1
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Hu Y, Xue Q, Chen H, Guo H, Carroll KC, Wang S. Mechanistic insight into Cr(VI) retention by Si-containing ferrihydrite. J Environ Sci (China) 2024; 139:217-225. [PMID: 38105049 DOI: 10.1016/j.jes.2023.05.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/21/2023] [Accepted: 05/28/2023] [Indexed: 12/19/2023]
Abstract
Hexavalent chromium [Cr(VI)] causes serious harm to the environment due to its high toxicity, solubility, and mobility. Ferrihydrites (Fh) are the main adsorbent and trapping agent of Cr(VI) in soils and aquifers, and they usually coexist with silicate (Si), forming Si-containing ferrihydrite (Si-Fh) mixtures. However, the mechanism of Cr(VI) retention by Si-Fh mixtures is poorly understood. In this study, the behaviors and mechanisms of Cr(VI) adsorption onto Si-Fh with different Si/Fe molar ratios was investigated. Transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and other techniques were used to characterize Si-Fh and Cr(VI)-loading of Si-Fh. The results show that specific surface area of Si-Fh increases gradually with increasing Si/Fe ratios, but Cr(VI) adsorption on Si-Fh decreases with increasing Si/Fe ratios. This is because with an increase in Si/Fe molar ratio, the point of zero charge of Si-Fh gradually decreases and electrostatic repulsion between Si-Fh and Cr(VI) increases. However, the complexation of Cr(VI) is enhanced due to the increase in adsorbed hydroxyl (A-OH-) on Si-Fh with increasing Si/Fe molar ratio, which partly counteracts the effect of the electrostatic repulsion. Overall, the increase in the electrostatic repulsion has a greater impact on adsorption than the additional complexation with Si-Fh. Density functional theory calculation further supports this observation, showing the increases in electron variation of bonding atoms and reaction energies of inner spherical complexes with the increase in Si/Fe ratio.
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Affiliation(s)
- Ying Hu
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
| | - Qiang Xue
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China.
| | - Honghan Chen
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences, Beijing 100083, China
| | - Huaming Guo
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China.
| | - Kenneth C Carroll
- Plant & Environmental Science, New Mexico State University, NM 88003, USA
| | - Song Wang
- Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun 130023, China
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2
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Zhan C, Dai Z, Yin S, Carroll KC, Soltanian MR. Conceptualizing future groundwater models through a ternary framework of multisource data, human expertise, and machine intelligence. Water Res 2024; 257:121679. [PMID: 38696982 DOI: 10.1016/j.watres.2024.121679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/04/2024]
Abstract
Groundwater models are essential for understanding aquifer systems behavior and effective water resources spatio-temporal distributions, yet they are often hindered by challenges related to model assumptions, parametrization, uncertainty, and computational efficiency. Machine intelligence, especially deep learning, promises a paradigm shift in overcoming these challenges. A critical examination of existing machine-driven methods reveals the inherent limitations, particularly in terms of the interpretability and the ability to generalize findings. To overcome these challenges, we develop a ternary framework that synergizes the valuable insights from multisource data, human expertise, and machine intelligence. This framework capitalizes on the distinct strengths of each element: the value and relevance of multisource data, the innovative capacity of human expertise, and the analytical efficiency of machine intelligence. Our goal is to conceptualize sustainable water management practices and enhance our understanding and predictive capabilities of groundwater systems. Unlike approaches that rely solely on abundant data, our framework emphasizes the quality and strategic use of available data, combined with human intellect and advanced computing, to overcome current limitations and pave the way for more realistic groundwater simulations.
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Affiliation(s)
- Chuanjun Zhan
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China
| | - Zhenxue Dai
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China; College of Construction Engineering, Jilin University, Changchun 130026, China; Institute of Intelligent Simulation and Early Warning for Subsurface Environment, Jilin University, Changchun 130026, China.
| | - Shangxian Yin
- North China Institute of Science & Technology, Langfang 065201, China.
| | - Kenneth C Carroll
- Department of Plant & Environmental Science, New Mexico State University, Las Cruces, NM, USA
| | - Mohamad Reza Soltanian
- Departments of Geosciences and Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA
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3
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Carroll KC, Brusseau ML, Tick GR, Soltanian MR. Rethinking pump-and-treat remediation as maximizing contaminated groundwater. Sci Total Environ 2024; 918:170600. [PMID: 38336056 DOI: 10.1016/j.scitotenv.2024.170600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/09/2024] [Accepted: 01/29/2024] [Indexed: 02/12/2024]
Abstract
For over half a century, the United States has developed water quality regulations (e.g., Safe Drinking Water Act), which has been accompanied by innumerable advances in contaminant transport and fate, site characterization, and remediation. Since the 1980s, "pump-and-treat" techniques have been the most widely used methods for groundwater contamination remediation. By 1982, pump-and-treat was included in 100 % of the U.S. Superfund groundwater remedy decisions, but applications decreased continuously after 1992. This was likely associated with the documented limitations of pump-and-treat for achieving complete remediation with site closure. Several factors can limit the effectiveness of pump-and-treat, a primary one being that contaminant mass residing in NAPL, sorbed, and low-permeability matrices is not removed in an effective or efficient manner. This ineffectiveness leads to extended cleanup times and the generation of enormous volumes of extracted groundwater, in effect creating conditions of maximizing the amount of contaminated groundwater needing treatment. We highlight a means by which to reassess our approach to remediation by recognizing that pump-and-treat, due to its well-documented limitations, often maximizes the generation of contaminated groundwater.
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Affiliation(s)
- Kenneth C Carroll
- New Mexico State University, Department of Plant and Environmnetal Sciences, Las Cruces, NM, USA.
| | - Mark L Brusseau
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, USA
| | - Geoffrey R Tick
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL 35487, USA
| | - Mohamad R Soltanian
- Department of Geosciences, Department of Environmental Engineering, University of Cincinnati, Cincinnati, OH, USA
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4
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Doughman MS, O'Shea KE, Qafoku NP, Emerson HP, Szecsody JE, Carroll KC, Katsenovich YP. Impact of chromium (VI) as a co-contaminant on the sorption and co-precipitation of uranium (VI) in sediments under mildly alkaline oxic conditions. J Environ Manage 2024; 349:119463. [PMID: 37972490 DOI: 10.1016/j.jenvman.2023.119463] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/16/2023] [Accepted: 10/23/2023] [Indexed: 11/19/2023]
Abstract
Uranium (U) waste, generated at a variety of mines and nuclear production sites, migrates in the subsurface, posing a serious threat to contaminate groundwater systems. In this study, batch equilibrium and kinetic experiments, geochemical modeling and solid phase characterization were conducted to investigate the impact of Cr(VI), a common co-contaminant, on the adsorption of U(VI) to quartz, plagioclase feldspar, and carbonate-dominated sediment (≤2 mm). Batch experiments were performed under slightly alkaline conditions (7.80 ± 0.18) and in the presence of major groundwater components (Ca2+, Mg2+, Na+, K+, carbonate, chloride, and sulfate) at different U(VI):Cr(VI) molar ratios 10:1, 1:1, and 1:10 at lower U(VI) concentration (10.5 μM [2.5 mg/L]) and at U(VI):Cr(VI) molar ratios of 168:1.05, 168:10.5, 168:105, 1:1, and 1:10 at higher U(VI) concentration (168 μM [40 mg/L]). At the low U(VI) concentration (10.5 μM [2.5 mg/L]), the distribution coefficients (Kd) were unchanged for the 10:1 and 1:1 U:Cr molar ratios indicating an excess of available U(VI) adsorption sites on the sediment. However, the U(VI) Kd values in the presence of Cr(VI) at the 1:10 M ratio decreased suggesting competition between U(VI) and Cr(VI) for adsorption sites. At the higher U(VI) concentration (168 μM [40 mg/L]), the Kd values were unaffected by U(VI):Cr(VI) molar ratios of 168:1.05, 168:10.5, 168:105, again indicating an excess of available sediment adsorption sites. At U:Cr molar ratios 1:1 and 1:10, there was a slight increase in Kd for U(VI) possibly reflecting an increase in inner-sphere binding of uranyl carbonate complexes. The adsorption process followed pseudo second-order kinetic parameters. These results indicate the sediment affinity for U(VI) adsorption appears to be largely independent of Cr(VI) under our experimental conditions. The intraparticle diffusion modeling of U(VI) adsorption to the sediment suggests a multi-step process, including film and intraparticle diffusion. The intraparticle diffusion stage remained constant in the presence of Cr(VI) suggesting the rate determining factors for overall equilibrium adsorption process for U(VI) was independent of Cr(VI). Understanding the mobility of U(VI) under natural conditions as simulated in our study is critical in developing effective remediation strategies and effective monitored natural attenuation (MNA) following the remediation of contaminated sites.
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Affiliation(s)
- Mariah S Doughman
- Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL, 33174, USA; Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th St, Miami, FL, 33199, USA.
| | - Kevin E O'Shea
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th St, Miami, FL, 33199, USA
| | - Nikolla P Qafoku
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99354, USA; Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Hilary P Emerson
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99354, USA
| | - James E Szecsody
- Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99354, USA
| | - Kenneth C Carroll
- New Mexico State University, Department of Plant and Environmental Sciences, Dept. 3Q Las Cruces, NM, 88003, USA
| | - Yelena P Katsenovich
- Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL, 33174, USA.
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5
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Hitzelberger M, Khan NA, Mohamed RAM, Brusseau ML, Carroll KC. PFOS Mass Flux Reduction/Mass Removal: Impacts of a Lower-Permeability Sand Lens within Otherwise Homogeneous Systems. Environ Sci Technol 2022; 56:13675-13685. [PMID: 36126139 PMCID: PMC9664819 DOI: 10.1021/acs.est.2c02193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Perfluorooctane sulfonic acid (PFOS) is one of the most common per- and polyfluoroalkyl substances (PFAS) and is a significant risk driver for these emerging contaminants of concern. A series of two-dimensional flow cell experiments was conducted to investigate the impact of flow field heterogeneity on the transport, attenuation, and mass removal of PFOS. A simplified model heterogeneous system was employed consisting of a lower-permeability fine sand lens placed within a higher-permeability coarse sand matrix. Three nonreactive tracers with different aqueous diffusion coefficients, sodium chloride, pentafluorobenzoic acid, and β-cyclodextrin, were used to characterize the influence of diffusive mass transfer on transport and for comparison to PFOS results. The results confirm that the attenuation and subsequent mass removal of the nonreactive tracers and PFOS were influenced by mass transfer between the hydraulically less accessible zone and the coarser matrix (i.e., back diffusion). A mathematical model was used to simulate flow and transport, with the values for all input parameters determined independently. The model predictions provided good matches to the measured breakthrough curves, as well as to plots of reductions in mass flux as a function of mass removed. These results reveal the importance of molecular diffusion and pore water velocity variability even for systems with relatively minor hydraulic conductivity heterogeneity. The impacts of the diffusive mass transfer limitation were quantified using an empirical function relating reductions in contaminant mass flux (MFR) to mass removal (MR). Multi-step regression was used to quantify the nonlinear, multi-stage MFR/MR behavior observed for the heterogeneous experiments. The MFR/MR function adequately reproduced the measured data, which suggests that the MFR/MR approach can be used to evaluate PFOS removal from heterogeneous media.
