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U.S. ENVIRONMENTAL PROTECTION AGENCY

SUPERFUND PROPOSED PLAN - RECORD OF DECISION AMEMENDMENT

REEVES SOUTHEASTERN GALVANIZING CORP SUPERFUND SITE

OPERABLE UNIT 2 - GROUNDWATER

Tampa, Hillsborough County, Florida August 2013

Introduction The U.S. Environmental Protection Agency (EPA) is proposing changes to the Superfund cleanup at the Reeves Southeastern Galvanizing Corp. Superfund Site (the Site) in Tampa, Florida. The EPA is proposing these changes because the conditions at the Site have changed since the EPA selected the original remedy in 1993. When the remedy at a Superfund site needs to be changed in a fundamental way, the EPA explains and documents the changes in a Record of Decision (ROD) Amendment. This Proposed Plan seeks public comment on the proposed changes. Based on the comments received, a ROD Amendment will be issued finalizing the modified remedy.

The original Operable Unit 2 (OU2) ROD applied to groundwater, was signed in 1993, and selected a remedy that included monitored natural attenuation (MNA) with a contingency remedy of pump and treat to clean up contaminated groundwater at the Site. In 2005, the EPA concluded that MNA was not progressing at an acceptable rate that would result in meeting cleanup levels and achieving the remedial action objectives within a reasonable timeframe. Additionally, EPA concluded that the contingency remedy of pump and treat may not be a practical remedy, given the vertical stratification of metals in groundwater due to the presence of a low-permeability zone. Therefore it was necessary for EPA to consider other remedial altematives. A focused feasibility study (FFS) which evaluated the use of In Situ groundwater treatment via chemically induced precipitation was submitted in July 2011.

The focus of this Proposed Plan is OU2 the groundwater contaminated by historical operations at the Site. This document proposes in situ chemically induced precipitation to treat groundwater to achieve cleanup standards.

Please direct comments or questions to:

Scott Martin Remedial Project Manager

Via email: martia.scott@epa.gov

L'Tonya Spencer, Community Involvement Coordinator Via email: spencer.latonya@epa.gov

Via mail: U.S. EPA, Superfund Remedial Branch

Atlanta Federal Center 61 Forsyth Street SW

Atlanta, Georgia 30303 (800) 435-9233

U.S. EPA will accept written comments on the Proposed Plan during the public comment period of August 30 2013 to September 28, 2013.

PUBLIC MEETING As a pail ofthe public involvement, and during this comment period, the public is invited to request a public meeting. The request can be made by contacting L'Tonya Spencer, Conununity Involvement Coordinator, at

404-562-8463 or Scott Martm, Remedial Project Manager, at 404-562-8916 or 1-800-435-9234. If a meetmg is requested, die EPA will present

its understanding of tlie Site, describe its reasoning for tlie preferred

ahemative presented in this Proposed Plan, and answer any questions.

Greater detail about this site can be found in tlie Administrative Record, available at the following locations:

Brandon Regional Library 619 Vonderburg Drive

Brandon, Florida 33511

and

U.S. EPA Records Center Region 4 61 Forsyth Street, SW

Atlanta, Georgia 30303 Hours: Mon-Fri 7:30 am - 4:30 pm

Phone (404) 562-8835

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The EPA seeks public review and comments on this Proposed Plan. The EPA will accept public comments for at least 30 days from August 30, 2013 to September 28, 2013. Comments may be submitted by mail, email, or by phone. U.S. EPA will accept written comments on the Proposed Plan during the public comment period. As a part of the public involvement, and during this comment period, the public is invited to request a public meeting. The request can be made by contacting L'Tonya Spencer, Community Involvement Coordinator, at 404-562-8463 or Scott Martin, Remedial Project Manager, at 404-562-8965 or 1-800-435-9234. If a meeting is requested, the EPA will present its understanding of the Site, describe its reasoning for the preferred alternative presented in this Proposed Plan, and answer any questions.

The EPA is the lead agency on this site and is supported by the Florida Department of Environmental Protection (FDEP). The EPA and the FDEP will consider comments submitted during the public comment period, and select one of the remedial altematives as the final remedy to address the groundwater contamination at the Site. The final remedy will be selected and documented in a ROD Amendment. The ROD Amendment will be issued via mail, electronically, and placed in a local information repository. This process is part of the EPA's requirements under Section 117 of the Comprehensive Environmental Response, Comp­ensation and Liability Act (CERCLA) and Section 300.435(c)(2)(ii) of the National Contingency Plan (NCP).

Site Background

The Site is located on the north side of State Road 574, approximately 1,200 feet west of Falkenburg Road in central Hillsborough County, Florida. The Site facility was formerly operated by Reeves Southeastern Galvanizing Corp. (Reeves) and is currently operated by Industrial Galvanizers Southeast (IG), which has leased the Site since March 1, 1996. IG leases and operates on approximately 10.09 acres ofthe 17.36-acre Site. The North Wetland is located immediately west of the Site and is approximately 1.75 acres in size, located within the maintained right-of-way of an electrical-transmission line. The Unnamed Creek borders the western side of the Site and traverses diagonally in a north-northeasterly direction across the northwest comer of the Site.

