RAP Executive Summary ID No.: VCP ID No. 2076

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3 RAP Executive Summary ID No.: VCP ID No Report Date: March 2012 Use this worksheet to summarize the report. Be sure to complete and submit the Checklist for Report Completeness. Attach a chronology of activities associated with the affected property. Briefly describe the affected property and PCLE zones, the conclusions from the assessment activities, identify any affected or threatened receptors, and describe any other major considerations taken into account when developing this response action plan. If any portion of the response action is necessitated due to an aesthetic or nuisance condition, identify the nature of that condition and identify that portion of the response action proposed to address it. If any media that contains a PCLE zone is not addressed in this RAP, provide justification. The site is a tract of land consisting of 2.43-acres. The site is currently undeveloped but is scheduled for development as part of a medical campus. Past uses of the site have included a church, a health care facility, a warehouse and truck yard, and solvent facility. The concerns identified at the subject property included historical operations of a tank farm associated with the solvent facility and petroleum storage tank (PST) systems associated with the former warehouse and truck yard. Concentrations of chemicals of concern (COCs) exceeding the Tier 1 Residential ingestion protective concentration levels (PCLs) have been identified in the soil and groundwater at the site. The COCs in soil and groundwater have resulted from historical operations at the property. The COCs identified at the subject property include motor fuel constituents such as benzene and the chlorinated solvent tetrachloroethylene and its degradation products. The operational history of the facilities is unknown and it is not possible to identify a specific release(s) or volume of material that has resulted in the affected media. The University of Texas MD Anderson Cancer Center (MD Anderson) is pursuing the regulatory closure of affected media at the Almeda Central Development property through the Voluntary Cleanup Program (VCP) of the Texas Commission on Environmental Quality (TCEQ). A Municipal Setting Designation (MSD) was selected as part of the remedy to address the affected groundwater at the site. The subject property is part of an area that is scheduled for redevelopment to consolidate support functions for clinical and research campuses. Construction activities are planned for the area with soil and groundwater zones containing elevated concentrations of COCs. The project includes construction of a public roadway, a wastewater line, storm water lines, and a water line within the Hepburn Street right-of-way. Although the concentrations of COCs do not exceed the respective Tier 1 and Tier 2 Critical PCLs with a MSD, treatment of the saturated soil and groundwater COC zones will be conducted using in-situ treatment/chemical oxidation (ISCO) to facilitate construction. Treatment of the saturated soil and groundwater COC zones combined with utility design upgrades will also mitigate potential future COC migration at the site. The areas of saturated soil and groundwater treatment are illustrated on Figures 1A-i and 1A-ii. The saturated soil and groundwater will be remediated to meet the Texas Risk Reduction Program (TRRP) non-ingestion Tier 1 Protective Concentration Levels (PCLs). The saturated soil and groundwater COC zones at the site are briefly summarized below. Saturated Soil COC Zone: Historical operations on the site apparently resulted in soils containing COCs including the chlorinated solvent tetrachloroethylene and its degradation products trichloroethene, and cis-1,2- dichloroethene. The soil COC zone of concern (please see Figure 1A-i) is encountered in the saturated zone at depths between 17 and 21 feet below ground surface (bgs) in the area of soil boring SB-8 (Saturated Soil). The Saturate Soil zone to be treated covers approximately 1,600 square feet. Groundwater COC Zone: Historical operations apparently resulted in groundwater containing COCs. The primary COC is vinyl chloride which is above the Tier 1 non-ingestion PCL with a MSD but below the Tier 2 noningestion PCL. Other COCs below the Tier 1 non-ingestion PCL with a MSD identified in groundwater included the motor fuel constituents benzene, ethylbenzene, toluene, and xylenes, the chlorinated solvent tetrachloroethylene and its degradation products trichloroethene, cis-1,2- dichloroethene, trans-1,2-dichloroethene, and vinyl chloride, and the chlorinated solvent 1,1- dichloroethene. The area of COCs in groundwater (please see Figure 1A-ii) is located in the general vicinity of monitor well MW-2. The aerial extent of the groundwater to be treated is TCEQ-10326/RAP February

