Document Moscow_doc_807a0beb5e

Analysis of Brownfields Cleanup Alternatives for the Former Sharpe Oil Site in Moscow, Idaho Prepared for: and 206 E. 3rd Street Moscow, Idaho 83843 Prepared by: TerraGraphics Environmental Engineering, Inc. 988 S. Longmont Avenue, Suite 200 Boise, Idaho 83706 www.terragraphics.com August 15, 2016 ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho ii Table of Contents Section 1.0 Introduction 1 1.1 Purpose 1 1.2 Scope 1 1.3 Report Structure 1 Section 2.0 Background, Site History, and Previous 3 2.1 Background 3 2.2 Site History 3 2.3 Previous Assessments 4 2.4 Summary 6 2.4.1 1102 South Main Street Site 6 2.4.2 Property to the North 7 Section 3.0 Development of Clean-up Goals and Objectives 8 3.1 Land Use 8 3.1.1 Current Land Use 8 3.1.2 Regional Land Use 8 3.1.3 Water Use 8 3.2 Site Hazards and Contaminants of Concern 8 3.3 Exposure Pathways 8 3.4 Applicable Standards 9 3.5 Cleanup Goals and Objectives 9 Section 4.0 Identification of Cleanup Alternatives 11 4.1.1 Cleanup Alternative 1 – Monitored Natural 11 4.1.2 Cleanup Alternative 2 – Combination of Soil Excavation and Removal and Monitored Natural Attenuation 12 4.1.3 Cleanup Alternative 3 – In-situ Chemical 13 4.1.4 Cleanup Alternative 4 – Combination of Soil Excavation and In-situ Chemical Oxidation 13 4.1.5 Cleanup Alternative 5 – Soil Vapor Extraction With Air Sparging 13 4.1.6 Clean-up Alternative 6 – No-Action 14 Section 5.0 Detailed Analysis of Cleanup Alternatives 15 5.1 Description of Evaluation Criteria 15 5.1.1 Overall Protection of Human Health and the Environment 15 5.1.2 Ease of Implementation 15 5.1.3 Cost 15 5.1.4 Sustainability – Operation and Maintenance and Long-term Effectiveness 15 5.1.5 Ability to Meet Proposed Building and Land Use 16 5.1.6 Short-term Impacts to the Environment – “Green” Remediation Approaches 16 5.2 Detailed Analyses of Alternatives 16 5.2.1 Detailed Analysis of Alternative 1 – Monitored Natural Attenuation 16 5.2.2 Detailed Analysis of Alternative 2 – Combination of Excavation/Removal of Petroleum-contaminated Soils and Monitored Natural Attenuation 17 5.2.3 Detailed Analysis of Alternative 3 – In-situ Chemical Oxidation 18 ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho iii 5.2.4 Detailed Analysis of Alternative 4 – Combination of Soil Excavation and In-situ Chemical Oxidation 19 5.2.5 Detailed Analysis of Alternative 5 – Soil Vapor Extraction and Air Sparging 20 Section 6.0 Comparative Analysis of Clean-up Alternatives 22 6.1 Alternative Ranking Criteria 22 6.2 Summary 22 Section 7.0 References and Resources Used 24 List of Figures Figure 1. 1102 S Main Site Vicinity Map 26 Figure 2. 1102 S Main Sampling Locations Map 27 Figure 3. 1102 S Main Approximate Zone of Soil Contamination Map 28 Figure 4. 1102 S Main Groundwater Contour Map April 2012 29 Figure 5. 1102 S Main Groundwater Contour Map May 2013 30 Figure 6. 1102 S Main Approximate Zone of Groundwater Contamination Map 31 List of Tables Table 11. Comparative Analysis of Clean-up Alternatives 22 Table 1. All Direct Push Soil Sample Analytical Results. 32 Table 2. Soil Boring Sample Analytes Exceeding Petro REM Screening Levels or the REM IDTLs by Exposure Pathway (3 pages). 33 Table 3. Groundwater Elevation 36 Table 4. Field Parameter Data. 37 Table 5. All Groundwater Analytical Results. 38 Table 6. Groundwater Analytes Exceeding Petro REM Screening Levels by Exposure Pathway. 39 Table 7. Soil Vapor Analytical Summary Residential Use (µg/m3). 40 Table 8. Soil Vapor Analytical Summary Industrial Use (µg/m3). 41 Table 9. Ambient Air Analytical Summary Residential Use (μg/m3) 42 Table 10. Ambient Air Analytical Summary Industrial Use (μg/m3) 42 ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho iv Acronyms and Abbreviations ABCA Analysis of Brownfields Cleanup Alternatives AST aboveground storage tank ASTM American Society for Testing and Materials ATSDR Agency for Toxic Substances and Disease Registry bgs below ground surface BMP Best Management Practice BTEX benzene, toluene, ethyl benzene, and total xylenes City City of Moscow CFR Code of Federal Regulations Coalition Greater Moscow Area Coalition COC contaminant of concern DO dissolved oxygen EDB 1,2-dibromoethane EDC 1,2-dichloroethane ESA Environmental Site Assessment ESC ESC Lab Sciences HAZWOPER Hazardous Waste Operations and Emergency Response ICP Institutional Controls Plan IDAPA Idaho Administrative Procedures Act IDEQ Idaho Department of Environmental Quality IDTL Initial Default Target Level IDWR Idaho Department of Water Resources ISCO In-situ chemical oxidation LL low level MCL Maximum Contaminant Level MNA monitored natural attenuation MTBE methyl tert-butyl ether NPDES National Pollutant Discharge Elimination System NTP Notice to Proceed O&M Operation and Maintenance ORP oxidation-reduction potential ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho v OSHA Occupational Safety and Health Act PAH aromatic hydrocarbon PCS petroleum contaminated soil Petro REM Risk Evaluation Manual for Petroleum Releases PID photo-ionization detector QAPP Quality Assurance Project Plan RCRA Resource Conservation and Recovery Act REM Risk Evaluation Manual RSL Regional Screening Level RUSL Residential Use Screening Level SIM selected ion monitoring SVE soil vapor extraction TCLP Toxicity Characteristic Leaching Program TerraGraphics TerraGraphics Environmental Engineering, Inc. UECA Idaho’s Uniform Environmental Covenants Act URA Urban Renewal Agency USEPA U.S. Environmental Protection Agency UST underground storage tank VCP Voluntary Cleanup Program VOC volatile organic compound VRA Voluntary Remediation Agreement Units mg/kg milligram per kilogram mg/L milligram per liter ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 1 Section 1.0 Introduction The City of Moscow (City), through the Greater Moscow Area Coalition (the Coalition) Assessment Grant BF-00J24101 and on behalf of the Moscow Urban Renewal Agency (URA), engaged TerraGraphics Environmental Engineering, Inc. (TerraGraphics) to develop an Analysis of Brownfields Cleanup Alternatives (ABCA) for the property located at 1102 South Main Street in Moscow, Idaho (hereinafter referred to as the “Site,” see Figure 1.1 Purpose The purpose of this ABCA is to describe the evaluation methods used to determine the preferred remedial option to address contamination issues associated with the site. The remedial alternatives are evaluated on the basis of protection of human health and the environment, ease of implementation, cost of remediation, sustainability, ability to meet proposed land use, and short-term impacts to the environment. In accordance with Idaho Administrative Procedures Act (IDAPA) Idaho Land Remediation Rules (IDAPA 58.01.18), this ABCA has identified the remediation standards to ensure that substantial present or probable future risk to human health or the environment is eliminated or reduced to protective levels based upon present and reasonably anticipated future uses of the site (IDAPA 58.01.18(02)b. 1.2 Scope The scope of this ABCA includes the identification, evaluation, and selection of cleanup and management options from nutrient impacted soils and groundwater at the Site. Specific tasks include:  review previous reports and investigations,  establish cleanup goals and objectives,  develop cleanup alternatives in accordance with the Site cleanup goals,  describe criteria used to compare cleanup alternatives, and  recommend a preferred alternative based on future land use. 1.3 Report Structure Section 1 Introduction provides an overview and brief description of the purpose and scope of the ABCA. Section 2 Background, Site History, and Previous Assessments includes a brief site history and a summary of prior environmental investigations at the Site. Additionally, this section provides conclusions for the properties involved (the Site or the property north of the Site) and matrices involved (soil, groundwater, soil vapor, and ambient air). This section also presents conclusions for the Idaho Risk Evaluation Manual for Petroleum Releases (Petro REM) results using Site soil and soil vapor concentrations. Section 3 Development of Cleanup Goals and Objectives includes a discussion of the current and future land use, contaminants of concern (COCs), and identified cleanup objectives and goals for the Site. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 2 Section 4 Identification of Cleanup Alternatives identifies and describes proposed cleanup alternatives. Section 5 Detailed Analysis of Cleanup Alternatives describes the criteria used to evaluate the proposed cleanup alternatives. Section 6 Comparison Analysis of Cleanup Alternatives compares the analysis of the four proposed alternatives against the evaluation criteria and ranks them based on scores of (low success) to (high success), producing a preferred alternative with the best ranking score. Section 7 References and Resources Used provides references for reports cited and used for resource information in this document. Figures and Tables are provided at the end of the report. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 3 Section 2.0 Background, Site History, and Previous Assessments 2.1 Background The City was awarded a U.S. Environmental Protection Agency (USEPA) Brownfields Assessment Coalition Grant (for hazardous substances contamination and petroleum contamination) on August 2010. The City is using the USEPA grant funds to conduct Phase I and II Environmental Site Assessments (ESAs), as well as ABCAs for multiple Brownfield properties along a former railroad/industrial corridor, future industrial park property, and other negatively impacted and/or stigmatized areas. 