EBC Site Remediation & Redevelopment Program:
Mass DEP Reopening
Old Trichloroethylene (TCE) Sites
Environmental Business Council of New England
Energy Environment Economy
Welcome
Jon Kitchen
Chair, EBC Site Remediation &
Redevelopment Committee
Senior Project Manager, Civil & Environmental Consultants, Inc.
Environmental Business Council of New England
Energy Environment Economy
Program Introduction & Overview
Ed Van Doren
Program Chair
Principal Environmental Engineer
CDM Smith
Environmental Business Council of New England
Energy Environment Economy
Checking In On Sites with Residual
TCE – Why & How
Paul Locke
Assistant Commissioner
Massachusetts Department of Environmental
Protection
Environmental Business Council of New England
Energy Environment Economy
The Legalities: Understanding How
MassDEP Can Reopen a Closed Site?
Elizabeth F. Mason
Attorney
McLane Middleton
Environmental Business Council of New England
Energy Environment Economy
Trichloroethene Vapor Intrusion Assessment
– Case Study for an Industrial Facility in
Massachusetts
Pamela O. Fahey
Senior Environmental Scientist
CDM Smith
November 2017
MassDEP Trichloroethene Vapor Intrusion Assessment
Case Study for Industrial Facility in Massachusetts
Pam Fahey
Erika Parsons
Ed Van Doren
Introduction
MassDEP contacted the facility due to a change in the TCE groundwater GW-2 standard.
MassDEP called the facility to discuss reopening of TCE sites and requested a vapor intrusion assessment of the facility and the adjacent residences.
MassDEP sent a letter identifying the facility as the site PRP
PRP was required to either perform an indoor air assessment or the MassDEP would do it.
8
TCE Standard Changes
9
Year Activity
1985-1987 EPA releases TCE toxicity values in IRIS – used by states to set groundwater standards to protect public health
1988 MassDEP develops TCE groundwater standard – 300 ppb
1989 EPA withdraws TCE toxicity values from IRIS due to uncertainty with scientific studies
2000 The site completes groundwater remediation, meets MassDEP standard of 300 ppb
2011 EPA releases new toxicity values, much lower than before, including new chronic RfC that is used to assess short term inhalation exposures
2014 MassDEP lowers TCE GW-2 groundwater standard – 5 ppb
2016 MassDEP searches database for all sites that had or have TCE levels greater than the new standard of 5 ppb
TCE in Residential and Workplace Indoor Air
10
Employee and Community Outreach/Risk Communications
CDM Smith met with local facility management group to bring them up to speed regarding the letter
Together we prepared and addressed three employee all hands meetings
The local facility manager and CDM Smith met with neighbors Letters with access agreements
Final letter with sampling summary
Local health agent also informed
11
Vapor Intrusion Assessment Activities
Sub-slab soil gas sampling and analysis
Indoor air sampling and analysis
Ambient air sampling and analysis
Interview with facility health and safety manager to inventory chemicals used in facility
MassDEP did not allow groundwater sampling as the only means of vapor intrusion assessment
12
Facility Sub-Slab Soil Gas Sampling
13
Facility indoor air sampling
14
Residential sub-slab soil gas and indoor air sampling
15
Challenges associated with the residential evaluations
Very old structures 1735 to mid 1800s.
Dirt and concrete floors.
Multi-level living spaces.
Storage of consumer chemical products.
16
Facility Assessment Results Soil Gas: TCE was detected in CDM-SG-4 at 1,730 µg/m3,
greater than C/I screening level of 120 µg/m3
Indoor Air: TCE was not detected in any indoor air samples Secure building foundation
HVAC system
Trans-1,2-DCE Detected in soil gas CDM-SG-3 at 3,810 µg/m3 , greater than C/I
screening level of 3,700 µg/m3
Detected in all indoor air samples (252 µg/m3 to 5,000 µg/m3)
C/I indoor air screening level is 53 µg/m3
Disclosed prior to sampling that it is in a degreaser used at the facility 17
Residential Assessment Results
TCE was not detected in indoor air at any residence – NO VI
Carbon tetrachloride detected in each home at or slightly above residential limit of 0.54 µg/m3 (background-based value) Non-detect in all subsurface soil gas samples Present in ambient air at 0.554 µg/m3
Residential concentrations ranged from 0.554 µg/m3 to 0.749 µg/m3
Residential Basement Basement full of paints, solvents, sprays 1,1,1-TCA detected in basement at 12 µg/m3 (limit is 3 µg/m3)
Likely impacting first floor (1.31 µg/m3), subsurface (3.09 µg/m3), sub-slab (5.67 µg/m3)
18
Conclusions and Follow-up
Additional indoor air sampling event completed at facility in winter 2017 MassDEP agreed to only indoor air sampling at the facility No additional sub-slab soil gas sampling
No vapor intrusion at residences
No additional sampling at the residences
Abandonment of sub-slab soil gas sampling points at the residences in fall 2016 and at the facility in the spring 2017
19
Reports and Submittals
Submitted scopes of work for MassDEP review.
