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Yu L, Liu X, Hua Z, Chu K. Intense Turbulent Bursts Promote the Release of Perfluoroalkyl Acids from Sediments at High Flow Velocity. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 38889003 DOI: 10.1021/acs.est.4c03885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Despite frequent detection of high levels of perfluoroalkyl acids (PFAAs) in sediments, research on the environmental fate of PFAAs in sediments, particularly under hydrodynamic conditions, is rather limited, challenging effective management of PFAA loadings. Therefore, this study investigated the release and transport of 15 PFAAs in sediments under environmentally relevant flow velocities using recirculating flumes and revealed the underlying release mechanisms by identifying related momentum transfer. An increased velocity enhanced the release magnitude of total PFAAs by a factor of 3.09. The release capacity of short-chain PFAAs was notably higher than that of long-chain PFAAs, and this pattern was further amplified by flow velocity. Pore-water drainage was the major pathway for PFAA release, with the release amount predominantly determined by flow velocity-induced release intensity and depth, as well as affected by the perfluorocarbon chain length and sediment size. The weak anion exchanger-diffusion gradients in the thin-film technique confirmed that the release depth of PFAAs increased with flow velocity. Quadrant analysis revealed that the rise in the frequency and intensity of turbulent bursts driven by sweeps and ejections at high flow velocity was the underlying cause of the increased release magnitude and depth of PFAAs.
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Affiliation(s)
- Liang Yu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
- Yangtze Institute of Conservation and Development, Hohai University, Nanjing 210098, China
| | - Xiaodong Liu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
- Yangtze Institute of Conservation and Development, Hohai University, Nanjing 210098, China
| | - Zulin Hua
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
- Yangtze Institute of Conservation and Development, Hohai University, Nanjing 210098, China
| | - Kejian Chu
- Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake, Ministry of Education, College of Environment, Hohai University, Nanjing 210098, China
- Yangtze Institute of Conservation and Development, Hohai University, Nanjing 210098, China
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Stults JF, Schaefer CE, Fang Y, Devon J, Nguyen D, Real I, Hao S, Guelfo JL. Air-water interfacial collapse and rate-limited solid desorption control Perfluoroalkyl acid leaching from the vadose zone. JOURNAL OF CONTAMINANT HYDROLOGY 2024; 265:104382. [PMID: 38861839 DOI: 10.1016/j.jconhyd.2024.104382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 05/08/2024] [Accepted: 06/02/2024] [Indexed: 06/13/2024]
Abstract
Some Per- and polyfluoroalkyl substances (PFAS) are strongly retained in the vadose zone due to their sorption to both soils and air-water interfaces. While significant research has been dedicated to understanding equilibrium behavior for these multi-phase retention processes, leaching and desorption from aqueous film-forming foam (AFFF) impacted soils under field relevant conditions can exhibit significant deviations from equilibrium. Herein, laboratory column studies using field collected AFFF-impacted soils were employed to examine the leaching of perfluoroalkyl acids (PFAAs) under simulated rainfall conditions. The HYDRUS 1-D model was calibrated to estimate the unsaturated hydraulic properties of the soil in a layered system using multiple boundary condtions. Forward simulations of equilibrium PFAS partitioning using the HYDRUS model and simplified mass balance calculations showed good agreement with the net PFAS mass flux out of the column. However, neither were able to predict the PFAS concentrations in the leached porewater. To better understand the mechanisms controlling the leaching behavior, the HYDRUS 1-D two-site leaching model incorporating solid phase rate limitation and equilibrium air-water interfacial partitioning was employed. Three variations of the novel model incorporating different forms of equilibrium air-water interfacial partitioning were considered using built-in numerical inversion. Results of numerical inversion show that a combination of air-water interfacial collapse and rate-limited desorption from soils can better predict the unique leaching behavior exhibited by PFAAs in AFFF-impacted soils. A sensitivity analysis of the initial conditions and rate-limited desorption terms was conducted to assess the agreement of the model with measured data. The models demonstrated herein show that, under some circumstances, laboratory equilibrium partitioning data can provide a reasonable estimation of total mass leaching, but fail to account for the significant rate-limited, non-Fickian transport which affect PFAA leaching to groundwater in unsaturated soils.