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Affiliation(s)
- Michael Hitzelberger
- New Mexico State University Department of Plant and Environmnetal Sciences, Las Cruces, New Mexico 88003, United States
| | - Naima A Khan
- New Mexico State University Department of Plant and Environmnetal Sciences, Las Cruces, New Mexico 88003, United States
| | - Ruba A M Mohamed
- New Mexico State University Department of Plant and Environmnetal Sciences, Las Cruces, New Mexico 88003, United States
| | - Mark L Brusseau
- University of Arizona Environmental Science Department, University of Arizona, Tucson, Arizona 85721, United States
| | - Kenneth C Carroll
- New Mexico State University Department of Plant and Environmnetal Sciences, Las Cruces, New Mexico 88003, United States
- University of Arizona Hydrology and Atmospheric Sciences Department, University of Arizona, Tucson, Arizona 85721, United States
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6
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Johnson GR, Brusseau ML, Carroll KC, Tick GR, Duncan CM. Global distributions, source-type dependencies, and concentration ranges of per- and polyfluoroalkyl substances in groundwater. Sci Total Environ 2022; 841:156602. [PMID: 35690215 PMCID: PMC9653090 DOI: 10.1016/j.scitotenv.2022.156602] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 05/06/2022] [Accepted: 06/06/2022] [Indexed: 04/13/2023]
Abstract
A meta-analysis was conducted of published literature reporting concentrations of per- and polyfluoroalkyl substances (PFAS) in groundwater for sites distributed in 20 countries across the globe. Data for >35 PFAS were aggregated from 96 reports published from 1999 to 2021. The final data set comprises approximately 21,000 data points after removal of time-series and duplicate samples as well as non-detects. The reported concentrations range over many orders of magnitude, from ng/L to mg/L levels. Distinct differences in concentration ranges are observed between sites located within or near sources versus those that are not. Perfluorooctanoic acid (PFOA), ranging from <0.03 ng/L to ~7 mg/L, and perfluorooctanesulfonic acid (PFOS), ranging from 0.01 ng/L to ~5 mg/L, were the two most reported PFAS. The highest PFAS concentration in groundwater is ~15 mg/L reported for the replacement-PFAS 6:2 fluorotelomer sulfonate (6:2 FTS). Maximum reported groundwater concentrations for PFOA and PFOS were compared to concentrations reported for soils, surface waters, marine waters, and precipitation. Soil concentrations are generally significantly higher than those reported for the other media. This accrues to soil being the primary entry point for PFAS release into the environment for many sites, as well as the generally significantly greater retention capacity of soil compared to the other media. The presence of PFAS has been reported for all media in all regions tested, including areas that are far removed from specific PFAS sources. This gives rise to the existence of a "background" concentration of PFAS that must be accounted for in both regional and site-specific risk assessments. The presence of this background is a reflection of the large-scale use of PFAS, their general recalcitrance, and the action of long-range transport processes that distribute PFAS across regional and global scales. This ubiquitous distribution has the potential to significantly impact the quality and availability of water resources in many regions. In addition, the pervasive presence of PFAS in the environment engenders concerns for impacts to ecosystem and human health.
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7
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Farooq U, Wang F, Shahzad MK, Carroll KC, Lyu S, Wang X. Study the activation mechanism of peroxymonosulfate in iron copper systems for trichloroethane degradation. Chemical Engineering Journal Advances 2022. [DOI: 10.1016/j.ceja.2022.100343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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8
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Tang J, Wang Y, Xue Q, Liu F, Carroll KC, Lu X, Zhou T, Wang D. A mechanistic study of ciprofloxacin adsorption by goethite in the presence of silver and titanium dioxide nanoparticles. J Environ Sci (China) 2022; 118:46-56. [PMID: 35305772 DOI: 10.1016/j.jes.2021.08.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/28/2021] [Accepted: 08/29/2021] [Indexed: 06/14/2023]
Abstract
The adsorption behaviors of ciprofloxacin (CIP), a fluoroquinolone antibiotic, onto goethite (Gt) in the presence of silver and titanium dioxide nanoparticles (AgNPs and TiO2NPs) were investigated. Results showed that CIP adsorption kinetics in Gt with or without NPs both followed the pseudo-second-order kinetic model. The presence of AgNPs or TiO2NPs inhibited the adsorption of CIP by Gt. The amount of inhibition of CIP sorption due to AgNPs was decreased with an increase of solution pH from 5.0 to 9.0. In contrast, in the presence of TiO2NPs, CIP adsorption by Gt was almost unchanged at pHs of 5.0∼6.5 but was decreased with an increase of pH from 6.5 to 9.0. The mechanisms of AgNPs and TiO2NPs in inhibiting CIP adsorption by Gt were different, which was attributed to citrate coating of AgNPs resulting in competition with CIP for adsorption sites on Gt, while TiO2NPs could compete with Gt for CIP adsorption. Additionally, CIP was adsorbed by Gt or TiO2NPs through a tridentate complex involving the bidentate inner-sphere coordination of the deprotonated carboxylic group and hydrogen bonding through the adjacent carbonyl group on the quinoline ring. These findings advance our understanding of the environmental behavior and fate of fluoroquinolone antibiotics in the presence of NPs.
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Affiliation(s)
- Jie Tang
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Yun Wang
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Qiang Xue
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China.
| | - Fei Liu
- MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), Beijing 100083, China; Beijing Key Laboratory of Water Resources and Environmental Engineering, School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
| | - Kenneth C Carroll
- Water Science and Management Program, New Mexico State University, MSC 3Q, USA; Plant & Environmental Science, New Mexico State University, Las Cruces, NM 88003, USA
| | - Xiaohua Lu
- National Institute of Metrology, Beijing 100022, China
| | - Taogeng Zhou
- Beijing Institute of Technology, Beijing 100081, China
| | - Dengjun Wang
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, AL 36849, USA
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Jiang W, Xu X, Hall R, Zhang Y, Carroll KC, Ramos F, Engle MA, Lin L, Wang H, Sayer M, Xu P. Datasets associated with the characterization of produced water and Pecos River water in the Permian Basin, the United States. Data Brief 2022; 43:108443. [PMID: 35845093 PMCID: PMC9283875 DOI: 10.1016/j.dib.2022.108443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/28/2022] [Accepted: 06/29/2022] [Indexed: 11/30/2022] Open
Abstract
The data in this report are associated with “Characterization of Produced Water and Surrounding Surface Water in the Permian Basin, the United States” (Jiang et al. 2022) and include raw data on produced water (PW) quality and Pecos River water quality in the Permian Basin, which is one of the major oil and gas producing areas in the U.S. The data include 46 samples for PW and 10 samples for Pecos River water. The data include wet chemistry, mineral salts, metals, oil and grease, volatile and semi-volatile organic compounds, radionuclides, ammonia, hydraulic fracturing additives, and per- and polyfluoroalkyl substances. The PW samples were collected from five different locations in the Permian Basin. Twenty-four of the PW samples and the ten Pecos River samples were analyzed by the authors. The information for the rest of PW samples (22 samples) was provided by industrial collaborators in the Permian Basin. Statistical analyses were performed on the combined data to obtain Mean, Max, Min, 25th percentile, 50th percentile, and 75th percentile of each analyte.
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Affiliation(s)
- Wenbin Jiang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Xuesong Xu
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Ryan Hall
- NGL Partners LP, Santa Fe, NM 87501, United States
| | - Yanyan Zhang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Kenneth C. Carroll
- Department of Plant and Environmental Science, New Mexico State University, Las Cruces, NM, United States
| | - Frank Ramos
- Department of Geological Sciences, New Mexico State University, Las Cruces, NM 88003, United States
| | - Mark A. Engle
- Department of Earth, Environmental and Resource Sciences, The University of Texas at El Paso, El Paso, TX 79968, United States
| | - Lu Lin
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Huiyao Wang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | | | - Pei Xu
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
- Corresponding author.
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10
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Jiang W, Xu X, Hall R, Zhang Y, Carroll KC, Ramos F, Engle MA, Lin L, Wang H, Sayer M, Xu P. Characterization of produced water and surrounding surface water in the Permian Basin, the United States. J Hazard Mater 2022; 430:128409. [PMID: 35149501 DOI: 10.1016/j.jhazmat.2022.128409] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 01/16/2022] [Accepted: 01/29/2022] [Indexed: 06/14/2023]
Abstract
A thorough understanding of produced water (PW) quality is critical to advance the knowledge and tools for effective PW management, treatment, risk assessment, and feasibility for beneficial reuse outside the oil and gas industry. This study provides the first step to better understand PW quality to develop beneficial reuse programs that are protective of human health and the environment. In total, 46 PW samples from unconventional operations in the Permian Basin and ten surface water samples from the Pecos River in New Mexico were collected for quantitative target analyses of more than 300 constituents. Water quality analyses of Pecos River samples could provide context and baseline information for the potential discharge and reuse of treated PW in this area. Temporal PW and river water quality changes were monitored for eight months in 2020. PW samples had total dissolved solids (TDS) concentrations ranging from 100,800-201,500 mg/L. Various mineral salts, metals, oil and grease, volatile and semi-volatile organic compounds, radionuclides, ammonia, hydraulic fracturing additives, and per- and polyfluoroalkyl substances were detected at different concentrations. Chemical characterization of organic compounds found in Pecos River water showed no evidence of PW origin. Isometric log-ratio Na-Cl-Br analysis showed the salinity in the Pecos River samples appeared to be linked to an increase in natural shallow brine inputs. This study outlines baseline analytical information to advance PW research by describing PW and surrounding surface water quality in the Permian Basin that will assist in determining management strategies, treatment methods, potential beneficial reuse applications, and potential environmental impacts specific to intended beneficial use of treated PW.
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Affiliation(s)
- Wenbin Jiang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Xuesong Xu
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Ryan Hall
- NGL Partners LP, Santa Fe, NM 87501, United States
| | - Yanyan Zhang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Kenneth C Carroll
- Department of Plant and Environmental Science, New Mexico State University, Las Cruces, NM, United States
| | - Frank Ramos
- Department of Geological Sciences, New Mexico State University, Las Cruces, NM 88003, United States
| | - Mark A Engle
- Department of Earth, Environmental and Resource Sciences, The University of Texas at El Paso, El Paso, TX 79968, United States
| | - Lu Lin
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | - Huiyao Wang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States
| | | | - Pei Xu
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States.
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11
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Hu L, Jiang W, Xu X, Wang H, Carroll KC, Xu P, Zhang Y. Toxicological characterization of produced water from the Permian Basin. Sci Total Environ 2022; 815:152943. [PMID: 35007582 DOI: 10.1016/j.scitotenv.2022.152943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 12/18/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Produced water (PW) is a hypersaline waste stream generated from the shale oil and gas industry, consisting of numerous anthropogenic and geogenic compounds. Despite prior geochemical characterization, the comprehensive toxicity assessment is lacking for evaluating treatment technologies and the beneficial use of PW. In this study, a suite of in vitro toxicity assays using various aquatic organisms (luminescent bacterium Vibrio fischeri, fish gill cell line RTgill-W1, and microalgae Scenedesmus obliquus) were developed to investigate the toxicological characterizations of PW from the Permian Basin. The exposure to PW, PW inorganic fraction (PW-IF), and PW salt control (PW-SC) at 30-50% dilutions caused significant toxicological effects in all model species, revealing the high salinity was the foremost toxicological driver in PW. In addition, the toxicity level of PW was usually higher than that of PW-IF, suggesting that organic contaminants might also play a critical role in PW toxicity. When comparing the observed toxicity with associated chemical characterizations in different PW samples, strong correlations were found between them since higher concentrations of contaminants could generally result in higher toxicity towards exposed organisms. Furthermore, the toxicity results from the pretreated PW indicated that those in vitro toxicity assays had different sensitives to the chemical components present in PW. As expected, the combination of multiple pretreatments could lead to a more significant decrease in toxicity compared to the single pretreatment since the mixture of contaminants in PW might exhibit synergistic toxicity. Overall, the current work is expected to enhance our understanding of the potential toxicological impacts of PW to aquatic ecosystems and the relationships between the chemical profiles and observed toxicity in PW, which might be conducive to the establishment of monitoring, remediation, treatment, and reuse protocols for PW.
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Affiliation(s)
- Lei Hu
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, USA
| | - Wenbin Jiang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, USA
| | - Xuesong Xu
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, USA
| | - Huiyao Wang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, USA
| | - Kenneth C Carroll
- Department of Plant and Environmental Science, New Mexico State University, Las Cruces, NM 88003, USA
| | - Pei Xu
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, USA
| | - Yanyan Zhang
- Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, USA.
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12
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Huang D, Khan NA, Wang G, Carroll KC, Brusseau ML. The Co-Transport of PFAS and Cr(VI) in porous media. Chemosphere 2022; 286:131834. [PMID: 34392202 PMCID: PMC8634893 DOI: 10.1016/j.chemosphere.2021.131834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/23/2021] [Accepted: 08/05/2021] [Indexed: 05/06/2023]
Abstract
PFAS and Cr are present at some sites as co-contaminants. The objective of this research was to investigate the co-transport behavior of per- and polyfluoroalkyl substances (PFAS) and hexavalent chromium (Cr(VI)) in porous media. Miscible-displacement experiments were conducted using two soils and an aquifer sediment with different geochemical properties. Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were employed as model PFAS. The retardation of PFOS was decreased in the presence of Cr(VI). Conversely, the transport and retardation of PFOA was not affected by the presence of Cr(VI). The reduction of PFOS retardation caused by Cr(VI) is likely due to sorption competition for both organic-carbon and inorganic (metal-oxides and clay minerals) domains. The relative contributions of the three soil constituents to PFOS sorption and the potential for competition between PFOS and Cr(VI) is a function of the geochemical composition of the porous media (i.e., organic carbon, metal-oxides and clay minerals). The PFAS had minimal impact on the retention and transport of Cr(VI). To our knowledge, the results presented herein represent the first reported data for PFOS and Cr(VI) co-transport in porous media. The results of this study indicate that the presence of Cr(VI) has the potential to increase the migration potential of PFOS in soil and groundwater, which should be considered when characterizing electroplating facilities, leather tanning facilities, and other co-contaminated sites.
