Former MCAS Tustin - Fourth CERCLA 5-Year Review Completed

22 January 2022

From Ms. Kyle Olewnik

The United States Department of the Navy (Navy), in coordination with state environmental regulatory agencies, has completed the Fourth Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Five-Year Review (FYR) for Operable Units (OUs) 1A, 1B, 3, and 4B at Former Marine Corps Air Station (MCAS) Tustin, Tustin, California. The Navy conducted the FYR in accordance with the requirements of CERCLA Section 121(c) to determine whether the remedies being implemented in accordance with the Final Records of Decision (RODs) continue to remain protective of human health and the environment.

OUs 1A and 1B (Installation Restoration Program [IRP] Sites 3, 12, and 13S)

Remedy. The remedy includes extracting, treating, and preventing the migration of groundwater (GW) impacted by volatile organic compounds (VOCs); excavating and disposing of VOC-impacted soil off site; monitoring GW quality; and implementing institutional controls (ICs).
Protectiveness statement. The remedy remains protective of human health and the environment in the short term; additional actions are needed to achieve long-term protectiveness. Certain per- and polyfluoroalkyl substances (PFAS) are present in groundwater at concentrations exceeding non-promulgated United States Department of Defense (DoD) residential screening levels. The Navy has brought PFAS into its CERCLA program and is finalizing a Preliminary Assessment/Site Inspection (PA/SI) Report as the first step to address these emerging contaminants. For 1,2,3- trichloropropane (1,2,3-TCP) in OU-1A GW, the remedy is currently protective with respect to the remediation goal (RG) established in the Final ROD. However, additional action is required to establish long-term protectiveness given that the California Maximum Contaminant Level (MCL) is 100 times less than the RG. The Navy is currently conducting additional groundwater monitoring and modeling to assess the extent of the 1,2,3-TCP plumes in the first, second, and third water-bearing zones at OU-1A relative to the California MCL. In addition, the Navy is completing legal and technical analysis regarding the adoption of the California MCL for 1,2,3-TCP as the RG. Also, for long-term protectiveness, the remedy requires finalization of the Revised Draft Final Land Use Control Remedial Design Amendment No. 1 to establish and implement additional vapor intrusion–specific ICs in accordance with the Revised Draft Final Explanations of Significant Differences to the Final RODs, which are also being finalized.

OU-3 (IRP Site 1)

Remedy. The remedy includes constructing engineering controls to prevent contact with and migration of subsurface contamination; monitoring GW and surface water; and implementing ICs. • Protectiveness statement. The remedy remains protective of human health and the environment in the short term; additional actions are needed to achieve long-term protectiveness. PFAS are present in groundwater at concentrations exceeding non-promulgated DoD residential screening levels, and the Navy is finalizing a PA/SI Report as the first step in the CERCLA process to address these emerging contaminants.

OU-4B Low Concentration Sites (IRP Sites 11 and 13W)

Remedy. The remedy includes monitoring VOC-impacted GW and implementing ICs.
Protectiveness statement: The remedy remains protective of human health and the environment in the short term; additional actions are needed to achieve long-term protectiveness. PFAS are present in groundwater at concentrations exceeding non-promulgated DoD residential screening levels, and the Navy is finalizing a PA/SI Report as the first step in the CERCLA process to address these emerging contaminants.

OU-4B Moderate Concentration Sites (IRP Sites 5S, 6, and the Mingled Plumes Area)

Remedy. The remedy includes conducting in situ bioremediation and monitored natural attenuation of VOC-impacted GW and implementing ICs.
Protectiveness statement. The remedy remains protective of human health and the environment in the short term; additional actions are needed to achieve long-term protectiveness. PFAS are present in groundwater at concentrations exceeding non-promulgated DoD residential screening levels, and the Navy is finalizing a PA/SI Report as the first step in the CERCLA process to address these emerging contaminants.

Questions or comments regarding the Fourth CERCLA FYR or other Navy environmental activities at Former MCAS Tustin may be directed to:

Ms. Kyle Olewnik
Base Realignment and Closure Environmental Coordinator
Base Realignment and Closure Program Management Office West
33000 Nixie Way, Building 50, Suite 207
San Diego, CA 92147
(619) 524-4048
kyle.e.olewnik.civ@us.navy.mil

FOR MORE INFORMATION
Information regarding Former MCAS Tustin and the remediation efforts at these OUs is available at the following website and locations: F ormer MCAS Tustin webpage

Related Documents:
Fourth CERCLA 5-Year Review

Contact

Ms. Kyle Olewnik
Navy BRAC Environmental Coordinator
33000 Nixie Way, Blg. 50
San Diego, CA 92147
Phone: (619) 524-5901
Email: kyle.olewnik@navy.mil

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