Five Year Review Summary Form 4 I
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US EPA RECORDS CENTER REGION 5 11111111111111111111111111\ 1\11\ 1\\\ 1111 462646 \ FOURTH FIVE-YEAR REVIEW REPORT FOR TWIN CITIES AIR FOI{CE RESERVE BASE, S~LARMSRANGELANDnLL HENNEPIN COUNTY, MINNESOTA Prepared by 934th Airlift Wing, U.S. Air Force Reserve Minneapolis-St. Paul International Airport Air Reserve Station Minneapolis, Minnesota Approved by: . lJIlAi /3 R Date I ~ J ar . rl, i eet r ./ CSupe nd Division U.S. Environmental Protection.Agency, Region 5 TABLE OF CONTENTS List of Acronyms 3 Executive Summary 4 Five Year Review Summary Form 4 I. Introduction 6 II. Site Chronology 8 III. Background 8 Physical Characteristics 8 Land and Resource Use 9 History ofContaluination 9 Initial Response 10 Basis for Taking Action 10 IV. Remedial Actions 11 Remedy Selection 11 Remedy Implementation 11 Institutional Controls 13 System Operations/Operation and Maintenance (O&M) 15 V. Progress Since the Last Review .15 Status of Recommendations and Follow-up Actions from Last Review 15 Status ofOther Prior Issues 15 VI. Five-Year Review Process 16 Administrative COluponents 16 Community Notification and Involvement 16 Document Review 16 Data Review 17 Site Inspection 18 VII. Technical Assessment 18 Question A: Is the remedy functioning as intended by the decision documents? 18 Question B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives used at the time of the remedy selection still valid? 20 Question C: Has any other information come to light that could call into question the protectiveness of the remedy? 22 YIn. Issues 22 IX. Recommendations and Follow-up Actions 22 X. Protectiveness Statement 23 XI. Next Review 23 Appendices Appendix A - Figures Figure 1 - Location Map Figure 2 - Site Map Appendix B - Tables Table 1 - Groundwater Contaminants ofConcern and Applicable or Relevant and Appropriate Requirements Table 2 - Surface Water Contaminants ofConcern and Applicable or Relevant and Appropriate Requirements Table 3 - Soil Contaminants of Concern Table 4 - Institutional Controls Summary Table 5 - History of Monitoring Results for Inorganic Contaminants of Concern Monitoring Wells MW06, MW8A, MW9A Appendix C - Public and State Regulatory Agency Notifications Notification Letter to Minnesota Pollution Control Agency Public Notice 2 LIST OF ACRONYMS ARARs Applicable or Relevant and Appropriate Requirements ARS Air Reserve Station CERCLA Comprehensive Environmental Response, Compensation and Liability Act CL Compliance Level COC Contaminant ofConcern EOD Explosive Ordnance Disposal FFA Federal Facility Agreement FS Feasibility Study HRL Health Risk Limit IC Institutional Control ICIAP Institutional Controls Implementation and Assurance Plan MAC Metropolitan Airports Commission MCL Maximum Contaminant Level MSP lAP Minneapolis-St. Paul International Airport MSPIAP ARS Minneapolis-St. Paul International Airport Air Reserve Station MPCA Minnesota Pollution Control Agency MW Monitoring Well NCP National Contingency Plan NGVD National Geodetic Vertical Datum -NPL National Priorities List O&M Operation and Maintenance RAL Recommended Allowable Limit ROD Record of Decision R1 Remedial Investigation SARL Small Arms Range Landfill SVOC Semi-volatile Organic Compound SWRAU Site-Wide Ready for Anticipated Use TL Trigger Level USAF United States Air Force USAFR United States Air Force Reserve USEPA United States Environmental Protection Agency UUIUE Vnlimited Use or Unrestricted Exposure VOC Volatile Organic Compound 934AW 934th Airlift Wing 3 EXECUTIVE SUMMARY This report documents the fourth Five-Year Review for the "Twin Cities 'Air Force Reserve Base, Small Arms Range Landfill," a former National Priorities List site located on the Snelling Small Arms Range Annex property at the Minneapolis-St. Paul International Airport Air Force Reserve Station. In May 2012, Pace Analytical Services, Inc. completed confirmatory sampling and analysis of groundwater at the Small Arms Range Landfill. , Representatives of U.S. Environmental Protection Agency Region 5 Superfund Division and the U.S. Air Force Reserve's 934th Airlift Wing performed a site inspection in May 2012 to evaluate the site access restrictions and site maintenance. Based on the analytical results and the observed conditions during the site inspection, the remedial actions implemented at the Small Anns Range Landfill remain protective of human health and the environment. FIVE-YEAR REVIEW SUMMARY FORM SITE IDENTIFICATION . Site Name: Twin Cities Air Force Reserve Base Small Arms Firing Range Landfill (SARL) EPA 10: MN8570024275 NPL Status: Deleted Multiple OUs? Has the site achieved construction completion? No Yes : REVIEW STATUS Lead agency: Other Federal Agency If "Other Federal Agency" was