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Article ; Online: Presence of aromatic-rich organic matter and its characterization in grout materials: Implications for radionuclide immobilization

Lin, Peng / Xu, Chen / Kaplan, Daniel I. / Yeager, Chris M. / Xing, Wei / Nichols, Ralph / Santschi, Peter H.

Journal of Environmental Radioactivity. 2023, p.107183-

2023 , Page(s) 107183–

Abstract: Grout materials are commonly used to immobilize low-level radioactive waste. Organic moieties can be unintentionally present in common ingredients used to make these grout waste forms, which may result in the formation of organo-radionuclide species. ... ...

Abstract	Grout materials are commonly used to immobilize low-level radioactive waste. Organic moieties can be unintentionally present in common ingredients used to make these grout waste forms, which may result in the formation of organo-radionuclide species. These species can positively or negatively affect the immobilization efficiency. However, the presence of organic carbon compounds is rarely considered in models or characterized chemically. Here, we quantify the organic pool of grout formulations with and without slag, as well as the individual dry ingredients used to make the grout samples (ordinary Portland cement (OPC), slag and fly ash), including total organic carbon (TOC) and black carbon, followed by aromaticity evaluation and molecular characterization via Electro Spray Ionization Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FTICRMS). All dry grout ingredients contained significant amounts of organic carbon, ranging from 550 mg/kg to 6250 mg/kg for the TOC pool, with an averaged abundance of 2933 ± 2537 mg/kg, of which 60 ± 29% was composed of black carbon. The significant abundance of a black carbon pool implies the presence of the aromatic-like compounds, which was further identified by both phosphate buffer-assisted aromaticity evaluation (e.g., >1000 mg-C/kg as aromatic-like carbon in the OPC) and dichloromethane (DCM) extraction with ESI-FTICRMS analysis. Besides aromatic-like compounds, other organic moieties were also detected in the OPC, such as carboxyl-containing aliphatic molecules. While the organic compound only consists of minor fractions of the grout materials investigated, our observations of the presence of various radionuclide-binding organic moieties suggests the potential formation of organo-radionuclides, such as radioiodine, which might be present at lower molar concentrations than TOC. Evaluating the role of organic carbon complexation in controlling the disposed radionuclides, especially for those radionuclides with strong association with organic carbon, has important implications for the long-term immobilization of radioactive waste in grout systems.
Keywords	carbon sinks ; cement ; fly ash ; ionization ; mass spectrometry ; methylene chloride ; phosphates ; radioactive waste ; radioactivity ; slags ; total organic carbon ; Iodine ; ESI-FTICR-MS ; Aromaticity ; Black carbon
Language	English
Publishing place	Elsevier Ltd
Document type	Article ; Online
Note	Pre-press version
ZDB-ID	1483112-0
ISSN	1879-1700 ; 0265-931X
ISSN (online)	1879-1700
ISSN	0265-931X
DOI	10.1016/j.jenvrad.2023.107183
Database	NAL-Catalogue (AGRICOLA)

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Article: Large seasonal fluctuations of groundwater radioiodine speciation and concentrations in a riparian wetland in South Carolina

Kaplan, Daniel I. / Nichols, Ralph / Xu, Chen / Lin, Peng / Yeager, Chris / Santschi, Peter H.

Science of the total environment. 2022 Apr. 10, v. 816

2022

Abstract: Recent studies evaluating multiple years of groundwater radioiodine (¹²⁹I) concentration in a riparian wetland located in South Carolina, USA identified strong seasonal concentration fluctuations, such that summer concentrations were much greater than ... ...

