PFAS remediation framework

1. PFAS Monitored Retention Framework and Integration of CAC

Adamson, D., Newell, C., Kulkarni, P., Stroo, H., Groundwater Monitoring & Remediation 45, no. 3 (2025) pages 37–49 link

The abstract introduces PFAS Monitored Retention (PMR) as an evolution of traditional Monitored Natural Attenuation (MNA), tailored to address the persistent nature of PFAS in groundwater. PMR leverages retention mechanisms like sorption and matrix diffusion to manage PFAS mobility and offers a cost-effective, scientifically sound solution.

2. Enhanced attenuation (EA) to manage PFAS plumes in groundwater

Newell, C. J., Javed, H., Li, Y., Johnson, N. W., Richardson, S. D., Connor, J. A. and Adamson, D. T. (2022), Remediation Journal, 4 August. link

This article identifies and compares 8 enhanced attenuation approaches for PFAS plumes for sites on their applicability, potential increases in PFAS mass retention, potential disadvantages, alternate designs, development status, and likelihood of large-scale adoption.

3. Monitored natural attenuation to manage PFAS impacts to groundwater: Potential guidelines

Newell, C. J., Adamson, D. T., Kulkarni, P. R., Nzeribe, B. N., Connor, J. A., Popovic, J. and Stroo, H. F. (2021), Remediation Journal, 17 August. link

This article discusses practical guidelines based on a three-tiered lines of evidence (LOE) approach for evaluating monitored natural attenuation (MNA) of PFAS.

Proof of concept

1. Factors affecting the adsorption of per- and polyfluoroalkyl substances (PFAS) by colloidal activated carbon

Hakimabadi, S. G., Taylor, A. and Pham, A. L.-T. (2023) Water Research, 15 August. link

This article identifies key factors influencing PFAS adsorption onto CAC, addressing topics like co-contaminant influences on adsorption effectiveness

2. A systematic study of the competitive sorption of per- and polyfluoroalkyl substances (PFAS) on colloidal activated carbon

Niarchos, G., Georgii, L., Ahrens, L., Berggren Kleja, D. and Fagerlund, F. (2023), Ecotoxicology and Environmental Safety, 1 October. link

This article explores how PFAS compounds of varying chain lengths and functional groups compete for sorption sites on CAC, impacting overall remediation effectiveness

3. Per- and polyfluoroalkyl substance (PFAS) retention by colloidal activated carbon: A dynamic column experiment

Niarchos, G., Ahrens, L., Berggren Kleja, D. and Fagerlund, F. (2022), Environmental Pollution, 1 August. link

This article demonstrates that colloidal activated carbon (CAC) significantly enhances PFAS retention in soil columns, with retention rates up to 99.7% higher than untreated controls.

Modeling

1. Tool and database for estimating potential longevity of colloidal activated carbon barriers for PFAS remediation

Newell C. J., Smith W. B., Kearney K., Clay S., Javed H., Carey G. R., Richardson S. D., Werth C. J. (2025) ‘, Remediation Journal, 14 April. link

This article introduces a predictive tool and database to estimate the lifespan of CAC barriers, aiding in long-term planning for PFAS remediation efforts.

2. Modeling the influence of coastal site characteristics on PFAS in situ remediation

Carey, G. R., Danko, A., Pham, A. L.-T., Soderberg, K., Hoagland, B. and Sleep, B. (2024) ‘, Groundwater, 15 February. link

This article utilizes modeling to assess how coastal factors, such as tidal influences and ionic strength, affect the performance of CAC barriers in PFAS remediation.

3. Analysis of Colloidal Activated Carbon Alternatives for In Situ Remediation of a Large PFAS Plume and Source Area

Carey, G. R., R. H. Anderson, P. Van Geel, et al. 2023. Remediation Journal 34, no. 1: e21772. link

This article evaluates CAC adsorption capacity, providing insights into optimal application strategies for large-scale PFAS plumes.

4. Evaluating the longevity of a PFAS in situ colloidal activated carbon remedy

Carey, G. R., McGregor, R., Pham, A. L., Sleep, B., and Hakimabadi S. G. (2021), Remediation Journal. link

This article discusses the three-dimensional reactive transport model (ISR-MT3DMS) used to indicate that the CAC remedy implemented at the site is likely to be effective for PFOS remediation for decades.

Field Applications

1. In‐situ application of colloidal activated carbon for PFAS‐contaminated soil and groundwater: A Swedish case study

Niarchos, G., Ahrens, L., Kleja, D. B., Leonard, G., Forde, J., Bergman, J., Ribeli, E., Schütz, M., & Fagerlund, F. (2023).Remediation, 33, 101–110. link

This article presents a pilot-scale study demonstrating the effectiveness of CAC in stabilizing PFAS in contaminated soils and preventing groundwater leaching.

2. Longevity of colloidal activated carbon for in situ PFAS remediation at AFFF‐contaminated airport sites

Carey, G. R., Hakimabadi, S. G., Singh, M., McGregor, R., Woodfield, C., Van Geel, P. J., & Pham, A.‐T. (2022). ‘. Remediation, 1–21.  link

Case studies of 17 PFAS field sites showing successful PlumeStop performance results for up to six years and counting. In-Situ Remediation Model (ISR-MT3DMS) indicates PlumeStop longevity that may occur at a wide range of AFFF-impacted military and airport sites.

