Project would review forensic/fingerprinting approaches being employed in the industry for PFAS source differentiation, assess the validity and usefulness of the approaches used, and summarize those approaches in a guidance document. Additionally, the project would create a tool for airports to perform some level of fingerprinting assessment of PFAS impacts to soil or groundwater to discrimnate between multiple sources likely in he airport setting.
Airports across the United States face increasing regulatory and technical challenges for addressing Per- and Poly-Fluoroalkyl Substance (PFAS) releases to groundwater or surface water from the use of Aqueous Film Forming Foams (AFFF) in Aircraft Rescue and Fire Fighting (ARFF) activities. These activities, including storage, training, equipment maintenance and testing, and emergency response actions, may lead to release of AFFF and subsequent liability for investigation and management costs, as well as possible costs for damages caused by the release. In many cases, airports have tenants on leased airport property with AFFF storage, usage, and training with associated incidental release, such as hangar suppression systems testing, maintenance activities, or fire protection for bulk fuel storage operations. Additionally, airports located in heavy industrial areas may have neighbors with AFFF or other PFAS usage and potential release to nearby groundwater or surface water. Construction activities often lead to discovery of PFAS-impacted soils, with no concept of where the PFAS might have come from. It should be noted that other sources for PFAS at airports exist, such as fluorinated hydraulic oils, wastewater from rental vehicle washing/servicing facilities, and other PFAS-containing materials may have been used at airports, in leased hangars, or by adjoining support businesses. PFAS are a complex group of contaminants and often times, key compounds present, ratios between certain compounds, or overall groups of compounds can be indicative of specific uses. For instance, older AFFF using electrofluorination manufacturing included PFOS and related compounds, but newer fluorotelomer foams included PFOA and PFOA-precursors. Another example is in chrome plating operations, which used PFOS-laden foam but did not commonly use products with PFOA. Conversely, grease-resistant coatings, such as those used for fabrics and carpets primarily used products containing PFOA and rarely included PFOS. Distinguishing between PFAS source areas is an important aspect of any site characterization program and is useful for managing the cost and liability of contaminant management and remediation. PFAS forensic/fingerprinting tools and approaches have been developed recently by a number of organizations to attempt to distinguish between sources. Research is needed to advance the understanding of this approach to source differentiation so it can be applied to airports and related sites with greater confidence.
The objectives of this research are to (1) compile information on existing forensic approaches, (2) evaluate strengths and weaknesses of those approaches, and (3) develop a standardized approach for forensic evaluation of PFAS data towards differentiating among multiple potential sources.
Task 1. Conduct a literature review related to forensic assessment in general (e.g., for other groups of contaminants), as well as for PFAS specifically. Given that the PFAS issue is more recent, there may be a paucity of peer-reviewed publications on this topic. Conference presentations, opinion pieces, or other sources that are not validated broadly may still have value and should be evaluated and considered in the literature review. The review should include the basis for the evaluation, methodologies applied, and results. This task would include preparation of a summary table of the reviewed approaches, that includes a brief description and reference information for each. Compare the methodologies reviewed, looking for robustness, scientific merit, effectiveness of findings, applicability beyond the presented examples, and level of effort and expertise required to implement that approach Additionally, render opinions on possible combinations of different approaches to increase applicability or confidence. Organize forensics methodologies by application, state of development, type of differentiators, cost (if known) and availability. Develop a conceptual model of PFAS releases at or near airports. Develop objectives and endpoints for an airport forensic evaluation.
Task 2. Prepare a Research Plan to develop a standardized approach or tool that brings together the most effective scientific approaches of the ones reviewed and allows forensic evaluation to be available to the broad airport community. This plan should include a summary of the review of existing approaches, the scientific/technical merit of preparing a standardized approach, the steps necessary to develop the approach/tool, expectations on applicability of the approach/tool, estimation of the level of effort to create the approach/tool, estimation of the level of knowledge needed to utilize the approach/tool and plans for Tech Transfer of the approach/tool to the industry. The approach could involve a defined procedure (e.g., cookbook), a spreadsheet form/tool, a web-based analysis and visualization tool, or other techniques at the discretion of the contractor.
Note: The ACRP project panel will review and comment on the Task 2 research plan within 2 weeks of receipt. A conference call will be conducted with the ACRP project panel and the contractor to discuss the Task 2 research plan. ACRP approval is required before proceeding with subsequent tasks.
Task 3. Execute the approved Task 2 research plan (development of a standardized forensic approach/tool) and summarize the results.
Task 4. Prepare a detailed outline for a guidebook to help airports learn and utilize the forensics tool.
Note: Proposers should include an initial guidebook outline in their proposal.
Task 5. Prepare an interim report summarizing the results of Tasks 1 through 4.
Note: Allow 1 month for panel review of the interim report. Within 1 month after this review period, the contractor shall meet with the panel to discuss research to date and address panel comments. ACRP approval is required before proceeding with subsequent tasks.
Task 6. Prepare a guidebook to help airports learn and utilize the forensics approach/tool. The guidebook should include, at a minimum, a summary description; considerations on applicability of usage; data needs; addressing uncertainty in results; order-of-magnitude cost/LOE estimates for utilization at a typical small, medium and large airport; and critical parameters (e.g., data gaps, training, capability) affecting performance/usage.
Task 7. Prepare a final report that documents the background material used in the development of the guidebook.
The level of effort by task is as follows:
Task 1 - Literature Review - $90K
Task 2 - Research Plan - $30K
Task 3 - Develop Standardized Approach/Tool - $220K
Task 4 - Outline for Guidebook - $20K
Task 5 - Interim Report - $40K
Task 6 - Prepare Guidebook - $50K
Task 7 - Final Report - $40K
Total cost approximately: $490K
Minimal additional costs are expected (e.g., no travel, no purchased equipment).
Proposals should consider related ACRP studies, including ACRP Report 173: Use and Potential Impacts of AFFF Containing PFASs at Airports, as well as other resources for PFAS information, such as documents from the Interstate Technology & Regulatory Council (ITRC) the National Groundwater Association; the United States Environmental Protection Agency, and available state guidance (for example: Michigan, California, Minnesota and New York guidance). US DOD is presently funding several research projects related to PFAS forensics under this solicitation: ERSON-20-C5: Forensic Methods for Source Tracking and Allocation of Per- and Polyfluoroalkyl Substances, these studies' approach and results, if available will be incorporated into the airport-focused forensics evaluation and approach/tool.