Site 28 Supplemental Investigation

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Presentation to the February 7, 2013, Moffett Restoration Advisory Board meeting by Neil Hey of Shaw E&I and Valerie Harris of the Navy.

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Site 28 Supplemental Investigation

  1. 1. Former NAS Moffett FieldSite 28 Supplemental Investigation Neil Hey, PG Shaw E & I, Inc. & Valerie Harris, PE Remedial Project Manager Navy BRAC PMO West RAB Meeting February 7, 2013
  2. 2. Presentation Overview Project Objectives Technical Approach Preliminary Results Remaining Work Questions 2
  3. 3. 3
  4. 4. Project ObjectivesSupplemental investigation is needed to: 1) Further delineate PCE & daughter products (TCE, DCE, & VC) in A-aquifer within & around the Former Building 88 & Traffic Island source areas 2) Confirm depth & lateral continuity of A/B-aquitard in Traffic Island Area 3) Verify depth to top of B2-aquifer in Traffic Island Area 4) Confirm whether existing well W-88-1 is screened in B2-aquifer 5) Confirm whether B2-aquifer beneath Traffic Island Area is impacted by COCs 5
  5. 5. Technical ApproachPhase 1 – Semi-quantitative ScreeningSurvey To further assess the distribution of CEs and soil lithology in the areas of interestPhase 2 – Monitoring Well Installations &Sampling To fill in data gaps of the current groundwater monitoring well network 6
  6. 6. Navy SCAPS Rig 7
  7. 7. SCAPS Probe From: U.S. Army Corps of Engineers, 2002, Cost and Performance Report for Tri-Service SCAPS MIP, January , ERDC/EL TR-02-1 8
  8. 8. MIP/DSITMS SystemMembrane interface probe (MIP)/ Direct sample ion-trapmass spectrometer (DSITMS) detector System  Semi-quantitative COC concentration data (mg/L of calibration solution)  MIP data are only considered estimates (USACE, 2002) <http://el.erdc.usace.army.mil/elpubs/pdf/trel02-1.pdf>  Results by MIP system are relative & should be verified by soil and groundwater samples (EPA, 2012) <http://www.clu-in.org/characterization/technologies/mip.cfm> 9
  9. 9. SCAPS Test Results – Former Bldg 88General Tier 1 SCAPS test locationGroundwaterFlow Direction Tier 2 SCAPS test location µg/Lcs denotes micrograms per liter of DSITMS calibration solution 11.1 ft bgs 210,000 µg/Lcs – MIP 440 µg/L - GW Maximum MIP/DSITMS 11.5 ft bgs 0.45 mg/kg - Soil 830,000 µg/Lcs – MIP Response & Groundwater 660 µg/L - GW 8.8 mg/kg - Soil and Soil Results PCE 10 ~6 to 16 ft bgs (Fine-grained Sediment Interval)
  10. 10. SCAPS Test Results – Former Bldg 88General Tier 1 SCAPS test locationGroundwaterFlow Direction Tier 2 SCAPS test location µg/Lcs denotes micrograms per liter of DSITMS calibration solution 18 ft bgs 50,000 µg/Lcs – MIP Maximum MIP/DSITMS 78 µg/L - GW 1.9 mg/kg - Soil Response & Groundwater and Soil Results PCE 11 ~16 to 27 ft bgs (Coarse-grained Sediment Interval)
  11. 11. SCAPS Test Results – Former Bldg 88General Tier 1 SCAPS test locationGroundwaterFlow Direction Tier 2 SCAPS test location Maximum MIP/DSITMS Response & Groundwater and Soil Results PCE 12 ~27 to 40 ft bgs (Fine-grained Sediment Interval)
  12. 12. SCAPS Test Results – Former Bldg 88General Tier 1 SCAPS test locationGroundwaterFlow Direction Tier 2 SCAPS test location Maximum MIP/DSITMS Response & Groundwater and Soil Results PCE 13 ~40 to 56 ft bgs (Coarse-grained Sediment Interval)
  13. 13. SCAPS Test Results – Former Bldg 88General Tier 1 SCAPS test locationGroundwaterFlow Direction Tier 2 SCAPS test location Maximum MIP/DSITMS Response & Groundwater and Soil Results PCE ~56 to 70 ft bgs (Coarse & Fine-grained 14 Sediment)
  14. 14. Preliminary Findings1) SCAPS results generally correlate well with historical data2) MIP/DSITMS detections of PCE primarily in fine-grained sediments3) Highest MIP/DSITMS detections of TCE & DCE primarily in fine- grained sediments4) Vinyl chloride was not detected in any of the MIP/DSITMS samples5) Fine-grained sediments acting as a continuing source of chemicals to the groundwater6) MIP/DSITMS responses are over 10-times higher than collocated discrete depth groundwater sample results7) Discrete depth groundwater results are 10-times lower than estimated effective solubility limits8) Discrete depth soil results are over 10-times lower than estimated soil saturation concentrations 15
  15. 15. Potential Well Locations Former Bldg 88 AreaGeneralGroundwaterFlow Direction New Monitoring Well 11.1 ft bgs 210,000 µg/Lcs – MIP 440 µg/L - GW 11.5 ft bgs 0.45 mg/kg - Soil 830,000 µg/Lcs – MIP 660 µg/L - GW 8.8 mg/kg - Soil 16
  16. 16. Planned SCAPS Locations Traffic Island Area General Groundwater Flow Direction 17 0 to 23 ft bgs
  17. 17. Planned SCAPS Locations Traffic Island Area General Groundwater Flow Direction 18 23 to 46 ft bgs
  18. 18. Planned SCAPS Locations Traffic Island Area General Groundwater Flow Direction 19 46 to 65 ft bgs
  19. 19. Planned Well Locations Traffic Island Area 20
  20. 20. Field Work TimelineTier 2 SCAPS at Former Bldg 88 Area – Spring 2013Tiers 1 & 2 SCAPS at Traffic Island Area – Spring 2013Monitoring Well Installations – Summer 2013Groundwater Sampling – Summer & Fall 2013 21
  21. 21. Questions? Point of Contact: Scott Anderson BRAC Environmental Coordinator (619) 532-0938 scott.d.anderson@navy.mil 22

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