National Remedy Review Board Consideration

Tremont City Barrel Fill Site

Clark County, Ohio

January 2011

1

A. Summary

1. Site Summary

Site name and location: Tremont City Barrel Fill SiteClark County, Ohio

Site account number: 2011 TR2B 05F 302DD2C B5B1BD00

Orientation to the key features of the Site and surrounding area:

The Tremont City Barrel Fill Site is located about a mile and a half west of Tremont City in Clark County, Ohio (Figure 1). Tremont City is about three miles north of Springfield, Ohio.

On-site and surrounding land use:

The Tremont City Landfill Site is just south of the Barrel Fill. The Tremont City Waste Transfer Facility Site is east of and contiguous to the Barrel Fill. See the figure on the cover sheet. The Tremont City Landfill Site and the Tremont City Waste Transfer Facility Site are not considered part of the Tremont City Barrel Fill Site. The Sites are located in a rural area; with the surrounding lands being mostly agricultural with some excavation of small borrow pits for sand and gravel. There is little residential or commercial development in the area. Tremont City has a population of about 350 people.

There is currently no activity occurring at the Tremont City Barrel Fill Site or the Waste Transfer Facility. The Tremont City Landfill Site is under State of Ohio post-closure care, with the Site owner’s contractors performing leachate collection and hauling, gas extraction and burning via flaring, and waste cap improvements. A portion of the gas extracted is piped to a nearby International Truck and Engine Corporation Plant.

Brief Site contamination history and facility operational history:

In 1976, Ohio EPA granted a permit for the specific purpose of disposal of liquid waste (containerized and uncontainerized) in the 8.5-acre Barrel Fill. This facility, operated by Danis subsidiary Industrial Waste Disposal Inc. (IWD), began accepting waste material in late-1976 and operated until late 1979, when Barrel Fill disposal operations ceased. Wastes disposed in the Barrel Fill were placed into 50 waste cells excavated into natural glacial till material. See Figure 2 for the location of the waste cells in relation to the Site. These cells were approximately 15 to 20 feet in depth. Drums were placed in layers in each of the cells. Pallets were also placed into some of the cells. After the drums were placed, uncontainerized liquid wastes were added to some of the cells prior to backfilling. Approximately 51,500 drums along with up to 304,000 gallons of uncontainerized liquids/sludges and biodegradable wastes were disposed in the Barrel Fill. Based on information in the RI Report, about 58 percent of the drummed waste is liquid and 42 percent is solid. Containerized and uncontainerized wastes include glues, resins, paint sludge, paint scrap/waste, soap/shampoo/detergent waste, asbestos slurry, caustic waste, oils, polyol, and other compounds.

2

The bulk liquids disposed in waste cells were reported in cell reports to consist of still bottoms, latex glue, soap, asbestos, asbestos water, and paint sludge. Employees recall placing polyol and paint sludges in bulk in several of the early disposal cells and placing waste sludges derived from the Waste Transfer Facility oil-water separation process into waste cells.

In addition to the drum disposal operations, land application and shallow injection of liquid biodegradable wastes from food industry sources were undertaken in the area north of the Tremont City Landfill and adjacent to the Barrel Fill between 1979 and 1980. Review of available photographs and maps indicates that this disposal likely occurred in the area to the south and west of the Barrel Fill. The disposal included the shallow injection of biodegradable waste (margarine, corn syrup, coca-cola syrup and other similar compounds) into surface soils at depths of less than one foot.

In 1980, after all Barrel Fill disposal operations ceased, a soil cover was placed over the Barrel Fill. Subsequent subsidence was repaired by filling with soil and placement of geotextile fabric to further stabilize areas where depressions and subsidence damage had occurred. Additional clean fill from a local source was placed on the Barrel Fill. Operational records indicated an initial cover thickness of three to four feet was placed on the Barrel Fill. Additional cover was added over the years, resulting in a total soil-cover thickness of 10 to greater than 17 feet over the waste cells.

In 1988, the Site owner investigated a subsurface anomaly identified by a geophysical investigation of the Barrel Fill. The Site Owner excavated an approximate 10 by 12 foot trench into the west side of the Barrel Fill to investigate the anomaly. Yellow leachate was present in the trench, and this material was sampled, pumped and disposed of. The results of the analysis of the waste indicated the material was impacted by chromium.

Between 1979 and 2002, the Site owner conducted episodic monitoring of the Barrel Fill including sampling of groundwater monitoring wells in and near the Barrel Fill.

Identify media and primary contaminants of concern (COCs) addressed by this recommended action:

There is no current human health or ecological risk associated with this Site. There is currently no significant risk of Site contaminants to the surface soil, surface water, or groundwater. Unacceptable risk is associated with threatened release of Barrel Fill contamination to a nearby surface water body and threatened release of Barrel Fill contamination to the underlying deep sand and gravel aquifer approximately 100 feet below the bottom of the Barrel Fill. Much low permeability till and three low-producing intertills lie between the bottom of the Barrel Fill and the deep sand and gravel aquifer. COCs associated with these potential exposure pathways include contaminants in the Barrel Fill which include many VOCs, SVOCs, and metals.

List the operable units addressed by this action and the media addressed by each:

The recommended action addresses all Site contamination. The objective of the recommended action is to contain the Barrel Fill contaminants and to prevent future release of contaminants to the surface water and groundwater. The recommended

3

action will extract all liquid and treat it off-site, and consolidate all solid hazardous and non-hazardous waste in an engineered waste cell on-site. The recommended action will reduce vertical and horizontal migration of Site contaminants via the groundwater-to-surface water discharge exposure route and reduce vertical migration of Site contaminants to the deep sand and gravel aquifer, which is a potable source.

2. Risk Summary

There is currently no human health or ecological risk associated with this Site. There are currently no significant releases of Site contaminants to the surface soil, groundwater, or surface water. The Site recommended action prevents a threatened release of Barrel Fill contaminants through approximately 100 feet of underlying till and three intertills to a deep sand and gravel aquifer, and prevents a release of Barrel Fill contaminants to future receptors exposed to the nearby tributary. The deep sand and gravel aquifer is currently used as a potable water source approximately one mile downgradient of the Site and less than a half mile upgradient of the Site.

3. Remediation/Cleanup Goals

The Site remediation goal is to prevent future releases of Barrel Fill contaminants to the nearby surface water and underlying groundwater. Shallow groundwater (Water Table and 1075 Intertill) has been impacted with Barrel Fill-derived contaminants above screening levels. Wells downgradient, off the Barrel Fill property in the Water Table and 1075 Intertill, do not show exceedances related to the Barrel Fill. The origin of groundwater contamination in geologic units beneath the 1075 Intertill found above screening levels could not be determined.

Table 1 shows cleanup standards that would be used for Alternative 9a, Region 5’s recommended remedial alternative, to monitor surface water and the 1075 Intertill (“Groundwater” column); and the 1050 Intertill, 1015 Intertill, and the deep sand and gravel aquifer (“Potable Use” column).

The soil cleanup goals are the thresholds for which solid hazardous and non-hazardous waste above these concentrations will be identified for containment in an engineered waste cell. The soil cleanup goals were developed to be protective of soil contaminants leaching to groundwater. Soil below these cleanup goals does not need to be managed in the engineered waste cell.

The surface water cleanup goals apply to the maintenance worker, trespasser, and ecological receptors and are based on the groundwater-discharge-to-surface water pathway. The lowest of the ecological and human health preliminary cleanup goals (PCGs) developed in the FS were used as surface water cleanup goals. The groundwater cleanup goals for the 1075 Intertill are equal to the surface water cleanup goals, based on the 1075 Intertill discharging the majority of its groundwater to the unnamed tributary.

The potable use groundwater cleanup goals apply to potable use of the 1050 Intertill, the 1015 Intertill, and the deep sand and gravel aquifer. Region 5 used MCLs as potable use cleanup goals. For COCs not having MCLs, Region 5 used Regional Screening Levels (RSLs) or Region 9 PRGs where RSLs did not exist.

4

4. Description of Alternatives

Region 5 evaluated the alternatives shown in Table 2 for cleanup of the Barrel Fill. The first 11 alternatives are from the Feasibility Study (FS) or the FS Addendum prepared by the PRPs. The 12th alternative (Alternative 9a) is from an FS Addendum (“FSA 2”) prepared by the U.S. EPA contractor CH2M Hill for Region 5. Alternative 9a was first described and evaluated by Chemical Waste Management (CWM) in a letter to Region 5 dated October 11, 2010. Alternative 9a is the result of a Region 5 request to CWM for additional information after Region 5 reviewed CWM’s Alternative 9. A description of Alternative 9 is included in a letter submitted on August 11, 2010 by CWM during the public comment period which ran from June 10, 2010 through August 11, 2010.

In August 2009, Region 5 presented Alternative 7 as its recommended cleanup alternative to the National Remedy Review Board (NRRB). Due, in part, to the NRRB’s recommendations, Region 5 identified Alternative 4a as its preferred alternative in the June 2010 Proposed Plan. As indicated below, Region 5 is now recommending Alternative 9a as its recommended cleanup alternative. As indicated above, Region 5 developed this recommendation from information received from CWM during and after the public comment period.

5. Recommended Alternative

The Region recommends Alternative 9a: Extraction, Disposal, and Treatment of All Liquid Waste; and Consolidation of All Solid Hazardous and Non-hazardous Waste in an Engineered Waste Cell. The estimated cost would be $27,746,000. Major activities include:

Excavate all waste; decant all liquids from drums; dispose of and treat all liquids off-site.

Consolidate all solid hazardous and non-hazardous waste in an engineered waste cell that includes a RCRA-compliant waste cap.

Build a slurry wall around the consolidated waste to isolate the waste and groundwater within the area of contamination.

