EPA/ROD/R2005090001493 2005 EPA Superfund Record of Decision: CONCORD NAVAL WEAPONS STATION EPA ID: CA7170024528 OU 07 CONCORD, CA 09/30/2005 Final Record of Decision Inland Area Site 17 Naval Weapons Station Seal Beach Detachment Concord Concord, California GSA.0113.0012 Order N62474-03-F-4032; GSA-10F-0076K June 10, 2005 (Pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act) Department of the Navy Integrated Product Team West, Southwest Division Naval Facilities Engineering Command Daly City, California U.S. Environmental Protection Agency, Region 9 175 Hawthorne Street San Francisco, California Department of Toxic Substances Control 8800 Cal Center Drive Sacramento, California San Francisco Bay Regional Water Quality Control Board 1515 Clay Street, Suite 1400 Oakland, California Prepared by Tetra Tech EM Inc. 135 Main Street, Suite 1800 San Francisco, CA 94105 (415) 543-4880 DEPARTMENT OF THE NAVY BASE REALIGNMENT AND CLOSURE PROGRAM MANAGEMEN1 OFFICE WEST 1455 FRAZEE AD, SUITE 900 SAN DIEGO, CA 92’ 08-4310 5090 Ser BPMOW.JTD/0361 April 17, 2006 Mr. Phillip A. Ramsey US. Environmental Protection Agency Region IX 75 Hawthorne Street San Francisco. CA 94105 Dear Mr. Ramsey: The Final Record of Decision (ROD), Inland Area Site 17, Naval Weapons Station Seal Beach Detachment Concord, California, of June 10, ;!005, was fully executed on February 1, 2006. Copies of the ROD were provided to regulatory agencies shortly after final signatures. TMs letter is provided to you to document the transmittal of the ROD following its execution. Should you have any questions concerning this document or if you need additional information, please contact me at (619) 532-0975. By direction of the Director 5090 Ser BPMOW.JTD10361 April 17, 2006 copy to: - Mr. Jim Pinasco Mr. Alan Friedman (CD and hardcopy) California Department of Toxic Substances California Regional Water Quality Control Board Control San Francisco Bay Region Region 1 1515 Clay Street, Suite 1400 8800 Cal Center Drive Oakland, CA 94612 Sacramento, CA 95826 Mr. Frank Gray (CD and hardcopy) Ms. Joanna Canepa California Department of Fish and Game Tetr8eTech EM1 1700 K Street, Suite 250 6100 21gthStreet SW, Suite 550 Sacramento, CA 95814 -Mountlake Terrace, WA 98043 Ms. Margaret Wallerstein Ms. Mary Lou Williams Code N45WS Res1:oration Advisory Board NWS Seal Beach 1015 San Miguel Road 800 Seal Beach Boulevard, Building 110 Concord, CA 94518-21 10 Seal Beach, CA 90740-5000 Ms. Lisa Anich Mr. Kevin Cornish 4495 River Ash Ct 11 Ruth Court Concord, CA 94521 Lafayette, CA 94549 Mr. Gregory Glaser Mr. David Griffith 202 Sonora Avenue 4002: Hiller Lane Danville, CA 94526 Martinez, CA 94553 Ms. Jessica Hamburger (CD only) Mr. Mario Menesini 5552 Clayton Rd., 2406 Cascade Drive Concord CA 94521-4158 Walnut Creek, CA 94598 Mr. John Montagh Mr. Igor Skaredoff (CD only) 1950 Parkside Drive M/S 1B 41 1 Isabel Drive Concord, CA 94519 Martinez, CA 94553 Ms. Sonce de Vries Mr. laly Jolish Floor SFD-8-6 Floor ORC-3 75 Hawthorne Street 75 Hiwthorne Street San Francisco, CA 94105 San Francisco, CA. 94105 Ms. Laurie Sullivan Ms. Denise Klimas Floor SFD-8 Sacramento Regional Office (NOAA) 75 Hawthorne Street 8800 Cal Center Drive San Francisco, CA 94105 Sacramento, CA 95826 Ms. Carolyn Marn 2800 Cottage Way Room W2605 Sacramento, CA. 95825 2 CONTENTS ABBREVIATIONS AND ACRONYMS...................................................................................... iii 1.0 DECLARATION FOR NO ACTION AT NAVAL WEAPONS STATION SBD CONCORD, INLAND AREA SITE 17 ..............................................................................1 1.1 SITE NAME AND LOCATION.......................................................................................1 1.2 STATEMENT OF BASIS AND PURPOSE ........................................................................1 1.3 DESCRIPTION OF THE SELECTED REMEDY: NO ACTION............................................1 1.4 STATUTORY DETERMINATIONS.................................................................................2 2.0 DECISION SUMMARY FOR NAVAL WEAPONS STATION SBD CONCORD, INLAND AREA SITE 17....................................................................................................3 2.1 SITE NAME, LOCATION, AND DESCRIPTION...............................................................3 2.1.1 Physiography and Topography ....................................................................3 2.1.2 Local Geology and Groundwater Beneficial Use Determination................3 2.1.3 Local Hydrology ..........................................................................................7 2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES ........................................................8 2.2.1 