US EPA RECORDS CENTER REGION 5

476647 VELSICOL BURN PIT SUPERFUND SITE PROPOSED PLAN FOR OPERABLE UNIT 1 ST. LOUIS, MICHIGAN

Community Participation This Proposed Plan identifies the Preferred Alternative for addressing contaminated soil The EPA and MDEQ provide information and groundwater at Operable Unit 1 (source regarding the cleanup of the Velsicol Burn Pit material) at the Velsicol Burn Pit in St. Louis, Superfund site through public meetings, the Michigan (VBP or site) and provides the Administrative Record for the site, and rationale for this preference. In addition, this announcements published in the Morning Sun. Proposed Plan includes summaries of other The EPA and MDEQ encourage the public to gain a more comprehensive understanding of cleanup alternatives evaluated for use at this the site and the Superfund activities that have site. This document is issued by the United been conducted at the site. Additional States Environmental Protection Agency information can also be found at the EPA (EPA), in conjunction with the Michigan Regions 5's web site located at Department of Environmental Quality http://www.epa.gov/region5/cleanup/velsicolbur npit/. A citizens group called the Pine River (MDEQ). The MDEQ was the lead Agency for Superfund Citizen Task Force also has a web the initial Remedial Investigation (Rl) and the page containing a large amount of site EPA has been the lead agency for the Rl information and it can be located at addendum and Focused Feasibility Study www.pinerivercag.org. (FFS) and will be the lead Agency for the The Administrative Record, which contains the Proposed Plan, Record of Decision, Remedial information used to develop the site remedy, is Design, and Remedial Action. The EPA, with at the following location: input from the MDEQ, will select the final Public Library remedy for the site after reviewing and T.A. Cutler Memorial Library considering all information submitted during 312 Michigan Avenue the pubhc comment period. The public St. Louis, MI comment period will run 30 calendar days The public comment period will run for a pursuant to Section 300.430 (f)(3)(i) of the from November 24, 2014 to January 2,2015 National Oil and Hazardous Substances and the EPA will be accepting comments on the Proposed Plan during the public comment Pollution Contingency Plan (NCP), 40 C.F.R. § period. Written comments can be sent to the 300.430(f) (3) (i). The public comment period following address: will begin on November 24,2014 and end on Jena Sleboda Braun January 2,2015. The EPA, in consultation with Remedial Project Manager MDEQ, may modify the Preferred Alternative United States Environmental Protection Agency or select another response action presented in Mail Code SR-6I 77 W. Jackson Blvd. Chicago, IL 60604 this Proposed Plan based on new information slebodaj [email protected] or public comments. A public meeting will be held on December 3, 2014 to discuss all the alternatives and the The EPA is issuing this Proposed Plan to fulfill preferred remedial alternative. Written and oral comments will be accepted at the meeting. The its obligations under the Comprehensive meeting will be held at the following time and Environmental Response, Compensation, and location: Liability Act (CERCLA) Section 117(a), 42 December 3,2014 U.S.C. § 9617(a), and as part of its pubhc 6:30 PM to 9:00 PM participation responsibilities under NCP T. S. Nurnberger Middle School Section 300.430(f)(2), 40 C.F.R. § 300.430(f)(2). 312 Union St., St. Louis, MI This Proposed Plan summarizes information that can be found in greater detail in the Rl, Rl Addendum, FFS reports, and other documents contained in the Administrative Record file for this site. The Administrative Record is located at the T. A. Cutler Memorial Library, 312 Michigan Avenue, St. Louis, Michigan and at the EPA Region 5 Records Center, 77 West Jackson Boulevard, Chicago, Illinois. The library hours of operation are Monday, Tuesday, and Thursday from 10:00 AM to 7:00 PM, Wednesday and Friday from 10:00 AM to 5:00 PM, and Saturday from 10:00 AM to 2:00 PM. The library is closed on Sunday. The EPA and MDEQ encourage the public to review these documents to gain a more comprehensive understanding of the site and Superfund activities that have been conducted at the site.

Five remedial alternatives were evaluated for the Velsicol Burn Pit Site in the Focused Feasibility Study (FSS). They include the No Action Alternative, Soil Containment and Capping, In Situ Stabilization and Soil Cover, In Situ Thermal Treatment and Soil Cover, and Hot Spot Excavation and Disposal. For the reasons explained below, the EPA's preferred alternative for the site is Alternative 4: In Situ Thermal Treatment and Soil Cover.

I. SITE BACKGROUND From 1978 through 1983 and before inclusion of the site on the National Priorities List (NPL), a preliminary assessment, site inspection, and site characterization investigation were performed by the EPA and MDEQ. In response to investigation findings and in fuhillment of a 1982 Consent Judgment remedy, approximately 68,000 cubic yards of contaminated material was removed from the VBP, transferred to the Former Plant Site (FPS), and placed for disposal beneath a compacted clay cap. From 2004 to 2006, the MDEQ continued characterization work at the VBP to evaluate the presence of residual contamination related to historical waste disposal. Initially, the MDEQ advanced 10 hydraulic direct-push (HDP) borings to the regional till unit beneath the VBP and adjacent area. The MDEQ collected soil and groundwater samples from the HDP borings. The soil and groundwater data confirmed the presence of contaminants, including volatile organic compounds (VOCs), semivolatile organic compounds, pesticides, inorganic compounds, and para chlorobenzene sulfonic acid (pCBSA). Subsequently, the MDEQ installed 5 additional HDP borings, 13 shallow monitoring wells, 6 intermediate monitoring weUs, and 4 deep monitoring wells to complete the initial phase of the investigation. The MDEQ groundwater sampling results from temporary wells at boring locations BA-2 and BA-10 revealed the presence of non-aqueous phase liquid (NAPL); the MDEQ subsequently installed permanent monitoring well clusters at these locations (Rl Addendum Report, CH2M HILL 2013).

In 2009, the MDEQ conducted an additional site investigation at the VBP that identified contaminated soil and groundwater within the shallow unit including VOCs, semivolatile organic compounds, pesticides, polybrominated biphenyls, pCBSA, and inorganic compounds. Chemicals were detected at concentrations exceeding one or more of the MDEQ's Part 201 generic criteria in the shallow unit. As concluded in the 2009 Rl addendum report (Weston Solutions of Michigan, Inc. 2009), however, VOCs are the predominant compounds present beneath the VBP in terms of the frequency detected and the observed concentration. The investigation also confirmed the presence of NAPL in monitoring wells BA-2S and BA- 10S. Light and dense NAPL are present at the VBP. The light NAPL is primarily comprised of benzene, and the dense NAPL is primarily comprised of 1,2-dichloroethane (1,2-DCA). However, both light and dense NAPL also contained l,2-dibromo-3-chloropropane, dichlorobenzene, trichloroethylene, and trace amounts of other VOCs. The NAPL composition is consistent with chemicals identified in site soil and groundwater during historical site investigations that exceed the MDEQ's Part 201 standards. Collectively, the compounds and the specialty chemicals previously noted form the basis for identification of VBP contaminants of concern (COCs). In 2012, CH2M HILL, a contractor for the EPA, conducted additional site investigation activities at the VBP to eliminate data gaps and to further define the nature and extent of NAPL and COC impacts to soil and groundwater in the shallow unit underlying and downgradient of the VBP. These more recent site investigation findings are being used in conjunction with previous Rl findings to assess risks to human health and the environment, and to support the selection of a remedy that eliminates, reduces, or controls the risks. The 2012 Rl findings are detailed in the 2013 Rl addendum report (CH2M HILL 2013).

A. Relationship between the Velsicol Burn Pit and the Former Plant Site The VBP is related to the Former Plant Site (FPS). The VBP was an offsite disposal area, operated by Velsicol Chemical Corporation (Velsicol), where industrial wastes were burned for volume reduction or other disposal purposes. During plant operation, solid and liquid waste from the FPS was burned at the VBP. In addition, solid waste from the City of St. Louis was also burned at this location. According to records, liquid waste was burned weekly in an open pit. The VBP was proposed for the National Priorities List (NPL) in the early 1980s. However, prior to final Hsting of the VBP, Velsicol excavated the VBP and disposed of the waste from the VBP at the FPS in accordance with a cleanup plan for the FPS required under the 1982 Consent Judgment. The MDEQ historically considered the VBP a part of the Velsicol Chemical Corporation Superfund Site (currently EPA ID#MID000722439). Previous Rl data for the VBP was published in the Rl report documents for the FPS (Remedial Investigation Report for Operable Unit One Velsicol Chemical Corporation Superfund Site, St. Louis, Gratiot County, Michigan [Weston Solutions of Michigan, Inc. 2006] and Remedial Investigation Addendum Report for Operable Unit One Velsicol Chemical Corporation Superfund Site, St. Louis, Gratiot County, Michigan [Weston Solutions of Michigan, Inc. 2009]). Because the VBP had been proposed for the National Priorities List previously, the EPA requested information pertaining to the VBP be removed from the draft FS. The VBP site was re-evaluated and EPA scored the VBP for final Usting on the National Priorities List as a separate site. In March 2010, the VBP (then referred to as the Gratiot County Golf Course) was placed on the National Priorities List due to residual contamination (75 Federal Register 9782 (March 4, 2010)).

B. Enforcement Activities Prior to the site's listing on the National Priorities List, a number of pre-NPL responses were conducted from 1978 through 1983, mduding site characterization investigations, site inspections, a preliminary assessment, and mterim remedial actions. During the 1982 Consent Judgment remedy, approximately 68,000 cubic yards of contaminated material was removed from the VBP, and then transferred to and placed beneath the cap at the FPS. Velsicol was the owner of the site and burned its waste from its main chemical manufacturing plant on the other side of the Pine River at the VBP. Velsicol is responsible for the contamination at the site. In 1999, a successor of Velsicol filed for bankruptcy. As part of a settlement of that bankruptcy action, a trust, known as the Velsicol Chemical Corporation St. Louis Trust Account (Bankruptcy Trust), was created to hold approximately $16 million for the EPA to use to complete the remedial action occurring at the Velsicol Chemical Corporation Site in St. Louis, Michigan. In addition, the bankruptcy settlement transferred ownership of a parcel within the site from Velsicol to a Custodial Trust that currently holds title to this parcel. There are no funds in the Bankruptcy Trust dedicated for the VBP site and the EPA will use all of the money available in the Bankruptcy Trust in the ongoing remedial action at the FPS. Therefore, there are no viable PRPs or currently available funds for this site, and fhe site is being addressed as Fund lead.

C. Previous Public Engagement The EPA has participated in multiple Teclrnical and Community meetings of the Pine River Superfund Citizen Task Force, and has presented information from the Rl, Human Health and Ecological Risk Assessments, and the FFS during these meetings. The EPA has also provided the Pine River Superfund Citizen Task Force with electronic copies of these documents, and has responded to previous comments submitted by the Pine River Superfund Citizen Task Force.

II. SITE CHARACTERISTICS

The VBP site is approximately 5 acres in size and is located in a low-lying area in the northwest portion of the City of St. Louis, Michigan. It is located approximately 1,200 feet northwest of the Pine River, within the boundary of the Hidden Oaks Golf Course, across the river from the Velsicol Chemical Corporation Superfund Site. The site location is depicted in Figure 1. The address for fhe Hidden Oaks Golf Course is 1270 West Monroe Road, St. Louis, Michigan. The conceptual site model for the VBP is shown in Figure 5.

A. Summary of Remedial Investigation As described above, an Rl was conducted by MDEQ from 2004 to 2006. The objectives of the Rl were to evaluate the presence of residual contamination related to historical waste disposal. The results of the Rl are summarized in the following subsections.

1. Current Conditions Land use near the VBP is a mixture of recreational (golf course) and residential. There are nine nearby private drinking water wells that are currently in use.

2. Assessment of Potential Future Use The current land use for the VBP (recreational—golf course) and the adjacent (residential) area is expected to continue in the future. Groundwater use near fhe site is not expected in the future because the City of St. Louis is currently partnering with the Gratiot Area Water Authority to develop and supply a new municipal water source. Furthermore, the shallow unit is not a high producing aquifer and would not be a reliable source of water for a private well. The deeper aquifer is within the capture zone of the Velsicol Chemical Corporation Superfund site, and wells in this deeper aquifer are restricted. It is also anticipated that the City of St. Louis will soon pass an ordinance restricting new private groundwater wells within the city limits.

3. Climate Gratiot County has a continental climate typical of central Michigan (Weston Solutions of Michigan, Inc. 2006). The region typically has warm to hot summers and cold winters, with July being the hottest month and January being the coldest. Although it peaks in the summer, precipitation is well distributed throughout the year. Based on records spanning from 1961 through 1990, the average maximum temperature in Alma, Michigan, in January is 27.9 degrees Fahrenheit (°F) (-2.3 degrees Celsius [°C]) and 83.1°F (28.4°C) in July. Between 1931 and 1995, the average annual precipitation is 30.4 inches, with approximately 62 percent falling from April through September.