4 RAP Executive Summary ID No.: VCP ID No Report Date: March 2012 approximately 25,000 square feet and is encountered at a depth of approximately 16 feet. Soil assessment activities delineated the horizontal and vertical extent of the COCs in soils associated with historical operations to the residential assessment level. Groundwater assessment activities delineated the extent of the COCs in groundwater associated with historical operations to the residential assessment level. The major considerations taken into account during the development of the response action and Interim Response Action Plan (RAP) included the types of COCs, COC concentrations, and the site characteristics. The saturated soil COCs are volatile organic compounds (VOCs) within the saturated zone at depths between 17 and 21-feet bgs. In-situ chemical oxidation (ISCO) will be used to reduce COC mass in the Saturated Soil COC Zone to the Tier 1 Critical PCLs with a MSD. Hydrogen peroxide and the iron catalyst ferrous sulfate will be injected through a high pressure lance spaced on a grid pattern to effectively treat the saturated soil area. The ISCO technology will result in permanent mass destruction of chlorinated hydrocarbons in the Saturated Soil COC Zone. The major considerations taken into account during development of the response actions for the COCs in groundwater are also the types and concentrations of COCs and the site characteristics. An ordinance restricting the use of shallow groundwater at the site has been adopted and a MSD will be obtained for the site. There are no documented current uses of the groundwater from the shallow affected aquifer therefore there is no potential exposure to the affected groundwater through ingestion in the area. There are no surface waters in proximity to the site therefore there are no groundwater discharges to surface water. The average depth to the affected shallow aquifer is approximately 16-feet below ground surface (bgs), therefore, there is no potential for direct human exposure or construction worker exposure. Three soil ISCO treatments will be conducted. Verification soil samples will be collected following each of the soil treatments to document changes in COC concentrations. The analytical results of the verification may be used to modify subsequent treatment events. Groundwater verification samples will be collected following the groundwater treatment event. The verification samples will be used to document the changes in COC concentrations. Four groundwater monitoring events may also be conducted to evaluate the effectiveness of the groundwater. No affected or threatened receptors were identified on or near the site. The MSD along with the ISCO treatment at the site appears to be an appropriate response action for the COCs in saturated soil and groundwater at VCP site What is the selected remedy standard for this affected property? X A B List all media that contains a PCLE zone and specify the proposed response action for each media. Indicate the type of removal, decontamination, physical control and/or institutional control action that is proposed. Media COCs 1 Removal Decontamination Control NA Physical Control Modified Groundwater Response Objective 2 PMZ WCU TI 1 Specify either a specific COC or, if the response action is the same for all COCs in one type, specify the type of COC (for example, VOCs, SVOCs, metals). 2 If a modified groundwater response objective is proposed, check the type(s) of proposed modifications. TCEQ-10326/RAP February

5 RAP Executive Summary ID No.: VCP ID No Report Date: March 2012 Is there a media that contains a PCLE zone that is not addressed in this RAP? yes X no If yes, provide justification for not addressing the PCLE zone in this RAP. On-site land use: X Residential Commercial/Industrial Off-site land use: X Residential X Commercial/Industrial (check all that apply) Is this a re-submittal or revision of a previous RAP? Yes X No If yes, explain why the RAP is being revised or resubmitted. Were all the appropriate notifications made in accordance with ? X Yes No If no, explain why notifications were not made: TCEQ-10326/RAP February

6 CHRONOLOGY

7 Chronology Almeda Central Development Property 7405 Almeda Road Houston, Texas Date March 2012 March 2012 November 2011 October 2011 March 2011 December 2010 August 2010 October 2009 April 2009 January 2009 October 2008 April 2008 October 2007 June 2007 April 2007 March 2007 February 2007 Activity Interim RAP submitted to the TCEQ. A Resolution of Support for the MSD was passed by the City of Southside Place, Texas. A Resolution of Support for the MSD was passed by the City of Bellaire, Texas. A Resolution of Support for the MSD was passed by the City of West University Place, Texas. Bench Scale testing for ISCO treatment was conducted at the site. A MSD Ordinance for the groundwater at the site was passed by the City of Houston, Texas. APAR Addendum submitted to the TCEQ. A groundwater monitoring event was conducted at the site. A groundwater monitoring event was conducted at the site. A groundwater monitoring event was conducted at the site. A groundwater monitoring event was conducted at the site. APAR submitted to the TCEQ. Additional subsurface investigation activities were conducted by Halff to further delineate the affected soil and groundwater at the site. VCP application package submitted to the TCEQ VCP. Additional subsurface investigation activities were conducted by ENSR Corporation to delineate affected soil and to determine if groundwater was affected by COCs from historical operations. ENSR Corporation conducted an initial Phase II Environmental Site Assessment at the property to determine if media at the site had been affected from historical on- and off-site operations identified during the Phase I Environmental Site Assessment. ENSR Corporation conducted a Phase I Environmental Site Assessment on the subject property.

8 Checklist for Report Completeness ID No.: VCP ID No Report Date: March 2012 Use this checklist to determine the portions of the form that must be submitted for this report. Answer all questions by checking Yes or No. If the answer is Yes include that portion of the report. If the answer is No, do not complete or submit that portion of the report. All form contents that are marked "Required" must be submitted. Form contents marked with an asterisk (*) are not included in the blank form and are to be provided by the person. Report Contents Required Cover Page Required Required Executive Summary Checklist for Report Completeness No Have new data been collected that was not previously submitted? Required Worksheet 1.0 Response Action Objectives Yes Attachment 1A* Maps and Cross Sections Attachment 1B* Graphs of Concentration versus Time Required Worksheet 2.0 Response Action Design Required Attachment 2A* Response Action Diagrams and Component/Equipment Descriptions Required Attachment 2B* Proposed Well Design No No Is an ecological services analysis or compensatory restoration plan part of the proposed response action? Is a plume management zone proposed as part of the response action? Yes Attachment 2C* ESA and Compensatory Restoration Plan Yes Worksheet 2.1 Plume Management Zone No Is a waste control unit proposed as part of the response action? Attachment 2D* Plume Management Zone Map Attachment 2E* Attenuation Action Levels Determination Yes Worksheet 2.2 Waste Control Unit No Is a technical impracticability area proposed as part of the response action? Attachment 2F* Map of Waste Control Unit Yes Worksheet 2.3 Technical Impracticability Attachment 2G* Map of Technical Impracticability Area TCEQ-10326/RAP February

