Per- and Polyfluoroalkyl Substances in Sediments from an Urban Riparian Floodplain: Distribution, Partitioning, and Fate

Environmental Science & Technology · 2026-05-18

Floodplain and wetland sediments serve as critical interfaces between surface water and groundwater, where per- and polyfluoroalkyl substances (PFAS) in urban waterways can infiltrate, accumulate, and partition across solid, liquid, and air-water interfaces. We measured the spatial and vertical distributions of 40 PFAS in floodplain sediments in a Southern California urban watershed. We detected perfluorooctanesulfonic acid (PFOS) most frequently and at the highest concentrations. We performed desorption and sequential batch adsorption-desorption experiments to estimate PFOS in situ pore-water concentrations and to quantify hysteretic behavior during repeated cycles of adsorption and desorption. Estimated in situ PFOS pore-water concentrations in vadose zone sediments were more than twice (78 ng/L) those in recently measured surface water (<30 ng/L), which may reflect seasonal fluctuations in water-content-dependent partitioning and long-term trends in surface water. Our new method of employing mass-labeled PFOS in batch experiments presents direct comparisons of the adsorption of field-derived PFOS to that of PFOS introduced at discrete steps in the laboratory. Our results suggest two mechanisms governing hysteresis in PFOS solid-phase partitioning across distinct time scales: (1) rapid mass exchange at sediment surfaces influenced by the historical maximum aqueous concentration, and (2) rate-limited diffusion of PFOS in organic-rich sediments occurring over long time scales in the field but not in most laboratory batch experiments.

Determination of household wastewater PFAS composition and concentrations via neighborhood sampling

Journal of Hazardous Materials · 2025-09-10 · 5 citations

AEESP Spotlight: Early 2025

Environmental Engineering Science · 2025-02-01

Determination of household wastewater PFAS composition and concentrations via sub-sewershed analysis

ChemRxiv · 2025-01-21

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in wastewater, challenging water reuse efforts. The PFAS in wastewater are contributed by industrial, commercial, and residential sewerage users. To date, very little is known about the composition and concentration of PFAS discharged by households. We addressed this important knowledge gap by analyzing 24-hour composite wastewater samples obtained for seven consecutive days from three residential sub-sewersheds upstream of wastewater treatment plants. Tap water collected from parks at each sub-sewershed was also analyzed. Although tap water contained some PFAS, we found more analytes and higher concentrations in the residential wastewater samples, suggesting PFAS was introduced at households. The daily ∑PFAS was 10.43 – 49.14 ng/L across the locations. There were no significant (p &gt; 0.05) differences in PFAS concentrations measured on weekdays compared to weekends. PFHxA, PFOA, PFHxS, and PFOS were present in all the samples we obtained, indicating their consistency in consumer products and, thus, residential wastewater. PFOA and PFOS accounted for 12 – 61% of the daily ∑PFAS. We estimated individual PFAS contribution as 2.27 – 10.71 µg/capita/day, with more affluent neighborhoods discharging more PFAS. This is the first study to estimate per capita PFAS using wastewater from upstream household discharge points.

Determination of household wastewater PFAS composition and concentrations via sub-sewershed analysis

ChemRxiv · 2025-01-21

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in wastewater, challenging water reuse efforts. The PFAS in wastewater are contributed by industrial, commercial, and residential sewerage users. To date, very little is known about the composition and concentration of PFAS discharged by households. We addressed this important knowledge gap by analyzing 24-hour composite wastewater samples obtained for seven consecutive days from three residential sub-sewersheds upstream of wastewater treatment plants. Tap water collected from parks at each sub-sewershed was also analyzed. Although tap water contained some PFAS, we found more analytes and higher concentrations in the residential wastewater samples, suggesting PFAS was introduced at households. The daily ∑PFAS was 10.43 – 49.14 ng/L across the locations. There were no significant (p &gt; 0.05) differences in PFAS concentrations measured on weekdays compared to weekends. PFHxA, PFOA, PFHxS, and PFOS were present in all the samples we obtained, indicating their consistency in consumer products and, thus, residential wastewater. PFOA and PFOS accounted for 12 – 61% of the daily ∑PFAS. We estimated individual PFAS contribution as 2.27 – 10.71 µg/capita/day, with more affluent neighborhoods discharging more PFAS. This is the first study to estimate per capita PFAS using wastewater from upstream household discharge points.

