except that UV oxidation would be the
     primary groundwater treatment system instead of air stripping. The air stripper
     (Figure 3.2) would be replaced with a UV oxidation tank and a hydrogen peroxide
     tank. Hydrogen peroxide would be added to the contaminated groundwater to begin the
     destruction of the organic contaminants. The contaminated groundwater would then be
     exposed to UV light from a series of UV lamps in the UV oxidation tank which would
     complete the destruction of the majority of the organic contaminants. The
     contaminants would be oxidized to carbon dioxide, water, and inorganic salts.
     Partially oxidized or unoxidized contaminants, such as dichloromethane, could require
     additional treatment, and controls could be required for emissions created by the UV
     oxidation process depending on the type of system used. The UV oxidation alternative
     could be more expensive than pump-and-treat with air stripping, especially over 30
     years of corrective action (DOE 1993c).

3.3. ALTERNATIVES DISMISSED FROM FURTHER CONSIDERATION

     As stated in subsection 1.3, the CMS identified corrective action technologies that
     were screened to eliminate technologies that were not feasible to implement, were
     unlikely to perform satisfactorily or reliably, or may not achieve corrective action
     objectives with a reasonable period of time. Thirty-nine preliminary corrective
     action technologies were identified and screened for groundwater containment,
     collection, treatment, and disposal and for the disposal of solid wastes from
     groundwater treatment. These technologies included a slurry wall, sheet piling, and
     grout curtains for groundwater containment; recovery well and trench collection
     systems for groundwater collection; enhanced bioremediation, air stripping, UV
     oxidation, and filtration for groundwater treatment; an evaporation pond, shallow and
     deep well injection, and surface irrigation for groundwater disposal; and onsite and
     offsite landfill disposal of solid wastes from groundwater treatment. Eleven of the
     technologies were retained as feasible and, when combined, formed a number of
     technology options. From the technology options, pump-and-treat with air stripping
     and pump-and-treat with UV oxidation were identified as CMAs for the contaminated
     surficial aquifer groundwater at the Northeast Site. The CMAs were then evaluated
     against technical, environmental, human health, and institutional criteria according
     to the requirements of the HSWA Permit for the Pinellas Plant. Details on the
     screening of preliminary corrective action technologies and the CMA evaluations are
     provided in the CMS Report (DOE 1993c,d; 1994b).

4. AFFECTED ENVIRONMENT

4.1. WEATHER AND AIR QUALITY

4.1.1. Weather

The discussion below is based on data for Tampa, Florida, which is approximately 20
miles east of the Pinellas Plant. These data were provided primarily by the U.S.
Department of Commerce (NOAA 1991); the Pinellas County Department of Environmental
Management, Air Quality Division (PCAQD) (PCAQD 1989); and Trinity Consultants, Inc.
(Trinity 1990).
The weather of central Florida can be characterized as a subtropical savanna climate
with a primary wet season during the summer (June through September) and a secondary
wet season during the winter (December through February) (PCAQD 1989). Winters are
mild, and summers are long, rather warm, and humid. For the period 1961 through
1990, the average annual temperature was 72.3 F, and the average minimum and maximum
temperatures were 63.3 and 81.2 F, respectively (NOAA 1991). Median rainfall during
the primary wet season varies from 6 to 8 inches per month while median rainfall
during the winter ranges from 1.8 to 3 inches per month (PCAQD 1989). For the period
1961 through 1990, the average annual precipitation was 48.38 inches (NOAA 1991).
The 1990 wind rose for Tampa shows that the prevailing winds are from the east and
east-northeast. Winds from these directions occurred 29 percent of the year. The
next most prevalent winds are from the northeast, east-southeast, and west almost 24
percent of the year. The wind rose is omnidirectional, and wind from any direction
occurs no less than 2 percent of the year. The most common wind speeds are from 4.6
to 6.9 miles per hour (mph) and from 8.1 to 11.5 mph (Trinity 1990). The average wind
speed at the Tampa International Airport in 1988 was 7.9 mph, and average wind
speeds greater than 14 mph occur less than 1 percent of the year (PCAQD 1989). Winds
exceeding 25 mph are not common and usually occur only with thunderstorms or
tropical disturbances (NOAA 1991). Calm conditions with wind speeds less than 3 mph
occur only 5.8 percent of the time (Trinity 1990), while wind speeds less than 1 mph
occur less than 1 percent of the time (PCAQD 1989).
The potential for hurricanes and tropical storms exists in Pinellas County. The peak
hurricane frequency occurs in September with 3.4 storms per decade, and the
frequency of tropical storms is generally about the same as the frequency of
hurricanes (PCAQD 1989). Based on records from 1866 through 1982, the average
occurrence of a hurricane passing within a 50-nautical-mile radius of Tampa is 1 in
every 8.4 years. From 1950 to 1980, 50 tornado-like events occurred in Pinellas
County. Thirty-seven of these events were classified as tornadoes and 13 as
waterspouts coming ashore; most of these events (74 percent) occurred during April
through September. The probability of a tornado striking the Pinellas Plant is 1
chance in 2,326. Waterspouts moving ashore typically dissipate soon after reaching
land and would have very little potential for causing any damage at the plant (DOE
1983, 1990b).

4.1.2. Air Quality

The EPA has established the National Ambient Air Quality Standards (NAAQS) to protect
public health and welfare (40 CFR 50). The primary standards are designed to protect
the public health, and the secondary standards are designed to protect the public
welfare, including the effects of air pollution on visibility, materials, and
vegetation. The ambient air quality standards for the state of Florida and Pinellas
County are the same as the NAAQS (PC 1992a).
Stagnation does not occur in the Tampa Bay area because land-water temperature
differences always induce a wind circulation even if the large-scale wind gradient
is flat or zero. Consequently, the air quality in Pinellas County is among the best
in the nation for urban areas of similar size and density. Pinellas County continued
to meet the NAAQS for all pollutants during 1987 and 1988. For these two years, the
PCAQD reported 455 days with an Air Quality Index (AQI) of "Good" and 274 days with a
"Moderate" AQI; only 1 day was in the "Unhealthful" AQI level. The AQI is a
nation-wide standard method developed by the EPA for reporting daily air quality to
the public in a health-related manner. Data for 1989 and 1990 show horizontal trends
in the AQI and for all pollutants except for carbon monoxide, nitrogen dioxide, and
particulates. Carbon monoxide and particulates had nominally to moderately decreasing
trends. Nitrogen dioxide had a nominally increasing trend which is expected to
continue due to the growth in vehicle miles traveled in the county (PCAQD 1989,
1991).
The Pinellas Plant is a high-technology facility, and VOCs are exhausted from
approximately 200 chemical stacks and vents distributed over the roof of Building
100 (DOE 1991a). The Florida Air Toxics Permitting Strategy establishes a strategy
for controlling toxic air emissions from stationary sources to levels that will not
endanger public health. This policy includes the Florida Air Toxics Working List,
which establishes conservative 8-hour, 24-hour, and annual no-threat levels (NTLs)
for toxic chemicals and which is used by the FDEP and industry to determine air
toxics permitting needs. The strategy is based on comparing the predicted ambient
impact of individual toxic air contaminants with an estimate of the ambient exposure
level of each chemical that is not likely to cause appreciable health risks. The
policy has not been adopted as rule, but it is used as a guideline to identify
emission sources for air permit applications (FDEP 1991).
An air quality permit application for the Pinellas Plant (DOE 1992d) was prepared in
1992, and the FDEP issued an Air Emissions Permit, Permit Number A052-233355, in
1993 (FDEP 1993). Air contaminants that could be of concern are dichloromethane
(methylene chloride), trichloroethene, and 2,4,6-trichlorophenol. The ambient
concentrations of these contaminants at various plant boundary locations were
calculated using the Industrial Source Complex (ISC-2) dispersion model for
short-term applications (EPA 1992), a commercially available Gaussian plume model.
The highest calculated annual concentration of dichloromethane from Pinellas Plant
emissions was 0.0009 (9.0E-04) milligrams per cubic meter (mg/m3) at the south
property boundary. The north plant boundary is the boundary closest to the location
of the proposed groundwater treatment system; the calculated annual concentration of
dichloromethane at the north property boundary was less than 2.0E-04 mg/m3. The
annual NTL for dichloromethane is 2.1E-03 mg/m3. The calculated concentrations for
trichloroethene and 2,4,6- trichlorophenol were well below their respective NTLs at
all plant boundary locations (2,4,6-trichlorophenol does not have an established NTL,
so the NTL for phenol was used for comparison).