9 Checklist for Report Completeness ID No.: VCP ID No Report Date: March 2012 Report Contents No Is the response action a remedy standard B? Yes Worksheet 2.4 Institutional Controls Required Worksheet 3.0 Performance Measures and Potential Problems Required Worksheet 3.1 Monitoring and Sampling Required Attachment 3A* Map of Monitoring and Sampling Points Required Worksheet 3.2 Operation and Maintenance Required Worksheet 4.0 Confirmation Sampling Plan Required Attachment 4A* Map of Confirmation Sampling Points No Is the response action a Remedy Standard B? Yes Worksheet 5.0 Post Response Action Care Attachment 5A* Map of PRAC Monitoring and Sampling Points Attachment 5B* PRAC Costs No Does the person, who is a small business, desire to modify the financial assurance requirement? Yes Attachment 5C* Small Business Affidavit Required Worksheet 6.0 Implementation Schedule No Was any data collected that was not previously reported? Required Appendix 1* References Yes Appendix 2* Data Tables and Boring Logs No Were any studies or tests conducted? Yes Appendix 3* Studies and Tests Documentation No Is the response action a Remedy Standard B? Yes Appendix 4* Proposed Institutional Controls No No No No Are any institutional controls proposed/required on property not owned by the person? Are any of the sample collection or handling procedures different from those reporting in the APAR or other previously submitted report? Are statistics or geostatistics proposed to be used as part of the response action? Was approval received from the TCEQ regarding the use of different rules to address a media? Yes Appendix 5* Landowner Concurrence Yes Appendix 6* Sampling Procedures Yes Appendix 7* Statistical Methodology Yes Appendix 8* Split Media Approval Form contents marked with an asterisk (*) are not included in the blank form. TCEQ-10326/RAP February

10 Response Action Objectives Associated Information: Attachment 1A, 1B RAP Worksheet 1.0 ID No.: VCP ID No, 2076 Page of Report Date: March 2012 Use this worksheet to describe the objectives for the response action in each media. Response Action Objectives List the environmental media to which this applies Groundwater and Saturated Soil Repeat this section for each medium that has a different response action objective. State the property-specific response objectives for the PCLE zone in each media in the context of the response objectives set forth in or as applicable. Explain how the response action is appropriate based on the hydrogeologic characteristics, COC characteristics, and potential unprotective conditions that could continue or result during the remedial period. An area of groundwater with vinyl chloride concentrations that are below the Tier 2 Residential Critical PCL but above the Tier 1 Residential PCL with a MSD exists within the groundwater-bearing unit at the subject property. An area of elevated COCs was identified within the saturated soil zone at the site. The response objective is to pursue a MSD and a Remedy Standard A for the saturated soil and groundwater at the site (See Figure 1A-i and 1A-ii). The subject property is part of an area that is scheduled for redevelopment to consolidate support functions for clinical and research functions. Construction activities are planned for the area with soil and groundwater zones containing elevated concentrations of COCs. The project includes construction of a public roadway, a wastewater line, storm water lines, and a water line within the Hepburn Street right-of-way. Although the concentrations of COCs do not exceed the respective Tier 1 and Tier 2 Critical PCLs with a MSD, treatment of the saturated soil and groundwater COC zones will be conducted using in-situ treatment/chemical oxidation (ISCO) to facilitate construction. Treatment of the Saturated Soil and Groundwater COC Zones combined with utility design upgrades will also mitigate potential future COC migration at the site. ISCO treatment of the saturated soil and groundwater will be conducted to achieve Tier 1 Residential Non-Ingestion PCL concentrations of vinyl chloride in the groundwater and to reduce COC mass in the area of saturated soil. A Remedy Standard A will be achieved without the use of institutional controls and post closure care. The response objectives for the subject property are detailed below. Source Control: The commercial business operations that previously occupied the site have been demolished and removed from the site. Therefore the primary sources of COCs are no longer present at the site. There is no evidence of NAPLs at the site. Based upon the site investigation data, the concentrations of COCs in soil do not exceed the Critical PCLs established for the site. However, ISCO treatment will be utilized in soils below the static water level in the vicinity of soil boring SB-8 to reduce contaminant mass contributing to the groundwater at the site. The ISCO treatment will be conducted for the reduction of the concentrations of COCs to the Tier 1 Air GW-Soil Inh-V PCL Human Health: The response action under Remedy Standard A will be to obtain a MSD and treat the groundwater to achieve a Tier 1 Residential PCL for vinyl chloride such that humans will not be exposed to concentrations of COCs in excess of the critical human health PCLs with a MSD at the prescribed points of exposure (POEs) for the environmental media, in accordance with 30 TAC and will result in permanent risk reduction. Ecological Receptors: There are no affected or threatened ecological receptors in close proximity to the Groundwater and Saturated Soil COC Zones. Exposure of ecological receptors to concentrations of COCs in the exposure medium in excess of the ecological PCLs at the POEs is not a concern. Groundwater: Concentrations of vinyl chloride below the non-ingestion Tier 2 Residential PCL but above the non-ingestion Tier 1 Residential PCL were identified in groundwater at the site. ISCO treatment of the groundwater (and Saturated Soil COC Zone) will be used to achieve Tier 1 Residential PCL concentrations of vinyl chloride at the site. The hydrogeologic setting consists of a single water-bearing unit overlying stiff, silty clay which extended from approximately 37-feet to at least 50-feet bgs. The underlying clay with corresponding low hydraulic conductivity and permeability, should inhibit the vertical migration of COCs. The water-bearing unit is overlain by approximately 16 to 22-feet of clay soils. The TCEQ-10326/RAP February

