Remediation JournalEarly View COMMENTARY Editor's perspective—EPA's FY 2023 proposed budget's impact on remediation-related programs John A. Simon, Corresponding Author John A. Simon jsimon@gnarusllc.com Gnarus Advisors LLC, Washington, District of Columbia, USA Correspondence: John A. Simon, Gnarus Advisors LLC, 1906 35th St NW, Washington, DC 20007, USA. Email: jsimon@gnarusllc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@gnarusllc.com Gnarus Advisors LLC, Washington, District of Columbia, USA Correspondence: John A. Simon, Gnarus Advisors LLC, 1906 35th St NW, Washington, DC 20007, USA. Email: jsimon@gnarusllc.comSearch for more papers by this author First published: 14 June 2022 https://doi.org/10.1002/rem.21726Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Early ViewOnline Version of Record before inclusion in an issue RelatedInformation

Updating existing regional screening levels (RSLs) for three PFAS and adding new RSLs for three PFAS. Issuing revised interim drinking water health advisories for two PFAS and final health advisories for two PFAS. Announcing near-term proposed rulemaking to add two PFAS to EPA's list of hazardous substances. This Editor's Perspective summarizes these PFAS regulatory developments. Perfluorooctane sulfonic acid (PFOS); Perfluorooctanoic acid (PFOA); Perfluorobutane sulfonic acid (PFBS); Perfluorononanoic acid (PFNA); Perfluorohexane sulfonic acid (PFHxS); Hexafluoropropylene oxide dimer acid and its ammonium salt (referred to as GenX chemicals). Table 1 provides the pre-May 2022 RSLs along with those published in May 2022. While RSLs are not regulatory enforceable levels, they are often adopted by states when establishing drinking water standards or guidance and can form the basis for groundwater cleanup objectives, including consideration as preliminary remediation goals or PRGs at Superfund sites. For example, on July 6, 2022, the US Department of Defense (DoD) issued a Memorandum indicating that the PFAS RSLs should be used to determine if further investigation during the remedial investigation phase is warranted or if no further action is required (DoD, 2022). The EPA issued interim health advisories for PFOA and PFOS and final health advisories for PFBS and GenX chemicals on June 15, 2022, as shown in Table 2. It is interesting that GenX chemicals and PFBS were intended as replacements for the longer chain PFOA and PFOS, respectively, yet EPA is paving the way to have these chemicals regulated (note: EPA did not necessarily approve the use of GenX chemicals and PFBS as replacements to PFOA and PFOS). On July 19, 2022, a group of remediation professionals who conducted the Remediation-sponsored PFAS Experts Symposia in May 2019 and June/July 2021 provided a webinar, also sponsored by Remediation, discussing the impact of the health advisories issued in June 2022 as they pertain to the following remediation-related topics: regulations and policy, chemistry and analytics, toxicology and risk assessment, fate and transport, existing in situ and ex situ remediation technologies, and remediation research. Notably, as explained during the webinar, the health advisories for PFOA and PFOS are far below the EPA-required method detection limits of 4 ng/L and, in certain areas, may be above background groundwater conditions. EPA announced it will propose a National Primary Drinking Water Regulation by the end of 2022 for PFOA and PFOS that will include maximum contaminant levels (MCLs) and maximum contaminant level goals (MCLGs) with a plan of promulgating the regulation for PFOA and PFOS by the end of 2023. The MCLs will be the drinking water standards and the MCLG will be the level at which no known or anticipated adverse effect on the health of persons is anticipated to occur, including an adequate margin of safety. Many anticipate the health advisories to become the MCLGs and there remains uncertainty regarding the numerical values for the proposed MCLs. This is important to the remediation community because MCLs often become groundwater standards and also form the basis for soil remediation standards. Obviously, lower standards will be more costly to achieve and will challenge the ability of many sites to reach closure (particularly because of the extreme recalcitrance of both PFOA and PFOS under ambient conditions). The EPA announced that as the Agency works on the proposed drinking water regulations for PFOA and PFOS, it will also be evaluating