Install leachate collection and leakage collection systems to collect liquid that migrates from the area of contamination.

Perform groundwater monitoring. Implement institutional controls.

6. Stakeholder Views

Ohio EPA:

Ohio EPA’s input to the NRRB is described in Attachment 1. It includes the following major points:

5

Alternative 4a is consistent with the intent of CERCLA and the NCP because it removes and treats all principal threat waste; contains low-level threat waste; meets CERCLA’s statutory preference for permanent solutions that employ treatment to the maximum extent practicable; and meets the NCP’s program goal of maintaining protection over time and minimizing untreated waste.

Alternative 9a is inconsistent with the intent of CERCLA and the NCP. It redefines principal threat waste to consist of only “readily pumpable” liquids. Only a small percentage of the principal threat waste is removed and treated under Alternative 9a. Unlike Alternative 4a, Alternative 9a relies on engineering controls and natural Site conditions to contain the vast majority of the Site’s untreated principal threat waste in perpetuity.

Alternative 9a does not meet CERCLA’s statutory preference to “utilize permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable.” It does not meet the NCP’s program goal of maintaining protection over time and minimizing untreated waste. It does not meet the NCP’s expectation that treatment be used to address principal threats at a site “wherever practicable” while reserving containment for waste that “poses a relatively low long-term threat or where treatment is impracticable.”

To address principal threats at the Site, CERCLA’s statutory preferences and the NCP’s program goal and expectations clearly steer U.S. EPA toward confirming selection of Alternative 4a as the final remedy while discouraging selection of Alternative 9a.

U.S. EPA should re-affirm Alternative 4a as the selected remedy for the Site.

The Community Advisory Group (CAG):

The CAG at this Site is called the Citizens for Wise Approaches Toward Environmental Resources (“CF/WATER”). See Attachment 2 for CF/WATER’s view on the upcoming remediation at the Barrel Fill. The attachment is summarized in the paragraph below.

CF/WATER concerns about Alternative 9a consist of the following major points:

Alternative 9a does not meet the nine evaluation criteria of the NCP, especially overall protection of human health and the environment; therefore, Alternative 9 is not a viable alternative.

Alternative 4a best meets the nine evaluation criteria. There needs to be a public meeting (and public comment period) for U.S. EPA

to inform the public of the dangers of leaving principal (threat) waste in the ground above one of the largest active aquifers in the United States.

Clark County Combined Health Department (CCCHD):

The CCCHD is the local public health agency near the Barrel Fill. Attachment 3 is the CCCHD input to the NRRB that includes CCCHD’s concerns of implementing any remedy that does not remove the drums. The CCCHD input includes the following major points:

6

The CCCHD is amazed that alternatives such as Alternative 9a that leave hazardous waste in place are still being considered.

Since Alternative 9a includes handling the intact drums, it makes sense to remove these drums, some of which contain hazardous waste, from the Site.

The CCCHD is against creating a new, unlined, solid waste cell at the Site. (Region 5 notes that Alternative 9a includes a bottom clay liner as well as a bottom flexible membrane liner (FML) as part of the engineered waste cell.)

In reviewing alternatives, the NRRB should consider that all applicable laws, including RCRA hazardous waste requirements, are being followed; that principal threat wastes require a permanent solution; and that excavated drums should not be placed back in the Site, given that more permanent, off-site solutions are readily available.

The aquifer beneath the Barrel Fill is of incalculable value in providing precious water resources to the community.

The PRP Group:

The RI/FS Performing Respondents for the 2002 Administrative Order by Consent (AOC) are collectively known as the Responsible Environmental Solutions Alliance (“RESA”). The Performing Respondents are comprised of the following eight companies: Delphi Corporation; General Motors Corporation; Franklin International, Inc.; International Paper Company; Procter & Gamble Company; PPG Industries, Inc.; Strebor/Roberts; and Worthington Cylinder Corporation. In 2010, Chemical Waste Management (CWM) became the ninth member of RESA; although, at that time, all requirements of the 2002 AOC had been satisfactorily completed.

RESA’s input to the NRRB is described in Attachments 4 and 5. It includes the following major points:

Alternative 9a is an appropriate remedy at a site with such low hydraulic conductivity.

Alternative 9a has redundancies built in to yield a very protective remedial option. Alternative 9a is a more favorable alternative than Alternative 4a when evaluating

the two alternatives against the first 7 of 9 evaluation criteria in the NCP. Alternative 9a is approximately half the cost of Alternative 4a.

B. Detailed Information

1. Site Name, Location, and Brief Description

The Tremont City Barrel Fill Site is located about a mile and a half west of Tremont City in Clark County, Ohio (Figure 1). Tremont City is about three miles north of Springfield, Ohio.

The Tremont City Landfill Site is south of the Barrel Fill. The Tremont City Waste Transfer Facility Site is east of and contiguous to the Barrel Fill. See the figure on the cover sheet. The Tremont City Landfill Site and the Tremont City Waste Transfer Facility Site are not considered part of the Tremont City Barrel Fill Site. The Sites are located in a rural area; with the surrounding lands being mostly agricultural with some

7

excavation of small borrow pits for sand and gravel. There is little residential or commercial development in the area. Tremont City has a population of about 350 people.

There is currently no activity occurring at the Tremont City Barrel Fill Site or the Waste Transfer Facility. The Tremont City Landfill Site is under State of Ohio post-closure care, with the Site owner’s contractors performing leachate collection and hauling, gas extraction and burning via flaring, and waste cap improvements. A portion of the gas extracted is piped to a nearby International Truck and Engine Corporation Plant.

2. Site History and Enforcement Activities

Site History

In 1976, Ohio EPA granted a permit for the specific purpose of disposal of liquid waste (containerized and uncontainerized) in the 8.5-acre Barrel Fill. This facility, operated by Danis subsidiary IWD, began accepting waste material in late-1976 and operated until late 1979, when Barrel Fill disposal operations ceased. Wastes disposed in the Barrel Fill were placed into 50 waste cells excavated into natural glacial till material. These cells were approximately 15 to 20 feet in depth. Drums were placed in layers in each of the cells. Pallets were also placed into some of the cells. After the drums were placed, uncontainerized liquid wastes were added to some of the cells prior to backfilling. Approximately 51,500 drums along with up to 304,000 gallons of uncontainerized liquids/sludges and biodegradable wastes were disposed in the Barrel Fill. Wastes included glues, resins, paint sludge, paint scrap/waste, soap/shampoo/detergent waste, asbestos slurry, caustic waste, oils, polyol, and other compounds.

The bulk liquids disposed in waste cells were reported in cell reports to consist of still bottoms, latex glue, soap, asbestos, asbestos water, and paint sludge. Statements by employees who worked at the Barrel Fill confirmed the practice of placing uncontainerized bulk materials into the Barrel Fill. Specifically, these employees recall placing polyol and paint sludges in bulk in several of the early disposal cells and placing waste sludges derived from the Waste Transfer Facility oil-water separation process into waste cells. These employees indicated that the paint sludges may have contained solvents and that recovered oils from the Waste Transfer Facility may have contained solvents and, possibly, polychlorinated biphenyls (PCBs).

In addition to the drum disposal operations, land application and shallow injection of liquid biodegradable wastes from food industry sources were undertaken in the area north of the Tremont City Landfill and adjacent to the Barrel Fill between 1979 and 1980. Review of available photographs and maps indicates that this disposal likely occurred in the area to the south and west of the Barrel Fill. The disposal included the shallow injection of biodegradable waste (margarine, corn syrup, coca-cola syrup and other similar compounds) into surface soils at depths of less than one foot.

In 1980, after all Barrel Fill disposal operations ceased, a soil cover was placed over the Barrel Fill. Subsequent subsidence was repaired by filling with soil and placement of geotextile fabric to further stabilize areas where depressions and subsidence damage had occurred. Additional clean fill from a local source was placed on the Barrel Fill. Operational records indicated an initial cover thickness of three to four feet was placed

8

on the Barrel Fill. Additional cover was added over the years, resulting in a total soil-cover thickness of 10 feet to greater than 17 feet over the waste cells.

Records indicate that a clay wall was constructed in 1985 between the Barrel Fill and the unnamed tributary to the east to mitigate seepage of groundwater to surface water. The wall was constructed of compacted clay to a depth of approximately 10 feet below ground surface and was 10 to 15 feet wide. It does not appear that the clay wall was tied into any geologic unit that would preclude contaminants from moving beneath or around the wall, and hydrogeologic data indicate that the wall has little to no effect on groundwater flow.

In 1988, the Site owner investigated a subsurface anomaly identified by a geophysical investigation of the Barrel Fill. The Site Owner excavated an approximate 10 by 12 foot trench into the west side of the Barrel Fill to investigate the anomaly. Yellow leachate was present in the trench, and this material was sampled, pumped and disposed of. The results of the analysis of the waste indicated the material was impacted by chromium.

Between 1979 and 2002, the Site owner conducted episodic monitoring of the Barrel Fill including sampling of groundwater monitoring wells in and near the Barrel Fill.

In 1999, Region 5 contracted TN & Associates (TN&A) to perform a site investigation of what is now the three-site area: the Barrel Fill, the Landfill, and the Waste Transfer Facility. The field investigation was divided into three phases. Soils, surface water, sediments, and groundwater were sampled. Phase I sampling occurred in June and August of 2000. Phase II sampling occurred between October 2000 and January 2001. Phase III sampling occurred between May and June of 2001. In March 2002, TN&A issued the Site Investigation Summary that showed, similar to the RI Report, high contaminant levels in the waste in the Barrel Fill and in the Water Table in which the Barrel Fill waste is partially submerged.

The Barrel Fill is surrounded by a security fence (chain link with three-strand barbed wire) with a locked gate entrance. The installation date of the fence is not known. The condition of the fence is currently inspected on a monthly basis and to date has not required maintenance.