4.2. GEOLOGY

4.2.1. Soils

     The soil types at the Pinellas Plant are the Myakka Fine Sand, Wabasso Fine Sand, and
     Made-Land soils. These soils range in thickness from 5 to 50 ft across Pinellas
     County. The Myakka Fine Sands are gently sloping, moderately well drained soils that
     contain layers weakly cemented with organic matter at depths of 40 inches or less.
     The Myakka soils cover approximately 45 percent of the plant in the western half of
     the site. The Wabasso Fine Sands are nearly level, poorly drained soils, some of
     which have layers weakly cemented with organic matter. Light gray sands mixed with
     shell fragments are commonly found in the Wabasso soils between depths of about 50 to
     62 inches. The Wabasso soils are found in the far east portion of the plant,
     covering approximately 25 percent of the site. Made-Land soils consist of mixed sand,
     clay, hard rock, shells, and shell fragments that have been transported, reworked,
     and leveled during earth-moving activities. Made-Land soils are nearly level and
     excessively altered by man and are found beneath and north of Building 100 and west
     of the East Pond (SCS 1972).

4.2.2. Geology

Figure 4.1 shows a generalized geologic cross section in the vicinity of the Pinellas
Plant. Surficial deposits are terrace deposits consisting primarily of sands and
shelly sands that are classified as the Myakka and Wabasso soils. The Tampa Formation
has two parts: the lower part is known as the Tampa Limestone and is the uppermost
carbonate unit of the upper Floridan aquifer that totals several thousand feet in
thickness; the upper part of the Tampa Formation has a higher clay content and, with
the Hawthorn Formation, acts as a confining bed above the upper Floridan aquifer in
the immediate area of the Pinellas Plant. Well logs for the Pinellas Plant show that
the Hawthorn Formation and the clays of the upper Tampa Formation range from 55 to
78 ft in thickness. This variation in thickness is probably due to gradational
contact between the strata (i.e., the exact contact between the strata is not
clearly defined). Therefore, the confining bed consisting of the Hawthorn Formation
and the upper part of the Tampa Formation is collectively called the Hawthorn
Formation (DOE 1991b).
Figure (Page 4-4)
Figure 4.1
Sinkhole formation is common in Florida, and two types of sinkhole formation are
observed in Pinellas County. Cover-collapse sinkholes occur when a subsurface void
grows larger over time until the overlying sediment cannot support its own weight.
Cover-subsidence sinkholes develop gradually as limestone is removed through
dissolution and the overlying soil continuously fills the void. The depression
created at the surface is also slowly filled, and cover-subsidence sinkholes are
therefore more difficult to identify. The majority of sinkholes occur in northern
Pinellas County where the sediments mantling the limestone are 25 to 50 ft thick. Six
reported sinkholes are within a 5-mile radius of the Pinellas Plant; two of these
are classified as cover-subsidence sinkholes and could not be confirmed. The
probability of a sinkhole occurring at the Pinellas Plant is once every 1,340 years
(Beck and Sayed 1991).
Earthquakes have occurred in Florida. The earliest recorded and most severe
earthquake was on January 12, 1879, near St. Augustine; the only damage was minor
and in St. Augustine. Several other events of less intensity have been reported since
that time. There is no reasonable expectancy for damaging earthquakes at the
Pinellas Plant. The seismic risk map of the United States shows central and southern
Florida to be in Zone 0, which is defined as a "no damage" zone (Algermissen 1969).

4.3. HYDROLOGY

4.3.1. Surface Water

The terrain at the Pinellas Plant is generally flat. The total elevation difference
over the plant area is approximately 2 ft, and most of this variation is associated
with man-made structures. There is a slight downward slope in the southeast corner of
the plant area, but there are no topographic high points or lineaments that would
affect surface drainage. The plant is on the surface water divide of two drainage
subbasins. Flow in the northwestern half of the plant is to the west, and flow in the
southeastern half of the plant is to the southeast. Both of the subbasins drain into
Boca Ciega Bay and eventually into the Gulf of Mexico (Figure 1.1) (DOE 1991b).
No natural surface waters exist at the Pinellas Plant, but three man-made ponds, with
a combined surface area of approximately 5 acres, have been excavated initially as
borrow pits or for storm water retention. The East and West Ponds (Figure 1.2) were
excavated primarily as borrow pits and have capacities of 10 and 8 acre-ft,
respectively. The East and West Ponds have received various waste in the past and are
RCRA SWMUs (DOE 1991b). Both ponds were converted to storm water retention ponds and
now receive only storm water runoff (DOE 1987). Overflow from the East Pond
discharges through a county drainage pipe, south along Belcher Road, and then east
along Bryan Dairy Road until it empties into a county drainage ditch. Flow continues
southward, entering Cross Bayou Canal, Cross Bayou, and finally Boca Ciega Bay
(Figure 1.1). There is no discharge from the West Pond. The South Pond (Figure 1.2)
was constructed for storm water retention and has a capacity of 6 acre-ft. The
concrete-lined South Pond is connected to the East Pond by a closed underground
piping system that, if needed, would allow overflow from the East Pond to drain to
the South Pond. There is no evidence that any overflow drainage ever occurred, and
the South Pond is not a RCRA SWMU (DOE 1991b). Therefore, the South Pond is not
considered further in this EA.
The water in the East and West Ponds has been sampled at various times, including
during the RFI. Water quality investigations of the East and West Ponds in 1985 and
1987 indicated the presence of various contaminants including cadmium, chromium,
lead, manganese, mercury, pesticides, PCBs, and organic solvents (Fernandez 1985;
CH2M Hill 1987). RFI samples from the East Pond indicated mercury concentrations
slightly above the SDWA MCL and FDEP drinking water standard (DOE 1991b);
supplemental RFI sampling (Hammond 1992; Ingle 1992a,b) indicated that mercury was
not present above standards (DOE 1993b). RFI samples from the West Pond did not
contain concentrations of contaminants above SDWA MCLs and FDEP drinking water
standards. Based on surface water samples taken during the RFI, the East and West
Ponds have oxygen levels above the FDEP standard of 3.00 mg/L, which is sufficient to
support aerobic life. Most of the oxygen profiles of the ponds ranged from 7 to 10
mg/L, and this range is considered able to support healthy aquatic biological
conditions. Only oxygen levels 1 ft from the bottoms of the ponds showed any
depletion (DOE 1991b).
The Pinellas Plant is not in a floodplain, which is defined as an area having a 1 in
100 chance on average of being inundated due to rainfall in any year (DOE 1988; PCDP
1991a). The greatest amount of flood damage would be caused by hurricane tidal
flooding, and the U.S. Army Corps of Engineers has examined the Pinellas Plant in
relation to the design hurricane for the area. The design hurricane is the hurricane
that would occur in this area in 100 or more years. The maximum anticipated high
tide associated with the design hurricane would be approximately 14 ft above mean sea
level (MSL). The plant is several miles inland and has a minimum floor elevation of
18.5 ft above MSL; therefore, no damage from tidal flooding would be expected to
occur (DOE 1991a).
No municipal water supplies in Pinellas County are supplied by surface water due to
the limited dependable amount of surface water that is available and the high cost
of treatment to meet drinking water standards (SWFWMD 1988).