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Affiliation(s)
- Dandan Huang
- School of Water Resources & Environment, China University of Geosciences (Beijing), Beijing, 100083, PR China; Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States
| | - Naima A Khan
- Department of Plant & Environmental Sciences, New Mexico State University, MSC 3167, Las Cruces, NM, 88003-8001, United States
| | - Guangcai Wang
- School of Water Resources & Environment, China University of Geosciences (Beijing), Beijing, 100083, PR China; MOE Key Laboratory of Groundwater Circulation and Environment Evolution & State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (Beijing), Beijing, 100083, PR China
| | - Kenneth C Carroll
- Department of Plant & Environmental Sciences, New Mexico State University, MSC 3167, Las Cruces, NM, 88003-8001, United States
| | - Mark L Brusseau
- Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States.
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13
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Jiang W, Pokharel B, Lin L, Cao H, Carroll KC, Zhang Y, Galdeano C, Musale DA, Ghurye GL, Xu P. Analysis and prediction of produced water quantity and quality in the Permian Basin using machine learning techniques. Sci Total Environ 2021; 801:149693. [PMID: 34467907 DOI: 10.1016/j.scitotenv.2021.149693] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/11/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Appropriate produced water (PW) management is critical for oil and gas industry. Understanding PW quantity and quality trends for one well or all similar wells in one region would significantly assist operators, regulators, and water treatment/disposal companies in optimizing PW management. In this research, historical PW quantity and quality data in the New Mexico portion (NM) of the Permian Basin from 1995 to 2019 was collected, pre-processed, and analyzed to understand the distribution, trend and characteristics of PW production for potential beneficial use. Various machine learning algorithms were applied to predict PW quantity for different types of oil and gas wells. Both linear and non-linear regression approaches were used to conduct the analysis. The prediction results from five-fold cross-validation showed that the Random Forest Regression model reported high prediction accuracy. The AutoRegressive Integrated Moving Average model showed good results for predicting PW volume in time series. The water quality analysis results showed that the PW samples from the Delaware and Artesia Formations (mostly from conventional wells) had the highest and the lowest average total dissolved solids concentrations of 194,535 mg/L and 100,036 mg/L, respectively. This study is the first research that comprehensively analyzed and predicted PW quantity and quality in the NM-Permian Basin. The results can be used to develop a geospatial metrics analysis or facilitate system modeling to identify the potential opportunities and challenges of PW management alternatives within and outside oil and gas industry. The machine learning techniques developed in this study are generic and can be applied to other basins to predict PW quantity and quality.
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Affiliation(s)
- Wenbin Jiang
- Dept. of Civil Engineering, New Mexico State University, Las Cruces, NM, United States
| | - Beepana Pokharel
- Dept. of Computer Science, New Mexico State University, Las Cruces, NM, United States
| | - Lu Lin
- Dept. of Civil Engineering, New Mexico State University, Las Cruces, NM, United States
| | - Huiping Cao
- Dept. of Computer Science, New Mexico State University, Las Cruces, NM, United States
| | - Kenneth C Carroll
- Dept. of Plant and Environmental Science, New Mexico State University, Las Cruces, NM, United States
| | - Yanyan Zhang
- Dept. of Civil Engineering, New Mexico State University, Las Cruces, NM, United States
| | - Carlos Galdeano
- ExxonMobil Upstream Research Company, Research & Technology Development-Unconventionals, Spring, TX 77389, United States
| | - Deepak A Musale
- ExxonMobil Upstream Research Company, Research & Technology Development-Unconventionals, Spring, TX 77389, United States
| | - Ganesh L Ghurye
- ExxonMobil Upstream Research Company, Research & Technology Development-Unconventionals, Spring, TX 77389, United States
| | - Pei Xu
- Dept. of Civil Engineering, New Mexico State University, Las Cruces, NM, United States.
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Wang Y, Khan N, Huang D, Carroll KC, Brusseau ML. Transport of PFOS in aquifer sediment: Transport behavior and a distributed-sorption model. Sci Total Environ 2021; 779:146444. [PMID: 33740555 PMCID: PMC8565396 DOI: 10.1016/j.scitotenv.2021.146444] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/06/2021] [Accepted: 03/07/2021] [Indexed: 05/22/2023]
Abstract
The objectives of this research were to examine the transport of perfluorooctane sulfonic acid (PFOS) in aquifer sediment comprising different geochemical properties, and to compare the behavior to that observed for PFOS transport in soil and sand. PFOS retardation was relatively low for transport in all aquifer media. The PFOS breakthrough curves were asymmetrical and exhibited extensive concentration tailing, indicating that sorption/desorption was significantly nonideal. The results of model simulations indicated that rate-limited sorption/desorption was the primary cause of the nonideal PFOS transport. Comparison of PFOS transport in aquifer media to data reported for PFOS transport in two soils and a quartz sand showed that PFOS exhibited more extensive elution tailing for the soils, likely reflecting differences in the relative contributions of various media constituents to sorption. A three-component distributed-sorption model was developed that accounted for contributions from soil organic carbon, metal oxides, and silt + clay fraction. The model produced very good predictions of Kd for the five media with lower soil organic‑carbon contents (≤0.1%). Soil organic carbon was estimated to contribute 19-42% of the total sorption for all media except the sand, to which it contributed ~100%. The contribution of silt + clay ranged from 51 to 80% for all media except the sand. The only medium for which the contribution of metal-oxides was significant is Hanford, with an estimated contribution of 15%. Overall, the results of the study indicate that sorption of PFOS by these aquifer media comprised contributions from multiple soil constituents.
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Affiliation(s)
- Yake Wang
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, USA
| | - Naima Khan
- Department of Plant & Environmental Science, New Mexico State University, Las Cruces, NM 88003, USA; Water Science and Management Program, New Mexico State University, Las Cruces, NM 88003, USA
| | - Dandan Huang
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, USA; School of Water Resources & Environment, China University of Geosciences, Beijing 100083, PR China
| | - Kenneth C Carroll
- Department of Plant & Environmental Science, New Mexico State University, Las Cruces, NM 88003, USA; Water Science and Management Program, New Mexico State University, Las Cruces, NM 88003, USA
| | - Mark L Brusseau
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, USA.
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15
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Van Glubt S, Brusseau ML, Yan N, Huang D, Khan N, Carroll KC. Column versus batch methods for measuring PFOS and PFOA sorption to geomedia. Environ Pollut 2021; 268:115917. [PMID: 33143983 PMCID: PMC7746577 DOI: 10.1016/j.envpol.2020.115917] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 10/14/2020] [Accepted: 10/20/2020] [Indexed: 05/22/2023]
Abstract
The objective of this study is to compare the consistency between column and batch experiment methods for measuring solid-phase sorption coefficients and isotherms for per and polyfluoroalkyl substances (PFAS). Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are used as representative PFAS, and experiments are conducted with three natural porous media with differing geochemical properties. Column-derived sorption isotherms are generated by conducting multiple experiments with different input concentrations (multi-C0 method) or employing elution-front integration wherein the entire isotherm is determined from a single breakthrough curve (BTC) elution front. The isotherms generated with the multi-C0 column method compared remarkably well to the batch isotherms over an aqueous concentration range of 3-4 orders of magnitude. Specifically, the 95% confidence intervals for the individual isotherm variables overlapped, producing statistically identical regressions. The elution-front integration isotherms generally agreed with the batch isotherms, but exhibited noise and systematic deviation at lower concentrations in some cases. All data sets were well described by the Freundlich isotherm model. Freundlich N values ranged from 0.75 to 0.81 for PFOS and was 0.87 for PFOA and are consistent with values reported in the literature for different geomedia. The results of this study indicate that column and batch experiments can measure consistent sorption isotherms and sorption coefficients for PFOS and PFOA when robust experimental setup and data analysis are implemented.
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Affiliation(s)
- Sarah Van Glubt
- Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States
| | - Mark L Brusseau
- Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States.
| | - Ni Yan
- Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States; Key Lab of Marine Environmental Science and Ecology, Ministry of Education, College of Environmental Science and Engineering, Ocean University of China, Qingdao, PR China
| | - Dandan Huang
- Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States; School of Water Resources & Environment, China University of Geosciences, Beijing, PR China
| | - Naima Khan
- Department of Plant & Environmental Sciences, New Mexico State University, Las Cruces, NM, United States
| | - Kenneth C Carroll
- Department of Plant & Environmental Sciences, New Mexico State University, Las Cruces, NM, United States
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16
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Khan NA, Carroll KC. Natural attenuation method for contaminant remediation reagent delivery assessment for in situ chemical oxidation using aqueous ozone. Chemosphere 2020; 247:125848. [PMID: 31958648 DOI: 10.1016/j.chemosphere.2020.125848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/18/2019] [Accepted: 01/04/2020] [Indexed: 06/10/2023]
Abstract
A Monitored Natural Attenuation (MNA) assessment approach typically used for contaminant remediation feasibility assessment was developed here for remediation-reagent delivery assessment. Subsurface delivery of oxidants, such as aqueous ozone (O3) for in situ chemical oxidation (ISCO) of groundwater contaminants, is naturally attenuated by oxidant demand and reactivity. We compared mixed reactor kinetic experiments, sand column tracer transport experiments, and reactive transport modeling and assessment methods to quantify natural attenuation kinetics, aqueous O3 solute transport, oxidant demand kinetics, and ISCO reagent delivery limitations. Sorption of aqueous O3 to quartz sand was observed during transport of O3 through water-saturated porous media. Pseudo 1st order decomposition rate constants of O3 bulk attenuation with transport were comparable to mixed reactor experiments without transport, and reactive transport modeling of miscible-displacement column experiments was used to quantify each attenuation process. Aqueous ionic strength was correlated with O3 decomposition rate constants, which was the dominant reagent delivery attenuation process. These results suggest that aqueous O3 decomposition and oxidant delivery attenuation can be predictable upon characterization of the sediment oxidant demand and dispersion, and increasing groundwater velocity during aqueous O3 injection can maximize transport distance for reagent delivery.
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Affiliation(s)
- Naima A Khan
- Water Science and Management Program, New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM, 88003, USA; Plant & Environmental Science, New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM, 88003, USA
| | - Kenneth C Carroll
- Water Science and Management Program, New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM, 88003, USA; Plant & Environmental Science, New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM, 88003, USA.
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17
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Abstract
The objective of this research was to examine the influence of nonideal sorption/desorption on the transport of polyfluorinated alkyl substances (PFASs) in soil, with a specific focus on characterizing and quantifying potential extended, mass-transfer-limited elution behavior. Perfluorooctane sulfonic acid (PFOS) was used as a representative PFAS, and miscible-displacement experiments were conducted with two soils comprising contrasting geochemical properties. The influence of nonlinear, rate-limited, hysteretic, and irreversible sorption/desorption on transport was investigated through experiments and model simulations. The breakthrough curves measured for PFOS transport in the two soils were asymmetrical and exhibited extensive elution tailing, indicating that sorption/desorption was significantly nonideal. The widely used two-domain sorption kinetics model could not fully simulate the observed transport behavior, whereas a multirate model employing a continuous distribution of sorption domains was successful. The overall results indicated that sorption/desorption was significantly rate-limited and that nonlinear, hysteretic, and irreversible sorption/desorption had minimal impact on PFOS transport. Comparison of PFOS transport data to data reported for two hydrophobic organic contaminants (HOCs) showed that the HOCs exhibited much more extensive elution tailing, likely reflecting differences in sorption/desorption mechanisms. The projected influence of rate-limited sorption/desorption on PFOS transport at the field scale was investigated through simulation. The results of the study suggest that rate-limited sorption/desorption may affect the field-scale transport of PFOS and other PFAS for systems influenced by transient or short-residence-time conditions and in some cases could possibly increase the amount of flushing required to reduce PFOS concentrations to levels below those associated with human-health concerns.
