Technology Innovation News Survey

U.S. Army Corps of Engineers, Engineer Division Northwestern, Seattle District, Seattle, WA
Contract Opportunities on SAM.gov W912DW25R0008_SS3, 2025

This is a sources sought notice for marketing research purposes only. The U.S. Army Corps of Engineers Seattle District is seeking interested business sources for the Formosa Mine Remedial Action Capping Project in Riddle, Oregon under NAICS code 562910. The project scope of work consists of activities necessary to implement primarily the earthwork-related requirements of the EPA's RoD for the Formosa Mine Superfund Site OU1. OU1 includes all surface and subsurface mine materials deposited outside of the underground mine workings and considered source materials for the site, including materials excavated during construction and mine operation. Objectives are to remove, consolidate, and restrict or minimize the interaction of contaminant source materials with precipitation, surface water runoff, and groundwater. The remedial approach focuses on preventing direct exposure to mine waste with elevated metal concentrations and reducing acid rock drainage generation, reducing impacts on groundwater and surface water. The proposed project award will be a firm-fixed-price contract and is predominantly construction. The magnitude is estimated to be in the range of $25,000,000 and $100,000,000. 100% payment and performance bonds will be required. Capability packages are due by 2:00 PM PDT on June 20, 2025. https://sam.gov/opp/b19db9b1b2c34773a70e1ba6ec3c5a86/view

U.S. Environmental Protection Agency, Region 9 Contracting Office, San Francisco, CA
Contract Opportunities on SAM.gov 68HE0925Q0003, 2025

When this solicitation is released sometime in June or July 2025, it will be competed as a full and open competition under NAICS code 562910. EPA Region 9 Contracting Office plans to issue a solicitation for support of its Water Emergency and Rapid Response Services contract. The purpose of the Water Emergency and Rapid Response Services contract is to provide consistent services to EPA and other federal officials implementing EPA's responsibilities, and fast support to drinking water and wastewater utilities located in EPA Region 9 during emergencies resulting from natural and manmade disasters, terrorist activities, weapons of mass destruction, and nuclear, biological or chemical incidents. These responsibilities are described in the background below. The contractor shall fulfill these responsibilities within the region as well as outside the region on a backup regional response, cross-regional response, and national response. For each assigned task, the contractor shall provide appropriately experienced, trained, and accredited personnel with current credentials/certifications, as well as all supplies, materials, tools, and equipment necessary to complete the job. The contractor shall take any actions required to restore water and wastewater services including emergency repairs to infrastructure; isolation of contaminated facilities or pipelines; or general mitigation strategies to correct damage from Natural or man-made disasters. Technical requirements under this contract include emergency response, sampling, monitoring, site stabilization, controlling spilled material, waste treatment, restoration, removal actions, transportation, treatment and disposal. There is no solicitation at this time. https://sam.gov/opp/ac97f6526d0f4e158c3cce81e3b5344c/view

U.S. Army Corps of Engineers, Northwestern Division, Kansas City District, Kansas City, MO
Contract Opportunities on SAM.gov PANNWD25P0000005963, 2025

This is a sources sought notice for marketing research purposes only. The U.S. Army Corps of Engineers seeks to determine the interest of small businesses qualified to conduct remedial action activities at the Former Kil-Tone Superfund Site, Operable Unit 2, in Vineland, New Jersey under NAICS code 562910. The Former Kil-Tone Company site consists of ~4 acres in a mixed residential and commercial area. The company manufactured pesticides, which included arsenic and lead, from ~1917 to 1926. In 1926, the property was sold to Lucas Kil-Tone Co., a New Jersey company, which continued to manufacture pesticides at the property until at least 1933. This project addresses the remediation of OU2 property soils included in Phase 2, which is excavation of contaminated soils from non-residential property. The remedial action selected in the Record of Decision (ROD) dated September 2019 for OU2 soils includes: excavation of contaminated soil from properties within the vicinity of the FKTC property; off-site disposal of excavated contaminated soil, and backfilling of excavated areas with clean fill; and restoration of the affected properties. Responses are due by 5:00 PM CDT on June 30, 2025. https://sam.gov/opp/6c3a99fc503848ed9270f37ba9704c04/view

Kennington, B. and G. Guyer. ǀ DCHWS East 2025 Spring Symposium, 2-4 April, Philadelphia, PA, 15 slides, 2025