Abstract	Recent studies evaluating multiple years of groundwater radioiodine (¹²⁹I) concentration in a riparian wetland located in South Carolina, USA identified strong seasonal concentration fluctuations, such that summer concentrations were much greater than winter concentrations. These fluctuations were observed only in the wetlands but not in the upland portion of the plume and only with ¹²⁹I, and not with other contaminants of anthropogenic origin: nitrate/nitrite, strontium-90, technecium-99, tritium, or uranium. This unexplained observation was hypothesized to be the result of strongly coupled processes involving hydrology, water temperature, microbiology, and chemistry. To test this hypothesis, an extensive historical groundwater database was evaluated, and additional measurements of total iodine and iodine speciation were made from recently collected samples. During the summer, the water table decreased by as much as 0.7 m, surface water temperature increased by as much as 15 °C, and total iodine concentrations were consistently greater (up to 680%) than the following winter months. Most of the additional iodine observed in the summer could be attributed to proportional gains in organo-iodine, and not iodide or iodate. Furthermore, ¹²⁹I concentrations were observed to be two-orders-of-magnitude greater at the bottom of the upland aquifer than at the top. A coupled hydrological and biogeochemical conceptual model is proposed to tie these observations together. First, as the surface water temperature increased during the summer, microbial activity was enhanced, which in turn stimulated the formation of mobile organo-I. Hydrological processes were also likely involved in the observed iodine seasonal changes: (1) as the water table decreased in summer, the remaining upland water entering the wetland was comprised of a greater proportion of water containing elevated iodine concentrations from the low depths, and (2) water flow paths in summer changed such that the wells intercepted more of the contaminant plume and less of the diluting rainwater (due to evapotranspiration) and streamwater (as the lower levels promote a predominantly recharging system). These results underscore the importance of coupled processes influencing contaminant concentrations, and the need to assess seasonal contaminant variations to optimize long-term monitoring programs of wetlands.
Keywords	aquifers ; chemistry ; databases ; environment ; evapotranspiration ; groundwater ; highlands ; iodates ; iodides ; iodine ; microbial activity ; models ; nitrates ; nitrites ; rain ; summer ; surface water temperature ; tritium ; uranium ; water flow ; water table ; wetlands ; South Carolina
Language	English
Dates of publication	2022-0410
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	121506-1
ISSN	1879-1026 ; 0048-9697
ISSN (online)	1879-1026
ISSN	0048-9697
DOI	10.1016/j.scitotenv.2021.151548
Database	NAL-Catalogue (AGRICOLA)

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Article: Iodide uptake by forest soils is principally related to the activity of extracellular oxidases.

Grandbois, Russell M / Santschi, Peter H / Xu, Chen / Mitchell, Joshua M / Kaplan, Daniel I / Yeager, Chris M

Frontiers in chemistry

2023 Volume 11, Page(s) 1105641

Abstract: ... ...

Abstract	129
Language	English
Publishing date	2023-03-02
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2711776-5
ISSN	2296-2646
ISSN	2296-2646
DOI	10.3389/fchem.2023.1105641
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Presence of aromatic-rich organic matter and its characterization in grout materials: Implications for radionuclide immobilization.

Lin, Peng / Xu, Chen / Kaplan, Daniel I / Yeager, Chris M / Xing, Wei / Nichols, Ralph / Santschi, Peter H

Journal of environmental radioactivity

2023 Volume 263, Page(s) 107183

Abstract	Grout materials are commonly used to immobilize low-level radioactive waste. Organic moieties can be unintentionally present in common ingredients used to make these grout waste forms, which may result in the formation of organo-radionuclide species. These species can positively or negatively affect the immobilization efficiency. However, the presence of organic carbon compounds is rarely considered in models or characterized chemically. Here, we quantify the organic pool of grout formulations with and without slag, as well as the individual dry ingredients used to make the grout samples (ordinary Portland cement (OPC), slag and fly ash), including total organic carbon (TOC) and black carbon, followed by aromaticity evaluation and molecular characterization via Electro Spray Ionization Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FTICRMS). All dry grout ingredients contained significant amounts of organic carbon, ranging from 550 mg/kg to 6250 mg/kg for the TOC pool, with an averaged abundance of 2933 ± 2537 mg/kg, of which 60 ± 29% was composed of black carbon. The significant abundance of a black carbon pool implies the presence of the aromatic-like compounds, which was further identified by both phosphate buffer-assisted aromaticity evaluation (e.g., >1000 mg-C/kg as aromatic-like carbon in the OPC) and dichloromethane (DCM) extraction with ESI-FTICRMS analysis. Besides aromatic-like compounds, other organic moieties were also detected in the OPC, such as carboxyl-containing aliphatic molecules. While the organic compound only consists of minor fractions of the grout materials investigated, our observations of the presence of various radionuclide-binding organic moieties suggests the potential formation of organo-radionuclides, such as radioiodine, which might be present at lower molar concentrations than TOC. Evaluating the role of organic carbon complexation in controlling the disposed radionuclides, especially for those radionuclides with strong association with organic carbon, has important implications for the long-term immobilization of radioactive waste in grout systems.
MeSH term(s)	Radioactive Waste ; Iodine Radioisotopes/chemistry ; Radiation Monitoring ; Carbon ; Mass Spectrometry
Chemical Substances	Radioactive Waste ; Iodine Radioisotopes ; Carbon (7440-44-0)
Language	English
Publishing date	2023-04-23
Publishing country	England
Document type	Journal Article
ZDB-ID	1483112-0
ISSN	1879-1700 ; 0265-931X
ISSN (online)	1879-1700
ISSN	0265-931X
DOI	10.1016/j.jenvrad.2023.107183
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Uranium Biogeochemistry in the Rhizosphere of a Contaminated Wetland.