2.2 Site History In the 1950s, Mobil Oil occupied the Site with a bulk petroleum plant, warehouse, and office. In the years to follow several owners bought and sold the Site and used it for the same purpose. In the 1970s, the property owner and operator was Handel-Langley. There was a Mobil Service Station operating on the property; however, the exact years of operation are unknown. The current owner is Fields Holdings, Inc. who purchased the Site in 2015 with the intent to redevelop the property into student housing and commercial retail space. The most recent former owner is Ted Sharpe, Junior. In 1981, Ted Sharpe, Senior, bought the property and renamed the Site Sharpe Oil. At that time there were four 10,000-gallon aboveground storage tanks (ASTs), a 500-gallon underground storage tank (UST) near the loading dock of the warehouse building, a fuel truck, and a commercial dispensing island (between the service station and warehouse building) with underground piping in operation at the business. Mr. Sharpe, Senior, operated the property as Sharpe Oil Corp. until 1999, at which time the business was sold but not the property. Mr. Sharpe, Senior, had the UST, the piping, and the dispensers purged and removed in 1999 by Kennedy Equipment, and conducted a Tier 1 remediation with the assistance of the Idaho Department of Environmental Quality (IDEQ). Soil samples were collected; there was no evidence of soil contamination and the area was backfilled. A few years later, the ASTs were removed. The property contained offices and general storage for Sharpe Apartments after 1999. Petroleum-contaminated soil (PCS) was discovered when the Site warehouse building was demolished in 2008 (Sharpe 2008). All buildings on the north parcel (see Appendix A) were removed in April 2008. The former UST area was excavated in early July 2008 to investigate for residual PCS. Contamination was found in this area, including the areas where the fuel delivery trucks had parked while filling the tanks, and around the former fuel pump mounted on the loading dock. On July 9, 2008, an initial soil sample was collected from a pile of greenish gray silty clay excavated about 2 feet below ground surface (bgs). The sample was analyzed for volatile organic compounds (VOCs) and aromatic hydrocarbons (PAHs); concentrations were detected above the Initial Default Target Levels (IDTLs; IDEQ 2004). During additional excavation, contamination was also observed at approximately 4 feet to 5 feet bgs. Soil was excavated until there was no visible contamination or odor detected in the side walls or bottom of the pit, which was about 30 feet long and 16 feet to 18 feet wide, with a depth of approximately 5 feet to 6 feet bgs. The PCS was taken to the Roach landfill near Lewiston, Idaho. Additional soil samples were collected on September 4, 2008, from three locations within the excavated pit, mostly near the bottom, and were analyzed for VOCs and PAHs to confirm ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 4 adequate removal. All analytes from those samples exhibited concentrations below Risk Evaluation Manual (REM) IDTLs (IDEQ 2004). Groundwater was not sampled at this time. Shallow groundwater was sampled in June 1997 and again in 2009 from two existing monitoring wells located north of the subject property (see Appendix A for an historical map) (Sharpe 2008 and 2009). The wells were installed in 1996 for the Idaho Transportation Department for the Moscow Couplet South Connector project preliminary site investigation (Sharpe 2008). Monitoring well MW-15 is located north of the former office/warehouse and south of the Latah Trail diversion (gravel path). Monitoring well MW-14 is located north of the former ASTs, just north of the Latah Trail diversion. The June 1997 data did not show any petroleum analytes above their respective detection limits. MW-15 was sampled on May 28, 2009, and analyzed for VOCs, and sampled again on August 11, 2009, and analyzed for PAHs. Monitoring well MW- 14 was also sampled on August 11, 2009, and analyzed for VOCs and PAHs. Results for MW- 15 were compared to IDTLs and indicated certain VOCs (benzene, and toluene) exceeded IDTL values; PAH concentrations were below the IDTLs. Samples from MW-14 did not have VOC or PAH concentrations that exceeded the IDTLs. 2.3 Previous Assessments The following provides a summary of the investigations that has occurred at the Site and the property. All work was completed according to the Quality Assurance Project Plan (QAPP): 1102 South Main Street Moscow, Idaho Phase II Environmental Site Assessment (TerraGraphics and STRATA 2012) and the addenda (TerraGraphics and STRATA 2013, TerraGraphics 2013). 1. In April 2012 TerraGraphics advanced 9 direct push soil borings, collected 12 soil samples from the borings, and analyzed the samples for VOCs, PAHs, and total lead. TerraGraphics compared the sample results to the following screening levels: 1) Residential Use Screening Levels (RUSLs) listed in Table 2 of the Petro REM (IDEQ 2012) for VOCs and select PAHs, and 2) IDTLs listed in Appendix A of IDEQ’s REM (IDEQ 2004) for non-petroleum constituents such as certain PAHs and lead. The Petro REM soil RUSLs are specific to each compound for the exposure pathway that generates the most risk to the receptors via vapor intrusion, direct contact, and groundwater protection. A sample concentration may exceed any or all three of the exposure pathways. Figure 2 shows the sample locations for the April 2012 sampling event and Table 1 lists the analytical results and screening levels. Table 2 lists RUSLs, IDTLs, and their exposure pathways that were exceeded. TerraGraphics installed two groundwater monitoring wells onsite (MW-1, which is considered the upgradient well, and MW-2), measured and recorded when field parameters stabilized (pH, dissolved oxygen [DO], oxidation-reduction potential [ORP], and temperature), collected groundwater samples from those wells and from the two existing wells on the property to the north (MW-14 and MW-15, which are considered downgradient wells), and analyzed the samples for VOCs, PAHs, and total lead. TerraGraphics compared the results to the following screening levels: 1) RUSLs listed in Table 2 of the Petro REM (IDEQ 2012) for VOCs and select PAHs, and 2) IDTLs listed in Appendix A of the REM (IDEQ 2004) for non-petroleum constituents such as certain PAHs and lead. The Petro REM groundwater RUSLs are specific to the vapor intrusion and ingestion exposure pathways. A concentration may exceed one or both of the ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 5 exposure pathways. The IDTLs are specific to ingestion as the critical pathway and many are the USEPA Maximum Contaminant Levels (MCLs). MW-2 and MW-15 had benzene, toluene, and naphthalene concentrations that exceeded their screening levels. Figure 4 provides a groundwater contour map based on the four groundwater monitoring wells and shows that groundwater trends toward the northwest. Table 3 provides groundwater elevation data. Table 4 provides field parameter data. Table 5 summarizes groundwater analytical results compared to screening levels and Table 6 lists RUSLs and their exposure pathways that were exceeded. 2. TerraGraphics conducted additional sampling in April and May 2013 to determine the areal extent of the soil and groundwater contamination at the Site and on the property to the north (considered downgradient). TerraGraphics advanced 15 direct push soil borings, collected 17 soil samples, and analyzed them for VOCs, PAHs, and total lead. The central portion of the Site had the highest concentrations, likely due to the historical use in this area. The southwest area of the AST concrete pad also had relatively higher concentrations. Figure 3 provides an approximate zone of soil contamination. Table 1 lists the analytical results and screening levels. Table 2 lists RUSLs, IDTLs, and their exposure pathways that were exceeded. TerraGraphics installed three additional groundwater monitoring wells on the property to the north (MW-3, MW-4, and MW-5), collected groundwater samples from all new and existing wells, and analyzed them for VOCs, PAHs, and total lead. MW-2, MW-3, and MW-15 had benzene, and naphthalene concentrations that exceeded their screening levels. Figure 5 provides a groundwater contour map based on the seven groundwater monitoring wells and shows that groundwater trends toward the north. Table 3 provides groundwater elevation data. Figure 6 illustrates an approximate zone of contamination (plume) based on groundwater samples with analyte concentrations that exceeded the screening levels. Concentrations of analytes in MW-2 and MW-15 decreased from the 2012 to 2013 sampling events with the exception of naphthalene in MW-15. Based on the limited information, it is difficult to determine if this constitutes a decreasing trend at this time. Table 4 provides field parameter data. Table 5 summarizes groundwater analytical results compared to screening levels and Table 6 lists RUSLs and their exposure pathways that were exceeded. TerraGraphics installed three deep soil vapor point wells (VP-1 and VP-2 on the property to the north and VP-3 onsite), installed one sub-slab vapor point onsite (SSW), collected samples from the vapor point wells and the sub-slab vapor point located near the former Domino’s Pizza building, and analyzed the samples for VOCs. TerraGraphics compared the concentrations to RUSLs (IDEQ 2012) and USEPA’s 2012 version of the Regional Screening Levels (RSLs) for Chemical Contaminants at Superfund Sites (USEPA 2012) for residential use air and industrial (commercial) use air1. Table 7 lists the deep and sub- slab soil vapor sample results compared to the residential use RSLs. Naphthalene exceeded the residential RSL in VP-1 (offsite), benzene and exceeded the 1 Deep soil vapor samples are those collected 3 to 5 feet below ground surface. IDEQ’s Petro REM RUSLs are 100 times USEPA’s RSLs for deep soil vapor samples. Sub-slab soil vapor samples are those collected just below the slab on grade building structure. IDEQ’s Petro REM RUSLs are 10 times USEPA’s RSLs for sub-slab soil vapor samples. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 6 residential RSL in VP-3 (onsite), and benzene, and naphthalene exceeded the residential RSL in the sub-slab vapor point (SSW). Table 8 lists the deep and sub-slab soil vapor sample results compared to the industrial (commercial) use RSLs. Benzene was the only COC to exceed the industrial RSL in VP-3 (onsite) and SSW (sub-slab). 