4.3.2. Groundwater

Pinellas County is in the west-central portion of the 7,300-square-mile Southern
West-Central Florida Groundwater Basin (SWCFGWB). The SWCFGWB contains a
multi-layered aquifer system that includes the surficial, intermediate, and Floridan
aquifers (SWFWMD 1988). In Pinellas County, the multi-layered, freshwater aquifer
system consists of the surficial and Floridan aquifers. The intermediate aquifer does
not exist in the county. Throughout the county, the surficial aquifer is unconfined
and close to the ground surface and, therefore, susceptible to contamination.
Infiltration to the surficial aquifer in Pinellas County is estimated to be 22 inches
per year. The surficial aquifer will not sustain adequate well yields, and the
surficial aquifer groundwater quality is generally poor due to high naturally
occurring concentrations of chloride, iron, and organic constituents. Consequently,
no municipal water supplies are taken from the surficial aquifer (SWFWMD 1988;
Fernandez and Barr 1983; DOE 1993c).
The Floridan aquifer can be divided into the lower and upper Floridan aquifers. The
lower Floridan aquifer does not contain potable water and is not considered further
in this EA. The upper Floridan aquifer is the principal and most productive source of
potable groundwater in Pinellas County, but withdrawal from the aquifer is
restricted due to the available amount of good quality water and the aquifer's
sensitivity to saltwater encroachment. Recharge rates to this aquifer in Pinellas
County have been estimated to be from zero to less than 2 inches per year (Geraghty
and Miller 1976; Stewart 1980; SWFWMD 1988).
The strata of concern underlying the Pinellas Plant are, in ascending order, the
Tampa Limestone (upper Floridan aquifer), Hawthorn Formation, and surficial aquifer.
The Tampa Limestone is the main source of water for Pinellas County and surrounding
counties; however, the fresh water zone in the upper Floridan aquifer is thin. The
Hawthorn Formation is an effective aquitard in most areas of Pinellas County but, if
breached, could allow flow from the surficial aquifer to the Tampa Limestone. The
surficial aquifer is not currently used to supply municipal water; it is unconfined,
shallow, and susceptible to contamination (DOE 1991b; SWFWMD 1988).
At the Pinellas Plant, the top of the surficial aquifer is from 0 to 4 ft below the
ground surface, and the aquifer has an average thickness of 32 ft. Horizontal and
vertical hydraulic conductivities determined during the RFI suggest that
stratigraphic control of groundwater flow in the aquifer is not a dominant process,
and the ability of water to flow horizontally and vertically in the surficial aquifer
is approximately the same. Storage coefficients for the surficial aquifer are also
small compared to expected values for an unconfined aquifer, indicating that the
effective porosity of the aquifer is low (DOE 1991b). A recharge area for the
surficial aquifer is east of the West Pond, corresponding to a drainage basin divide.
This divide is historically documented and is considered to be a natural groundwater
divide (Fernandez 1985). Data collected for the RFI suggest that the direction of
groundwater flow does not vary appreciably during the year, and the groundwater flow
pattern across the plant site is expected to remain relatively constant throughout
the year. Groundwater in the surficial aquifer flows east, southeast, and northwest
from the groundwater divide. The gradient to the northwest seems to have increased,
possibly due to the withdrawal of groundwater for the pump-and-treat project at the
4.5-Acre Site that is adjacent to the plant to the northwest. Other man-made
influences, including nearby drainage channels, may periodically act as zones of
recharge or discharge. The depth to the water table during the RFI ranged from less
than 0.5 to approximately 6 ft (DOE 1991b).
The Hawthorn Formation is approximately 70 ft thick in the wells drilled through it
at the Pinellas Plant. The Hawthorn Formation has a hydraulic conductivity that is
several orders of magnitude less than that of the surficial aquifer or upper Floridan
aquifer; therefore, the Hawthorn Formation is considered to act as an aquitard in
the area of the Pinellas Plant (DOE 1991b). Slow vertical movement of water through
the Hawthorn Formation has also been predicted by the U.S.Geological Survey (USGS).
The USGS estimated that the vertical movement of water through 37 ft of the Hawthorn
Formation would take 7,000 years (Hickey 1982).
The hydraulic properties of the upper Floridan aquifer have not been measured at the
Pinellas Plant. Regional potentiometric surface data indicate that there is little
variation in the potentiometric surface on a seasonal or annual basis and that
groundwater flow in the aquifer in the vicinity of the plant is primarily
east-northeast toward Tampa Bay (Barr and Schiner 1984; Barr 1984, 1985; Barr and
Lewelling 1986; Lewelling 1987). Recharge to the upper Floridan aquifer is very low
where the aquifer is overlain by thick, impermeable strata. Estimates of the recharge
rate to the aquifer at the Pinellas Plant are in the range of zero to less than 2
inches per year (SWFWMD 1988; Stewart 1980).
Since the upper Floridan aquifer is the primary source of drinking water in Pinellas
County, the vertical flow of water from the surficial aquifer through the Hawthorn
Formation is a concern. Potentiometric data collected during the RFI show that there
is a potential for the downward movement of water from the surficial aquifer to the
upper Floridan aquifer. The estimated recharge from the Hawthorn Formation to the
upper Floridan aquifer ranges from 0.36 to 0.52 inch per year (DOE 1991b), which is
consistent with other estimates for Pinellas County that range from zero to less than
2 inches per year (SWFWMD 1988; Stewart 1980). With the flow-restricting properties
of the Hawthorn Formation, appreciable migration through competent sections of the
Formation is unlikely. However, features such as sinkholes and abandoned water wells
that may breach the Formation could become hydraulic pathways from the surficial
aquifer through the Hawthorn Formation. No recent sinkholes have been found at the
Pinellas Plant, and the probability that a sinkhole will occur at the plant is
considered to be very low (see subsection 4.2.2). Two wells are known to have been
completed in the upper Floridan aquifer beneath Building 100. The well under the
north-central portion of the building is documented as grouted and sealed (DOE
1991b). There is no documentation on the abandonment of the other well, but
interviews of Pinellas Plant employees indicate that the well was sealed with
concrete.
Due to the potential head difference between the surficial aquifer and the upper
Floridan aquifer, the existence of a conduit or breach through the Hawthorn
Formation would be evident in the surficial aquifer as a cone of depression in the
water table surface. An examination of water levels measured at the Pinellas Plant
during four RFI sampling events indicate no areas of localized water table depression
at the plant. Furthermore, the Hawthorn Formation has a fairly high cation exchange
capacity (CEC) and a very low permeability, and positively charged metal ions are not
expected to migrate through the Hawthorn Formation due to this high CEC. Any
brecciated zone associated with a sinkhole would be expected to have geochemical
properties similar to the Hawthorn Formation, such as a high CEC. Therefore, downward
contaminant migration through the Hawthorn Formation to the upper Floridan aquifer
is considered to be unlikely. Three upper Floridan aquifer wells were sampled in 1988
and during the RFI and were consistently free of any contamination. These wells are
downgradient from the contaminated groundwater plume at the Northeast Site (DOE
1991b).
Pinellas County is one of 16 counties in the Southwest Florida Water Management
District, and groundwater from the Floridan aquifer provides over 95 percent of the
water used in the district (DOE 1991a). Some small private and commercial users
operate wells in permeable portions of the Hawthorn Formation, and available
information indicates that there are no permitted production wells completed in the
surficial aquifer (DOE 1991b). There are several municipal well fields in northern
Pinellas County. The closest well field is approximately 5 miles northwest of the
Pinellas Plant and has an average yield of 1.1 million gallons per day (SWFWMD 1988).
There are no municipal well fields in southern Pinellas County due to saltwater
intrusion in the upper Floridan aquifer. Pinellas County does not have adequate
freshwater resources within its boundaries to support current and future demands.
Consequently, about 90 percent of the municipal water supply is imported from
adjacent counties (Geraghty and Miller 1976; SWFWMD 1988).
An inventory of all wells within a 1-mile radius of the Pinellas Plant was compiled
from Southwest Florida Water Management District records. About 240 wells, ranging
from 1 inch to 10 inches in diameter, were identified for the nine land sections in
the vicinity of the plant, not including observation, test, or abandoned wells (CH2M
Hill 1987; DOE 1990a). Based on the reported screen depths for the wells, all of the
wells have been completed in the upper Floridan aquifer or in a permeable section of
the Hawthorn Formation. The wells are used primarily for agricultural (irrigation)
purposes, but domestic and recreational uses (e.g., lawn irrigation and swimming
pools) are common (DOE 1991b).
In 1990, the water usage in Pinellas County was approximately 102 million gallons per
day. Of this usage, 85.4 million gallons per day were for potable uses, 16.5 million
gallons per day were for agriculture, and 0.02 million gallons per day were for
industrial pumpage. The projected water demands for Pinellas County are 110 million
gallons per day in 1995 and 118 million gallons per day in the year 2000, which
represent increases of approximately 8 percent and 16 percent over the 1990 usage,
respectively (PCDP 1991b). The water used at the Pinellas Plant is provided by the
Pinellas County Water System, and the plant used a total of 74 million gallons of
potable water during 1990 (DOE 1991a). In the future, the greater demands for water
resources in the Pinellas County region will be met primarily by expanding well
fields tapping the upper Floridan aquifer. The surficial aquifer is not capable of
sustaining adequate well yields, and this aquifer is therefore not expected to
experience any increased usage (DOE 1991b).