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Affiliation(s)
- Mark L. Brusseau
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, United States
- Hydrology and Atmospheric Sciences Department, University of Arizona, Tucson, AZ 85721, United States
- Corresponding author:
| | - Naima Khan
- Department of Plant &Environmental Sciences, New Mexico State University, Las Cruces, New Mexico, United States
| | - Yake Wang
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, United States
| | - Ni Yan
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, United States
- Hydrology and Atmospheric Sciences Department, University of Arizona, Tucson, AZ 85721, United States
| | - Sarah Van Glubt
- Environmental Science Department, University of Arizona, Tucson, AZ 85721, United States
| | - Kenneth C. Carroll
- Department of Plant &Environmental Sciences, New Mexico State University, Las Cruces, New Mexico, United States
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18
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Milavec J, Tick GR, Brusseau ML, Carroll KC. 1,4-Dioxane cosolvency impacts on trichloroethene dissolution and sorption. Environ Pollut 2019; 252:777-783. [PMID: 31200203 PMCID: PMC7039255 DOI: 10.1016/j.envpol.2019.05.156] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 05/28/2019] [Accepted: 05/30/2019] [Indexed: 06/09/2023]
Abstract
Solvent stabilizer 1,4-dioxane, an emerging recalcitrant groundwater contaminant, was commonly added to chlorinated solvents such as trichloroethene (TCE), and the impact of co-disposal on contaminant transport processes remains uncertain. A series of batch equilibrium experiments was conducted with variations of 1,4-dioxane and TCE composition to evaluate aqueous dissolution of the two components and their sorption to aquifer sediments. The solubility of TCE increased with increasing amounts of 1,4-dioxane, indicating that 1,4-dioxane acts as a cosolvent causing solubility enhancement of co-contaminants. The solubilization results compared favorably with predictions using the log-linear cosolvency model. Equilibrium sorption coefficients (Kd and Kf) were also measured for different 1,4-dioxane and TCE compositions, and the findings indicate that both contaminants adsorb to aquifer sediments and TCE Kd values increased with increasing organic matter content. However, the Kd for TCE decreased with increases in 1,4-dioxane concentration, which was attributed to cosolvency impacts on TCE solubility. These findings further advance our understanding of the mass-transfer processes controlling groundwater plumes containing 1,4-dioxane, and also have implications for the remediation of 1,4-dioxane contamination.
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Affiliation(s)
- Justin Milavec
- Water Science and Management Program, New Mexico State University, MSC 3Q, USA; Plant & Environmental Science, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM, 88003, USA
| | - Geoffrey R Tick
- Department of Geological Sciences, University of Alabama, Tuscaloosa, AL, 35487, USA
| | - Mark L Brusseau
- Soil, Water and Environmental Science Department, University of Arizona, USA; Hydrology and Atmospheric Sciences Department, University of Arizona, Tucson, AZ, 85721, USA
| | - Kenneth C Carroll
- Water Science and Management Program, New Mexico State University, MSC 3Q, USA; Plant & Environmental Science, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM, 88003, USA.
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19
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Khan NA, Johnson MD, Kubicki JD, Holguin FO, Dungan B, Carroll KC. Cyclodextrin-enhanced 1,4-dioxane treatment kinetics with TCE and 1,1,1-TCA using aqueous ozone. Chemosphere 2019; 219:335-344. [PMID: 30551099 DOI: 10.1016/j.chemosphere.2018.11.200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 06/09/2023]
Abstract
Enhanced reactivity of aqueous ozone (O3) with hydroxypropyl-β-cyclodextrin (HPβCD) and its impact on relative reactivity of O3 with contaminants were evaluated herein. Oxidation kinetics of 1,4-dioxane, trichloroethylene (TCE), and 1,1,1-trichloroethane (TCA) using O3 in single and multiple contaminant systems, with and without HPβCD, were quantified. 1,4-Dioxane decay rate constants for O3 in the presence of HPβCD increased compared to those without HPβCD. Density functional theory molecular modeling confirmed that formation of ternary complexes with HPβCD, O3, and contaminant increased reactivity by increasing reactant proximity and through additional reactivity within the HPβCD cavity. In the presence of chlorinated co-contaminants, the oxidation rate constant of 1,4-dioxane was enhanced. Use of HPβCD enabled O3 reactivity within the HPβCD cavity and enhanced 1,4-dioxane treatment rates without inhibition in the presence of TCE, TCA, and radical scavengers including NaCl and bicarbonate. Micro-environmental chemistry within HPβCD inclusion cavities mediated contaminant oxidation reactions with increased reaction specificity.
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Affiliation(s)
- Naima A Khan
- Water Science and Management Program, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM 88003, USA; Plant & Environmental Science, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM 88003, USA
| | - Michael D Johnson
- Department of Chemistry and Biochemistry, New Mexico State University, MSC 3C P.O. Box 30001, Las Cruces, NM 88003, USA
| | - James D Kubicki
- Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968-0555, USA
| | - F Omar Holguin
- Plant & Environmental Science, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM 88003, USA
| | - Barry Dungan
- Plant & Environmental Science, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM 88003, USA
| | - Kenneth C Carroll
- Water Science and Management Program, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM 88003, USA; Plant & Environmental Science, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, NM 88003, USA.
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20
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Brusseau ML, Yan N, Van Glubt S, Wang Y, Chen W, Lyu Y, Dungan B, Carroll KC, Holguin FO. Comprehensive retention model for PFAS transport in subsurface systems. Water Res 2019; 148:41-50. [PMID: 30343197 PMCID: PMC6294326 DOI: 10.1016/j.watres.2018.10.035] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/12/2018] [Accepted: 10/12/2018] [Indexed: 05/19/2023]
Abstract
A comprehensive compartment model is presented for PFAS retention that incorporates all potential processes relevant for transport in source zones. Miscible-displacement experiments were conducted to investigate separately the impact of adsorption at the air-water and decane-water interfaces on PFAS retention and transport. Two porous media were used, a quartz sand and a soil, and perfluorooctanesulfonic acid (PFOS) was used as the model PFAS. The breakthrough curves for transport under water-unsaturated conditions were shifted noticeably rightward (delayed arrival) compared to the breakthrough curves for saturated conditions, indicating greater retardation due to adsorption at the air-water or decane-water interface. The retardation factor was 7 for PFOS transport in the sand for the air-water system, compared to 1.8 for saturated conditions. PFOS retardation factors for transport in the soil were 7.3 and 3.6 for unsaturated (air-water) vs saturated conditions. Air-water interfacial adsorption is a significant source of retention for PFOS in these two systems, contributing more than 80% of total retention for the sand and 32% for the soil. For the experiments conducted with decane residual emplaced within the sand, adsorption at the decane-water interface contributed more than 70% to total retention for PFOS transport. Methods to determine or estimate key distribution variables are presented for parameterization of the model. Predicted retardation factors were similar to the measured values, indicating that the conceptual model provided adequate representation of the relevant retention processes and that the parameter estimation methods produced reasonable values. The results of this work indicate that adsorption by fluid-fluid interfaces in variably saturated porous media can be a significant retention process for PFAS that should be considered when characterizing their transport and fate behavior in source zones.
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Affiliation(s)
- Mark L Brusseau
- Soil, Water, and Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States; Hydrology and Atmospheric Sciences Department, University of Arizona, Tucson, AZ, 85721, United States.
| | - Ni Yan
- Hydrology and Atmospheric Sciences Department, University of Arizona, Tucson, AZ, 85721, United States
| | - Sarah Van Glubt
- Soil, Water, and Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States
| | - Yake Wang
- Soil, Water, and Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States
| | - Wei Chen
- Soil, Water, and Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States
| | - Ying Lyu
- Soil, Water, and Environmental Science Department, University of Arizona, Tucson, AZ, 85721, United States; Institute of Water Resources and Environment, Jilin University, Changchun, 130026, PR China
| | - Barry Dungan
- Department of Plant & Environmental Sciences, New Mexico State University, Las Cruces, NM, United States
| | - Kenneth C Carroll
- Department of Plant & Environmental Sciences, New Mexico State University, Las Cruces, NM, United States
| | - F Omar Holguin
- Department of Plant & Environmental Sciences, New Mexico State University, Las Cruces, NM, United States
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21
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Brusseau ML, Carroll KC, Guo Z, Mainhagu J. Borehole Diffusive Flux Apparatus for Characterizing Diffusive Mass-transfer in Subsurface Systems. Environ Earth Sci 2018; 77:648. [PMID: 31435452 PMCID: PMC6703846 DOI: 10.1007/s12665-018-7846-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 09/14/2018] [Indexed: 06/10/2023]
Abstract
The concept of the Borehole Diffusive Flux Apparatus (BDFA) is presented herein. The BDFA is an innovative apparatus designed to provide continuous direct access to an undisturbed column of sediment that can be monitored at multiple discrete vertical intervals to provide high-resolution characterization of local-scale mass transfer and attenuation. The conceptual basis and technical design of the device are presented, along with an example of borehole design and installation at a field site. Mathematical simulations are used to illustrate its application for two scenarios. The results of these simulations indicate that test periods of several weeks to a few months should be sufficient to obtain robust results. The device has the potential to improve our ability to characterize critical mass-transfer and attenuation processes and to quantify the associated rates. This information is key to the evaluation of remediation alternatives, for enhancing the accuracy of mathematical models, and to support more effective long-term management of large groundwater contaminant plumes present at many sites.
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Affiliation(s)
- Mark L Brusseau
- School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721
| | - Kenneth C. Carroll
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM
| | - Zhilin Guo
- School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721
| | - Jon Mainhagu
- School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721
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Khan NA, Johnson MD, Carroll KC. Spectroscopic methods for aqueous cyclodextrin inclusion complex binding measurement for 1,4-dioxane, chlorinated co-contaminants, and ozone. J Contam Hydrol 2018; 210:31-41. [PMID: 29478672 DOI: 10.1016/j.jconhyd.2018.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 01/25/2018] [Accepted: 02/08/2018] [Indexed: 06/08/2023]
Abstract
Recalcitrant organic contaminants, such as 1,4-dioxane, typically require advanced oxidation process (AOP) oxidants, such as ozone (O3), for their complete mineralization during water treatment. Unfortunately, the use of AOPs can be limited by these oxidants' relatively high reactivities and short half-lives. These drawbacks can be minimized by partial encapsulation of the oxidants within a cyclodextrin cavity to form inclusion complexes. We determined the inclusion complexes of O3 and three common co-contaminants (trichloroethene, 1,1,1-trichloroethane, and 1,4-dioxane) as guest compounds within hydroxypropyl-β-cyclodextrin. Both direct (ultraviolet or UV) and competitive (fluorescence changes with 6-p-toluidine-2-naphthalenesulfonic acid as the probe) methods were used, which gave comparable results for the inclusion constants of these species. Impacts of changing pH and NaCl concentrations were also assessed. Binding constants increased with pH and with ionic strength, which was attributed to variations in guest compound solubility. The results illustrate the versatility of cyclodextrins for inclusion complexation with various types of compounds, binding measurement methods are applicable to a wide range of applications, and have implications for both extraction of contaminants and delivery of reagents for treatment of contaminants in wastewater or contaminated groundwater.
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Affiliation(s)
- Naima A Khan
- Water Science and Management, Plant & Environmental Science, New Mexico State University, MSC 3167, P.O. Box 30001, Las Cruces, NM 88003-8001, United States
| | - Michael D Johnson
- Department of Chemistry of and Biochemistry, New Mexico State University, Las Cruces, NM 88003-8003, United States
| | - Kenneth C Carroll
- Water Science and Management, Plant & Environmental Science, New Mexico State University, MSC 3167, P.O. Box 30001, Las Cruces, NM 88003-8001, United States.