3. To further characterize potential ambient air and soil vapor pathways, in September 2013 TerraGraphics collected two indoor ambient air samples from the former Domino’s Pizza building, installed one additional deep soil vapor point well at the east side of the Site (VP-4), collected one deep soil vapor sample from VP-4, and analyzed the samples for VOCs. Concentrations did not exceed residential or industrial RSLs (Table 7 and TerraGraphics compared the ambient air concentrations to the 2012 version of USEPA’s residential use and industrial use ambient air RSLs (USEPA 2012). Table 9 lists the ambient air sample results compared to the residential use RSLs, and Table 10 lists the ambient air sample results compared to the industrial use RSLs. Benzene exceeded the residential RSL at both locations inside the building. No other COCs exceeded the residential RSLs and no COCs exceeded the industrial use RSLs. 4. Since there were COCs that exceeded risk-based screening levels at the Site and on the property to the north, TerraGraphics conducted a Risk Evaluation (RE) using the first version of the Petro REM software (IDEQ 2012). For the Site, results from the Petro REM using Site soil concentrations show the Site meets the acceptable cancer risk level (10-6) and noncarcinogenic hazard index (1.0) for the construction worker scenario. Results from the Petro REM using soil vapor concentrations show the Site meets the acceptable cancer risk level for the non-residential and residential receptors in the area near the former Domino’s Pizza building. 2.4 TerraGraphics did not use data from the northern property to run the RE for the northern property since soil vapor concentrations from samples were lower than soil vapor sample concentrations from the Site. Therefore, TerraGraphics used the Site soil vapor results in the 2012 software version of the PetroREM, and those model results indicated that concentrations were below the acceptable cancer risk level (10-6) and noncarcinogenic hazard index (1.0) for the nonresidential and residential receptors. Summary 2.4.1 1102 South Main Street Site Petroleum concentrations in soil were generally highest in areas near historical contamination/cleanup activities in the central area of the Site. Elevated concentrations in the eastern area of the Site may be due to piping failures from the historical ASTs. Groundwater flow is toward the north. The upgradient groundwater well (MW-1) did not have analytes that exceeded the screening levels. The downgradient onsite well (MW-2), located in the northwest area of the Site and downgradent of the soil contamination, had concentrations of benzene, naphthalene, and toluene in groundwater that exceed screening levels intended to be protective of ingestion MCLs) and the indoor inhalation of vapor emissions routes of exposure. Groundwater in the northern area of the Site does not meet drinking water standards. Based upon the soil vapor data that predicted potential indoor vapor issues, TerraGraphics conducted ambient air monitoring within the former Domino’s Pizza building. Ambient air data indicate levels of VOCs are acceptable for commercial use, but not residential use. These data ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 7 suggests vapors are not migrating from the soils/shallow groundwater to the interior of the building at concentrations above the commercial use screening levels. Although the Petro REM RE (using soil vapor data) show the Site is acceptable for all scenarios, results from ambient air samples collected inside the former Domino’s Pizza building show concentrations exceed screening levels for residential use. The current commercial use of the property is acceptable. 2.4.2 Property to the North Data from soil borings on the northern area of the 1102 South Main Street Site suggest petroleum within the soil has not migrated into the property to the north. However, petroleum analytes appear to have migrated off Site through groundwater. The leading edge of the groundwater contamination plume appears to be near MW-3 (Figure Soil vapor data collected in VP-2 suggests there is a high likelihood for contaminants to migrate from groundwater to the vapor phase and pose a risk within buildings; however, soil vapor impacts appear to be limited to the southwestern-most portion of the northern property and do not appear to extend further north or east at this time. TerraGraphics ran the Petro REM using soil vapor concentrations from the 1102 South Main Street Site, which are greater than soil vapor concentrations collected from the property to the north. These conservative model results indicate site conditions at the property to the north are acceptable for all site users. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 8 Section 3.0 Development of Clean-up Goals and Objectives 3.1 Land Use 3.1.1 Current Land Use The site is owned by Fields Holdings, Inc. and is currently vacant. The adjacent property to the north is also owned by Fields Holdings, Inc. The existing building, the former Domino’s Pizza, AST pad, and the asphalt covered area are scheduled to be removed in preparation for the construction of three to four student townhouse units mixed with commercial retail space. Cleanup target levels vary depending on whether the land use is residential or non-residential as defined by IDEQ’s Petro REM (IDEQ 2012). Therefore, evaluating current and reasonably likely future land uses at the Site and property to the north is critical in determining cleanup target levels and potential exposure points, exposure pathways, and exposure factors. The Site is proposed for both residential and commercial retail use. 3.1.2 Regional Land Use The City is in western central Idaho situated along the state border with Washington, with a population of 23,800. The county seat and largest city of Latah County, Moscow is the home of the University of Idaho. The City contains over 60% of the county’s population and while the university is the dominant employer in Moscow, the City also serves as an agricultural and commercial hub for the Palouse region. West of the Site, across Highway 95, is the University of Idaho campus. To the south and east of the Site is private residential property. To the north is a former railroad line and the future location of 154 units of student housing as part of the same development. 3.1.3 Water Use The Site does not use surface water or shallow groundwater as water sources since it is connected to City water. Five groundwater monitoring wells were installed onsite and two wells were installed on the property to the north for long-term groundwater monitoring. 3.2 Site Hazards and Contaminants of Concern Site sampling has shown that benzene, toluene, and total xylenes (BTEX) and naphthalene in soil and BTEX, naphthalene, and EDC in groundwater are present at the Site in concentrations that exceed the RUSLs and are the recognized Site COCs. 3.3 Exposure Pathways Based on the RE, Residential (including child and age-adjusted) receptors, Non-residential receptors, and Construction Worker receptors had the following primary exposure pathways of concern: ingestion and dermal contact of contaminated soil, and inhalation of contaminated dusts or soil vapors. Although no groundwater is currently being used or is planned on being used for drinking water at the Site, some site COCs could migrate offsite. TerraGraphics considers the groundwater ingestion pathway potentially complete (following the Ground Water Quality Rule; ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 9 IDAPA 58.01.11 Sections 200 and 400) due to the offsite migration and potential drinking water uses on those offsite properties. 3.4 Applicable Standards Cleanup actions at the Site must provide for adequate protection of human health and the environment based on the current and potential future uses of the property. Several human and ecological health standards are relevant to the Site and should be considered during and after cleanup. These standards include the following. Soils  Idaho RUSL: These screening levels are the most conservative medium-specific levels and meeting these levels allows unrestricted (residential) use of the property. Since exposure to these low levels of contaminants does not pose a threat to human health, their application does not require the evaluation of site-specific exposure pathways, the development of a site conceptual model, or any land use restrictions. Groundwater  The National Primary Drinking Water Standards set MCLs for public drinking water supply systems. No groundwater will be developed for drinking at the Site. All premises within the City of Moscow must connect to the city’s drinking water system, and the system must comply with Idaho Rules for Public Drinking Water Systems (IDAPA 58.01.08).  Idaho Water Quality Standards in the Ground Water Quality Rule (IDAPA 58.01.11) require protection of State waters for appropriate beneficial uses and establish State water quality standards for toxic substances for the protection of aquatic life and human health. o Groundwater Quality Protection (established 3-20-97). It is the policy of the State of Idaho to maintain and protect the existing high quality of the State’s groundwater. o Existing and Projected Future Beneficial Uses (established 3-20-97). The policy of the State of Idaho is that existing and projected future beneficial uses of groundwater shall be maintained and protected, and degradation that would impair existing and projected future beneficial uses of groundwater and interconnected surface water shall not be allowed. o Prevention of Groundwater Contamination (established 7-1-98). The policy of the State of Idaho is to prevent contamination of groundwater from all regulated and non-regulated sources of contamination to the maximum extent practical. 