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Petroleum Vapor Intrusion: New Jersey DEP’s Approach John E. Boyer NJ Dept. of Environmental Protection [email protected] October 2011 Vapor Intrusion (VI) Pathway Commercial/Industrial Worker Working over Plume Resident Living over Plume Basement or Without Basement Crawl Space Indoor Air Vadose Zone Soil Gas Soil / GW Contamination Migration of subsurface vapors to indoor air Courtesy: ITRC VI Investigation Triggers Conditions triggering a VI investigation [7:26E-1.18(a)]: Petroleum hydrocarbons above GWSL within 30 feet of a building Non-petroleum VOCs above GWSL within 100 feet of a building Free product within 100 feet of a building Any of the following conditions: – Soil gas or indoor air contamination above VI Screening Levels (SLs) – A landfill located on or adjacent to the site – A wet basement/sump with free product and/or detectable GW contaminants – Potentially explosive methanogenic conditions – Any other information that indicates human health impact VI Screening Levels NJDEP’s Vapor Intrusion Screening Levels (VISLs) are in the process of being updated. VISLs are located in the Department’s VI website at http://www.nj.gov/dep/srp/guidance/vaporintrusion/ Soil gas attenuation factor of 0.02 will be maintained for the immediate future Petroleum Hydrocarbons (PHC) ASTM Petroleum Hydrocarbon Volatile Chemicals of Concern is defined as “petroleum hydrocarbons such as benzene, xylenes, toluene and ethylbenzene (or a mixture of such chemicals) that are a subset of volatile chemicals of concern and that are distinguished because they are known to readily biodegrade to carbon dioxide in the presence of oxygen by ubiquitous soil microbes.” NJDEP PHC Approach (2005 – 2011) The Department recognizes biodegradation occurs VI Groundwater screening levels incorporate 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) Proposed Critical Distance Criteria Distance from the edge of the GW plume to a structure or undeveloped land Dissolved Volatile Contaminant Dissolved PHC Contaminant Free Product Free Product – PHC 100 feet 30 feet 100 feet 30 feet?? Proposed Gasoline Exclusion Criteria VI Investigation is not required when: ≥10 ft between water table and foundation and benzene in GW is ≤1,000 μg/L No VI Investigation 3• 10–feet more PCE 325 or μg/m Benzene – ND to 1,000 μg/L Proposed Gasoline Exclusion Criteria VI Investigation is not required when: ≥5 ft between seasonal high water table and benzene in shallow GW is ≤100 μg/L No VI Investigation 3• more PCE5 –feet 325or μg/m Benzene – ND to 100 μg/L Proposed Gasoline Exclusion Criteria VI Investigation is not required when: ≥5 ft between seasonal high water table and foundation, oxygen levels measured at ≥2% (v/v), and benzene in shallow GW is ≤1,000 μg/L. No VI Investigation 5 feet or –more & O23 • ≥ 2% PCE 325 μg/m Benzene – ND to 1,000 μg/L Gasoline Exclusion Conditions Conditioned upon: A relatively small detached building with the area not extensively paved; and Clean soil exists between the water table and the foundation; and NAPL is not present within 30 ft (vertically or horizontally) No. 2 Fuel and Heavier PHCs VI investigation not required based exclusively on a discharge of No. 2 fuel oil or diesel (free product) If free product (soil and/or water table)removed within 6 months, GW investigation to assess VI can be delayed until remedial action completed (UHOT provision) Naphthalene and 2-methyl naphthalene (in addition to benzene) are the exclusive target compounds for VI investigation trigger Current modifications limited to diesel and No. 2 fuel oil Future changes will be expanded to all heavier fuels VI Investigative Issues Related to PHCs Highlights of Investigative Strategies Avoid collection indoor air samples in buildings where the contaminants of concern are utilized (i.e., dry cleaners) Consider methane and its implication to a VI investigation ITRC – Shaping the Future Host organization Network • State regulators All 50 states and DC • Federal partners • ITRC Industry Affiliates Program • Academia • Community stakeholders Wide variety of topics • Technologies • Approaches • Contaminants • Sites Products • Documents Technical and regulatory guidance documents Technology overviews Case studies • Training Internet-based Classroom Interstate Technology & Regulatory Council Petroleum Vapor Intrusion Team Approved by the ITRC Board for 2012 Membership will open in mid February 2012 Open to all interested persons (regulators, industry, consultants, academia, community stakeholders) First meeting will be in April 2012 at the ITRC’s Spring meeting in Des Moines, IA Questions?