The land use in the vicinity of the Site is mixed-commercial, light-manufacturing, and office buildings. The nearest residential property is more than 0.25 mile southeast of the Site. The North Wetland lies within a power-line easement west of the Site. The Unnamed Creek bisects vacant land north of the Site and flows parallel to the power-line easement. Two federal Superfund sites —Peak Oil Superfund Site and the Bay Drum Superfund Site— are located south of the Site. A facility operated by Master Halco (formerly the Reeves Southeastem Wire, or SEW, operation) is also located to the south of the Site. The SEW Site was formerly operated by the same company that operated the SEG Site, and both were listed on the EPA's National Priorities List (NPL). The SEW Site has received a "No Further Action" determination. See Figure 1 for Site Layout.

Site History The Reeves Southeastem Galvanizing facility was originally built and operated as Acme Plating and Galvanizing Company in the mid-to-late 1960s. In 1970, the facility was acquired by Metal Coatings, Inc., which merged into the Southeastern Galvanizing Corporation in 1971. Through internal reorgan­izations, Southeastem Galvanizing Corporation became the Southeastem Galvanizing Division of Reeves Southeastem Corporation. Reeves South­eastem Corporation operated at the Site until March 1996, when IG bought the Reeves Southeastem Galvanizing assets.

The metal-coating operations conducted by Reeves Southeastern Galvanizing generated process wastewater that was discharged into two evaporation/percolation ponds until 1982, when a wastewater pretreatment system was installed. At that time the facility began treating its wastewater in a lined pond constructed to the east of the two evaporation/percolation ponds. Following treat­ment, the wastewater was discharged to the local publicly owned treatment works (POTW).

Regulatory History The EPA conducted a site investigation in 1981 that indicated the presence of elevated concentrations of metals in surface water and groundwater at the Site. In August 1982, the FDEP (then the Florida Department of Environmental Regulation) conducted

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a survey of the extent of contaminants in soil and groundwater at the Site, and determined that arsenic, cadmium, chromium, lead, nickel, and zinc were Contaminants of Concern (COCs). This survey resulted in the placement of the Site on the NPL in 1982.

In 1985 a terrain-conductivity survey at the Site was conducted using electromagnetic-induction technology, which indicated possible high con­centrations of metals in shallow groundwater.

In 1988, Reeves and a group of potentially responsible parties for the adjacent Peak Oil/Bay Drum Superfund site signed individual Administrative Orders of Consent (AOCs) to perform source characterization Remedial Investigation and Feasibility Studies (RI/FS) at their respective sites and a joint AOC for the area-wide groundwater RI/FS. The Peak Oil/Bay Dmm Superfund site, which is currently undergoing remedial activities to address releases of organic constituents to groundwater and surface water, is located immediately south of the Site across Broadway Avenue. The EPA conducted a Wetland Impact Study (WIS) in 1989 for the North Wetland, which is located west ofthe Site.

Operable Units

Following delineation of affected soil and groundwater and completion of the Site source and area-wide RIs, respectively, the EPA divided the Site into three Operable Units to manage the contamination at the affected media.

OUl (addresses contaminated soils and sediments),

OU2 (addresses contamination in the northern surficial groundwater), and

OU3 (addresses the North Wetland and Uimamed Creek).

OUl The remedy for OUl was selected in September 1993. Implementation of the OUl remedy began in May 1996 and was completed in August 1997. Components of the OUl remedial action included abandoning various monitoring wells, dismantling waste water-pre treatment equipment, excavating acidic soil affected with metals from various locations at the Site, dredging the ponds, and excavating the lined basin. Before excavated areas

were backfilled, vertical and horizontal confirmatory soil sampling was conducted.

0U2 The remedy for OU2 was selected in September 1993 and included natural attenuation of the Northern Surficial Aquifer, installation of additional monitor wells, prevention of discharge of groundwater to surface water, and completion of remedial design for the contingency remedy (main components of the remedy). The ROD for OU 2 also included the following criteria (referred to as modifications) that provided parameters by which other remedial components would be implemented:

Modification One: establishment of "Time Zero Values" of the COCs (arsenic, cadmium, chromium, lead, nickel, and zinc) to evaluate whether the levels of contaminants of concern (COCs) have been reduced to either below the selected cleanup levels, or at least 50 percent of the "Time Zero Values" within 2.6 years of completion of OUl remedial action;

Modification Two: preparation of a contingency remedy of groundwater extraction and treatment to be implemented in the event the levels of the COCs are not being reduced; and

Modification Three: construction of an engineering barrier to prevent the discharge of the northern surficial aquifer into the Unnamed Creek.

Modification One stipulates that MNA is not working if the concentrations ofthe COCs are not reduced to cleanup levels established in the OU2 ROD, or to the 50-percent Time Zero Values^ whichever is greater, within 2.6 years of completion of the OUl remedial action, and that the contingency remedy of groundwater extraction and treatment should be implemented. The 2.6-year timeframe was based on modeling conducted in 1992 as part ofthe Area-Wide Remedial Investigation. The modeling evaluated how long it might take for COC concentrations in the surficial groundwater to reduce to the cleanup levels established in the 0U2 ROD through advective flushing (i.e., no retardation), compared to how long it would take if an active extraction-and-treatment system were in operation. The model predicted it

^The 50-percent Time Zero Value means 50 percent ofthe time-zero starting point concentrations as established by the January 19, 1994, sampling ofthe 0U2 compliance monitoring wells.

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would take 7.6 years for COCs to reach the cleanup levels if natural-attenuation processes alone were used.