Kaplan, Daniel I / Boyanov, Maxim I / Losey, Nathaniel A / Lin, Peng / Xu, Chen / O'Loughlin, Edward J / Santschi, Peter H / Xing, Wei / Kuhne, Wendy W / Kemner, Kenneth M

Environmental science & technology

2024 Volume 58, Issue 14, Page(s) 6381–6390

Abstract: The objective of this study was to determine if U sediment concentrations in a U-contaminated wetland located within the Savannah River Site, South Carolina, were greater in the rhizosphere than in the nonrhizosphere. U concentrations were as much as ... ...

Abstract	The objective of this study was to determine if U sediment concentrations in a U-contaminated wetland located within the Savannah River Site, South Carolina, were greater in the rhizosphere than in the nonrhizosphere. U concentrations were as much as 1100% greater in the rhizosphere than in the nonrhizosphere fractions; however and importantly, not all paired samples followed this trend. Iron (but not C, N, or S) concentrations were significantly enriched in the rhizosphere. XAS analyses showed that in both sediment fractions, U existed as UO
MeSH term(s)	Ferric Compounds ; Wetlands ; Rhizosphere ; Uranium ; RNA, Ribosomal, 16S ; Iron ; Oxides/analysis ; Oxidation-Reduction ; Geologic Sediments/microbiology
Chemical Substances	Ferric Compounds ; Uranium (4OC371KSTK) ; RNA, Ribosomal, 16S ; Iron (E1UOL152H7) ; Oxides
Language	English
Publishing date	2024-03-28
Publishing country	United States
Document type	Journal Article
ISSN	1520-5851
ISSN (online)	1520-5851
DOI	10.1021/acs.est.3c10481
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Large seasonal fluctuations of groundwater radioiodine speciation and concentrations in a riparian wetland in South Carolina.

Kaplan, Daniel I / Nichols, Ralph / Xu, Chen / Lin, Peng / Yeager, Chris / Santschi, Peter H

The Science of the total environment

2021 Volume 816, Page(s) 151548

Abstract: Recent studies evaluating multiple years of groundwater radioiodine ( ...

Abstract	Recent studies evaluating multiple years of groundwater radioiodine (
MeSH term(s)	Groundwater ; Iodine Radioisotopes/analysis ; Seasons ; South Carolina ; Wetlands
Chemical Substances	Iodine Radioisotopes
Language	English
Publishing date	2021-11-13
Publishing country	Netherlands
Document type	Journal Article
ZDB-ID	121506-1
ISSN	1879-1026 ; 0048-9697
ISSN (online)	1879-1026
ISSN	0048-9697
DOI	10.1016/j.scitotenv.2021.151548
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: 1H-13C heteronuclear single quantum coherence NMR evidence for iodination of natural organic matter influencing organo-iodine mobility in the environment

Xu, Chen / Lin, Peng / Garimella, Ravindranath / Li, Dien / Xing, Wei / Patterson, Nicole E. / Kaplan, Daniel I. / Yeager, Chris M. / Hatcher, Patrick G. / Santschi, Peter H.

Science of the total environment. 2022 Mar. 25, v. 814

2022

Abstract: The complex biogeochemical behavior of iodine (I) isotopes and their interaction with natural organic matter (NOM) pose a challenge for transport models. Here, we present results from iodination experiments with humic acid (HA) and fulvic acid (FA) using ...