selected above, enter Agency name: U.S. Air Force Author name (Federal or State Project Manager): Douglas Yocum Author affiliation: 934th Airlift Wing, U.S. Air Force Reserve Review period: 07/29/2008 - 07/28/2013 Date of site inspection: OS/22/2012 Type of review: Statutory Review number: 4 Triggering action date: 07/28/2008 Due date (five years after triggering action date): 07/28/2013 4 FIVE-YEAR REVIEW SUMMARY FORM (CONTINUED) I Issues/Recommendations ' I QU(s) without Issues/Recommendations Identified in the Five-Year Review: SARL Issues and Recommendations Identified in the Five-Year Review: Not applicable I Sitewide Protectiveness Statement I Protectiveness Determination: Protective Protectiveness Statement: Institutional Controls (ICs) for the site property and groundwater, which are required to ensure no inappropriate use of the site or use of groundwater, are in-place and effective. The remedy is functioning as intended because no inappropriate site uses are occurring, and no groundwater use is occurring. Long term protectiveness requires compliance with effective ICs. Compliance with effective ICs will be ensured through long-term stewardship by maintaining and monitoring effective ICs as well as maintaining the site remedy components. Because the remedial actions at the SARL are protective, the site is protective of human health and the environment. 5 Fourth Five-Year Review Report I. Introduction The Small Anns Range Landfill (SARL) site is a two-acre site located on an Air Force-owned parcel of property known as the Snelling Small Anns Range Annex, within the "Fort Snelling Unorganized Territory" of Hennepin County, Minnesota. The property is south-southeast of the Minneapolis-St. Paul International Airport (MSP lAP), and is bordered by Fort Snelling State Park to the north; the Minnesota River to the east; Interstate 494 and the Minnesota Valley National Wildlife Refuge to the south; and Minnesota Highway 5 to the west. A location map is presented in Appendix A, Figure I. The Snelling Small Arms Range Annex property is a geographically-separated unit of the Minneapolis-St. Paul International Airport Air Reserve Station (MSP lAP ARS), fonnerly known as the "Twin Cities Air Force Reserve Base." The 934th Airlift Wing (934 AW), U.S. Air Force Reserve, has control and oversight of the Snelling Small Anns Range Annex property, including the SARL. The SARL is within the 100 year flood plain for the Minnesota River and is prone to flooding, according to data produced in 2004 by the U.S. Anny Corps of Engineers and the U.S. Geological Survey. There is no residential property located within a one mile radius of the SARL. The SARL site was used as an unpermitted landfill/dump site for approximately nine years. The site Record of Decision (ROD) identified contaminants of concern (COCs) for groundwater, surface water, and soils at the site. Groundwater COCs included twelve metals, five volatile organic compounds (YOCs), and one semivolatile organic compound (SYOC). Surface water COCs included six metals and one YOC. Soil COCs included five metals and one YOc. The ROD signed by the U.S. Air Force (USAF) and U.S. Environmental Protection Agency (USEPA) established Contaminant-Specific Applicable or Relevant and Appropriate Requirements (ARARs) for the site as federal drinking water Maximum Contaminant Levels (MCLs) and State of Minnesota Recommended Allowable Limits (RALs) for groundwater COCs, and Federal Ambient Water Quality Criteria for surface water COCs. COCs for groundwater, surface water and soil, as well as Contaminant-Specific ARARs, are identified in Appendix B, Tables 1, 2 and 3. There were no Contaminant-Specific ARARs established for soil COCs. Location-specific ARARs and Action-Specific ARARs were not identified in the ROD. The selected remedy for the SARL consisted of natural attenuation of groundwater contamination, access restrictions, site maintenance and monitoring, and institutional controls. The Purpose of the Review The purpose of the Statutory Five-Year Review is to detennine whether the remedy selected and implemented for the SARL continues to be protective of human health and the environment. This Five-Year Review report identifies issues found during the review, if any, and provides recommendations to address them. Previous Five-Year Reviews were documented in 1998, 2003, and 2008. 6 Authority for Conducting the Five-Year Review This statutory Five-Year Review is conducted pursuant to Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 121(c) (42 USC § 9621(c)) and the National Contingency Plan (NCP). CERCLA Section 121 states: Ifthe President selects a remedial action that results in any hazardous substances, pollutants, or contaminants remaining at the site, the President shall review