Enforcement Activities

On October 3, 2002, the Performing Respondents entered into an AOC with U.S. EPA to perform the RI/FS at the Barrel Fill Site under the Superfund Alternative Approach. The Performing Respondents were collectively known as the Responsible Environmental Solutions Alliance (“RESA”). In 2010, another PRP, Chemical Waste Management (CWM), joined RESA, after completion of the final FS and FS Addendum.

RESA performed the RI field work from September 2003 through May 2005. In November 2006, Region 5 approved RESA’s RI Report for the Site. In September 2007, Region 5 approved with modifications RESA’s Alternatives Array Document. In November 2008, Region 5 approved with modifications RESA’s FS. Region 5 then approved with modifications RESA’s FS Addendum in February 2010. The FS Addendum contains information on Alternatives 4a, 4b, 5a, 5b, and 7.

9

In June 2010, Region 5 issued the Proposed Plan to the public. The Proposed Plan identified Alternative 4a as Region 5’s preferred alternative. The extended public comment period ran from June 10, 2010 through August 11, 2010. On the last day of the extended public comment period, CWM submitted information on two additional remedial alternatives. Region 5 reviewed this information and, in response to questions on it, CWM prepared another alternative, Alternative 9a, as documented in CWM’s October 11, 2010 letter.

In November 2010, Region 5 tasked its contractor, CH2M Hill, to produce an FS Addendum that described and evaluated Alternative 9a. In December 2010, Region 5 worked with CH2M Hill to complete a draft-final version of this FS Addendum, called FS Addendum 2 (“FSA 2”).

3. Scope and Role of Operable Unit or Response Action

Alternative 9a, Region 5’s recommended remedial alternative, addresses all Barrel Fill Site contamination. Under Region 5’s recommended remedial action, all principal threat liquid waste would be removed from the Barrel Fill. Solid hazardous and non-hazardous waste would be managed in an engineered waste cell with leachate and leakage collection, and with a slurry wall surrounding the waste.

4. Site Characteristics

The Barrel Fill is located in the Great Miami River Basin, which is included in the Till Plains Region of the Central Lowland physiographic province. The Barrel Fill lies in the boundary of the Southern Ohio Loamy Till Plain and the Mad River Interlobate Plain.

The area topography is flat to gently rolling with variations in topography attributed to river valleys and glacial features. The highest elevation at the Barrel Fill is approximately 1,120 feet AMSL (near the northwest corner). The Barrel Fill slopes gently eastward toward the unnamed tributary that eventually discharges to Chapman Creek. This tributary originates near the Barrel Fill and flows into a former borrow pit area located to the east of the Barrel Fill, before flowing into Chapman Creek. This borrow pit has an elevation of approximately 100 feet below the elevation of the Barrel Fill.

The area is characterized by glacial silt, clay, sand, and gravel deposits of variable thickness, underlain by the regional carbonate aquifer. The carbonate bedrock aquifer is composed of limestone and dolomite formations of Silurian age. Groundwater occurrence and movement within the bedrock aquifer is most likely associated with bedding planes, fractures, solution channels and the degree of interconnections between them. The bedrock aquifer is used as a domestic water supply in the area, and wells installed in this aquifer typically yield 10 to 20 gallons per minute (gpm) and, in some instances, produce yields of approximately 100 gpm.

The bedrock surface is overlain with a thick mantle of glacial drift, comprised of cohesive clay and silty glacial till with occurrences of somewhat stratified layers of sand and gravel glacial outwash deposits. In local areas, the sand and gravel glacial outwash deposits may produce as much as 100 gpm. In addition, later valley train deposits were deposited in the stream valleys near the Site including Chapman Creek

10

and the Mad River Valley. These deposits make up the Mad River Buried Valley Aquifer (MRBVA, also known as the deep sand and gravel aquifer in this report) and consist of massive sand and gravel deposits with yields of up to 1,000 gpm. The City of Springfield, which is located approximately 3.5 miles southeast of the Barrel Fill, uses the MRBVA for production of potable water. The Springfield municipal water system serves approximately 74,000 residents with water produced from this aquifer.

The hydrogeology beneath the Barrel Fill is characterized by a series of tills and intertills as shown in Figure 3. The figure shows that the waste cells are partially submerged in the Water Table and that the flow from the upper water zones is to the unnamed tributary to the east. Groundwater flow in the deep sand and gravel aquifer, which is about 100 feet below the bottom of the waste cells, is generally to the north and northeast.

Vertical groundwater flow from the Barrel Fill to the deep sand and gravel aquifer is very slow, equating to a time of travel of vertical groundwater contamination of about 1,000 years or more. However, since most of the groundwater in the upper water zones flows to the east via the intertills, little groundwater flows vertically. Implementation of Alternative 9a would significantly reduce an already minimal flow of vertical and horizontal contaminant migration.

The Barrel Fill is completely fenced and bordered by the Waste Transfer Facility Site to the south and east. The Tremont City Landfill Site is to the south of the Barrel Fill, with Snyder-Domer Road and Chapman Creek located approximately 3,000 feet south of the Barrel Fill. Clarkco, a subsidiary of the Danis Corporation, owns property to the north, west, and east of the Barrel Fill. An intermittent stream (“the unnamed tributary”) lies east of the Barrel Fill, and this stream empties into Chapman Creek.

Nature and Extent of Contamination

There are high levels of metals, volatile organic contaminants (VOCs), semi-volatile organic contaminants (SVOCs), and pesticides in the barrels and uncontainerized waste in the Barrel Fill. The 10-17 feet thick soil cover above the Barrel Fill showed little contamination. No compounds detected in soil vapor exceeded screening criteria. Surface water and sediment in the unnamed tributary showed little contamination. Intertills beneath the Water Table and the Water Table outside of the waste management unit showed little contamination, and there is no strong evidence of low levels of contamination in the deep sand and gravel aquifer being attributable to the Barrel Fill.

Soil

No soil sampling results associated with the soil cover were above screening levels with the exception of one arsenic sample (31.1 mg/kg). Remaining sampling results of arsenic in soil were consistent with background levels found in southwest Ohio.

Soil Vapor

11

A soil vapor survey included the collection and field analysis (using a flame ionization detector (FID)) for total organic vapors from 10 background and 50 investigative samples. Background samples were collected from an area situated several hundred feet north of the Barrel Fill. Investigative samples were collected from 50 sampling locations directly over the waste cells. Evaluation of the field analyses indicated that 32 of the 50 investigative samples exceeded background soil vapor concentrations, but not health-based screening criteria. Samples from 18 of these locations and two background locations were analyzed for VOCs. Results of these analyses indicate that 28 VOCs were detected in at least one of the soil vapor samples analyzed.

Numerous VOCs detected in soil vapor were also detected in drum samples, test pit water, test pit saturated soils and unsaturated soils. These results indicate a correlation between VOCs in these media that may result from transport of VOCs from the wastes to soil vapor. Evaluation of the soil vapor results indicated that no soil vapor-to-ambient air screening criteria were exceeded.

Waste

Sampling results from the waste cells in the Barrel Fill from buried drums, and uncontainerized solid and liquid waste showed high levels of metals, VOCs, SVOCs, and pesticides. In many cases, these levels were far above screening levels. The drums contain solid and liquid waste, with about half the waste being categorized as RCRA hazardous waste.

Groundwater

The groundwater quality data obtained during the RI indicate several VOCs and manganese from the Barrel Fill have impacted shallow (Water Table) groundwater above screening levels. Groundwater monitoring well HMW-301 had the highest contaminant concentrations in the Water Table. This well is immediately adjacent to the Barrel Fill, approximately 15 to 20 feet east and hydraulically downgradient of waste cells E7 and D9 on the southeast corner of the Site. See Figure 4.

Exceedances in HMW-301 compared to the screening criteria, in ug/l, include manganese (1,710 compared to 730); 1,1,1-TCA (7,000 compared to 200); 1,1-DCA (1,900J compared to 5); acetone (1,100J compared to 610); chloroethane (1,000 compared to 4.6); cis-1,2-DCE (150J compared to 70); methylene chloride (92J compared to 5); TCE (6.1 compared to 5.0); and vinyl chloride (8.2 compared to 2.0).

Wells HMW-703, HMW-704 and HMW-702 are located hydraulically downgradient of HMW-301 and do not contain contaminants detected in HMW-301 above screening levels. Water Table wells other than HMW-301 that are located immediately adjacent to the waste disposal cells that showed contamination above screening levels include wells HBF-15S, HBF-5B, HBF-5, HBF-10S, HMW-701, HMW-702, and HMW-703. Exceedances include metals (arsenic, iron, lead, and manganese), pesticides (dieldren, alpha-BHC, and beta-BHC), VOCs (1,1,2,2-TCA and dibromochlormethane) and SVOCs (bis (2-ethylhexyl) phthalate). See Figure 4.

The RI showed a number of screening level exceedances in the 1075 Intertill; mostly of metals. In addition, one exceedance of TCE was reported, along with two estimated exceedances of pesticides (dieldren and alpha-chlordane). Figure 5 shows the

12

locations of the 1075 Intertill wells that had exceedances, along with each exceedance. The greatest exceedances in these wells compared to the screening criteria, in ug/l, include arsenic in BF-23D (21.5 compared to 10.0); antimony in HBF-19S (10.7 compared to 6.0); iron in HMW-305 (46,700 compared to 11,000); lead in HMW-305 (26.1 compared to 15.0); manganese in BF-228 (7,760 compared to 730); alpha-chlordane in HMW-204 (0.17J compared to 0.17); dieldrin in HBF-15D (0.028J compared to 0.0042), and TCE in HBF-15D (13 compared to 5).

