EPA Vapor Intrusion Workshop Measurement-Based Methods for - - PowerPoint PPT Presentation

EPA Vapor Intrusion Workshop

Measurement-Based Methods for Protective & Defensible Chlorinated VI Exposure Determinations

35th Annual International Conference on Soils, Sediments, Water, and Energy, Amherst, Massachusetts, October 22nd, 2019

MEW/Moffett Field Buildings 15 and 17 – A Review of Multiple Published Studies; Site in IECC Climate Zone 3C

Chris Lutes, Jacobs

References

• Brenner, David. "Results of a long-term study of vapor intrusion at four large buildings at the NASA

Ames Research Center." Journal of the Air & Waste Management Association 60, no. 6 (2010): 747- 758.

• Brenner, D. and M. Walraven “Revised Human Health Risk Assessment NASA Research Park Moffett

Field, California July 28, 2003 “ https://www.sec.gov/Archives/edgar/data/1664703/000119312518190488/d96446dex106.htm

• Haley and Aldrich 2009 “Final Supplemental Remedial Investigation Report for Vapor Intrusion

Pathway Middlefield-Ellis-Whisman Study Area, Mountain View and Moffett Field, California, June. https://www.navfac.navy.mil/niris/SOUTHWEST/MOFFETT_FIELD_NAS/N00296_003903.PDF

• Haley and Aldrich 2009 “Final Supplemental Feasibility Study for the Vapor Intrusion Pathway

Middlefield-Ellis-Whisman Study Area; June 29, 2019 https://semspub.epa.gov/work/09/2324674.pdf

• Haley & Aldrich, 2011 “Site-wide Vapor Intrusion Sampling and Analysis Work Plan for Response

Action Testing” September 29. https://semspub.epa.gov/work/09/100002742.pdf

• Mactec Engineering and Consulting Inc. 2005 “Report on Long-term Indoor Air Quality Monitoring;

Buildings 15, 16, 17, 20, n-210 and N243” NASA Ames Research Center, Moffett Field California

• Mills, William B., Sally Liu, Mark C. Rigby, and David Brenner. "Time-variable simulation of soil vapor

intrusion into a building with a combined crawl space and basement." Environmental science & technology 41, no. 14 (2007): 4993-5001.

• Noreas for NAVFAC “Draft 2019 Installation Restoration Site 28 Air Sampling and Vapor Intrusion Tier

Response Evaluation Report, July 2019 https://semspub.epa.gov/work/09/100018154.pdf

Building 15

• 11,900 square foot,
• steam heated with air conditioning, two HVAC zones
• occupied 24x7
• Main portion and west wing office space; HVAC equipment and

garage in east wing

• HVAC adjusted in May 2003 to increase outside air supply, reportedly

reducing TCE in indoor air

Building 17

• 3,900 square feet first floor, 3,000 sq ft basement office building

constructed 1932-1933 with small crawlspace beneath the stairs to hold mechanical equipment

• Basement is 6 ft below grade and 2 ft above grade.
• Building 17 is steam heated and occupied during the work week on

the first floor only.

Photo reprinted from https://www.cmu.edu/cmnews/extra/030108 _growingwest.html

Conceptual Site Model (From https://rmcs-1.itrcweb.org/6-2-moffett-mew-regional-plume-california/

• USEPA. 2012f. Supplemental Sitewide Feasibility Study, Middlefield-Ellis-Whisman Superfund Study Area. USEPA Region 9.

Location of Buildings

• ver Groundwater

Plume

• IECC Zone 3C warm-marine Koppen Csb

(Mediterran)

• Buildings near each other
• Approximately at midline of plume

More Recent TCE in Soil Gas in Building 15 and 17 Vicinity

Data Set/Study Design

• A combination of 24- and 8-hr samples were collected in Buildings 15 and 17 (i.e.,

24- and 8-hr samples were not simultaneously collected from a given location at any given time)

• 8 hour samples were collected 8 AM-4 PM, 4 PM- 12AM, 12 AM to 8 AM
• 102 samples at indoor location 15-1 which was presented in the most detail, 68

samples at the background locations and 128 samples at the outdoor location near the studied buildings.

• Multiple linear regression models were used to relate indoor concentrations to

meteorological variables. Descriptive statistics were calculated by month. 8 hour sample descriptive statistics were calculated for three repetitive shifts.