11 Response Action Objectives Associated Information: Attachment 1A, 1B RAP Worksheet 1.0 ID No.: VCP ID No, 2076 Page of Report Date: March 2012 hydrogeologic characteristics (flow direction and gradient) at the site have been consistent throughout the monitoring period. The ISCO treatment approach will be conducted for the reduction of the concentrations of COCs to the critical groundwater Tier 1 PCLs with a MSD established for the site. Potential Unprotective Conditions: A MSD will be obtained for the site which will prevent groundwater use. The ISCO treatment will reduce contaminant mass in groundwater and saturated soil and facilitate future construction in the area. The ISCO treatment combined with utility design modifications will mitigate potential future migration of COCs beyond the existing boundary of the groundwater COC zone. The depth to the groundwater-bearing unit at the site ranges between 16 and 17-feet bgs which will prevent direct human contact. Furthermore, the concentrations of COCs in groundwater are below the Tier 2 Residential Air GW Inh-V PCLs with a MSD. The ISCO treatment will further reduce the concentrations of COCs in the groundwater. Based on the data collected, the COC plume appears to be stable. The COCs were defined to the Residential Assessment Level (RAL). There should be no potential unprotective conditions. Explain how the COCs will be handled, treated, disposed, or transferred to another media and document that the response action will not result in any additional potential exposure conditions due to response action activities. The ISCO approach will be an in-situ method of reducing the concentrations of COCs in saturated soil and vinyl chloride in groundwater to below the Tier 1 Residential PCLs with a MSD. The use of the in-situ method will alleviate handling, treatment, or transfer of the COCs to another media. The average depth to the groundwater-bearing unit ranges from approximately 16 to 17-feet bgs. Four additional groundwater sampling events are anticipated at the site to evaluate the effectiveness of the treatment. The monitor well purging and sampling will be conducted using low-flow techniques, therefore there should be minimal quantities of water removed from the wells. The purgeate will be stored in drums, in a secure area, for proper disposal at an approved facility. No potential exposure conditions should exist at the site. With the primary source of COCs removed from the site, ISCO treatment should further reduce COC concentrations to levels that are protective of human health and the environment within a reasonable time frame through chemical processes. The result of the ISCO process should be the reduction of COC concentrations at the POE. The ISCO response action should not result in any additional potential exposure conditions at the site. State the proposed reasonable time frame and provide the justification for that time frame in the context of any potential for unprotective exposures to exist or develop, COC characteristics, hydrogeologic and affected property characteristics. If the reasonable time frame is different for the different affected media or for particular tracts of land, be sure to discuss that. Provide how the proposed response action will meet the objectives in a reasonable timeframe. A MSD will be obtained for the site. The COC concentrations in soil and groundwater are below the respective Critical Residential PCLs with a MSD established for the site. ISCO treatment will be used to further reduce the COC concentrations and achieve Tier 1 Residential PCLs with a MSD for COCs. The effectiveness of the treatment of the COCs in saturated soil and groundwater will be verified through sampling and laboratory analysis upon completion of ISCO treatment. Soil Response Action Objectives When using removal and/or decontamination with controls or controls only, demonstrate how that physical control or combination of measures will reliably contain COCs within and/or derived from the surface soil and subsurface soil PCLE zone materials over time. NA TCEQ-10326/RAP February

12 Response Action Objectives Associated Information: Attachment 1A, 1B RAP Worksheet 1.0 ID No.: VCP ID No, 2076 Page of Report Date: March 2012 Explain how the removal or decontamination action will reduce the concentration of COCs to the critical surface soil and subsurface soil PCL throughout the soil PCLE zone and prevent COC concentrations above the critical soil PCLs from migrating beyond the existing boundary of the soil PCLE zone. With a MSD for the site, COC concentrations are below the Critical Non-Ingestion Residential PCLs for surface and subsurface soils. As noted previously, the ISCO treatment will be used to further reduce the concentrations of COCs in the saturated soils between 17 and 21-feet in the vicinity of soil boring SB-8. The reduction of COC concentrations will prevent the migration of COCs from the saturated soil into the groundwater. TCEQ-10326/RAP February