4. Topography The approximate elevation of the City of St. Louis is 738 feet above mean seal level (amsl). According to a Soil Survey of Gratiot County, Michigan, the topography of Gratiot County was sculpted during Wisconsin-stage glaciations (United States Department of Agriculture, Soil Conservation Service 1979). The VBP topography is characterized as gently rolling hills with occasional ridges and elevations ranging from approximately 760 to 770 feet amsl.

5. Regional Geologic and Hydrologic Setting The regional geology and hydrogeology of the St. Louis area and local conditions beneath the VBP site are described in greater detail in the Rl report (Weston Solutions of Michigan, Inc. 2006). Key excerpts from this document are presented in the following subsections. a) Regional Geology Glacial processes formed surficial landforms during the Wisconsin stage, which ended 10,000 to 12,000 years ago. The surficial geology of the St. Louis area is characterized by glacial moraines, till and outwash plains, and outwash channels. The Owosso Moraine extends in a north-south direction through the center of the county. The West Branch Moraine extends in the same general direction and is located along the western boundary of the Gratiot County line. According to the map Quaternary Geology of Michigan (Farrand and Bell 1982), glacial deposits in the St. Louis area are composed of end moraine medium- textured glacial till. The glacial till is described as gray, grayish brown, or reddish brown, non-sorted glacial debris. The matrix is composed predominantly of loam and silt loam with variable amounts of cobbles and boulders. Small areas of coarser or finer-textured till and small areas of outwash are also included in the deposit. The deposits occur in narrow linear belts of hummocky relief marking former pauses in ice sheet movement.

According to the Soil Survey for Gratiot County (USDA Soil Conservation Service 1979), the thickness of glacial deposits is highly variable and ranges from 50 to 500 feet. Based on local well logs and boring logs prepared from previous investigations, the thickness of glacial deposits near the VBP range from approximately 260 to 280 feet. Underlying the unconsolidated glacial deposits are Jurassic "Red Beds/' which consist of a series of yellow- tan to purplish- red stained sandstones and gypsum beds intercalated in red and greenish- grey shales. The bedrock surface elevation underlying the VBP ranges between 396 and 456 feet amsl, approximately 280 feet below ground surface (bgs). b) Hydrogeology Rl activities at the VBP area have been Kmited to the following three hydrogeological units: the shallow unit/the till unit, and the lower unit. i. Shallow Unit Data obtained during previous Rl and the 2012 Rl activities indicate there are several water­ bearing lenses within the shallow unit, consisting of confined/ unconfined interbedded silty to clayey sands and silty clays. The lenses were deposited by glacial processes and/or the Pine River and range in thickness from less than a foot to greater than 15 feet. The 2012 Rl data confirmed the upper lenses are generally perched and apparently pinch out radially from the VBP at lower elevations. The perched water lenses are considered a "component" of the shallow unit with some unique characteristics. Depth to groundwater measurements in monitoring wells screened within the shallow unit range from 2 to 29 feet bgs (elevations of 738 to 754 feet amsl). Groundwater flow in the shallow unit is variable, depending on the areal location and screened depth interval of each well. The groundwater flow direction in the shallow unit in the VBP is predominantly southeast toward the Pine River. However, the general surface topography of the VBP appears to control perched water movement in the upper portion of the shallow unit within and downgradient of the VBP. The perched water apparently moves northwest, although recent chemical data indicate that the groundwater flow velocity and contaminant transport diminishes near the north-northwestern excavation limit of the VBP, which may be caused by a number of factors, including a pinchout of the perched lens or areas where the 1982 excavation activities resulted in the perched unit combining with the shallow unit in the west-central VBP. Therefore, the major components influencing groundwater flow direction appear to be topography and fhe Pine River. Groundwater flow velocity estimates in this unit range from 1.09 to 1.49 feet per day (397.9 to 543.9 feet per year; Weston Solutions of Michigan, Inc. 2009). ii. Till Unit Between the shallow and lower units is a lower permeability till unit that consists of silt with variable amounts of sand, gravel, and clay. The unit is not considered a significant water-producing unit. However, interbedded sand and gravel seams, typically 1 foot or less, but up to 5 feet thick, are present and occasionally capable of providing a sufficient volume of water for collection of groundwater samples. Water-bearing seams within the till unit are identified as a hydrostratigraphic unit underlying the VBP. The till unit is characterized as leaky semiconfirdng layers composed of layers of low-permeability silt and clay intercalated with interconnected sand lenses which are capable of slowly tiansmitting groundwater from the shallow unit to the lower unit. Water-bearing seams in the upper till unit are hydraulically connected to the Pine River in some areas. Near the VBP, groundwater in the upper till unit water-bearing seams generally flows east toward the Pine River and to low areas located to the west, which indicates a hydraulic connection between the till unit, shallow unit, and the Pine River. Groundwater flow directions in the till unit water-bearing seams underlying the VBP are similar to those in the shallow water-bearing units, with the topography and the nearby surface water features influencing the groundwater flow. Groundwater flow is to the southeast toward the Pine River in the eastern part of the VBP, and to the west and southwest in the western part of the VBP. iii. Lower Unit Underlying the till unit at approximately 50 to 80 feet bgs is the third primary hydrostratigraphic unit, referred to as the lower unit. The unit consists of interbedded sands, silts, and clayey to silty sands, which may extend to approximately 260 feet bgs. A review of the water supply well logs for the City of St. Louis wellfield, which is approximately one mile away, indicated that each of the wells are screened in the deep portion (aquifer) of the lower unit at elevations ranging from 507 to 548 feet amsl. The aquifer appears to be separated from the upper portions of the lower unit by one or more lower permeability silty or clayey units. iv. Hydrology—Pine River and Northwest Drainage Ditch According to information obtained from the Michigan Department of Natural Resources and the Hydrogeologic Atlas of Michigan (Western Michigan University, Department of Geology 1981), the northern section of Gratiot County is located within the Tittabawassee River Drainage Basin. All surface waters within this basin eventually discharge into the Tittabawassee River, which flows into the Saginaw River, and ultimately into Lake Huron at Saginaw Bay. The primary surface water feature near the VBP is the Pine River, located approximately 1,200 feet southeast of the VBP. The Pine River flows to the northeast from the site and converges with the Chippewa River approximately 30 miles downstream to the northeast. The Chippewa River flows into the Tittabawassee River. Surface water runoff from the VBP mainly flows northwest to west foUowing the general sloping topography, and eventually discharges into an intermittent drainage ditch to the northwest. The drainage ditch also collects surface water runoff from a nearby golf course fairway. The drainage ditch is typically dry, except for short periods after storm events. Therefore, it does not appear to be a discharge point for perched groundwater from the VBP. The calculated hydraulic gradient of the perched groundwater between monitoring wells BA-5S and BA12 and interpolation of the hydraulic gradient from BA12 to the drainage ditch indicates the perched groundwater would flow beneath the bottom of the drainage ditch (elevation 739.03 feet amsl). v. Ecological Setting The VBP and surrounding area consists of abundant woodlands and is vegetated by short, shallow-rooted grass and some small trees. No regulated wetlands are present at the VBP, and the wildlife habitats consist of clear, open areas. The previously described drainage ditch is located adjacent to the north side of the VBP. Signs of small mammals and Canada geese have been observed near the VBP. Other wildlife present on or directly adjacent to the VBP includes various songbirds, reptiles, and mammals common to central Michigan. Threatened and endangered species are not expected onsite. 7. Nature and Extent of Contamination

Additional Rl activities were conducted for the VBP in 2012 to further delineate the nature and extent of contaminants, assess potential impacts to human health and ecological receptors, and close data gaps to support subsequent development of the FFS. The 2012 Rl activities confirmed that the majority of contamination in soil and groundwater is contained in the west-central and southern portion of the VBP.

VOCs (primarily benzene and 1,2-DCA) represent the primary COCs. Additional VOCs, pesticides, and several metals also have been identified in soil and groundwater at the VBP, but they are co-located within the extent of the benzene and 1,2-DCA-contaminated soil and groundwater. A Est of COCs for the VBP can be found in Table 1. With the exception of magnesium and selenium, the concentration of metals detected in soil is consistent with statewide default background levels and is within the typical range of data (central 95 percent) for each metal compared to soil samples collected by MDEQ as part the Michigan . Background Soil Survey of 2005. The contaminants in the shallow unit migrate with groundwater flow to the southeast. The extent of groundwater contamination has been delineated and is depicted in Figures 2 and 3. NAPL also has been identified at the VBP. The extent of NAPL has been fully delineated and is within the area that was excavated by Velsicol Chemical Corporation in 1982. The extent of NAPL is shown in Figure 4.

Separation of the perched water lenses and the shallow unit on the eastern portion of the VBP, and the hydraulic connection between the perched water lenses and the shallow unit on the western portion of the VBP, are supported by comparing VOC concentrations in groundwater samples from cluster wells CMW-1S/D, which are screened in the perched water lens and a shallow unit in an area not affected by the 1982 excavation. VOCs are not detected in the groundwater sample from well CMW-1S but there are significant concentrations in the groundwater sample from CMW-1D (greater than 15,000 micrograms per liter of total VOCs). However, VOCs are detected at both the perched groundwater elevation and in the shallow unit in the western portion of the VBP.

The groundwater-to-surface-water interface (GSI) transect wells confirm that the leading edges of the VOC plumes are greater than 500 feet from the Pine River (CH2M HILL 2013). The arsenic and selenium plumes depicted in the Rl are similar in shape and size to the VOC plumes. The GSI transect wells also indicate the leading edges of the dissolved arsenic and selenium plumes are greater than 500 feet from the Pine River. The total arsenic and selenium GSI exceedances in the groundwater samples collected from GSI transect wells are likely a result of the Geoprobe sampling methodology, since groundwater samples from nearby monitoring weUs WMW-28S, WMW-27S (excluding selenium), and WMW-50S were below GSI criteria (in accordance with MDEQ methodology, Geoprobe samples were not field filtered). The elevated metal concentrations are likely caused by particulates in borehole water samples, since there is no sand pack for filtration. Therefore, finer-grained particulates are allowed to pass through fhe temporary screen, where they would normally be removed by the filter pack, which results in higher metal concentrations in the water sample because the metal is adsorbed on the particulate, which is included in the total metals analysis. Groundwater samples collected from several monitoring wells at locations upgradient, within, and downgradient of the VBP indicate sulfate reduction may be occurring within VOC-impacted areas, and it appears conditions favorable for natural attenuation of contaminants may occur at some locations in the VBP.

Approximately 1,000 cubic yards of remnant burn pit ash/ debris is located southeast of the burn pit excavation area.

8. Principal Threat Waste

The EPA identifies a principal threat waste (source material) as "source material considered to be highly toxic or highly mobile that cannot be reliably contained or would present a significant risk to human health or the environment should exposure occur." NAPL is typically considered a principal threat waste. The objective of the membrane interface probe (MIP) portion of the Rl was to further define the extent of NAPL and use the data to select additional soil boring and monitoring well locations to delineate the extent of soil and groundwater impacts at the VBP. The initial MIP borings were located near the existing BA- 2 monitoring well cluster based on the historical presence of NAPL. Borings confirmed that subsurface soil and groundwater were heavily impacted at the BA-2 location, and NAPL was likely present. This NAPL is considered a principal threat waste at the VBP site.

III. SCOPE AND ROLE OF THE OPERABLE UNIT

To better understand and fuUy address the contamination at the VBP, the site has been divided into two operable units. The first operable unit (OU1) is closely associated with the former burn pit boundaries and encompasses the highest contaminant concentration, or source area. The second operable unit (OU2) is primarily associated with the groundwater contamination that occurs beyond the source area (OU1). Figure 6 shows the areal extent of the NAPL contamination and is considered the source area. Figures 2 and 3 show the groundwater contarnination occurring beyond the source area. OU2 will be addressed in a separate Proposed Plan and Record of Decision subsequent to the OU1 remedial action, after the effects of the OU1 remedial action on OU2 are determined. The ROD for OU2 will include a final groundwater remedy. This proposed plan addresses OU1.

IV. SUMMARY OF SITE RISKS

VOCs (primarily benzene and 1,2-DCA) represent the primary COCs (see Table 1). The human health risk assessment found that the risk and hazard drivers for the site are 1,2- dibromo-3-chloropropane, 1,2-dichloroethane (1,2,-DCA), benzene, and arsenic. The additional VOCs, pesticides, and several metals also identified in soil and groundwater at the VBP are co-located within the extent of the benzene and 1,2-DCA-contaminated soil and groundwater. With the exception of magnesium and selenium, the concentration of metals detected in soil is consistent with statewide default background levels and is within the typical range of data (central 95 percent) for each metal compared to sod samples collected by MDEQ as part of the Michigan Background Soil Survey of 2005. NAPL also has been identified at the VBP. The extent of NAPL has been fully delineated and is within the 1982 excavation limits.

1. Human Health Risk Summary

Current receptors, including recreational users (assumed to be golfers), site visitors (adolescent trespassers, hikers, birders, cross country skiers, etc.), grounds keepers who are potentially exposed to surface soils, and excavation workers (utihty or construction workers who may engage in intrusive activities) exposed to soils up to 10 feet bgs, are not expected to experience any site-related cancer risks or non-cancer hazards above de minimis levels, which are not generally deemed to be of concern by regulatory agencies.