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Mateas DJ, Tick GR, Carroll KC. In situ stabilization of NAPL contaminant source-zones as a remediation technique to reduce mass discharge and flux to groundwater. J Contam Hydrol 2017; 204:40-56. [PMID: 28780996 DOI: 10.1016/j.jconhyd.2017.07.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 05/16/2017] [Accepted: 07/24/2017] [Indexed: 06/07/2023]
Abstract
Widely used flushing and in-situ destruction based remediation techniques (i.e. pump-and treat, enhanced-solubilization, and chemical oxidation/reduction) for sites contaminated by nonaqueous phase liquid (NAPL) contaminant sources have been shown to be ineffective at complete mass removal and reducing aqueous-phase contaminant of concern (COC) concentrations to levels suitable for site closure. A remediation method was developed to reduce the aqueous solubility and mass-flux of COCs within NAPL through the in-situ creation of a NAPL mixture source-zone. In contrast to remediation techniques that rely on the rapid removal of contaminant mass, this technique relies on the stabilization of difficult-to-access NAPL sources to reduce COC mass flux to groundwater. A specific amount (volume) of relatively insoluble n-hexadecane (HEXDEC) or vegetable oil (VO) was injected into a trichloroethene (TCE) contaminant source-zone through a bench-scale flow cell port (i.e. well) to form a NAPL mixture of targeted mole fraction (TCE:HEXDEC or TCE:VO). NAPL-aqueous phase batch tests were conducted prior to the flow-cell experiments to evaluate the effects of various NAPL mixture ratios on equilibrium aqueous-phase concentrations of TCE to design optimal NAPL (HEXDEC or VO) injection volumes for the flow-cell experiments. The NAPL-stabilization flow-cell experiments initiated and sustained significant reductions in COC concentration and mass flux due to a combination of both reduced relative permeability (increased NAPL-saturation) and via modification of NAPL composition (decreased TCE mole fraction). Variations in remediation performance (i.e. impacts on TCE concentration and mass flux reduction) between the different HEXDEC injection volumes were relatively minor, and therefore inconsistent with Raoult's Law predictions. This phenomenon likely resulted from non-uniform mixing of the injected HEXDEC with TCE in the source-zone. VO injection caused TCE concentrations and mass-flux to decrease more rapidly than with HEXDEC injections. This phenomenon occurred because the injected VO was observed to mix more uniformly with TCE in the source-zone due to a lower mobilization potential. The relative lower density differences (buoyancy effects) between VO and the flushing solution (water) was the primary factor contributing to the lower mobilization potential for VO. Overall, this study indicated that the delivery of HEXDEC or VO into the toxic TCE source-zone was effective in significantly reducing contaminant aqueous-phase concentration and mass-flux. However, the effectiveness of this in-situ NAPL stabilization technique depends on source delivery, uniform mixing of amendment, and that the amendment remains immobilized within and around the NAPL contaminant source.
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Affiliation(s)
- Douglas J Mateas
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, United States
| | - Geoffrey R Tick
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, United States.
| | - Kenneth C Carroll
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM 88003, United States
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Padgett MC, Tick GR, Carroll KC, Burke WR. Chemical structure influence on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux. J Contam Hydrol 2017; 198:11-23. [PMID: 28202180 DOI: 10.1016/j.jconhyd.2017.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/18/2016] [Accepted: 02/01/2017] [Indexed: 06/06/2023]
Abstract
The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions >0.05 to nonideality as mole fractions decreased. In particular, the TCE generally exhibited more ideal dissolution behavior except at lower mole fractions, and may indicate greater structural/polarity similarity between the two compounds. Raoult's Law and UNIFAC generally under-predicted the batch experiment results for TOL:HEXDEC mixtures especially for mole fractions ≤0.05. The dissolution rate coefficients were similar for both TOL and TCE over all mole fractions tested. Mass flux reduction (MFR) analysis showed that more efficient removal behavior occurred for TOL and TCE with larger mole fractions compared to the lower initial mole fraction mixtures (i.e. <0.2). However, compared to TOL, TCE generally exhibited more efficient removal behavior over all mole fractions tested and may have been the result of structural and molecular property differences between the compounds. Activity coefficient variability as a function of mole fraction was quantified through regression analysis and incorporated into dissolution modeling analyses for the dynamic flushing experiments. TOL elution concentrations were modeled (predicted) reasonable well using ideal and equilibrium assumptions, but the TCE elution concentrations could not be predicted using the ideal model. Rather, the dissolution modeling demonstrated that TCE elution was better described by the nonideal model whereby NAPL-phase activity coefficient varied as a function of COC mole fraction. For dynamic column flushing experiments, dissolution rate kinetics can vary significantly with changes in NAPL volume and surface area. However, under conditions whereby NAPL volume and area are not significantly altered during dissolution, mixture nonideality effects may have a greater relative control on dissolution (elution) and MFR behavior compared to kinetic rate limitations.
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Affiliation(s)
- Mark C Padgett
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, United States
| | - Geoffrey R Tick
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, United States.
| | - Kenneth C Carroll
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, NM 88003, United States
| | - William R Burke
- Department of Geological Sciences, The University of Alabama, Tuscaloosa, AL 35487, United States
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Brusseau ML, Mainhagu J, Morrison C, Carroll KC. Corrigendum to "The vapor-phase multi-stage CMD test for characterizing contaminant mass discharge associated with VOC sources in the vadose zone: Application to three sites in different lifecycle stages of SVE operations" [J. Contam. Hydrol. 179 (2015) 55-64]. J Contam Hydrol 2017; 196:62. [PMID: 27986308 DOI: 10.1016/j.jconhyd.2016.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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Dettmer A, Ball R, Boving TB, Khan NA, Schaub T, Sudasinghe N, Fernandez CA, Carroll KC. Stabilization and prolonged reactivity of aqueous-phase ozone with cyclodextrin. J Contam Hydrol 2017; 196:1-9. [PMID: 27993469 DOI: 10.1016/j.jconhyd.2016.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 11/15/2016] [Accepted: 11/27/2016] [Indexed: 06/06/2023]
Abstract
Recalcitrant organic groundwater contaminants, such as 1,4-dioxane, may require strong oxidants for complete mineralization. However, their efficacy for in-situ chemical oxidation (ISCO) is limited by oxidant decay and reactivity. Hydroxypropyl-β-cyclodextrin (HPβCD) was examined for its ability to stabilize aqueous-phase ozone (O3) and prolong oxidation potential through inclusion complex formation. Partial transformation of HPβCD by O3 was observed. However, HPβCD proved to be sufficiently recalcitrant, because it was only partially degraded in the presence of O3. The formation of a HPβCD:O3 clathrate complex was observed, which stabilized decay of O3. The presence of HPβCD increased the O3 half-life linearly with increasing HPβCD:O3 molar ratio. The O3 half-life in solutions increased by as much as 40-fold relative to HPβCD-free O3 solutions. Observed O3 release from HPβCD and indigo oxidation confirmed that the formation of the inclusion complex is reversible. This proof-of-concept study demonstrates that HPβCD can complex O3 while preserving its reactivity. These results suggest that the use of clathrate stabilizers, such as HPβCD, can support the development of a facilitated-transport enabled ISCO for the O3 treatment of groundwater contaminated with recalcitrant compounds.
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Affiliation(s)
- Adam Dettmer
- New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM 88003, USA
| | - Raymond Ball
- Enchem Engineering, Inc., 151 California Street, Newton, MA 02458, USA
| | | | - Naima A Khan
- New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM 88003, USA
| | - Tanner Schaub
- New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM 88003, USA
| | - Nilusha Sudasinghe
- New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM 88003, USA
| | | | - Kenneth C Carroll
- New Mexico State University, MSC 3Q, P.O. Box 30003, Las Cruces, NM 88003, USA.
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Chen H, Carroll KC. Metal-free catalysis of persulfate activation and organic-pollutant degradation by nitrogen-doped graphene and aminated graphene. Environ Pollut 2016; 215:96-102. [PMID: 27179328 DOI: 10.1016/j.envpol.2016.04.088] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 03/29/2016] [Accepted: 04/25/2016] [Indexed: 06/05/2023]
Abstract
We evaluated three types of functionalized, graphene-based materials for activating persulfate (PS) and removing (i.e., sorption and oxidation) sulfamethoxazole (SMX) as a model emerging contaminant. Although advanced oxidative water treatment requires PS activation, activation requires energy or chemical inputs, and toxic substances are contained in many catalysts. Graphene-based materials were examined herein as an alternative to metal-based catalysts. Results show that nitrogen-doped graphene (N-GP) and aminated graphene (NH2-GP) can effectively activate PS. Overall, PS activation by graphene oxide was not observed in this study. N-GP (50 mg L(-1)) can rapidly activate PS (1 mM) to remove >99.9% SMX within 3 h, and NH2-GP (50 mg L(-1)) activated PS (1 mM) can also remove 50% SMX within 10 h. SMX sorption and total removal was greater for N-GP, which suggests oxidation was enhanced by increasing proximity to PS activation sites. Increasing pH enhanced the N-GP catalytic ability, and >99.9% SMX removal time decreased from 3 h to 1 h when pH increased from 3 to 9. However, the PS catalytic ability was inhibited at pH 9 for NH2-GP. Increases in ionic strength (100 mM NaCl or Na2SO4) and addition of radical scavengers (500 mM ethanol) both had negligible impacts on SMX removal. With bicarbonate addition (100 mM), while the catalytic ability of N-GP remained unaltered, NH2-GP catalytic ability was inhibited completely. Humic acid (250 mg L(-1)) was partially effective in inhibiting SMX removal in both N-GP and NH2-GP systems. These results have implications for elucidating oxidant catalysis mechanisms, and they quantify the ability of functionalization of graphene with hetero-atom doping to effectively catalyze PS for water treatment of organic pollutants including emerging contaminants.
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Affiliation(s)
- Hao Chen
- Department of Plant and Environmental Sciences, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, N.M., 88003-8003, United States
| | - Kenneth C Carroll
- Department of Plant and Environmental Sciences, New Mexico State University, MSC 3Q P.O. Box 30003, Las Cruces, N.M., 88003-8003, United States.
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McDonald K, Carroll KC, Brusseau ML. Comparison of Fluid-Fluid Interfacial Areas Measured with X-ray Microtomography and Interfacial Partitioning Tracer Tests for the same Samples. Water Resour Res 2016; 52:5393-5399. [PMID: 28936003 PMCID: PMC5603264 DOI: 10.1002/2016wr018775] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Two different methods are currently used for measuring interfacial areas between immiscible fluids within 3-D porous media, high-resolution microtomographic imaging and interfacial partitioning tracer tests (IPTT). Both methods were used in this study to measure non-wetting/wetting interfacial areas for a natural sand. The microtomographic imaging was conducted on the same packed columns that were used for the IPTTs. This is in contrast to prior studies comparing the two methods, for which in all cases different samples were used for the two methods. In addition, the columns were imaged before and after the IPTTs to evaluate the potential impacts of the tracer solution on fluid configuration and attendant interfacial area. The interfacial areas measured using IPTT are ~5 times larger than the microtomographic-measured values, which is consistent with previous work. Analysis of the image data revealed no significant impact of the tracer solution on NAPL configuration or interfacial area. Other potential sources of error were evaluated, and all were demonstrated to be insignificant. The disparity in measured interfacial areas between the two methods is attributed to the limitation of the microtomography method to characterize interfacial area associated with microscopic surface roughness due to resolution constraints.
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Affiliation(s)
- Kieran McDonald
- Soil, Water, and Environmental Science Dept., University of Arizona
| | | | - Mark L. Brusseau
- Soil, Water, and Environmental Science Dept., University of Arizona
- Hydrology and Water Resources Dept., University of Arizona
- Corresponding Author:
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29
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Khan NA, Engle M, Dungan B, Holguin FO, Xu P, Carroll KC. Volatile-organic molecular characterization of shale-oil produced water from the Permian Basin. Chemosphere 2016; 148:126-36. [PMID: 26802271 DOI: 10.1016/j.chemosphere.2015.12.116] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/23/2015] [Accepted: 12/27/2015] [Indexed: 05/24/2023]
Abstract
Growth in unconventional oil and gas has spurred concerns on environmental impact and interest in beneficial uses of produced water (PW), especially in arid regions such as the Permian Basin, the largest U.S. tight-oil producer. To evaluate environmental impact, treatment, and reuse potential, there is a need to characterize the compositional variability of PW. Although hydraulic fracturing has caused a significant increase in shale-oil production, there are no high-resolution organic composition data for the shale-oil PW from the Permian Basin or other shale-oil plays (Eagle Ford, Bakken, etc.). PW was collected from shale-oil wells in the Midland sub-basin of the Permian Basin. Molecular characterization was conducted using high-resolution solid phase micro extraction gas chromatography time-of-flight mass spectrometry. Approximately 1400 compounds were identified, and 327 compounds had a >70% library match. PW contained alkane, cyclohexane, cyclopentane, BTEX (benzene, toluene, ethylbenzene, and xylene), alkyl benzenes, propyl-benzene, and naphthalene. PW also contained heteroatomic compounds containing nitrogen, oxygen, and sulfur. 3D van Krevelen and double bond equivalence versus carbon number analyses were used to evaluate molecular variability. Source composition, as well as solubility, controlled the distribution of volatile compounds found in shale-oil PW. The salinity also increased with depth, ranging from 105 to 162 g/L total dissolved solids. These data fill a gap for shale-oil PW composition, the associated petroleomics plots provide a fingerprinting framework, and the results for the Permian shale-oil PW suggest that partial treatment of suspended solids and organics would support some beneficial uses such as onsite reuse and bio-energy production.