Abstract	The complex biogeochemical behavior of iodine (I) isotopes and their interaction with natural organic matter (NOM) pose a challenge for transport models. Here, we present results from iodination experiments with humic acid (HA) and fulvic acid (FA) using ¹H-¹³C heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy. Even though not a quantitative approach, ¹H-¹³C HSQC NMR corroborated that iodination of NOM occurs primarily through aromatic electrophilic substitution of proton by I, and also revealed how iodination chemically alters HA and FA in a manner that potentially affects the mobility of iodinated NOM in the environment. Three types of iodination experiments were conducted with HA and FA: a) non-enzymatic iodination by IO₃⁻ (pH 3) and I⁻ (pH 4 and 7), b) addition of lactoperoxidase to promote I⁻-iodination in the presence of the co-substrate, H₂O₂ (pH 7), and c) addition of laccase for facilitating I⁻-iodination in the presence of O₂, with or without a mediator (pH 4). When mediators or H₂O₂ were present, extracellular oxidases and peroxidases enhanced I⁻ incorporation into NOM by between 54% and 3400%. Iodination of HA, which was less than that of FA, enhanced HA's stability (inferred from increases in aliphatic compounds, decreases in carbohydrate moieties, and thus increased molecular hydrophobicity) yet reduced HA's tendency to incorporate more iodine. As such, HA is expected to act more as a sink for iodine in the environment. In contrast, iodination of FA appeared to generate additional iodine binding sites, which resulted in greater iodine uptake capability and enhanced mobility (inferred from decreases in aliphatic compounds, increases in carbohydrates, and thus decreases in molecular hydrophobicity). These results indicate that certain NOM moieties may enhance while others may inhibit radioiodine mobility in the aqueous environment.
Keywords	Lewis acids ; carbohydrates ; environment ; fulvic acids ; humic acids ; hydrophobicity ; iodination ; iodine ; laccase ; nuclear magnetic resonance spectroscopy ; pH ; peroxidase ; quantitative analysis ; quantum mechanics
Language	English
Dates of publication	2022-0325
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	121506-1
ISSN	1879-1026 ; 0048-9697
ISSN (online)	1879-1026
ISSN	0048-9697
DOI	10.1016/j.scitotenv.2021.152546
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Carbon capture by macroalgae Sarcodia suae using aquaculture wastewater and solar energy for cooling in subtropical regions

Weerakkody, W. Sanjaya / Ling, Ka Hin / Hsieh, Hsueh-Han / Abedneko, Vicente G. / Shyu, Jeng-Feng / Lee, Tse-Min / Shi, Yongyan / Ranatunga, R.R.M.K.P. / Santschi, Peter H. / Hung, Chin-Chang

Science of the Total Environment. 2023 Jan., v. 855 p.158850-

2023

Abstract: Rapid growth in the aquaculture industry and corresponding increases in nutrient and organic carbon levels in coastal regions can lead to eutrophication and increased greenhouse gas emissions. Macroalgae are the organisms primarily responsible for the ... ...