13 Response Action Objectives Associated Information: Attachment 1A, 1B RAP Worksheet 1.0 ID No.: VCP ID No, 2076 Page of Report Date: March 2012 Groundwater Response Action Objectives Name of groundwater-bearing unit to which this information Beaumont Formation applies Repeat this section for each groundwater-bearing unit for which a different response action is proposed. Groundwater classification 1 X 2 3 Is a modified groundwater response action being proposed for any part of the groundwater PCLE zone ( (f)(2), (3), or (4))? Yes X No If yes, does the affected property meet the qualifying criteria for a modified groundwater response action using a waste control unit, plume management zone, or technical impracticability? Yes No If yes, complete the appropriate portions of this report. If no to either question, complete the following: Explain how the removal or decontamination action will reduce the concentration of COCs to the critical groundwater PCL throughout the groundwater PCLE zone and prevent COC concentrations above the critical groundwater PCL from migrating beyond the existing boundary of the groundwater PCLE zone. The commercial businesses that previously occupied the site have been demolished and removed. Therefore, the primary sources of COCs are no longer present. The COC concentrations in the soil are below the critical PCLs with a MSD established for the site, therefore, there is no secondary source or soil PCLE zone. An area of soil in the vicinity of soil boring SB-8, within the saturated zone, contained elevated concentrations of COCs. ISCO treatments of deeper soils (17 to 21-ft.) will be conducted in the deeper soils to reduce the concentrations of COCs. There should be no migration of COCs above the critical PCLs to the groundwater-bearing unit. A MSD will be obtained for the site. With a MSD, the COC concentrations in groundwater are below the Tier 1 critical PCLs established for the site with the exception of vinyl chloride which is below the Tier 2 critical PCL. In addition, an ISCO treatment approach will be used for the groundwater at the site. With the source removed, the ISCO treatment should further reduce the contaminant mass or reduce the concentrations of the COCs through chemical processes and reduce vinyl chloride concentrations to below the Tier 1 Critical PCL. The reduction of mass or COC concentrations should further reduce the potential for COC migration. Explain how the response action will prevent COCs from migrating to air at concentrations above the PCLs for air if the groundwater-to-air PCLs ( Air GW Inh-V ) is exceeded. The COC concentrations in the groundwater are below the Tier 2 Air GW Inh-V PCLs. However, the ISCO treatment will further reduce concentrations of COCs in the groundwater. The Saturated Soil COC Zone will be treated using ISCO to reduce COC mass and the potential for COC migration. There should be no COC migration to the air from soil or groundwater. Explain how the response action will prevent COCs from migrating to surface water at concentrations above the PCLs for groundwater discharges to surface water if surface water is a factor. There are no surface water bodies at the site. The nearest surface water body to the site is Bray s Bayou and is located approximately 3,000-feet to the northwest of the subject property. The COCs in the groundwater have been defined to the residential assessment levels. Surface water discharge is not a factor at the subject property. Explain how the response action will prevent human and ecological receptor exposure to the groundwater PCLE zone. The COCs in groundwater are defined to the Critical PCLs. The average depth to the water-bearing unit TCEQ-10326/RAP February

14 Response Action Objectives Associated Information: Attachment 1A, 1B RAP Worksheet 1.0 ID No.: VCP ID No, 2076 Page of Report Date: March 2012 is approximately 16-feet bgs and is overlain by approximately 16 to 22-feet of low permeability clays. The depth to the water-bearing unit and the overlying clays prevent direct human exposure to the COCs. The COC concentrations in groundwater are also below the groundwater to air inhalation PCL. A MSD will be obtained for the site which will restrict use of groundwater at the site and prevent potential exposure to the COCs in the groundwater. In addition, the response action will reduce the concentrations of the COCs in saturated soil and groundwater and prevent the migration of COCs beyond the existing extent of the COCs. There are no ecological receptors located on or adjacent to the subject property. The response action will prevent the migration of COCs beyond the existing extent of COCs, therefore there is no potential for exposure of ecological receptors. Using an ISCO treatment approach, the COC concentrations in the saturated soil and groundwater, which are below the Critical PCLs established for the site, will be further reduced below the Tier 1 critical human health non-ingestion PCLs for groundwater, resulting in a permanent risk reduction. TCEQ-10326/RAP February

15 ATTACHMENT 1A MAPS AND CROSS-SECTIONS

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18 The most current COC concentration maps, parameter maps, groundwater gradient maps and cross sections are presented in the Affected Property Assessment Report.

19 ATTACHMENT 1B GRAPHS OF CONCENTRATION VERSUS TIME

20 Sampling of environmental media will be performed upon completion of ISCO treatment to verify the effectiveness of the response action. Development of concentration versus time graphs is not anticipated.