3.5 Cleanup Goals and Objectives The overall goal of this ABCA is to reduce or eliminate exposures to physical, environmental, and health hazards at the Site for the proposed Site use. The current and anticipated future uses of the Site are residential and commercial retail space and are considered in the evaluation of cleanup objectives. In addition, the following pathways are considered in the evaluation: direct contact with soil, indoor inhalation from vapor intrusion, ingestion of soil or groundwater, and ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 10 the protection of groundwater. Cleanup actions at the Former Sharpe Oil site must provide for adequate protection of human health and the environment based on the current and future uses of the property. Cleanup target levels will be defined by the RUSLs as identified in IDAPA 58.01.24 Standards and Procedures for Application of Risk Based Corrective Action at Petroleum Release Sites. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 11 Section 4.0 Identification of Cleanup Alternatives The following analysis was performed to consider a range of reasonable and proven response actions and cleanup alternatives based on contaminant concentrations, site characteristics, current and proposed site use, cleanup goals, associated human health hazards, and potential exposure pathways. This section presents a compilation of potentially applicable technologies for the remediation of the identified COCs described above. The objective of this analysis is to identify alternatives to be evaluated further in Section 5.0. For each of the potentially applicable alternatives, a brief description of the alternative and a short discussion of its advantages and disadvantages are presented. Six options are considered for the Former Sharpe Oil site: 1. Monitored natural attenuation. 2. A combination of contaminated soil removal with monitored natural attenuation. 3. In-situ chemical oxidation. 4. A combination of excavation and in-situ chemical oxidation. 5. Soil vapor extraction with air sparging. 6. No-Action. 4.1.1 Cleanup Alternative 1 – Monitored Natural Attenuation Description Monitored natural attenuation (MNA) is the reduction in the concentration and mass of a substance and its breakdown products in soil and/or groundwater due to naturally occurring physical, chemical, and biological processes without human intervention or enhancement. These processes include, but are not limited to, dispersion, diffusion, sorption and retardation, and degradation processes such as biodegradation and abiotic degradation (USEPA 1999). Advantages  MNA may be less intrusive and disruptive of the Site and its infrastructure.  This option may produce less waste, use less energy, and may require less operation and maintenance (O&M) costs. Therefore, overall costs may be less.  MNA does not generate remediation wastes. However, risks from methane produced during natural biodegradation of petroleum hydrocarbons may be a concern.  There is reduced potential for cross-media transfer of contaminants commonly associated with ex-situ treatment.  There is reduced risk of human exposure to contaminants near the source area.  Natural biodegradation may result in the complete destruction of contaminants in-situ. Disadvantages  An accurate Site conceptual model should be developed to confirm that Site characteristics are favorable for MNA.  The estimated timeframe of MNA may not be comparable to an active remediation method. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 12  MNA May fail to achieve the desired cleanup levels within a reasonable length of time (and an engineered remedy should instead be selected).  MNA may require institutional controls to ensure protection of human health and the environment through land use restrictions such as constructing vapor barriers and restricting water use.  MNA is not suitable when contamination has impacted a receptor impacted groundwater supply well, vapor intrusion in a building).  Despite predictions that the contaminants are stationary, some migration of contaminants may occur. Therefore, MNA is not suitable if receptors might be affected. As a result, performance monitoring will generally require more monitoring locations and monitoring will extend over a longer period of time.  It may be necessary to implement contingency measures. If so, this may increase the overall cost of the remediation.  MNA may be accompanied by changes in groundwater geochemistry that can mobilize other contaminants. 4.1.2 Cleanup Alternative 2 – Combination of Soil Excavation and Removal and Monitored Natural Attenuation Description The previously identified petroleum-contaminated soils will be excavated, removed, and land- farmed, and the resultant excavation pit will be backfilled and compacted with clean soil. Groundwater will be monitored to ensure that any remaining contamination is not migrating offsite and that the overall contaminant mass is reducing over time. Advantages  The source of continued petroleum contamination at the Site will be removed.  Ongoing monitoring will provide information to aid in complete Site closure.  This cleanup method can be implemented with minimal disturbance to Site operations.  This cleanup method requires no removal, treatment, storage, or discharge considerations for groundwater. Disadvantages  There are additional costs to continue Site monitoring.  It may not be possible to remove all contaminated soil from the Site. Institutional controls, such as land use restrictions, may be required to ensure the protection of human health and the environment by limiting exposure to any remaining COCs and protecting the integrity of the remedy.  Shallow groundwater may limit the depth of excavation. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 13 4.1.3 Cleanup Alternative 3 – In-situ Chemical Oxidation Description In-situ chemical oxidation (ISCO) involves the introduction of a chemical oxidant into the subsurface for the purpose of transforming groundwater or soil contaminants into less harmful chemical species. ISCO results in the transformation of a wide range of environmental contaminants and enhances mass transfer. The two most commonly used forms of injected oxidants are permanganate (MnO4-) and Fenton’s Reagent (hydrogen peroxide [H2O2] and Ferrous iron [Fe+2]) or catalyzed hydrogen peroxide. Advantages  Reduces the anticipated cleanup times required for MNA and other remedial options.  This cleanup method can be implemented with minimal disturbance to Site operations.  This cleanup method requires no removal, treatment, or storage considerations for groundwater. Disadvantages  Efforts to stabilize the reaction rate in the subsurface are needed to enhance transport distances and persistence.  This cleanup method may require a pilot test to determine which oxidant is the most suitable for the Site conditions.  Complex heterogeneous systems involving aquifer materials, soils, and groundwater introduce potential treatment inefficiencies due to imperfect reactive conditions.  Strong oxidants may compromise subsurface utilities. 4.1.4 Cleanup Alternative 4 – Combination of Soil Excavation and In-situ Chemical Oxidation Description The previously identified petroleum-contaminated soils will be excavated, removed, and land- farmed, and the resultant pit will be backfilled with clean soil. ISCO will be implemented to transform the remaining groundwater or soil contaminants into less harmful chemical species. Advantages  This cleanup method reduces the anticipated cleanup times required for MNA and other remedial options.  This cleanup method can be implemented with minimal disturbance to Site operations.  This cleanup method requires no removal, treatment, or storage considerations for groundwater. Disadvantages  There are additional costs to continue Site monitoring.  Several injection sites may be needed to provide an adequate radius of influence. 4.1.5 Cleanup Alternative 5 – Soil Vapor Extraction With Air Sparging Description ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 14 Soil Vapor Extraction (SVE) is a remedial technology that removes volatile and some semi- volatile contaminants from the subsurface by applying a vacuum and inducing a controlled flow of air. A vacuum blower, connected to SVE wells that are screened above the groundwater table, is used to capture the soil gas and transport it above ground for treatment. Air sparging is an in-situ remedial technology that reduces concentrations of volatile constituents in petroleum products that are adsorbed to soils and dissolved in groundwater. This technology, which is also known as “in-situ air stripping” and “in-situ volatilization,” involves the injection of contaminant-free air into the subsurface saturated zone, enabling a phase transfer of hydrocarbons from a dissolved state to a vapor phase. The air is then vented through the unsaturated zone. Air sparging is most often used together with SVE, but it can also be used with other remedial technologies. Air sparging is generally more applicable to the lighter gasoline constituents BTEX) because they readily transfer from the dissolved to the gaseous phase. Advantages  There is readily available equipment with easy installation for this method.  This cleanup method can be implemented with minimal disturbance to Site operations.  This option has short treatment times; usually less than 1 to 3 years under optimal conditions.  This cleanup method is proven as highly effective for remediating BTEX constituents.  This option requires no removal, treatment, storage, or discharge considerations for groundwater.  SVE with air sparging promotes in-situ biodegradation. Disadvantages  Soil with a high organic contact or that is extremely dry has a high sorption capacity and reduces vapor removal.  Stratified soils may cause air sparging to be ineffective.  Some interactions among complex chemical, physical, and biological processes are not well understood. 