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Affiliation(s)
- John F Stults
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States.
| | - Charles E Schaefer
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States; CDM Smith, 110 Fieldcrest Avenue, #8, 6th Floor, Edison, NJ 08837, United States
| | - Yida Fang
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States; Haley and Aldrich Inc., 3131 Elliott Ave #600, Seattle, WA 98121, United States
| | - Julie Devon
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States
| | - Dung Nguyen
- CDM Smith, 14432 SE Eastgate Way, Suite 100, Bellevue, WA 98007, United States
| | - Isreq Real
- Civil, Environmental, and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Shilai Hao
- Civil & Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Jennifer L Guelfo
- Civil, Environmental, and Construction Engineering, Texas Tech University, Lubbock, TX 79409, USA
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Shih CH, Kim J, Yang SH, Soker O, Strathmann TJ, Chu KH. Remediation of PFAS-impacted soils using magnetic activated carbon (MAC) and hydrothermal alkaline treatment (HALT). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168931. [PMID: 38042197 DOI: 10.1016/j.scitotenv.2023.168931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/24/2023] [Accepted: 11/25/2023] [Indexed: 12/04/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic pollutants that are bioaccumulative, toxic, and persistent. One long-term source for PFAS release is PFAS-contaminated soil. Addition of activated carbon (AC) to soil has shown the potential to immobilize PFAS and reduce PFAS bioavailability, but PFAS-loaded spent AC remaining in the treated soil could lead to remobilization. Here we report a novel approach to address this challenge. By applying magnetic activated carbon (MAC) to remediate PFAS-impacted soil, the PFAS-loaded MAC can be retrieved from the treated soil and sorbed PFAS in the spent MAC can be destroyed using hydrothermal alkaline treatment (HALT). Effective MAC recovery was observed when water/soil ratios (w/w) were either <0.07 or > 1. Soil organic content and pH affected PFAS adsorption by the MAC added to soil. After three months of incubation with MAC, high PFAS removals [PFOS (87.6 %), PFOA (83.8 %), and 6:2 FTSA (81.5 %)] were observed for acidic environmental sandy soils with low organic content. In contrast, PFAS removal by MAC was poor for garden soils with high organic matter content. MAC was also used to remediate aqueous film-forming foam (AFFF)-impacted and PFAS-contaminated aged soils with varying PFAS removal performance. HALT technology was able to destroy and defluorinate PFAS adsorbed to the spent MAC. Additionally, the HALT-treated MAC retained its magnetic properties and PFOS sorption capacity, suggesting the potential reusability of HALT-treated MAC. Considering the low energy footprint of HALT compared to conventional PFAS thermal destruction techniques, the combination of MAC and HALT could be a promising treatment train for PFAS-contaminated soils.