In accordance with the requirements of Modification One, Reeves submitted the Modification One Report (MOR) in November 2004 to document the progression of natural attenuation. The OU2 Statement of Work provided that the EPA would consider the information presented in the MOR in making its decision concerning the effectiveness of the OU2 remedy and the need to implement the contingent remedy. The MOR showed that natural attenuation was occurring based on the data that demonstrated plume stability and decreasing concentration trends in performance monitoring wells. In a letter dated April 2005, the EPA concluded that natural attenuation was occurring, but not proceeding at a rate that would achieve cleanup levels in a reasonable timeframe. Although the contingent remedy for groundwater was specified in the OU2 ROD, EPA concluded that the contingent remedy may not be the most appropriate technology to remediate the metals in groundwater and that a more effective alternative, such as in situ groundwater treatment, should be evaluated. Reeves requested that MNA continue and be further evaluated after the 2006 five-year review was completed. Subsequently, Reeves began to evaluate alternate technologies and submitted a focused feasibility study (FFS) in 2011.

Modifications Two and Three ofthe OU2 ROD have been completed. The design of a groundwater pump and treat system has been completed, and approved as a contingency if deemed necessary. In addition, the design of an engineering barrier to prevent the discharge of the northern surficial aquifer into the Unnamed Creek was approved by the EPA and Hillsborough County and was constructed in January 2004.

OU3 The remedy for OU3 was selected in June 1994 which determined that No Action was needed to address contamination for the North Wetland and the Unnamed Creek. The remedy included periodic ecological assessment of the North Wetland and the Unnamed Creek for a period of eight years, to be extended beyond eight years if the OU2 remedy were extended due to the cleanup levels not being met.

Site Characteristics The groundwater system beneath the Site consists of two major water-bearing units: a surficial aquifer and the Floridan Aquifer system. The surficial aquifer is defined as a Class IIB aquifer, which means it is considered a potential drinking water source.

The surficial aquifer is hydraulically connected to the wetlands near the Site, and groundwater flow direction varies seasonally. Water levels also fluctuate seasonally and change rapidly in response to rainfall and other natural influences. Groundwater historically might have discharged seasonally to the Unnamed Creek, but construction of a stormwater conveyance structure in 2004 has mitigated this potential pathway.

Separating the surficial aquifer from the underlying Floridan Aquifer is the Hawthorn formation, a clayey, low-permeability layer. Although the Floridan Aquifer flows to the west-southwest at a regional scale, the flow shifts toward the northwest in the vicinity of the Site. This is thought to be due to the proximity ofthe Site to the Tampa Bypass Canal, which reportedly cuts into the low-permeability Hawthorn formation and reaches the upper Floridan Aquifer in several places. The Floridan Aquifer is the primary source of drinking water and water for industrial use in Hillsborough County. However, there are no permitted drinking water wells in the vicinity of the Site, and the area has been designated as a Florida Ground Water Delineated Area, which requires restriction of groundwater access.

Sand Zone The surficial aquifer consists of two connected formations, a Sand Zone and a Transitional Zone. The Sand Zone is characterized by higher porosity and groundwater flow, while the Transition Zone is a tighter formation that still contains groundwater. A map of the COCs detected in groundwater exceeding the 1993 ROD cleanup levels is presented on Figure 2. This figure demonstrates that 1993 ROD cleanup levels are exceeded in Sand Zone groundwater over an area of approximately 234,000 ft . There are two distinct areas of affected groundwater in the Sand Zone; one near the former ponds and one near the former process building. The extent of zinc in groundwater exceeding the cleanup level is the largest ofthe COCs.

The FDEP natural attenuation default concentrations (NADCs) were compared to groundwater data to

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identify potential high-concentration zones in the Sand Zone. The NADCs are generally ten times the COC cleanup levels, with the exception of zinc, which is five times its cleanup level. The high-concentration zones (or groundwater exceeding the NADCs) are identified on Figure 2. The area of high-concentration zones is approximately 16,000 ft , which is approximately 7 percent of the affected groundwater area exceeding the 1993 ROD cleanup levels.

Transition Zone Site characterization indicates that metal concentrations are higher in groundwater in the Transition Zone than in the overlying Sand Zone. This supports the contention that metals being retained in the Transition Zone are less influenced by flushing than in the Sand Zone, where natural attenuation processes appear to have reduced metal concentrations. Transition Zone groundwater data were compiled and a compliance map of the COCs exceeding the cleanup levels was generated (Figure 3). 1993 ROD cleanup levels are exceeded in Sand Zone groundwater over an area of approximately 300,000 tV. The extent of zinc in groundwater exceeding the cleanup levels is the largest of the COCs (Figure 3).

The map also shows the high-concentration zones (or groundwater exceeding the NADCs) in the Transition Zone (Figure 3). The area of "high-concentration zones" is approximately 128,000 ft , which is approximately 40 percent ofthe affected groundwater area exceeding the 1993 ROD cleanup levels. In comparison with the Sand Zone, the larger per­centage of the overall impacts being classified as high-concentration in the Transition Zone implies that natural attenuation is less effective. Since the Transition Zone is characterized by silt and clay and the primary natural attenuation mechanism for metals is dilution, these reasons further explain the difference between the lack of progress of MNA and the original model.