4.1.6 Clean-up Alternative 6 – No-Action Description The No-Action alternative assumes no remediation actions will be undertaken at the Site and must be considered as part of the comparative analysis process. Advantages  Cleanup costs of this alternative would be zero, although limited costs have already been incurred for site investigations. Disadvantages  This would prevent the use of the Site including future development due to risks posed to users including inhalation, direct contact, and ingestion during construction activities. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 15 Section 5.0 Detailed Analysis of Cleanup Alternatives 5.1 Description of Evaluation Criteria The cleanup alternatives identified for the Site (see Section 4.0) are evaluated in this section based on the following performance criteria: 1. Overall protection of human health and the environment 2. Ease of implementation 3. Cost of remediation 4. Sustainability – O&M and long-term effectiveness 5. Ability to meet proposed building use 6. Short-term impacts to the environment – “green” remediation approaches The following subsections describing these performance criteria serve as a basis for conducting a comparative analysis of the proposed remedial alternatives. 5.1.1 Overall Protection of Human Health and the Environment This criterion is used to evaluate whether human health and the environment are adequately protected. Human health protection includes reducing risk to acceptable levels, either by reducing contamination concentrations or eliminating potential routes for exposure by implementing specific training to meet regulatory requirements. Environmental protection includes minimizing or avoiding negative impacts to natural, cultural, and historical resources. 5.1.2 Ease of Implementation Ease of implementation refers to the technical and administrative feasibility of carrying out an alternative and the availability of the required services and materials. The following factors are considered for each alternative:  The likelihood of technical difficulties in constructing the alternative and delays due to technical problems.  The potential for regulatory constraints to develop as a result of uncovering buried cultural resources or encountering endangered species).  The availability of necessary equipment, specialists, and provisions, as applicable. 5.1.3 Cost This criterion considers the cost of implementing an alternative, including capital costs, O&M costs, opportunity costs, and monitoring costs. 5.1.4 Sustainability – Operation and Maintenance and Long-term Effectiveness Sustainability includes an assessment for the potential need to replace the alternative’s technical components in the long term. In addition, this criterion evaluates the ease of O&M procedures required for the site. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 16 5.1.5 Ability to Meet Proposed Building and Land Use This criterion addresses the clean-up alternative’s ability to meet the requirements for projected reuse proposals. These requirements include the preservation of the site as a whole. 5.1.6 Short-term Impacts to the Environment – “Green” Remediation Approaches This criterion evaluates the potential short-term impacts to the environment as a result of onsite activities. In addition, consideration is made for reducing the overall environmental footprint and impact to the environment as a result of onsite activities. 5.2 Detailed Analyses of Alternatives All of the proposed alternatives have the potential to provide for overall protection of human health and the environment and will be designed so they are in compliance with applicable federal, state, and local regulations. Since a No-Action alternative does not meet the goal for protection of human health and the environment, and current risks at the site are unacceptable for the proposed Site use, this alternative was not evaluated for the cleanup alternatives. 5.2.1 Detailed Analysis of Alternative 1 – Monitored Natural Attenuation  Overall Protection of Human Health and the Environment MNA works best where site conditions are favorable. Under appropriate field conditions, the regulated compounds BTEX may naturally degrade through microbial activity and ultimately produce non-toxic end products carbon dioxide and water). Where microbial activity is sufficiently rapid, the dissolved BTEX contaminant plume may stabilize stop expanding), and contaminant concentrations in both groundwater and soil may eventually decrease to levels below regulatory standards. Following degradation of a dissolved BTEX plume, a residue consisting of heavier petroleum hydrocarbons of relatively low solubility and volatility will typically be left behind in the original source (spill) area. Although this residual contamination may have relatively low potential for further migration, it still may pose a threat to human health or the environment either from direct contact with soils in the source area or by continuing to slowly leach contaminants to groundwater. For these reasons, MNA alone is generally not sufficient to remediate petroleum release sites. Implementation of source control measures in conjunction with MNA is almost always necessary. Other controls institutional controls), in accordance with applicable state and federal requirements, may also be necessary to ensure protection of human health and the environment.  Ease of Implementation Through TerraGraphics’ Site investigations in 2012 and 2013, Site characterization has already been completed. The implementation of Alternative 1 will include installing a monitoring well in the source area to provide baseline levels, to monitor the mass reduction, and to assess if offsite migration is occurring. Monitoring wells could be installed less than 18 feet bgs using a direct push drill rig. Groundwater monitoring should be completed quarterly. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 17  Cost MNA has a relatively low up-front cost that includes the installation of a sufficient number of monitoring wells. However, performance monitoring should continue until remediation objectives have been achieved, and longer if necessary to verify that the Site no longer poses a threat to human health or the environment. Typically, monitoring is continued for a specified period 1 to 3 years) after remediation objectives have been achieved to ensure that concentration levels are stable and remain below target levels. Groundwater monitoring costs are estimated at $15,000 to $20,000 per year.  Sustainability – Operations and Maintenance and Long-term Effectiveness MNA often requires a longer time-frame to meet remedial goals compared to more active remedies. Monitoring is also continued for a specified period 1 to 3 years) after remediation objectives have been achieved to ensure that concentration levels are stable and remain below target levels. Additionally, contingency remedies may need to be established if the contaminant plume does not change.  Ability to Meet Proposed Building and Land Use MNA would not meet the desired land-use requirements as they pertain to the COCs since redevelopment work would occur immediately.  Short-term Impacts to the Environment – “Green” Remediation Approaches There is little disturbance to the environment during MNA and there is a reduced volume of investigation derived wastes. Direct push technology for groundwater sampling does not result in drill cuttings or excess soil waste and related investigation derived waste. Many current groundwater sampling procedures utilize low-flow sampling equipment during monitoring to minimize purge volumes and energy consumption while producing little investigation derived waste. 5.2.2 Detailed Analysis of Alternative 2 – Combination of Excavation/Removal of Petroleum- contaminated Soils and Monitored Natural Attenuation  Overall Protection of Human Health and the Environment This alternative will remove the main source of site contamination, as determined through Site testing and analysis. However, some contamination may remain at the Site and ongoing groundwater monitoring of natural attenuation processes will ensure that any remaining contamination does not migrate offsite and will provide data on the remaining amounts of contamination over time. Transportation of hazardous materials wastes also poses a potential, but negligible, short-term risk to human health and the environment.  Ease of Implementation Two areas demonstrating the highest contamination have been generally determined to the extent possible. Nearby contractors are available to excavate this area using an excavator and they will transport the soil to the closest landfarm. Groundwater sampling using the existing monitoring well network should be completed quarterly. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 18  Cost Overall costs for this alternative will be higher since it combines both the removal of the contamination source and ongoing monitoring to aid in Site closure. Mobilization fees, sampling, and laboratory fees would incur during quarterly monitoring events. Remediation design, excavation, transportation, and treatment costs are estimated at $170,000 to $200,000 and groundwater monitoring costs are estimated at $6,000 to $10,000 per year.  Sustainability – Operations and Maintenance and Long-term Effectiveness Since the contamination source will be removed, the period of time for natural attenuation may be shortened which may lead to a reduced monitoring time frame. Since contamination data is known, institutional controls may be removed from the Site once it reaches compliance with regulations or institutional controls may even be eliminated.  Ability to Meet Proposed Building and Land Use Since contamination data may be known, institutional controls may be removed from the Site once it reaches compliance with regulations or institutional controls may even be eliminated.  