Close to 200,000 drums of pesticide manufacturing waste containing carbon tetrachloride, chloroform, alcohols, and ketones were disposed of in open, unlined trenches in the South, Middle, and North disposal areas at the Hardeman County Landfill. Contamination from the waste drums migrated into the underlying unconfined drinking water aquifer. Initial remedial actions consisted of the construction of low-permeability landfill caps coupled with installation and operation of a P&T system for hydraulic containment and treatment of contaminated groundwater. SVE pilot testing performed at the 1-acre South Disposal Area (SDA) led to an amended ROD for source area depletion using SVE to treat the residual contamination in the vadose zone at the Middle Disposal Area (MDA) and North Disposal Area (NDA). The design, construction and operation of the MDA were critical in generating lessons learned that can be applied to the NDA, including flexibility in the design to assist in managing change in future SVE operations. A phased approach was developed to address the geographical size and mass of contaminants at the NDA. The phased approach also provided operational flexibility and the ability to properly manage anticipated changes during remediation. The original design objective included storage and disposal of brine wastewater at offsite disposal facilities via truck transport; however, an onsite brine reduction system was completed as an addendum to the design. Since that time, there have been changes in both the practicality and availability of brine disposal facilities, as well as a reduction in anticipated transportation and disposal costs. It was ultimately decided that eliminating the BRS was the most practical and cost-effective method, resulting in a pending addendum to the design. https://mediacdn.guidebook.com/upload/213716/xdFKc4QRvUWHNer09OHmNQgJRqPySqdOYyMx.pdf

Krueger, J. and J. Cole. ǀ DCHWS East 2025 Spring Symposium, 2-4 April, Philadelphia, PA, 18 slides, 2025

An ongoing application of ISTT at the NASA Marshall Space Flight Center (MSFC) provides a case study in adaptive design for thermal treatment technology implementation. Subsurface contamination at source area SA-13 originated from a concrete pad used to store drums of spent chlorinated solvents, primarily TCE. DNAPL is encountered in select locations; however, the volume of solvents historically released from the pad remains unknown. Subsurface conditions at SA-13 are heterogeneous, consisting of ~35 feet of clayey residuum overlying a 5-foot-thick, water-bearing interval composed of gravel, sand, and clay on top of weathered limestone bedrock. The permeability of the residuum increases with depth and spans several orders of magnitude. Water is typically encountered near the top of bedrock, forming a regional karst groundwater system with a variable degree of hydraulic connection to the residuum. https://mediacdn.guidebook.com/upload/213716/0gqWuRGlM729Hxuae0Joa7V2Er5FrB2RCr1J.pdf

Yezuita, B. ǀ DCHWS East 2025 Spring Symposium, 2-4 April, Philadelphia, PA, 14 slides, 2025

The remedial action (RA) program for the Commerce Street Plume Superfund site is underway, funded by an EPA Bipartisan Infrastructure Law grant. Contaminants of concern include TCE and its breakdown products, which are present in a shallow sandy aquifer above an impermeable clay layer at ~40 ft bgs. The remedial design detailed the installation of five in situ treatment barriers using bioremediation amendment injection in the hotspot where TCE was >10,000 ppb and zero-valent iron was emplaced in downgradient trenches where TCE was >500 ppb. Six years after design-related investigation and a field pilot ISB injection program, an intensive pre-RA characterization was conducted to provide an updated extent of contamination and inform full-scale treatment barrier installation. This effort was enhanced with advanced 3D visualization to update the conceptual site model in real time and guide subsequent characterization elements. Recent data from wells near the pilot injection program indicate sustained performance of the ISB amendment, which increased confidence in the full-scale ISB application and refined expectations for injection frequency. https://mediacdn.guidebook.com/upload/213716/OLNO35GoYgVH5eWkrWPpU6z9QkTGZXspmh9A.pdf

Bracken, J. ǀ DCHWS East 2025 Spring Symposium, 2-4 April, Philadelphia, PA, 20 slides, 2025