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Affiliation(s)
- Naima A Khan
- New Mexico State University, Las Cruces, NM, USA
| | - Mark Engle
- U.S. Geological Survey, El Paso, TX, USA
| | - Barry Dungan
- New Mexico State University, Las Cruces, NM, USA
| | | | - Pei Xu
- New Mexico State University, Las Cruces, NM, USA
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Carroll KC, McDonald K, Marble J, Russo AE, Brusseau ML. The impact of transitions between two-fluid and three-fluidphases on fluid configuration and fluid-fluid interfacial areain porous media. Water Resour Res 2015; 51:7189-7201. [PMID: 27350722 PMCID: PMC4919665 DOI: 10.1002/2015wr017490] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Multiphase-fluid distribution and flow is inherent in numerous areas of hydrology. Yet, pore-scale characterization of transitions between two and three immiscible-fluids is limited. The objective of this study was to examine the impact of such transitions on the pore-scale configuration of organic liquid in a multi-fluid system comprising natural porous media. Three-dimensional images of an organic liquid (trichloroethene) in two-phase (organic-liquid/water) and three-phase (air/organic-liquid/water) systems were obtained using X-ray microtomography before and after drainage and imbibition. Upon transition from a two-phase to a three-phase system, a significant portion of the organic liquid (intermediate wetting fluid) was observed to exist as lenses and films in contact with air (nonwetting fluid). In these cases, the air was either encased by or contiguous to the organic liquid. The presence of air resulted in an increase in the surface-area-to-volume ratios for the organic-liquid blobs. Upon imbibition, the air was displaced downgradient, and concomitantly, the morphology of the organic-liquid blobs no longer in contact with air reverted to that characteristic of a two-phase distribution (i.e., more spherical blobs and ganglia). This change in morphology resulted in a reduction in the surface-area-to-volume ratio. These results illustrate the impact of transitions between two-phase and three-phase conditions on fluid configuration, and they demonstrate the malleable nature of fluid configuration under dynamic, multiphase-flow conditions. The results have implications for characterizing and modeling pore-scale flow and mass-transfer processes.
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Affiliation(s)
| | - Kieran McDonald
- Soil, Water and Environmental Science Department, School of Earth
and Environmental Sciences, University of Arizona, 429 Shantz Bldg., Tucson, AZ
85721
| | - Justin Marble
- Soil and Groundwater Office, Department of Energy, Wash., DC
| | - Ann E. Russo
- Soil, Water and Environmental Science Department, School of Earth
and Environmental Sciences, University of Arizona, 429 Shantz Bldg., Tucson, AZ
85721
| | - Mark L. Brusseau
- Soil, Water and Environmental Science Department, School of Earth
and Environmental Sciences, University of Arizona, 429 Shantz Bldg., Tucson, AZ
85721
- Hydrology and Water Resources Department, School of Earth and
Environmental Sciences, University of Arizona, 429 Shantz Bldg., Tucson, AZ
85721
- Corresponding author:
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Brusseau ML, Mainhagu J, Morrison C, Carroll KC. The vapor-phase multi-stage CMD test for characterizing contaminant mass discharge associated with VOC sources in the vadose zone: Application to three sites in different lifecycle stages of SVE operations. J Contam Hydrol 2015; 179:55-64. [PMID: 26047819 PMCID: PMC4520789 DOI: 10.1016/j.jconhyd.2015.05.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/10/2015] [Accepted: 05/17/2015] [Indexed: 06/01/2023]
Abstract
Vapor-phase multi-stage contaminant mass discharge (CMD) tests were conducted at three field sites to measure mass discharge associated with contaminant sources located in the vadose zone. The three sites represent the three primary stages of the soil vapor extraction (SVE) operations lifecycle-pre/initial-SVE, mid-lifecycle, and near-closure. A CMD of 32g/d was obtained for a site at which soil vapor SVE has been in operation for approximately 6years, and for which mass removal is currently in the asymptotic stage. The contaminant removal behavior exhibited for the vapor extractions conducted at this site suggests that there is unlikely to be a significant mass of non-vapor-phase contaminant (e.g., DNAPL, sorbed phase) remaining in the advective domains, and that most remaining mass is likely located in poorly accessible domains. Given the conditions for this site, this remaining mass is hypothesized to be associated with the low-permeability (and higher water saturation) region in the vicinity of the saturated zone and capillary fringe. A CMD of 25g/d was obtained for a site wherein SVE has been in operation for several years but concentrations and mass-removal rates are still relatively high. A CMD of 270g/d was obtained for a site for which there were no prior SVE operations. The behavior exhibited for the vapor extractions conducted at this site suggest that non-vapor-phase contaminant mass (e.g., DNAPL) may be present in the advective domains. Hence, the asymptotic conditions observed for this site most likely derive from a combination of rate-limited mass transfer from DNAPL (and sorbed) phases present in the advective domain as well as mass residing in lower-permeability ("non-advective") regions. The CMD values obtained from the tests were used in conjunction with a recently developed vapor-discharge tool to evaluate the impact of the measured CMDs on groundwater quality.
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Affiliation(s)
- M L Brusseau
- Soil, Water and Environmental Science Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721, United States; Hydrology and Water Resources Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721, United States.
| | - J Mainhagu
- Soil, Water and Environmental Science Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721, United States
| | - C Morrison
- Soil, Water and Environmental Science Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721, United States
| | - K C Carroll
- Plant and Environmental Sciences Department, New Mexico State University, United States
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Scheibe TD, Murphy EM, Chen X, Rice AK, Carroll KC, Palmer BJ, Tartakovsky AM, Battiato I, Wood BD. An analysis platform for multiscale hydrogeologic modeling with emphasis on hybrid multiscale methods. Ground Water 2015; 53:38-56. [PMID: 24628122 DOI: 10.1111/gwat.12179] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 01/23/2014] [Indexed: 06/03/2023]
Abstract
One of the most significant challenges faced by hydrogeologic modelers is the disparity between the spatial and temporal scales at which fundamental flow, transport, and reaction processes can best be understood and quantified (e.g., microscopic to pore scales and seconds to days) and at which practical model predictions are needed (e.g., plume to aquifer scales and years to centuries). While the multiscale nature of hydrogeologic problems is widely recognized, technological limitations in computation and characterization restrict most practical modeling efforts to fairly coarse representations of heterogeneous properties and processes. For some modern problems, the necessary level of simplification is such that model parameters may lose physical meaning and model predictive ability is questionable for any conditions other than those to which the model was calibrated. Recently, there has been broad interest across a wide range of scientific and engineering disciplines in simulation approaches that more rigorously account for the multiscale nature of systems of interest. In this article, we review a number of such approaches and propose a classification scheme for defining different types of multiscale simulation methods and those classes of problems to which they are most applicable. Our classification scheme is presented in terms of a flowchart (Multiscale Analysis Platform), and defines several different motifs of multiscale simulation. Within each motif, the member methods are reviewed and example applications are discussed. We focus attention on hybrid multiscale methods, in which two or more models with different physics described at fundamentally different scales are directly coupled within a single simulation. Very recently these methods have begun to be applied to groundwater flow and transport simulations, and we discuss these applications in the context of our classification scheme. As computational and characterization capabilities continue to improve, we envision that hybrid multiscale modeling will become more common and also a viable alternative to conventional single-scale models in the near future.
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Affiliation(s)
- Timothy D Scheibe
- Pacific Northwest National Laboratory, PO Box 999,MS K9-36, Richland, WA 99352
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Miao Z, Carreón-Diazconti C, Carroll KC, Brusseau ML. The impact of biostimulation on the fate of sulfate and associated sulfur dynamics in groundwater. J Contam Hydrol 2014; 164:240-250. [PMID: 25016586 PMCID: PMC4136432 DOI: 10.1016/j.jconhyd.2014.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 06/16/2014] [Accepted: 06/20/2014] [Indexed: 06/03/2023]
Abstract
The impact of electron-donor addition on sulfur dynamics for a groundwater system with low levels of metal contaminants was evaluated with a pilot-scale biostimulation test conducted at a former uranium mining site. Geochemical and stable-isotope data collected before, during, and after the test were analyzed to evaluate the sustainability of sulfate reducing conditions induced by the test, the fate of hydrogen sulfide, and the impact on aqueous geochemical conditions. The results of site characterization activities conducted prior to the test indicated the absence of measurable bacterial sulfate reduction. The injection of an electron donor (ethanol) induced bacterial sulfate reduction, as confirmed by an exponential decrease of sulfate concentration in concert with changes in oxidation-reduction potential, redox species, alkalinity, production of hydrogen sulfide, and fractionation of δ(34)S-sulfate. High, stoichiometrically-equivalent hydrogen sulfide concentrations were not observed until several months after the start of the test. It is hypothesized that hydrogen sulfide produced from sulfate reduction was initially sequestered in the form of iron sulfides until the exhaustion of readily reducible iron oxides within the sediment. The fractionation of δ(34)S for sulfate was atypical, wherein the enrichment declined in the latter half of the experiment. It was conjectured that mixing effects associated with the release of sulfate from sulfate minerals associated with the sediments, along with possible sulfide re-oxidation contributed to this behavior. The results of this study illustrate the biogeochemical complexity that is associated with in-situ biostimulation processes involving bacterial sulfate reduction.
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Affiliation(s)
- Ziheng Miao
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, AZ, USA; Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, AZ, USA
| | | | | | - Mark L Brusseau
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, AZ, USA; Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, AZ, USA.
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Miao Z, Carroll KC, Brusseau ML. Characterization and quantification of groundwater sulfate sources at a mining site in an arid climate: The Monument Valley site in Arizona, USA. J Hydrol (Amst) 2013; 504:207-215. [PMID: 24729633 PMCID: PMC3980666 DOI: 10.1016/j.jhydrol.2013.09.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The Monument Valley site, a former uranium mining site located in the state of Arizona in the Southwest USA, has high concentrations of sulfate in groundwater. Stable isotope analysis of S and O for sulfate, in combination with geochemical and hydrogeological data, was used to characterize the sources and fate of sulfate. The results indicate the existence of two discrete sources of sulfate (in excess of baseline levels): sulfuric acid released during ore processing and sulfate generated via sulfide-mineral oxidation. The contributions of the sources are related to spatial distributions of sulfate in the plume through analysis of groundwater travel times. Quantification of the sources using two isotope-analysis methods yielded similar results. The results indicate that sulfuric acid served as the primary source (mean = 427 mg/L, 74%), with sulfide-mineral oxidation providing a smaller contribution (mean = 147 mg/L, 26%). It appears that the major contribution to the sulfide-mineral oxidation component originates from oxidation of sulfide minerals in exposed bedrock residing in the primary recharge zone of the local aquifer, which provides an elevated sulfate background for groundwater. Conversely, the oxidation of sulfide minerals associated with the mine tailings appears to provide a relatively minor contribution (∼8% of the overall total). Interestingly, it appears that sulfuric acid served as a sustained source of sulfate for approximately 40 years. This may be related to the accumulation of sulfate salts (formed after neutralization and disposal of the sulfuric acid) in the source zone due to the arid climate of the site. Contrary to the typical assumption applied at many mining sites that sulfide-mineral oxidation is the primary source of sulfate, these sulfate salts are hypothesized to be the primary source for this site.
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Affiliation(s)
- Ziheng Miao
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, AZ, USA
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, AZ, USA
| | | | - Mark L. Brusseau
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, AZ, USA
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, AZ, USA
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Brusseau ML, Carroll KC, Truex MJ, Becker DJ. Characterization and Remediation of Chlorinated Volatile Organic Contaminants in the Vadose Zone: An Overview of Issues and Approaches. Vadose Zone J 2013; 12:10.2136/vzj2012.0137. [PMID: 25383058 PMCID: PMC4222060 DOI: 10.2136/vzj2012.0137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Indexed: 05/25/2023]
Abstract
Contamination of vadose-zone systems by chlorinated solvents is widespread, and poses significant potential risk to human health through impacts on groundwater quality and vapor intrusion. Soil vapor extraction (SVE) is the presumptive remedy for such contamination, and has been used successfully for innumerable sites. However, SVE operations typically exhibit reduced mass-removal effectiveness at some point due to the impact of poorly accessible contaminant mass and associated mass-transfer limitations. Assessment of SVE performance and closure is currently based on characterizing contaminant mass discharge associated with the vadose-zone source, and its impact on groundwater or vapor intrusion. These issues are addressed in this overview, with a focus on summarizing recent advances in our understanding of the transport, characterization, and remediation of chlorinated solvents in the vadose zone. The evolution of contaminant distribution over time and the associated impacts on remediation efficiency will be discussed, as will the potential impact of persistent sources on groundwater quality and vapor intrusion. In addition, alternative methods for site characterization and remediation will be addressed.