drinking water standards for additional PFAS and is considering actions to address groups of PFAS. Releases of PFOA and PFOS that meet or exceed the reportable quantity (to be included as part of the regulation) must be reported to the National Response Center, state or Tribal emergency response commissions, and the local or Tribal emergency planning committees. The EPA has not yet proposed the reportable quantity triggers. EPA may list additional Superfund sites on the National Priority List based on risks posed by PFAS. Additionally, EPA will be able to unilaterally order removal actions for imminent and substantial endangerment to public health or the environment due to PFAS contamination. The hazardous substance designation could complicate existing CERCLA removal actions and remedial actions underway for non-PFAS contamination by expanding investigation and response activities to address PFAS. EPA currently requires PFAS sampling as part of many 5-year Superfund site reviews; PFAS detections could trigger the need for supplemental remedial actions. The hazardous substance designation could potentially affect ongoing Superfund site allocation share proceedings between responsible parties because of the impact on remedial action costs as well as changing the landscape of how parties' discharges affect cleanup costs in the context of cost causation models due to the presence of PFAS. There is a distinct possibility that the portion of the remedial action cost associated with the presence of PFAS could change allocation shares among responsible parties. For example, under cost causation allocation models, due to the toxicity (toxicity leads to low cleanup goals), mobility, and recalcitrance of many PFAS, the remediation costs could increase with the PFAS-related parties having larger allocated shares of the overall costs than they would have otherwise without the presence of PFAS. With a hazardous substance designation, EPA and states can initiate CERCLA Section 107 cost-recovery claims for PFAS-related response actions. Furthermore, the designation would enable private party cost-recovery (Section 107) and contribution (Section 113(f)) response action costs claims related to the presence of PFAS. The PFAS Experts Symposium Group is planning another webinar summarizing the impacts and issues surrounding the hazardous substance designation to explain and discuss EPA's proposed rule. There is an atmosphere of uncertainty with respect to how these recent EPA actions will impact PFAS site investigations and remediation. As illustrated by the DoD's July 2022 policy, the new RSLs have already affected how PFAS data are evaluated in the investigation context at military installations. As presented in the PFAS Experts webinar in July 2022, the new health advisories add complexity to PFAS remediation projects as there is ambiguity how states will use the health advisories and, when available, MCLs to establish cleanup standards, whether the MCLs will impact the extent and costs of cleanups, and whether cleanups will be required for GenX chemicals and PFBS, which were intended to be replacements for PFOA and PFOS. Designating PFAS as a hazardous substance is likely to have considerable impacts at Superfund remedial and removal action sites where PFAS are detected, including expanding investigations and cleanups and complicating allocation proceedings. Finally, the three EPA actions summarized above are only a portion of EPA's PFAS-related activities as the Agency implements its PFAS Action Plan published in February 2019 (EPA, 2019) that the Agency updated in February 2020 (EPA, 2020). Other EPA actions potentially relevant to the remediation community that are part of EPA's PFAS Strategic Roadmap include: requiring public water supply systems to conduct PFAS testing under the Fifth Unregulated Contaminant Monitoring Rule from 2023 to 2025, publishing draft aquatic life water quality criteria for PFOA and PFOS (April 2022), additional toxicity assessments, expanding EPA-approved PFAS laboratory methods, completing a risk assessment for PFAS in biosolids, and regulating PFAS discharges to surface water under the National Pollutant Discharge Elimination System (EPA, 2021c). John A. Simon is the editor-in-chief of Remediation. He is also a Principal at Gnarus Advisors (Washington, DC), a consulting firm specializing in providing advisory and litigation support services for environmental and economic matters.

