Travis Air Force Base, California Groundwater Five-Year Review
Total Page:16
File Type:pdf, Size:1020Kb
Travis Air Force Base, California Groundwater Five-Year Review Executive Summary Travis Air Force Base (Travis AFB or Base), levels of contamination and potential risk, with public and regulatory acceptance, is and collect some of the data necessary for implementing interim groundwater the selection of final cleanup levels and tech- remedies at multiple contaminated sites. nically and economically feasible long-term This Groundwater Five-Year Review Report actions. The use of IRODs allowed actions to evaluates whether the interim remedies are proceed without having final designated protective of human health and the environ- cleanup levels, as will be required for the ment and are functioning as designed. Final Basewide Groundwater Record of Specifically, the five-year review provides Decision (ROD). The interim actions taken the following information: under the IRODs use interim remediation goals as performance objectives. These are · States whether the interim remedy is, or not legally enforceable standards, but are is expected to be, protective simply goals during the period of interim · Lists deficiencies identified during the long-term operation (LTO). review Travis AFB is the lead agency and responsible · Recommends specific actions to ensure party for the groundwater remediation actions that a remedy will be, or will continue to being evaluated in this first five-year review. The be, effective San Francisco Bay Regional Water Quality Control Board (SFBRWQCB), EPA, and This first Groundwater Five-Year Review Department of Toxic Substances Control Report is required by statute and is prepared (DTSC) provide regulatory agency oversight. in accordance with the U.S. Environmental Protection Agency (EPA) Comprehensive Funding of groundwater remediation efforts Five-Year Review Guidance (EPA, 2001). is provided by the Department of Defense to The interim groundwater remedies are being the Air Mobility Command. The Air implemented in accordance with the Mobility Command then allocates these Groundwater Interim Record of Decision funds to Travis AFB according to priorities (IROD) for the North/ East/ West Industrial determined by the Air Force. Subsequently, Operable Unit (NEWIOU) (Travis AFB, 1997) the Air Force Center for Environmental and the Groundwater IROD for the Excellence (AFCEE) provides administration West/Annexes/ Basewide Operable Unit of these funds. The allocation of available (WABOU) (Travis AFB, 1999). funds is continually under review by the Air Force and is subject to alteration. Such The interim remedies were designed and funding changes are typically outside the constructed to quickly begin remediation of control of Travis AFB. Accordingly, the groundwater contamination, reduce the RDD/030910018 (CAH2328.DOC) VII GROUNDWATER FIVE-YEAR REVIEW EXECUTIVE SUMMARY precise schedule of groundwater The primary groundwater contaminants remediation efforts is uncertain. Table ES-1 exceeding the interim remediation goals shows that optimization established by the NEWIOU and WABOU opportunities/further actions are identified IRODs include chlorinated volatile organic for some sites (located at the end of this compounds, primarily trichloroethylene and executive summary). A detailed schedule related compounds. Petroleum-fuel cannot be developed at this time, but Travis constituents, organochlorine pesticides, and AFB will consult with the SFBRWQCB, EPA, other contaminants are also present in some and DTSC to develop a schedule that is places. acceptable to all parties. Interim Remedial Action Objectives Background Groundwater interim remedial actions (IRA) have, as specified in the two IRODs, been Physical Setting designed and constructed to achieve the following basic interim remedial objectives: Travis AFB occupies approximately 6,000 acres and is located midway between · Source Control – hydraulically contain San Francisco and Sacramento, California. and remove contaminant mass from the Facilities include two major runways, groundwater and vadose zone using associated taxiways and aircraft parking groundwater extraction and treatment aprons, numerous hangars, buildings, shops, (GET) and vapor extraction and offices, freight handling and storage areas, treatment and maintenance facilities. Approximately · Migration Control – hydraulically 17,000 military and civilian personnel are contain contamination using a GET present daily on the Base. system and/or program of monitored Travis AFB is part of Air Mobility Command natural attenuation (MNA) and is host to the 60th Air Mobility Wing and · Offbase Remediation – hydraulically other units. The Air Mobility Wing operates contain and remediate plumes down to C-5 Galaxy cargo aircraft and KC-10 the