• Available data included wind speed, barometric pressure, temperature, humidity,

wind direction, visibility, and precipitation.

• Groundwater data for shallow monitoring well near subject buildings also

available

• No indoor sources of target VOCs identified in database of materials used at the

facility and a walk through.

Groundwater Level Variation (from Multiple Wells)

Groundwater Concentration by Month (Max)

Temporal Variability of Indoor Air

Building 15 Station 15-1 Outdoor Station A17

Daily TCE Building 15

• Peak

primarily between September 2003 and February 2004

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 08-Jun-03 16-Sep-03 25-Dec-03 03-Apr-04 12-Jul-04

Concentration (µg/m3) Date

TCE Concentrations at Location 15-1

TCE (24-hr) TCE (8-hr)

New plot created from historical data

Maximum Daily TCE Buildings 15 and 17

• Peak between

September 2003 and February 2004

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00

30-Jun-03 02-Jul-03 08-Jul-03 10-Jul-03 14-Jul-03 16-Jul-03 18-Jul-03 22-Jul-03 24-Jul-03 28-Jul-03 30-Jul-03 01-Aug-03 05-Aug-03 07-Aug-03 11-Aug-03 13-Aug-03 15-Aug-03 19-Aug-03 21-Aug-03 25-Aug-03 27-Aug-03 29-Aug-03 03-Sep-03 05-Sep-03 09-Sep-03 11-Sep-03 15-Sep-03 17-Sep-03 19-Sep-03 23-Sep-03 25-Sep-03 01-D ec-03 09-D ec-03 16-D ec-03 22-D ec-03 07-Jan-04 13-Jan-04 20-Jan-04 26-Jan-04 06-Feb-04 12-Feb-04 20-Feb-04 25-Feb-04 04-Mar-04 11-Mar-04 19-Mar-04 24-Mar-04 01-Apr-04 08-Apr-04 16-Apr-04 22-Apr-04 30-Apr-04 05-May-04 13-May-04 19-May-04 04-Jun-04 10-Jun-04 17-Jun-04 23-Jun-04

Conc (ug/m3)

15-1 15-2 17-1 17-2 A17 B258

Note this original is a line chart not XY chart

July 03 Aug 03 Sept 03 Dec 03 Feb04 Apr 04 June 04

Daily cis-1,2- DCE Concentrations Building 15

• Peak concentrations

December 2003 to March 2004

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 08-Jun-03 16-Sep-03 25-Dec-03 03-Apr-04 12-Jul-04

Concentration (µg/m3 Date

cis-1,2-DCE Concentrations at Location 15-1

cis-1,2-DCE (24-hr) cis-1,2-DCE (8-hr)

New plot created from historical data

Maximum Daily cis-1,2- DCE Concentrations Buildings 15 and 17

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40

30-Jun-03 02-Jul-03 08-Jul-03 10-Jul-03 14-Jul-03 16-Jul-03 18-Jul-03 22-Jul-03 24-Jul-03 28-Jul-03 30-Jul-03 01-Aug-03 05-Aug-03 07-Aug-03 11-Aug-03 13-Aug-03 15-Aug-03 19-Aug-03 21-Aug-03 25-Aug-03 27-Aug-03 29-Aug-03 03-Sep-03 05-Sep-03 09-Sep-03 11-Sep-03 15-Sep-03 17-Sep-03 19-Sep-03 23-Sep-03 25-Sep-03 01-D ec-03 09-D ec-03 16-D ec-03 22-D ec-03 07-Jan-04 13-Jan-04 20-Jan-04 26-Jan-04 03-Feb-04 10-Feb-04 18-Feb-04 23-Feb-04 02-Mar-04 08-Mar-04 17-Mar-04 22-Mar-04 30-Mar-04 06-Apr-04 13-Apr-04 19-Apr-04 28-Apr-04 03-May-04 11-May-04 17-May-04 02-Jun-04 08-Jun-04 15-Jun-04 21-Jun-04

Conc (ug/m3)

15-1 15-2 17-1 17-2 A17 B258

• Peak concentrations

December 2003 to March 2004

Note this original is likely a line chart not XY chart

July 03 Aug 03 Sept 03 Dec 03 Feb04 Apr 04 June 04

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40

20 40 60 80 100 120

6/8 7/28 9/16 11/5 12/25 2/13 4/3 5/23 7/12

Concentration (ug/m3)

