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USEPA Region II Data Summary and

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USEPA Region II Data Summary and Powered By Docstoc
					USEPA Region 2
Vapor Intrusion Study
Cayuga Groundwater Contamination Site
March 4, 2009
Site Background

   2001 to Present – EPA Field Study
     – Installed 23 Multi-level monitoring wells
     – Seven Rounds of groundwater sampling (>500
       groundwater samples)
     – Quarterly water level measurement and
       geophysics support from USGS
     – Surface water/sediment samples (Owasco
       Outlet, Crane Brook, Union Springs)
Site Background (cont’d)

    Cayuga County DOH –1999-2008 - Multiple
     rounds of residential well sampling (>600
     samples)
    Remedial report and risk evaluations in
     progress
Monitoring Wells
Site Overview
Ongoing Field Study Efforts

    Additional field work under NYSDEC/EPA:
     – Additional monitoring wells
     – Additional groundwater sampling
     – Geophysical survey
     – Hydraulic testing
Vapor Intrusion Study

   EPA field study indicates that chlorinated
    volatile organic compounds (CVOCs) are
    present in groundwater
   CVOC-contaminated groundwater extends
    from West Genesee St. to Union Springs
   CVOCs in groundwater can form vapors that
    migrate in the subsurface
   Potential exists for vapors to enter buildings
   Vapor sampling is being conducted to
    determine if vapors are present in buildings
Vapor Sampling Locations

   Selection of locations based on existing data:
     – Location of CVOCs in groundwater
     – Location of CVOCs in surface water
     – Residential well data
     – Human health risk evaluation
     – Geologic/Hydrogeologic factors
           Depth to contaminated groundwater (<100 feet)
           Degree of bedrock fracturing
           Presence of clean groundwater above
            contaminated zones
Vapor Sampling Locations (cont’d)

   Three areas identified that meet initial
    criteria:
     – South of West Genesee Street
     – Pinckney Road/Overbrook Drive Area
     – Union Springs
South of West Genesee Street


   Insert Figure 1
Pinckney/Overbrook Area (east)


   Insert Figure 2
Pinckney Road (West)
Union Springs Area (south)


    Insert Figure 3
Union Springs Area (north)
Residential Vapor Intrusion Sampling
Procedures
    Presented by:
    Gary Newhart – EPA
     Ventilation                        Ventilation



Ambient air                                  Ambient air
                     Interior space


                     Subslab soil gas
                      intruding into
                      interior space

                     Vadose Zone



              Groundwater Contamination

              Vapor Pathway into Buildings
Key Questions for Vapor Intrusion
Impacts
 1. Does groundwater or soil contamination exist?
    - Yes, in this case, so we move to the next step

 2. Does subsurface gas contamination exist above
    guidelines?
    - Answered through collection of subslab soil gas

 3. If subsurface gas does exist above guidelines, is it
    entering the interior space?
    - Answered through collection of indoor air samples

 4. If gas contamination exists in the residence, are the
    concentrations elevated and related to contamination
    - Answered by comparing results to health-based
    guidelines and conducting lifestyle and ambient
    investigation
Monitoring and Sampling Strategy

  1. Initial Sampling
        - Subslab Location + Ambient (outdoor)

  2. Subsequent SUMMA Canister Sampling
        - Subslab Location
        - Basement Location
        - First Floor Location
Indoor Air and Sub-Slab Soil Gas
Activities
Drilling
Placement and Cementing of the Probe
Connection of the 3-Way Valve
Vapor Sampling Apparatus
Vapor Mitigation System
What is a VI Matrix and how is it developed?

      Chemical-specific
      Considers potential health effects from long-
       term exposures for residents including
       children and adults
        – Exposure Frequency of 24 hours/day and 350
          days/year
        – Exposure Duration is 30 years
      Has comparison values for subslab soil gas
       and indoor air
                                  Vapor Intrusion Matrix for a Carcinogenic Chemical


Step 1. Does the subslab concentration exceed x ug/m3?
        No = Vapor intrusion investigation is over for this building
        Yes = Consider indoor air sampling

Step 2. Evaluate subslab and indoor air concentrations.

                                 Indoor Air Concentration (ug/m3)
     Sub-slab Soil
         Gas
     Concentration



                       (1) No Action      (2) Investigate     (3) Investigate


                                           (5) Monitor or     (6) Investigate
                        (4) Monitor            Pursue           or Pursue
                                            Remediation        Remediation

                       (7) Monitor or      (8) Pursue_
                                                               (9) Pursue
                           Pursue         Remediation or
                                                              Remediation
                        Remediation          Monitor
                             Vapor Intrusion Matrix for a Non-Carcinogenic Chemical


Step 1. Does the subslab concentration exceed x ug/m3?
        No = Vapor intrusion investigation is over for this building
        Yes = Consider indoor air sampling

Step 2. Evaluate subslab and indoor air concentrations.

                                  Indoor Air Concentration (ug/m3)
      Sub-slab Soil
          Gas
      Concentration




                            (1) No Action               (2) Investigate




                       (3) Monitor/ Remediate           (4) Remediate
VI Decisions

    VI Profile
      – Subslab
      – Indoor/Basement
      – Indoor/First Floor Living Space
      – Ambient Concentrations
    Confounding Internal Sources
    Confounding External Sources
Key Points in VI Decisions

    Decision to remediate is not based on one
     piece of information
    Complexity and uncertainty is associated
     with the fate and transport mechanism of
     vapors
    Multiple lines of evidence are used in the
     decision making
    Rely on “VI Team” to ensure consistency in
     decisions within EPA Region 2
Contact Information
   USEPA Remedial Project Manager - Isabel
    Rodrigues – (212) 637-4248
   USEPA Community Involvement Coordinator–
    Mike Basile - (716) 551-4410
   New York State DOH – Krista Anders – (518)
    402-7860
   New York State DEC – Kevin Kelley – (315)
    426-7421
   Cayuga County DOH – Eileen O’Conner (315)
    253-1405

				
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