For background metals concentrations in groundwater, the RI Report documented that the arsenic concentrations from groundwater samples collected were consistent with naturally occurring groundwater concentrations in southwestern Ohio. The RI Report also documented that manganese and iron concentrations have exceedances in wells upgradient of the Barrel Fill; therefore, these contaminants are not considered Site-related. Finally, the RI Report documented that, based on the lead concentrations relative to sample turbidity, it is likely that lead exceedances are related to suspended solids and not groundwater conditions.

Contaminant level exceedances in the groundwater zones beneath the 1075 Intertill (the 1050 Intertill, the 1015 Intertill, and the deep sand and gravel aquifer) could not be attributed to Barrel Fill contamination.

To determine whether an exceedance was related to Barrel Fill contamination, Region 5 considered topics such as:

reproducibility of sampling results (consistency of the sampling result with other rounds of sampling);

naturally occurring conditions (e.g., high levels of arsenic are prevalent in groundwater in southwestern Ohio);

concentration gradients (how a sampling result in one groundwater zone compared to sampling results in groundwater zones above or beneath it); and

comparison to upgradient sampling results (in general, a downgradient sampling result should have a higher contaminant concentration if it is related to Barrel Fill contamination).

In summary, shallow, on-site groundwater (Water Table and 1075 Intertill) has been impacted with Barrel Fill-derived contaminants above screening levels. Wells downgradient, off the Barrel Fill property in the Water Table and 1075 Intertill, do not show exceedances related to the Barrel Fill. The origin of groundwater contamination in geologic units beneath the 1075 Intertill found above screening levels could not be determined, but is not believed to be related to Barrel Fill contamination.

Surface Water and Sediment

Results of surface water and sediment sampling indicated that potential Barrel Fill-related contaminants were detected in samples collected from the unnamed tributary. Eight VOCs were detected in the surface water sample and 15 VOCs were detected in sediment samples. Evaluation of surface water sampling results indicates concentrations of these compounds were below applicable surface water criteria. Evaluation of sediment sampling results indicates that 1,1-dichloroethane, acetone, barium, and manganese exceeded ecological screening criteria. This contamination

13

may have migrated from Barrel Fill waste into Water Table groundwater and into surface water, but does not require remedial action.

Contaminant Transport

As shown in Figure 3, the waste cells are partially submerged in the Water Table. Most of the groundwater from the Water Table flows laterally to the unnamed tributary, with the remainder flowing vertically downward. Despite this circumstance, no appreciable contamination has been found in the unnamed tributary, indicating a slow, lateral migration of contaminants from the Barrel Fill as well as reducing processes in place.

Results of groundwater sampling in well HMW-301 (in the southeast portion of the Barrel Fill and east of the waste cells) indicated that hazardous substances have migrated beyond the extent of the waste cells into the Water Table. Groundwater samples contained concentrations of 1,1,1-trichloroethane (7,000 ug/l compared to an MCL of 200 ug/l), 1,2-dichloroethane (19 ug/l compared to an MCL of 5 ug/l), cis-1,2-dichloroethene (150J ug/l compared to an MCL of 70 ug/l), vinyl chloride (8.2 ug/l compared to an MCL of 2.0 ug/l), and a number of other constituents that exceeded screening levels. Maximum concentrations were, in general, significantly lower (an order of magnitude or more in most cases) than maximum concentrations detected in the waste-cell water. For example, the maximum concentration of 1,1,1-trichloroethane in waste-cell water was 26,000 ug/l, compared to 7,000 ug/l detected in the downgradient samples.

Maximum concentrations of constituents detected in Water Table groundwater samples collected from wells located more than 90 feet downgradient of the waste cells were much lower than those detected in either waste-cell water or the nearby downgradient well noted above, and were below risk-based screening levels based on potable use. Generally, these concentrations were in the part-per-billion range, several orders of magnitude less than concentrations in waste-cell water.

Several of these VOCs were detected in surface water and sediment samples collected from the unnamed tributary, downgradient of the wells noted above. Typically, these compounds were present at concentrations of less than one part per billion (four to five orders of magnitude less than the maximum concentrations detected in waste-cell water). Based on this analysis, it appears that the Water Table groundwater with Barrel Fill-related constituents has migrated and is migrating from waste cells to the unnamed tributary.

A small portion of the Water Table groundwater flow is downward into the 1075 Intertill (see Figure 6). The RI Report calculated the vertical groundwater flux between these units to be approximately one to two orders of magnitude less than the horizontal flux calculated. This indicates the preferred pathway for impacted groundwater will be horizontal through the more permeable Water Table.

The till between the bottom of the Barrel Fill and the deep sand and gravel aquifer measures approximately 100 feet. The hydraulic conductivity beneath the Barrel Fill is very low; approximately 10-7 cm/sec or less. Therefore, it is reasonable to assume that a release from the Barrel Fill to the deep sand and gravel aquifer will be very slow and

14

will take about 1,000 years. Furthermore, there are three intertills between the bottom of the Barrel Fill and the deep sand and gravel aquifer that will serve as warning monitoring points.

Waste material consists of containerized and uncontainerized wastes disposed directly into 50 waste cells at the Barrel Fill. In general, these wastes are present at depths beneath the Water Table. Results of the RI indicated that VOC hazardous substances are present within waste-cell water, in the Water Table downgradient of the Barrel Fill, and in soil vapor directly above waste cells in the Water Table.

The timing of past releases at the Barrel Fill is not currently known; however, RI results and operational records indicate that uncontainerized bulk waste has been present in numerous cells since the Barrel Fill was first operational in 1976. As such, uncontainerized material capable of migrating from the Barrel Fill has been present since the start of drum disposal. Observations on drum conditions during the RI test pit investigation indicate that at least some drums were compromised (although, the majority of the drums were still in good condition). It is expected that the compromised drums have also contributed to past and ongoing releases from the Barrel Fill. The direct observation of LNAPL in two waste cells, each of which has no documented placement of uncontainerized waste within the cells, is evidence of such drum deterioration or undocumented, uncontainerized waste disposal. It is expected that these drums will continue to deteriorate over time and will serve as additional sources of groundwater contamination if no action is taken.

5. Current and Potential Future Land and Water Uses

Land Uses

The 8.5-acre Tremont City Barrel Fill Site has been closed as a barrel fill operation since 1980. Since the Site closed, the land on the Site has not been used. The Site is primarily surrounded by undeveloped land, including land used for agricultural purposes. According to German Township records, the Site is currently zoned as M-2 (heavy-duty industrial). The land use and designation is expected to remain unchanged.

Groundwater and Surface Water Uses

There is currently no groundwater use at the Site, and no water supply wells exist on-site. Furthermore, State of Ohio regulations prohibit installation or use of drinking water wells on a closed landfill, such as the Site. The only on-site surface water body is the ephemeral, unnamed tributary located adjacent to and east of the Barrel Fill.

Groundwater is the primary source of potable water in the vicinity of the Site. Eighty-six potable water wells have been identified within one mile of the Site. Currently, the deep sand and gravel aquifer is used as a potable water source by nearby residents. Region 5 and Ohio EPA also consider the 1050 and 1015 Intertills to be potable water sources; although, neither of these sources is currently being used for potable water.

Groundwater use is expected to continue in the same manner.

15

6. Summary of Risk

Human Health Risk

The HHRA considered two general receptor populations to be present at the Site as currently used: maintenance worker and trespasser. Based on the related risk estimates, potential impacts to ambient air, surface soil, and current surface water conditions do not pose unacceptable risk. However, the risk estimates indicate unacceptable risk levels from potential exposure to future groundwater-to-surface water discharge.

Although not quantified, potential direct contact with the complex and concentrated mixture of materials in the waste cells during excavations will represent an unacceptable risk to future maintenance workers without appropriate engineered controls, administrative controls, and personal protective equipment.

The HHRA did not identify any risk from potable use of the deep sand and gravel aquifer. However, due to post-RI Report evaluations of the geology beneath the Barrel Fill, Region 5 has determined that potable use of the deep sand and gravel aquifer is a valid exposure pathway and that future risk associated with potable use of this aquifer must be considered while evaluating remedial alternatives.

Ecological Risk

Results of the Screening Level Ecological Risk Assessment (SLERA) indicate that wildlife habitat of various levels of quality is available within the Barrel Fill and surrounding areas. Ecological receptors such as terrestrial and semi-aquatic fauna are likely to inhabit and/or use these areas, and exposure pathways may exist for these receptors. Surface soil, sediment, and surface water represent potential exposure media. Although several contaminants of potential ecological concern (COPECs) have been identified for surface soil, sediment, and surface water, it is important to note that the majority of these contaminants were retained as COPECs because they lack ecological screening criteria and/or are considered to be persistent, bio-accumulative, or toxic (PBT). Furthermore, for those few contaminants that were retained as COPECs because they exceeded their associated screening criteria, it is noted that these exceedances do not necessarily indicate the occurrence of ecological risks. Contaminants identified as COPECs were detected at relatively low frequencies (limited sized area), and the magnitudes of criteria exceedances were also relatively low.

Several contaminants were identified during the screening process as COPECs for surface soils, sediment, and surface water. These contaminants are not likely to present a significant ecological risk for one or more of the following reasons:

Their low concentrations and environmental fate properties (e.g., volatilization) minimize the potential for significant ecological exposure;

There was an infrequent detection, low concentration, and/or the extent of the COPECs in soil is limited in terms of potential ecological exposure;

The concentration is typical of background concentrations in soil for the area; or The concentrations were less than soil background levels.

16

Therefore, the detected contaminants and their associated concentrations are not expected to pose an unacceptable ecological risk to receptors that may inhabit and/or use habitats at or in the vicinity of the Barrel Fill, and no further ecological assessment of potential exposures to these media was required.