4.4. FLORA AND FAUNA

4.4.1. Flora and Fauna

The Pinellas Plant is in an area that is classified as pine flatwoods, which is the
most extensive forest community in Pinellas County (PCDP 1991b). Pine flatwoods and
remnant or disturbed pine flatwoods occur outside and along the western,
northwestern, and southwestern boundaries of the Pinellas Plant (BDA 1992).
The pine flatwoods outside the western, northwestern, and southwestern boundaries of
the Pinellas Plant are dominated by slash pine with wax myrtle, saw palmetto, shrub
verbena, broomsedge, groundsel tree, blackberry, live oak, hat pins, Virginia
creeper, laurel oak, muscadine, gallberry, bracken fern, pawpaw, false goldenrod,
winged sumac, blueberry, blackroot, St. Johns wort, fetterbush, popcorn tree,
catbrier, and Chapman's oak. Wildlife observed using the pine flatwoods include the
osprey, mourning dove, fish crow, mockingbird, pine warbler, rufous-sided towhee, box
turtle, eastern black racer, armadillo, red-bellied woodpecker, and marsh rabbit (BDA
1992).
The majority of the Pinellas Plant has been developed. Undeveloped areas of the plant
are a large, maintained grass area and the East and West Ponds in the northern
portion of the plant and a maintained grass area and the South Pond along the
southern boundary of the plant. The grasses in the maintained areas are primarily
St. Augustine and crabgrass. Wildlife observed in the northern grass area include
mourning dove, boat-tailed grackle, mockingbird, starling, meadowlark, fish crow,
mottled duck, and killdeer. Monk parakeets were also observed flying over the
maintained grass areas, and there is a nesting colony in the Florida Power electrical
substation in the western portion of the plant (BDA 1992).
The periphery of the East Pond is dominated by cattails. Other vegetation at the edge
and on the bank of the East Pond includes pennywort, groundsel tree, Brazilian
pepper, dog fennel, hempweed, crabgrass, carpet-weed, Carolina willow, beggar ticks,
marsh fleabane, and ragweed. Wildlife using the East Pond include the common
moorhen, boat-tailed grackle, red-winged blackbird, common tern, snipe, green-backed
heron, Florida water snake, and laughing gull. Common plants such as pennywort,
hempweed, Carolina willow, and cattails were observed at the West Pond. Wildlife
associated with the West Pond include the great egret, common tern, double-crested
cormorant, little blue heron, red-winged blackbird, boat-tailed grackle, mourning
dove, Savannah sparrow, and marsh rabbit. There is an osprey nest at the top of a
light pole west of the West Pond (BDA 1992).
Environmental surveys of the East and West Ponds were conducted in 1989. Aquatic
species identified during the surveys included 19 species of phytoplankton and
zooplankton. Only two species of fish were identified. Neither of these species was a
game fish, and all of the fish captured were less than 5 centimeters in size. A
smooth softshell turtle was also captured (MEE 1989). During the RFI, turtles were
commonly observed in the East and West Ponds (DOE 1991b).

4.4.2. Threatened and Endangered Species

On July 17, 1991, the Fish and Wildlife Service (FWS) was consulted regarding
federally listed, threatened or endangered species that may be present at the
Pinellas Plant (Appendix A). According to the FWS, the Pinellas Plant is within the
historic range of the endangered Florida golden aster. If no pine scrub vegetation
exists at the plant, it is unlikely that this species is present. The threatened
Eastern indigo snake may inhabit the Pinellas Plant, and the endangered southern
bald eagle and wood stork may potentially feed in the storm water retention ponds at
the plant. The nearest bald eagle nest is about 2 miles southwest of the plant near
Cross Bayou. The eagles could feed as far north as the storm water retention ponds,
but their feeding is most likely concentrated in Cross Bayou. Contaminants from the
plant entering the Cross Bayou watershed could have some adverse effect on the
eagles, but other activities within the plant site are not likely to have a direct
effect on the nesting eagles (Carroll 1991). In 1992, the FWS stated that there had
been no change in the federally listed, threatened or endangered species potentially
present at the Pinellas Plant (PC 1992b).
The state of Florida provides endangered or threatened species protection and also
provides protection for species of special concern (SSC). SSC are those species
that, although relatively abundant and/or widespread in the state, may be especially
vulnerable to certain types of environmental change and/or have experienced
long-term population declines and could become threatened or endangered if not
protected. State-listed species (endangered, threatened, or SSC) with a potential for
occurring at the Pinellas Plant include the gopher tortoise, tricolored heron,
little blue heron, snowy egret, Florida burrowing owl, Sanibel lovegrass, Tampa
vervain, and scrub palmetto (BDA 1992).
No federally listed, threatened or endangered species were observed at the Pinellas
Plant. One little blue heron was observed foraging in the West Pond. This
medium-sized wading bird is state-listed as SSC due to the decrease in its numbers
over the past few decades and the recent loss of wetlands habitat throughout
Florida. Although the little blue heron was observed at the Pinellas Plant, no
habitat for rookeries (i.e., nesting and breeding areas) for these or other wading
birds occur at the plant. Several wading birds and waterfowl, including the little
blue heron, snowy egret, and tricolored heron, could occasionally use the storm water
retention ponds at any time of the year for foraging; however, there is a higher
potential for smaller wading birds to use these ponds. No bald eagles or wood storks
were observed at the plant, but these species may also forage in the storm water
retention ponds. Listed plant species are not expected to occur at the Pinellas
Plant, because the majority of the site has been disturbed, and because appropriate
habitat for the Florida golden aster does not exist at the plant (BDA 1992).

