Early History of the Vapor Intrusion Pathway 14 th Steven Amter,, MS Disposal Safety Incorporated Washington, DC Vapor Intrusion Attenuation Workshop th Annual West Coast Conference on Soils, sediments, and Water March, 2004
Presentation outline VIP defined (for the purposes of this talk). Precursors. Development of modern emphasis on chronic exposure. Selected mileposts in regulatory/guidance. Selected mileposts in science and modeling. Consultant involvement. What good is history?
VIP defined for this presentation Migration of vapors from the soil zone into structures as defined by USEPA (2002). Includes all gaseous contaminants, but my emphasis is on halogenated aliphatic hydrocarbons and petroleum constituents. Includes all sources, but my emphasis on ground water-to to-soil gas pathway. Focus on VIP w/r to risks from chronic exposure.
Precursors to exposure pathway Petroleum exploration by soil gas analysis for hydrocarbons (1930s onward). Use of volatile chemicals as root zone fumigants (1950s onwards). Landfill gas surveys/radon surveys (1960s onwards).
Precursors (continued) VOC plume mapping by soil gas surveys (developed late 1970s; standard technique by the late 1980s.) Vapor intrusion risk from acute exposure or fire/explosion, mostly from petroleum (1960s onward). Transitional: by early 1980s, chronic risks sometimes considered in tandem where acute risks identified.
Chronic exposure and risks via VIP Late 1970s/early 1980s saw a rise in concern over: VOCs as inhalation carcinogens (1970s). Residential indoor air quality (early 1980s); a hot topic. Radon intrusion (early 1980s).
egulatory/guidance mileposts 1 1980: RCRA 261.31 F001 listing for spent degreasing solvents: TCE/PCE mobility in ground water; volatility; carcinogicity; ; vapors intrusion into basements. 1985: Love Canal Enforcement: Dr. Brian Murphy models VIP into basements as part of a risk assessment. 1986 RCRA OSWER Corrective Action Directive required investigation to characterize subsurface gasses from buried waste and hazardous constituents in the ground water.
Regulatory/Guidance mileposts 2 1989 RFI Guidance for Conducting RI/FS briefly mentions inter-media transfer from ground water to soil gas to air. 1992: Air/Superfund guidance: Assessing Potential Indoor Air Impacts for Superfund Sites. Includes several case studies. 1993: Air/Superfund guidance: Options for Developing and Evaluating Mitigation Strategies for Indoor Air Impacts at Superfund Sites. Includes examples.
Regulatory/Guidance mileposts 3 Mid-1990s onward: Some states require evaluation of the VIP (MA, MI, CT, RI). 1994/1995: ASTM develops RBCA standard for petroleum releases that includes VIP. 1996 NPL guidance: Soil Screening Guidance User s Guide. (Conceptual site model same as 1988 RI/FS guidance). 2001/2002 USEPA Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils
Selected mileposts in modeling Dr. Brian Murphy VI model (1985). Conceptual models presented in 1986 at Society for Risk Analysis Annual Conference. Johnson and Ettinger (1991): Heuristic Model for Predicting the Intrusion Rate of Contaminant Vapors into Buildings. Little, Daisey,, and Nazaroff (1992): Transport of Subsurface Contaminants into Buildings: An Exposure Pathway for Volatile Organics.
Selected mileposts in science and modeling (continued) 1992: Air/Superfund guidance: Assessing Potential Indoor Air Impacts for Superfund Sites. Lays out a screening and evaluation procedure and includes examples with risk calculations.
ield investigations/consultant work* 1989/1990: Kodak consultants Radian and Tracer Research test indoor air in homes near Kodak Park (NY) to investigate VIP for chlorinated solvents. 1989: Four consulting companies (Hank Cole, Kirk Brown and Associates, Hampshire Research Institute, and Disposal Safety Inc.) raise VIP for chlorinated solvents in report submitted to USEPA at a Superfund site in OH. 1991: Evaluation of VIP for chlorinated solvents (Sunstrand site in CO) and petroleum (Amoco site in IN).
Field investigations/consultant work* (continued) VIP (chlorinated solvents) in ROD at Superfund sites: Chemical Sales Co. (1991, CO); Advanced Micro Devices and TRW Microwave sites(1992, CA); Hill Air Force Base (1994, UT). 1996 onward: Investigation and mitigation required by Colorado regulators at several prominent Denver area sites: CDOT; Redfield rifle scope; Lowry Air Force Base.
Why history? Interesting in its own sake. A complete (as possible) history is the starting point for discussions of past decisions and actions. Helps us recognize analogous circumstances in the present.
Why History? (Cont.) Useful to social history, legal proceedings. Publicizing history helps ensure accuracy when our profession talks about history, which we sometimes must. *Add your experiences to history: cataloging early VIP work.