The modeled concentrations of many of the groundwater-to surface water discharge COPECs described above are significantly higher than the screening criteria. As such, these contaminants and their associated concentrations are expected to pose an unacceptable future ecological risk to receptors that may use the unnamed tributary.

Based on the magnitude of these exceedances, additional evaluation and ecological risk characterization was not required to establish a probable ecological risk under the modeled conditions. The magnitude of exceedances was enough to conclude that future discharge of groundwater to surface water will result in unacceptable risk to ecological receptors exposed to the surface water.

Additional investigation or measurement of ecological or environmental affects within the unnamed tributary from this future modeled discharge was not necessary. The magnitude of COPEC exceedances compared to screening levels was such that potential significant impacts on aquatic organisms are possible in this future scenario for the seep. In addition, given the sensitive and high quality habitat described for Chapman Creek, the potential for these COPECs to discharge and flow into Chapman Creek at concentrations exceeding screening criteria is considered unacceptable for purposes of the screening assessment.

Therefore, the potential for the higher concentrations of Barrel Fill contaminants found in the Water Table Unit and in the waste cells to migrate with groundwater and discharge to surface water results in a potentially unacceptable ecological risk in the unnamed tributary. Although no additional ecological assessment is required, the SLERA concluded that unacceptable risk to the environment exists from the potential for Barrel Fill contaminants to discharge in the future to surface water.

7. Remedial Action Objectives (RAOs)

The RAOs for the Barrel Fill Site are as follows:

Prevent human exposure to groundwater COCs greater than a cumulative total excess lifetime cancer risk of 1 x 10-5 or a target organ hazard index greater than 1.0 for reasonably anticipated exposures;

Prevent discharge of contaminated groundwater to surface water in excess of

ecological criteria;

Prevent human exposures to hazardous substances in indoor air to a resident living on the Barrel Fill Site;

Prevent direct contact human exposures to hazardous substances in the wastes;

Stabilize or eliminate hazardous substances in drums, barrels, tanks, or other bulk storage containers that may pose a threat of release;

17

Prevent future contamination of groundwater;

Ensure that the remedial action is protective in the event of a catastrophic release of contamination from the drums; and

Prevent migration of Site contaminants above risk-based levels to the Site land surface, the unnamed tributary, the deep sand and gravel groundwater unit, and to future indoor air.

8. Description of Alternatives

Each of the 12 remedial alternatives includes the following elements except for the “No-Action Alternative.”

Fencing - Placing fencing and signs around the Site, except for remedial Alternatives 4 and 6, since no wastes will remain on-site;

Relocation of the unnamed tributary to facilitate remedial construction activities, except for remedial Alternatives 4, 6, and 9a;

Institutional controls - Preventing or limiting exposure to hazardous substances using environmental covenants to prohibit, for example, residential use on the Site, to be developed and instituted under common law, and the Ohio Environmental Covenants Act;

Long-term ground water monitoring - Monitoring the groundwater on a long-term basis to verify effectiveness and reliability of the remedy; and

Contingency planning - Taking action if unexpected conditions occur that may adversely affect the remedy; for example, contaminated groundwater moving off-site or contaminated substances remaining on-site affecting groundwater or surface water.

Remedial Alternative 1 – No action

The No-Action Alternative is a basis for comparison to the other cleanup alternatives. Since no action would be taken, this option would not protect human health and the environment from future risk.

Remedial Alternative 2

Alternative 2 includes the installation of a downgradient groundwater collection trench to collect contaminated groundwater. This groundwater would then be treated on-site, and the treated groundwater would be disposed of in a nearby surface water body. Alternately, the groundwater collected would be transported to a wastewater treatment plant for treatment.

Groundwater collection would be accomplished by digging a long trench along the eastern side of the Barrel Fill. (Shallow groundwater at the Site generally flows in an eastern direction.) The trench would slope toward manholes and pumping stations to promote flow. Permeable, slotted piping would be laid across the bottom of the trench to promote flow to the manholes. Additionally, extraction wells would be installed in the 1050 Intertill to allow for future groundwater collection and treatment if needed.

18

Alternative 2 also includes regrading the existing waste cover to provide drainage and promote surface water runoff.

Remedial Alternative 3

Alternative 3 includes all of the elements of Alternative 2 along with the installation of an upgradient groundwater diversion structure consisting of an excavated trench bentonite slurry wall or driven sheet pile wall. The diversion structure would be located just west of the Barrel Fill and extend along its length. The purpose of the structure would be to keep groundwater from entering the Barrel Fill, thereby reducing the amount of contaminated liquid being generated.

Remedial Alternative 4

Alternative 4 involves a full waste excavation and disposal of excavated waste off-site. Wastes would be transported off-site via bulk tankers and bulk trailers, and treated at commercial treatment, storage, and disposal facilities (TSDFs) or solid waste facilities, as appropriate. The resulting excavation would be backfilled and graded.

Removal of drums, uncontainerized waste, cell water, and soil would require extensive excavation and waste handling for a variety of solid and liquid wastes, and contaminated media.

Excavation would proceed from cell to cell. Once a cell is encountered, the cell would be dewatered by pumping from sumps constructed in the base of the cell. The cell water would be pumped to storage containers and LNAPL, if present, would be placed in a separate container. Soils, including those from the existing soil cover, would be segregated into “clean” and “dirty” stockpiles based on visual observation and field screening. Once a section of excavation is completed, confirmation sampling would be conducted to verify that contaminant concentrations are below cleanup goals. Once cleanup goals were met, the section would be backfilled for Site restoration, and another section would be excavated until all wastes were removed from the Site. Non-hazardous soils with testing results less than soil cleanup goals (based on soil leaching to groundwater) would be used as backfill during Site restoration.

Cell liquids and solids not from drums would be tested for hazardous waste characterization. Non-hazardous soils with testing results less than the soil cleanup goals would be reused as backfill during Site restoration.

Drums would be removed from the waste cells and transferred to drum staging pads. Leaking and unstable drums would be placed into overpack containers. After sampling, analysis, and characterization of drum contents, drums would be emptied into bulk containers containing compatible wastes.

A number of TSDFs would likely be used for off-site waste disposal. Non-hazardous waste disposal facilities would be used for conventional landfilling. Water treatment facilities would be used for the treatment and disposal of cell water.

Remedial Alternatives 4a and 4b

19

Alternative 4a is a variation of Alternative 4. The difference in Alternative 4a is that non-hazardous, solid, drummed wastes and non-hazardous soils would be placed in a newly constructed waste cell consistent with the requirements for a State of Ohio solid waste landfill; however, the bottom of the landfill would not include an FML. The landfill bottom would be constructed and sloped to facilitate the collection and removal of leachate. Installation of a cap system would minimize surface water infiltration. Alternative 4a also includes relocation of the tributary east of the Barrel Fill in order to promote effective installation and operation of the newly constructed waste cell.

Alternative 4b is similar to Alternative 4a except that Alternative 4b includes the installation of an FML at the bottom of the landfill that would serve as an additional barrier to prevent leachate discharge to groundwater or surface water.

Remedial Alternative 5

Alternative 5 is a variation of Alternative 4; the variation is the on-site treatment of hazardous soils and other residuals, and the construction of an engineered waste cell. After the materials are treated to levels that render them non-hazardous, they would be placed in a newly constructed waste cell consistent with the requirements for a State of Ohio solid waste landfill. Alternative 5 also includes relocation of the tributary east of the Barrel Fill in order to promote effective installation and operation of the newly constructed waste cell. The process option selected for on-site treatment would be high-temperature thermal desorption (HTTD) for organics and stabilization for metals. HTTD separates organics from soil by raising the temperature to volatilize organics and transfer them to a gas stream. HTTD would include a primary thermal separation treatment followed by a secondary treatment for the gas by-product. Stabilization is a chemical treatment that reduces mobility of inorganics using a stabilizing agent.

Following successful separation of organics by HTTD and immobilization of metals by stabilization, the soil would be placed in the former Barrel Fill in the newly constructed waste cell. Components of this solid waste landfill would include a liner system to prevent leachate discharge to ground or surface waters, leachate collection and management, and a cap system that minimizes surface water infiltration.

Remedial Alternatives 5a and 5b

Alternative 5a is a variation of Alternative 5. The difference is that for Alternative 5a, non-hazardous, drummed, solid wastes and non-hazardous soils would also be placed in the newly constructed waste cell consistent with the requirements for a State of Ohio solid waste landfill. The bottom of the landfill would be not include an FML, but would include recompacted soil.

Alternative 5b is similar to Alternative 5a except that Alternative 5b includes the installation of an FML at the bottom of the landfill that would serve as an additional barrier to prevent leachate discharge to groundwater or surface water.

Remedial Alternative 6

20

Alternative 6 includes the elements of Alternative 5 with the exception that the treated soils would be disposed of off-site at a solid waste landfill. Therefore, construction and maintenance of an on-site waste cell conforming to State of Ohio solid waste landfill requirements would not be required.

Remedial Alternative 7

Alternative 7 includes all elements of Alternative 3 with the additional installation of liquid waste removal sumps at all waste cell locations. The purpose of the sumps would be to remove cell water, uncontainerized liquid wastes, infiltration from precipitation, and liquids that could be released by the drums. The sumps would assist to reduce the build-up of hydraulic head (pressure caused by liquid build-up) in the waste cells, further reducing groundwater flow.

One sump would be installed just below each waste cell and at a location adjacent to each cell to optimize the collection of liquid. Portable pumps that are moved from sump to sump and removed between pumping events would be used to collect the liquids. The liquid wastes removed by the pumping would be stored in tanks; then, transported off-site for disposal and treatment.

