Zimmerman, J., B. Schumacher, C. Lutes, B. Cosky, R. Truesdale and B. Schumacher “ORD VI-research duplex and Wheeler Building, Indianapolis- summary of evidence to date: temporal variability in long-term mitigation performance and before mitigation: What causes it?” Presented at AEHS/EPA 2015 workshop on Long-Term Evidence-Based Protection & Sustainability; in Residential, Commercial and Industrial Buildings; San Diego.

1. Office of Research and Development
National Exposure Research Laboratory
ORD VI-Research Duplex and
Wheeler Building, Indianapolis-
Summary of Evidence to Date:
Temporal Variability in Long-term
Mitigation Performance and Before
Mitigation: What Causes It?
Presented at EPA 2015 workshop on Long-Term Evidence-Based Protection &
Sustainability; in Residential, Commercial and Industrial Buildings
John Zimmerman and Brian Schumacher US EPA NERL
Christopher Lutes CH2M HILL
Brian Cosky ARCADIS Inc.
Robert Truesdale and Robert Norberg
RTI International
420 Not
Heated
422
Heated

2. 2 11 January 2020
Duplex Synopsis
Indoor and Ambient Air, Passive Samples
Subslab and Soil Gas, Active Samples
• Locations: ambient; basement & first floor each side
• 131 rounds of VOC sampling: (Jan 2011-Dec
2014): 1-4 week intervals VOCs by Radiellos
• Five internal soil gas locations, 4 depths
each (6, 9, 13, and 16.5 ft).
• Five conventional sub-slab locations.
• Four basement wall ports.
• As many as 110 different days of subslab
sampling
Groundwater
• Multi-depth, short screen wells on two sides of
duplex
• Single depth well completed through basement

3. 3 11 January 2020
Mitigation Performance and
Temporal Variability: PCE
0.01
0.1
1
10
100
01‐Jan‐11
02‐Jul‐11
01‐Jan‐12
02‐Jul‐12
01‐Jan‐13
02‐Jul‐13
01‐Jan‐14
03‐Jul‐14
Concentration (µg/m3)
Date
Indoor Air PCE (Passive Sampler Data)
422 First PCE
422 Base S PCE
420 Base S PCE
Ambient PCE
Mitigation On
Mitigation Passive
Mitigation On
Mitigation Passive
Mitigation imperfect
and variable in
initial on-off tests
Same mitigation
system reduced
concentrations to
ambient in long term
test; less variability < 1
OOM
~ 2 Orders of
Magnitude
unmitigated
temporal
variability

4. 4 11 January 2020
Mitigation Performance and
Temporal Variability - Chloroform
0.01
0.1
1
10
100
01‐Jan‐11
02‐Jul‐11
01‐Jan‐12
02‐Jul‐12
01‐Jan‐13
02‐Jul‐13
01‐Jan‐14
03‐Jul‐14
Concentration (µg/m3)
Date
Indoor Air Chloroform (Passive Sampler Data)
422 First Chloroform
422 Base S Chloroform
420 Base S Chloroform
Ambient Chloroform
Mitigation On
Mitigation Passive
About 1.5 Orders of
Magnitude
Unmitigated
temporal variability Mitigation Performance Better
When Treatment Sustained – Low
Long Term Variability

5. 5 11 January 2020
Radon Temporal Variability With and Without
Mitigation – High Resolution Data with
Multiple Averaging Times
Long-term Trend With and Without Mitigation
Blow-up of Long-term Mitigation Period
1/7-1/10/15 saw 4 day Radon peak; with
daily lows as low as -7 F and wind speeds
averaging 18 MPH and Max 32 MPH
Period Blown
Up Below

6. Wheeler Building Mitigation:
History
6
• 100,000 square foot building
• Industrial facility from 1911 until 1995.
• Renovations into live-work lofts, office
space and a theater.
• EPA Research measurements 2009
• Sealing and SSD mitigation system
was installed in 2010 – designed to
address highest concentration portion.
• Subslab VOCs a mix of releases here
and upgradient. Premitigation subslab
up to 12,000 µg/m3 TCE
• Regulator required one round of initial proof of effectiveness through VOC
testing (1/11) and differential pressure, then system operation by owner
(2011-now)
• Intensive resampling for 6 months; with 2 week passive winter 2013-2014

