Activated persulfate (PS) is a common method used to generate sulfate radicals (SO4•-), a powerful oxidant capable of degrading a broad array of environmental contaminants. The reaction of SO4•- with non-target species (i.e., scavenging), contributes significantly to treatment inefficiency. Radical scavenging in this manner has been quantified for non-target chemical species in the aqueous phase but has never been quantified for solid phase media. Kinetic analysis and laboratory methods were developed to quantify the SO4•- scavenging rate constant (k≡S) for alumina, a naturally occurring mineral in soil and aquifer materials. SO4•- were generated in UV- and thermally-activated persulfate (UV-APS, T-APS) batch systems, and the loss of rhodamine B (RhB) served as an indicator of SO4•- activity. k≡S for alumina was 2.42×104 m-2 s-1 and 2.03×104 m-2 s-1 for UV-APS and T-APS oxidative treatment systems, respectively. At [alumina] >5 g L-1, the reaction of SO4•- with solid phase media increased over the aqueous phase reactions with RhB and aqueous scavengers. SO4•- scavenging by solid surfaces was orders of magnitude greater than reaction with the target compound and scavengers in the aqueous phase, underscoring the significant role of solid surfaces in scavenging SO4•-. This dataset is associated with the following publication: Rusevova Crincoli, K., C. Green, and S.G. Huling. Sulfate Radical Scavenging by Mineral Surfaces in Persulfate-Driven Oxidation Systems: Reaction Rate Constants and Implications. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, USA, 54(3): 1955-1962, (2020).

Reaction intermediates formed during the ultra-violet (UV) activation of hydrogen peroxide (H2O2) (UV-AHP) and persulfate (S2O82-) (UV-APS) include hydroxyl (•OH) and sulfate radicals (SO4•-), respectively. These radicals, used in oxidation treatment systems to degrade a broad spectrum of environmental contaminants, may also react with non-target chemical species (scavengers) that limit treatment efficiency. UV-AHP and UV-APS treatment systems were amended with solid phase alumina to assess scavenging by solid surfaces. The relative rates of reaction between the target compound, rhodamine B dye (RhB), and aqueous and solid phase scavengers was used to assess treatment performance. The overall rate of reaction and rate of radical scavenging was greater for •OH than SO4•-. Scavenging by dissolved constituents was dominated by the oxidant used (H2O2, S2O82-); and the rate of radical scavenging by alumina was greater than the rate of RhB oxidation in all cases. Treatment efficiency was lower in the UV-AHP than in the UV-APS treatment system and was attributed to greater aqueous and solid phase scavenging rates. The cost of commercially available H2O2 ($0.031 mol-1) and PS ($0.24 mol-1) was used in conjunction with the overall treatment efficiency to assess specific cost of treatment. The specific cost to treat the probe compound with UV-AHP was greater than UV-APS and was attributed to the much lower treatment efficiency with UV-AHP. The much-desired high reaction rate constants between •OH and environmental contaminants, relative to SO4•-, comes at the cost of greater combined scavenging rates, and consequently lower treatment efficiency. This dataset is associated with the following publication: Rusevova Crincoli, K., and S.G. Huling. Contrasting hydrogen peroxide- and persulfate-driven oxidation systems: Impact of radical scavenging on treatment efficiency and cost. Chemical Engineering Journal. Elsevier BV, AMSTERDAM, NETHERLANDS, 404: 1-6, (2021).

A two-phased bench-scale study was conducted to evaluate various sorbents for possible use as chemical stabilizing agents, along with cement solidification, for possible use in an in-situ solidification/stabilization (immobilization) treatment process for per- and polyfluoroalkyl (PFAS) contaminated soils. The first phase involved sorption experiments for six selected PFAS compounds diluted in a water solution, using five selected sorbents: granular activated carbon (GAC), activated carbon-clay blend, modified clay, biochar, iron (Fe)-amended biochar, and Ottawa sand as a control media. The second phase involved chemical stabilization treatment (via sorption), using the most effective sorbent identified in the first phase, followed by solidification of two soils from PFAS-contaminated sites. Physical solidification was achieved by adding cement as a binding agent. Results from the first phase (sorption experiments) indicated that GAC was slightly more successful than the other sorbents in sorption performance for a 3,000 µg/L solution containing a mixture of the six selected PFAS analytes (500 µg/L concentration each of shorter- and longer-chain alkyl acids), and was the only sorbent used in the second phase of this study. While the GAC, activated carbon-clay blend, and modified clay sorbents showed similar sorption performance for the longer chain analytes tested, both the activated carbon-clay blend and modified clay, exhibited slightly less sorptive capacity than GAC for the shorter-chain alkyl acids. Immobilization effectiveness was evaluated by soil leachability testing using Environmental Protection Agency (EPA) Method 1312, Synthetic Precipitation Leaching Procedure (SPLP) on the samples collected from two PFAS-contaminated sites. For the majority of the PFAS soil analytes, the addition of GAC sorbent (chemical stabilization) substantially reduced the leachability of PFAS compounds from the contaminated soil samples, and the addition of cement as a physical binding agent (solidification) further decreased leachability for a few of the PFAS compounds. Overall immobilization of PFAS analytes that were detectable in the leachate from two PFAS contaminated soils ranged from 87.1% to 99.9%. Therefore, it is reasonable to consider that the laboratory testing results presented here may have application to further pilot or limited field-scale studies within a broader suite of PFAS-contaminated site treatment options that are currently available for treating PFAS contaminated soils. This dataset is associated with the following publication: Barth, E., J. McKernan, D. Bless, and K. Dasu. Investigation of an immobilization process for PFAS contaminated soils. JOURNAL OF ENVIRONMENTAL MANAGEMENT. Elsevier Science Ltd, New York, NY, USA, 296: 113069, (2021).