21 Response Action Design Associated Information: Attachment 2A, 2B, 2C Response Action Design RAP Worksheet 2.0 ID No.: VCP ID No Page of Report Date: March 2012 Use this worksheet to provide detailed descriptions of the response action. Attach design and layout drawings and equipment specifications in Attachment 2A. Media: Saturated Soil and Groundwater List all media to which this information applies. If the response action is different for another media, complete a separate worksheet. Provide a detailed description of the response action. Describe the removal action, decontamination, treatment system(s), and/or physical or institutional control actions that are proposed for each media and discuss the reasons for choosing the response action(s). Identify and describe any ecological services analysis and compensatory restoration plan that will be utilized (if so, include the complete ESA and compensatory restoration plan in Attachment 2C). A MSD will be obtained for the site. The COC concentrations in groundwater are below the Tier 1 Residential PCLs with a MSD except for vinyl chloride, which is below the Tier 2 Residential PCL with a MSD. To facilitate redevelopment of the site, the anticipated response action for the groundwater is the reduction of vinyl chloride concentrations using an ISCO treatment approach and the MSD to restrict the use of groundwater at the site. The anticipated response action for saturated soil is the reduction of tetrachloroethylene concentrations using an ISCO treatment approach. The ISCO approach is being implemented based on the types and concentrations of the COCs identified at the site, the hydrogeologic characteristics of the site, and the ability to treat the shallow aquifer in-situ. The ISCO treatment should reduce the mass or concentration of the COC through chemical processes. The use of ISCO treatment will result in further risk reduction at the site. All required ISCO equipment will be mobilized to the site. As part of mobilization, a site specific Health and Safety Plan and Quality Assurance Plan will be prepared. All other necessary tools and equipment will be acquired, expedited, and placed at the site and chemicals will be delivered and placed in the designated storage areas. The area will be cleared for treatment. All debris generated from clearing activities will be located onsite for re-use or disposed in accordance with applicable standards. Saturated Soil The saturated soil treatment application will consist of approximately 8,640-pounds of hydrogen peroxide diluted to 20% concentration with clean tap water for injection of 4,800-gallons. Approximately 300- gallons of iron catalyst (ferrous sulfate) will be injected into the injection points to facilitate the chemical reaction. Approximately sixty-four (64) injection points gridded on 5-feet centers will be used for the treatment application. The application depths will be between 17 and 21-feet bgs. Three injection events will be conducted with verification samples collected following each event. The Soil Injection Area Map is included as Figure 2A-i. All equipment will be cleaned and stored at the end of each day. The area of treatment will be cleaned for the following day's operations and all wastes shall be stored for final disposition. Soil verification samples will be collected at the conclusion of each treatment application and analyzed for VOCs by EPA method Sample results may be used to modify or delineate the treatment areas in the succeeding treatment applications. Groundwater The groundwater treatment application will consist of approximately 40,000-pounds of sodium persulfate to be diluted to a 15% concentration with clean tap water for injection of 29,000-gallons. Approximately 6,000-gallons of 25% concentration sodium hydroxide (caustic soda solution) will be added to the TCEQ-10326/RAP February

22 Response Action Design Associated Information: Attachment 2A, 2B, 2C RAP Worksheet 2.0 ID No.: VCP ID No Page of Report Date: March 2012 mixture prior to injection to activate the solution. The average daily injection is estimated to be 3,000- gallons. Twenty-five (25) 1-inch diameter injection wells will be installed for the treatment application. The Groundwater Injection Area Map is included as Figure 2A-ii. All equipment will be cleaned and stored at the end of each day. The area of treatment will be cleaned for the following day's operations and all wastes shall be stored for final disposition. Groundwater verification samples will be collected at the conclusion of the treatment application and analyzed for VOCs by EPA method Sample results will be used to document COC concentration changes in the treatment area. The effectiveness of the ISCO treatment approach will be evaluated through confirmation groundwater samples collected following treatment. A quarterly groundwater monitoring program may be conducted to further evaluate the effectiveness of the treatment. A MSD will be obtained for the site restricting the use of groundwater to prevent exposure to human receptors. It is anticipated that the MSD will be fully protective of human health and the environment and meet response objectives in a reasonable time frame for the affected property without physical or institutional controls. The ISCO treatment will further reduce COC concentrations at the site and facilitate future development of the area. No ecological services analysis and compensatory restoration plan is anticipated. Describe all major treatment system components and equipment of the response action. Illustrate the response action design and provide equipment specifications in Attachment 2A. The equipment used in the ISCO treatment of the Saturated Soil COC Zone will consist of a geogrid, tripod frames, a high pressure lance and injection unit including pumps, a transfer pump, tankage, an air compressor, and all injection items. The equipment used in the ISCO treatment of the Groundwater COC Zone will consist of twenty-five 1- inch diameter injection wells installed to approximately 25-feet bgs, a high/low pressure injection unit including pumps, a transfer pump, tankage, a mixer, and all injection items. List permits or registrations needed to construct or implement the response action, including permits or registrations needed to conduct studies or tests. For VCP sites, list the permits that would be required if the site was not in the VCP (required by the VCP). Permitting/Registration Authority Type of permit/registration Permit or registration number if already issued TCEQ Class V Injection Well Permit Authorization No. 5X NA Anticipated application date Identify and discuss the results of any studies or tests, such as pilot studies, feasibility studies, technical impracticability studies, treatability studies, and/or toxicity studies conducted or proposed to be conducted at the affected property. Discuss the reason for the study or test and how it verifies the effectiveness and appropriateness of the chosen response action or documents that a particular response action is not appropriate for the affected property. Describe how the results of completed studies or tests determined the design or choice of response action. Attach any separate reports and supporting documentation in Appendix 3. A bench scale study was conducted to determine the ratio and concentration of hydrogen peroxide and sodium persulfate oxidants to be injected. The study included several tests of Fenton s Reagent with 10 percent to 30 percent concentration of hydrogen peroxide. Soil was tested for soil oxidant demand. The TCEQ-10326/RAP February

23 Response Action Design Associated Information: Attachment 2A, 2B, 2C RAP Worksheet 2.0 ID No.: VCP ID No Page of Report Date: March 2012 study was designed to predict the injection volumes and concentrations most appropriate to achieve the response action objectives. A copy of the bench scale study is included in Appendix 3. TCEQ-10326/RAP February

24 ATTACHMENT 2A RESPONSE ACTION DIAGRAMS AND COMPONENT/EQUIPMENT DESCRIPTIONS

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27 Information on the existing monitoring wells and well construction diagrams is presented in the Affected Property Assessment Report.