3. The effect of heterogeneity on the distribution and treatment of PFAS in a complex geologic environment

McGregor, R. and Benevenuto, L. (2021), Frontiers in Environmental Chemistry, 20 September. link

This case study article reviews the effect of heterogeneity on the distribution of colloidal activated carbon (CAC) and subsequent treatment of PFAS at a site with a multiple aquifer system. PFAS in groundwater were treated effectively to below their respective reporting limits for the duration of the 1-year test in both the silty sand and sand aquifers.

4. The in situ treatment of TCE and PFAS in groundwater within a silty sand aquifer

McGregor, R. and Zhao, Y. (2021), Remediation Journal, 31(2), pp. 7–17. link

This article is a case study of in-situ treatment of TCE and PFAS in groundwater at an industrial site within a silty sand aquifer. Sampling of the groundwater over a 24-month period indicated that the detected PFAS were treated to either their detection, or below the analytical detection limit over the monitoring period.

5. Six pilot-scale studies evaluating the in situ treatment of PFAS in groundwater

McGregor, R. (2020), Remediation, 30(3), pp. 39–50. link ​

This article reviews six pilot-scale in-situ field studies of an unconfined sand aquifer impacted by both petroleum hydrocarbons and PFAS to determine if a variety of reagents could be used to attenuate the dissolved PFAS.

6. In situ treatment of PFAS-impacted groundwater using colloidal activated carbon

McGregor, R. (2018), Remediation Journal, 1 January. link

This article documents the first ever in situ PlumeStop application to treat PFAS, a single application of PlumeStop resulted in a significant reduction of contaminant concentrations to below standards for 18+ months since the injection. Modeling indicates that the PlumeStop application event should keep the PFAS contained within the source area for decades.

Technology Comparison

1. Sustainability Assessment of In Situ and Ex Situ Remediation fo PFAS-Contaminated Groundwater

Thoreson, K.A., Laitinen, J., Leonard, G., (2025), Remediation, Volume 35, Issue 4.  link

This article highlights the potential environmental, economic, and societal advantages of using the in situ CAC approach to remediate PFAS-contaminated groundwater

2. A Cost Comparison of Pump-and-Treat and In Situ Colloidal Activated Carbon for PFAS Plume Management

Birnstingl, J. G. A., Wilson, J., (2024). ‘. Remediation, 35, e70005. link

This research article discloses the high cost the US DoD is paying to contain a PFAS plume at an existing DoD installation employing a typical pump and treat approach. Further, the paper compares the costs of operating the current remediation system with the costs of installing and operating an in situ CAC filtration system. For the subject site, in situ CAC filtration was shown to be about 1/3 the cost of pump and treat systems over a 30-year period ($7.2M vs $19M)

3. Pandora’s PFAS box: Life cycle exposure considerations of treatment options for PFAS in groundwater

Hall, L. C., Wilson, J. T., & Birnstingl, J. G. A. (2024). ‘. Remediation, 34, e21775. link

This article examines the life cycle exposure risks associated with various PFAS treatment methods, emphasizing the need for holistic remediation approaches.

4. Available and emerging liquid treatment technologies for PFASs

DiGuiseppi, W. H., Newell, C. J., Carey, G., Kulkarni, P. R., Xia, Z., Stults, J., Maher, T. L., Houtz, E. F., Mora, R., Wice, R., Tomiczek, P. W., Richardson, S. D., Xiong, J., Hale, J., Hnatko, J. P., McGregor, R., McDonough, J. T., Oka, A., Thomas, R., Fenstermacher, J., and Hatton, J. (2024), Remediation Journal, 21 May. link

This article provides a comprehensive review of current and emerging treatment technologies for PFAS in water, highlighting their applicability and limitations.

5. ​Distribution of colloidal and powdered activated carbon for the in situ treatment of groundwater

McGregor, R. (2020), Journal of Water Resource and Protection, 12(12), pp. 1001–1018. link

This article compares the distribution patterns of colloidal versus powdered activated carbon in groundwater, informing best practices for in situ PFAS treatment.

Soil Treatment

1. Stabilization of per- and polyfluoroalkyl substances (PFASs) with colloidal activated carbon (PlumeStop®) as a function of soil clay and organic matter content

Sorengard, M., Kleja, D. B., Ahrens L., (2019) ‘, Journal of Environmental Management, Volume 249, 109345. link

This article investigates how soil properties, specifically clay and organic matter content, influence the effectiveness of PlumeStop® in stabilizing PFAS.

2. Stabilisation of PFAS in soils: Long-term effectiveness of carbon-based soil amendments

Navarro, D., Fagerlund, F., McGregor, R., and Ahrens, L. (2023) ‘, Environmental Pollution, 323, 121249. link

This article assesses the durability of carbon-based amendments in PFAS-contaminated soils, confirming their long- term stabilization potential.