Short-term Impacts to the Environment – “Green” Remediation Approaches This alternative would have significant short-term impacts due to the amount of fossil fuels being used for excavation and transportation. Additionally, the disturbance of the contaminated soils may increase the short-term environmental exposure potential. Additional fossil fuels will be burned during the quarterly monitoring events. The excavated soils will be landfarmed, which will allow for soil reuse. Direct push technology for groundwater sampling does not result in drill cuttings or excess soil waste and related investigation derived waste. Many current groundwater sampling procedures utilize low-flow sampling equipment during monitoring to minimize purge volumes and energy consumption while producing little investigation derived waste. 5.2.3 Detailed Analysis of Alternative 3 – In-situ Chemical Oxidation  Overall Protection of Human Health and the Environment This alternative would transform the soil and groundwater contaminants into less harmful chemical species.  Ease of Implementation Injection wells would need to be installed in several locations on a grid for optimum delivery of oxidants to all petroleum impacted areas. Permits may be required for the injection of an oxidizing agent into the Site groundwater.  Cost The cost of the type of oxidant used will drive the overall cost of this cleanup alternative. Mobilization fees and laboratory fees would incur during quarterly monitoring events. The cost ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 19 to implement a source area injection could range from $65,000 to $85,000 along with groundwater monitoring costs estimated at $15,000 to $20,000 per year.  Sustainability – Operations and Maintenance and Long-term Effectiveness This alternative may require institutional controls to ensure that human health is adequately protected. Quarterly monitoring will also be needed to determine the effectiveness of the chemical oxidation and to ensure that human health is adequately protected.  Ability to Meet Proposed Building and Land Use Institutional controls may be needed until remaining Site contaminant concentrations are known.  Short-term Impacts to the Environment – “Green” Remediation Approaches There is little disturbance to the environment during monitored natural attenuation and direct push technology for the installation of injection wells does not result in drill cuttings or excess soil waste and related investigation derived waste. 5.2.4 Detailed Analysis of Alternative 4 – Combination of Soil Excavation and In-situ Chemical Oxidation  Overall Protection of Human Health and the Environment This alternative will remove the main source of Site contamination, as determined through Site testing and analysis. However, some contamination may remain at the Site and the introduction of an oxidizing chemical will ensure that any remaining contamination will be transformed into less harmful chemical species. Transportation of hazardous materials wastes also poses a potential, but negligible, short-term risk to human health and the environment.  Ease of Implementation Two areas demonstrating the highest contamination have been generally determined to the extent possible. Nearby contractors are available to excavate this area using an excavator and they will transport the soil to the closest landfarm. Groundwater sampling using the existing monitoring well network should be completed quarterly.  Cost Overall costs for this alternative will be higher since it combines the removal of the contamination source coupled with in-situ chemical oxidation and ongoing monitoring to aid in Site closure. Mobilization fees, sampling, and laboratory fees would incur during quarterly monitoring events. Remediation design, excavation, transportation, and treatment costs are estimated at $170,000 to $200,000. The cost of the type of oxidant used will drive the overall cost of this cleanup alternative. Mobilization fees and laboratory fees would incur during quarterly monitoring events. The cost to implement a source area injection could range from $65,000 to $85,000 along with groundwater monitoring costs estimated at $15,000 to $20,000 per year. Groundwater monitoring costs are estimated at $6,000 to $10,000 per year. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 20  Sustainability – Operations and Maintenance and Long-term Effectiveness This alternative may require institutional controls to ensure that human health is adequately protected. Quarterly monitoring will also be needed to determine the effectiveness of the chemical oxidation and to ensure that human health is adequately protected.  Ability to Meet Proposed Building and Land Use The main contamination source will be removed from the Site. However, it is possible that some contamination will remain and institutional controls may need to be set in place to protect human health and the environment for any future land use. Monitoring would be necessary to determine when groundwater meets acceptable use criteria.  Short-term Impacts to the Environment – “Green” Remediation Approaches This alternative would have significant short-term impacts due to the amount of fossil fuels being used for excavation and transportation. Additionally, the disturbance of the contaminated soils may increase the short-term environmental exposure potential. Additional fossil fuels will be burned during the quarterly monitoring events. The excavated soils will be landfarmed, which will allow for soil reuse. Direct push technology for the installation of injection wells does not result in drill cuttings or excess soil waste and related investigation derived waste. 5.2.5 Detailed Analysis of Alternative 5 – Soil Vapor Extraction and Air Sparging  Overall Protection of Human Health and the Environment Due to the shallow depth to groundwater and soil type, SVE with air sparging will not effectively remediate the site contaminants and may even facilitate off-site contaminant migration.  Ease of Implementation An SVE and air sparging system can be left onsite without disturbing the current or future Site use. A direct push drill rig to will be necessary to complete the construction of the air sparging and SVE wells. However, this option requires detailed pilot testing and monitoring to ensure vapor control and limit contamination migration.  Cost Overall costs are estimated at $30,000 to $50,000 to implement along with $50,000 to $60,000 per year in O&M and monitoring.  Sustainability – Operations and Maintenance and Long-term Effectiveness Quarterly monitoring will be needed to determine the effectiveness of the SVE and air sparge system and to ensure that human health is adequately protected. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 21  Ability to Meet Proposed Building and Land Use Institutional controls may need to be set in place to protect human health and the environment for any future land use. Monitoring would be necessary to determine when groundwater meets acceptable use criteria.  Short-term Impacts to the Environment – “Green” Remediation Approaches Fossil fuels will be burned during the installation of the injection wells and during the quarterly monitoring events. Direct push technology for the installation of injection wells does not result in drill cuttings or excess soil waste and related investigation derived waste. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 22 Section 6.0 Comparative Analysis of Clean-up Alternatives 6.1 Alternative Ranking Criteria Table 11 compares the analysis of the six proposed alternatives against the evaluation criteria. Alternatives with higher scores are considered better options for the owners. Rankings were made on a scale of through with:  1 = Low Success,  2 = Moderate or Average Success, and  3 = High Success. Table 11. Comparative Analysis of Clean-up Alternatives Cleanup Alternative Overall Protection of Human Health and the Environment Ease of Implementation Cost-Effective Approach Toward Remediation Sustainability - O&M and Long-term Effectiveness Ability to Meet Proposed Land Use “Green” Remediation Approach Total Score 1. Monitored natural attenuation. 2 3 2 2 1 3 13 2. Combination of soil excavation/removal and monitored natural attenuation. 2 3 3 2 1 3 14 3. In-situ chemical oxidation. 2 2 1 3 3 3 14 4. Combination of soil excavation/removal and in-situ chemical oxidation. 3 2 2 3 3 3 16 5. Soil vapor extraction with air sparging. 1 2 2 2 2 3 10 5. No-Action. 1 3 3 1 1 1 10 Notes: (1=Low Success, 2=Medium Success, 3=High Success) (For Cost: 1=High Cost, 2=Medium Cost, 3=Low Cost) 6.2 Summary Alternatives 1 through 4 were similarly ranked yet they each score differently in significant areas. Alternatives 3 and 4 have a higher overall long-term effectiveness but are much more costly, while alternative 1 has lower long-term effectiveness. Alternative 5 appears to be the ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 23 least effective alternative. Alternative 4, a combination of soil excavation/removal and in-situ chemical oxidation, is the most cost effective alternative in combination with having a high likelihood of success, allowing certainty to redevelopment construction schedules and protection of human health and the environment. ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 24 Section 7.0 References and Resources Used American Society for Testing and Materials (ASTM), 2005. D-6282-98, Standard Guide for Direct Push Soil Sampling for Environmental Site Characterizations. ASTM, 2006. D-5314-92, Standard Guide for Soil Gas Monitoring in the Vadose Zone. ASTM, 2007. D-4448-01, Standard Guide for Sampling Ground-Water Monitoring Wells. Idaho Department of Environmental Quality (IDEQ), 2004. Risk Evaluation Manual (REM). 1410 North Hilton, Boise, Idaho 83706, April 2004. IDEQ, 2012. Risk Evaluation Manual for Petroleum Releases (Petro REM). 