Elimination of microplastics, PFAS, and PPCPs from biosolids via pyrolysis to produce biochar: Feasibility and techno-economic analysis

The Science of The Total Environment · 2024-07-14 · 38 citations

Biosolids from municipal wastewater treatment contain many contaminants of emerging concern, including microplastics (MPs), per- and polyfluoroalkyl substances (PFAS), pharmaceuticals and chemicals from personal care products (PPCPs). Many of these contaminants have very slow biotic or abiotic degradation rates and have been shown to have human and ecological health impacts. Application of biosolids to agriculture, a common disposal method, can result in extended environmental contamination. An approach for eliminating the contaminants is pyrolysis, which can also generate biochar, enhancing carbon sequestration as a side-benefit. We pyrolyzed biosolid samples from an operating facility at various temperatures from 400 to 700 °C with a 2-hour residence time. We then evaluated contaminant removal, which in many cases was 100 %, with only a few residuals. No trace of PFAS was detectable even at 400 °C. Overall mass removal of PPCPs, including PFAS, was over 99.9 %. MP removal via pyrolysis ranged from 91 to 97 %. The biochar contains significant amounts of Fe and P, which make it a useful fertilizer amendment. The techno-economic analysis indicates that pyrolysis may generate significant cost savings, and revenue from the sale of biochar, sufficient to more than cover the investment and operating costs of the dryer and pyrolysis unit.

Adsorption of PFAS onto secondary microplastics: A mechanistic study

Journal of Hazardous Materials · 2024-03-31 · 95 citations

Microplastics (MPs) are abundant in aquatic systems. The ecological risks of MPs may arise from their physical features, chemical properties, and/or their ability to concentrate and transport other contaminants, such as per- and polyfluoroalkyl substances (PFAS). PFAS have been extracted from MPs found in natural waters. Still, there needs to be a mechanistic investigation of the effect of PFAS chemistry and water physicochemical properties on how PFAS partition onto secondary MPs. Here, we studied the influence of pH, natural organic matter (NOM), ionic strength, and temperature on the adsorption of PFAS on MPs generated from PET water bottles. The adsorption of PFAS to the MPs was thermodynamically spontaneous at 25 °C, based on Gibb’s free energy (Δ G = −16 to −23 kJ/mol), primarily due to increased entropy after adsorption. Adsorption reached equilibrium within 7–9 h. Hence, PFAS will partition to the surface of secondary PET MPs within hours in fresh and saline waters. Natural organic matter decreased the capacity of secondary PET MPs for PFAS through electrosteric repulsion, while higher ionic strength favored PFAS adsorption by decreasing electrostatic repulsion. Increased pH increased electrostatic repulsion, which negated PFAS adsorption. The study provides fundamental information for developing models to predict interactions between secondary MPs and PFAS. • PET microplastics (MPs) were produced from PET water bottles. • The adsorption of PFAS to the MPs was thermodynamically spontaneous at 25 °C. • Δ S and change in the intensity of the IR peak at 1089 cm −1 significantly correlated. • The q e of MPs for PFAS increased as ionic strength or temperature increased. • The q e of MPs for PFAS decreased as pH or NOM concentration increased.

Mechanistic Insight into the Synergistic Removal of Metallic and Nonmetallic Cocontaminants in Water by Iron Nanoparticles

ACS ES&T Water · 2024-07-02 · 5 citations

Industrial wastewaters with high concentrations of multiple classes of contaminants are challenging to treat and may require multistage treatment processes. This study aimed to develop and optimize a simple framework to simultaneously remove metals and nonmetals that commonly coexist in industrial wastewater. Based on a hypothesis that zerovalent iron (Fe0) will synergistically remove metals (with a more positive standard reduction potential than Fe2+/Fe0; E° = −0.44 V) and anions via interconnected chemical processes, we studied the simultaneous removal of copper (Cu2+) and phosphorus (P) using pristine and sulfidized nanoscale zerovalent iron (NZVI and SNZVI, respectively). The removal capacity of NZVI increased from 0.303 mg-Cu/m2 and 1.650 mg-P/m2 in single-contaminant systems to 1.136 mg-Cu/m2 and 1.673 mg-P/m2 in multicontaminant systems. We established that Fe2+, a major product of Fe0 and Cu2+ reactions, is a reactant in P precipitation that creates feedback. Sulfidation of NZVI (S/Fe = 0.28) enhanced the removal capacities to 3.140 mg-Cu/m2 and 3.295 mg-P/m2 in single-contaminant systems and 4.831 mg-Cu/m2 and 4.803 mg-P/m2 in multicontaminant systems because additional Fe2+ was produced by reactions between Cu2+ and FeS. Finally, we introduced a framework for using artificial neural networks (ANNs) to optimize the system.

AEESP Spotlight: Early 2024

Environmental Engineering Science · 2024-01-24

Enhanced electrochemical treatment of humic acids and metal ions in leachate concentrate: Experimental and molecular mechanism investigations

Journal of Hazardous Materials · 2023-10-12 · 13 citations