<scp>PFAS</scp> are forever? The state of the science and research needs for analyzing and treating <scp>PFAS</scp> ‐laden water

Readers will benefit from learning about the current status of PFAS sampling, analysis, and treatment techniques. The unique properties can cause problems when conducting basic bench or field studies. For instance, bottle choice is important not only for assuring accurate analytical measurements, but also design studies themselves. In this topical collection, Kleiner et al. (2021) assess practical implications using various materials in ion exchange (IX) activated carbon isotherm experiments. Silanized glass, polypropylene, high-density polyethylene (HDPE) were screened. It shown that five perfluoroalkyl sulfonic acids (PFSA) sorbed to HDPE bottles, linear isomers two PFSA exhibited enhanced adsorption relative corresponding branched isomers. From these results, guidance IX are developed. sampling field, a demonstrated passive technique would be extremely because vagaries concentrations seen natural environments. Hartmann demonstrate sampler used PFAS, including C4-C9 perfluorocarboxylates (PFCAs) C4, C6, C8 perfluorosulfonates (PFSAs) under variety solution conditions. uses PFAS-specific adsorbent tailored both hydrophobic interactions. an organosilica resin modified with cross-linked amine polymer addition groups combination Cu2+. samplers show integrated response concentration time all analytes tested except short-chain (i.e., C4 C5 PFCAs), relatively low variability rate over range conditions water matrices elevated ionic strength organic matter concentrations. Sampling times as short 3 days necessary reach detection limits <70 ng/L PFOA PFOS. Determination sources vital protect drinking sources. Andrews analyze potential environmental releases contaminated sites, currently active industrial waste disposal sites. EPA's Enforcement Compliance History Online (ECHO) database specific case Michigan California how source identification programs provide crucial information determining therefore aid developing effluent guidelines pretreatment programs. With regard analytic methods, at we started curating issue, available EPA Methods 537.1 533 developed water. These methods have been widely assessments lack ambient methods. To date, few published support expanding other matrices. Whitaker evaluate performance use potable nonpotable waters. Both found generally applicable analysis pristine However, biased recoveries notable issues long-chain those elute late reverse-phase column surface loss matrix. Also, there extraction concerns which matched isotopically labeled standards available. challenges successfully resolved reduced by enhancing post-extraction rinsing elution procedures. results illustrate challenge simultaneously analyzing extensive suite diverse properties. recently Draft Method 1633 targeting 40 aqueous solids tissue samples. method undoubtedly great interest many, albeit beyond scope collection. Combustion chromatography (CIC) has valuable tool determine total fluorine samples, such system commonly Wang, Abusallout, (2021), Yan, idea modifying analyzer—an instrument common laboratories across disciplines—as alternative approach. serve screening allow mass balance evaluation help overall percent mineralization destruction technologies. hydrogen fluoride evolving combusted samples captured impinger analyzed chromatography. limit based on spiked 36 μg-F/L (52 μg PFOA/L). River wastewater similar deionized identified some previously unknown limitations CIC methods: possible variable different chain lengths structures, inorganic during combustion. study emphasizes suitable removal techniques essential best define whether it total, organic, adsorbable fluorine. A deal work referenced articles technologies applied changed since became concern. include granular (GAC) adsorption, IX, filtration through high-pressure membranes—that is, nanofiltration (NF) reverse osmosis (RO) membranes. This understandable knowing length needed move novel technology into marketplace, especially if includes production given health consequences may occur designed poorly. need factor aspects certifying permitting new state primacy agencies. insignificant applications; however, dealing remediation waters, streams, landfill leachates, residual streams process (e.g., carbon, resins, NF/RO membranes), find niche they could expand applications future. Technologies besides GAC, membranes foam separation take advantage PFAS's propensity accumulate air/water interfaces onto clays biosolids; less expensive result ultimate PFAS. destructive removal, discussed issues, perhaps suited high streams. As recent research working advance application treatments. Communities struggled choices robust economical. true communities additional contaminants very small individual rural homes affected groundwater contamination, home systems option reduce exposure. treatment, household point-of-entry (POE) well-established. Natarajan test POE remove their precursors film-forming foam. expected literature, more effectively removed than PFCAs break before PFSAs same length. TOP assay highlights filter earlier measured PFSAs, general dissolved (DOC). Overall, conditions, studied filters 5 months effective measured, 7 select shorter-chain PFCAs. managing contamination. Also scale, Mulhern 18 private wells North Carolina, commercially-available point (POU) carbon-block certified NSF's P-473 protocol PFOS was successful removing 17 detected influent, ether (PFEAs). eight-month covered manufacturer's recommended lifetime device. Variations influent quality (pH 4.4–7.1, DOC 0.6–1.2 mg/L) did significant