7. 7
0.1
1
10
9/9/2008
1/22/2010
6/6/2011
10/18/2012
3/2/2014
Concentration (µg/m3)
Date
TCE in Indoor Air at Wheeler Building, Pre‐ and Post‐mitigation
North End of Wheeler Building A
North End Wheeler Bldg B
First Floor Prop Room
Post‐mitigation Building A
Post‐mitigation Building B
Post‐mitigation Prop Room
Mitigation Start
Indiana 30 Year Residential TCE Action Le

8. Frequently Asked Questions
about Duplex Study
• What is the role of preferential pathways, including
sewer lines, in this data set?
• Are the features of this duplex and other well studied
cases “typical” of the US housing inventory?
• Is the VOC mass observed entering the duplex
primarily from groundwater or vadose zone sources?
• Why do chloroform and PCE differ at this site, in terms
of sources and VI behavior?
• What is the spatial and temporal variability of the
observed attenuation factors?
8

9. 9
What is the role of preferential pathways,
including sewer lines, in duplex data set?

10. 10
What is the
role of
preferential
pathways,
including
sewer lines, in
duplex data
set?

11. PCE Soil Gas Spatial Distributions
11
December
2011
August
2011
January
2011

12. What is the role of preferential
pathways, including sewer
lines, in duplex data set? –
Results before drain sealing
12
Passive Drain Sampling Data April 13–April 21, 2011 (µg/m3
)
Location Chloroform TCE PCE
422 laundry drain – 1st floor 320 5.6 310
422 bathroom—in sink 1.2 0.089 1.4
422 basement floor drain (near
furnace) 0.65 0.091 1.7
420 bathroom—in sink 1.5 0.054 0.96
420 laundry room drain in floor 1.6 0.087 2.6

13. What is the role of preferential
pathways, including sewer lines, in
duplex data set?
• Helium Tracer Test
–horizontal migration toward the building over distances of up
to 20 ft
–rapid vertical migration from 13 ft to 6 ft. bgs at the injection
cluster; typically within 2 days, with and without mitigation.
• Ground Penetrating Radar (GPR) Survey
–concrete slab varies from 0.5 to 0.7 ft in thickness
–irregular undulating contact with the underlying fill material
resulting in voids where soil gas may pool or move
preferentially.
13

14. What is the role of preferential
pathways, including sewer
lines, in duplex data set?
• Sewer lines and laterals appeared to play some role in contaminant fate
and transport in this system; but we have to distinguish multiple scales.
• Based on the location of the highest PCE concentrations and sewers we
suspect they play a role in neighborhood scale transport but we haven’t
sampled off our lot.
• Based on the contaminant distribution under the house we suspect that
the sewer lateral may have a role in moving mass from the street toward
the house.
• Elevated concentrations of PCE and chloroform were present in the
headspace of sewer gas but primarily in one leg; early in the project.
• Their role as a direct entry pathway through the building envelope were
minimized by sealing the drains.
14

15. Are the features of this duplex and
other well studied cases “typical”
of the US housing inventory?
Compare Indianapolis Duplex and Sun-devil Manor to the
2013 American Housing Survey results (% of 128K units):
• Location
– Duplex - Central city (30%)
–Sun-Devil – In MSA but not Central City (50%)
• Public Sewer - both Duplex and Sun Devil – yes (81%)
• Units in structure
– Duplex = 2 to 4 units (8%)
–Sun-Devil = 1 detached unit (65%)
• Construction date – Median in U.S. is 1975
–Duplex = Pre 1915 (Pre 1919 is 7% of housing stock)
–Sun Devil =1991 (1985 to 1995 is 12% of housing stock)
15