28 ATTACHMENT 2B PROPOSED WELL DESIGN

29 1 inch - Injection Well Diagram 6-inch Manway (Surface Completion) if required 1-inch Injection Well with PVC Male adapter (threaded) and Cap (threaded) Non-shrink Cement/Grout Well Depth = 25 feet Bentonite Pack Sand Pack (2 foot above screened interval) Screened Injection Area Approx. 10 feet in GW Zone Screen = 10 feet

30 No additional monitor wells are proposed for the subject site.

31 ATTACHMENT 2C ESA AND COMPENSATORY RESTORATION PLAN

32 No ESA or compensatory Restoration Plan will be utilized.

33 Performance Measures and Potential Problems Performance Measures RAP Worksheet 3.0 ID No.: VCP ID No Page of Report Date: March 2012 List and describe the performance measures for each environmental medium containing a PCLE zone that will be used to determine if reasonable progress is being made by the response action in a timely manner. Use these measures to document effectiveness of the response action in the RAER. COCs in the soil and groundwater are below the Critical Residential PCLs with a MSD established for the site. The response objective for the ISCO treatment is to reduce COC mass in the saturated soils between 17 and 21-feet bgs and to reduce vinyl chloride concentrations in groundwater from below the Tier 2 PCL to below the Tier 1 PCL with a MSD. Three injection events will be conducted for the saturated soils using sixty-four temporary injection points. Following the completion of each soil ISCO treatment, verification soil samples will be collected to document changes in COC concentrations. Three verification soil samples from 19 to 20-feet bgs will be collected from each 500-square feet (approximate) within the COC zone following each soil treatment. The analytical results of the initial event may be used to modify subsequent events. If the results of confirmation sampling indicate that COC concentrations exceed the Tier 1 Residential Air GW-Soil Inh-V PCLs, subsequent treatment applications will be conducted and additional confirmation samples collected to insure the response objectives are achieved. The ISCO treatment of the groundwater will be conducted using twenty-five injection wells. At the conclusion of the groundwater injection event, groundwater samples will be collected from four monitor wells within the affected groundwater area to document the changes in COC concentrations. Four quarterly monitoring events may be conducted at the subject property to further document the effectiveness of the treatment. Potential Problems Complete the table for the response action. When the response action consists of several components or multiple actions, complete one table for each major component or action. Response Action Name/Designation: Groundwater Treatment List the potential problems that might be reasonably anticipated for the response action, describe the impact of each problem, and the response to the problem. Description of the Potential Problem Impact Will this cause a response action failure? Corrective Response Reduction in COC concentrations is not documented. None. The concentrations are below the Tier 2 Critical PCL. Yes No X TCEQ-10326/RAP February

34 Monitoring and Sampling Associated Information: Attachment 3A RAP Worksheet 3.1 Page of ID No.: VCP ID No Report Date: March 2012 List the monitoring and sampling of COC concentrations or other parameters that will be conducted during the response action. Illustrate the monitoring or sampling locations in Attachment 3A. If statistics or geostatistics will be used, provide details in Appendix 7. If monitoring or observation wells will be constructed for the response action, provide well construction details in Attachment 2B if not previously provided. Monitored Media COC 1 Other parameter (specify) Surface Soil NA Sampling Method 2 Sampling points or locations 3 Depth/Height 4 (ft.) Analytical or Field Screening Method Sampling or Monitoring Frequency 5 Subsurface Soil NA Groundwater VOCs Low-Flow MW-2, MW-7d, MW-9d, MW-10d EPA 8260 Upon completion of ISCO treatment. Surface water NA Sediment NA Air NA Other Media (Saturated Soil) VOCs Goeprobe 3 sample points per ISCO injection 19-20' EPA 8260 Upon completion of ISCO injection. Explain the reasons for the above-listed monitoring and sampling plan. The saturated soil and groundwater monitoring and sampling plan is designed to collect data that will be used to evaluate the effectiveness of the ISCO treatment response action for the COCs at the site. The analytical data will provide a method to evaluate the COC concentrations. Groundwater monitoring may be conducted for four quarterly events to further evaluate the effectiveness of the ISCO treatment. 1 Specify the COCs to be monitored in this media. List either type of COC (such as VOCs, metals) if all the COCs of that type will be monitored the same way. 2 Describe the sampling or monitoring methods and QC procedures in Appendix 1 unless the proposed sampling or monitoring procedure is the same as the sampling or monitoring procedure described in the APAR. 3 Specify the sampling or monitoring point, such as the specific monitor well or general sampling or monitoring location. 4 Specify the depth or height of the sampling or monitoring points. 5 Specify the frequency at which this monitoring or sampling will occur. TCEQ-10326/RAP February

35 ATTACHMENT 3A MAP OF MONITORING AND SAMPLING POINTS

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38 The saturated soil sampling points to evaluate the effectiveness of the ISCO treatment area will be installed in the area of soil boring SB-8. The locations of additional soil sampling points will be determined from confirmation sampling results and subsequent treatment events.

