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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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Former NAS Moffett Field
Neil Hey, PG
Shaw E & I, Inc.
&Valerie Harris, PE
Remedial Project Manager
Navy BRAC PMO West
RAB Meeting
February 7, 2013
Site 28 Supplemental Investigation
Presentation Overview
2
Project Objectives
Technical Approach
Preliminary Results
Remaining Work
Questions
3
Supplemental investigation is needed to:
1) Further delineate PCE & daughter products (TCE,DCE, & VC) in A-aquifer within & around the FormerBuilding 88 & Traffic Island source areas
2) Confirm depth & lateral continuity of A/B-aquitard inTraffic Island Area
3) Verify depth to top of B2-aquifer in Traffic IslandArea
4) Confirm whether existing well W-88-1 is screened inB2-aquifer
5) Confirm whether B2-aquifer beneath Traffic IslandArea is impacted by COCs
Project Objectives
5
Phase 1 – Semi-quantitative ScreeningSurvey
To further assess the distribution of CEs andsoil lithology in the areas of interest
Phase 2 – Monitoring Well Installations &Sampling
To fill in data gaps of the current groundwatermonitoring well network
Technical Approach
6
Navy SCAPS Rig
7
SCAPS Probe
8
From:
U.S. Army Corps of Engineers, 2002,
Cost and Performance Report for Tri-Service
SCAPS MIP, January , ERDC/EL TR-02-1
Membrane 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 beverified by soil and groundwater samples(EPA, 2012)
<http://www.clu-in.org/characterization/technologies/mip.cfm>
MIP/DSITMS System
9
SCAPS Test Results – Former Bldg 88
10
Maximum MIP/DSITMSResponse & Groundwater
and Soil Results
PCE
~6 to 16 ft bgs(Fine-grained Sediment Interval)
GeneralGroundwaterFlow Direction
11.5 ft bgs830,000 µg/Lcs – MIP660 µg/L - GW8.8 mg/kg - Soil
11.1 ft bgs210,000 µg/Lcs – MIP440 µg/L - GW0.45 mg/kg - Soil
µg/Lcs denotes micrograms perliter of DSITMS calibration solution
Tier 2 SCAPS test location
Tier 1 SCAPS test location
SCAPS Test Results – Former Bldg 88
11
GeneralGroundwaterFlow Direction
18 ft bgs50,000 µg/Lcs – MIP78 µg/L - GW1.9 mg/kg - Soil
Maximum MIP/DSITMSResponse & Groundwater
and Soil Results
PCE
~16 to 27 ft bgs(Coarse-grained Sediment Interval)
µg/Lcs denotes micrograms perliter of DSITMS calibration solution
Tier 2 SCAPS test location
Tier 1 SCAPS test location
SCAPS Test Results – Former Bldg 88
12
GeneralGroundwaterFlow Direction Tier 2 SCAPS test location
Tier 1 SCAPS test location
Maximum MIP/DSITMSResponse & Groundwater
and Soil Results
PCE
~27 to 40 ft bgs(Fine-grained Sediment Interval)
SCAPS Test Results – Former Bldg 88
13
GeneralGroundwaterFlow Direction
Maximum MIP/DSITMSResponse & Groundwater
and Soil Results
PCE
~40 to 56 ft bgs(Coarse-grained Sediment Interval)
Tier 2 SCAPS test location
Tier 1 SCAPS test location
SCAPS Test Results – Former Bldg 88
14
GeneralGroundwaterFlow Direction
Maximum MIP/DSITMSResponse & Groundwater
and Soil Results
PCE
~56 to 70 ft bgs(Coarse & Fine-grained
Sediment)
Tier 2 SCAPS test location
Tier 1 SCAPS test location
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 tothe groundwater
6) MIP/DSITMS responses are over 10-times higher than collocateddiscrete depth groundwater sample results
7) Discrete depth groundwater results are 10-times lower thanestimated effective solubility limits
8) Discrete depth soil results are over 10-times lower than estimatedsoil saturation concentrations
Preliminary Findings
15
Potential Well LocationsFormer Bldg 88 Area
16
GeneralGroundwaterFlow Direction
11.5 ft bgs830,000 µg/Lcs – MIP660 µg/L - GW8.8 mg/kg - Soil
11.1 ft bgs210,000 µg/Lcs – MIP440 µg/L - GW0.45 mg/kg - Soil
New Monitoring Well
Planned SCAPS LocationsTraffic Island Area
17
GeneralGroundwaterFlow Direction
0 to 23 ft bgs
Planned SCAPS LocationsTraffic Island Area
18
GeneralGroundwaterFlow Direction
23 to 46 ft bgs
Planned SCAPS LocationsTraffic Island Area
19
GeneralGroundwaterFlow Direction
46 to 65 ft bgs
Planned Well LocationsTraffic Island Area
20
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
Field Work Timeline
21
Questions?
22
Point of Contact:
Scott Anderson
BRAC Environmental Coordinator
(619) 532-0938