If the site were to be converted to residential or light commercial or industrial use in the future, potential future residents or workers could experience unacceptable cancer risks and non-cancer hazards due to contact with contaminated soil, potential use of groundwater as drinking water, and inhalation of vapors inside residences or commercial/ industrial buildings that originated from subsurface soil and groundwater that infiltrated into occupied buddings. The Conceptual Site Model can be found in Figure 5.

The excess lifetime cancer risk and non-cancer hazard estimates for the site are summarized in Table 2. The estimates are expressed using one significant figure as recommended by EPA guidance. a) Current and Future Receptors

Recreational Users and Site Visitors As shown in Table 2, the estimated cancer risks and non-cancer hazards for these groups fall below the minimum levels (cancer risk > 1 x IO"6; non-cancer hazard > 1) generally considered to be of concern by regulatory agencies. Therefore, the estimated site related risks and hazards for these receptors are considered de minimis and of no concern to regulatory agencies.

Outdoor Workers (Groundskeepers) and Excavation Workers The estimated cancer risks for these receptors are 1 x 10-6, just equal to the lowest level that might be of potential concern to regulatory agencies. The non-cancer hazard estimates are one and two orders of magnitude below the lowest level of concern. Accordingly, the estimated risks and hazards to these receptors would generally not be of concern to the regulatory agencies. b) Potential Future Receptors

The VBP is located on, and is entirely surrounded by the Hidden Oaks Golf Course. However, the VBP area is not part of the actual course and is not maintained by the Course owner. Currently there is no active human use of the former burn area and that status does not appear likely to change in the future. Nevertheless, there is a residential area nearby and it is possible that the VBP area might be converted to residential, commercial or industrial use in the future. If the VBP site were to be converted to residential, commercial, or industrial use in the future, future residents or workers might be exposed to site contaminants through:

1. Direct contact with site soils (incidental soil ingestion, dermal contact with soil, and inhalation of particles and/ or vapors released from the soil to the ambient air);

2. Use of the site groundwater as drinking water (tapwater); and

3. Inhalation of vapors from site soil and groundwater that might infiltrate future residential structures (vapor intrusion).

If the site were to be converted to residential, commercial, or industrial use, pathways 1 and 3 would be complete. While site groundwater might be used as a source of drinking water, that exposure pathway is unlikely to be complete for several reasons:

• The water in the Shallow Outwash aquifer, where the bulk of the site-related contamination resides, is of poor quality (high dissolved solids), apart from the site- related contamination, and the aquifer is probably not sufficiently productive to serve as a reliable source of water for domestic or light commercial or industrial use.

• The area is served by a public water supply system that would provide a more dependable, better quality source of potable water.

• It is anticipated that as the local water system is upgraded, a local ordinance will be enacted prohibiting installation of new water supply wells and use of groundwater as a source of potable water.

Potential future risks and hazards have been estimated for all three potential exposure pathways (Table 2). The estimates were then summed for aU three potential exposure pathways, and for direct contact and vapor intrusion only, to evaluate both potential future exposure scenarios.

Potential Future Site Residents The cancer risk and non-cancer hazard estimates considering all three potential exposure pathways are unacceptable. The estimated cancer risk approaches 1 which indicates a near 100% probability that a receptor exposed to site contaminants in this way would develop cancer. Similarly, the non-cancer hazard index for these receptors is 9,000, nearly four orders of magnitude above the level considered acceptable (HI=1). This suggests that adverse non-cancer impacts to these receptors also would be highly likely. As shown in Table 2, the vast majority, 95 to 98%, of these estimated risks and hazards are due to use of site groundwater as drinking water. The risk and hazard drivers are l,2-dibromo-3- chloropropane, 1,2-dichloroethane, benzene, and arsenic.

If one assumes that site groundwater would not be used as a source of drinking water by potential future residents, the risk and hazard estimates are substantially lower, but still quite high - well above levels generally considered acceptable by regulatory agencies. Without use of site groundwater as a drinking water source, the estimated cancer risks to potential future site residents would be 6 x IO2 or 6 in 100, and the estimated non-cancer hazard index would be 500; still orders of magnitude above acceptable levels. The risk drivers remain much the same with somewhat different individual contributions.

Potential Future Indoor Commercial or Industrial Workers The risk and hazard estimates for potential future indoor workers are also quite high, but not quite as high as for potential future residents. Considering all three potential exposure pathways, the estimated cancer risk for these workers would be 3 x 10-1 or 3 chances in 10. The estimated noncancer hazard index would be 2,000. Again, the risk and hazard drivers are l,2-dibromo-3-chloropropane, 1,2-dichloroethane, benzene and arsenic.

If one assumes that site groundwater would not be used as a source of drinking water by potential future commercial or industrial facilities, the risk and hazard estimates for workers at such facilities would again be substantially lower, but still quite high. Without use of site groundwater as a drinking water source, the estimated cancer risks to potential future site workers would be 1 x 10-2 or 1 in 100, and the estimated non-cancer hazard index would be 100; still orders of magnitude above acceptable levels. The risk drivers remain much the same with somewhat different individual contributions.

2. Ecological Risk Summary

Based on the weight-of-evidence evaluation, 12 chemicals of potential ecological concern (COPECs) were identified across all assessment endpoints for terrestrial and aquatic receptor exposure scenarios. The following is a summary of the COPECs and potentially at- risk receptor groups: • Terrestrial Habitats

- Terrestrial Invertebrates—2,4'-dichlorodiphenyltrichloroethane, 4,4' -dichlorodiphenyldichloroethane (4,4' -DDD), 4,4'-dichlorodiphenyldichloroethane (4,4'-DDE), 4,4' -dichlorodiphenyltrichloroethane, and vanadium

- Terrestrial Invertebrates and Plants — gamma-BHC and benzene

• Aquatic Habitats - Benthic Invertebrates - 4,4'-DDD, 4,4'-DDE, and nickel - Aquatic Biota — aluminum, copper, iron, manganese - Semi-aquatic Omnivorous Mammals — aluminum

For terrestrial habitats, the COPECs exist primarily within the boundary of the former excavation area of the VBP. For aquatic habitats, the COPECs primarily occur within the intermittent stormwater drainage ditch due to exceedances of ambient water quahty criteria, although the contamination is probably attributable to background concentrations and multiple different source's, and not related to the VPB contamination. Therefore remediation of the intermittent stormwater drainage ditch will not be included as part of VBP remedy. A summary of ecological risks can be found in Table 3.

3. Basis for Taking Action

The EPA's Preferred Remedial Alternative identified in this Proposed Plan, or one of the other active measures considered in this Proposed Plan, is necessary to protect pubhc health or welfare or the environment from actual or threatened releases of hazardous substances into the environment.

V. REMEDIAL ACTION OBJECTIVES

Remedial Action Objectives (RAOs) for OUl (source material) were developed during the remedial alternatives evaluation and include the following:

• Reduce the spatial distribution of surficial burn debris not addressed during prior remedial action at the site.

• Reduce the mass and distribution of NAPL-impacted material to minimize contaminant flux to groundwater and prevent mobihzation under current and potential future hydrogeologic conditions.

• Minimize the migration of site-related contaminants from unsaturated and saturated media to the shallow unit, till unit, and lower unit.

• Prevent ingestion, inhalation, and direct contact of site-related contaminants in surface and subsurface soil to human and ecological receptors at concentrations that exceed unacceptable risk.

VI. SUMMARY OF REMEDIAL ALTERNATIVES

Five alternatives, including No Action, are under consideration for OUl at the VBP site. The EPA's preferred alternative is Alternative 4 - In Situ Thermal Treatment and Soil Cover.

Common elements of all Alternatives, excluding the No Action Alternative, are replacing the private water wells of the nine closest homes with the public water supply, short- and long-term groundwater monitoring activities at the site, placement of institutional controls at the site, and removal of or consolidation of nearby remnant burn pit ash/ debris under the cap/cover that will be placed over OUl. A comparison of the elements of each alternative can be found in Table 4, and cost estimates for each alternative can be found in Table 5. The following are the alternatives evaluated for the site:

• Alternative 1 - No Action. Alternative 1 provides a baseline for comparison to other alternatives, as required by the NCP. Alternative 1 does not include any further remedial action for soil. It does not include monitoring or institutional controls. The cost to implement Alternative 1 is $0. • Alternative 2 - Soil Containment and Capping. Alternative 2 would decrease the mobility of contaminants through a reduction in infiltration by use of a low-permeability soil cap, prevent direct contact to surface soils with the soil cap, and to complete infrastructure modifications to residential dwellings by connecting nine homes located south of the VBP to the municipal water supply. The main remedial components of Alternative 2 are containment, momtoring, and institutional controls.

Containment To prevent direct contact with contaminated soil as the site, a low-permeability soil cap would be installed. Additionally, the cap would reduce contaminant migration to groundwater by reducing the infiltration through the contaminated soil. Before cap placement, the remnant burn debris would be consolidated and graded within the subgrade fill from which the cap slopes will be constructed.

It is anticipated that the soil cap would consist of a 24-inch-thick low-permeability clay cap overlain by a 6-mch-thick topsod layer. The site would be graded to a minimum of 3 percent grades to promote positive drainage and minimize potential ponding over time. Slopes would be kept shaUower than a 10 percent grade to prevent potential slope stability and erosion issues over the long term. The cap would be seeded with native grasses and maintained after construction until satisfactory vegetation is established. Perimeter drainage swales would be incorporated to properly convey stormwater away from the capped area. The limits of the cap are shown in Figure 6 and would encompass the areas where contaminated soil and NAPL were identified in the RL The estimated area of the soil cap is 4.1 acres. The remnant debris (approximately 1,000 cubic yards) located southeast of the cap area would be consolidated under the cap and used as subgrade fill.

Monitoring Monitoring would include short- and/ or long-term monitoring with soil cap inspections. Mowing of the cap would be required at least three times yearly to aid in mamtaining the cap.

Institutional Controls Institutional controls would include deed restrictions, permitting, and infrastructure modifications. Following implementation of the remedial alternative, deed restrictions would be necessary to restrict land use, since source area soils will not be removed, to ensure source area soils are not brought to the surface from future excavation activities. Restrictions to groundwater use would also be necessary to prevent use of the contaminated ground water.

Municipal Water Connection Nine homes near the VBP would be connected to municipally- supplied water as a part of each alternative (except Alternative 1). Each existing residential well would be abandoned to eliminate the potential for future groundwater use. It is expected that the connection of service would start at the beginning of construction.

live Year Reviews Because this remedy would result in hazardous substances, pollutants, or contaminants remaining on-site above levels that allow for unlimited use and unrestricted exposure, a statutory review would be conducted within five years after initiation of remedial action to ensure that the remedy is, or would be, protective of human health and the environment.

The estimated cost to implement Alternative 2 is $3.1 million.

Alternative 3 - In Situ Stabilization and Soil Cover. Alternative 3 would incorporate amendments by methods of soil mixing to encapsulate the contaminated soils and decrease the mobility to groundwater with the use of sohdification, prevent direct contact to contaminated soils with a soil cover, and complete infrastructure modifications to residential dwellings by connecting the homes to the municipal water supply. The main remedial components of Alternative 3 are treatment, containment, monitoring, and institutional controls.

In Situ Solidification The sohdification of the soils reduces groundwater flow through fhe treated area by creating a solid mass with low permeability. The amendments (or reagents) may include bentonite, Portland cement, and cement kiln dust. Bentonite would be added to reduce the torque needed to rotate the augers during soil mixing. In addition, it would reduce the permeability of the mixed soil so the mass flux from the untreated residuals would be greatly reduced.

Portland cement or cement kiln dust may be added to encapsulate contaminated soil. Both amendments would be mixed with the VBP soil to solidify the soil between the ground surface down to the glacial till. Large-diameter (6 feet or greater) augers would be advanced to the target depth of approximately 33 feet bgs. Upon reaching the target depth, the amendments would be injected through the augers. The augers would be advanced and retracted through the soil interval several times to ensure complete mixing. The process would be repeated in overlapping columns until the entire area had been treated.

For the FS, the assumed area for in situ treatment is estimated to be 1.4 acres, and the total treatment depth is 33 feet based on the average depth to till. In addition, an appropriate study would be performed to determine the most suitable amendment and mix for achieving the RAOs. The auger diameter and spacing would be determined during the design. Figure 7 depicts where treatment would occur at the site.

Containment To prevent direct contact with contaminated soil at the site, a compacted sod cover would be installed. Before cover placement, the remnant burn debris would be consolidated and graded within the subgrade fill from which the cover slopes will be constructed.

It is anticipated that the soil cover would consist of a 12-mch-thick compacted soil cover overlain by a 6-inch-thick topsoil layer. The site would be graded to a minimum of 3 percent grades to promote positive drainage and minimize potential ponding over time. Slopes would be kept shallower than a 10 percent grade to prevent potential slope stability and erosion issues over the long term. The cover would be seeded with native grasses and maintained after construction until satisfactory vegetation is established. Perimeter drainage swales would be incorporated to properly convey stormwater away from the capped area. The limits of the cover are shown in Figure 7 and will encompass the area where elevated levels of impacts and the presence of NAPL were indicated in the RL The estimated area of the soil cover is 4.1 acres. The remnant burn pit ash/ debris (approximately 1,000 cubic yards) located southeast of the cover area would be consolidated under the cover and used as subgrade fill.