16. Are the features of this duplex and
other well studied cases “typical”
of the US housing inventory?
• Foundation (survey is % of single family for this variable):
–Duplex, Basement (full or partial basement = 42%)
–Sun-Devil – Concrete Slab Split Level (slab = 34%)
–Crawl space (22%)
• Heating – Both Forced Hot Air – (64%)
• Cooling
–Duplex – window units (21%)
–Sun-Devil – central air (65%)
• Physical Problems – 5% of units have moderate to severe
problems in one census category
–Duplex – Moderate upkeep problems
–- Sun Devil – no problems
16

17. 17
Is the VOC mass
entering from
groundwater or
vadose zone
sources?:
Henry’s Law
Comparison
Chloroform and
PCE: Different
Behavior?

18. Is the VOC Mass Entering Primarily From
Groundwater or Vadose Zone Sources?:
Groundwater Time Sequence
18
Chloroform and
PCE: Different
Behavior?

19. Is VOC Mass From Groundwater or
Vadose Zone?: Soil Gas Time
Sequence
50
500
5000
Jan‐10
Jul‐10
Jan‐11
Jul‐11
Jan‐12
Jul‐12
Jan‐13
Jul‐13
Jan‐14
Concentration (µg/m3)
Subslab Port PCE
SSP‐1 PCE
SSP‐4 PCE
Mitigation
On
Mitigation
Passive

20. What is the
spatial and
temporal
variability of
attenuation
factors?: Daily
(On-line GC
Data)
20

21. What is the
spatial and
temporal
variability of
attenuation
factors?:
Weekly
(Passive
Sampler and
TO-17 Data)
21

22. Conclusions
• Long term mitigation test at the duplex showed that the
commercially installed mitigation system worked well in the
long term for VOCs; although we observed some short term
spikes in concentration.
• Six months of continuous monitoring at Wheeler showed that
a commercial mitigation system on a large mixed use building
was providing good protection after 3 years of building owner
operations.
• Sewer line is likely playing a role in transport on the
neighborhood and lot scales at the duplex although the
building envelope is sealed off. 80% of US homes have
sewers.
• Based on the American Housing survey the two well studied
cases are reasonably representative.
22

23. Conclusions - Continued
• PCE at the duplex is likely arriving on the property from
groundwater depth; but variability in groundwater
concentrations does not explain the subslab and indoor
variability observed. Mass storage in vadose zone soils
may play an important role. Temperature differential was
shown to be quite significant in our time series analyses.
• Chloroform likely has a shallow source, perhaps
municipal water/sewer; but may be “stripped” on the way
down to the water table.
• Average attenuation factors at the duplex vary only
modestly over time.
23

24. More Available: Four Reports
• Fluctuation of Indoor Radon and VOC Concentrations Due
to Seasonal Variations EPA/600/R-12/673; September
2012 (Been Available)
• Assessment of Mitigation Systems on Vapor Intrusion:
Temporal Trends, Attenuation Factors, and Contaminant
Migration Routes under Mitigated and Non-mitigated
Conditions; EPA/600/R-13/241 (Release expected 3/15)
• Simple, Efficient, and Rapid Methods to Determine the
Potential for Vapor Intrusion into the Home: Temporal
Trends, Vapor Intrusion Forecasting, Sampling Strategies,
and Contaminant Migration Routes EPA/600/R-14/397
(Release expected 3/15).
• Future plan will focus on peer reviewed papers – first two
on Long Term Mitigation and Improved Passive Sampler
Performance
24

25. Contact and Acknowledgements
• Christopher.lutes@ch2m.com,
• rst@rti.org or
• Zimmerman.JohnH@epa.gov
• The authors thank:
–U.S. EPA ORD National Exposure Research Laboratory (NERL),
– Leigh Evans, Doressa Breitfield, and Nate Lichti; Mapleton-Fall Creek
Development Corporation
– Alan Williams and Dale Werkema, US EPA
– Heidi Hayes and Ausha Scott; Eurofins/Air Toxics Ltd.
– Robert Uppencamp, Nadine Weinberg, & Rebecca Forbort, ARCADIS
– David Eskew, OTIE