4.4.3. Wetlands

     The FWS has designated the East and West Ponds as wetlands (DOI n.d.). Public access
     to all of the ponds is restricted. Employees of the Pinellas Plant have access to
     the ponds, but the ponds are not used in any recreational capacity. There are no
     plans to use the ponds in the foreseeable future for any purpose other than storm
     water retention (DOE 1991b).

4.5. CULTURAL RESOURCES

     There are a number of sites of historical and archaeological significance in Pinellas
     County, but none of these sites is close to the Pinellas Plant. The closest cultural
     resource sites are the Long Bayou temple and burial mound and the Oakhurst Mound
     burial mound (archaeological sites), approximately 3 miles southwest of the plant
     (DOE 1983; PCDP 1991a). Consultation with the Florida State Historic Preservation
     Officer confirmed that no historical or archaeological sites listed or eligible for
     listing in the National Register of Historic Places are recorded or considered
     likely to be present within the Pinellas Plant boundaries (Percy 1991).

5. ENVIRONMENTAL IMPACTS

The environmental impacts of the proposed corrective action and the reasonable
alternatives to it are discussed in this section. The environmental components
(e.g., human health and groundwater) addressed in this section are limited to those
that may be affected by the corrective action alternatives. The environmental
impacts are based on conservative assumptions and impact assessment procedures and
thereby represent a realistic upper limit on the severity of the impacts that may
occur. The actual impacts that would occur would probably be less severe than those
identified here.
The cumulative environmental impacts of the proposed corrective action and other
actions at the Pinellas Plant are also discussed in this section. Other corrective
actions for contaminated surficial aquifer groundwater (i.e., for the 4.5-Acre Site
and Building 100 and West Fenceline Areas) would result in the same or similar
environmental impacts as would the proposed action, such as the temporary disturbance
of soils and the withdrawal of surficial aquifer groundwater. These impacts are
discussed in this section. Leasing all or portions of the Pinellas Plant to
commercial enterprises may also have environmental impacts. The impacts of commercial
leasing on human health, soils, surface water, flora and fauna, and cultural
resources were determined to be negligible and are not addressed in this section. The
impacts of commercial leasing on air quality, the withdrawal of surficial aquifer
groundwater, and the discharge of treated groundwater to the Pinellas County Sewer
System are of concern and are discussed in this section.

5.1. HUMAN HEALTH EFFECTS

     The average and maximum carcinogenic and noncarcinogenic risks for a future resident
     of the Northeast Site, in the absence of any corrective action (including the
     interim corrective action), were estimated to evaluate the human health risks from
     the contaminated groundwater at the Northeast Site. The estimates were performed in
     accordance with CERCLA guidance for the evaluation of human health (EPA 1989) and
     focused on the exposure to contaminants in surficial aquifer groundwater, which is
     not a primary drinking water source. The average and maximum observed concentrations
     of the COCs in surficial aquifer groundwater were used, and it was assumed that the
     future resident uses water from a contaminated onsite well for domestic purposes
     such as irrigation, swimming, and general cleaning. Due to the naturally poor quality
     of the surficial aquifer groundwater, it was further assumed that the future resident
     receives uncontaminated drinking water from a municipal supply. In this scenario,
     the future resident would be exposed to the COCs by the inhalation of COCs from
     contaminated groundwater and direct contact (dermal absorption) with contaminated
     groundwater.
     The estimated average carcinogenic risk from exposure during the childhood and adult
     years is 6 excess cancers in an exposed population of 100,000 persons (6E-05). The
     estimated maximum carcinogenic risk from exposure during the childhood and adult
     years is 2 excess cancers in an exposed population of 10 persons (2E-01). The actual
     risk would be below the maximum risk, but the maximum risk is of potential concern
     because it exceeds the EPA upperbound target carcinogenic risk of no more than 1
     excess cancer observed in a population of 10,000 people exposed (1E-04) (EPA 1988b)
     and the FDEP acceptable target carcinogenic risk of no more than 1 excess cancer
     observed in a population of 1,000,000 people exposed (1E-06). Exposure to the
     average observed concentrations of COCs would not result in the potential for
     noncarcinogenic public health risks (e.g., liver degeneration), but exposure to the
     maximum observed concentrations would have the potential for noncarcinogenic risks.
     As with the carcinogenic risk, the actual noncarcinogenic risk would be below the
     maximum risk.

5.1.1. Proposed Corrective Action

     The proposed corrective action would be complete in 30 years and would lower the
     concentrations of the COCs in the surficial aquifer groundwater to the MCLs for the
     Northeast Site. The MCLs for the Northeast Site are the SDWA MCLs or the FDEP
     drinking water standards for the COCs, whichever are more stringent (subsection
     3.1). The SDWA MCLs or the FDEP drinking water standards for the COCs are equal to or
     less than the contaminant concentrations that would achieve the EPA upperbound target
     carcinogenic risk of no more than 1E-04 excess cancer (EPA 1988b) or the FDEP
     acceptable target carcinogenic risk of no more than 1E-06 excess cancer. Therefore,
     1E-04 represents a realistic upper limit for the carcinogenic public health risks
     from drinking groundwater from the surficial aquifer after the proposed corrective
     action at the Northeast Site. The proposed corrective action would similarly reduce
     the potential for noncarcinogenic public health risks, and other corrective actions
     for contaminated surficial aquifer groundwater would further reduce public health
     risks. Again, use of the surficial aquifer as a drinking water supply is very
     unlikely due to the limited availability and naturally poor quality of the
     groundwater in the aquifer.

5.1.2. No Action

     The no action alternative would also lower the concentrations of the COCs in the
     surficial aquifer groundwater to the MCLs for the Northeast Site because the interim
     corrective measure would be continued. This would lower the public health risks from
     the contaminated groundwater to or below the EPA upperbound and FDEP acceptable
     target carcinogenic risks. However, the interim corrective measure probably could not
     withdraw groundwater at as large a rate as the proposed corrective action because it
     would share the groundwater treatment facility with the corrective measure for the
     4.5-Acre Site. This would result in a longer corrective action which would prolong
     the potential for public health risks. In addition, a less than optimum groundwater
     withdrawal rate for the interim corrective measure could present the potential for an
     increasing contaminant plume and possibly for offsite migration of the contaminant
     plume. This could increase the potential for public health risks from the
     contaminated surficial aquifer groundwater.