The Transition Zone accounts for approximately 40 percent of the total volume of affected groundwater, but contains more than 95 percent of the mass of COCs. Because concentration of COCs is much higher in the Transition Zone, the controlling factor in the selection of remedial technologies will be the potential for mass flux reduction from the Transition Zone to achieve the cleanup levels. Floridan Aquifer

Historical monitoring of the Floridan Aquifer at the Site has indicated that COCs do not exceed 1993 ROD cleanup levels in the Floridan Aquifer. Historical data demonstrate that metals have not adversely impacted the Floridan Aquifer, likely due to the separation of the surficial groundwater from the Floridan Aquifer by the confining Hawthorn Group aquitard. However, given the identification of subsurface depressions in the Hawthorn surface and the potential for areas of thinner confining clay to act as conduits for contamination, a Floridan monitoring well was installed in 2007 to evaluate potential vertical migration. To date, monitoring indicates that COC concentrations in the Floridan Aquifer are below the cleanup levels.

Scope and Role The focus of this Proposed Plan is OU2, the groundwater contaminated by historical operations at the Site. This document proposes to modify the OU2 remedy selected in 1993 to in situ chemically induced precipitation to treat groundwater to achieve cleanup levels, swale lining, monitored natural attenuation, and institutional controls.

As detailed in the Site Background, the remedial actions for OUl and OU3 have been completed. OUl addressed contaminated soils and sediments. Cleanup activities for OUl included abandoning various monitoring wells, dis-mantling wastewater-pretreatment equipment, excavating soils, dredging ponds, and backfill with clean material. The OU3 ROD selected a No Action/Monitoring for the North Wetland and the Unnamed Creek

Summary of Site Risks A Risk Assessment is an evaluation of whether existing or future exposure to Site contamination could pose an unacceptable risk to people or the environment. The EPA estimates the potential risks if no action would be taken to address contamination at the Site. The Risk Assessment serves as the baseline for determining whether a cleanup is necessary.

Two baseline risk assessments were performed for the Site. The first baseline risk assessment addressed OUl source materials and found that human health risks associated with exposure to contaminated soil

and sediment fell well within EPA's acceptable risk range for Superfund sites (10" to lO"' ). EPA also performed an area-wide wetland impact study which investigated environmental toxicity for five area

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wetlands. The study found site-related compounds at concentrations above background levels in sediment and surface water in the North Wetland and Unnamed Creek.

The OU2 baseline risk assessment was performed as part of the area-wide groundwater RI/FS. This assessment did not address current exposure, since on-site groundwater was not being used and area businesses and residences are all serviced by the Tampa Water Department. However, the risks associated with possible future exposure for workers or residents exceeded the risk range for both the surficial aquifer and the Floridan Aquifer, which is the source of municipal water supplies in the area. For this reason, actual or threatened releases of hazardous substances from the site soil and sediment into the groundwater were determined to present an imminent and substantial endangerment to public health, welfare and the environment, if not addressed by remedial action. The endangerment was defined as the potential for further degradation of the area-wide groundwater via leaching of contaminants from the contaminated Site soil.

In addition, all site-related contaminants were detected in the northern surficial aquifer at concentrations exceeding either maximum contaminant levels (MCLs) or acceptable health-based numbers. The northern surficial aquifer has been classified as a Class IIB, or potential drinking water source, aquifer and a goal of EPA's Superfund program is to return usable and potentially usable groundwaters to their beneficial uses within a reasonable timeframe. MCLs and health-based numbers are considered appropriate cleanup levels for Class I and II aquifers. Therefore, any exceedances of these preliminary cleanup levels were considered as appropriate justification to take action to return the groundwater to its beneficial use.

It is the EPA's current judgment that the Preferred Alternative identified in this Proposed Plan (see Summary of the Preferred Alternative, below) is necessary to protect human health from actual or threatened releases of hazardous substances into the environment.

Remedial Action Objectives The proposed Remedial Action Objectives (RAOs) include the media-specific standards and points of compliance for the Site. An identification and evaluation of applicable or relevant and appropriate requirements (ARARs) was conducted during the original OU2 Record of Decision (ROD) development;. The cleanup levels for the Site groundwater are the cleanup levels specified in the OU2 ROD, with the exception of arsenic. The MCL for arsenic has changed since the original ROD from 50 (ig/L to 10 ug/L. Groundwater is the affected environmental medium, and the COCs in accordance with the OU2 ROD are arsenic, cadmium, chromium, lead, nickel, and zinc. The RAOs for the Site are:

• Prevent human exposure to contaminated groundwater.

• Reduce COCs in groundwater such that natural attenuation mechanisms will achieve cleanup levels within reasonable timeframes.

• Prevent groundwater discharge to surface water (including the drainage swales) where COC concentrations in groundwater exceed surface water standards.

Table 1 Site Specific Cleanup Levels

Contaminant

Arsenic

Cadmium

Chromium (total)

Lead

Nickel

Zinc

Cleanup Level 1 (pg/LD

10

5

100

15

100

10,000

Class III SWC2 (pg/L)

10

0.6

11

12.3

128.4

295.3

^Groundwater cleanup levels from GCTLs Table 1, Chapter 62-777, FAC. ^Class III surface water criteria calculated from Chapter 62-302 FAC using hardness data from S-2 (290 mg/L) collected August, 2007. tjg/L = microgram per liter

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Summary of Remedial Alternatives For the Reeves Southeastem Site, the following remedial alternatives were evaluated:

Alternative 1

Alternative 2

Alternative 3

In Situ Groundwater Treatment via Chemically Induced Precipitation, Monitored Natural Attenuation, Swale Lining, and Institutional Controls

Monitored Natural Attenuation

Groundwater Extraction and Treatment

Descriptions ofthe three altematives are presented below.