ISS technology was determined to be the most cost-effective option to remediate a former auto salvage/metal scrap recycling facility with a complex combination of varying comingled contamination from a century's worth of discharges and releases, including tar/creosote, free/residual petroleum product, VOCs, SVOCs/PAHs, metals, pesticides, and PCBs. Several bench-scale/pilot tests were conducted to confirm the viability of ISS and develop the sitewide design criteria to address the mixed contamination. Bucket mixing techniques were implemented to the top of bedrock at depths up to 20 ft bgs. The site presented multiple challenges to meet remedial objectives due to various contaminants mixed with product, planned site redevelopment, concentration gradients in various source areas across the site, complexity of soil/material lithology, shallow groundwater, weathered/fractured bedrock, physical site constraints and access to treatment zones, proximity to sensitive receptors such as wetlands and neighboring properties, and client and developer schedule demands. The ISS treatment design was tailored to stabilize and contain source contamination of ~150,000 yd³ across the site. Mix designs were adjusted to address varying contaminant concentrations identified during remedial activities. ISS design criteria were also modified to address ISS cell failures, reduce and/or eliminate offsite disposal, and account for the developer foundation design, while maintaining the project schedule. https://mediacdn.guidebook.com/upload/213716/6Oz3LPpxmDcTKTQKQNkM1gEzItSoTC4F6avS.pdf

Strathmann, T. SERDP Project ER18-1063, 2 pp, 2023 (published 4/15/25)

Results from this SERDP Project support the conclusion that anion exchange resins (AERs), especially PFAS-selective single-use resins, are highly effective for treating PFAS-impacted groundwater. Pilot study results comparing three different polystyrene-based single-use AER (Calgon CalRes 2301, Dowex PSR2+, and Purolite PFA694E) at a DoD site in the Willow Grove, PA area showed that all three resins performed similarly, and significantly outperformed two more traditional regenerable AER, particularly for treatment of long-chain PFCAs and PFSAs. No detectable concentrations of >C7 PFCA or PFSA were observed within 150,000 bed volumes after treatment with the single-use resins (2-min electron-beam computed tomography). Although granular activated carbon (GAC) adsorbents were not included in the pilot study, results from the literature consistently showed that the same PFAS will breakthrough GAC adsorber beds much more quickly and media usage rates for GAC will be much greater than for PFAS-selective AERs. Both PFAS-selective and regenerable AER are less effective in treating shorter-chain PFCA, and differences in breakthrough relative to GAC may be expected to be less pronounced. Advantages of AER at sites where strict treatment of shorter-chain PFCA is also required may not be sufficient to offset the higher costs of these resins compared to GAC media.
Fact sheet: https://sepub-prod-0001-124733793621-us-gov-west-1.s3.us-gov-west-1.amazonaws.com/s3fs-public/2025-04/ER18-1063%20Fact%20Sheet.pdf?VersionId=pn_avQXzaWCNi0M_jfknstakFZVLVF_T
Final Report: https://sepub-prod-0001-124733793621-us-gov-west-1.s3.us-gov-west-1.amazonaws.com/s3fs-public/2023-11/ER18-1063%20Final%20Report.pdf?VersionId=eeej2612jWHAXcOeShGhbFGRm7q2FGKJ
Executive Summary:https://sepub-prod-0001-124733793621-us-gov-west-1.s3.us-gov-west-1.amazonaws.com/s3fs-public/2023-11/ER18-1063%20Executive%20Summary.pdf?VersionId=Aq74ecz991zMxGQXKC5UrJ7MbZk2P45e

Rathmell, S. ǀ AEHS Foundation 40th Annual International Conference on Soils, Sediments, Water and Energy 21-24 October, Amherst, MA, 19 slides, 2024

A field pilot test at a site in Connecticut with soil and groundwater impacted by CVOCs was implemented to address ecological concerns associated with subsurface impacts. The ongoing source area mass is sustaining a groundwater plume that has the potential to impact a nearby surface water body. High-resolution site characterization delineation of source and plume areas was used in conjunction with 3D modeling (using EVS software) to guide the targeted in situ remediation design. The in situ chemical reduction (ISCR) remediation approach utilized emulsified zero-valent iron (EZVI) for direct source mass (DNAPL) destruction. Permeable reactive barriers were installed using ZVI slurry emplacement via direct push drilling technology and injection to create ISCR reactive zones downgradient from the source treatment area to address CVOC-impacted groundwater. The presentation discusses site characteristics, technology selection, and the remediation approach design, including performance monitoring results over 18 months for source and plume treatment areas. https://s3.amazonaws.com/amz.xcdsystem.com/A51108D5-FA2F-2B6D-01D92AC0F42DCE3B_abstract_File24087/Handout_218_1018014826.pdf