Abstract	Rapid growth in the aquaculture industry and corresponding increases in nutrient and organic carbon levels in coastal regions can lead to eutrophication and increased greenhouse gas emissions. Macroalgae are the organisms primarily responsible for the capture of CO₂ and removal of nutrients from coastal waters. In the current study, we developed a novel wastewater treatment system in which the red macroalga, Sarcordia suae, is used to capture CO₂ under thermostatic conditions in subtropical regions. In 2020 (without temperature control), the carbon capture rate (CCR) of Sarcordia suae varied considerably with the season: winter/spring (2.1–3.9 g-C m⁻² d⁻¹) and summer (0.09 g-C m⁻² d⁻¹). In 2021, solar powered cooling reduced summer seawater temperatures from 31 to 33 °C to 23–25 °C with a corresponding increase in the mean CCR: winter/spring (2–7 g-C m⁻² d⁻¹) and summer (1.33 g-C m⁻² d⁻¹). The proposed aquaculture wastewater system proved highly efficient in removing nitrogen (20.7 mg-N g⁻¹ DW d⁻¹, DW = dry weight) and phosphorus (4.4 mg-P g⁻¹ DW d⁻¹). Furthermore, the high density of Sarcodia (1.10 ± 0.03 g cm⁻³) would permit the harvesting and subsequent dumping of Sarcodia in deep off-shore waters. This study demonstrated a low-cost land-based seaweed cultivation system for capturing CO₂ and excess nutrients from aquaculture wastewater year-round under temperature controlled environments in subtropical regions.
Keywords	aquaculture industry ; carbon dioxide ; cooling ; environment ; eutrophication ; greenhouse gases ; macroalgae ; nitrogen ; organic carbon ; phosphorus ; seawater ; seaweed culture ; solar energy ; spring ; summer ; temperature ; wastewater ; wastewater treatment ; winter ; Carbon catch and sequestration (CCS) ; Nutrient removal ; Seaweed ; Carbon neutrality ; Taiwan
Language	English
Dates of publication	2023-01
Publishing place	Elsevier B.V.
Document type	Article ; Online
Note	Use and reproduction
ZDB-ID	121506-1
ISSN	1879-1026 ; 0048-9697
ISSN (online)	1879-1026
ISSN	0048-9697
DOI	10.1016/j.scitotenv.2022.158850
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Corrigendum to "Carbon capture by macroalgae Sarcodia suae using aquaculture wastewater and solar energy for cooling in subtropical regions" [Sci. Total Environ. 855 (2023) 158850].

Weerakkody, W Sanjaya / Ling, Ka Hin / Hsieh, Hsueh-Han / Abedneko, Vicente G / Shyu, Jeng-Feng / Lee, Tse-Min / Shih, Yung-Yen / Ranatunga, R R M K P / Santschi, Peter H / Hung, Chin-Chang

The Science of the total environment

2023 Volume 883, Page(s) 163735

Language	English
Publishing date	2023-05-01
Publishing country	Netherlands
Document type	Published Erratum
ZDB-ID	121506-1
ISSN	1879-1026 ; 0048-9697
ISSN (online)	1879-1026
ISSN	0048-9697
DOI	10.1016/j.scitotenv.2023.163735
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: The Interplay of Phototrophic and Heterotrophic Microbes Under Oil Exposure: A Microcosm Study.

Kamalanathan, Manoj / Schwehr, Kathleen A / Labonté, Jessica M / Taylor, Christian / Bergen, Charles / Patterson, Nicole / Claflin, Noah / Santschi, Peter H / Quigg, Antonietta

Frontiers in microbiology

2021 Volume 12, Page(s) 675328

Abstract: Microbial interactions influence nearly one-half of the global biogeochemical flux of major elements of the marine ecosystem. Despite their ecological importance, microbial interactions remain poorly understood and even less is known regarding the ... ...

Abstract	Microbial interactions influence nearly one-half of the global biogeochemical flux of major elements of the marine ecosystem. Despite their ecological importance, microbial interactions remain poorly understood and even less is known regarding the effects of anthropogenic perturbations on these microbial interactions. The Deepwater Horizon oil spill exposed the Gulf of Mexico to ∼4.9 million barrels of crude oil over 87 days. We determined the effects of oil exposure on microbial interactions using short- and long-term microcosm experiments with and without Macondo surrogate oil. Microbial activity determined using radiotracers revealed that oil exposure negatively affected substrate uptake by prokaryotes within 8 h and by eukaryotes over 72 h. Eukaryotic uptake of heterotrophic exopolymeric substances (EPS) was more severely affected than prokaryotic uptake of phototrophic EPS. In addition, our long-term exposure study showed severe effects on photosynthetic activity. Lastly, changes in microbial relative abundances and fewer co-occurrences among microbial species were mostly driven by photosynthetic activity, treatment (control vs. oil), and prokaryotic heterotrophic metabolism. Overall, oil exposure affected microbial co-occurrence and/or interactions possibly by direct reduction in abundance of one of the interacting community members and/or indirect by reduction in metabolism (substrate uptake or photosynthesis) of interacting members.
Language	English
Publishing date	2021-08-02
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2587354-4
ISSN	1664-302X
ISSN	1664-302X
DOI	10.3389/fmicb.2021.675328
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