Lead Investigator: David Kosson (Vanderbilt University)

Additional Investigators: Jenn Guelfo (Texas Tech), Kevin G. Brown (Vanderbilt University), Joanna Burger and Michael Gochfeld (Rutgers University), Haruko Wainwright (MIT), and additional academic experts may be added as consultants.

Project Objectives:

The objectives of this project are to:

1. Recommend sampling, analysis, and data evaluation approaches for determining background concentrations of per- and poly-fluoroalkyl substances (PFAS) in soils; water (groundwater, ponds, precipitation); and biota at EM sites; and,
2. Develop a prototype background determination plan for WIPP.

Significance/Impact:
The identification and quantification of background concentration levels are critical when evaluating human health and ecological risks posed by contaminated sites, including those at DOE sites (Vyas, et al 2006). Background levels are defined by the U.S. Environmental Protection Agency (EPA) as being of two types: naturally occurring levels and anthropogenic levels because of diffuse anthropogenic, non-site sources (USEPA 2003). Background levels are used in a regulatory context to distinguish contamination from identifiable site-specific sources and activities from naturally occurring levels or contamination from non-site-related sources and activities. PFAS contamination may arise from distinct releases or diffuse sources; however, PFAS arises only from anthropogenic sources. Background levels can also be used to evaluate whether the threat to human health or the environment is posed by known or existing sources, to set remediation goals, and to communicate cumulative risks associated with contaminated sites (USEPA 2001).

High-quality background data are critical to a successful statistical groundwater monitoring program, especially for detection monitoring (USEPA 2009). The statistical tests used to define background levels are predicated on having appropriate and representative background measurements, where a statistical sample is representative if the distribution of sample measurements follows the distribution of the population from which the sample is drawn, but background data must also reflect the historical conditions unaffected by the activities that the background will be compared.

Public Benefit:
There is a large number (perhaps exceeding 20,000 compounds), and varying properties of per- and poly-fluoroalkyl substances (PFAS), and their widespread use may make identification of sources and background concentrations often difficult, in general. In general, the determination of background concentrations can be a thorny problem because of the often-sparse nature of the environmental data involved; this applies to many areas including those outside of DOE; improvements to the process would have widespread impact. Because PFAS found present in environmental media at a site may not be the result of or influenced by site activities or releases, it is critical to be able to discern the actual source(s) of the PFAS to which the determination of background concentration is essential.

References: (* indicates CRESP publication)

U.S. Environmental Protection Agency, Office of Emergency and Remedial Response. (1989). Risk Assessment Guidance for Superfund, Volume 1: Human Health Evaluation Manual (Part A) (EPA/540/1–89/002). Washington, DC.

U.S. Environmental Protection Agency, Office of Emergency and Remedial Response. (2001). Guidance for Characterizing Background Chemicals in Soil at Superfund Sites (EPA 540-R-01–003). Washington, DC.

U.S. Environmental Protection Agency. (2009). Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities Unified Guidance (EPA 530/R-09-007). Washington, DC.

* Vyas, V. M., Roy, A., Georgopoulos, P. G., Strawderman, W., & Kosson, D. S. (2006). Development and Application of a Methodology for Determining Background Groundwater Quality at the Savannah River Site. Journal of the Air & Waste Management Association, 56(2), 159–168. https://doi.org/10.1080/10473289.2006.10464452