Monitoring

Monitoring would be the same in each alternative (except Alternative 1).

Institutional controls

Institutional controls would be the same in each alternative (except Alternative 1).

Municipal Water Connection Nine homes near the VBP would be connected to municipally-supplied water as a part of each alternative (except Alternative 1). Five Year Reviews Because this remedy would result in hazardous substances, pollutants, or contaminants remaining on-site above levels that allow for unlimited use and unrestricted exposure, a statutory review would be conducted within five years after initiation of remedial action to ensure that the remedy is, or would be, protective of human health and the environment. The estimated cost to implement Alternative 3 is $13.5 million.

• Alternative 4 - In Situ Thermal Treatment and Soil Cover. Alternative 4 would reduce and remove contaminants, decrease the mobility of contaminants to groundwater, prevent direct contact to contaminated soils with a soil cover, and connect residential dwellings to the municipal water supply. The main remedial components of Alternative 4 are treatment, containment, monitoring, and institutional controls.

In Situ Thermal Treatment Thermal treatment would be performed in situ to remove NAPL from subsurface soils to the till layer (subsurface soil and groundwater) and reduce the concentration of contaminants contained within the soil matrix in 1.4 acres. By reducing the mass of contaminants, including NAPL, the flux of contaminants to groundwater also would be reduced. Concurrent with heating operations, contaminants in liquid and vapor phase would be removed though vertical wells configured for multiphase extraction, and fluids extracted during subsurface heating would be captured aboveground and treated onsite. A variety of heating methods are commercially available; however, using electrical resistance heating was considered for cost estimating purposes. Should the EPA select Alternative 4 as the preferred remedy for the site, performance-based

16 procurement for in situ thermal treatment services using any commercially demonstrated form (or combinations thereof) of in situ heating would be pursued.

The area designated for treatment is 1.4 acres and would be completed at depth to the till layer. Figure 8 depicts where treatment would occur at the site.

Containment

Containment for Alternative 4 would be the same as for Alternative 2.

Monitoring

Monitoring would be the same in each alternative (except Alternative 1).

Institutional Controls

Institutional controls would be the same in each alternative (except Alternative 1).

Municipal Water Connection Nine homes near the VBP would be connected to municipally-supplied water as a part of each alternative (except Alternative 1). Five Year Reviews Because this remedy would result in hazardous substances, poUutants, or contaminants remaixung on-site above levels that allow for unlimited use and unrestricted exposure, a statutory review would be conducted within five years after initiation of remedial action to ensure that the remedy is, or would be, protective of human health and the environment. The estimated cost to implement Alternative 4 is $23.1 million. Alternative 5 - Hot Spot Excavation and Disposal. Alternative 5 would remove source soils and complete infrastructure modifications to residential dwellings by connecting the homes to the municipal water supply. The main remedial components of Alternative 5 are excavation, ex situ treatment, disposal, monitoring, and institutional controls.

Excavation Hot spot soils would be excavated along with remnant burn debris. The excavation would require steel sheetpiling, H-pdes for strut support, and substantial dewatering during excavation. The use of Level B personal protective equipment with supplied ah has been assumed because of the confined space nature of the excavation. Approximately 85,555 cubic yards of hot spot soil and 1,000 cubic yards of remnant burn pit ash/ debris removal were estimated. Struts and walers are anticipated to be used in conjunction with the sheet piles as adequate embedment depth is not available nor desired for use in excavation support.

Once sod has been removed, the excavation would be backfilled with clean soil. Sheet piles and the support system would be removed and decontaminated before leaving the site. The surface of the site would be graded to promote proper surface water management and restored with native grasses. Figure 9 depicts where hot spot excavation would occur at the site.

Ex Situ Treatment Excavated soils would require stabilization before disposal. Based on the removal volume estimate of 85,555 cubic yards, it has been assumed that a cement kiln dust and/ or fly ash would be required to stabilize the soils before transport. Soils would be stabilized such that free liquids would be removed. Water generated from dewatering would require treatment before disposal.

Disposal It is estimated that 85,555 cubic yards of soil would be generated for disposal at a Subtitle C landfill because of hazardous waste characteristics. Approximately 1,000 cubic yards of remnant burn pit ash/ debris would be disposed of at a subtitle D landfill because of its nonhazardous characteristics. Based on the high level of traffic on the local streets, a repair allowance of 12,500 square yards of damage has been included as a portion of this alternative.

Monitoring

Monitoring would be the same in each alternative (except Alternative 1).

Institutional Controls

Institutional controls would be the same in each alternative (except Alternative 1).

Municipal Water Connection Nine homes near the VBP would be connected to municipally-supplied water as a part of each alternative (except Alternative 1). Five Year Reviews Because this remedy will result in hazardous substances, pollutants, or contaminants remaining on-site above levels that allow for unlimited use and unrestricted exposure, a statutory review will be conducted within five years after initiation of remedial action to ensure that the remedy is, or will be, protective of human health and the environment. The estimated cost to implement Alternative 5 is $116.5 million.

Distinguishing features:

Alternative 1 is distinctive because there would be no action at the site.

Alternative 2 is the only alternative that would have an engineered clay cap, as opposed to a compacted soil cover that would cover the site and consolidated waste piles. Alternative 2 is also the only alternative, besides no action, that would not include any treatment of the waste at the site. Alternative 3 is the only alternative that would require mechanical mixing, requiring heavy equipment that could perform the stabihzing treatment at depth and over 1.4 acres. The contamination at the site would be stabilized in situ, with the contamination remaining at the site in a more stable state with reduced flux to the surrounding soils and groundwater. Alternative 4 is the only alternative that would require the installation of vertical wells for contaminant (vapor) capture during in situ treatment at the site, which would require significant up front installation. Alternative 4 would also require the most extensive air monitoring due to the volatilization of the contamination with the in situ thermal treatment.

Alternative 5 would require the most significant amount of infrastructure, including sheet puling around the entire site to the till surface and many large, high capacity pumps for dewatering in order to be able to excavate the hotspot areas down to the till layer. The abdity to implement this remedy is much more uncertain than the other alternatives. Alternative 5 would also require the most truck traffic of all the alternatives, due to waste being excavated and treated and disposed of off-site.

All alternatives, besides the No Action Alternative, will likely disrupt golf course clientele, and will require air monitoring to ensure the health and safety of site workers and the community.

VII. EVALUATION OF ALTERNATIVES

Nine criteria are used to evaluate the different remediation alternatives individually and against each other in order to select a remedy. This section of the Proposed Plan profiles the relative performance of each alternative against the nine criteria, noting how it compares to the other options under consideration. The nine evaluation criteria are described below. The "Detaded Analysis of Alternatives "can be found in the FFS. Overall Protectiveness of Human Health and the Environment determines whether an alternative eliminates, reduces, or controls threats to pubhc health and the environment through institutional controls, engineering controls, or treatment.

Compliance with ARARs evaluates whether the alternative meets applicable or relevant and appropriate requirements of Federal and State environmental statutes and regulations, or whether a waiver is justified. Long-term Effectiveness and Permanence considers the ability of an alternative to maintain protection of human health and the environment over time. Reduction of Toxicity, Mobility, or Volume of Contaminants through Treatment evaluates an alternative's use of treatment to reduce the harmful effects of principal contaminants, their ability to move in the environment, and the amount of contamination present. Short-term Effectiveness considers the length of time needed to implement an altemative and the risks the alternative poses to workers, residents, and the environment during implementation. Implementability considers the technical and administrative feasibility of implementing the alternative, including factors such as the relative availability of goods and services. Cost includes estimated capital and annual operation and maintenance costs, as well as present worth cost. Present worth cost is the total cost of an alternative over time in terms with today's dollar value. Cost estimates are expected to be accurate within a range of +50 and -30 percent. State/Support Agency Acceptance considers whether the State agrees with the EPA's analysis and recommendations, as described in the Proposed Plan. Community Acceptance considers whether the local community agrees with the EPA's analysis and preferred alternative. Comments received on the Proposed Plan are an important indicator of community acceptance.

Comparison of Alternatives to the Nine Criteria The comparative analysis of the remedial alternatives is presented below.

1. Overall Protection of Human Health and the Environment The RAOs proposed to address the source material are described in Section V. Alternative 1 (No Further Action) is not protective because it allows future direct contact of receptors to contaminated sods and does not prevent or minimize plume migration. Alternatives 2,3,4 and 5 are protective of human health and the envhonment because they prevent contact with the contaminated soil and decrease plume migration.

2. Compliance with Applicable or Relevant and Appropriate Requirements Alternative 1 (No Further Action) does not comply with ARARs. Alternatives 2,3,4 and 5 are expected to comply with ARARs. The primary ARARs to be met relate to the Migratory Bird Act, erosion controls during excavation, closure criteria, ah pollution emission requirements, and Michigan Part 201. The action to address groundwater contamination for OUl would be considered an interim action. A final groundwater remedy would be selected in a future ROD for OU2. Therefore, only those groundwater ARARs related to the interim groundwater action, and not the final groundwater remedy, were considered in this proposed plan. Specific ARARs are hsted in Table 5.

Discussion and Background on Michigan Part 201 In 1994, Michigan consolidated most of its environmental legislation to create one overall governing act. The Natural Resources and Environmental Protection Act (NREPA; Pubhc Act 451 ofl994) is intended to protect the envhonment and natural resources of the State; to codify, revise, consolidate, and classify laws related to the envhonment of the State; regulate lands, waters, and natural resources; and describe the duties of the government and pubhc in relation to the envhonment. NREPA is codified at Chapter 324 of the Michigan Compiled Laws, and is divided into several parts, each with its own purpose in identifying rules and regulations to carry out the duties of the act. The State legislature recognized that certain facdities containing hazardous substances which pose danger to pubhc health, safety, or welfare, or to the envhonment exist throughout the State. NREPA Part 201, Envhonmental

( 20 Remediation, provides the basis and guidelines for the cleanup of envhonmentally contaminated properties throughout the State. Part 201 also states that the liability of the response activities lies with the person(s) responsible for the contamination, whether it be a facility owned by the Federal government, State, local unit of government, commercial, or private entity. Along with identifying the proper measures that responsible parties should take to mitigate hazardous contamination, Part 201 and its implementing administrative rules identify generic criteria (chemical concentrations) for over 280 (the list is routinely updated based on new information) hazardous substances in the State of Michigan that are protective of pubhc health, safety, or welfare, and the envhonment for the reasonable and relevant exposure pathways. Part 201 requhes selection of the most stringent numerical criterion from among the pathways that are determined to be reasonable and relevant for exposure potential at a regulated facility. The reasonable and relevant pathways are determined based on site- specific evaluation of the eleven pathways (seven for soil, four for groundwater), and six other classifications (including: aesthetic criteria for groundwater, water solubility, sod

saturation concentration for soils [Csat], statewide background concentrations for sods, and two screening levels for groundwater [flammabihty/explosivity and acute inhalation] that are promulgated in administrative rules that implement Section 324.20120a (Cleanup Criteria) of the Michigan Compded Laws, as amended on December 30,2013.

Section 324.20120a of the Michigan Compiled Laws also establishes residential and non­ residential land use categories for which generic cleanup criteria are developed for each pathway or classification. The generic cleanup criteria for the specific pathways for both the residential and non-residential land use categories are based upon equations and assumptions which are also promulgated in adnunistrative rules that implement Section 324.20120a of the Michigan Compded Laws. As shown in the FFS Report, areas of the site have concentrations of contaminants greater than the Part 201 generic cleanup criteria. Table 2 shows the chemical-specific risks and hazards that were used in the development of remediation alternatives for the site.

3. Long-Term Effectiveness and Permanence The long-term effectiveness and permanence of the alternatives are evaluated in terms of the magnitude of residual risk and the adequacy and reliabdity of controls. The residual risk of Alternative 1 (No Further Action) would remain unchanged. The residual risk for Alternative 2 related to contaminant migration remains, since reduction in infiltration is the primary component of this alternative; however, there is no source removal. Alternatives 3 and 4 have a greater long-term effectiveness and permanence because the source material mobility (Alternatives 3 and 4) and volume (Alternative 4) are reduced. Alternative 5 has the greatest long-term effectiveness and permanence because the source material is removed.

The adequacy and rehabdity of Alternative 2 is the least effective. Alternative 3 is shghtly more protective than Alternative 2 because it solidifies the contaminated sod at depth. Alternative 4 is more effective than Alternative 3 because of contaminant reduction. Alternative 5 is the most effective because the source material is removed. The alternatives in order of least to greatest long-term effectiveness are: Alternative 1, Alternative 2, Alternative 3, Alternative 4, and Alternative 5.