Higgins, R.J., H.S. Kim, E. Houtz, P. Newman, D. Casey, and Y.I. Cho.
CS EST Water 5(5):2110-2119(2025)

The feasibility of remediating PFAS-contaminated groundwater using a combined regenerable ion exchange (IX) and plasma treatment approach was investigated at Joint Base Cape Cod in Massachusetts. Regenerable IX treated ~1,200,000 L of groundwater, meeting the treatment goal of 20 ng/L for Σ perfluorooctanesulfonate, perfluorooctanoate, perfluorohexanesulfonate, perfluorononanoate, perfluorheptanoate, and perfluorodecanoate. After IX media regeneration with a solvent brine solution, 45 L of a distilled PFAS concentrate ("still bottom") containing ~640 mg/L total PFAS was recovered, representing an overall process concentration factor of ~30,000. A novel plasma vortex technology employed for PFAS in the still bottom destroyed 97% of the PFAS initially present in 25% diluted still bottoms, with 99% of the destroyed PFAS recovered as inorganic fluoride. The energy consumption of the plasma vortex process treating the dilute still bottoms was 1,885 kW h/m3, or 12,140 kW h/kg PFAS destroyed. The treated still bottom was further reduced to nondetectable PFAS levels using reverse osmosis treatment, with the retentate returned to the plasma treatment system, thus creating a completely closed loop for plasma-treated regenerant waste with no liquid discharge. https://pubs.acs.org/doi/epdf/10.1021/acsestwater.4c00863?ref=article_openPDF

AECOM Technical Services, Inc. for NASA's Environmental Assurance Branch, 425 pp, 2025

A PlumeStop injection event was completed at the Base Support Building at 12 locations to create a permeable reactive barrier (PRB). The specific goals of the pilot study were to observe changes in PFAS mass flux in groundwater downgradient of the PlumeStop PRB; determine whether groundwater flow is being diverted around or under the PRB; and acquire design parameters necessary for future remedial design activities. Injection parameter data were recorded during the injection event to provide design parameters for future injection activities. Field measurements and observations collected during the injection events supported a conservative estimate for a lateral radius of influence (ROI) of 5 ft and a downgradient ROI of 6 ft. Data collected before and after the pilot study indicated that there were no changes in groundwater velocity or direction. This report summarizes performance monitoring data collected on November 1, 2024, and January 28, 2025, respectively. Groundwater samples were collected from the 14 pilot study wells during the events and analyzed for PFAS compounds, total organic carbon, and/or aluminum. PFAS concentrations were compared to EPA's MCL or the EPA Regional Screening Levels for tap water if no MCL was available. The PRB appears to be effective in reducing PFAS concentrations in groundwater within the PRB and over time, in groundwater downgradient of the PRB. Continued sampling is expected to confirm the long-term efficacy of a CAC PRB. https://ntrs.nasa.gov/api/citations/20250003144/downloads/BSB_Plumestop_Pilot_Update_Report-signed.pdf

Huang, C., R. Lewis, S. Thomas, Z. Tang, J. Jones, S. Nason, N. Zuverza-Mena, Z. Piskulich, T. O'Keefe, B. Tuga, A. Paredes-Beaulieu, V. Vasiliou, Q. Cui, J. Dalluge, J. White and C. Haynes.
ACS Nano 19(21):19777-19789(2025)

A study developed surface-modified ultraporous mesostructured silica nanoparticles (UMNs) to facilitate PFAS phytoremediation. UMNs were synthesized and functionalized to tune their hydrophobicity and surface charge to enhance their affinity for PFAS. Dynamic light scattering, sigma-potential, and nitrogen physisorption show that the modified UMNs had similar physical characteristics. Liquid chromatography-tandem mass spectrometry analysis shows that positively charged UMNs have a higher affinity for PFAS than negatively charged UMNs (with 20% of PFOA remaining in solution vs 100% of PFOA remaining in solution, respectively). When incubated with multiple PFAS, UMNs show greater removal efficiency for longer-chain and more hydrophobic PFAS. Preliminary plant studies in soil show an increased PFOA bioconcentration when positively charged UMNs are present. Molecular dynamics simulations focusing on interactions between the different functional groups on the silica surface and PFAS molecules showed the importance of the combination of hydrophobic and electrostatic interactions to drive PFAS uptake. The study highlights the potential of surface-modified UMNs to enhance the uptake of PFAS from the environmental matrix and promote phytoremediation.