Remediation JournalVolume 32, Issue 1-2 p. 5-8 COMMENTARY Editor's Perspective—PFAS update: Recent developments based on PFAS Experts Symposium 2 John A. Simon, Corresponding Author John A. Simon [email protected] Gnarus Advisors LLC and Remediation, Washington, DC, USA Correspondence John A. Simon, Gnarus Advisors LLC and Remediation, 1906 35th St NW, Washington, DC 20007, USA. Email: [email protected]Search for more papers by this author John A. Simon, Corresponding Author John A. Simon [email protected] Gnarus Advisors LLC and Remediation, Washington, DC, USA Correspondence John A. Simon, Gnarus Advisors LLC and Remediation, 1906 35th St NW, Washington, DC 20007, USA. Email: [email protected]Search for more papers by this author First published: 27 January 2022 https://doi.org/10.1002/rem.21708Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume32, Issue1-2Spring 2022Pages 5-8 This article also appears in:PFAS Experts Symposium 2021 RelatedInformation

Remediation JournalVolume 31, Issue 4 p. 3-5 EDITOR'S PERSPECTIVE Editor's perspective—Recent developments in green and sustainable remediation John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Gnarus Advisors LLC, Washington, DC, USA Correspondence John A. Simon, Gnarus Advisors LLC, Washington, DC 20007 USA. Email: jsimon@gnarusllc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Gnarus Advisors LLC, Washington, DC, USA Correspondence John A. Simon, Gnarus Advisors LLC, Washington, DC 20007 USA. Email: jsimon@gnarusllc.comSearch for more papers by this author First published: 13 September 2021 https://doi.org/10.1002/rem.21701Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume31, Issue4Fall 2021Pages 3-5 RelatedInformation

Remediation JournalVolume 31, Issue 3 p. 3-6 EDITOR'S PERSPECTIVE Editor's perspective—Highlights of recent remediation technology innovations published in Remediation John A. Simon, Corresponding Author jsimon@nathaninc.com Nathan Associates Inc., Arlington, Virginia, USA Correspondence John A. Simon, Nathan Associates Inc., Arlington, VA 22209, USA. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author jsimon@nathaninc.com Nathan Associates Inc., Arlington, Virginia, USA Correspondence John A. Simon, Nathan Associates Inc., Arlington, VA 22209, USA. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 16 June 2021 https://doi.org/10.1002/rem.21690Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Volume31, Issue3Summer 2021Pages 3-6 RelatedInformation

Remediation JournalVolume 30, Issue 2 p. 3-4 EDITOR'S PERSPECTIVE Editor's perspective—Just how large is the PFAS problem? John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Arlington, Virginia Correspondence John A. Simon, 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Arlington, Virginia Correspondence John A. Simon, 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 28 February 2020 https://doi.org/10.1002/rem.21643Citations: 3Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume30, Issue2Spring 2020Pages 3-4 RelatedInformation

Remediation JournalVolume 30, Issue 4 p. 3-5 EDITOR'S PERSPECTIVE Editor's perspective—U.S. EPA's 2020 Superfund remedy report shows distinctive trends in remediation technologies John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Arlington, Virginia, USA Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent St, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Arlington, Virginia, USA Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent St, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 15 September 2020 https://doi.org/10.1002/rem.21665Citations: 2Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume30, Issue4Fall 2020Pages 3-5 RelatedInformation

Remediation JournalVolume 31, Issue 1 p. 3-4 EDITOR'S PERSPECTIVE Editor's perspective—Anticipated changes to USEPA's cleanup programs under the Biden administration John A. Simon, Corresponding Author jsimon@nathaninc.com Nathan Associates and Remediation Journal, Arlington, Virginia, USA Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent St, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author jsimon@nathaninc.com Nathan Associates and Remediation Journal, Arlington, Virginia, USA Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent St, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 21 December 2020 https://doi.org/10.1002/rem.21671 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume31, Issue1Winter 2020Pages 3-4 RelatedInformation