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Affiliation(s)
- Chih-Hsuan Shih
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Jinha Kim
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Shih-Hung Yang
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Ori Soker
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Timothy J Strathmann
- Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA
| | - Kung-Hui Chu
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
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Wanzek TA, Field JA, Kostarelos K. Repeated Aqueous Film-Forming Foams Applications: Impacts on Polyfluoroalkyl Substances Retention in Saturated Soil. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1659-1668. [PMID: 38198694 DOI: 10.1021/acs.est.3c04595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Historical practices at firefighter-training areas involved repeated aqueous film-forming foams (AFFFs) applications, resulting in source zones characterized by high concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFAS). Repeated applications of AFFF composed of 14 anionic and 23 zwitterionic perfluoroalkyl substances (PFAS) were conducted on a single one-dimensional saturated soil column to quantify PFAS retention. An electrofluorination-based (3M) Milspec AFFF, which was above the mixture's critical micelle concentration (CMC), was at application strength (3%, v/v). Retention and retardation of PFAS mass increased with each successive AFFF addition, although the PFAS concentration profiles for subsequent applications differed from the initial. Greater degree of mass retention and retardation correlated with longer PFAS carbon-fluorine chain length and charged-headgroup type and as a function of AFFF application number. Anionic PFAS were increasingly retained with each subsequent AFFF application, while zwitterionic PFAS exhibited an alternating pattern of sorption and desorption. Surfactant-surfactant adsorption and competition during repeat AFFF applications that are at concentrations above the CMC resulted in adsorbed PFAS from the first application, changing the nature of the soil surface with preferential sorption of anionic PFAS and release of zwitterionic PFAS due to competitive elution. Applying a polyparameter quantitative structure-property relationship developed to describe sorption of AFFF-derived PFAS to uncontaminated, saturated soil was attempted for our experimental conditions. The model had been derived for data where AFFF is below the apparent CMC and our experimental conditions that included the presence of mixed micelles (aggregates consisting of different kinds of surfactants that exhibit characteristics properties different from micelles composed of a single surfactant) resulted in overall PFAS mass retained by an average of 27.3% ± 2.7% (standard error) above the predicted values. The correlation was significantly improved by adding a "micelle parameter" to account for cases where the applied AFFF was above the apparent CMC. Our results highlight the importance of interactions between the AFFF components that can only be investigated by employing complex PFAS mixtures at concentrations present in actual AFFF at application strength, which are above their apparent CMC. In firefighter-training areas (AFFF source zones), competitive desorption of PFAS may result in downgradient PFAS retention when desorbed PFAS become resorbed to uncontaminated soil.
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Affiliation(s)
- Thomas A Wanzek
- Department of Crop and Soil Science, Oregon State University, Corvallis, Oregon 97331, United States
| | - Jennifer A Field
- Department Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon 97331, United States
| | - Konstantinos Kostarelos
- UH Energy Technology Innovation Center, University of Houston, Houston, Texas 77204, United States
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Huang YR, Liu SS, Zi JX, Cheng SM, Li J, Ying GG, Chen CE. In Situ Insight into the Availability and Desorption Kinetics of Per- and Polyfluoroalkyl Substances in Soils with Diffusive Gradients in Thin Films. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7809-7817. [PMID: 37155686 DOI: 10.1021/acs.est.2c09348] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The physicochemical exchange dynamics between the solid and solution phases of per- and polyfluoroalkyl substances (PFAS) in soils needs to be better understood. This study employed an in situ tool, diffusive gradients in thin films (DGT), to understand the distribution and exchange kinetics of five typical PFAS in four soils. Results show a nonlinear relationship between the PFAS masses in DGT and time, implying that PFAS were partially supplied by the solid phase in all of the soils. A dynamic model DGT-induced fluxes in soils/sediments (DIFS) was used to interpret the results and derive the distribution coefficients for the labile fraction (Kdl), response time (tc), and adsorption/desorption rates (k1 and k-1). The larger labile pool size (indicated by Kdl) for the longer chain PFAS implies their higher potential availability. The shorter chain PFAS tend to have a larger tc and relatively smaller k-1, implying that the release of these PFAS in soils might be kinetically limited but not for more hydrophobic compounds, such as perfluorooctanesulfonic acid (PFOS), although soil properties might play an important role. Kdl ultimately controls the PFAS availability in soils, while the PFAS release from soils might be kinetically constrained (which may also hold for biota uptake), particularly for more hydrophilic PFAS.
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Affiliation(s)
- Yue-Rui Huang
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Si-Si Liu
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Jin-Xin Zi
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Sheng-Ming Cheng
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Jun Li
- State Key Laboratory of Organic Geochemistry and Guangdong Province Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640, People's Republic of China
| | - Guang-Guo Ying
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
| | - Chang-Er Chen
- Environmental Research Institute/School of Environment, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou, Guangdong 510006, People's Republic of China
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