effect performance. demonstrates POU devices operated approach treating water, although data wider site-specific background affect higher capacities compared GAC; media costs unclear situation most cost-effective achieve final target any optimization resins need, regenerable resins. employed single-use Dietz regeneration efficiency strong-base anion concentrations, compositions, solutions. Generally, resulted loading efficiency, polystyrene resin. Polystyrene showed greater PFCAs, PFAAs analogs. presence cosolvents regenerant brine improved efficiency. Treatment models useful anticipating full-scale function situations change, varying flow rates, future goals. Compared GAC models, freely Haupert discuss theoretical considerations modeling gel-type, strong base batch processes. several literature preclude movement toward model development, inappropriate isotherms accounting non-equilibrium Theoretical presented researchers develop ion-exchange theory, designing interpreting Similarly, Kempisty (2022) 10 sub-bituminous, coal-based GACs bench-, pilot-, full-scales scale-up procedures effects PFAA characteristics rates. Batch tests pulverized perform similarly groundwater, larger mesopore volume proportional diffusivity rapid small-scale (RSSCTs) overpredicted capacity. rates decrease increasing lower No differences observed empty bed contact 13 26 min adsorbers RSSCT Based <25 mgGAC/Lwater treated criterion feasibility, field-scale adsorber suggest viable PFAAs. standard adsorbents accepted treatment; numerous formulations adsorbents. known contaminants. media's acceptability many performance, cost, operational requirements, impacts quality, regulatory acceptance. Li review functional bioadsorbents low-cost alternatives traditional adsorbents, particular authors nano-scale biosorbents derived properly functionalized manner raw biomass. biomass sorbents Najm three commercially bituminous one clay-based containing quaternary ammonium groups. initial breakthrough starting around 100,000 volumes PFBS (C4 PFSA) PFHxA (C6 PFCA), 50,000 volumes. adsorbent, appeared after 300,000 Similar sorbent shorter hydraulic GAC. Grieco theme presenting equilibrium emerging clay composition Under tested, flow-through experiments adsorptive capacity faster kinetics long- (PFOA) (PFBS). Adsorbent schemes plants produce subsurface control migration bentonite minimize leaching soils, long-term immobilizing anionic whereas preventing cationic Hardwood biochar, despite good minor negligible classes present soil slurry. shows options reducing soils continuous release certain poorly even clean There no clear difficult treat RO NF reject degree, processes do destroy concentrated stream. Therefore, prevent human exposure, possibly geographically distant locations. Tow wide destruction, concentration, sequestration strategies concentrate Cost paramount, membrane subsequent management strategy. retentate apply hard-to-treat waters wastewaters. identify approaches residuals non-destructive processes, Ryan electrochemical electrocoagulation electrooxidation. promising NF, much must completed account environmentally relevant conductivity, matter, transformation products, community's technical financial limitations. McCleaf examine fractionation leachate. Foam give efficiencies 90% PFOA, PFOS, PFHxS, PFHpA, 6:2 FTSA; between 50% 80% PFNA, PFPeS, PFHxA, PFHpS, PFBS; 20%–50% EtFOSAA, PFBA, PFDA, FOSA, PFPeA, MeFOSAA. Increased majority flowrate increased, iron (III) oxide coagulant added, conductivity applied. Wastewaters challenging considering reuse applications. Kumar City Altamonte Springs' demonstration facility. ozonation, biological filtration, ultrafiltration, UV advanced oxidation (greater carbons six PFCA) keep TOC levels below mg/L, Florida indirect reuse. Ozone followed increased due precursor material. determined critical TOC, trade-offs operation. Likewise, Gonzalez project Hampton Roads Sanitation District (HRSD), initiated recharge Potomac Aquifer. maintained (<8 ppt sum PFOS). Early PFHxA) mobility Aquifer strict measures guide United States, Safe Drinking Water Act authorizes set national health-based against naturally-occurring man-made Alfredo Relative Health Index (RHI) metric quantify ranges risk reductions federal threshold compare them previous determinations—for example, arsenic uranium—as well unregulated propose assumptions, number references meaningful reduction nationally (in States) historically established benchmarks occurrence data. decision-making public protection associated face uncertainty. Due absence of, differing, regulations, communicate clearly effectively. Such communication existing opinion complexity behaviors environment treatment. Harclerode community-specific adaptive strategy municipalities assessment mitigation activities while addressing community concerns. outreach addressed respective municipality's planned messages following actions. perception factors differed, hence likely cases. value engagement being conducted question remains mineralized put further harm public. Analytical improving areas, ability cover standardizing bring down cost level effort analysis. Measurement parameters helpful technique, offer helping close remain proven considered sites utilities, highly contaminated. specifics shaped factors. Each managed, still learned regarding reactivation, incineration, Other continue developed, hope up wastewaters, concentrates, Further needed. Thomas Speth: Writing – original draft; writing editing. Jinxia Liu: Detlef Knappe: Andrea Leeson: Zaid Chowdhury: Michelle Crimi: Jennifer Guelfo: Eric Dickenson: Data sharing article datasets generated editorial.