MassDEP rejected proposed groundwater sampling
Focus solely on indoor air concentrations
Complete report with results of sub-slab soil gas and indoor air sampling and assessment.
Individual letters to each of the home owners with each with laboratory results and a summary table.
No final written approval expected from MassDEP.
20
Project Management
Work was performed by the PRP MassDEP required initial sampling be completed within 60
days of initial letter
CDM Smith prepared Work Plan, communications, sampling and reporting
Direct communication with local facility management
Corporate communications support
21
Regulatory Environment
Massachusetts Contingency Plan (MCP)/Licensed Site Professional (LSP) compliance and support
Current Status under the MCP
22
Environmental Business Council of New England
Energy Environment Economy
Vapor Intrusion or How I Learned to
Stop Worrying and Love Indoor Air
Julianna Connolly & Todd Creamer
Geosyntec Consultants
Vapor Intrusion or: How I Learned to Stop
Worrying and Love Indoor Air
Julianna Connolly, LSP & Todd N. Creamer Boston, MA | 02 November 2017
25
TCE Sites & the MCP
Residential Commercial
No Significant Risk
2 µg/m3
8.8 µg/m3
Imminent Hazard – Women (pregnant or who may become pregnant)
>6 µg/m3
>24 µg/m3
Imminent Hazard – All Receptors
>20 µg/m3
>80 µg/m3
• risk-based concentrations are low
• No Significant Risk & Imminent Hazard concentrations are similar
• harder to close TCE sites with active vapor intrusion mitigation
• shutdown tests are important & often misunderstood
TCE Screening Levels from 25 US Jurisdictions
26
Common Management Strategy
Sample:
• Indoor air
• Sub-slab soil gas
Get confusing result
Sample again
27
Recommended Management Strategy
1. Exposure Assessment
2. Risk Communication
3. Timely Mitigation
28
Tell a Coherent Story
1. Exposure Assessment
2. Risk Communication
3. Timely Mitigation
29
Temporal & Season Variability: Building Pressure Control
30
Spatial Variability in Large Buildings
100 ft
Site investigation plan
31
Managing Spatial Variability: High Volume Sub-slab Sampling (HVS)
Fan or Vacuum
Sample Port
Extraction Point
Lung Box
32
Generalized CSMs for HVS
33
Background Sources
34
Distinguishing Background from VI: Field Methods
All are best when used to test
specific CSM hypotheses.
35
Satisfying to stakeholders when
you can ID a source.
Distinguishing Background from VI: Office Method
36
1.E-03
1.E-02
1.E-01
1.E+00
1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05
Att
en
ua
tio
n F
ac
tor
Subslab Soil Gas Concentration (ug/m3)
1.E-04
1.E-03
1.E-02
1.E-01
1.E+00
1.E+01
1.E+00 1.E+01 1.E+02 1.E+03A
tte
nu
ati
on
Fa
cto
r
Subslab Soil Gas Concentration (ug/m3)
TCE
111TCA
PCE
cis12DCE
11DCA
11DCE
PCE
111TCA
TCE
FREON
1. Exposure Assessment
2. Risk Communication
3. Timely Mitigation
37
• Meet with stakeholders
• Listen
• Newsletter
• Website
• Phone hotline
• Listen
• Develop a plan
Management Strategy
1. Exposure Assessment
2. Risk Communication
3. Timely Mitigation
38
Management Strategy
Rapid Response Indoor Air Treatment
• Remove ~10-50% of VOCs
• Occupants report “fresher air”
• ~$1000 each
• Quiet fan
• Low electric consumption
• Carbon life weeks – couple years
• ~300-600 cfm:
– IAExch 4-48/day
Sources:
www.austinair.com
http://amaircare.com
www.airpura.com
www.allerair.com
39
Timely Mitigation
HVAC systems
• Added makeup air
• Pressure manipulation
• Watch for re-entrainment
40
• Use existing infrastructure
Targeted Mitigation is More Timely
100 ft
Conceptual mitigation
plan
41
Summary
1. Exposure Assessment
2. Risk Communication
3. Timely Mitigation
42
1. Tell Coherent Story
– Manage temporal & spatial variability
– Background sources
2. Meet, Listen, Outreach
3. Timely Mitigation
– Carbon units
– HVAC mods
– Use existing infrastructure
– Targeted SS venting
EBC Site Remediation & Redevelopment Program:
Mass DEP Reopening
Old Trichloroethylene (TCE) Sites