Remediation JournalVolume 30, Issue 3 p. 3-5 EDITOR'S PERSPECTIVE Editor's perspective: COVID-19's impact on the remediation industry John A. Simon, Corresponding Author John A. Simon [email protected] Nathan Associates and Remediation Journal, Arlington, Virginia Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent St, Arlington, VA 22209. Email: [email protected]Search for more papers by this author John A. Simon, Corresponding Author John A. Simon [email protected] Nathan Associates and Remediation Journal, Arlington, Virginia Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent St, Arlington, VA 22209. Email: [email protected]Search for more papers by this author First published: 09 June 2020 https://doi.org/10.1002/rem.21655Citations: 4Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. REFERENCES Beniac, D. R., Andonov, A., Grudeski, E., & Booth, T. F. (2006). Architecture of the SARS coronavirus prefusion spike. Nature Structural & Molecular Biology, 13(751–752), 2006–752. Google Scholar Blattner, W., Hunt, N. C., Lundber, B., & Kreitner, J. (2020, March). COVID-19 Environmental Enforcement Discretion Policies: U.S. EPA & 50-State Guide. Columbus, OH: Thompson Hine LLP. Retrieved from: https://www.thompsonhine.com/uploads/1135/doc/COVID19_USEPA_50_State_Enforcement_Guide.pdf Google Scholar Bodine, S. P. (2020). Memorandum: COVID-19 implications for EPA's enforcement and compliance assurance program. Washington, DC: U. S. Environmental Protection Agency. Google Scholar California Environmental Protection Agency (2020, April). CalEPA issues statement on compliance with regulatory requirements during the COVID-19 emergency. Retrieved from: https://calepa.ca.gov/2020/04/15/calepa-statement-on-compliance-with-regulatory-requirements-during-the-covid-19-emergency/ Google Scholar Fehr, A. R., & Perlman, S. (2015). Coronaviruses: An overview of their replication and pathogenesis. In H. J. Maier, E. Bickerton & P. Britton (Eds.), Coronaviruses: Methods and protocols (pp. 1–23). New York, NY: Humana Press. 10.1007/978-1-4939-2438-7_1 Google Scholar Murphy, P. D. (2020, February). Executive order no. 107. Trenton, NJ: State of New Jersey. Retrieved from: https://nj.gov/infobank/eo/056murphy/pdf/EO-122.pdf Google Scholar U.S. Environmental Protection Agency (2020). EPA takes action to guide health and safety decisions at cleanup sites during the COVID-19 pandemic. Retrieved from: https://www.epa.gov/newsreleases/epa-takes-action-guide-health-and-safety-decisions-cleanup-sites-during-covid-19 Google Scholar U.S. Food and Drug Administration (2020). Enforcement policy for sterilizers, disinfectant devices, and air purifiers during the coronavirus disease 2019 (COVID-19), public health emergency guidance for industry and Food and Drug Administration staff. Washington, DC: U. S. Department of Health and Human Services. Google Scholar Wright, P. C., & Bodine, S. P. (2020). Memorandum: Interim guidance on site field work decisions due to impacts of COVID-19, Washington, DC: U. S. Environmental Protection Agency. Google Scholar Citing Literature Volume30, Issue3Summer 2020Pages 3-5 ReferencesRelatedInformation

Remediation JournalVolume 30, Issue 1 p. 3-4 EDITOR'S PERSPECTIVE Editor's Perspective: Evaluation of Superfund Task Force recommendations from a remediation professional's perspective John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Arlington, Virginia Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Arlington, Virginia Correspondence John A. Simon, Nathan Associates and Remediation Journal, 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 03 December 2019 https://doi.org/10.1002/rem.21634Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume30, Issue1Winter 2019Pages 3-4 RelatedInformation

Remediation JournalVolume 29, Issue 3 p. 3-3 EDITOR'S PERSPECTIVE Editor’s perspective—Remediation field’s continued evolution John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Inc, Arlington, Virginia Correspondence John A. Simon, Nathan Associates, Inc., 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Inc, Arlington, Virginia Correspondence John A. Simon, Nathan Associates, Inc., 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 20 June 2019 https://doi.org/10.1002/rem.21607Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume29, Issue3Summer 2019Pages 3-3 RelatedInformation