Sumps would be equipped with level sensors connected to a central control panel. The control panel would alert off-site operation and maintenance (O&M) personnel that liquid levels had risen above a pre-determined level. Once alerted, O&M personnel would respond and pump the liquid from the sumps. Routine O&M activities occurring during the pumping visits would also include measuring liquid levels in each sump, and cleaning sumps and pumps.

As noted above for Alternatives 2 and 3, Alternative 7 includes the installation of extraction wells in the 1050 Intertill to allow for future groundwater collection and treatment if needed as part of contingency planning (i.e., if the 1050 Intertill becomes contaminated above potable use cleanup goals). These wells would also be part of the overall groundwater monitoring network that includes all of the water zones.

Remedial Alternative 9a (EPA’s Recommended Cleanup Alternative)

Alternative 9a involves full waste excavation, disposal and treatment of all liquid waste off-site, and consolidation of solid hazardous and non-hazardous waste in an engineered waste cell on-site. Figures 7 and 8 below show an overhead and cross-sectional view of this alternative, respectively.

The existing soil cover would be removed and staged before excavating drummed and uncontainerized waste. All uncontainerized liquid and liquid from drums would be disposed of and treated off-site at a TSDF or POTW. As defined, in part, in U.S. EPA Solid Waste and Emergency Response’s training module for containment buildings (EPA530-K-05-008), liquid wastes include “wastes that flow under their own weight to fill the container in which they are placed” or “are readily pumpable.” Decanting or pumping of the liquid wastes from the drums will be conducted to remove the “free-standing liquids” that form distinct pools or layers above or below the waste before disposal. These drums would then be compacted before being consolidated in the Barrel Fill.

21

An engineered waste cell would be constructed to hold the solid hazardous and non-hazardous waste. The engineered waste cell would include a bottom clay liner along with an FML. The solid waste would be covered by a RCRA-compliant hazardous waste cap. A leachate collection system would be installed above the bottom liner, and leachate would be pumped to on-site storage tanks for eventual off-site disposal and treatment.

A slurry wall, keyed into the till beneath the 1075 Intertill would be installed around the engineered waste cell for the purpose of physically isolating the waste and groundwater at the Site. A leakage collection system would be installed beneath the engineered waste cell as a back-up system to collect any liquid not collected by the leachate collection system. This liquid collected would be directed to the same storage tanks as used for the leachate collection system.

9. Comparative Analysis of Alternatives

A brief summary of the comparative analysis of the 12 alternatives under the nine criteria follows:

Protection of Human Health and the Environment

The 12 alternatives offer varying levels of protection of human health and the environment.

The No-Action Alternative offers no protection, since principal threat waste is left in place, and exposure pathways resulting in significant risk would remain. Excavation alternatives 4, 4a, 4b, 5, 5a, 5b, and 6 fully protect human health and the environment since they remove and treat all principal threat waste, thereby eliminating exposure pathways involving significant risk.

Containment alternatives 2 and 3 protect human health and the environment. Although some liquid waste from the Barrel Fill will be collected and treated, a non-negligible percentage of liquid waste may migrate to the deep sand and gravel aquifer and result in significant risk to nearby receptors. The timeframe for this migration is difficult to predict but estimated by Region 5 to be approximately 1,000 years. It is also difficult to predict what contaminant concentrations will exist when the contamination reaches the deep sand and gravel aquifer.

Alternative 7, which includes containment and liquid waste extraction and treatment, protects human health and the environment. The liquid extraction system will collect a portion of the liquid principal threat waste, which will then be transported off-site for treatment. The solid hazardous and non-hazardous waste would remain in place in the Barrel Fill. The downgradient collection trench will collect for treatment residual liquid waste not collected by the cell sumps. The upgradient diversion trench will prevent most of the water from entering the Barrel Fill, thereby reducing the occurrence of water mixing with waste to produce liquid waste.

Alternative 9a protects human health and the environment. Alternative 9a removes and treats all of the liquid principal threat waste but leaves the solid hazardous and non-hazardous waste at the Site in an engineered waste cell. This alternative has protective

22

measures in place to significantly reduce the occurrence of any leachate generated from the solid hazardous waste from migrating to the drinking water aquifer. These protective measures include an engineered waste cell with a clay liner and FML at the bottom of the cell, a slurry wall completely around the waste cell, a RCRA-compliant waste cap, a leachate collection system, and a leakage collection system.

Compliance with ARARs

All alternatives except for the No-Action Alternative and Alternative 5a comply with ARARs. Alternative 5a would not use an FML at the bottom of the waste cell; therefore, it would not comply with the requirements of OAC 3745-27-08 (sanitary landfill disposal facility construction. A waiver for this ARAR would be needed if Alternative 5a was selected for implementation because wastes would be removed from the area of contamination, treated in a separate unit, and redeposited in the same area of contamination.

Long-term Effectiveness and Permanence

The No-Action Alternative is not effective at reaching remedial action objectives. Excavation alternatives 4, 4a, 4b, 5, 5a, 5b, and 6 offer long-term effectiveness and permanence because there will be little or no risk remaining after all liquid waste and all hazardous waste is removed and treated.

Alternatives 2 and 3 are not long-term effective and permanent. Liquid wastes are likely to eventually reach the deep sand and gravel aquifer.

Alternative 7 is not as long-term effective and permanent as the excavation alternatives. Some of the principal threat liquid waste will be collected by the cell sumps and treated off-site. The upgradient trench will prevent much groundwater from entering the Barrel Fill, and the downgradient trench will collect residual contamination that escapes the cell sump collection system. A small percentage of contaminated liquid may still migrate to the deep sand and gravel aquifer.

Alternative 9a provides long-term effectiveness and permanence. This alternative removes and treats off-site all highly mobile, liquid principal threat waste, including that in the drums. Solid hazardous and non-hazardous waste will be consolidated in an engineered waste cell on-site and will be reliably contained. The engineered waste cell with clay and FML for the bottom liner, along with a RCRA-compliant waste cap, slurry wall, and leachate and leakage collection systems is expected to eliminate contaminated liquid from reaching the drinking water aquifer. This type of design has been implemented effectively at other sites to minimize leachate generation and migration of contaminated liquid to groundwater zones.

Reduction of Toxicity, Mobility, or Volume through Treatment

The No-Action Alternative does not include treatment; therefore, it does not reduce the toxicity, mobility, or volume of any waste through treatment. Excavation alternatives 4, 4a, 4b, 5, 5a, 5b, and 6 fully reduce the toxicity, mobility, or volume of liquid waste and all hazardous waste, because these wastes are removed and treated.

Containment alternatives 2 and 3 do not significantly reduce the toxicity, mobility, or 23

volume of waste. A percentage of groundwater flowing from the Barrel Fill would be collected and treated, but that would not result in a significant reduction of toxicity, mobility, or volume of waste.

Alternative 7 reduces a portion of the toxicity, mobility, and volume of liquid waste by extracting and treating the liquid waste collected from sumps. However, the solid hazardous and non-hazardous waste and the remaining liquid waste would not be treated.

Alternative 9a fully reduces the toxicity, mobility, or volume of all highly mobile, liquid waste through treatment. All remaining solid waste would not be treated but would be reliably contained. Alternative 9a fully addresses the treatment of highly mobile, liquid principal threat waste.

Short-term Effectiveness

There are some concerns regarding short-term effectiveness for excavation alternatives 4, 4a, 4b, 5, 5a, 5b, 6, and 9a. It would take about two years to remove and treat the hazardous waste for these alternatives. Short-term risk to workers could be significant during excavation and on-site treatment activities (on-site treatment for alternatives 5, 5a, 5b, and 6); although, health and safety measures would be in place and would be expected to provide adequate safety. Air monitoring for excavation alternatives will be in place during excavation activities, and mitigative measures will be used to minimize risk to the workers and community if air monitoring thresholds are exceeded. Risk to the community would exist from trucking hazardous waste off-site. Risk to the community would be less for Alternative 9a than for the other excavation alternatives because only liquid waste would be transported off-site. Airborne risk to the community for alternatives 5, 5a, 5b, and 6 would exist from operation of an on-site HTTD system; although, safeguards would be in place. Risk would exist from potentially contaminating the 1075 Intertill during excavation activities; although, dewatering the waste cells would minimize this risk.

The containment alternatives 2 and 3 present minimal short-term risks. All waste is left in place, and standard construction practices would provide for remedy completion. These alternatives would involve little risk to the workers and community. Any liquids collected in the downgradient collection trench requiring off-site treatment would present a minimal risk to the community as the liquids are transported off-site.

Alternative 7 presents some significant short-term risks. The installation of the sumps at the bottom and the edge of the cells will require drilling through Barrel Fill hazardous waste. Proper placement of the sumps will be difficult. Minimal risk to the community will exist from transporting the collected liquids off-site for treatment.

Implementability

The excavation alternatives would be implementable, albeit difficult. Significant coordination among numerous parties, such as local government agencies, traffic control, contractors, and disposal facilities would be required. Less coordination would be needed for excavation alternatives that leave a percentage of the waste on-site (all except alternatives 4 and 6). There is a concern about excavating the large volume of waste in an unstable setting. (Test pit walls collapsed during the RI field work.) Proper

24

excavation procedures would be followed. For excavation alternatives 4a, 4b, 5, 5a, 5b, and 9a, construction of an on-site landfill would be readily implementable. Construction and operation of an HTTD system on-site for alternatives 5, 5a, 5b, and 6 is implementable; although, few vendors may be available.

Containment alternatives 2 and 3 are implementable. Collection, treatment, and discharge of groundwater are readily implementable using proven technologies. Installing collection and diversion trenches is readily implementable. Some coordination with regulatory agencies would be required in the disposal of contaminated or treated groundwater.