contaminant-specific interim Extender refueling aircraft. The primary remediation goal using a GET system missions of Travis AFB, since its establish- ment in 1943, have been strategic recon- A summary of the IRA objectives for each naissance and airlift of freight and troops. IRP site is provided in Table ES-1. Groundwater Contamination Monitored Natural Attenuation As a result of past waste management and The Natural Attenuation Assessment Plan disposal practices, groundwater at Travis (NAAP) is the governing document for sites, AFB is contaminated at multiple locations. or portions or sites, undergoing assessments of MNA (CH2M HILL, 1998). The protocols The locations of groundwater contamination provided in the NAAP are the basis for and Installation Restoration Program (IRP) determining if the Migration Control sites are shown on Figure ES-1 and Plate 1. objective has been achieved and the VIII RDD/030910018 (CAH2328.DOC) GROUNDWATER FIVE-YEAR REVIEW EXECUTIVE SUMMARY contaminant plume has been stabilized through natural physical, chemical, and biological processes. In accordance with the IRODs and NAAP, multiple sites at Travis AFB are undergoing MNA assessment during the period of interim remedial action. These sites include: · LF006 – formally selected for MNA in the NEWIOU Groundwater IROD · FT004 – MNA assessment combined with GET · SD031 – MNA assessment combined with GET RDD/030910018 (CAH2328.DOC) IX GROUNDWATER FIVE-YEAR REVIEW EXECUTIVE SUMMARY Figure ES-1 Consolidated Groundwater Interim Remedial Actions 11 x 17 color X RDD/030910018 (CAH2328.DOC) GROUNDWATER FIVE-YEAR REVIEW EXECUTIVE SUMMARY Figure ES-1 continued RDD/030910018 (CAH2328.DOC) XI GROUNDWATER FIVE-YEAR REVIEW EXECUTIVE SUMMARY · LF007B – MNA assessment MNA assessments are underway in portions of plumes that are also undergoing GET. · LF007C – MNA assessment combined These plumes include FT004, SD031, with GET LF007C, SD033, SD037, and DP039. In · LF007D – MNA assessment these plumes, the higher concentration areas are undergoing GET for the purposes of · SS014 – petroleum fuels commingled Source Control and/or Migration Control with chlorinated hydrocarbons and the lower concentration areas (i.e., · SD033 – MNA assessment combined hydraulically downgradient of the GET with GET system) are under assessment to determine if MNA can provide effective Migration · SD037 – MNA assessment combined Control. However, until the GET component with GET of the interim remedy is completed and the · SS015 – MNA assessment deferred extraction wells turned off, the MNA pending enhanced biodegradation component cannot be fully evaluated treatability study because migration of the upgradient plume into the MNA assessment plume area may · DP039 – combined with GET, reactive result in increased contaminant wall treatability study, and concentrations. phytoremediation treatability study MNA appears successful at stabilizing the The listed sites initially underwent LF006, LF007B, and LF007D plumes. MNA, preliminary assessment of biodegradation in conjunction with GET, appears successful factors as part of the preparation of Natural at stabilizing the FT004 and SD031 plumes. Attenuation Assessment Work Plans. The At other MNA sizes, more data are needed plans established that, on an ongoing basis, before conclusions may be drawn. At one the MNA assessments would consist site, LF007C, MNA has not been successful. primarily of an assessment of plume Because contamination is migrating offbase stability. The Five Year Review, therefore, at this site, MNA has been replaced with focuses on plume stability as the main, but GET. not sole, criterion in assessing the success of MNA. Site Consolidation In the list above, LF006 and DP039 are the Travis AFB has constructed multiple only sites at which MNA was selected as the groundwater IRAs to achieve the Source interim remedy. For the remainder of the Control, Migration Control, and Offbase sites, a Natural Attenuation Summary Remediation interim objectives. Both IRODs Report will be prepared in the future, that prescribe site-specific groundwater IRAs for will make recommendations whether MNA the applicable IRP sites. Historically, these should be selected as a final remedy at the IRAs have been described in terms of the sites. The Natural Attenuation Summary actions taken at the individual sites and, in Report will be prepared in accordance with some cases, at collections of sites. However, the NAAP. since issuance of the LTO Strategic Plan, a more appropriate strategy has been XII RDD/030910018 (CAH2328.DOC) GROUNDWATER FIVE-YEAR REVIEW EXECUTIVE SUMMARY employed by consolidating site-specific IRAs for future Risk-based Corrective IRAs with common key components into Actions (RBCA) in accordance with the regional IRAs (CH2M HILL, 2001). The POCO Sites Work Plan (IT Corporation,