39 Operation and Maintenance RAP Worksheet 3.2 ID No.: VCP ID No 2076 Page of Report Date: March 2012 Use this worksheet to describe the operation and maintenance (O&M) activities for each response action. In situations where the response action consists of more than one major component, for clarity one worksheet can be completed for each major component. Response Action Name/Designation: Almeda Central Development Property List all portions of the response action to which this information applies. Describe the O&M and inspection activities that will be required to operate and maintain response action components. NA The response action will result in the destruction of COC mass upon treatment. No O&M and inspection activities will be required. List and discuss the key operating parameters for a properly functioning response action. Address how changes in these parameters will result in operating changes, providing sufficient detail to explain how the operator will know the component is functioning properly. NA See Above. List the routine tasks required to operate the response action. NA List the routine tasks required to maintain the response action, including scheduled inspections, maintenance, and component replacement. NA TCEQ-10326/RAP February

40 Confirmation Sampling Plan Associated Information: Attachment 4A RAP Worksheet 4.0 Page of ID No.: VCP ID No Report Date: March 2012 List the COCs and other parameters that will be sampled to confirm completion of the response action. Illustrate the monitoring or sampling locations in Attachment 4A. If monitoring or observation wells will be constructed for the response action, provide well construction details in Attachment 2B if not previously provided. If needed, describe the sample collection and handling methods, if not previously provided, in Appendix 6. Media COC 1 Other parameter (specify) Surface Soil NA Sampling Method Sampling points 2 Depth/height (ft.) Analytical Method Sampling Frequency Subsurface Soil NA Groundwater VOCs Low-Flow MW-2, MW- 7d, MW-9d, MW-10d EPA Event, following injection Surface water NA Sediment NA Air NA Other media (Saturated Soil) VOCs Geoprobe 3 sample points adjacent to SB ' EPA Events, 1 per injection event Explain the reasons for the above-listed sampling plan. Discuss statistical or geostatistical methodology(ies) which will be applied, if any, in the data collection process. Discuss any assumptions made in the statistical/geostatistical assessment, and how they will be met. The soil sampling plan is designed to document changes in COC concentrations in the saturated soils. Three verification soil samples from 19 to 20-1 Specify either a specific COC or type of COC (such as VOCs, metals). 2 Specify the sampling point to the degree it is known, (for example, MW-1, or near former boring #2). TCEQ-10326/RAP February

41 Confirmation Sampling Plan Associated Information: Attachment 4A RAP Worksheet 4.0 Page of ID No.: VCP ID No Report Date: March 2012 feet bgs will be collected from each 500-square feet (approximate) within the COC zone following each soil treatment. The analytical results of the initial event may be used to modify subsequent events. If the results of confirmation sampling indicate that COC concentrations exceed the Tier 1 Residential Air GW-Soil Inh-V PCLs, subsequent treatment applications will be conducted and additional confirmation samples collected to insure the response objectives are achieved. The groundwater confirmation sampling plan is designed to collect data that will be used to evaluate the effectiveness of the ISCO treatment response action for the COCs in groundwater at the site. The analytical data will provide the COC concentrations following treatment. TCEQ-10326/RAP February

42 ATTACHMENT 4A MAP OF CONFIRMATION SAMPLING POINTS

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45 Implementation Schedule RAP Worksheet 6.0 Page of ID No.: VCP ID No Report Date: March 2012 Document the proposed schedule for implementing the response action. Include all major response action activities through the life of the project, including all removal, decontamination, and control actions, component installations, O&M, monitoring, and post-response action care activities. Implementation of Response Action (specify component or action) Start Finish Duration Bench Scale Study Completed Completed Saturated Soil delineation April 2012 April month Remedial Implementation ISCO Treatment April 2012 May months Verification Sampling April 2012 May months List the proposed schedule for report submittals. Add additional lines if more reports than listed will be needed to complete the response action. Reports Submittal date Response Action Effectiveness Report (RAER) RAER submittal number 1 RAER submittal number 2 RAER submittal number 3 Response Action Completion Report (RACR) August 2012 Post-Response Action Care Report (PRACR) PRACR submittal number 1 PRACR submittal number 2 PRACR submittal number 3 TCEQ-10326/RAP February

46 APPENDIX 1 REFERENCE LIST

47 Reference List Bureau of Economic Geology, 1982, Houston Sheet, Geologic Atlas of Texas. Environmental Protection Agency, April 1996, Low-flow (Minimal Drawdown) Ground-Water Sampling Procedures, EPA/540/S-95/504. TCEQ Voluntary Cleanup Program, January 5, 1998, Groundwater Sampling Filtering, Low Flow Purging. Texas Department of Water Resources, September 1979, Groundwater Availability in Texas, Report 238. Texas Commission on Environmental Quality, February 2009, Soil and Groundwater Response Objectives, Regulatory Guidance TRRP-29. USDA Soil Conservation Service, 1976, Soil Survey of Harris, County, Texas. USGS, Bellaire, Texas, 7.5 minute quadrangle, Texas Water Development Board, February 2006, Aquifers of the Gulf Coast of Texas, Report 365.

48 APPENDIX 2 DATA TABLES AND BORING LOGS

49 Groundwater data tables and monitor well boring logs are presented in the Affected Property Assessment Report and the Affected Property Assessment Report Addendum.

50 APPENDIX 3 STUDIES/TESTS DOCUMENTATION

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128 APPENDIX 6 SAMPLING PROCEDURES

129 All sampling procedures will be conducted in accordance with the procedures documented in the APAR