Alternative 1: In Situ HCSZ/HCTZ Treatment/Swale-Lining/Monltored Natural Attenuation/Institutional Controls

Capital Cost: $1,109,000 Estimated Present Worth Costs: 2,827,000 Estimate Time to Achieve RAOs: 15 years

Alternative 1 consists of in situ treatment ofthe High Concentration Sand Zonc/Tfigh Concentration Transition Zone (HCSZ/HCTZ), implementing institutional controls, and continuing MNA. Areas of groundwater where COC concentrations exceed the FDEP NADC are referenced as high concentration zones. Alternative 1 comprises short-term, active remediation and long-term passive remedial technologies. Specifically, Ahemative 1 includes the active treatment ofthe HCSZ and HCTZ. This alternative also includes swale-lining to eliminate discharges of groundwater to surface water, as well as institutional controls to eliminate potential human health exposure pathways during the period between the completion of active remediation and the attainment of cleanup levels through passive remediation, documented through MNA.

The goal of in situ treatment would be to lower dissolved COC concentrations to below cleanup levels within the HCSZ and HCTZ via in situ chemically induced precipitation. In locations of subsurface depressions on the Hawthorn, and thick Transition Zones, adequate hydraulic flushing is limited and has resulted in accumulation of

approximately 95 percent of the dissolved phase mass. Biasing sulfide precipitation to these areas will provide the most efficient in situ treatment and reduce mass flux from the Transition Zone to the Sand Zone to facilitate more rapid natural attenuation. Without a continued source of dissolved phase COCs, dilution/sorption/'precipitation mech­anisms will reduce residual dissolved phase concentrations to below cleanup levels. Natural attenuation is part of Alternative 1, but will not be relied upon in high concentration areas where NADCs are exceeded.

The total treatment areas ofthe HCSZ and HCTZ are approximately 16,000 and 128,000 ft , respectively. In situ treatment of high-concentration zones would be implemented using injection of a potential titrant and chemical reductant solution at concentrations refined during further treatability and field testing during the remedial design.

Concurrent with in situ treatment, the drainage swales would be lined with concrete, or other low-permeability material, to prevent the interaction between groundwater and surface water. To eliminate surface water infiltration and groundwater discharge, the shallow drainage swales can be lined to provide separation ofthe surface water and groundwater. This engineering control is important while the low concentration portions of the plume attenuate following treatment ofthe high concentration zones. With the construction of the liner and previous constmction of the stormwater-conveyance structure, the limited pathway for groundwater seepage to surface water will be eliminated.

A performance monitoring program will be implemented to evaluate the effectiveness of in situ treatment and to evaluate whether COC concentrations have been reduced to below cleanup levels. A number of impacted and un-impacted Sand Zone and Transition Zone wells have been carefully selected to make up the monitoring well network. If the monitoring indicates that COC concentrations are below cleanup levels, then the MNA period of Ahemative 1 will commence. If after one year COC concentrations are not below NADC, then a contingent injection event will be implemented to accelerate the attenuation processes, followed by an additional year of performance monitoring. During the MNA portion of Alternative 1, if COC concentrations are not reducing in agreement with cleanup timeframe calculations from the remedial

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design, then additional injection events may be considered at locations providing the greatest remedial benefit. For cost estimating, it is assumed that two contingent injection events will be required to reduce the COCs below the NADCs in the Transition Zone.

Institutional controls would be implemented to eliminate potential human health exposure pathways during active and passive remediation. Institutional controls include various physical, operational, and legal restrictions to the Site. Current existing institutional controls preventing use of groundwater include the Hillsborough County ordinance requiring connection to public water lines and FDEP restrictions on groundwater well installations in the area.

Alternative 2: Monitored Natural Attenuation /Institutional Controls Direct and Indirect Capital Cost: $133,800 Estimated Net Present Value: $1,365,000 Estimate Time to Achieve RAOs: 30, or more, years

MNA is the currently selected remedy for OU2, and this alternative was included in this FFS as a basis of comparison to more aggressive remedial altematives. The monitoring parameters include COC concentrations (primarily dissolved metals) and key geochemical indicating parameters, such as pH, Oxidation-Reduction Potential (ORP), sulfide, and ferrous iron. MNA would be easily implementable with limited enviromnental disturbance as a large monitoring well network is currently available. As indicated by historical data, MNA may not be able to achieve the groundwater cleanup levels in a reasonable timeframe. Institutional controls would be implemented to eliminate potential human health exposure pathways during active and passive remediation. Institutional controls include various physical, operational, and legal restrictions to the Site. Current existing institutional controls preventing use of groundwater include the Hillsborough County ordinance requiring connection to public water lines and FDEP delineated area limiting groundwater well installations in the area.

