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. Former NAS Moffett Field
Site 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
5. Project Objectives
Supplemental 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
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6. Technical Approach
Phase 1 – Semi-quantitative Screening
Survey
To further assess the distribution of CEs and
soil lithology in the areas of interest
Phase 2 – Monitoring Well Installations &
Sampling
To fill in data gaps of the current groundwater
monitoring well network
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8. 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
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9. MIP/DSITMS System
Membrane interface probe (MIP)/ Direct sample ion-trap
mass 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>
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10. SCAPS Test Results – Former Bldg 88
General
Tier 1 SCAPS test location
Groundwater
Flow 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
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~6 to 16 ft bgs
(Fine-grained Sediment Interval)
11. SCAPS Test Results – Former Bldg 88
General
Tier 1 SCAPS test location
Groundwater
Flow 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
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~16 to 27 ft bgs
(Coarse-grained Sediment Interval)
12. SCAPS Test Results – Former Bldg 88
General
Tier 1 SCAPS test location
Groundwater
Flow Direction Tier 2 SCAPS test location
Maximum MIP/DSITMS
Response & Groundwater
and Soil Results
PCE
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~27 to 40 ft bgs
(Fine-grained Sediment Interval)
13. SCAPS Test Results – Former Bldg 88
General
Tier 1 SCAPS test location
Groundwater
Flow Direction Tier 2 SCAPS test location
Maximum MIP/DSITMS
Response & Groundwater
and Soil Results
PCE
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~40 to 56 ft bgs
(Coarse-grained Sediment Interval)
14. SCAPS Test Results – Former Bldg 88
General
Tier 1 SCAPS test location
Groundwater
Flow Direction Tier 2 SCAPS test location
Maximum MIP/DSITMS
Response & Groundwater
and Soil Results
PCE
~56 to 70 ft bgs
(Coarse & Fine-grained
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Sediment)
15. Preliminary Findings
1) SCAPS results generally correlate well with historical data
2) MIP/DSITMS detections of PCE primarily in fine-grained sediments
3) Highest MIP/DSITMS detections of TCE & DCE primarily in fine-
grained sediments
4) Vinyl chloride was not detected in any of the MIP/DSITMS samples
5) Fine-grained sediments acting as a continuing source of chemicals to
the groundwater
6) MIP/DSITMS responses are over 10-times higher than collocated
discrete depth groundwater sample results
7) Discrete depth groundwater results are 10-times lower than
estimated effective solubility limits
8) Discrete depth soil results are over 10-times lower than estimated
soil saturation concentrations
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16. Potential Well Locations
Former Bldg 88 Area
General
Groundwater
Flow 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
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17. Planned SCAPS Locations
Traffic Island Area
General
Groundwater
Flow Direction
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0 to 23 ft bgs
18. Planned SCAPS Locations
Traffic Island Area
General
Groundwater
Flow Direction
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23 to 46 ft bgs
19. Planned SCAPS Locations
Traffic Island Area
General
Groundwater
Flow Direction
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46 to 65 ft bgs
21. Field Work Timeline
Tier 2 SCAPS at Former Bldg 88 Area – Spring 2013
Tiers 1 & 2 SCAPS at Traffic Island Area – Spring 2013
Monitoring Well Installations – Summer 2013
Groundwater Sampling – Summer & Fall 2013
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22. Questions?
Point of Contact:
Scott Anderson
BRAC Environmental Coordinator
(619) 532-0938
scott.d.anderson@navy.mil
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