NEW JERSEY VAPOR INTRUSION GUIDANCE Kenneth J. Kloo, Brownfield Administrator ASTSWMO 2008 Mid-Year Meeting Mobile, Alabama April 23 & 24, 2008
NJDEP Vapor Intrusion Guidance VAPOR INTRUSION GUIDANCE NEW JERSEY DEPARTMENT OF ENVIRONMENTAL PROTECTION October 2005
Vapor Intrusion Commercial/Industrial Worker Working over Plume Resident Living over Plume Basement or Crawl Space Without Basement Indoor Air Vadose Zone Soil Gas Soil / GW Contamination Migration of plume vapors to indoor air
Stages of VI Pathway Assessment Preliminary Assessment & Site Investigation Stage 1 Assess potential for Vapor Intrusion Stage 2 Stage 3 Remedial Investigation Stage 4 Stage 5 Rapid Action Determination Evaluate Existing Data Against Generic Screening Levels Develop & Implement VI Investigation Workplan: 4A. Delineate GW contamination 4B. Investigate soil gas 4C. Conduct sub-slab slab and indoor air sampling Evaluate RI Data Using Generic Screening Levels
Stages of VI Pathway Assessment Remedial Investigation (continued) Stage 6 Prepare and Implement Site-Specific Investigative Approach Stage 7 Evaluate Data using Generic Screening or Site-Specific Screening Levels Remediation & Monitoring Stage 8 Stage 9 Stage 10 Stage 11 Determine Appropriate Remedial Action Implement Remedial Action, including Institutional and Engineering Controls Establish a Long-Term Monitoring Program Assess Ability to Terminate Remedial Action
Vapor Intrusion Screening Levels Ground Water Screening Level - calculated using the Johnson & Ettinger (J&E) Model with NJ specific parameters GWSL for Alternate Soil Textures - developed based on lab soil grain size analysis of site soils Indoor Air Screening Level - both residential and non-residential values are updated every six months Soil Gas Screening Level - Calculated using the health based Indoor Air Screening values and an attenuation factor of 0.02 02
Other Screening Levels NJDEP has included additional screening levels: Rapid Action Levels (RAL): trigger levels for the initiation of prompt action 100X cancer health h based residential i IASL 2X noncancer health based residential IASL Health Department Notification Levels (HDNL): trigger levels for the notification of local health department and/or NJ Department of Health & Senior Services (NJDHSS) certain authorities reside with the Health Department
Petroleum Hydrocarbons & Biodegradation The Department recognizes biodegradation occurs GWSLs include a multiplier (10X) for benzene, ethylbenzene, toluene and total xylenes to address biodegradation Multiplier assumes a minimum of 4% oxygen in soil column below structure 30-foot distance criterion for all petroleum-related compounds (but not free product)
Background Indoor Air Contamination SOURCES Consumer Activities Household Products Building Materials & Furnishings Ambient (outside) Air Laboratory Contaminants ACTION Multiple Lines of Evidence Approach
Multiple Lines of Evidence Soil vapor spatial concentrations Groundwater spatial ldata Background (internal and external) Sources Building Construction and Current Condition Sub-slab b Soil Gas Data Indoor Air Data Constituent Ratios
Investigative Tools Groundwater Sampling Soil Gas Sampling Indoor Air Sampling Modeling Sub-Slab Soil Gas Sampling Crawl Space Air Sampling Exterior verses Interior Sampling Passive verses Active Sampling Supplemental Tools / Data
Decision Flow Chart for Vapor Intrusion Pathway Remediation Decision Matrix - Stage 8 Indoor Air Concentrations (for COCs) < IASL >IASL Sub-Slab Soil Gas Concentra ations (for COCs) <SGSL >SGSL to 10X SGSL >10X SGSL No Action No Action or Monitor Monitor or Mitigate No Action * (if no other subsurface source) Investigate further or Mitigate Mitigate Notes: * Investigator should consider the potential for vadose zone (soil) contamination and/or preferential pathways as part of the assessment of vapor intrusion before concluding "no further action" Red Decision Points - investigators should use professional judgement when determining which action is appropriate. Factors to consider include the relative exceedance of the screening level, the ratio of the sub-slab slab soil gas and indoor air results, building construction, and possible affects of background sources of contamination and sampling errors. (Refer to Chapter 7, Evaluation of Analytical Results, for more guidance and information.) Page 4 of 4