Alternative 7 would be difficult to implement, requiring placing and drilling large diameter collection sumps at the edges of 50 waste cells. Proper placement of the sumps would be difficult. Geophysics would be used to locate the waste cells, and pre-design investigation would be required to determine the topographic low point of each waste cell. There would be some difficulties in installing the liquid waste removal sumps at each waste cell in terms of achieving optimal placement and depth. Collecting liquids from the sumps would also be difficult and would require proper pumps and proper pump maintenance. The screens in the sumps may become clogged and require maintenance and/or replacement over time.

Cost

The excavation alternatives are the most expensive to implement, with a cost range of $27.7 million (Alternative 9a) to $61.2 million (Alternative 6). However, Alternative 9a is less than half the cost of the next less expensive excavation alternative (Alternative 4a at $56.9 million). The containment alternatives range from $7.3 million (Alternative 2) to $13.8 million (Alternative 3). Alternative 7 costs $22.5 million to implement. These costs represent net present worth of capital and O&M costs using a seven percent discount rate. Operation and maintenance for alternatives that leave waste in place (all except Alternatives 4 and 6) would need to occur indefinitely; although it was costed for only 30 years, consistent with U.S. EPA FS guidance.

State Acceptance

Ohio EPA recommends that U.S. EPA move forward with Alternative 4a as the selected remedy, not Alternative 9a, because Ohio EPA believes that Alternative 9a is inconsistent with the intent of CERCLA and the NCP.

Community Acceptance

Most of the community has not yet commented on Region 5’s preference for Alternative 9a to remediate the Barrel Fill. During the 2010 public comment period, a number of citizens commented against alternatives leaving hazardous waste in place; however, at that time, no alternatives such as Alternative 9a existed that would remove all liquid waste and leave solid hazardous and non-hazardous waste in place.

CF/WATER and CCCHD do not favor Alternative 9a. CF/WATER favors Alternative 4a. The PRPs believe that Alternative 9a meets the NCP’s evaluation criteria better than Alternative 4a.

25

10. Principal Threat Waste

The hazardous liquid containerized and uncontainerized waste in the Barrel Fill constitutes principal threat waste. Alternative 9a will remove all of the highly mobile, liquid principal threat waste for off-site treatment to reduce the toxicity, mobility, and volume. The solid hazardous waste and solid non-hazardous waste would be consolidated on-site in an engineered waste cell, where these wastes will be reliably contained. These wastes are not expected to cause contamination to the deep sand and gravel aquifer over time.

11. Recommended Alternative

The Region recommends selection of Alternative 9a: Excavation of All Waste; Off-site Disposal and Treatment of Liquid Waste; and Consolidation of Solid Hazardous and Non-hazardous Waste in an On-site, Engineered Waste Cell be implemented. The estimated cost is $27,746,000. Major activities include:

Excavate all waste; Dispose of and treat off-site all containerized and uncontainerized liquid waste; Build an engineered waste cell on-site; install leachate collection and leakage

collection systems beneath the consolidated waste; consolidate solid hazardous and non-hazardous waste into the cell; construct a RCRA-compliant waste cap over the waste;

Build a slurry wall around the consolidated waste; Perform groundwater monitoring; and Implement institutional controls.

The selected remedy must meet the threshold criteria of Overall Protection of Human Health and the Environment and Compliance with ARARs (unless an available ARAR waiver is exercised) [300.430(f)(1)(ii)(A) and (B)]. Alternative 9a meets these threshold criteria.

The selected remedy must be cost-effective as evidenced by both meeting the two threshold criteria and by assessing three of the five balancing criteria: Long-term Effectiveness and Permanence; Reduction of Toxicity, Mobility or Volume Through Treatment; and Short-Term Effectiveness [300.430(f)(1)(ii)(D)]. Alternative 9a is Long-Term Effective and Permanent. It provides long-term and permanent protection against release of Barrel Fill contaminants to the nearby surface water and deep sand and gravel drinking water aquifer. Alternative 9a provides for treatment of the Barrel Fill highly mobile, liquid waste and relies on on-site containment of the re-consolidated solid hazardous and non-hazardous wastes. It provides short-term effectiveness when proper health and safety measures are taken.

Alternative 9a utilizes permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable, as evidenced by meeting the two threshold criteria and offering the best balance of trade-offs between the alternatives in terms of the five primary balancing criteria. This balancing emphasizes Long-Term Effectiveness and Reduction of Toxicity, Mobility or Volume Through Treatment. The modifying criteria, State Acceptance and Community Acceptance, will also be considered [300.430(f)(1(ii)(E)].

26

In summary, Alternative 9a meets the two threshold criteria. It is comparable to the other excavation alternatives in terms of Long-Term Effectiveness and Permanence, Short-Term Effectiveness and Implementability. It provides treatment of all of the highly mobile, liquid principal threat waste and reliably contains the solid hazardous and non-hazardous waste in an ideal geologic setting for containment. Its cost is less than half of the next less expensive excavation alternative. State Acceptance and Community Acceptance will be fully evaluated by Region 5 after the close of the upcoming public comment period.

12. ARARs

A list of ARARs is shown in Table 3.

13. Technical & Policy Issues

There are no technical or policy issues associated with implementation of Alternative 9a, other than those mentioned previously. Collection, disposal, and treatment of liquid waste would involve coordination with regulatory agencies and local officials as is typical when this type of operation occurs.

14. Cost Information

Cost estimate summaries are shown in Table 4 for the remedial alternatives. Tables 5-9 show detailed cost estimates for the largest cost components of Alternative 9a.

15. Letters and Position Papers from Ohio EPA and Other Stakeholders

See Attachments 1-5.

27

 

Surface Water(mg/L)

Groundwater (mg/L)

Soil (mg/kg)

Potable Use(mg/L)

Volatile Organic Compounds1,1,1-Trichloroethane - - - 2.00E-011,1-Dichloroethane - - - 2.40E-031,1-Dichloroethene 2.10E-01 2.10E-01 6.20E-02 7.00E-031,2,4-Trichlorobenzene - - - 7.00E-021,2-Dichlorobenzene 2.30E-02 2.30E-02 3.10E-02 6.00E-011,3-Dichlorobenzene 2.20E-02 2.20E-02 3.00E-02 1.80E-011,4-Dichlorobenzene 9.40E-03 9.40E-03 1.30E-02 7.50E-021,2-Dichloroethane - - - 5.00E-032-Butanone 2.20E+01 2.20E+01 2.70E+00 7.10E+002-Hexanone - - - 4.70E-024-Methyl-2-pentanone - - - 2.00E+00Acetone - - - 2.20E+01Benzene 1.60E-01 1.60E-01 3.90E-02 5.00E-03Carbon disulfide 1.50E-02 1.50E-02 4.20E-03 1.00E+00Chloroethane - - - 2.40E+01Chloroform (Trichloromethane) 1.40E-01 1.40E-01 2.80E-02 8.00E-02Chloromethane - - - 1.90E-01cis-1,2-Dichloroethene - - - 7.00E-02Dichlorodifluoromethane (CFC-12) - - - 3.90E-01Ethylbenzene 6.10E-02 6.10E-02 5.20E-02 7.00E-01Isopropylbenzene 4.80E-03 4.80E-03 2.80E-03 6.80E-01Methyl cyclohexane - - - 5.20E+00Methylene chloride 1.90E+00 1.90E+00 2.70E-01 5.00E-03Tetrachloroethene 3.60E-02 3.60E-02 1.70E-02 5.00E-03Toluene 6.20E-02 6.20E-02 3.10E-02 1.00E+00trans-1,2-Dichloroethene - - - 1.00E-01Trichloroethene 2.20E-01 2.20E-01 1.00E-01 5.00E-03Trichlorofluoromethane (CFC-11) - - - 1.30E+00Vinyl chloride 1.60E-02 1.60E-02 3.40E-03 2.00E-03Xylene (total) 2.70E-02 2.70E-02 2.60E-02 1.00E+01

Table 1, page 1 of 2: Surface Water, Groundwater, and Potable Use Cleanup Goals for Alternative 9a

28

Surface Water(mg/L)

Groundwater (mg/L)

Soil (mg/kg)

Potable Use(mg/L)

Semi-volatile Organic Compounds2-Methylnaphthalene - - - -2-Methylphenol 6.70E-02 6.70E-02 2.00E-02 1.80E+004-Chloro-3-methylphenol - - - -4-Methylphenol 5.30E-02 5.30E-02 1.60E-02 1.80E-01Acetophenone - - - 3.70E+00Benzaldehyde - - - 3.70E+00Biphenyl 6.50E-03 6.50E-03 1.00E-01 1.80E+00bis(2-Ethylhexyl)phthalate 8.40E-03 8.40E-03 2.50E+02 6.00E-03Butyl benzylphthalate 2.30E-02 2.30E-02 2.60E+00 3.50E-02Diethyl phthalate 2.20E-01 2.20E-01 1.50E-01 2.90E+01Di-n-butylphthalate - - - 3.70E+00Caprolactam - - 1.80E+01Naphthalene 2.10E-02 2.10E-02 5.20E-02 1.40E-04N-Nitrosodiphenylamine - - - 1.40E-02Pentachlorophenol 9.20E-03 9.20E-03 1.20E-02 1.00E-03Phenol 1.60E-01 1.60E-01 2.80E-02 1.10E+01PesticidesDieldrin 5.60E-05 5.60E-05 2.40E-03 4.20E-06Heptachlor - - - 4.00E-04Methoxychlor - - - 4.00E-02MetalsAluminum - - - 3.70E+01Antimony - - - 6.00E-03Arsenic - - - 1.00E-02Barium - - - 2.00E+00Cadmium 1.80E-01 1.80E-01 4.50E+00 5.00E-03Chromium - - - 1.00E-01Cobalt 2.40E-02 2.40E-02 3.60E-01 1.10E-02Copper 3.20E-02 3.20E-02 3.70E-01 1.30E+00Iron - - - 2.60E+01Lead 3.90E-02 3.90E-02 1.20E+01 1.50E-02Manganese - - - 8.80E-01Mercury 9.10E-04 9.10E-04 1.70E-02 2.00E-03Nickel 1.70E-01 1.70E-01 3.80E+00 7.30E-01Selenium 5.00E-03 5.00E-03 8.90E-03 5.00E-02Silver 6.00E-05 6.00E-05 1.70E-04 1.80E-01Thallium - - - 2.00E-03Vanadium - - - 1.80E-01Zinc 4.00E-01 4.00E-01 8.30E+00 1.10E+01

