The objective of this Statement of Need (SON) was to develop passive sampling methods to provide repeatable and environmentally relevant measures of per- and polyfluoroalkyl substances (PFAS). The focus of this work should have been for at least the USEPA 24 PFAS shown in Table 1 and total PFAS in groundwater, surface water, stormwater run-off, and porewater in soils and/or sediments (collectively referred to here as “water”). Specific objectives of this SON included:

• Develop passive sampling media competent to quantitatively “concentrate” the wide range of PFAS (nonionic, anionic, and zwitterionic) of interest from water.
• Establish physical-chemical properties, including sorbent/water partition coefficients, molecular diffusivities of PFAS in water and sorbent media.
• Establish the range of PFAS that can be quantifiably sampled using the sorbent(s) (e.g., long chain vs short chain, precursors versus perfluoaroalkyl acids).
• Characterize the impacts of co-contaminants and various water quality and conditions (e.g., freshwater versus salt water, surface waters with biofouling versus groundwater).
• Develop a fundamental understanding of the natural solid-water sorption coefficients of PFAS as a function of sorbate properties, natural solids, and solution properties (pH, major ions, dissolved organic carbon).
• Develop passive samplers that yield representative spatial and temporal interrogation of site contaminants when deployed.
• Develop passive sampling methods/procedures that are capable of being efficiently deployed and retrieved in widely varying field applications (e.g. groundwater, stormwater, surface waters, porewaters).

Proposers should have considered means of establishing equilibria in sampling media, including suitable performance reference compounds across the wide range of PFAS expected, or methods for determining time weighted averages of PFAS loading into aquatic systems. Proposers should have been aware of the requirements of the Department of Defense Quality Systems Manual for Environmental Laboratories (QSM 5.1) in terms of ultimate targets for quality assurance and quality control. Proposals should have addressed one or more of the objectives listed above.

Funded projects will appear below as project overviews are posted to the website.

Addressing the research needs described above will meet a critical need for better sampling and analysis of PFAS at Department of Defense (DoD) sites. This will in turn lead to improved and more cost effective management of PFAS sites by facilitating more accurate and precise assessments of the extent of PFAS contamination.

PFAS are present in AFFF used by the DoD and other organizations to extinguish hydrocarbon fires. Different AFFF formulations have been used, but all contain a complex mixture of PFAS, including those of greatest regulatory concern - the PFAAs and potential PFAA precursors (Field et al., 2017; ITRC, 2017). EPA has recommended a Health Advisory Level for perfluorooctanoic acid (PFOA) and PFOS, and several states have promulgated standards for PFOA, PFOS, and some of the related PFAAs (ITRC, 2018a).

SERDP has been funding research on AFFF contamination for several years to improve PFAS analysis, to develop tools for assessing the fate of PFAS in the subsurface, and to evaluate the potential for in situ remediation. A recent SERDP & ESTCP-sponsored workshop identified a number of research needs, and proposers should view the Workshop Report to obtain additional detail concerning these discussions. PFOS is of particular concern to DoD, as it is the predominant PFAS in some AFFF formulations, and a significant dead-end metabolite in others, and therefore it is typically the predominant PFAS in AFFF-impacted groundwaters (Anderson et al., 2016). PFOS appears to be particularly resistant to destructive technologies, and like the rest of the PFAAs it is generally considered nonbiodegradable (ITRC, 2018b).

The development of standardized procedures for field sampling of environmental waters was identified as a critical priority research need in the SERDP & ESTCP Workshop Report. Currently, no single document or source exists for these procedures. The EPA’s Office of Research and Development is currently leading an effort to create and validate sampling procedures for environmental water and sediment/soil media. However, the timeframe for full validation of sampling procedures is unknown and their applicability to DoD projects is yet to be determined.

The cost and time to meet the requirements of this SON are at the discretion of the proposer. Two options are available:

Standard Proposals: These proposals describe a complete research effort. The proposer should incorporate the appropriate time, schedule, and cost requirements to accomplish the scope of work proposed. SERDP projects normally run from two to five years in length and vary considerably in cost consistent with the scope of the effort.

Limited Scope Proposals: Proposers with innovative approaches to the SON that entail high technical risk or have minimal supporting data may submit a Limited Scope Proposal for funding up to $200,000 and approximately one year in duration. Such proposals may be eligible for followon funding if they result in a successful initial project. The objective of these proposals should be to acquire the data necessary to demonstrate proof-of-concept or reduction of risk that will lead to development of a future Standard Proposal. Proposers should submit Limited Scope Proposals in accordance with the SERDP Core Solicitation instructions and deadlines.