Today, January 17, 2013: NJDEP published major changes to guidance and standards pertaining to Vapor Intrusion. Vapor Intrusion is defined as the migration of volatile chemicals from the subsurface into overlying buildings through subsurface soils or preferential pathways (such as underground utilities). This pathway has been the driver for many off-site investigations, public notifications and costly indoor air testing since the NJDEP’s initial guidance came out in 2007.
Just released on the NJDEP’s Vapor Intrusion web page is the revised Vapor Intrusion Technical Guidance document and updates to the 2007 Vapor Intrusion Screening Levels (VISL). Finally, the web page also features Johnson & Ettinger (J&E) Model spreadsheets that were updated to reflect toxicity changes in the new VISL.
- The 2013 Vapor Intrusion Screening Levels can be found here: http://www.nj.gov/dep/srp/guidance/vaporintrusion/vig_tables.pdf
- The 2013 Vapor Intrusion Technical Guidance can be found here: http://www.nj.gov/dep/srp/guidance/vaporintrusion/vig_main.pdf
Here are just some of the changes:
Naphthalene and 2-methylnaphthalene have been added to the VISL tables. At this time, the laboratory capacity to analyze naphthalene and 2-methylnaphthalene using the preferred USEPA Method TO-17 is limited (only one certified laboratory). Therefore, the Department will not require the collection and analysis of naphthalene and 2-methylnaphthalene until July 16, 2013.
A factor of 10 has been incorporated into the calculation of the health-based ground water screening values for additional petroleum related contaminants (not reflected in the March 2007 tables) to account for degradation of the contaminants in the unsaturated zone. The additional petroleum related contaminants include: 1, 3-butadiene; cyclohexane; n-hexane; 2-methylnaphthalene; naphthalene; and styrene.
Five contaminants have been eliminated from the VISL tables due to the absence of inhalation toxicity information. These chemicals include: 1, 3-dichlorobenzene; 1, 2- dichloroethene (cis); 1, 2- dichloroethene (total); 2-chlorotoluene; and tertiary butyl alcohol (TBA).
Changes to many previously regulated compounds, including increases in groundwater screening levels for tetrachloroethylene (aka PCE) (up to 31 ug/l from a prior standard of 1 ug/l) and trichloroethylene (TCE) (up to 2 ug/l from a prior standard of 1 ug/l) for example, were also made.
Consult your LSRP regarding how these changes affect your project, or feel free to contact REPSG directly at email@example.com.