Sixty leading members of the scientific, engineering, regulatory, and legal communities assembled for the PFAS Experts Symposium in Arlington, Virginia on May 20 and 21, 2019 to discuss issues related to per- and polyfluoroalkyl substances (PFAS) based on the quickly evolving developments of PFAS regulations, chemistry and analytics, transport and fate concepts, toxicology, and remediation technologies. The Symposium created a venue for experts with various specialized skills to provide opinions and trade perspectives on existing and new approaches to PFAS assessment and remediation in light of lessons learned managing other contaminants encountered over the past four decades. The following summarizes several consensus points developed as an outcome of the Symposium: Regulatory and policy issues: The response by many states and the US Environmental Protection Agency (USEPA) to media exposure and public pressure related to PFAS contamination is to relatively quickly initiate programs to regulate PFAS sites. This includes the USEPA establishing relatively low lifetime health advisory levels for PFAS in drinking water and even more stringent guidance and standards in several states. In addition, if PFAS are designated as hazardous substances at the federal level, as proposed by several Congressional bills, there could be wide-reaching effects including listing of new Superfund sites solely for PFAS, application of stringent state standards, additional characterization and remediation at existing sites, reopening of closed sites, and cost renegotiation among PRPs. Chemistry and analytics: PFAS analysis is confounded by the lack of regulatory-approved methods for most PFAS in water and all PFAS in solid media and air, interference with current water-based analytical methods if samples contain high levels of suspended solids, and sample collection and analytical interference due to the presence of PFAS in common consumer products, sampling equipment, and laboratory materials. Toxicology and risk: Uncertainties remain related to human health and ecological effects for most PFAS; however, regulatory standards and guidance are being established incorporating safety factors that result in part per trillion (ppt) cleanup objectives. Given the thousands of PFAS that may be present in the environment, a more appropriate paradigm may be to develop toxicity criteria for groups of PFAS rather than individual PFAS. Transport and fate: The recalcitrance of many perfluoroalkyl compounds and the capability of some fluorotelomers to transform into perfluoroalkyl compounds complicate conceptual site models at many PFAS sites, particularly those involving complex mixtures, such as firefighting foams. Research is warranted to better understand the physicochemical properties and corresponding transport and fate of most PFAS, of branched and linear isomers of the same compounds, and of the interactions of PFAS with other co-contaminants such as nonaqueous phase liquids. Many PFAS exhibit complex transport mechanisms, particularly at the air/water interface, and it is uncertain whether traditional transport principles apply to the ppt levels important to PFAS projects. Existing analytical methods are sufficient when combined with the many advances in site characterization techniques to move rapidly forward at selected sites to develop and test process-based conceptual site models. Existing remediation technologies and research: Current technologies largely focus on separation (sorption, ion exchange, or sequestration). Due to diversity in PFAS properties, effective treatment will likely require treatment trains. Monitored natural attenuation will not likely involve destructive reactions, but be driven by processes such as matrix diffusion, sorption, dispersion, and dilution. The consensus message from the Symposium participants is that PFAS present far more complex challenges to the environmental community than prior contaminants. This is because, in contrast to chlorinated solvents, PFAS are severely complicated by their mobility, persistence, toxicological uncertainties, and technical obstacles to remediation-all under the backdrop of stringent regulatory and policy developments that vary by state and will be further driven by USEPA. Concern was expressed about the time, expense, and complexity required to remediate PFAS sites and whether the challenges of PFAS warrant alternative approaches to site cleanups, including the notion that adaptive management and technical impracticability waivers may be warranted at sites with expansive PFAS plumes. A paradigm shift towards receptor protection rather than broad scale groundwater/aquifer remediation may be appropriate.