Per- and polyfluoroalkyl substances (PFAS) chemicals are known to strongly sorb onto soils when being transported downward through the vadose zone. The degree to which this sorption occurs depends on the length of the specific PFAS molecular chain and the properties of the soil. The properties with greatest influence on the soils PFAS sorption potential are percent silt and clay, and organic matter content (Fabregat-Palau and others, 2021), which have small size fractions that provide more sorption sites. In addition to sorption, the estimated long-term mean-annual vertical transport velocity of any chemical in a soil zone can be calculated given the recharge rate and volumetric water content. The latter can be calculated given the recharge rate, percent clay, and saturated hydraulic conductivity (Clapp and Hornberger, 1978). Also, the retardation factor can be calculated if the bulk density and water content are known. Given these requirements, raster data of these soil properties, in addition to several others, were downloaded from the Polaris Soils database made available in 2019, and used in preliminary analyses to assess the vulnerability of shallow groundwater to perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) contamination at a national scale. The POLARIS data that were chosen in this study were percent silt, percent clay, percent sand, percent organic matter, saturated water content, saturated hydraulic conductivity, and bulk density. Rasters of these soil properties for each of the six depth layers included in the database were created for the contiguous United States (see compressed files percentclay.7z, percentsilt.7z, percentsand.7z, bulkdensity_bd.7z, saturatedhydraulicconductivity_ksat.7z, soilwatercontent_theta_s.7z, and soilorganicmatter_om.7z in Child Item section). The resulting rasters were used in analyses to create rasters of PFOS and PFOA sorption distribution coefficients (Kd values) as well as a classified soil raster based on the classic ternary diagram of the U.S. Department of Agriculture (Davis and Bennett, 1927). A 250-m resolution was chosen to be coincident with the 1-kilometer resolution grid of the USGS national hydrogeologic framework (Brassington and Younger, 2010). The POLARIS data are well represented at this, and even finer, resolutions (Chaney and others 2016). Future analyses to be conducted include combining these files with other existing rasters of mean-annual recharge and depth to the water table (Zell and Sanford, 2020) to develop a raster representing the vulnerability of shallow groundwater to PFOA and PFOS contamination for the contiguous United States.

chemical concentrations. This dataset is associated with the following publication: Falzone, S., C. Schaefer, E. Siegenthaler, K. Keating, D. Werkema, and L. Slater. Geophysical Signatures of Soil AFFF Contamination from Spectral Induced Polarization and Low Field Nuclear Magnetic Resonance Methods. JOURNAL OF CONTAMINANT HYDROLOGY. Elsevier Science Ltd, New York, NY, USA, 260: 104268, (2024).

chemical concentrations. This dataset is associated with the following publication: Falzone, S., C. Schaefer, E. Siegenthaler, K. Keating, D. Werkema, and L. Slater. Geophysical Signatures of Soil AFFF Contamination from Spectral Induced Polarization and Low Field Nuclear Magnetic Resonance Methods. JOURNAL OF CONTAMINANT HYDROLOGY. Elsevier Science Ltd, New York, NY, USA, 260: 104268, (2024).

The TROPESS CrIS-SNPP L2 Peroxyacetyl Nitrate for Reanalysis Stream, Summary Product contains the vertical distribution of the retrieved atmospheric state of peroxyacetyl nitrate (PAN), and formal uncertainties measured by the CrIS instruments on the Suomi-NPP satellite. The reanalysis stream summary product is global for the time period from 2015-12-01 to 2023-05-18. The NASA TRopospheric Ozone and Precursors from Earth System Sounding (TROPESS) project, uses an optimal estimation algorithm, known as the MUlti-SpEctra, MUlti-SpEcies, Multi-SEnsors (MUSES).The data files are written in the netCDF version 4 file format, and each file contains one day of data. The data have a spatial resolution of 14 km (CrIS nadir FOV), and are reported at 16 vertical levels from the surface to 0.1 hPa. The principal investigator for the TROPESS project is Kevin W. Bowman.

