1. Connecticut Remediation Standard Regulations: Volatilization Criteria
Things to mention: GW criteria
Soil Contribution covered under PMC (leaching potential much lower than volatilization potential from soil) – need to remediate VOCs before rendering inaccessible

2. Volatilization Criteria Applicability
Volatilization Criteria applies to groundwater within 15 feet of the ground surface (or within 15 feet beneath the lowest level of a building)
There is no horizontal component to the applicability
Things to mention: Most GW in CT within 15 feet (so will affect most locations) - ~85%
Lowest level of building means that the depth to GW needs to be considered from building foundation
Although there is no horizontal component to the applicability, the CSM for the site may require that the VI pathway needs to be investigation (part of characterization)
22a-133k-3(c)(1)&(2)

3. Risk from vapor intrusion only pertains when groundwater is polluted with VOCs at the water table – Standard wells (with representative screens bisecting the water table) are required to demonstrate compliance
ACME Inc.
MW1
MW2
MW3s+d
MW4
Basement
Basement
UST
Things to mention: Downward gradient can cause plume to sink
If plume sinks, no contaminate at surface for diffusion to occur
Need to be demonstrated with standard wells (shouldn’t use micro-screens to “fish” for clean water on top of the water table)
Need to keep in mind that all GW->SW at some point:
Where does it surface?
Is there potential for an issue further away?
Have seen it happen – went under some buildings across the street w/o indoor air issue and then resurfaced into a wetlands potentially causing an indoor air issue further away
Vertical Flow
GW flow direction
Not to Scale

4. Demonstrating Compliance with Volatilization Criteria
GW Volatilization Criteria (Primary Compliance)
SV Volatilization Criteria (Alternative Compliance)
Undertake mitigation (Exemption)
No building can be constructed (Exception)
Conduct indoor air monitoring (Exemption)
Things to mention: Iterative process – GW->Soil Vapor->Indoor Air (can break pathway at any point)
Plume must be well defined/characterized
Indoor Air Monitoring – plan needs to be laid out by a health professional. Not straightforward (many pitfalls – ventilation, breathing zones, existing uses, etc.)
Indoor Air issue exacerbated by conflicting regulations with different goals (TCE):
OSHA (100ppm)
1996 RSRs (5µg/m3) – both Res & I/C
2003/2008 Proposed (1µg/m3) – both Res & I/C
22a-133k-3(c)(1)&(3)(A)&(3)(B)&(5)(A)&(5)(B)

5. Soil Vapor Volatilization Criteria
Soil vapor samples must be collected beneath a building to be compared to the Soil Vapor Volatilization Criteria
Soil vapor samples collected outside the footprint of the building cannot be used to demonstrate compliance
Things to mention: STRESS – beneath a building
Around foundation can be used as a screening tool, but not to demonstrate compliance – not always what client desires
22a-133k-3(c)(3)(A)

6. Mitigation
Remediation of groundwater for volatilization is not required if measures acceptable to the Commissioner are taken to prevent the migration of vapors into any overlying building
Things to mention: Quick “exit ramp”
Measures acceptable means Commissioner can impose additional conditions to submitted plan – best to discuss with DEEP beforehand
Prefer to see active systems (or at least ones that can be made active) to solely passive systems (vapor barriers)
Passive systems will likely require indoor air sampling to monitor (tricky) while active systems can be monitored on their performance (pressure differentials)
Plan should include provisions for actions based on screening (response thresholds)
22a-133k-3(c)(3)(B)

7. No Building
If no building exists, Volatilization Criteria do not apply – Requires:
Environmental Land Use Restriction or
Commissioner approval
Things to mention: No Building ELUR
ELUR can only be added by PROPERTY OWNER
Examples – Naugatuck (RR & state owned land then river) CL&P Easement
22a-133k-3(c)(5)(A)

8. Indoor Air Data Commissioner approval Long-term monitoring
May include environmental measures
Things to mention: Commissioner can add requirements
Really important to discuss with Health Officials/Experts
Again, DPH will require recent info to be used to obtain approval – uphold the protection of human health
Mitigation usually required (some level of control preferred)
22a-133k-3(c)(5)(B)

9. Applying the Volatilization Criteria (applies to both groundwater and soil vapor)
all samples <= to the applicable criteria
95% UCL no longer an option:
Not protective – did not evaluate building structure and air handling practices
No institutional controls were required to ensure conditions wouldn’t change
Things to mention: Easiest if all below.
95% UCL removed – NOT PROTECTIVE
Time Issue (snapshot)
Does not account for interior building structure/air handling (may be acceptable, but unknown)
No Institutional Controls (like elsewhere in RSRs)
22a-133k-3(f)(3)

10. Volatilization Criteria
Q & A