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Affiliation(s)
- Mark L. Brusseau
- School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ
| | | | | | - David J. Becker
- U.S. Army Corps of Engineers, Environmental and Munitions Center of Expertise, Omaha, NE
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Brusseau ML, Matthieu DE, Carroll KC, Mainhagu J, Morrison C, McMillan A, Russo A, Plaschke M. Characterizing long-term contaminant mass discharge and the relationship between reductions in discharge and reductions in mass for DNAPL source areas. J Contam Hydrol 2013; 149:1-12. [PMID: 23528743 PMCID: PMC3875322 DOI: 10.1016/j.jconhyd.2013.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Revised: 11/09/2012] [Accepted: 02/25/2013] [Indexed: 05/03/2023]
Abstract
The objective of this study was to characterize the temporal behavior of contaminant mass discharge, and the relationship between reductions in contaminant mass discharge and reductions in contaminant mass, for a very heterogeneous, highly contaminated source-zone field site. Trichloroethene is the primary contaminant of concern, and several lines of evidence indicate the presence of organic liquid in the subsurface. The site is undergoing groundwater extraction for source control, and contaminant mass discharge has been monitored since system startup. The results show a significant reduction in contaminant mass discharge with time, decreasing from approximately 1 to 0.15 kg/d over five years. Two methods were used to estimate the mass of contaminant present in the source area at the initiation of the remediation project. One was based on a comparison of two sets of core data, collected 3.5 years apart, which suggests that a significant (~80%) reduction in aggregate sediment-phase TCE concentrations occurred between sampling events. The second method was based on fitting the temporal contaminant mass discharge data with a simple exponential source-depletion function. Relatively similar estimates, 784 and 993 kg, respectively, were obtained with the two methods. These data were used to characterize the relationship between reductions in contaminant mass discharge (CMDR) and reductions in contaminant mass (MR). The observed curvilinear relationship exhibits a reduction in contaminant mass discharge essentially immediately upon the initiation of mass reduction. This behavior is consistent with a system wherein significant quantities of mass are present in hydraulically poorly accessible domains for which mass removal is influenced by rate-limited mass transfer. The results obtained from the present study are compared to those obtained from other field studies to evaluate the impact of system properties and conditions on mass-discharge and mass-removal behavior. The results indicate that factors such as domain scale, hydraulic-gradient status (induced or natural), and flushing-solution composition had insignificant impact on the CMDR-MR profiles and thus on underlying mass-removal behavior. Conversely, source-zone age, through its impact on contaminant distribution and accessibility, was implicated as a critical factor influencing the nature of the CMDR-MR relationship.
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Affiliation(s)
- M L Brusseau
- Soil, Water and Environmental Science Department, School of Earth and Environmental Sciences, University of Arizona, 429 Shantz Bldg., Tucson, AZ 85721, USA.
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Tan KE, Ellis BC, Lee R, Stamper PD, Zhang SX, Carroll KC. Prospective evaluation of a matrix-assisted laser desorption ionization-time of flight mass spectrometry system in a hospital clinical microbiology laboratory for identification of bacteria and yeasts: a bench-by-bench study for assessing the impact on time to identification and cost-effectiveness. J Clin Microbiol 2012; 50:3301-8. [PMID: 22855510 PMCID: PMC3457442 DOI: 10.1128/jcm.01405-12] [Citation(s) in RCA: 247] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 07/24/2012] [Indexed: 11/20/2022] Open
Abstract
Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been found to be an accurate, rapid, and inexpensive method for the identification of bacteria and yeasts. Previous evaluations have compared the accuracy, time to identification, and costs of the MALDI-TOF MS method against standard identification systems or commercial panels. In this prospective study, we compared a protocol incorporating MALDI-TOF MS (MALDI protocol) with the current standard identification protocols (standard protocol) to determine the performance in actual practice using a specimen-based, bench-by-bench approach. The potential impact on time to identification (TTI) and costs had MALDI-TOF MS been the first-line identification method was quantitated. The MALDI protocol includes supplementary tests, notably for Streptococcus pneumoniae and Shigella, and indications for repeat MALDI-TOF MS attempts, often not measured in previous studies. A total of 952 isolates (824 bacterial isolates and 128 yeast isolates) recovered from 2,214 specimens were assessed using the MALDI protocol. Compared with standard protocols, the MALDI protocol provided identifications 1.45 days earlier on average (P < 0.001). In our laboratory, we anticipate that the incorporation of the MALDI protocol can reduce reagent and labor costs of identification by $102,424 or 56.9% within 12 months. The model included the fixed annual costs of the MALDI-TOF MS, such as the cost of protein standards and instrument maintenance, and the annual prevalence of organisms encountered in our laboratory. This comprehensive cost analysis model can be generalized to other moderate- to high-volume laboratories.
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Affiliation(s)
- K E Tan
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Miao Z, Brusseau ML, Carroll KC, Carreón-Diazconti C, Johnson B. Sulfate reduction in groundwater: characterization and applications for remediation. Environ Geochem Health 2012. [PMID: 21947714 DOI: 10.1007/s1065301194231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Sulfate is ubiquitous in groundwater, with both natural and anthropogenic sources. Sulfate reduction reactions play a significant role in mediating redox conditions and biogeochemical processes for subsurface systems. They also serve as the basis for innovative in situ methods for groundwater remediation. An overview of sulfate reduction in subsurface environments is provided, along with a brief discussion of characterization methods and applications for addressing acid mine drainage. We then focus on two innovative, in situ methods for remediating sulfate-contaminated groundwater, the use of zero-valent iron and the addition of electron-donor substrates. The advantages and limitations associated with the methods are discussed, with examples of prior applications.
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Affiliation(s)
- Z Miao
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, PO Box 210038, Tucson, AZ, USA
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Carroll KC, Oostrom M, Truex MJ, Rohay VJ, Brusseau ML. Assessing performance and closure for soil vapor extraction: integrating vapor discharge and impact to groundwater quality. J Contam Hydrol 2012; 128:71-82. [PMID: 22192346 DOI: 10.1016/j.jconhyd.2011.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 09/22/2011] [Accepted: 10/04/2011] [Indexed: 05/31/2023]
Abstract
Soil vapor extraction (SVE) is typically effective for removal of volatile contaminants from higher-permeability portions of the vadose zone. However, contamination in lower-permeability zones can persist due to mass transfer processes that limit the removal effectiveness. After SVE has been operated for a period of time and the remaining contamination is primarily located in lower-permeability zones, the remedy performance needs to be evaluated to determine whether the SVE system should be optimized, terminated, or transitioned to another technology to replace or augment SVE. Numerical modeling of vapor-phase contaminant transport was used to investigate the correlation between measured vapor-phase mass discharge, MF(r), from a persistent, vadose-zone contaminant source and the resulting groundwater contaminant concentrations. This relationship was shown to be linear, and was used to directly assess SVE remediation progress over time and to determine the level of remediation in the vadose zone necessary to protect groundwater. Although site properties and source characteristics must be specified to establish a unique relation between MF(r) and the groundwater contaminant concentration, this correlation provides insight into SVE performance and support for decisions to optimize or terminate the SVE operation or to transition to another type of treatment.
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Brusseau ML, Carroll KC, Allen T, Baker J, Diguiseppi W, Hatton J, Morrison C, Russo A, Berkompas J. Impact of in situ chemical oxidation on contaminant mass discharge: linking source-zone and plume-scale characterizations of remediation performance. Environ Sci Technol 2011; 45:5352-8. [PMID: 21615133 PMCID: PMC3157310 DOI: 10.1021/es200716s] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A large-scale permanganate-based in situ chemical oxidation (ISCO) effort has been conducted over the past ten years at a federal Superfund site in Tucson, AZ, for which trichloroethene (TCE) is the primary contaminant of concern. Remediation performance was assessed by examining the impact of treatment on contaminant mass discharge, an approach that has been used for only a very few prior ISCO projects. Contaminant mass discharge tests were conducted before and after permanganate injection to measure the impact at the source-zone scale. The results indicate that ISCO caused a significant reduction in mass discharge (approximately 75%). The standard approach of characterizing discharge at the source-zone scale was supplemented with additional characterization at the plume scale, which was evaluated by examining the change in contaminant mass discharge associated with the pump-and-treat system. The integrated contaminant mass discharge decreased by approximately 70%, consistent with the source-zone-scale measurements. The integrated mass discharge rebounded from 0.1 to 0.2 kg/d within one year after cessation of permanganate injections, after which it has been stable for several years. Collection of the integrated contaminant mass discharge data throughout the ISCO treatment period provided a high-resolution, real-time analysis of the site-wide impact of ISCO, thereby linking source-zone remediation to impacts on overall risk. The results indicate that ISCO was successful in reducing contaminant mass discharge at this site, which comprises a highly heterogeneous subsurface environment. Analysis of TCE sediment concentration data for core material collected before and after ISCO supports the hypothesis that the remaining mass discharge is associated in part with poorly accessible contaminant mass residing within lower-permeability zones.
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Affiliation(s)
- M L Brusseau
- School of Earth and Environmental Sciences, University of Arizona, Tucson, Arizona, USA.
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Durand CM, Alonso CD, Subhawong AP, Kwiatkowski NP, Showel M, Carroll KC, Marr KA. Rapidly progressive cutaneous Rhizopus microsporus infection presenting as Fournier's gangrene in a patient with acute myelogenous leukemia. Transpl Infect Dis 2011; 13:392-6. [PMID: 21443549 DOI: 10.1111/j.1399-3062.2011.00601.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Members of the genus Rhizopus within the class Zygomycetes can cause devastating opportunistic infections. Cutaneous disease arising from direct inoculation of fungal spores has the potential to disseminate widely. Here, we describe a dramatic case of cutaneous Rhizopus infection involving the penis in a patient with acute myelogenous leukemia. Despite aggressive surgical debridement, systemic antifungal therapy, and donor lymphocyte infusion, the infection was ultimately fatal. This case illustrates the unique diagnostic and therapeutic challenges in the clinical management of cutaneous Rhizopus infection.
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Affiliation(s)
- C M Durand
- Division of Infectious Diseases, Johns Hopkins University, Baltimore, Maryland 21205, USA
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Marble JC, Carroll KC, Janousek H, Brusseau ML. In situ oxidation and associated mass-flux-reduction/mass-removal behavior for systems with organic liquid located in lower-permeability sediments. J Contam Hydrol 2010; 117:82-93. [PMID: 20685008 PMCID: PMC2957374 DOI: 10.1016/j.jconhyd.2010.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 07/02/2010] [Accepted: 07/11/2010] [Indexed: 05/19/2023]
Abstract
The effectiveness of permanganate for in situ chemical oxidation of organic liquid (trichloroethene) trapped in lower-permeability (K) zones located within a higher-permeability matrix was examined in a series of flow-cell experiments. The permanganate solution was applied in both continuous and pulsed-injection modes. Manganese-oxide precipitation, as confirmed by use of SEM-EDS, occurred within, adjacent to, and downgradient of the lower-K zones, reflective of trichloroethene oxidation. During flow interruptions, precipitate formed within the surrounding higher-permeability matrix, indicating diffusive flux of aqueous-phase trichloroethene from the lower-K zones. The impact of permanganate treatment on mass flux behavior was examined by conducting water floods after permanganate injection. The results were compared to those of water-flood control experiments. The amount of water flushing required for complete contaminant mass removal was reduced for all permanganate treatments for which complete removal was characterized. However, the nature of the mass-flux-reduction/mass-removal relationship observed during water flooding varied as a function of the specific permanganate treatment.
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Affiliation(s)
- Justin C. Marble
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, Arizona 85721-0038, United States
| | - Kenneth C. Carroll
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, Arizona 85721-0038, United States
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
| | - Hilary Janousek
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
| | - Mark L. Brusseau
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, Arizona 85721-0038, United States
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
- Corresponding author ()
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DiFilippo EL, Carroll KC, Brusseau ML. Impact of organic-liquid distribution and flow-field heterogeneity on reductions in mass flux. J Contam Hydrol 2010; 115:14-25. [PMID: 20434229 PMCID: PMC2884052 DOI: 10.1016/j.jconhyd.2010.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 03/10/2010] [Accepted: 03/19/2010] [Indexed: 05/11/2023]
Abstract
A series of flow-cell experiments was conducted to investigate the impact of organic-liquid distribution and flow-field heterogeneity on the relationship between source-zone mass removal and reductions in contaminant mass flux from the source zone. Changes in source-zone architecture were quantified using image analysis, allowing explicit examination of their impact on the mass-flux-reduction/mass-removal behavior. The results showed that there was minimal reduction in mass flux until a large fraction of mass was removed for systems wherein organic liquid was present solely as residual saturation in regions that were hydraulically accessible. Conversely, significant reductions in mass flux occurred with relatively minimal mass removal for systems wherein organic liquid was present at both residual and higher saturations. The latter systems exhibited multi-step mass-flux-reduction/mass-removal behavior, and characterization of the organic-liquid saturation distribution throughout flushing allowed identification of the cause of the nonideal behavior. The age of the source zone (e.g., extent of mass removal prior to characterization) significantly influenced the observed mass-flux-reduction/mass-removal behavior. The results of this study illustrate the impact of both organic-liquid distribution and flow-field heterogeneity on mass-removal and mass-flux processes.