Background..................................................................................................8 2.2.2 Environmental Investigations at Naval Weapons Station SBD Concord.............................................................................................12 2.2.3 IRP History for Site 17 ..............................................................................13 2.2.4 Estimation of Ambient Concentrations of Metals in Inland Area Soils........................................................................................15 2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION ........................................................16 2.4 SITE CHARACTERISTICS ..........................................................................................18 2.4.1 Results of Soil Investigations.....................................................................19 2.4.2 Results of Sediment Investigations............................................................24 2.4.3 Results of Groundwater Investigations......................................................24 2.5 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES..............................24 2.6 SUMMARY OF SITE RISKS........................................................................................27 2.6.1 Human Health Risk Assessment................................................................28 2.6.2 Ecological Risk Assessment ......................................................................34 2.6.3 Conclusions and Risk Management Evaluation ........................................35 2.7 DESCRIPTION OF NO ACTION ALTERNATIVE...........................................................37 2.8 DOCUMENTATION OF SIGNIFICANT CHANGES.........................................................38 REFERENCES ..............................................................................................................................39 Appendix A RESPONSIVENESS SUMMARY FOR INLAND AREA SITE 17 B HUMAN HEALTH RISK ASSESSMENT TABLES Final ROD Inland Area Site 17 i FIGURES 1 SITE LOCATION MAP......................................................................................................4 2 INLAND AREA RI SITES..................................................................................................5 3 SITE 17 – BUILDING IA-24 SITE FEATURES................................................................6 4 SITE 17 – SITE INVESTIGATION AND REMEDIAL INVESTIGATION SAMPLING LOCATIONS ...............................................................................................10 5 ORGANIC CONSTITUENTS DETECTED DURING THE RI AT SITE 17 IN SOIL .............................................................................................................................21 6 INORGANIC CONSTITUENTS DETECTED DURING THE RI AT SITE 17 IN SOIL .............................................................................................................................23 7 CHEMICALS DETECTED IN GROUNDWATER AT SITE 17 ....................................26 8 CONCEPTUAL SITE MODEL FOR HUMAN HEALTH RISK ASSESSMENT..........30 TABLES 1 INSTALLATION RESTORATION PROGRAM SITES .................................................14 2 AMBIENT CONCENTRATIONS OF METALS IN SOILS FOR INLAND AREA SITE 17 ..................................................................................................................17 3 ORGANIC CONSTITUENTS DETECTED IN SOILS AT SITE 17...............................20 4 INORGANIC CONSTITUENTS DETECTED IN SOILS AT SITE 17...........................22 5 ORGANIC AND INORGANIC CONSTITUENTS DETECTED IN SEDIMENT AT SITE 17...................................................................................................25 6 ORGANIC AND INORGANIC CONSTITUENTS DETECTED IN GROUNDWATER AT SITE 17 .......................................................................................27 7 RESULTS OF THE HUMAN HEALTH RISK ASSESSMENT FOR SITE 17 ..............33 Final ROD Inland Area Site 17 ii ABBREVIATIONS AND ACRONYMS µg/L Micrograms per liter ATSDR Agency for Toxic Substances and Disease Registry AWQC Ambient Water Quality Criteria BRAC Base realignment and closure BTEX Benzene, toluene, ethylbenzene, and xylene CCCHSD Contra Costa County Health Services Department CCWD Contra Cost Water District CERCLA Comprehensive Environmental Response, Compensation, and Liability Act COEC Chemical of ecological concern COPC Chemical of potential concern CSM Conceptual site model DTSC California Department of Toxic Substances Control EOD Explosive ordnance disposal EPC Exposure point concentration ERA Ecological risk assessment ER-M Effects range-median FFA Federal Facility Agreement FS Feasibility study HHRA Human health risk assessment HI Hazard index IAS Initial assessment study IRP