5.1.3. UV Oxidation

     The alternative action of pump-and-treat with UV oxidation would also lower the
     concentrations of the COCs in the surficial aquifer groundwater to the MCLs for the
     Northeast Site. This would lower the public health risks from the contaminated
     groundwater to or below the EPA upperbound and FDEP acceptable target carcinogenic
     risks within approximately the same time period as the proposed corrective action.
     Groundwater treatment with UV oxidation would involve the use of hydrogen peroxide
     and UV light. Due to this, there would be an extremely small potential for public
     exposure to hydrogen peroxide and UV light which could result in a very small
     increase in the public health risks from this alternative corrective action.

5.1.4. Corrective Action Worker Health

     The average and maximum carcinogenic and noncarcinogenic risks to a corrective action
     worker were also estimated for the proposed action. Again, the average and maximum
     observed concentrations of COCs were used. Corrective action workers could be exposed
     to the inhalation of the volatile and semivolatile COCs and to direct contact with
     the contaminated groundwater while working on the proposed corrective action (e.g.,
     performing maintenance on the groundwater treatment system). The estimated maximum
     carcinogenic risk is 5 excess cancers in an exposed population of 100 workers
     (5E-02); the estimated average carcinogenic risk is 5 excess cancers in an exposed
     population of 100,000 workers (5E-05). Only the estimated maximum carcinogenic risk
     exceeds the EPA upperbound carcinogenic risk of 1E-04 (EPA 1988b), but both the
     estimated maximum and average carcinogenic risks exceed the FDEP acceptable target
     carcinogenic risk of 1E-06. Exposure to the maximum observed concentrations of COCs
     would also have the potential for noncarcinogenic risks to corrective action workers.
     The actual carcinogenic and noncarcinogenic risks to corrective action workers would
     be below the maximum risks due to measures implemented as part of the site health
     and safety plan (e.g., the use of personal protective equipment).
     The no action and pump-and-treat with UV oxidation alternatives could also expose
     corrective action workers to inhalation of and direct contact with the same COCs at
     the same concentrations. Therefore, health risks to corrective action workers for
     these alternatives would be very similar to those for the proposed corrective
     action. The potential for health risks to corrective action workers would be
     prolonged for the no action alternative because the interim corrective measure might
     have to be performed longer due to a reduced groundwater recovery rate. The health
     risks to corrective action workers could be slightly increased for the UV oxidation
     alternative action because there would also be a potential for exposure of the
     workers to hydrogen peroxide and UV light.
     The potential exposure of corrective action workers to contaminants are and would be
     controlled by performing all corrective actions (e.g., 4.5-Acre Site and Building
     100 Area) in accordance with all applicable health and safety requirements and by
     implementing a site health and safety plan. Additional details on the applicable
     health and safety requirements and a site health and safety plan are provided in
     subsection 3.1.

5.2. AIR QUALITY

5.2.1. Proposed Corrective Action

     The proposed corrective action would result in combustion emissions from construction
     equipment and possibly fugitive dust from surface disturbing activities such as the
     installation of the groundwater treatment system. The combustion emissions from the
     construction equipment (e.g., hydrocarbons and carbon monoxide) would be temporary
     in duration (three weeks maximum) and small in amount due to the small quantity of
     equipment involved. The construction equipment would be equipped with the appropriate
     emissions controls. The amount of fugitive dust generated by the corrective action
     would also be small due to the nature of the soils and the small areas that would be
     disturbed. If necessary, fugitive dust would be controlled with water sprays. The
     future installation of new groundwater recovery and monitoring wells and associated
     piping for the proposed corrective action and other corrective actions (e.g.,
     Building 100 Area) would also result in combustion emissions and possible fugitive
     dust. These activities would be isolated incidents of very short duration, and the
     emissions and dust would be controlled with appropriate emissions controls and water
     sprays. Based on the existing air quality and wind circulation in Pinellas County
     (subsection 4.1), combustion emissions and fugitive dust from the proposed corrective
     action and other corrective actions would not be expected to result in any
     violations of air quality standards or any adverse effect on the AQI.
     The major air quality concern for the proposed corrective action would be the
     emission of VOCs and SVOCs from the air stripper in the Northeast Site groundwater
     treatment system. These emissions would occur in conjunction with the same type of
     emissions from the 4.5-Acre Site groundwater treatment system. This concern was
     evaluated by first examining the two operational scenarios for the groundwater
     treatment systems for the Northeast and 4.5-Acre Sites.
     The first operational scenario would be the operation of one groundwater treatment
     system at the 4.5-Acre Site for all of the corrective actions. This treatment system
     would operate at a capacity of 50 gallons per minute. The Northeast Site would
     contribute approximately 25 gallons per minute (the amount proposed for the separate
     Northeast Site groundwater treatment system), and the 4.5-Acre Site would contribute
     approximately 20 gallons per minute (the design capacity for the 4.5-Acre Site
     treatment system before the interim corrective action at the Northeast Site). The
     Building 100 and West Fenceline Areas could contribute 1 to 5 gallons per minute. The
     concentrations of the COCs in the groundwater at the Northeast Site are
     substantially higher than the concentrations of the COCs in the groundwater at the
     4.5-Acre Site and the Building 100 and West Fenceline Areas. Therefore, the
     contaminant concentrations entering the treatment system in this scenario would be
     less than those in the Northeast Site groundwater due to the dilution of the COCs by
     groundwater from the 4.5- Acre Site. The treatment of contaminated groundwater from
     the Building 100 and West Fenceline Areas would result in further dilution of the
     contaminants. Table V.1 shows the estimated concentrations of the COCs in the
     influent to the groundwater treatment system that is proposed for the final
     corrective action at the Northeast Site (DOE 1993c,d; 1994b). These estimated
     concentrations reflect dilution of the COCs in the Northeast Site groundwater by the
     simultaneous recovery of uncontaminated groundwater during the corrective action, but
     they do not reflect the additional dilution that would be caused by the groundwater
     from the 4.5-Acre Site and the Building 100 and West Fenceline Areas. For this
     operational scenario, the concentrations of the COCs in the influent to the 4.5-Acre
     Site treatment system would be expected to be less than those shown in Table V.1.