Kim, H.B., M.F. Ehsan, A.N. Alshawabkeh and J.G. Kim.
Bioresource Technology 430:132563(2025)

Electrochemical activation was proposed as a sustainable method to enhance alum sludge adsorption performance by generating oxygen-containing functional groups on its surface. Cathodic-activated AlS (E-AlS) leads to the formation of hydroxyl and carboxyl groups, which serve as key active sites for Pb(II) adsorption through complexation mechanisms. E-AlS effectively removed both Pb(II) and As within 4 hrs, showcasing its dual functionality for cationic and anionic contaminants. While HCl- and KOH-activated AlS also achieved 100% Pb (II) removal, they caused substantial aluminum (Al) leaching, exceeding 1,000 mg/L, due to structural instability. In contrast, E-AlS minimized Al leaching, preserved structural integrity, and exhibited a 6.5-fold higher Pb (II) adsorption capacity than raw AlS. X-ray photoelectron spectroscopy and machine learning validated the enhanced adsorption performance of E-AlS. Findings highlight electrochemical activation as cost-effective and environmentally friendly remediation.

Field, J.A. SERDP Project ER19-1069, 3 pp, 2025

The goal of this project was to demonstrate the complete biodegradation of insensitive munition compounds (IMCs) to benign mineral products, using 3-nitro-1,2,4-triazol-5-one (NTO), by developing multiple microbial cultures that catalyzed the degradation of IMCs. It offers strategies to promote the complete mineralization of IMCs, thereby minimizing the accumulation of toxic aromatic amines and related byproducts. A highly enriched NTO-respiring culture was discovered that can transform NTO into 3-amino-1,2,4-triazol-5-one (ATO) via a mechanism similar to the halorespiration of chlorinated solvents. The study further demonstrated that a sulfate-reducing enrichment culture can transform nitroguanidine (NQ) into nitrosoguanidine (NsoQ) and describes a microbial community associated with the anaerobic biotransformation of NQ. Anaerobic conversion was a prerequisite for complete NTO mineralization. By providing shifting redox conditions in a sequential anaerobic–aerobic treatment system, full NTO and ATO biomineralization to safe products was attained in batch and continuous-flow bioreactors. Another important finding is the involvement of both biotic and abiotic reactions in IMC biodegradation. A link was discovered between the microbial respiration of natural organic matter by quinone-respiring bacteria and the chemical reduction of a broad array of nitroaromatics, which can play an important role in determining the environmental fate of IMCs and can facilitate bioremediation efforts. The project showed that NsoQ is further transformed via abiotic reactions. The study also showed that tailored microbial cultures can be designed to mineralize IMCs in specific waste streams.
Fact Sheet: https://sepub-prod-0001-124733793621-us-gov-west-1.s3.us-gov-west-1.amazonaws.com/s3fs-public/2025-04/ER19-1069%20Fact%20Sheet.pdf?VersionId=_Z8nT42t1zb.vFMCI63z.Cg9O3jqK_0t
Final Report: https://sepub-prod-0001-124733793621-us-gov-west-1.s3.us-gov-west-1.amazonaws.com/s3fs-public/2024-07/ER19-1069%20Final%20Report.pdf?VersionId=3MbIG5Kk6dwcH1LrmlU162oN2GhAIJGE
Executive Summary: https://sepub-prod-0001-124733793621-us-gov-west-1.s3.us-gov-west-1.amazonaws.com/s3fs-public/2024-01/ER19-1069%20Executive%20Summary.pdf?VersionId=xyuWT9.d_NMXmzlxmhY7OGzzbi8AbInC

Li, S., J.A. Goodrich, E. Costello, D.I. Walker, C. Cardenas-Iniguez, J.C. Chen, T.L. Alderete, D. Valvi, S. Rock, S.P. Eckel, R. McConnell, F.D. Gilliland, J. Wilson, B. MacDonald, D.V. Conti, A.L. Smith, D.L. McCurry, A.E. Childress, A.M.-A. Simpson, L. Golden-Mason, and L. Chatzi. ǀ Environmental Research 264(Part 1):120370(2025)