4. Reduction of Toxicity, Mobility, and Volume through Treatment Alternatives 3 and 4 include an in situ treatment process. The volume, toxicity and mobility of contaminants in Alternative 4 are decreased through treatment, and mobdity is decreased for Alternative 3 through treatment/ solidification. The NCP preference for on- site treatment would be met by Alternatives 3 and 4. Alternative 2 would reduce plume mobdity, but a cap is not a treatment technology. Alternative 5 provides for solidification treatment before the material is disposed off-site, which reduces the contaminants mobility. The alternatives in order from least to greatest of reduction of toxicity, mobility, and volume through treatment are: Alternative 1, Alternative 2, Alternative 3/5, and Alternative 4.

5. Short-Term Effectiveness There are no additional risks associated with the actual construction and implementation of Alternative 1 because no remedial action would be taken. Except for Alternative 1, the remedial option with the greatest short-term protection of workers and the community is Alternative 2. This option has the least amount of truck traffic, shortest construction period, and does not require excavation or traffic disturbance. Dust generated during construction activities would be from clean sources. Alternatives 3,4 and 5 provide less short- term protection to the community than Alternatives 1 and 2 because of the short-term impact of the large number of trucks and heavy equipment required to implement the remedy.

Exposures are increased for Alternatives 3,4, and 5 due to the longer duration of construction and fugitive dust emissions. The exposures could be addressed through proper dust monitoring and suppression during construction, and appropriate erosion control measures. Alternative 5 would provide the least short-term protection to the community because of the impact of the temporary large number of trucks and heavy equipment required to implement the remedy and increase construction traffic. Alternative 5 would require the longest time to implement and requires operations that potentially could expose site workers and nearby human and ecological receptors to air-borne contaminants. In addition, recreational use of the golf course would be limited or prohibited during the longer implementation period for this alternative. The alternatives in order from least to greatest short-term protectiveness are: Alternative 5, Alternative 4, Alternative 3, Alternative 2, and Alternative 1.

6. Implementability Alternatives 3 and 5 have the greatest implementability chaUenges because of the large equipment needed and target depths for treatment and sohdification and instadation of sheet pdes for excavation (Alternative 5 only). Alternative 3 may include a bulking or volume increase in treated material because of the addition of stabilising agents to the subsurface which may result in mounding of excess material. If the excess material cannot be appropriately sloped for placement of the soil cap, it may be necessary to remove excess material and dispose of at an approved disposal facuity. Alternative 4 requhes mstalling and removing extensive subsurface infrastructure associated with the in situ heating and extraction equipment. Aside from the no action and containment-based alternative, however, implementabdity of Alternative 4 is the least challenging of the alternatives focused on source area treatment. The alternatives in order from least to greatest implementabdity are: Alternatives 5, Alternative 3, Alternative 4, Alternative 2, and Alternative 1.

7. Cost An overview of the cost analysis performed for this evaluation with the total costs hsted can be found in Table 6.

Alternative 1 (No Further Action) has the least present worth cost at $0. The lowest capital cost alternative, excluding the No Action Alternative, is Alternative 2 at $3,100,000 since it relies primardy on containment-only technologies.

Alternative 3 would incur the next highest costs because of mixing reagents and mobilization of large and specialized equipment, resulting in a cost of $13,500,000. Alternative 4 would be the next costly at $23,100,000 because it involves use of specialized equipment and proprietary technologies. The most expensive alternative is Alternative 5 with a cost of $116,500,000 because of the extensive costs for excavation stability and disposal of hazardous waste.

8. State and Community Acceptance These two criteria will be fully evaluated after the public comment period.

VIII. PREFERRED ALTERNATIVE

The EPA and MDEQ recommend that Alternative 4 be selected as the preferred alternative for OUl of the site. Alternative 4 will protect human health and the envhonment, comply with all ARARs, and satisfy the NCP preference for treatment of principal threat wastes. Alternative 4 is also more implementable than the other treatment options, and effective in the short and long-term.

Alternative 4 includes the following components:

• Thermal treatment performed in situ on 1.4 acres at depth to the till layer to remove NAPL and reduce the concentration of contaminants contained within the sod matrix. Through contaminant mass reduction and NAPL removal, the flux of contaminants to groundwater also would be reduced through thermal treatment operations. A variety of heating methods are commercially avadable; however, using electrical resistance heating was considered for cost-estimating purposes. The in situ thermal treatment (ISTT) system operation and performance would be based on a dimimshing returns strategy. Use of this strategy is common and weU documented to gauge ISTT system operation.

The dimimshing returns concept builds on multiple lines of evidence to demonstrate that the practical (and technical) capacity of a treatment system to remove COCs from contaminated media has been reached. Experience has shown that extending system operation beyond the point where COC recovery rates reach asymptotic conditions (a non-zero value) provides little benefit to improve overall treatment system performance. Therefore, given the high unit rate ($/ day) for ISTT system operation, the mass recovery rate as a function of time would serve as the primary line of evidence in determining when to terminate active treatment of the NAPL source area. This would allow the required flexibility to determine the optimal shutdown point while simultaneously balancing technology implementation costs and RAO attainment for NAPL at the VBP. Once it is determined from performance monitoring that: (1) treatment of the source area using ISTT has reached an asymptotic rate of COC recovery, (2) that additional input of subsurface energy wiU not increase COC mass removal rate, and (3) that extended operation of the ISTT system offers no further reduction in NAPL mobility and migration from the shallow outwash, the ISTT system would be shut down.

• Concurrent with heating operations, contaminants in liquid and vapor phase would be removed though vertical wells configured for multiphase extraction, and fluids extracted during subsurface heating would be captured aboveground and treated in a carbon scrubber or sinular treatment technology on-site. It is expected that the ISTT would treat COCs in the sods and groundwater at OUl, in addition to the NAPL. The only emissions released to the atmosphere from the treatment would be water vapor.

• To prevent direct contact with remaining contaminated sod at the site, a compacted sod cover would be installed. The limits of the cover are shown in Figure 7 and will encompass the area where elevated levels of impacts and the presence of NAPL were indicated. The estimated area of the sod cover is 4.1 acres. The remnant burn pit ash/ debris (approximately 1,000 cubic yards) located southeast of the cover area would be consolidated under the cover and used as subgrade fill. The cover would be seeded with native grasses and maintained after construction until satisfactory vegetation is established.

• Perimeter drainage swales would be incorporated to properly convey stormwater away from the capped area.

• Short- and/ or long-term groundwater monitoring would be completed by conducting sod cap inspections. Mowing of the cap would be required at least three times yearly to aid in mamtaining the cap.

• Institutional controls including deed restrictions, pernhtting, and infrastructure modifications would be required. Following implementation of the remedial alternative, deed restrictions would be necessary to restrict land use, since source area sods will not be removed, to ensure source area sods are not brought to the surface from future excavation activities. Restrictions on groundwater use would also be placed.

• Nine homes near the VBP would be connected to municipaUy-supphed water. Each existing residential well will be abandoned to eliminate the potential for future groundwater use. It is expected that the connection of service would start at the beginning of construction. • The estimated cost for Alternative 4 is $23.1 million. A detaded cost estimate for Alternative 4 can be found in Table 7.

Alternatives 2,3,4 and 5, are aU protective of human health and the environment and meet all ARARs, but Alternative 4 is the best balance of the nine criteria compared to the other alternatives. Alternative 4 also satisfies the preference for treatment of principal threat wastes by using in situ thermal treatment to reduce the volume, toxicity, and mobdity of the NAPL at the Site.

Alternative 4 is preferred by the EPA because the treatment technology has been proven to be effective at similar sites and is a cost-effective technology at this Site. Alternative 4 also is more implementable than the other Alternatives that employ permanent remediation techniques and there is less hkelihood of having to change the remedy due to implementabdity issues.

If new information is discovered which requhes a fundamental reevaluation of the site remedy and a Record of Decision Amendment is required, the EPA will ensure the pubhc is informed and the pubhc participation process pursuant to the EPA guidance is implemented. A Contingency Plan will also be developed and discussed with the pubhc to ensure the community, including nearby residents, are notified if any site emergencies develop.

Based on information currently available, the EPA beheves the Preferred Alternative meets the threshold criteria and provides the best balance of tradeoffs among the other alternatives with respect to the balancing and modifying criteria. The EPA expects the Preferred Alternative to satisfy the following statutory requhements of CERCLA Section 121(b), 42 U.S.C. § 9621(b): (1) be protective of human health and the envhonment; (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.

The groundwater action in the Preferred Alternative for this OU is an Interim Action, and a final groundwater remedy will be selected in a future ROD for OU2. Therefore, only those groundwater ARARs related to the interim groundwater action, and not the final groundwater remedy, were considered in this proposed plan.

IX. COMMUNITY INVOLVEMENT The EPA is committed to keeping the City of St. Louis and the community informed as to the progress of the site cleanup. The EPA or its representative will continue to attend the Pine River Superfund Citizen Task Force meetings to ensure the community is informed as to the progress of the site cleanup. In addition, the EPA will work with the MDEQ and community on the development of an internet site that will provide the City of St. Louis and community a way to stay informed as to the dady site activities.

FIGURES 4

4* INK'***;

CH2BSHILL * • m t i r i • i

•IE

Legend

2007 MDEQ Rl Groundwater Sampling Result from Temporary Welt Monitoring Well Groundwater to Surface Water Interface (GSI) Transect Boring Soil Boring Benzene concentrations in groundwater exceed one or more applicable MDEQ ^Part 201 Generic Residential Criteria or USEPA MCL in Shallow Outwash Unit Benzene concentrations in groundwater exceed one or more applicable MDEQ Part 201 Generic Residential Criteria or USEPA MCL in Perched Water Lens

I Velsicol Trust Burn Pit Area Approximate Former Burn PitArea " 1952 Excavation Limits

NOTE: Purple and red text represent benzene concentrations in groundwater from the Perched water Lens and Shallow Outwash Unit, respectively. Text contained In boxes with purple and red borders indicate areas where MDEQ Part 201 criteria are exceeded in the Perched Water Lens and Shallow Outwash Unit, respectively.

MDEQ Part 201 Generic Residential Criteria:

Drinking water = 5 ug/L Groundwater surface water/interface = 200 ug/L Groundwater volatilization to indoor air inhalation = 5,600 pg/L Groundwater contact = 11,000 ug/L

Benzene Distribution in Perched Water Lens and 100 200 Feet Shallow Outwash Unit, July-August 2012 Velsicol Bum Prt _l I Superfund Site - Proposed Plan St. Louis, Michigan CH2NIH1LL. 1^ I ( I I

• • • ,.rater Sampling Result from Temporary Well Monitoring Well Groundwater to Surface Water Interface (GSI) Transect Boring Soil Boring 1,2-dichloroethane concentrations in groundwater exceed one or more applicable MDEQPart 201 "Generic Residential Criteria orUSEPA MCL in Shallow Outwash Unit 1,2-dichloroethane concentrations in groundwater exceed one or more applicable MDEQ Part 201 ^Generic Residential Criteria or USEPA MCL in Perched Water Lens t- Velsicol Trust Bum Pit Area Approximate Former Burn PitArea 11982 Excavation Limits

NOTE: Green and blue text represent 1,2-dichloroethane concentrations in groundwater from the Perched water Lens and Shallow Outwash Unit respectively. Text contained in boxes with green and blue borders indicate areas where MDEQ Part 201 criteria are exceeded in the Perched Water Lens and Shallow Outwash Unit, respectively.

MDEQ Part 201 Generic Residential Criteria:

Drinking water = 5 pg/L Groundwater surface water/interface - 360 pg/L Groundwater volatilization to indoor air inhalation ~ 9,600 pg/L Groundwater contact = 19,000 pg/L

USEPA MCL

Figure 3 1,2-Dichloroethane Distribution in Perched Water Lens and 100 200 Feet Shallow Outwash Unit, July-August 2012 Velsicol Bum Pit Superfund Site - Proposed Plan __l I Sc. Louis, Michigan CMZfUfKJLt. ,uis Figure S.<27?2Dt3 ig Well rater to Surface Water (GSI) Transect Boring le Interface Probe (MIP) ing

Trust Burn Pit Area late Former Burn Prt Area ;avation Limits

Figure 4 Aerial Extent of NAPL identified in MIP Borings, Soil Borings and Monitoring Wells Velsicol Burn Pit Superfund Site - Proposed Plan Figure 5 Conceptual Model for the former Velsicol Burn Pit

RECEPTORS ;; liilollll !;pIiiAll: ^l^TE^RfiiRY'H ^.SECOND--: ct to CO PRIMARY TERTIARY EXPOSURE EXPOSURE w^vARYai^ • CO o £ Q: SOURCE •:SOURGEw; llllililll; PATHWAY Ui ^SOURCE : • lliielii;;:: _i si §1 o O H z 5 o 5 * > <

FORMER INGESTION • • • • • VELSICOL DERMAL o BURN PIT • • • • SOILS INHALATION • • • • •

VAPOR INDOOR INHALATION MIGRATION AIR • •

:THETIDAI! ^•TFUTllii's isBU RllilTl !i;!§i!lli:

VELSICOL FORMER INGESTION PLANT v VELSICOL GROUND­ * * LEKDHINS iDRINKlN.G: DERMAL WASTE BURN PIT WATER K|#[T£R#: * * MATER-; SOILS INHALATION * * IALS lEXlSTMGl

DISCHARGE

KEY 1 +J RUN OFF SURFACE SURFACE INGESTION o o COMPLETE, OR POTENTIALLY WATER DERMAL o o COMPLETE, EXPOSURE llwlfiRl: PATHWAY COMPLETE, OR POTENTIALLY PRECIPI­ INGESTION o o SEDIMENT SEDIMENT COMPLETE, BUT MINOR TATION DERMAL o o EXPOSURE PATHWAY KF POTENTIALLY COMPLETE IN THE FUTURE, BUT A LOCAL BIOACCUM ORDINANCE PROHIBITING FISH INGESTION o GROUNDWATER USE AS -ULATION DRINKING WATER IS ANTICIPATED. .egend

Cap Limits 1 * (400'X 450'- 180,000 ft2)

I • Velsicol Trust Burn Pit Area Approximate Former Burn Pit Area B 1982 Excavation Limits

NAPL Source Area

Figure 6 Alternative 2 - Soil Containment/Capping 100 Feet Velsicol Burn Pit Superfund Site - Proposed Plan _! St. Louis, Michigan

-CH2IWHIU. sFigareSAflomESve y - * J - 1

!