Alternative 3: Groundwater and Treatment/Institutional Controls Direct and Indirect Capital Cost: $2,130,000 Estimated Net Present Value: $9,052,000 Estimate Time to Achieve RAOs: 30, or more, years

Groundwater extraction and treatment (GWET) is currently the contingency remedy for OU2. In 2005 EPA determined that pump and treat to clean up contaminated groundwater may not be practical and that another remedial alternative should be considered. Altemative 3 is designed to control the migration of the dissolved COCs while physically removing the contamination from the subsurface. Extraction wells will be biased to areas of thick Transition Zone material and subsurface depressions. Ex situ treatment of extracted groundwater will include chemical precipitation and potentially flocculation followed by sedimentation and off-site disposal. GWET has the benefit of removing COCs, in contrast with Altemative 1, which relies upon the stability of metal sulfides. However, the subsurface Site characteristics may limit effectiveness of Altemative 3, as GWET will be diffusion limited in fine grained stratigraphy and will require long-term operation to achieve cleanup levels. Currently implemented institutional controls will be enforced and augmented where necessary to support the RAOs. Altemative 3 will operate for more than 30 years.

Evaluation of Alternatives Nine criteria are used to evaluate the remedial alternatives individually and against each other in order to select a remedy. These criteria are:

1. Overall protection of human health and the environment

2. Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)

3. Long-term effectiveness and permanence 4. Reduction of Toxicity, Mobility, or Volume

(T/M/V) through treatment 5. Short-term effectiveness 6. Implementability 7. Cost 8. State Acceptance 9. Community Acceptance

The nine evaluation criteria are divided into three groups based on the function of the criteria in remedy selection. The first two criteria are threshold criteria and must be satisfied for a remedial altemative to be considered viable. Criteria 3 through 7 are balancing criteria applied to those alternatives which satisfy tlie two threshold criteria. The last two criteria are modifying

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criteria. State and community acceptance is evaluated by the EPA during the public comment period ofthe Proposed Plan. EPA prepares a responsiveness summary that addresses comments received and will be part ofthe ROD Amendment.

1. Overall Protection of Human Health and The Environment Institutional controls associated with each altemative will be protective of human receptors. Each alternative includes components that reduce or remove dissolved-COC mass. There are no short-term or cross media impacts associated with the selected alternatives.

2. Compliance with ARARs All three alternatives would comply with ARARs and TBCs. Alternative 1 provides the fastest altemative to achieving ARARs and TBCs, because its treatment mechanism is more efficient than the other altematives. Altemative 1 expects to reach ARARs and TBCs in 15 years, whereas the other alternatives are expected to take more than 30 years. Alternative 3 will generate large quantities of solid waste and could potentially generate hazardous waste sludge from the groundwater-treatment process.

3. Long-Term Effectiveness and Permanence Alternative 3 uses physical removal of the COCs so when cleanup levels are achieved the remediation is expected to be permanent. However, given the sorptive nature of the COCs and the impermeable hydrogeology, it is expected that Altemative 3 would present challenges in achieving cleanup levels. Alternative 1 will attain RAOs by reducing COC concentrations to below cleanup levels. Metal precipitates are stable and are expected to remain insoluble. Additionally, institutional controls preventing potential exposure to receptors is a component of every alternative. Therefore, in comparison Altemative 1 presents a lower magnitude of remaining risks, less frequent long term monitoring, less operation and maintenance, and less of a need for replacement of technical components.

4. Reduction of Toxicity, Mobility, and Volume through Treatment Alternative 3 represents the greatest reduction of toxicity, mobility, and volume through treatment of the three altematives. None of the alternatives destroy COCs, as destruction of inorganic COCs is not possible. The remedial effects of Alternative 3 are less reversible than Altemative 1, as

CRITERIA FOR EVALUATING REMEDIAL ALTERNATIVES In selecting a preferred cleanup alternative, EPA uses the following criteria to evaluate the alternatives from the Feasibility Study (FS). The first two criteria are threshold criteria and must be met for an option to be considered further. The next five are balancing criteriaforweighing the merits of those that meet the threshold criteria. The final two criteria are used to modify EPA's proposed plan based on state and community input.

1. Overall Protection of Human Health and the Environment - Eliminates, reduces, or controls health and environmental threats through institutional or engineering controls or treatment.

2. Compliance with Applicable or Relevant and Appropriate Requirements (ARARs) - Compliance with Federal/State standards and requirements that pertain to the site or whether a waiver is justified.

3. Implementability - Technical feasibility and administrative ease of conducting a remedy, including factors such as availability of services.

4. Short-Term Effectiveness - Length of time to achieve protection and potential impact of implementation. 5. Long-Term Effectiveness and Permanence - Protection of people and environment after cleanup is

complete.

6. Reduce Toxicity, Mobility, or Volume by Treatment - Evaluates the alternative's use of treatment to reduce the harmful effects of principal contaminants and their ability to move in the environment.

7. Cost - Benefits weighed against cost. 8. State Acceptance-Consideration of state's opinion of the preferred alternative(s). 9. Community Acceptance-Consideration of public comments on the Proposed Plan.

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precipitated sulfide minerals can be susceptible to remobilization under extreme acidic and/or oxidizing conditions. These conditions are not anticipated, but for comparison purposes removing the COCs reduces the potential future mobility and toxicity more than precipitation. Altemative 3 will require prolonged operation to reach cleanup levels.