Table 1, page 2 of 2: Surface Water, Groundwater, and Potable Use Cleanup Goals for Alternative 9a

29

Alternative Major Components Time to Complete Construction

Estimated Costs

1. No Action no remedial components None None

2. 2 downgradient groundwater collection trench with on-site groundwater treatment system or off-site disposal at a POTW

1 year $7.3M

3. 3 Alternative 2 with an upgradient groundwater diversion structure

1 year $13.8M

4. 4 waste removal and transport to a treatment, storage, and disposal facility (TSDF) or solid waste facility, as appropriate

1.50 years $60.6M

5. 4a Alternative 4 except that non-hazardous drummed waste and non-hazardous soils would be placed in an unlined waste cell in the Barrel Fill

1.75 years $56.9M

6. 4b Alternative 4 except that non-hazardous drummed waste and non-hazardous soils would be placed in a lined waste cell in the Barrel Fill

1.92 years $59.1M

7. 5 waste removal; on-site treatment (via HTTD and stabilization) of hazardous soils and residuals, and replacement of treated soils and residuals into a waste cell in the BF; off-site disposal and treatment of drummed waste, uncontainerized waste, cell water, and LNAPL

2.00 years $60.5M

8. 5a Alternative 5 except that non-hazardous drummed waste and non-hazardous soils would be placed in an unlined waste cell in the Barrel Fill

1.92 years $57.4M

9. 5b Alternative 5 except that non-hazardous drummed waste non-hazardous soils would be placed in a lined waste cell in the Barrel Fill

2.08 years $60.6M

10. 6 Alternative 5, except that HTTD-treated soil is transported off-site to a solid waste landfill

1.75 years $61.2M

11. 7

12. 9a

Alternative 3 with the addition of liquid waste removal sumps and portable pumps, and liquid waste disposal and treatmentExcavate all waste; dispose of and treat all liquid waste off-site; consolidate all solid hazardous and non-hazardous waste in an engineered waste cell on-site

1.33 years

1.50 years

$22.5M

$27.7M

Table 2: Tremont City Barrel Fill Site Remedial Alternatives

30

Table 3, page 1 of 6: ARARs and TBCs for the Barrel Fill Remedial Alternatives

31

Table 3, page 2 of 6: ARARs and TBCs for the Barrel Fill Remedial Alternatives

32

Table 3, page 3 of 6: ARARs and TBCs for the Barrel Fill Remedial Alternatives

33

Table 3, page 4 of 6: ARARs and TBCs for the Barrel Fill Remedial Alternatives

34

Table 3, page 5 of 6: ARARs and TBCs for the Barrel Fill Remedial Alternatives

35

Table 3, page 6 of 6: ARARs and TBCs for the Barrel Fill Remedial Alternatives

36

  ITEM DESCRIPTION RA-1 RA-2 RA-3 RA-4 RA-4A RA-4B RA-5 RA-5A RA-5B RA-6 RA-7 RA-9aCAPITAL COSTA Fencing and Signage $0 $103,000 $103,000 $103,000 $103,000 $103,000 $103,000 $103,000 $103,000 $103,000 $103,000 $103,000B Groundwater Extraction Trench $0 $1,065,000 $1,065,000 NA NA NA NA NA NA NA $1,065,000 NAC Groundwater Treatment System $0 $912,000 $912,000 NA NA NA NA NA NA NA $912,000 NAC1 Groundwater Diversion (upgradient) $0 NA $6,530,000 NA NA NA NA NA NA NA $6,530,000 NAD Groundwater Monitoring $0 $991,000 $991,000 $300,000 $452,000 $452,000 $452,000 $452,000 $452,000 $300,000 $991,000 $991,000E Institutional Controls $0 $25,000 $25,000 $25,000 $25,000 $25,000 $25,000 $25,000 $25,000 $25,000 $25,000 $25,000F Surface Water Relocation $0 $79,000 $79,000 NA $79,000 $79,000 $79,000 $79,000 $79,000 NA $79,000 NAG Surficial Grading/Vegetation $0 $517,000 $517,000 $308,000 $517,000 $517,000 $517,000 $517,000 $517,000 $308,000 $517,000 $517,000H1 On-Site Disposal $0 NA NA NA $1,410,000 $3,650,000 $4,700,000 $1,971,000 $5,176,000 NA NA $3,438,000I1 Waste Material Handling $0 NA NA $59,225,000 $53,084,000 $53,084,000 $53,396,000 $52,941,000 $52,941,000 $59,866,000 NA $10,771,000I2 Off-Site Disposal $0 NA NA NA NA NA NA NA NA NA NA $4,616,000J Liquid Waste Sumps (including disposal of liquid waste) $0 NA NA NA NA NA NA NA NA NA $5,433,000 NAK Slurry Wall $0 NA NA NA NA NA NA NA NA NA NA $1,682,000L Leak Collection System $0 NA NA NA NA NA NA NA NA NA NA $491,000

TOTAL CAPITAL COST: $0 $3,692,000 $10,222,000 $59,961,000 $55,670,000 $57,910,000 $59,272,000 $56,088,000 $59,293,000 $60,602,000 $15,655,000 $22,634,000

OPERATION AND MAINTENANCEA Fencing and Signage $0 $2,000 $2,000 $2,000 $2,000 $2,000 $2,000 $2,000 $2,000 $2,000 $2,000 $2,000B Groundwater Extraction Trench $0 $13,000 $13,000 NA NA NA NA NA NA NA $13,000 NAC Groundwater Treatment System $0 $126,000 $126,000 NA NA NA NA NA NA NA $126,000 NAD Surface Water Relocation $0 $2,000 $2,000 NA $2,000 $2,000 $2,000 $2,000 $2,000 NA $2,000 NAG Surficial Grading/Vegetation $0 $9,000 $9,000 NA $9,000 $9,000 $9,000 $9,000 $9,000 NA $9,000 $9,000H1 On-Site Disposal $0 NA NA NA $9,000 $9,000 $12,000 $13,000 $13,000 NA NA $13,000J Liquid Waste Sumps $0 NA NA NA NA NA NA NA NA NA $259,000 $239,000L Leak Collection $0 NA NA NA NA NA NA NA NA NA NA $10,900

TOTAL ANNUAL O&M COST $0 $152,000 $152,000 $2,000 $22,000 $22,000 $25,000 $26,000 $26,000 $2,000 $411,000 $273,900

NET PRESENT WORTH OF O&M COST $0 $1,886,000 $1,886,000 $15,000 $273,000 $273,000 $310,000 $323,000 $323,000 $15,000 $5,100,000 $3,399,000

Net Present Worth of Groundwater Monitoring $0 $1,713,000 $1,713,000 $580,000 $940,000 $940,000 $940,000 $940,000 $940,000 $580,000 $1,713,000 $1,713,000

Total Net Present Value of O&M and GW Monitoring $0 $3,599,000 $3,599,000 $595,000 $1,213,000 $1,213,000 $1,250,000 $1,263,000 $1,263,000 $595,000 $6,813,000 $5,112,000

NET PRESENT WORTH OF TOTAL COST $0 $7,291,000 $13,821,000 $60,556,000 $56,883,000 $59,123,000 $60,522,000 $57,351,000 $60,556,000 $61,197,000 $22,468,000 $22,746,000  (CAPITAL PLUS O&M)                      

Table 4: Cost Summary of the Tremont City Barrel Fill Site Remedial Alternatives

37

Table 5: Capital Cost Estimate of the Waste Material Handling Component of Alternative 9a

38

Table 6: Capital Cost Estimate of the Off-Site Disposal Component of Alternative 9a

39

Table 7: Capital Cost Estimate of the Engineered Waste Cell Component of Alternative 9a

40

Table 8: Capital Cost Estimate of the Slurry Wall Component of Alternative 9a

41

Table 9: Capital Cost Estimate of the Groundwater Monitoring Component of Alternative 9a

42

Attachment 1: Position Paper from Ohio EPA to U.S. EPA

43

44

45

46

47

48

49

50

51

Attachment 2: December 29, 2010 E-mail from the Community Advisory Group

(“CF/WATER”) to U.S. EPA

Ron:

I have reviewed the new material and consider this proposal to be new. Therefore, since I feel that it does not meet the nine evaluation criteria; especially the keystone criteria of "Overall protection of Human Health and the Environment", this proposal is not a viable remediation method. As previously stated in prior communication, CF/Water endorses alternative 4a as the best method to meet the 9 criterion. If Region 5 is actually considering this new proposal, at the very least there should be a new public comment period and public hearing to inform the public at large in Clark County( and Champaign as well) of the real dangers inherent in leaving principal waste in the ground above one of the largest active aquifers in the US.

Jeff Briner, CF/Water Chairman

52

Attachment 3: Letter from the Clark County Combined Health District to U.S. EPA

53

54

55

Attachment 4: Letter from Chemical Waste Management (a member of RESA)to U.S. EPA

56

57

58

59

60

61

62

63

64

65

Attachment 5: Letter from the RI/FS Performing Respondents (“RESA”) to U.S. EPA

66

67