3S. •

fsffm HI illiiiii Legend

In-Sitaj Soil Stabilization Limits ^^^(200' x 350' x 33' - 85,555 yd3) Surface Cover ••• (4O0'x450'-180,0OOfP) • -m • Velsicol Trust Burn Pit Area Approximate Former Burn Pit Area 1 1982 Excavation Limits

NAPL Source Area F - 4J» iff ™

Figure 7 Alternative 3 - In-Situ Soil Stablization and Soil Cover 0 50 100 Feet Velsicol Burn Pit Superfund Site - Proposed Plan I I I St Louis, Michigan ^{200' x 350' x 33' - 85,555 yd3) Surface Cover 1 B " (400' x 450' - 180,000 ft2)

I 1:9 'Velsicol Trust Burn PftArea

Approximate Former Burn Pit Area 1982 Excavation Limits 22NAP L Source Area

Figure 8 Alternative 4 - In-Situ Thermal Treatment and Soil Cover 0 50 100 Feet Velsicol Burn Pit Superfund Site - Proposed Plan 1 l I Si. Louis, Michigan iBi ilii m

Hot Spot Removal/Treatment Area ^{200' X 350' x 33 - 85,555 yd3) Surface Soil Removal to 2' and 1 Backfill/Grade with Clean Soil

Figure 9 Alternative 5 - Excavation and Disposal Velsicol Burn Pit Superfund Site - Proposed Plan St. Louis, Michigan

•d Feasibility StedvlFeb £314\St Lo-jIe Figure SA! 02/05,7014 r

TABLES Table 1. List of Contaminants of Concern for Velsicol Burn Pit Site

Velsicol Burn Pit - Chemicals of Concern

(Chemicals Exceeding at Least One Part 201 Applicable Cleanup Criteria)

Groundwater Soil

Volatile Organic Compounds Volatile Organic Compounds 1,2-Dichloroethane Acetone Benzene 1,1-Dichloroethane Carbon Tetrachloride Chlorobenzene Benzene Chlorobenzene l,2-Dibromo-3-chloropropane Chloroform 1,2 DibromO'3-chloropropane 1,2-Dichloroethane Toluene Methylene Chloride Metals Trichloroethyiene Vinyl Chloride Aluminum Arsenic Metals Cobalt Aluminum Arsenic Iron Barium Chromium, tot Magnesium Iron Lead Manganese Magnesium Manganese Mercury Mercury Nickel Selenium Selenium Sodium Vanadium Zinc Table 2 Summary of Risk and Hazard Estimates

» • ••• Ato? "5«Ti

Current/ Adolescents 1,2-DCA-47.8% 1,2-DCA-68.2% Future Recreational 75 24 6.E-07 6.E-03 + Adults Arsenic - 30.0% Arsenic - 18.5% Users (Golfers)

Adolescents Surface Soil 1,2-DCA-47.8% 1,2-DCA-68.4% Site Visitors 15 24 l.E-07 l.E-03 + Adults Arsenic - 29.8% Arsenic - 18.7% (Trespassers) Soil Outdoor Workers 1,2-DCA-43.6% 1,2-DCA - 65.7% Adults 125 25 l.E-06 l.E-02 (Grounds Keepers) Arsenic-31.9% Arsenic - 20.8%

l,2-DB-3-CP - 73.2% PBB - 55.3% Excavation Workers Adults Soil 0-10 ft bgs l.E-06 l.E-01 PBB - 23.3% 1.2-DB-3-CP -40.9% Future Sofl Soil 0-10 ft bgs l.E-03 0.1% 4.E+00 0.04%

Tapwater 9.6E-01 98.: 8.E+03 94.5% Ground Water Indoor Air 6.E-02 1.7% 5.E+02 5.4% (Vapor Intrusion) Integrated l,2-DB-3-CP - 79.9% 1,2-DCA - 50.1% Residents 350 30 Receptor Totals - Child/Adult 1,2-DCA - 12.4% E2-DB-3-CP - 24.5% All Media and 9.6E-01 9.E+03 Benzene - 4.9% Benzene - 18.6% Exposure Routes: Arsenic - 2.2%. Arsenic - 4.3%

Receptor Totals for Benzene - 39.0% Benzene - 47.9% Soil Contact and 6.E-02 l,2-DB-3-CP - 30.0% 5.E+02 1,2-DCA-46.2% Vapor Intrusion only: 1,2-DCA-29.3% 1.2-DB-3-CP - 2.9%

Soil Soil 0-10 ft bgs 2.E-04 0.91% 7.E-01 0.03%

Tapwater l.E-01 96.3% 2.E+03 94.60% Ground Water Indoor Air l.E-02 l.E+02 5.30% (Vapor Intrusion)

Indoor Workers Adult 250 25 l,2-DB-3-CP - 62.4% 1,2-DCA-49.3% Receptor Totals - 1,2-DCA-26.6% I,2-DB-3-CP-24.5% All Media and 3.E-01 2.E+03 Benzene - 11.3% Benzene - 19.2% Exposure Routes: Arsenic - 4.9% Arsenic - 4.2%

Receptor Totals for Benzene - 47.8% Benzene -47.9% Soil Contact and l.E-02 L2-DB-3-CP - 14.4? l.E+02 1,2-DCA-46.2% Vapor Intrusion only: 1,2-DCA - 35.9% l,2-DB-3-CP-2.9%

l,2-DB-3-CP: l,2-Dibromo-3-chloropropane; 1,2-DCA l,2-Dicbloroethane;PBB: Polybromobiphenyl.

05: 230400270201TT0 CHI1795 Agency Draft VBPBHHRA.docx-3/29/2013 TABLE 3 COPECs and Potentially At-risk Receptor Groups

At-Risk Receptors Habitat

Upper Lower Trophic COPEC Trophic (Food Web) Terrestrial Aquatic Spatial Extent

Northwest corner of the former excavation limits of the VBP (BA-D7, 2,4-DDT BA-10, BA-D6, and BA-E6) and in the southeast corner of the VBP boundary and immediately offsite (BA-F5, BA-F4, and BA-G4)

Northwest corner of the former excavation limits of the VBP (BA-D7, 4,4-DDD SI, BI BA-10, BA-D6, and BA-E6), in the southeast corner ofthe VBP boundary and immediately offsite (BA-F5, BA-F4, and BA-G4), and within the drainage ditch (PH4-SED-01A, PH4-SED-01B, PH4-SED-02, 4,4-DDE SI, BI and PH4-SED-03)

Northwest corner ofthe former excavation limits ofthe VBP (BA-D7, 4,4-DDT SI BA-10, BA-D6, and BA-E6) and in the southeast comer of the VBP boundary and immediately offsite (BA-F5, BA-F4, and BA-G4) gamma-BHC TP/SI

Aluminum AB Raccoon X Length of drainage ditch focused at PH4-SW-03

Benzene TP/SI BA-10

Copper AB PH4-SW-03

Iron AB PH4-SW-02 and PH4-SW-03

AB PH4-SW-01 and PH4-SW-03 Manganese

Within the drainage ditch (PH4-SED-01A, PH4-SED-01B, PH4-SED-02, BI Nickel and PH4-SED-03)

Vanadium SI BA-B5

SI = soil invertebrates BI = benthic invertebrates TP = terrestrial plants AB = aquatic biota TABLE 4 Detailed Evaluation of Remedial Alternatives Velsicol Burn Pit Superfund Site, St. Louis, Michigan Alternative Description: Alternative 1—No Further Alternative 2—Soil Containment Alternative 3—In Situ Soil Alternative 4—In Situ Thermal Alternative 5— Hot Spot Criterion Action and Capping Stabilization and Soil Cover Treatment and Soil Cover Excavation and Disposal

1. Overall Protection of • RAOs would not be met Permeability to increase • Direct contact removed. • Direct contact removed. • Direct contact removed. Human Health and the because migration of through the cap overtime. Prevent plume migration. • Prevent plume migration. • Prevent plume migration. Environment contaminants would • Direct contact removed. continue. • Source removed. • Prevent plume migration. • Direct contact not removed.

2. Compliance with ARARs • ARARs not met because no • All ARARs are met. • All ARARs are met. • All ARARs are met. • All ARARs are met. remedial action is taken to • • • address unacceptable risk. Requires proper protection Requires proper Requires proper Requires proper protection for erosion control, air protection for erosion protection for erosion for erosion control, air emissions, and dust control. control, air emissions, and control, air emissions, and emissions, and dust dust control. dust control. control. • Proper trench excavation. • Transportation of hazardous waste to be managed.

3. Long-term Effectiveness and Permanence

(a) Magnitude of residual • Risk would remain constant • Exposure to contaminants in • Exposure to • Reduction in source soils. • Exposure to contaminants risks over decades given the very soil would be prevented contaminants in soil • Exposure to eliminated by removing slow or lack of degradation through capping. would be prevented contaminants in soil the source and impacts. of contaminants. through covering. No source removal but would be prevented containment. • No source removal but through covering. containment. • Prevents plume migration. • Prevents plume migration through solidification.

(b) Adequacy and " Not applicable. Containment and • Containment and • Containment and • Contaminant removed. Soil reliability of controls institutional controls are institutional controls are institutional controls are controls no longer adequate and reliable in adequate and reliable in adequate and reliable in required. preventing direct contact preventing direct contact preventing direct contact and migration but will and migration but will and migration but will require maintenance and require maintenance and require maintenance and monitoring. monitoring. monitoring. TABLE 4 Detailed Evaluation of Remedial Alternatives Velsicol Burn Pit Superfund Site, St. Louis, Michigan Alternative Description: Alternative 1—No Further Alternative 2—Soil Containment Alternative 3—In Situ Soil Alternative 4—In Situ Thermal Alternative 5— Hot Spot Criterion Action and Capping Stabilization and Soil Cover Treatment and Soil Cover Excavation and Disposal

4. Reduction of Toxicity, Mobility, or Volume Through Treatment

(a) Treatment process • No treatment processes • No treatment processes • Solidification. • Thermal treatment. • No treatment processes used used. used. used.

(b) Degree and quantity • None. • Mobility reduced • No reduction in volume. • Partial removal. » Mobility eliminated with of TMV reduction significantly. Reduction in mobility. M Reduction in mobility. source removal.

(c) Irreversibility of TMV • Not applicable. • Not applicable. • Solidified mass Irreversible. • Irreversible. reduction degradable over time.

(d) Type and quantity of • Not applicable. " Not applicable. Solidification. • Thermal treatment. • 85,555 cubic yards of soil treatment residuals 85,555 cubic yards of • 85,555 cubic yards of soil stabilized before disposal. impacted soil solidified. treated.