Laboratory data supporting "Quantitative constraints on autoxidation and dimer formation from direct probing of monoterpene-derived peroxy radical chemistry" by Zhao, Thornton, and Pye. Abstract: Organic peroxy radicals (RO2) are key intermediates in the atmospheric degradation of organic matter and fuel combustion, but to date, few direct studies of specific RO2 in complex reaction systems exist, leading to large gaps in our understanding of their fate. We show, using direct, speciated measurements of a suite of RO2 and gas-phase dimers from O3-initiated oxidation of α-pinene that ~150 gaseous dimers (C16-20H24-34O4-13) are primarily formed through RO2 cross-reactions, with a typical rate constant of 0.75-2×10-12 cm3 molecule-1 s-1 and a lower-limit dimer formation branching ratio of 4%. These findings imply a gaseous dimer yield that varies strongly with nitric oxide (NO) concentrations, of at least 0.2-2.5% by mole (0.5-6.6% by mass) for conditions typical of forested regions with low to moderate anthropogenic influence (i.e., ≤ 50 ppt NO). Given their very low volatility, the gaseous C16-20 dimers provide a potentially important organic medium for initial particle formation, and alone can explain 5-60% of α-pinene secondary organic aerosol mass yields measured at atmospherically relevant particle mass loadings. The responses of RO2, dimers, and highly-oxygenated multifunctional compounds (HOM) to reacted α-pinene concentration and NO imply that an average ~20% of primary α-pinene RO2 from OH reaction and 10% from ozonolysis autoxidize at 3-10 s-1 and ≥ 1 s-1, respectively, confirming both oxidation pathways produce HOM efficiently, even at higher NO concentrations typical of urban areas. Thus, gas-phase dimer formation and RO2 autoxdiation are ubiquitous sources of low-volatility organic compounds capable of contributing significantly to atmospheric new particle formation and growth. This dataset is associated with the following publication: Zhao, Y., J. Thornton, and H. Pye. Quantitative constraints on autoxidation and dimer formation from direct probing of monoterpene-derived peroxy radical chemistry. PNAS (PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES). National Academy of Sciences, WASHINGTON, DC, USA, 115(48): 12142-12147, (2018).

Laboratory data supporting "Quantitative constraints on autoxidation and dimer formation from direct probing of monoterpene-derived peroxy radical chemistry" by Zhao, Thornton, and Pye. Abstract: Organic peroxy radicals (RO2) are key intermediates in the atmospheric degradation of organic matter and fuel combustion, but to date, few direct studies of specific RO2 in complex reaction systems exist, leading to large gaps in our understanding of their fate. We show, using direct, speciated measurements of a suite of RO2 and gas-phase dimers from O3-initiated oxidation of α-pinene that ~150 gaseous dimers (C16-20H24-34O4-13) are primarily formed through RO2 cross-reactions, with a typical rate constant of 0.75-2×10-12 cm3 molecule-1 s-1 and a lower-limit dimer formation branching ratio of 4%. These findings imply a gaseous dimer yield that varies strongly with nitric oxide (NO) concentrations, of at least 0.2-2.5% by mole (0.5-6.6% by mass) for conditions typical of forested regions with low to moderate anthropogenic influence (i.e., ≤ 50 ppt NO). Given their very low volatility, the gaseous C16-20 dimers provide a potentially important organic medium for initial particle formation, and alone can explain 5-60% of α-pinene secondary organic aerosol mass yields measured at atmospherically relevant particle mass loadings. The responses of RO2, dimers, and highly-oxygenated multifunctional compounds (HOM) to reacted α-pinene concentration and NO imply that an average ~20% of primary α-pinene RO2 from OH reaction and 10% from ozonolysis autoxidize at 3-10 s-1 and ≥ 1 s-1, respectively, confirming both oxidation pathways produce HOM efficiently, even at higher NO concentrations typical of urban areas. Thus, gas-phase dimer formation and RO2 autoxdiation are ubiquitous sources of low-volatility organic compounds capable of contributing significantly to atmospheric new particle formation and growth. This dataset is associated with the following publication: Zhao, Y., J. Thornton, and H. Pye. Quantitative constraints on autoxidation and dimer formation from direct probing of monoterpene-derived peroxy radical chemistry. PNAS (PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES). National Academy of Sciences, WASHINGTON, DC, USA, 115(48): 12142-12147, (2018).