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Zhao Y, Zhang X, Jian Z, Gong Y, Meng X. Effect of landfill leachate on arsenic migration and transformation in shallow groundwater systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:5032-5042. [PMID: 38148459 DOI: 10.1007/s11356-023-31629-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 12/16/2023] [Indexed: 12/28/2023]
Abstract
Arsenic contamination of groundwater has affected human health and environmental safety worldwide. Hundreds of millions of people in more than 100 countries around the world are directly or indirectly troubled by arsenic-contaminated groundwater. In addition, arsenic contamination of groundwater caused by leakage of leachate from municipal solid waste landfills has occurred in some countries and regions, which has attracted widespread attention. Understanding how domestic waste landfill leachate affects the arsenic's migration and transformation in shallow groundwater is crucial for accurate assessment of the distribution and ecological hazards of arsenic in groundwater. Based on literature review, this study systematically summarized and discussed the basic characteristics of landfill leachate, the mechanism of arsenic pollution in groundwater, and the effect of landfill leachate on the migration and transformation of arsenic in groundwater. Combined with relevant research findings and practical experience, countermeasures and suggestions to limit the impact of landfill leachate on the migration and transformation of arsenic in groundwater are put forward.
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Affiliation(s)
- Ying Zhao
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
- State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Xinyi Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
- State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
| | - Zhiqiang Jian
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
- State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Yaping Gong
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
- State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
| | - Xiaoguang Meng
- Center for Environmental Systems, Department of Civil, Environmental & Ocean Engineering, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
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Zhao W, Whelton HL, Blong JC, Shillito LM, Jenkins DL, Bull ID. Volatile organic compounds (VOCs) as a rapid means for assessing the source of coprolites. iScience 2023; 26:106806. [PMID: 37255664 PMCID: PMC10225897 DOI: 10.1016/j.isci.2023.106806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/22/2022] [Accepted: 05/01/2023] [Indexed: 06/01/2023] Open
Abstract
The odor of rehydrated coprolites can be used as an informal means of fecal identification. To date, the analysis of volatiles emitted by coprolites from different sources has not been attempted, and the possibility of utilizing volatile organic compounds (VOCs) as fecal biomarkers unexplored. VOCs released by coprolites from the Paisley Caves, were analyzed using solid-phase microextraction (SPME), to assess the variance of results from different coprolites (carnivores, herbivores, or humans). Coprolites from carnivores can be clearly distinguished from those produced by herbivores and humans; these latter two are separated to a lesser degree. Eight discriminatory compounds differentiated between the coprolite sources, and their identities were verified using reference standards. Coprolites and their associated sediments could not be differentiated between using this method, suggesting leaching of VOCs into the burial matrix. This work provides an alternative, more rapid way to assess coprolite origin.
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Affiliation(s)
- Wanyue Zhao
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
| | - Helen L. Whelton
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
| | - John C. Blong
- Department of Anthropology, Washington State University, College Hall, Pullman, WA 99164-4910, USA
| | - Lisa-Marie Shillito
- School of History, Classics and Archaeology, Armstrong Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Dennis L. Jenkins
- Museum of Natural and Cultural History, University of Oregon, Eugene, OR 97403, USA
| | - Ian D. Bull
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, UK
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Pisharody L, Gopinath A, Malhotra M, Nidheesh PV, Kumar MS. Occurrence of organic micropollutants in municipal landfill leachate and its effective treatment by advanced oxidation processes. CHEMOSPHERE 2022; 287:132216. [PMID: 34517234 DOI: 10.1016/j.chemosphere.2021.132216] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 08/25/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
Landfilling is the most prominently adopted disposal technique for managing municipal solid waste across the globe. However, the main drawback associated with this method is the generation of leachate from the landfill site. Leachate, a highly concentrated liquid consisting of both organic and inorganic components arises environmental issues as it contaminates the nearby aquifers. Landfill leachate treatment by conventional methods is not preferred as the treatment methods are not much effective to remove these pollutants. Advanced oxidation processes (AOPs) based on both hydroxyl and sulfate radicals could be a promising method to remove the micropollutants completely or convert them to non-toxic compounds. The current review focuses on the occurrence of micropollutants in landfill leachate, their detection methods and removal from landfill leachate using AOPs. Pharmaceuticals and personal care products occur in the range of 10-1 to more than 100 μg L-1 whereas phthalates were found below the detectable limit to 384 μg L-1, pesticides in the order of 10-1 μg L-1 and polyaromatic hydrocarbons occur in concentration from 10-2 to 114.7 μg L-1. Solid-phase extraction is the most preferred method for extracting micropollutants from leachate and liquid chromatography (LC) - mass spectrophotometer (MS) for detecting the micropollutants. Limited studies have been focused on AOPs as a potential method for the degradation of micropollutants in landfill leachate. The potential of Fenton based techniques, electrochemical AOPs and ozonation are investigated for the removal of micropollutants from leachate whereas the applicability of photocatalysis for the removal of a wide variety of micropollutants from leachate needs in-depth studies.