Two cohorts in Southern California were leveraged with 8 PFAS concentrations measured in plasma. PFAS water testing data was obtained from the Third Unregulated Contaminant Monitoring Rule and state monitoring data, census tract-level information on food access using the Food Access Research Atlas, Superfund site locations on the NPL, and data on facilities known to release PFAS. The data were spatially linked to the participants' home addresses. In the first cohort, PFOS, PFOA, and PFHxS detections in drinking water were associated with 1.54 ng/mL (95% CI: 0.77, 2.32), 0.47 ng/mL (0.25, 0.68), and 1.16 ng/mL (0.62, 1.71) increase in plasma PFOS, PFOA, and PFHxS. The presence of Superfund sites was associated with higher plasma concentrations of PFOS, PFHxS, PFPeS, and PFHpS (betas [95% CIs]: 0.96 [0.21, 1.71], 0.9 [0.22, 1.58], 0.04 [0.02, 0.06] and 0.05 [0.02, 0.09], respectively). Each additional PFAS-polluting facility present in the neighborhood was associated with a 0.9 ng/mL (0.03, 0.15) increase in the concentration of PFOS. In the other cohort, the presence of Superfund sites was associated with higher plasma PFDA, PFHpS, PFOS (betas [95% CIs]: 0.03 [0.01, 0.06], 0.05 [0.01, 0.09], and 1.96 [0.31, 3.62]). Neighborhood low access to food was associated with a 2.51 ng/mL (0.7, 4.31) increase in plasma PFOS, 0.6 ng/mL (0.16, 1.06) increase in plasma PFOA and 0.06 (0.02, 0.1) increase in plasma PFHpS.

Butzlaff, A.H., B. Mezgebe, A. Collins, Z.-W. Lin, D. Lassalle-Vega, I.M. Harmody, O. Coronell, F.A. Leibfarth, W.R. Dichtel, M. Nadagouda, and M. Ateia.
Chemical Engineering Journal 511:161983(2025)

A study investigated the performance of three cyclodextrin-based polymers, a hydrogel, and a polymer-metal oxide hybrid against traditional granular activated carbon (GAC) and ion exchange (IX) resins. This study comprehensively evaluated emerging PFAS-selective materials across five distinct and challenging waste matrices, providing critical insights into their practical applicability. The PFAS-selective adsorbents exhibited faster adsorption kinetics and higher PFAS removal efficiencies in these complex matrices. The key to enhanced performance was designing the interplay of multiple factors, including electrostatic attraction and hydrophobic capture, as well as pore configuration or fluorophilic interactions, that lead to higher affinity for PFAS removal. Mechanistic desorption studies demonstrated that a solvent-salt combination significantly improved PFAS recovery rates, up to 225-fold higher than single-component regenerants. Findings suggest a pathway toward sustainable PFAS remediation, minimizing environmental impact by enabling adsorbent reuse. The study highlights the high potential of the novel adsorbents to enhance PFAS management in diverse aqueous environments. Future work should focus on refining adsorbent formulations and regeneration protocols to maximize their practical application and adaptability to regulatory frameworks and environmental contexts.

Huizenga, J.M., L. Semprini, and M. Garcia-Jaramillo.
Environmental Science & Technology 59(15):7561-7573(2025)

Treatment strategies for PAHs can lead to the formation of PAH-transformation products (PAH-TPs) that are unregulated and understudied in environmental monitoring and remediation despite having the potential for adverse ecological and human health effects. Suspect and nontarget screening approaches were utilized to identify PAH-TPs produced by Rhodococcus rhodochrous ATCC 21198 using liquid chromatography-high resolution mass spectrometry. Open-source tools were used to predict biotransformation products, predict potential PAH-TP structures from mass spectra, and estimate health hazards of potential PAH-TPs. The workflow developed allowed for the tentative identification of 16 PAH-TPs, seven of which were not previously detected by targeted analysis. Several new potential transformation pathways for the bacterial pure culture were suggested by the PAH-TPs, including carboxylation, sulfonation and up to three hydroxylation reactions. A computational toxicity assessment indicated that the PAH-TPs shared many hazard characteristics with their parent compounds, including genotoxicity and endocrine disruption, highlighting the importance of considering PAH-TPs in future PAH studies.