In 2009, the Sustainable Remediation Forum released a white paper entitled “Integrating sustainable principles, practices, and metrics into remediation projects” (Ellis & Hadley, 2009, Remediation , 19, pp. 5–114). Sustainable remediation was a relatively new concept, and the white paper explored a range of approaches on how sustainability could be integrated into traditional remediation projects. This paper revisits the 2009 white paper, providing an overview of the early days of the evolving sustainable remediation practice and an assessment of the progress of sustainable remediation over the last 10 years with a primary focus on the United States. The current state of the sustainable remediation practice includes published literature, current practices and resources, applications, room for improvement, international progress, the virtuous cycle that applying sustainable remediation creates, and the status of the objectives cited in the 2009 white paper. Over the last decade, several sustainable remediation frontiers have emerged that will likely be a focus in advancing the practice. These frontiers include climate change and resiliency, weighting and valuation to help better consolidate different sustainable remediation metrics, programmatic implementation, and better integration of the societal impacts of sustainable remediation. Finally, as was the case for the 2009 white paper, this paper explores how sustainable remediation may evolve over the next 10 years and focuses on the events and drivers that can be significant in the pace of further development of the practice. The events and drivers include transformation impacts, societal influences, and the continued development of new technologies, approaches, and tools by remediation practitioners. The remediation industry has made significant progress in developing the practice of sustainable remediation and has implemented it successfully into hundreds of projects. While progress has been significant, an opportunity exists to implement the tenets of sustainable remediation on many more projects and explore new frontiers to help improve the communication, integration, and derived benefits from implementing sustainable remediation into future remediation projects.

Remediation JournalVolume 29, Issue 2 p. 3-5 EDITOR'S PERSPECTIVE The unprecedented rate of developments concerning PFAS issues John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Inc., Arlington, Virginia Correspondence John A. Simon, Nathan Associates, Inc., 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates, Inc., Arlington, Virginia Correspondence John A. Simon, Nathan Associates, Inc., 1777 N. Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 28 February 2019 https://doi.org/10.1002/rem.21594Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume29, Issue2Spring 2019Pages 3-5 RelatedInformation

Remediation JournalVolume 29, Issue 4 p. 3-3 EDITOR'S PERSPECTIVE Editor's perspective—PFAS Experts Symposium identifies problematic issues with the state of PFAS science, remediation technologies, and policy John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates and Remediation Journal, Arlington, Virginia Correspondence John A. Simon, Nathan Associates and Remediation Journal,1777 N. Kent Street,Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Nathan Associates and Remediation Journal, Arlington, Virginia Correspondence John A. Simon, Nathan Associates and Remediation Journal,1777 N. Kent Street,Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 11 September 2019 https://doi.org/10.1002/rem.21625Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume29, Issue4Autumn 2019Pages 3-3 RelatedInformation

Remediation JournalVolume 29, Issue 1 p. 3-5 EDITOR'S PERSPECTIVE Commentary: Climate change resiliency in remediation John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Correspondence John A. Simon, Nathan Associates Inc., 1777 N. Kent Street, Suite 1400, Arlington, VA 22209.Search for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Correspondence John A. Simon, Nathan Associates Inc., 1777 N. Kent Street, Suite 1400, Arlington, VA 22209.Search for more papers by this author First published: 04 December 2018 https://doi.org/10.1002/rem.21584Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume29, Issue1Winter 2018Pages 3-5 RelatedInformation

Remediation JournalVolume 28, Issue 3 p. 3-6 EDITOR'S PERSPECTIVE Editor's perspective—Fascinating issues and complexities associated with polycyclic aromatic hydrocarbons John A. Simon, Corresponding Author John A. Simon Jsimon@nathaninc.com Nathan Associates, Arlington, VA Correspondence John A. Simon, Nathan Associates Inc., 1777 North Kent Street, Arlington, VA 22209. Email: Jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon Jsimon@nathaninc.com Nathan Associates, Arlington, VA Correspondence John A. Simon, Nathan Associates Inc., 1777 North Kent Street, Arlington, VA 22209. Email: Jsimon@nathaninc.comSearch for more papers by this author First published: 06 June 2018 https://doi.org/10.1002/rem.21556Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Volume28, Issue3Summer 2018Pages 3-6 RelatedInformation

Remediation JournalVolume 28, Issue 4 p. 3-3 EDITOR'S PERSPECTIVE Editor's perspective John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Correspondence John A. Simon, Nathan Associates, 1777 North Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author John A. Simon, Corresponding Author John A. Simon jsimon@nathaninc.com Correspondence John A. Simon, Nathan Associates, 1777 North Kent Street, Arlington, VA 22209. Email: jsimon@nathaninc.comSearch for more papers by this author First published: 06 September 2018 https://doi.org/10.1002/rem.21570Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume28, Issue4Autumn 2018Pages 3-3 RelatedInformation