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Affiliation(s)
- Lakshmi Pisharody
- The Zuckerberg Institute of Water Research, Ben-Gurion University, Israel
| | - Ashitha Gopinath
- Environmental Impact and Sustainability Division, CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra, India
| | - Milan Malhotra
- Environmental Science and Engineering Department, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - P V Nidheesh
- Environmental Impact and Sustainability Division, CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra, India.
| | - M Suresh Kumar
- Environmental Impact and Sustainability Division, CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra, India
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Ziegler BA, Schreiber ME, Cozzarelli IM, Crystal Ng GH. A mass balance approach to investigate arsenic cycling in a petroleum plume. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 231:1351-1361. [PMID: 28943347 DOI: 10.1016/j.envpol.2017.08.110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/31/2017] [Accepted: 08/30/2017] [Indexed: 05/12/2023]
Abstract
Natural attenuation of organic contaminants in groundwater can give rise to a series of complex biogeochemical reactions that release secondary contaminants to groundwater. In a crude oil contaminated aquifer, biodegradation of petroleum hydrocarbons is coupled with the reduction of ferric iron (Fe(III)) hydroxides in aquifer sediments. As a result, naturally occurring arsenic (As) adsorbed to Fe(III) hydroxides in the aquifer sediment is mobilized from sediment into groundwater. However, Fe(III) in sediment of other zones of the aquifer has the capacity to attenuate dissolved As via resorption. In order to better evaluate how long-term biodegradation coupled with Fe-reduction and As mobilization can redistribute As mass in contaminated aquifer, we quantified mass partitioning of Fe and As in the aquifer based on field observation data. Results show that Fe and As are spatially correlated in both groundwater and aquifer sediments. Mass partitioning calculations demonstrate that 99.9% of Fe and 99.5% of As are associated with aquifer sediment. The sediments act as both sources and sinks for As, depending on the redox conditions in the aquifer. Calculations reveal that at least 78% of the original As in sediment near the oil has been mobilized into groundwater over the 35-year lifespan of the plume. However, the calculations also show that only a small percentage of As (∼0.5%) remains in groundwater, due to resorption onto sediment. At the leading edge of the plume, where groundwater is suboxic, sediments sequester Fe and As, causing As to accumulate to concentrations 5.6 times greater than background concentrations. Current As sinks can serve as future sources of As as the plume evolves over time. The mass balance approach used in this study can be applied to As cycling in other aquifers where groundwater As results from biodegradation of an organic carbon point source coupled with Fe reduction.
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Affiliation(s)
- Brady A Ziegler
- Virginia Tech, Department of Geosciences, 926 W. Campus Dr., Blacksburg, VA 24061, USA.
| | - Madeline E Schreiber
- Virginia Tech, Department of Geosciences, 926 W. Campus Dr., Blacksburg, VA 24061, USA.
| | | | - G-H Crystal Ng
- University of Minnesota, Department of Earth Sciences, 310 Pillsbury Dr. SE, Minneapolis, MN 55455, USA.
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Xie H, Yan H, Feng S, Wang Q, Chen P. An analytical model for contaminant transport in landfill composite liners considering coupled effect of consolidation, diffusion, and degradation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:19362-19375. [PMID: 27370538 DOI: 10.1007/s11356-016-7147-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 06/23/2016] [Indexed: 06/06/2023]
Abstract
One-dimensional mathematical model is developed to investigate the behavior of contaminant transport in landfill composite liner system considering coupled effect of consolidation, diffusion, and degradation. The first- and second-type bottom boundary conditions are used to derive the steady-state and quasi-steady-state analytical solutions. The concentration profiles obtained by the proposed analytical solution are in good agreement with those obtained by the laboratory tests. The bottom concentration and flux of the soil liners can be greatly reduced when the degradation effect and porosity changing are considered. For the case under steady-state, the bottom flux and concentration for the case with t 1/2 =10 years can be 2.8 and 5.5 times lower than those of the case with t 1/2 =100 years, respectively. The bottom concentration and flux of the soil liners can be greatly reduced when the coefficient of volume compressibility decreases. For quasi-steady-state and with t 1/2 = 10 years, the bottom flux and concentration for the case with m v = 0.02/MPa can be 17.4 and 21 times lower than the case with m v = 0.5/MPa. This may be due to the fact that the true fluid velocity induced by consolidation is greater for the case with high coefficient of volume compressibility. The bottom flux for the case with single compacted clay liner (CCL) can be 1.5 times larger than that for the case with GMB/CCL considering diffusion and consolidation for DCM. The proposed analytical model can be used for verification of more complicated numerical models and assessment of the coupled effect of diffusion, consolidation, and degradation on contaminant transport in landfill liner systems.