Waltermire, K., D. Gwisdalla, and M. Mahoney. EPA/600/R-25/137, 51 pp, 2025

This guide provides key information to help environmental cleanup professionals and other stakeholders understand how different phytotechnologies work and assess their applicability to remediate or control contaminants in various media. It also includes case studies and practical guidance for planning a phytotechnology application, such as effective plant-contaminant pairings, resilience considerations, operation and maintenance, and long-term monitoring. https://cfpub.epa.gov/si/si_public_record_Report.cfm?dirEntryId=366104&Lab=CESER

NAVFAC Fact Sheet, 5 pp, 2025

Understanding the nature and strength of PFAS leaching from soil to groundwater is critical for effective site management. Soil can retain PFAS, potentially resulting in a long-term source of PFAS in groundwater. The unique physicochemical properties of PFAS result in complex fate and transport behavior in the vadose zone, and in some cases may require specialized evaluations to determine how soil-to-groundwater leaching fits into a particular conceptual site model. This fact sheet explains how different PFAS migrate through the vadose zone, how to estimate groundwater recharge rates, and how to estimate PFAS concentrations in porewater. https://exwc.navfac.navy.mil/Portals/88/Documents/EXWC/Restoration/er_pdfs/p/PFAS%20Leaching%20from%20Soil%20March%202025.pdf?ver=mKcMLBiTezrmZWXtoe2Tlg%3D%3D

Smith, K.P., F.D. Day-Lewis, J.P. Heneghan, and N.P. Qafoku. PNNL-37298, 20 pp, 2024

RemPlex collaborated with the United Kingdom's Nuclear Decommissioning Authority to host a two-day workshop focusing on the challenge of vertical delineation of contamination in aquifers underlying and/or impacted by complex sites. The workshop brought together an international group of researchers, site operators, government agency staff, practitioners, and regulators to identify challenges and potential solutions to enable the design and optimization of targeted remedies and groundwater monitoring programs.
Final Report: https://www.pnnl.gov/sites/default/files/media/file/RemPlex_NDA%20October%202024%20Workshop%20Report%20%28PNNL-37298%29.pdf
Presentations: https://www.pnnl.gov/sites/default/files/media/file/RemPlex-NDA_Workshop_Presentations-Combined_10-10-2024.pdf

Slater, L., A. Flores-Orozco, and H. Emerson. Pacific Northwest National Laboratory RemPlex seminar, 80 slides, June 2025

This seminar explores the application of geophysical techniques for understanding, characterizing and monitoring complex remediation sites, with a special focus on the Spectral Induced Polarization (SIP) method. SIP is an emerging geophysical technology that can offer unique non-invasive information on both the physical and geochemical conditions of the subsurface, particularly in environments where contamination and heterogeneous geological conditions pose significant challenges to collecting data at relevant spatial and temporal scales. The presenters highlight recent advancements in both lab-scale analysis of SIP signals and their field-scale applications, including several case studies. This session provides environmental scientists, engineers, and practitioners with an understanding of how SIP might be used to enhance the understanding of subsurface processes and improve remediation outcomes at complex sites. https://www.pnnl.gov/sites/default/files/media/file/RemPlex_Seminar_SubSurface-Sensing-SIP_presentationslides_3June2025.pdf

Morway, E.D., Alden M. Provost, Christian D. Langevin, Joseph D. Hughes, Martijn J. Russcher, Chieh-Ying Chen, Yu-Feng F. Lin. ǀ Groundwater 63(3):409-421(2025)

Heat transport in the subsurface is an important aspect of research related to the effects of a warming climate on ecological services, the development of geothermal resources for energy banking schemes, and the effects of temperature on other aspects of groundwater quality, such as nutrient cycling. Historically, simulating heat transport using MODFLOW and related codes was performed by scaling the input parameters of a solute-transport model to emulate heat transport. However, the approach required additional pre- and post-processing of input and output and could not account for variations in effective thermal storage and transport properties during transient, unsaturated flow. True heat-transport capabilities in the context of MODFLOW were first introduced in USG-Transport. A new groundwater energy-transport (GWE) model type has been added to MODFLOW 6 that supports the simulation of heat transport on structured or unstructured grids as well as within and between features of advanced packages that represent streams, lakes, multi-aquifer wells, and the unsaturated zone. GWE is integrated within MODFLOW 6 and is accessible through the FloPy Python package and the MODFLOW 6 application programming interface. An example simulation demonstrates conduction between grid cells through both the water and the solid aquifer material, including thermal bleeding from saturated overburden cells into a groundwater flow field.