            Table V.1. Influent Contaminant Concentrations and Maximum Emissions Rates for
                                   the 4.5-Acre Site Air Strippers(a)
                                               Influent Concentration            Maximum Emission Rates
           Contaminant of Concern                  (ug/L)2                          (pounds per hour)(b)
       Benzene                                        50                            0.00125
       Dichloromethane                             3,000                            0.075
       Chloroethene                                1,000                            0.025
       1 ,2.trans.dichloroethene                     100                            0.0025
       Trichloroethene                             1,300                            0.0325
       4-methylphenol                              1,700                            0.0425
        a The influent contaminant concentrations are the estimated concentrations of the COCs in the 
          influent to the groundwater treatment system that is proposed for the final corrective 
          action at the Northeast Site.  The influent contaminant concentrations in micrograms per 
          liter (ug/L) were estimated by computer modeling used to simulate groundwater conditions 
          for the proposed Northeast Site corrective actions(subsection 5.4.2) (DOE 1993c, d; 1994b). 
          The influent contaminant concentrations reflect dilution of the contaminants by 
          uncontaminated groundwater but do not reflect additional dilution by groundwater from the 
          4.5-Acre Site and Building 100 and West Fenceline Areas.
        b it was assumed that the 50 gallons par minute capacity of the 4.5-Acre Site groundwater 
          treatment system would be provided by two air strippers operating in series. The maximum 
          emission rates were ceIculated asauming complete volatilization of all COCs.
     The second operational scenario would be the operation of two groundwater treatment
     systems for the corrective actions. One treatment system would be at the 4.5-Acre
     Site, and the other treatment system would be at the Northeast Site. The treatment
     system at the Northeast Site would also use an air stripper which would have a
     capacity of 25 gallons per minute. The concentrations of the COCs in the influent to
     the Northeast Site treatment system would be expected to be the same as or very
     similar to those shown in Table V.1. The 4.5-Acre Site treatment system would
     continue to treat contaminated groundwater from the 4.5-Acre Site and possibly from
     the Building 100 and West Fenceline Areas. The treatment system would operate at
     less than 50 gallons per minute (estimated maximum of 25 gallons per minute), and the
     concentrations of the COCs in the influent to the system would be substantially lower
     than those shown in Table V.1.
     Both of the operational scenarios described above would result in the emission of
     VOCs and SVOCs from air strippers in the groundwater treatment systems. The first
     scenario would create emissions from a single groundwater treatment system based on a
     system capacity of 50 gallons per minute and influent contaminant concentrations
     somewhat less than those shown in Table V.1. The second scenario would include two
     separate groundwater treatment systems which would have a combined capacity of
     approximately 50 gallons per minute. The concentrations of the COCs in the influent
     to one treatment system would be the same as or very similar to those shown in Table
     V.1, and the influent contaminant concentrations for the other treatment system
     would be less than those shown in Table V.1. Based on the treatment system capacities
     and the influent contaminant concentrations for the two scenarios, the emission of
     VOCs and SVOCs by the first operational scenario would be expected to be greater
     than that by the second scenario. Furthermore, the first scenario would have a single
     point source of emissions while the second scenario would have two separate point
     sources of emissions. Two separate point sources of emissions would result in lower
     concentrations of contaminants in the ambient air due to increased dispersion of the
     contaminants, the orientation of the point sources relative to the Pinellas Plant
     boundary, and the prevailing wind pattern at the Pinellas Plant. To be conservative
     in the assessment of air quality impacts, the first operational scenario was analyzed
     using a groundwater treatment system capacity of 50 gallons per minute and the
     influent contaminant concentrations shown in Table V.1.
     The air quality impacts of the first operational scenario were analyzed using the
     ISC-2 dispersion model (EPA 1992) to calculate the concentrations of the COCs that
     would occur at various Pinellas Plant boundary locations due to the air stripper
     emissions. Table V.1 shows the concentrations of the COCs in the treatment system
     influent and the maximum air stripper emission rates that were used in the emissions
     calculations. It was assumed that the 50 gallons per minute capacity of the 4.5-Acre
     Site groundwater treatment system would be provided by two air strippers operating
     in series. It was also assumed that the COCs volatilized completely in the air
     strippers and that each air stripper was equipped with an emissions tower 42.5 ft in
     height, which is the height of the existing 4.5-Acre Site air stripper tower. Other
     assumptions and model inputs were as follows:
     - Meteorological data from the Tampa International Airport for 1982 through 1986 were
       used to establish a meteorological data file for input to the model.
     - Emissions from the air strippers are continuous (8,760 hours per year). A generic
       emission rate of one gram per second was used.
     - The diameter of the air stripper towers (2 ft) and flow rate (400 standard cubic ft
       per minute) were used to calculate the exit velocities of the emissions in meters
       per second. Due to the 4.5-Acre Site's characteristics, the effects of buildings
       (i.e., downwash) was not considered, and the modeling was performed in the urban
       mode.
     - The height of the concentration calculations was ground level.
     - The modeling output was placed on a 330-ft, two-dimensional grid for the
       determination of critical receptor locations and the concentration at the south
       Pinellas Plant boundary location.
     The ISC-2 modeling was used to establish the location of the critical receptor, which
     would be the receptor that would receive the maximum impact from the 4.5-Acre Site
     air stripper emissions. For the annual and 24-hour contaminant concentrations, the
     critical receptor was approximately 330 ft due west of the 4.5-Acre Site air
     strippers; the critical receptor for the 8-hour contaminant concentrations was
     approximately 330 ft northwest of the air strippers. These critical receptor
     locations are within the 4.5-Acre Site, which is leased and is therefore not
     considered to be DOE property. Due to the heights of the air stripper towers and the
     exit velocities of the emissions, the maximum contaminant concentrations would not
     occur closer to the 4.5-Acre Site air strippers than approximately 330 ft and would
     therefore not occur at actual Pinellas Plant boundary locations. The ISC-2 modeling
     was also used to establish the approximate area of the emissions impacts.
     Contaminant concentrations would be less than the respective NTLs up to approximately
     2970 ft to the west, approximately 1980 ft to the north, approximately 1650 ft to
     the east, and approximately 3300 ft to the south of the 4.5-Acre Site air strippers.
     Contaminant concentrations beyond this impact area would be essentially zero. The
     geometry of the air emissions impact area would be due primarily to the relative
     frequencies of the omnidirectional winds at the Pinellas Plant (subsection 4.1.1).

Table V.2.  Calculated Contaminant Concentrations at the Critical Receptor Locations Versus No Threat Levelsa
     Contaminant of Concern       8-Hour            8-Hour NTL     24-Hour           24-Hour NTL     Annual            Annual NTL
                                  Concentration                    Concentration                     Concentration     
     Benzene                      4.7E-05           0.03           2.3E-05           0.0072          3.8E-06           0.00012
     Dichloromethaneb             3.0E-03           1.74           1.4E-03           0.4176          2.3E-04           0.0021
     Chloroetheneb                9.5-04            0.13           4.6E-04           0.0312          7.8E-05           0.00014
     1,2-trans-dichloroethene     9.5E-05           7.93           4.6E-05           1.9             7.8E-06           NAc
     Trichloroethene              1.2E-03           2.69           6.0E-04           0.6456          1.0E-04           NAc
     4-methylphenold              1.6E-03           0.19           7.9E-04           0.0456          1.3E-04           0.003
a The contaminant concentrations are due to emissions from the 4.5-Acre Site air strippers only.  The contaminant concentrations 
  were calculated using the ISC-2 dispersion model (EPA 1992).  The NTLs are from the Florida Air Toxics Working List (FDEP 1991).  
  All contaminant concentrations and NTLs are in mg/m3.  The critical receptor for the annual and 24-hour contaminant 
  concentrations is approximately 330 ft west of the 4.5-Acre Site air strippers.  The critical receptor for the 8-hour 
  contaminant concentrations is approximately 330 ft northwest of the 4.5-Acre Site strippers.  
b Dichloromethane is methylene chloride.  Chloroethene is vinyl chloride.  
c There is no annual NTL for 1,2-trans-dichloroethene or trichloroethene.
d 4-methylphenol was evaluated as phenol because there are no NTLs for 4-methylphenol.
NTL - no threat level
ISC-2 - Industrial Source Complex dispersion model 
     Table V.2 shows that all of the calculated contaminant concentrations at the critical
     receptor locations would be below their respective NTLs. The calculated annual
     concentration of dichloromethane (methylene chloride) is 2.3E-04 mg/m3, which is
     slightly greater than the same concentration calculated for emissions from the
     Pinellas Plant (Building 100) itself (2.0E-04 mg/m3 in subsection 4.1.2) (DOE 1992d).
     Combined annual dichloromethane concentrations at the western critical receptor
     location and south Pinellas Plant boundary location due to emissions from the
     Pinellas Plant (Building 100) and the 4.5-Acre Site air strippers are shown in Table
     V.3. The combined dichloromethane concentrations at these two locations are below
     the respective NTLs. The highest combined concentration, 9.0E-04 mg/m3, is at the
     south Pinellas Plant boundary location, which also has the highest calculated
     dichloromethane concentration due to Pinellas Plant (Building 100) emissions
     (subsection 4.1.2) (DOE 1992d). The combined concentration at this location is
     approximately two times greater than the combined concentration at the western
     critical receptor location (less than 4.3E-04 mg/m3). The 4.5-Acre Site air strippers
     would contribute essentially nothing to the combined dichloromethane concentration
     at the south Pinellas Plant boundary location.
     If all or portions of the Pinellas Plant were leased to commercial enterprises, these
     enterprises may involve processes that create air emissions, including emissions of
     VOCs and SVOCs. These air emissions would be documented and regulated under the
     plant's existing Air Emissions Permit (FDEP 1993), and the responsible enterprises
     would obtain any necessary permit modifications or additional permits that would be
     required by the FDEP or PCAQD to demonstrate compliance with air missions
     requirements and to ensure compliance with the NAAQS and the Florida State
     Implementation Plan. Enterprises that might be located at the Pinellas Plant would be
     reviewed by the DOE with respect to their impacts on air emissions, and the DOE
     would conduct additional NEPA review if necessary. Enterprises that would warrant
     substantial permit modifications or new permits would be closely monitored or would
     not be allowed at the plant (DOE 1994d).

