Navy Presentation on Site 27 to Moffett RAB July 17, 2008

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Navy presentation to the Moffett Field Restoration Advisory Board on July 17, 2008, regarding Site 27.

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Navy Presentation on Site 27 to Moffett RAB July 17, 2008

  1. 1. Sediment Removal Action Update INSTALLATION RESTORATION PROGRAM SITE 27 FORMER NAVAL AIR STATION MOFFETT FIELD RAB Meeting July 17, 2008
  2. 2. Outline <ul><li>Background / Site Layout </li></ul><ul><li>Contaminants and Target Cleanup Goals (TCGs) </li></ul><ul><li>Removal Action </li></ul><ul><li>Current Site Status </li></ul><ul><li>Remedial Action Completion Report (RACR) Update </li></ul>
  3. 3. Background <ul><li>The Navy conducted a removal action at Site 27 as part of the IRP at Moffett </li></ul><ul><li>For purposes of this removal action, Site 27 consists of: </li></ul><ul><ul><li>The Northern Channel, including the western portion of the channel berm (adjacent to Moffett), and the Lockheed Martin berm </li></ul></ul><ul><ul><li>Marriage Road Ditch </li></ul></ul><ul><ul><li>North Patrol Road Ditch </li></ul></ul><ul><ul><li>The debris pile in the vicinity of the Building 191 lift station </li></ul></ul>
  4. 4. Site Layout
  5. 5. Contaminants and Target Cleanup Goals <ul><li>The channels collect and move stormwater away from Moffett. The stormwater is eventually discharged to San Francisco Bay north of Moffett </li></ul><ul><li>This had resulted in deposition of sediments in the channels containing certain chemicals of ecological concern (COECs): </li></ul><ul><ul><li>Polychlorinated biphenyls (PCBs) </li></ul></ul><ul><ul><li>Pesticides </li></ul></ul><ul><ul><li>Metals </li></ul></ul>
  6. 6. Contaminants and Target Cleanup Goals <ul><li>In accordance with the Record of Decision (ROD), the primary objective of the removal action was to remove contaminated sediments from this site and thereby protect the public health and the environment from actual or threatened releases of pollutants, contaminants, or hazardous substances. </li></ul>
  7. 7. Contaminants and Target Cleanup Goals <ul><ul><ul><ul><li>All units in milligrams per kilogram (mg/Kg) </li></ul></ul></ul></ul>720 Zinc 13.7 Silver 0.926 Selenium 1.52 Mercury 173 Lead 184 Cadmium 0.931 Total chlordane 0.0648 Total DDT 0.35 Total PCBs Sediments 23,000 Zinc 390 Silver 390 Selenium 23 Mercury 150 Lead 37 Cadmium 1.6 Total chlordane 1.7 DDT 1.7 DDE 2.4 DDD 0.22 Total PCBs Berm Soils
  8. 8. Removal Action <ul><li>Pre-construction Activities </li></ul><ul><li>Pre-construction surveys </li></ul><ul><li>Permitting and notification </li></ul><ul><li>Securing base access </li></ul><ul><li>Pre-construction sampling </li></ul><ul><li>Pre-mobilization conference </li></ul><ul><li>Subcontracting and procurement </li></ul><ul><li>Sediment and soil sampling to pre-characterize the material for excavation, waste classification, and disposal </li></ul>
  9. 9. Removal Action <ul><li>Site Preparation Activities </li></ul><ul><li>Setup of temporary support facilities and fencing </li></ul><ul><li>Setup of erosion and sediment control measures to minimize potential impacts from stormwater discharges </li></ul><ul><li>Construction of a sediment stockpile area and dewatering facilities </li></ul><ul><li>Setup of tarping and decontamination stations for trucks that transport waste to off-site facilities </li></ul><ul><li>Construction of turnouts to accommodate the construction vehicles </li></ul>