1410 North Hilton, Boise, Idaho 83706, July 2012. Sharpe, Ted, 2008. Letter to Gayle Westoff, IDEQ. October 6. Sharpe, Ted, 2009. Letter to Gayle Westoff, IDEQ. September 14. TerraGraphics Environmental Engineering, Inc. (TerraGraphics), 2011. Phase I Environmental Site Assessment Report: 1102 South Main Street Moscow, Idaho. Prepared for the city of Moscow, October. TerraGraphics, 2013. Quality Assurance Project Plan (QAPP): 1102 South Main Street Moscow, Idaho Phase II Environmental Site Assessment – Addendum II. Prepared for the City of Moscow, August. TerraGraphics and STRATA, 2012. Quality Assurance Project Plan (QAPP): 1102 South Main Street Moscow, Idaho Phase II Environmental Site Assessment. Prepared for the city of Moscow, February. TerraGraphics and STRATA, 2013. Quality Assurance Project Plan (QAPP): 1102 South Main Street Moscow, Idaho Phase II Environmental Site Assessment – Addendum I. Prepared for the City of Moscow, March. TerraGraphics Environmental Engineering, Inc. (TerraGraphics), 2014. Phase II Environmental Site Assessment Report: 1102 South Main Street Moscow, Idaho. Prepared for the city of Moscow, October. U.S. Environmental Protection Agency (USEPA), 1992. Method 8011: 1,2-Dibromoethane and 1,2-Dibromo-3-Chloropropane by Microextraction and Gas Chromotography, Revision 0. USEPA, 1994. Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma – Mass Spectrometry, Revision 5.4. USEPA, 1996a. Method 5035: Closed-System Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples, December, Revision 0. USEPA, 1996b. Method 8260B: Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS), Revision 2. USEPA, 1996c. Method 8270C: Semivolatile Organic compounds by gas Chromatography/Mass Spectrometry (GC/MS), Revision 3. USEPA, 1999a. Method TO-15: Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air Second Edition Compendium Method TO-15 ---PAGE BREAK--- ABCA for the Former Sharpe Oil Site in Moscow, Idaho 25 Determination of Volatile Organic Compounds in Air Collected in Specially-Prepared Canisters and Analyzed by Gas Chromatography/Mass Spectrometry (GC/MS). EPA/625/R-96/010b, January. USEPA, 1999b. Method TO-17: Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air Second Edition Compendium Method TO-17 Determination of Volatile Organic Compounds in Ambient Air Using Active Sampling Onto Sorbent Tubes. EPA/625/R-96/010b, January. USEPA, 2004. Standard Operating Procedure for Installation of Sub-Slab Vapor Probes and Sampling Using USEPA Method TO-15 to Support Vapor Intrusion Investigations. USEPA, 2007a. Method 6020A: Inductively Couple Plasma-Mass Spectrometry, Revision 1. USEPA, 2007b. Method 8270D: Semivolatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS). USEPA, 2012. Regional Screening Levels for Chemical Contaminants at Superfund Sites. http://www.epa.gov/region09/superfund/prg/ Accessed in 2013. ---PAGE BREAK--- ---PAGE BREAK--- FIGURE 2: ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- ---PAGE BREAK--- BH-1 16 ft bgs BH-2 5 ft bgs BH-2 15 ft bgs BH-3 15 ft bgs BH-4 13 ft bgs BH-5 12 ft bgs BH-6 17.5 ft bg BH-7 14 ft bgs BH-8 10 ft bgs BH-8 14 ft bgs BH-9 14 ft bgs BH-10 16.5 ft bgs BH-11 17 ft bgs BH-12 13 ft bgs BH-12 15 ft bgs BH-13 13.5 ft bgs BH-14 18.5 ft bgs BH-15 14 ft bgs BH-16 11.5 ft bgs BH-17 14.5 ft bgs BH-18 14.5 ft bgs BH-19 13.5 ft bgs BH-20 11 ft bgs BH-21 14.5 ft bgs BH-22 13.5 ft bgs BH-23 15 ft bgs BH-24 14 ft bgs Vapor Intrusion Direct Contact GW Protection IDTLs (mg/kg) Critical Pathway Critical Receptor VOCs 1,2-Dibromoethane <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.001 <0.001 <0.0001 <0.0001 <0.0001 <0.001 <0.001 <0.1 <0.005 <0.005 <0.005 <1 <0.002 <0.001 <0.001 <0.1 <0.5 <0.04 <0.001 <0.001 <1 0.001 0.27 0.00014 1,2-Dichloroethane <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.0001 <0.0001 <0.001 <0.001 <0.001 <0.005 <0.005 <0.5 <0.025 <0.025 <0.025 <5 <0.01 <0.005 <0.005 <0.5 <2.5 <0.2 <0.005 <0.005 <5 0.02 3.7 0.013 Benzene <0.001 0.0503 0.560 <0.001 0.0196 0.460 0.829 0.310 <0.001 <0.001 <0.001 0.00839 0.0239 0.788 0.0772 0.0716 3.33 19.9 0.0100 0.0793 <0.005 1.12 4.31 0.241 <0.005 0.129 16.3 0.08 8.3 0.025 <0.001 0.629 1.12 <0.001 <0.001 6.97 0.908 5.61 <0.001 <0.001 <0.001 0.0354 0.123 18.6 3.19 2.76 3.18 55.1 0.295 0.0161 <0.005 2.20 45.0 37.4 <0.005 0.00708 33.6 0.25 39 7.4 Total Xylene <0.003 1.64 0.1740 0.00607 <0.003 37.6 4.80 19.48 <0.003 <0.003 <0.003 0.0351 0.0197 133.4 3.885 3.377 4.40 294.3 0.379 0.04343 <0.01 12.41 343.7 222.4 0.0127 0.00668 180 27 8500 91 Methyl-tert-butyl ether (MTBE) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.005 <0.005 <0.5 <0.025 <0.025 <0.025 <5 <0.01 <0.005 <0.005 <0.5 <2.5 <0.2 <0.005 <0.005 <5 2.4 340 0.08 Naphthalene <0.001 1.69 1.08 0.0127 <0.001 2.50 0.314 1.62 <0.001 <0.001 <0.001 0.167 0.226 13.6 2.42 1.34 4.47 21.5 0.319 0.00632 <0.005 0.857 15.7 14.0 0.00965 <0.005 9.02 0.12 44 9.2 Toluene <0.001 <0.001 0.0472 <0.001 <0.001 15.8 1.97 0.307 <0.001 <0.001 <0.001 <0.005 <0.005 0.923 0.0426 0.0410 0.897 38.0 <0.01 0.0133 <0.005 5.17 102 8.91 <0.005 0.00502 125 1300 62000 6.6 PAHs <0.01 4.22 5.47 <0.01 <0.01 4.27 0.357 5.02 <0.01 <0.01 <0.01 3.36 0.435 39.2 17.9 5.43 2.89 29.7 2.42 0.0217 <0.01 10.8 11.0 8.20 0.0108 <0.01 9.32 3.31 GWP GWP Acenaphthene <0.01 0.092 0.189 <0.01 <0.01 0.031 <0.01 <0.01 <0.01 <0.01 <0.01 0.780 <0.02 0.541 0.314 0.184 0.0873 0.565 0.427 <0.01 <0.01 0.0705 0.0804 0.0383 <0.01 <0.01 0.0786 NA 37,000 200 <0.01 0.051 0.084 <0.01 <0.01 0.014 <0.01 0.196 <0.01 <0.01 <0.01 0.141 <0.02 0.264 0.207 0.125 0.0565 0.246 0.0224 <0.01 <0.01 0.0229 0.0393 0.0146 <0.01 <0.01 0.0430 78.0 GWP GWP Anthracene <0.01 0.038 0.066 <0.01 <0.01 0.020 <0.01 0.137 <0.01 <0.01 <0.01 0.110 <0.02 0.174 0.105 0.125 0.0371 0.333 2.02 <0.01 <0.01 0.0400 0.0312 0.0124 <0.01 <0.01 0.0300 NA 190,000 3,200 Benzo(ghi)perylene <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.0823 0.0281 <0.02 <0.01 <0.01 0.0779 <0.02 2.20 <0.01 <0.01 <0.02 <0.01 <0.01 <0.01 <0.01 0.0103 1,178 Surficial Soil Child Benzo[a]anthracene <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.0257 <0.02 0.0517 0.0196 0.0190 0.0369 0.0482 6.66 <0.01 <0.01 0.0273 0.0208 0.0127 <0.01 <0.01 0.0308 NA 0.19 0.09 Benzo[a]pyrene <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.0208 <0.02 <0.02 <0.01 <0.01 0.0262 <0.02 4.38 <0.01 <0.01 <0.02 <0.01 <0.01 <0.01 <0.01 <0.02 NA 0.02 2.1 Benzo[b]fluoranthene <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.0231 <0.02 <0.02 <0.01 <0.01 0.0326 <0.02 5.55 <0.01 <0.01 <0.02 <0.01 <0.01 <0.01 <0.01 <0.02 NA 0.19 0.31 Benzo[k]fluoranthene <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.02 <0.02 <0.02 <0.01 <0.01 0.0103 <0.02 1.71 <0.01 <0.01 <0.02 <0.01 <0.01 <0.01 <0.01 <0.02 NA 1.9 3.1 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.0633 <0.02 <0.02 0.0159 <0.01 0.0686 <0.02 5.44 <0.01 <0.01 <0.02 <0.01 <0.01 <0.01 <0.01 <0.02 NA 19 9.5 Dibenz[a,h]anthracene <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.02 0.0253 <0.02 <0.01 <0.01 0.0109 <0.02 0.782 <0.01 <0.01 <0.02 <0.01 <0.01 <0.01 <0.01 <0.02 0.0422 Surficial Soil Age-Adjusted Fluoranthene <0.01 <0.01 0.014 <0.01 <0.01 <0.01 <0.01 0.013 <0.01 <0.01 <0.01 0.0464 <0.02 0.0667 0.0462 0.0315 0.0479 0.0701 8.90 <0.01 <0.01 <0.02 0.0150 <0.01 <0.01 <0.01 0.0213 NA 25,000 1,400 Fluorene <0.01 0.334 0.529 <0.01 <0.01 0.078 <0.01 1.11 <0.01 <0.01 <0.01 1.16 0.0620 1.52 1.07 0.594 0.350 1.82 0.530 <0.01 <0.01 0.170 0.246 0.0627 <0.01 <0.01 0.299 NA 25,000 240 Indeno[1,2,3-cd]pyrene <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.0306 0.0277 <0.02 <0.01 <0.01 0.0307 <0.02 2.01 <0.01 <0.01 <0.02 <0.01 <0.01 <0.01 <0.01 <0.02 0.422 Surficial Soil Age-Adjusted Naphthalene <0.01 1.93 2.26 <0.01 <0.01 2.92 0.233 6.72 <0.01 <0.01 <0.01 1.16 0.141 30.4 11.7 4.17 1.32 22.0 0.802 0.0236 <0.01 9.48 10.5 7.54 <0.01 <0.01 7.14 0.12 44 9.2 Phenanthrene <0.01 0.396 0.615 <0.01 <0.01 0.139 <0.01 1.12 <0.01 <0.01 <0.01 1.15 0.105 1.65 1.67 1.25 0.628 3.57 5.36 <0.01 <0.01 0.355 0.444 0.0922 <0.01 <0.01 0.528 79.0 GWP GWP Pyrene <0.01 0.021 0.038 <0.01 <0.01 0.021 <0.01 0.027 <0.01 <0.01 <0.01 0.124 <0.02 0.178 0.139 0.133 0.0815 0.316 7.49 <0.01 <0.01 0.0415 0.0577 0.0182 <0.01 <0.01 0.0553 NA 19,000 1,000 Total Metals Lead 9.04 10.4 2.78 4.23 5.05 7.46 3.42 3.59 4.73 2.78 4.27 13.6 7.62 6.62 3.60 4.40 105 3.47 5.15 3.95 2.91 3.50 4.19 3.45 3.56 3.43 3.24 49.6 GWP GWP Notes: ft = feet bgs = below ground surface mg/kg = milligrams per kilogram GW = groundwater Volatile organic compounds (VOCs) analyzed by 8260B aromatic hydrocarbons (PAHs) analyzed by 8270C or 8270D Naphthalene analyzed by both 8260B and 8270(C or D) Lead analyzed by 6020A < = below reporting limit Highest concentrations are listed between the regular samples and the duplicate samples collected at BH-3 and BH-21. Sample concentrations in BOLD are above the Screening Levels as defined the Idaho Risk Evaluation Manual for Petroleum Releases, Table 2 (IDEQ, 2012) for VOCs and certain PAHs OR the Idaho Risk Evaluation Manual, Appendix A Initial Default Target Levels (IDEQ, 2004) for certain PAHs and metals. Petro REM concentrations in BOLD are the current screening levels specified in the Rule. m+p-Xylene and o-Xylene results were added to represent Total Xylene concentration and compared to Total Xylene Screening Level. Table 1. All Direct Push Soil Sample Analytical Results. (mg/kg) 2012 Petro REM Screening Levels (mg/kg) 2004 REM Screening Levels (mg,kg) Analyte ---PAGE BREAK--- Table 2. Soil Boring Sample Analytes Exceeding Petro REM Screening Levels or the REM IDTLs by Exposure Pathway (3 pages). Sample location Analyte Petro REM Screening Level REM (IDTL) Vapor Intrusion Direct Contact GWP Surficial Soil GWP BH-2 (5 feet bgs) Benzene X X Naphthalene X X BH-2 (15 feet bgs) Benzene X X X Naphthalene X X BH-5 (12 feet bgs) Benzene X X X Total Xylenes X Naphthalene X Toluene X X BH-6 (17.5 feet bgs) Benzene X X X Naphthalene X BH-7 (14 feet bgs) Benzene X X X Naphthalene X X BH-10 (16.5 feet bgs) Naphthalene X X Benzo[a]pyrene X BH-11 (17 feet bgs) Naphthalene X BH-12 (13 feet bgs) Benzene X X Total Xylenes X Naphthalene X ---PAGE BREAK--- Table 2. Soil Boring Sample Analytes Exceeding Petro REM Screening Levels or the REM IDTLs by Exposure Pathway (3 pages). Sample location Analyte Petro REM Screening Level REM (IDTL) Vapor Intrusion Direct Contact GWP Surficial Soil GWP BH-12 (15 feet bgs) Benzene X X Naphthalene X X BH-13 (13.5 feet bgs) Benzene X X Naphthalene X X BH-14 (18.5 