5.2.2. No Action

     The no action alternative would consist of continuing the interim corrective action
     for the Northeast Site. Contaminated surficial aquifer groundwater would continue to
     be recovered and treated in the groundwater treatment system for the 4.5-Acre Site.
     Contaminated groundwater from the 4.5-Acre Site, and possibly from the Building 100
     and West Fenceline Areas, would also be treated in this system. The treatment system
     uses an air stripper to remove VOCs and SVOCs from the contaminated groundwater, and
     the air stripper emits VOCs and SVOCs, primarily dichloromethane and chloroethene.
     The existing groundwater treatment system for the 4.5-Acre Site has a water inflow
     capacity of 20 gallons per minute, and the DOE proposes to increase this capacity to
     50 gallons per minute to provide sufficient capacity for the final corrective action
     at the 4.5-Acre Site, the interim corrective action at the Northeast Site, and other
     possible corrective actions (e.g., Building 100 Area). Based on the previous
     analysis of contaminant emissions from two air strippers operating at 50 gallons per
     minute, the use of the 4.5-Acre Site groundwater treatment system for continuing the
     interim corrective action and other corrective actions would not result in
     exceedances of the NTLs for the COCs in the surficial aquifer groundwater.

                      Table V.3. Combined Annual Dichloromethane Concentrations(a)
                                              Concentration at Critical Concentration at
                                                 Property Boundary        South-Property
                  Contamination Source                Location(b)       Boundary Location(c)
       Pinellas Plant (Building 100)                 <2.0E-04               9.0E-04
       4.5-Acre Site air strippers                    2.3E-04               0(d)
       Combined sources                              <4.3E-04               9.0E-04
       a Dichloromethane is methylene chloride. All concentrations are in mg/m3.
       b The critical receptor for the annual contaminant concentrations is approximately 
         330 ft west of the 4.5-Acre Site air strippers.
       c The south Pinellas Plant boundary location has the highest calculated dichloromethane 
         concentration due to Pinellas Plant (Building 100) emissions (subsection 4.1.2) 
         (DOE 1992d).
       d presentation of the air dispersion modeling results on a 330-ft grid shows that there 
         is essentially no dichloromethane contribution from the 4.5-Acre Site air strippers 
         at the south Pinellas Plant boundary location.
       < less than

5.2.3. UV Oxidation

The alternative action of pump-and-treat with UV oxidation would use UV oxidation
instead of air stripping to remove the volatile and semivolatile COCs from the
contaminated surficial aquifer groundwater. Ideally, the UV oxidation process would
degrade the COCs to carbon dioxide, water, and inorganic salts, and there would be
no air emissions depending on the type of UV oxidation system used. However, studies
have shown that certain organic contaminants such as 1,1-dichloroethane are difficult
to oxidize and are removed from the groundwater by air stripping during the UV
oxidation treatment (EPA 1990b). Several of the COCs in Northeast Site groundwater
(e.g., benzene and trichloroethene) would be readily oxidized and easily removed by
UV oxidation. The COC dichloromethane is very similar to 1,1-dichloroethane, and it
is believed that this contaminant would be removed from the surficial aquifer
groundwater by air stripping during the UV oxidation process. Therefore, a
groundwater treatment system with UV oxidation would be expected to produce some air
emissions (DOE 1993c). These air emissions should be less than those produced by air
stripping and should not result in exceedances of the NTLs for the COCs in Northeast
Site groundwater. Depending on the type of UV oxidation system used, the UV oxidation
process could also create emissions such as hydrogen chloride which would require
the use of emissions controls.

5.3. SOILS

5.3.1. Proposed Corrective Action

     The proposed corrective action would result in the temporary disturbance of
     approximately 1.5 acres of soils from the installation of the staging area, a
     groundwater containment measure, groundwater recovery wells, piping, and groundwater
     treatment system. Most of the affected soils would be Made-Land soils, but a small
     area of Myakka Fine Sands would be affected in the western portion of the Northeast
     Site. All of these soils have been disturbed previously by the early dairy farm
     activities, normal Pinellas Plant operations, and by the RFI and interim corrective
     action activities. Additional small areas of soils could be temporarily disturbed in
     the future for the installation of new groundwater recovery and monitoring wells
     (0.01 acre per well) and piping from new recovery wells to the groundwater treatment
     systems (0.03 acre per 100 ft of piping) for the proposed corrective action and
     other corrective actions (e.g., Building 100 Area). All areas disturbed during the
     corrective actions would be restored to as close to their original condition as
     possible and revegetated.

5.3.2. No Action

     The no action alternative would not result in any new disturbance of soils because
     the recovery wells, piping, and groundwater treatment system for the Northeast Site
     interim corrective measure have already been installed. Small areas of soils could be
     temporarily disturbed in the future for the installation of additional groundwater
     recovery and monitoring wells and any associated piping. All disturbed areas would be
     restored to as close to their original condition as possible and revegetated.

5.3.3. UV Oxidation

     This alternative action would require the same equipment and facilities as the
     proposed corrective action except that a UV oxidation unit would be used in the
     groundwater treatment system instead of an air stripper. Therefore, this alternative
     would result in the same temporary disturbance of soils as the proposed corrective
     action. Additional small areas of soils could be temporarily disturbed in the future
     for the installation of new groundwater recovery and monitoring wells and associated
     piping. All disturbed areas would be restored to as close to their original condition
     as possible and revegetated.

5.4. HYDROLOGY

5.4.1. Surface Water

     The proposed corrective action, no action, the UV oxidation alternative action, or
     other corrective actions (e.g., Building 100 Area) would have very little effect on
     surface water at the Northeast Site or Pinellas Plant. Surface disturbance associated
     with corrective action activities (e.g., installation of the groundwater containment
     measure) could cause a slight increase in erosion during heavy precipitation.
     However, the terrain at the Pinellas Plant is generally flat, and the areas disturbed
     during the corrective actions would be restored as soon as possible. The disturbed
     areas would be graded to conform to the surrounding land surface and to avoid the
     ponding of surface runoff, and the areas wou

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