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Affiliation(s)
- Erica L DiFilippo
- Hydrology and Water Resources, University of Arizona, John W. Harshbarger Building, Tucson, AZ 85721, USA
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Carroll KC, Taylor R, Gray E, Brusseau ML. The impact of composition on the physical properties and evaporative mass transfer of a PCE-diesel immiscible liquid. J Hazard Mater 2009; 164:1074-81. [PMID: 18926630 PMCID: PMC2864079 DOI: 10.1016/j.jhazmat.2008.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2008] [Revised: 09/02/2008] [Accepted: 09/03/2008] [Indexed: 05/04/2023]
Abstract
The impact of immiscible-liquid composition on mass transfer between immiscible liquid and vapor phases was evaluated for a complex mixture of chlorinated solvents and petroleum hydrocarbons. A mixture of tetrachloroethene and diesel was discovered at a site in Tucson, Arizona. Partitioning of tetrachloroethene into a layer of diesel has been observed, with resultant concentrations of tetrachloroethene up to approximately 15% by weight. The density, viscosity, surface tension, and interfacial tension were measured for tetrachloroethene-diesel mixtures with tetrachloroethene fractions ranging from 7% to 32%, and the results indicated that immiscible-liquid composition did impact the physical properties of the tetrachloroethene-diesel mixture. The results of batch phase-partitioning experiments were compared to predictions based on Raoult's Law, and the analysis indicated that immiscible-liquid/vapor and immiscible-liquid/water partitioning were both essentially ideal. Flow-cell experiments were conducted to characterize steady-state tetrachloroethene removal from the tetrachloroethene-diesel mixture via vapor extraction. The effluent concentrations for the experiment conducted with free-phase immiscible liquid were comparable to equilibrium values. Conversely, the effluent concentrations were significantly lower for the experiment wherein a residual saturation of immiscible liquid was distributed within sand. The lower concentrations for the latter experiment were attributed to dilution effects associated with a nonuniform distribution of immiscible liquid within the flow cell.
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Affiliation(s)
- Kenneth C. Carroll
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, Arizona 85721-0038, United States
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
| | - Renee Taylor
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
| | - Evan Gray
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
| | - Mark L. Brusseau
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, Arizona 85721-0038, United States
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
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Carroll KC, Brusseau ML. Dissolution, cyclodextrin-enhanced solubilization, and mass removal of an ideal multicomponent organic liquid. J Contam Hydrol 2009; 106:62-72. [PMID: 19233508 PMCID: PMC2867052 DOI: 10.1016/j.jconhyd.2009.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 01/14/2009] [Accepted: 01/14/2009] [Indexed: 05/11/2023]
Abstract
Laboratory experiments and mathematical modeling were conducted to examine the influence of a hydroxypropyl-beta-cyclodextrin (HPCD) solution on the dissolution of single- and three-component organic liquids. The results of batch experiments showed that HPCD-enhanced solubilization of the organic-liquid mixtures was ideal (describable using Raoult's Law), and that solubilization-enhancement factors were independent of mixture composition. Addition of the HPCD solution to columns containing residual saturations of the organic liquid enhanced the dissolution and removal of all three compounds in the mixture. The results of the column experiments and mathematical modeling suggest that solubilization was ideal for both water and cyclodextrin flushing. Concomitantly, the mass-flux reduction versus mass removal behavior was ideal for all experiments. Mass transfer was increased for HPCD solubilization relative to the water flushing due to solubility and concentration-gradient enhancement. Organic-liquid composition did not significantly impact mass transfer coefficients, and fractional mass removal behavior during HPCD solubilization was nearly identical for each compound whether present as a single component or in a mixture. Additionally, mass transfer coefficients for aqueous and HPCD solubilization for single and multicomponent mixtures were not statistically different upon normalizing by the solubility enhancement factor.
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Affiliation(s)
- Kenneth C. Carroll
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, Arizona 85721-0038, United States
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
| | - Mark L. Brusseau
- Department of Soil, Water and Environmental Science, University of Arizona, 429 Shantz Building #38, P.O. Box 210038, Tucson, Arizona 85721-0038, United States
- Department of Hydrology and Water Resources, University of Arizona, Harshbarger Building #11, Tucson, Arizona 85721-0038, United States
- Corresponding author ()
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Carroll KC, Artiola JF, Brusseau ML. Transport of molybdenum in a biosolid-amended alkaline soil. Chemosphere 2006; 65:778-85. [PMID: 16674987 DOI: 10.1016/j.chemosphere.2006.03.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Revised: 03/15/2006] [Accepted: 03/18/2006] [Indexed: 05/09/2023]
Abstract
The transport of molybdenum (Mo) in a biosolid-amended, alkaline, agricultural soil was examined in the research reported herein. Batch-equilibrium and miscible-displacement experiments were conducted to examine the transport of Mo in soil with and without 10% by weight biosolid amendment. The results of geochemical modeling, conducted using PHREEQC, indicated that no mineral dissolution or precipitation reactions were expected for the system under the prevailing conditions. Sorption equilibrium coefficients (Kd) obtained from moment analysis of the Mo breakthrough curves were similar to those calculated from the results of the batch-equilibrium experiments. Mo sorption was greater for the biosolid-amended soil (Kd of 1.3 versus 0.35). Sorption of Mo was shown to be linear, rate limited, and reversible for both unamended and amended soil. The results suggest that Mo associated with biosolid-amended soils is relatively bioavailable and mobile.
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Affiliation(s)
- Kenneth C Carroll
- Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85705, USA
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Ross TL, Merz WG, Farkosh M, Carroll KC. Comparison of an automated repetitive sequence-based PCR microbial typing system to pulsed-field gel electrophoresis for analysis of outbreaks of methicillin-resistant Staphylococcus aureus. J Clin Microbiol 2005; 43:5642-7. [PMID: 16272498 PMCID: PMC1287783 DOI: 10.1128/jcm.43.11.5642-5647.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rapid and sensitive methods for accurate strain delineation are essential for monitoring and preventing transmission of methicillin-resistant Staphylococcus aureus (MRSA). Pulsed-field gel electrophoresis (PFGE) has been the standard technique for strain typing most bacterial species including MRSA. The goal of this study was to compare the performance of the DiversiLab microbial typing system (Bacterial BarCodes, Inc., Houston, TX) (rep-PCR) to that of PFGE for typing MRSA isolates from five well-defined outbreaks. The DiversiLab rep-PCR assay is a rapid, semiautomated method based on PCR amplification of specific regions between noncoding repetitive sequences in the bacterial genome. rep-PCR was performed according to the manufacturer's recommendations, and the results were analyzed and dendrograms were generated using the DiversiLab analysis software (version 2.1.66 a). PFGE was performed and interpreted according to published procedures. rep-PCR results using similarity indices (SI) of 80%, 85%, and 90% were compared to PFGE analysis. In addition, intra- and interrun reproducibility was determined for rep-PCR. Overall, correct assignment to outbreak versus nonoutbreak clusters occurred for 91 of 109 isolates (85% agreement) when using a SI of 85%. For each specific outbreak, concordance between rep-PCR and PFGE ranged from 73% to 100%. There were 18 discrepant results (17%). Fourteen isolates were unique by PFGE, but they were placed in clusters by rep-PCR; the other 4 were placed in clusters different from those assigned by PFGE. Intra- and interrun reproducibility was excellent. Times to results were 12 to 24 h for rep-PCR compared to 2 to 4 days for PFGE. Rapid, standardized results and excellent reproducibility make rep-PCR a valuable tool for use in MRSA investigations. However, since rep-PCR was less discriminatory than PFGE, we recommend that it be used to screen isolates, followed by testing isolates which share the same rep-PCR pattern with a more sensitive method, such as PFGE or multilocus sequence typing.
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Affiliation(s)
- T L Ross
- The Johns Hopkins Hospital, Meyer B1-193, 600 N. Wolfe St., Baltimore, MD 21287-7093, USA.
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Cosgrove SE, Carroll KC, Perl TM. Staphylococcus aureus with reduced susceptibility to vancomycin. Clin Infect Dis 2004; 39:539-45. [PMID: 15356818 DOI: 10.1086/422458] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2004] [Accepted: 04/08/2004] [Indexed: 01/02/2023] Open
Abstract
Infections with Staphylococcus aureus with reduced susceptibility to vancomycin continue to be reported, including 2 cases caused by S. aureus isolates with full resistance to vancomycin. This review first outlines the definitions of vancomycin-intermediate S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) and risk factors for infection. Next, we describe the mechanisms of resistance and methods of laboratory detection of the organisms. Finally, we address infection control and management issues associated with isolation of VISA and VRSA.
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Affiliation(s)
- S E Cosgrove
- Division of Infectious Disease, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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Carroll KC, Adamson K, Korgenski K, Croft A, Hankemeier R, Daly J, Park CH. Comparison of a Commercial Reversed Passive Latex Agglutination Assay to an Enzyme Immunoassay for the Detection of Shiga Toxin-Producing Escherichia coli. Eur J Clin Microbiol Infect Dis 2003; 22:689-92. [PMID: 14574618 DOI: 10.1007/s10096-003-1053-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A multicenter study was performed to compare the performance of a prototypic reversed passive latex agglutination assay (VTEC Screen "Seiken"; Denka-Seiken, Japan) with the Premier EHEC Enzyme Immunoassay (Meridian Diagnostics, USA) for the detection of Shiga toxin in 554 diarrheal stool samples. Standard culture on sorbitol MacConkey agar and the use of latex agglutination reagents were included to identify the Escherichia coli O157, O26 and O111 serotypes. There was 99% agreement between the VTEC screen and enzyme immunoassay (kappa=0.823). Seventeen samples were positive for toxin by one or both assays. One toxin-positive sample using the enzyme immunoassay and four positive samples using the VTEC Screen could not be confirmed. Serotypes identified included: O157:H7 (n=8), O26 (n=2), O111 (n=1) and O45:H2 (n=1). The VTEC screen is easy to perform and comparable to the Meridian EHEC test for detection of Shiga toxin in clinical samples.
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Affiliation(s)
- K C Carroll
- Department of Pathology, ARUP Laboratories, Inc./ University of Utah, 500 Chipeta Way, Salt Lake City, UT 84108, USA.
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Cloud JL, Neal H, Rosenberry R, Turenne CY, Jama M, Hillyard DR, Carroll KC. Identification of Mycobacterium spp. by using a commercial 16S ribosomal DNA sequencing kit and additional sequencing libraries. J Clin Microbiol 2002; 40:400-6. [PMID: 11825949 PMCID: PMC153382 DOI: 10.1128/jcm.40.2.400-406.2002] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Current methods for identification of Mycobacterium spp. rely upon time-consuming phenotypic tests, mycolic acid analysis, and narrow-spectrum nucleic acid probes. Newer approaches include PCR and sequencing technologies. We evaluated the MicroSeq 500 16S ribosomal DNA (rDNA) bacterial sequencing kit (Applied Biosystems, Foster City, Calif.) for its ability to identify Mycobacterium isolates. The kit is based on PCR and sequencing of the first 500 bp of the bacterial rRNA gene. One hundred nineteen mycobacterial isolates (94 clinical isolates and 25 reference strains) were identified using traditional phenotypic methods and the MicroSeq system in conjunction with separate databases. The sequencing system gave 87% (104 of 119) concordant results when compared with traditional phenotypic methods. An independent laboratory using a separate database analyzed the sequences of the 15 discordant samples and confirmed the results. The use of 16S rDNA sequencing technology for identification of Mycobacterium spp. provides more rapid and more accurate characterization than do phenotypic methods. The MicroSeq 500 system simplifies the sequencing process but, in its present form, requires use of additional databases such as the Ribosomal Differentiation of Medical Microorganisms (RIDOM) to precisely identify subtypes of type strains and species not currently in the MicroSeq library.
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Affiliation(s)
- J L Cloud
- Associated Regional and University Pathologists (ARUP), Institute for Clinical and Experimental Pathology, Salt Lake City, Utah 84108, USA.
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