Remedial Action Vapor intrusion i remediation - most common are depressurization or SVE systems Reducing vapor intrusion exposure - non-permanent, engineering controls Future use must be considered when vapor intrusion present - institutional controls may be required NJ Certified Radon Mitigation Business - alternately, utilize a licensed Professional Engineer
Mitigation of the VI Pathway Passive barriers Sub-slab depressurization Sub-membrane depressurization Passive venting Sub-slab pressurization Indoor air treatment Building pressurization
RA Sampling Requirements Confirmation IA Sampling - required 2-4 weeks after system is installed - subsequent sampling if initial round not during winter/early spring - any system modifications will require additional sampling Long-Term Monitoring - IA sampling may not be required for subsurface depressurization systems System Termination Sampling - indoor air and sub-slab soil gas sampling required
Institutional Controls Remedial actions (or IRMs) implemented: official i notification of property owner/occupants institutional controls not required Undeveloped Parcels: official notification of property owner/occupants institutional controls required at closure Use of nonresidential screening levels or site specific building parameters: agreement with property owner and institutional control as part of RAW submission
Community Outreach With VI, Communicating with public officials, health officers, residents, property owners, and media is critical Community Outreach Approach: Scheduling indoor sampling events Reporting sample results in a timely manner Organizing public meetings (various formats) Responding to public questions and concerns
New Low Level Air Analysis Method Certification process underway for Method NJDEP- LLTO-15-3/2007 Implications: lower reporting limits (0.2 ppbv) achievable for a majority of the chemicals adding approximately three chemical parameters anticipated implementation in Summer 2008 With the new method in place, USEPA Method TO-15 will no longer be acceptable for soil gas, indoor or ambient air samples.
UPDATE: Reporting Units for Air / Soil ilgas Results Starting with the issuance of the new updated tables this summer 2008, the Indoor Air and Soil Gas Screening Levels will only be provided in units of µg/m 3. IASL and SGSL will no longer be given in units of ppbv. As of this summer 2008, all soil gas, indoor and ambient air results must be reported in units of µg/m 3 only for all documents submitted to the NJDEP.
CLARIFICATION: General VI Investigative Procedures VIG Recommended Approach: Ground Water Soil Gas Indoor Air Consultant s WRONG Interpretation: Ground Near Sub-Slab Indoor Water Slab Soil Soil Gas Air Gas
CLARIFICATION: Indoor Air Sampling in Known Worst Case Environments The NJDEP generally does NOT recommend collecting indoor air samples in structures where it is reasonable to assume extremely high indoor air contaminant levels exist Alternative sample media (GW, Sub-slab soil gas) can be collected to assess the VI pathway Examples: dry cleaners, gas station convenience stores
CLARIFICATIONS: Use of Distance Criterion for VI Assessments Distance Criteria Petroleum hydrocarbons Free product and all other dissolved compounds 30 feet 100 feet The distance criteria are applied to the edge of the groundwater plume in determining which structures should be investigated. It is NOT acceptable to collect a GW sample at a distance less than the prescribed criteria and assume that no contamination at that distance implies the VI pathway is incomplete.
NJDEP Current Policy NJDEP Vapor Intrusion Web Site www.nj.gov/dep/srp/guidance/vaporintrusion/ Currently contains links to: NJDEP Vapor Intrusion Guidance (October 2005) Rutgers University VI Seminar slides Updated Screening Level Tables NJDEP Certified Laboratories - EPA Method TO-15 & TO-17 NJDEP Modified J&E Model Spreadsheet NJDEP Regulatory Reporting Format and Electronic Deliverables Requirements Method TO-15 Units Conversion Table (Excel format or zip file)
Questions john.boyer@dep.state.nj.us t j (609) 984-9751