Exterior Temperature (F) Date

Temperature (100 point rolling average) and cis-1,2-DCE versus Time at Location 15-1

Temperature (°F) cis-1,2-DCE (24-hr) cis-1,2-DCE (8-hr) 100 per. Mov. Avg. (Temperature (°F))

• New plot created from

historical data

0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 29.4 29.6 29.8 30 30.2 30.4 30.6 30.8 31 6/8 7/28 9/16 11/5 12/25 2/13 4/3 5/23 7/12 Concentration (ug/m3) Barometric Pressure (inches of Hg) Date

Barometric Pressure and cis-1,2-DCE versus Time at 15-1

(points above 31" BP truncated, assumed to be artifacts)

Pressure ("Hg) cis-1,2-DCE (24-hr) cis-1,2-DCE (8-hr)

New plot created from historical data

Barometric Pressure and Temperature

5 10 15 20 25 30 995 1000 1005 1010 1015 1020 1025 1030 1035

6/30/2003 7/8/2003 7/14/2003 7/19/2003 7/25/2003 7/31/2003 8/6/2003 8/12/2003 8/18/2003 8/23/2003 8/29/2003 9/4/2003 9/10/2003 9/16/2003 9/22/2003 9/27/2003 12/5/2003 12/11/2003 12/17/2003 12/23/2003 1/7/2004 1/13/2004 1/19/2004 1/24/2004 2/2/2004 2/7/2004 2/13/2004 2/19/2004 2/25/2004 3/2/2004 3/8/2004 3/13/2004 3/19/2004 3/25/2004 3/31/2004 4/6/2004 4/12/2004 4/17/2004 4/23/2004 4/29/2004 5/6/2004 5/12/2004 5/18/2004 5/24/2004 5/29/2004 6/4/2004 6/10/2004 6/16/2004 6/22/2004

Temperature (C) Pressure (mbars)

Pres Temp

Building 15 Results and Conclusions from Original Paper

• For building 15 location 1 data (102 samples) are presented as box and whisker plots for each of 12

nonsequential months. The maximum monthly 95th percentile was approximately 4 µg/m3 and the minimum monthly 5th percentile was 0.2 µg/m3. The monthly median range was about 0.25 to 1.5 µg/m3

• Statistical analysis showed TCE and cis -1,2-DCE were different from background (p<0.001),

benzene was not

• “Monthly seasonal variability analysis showed that the indoor air concentration in the four subject

buildings was highest in the winter and lowest during the summer months.

• The empirical evidence presented shows that the measured indoor air concentration was related

to the outdoor air temperature and the depth to groundwater.

• Although there appears to be diurnal variation in the concentrations of the primary analytes, as

measured by the sequence of three 8-hr samples, the overall differences during the day are small and do not change the overall conclusions drawn from the 24-hr canister samples.

• Day-to-day variation over 1 month of sampling generally only varied by a small amount, typically

a factor of approximately 2.

Analysis/Conclusions from Original Paper

• “Measured indoor air concentration was further investigated by developing multiple linear

regression models that accounted for the measured meteorological conditions as reflected in the average daily outdoor air temperature, atmospheric pressure, wind speed, and wind

• direction. …
• These same four meteorological parameters had little or no effect on the measured TCE
• concentrations. At five locations (15-1, 15-2, 17-1, A17, and B258) none of the four

meteorological parameters had a significant effect on the measured concentrations.

• At the remaining five locations (17-2, 16-1, 16-2, 20-1, 20-2) the primary meteorological

parameters affecting the measured indoor TCE concentrations varied by location. Outdoor temperature and wind speed seemed to have the greatest impact on the greatest number

• f locations.
• For the infiltration pathway (benzene) and the vapor intrusion pathway (TCE), this can be

because of building depressurization (wind speed), the stack effect because of heating (temperature), or the use of natural ventilation (temperature and wind speed). However, it would appear that over the range of meteorological conditions measured during the study period, infiltration of benzene from the outdoor air was more affected by the meteor-logical conditions than vapor intrusion of TCE from the subsurface.”

Observations from New Plots

• Low temperature appears correlated with VOCs
• Possible visual associations between pressure swing events and high

VOCs

• 8 hr samples appear to show higher peak concentrations