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88 Based on the findings from ACRP Project 02-60, the following data gaps regarding the use and potential impacts of AFFF containing PFASs at airports were identified and warrant further research. The data gaps have been listed in order (relative to representing an environmental concern) of being preventative, mitigative, and restorative. Alternatives to AFFF Containing PFASs. There is a perceived need for the development of firefighting foam alternatives to AFFF that do not contain PFASs and can be used in the United States and Canada. The superior fire knockdown capabilities of AFFF are important from efficacy and safety perspectives. However, jurisdictions outside the United States and Canada have switched to non-fluorinated foams and/or foams that do not contain PFASs, and, while they do not meet the regulatory requirements of the FAA and Transport Canada, they are acceptable pursuant to the International Civil Aviation Organizationâs firefighting foam criteria. More- over, even though the current regulations do not specify AFFF, the requirements for the foam (through MIL-SPEC or through Transport Canada) limit the types of products that can be used as true alternatives. Initial research into AFFF alternatives was conducted under ACRP 02-60 (and included as Appendix B); however, the scope of the project required identifying suitable AFFF alternatives available to airports within the United States and Canada. Further research is warranted on whether AFFF alternatives available outside North America can or should be acceptable (e.g., through specification requirement changes, product approvals, or advances in foam development). Disposal Methods. The survey of airports conducted for this research identified a knowl- edge gap in how airports dispose of AFFF concentrate. Specifically, with changing regulations and increased awareness of the potential environmental impacts of AFFF containing PFASs (and, in particular, PFOS-containing AFFF), many airports interested in proactively making the switch to more environmentally friendly AFFF alternatives are wondering how to dispose of existing stock of PFOS- or PFOA-containing AFFF concentrate. Identified disposal options (e.g., return to manufacturer and incineration) may not be available or may be too costly, leaving airports to stockpile AFFF waste until more cost-effective options become available. Further research is recommended to identify viable, cost-effective disposal options. Replacing AFFF in Existing Systems. Further research should evaluate whether residual PFASs bind to existing systems (e.g., hoses, storage containers, etc.). In the event that it is found that PFASs do bind to these systems, methods for eliminating residual PFASs should also be studied. Costs associated with these methods, which could include flushing the systems or full replacement, could be an element of this research. Environmental Standards for AFFF. There are currently no standards for evaluating the environmental acceptability of a firefighting foam product. Further research into providing a standard that takes a more holistic approach to the potential long-term and short-term effects C h a p t e r 7 Recommendations for Future Research
recommendations for Future research 89 of these foams could be performed by looking at bioaccumulation, persistence, toxicity, and BOD/COD. A recognizable standard would assist airport representatives to more easily factor environmental considerations in the procurement, storage, application, and disposal of fire- fighting foam. Evaluation of Existing Separation/Treatment Facilities for Processing Wastewater Impacted by PFASs. Responses to the survey indicated that some airports used existing glycol-water and/or fuel-water separation systems for pretreatment of wastewater impacted by PFASs prior to sending discharged foam solutions to a wastewater treatment facility. The efficacy of these systems in removing AFFF has not been studied, and it is not known whether amendments to these systems could foster adequate AFFF removal. Further research is also recommended to evaluate volume criteria for disposal in local water treatment facilities. Most local municipal or airport-specific water treatment plants may not be effective in processing large volumes of runoff impacted by PFASs following training, testing, or emergency response. The research will help airports assess the effectiveness and viability of disposing of waste impacted by PFASs (i.e., discharged AFFF/water mixtures) using existing facilities. Understanding How Firefighting Can Be Optimized. Further research is recommended to identify how foam concentrate characteristics, equipment, and application techniques can be optimized to provide overall suppression performance equivalent to AFFF without the use of fluorochemicals. The literature suggests that application techniques can help compensate for limitations associated with specific foam concentrate characteristics. For example, in using non- film-forming foams, the ability of the foam to extinguish the fire (i.e., in the absence of the film formation typically provided by fluorocarbon surfactants) can be improved by adjusting other (e.g., mechanical) properties of the foam such as reducing the rate of water drainage in order to lower yield stress on the foam. Broadly Applicable Analytical Methods. Current commercially available analytical methods do not quantify all PFASs, including precursors that may degrade and/or transform into more persistent daughter compounds. As a result, available standardized laboratory methodologies may be inadequate to fully characterize the nature and extent of the impacts of PFASs and the associated environmental risk and liability to an airport. Further research is recommended to assess the applicability of precursor analysis and total organic fluorine analysis and how the analytical results (as a better representation of concentrations of PFASs in environmental media) may influ- ence the assessment of human health and ecological risk and the corresponding development of regulatory criteria for PFASs. Environmental and Human Health Risks Associated with Short-Chain PFASs in AFFF. In response to evidence of potential environmental concern associated with some PFASs and subsequent changes in regulation, manufacturers have shifted to AFFF formulations that are created through telomerization using short-chain PFASs. Although the short-chain compounds of PFASs are thought to be less persistent and less bioaccumulative, limited research has evaluated the behavior of these compounds in the environment and/or the potential risks they pose to human health or the environment. Collate User Data from the Screening Tool. As part of the ACRP Project 02-60 research, a screening tool was developed to assist airport representatives with understanding the poten- tial risks involved in procuring, storing, handling, and disposing of AFFF at their sites. The screening tool ranks user responses and provides valuation that is non-contextual, as there is no scale for comparison. Further research could collate user inputs and their results, creating an airport-specific scale that could then provide ranking that is relevant to airport owners and operators, improving the applicability of the screening tool to evaluate potential risks related to PFASs.
90 Use and potential Impacts of aFFF Containing pFaSs at airports Feasible, Cost-Effective Remediation Techniques and/or Approaches. The research showed that most remediation technologies did not work unilaterally for all PFASs, or had not been adequately demonstrated in field trials. It is recommended that prior to implementation of any remedial technology, feasibility studies be conducted during the remedial options process to allow airport managers to make decisions between the trade-offs of efficacy and cost.
