Vapor Intrusion Risk Pathway: Regulatory Updates
Soil Vapor Sampling Issues
Indoor Air Sampling Issues
Blayne Hartman
Hartman Environmental Geoscience
Suzie Nawikas
Dave Balkenbush
H&P Mobile Geochemistry
February 2017
CA-CUPA
Presentation Topics
• Comparison of CA & EPA Guidances
• New Issues in CA VI Guidances
• Short Term TCE Monitoring Update
• Practical Aspects of Conducting Soil
Vapor Investigations (with Hands-On
Demonstrations)
– Soil vapor probe installation issues
– Soil vapor sampling issues
– Indoor air sampling
VI Topics:
PCE & TCE
CA Agencies
• CA-DTSC/HERO
– VI Guidance (10/2011) & Soil Gas Advisory (6/2015)
– New PCE Values (Hero Note 17, Oct 2016)
– Which AF to Use? (Some PMs have asked to use VISL)
• EPA Region 9
– Adopted Higher Value for PCE – oops, but not on CA sites
– Using default attenuation factor of 0.03 for all structures!!!
• SF-RWQCB
– ESLs updated in early 2016, 25x higher than DTSC for SS
– ESLs updated in early 2016, 15x higher than EPA for SS
PCE Comparison
• Residential Indoor Air (1e-6)
– EPA : 11 ug/m3
– DTSC: 0.46 ug/m3 (down from 0.48) – 4% change
• Industrial Indoor Air (1e-6)
– EPA: 47 ug/m3
– DTSC: 2.0 ug/m3 (down from 2.1) – 5% change
~ 24x Lower than Fed EPA
Soil Gas Allowed Levels
PCE in Soil Gas, Residential Receptor (1e-6 risk)
RBSL (ug/m3)
DTSC Sub-slab 9.2
SF-RWQCB Sub-slab 240
EPA Sub-slab 367
DTSC – 5’ soil gas 230
SF-RWQCB – 5’ soil gas 240
EPA – 5’ soil gas 367
Big Difference in SS, but not SG
TCE Comparison - Chronic
• Residential Indoor Air (1e-6)
– EPA : 0.48 ug/m3
– SF-RWQCB: 0.48 ug/m3
– DTSC: 0.48 ug/m3
• Commercial Indoor Air (1e-6)
– All Same: 2.1 ug/m3 (non-cancer)
Note: TCE not listed in July 2016
Hero Note 3 Table??
Soil Gas Allowed Levels
TCE in Soil Gas, Residential Receptor (1e-6 risk)
RBSL (ug/m3)
DTSC Sub-slab 9.6
EPA Sub-slab 16
SF-RWQCB sub-slab 240
DTSC – 5’ soil gas 240
EPA – 5’ soil gas 16
SF-RWQCB – 5’ soil gas 240
Big Difference in both SG and SS
Soil Gas Allowed LevelsBenzene, Residential Receptor, 1e-6 Risk
RBSL (ug/m3)
EPA OSWER @ Sub-slab & 5’ 11.7
DTSC Subslab 1.9
SF-RWQCB Subslab & 5’ 48
EPA OUST (from Ch 12, Fig 9) 3,100,000
CA Low-Risk Policy: O2>4% 85,000
CA Low-Risk Policy: O2<4% 85
OSWER ~300,000 times lower than OUST!!
VI Regulatory Topic:
Short Term TCE Exposure
EPA R7 Short Term TCE Guidance
• EPA Region 7, November 2nd, 2016
– "It is assumed that an exposure to TCE at any time during
an approximate three-week period in early pregnancy could
result in one or more types of cardiac malformations.”
– 2 ug/m3 – 24 hour period (residential)
– 6 ug/m3 – 8 hour (commercial)
• Does this mean the following:
– 48 ug/m3 – for 1 hour?
– 96 ug/m3 – for 30 minutes?
– 480 ug/m3 – for 6 minutes?
Short-Term TCE Assessment Options
• Passive Collectors
– Incorrect exposure time for businesses/schools
– No resolution; 1 number over sampling period
Subject to false positives
Subject to false negatives
– Expensive if multiple rooms, multiple events
– No real-time feedback
• Continuous Analyzers
No resolution for short term exposures (days)
0
0.5
1
1.5
2
2.5
3
3.5
4
0 50 100 150 200 250 300 350 400 450 500 550 600
Co
nc
(ug
/m
3)
Run Number
PCE - 420 1st Floor Air
PCE
Indy Duplex - Short-Term “Facts"
12/2012 3/20131/2013 2/2013
~24 hours
21 days (ave=0.5 ug/m3)
Continuous Monitoring System
Sample Inlets12” High
0
50
100
150
200
250
300
350
400
450
500
0 50 100 150 200 250 300 350 400 450
tce
Large Manufacturing Building
Same Time Every
Day
Large Industrial FacilitySVE Remedial Confirmation
Pre-SVE
Active-SVE
Residential Monitoring
0
1
2
3
4
5
6
7
8
9
0 48 96 144 192 240 288 336
TCE(ug/m3)MasterBedroomvs.Run#
Air Filtration Units
9/12/16 9/24/16 10/16/16
SSD On SSD Off
OnOff
Run #
0
2
4
6
8
10
12
14
16
18
0 10 20 30 40 50 60 70 80 90 100
Room103IndoorAir- TCE(ug/m3)
Room Closed:17:00
Door Opened
8:00 am
Door Closed
8:20 am
ug/m3
Forthcoming VI Events
• 2-Day VI Course – California– Oakland: Feb 28 & March 1
– Orange County: March 2 & 3
– www.hartmaneg.com for more info
• AEHS Conf – San Diego: March 2017
– EPA OSWER All Day Workshop (Tues)
– All Day VI Session/Presentations (Wed & Thurs)