feet bgs) Benzene X X Naphthalene X Benzo[a]pyrene X Total Lead X BH-15 (14 feet bgs) Benzene X X Total Xylenes X Naphthalene X Toluene X X BH-16 (11.5 feet bgs) X Naphthalene X Benzo[a]anthracene X Benzo[a]pyrene X Benzo[b]fluoranthene X Dibenz[a,h]anthracene X Indeno[1,2,3-cd]pyrene X BH-17 (14.5 feet bgs) Benzene X BH-19 (13.5 feet bgs) Benzene X X Naphthalene X X ---PAGE BREAK--- Table 2. Soil Boring Sample Analytes Exceeding Petro REM Screening Levels or the REM IDTLs by Exposure Pathway (3 pages). Sample location Analyte Petro REM Screening Level REM (IDTL) Vapor Intrusion Direct Contact GWP Surficial Soil GWP BH-20 (11 feet bgs) Benzene X X Total Xylenes X Naphthalene X Toluene X X BH-21 (14.5 feet bgs) Benzene X X Total Xylenes X Naphthalene X Toluene X X BH-23 (15 feet bgs) Benzene X BH-24 (14 feet bgs) Benzene X X Total Xylenes X Naphthalene X Toluene X X Notes: bgs = below ground surface GWP = groundwater protection IDTL = Initial Default Target Level ---PAGE BREAK--- Table 3. Groundwater Elevation Data. Well TOIC Elevation (feet amsl) April 18, 2012 May 1-2, 2013 Depth to Groundwater (feet) Groundwater Elevation (feet amsl) Depth to Groundwater (feet) Groundwater Elevation (feet amsl) MW-1 2579.20 7.98 2571.22 10.37 2568.83 MW-2 2573.93 5.43 2568.50 7.37 2566.56 MW-3 2570.88 NA NA 5.93 2564.95 MW-4 2570.85 NA NA 7.50 2563.35 MW-5 2570.80 NA NA 7.07 2563.73 MW-14 2570.91 2.10 2568.81 5.19 2565.72 MW-15 2571.33 3.19 2568.14 5.30 2566.03 Notes: TOIC = top of inside casing amsl = above mean sea level NA = not applicable because well was not installed ---PAGE BREAK--- Table 4. Field Parameter Data. Well (date) pH Conductivity (mS/cm) Temp Dissolved Oxygen (mg/L) Oxidation-Reduction Potential (mV) MW-1 (4/18/2012) 6.20 0.673 9.46 8.22 211 (5/2/2013) 6.15 0.728 10.04 5.75 229 MW-2 (4/18/2012) 6.27 0.536 9.92 1.50 131 (5/1/2013) 6.45 0.345 10.42 0.24 -63 MW-3 (4/18/2013) NA NA NA NA NA (5/1/2013) 6.44 0.519 8.72 0.82 -98 MW-4 (4/18/2013) NA NA NA NA NA (5/1/2013) 6.52 0.633 9.84 0.29 101 MW-5 (4/18/2013) NA NA NA NA NA (5/1/2013) 6.42 0.499 10.14 0.33 23 MW-14 (4/18/2012) 6.62 0.397 8.02 2.26 123 (5/1/2013) 6.80 0.392 8.38 5.64 176 MW-15 (4/18/2012) 6.36 0.410 8.78 0.36 85 (5/1/2013) 6.68 0.444 9.32 0.37 -66 Notes: mS/cm = millisiemens per centimeter ◦C = degrees Celsius mg/L = milligrams per liter mV = millivolt NA = not applicable because well was not installed ---PAGE BREAK--- 2012 2013 2012 2013 2012 2013 2012 2013 2012 2013 2012 2013 2012 2013 Vapor Intrusion Ingestion IDTLs (mg/L) Critical Pathway Critical Receptor VOCs 1,2-Dibromoethane (EDB) <0.00005 <0.00005 *<0.0025 <0.00005 NA <0.00025 NA <0.00005 NA <0.00005 <0.00005 <0.00005 <0.001 <0.00005 0.004 0.00005 1,2-Dichloroethane (EDC) <0.001 <0.001 *<0.05 <0.001 NA <0.005 NA <0.001 NA <0.001 <0.001 <0.001 <0.02 <0.005 0.03 0.005 Benzene <0.001 <0.001 1.77 0.0658 NA 1.26 NA <0.001 NA <0.001 <0.001 <0.001 0.733 0.606 0.044 0.005 <0.001 <0.001 2.09 0.392 NA 0.338 NA <0.001 NA 0.00146 <0.001 <0.001 0.632 0.604 0.05 0.700 Total Xylene <0.002 <0.002 6.23 0.368 NA 0.0877 NA <0.002 NA <0.002 <0.003 <0.002 0.900 1.067 8.7 10 Methyl-tert-butyl ether (MTBE) <0.001 <0.001 *<0.05 <0.001 NA 0.0123 NA 0.00151 NA 0.00767 <0.001 <0.001 <0.02 <0.005 6.8 0.04 Naphthalene <0.001 <0.001 0.558 0.178 NA 0.0265 NA <0.001 NA <0.001 <0.001 <0.001 0.0940 0.103 0.07 0.73 Toluene <0.001 <0.001 4.21 0.0251 NA 0.0204 NA <0.001 NA <0.001 <0.001 <0.001 <0.02 0.229 340 1 PAHs 0.000061 <0.00001 0.125 0.0287 NA 0.00822 NA 0.0000211 NA <0.00001 <0.000005 <0.00001 0.0229 0.0193 0.0417 Ingestion Risk-Based Acenaphthene <0.000005 <0.00001 0.000453 0.000246 NA 0.000101 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 0.000137 NA 2.2 <0.000005 <0.00001 0.000129 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 0.626 Ingestion Risk-Based Anthracene <0.000005 <0.00001 0.000047 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 NA 11 Benzo(ghi)perylene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 0.313 Ingestion Risk-Based Benzo[a]anthracene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 NA 0.00003 Benzo[a]pyrene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 NA 0.0002 Benzo[b]fluoranthene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 NA 0.00003 Benzo[k]fluoranthene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 NA 0.0003 <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 NA 0.003 Dibenz[a,h]anthracene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 0.00000765 Ingestion Risk-Based Fluoranthene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 NA 1.5 Fluorene <0.000005 <0.00001 0.000395 0.000277 NA 0.0000829 NA <0.00001 NA 0.0000142 <0.000005 <0.00001 0.000213 0.000158 NA 1.5 Indeno[1,2,3-cd]pyrene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA <0.00001 <0.000005 <0.00001 <0.000005 <0.00005 0.0000765 Ingestion Risk-Based Naphthalene 0.000048 <0.00001 0.552 0.131 NA 0.0268 NA 0.0000701 NA <0.00001 <0.000005 <0.00001 0.117 0.0842 0.07 0.73 Phenanthrene 0.000017 <0.00001 0.000314 0.000153 NA 0.000100 NA <0.00001 NA <0.00001 <0.000005 <0.00001 0.000128 0.0000719 0.313 Ingestion Risk-Based Pyrene <0.000005 <0.00001 <0.000005 <0.00005 NA <0.00005 NA <0.00001 NA 0.0000278 <0.000005 <0.00001 <0.000005 <0.00005 NA 1.1 Total Metals Lead <0.0001 <0.001 0.00622 <0.001 NA <0.001 NA <0.001 NA <0.001 <0.001 <0.001 <0.001 <0.001 0.0150 Ingestion MCL Notes: mg/L = milligrams per liter < = below reported detection limit * indicates Petro REM screening level is lower than reporting limit NA = not applicable, well did not exist in 2012 sampling event Highest concentration is listed between the regular sample and the duplicate sample collected at MW-2. Volatile organic compounds (VOCs) analyzed by 8260B aromatic hydrocarbons (PAHs) analyzed by 8270C or 8270D Naphthalene analyzed by both 8260B and 8270(C or D) Lead analyzed by 200.8 Sample concentrations in BOLD are above the Screening Levels as defined the Idaho Risk Evaluation Manual for Petroleum Releases, Table 1 (IDEQ, 2012) for VOCs and certain PAHs OR the Idaho Risk Evaluation Manual, Appendix A Initial Default Target Levels (IDEQ, 2004) for certain PAHs and metals. Petro REM concentrations in BOLD are the current screening levels specified in the Rule. m+p-Xylene and o-Xylene results were added to represent Total Xylene concentration and compared to Total Xylene Screening Level. 2004 REM Screening Levels 2012 Petro REM Screening Levels Analyte Table 5. All Groundwater Analytical Results. mg/L MW-1 (mg/L) MW-2 MW-14 MW-15 MW-3 MW-4 MW-5 ---PAGE BREAK--- Table 6. Groundwater Analytes Exceeding Petro REM Screening Levels by Exposure Pathway. Sample location Analyte Petro REM Screening Levels Vapor Intrusion Ingestion April 2012 MW-2 Benzene X X X X Naphthalene X Toluene X MW-15 Benzene X X X Naphthalene X May 2013 MW-2 Benzene X X X Naphthalene X MW-3 Benzene X X X MW-15 Benzene X X X Naphthalene X Note: No groundwater analytes exceed the REM IDTLs. ---PAGE BREAK--- Table 7. Soil Vapor Analytical Summary Residential Use (µg/m3). Analyte 100x USEPA Residential RSL1 Vapor Point 10x USEPA Residential RSL2 Subslab VP-1 VP-2 VP-3 VP-4 SSW 1,2-Dichloroethane 9.4 <1.3 <1.3 <4 <4.6 0.94 <1.3 Benzene 31 <1.1 1.4 360 <3.7 3.1 37 Toluene 520,000 2.0 6.8 33 10 52,000 9.7 97 <1.4 3.7 160 <5.0 9.7 38 Total Xylenes 10,000 7.3 23 439 <5.0 1,000 109 Naphthalene 7.2 7.9 5.3 4.3 <2.9* 0.72 3.2 Notes: < = less than the method reporting limit µg/m3 = micrograms per cubic meter NM = not measured *Reported to method detection limit to be below the screening limit. 1. IDEQ’s Petro REM screening levels are 100 times the USEPA regional screening levels (RSLs) for soil vapor samples for soil vapor samples collected 3 to 5 feet below ground surface (vapor point samples collected at 4 feet below ground surface). 2. RSL for subslab samples are for samples collected beneath the subslab and are 10 times the RSL. Concentrations in BOLD are above the RSL. ---PAGE BREAK--- Table 8. Soil Vapor Analytical Summary Industrial Use (µg/m3). Analyte 100x USEPA Industrial RSL1 Vapor Point 10x USEPA Industrial RSL2 Subslab VP-1 VP-2 VP-3 VP-4 SSW 1,2-Dichloroethane 47 <1.3 <1.3 <4 <4.6 4.7 <1.3 Benzene 160 <1.1 1.4 360 <3.7 16 37 Toluene 2,200,000 2.0 6.8 33 10 220,000 9.7 490 <1.4 3.7 160 <5.0 49 38 Total Xylenes 44,000 7.3 23 439 <5.0 4,400 109 Naphthalene 36 7.9 5.3 4.3 <24 3.6 3.2 Notes: < = less than the method reporting limit µg/m3 = microgram per cubic meter 1. IDEQ’s Petro REM screening levels are 100 times the regional screening levels (RSLs) for soil vapor samples collected 3 to 5 feet below ground surface (vapor point samples collected at 4 feet below ground surface). 2. RSL for subslab samples are for samples collected beneath the subslab and are 10 times the RSL. Concentrations in BOLD are above the RSLs. ---PAGE BREAK--- Table 9. Ambient Air Analytical Summary Residential Use (μg/m3). Analyte EPA Residential RSL1 1102-AA-OVEN 1102-AA-LAUNDRY Benzene 0.31 0.90 1.2 Toluene 5,200 3.1 4.2 Ethyl Benzene 0.97 0.51 0.69 m,p-xylene 100 1.8 2.4 o-xylene 100 0.62 0.84 EDC2 0.094 <0.10* <0.10* Methyl tert-butyl ether 9.4 <0.15 <0.15 Naphthalene2 0.072 <0.13* <0.13* Notes: < = less than the method reporting limit or method detection limit (as noted) µg/m3 = micrograms per cubic meter Concentrations in BOLD are above the regional screening levels (RSLs). *Method detection limit is above the RSLs. 1. RSL for ambient air samples. 2. Sample concentration reported to the method detection limit. Table 10. Ambient Air Analytical Summary Industrial Use (μg/m3). Analyte EPA Industrial RSL1 1102-AA-OVEN 1102-AA-LAUNDRY Benzene 1.6 0.90 1.2 Toluene 22,000 3.1 4.2 Ethyl Benzene 4.9 0.51 0.69 m,p-xylene 440 1.8 2.4 o-xylene 440 0.62 0.84 EDC2 0.47 <0.10 <0.10 Methyl tert-butyl ether 47 <0.15 <0.15 Naphthalene2 0.36 <0.13 <0.13 Notes: < = less than the method reporting limit or method detection limit (as noted) µg/m3 = micrograms per cubic meter 1. Regional screening levels (RSLs) for ambient air samples. 2. Concentration reported to the method detection limit.