  10. 10. Removal Action <ul><li>Excavation Activities </li></ul><ul><ul><li>Surface water removed to facilitate sediment dewatering and ease in transport </li></ul></ul><ul><ul><li>Excavation of sediments, soils, and debris in areas where concentrations of COECs exceeded TCGs </li></ul></ul><ul><ul><li>Excavated materials were transported to the stockpile area and segregated according to waste classification (based on pre-excavation sampling results) </li></ul></ul><ul><ul><li>Approximately 68,000 cubic yards of sediments were excavated and disposed of off site </li></ul></ul>
  11. 11. Excavation of Northern Channel with Long Reach Excavator
  12. 12. Removal Action <ul><li>Site Restoration Activities </li></ul><ul><ul><li>Removal of the by-pass systems from the dewatering process </li></ul></ul><ul><ul><li>Final grading of the haul road </li></ul></ul><ul><ul><li>Grading of the debris pile and stockpile areas </li></ul></ul><ul><ul><li>Security fence replacement </li></ul></ul><ul><ul><li>Asphalt road repairs </li></ul></ul><ul><ul><li>Hydroseeding the excavated berm areas with a California native seed mix </li></ul></ul>
  13. 13. Removal Action <ul><li>Confirmation Sampling </li></ul><ul><ul><li>After excavation, confirmation samples were collected and analyzed to ensure that the sediments had been adequately removed </li></ul></ul><ul><ul><li>In most cases, confirmation sampling showed that materials underlying the excavated materials met the TCGs </li></ul></ul><ul><ul><li>In instances where TCGs were exceeded, additional excavation and resampling were conducted until TCGs were met </li></ul></ul><ul><ul><li>Confirmation sampling revealed that TCGs were met in all cases with the exception of selenium, which exceeded its TCG in clays underlying the removed sediment </li></ul></ul>
  14. 14. Re-vegetation of Northern Channel Slope
  15. 15. Current Site Status <ul><ul><li>Approximately 68,000 cubic yards of sediments were removed and disposed of at appropriate facilities </li></ul></ul><ul><ul><li>All demobilization and pre- and final inspection activities have been carried out </li></ul></ul><ul><ul><li>All temporary site facilities and field equipment have been removed </li></ul></ul>The removal action at Site 27 was completed as planned Excavation work and site restoration activities at Site 27 to date:
  16. 16. Remedial Action Completion Report <ul><li>Following the removal action, the Navy began preparation of a remedial action completion report (RACR) for site closeout. </li></ul><ul><ul><li>July- August 2007 – Navy met with agencies to discuss selenium at Site 27 which exceeded its TCG in clays underlying the removed sediment </li></ul></ul><ul><ul><li>September 2007 – February 2008 – Preparation of the RACR and a Selenium Technical Memorandum </li></ul></ul>
  17. 17. RACR Update <ul><li>Selenium Technical Memorandum (TM) </li></ul><ul><ul><li>A Technical Memorandum was prepared to address selenium in the underlying clays. Findings are summarized as follows: </li></ul></ul><ul><ul><ul><li>Selenium has not been identified as ever having been used at the site </li></ul></ul></ul><ul><ul><ul><li>Existing data suggest that selenium detected in the clays is naturally occurring </li></ul></ul></ul>
  18. 18. <ul><li>Selenium Considered to be Naturally Occurring (Summarized in the Tech Memo) </li></ul><ul><ul><li>Selenium occurs naturally in regional and local soils in the Moffett area </li></ul></ul><ul><ul><li>Selenium has been detected in historic soil and sediment samples at Moffett, at levels comparable with the levels detected in clay confirmation samples </li></ul></ul>RACR Update
  19. 19. RACR Status <ul><li>26 Feb 2008 - Navy prepared a Draft Remedial Action Completion Report (RACR) </li></ul><ul><li>9 June 2008 – Agencies provided comments to the Navy on the RACR and TM </li></ul><ul><li>July 2008 – Navy and Agencies developing a completion path forward for Site 27 </li></ul>

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