5. Short-Term Effectiveness Alternative 1 presents the most effective altemative in terms of short term effectiveness. There are no risks to the community as part of Alternatives 1 or 2. Alternative 3 would require off-site disposal of solids, which would lead to transportation of impacts off site to a proper disposal facility. Altematives 1 and 2 present the least amount of risk to workers, as both are in situ strategies. Altemative 3 would require extensive underground piping through IG's processes that could expose workers to impacts. Alternatives 1 and 3 present the greatest potential for enviromnental impacts. Altemative 1 has a swale lining component that could upset the ecosystem, and will require habitat management. Altemative 3 will require trenching and evasive infrastructure installation. Alternative 1 presents the best opportunity to reach RAOs in a reasonable time frame (15 years), whereas Altematives 2 and 3 will have no short-term effect on COCs in the Transition Zone, and may require greater than 30 years of operation to achieve RAOs.

6. Implementability The equipment and resources required to implement the three alternatives are readily available. Altemative 2 is the most implementable, followed by Alternatives 1 and 3. A well network is already present and would require minor additions to make it sufficient for the MNA strategy that is part of Alternative 2. Alternatives 1 and 3 would require negotiating long term access agreements for monitoring and maintaining components of the respective remedial altematives. The GWET alternative presents the most implementation issues due to the difficulties in installation and operation of a metals-removal pretreatment system given IG's current Site operations. Altemative 3 would also generate considerable waste that would have to be transported off site for disposal.

7. Cost Altemative 3 has the highest capital cost, average yearly operation and management (OM&M) cost, and present worth. Alternative 1 has the second highest

capital and present worth cost, but Altemative 2 has the second highest OM&M cost. 8. State/Support Agency Acceptance FDEP has been involved in the process and has expressed support for the Preferred Alternative, Alternative 1. State support for the proposed plan is anticipated.

9. Community Acceptance Community acceptance of the Preferred Altemative will be evaluated after the Proposed Plan cormnent period ends and will be described in the Responsiveness Summary of the ROD Amendment for OU2.

Summary of the Preferred Alternative Alternative 1 consists of in situ treatment of the HCSZ/HCTZ, lining the shallow drainage swales, implementing institutional controls, and monitored natural attenuation. Altemative 1 comprises short-term, active remediation and long-term passive remedial technologies. Specifically, Altemative 1 includes the active treatment of the HCSZ and HCTZ, biased to depression areas in the Hawthorn, which have been identified as the high-concentration zones. This alternative also includes swale-lining to eliminate discharges of groundwater to surface water, as well as institutional controls to eliminate potential human health exposure pathways during the period between the completion of active remediation and the attainment of cleanup levels through passive remediation.

The goal of in situ treatment would be to lower dissolved-COC concentrations to below cleanup levels within the HCSZ and HCTZ. In locations of subsurface depressions on the Hawthorn and thick Transition Zones, adequate hydraulic flushing is limited and has resulted in accumulation of approximately 95 percent of the dissolved phase mass. Biasing sulfide precipitation to these areas will provide the most efficient in situ treatment and reduce mass flux from the Transition Zone to the Sand Zone to facilitate more rapid natural attenuation. Without a continued source of dissolved phase COCs, dilution/sorpti on/precipitation mech­anisms will reduce residual dissolved phase concentrations to below cleanup levels. MNA is part of Alternative 1, but will not be relied upon in areas where NADCs are exceeded.

The EPA expects the Preferred Alternative to satisfy the following statutory requirements of CERCLA

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Section 121(b): (1) be protective of human health and the environment; (2) comply with ARARs; (3) be cost-effective; (4) utilize permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable; and (5) satisfy the preference for treatment as a principal element, or explain why the preference for treatment will not be met.

Community Participation The EPA and FDEP provide information regarding the cleanup of the Reeves Southeastern Galvanizing

Corp. Superfund Site to the public through public meetings, the Administrative Record file for the Site, and announcements published in the Tampa Bay Times Newspaper. The EPA and the state encourage the public to gain a more comprehensive understanding ofthe Site and the Superfund activities that have been conducted at the Site.

The dates for the public comment period, how to request a public meeting, and the locations of the Administrative Record files, are provided on the first page of this Proposed Plan.

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/1C\ GLOSSARY

Administrative Record: All documents which the EPA considered or relied on in selecting the response action at a Superfund site, culminating in the record of decision for remedial action or, an action memorandum for removal actions, usually placed in the information repository near the Site.

Applicable or Relevant and Appropriate Requirements (ARARs): Federal and more stringent State environmental laws and regulations that pertain to the contamination, location, or remedial actions planned at a Superfund site.

Aquifer: An underground geologic formation, or group of formations, containing water, especially as a source of groundwater for wells, springs, etc.

Cleanup: Actions taken to deal with a release or threat of release of a hazardous substance that could affect humans and/or the environment. The term "cleanup" is sometimes used interchangeably with the terms remedial action, removal action, response action, or corrective action.

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA): Also known as Superfund, is a federal law passed in 1980 and modified in 1986 by the Superfund Amendment and Reauthorization Act (SARA). The act created a trust fund to investigate and cleanup abandoned or uncontrolled hazardous waste sites.

Environmental Protection Agency (EPA): The United States Environmental Protection Agency.

Feasibility Study (FS): Analysis ofthe practicability of potential cleanup altematives for a Superfund site. It usually starts after the remedial investigation. Together, they are commonly referred to as the RI/FS.

Groundwater: The supply of fresh water found beneath the Earth's surface, usually in aquifers, which supply wells and springs. Because groundwater is a major source of drinking water, there is growing concern over contamination from leaching agricultural or industrial pollutants or leaking underground storage tanks.