(e) Statutory preference • Preference not met • Preference not met because • Preference met. Preference met. • Preference met. for treatment as a because no treatment no treatment included. principal element included. 5. Short-term Effectiveness

(a) Protection of workers No remedial construction, Moderate risks to workers Increased risk over Increased risk over High risks to workers during remedial so no risks to workers. during construction due to Alternatives 2 because of Alternative 2 because of during construction due to action pressurized equipment and the additional equipment the additional equipment large excavation, exposure lines. Proper health and required and the longer required and the longer to soil and water safety procedures must be construction duration. construction duration. management. Proper followed during Moderate risks to workers Low to moderate risks to health and safety construction. during construction workers during procedures must be because of large construction because of followed during equipment. Proper health drill rigs. Proper health construction. and safety procedures must and safety procedures be followed during must be followed during construction. Increased risk construction. over Alternative 2 because Increased risk to truckers ofthe duration and from accidents from excavation depth. increases in total trips Increased risk to truckers made. from accidents from increases in total trips made. TABLE 4 Detailed Evaluation of Remedial Alternatives Velsicol Burn Pit Superfund Site, St. Louis, Michigan Alternative Description: Alternative 1—No Further Alternative 2—Soil Containment Alternative 3—In Situ Soil Alternative 4—In Situ Thermal Alternative 5— Hot Spot Criterion Action and Capping Stabilization and Soil Cover Treatment and Soil Cover Excavation and Disposal

Protection of • No remedial construction, • There are limited risks to the • Increased risks to the • Increased risks to the • Increased risks to the community during so no short-term risks to community during community during community during community during remedial action community. construction, because of construction due to the construction due to the construction due to the limited traffic access increased transport of increased transport of increased transport of required. materials on and off the materials on and off the materials on and off the site and duration of site and duration of site and long duration of construction. construction. construction. Environmental • No remedial construction, • Erosion controls. • Erosion controls. - Erosion controls. • Erosion controls. impacts of remedial so no environmental • Environmental impacts will • Emissions of • Emissions of " Environmental impacts will action impacts from remedial likely be limited to emissions contaminants in dust may contaminants in dust may likely be limited to action. of contaminants in dust, occur, although minimal occur, although minimal emissions of contaminants although minimal dust would dust would be anticipated dust would be anticipated in dust, although minimal be anticipated since the soils since the soils are since the soils are dust would be anticipated are saturated. The impacts saturated. The impacts saturated. The impacts since the soils are can be controlled through can be controlled through can be controlled through saturated. The impacts can use of dust suppressants as use of dust suppressants use of dust suppressants be controlled through use necessary. as necessary. as necessary. of dust suppressants as • Environmental impacts • Environmental impacts necessary. will include increased will include increased " High levels of diesel greenhouse gas emissions greenhouse gas emissions vehicles for excavation. due to the increase in the due to the increase in the loading and transportation number of truckloads and number of truckloads and for disposal. miles required. miles required. • Additional dust potential • Handling of fluids to be with reagents used for potentially generated mixing. during drilling that require treatment. Time until RAOs are • Not met. • Evaluation of long-term • Evaluation of long-term • Evaluation of long-term • Immediately after achieved monitoring results would be monitoring results would monitoring results would construction. required after construction be required after be required after to evaluate if RAOs were construction to evaluate if construction to evaluate if achieved. RAOs were achieved. RAOs were achieved. TABLE 4 Detailed Evaluation of Remedial Alternatives Velsicol Burn Pit Superfund Site, St. Louis, Michigan Alternative Description: Alternative 1—No Further Alternative 2—Soil Containment Alternative 3—In Situ Soil Alternative 4—In Situ Thermal Alternative 5— Hot Spot Criterion Action and Capping Stabilization and Soil Cover Treatment and Soil Cover Excavation and Disposal

6. Implement ability (a) Technical feasibility • No impediments. • Borrow source selection for The main technical • The main technical • Excavation stability of low-permeability clay. challenge is depth and challenge is accuracy and significant concern. completeness of soil success of treatment. • Water management during mixing. construction

(b) Administrative • No impediments. • Requires institutional • Requires institutional • Requires institutional • Health and safety risks feasibility controls and monitoring. controls and monitoring. controls and monitoring. associated with Level B personal protective equipment and excavation safety.

(c) Availability of services • None needed. • Services and materials are • Services and materials are • Services and materials are " Services and materials are and materials available. available. available. generally available. • Sheet pile usage extensive. 7. Total Cost Direct Capital Cost • $0 $2,400,000 • $12,800,000 • $22,400,000 $116,500,000 Initial Operation and • SO $50,777 • $50,077 • $50,077 • $0 Maintenance Cost

Total Periodic Cost • $0 $90,000 • $90,000 • $90,000 $90,000 Total Present Value • $0 $3,100,000 • $13,500,000 • $23,100,000 $116,500,000 TABLE 5-1 Federal - Potentially Applicable or Relevant and Appropriate Requirements and To-Be-Considered Standards Velsicol Burn Pit Superfund Site, St. Louis, Michigan

Regulation Requirement ARAR Status Analysis

Federal Chemical-specific ARARs

No federal chemical specific ARARs were identified for OUl

Federal Location-specific ARARs

16 United States Code 703 - Migratory Bird Protects almost all species of native birds in the Applicable Applicable if migratory birds, or their nests or eggs, are Treaty Act United States from unregulated taking. identified at the site at any time. Operations will not destroy the birds, nests, or eggs unless approval is obtained.

Federal Action-specific ARARs

40 CFR 265, Subparts I and J - Use and Subpart I sets operating and performance Applicable Applicable if hazardous waste is generated and Management of Containers and Tank standards for storage of hazardous waste in managed in containers or tanks onsite prior to offsite Systems containers under generator accumulation rules. disposal.

Federal To-Be-Considered Regulations

CERCLA Guidance on Land Use in the Establishes appropriate considerations for To Be Considered Provides guidance to EPA in selecting land use for CERCLA Remedy Selection Process defining future land use. remedy selection purposes. TABLE 5-2 State of Michigan - Potentially Applicable or Relevant and Appropriate Requirements and To-Be-Considered Standards Velsicol Burn Pit Superfund Site, St. Louis, Michigan

Regulation Requirement ARAR Status Analysis

State of Michigan Chemical-specific ARARs

No State of Michigan chemical specific ARARs were identified for OUl

State of Michigan Location-specific ARARs

Part 365, Endangered Species Protection, of Establishes requirements for conservation, Relevant and Relevant and appropriate for actions that are likely to the Natural Resources and Environmental management, enhancement, and protection of Appropriate jeopardize fish, wildlife, or plant species or destroy or Protection Act, 1994 PA 451, as amended species either endangered or threatened with adversely modify critical habitat. Would not be (NREPA), and extinction considered applicable unless Federal endangered species law is less stringent.

Michigan Compiled Laws (MCL) 324.36501- 36507), and

Michigan Administrative Code (MAC): R 299.1021-1028

Part 411, Protection and Preservation of Fish, Regulates the protection and preservation offish, Relevant and May be applied to site remediation to protect and Game, and Birds, NREPA and game, and birds Appropriate preserve fish, game, and birds; substantive requirements of Orders issued by the Natural Resources Commission ofthe Department of Natural MCL 324.41101-41105 Resources would apply to the taking or killing of regulated fish, game, or birds.

Part 413, Invasive Species, NREPA and Lists nonnative species that are prohibited or Applicable For any proposed or required planting, the restricted I Michigan; provides authority and requirements of Part 413 will apply to the selection or procedures for State Natural Resources introduction of plant species. MCL 324.41301-324.41325). Commission to add or delete from the list. Provides for a permit for introduction of genetically engineered organisms. Provides penalties for violations.

State of Michigan Action-specific ARARs

MAC R 299.9302 - Hazardous Waste Generators of any waste must determine, either Applicable Applicable to all wastes managed onsite. Used for Determination through knowledge or testing, whether the waste characterizing and identifying hazardous wastes and is a hazardous waste regulated under these rules. determining appropriate disposal options. Determining whether wastes qualify as hazardous will often establish the applicability of other regulations.

MAC R 299.9305 - Pre-transport Establishes minimum standards for preparing Applicable Applicable if hazardous waste is generated and Requirements hazardous waste for shipment offsite. managed onsite prior to offsite shipment and disposal.

MAC R 299.9306 - Accumulation Time Establishes minimum standards for managing Applicable Applicable if hazardous waste is generated and hazardous wastes onsite. The requirements of managed onsite prior to offsite shipment and disposal. 40 CFR 265 are incorporated by reference. TABLE 5-2 State of Michigan - Potentially Applicable or Relevant and Appropriate Requirements and To-Be-Considered Standards Velsicol Burn Pit Superfund Site, St Louis, Michigan

Regulation Requirement ARAR Status Analysis

Part 31, Water Resources Protection, NREPA, Sets requirements for onsite discharges of Relevant and Potential spills from the remedial action may result in and industrial wastewater as well as industrial and Appropriate or the discharging of remediated and/or unremediated construction stormwater to both surface waters Applicable contaminated groundwater into waters ofthe State, and groundwater ofthe State. Prohibits direct or i.e., groundwater, surface water, or any other water MCL 324,324.3104-3117 et seq, and indirect discharge to ground or surface waters of course; if so, the substantive requirements would be the state that are or may become injurious to the relevant and appropriate. Applicable only if Part 4: Water Quality Standards, and environment or public health. Defines effluent wastewater or stormwater that has not contacted guidelines based on actual water quality, contaminated media requires discharge during remedial Part 8: Water Quality Based Effluent Limits receiving stream properties, and other operations at the site. The current remedial design appropriate water quality criteria. Provides includes containerization and offsite disposal of all criteria and standards for the National Pollutant water that contacts contaminated media during the Discharge Elimination System (NPDES) and execution of the remedial action. The alternatives do effluent standards for toxic pollutants. This is the not include extracting, treating, or discharging implementing statute for the federally delegated contaminated groundwater or discharging to surface NPDES program. water.

Cites specific requirements for the discharge of bioaccumulative chemicals. Prevents concentrations in surface water of taste and odor producing substances. Prevents acutely and chronically toxic substances from entering surface water based on LC50 toxicity criteria. Prevents degradation of water quality. Restricts levels of turbidity, color, oil films, floating solids, foams, settling and suspended solids and deposits.

Part 91, Soil Erosion and Sediment Control, Establishes requirements for the control of Applicable or Relevant Relevant and appropriate to the excavation of highly NREPA and erosion and sedimentation during earth-change and Appropriate contaminated soil. Applicable if more than 1 acre will operations. be disturbed or for any disturbance within 500 feet of the water's edge of a lake or stream. Onsite CERCLA MAC R 323.1709 - Erosion and Sediment actions are exempt from administrative requirements Control such as administrative reviews and permitting; however, the substantive requirements must be met.

Part 55, Air Pollution Control, NREPA and Establishes rules for prohibiting the emission of Relevant and Relevant and appropriate for remedial actions where fugitive dust from certain activities in quantities Appropriate contaminated soil may become airborne and would which cause injurious effects to human health, MAC R 336.1372(8)(b) - Control of Fugitive generate fugitive dust and air emissions at trigger animal life, plant life, or significant economic Dust levels. Onsite CERCLA actions are exempt from value, and/or property. Establishes common administrative requirements such as administrative measures to mitigate the generation of fugitive reviews and permitting; however, for certain remedial dust during small-construction work. alternatives, air emissions must comply with substantive requirements and monitoring may be required. TABLE 5-2 State of Michigan - Potentially Applicable or Relevant and Appropriate Requirements and To-Be-Considered Standards Velsicol Burn Pit Superfund Site, St. Louis, Michigan

Regulation Requirement ARAR Status Analysis

Part 111 - Hazardous Waste Management, Establishes requirements for hazardous waste Relevant and Relevant and appropriate - response activities may NREPA), and generators, transporters, and Appropriate. generate waste that may be classified as hazardous treatment/storage/disposai facilities. Includes waste from former plant site. Used for characterizing requirements for use of a manifest system (R and identifying hazardous wastes and determining MCL 324.11101-11153, and 299.9608-9609) to track the type and quantity of appropriate disposal options. hazardous waste received by or shipped from a Part 111 Rules - MAC R 299.9101-11107 facility.

Part 121, Liquid Industrial Wastes, NREPA Regulates liquid industrial waste generators, Relevant and Remedial action may require the onsite storage and and transporters and designated facilities. Appropriate transportation of liquid industrial wastes. Relevant and MCL 324.12101-12118 Transporters are required to be registered in appropriate for the on site management of liquid accordance with the hazardous materials industrial wastes. transportation act. Liquid industrial waste is defined as "any liquid waste, other than unpolluted water."

Part 201, Environmental Remediation, NREPA Part 201 provides for the identification, risk Applicable Establishes screening levels and generic cleanup and assessment, evaluation, remediation, and long criteria for sites of environmental contamination term management of contaminated sites within based on current and future land use. Site-specific the State of Michigan. Part 201 provides that cleanup criteria can be developed if such criteria, in MCL 324.20101-20142 etseq., and response actions shall be protective of human comparison to generic criteria, better reflect best health, safety, welfare, and the environment of available information concerning the toxicity or MAC: R 299.1-299.50. the State and identifies risk levels to be used in exposure risk posed by the hazardous substance or the development of those response actions at other factors. Applicable to cleanup of releases of MCL 324.20120a and 324.20120b. hazardous substances in concentrations that constitute a facility as the term is defined in the NREPA.

Part 301 - Inland Lakes and Streams, NREPA Lists operations that are prohibited and Potentially Relevant and Currently not an ARAR. The selected alternative does and conditions for operations impacting lakes and Appropriate not involve placement of structures, fill, or dredging in streams, including mitigation. the river channel, streambed or intermittent drainage ditch. If such actions are taken the substantive MCL 324.30101-30113 requirements of these regulations may be potentially Relevant and Appropriate.