Information Repository; In the Superfund program, a file that contains accurate, up-to-date documents on a Superfund site. The file is usually located in a public building (school, library, or city hall) convenient for local residents.

In-situ: In its original place; unmoved unexcavated; remaining in the subsurface.

Institutional Controls: Restriction that prevents the owner from inappropriately developing the property. The restriction could be implemented as a "deed Restriction" and is designed to prevent harm to workers or potential residential development.

Maximum Contaminant Level (MCL): The maximum permissible level of a contaminant in water delivered to any user of a public system. MCLs are enforceable standards.

Monitoring: The periodic or continuous surveillance or testing to determine the level of pollutants in various media.

Monitoring Well: A well drilled at or near a hazardous waste management facility or a Superfund site to collect groundwater samples for the purpose of physical, chemical or biological analysis to determine the amounts, types and distribution of contaminants in the groundwater beneath the Site.

National Contingency Plan (NCP): The federal regulation that guides determination ofthe sites to be corrected under both the Superfund program and the program to prevent or control spills into surface waters or elsewhere.

National Priorities List (NPL): The EPA's list ofthe most serious unconttolled or abandoned hazardous waste sites identified for possible long-term remedial action under Superfund. The list is based primarily on the score a site receives from the Hazard Ranking System. The EPA is required to update the NPL at least once a year.

Operable Units (OUs): Term for each of a number of separate activities undertaken as part of a Superfund site cleanup. A typical operable unit would be removal of drums and tanks from the surface of a site.

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Proposed Plan (PP): A plan for a site cleanup that is available to the public for comment.

Public Comment Period: The time allowed for the public to express its views and concerns regarding an action by the EPA (e.g. a Federal Register Notice of proposed rule-making, apubhc notice of a draft permit, or a Notice of Intent to Deny).

Record of Decision (ROD): A public document that explains which cleanup alternative(s) will be used to clean up a Superfund site. The ROD is based on information and technical analysis generated during the remedial investigation/feasibility study and consideration of pubhc comments.

Remedial Action (RA): The actual construction or implementation phase of a Superfund site cleanup that follows remedial design.

Remedial Action Objectives (RAOs): Provide a general description of what the cleanup will accomplish (e.g., restoration of groundwater to drinking water levels). These goals typically serve as the design basis for many ofthe remedial alternatives.

Remedial Investigation (RI): An in-depth study designed to gather data needed to determine the nature and extent of contamination at a Superfund site; establish site cleanup criteria; identify preliminary alternatives for remedial action; and support technical and cost analyses of alternatives. The remedial investigation is usually done with the feasibility study. Together they are usually referred to as the RI/FS.

Remedial Project Manager (RPM): The EPA or state official responsible for overseeing on-site remedial action.

Response Action: 1. Generic tenn for actions taken in response to an actual or potential health-threatening environmental event such as spills, sudden releases, and asbestos abatement/management problems. 2. A CERCLA-authorized action involving either a short-term removal action or a long-term removal response. This may include but is not limited to: removing hazardous materials from a site to an EPA-approved hazardous waste facility for treatment, containment or treating the waste on-site, identifying and removing the sources of ground-water contamination and halting further migration of contaminants. 3. Any ofthe following actions taken in school buildings in response to AHERA to reduce the risk of exposure to asbestos: removal, encapsulation, enclosure, repair, and operations and maintenance.

Responsible Party (RP): Any individual (s) or company (s) (such as owner, operator, ttansporter, or generator) potentially responsible for, or contributing to, contamination at a CERCLA site. Whenever possible, the EPA requires PRPs, through administrative and legal actions, to cleanup hazardous waste sites that they have contaminated.

Responsiveness Summary: A summary of oral and written comments received by the EPA during a comment period on key EPA documents, and the EPA's responses to those comments. The responsiveness summary is a key part ofthe ROD, highlighting community concems for EPA decision-makers.

Risk Assessment: A qualitative and quantitative evaluation performed ofthe risk posed to human health and/or the environment by

the actual or potential presence and/or use of specific pollutants.

Sediment: Topsoil, sand, and minerals washed from the land into water, usually after rain or snow melt.

Superfund: The program operated under the legislative authority of CERCLA and SARA that funds and carries out the EPA's solid

waste emergency and long-term removal and remedial activities. These activities include establishing the National Priorities List, investigating sites for inclusion on the list, determining their priority, and conducting and/or supervising cleanup and other remedial actions. Wetlands: An area that is saturated by surface or groundwater with vegetation adapted for life under those soil conditions, as swamps, bogs, fens, marshes, and estuaries.

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USE THIS SPACE TO WRITE YOUR COMMENTS

Your input on the Proposed Plan for ihe Reeves Southeastern Galvanizing Corp. Superfund Site Operable Unit 2 is important in helping the EPA select a remedy for the site. You may use ihe space below to write your comments, then fold and mail. A response to your comment will be included in the Responsiveness Summary.

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REEVES SOUTHEASTERN GALVANIZING CORP. SUPERFUND SITE OPERABLE UNIT 2

PUBLIC COMMENT SHEET

Name Address_ City State _Zip_

Scott Martin, Remedial Project Manager U. S. EPA, Region 4 Superfund Remedial Branch Superfund Division 61 Forsyth St., SW Atlanta, GA 30303

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