Part 303, Wetland Protection, NREPA and Provides for protection and conservation of Potentially Relevant and Available data does not support the presence of wetlands, including establishing rules regarding Appropriate wetlands. The nearby drainage ditch is not expected wetland uses and prohibitions on future use. to contain hydric (wetland) soils, and does not MCL 324.30301-324.30329 demonstrate signs of hydrology that would support a wetland. If additional information indicating the drainage ditch area is a wetland becomes available, then the substantive requirements of these regulations may be potentially Relevant and Appropriate. TABLE 5-3 Other Regulatory Consideration Velsicol Burn Pit Superfund Site, St. Louis, Michigan

Regulation Requirement ARAR Status Analysis

Part 115, Solid Waste Management, NREPA Addresses solid waste management including Not an ARAR Relevant and appropriate for remedial action and general landfill design requirements. Regulates alternatives that include soil cover systems for non- the construction and operation of sanitary hazardous solid waste. Provides requirements for landfills, solid waste transfer facilities, and solid closure and post-closure of non-hazardous solid waste MCL 324.11501 et seq, and waste processing plants. Specifies liner and treatment, storage, and disposal facilities. Provides capping requirements for solid waste landfills. groundwater quality performance standards. May Part 115 Rules, MAC R 299.4101-4122 Requirements for the operation and closure of serve as a basis of design for containment of non- non-hazardous waste treatment, storage, and hazardous solid waste onsite. disposal and groundwater quality performance standards. Also imposes geographic limitations on where non-hazardous solid waste can be disposed.

Michigan Occupational Safety and Health Establishes rules for safety standards in the Not an ARAR Onsite remedial actions have the potential to expose Act (M10SHA), Act 154 of 1974. (MCL workplace. workers to contaminants. Construction, excavation 408.1001-1094). and other site actions may present potential health hazards to workers. Human labor could construct remedial systems and provide long-term maintenance MIOSHA Rules: on the systems. Such activities are governed by worker Part 4 through 13 of the Al! Industry safety and health standards under this act and Administrative Rules, Part 1 through 91 MIOSHA standards and safety standards must be (including the General Rules) of followed for all site actions and activities. Construction , Safety Standards Commission Rules, Part 1 through 93 ofthe General Industry Safety Standards Commission Rules, and Part 301 through 681 of the Occupational Health Standards Commission Rules

Michigan Vehicle Code, 1949 PA 300 as Statute governs the reduction of maximum axle Not an ARAR Remedial action and construction may require heavy amended, MCL 257.716-257.750 loads during springtime frost periods and loads of equipment, fill dirt, contaminated media, etc. provides for the establishment of rules. to be transported over roadways, however, this is not allowed during frost periods.

Michigan Motor Carrier Safety Act of 1963, Requirements for transporters of hazardous Not an ARAR Protects the public and first responders to hazardous Public Act 181 of 1963 as amended. (MCL materials. incidents and the environment form hazardous 480.11-480.25 etseq) materials. Placarding and container safety requirements may apply to shipments or loads that originate on site. Table 6

Cost Comparison for Total Costs of Remedial Alternatives Velsicol Burn Pit Site Date 2/7/14 St. Louis, Michigan Base Year 2014 Focused Feasibility Study Supplement

Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5 No Action Soil Containment and Capping, In-Situ Soil Stabilization, Soil In-Situ Thermal Treatment, Soil Hot Spot Excavation and ICs and Monitoring Cover, ICs and Monitoring Cover, ICs and Monitoring Disposal

Main Components No Action Installation of a 24-inch low Complete In-situ solidification of Complete In-situ Thermal Installation of a perimeter shoring permeability soil cap overlain targeted soils down to glacial till, Treatment of targeted soils down system, contaminated soil with a 6-inch topsoil layer with Installation of a 12-inch soil cover to glacial till, Installation of a 12- removal, Subtitle C landfill Institutional Controls and Long overlain with a 6-inch topsoil inch soil cover overlain with a 6- disposal, clean material Term Monitoring layer with Institutional Controls inch topsoil layer with Institutional replacement, seed revegetation, and Long Term Monitoring Controls and Long Term with Institutional Controls Monitoring

Total Project Duration (Years) 30 30 30 30 30

Capital Cost $0 $2,400,000 $12,800,000 $22,400,000 $116,500,000 Initial Annual O&M Cost $0 $50,077 $50,077 $50,077 $0 Total Periodic Cost $0 $90,000 $90,000 $90,000 $90,000

Total Present Value $0 $3,100,000 $13,500,000 $23,100,000 $116,500,000

Disclaimer: The information in this cost estimate is based on the best available information regarding the anticipated scope of the remedial alternatives. Changes in the cost elements are likely to occur as a result of new information and data collected during the engineering design of the remedial alternatives. This is an order-of-magnitude cost estimate that is expected to be within -3D to +50 percent of the actual project costs. Table 7

Alternative: Alternative 4 COST ESTIMATE SUMMARY Name: In-SItu Thermal Treatment, Soil Cover, ICs and Monitoring

Site: Velsicol Burn Pit Site Description: Complete In-situ Thermal Treatment of targeted soils down to glacial till, Installation of a 12-inch soil cover Location: St. Louis, Michigan overlain with a 6-inch topsoil layer with Institutional Controls and Long Term Monitoring Phase: Focused Feasibility Study Supplement Base Year: 2014 Date: 2/7/14

CAPITAL COSTS UNIT DESCRIPTION QTY UNIT COST TOTAL NOTES Institutional Controls Site Development Plan 1 LS $20,000 520,000 Institutional Control Drafting SUBTOTAL $20,000

P redesign Investigations Geotechnical Investigation 1 LS $25,000 $25,000 Geotechnical Borings of Cap Area - 4 to 45 feet SUBTOTAL $25,000

Site Preparation & Infrastructure Modifications PPE and Misc. Waste Disposal 1 LS $15,000 $15,000 General Allowance Silt Fencing 3000 FT $4.52 $13,560 Recent 2013 Supply and Install Quotations Security Fencing/Barricades 3000 FT $10.50 $31,500 Recent 2013 Supply and Install Quotations Connect Residential Home to Municipal Water Supply 2 EA $5,066 $10,133 Assumed 200 feet of connection for each Abandon 2 Residential Wells 2 EA $1,767.38 $3,535 Assumed 25 feet of depth to abandon Clear & Grub 7 AC $4,675.00 $34,125 Assumed total Disturbance area Gravel Entrance 1 LS $6,498.70 $6,409 Assumed 30' X 100' X 12" $73,727 MobiKzation/Demobllization 5% $3,686 Subcontractor General Conditions 15% $11,059 SUBTOTAL $88,473

In-Situ Thermal Treatment and Soil Cover Consolidate Remnant Burn Debris within Cover Limits 962 CY $10.00 $9,620 Recent 2013 Supply and Install Quotations Treatability Study 1 LS $25,000 $25,000 Treatment Selection Thermal Design, Work Plans, Permits 1 LS $189,000 $189,000 Provided By TRS Thermal Electrode Materials Mobilization 1 LS $1,578,000 $1,578,000 Provided By TRS Thermal subsurface Installation 1 LS $1,609,000 $1,609,000 Provided By TRS Thermal Surface Installation and Start-up 1 LS $897,000 $697,000 Provided By TRS Thermal Remediation System Operation 1 LS $2,871,000 $2,871,000 Provided By TRS Thermal Equipment Demobilization and Final Report 1 LS $373,000 $373,000 Provided By TRS Thermal Drilling Cuttings and Wasle Disposal 1 LS $373,000 $373,000 Provided By TRS (Assumes $300 per ton) Electrical Permit and Connection 1 LS $373,000 $373,000 Provided By TRS Electiical Energy Usage 1 LS $2,012,000 $2,012,000 Provided By TRS ($0.09 kWh) Sub Grade Fill/Grading 27,000 CY $12,00 $324,000 Recent 2013 Supply and Install Quotations 12-Inch Compacted Clay Soil 6,615 CY $15.00 $99,225 Recent 2013 Supply and Install Quotations 6-inch Topsoil Layer 3,308 CY $32.00 $105,856 Recent 2013 Supply and Install Quotations $10,838,701 Mobifization/Demobiiization 5% $541,935 Subcontractor General Conditions 15% $1,625,805 SUBTOTAL $13,006,441

Site Restoration Perimeter Swale 1.700 LF $5.50 $9,350 2 feet wide bottom trapezoid, 2 feet deep Erosion Control Matting 1.500 SY $3.57 $5,355 Recent 2013 Supply and Install Quotations Seeding 5 AC $3,184.00 $16,875 Recent 2013 Supply and Install Quotations Permanent Fencing 1,700 LF $27.50 $46,750 Recent 2013 Supply and Install Quotations Monitoring Well Installation - 2-inch Stainless Steel 6 EA $3,DOO.0D $1B,000 Recent 2013 Supply and Install Quotations SUBTOTAL $96,330 Mobilization/Demobilization 5% $4,817 Subcontractor Genera! Conditions 15% $14,450 SUBTOTAL $115,586

Contractor Oversight Field Inspections of Soil Placement/Compaction 240 Hour $75,00 $18,000 3 weeks of subgrade and clay placement Geotechnical Laboratory Testing 1 LS $30,000.00 $30,000 Various Geotechnical Tests EPA Oversight of RA 20 Week $6,000.00 $120,000 1 person, 12 hours per day, 5 days a week EPA Oversight Per Diem 20 Week $1,000.00 $20,000 Lodging, truck, food and gas SUBTOTAL $188,000

SUBTOTAL $13,440,000 General Contractor 12.0% $1,612,800 Contingency 25% $3,360,000 10% Scope + 15% Bid Escalation 2014 1.6% $294,605 SUBTOTAL $18,707,4D5

Project Management 5% $935,370 USEPA 2000, p. 5-13, >$10M Remedial Design 6% $1,122,444 USEPA 2000, p. 5-13, >$10M Construction Management 6% $1,122,444 USEPA 2000, p. 5-13, >$10M P&P Bonds 2.5% $547,192 SUBTOTAL $3,727,450

TOTAL CAPITAL COST I $22,400,000 Alternative: Alternative 4 COST ESTIMATE SUMMARY Name: In-Situ Thermal Treatment, Soil Cover, ICs and Monitoring

OPERATIONS AND MAINTENANCE COST UNIT DESCRIPTION QTY UNIT COST TOTAL NOTES

Inspection and Repair Annual Cover Inspections 20 Hour $110 $2,200 2 inspections per year Mowing 3 LS $2,000 $6,000 3 mowing events per year Animal Burrow Allowance 1 LS $2,500 $2,500 Allowance Cover Repair Allowance 1 LS $2,500 $2,500 Allowance Fence Repair Allowance 1 LS $1,500 $1,500 Allowance SUBTOTAL $14,700 Water Sampling for 2 events GW Sampling, Level D Bi-Annual Ground Water Sampling 14 EA $500.00 $7,000.00 6 wells, 2 events per year, VOCs, SVOCs, Metals + 2 QC samples Labor 32 HRS $110 $3,520 1 person crew Equipment - meters 1 LS $1,200 $1,200 Consumables 1 LS $350 $350 Travel 1 LS $500 $500 Data Validation 6 HRS $110 $660 Reporting 10 HRS $110 $1,100 SUBTOTAL $14,330

SUBTOTAL FOR EACH YEAR $29,030 Inspections/Repairs per year

Allowance for Misc. Items 20% $5,806 SUBTOTAL FOR EACH YEAR $34,836

Contingency 25% $6,709 10% Scope + 15% Bid SUBTOTAL FOR EACH YEAR $43,545

Project Management & Technical Support 15% $6,532

TOTAL ANNUAL 08.M COST $50,077 Reflects Semi annual sampling

PERIODIC COSTS UNIT DESCRIPTION YEAR QTY UNIT COST TOTAL NOTES

5 year Review 5 1 LS $15,000 $15,000 5 year Review 10 1 LS $15,000 $15,000 5 year Review 15 1 LS $15,000 $15,000 5 year Review 20 1 LS $15,000 $15,000 5 year Review 25 1 LS $15,000 $15,000 5 year Review 30 1 LS $15,000 $15,000 Total $90,000

TOTAL ANNUAL PERIODIC COST $90,000

PRESENT VALUE ANALYSIS Discount Rate = 7.0%

TOTAL COST DISCOUNT COST TYPE YEAR TOTAL COST PER YEAR FACTOR PRESENT VALUE NOTES

CAPITAL COST 0 $22,400,000 $22,400,000 1.000 $22,400,000 ANNUAL O&M COST 1 to 30 $1,502,303 $50,077 12.4 $621,404 PERIODIC COST 5 $15,000 $15,000 0.71 $10,695 PERIODIC COST 10 $15,000 $15,000 0.51 $7,625 PERIODIC COST 15 $15,000 $15,000 0.36 $5,437 PERIODIC COST 20 $15,000 $15,000 0.26 $3,876 PERIODIC COST 25 $15,000 $15,000 0.18 $2,764 PERIODIC COST 30 $15,000 $15,000 0.13 $1,971 $24,000,000 $23,053,772

TOTAL PRESENTVALUE OF ALTERNATIVE $23,100,000

SOURCE INFORMATION

1. United States Environmental Protection Agency. July 2000. A Guide to Preparing and Documenting Cost Estimates During the Feasibility Study. EPA 540-R-00-D02. (USEPA, 2000). This is an order-of-magnitude cost estimate that is expected to be within -30 to +50 percent ofthe actual project costs.