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Affiliation(s)
- Haijian Xie
- College of Civil Engineering and Architecture, Zhejiang University, 866, Yuhangtang Road, Hangzhou, 310058, China.
| | - Huaxiang Yan
- College of Civil Engineering and Architecture, Zhejiang University, 866, Yuhangtang Road, Hangzhou, 310058, China
| | - Shijin Feng
- Department of Geotechnical Engineering, Tongji University, Shanghai, 200092, China
| | - Qiao Wang
- College of Civil Engineering and Architecture, Zhejiang University, 866, Yuhangtang Road, Hangzhou, 310058, China
| | - Peixiong Chen
- Second Institute of Oceanography, SOA, Hangzhou, 310012, China
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Bekins BA, Cozzarelli IM, Erickson ML, Steenson RA, Thorn KA. Crude Oil Metabolites in Groundwater at Two Spill Sites. GROUND WATER 2016; 54:681-691. [PMID: 27010754 DOI: 10.1111/gwat.12419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/22/2016] [Indexed: 06/05/2023]
Abstract
Two groundwater plumes in north central Minnesota with residual crude oil sources have 20 to 50 mg/L of nonvolatile dissolved organic carbon (NVDOC). These values are over 10 times higher than benzene and two to three times higher than Diesel Range Organics in the same wells. On the basis of previous work, most of the NVDOC consists of partial transformation products from the crude oil. Monitoring data from 1988 to 2015 at one of the sites located near Bemidji, MN show that the plume of metabolites is expanding toward a lakeshore located 335 m from the source zone. Other mass balance studies of the site have demonstrated that the plume expansion is driven by the combined effect of continued presence of the residual crude oil source and depletion of the electron accepting capacity of solid phase iron oxide and hydroxides on the aquifer sediments. These plumes of metabolites are not covered by regulatory monitoring and reporting requirements in Minnesota and other states. Yet, a review of toxicology studies indicates that polar metabolites of crude oil may pose a risk to aquatic and mammalian species. Together the results suggest that at sites where residual sources are present, monitoring of NVDOC may be warranted to evaluate the fates of plumes of hydrocarbon transformation products.
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Affiliation(s)
| | | | | | - Ross A Steenson
- San Francisco Bay Regional Water Quality Control Board, 1515 Clay St., Oakland, CA, 94612
| | - Kevin A Thorn
- U.S. Geological Survey, Denver Federal Center, MS-408, Building 95, Lakewood, CO, 80225
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Oturan N, van Hullebusch ED, Zhang H, Mazeas L, Budzinski H, Le Menach K, Oturan MA. Occurrence and Removal of Organic Micropollutants in Landfill Leachates Treated by Electrochemical Advanced Oxidation Processes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:12187-12196. [PMID: 26378656 DOI: 10.1021/acs.est.5b02809] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In recent years, electrochemical advanced oxidation processes have been shown to be an effective alternative for the removal of refractory organic compounds from water. This study is focused on the effective removal of recalcitrant organic matter (micropollutants, humic substances, etc.) present in municipal solid waste landfill leachates. A mixture of eight landfill leachates has been studied by the electro-Fenton process using a Pt or boron-doped diamond (BDD) anode and a carbon felt cathode or by the anodic oxidation process with a BDD anode. These processes exhibit great oxidation ability due to the in situ production of hydroxyl radicals ((•)OH), a highly powerful oxidizing species. Both electrochemical processes were shown to be efficient in the removal of dissolved total organic carbon (TOC) from landfill leachates. Regarding the electro-Fenton process, the replacement of the classical anode Pt by the anode BDD allows better performance in terms of dissolved TOC removal. The occurrence and removal yield of 19 polycyclic aromatic hydrocarbons, 15 volatile organic compounds, 7 alkylphenols, 7 polychlorobiphenyls, 5 organochlorine pesticides, and 2 polybrominated diphenyl ethers in landfill leachate were also investigated. Both electrochemical processes allow one to reach a quasicomplete removal (about 98%) of these organic micropollutants.
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Affiliation(s)
- Nihal Oturan
- Laboratoire Géomatériaux et Environnement, Université Paris-Est, EA 4508, UPEM , 5 Boulevard Descartes, Marne-la-Vallée 77454 Cedex 2, France
| | - Eric D van Hullebusch
- Laboratoire Géomatériaux et Environnement, Université Paris-Est, EA 4508, UPEM , 5 Boulevard Descartes, Marne-la-Vallée 77454 Cedex 2, France
| | - Hui Zhang
- Department of Environmental Engineering, Wuhan University , P.O. Box C319 Luoyu Road 129#, Wuhan 430079, China
| | - Laurent Mazeas
- Hydrosystems and Bioprocesses Research Unit, IRSTEA , 1 Rue Pierre-Gilles de Gennes, CS 10030, Antony F-92761 Cedex, France
| | - Hélène Budzinski
- Environnements et Paléoenvironnements Océaniques et Continentaux, EPOC-UMR 5805 CNRS, Laboratoire de Physico-et Toxico-Chimie de l'environnement (LPTC), Université de Bordeaux, Bâtiment A12, 351 Cours de la Libération, 33405 Talence, France
| | - Karyn Le Menach
- Environnements et Paléoenvironnements Océaniques et Continentaux, EPOC-UMR 5805 CNRS, Laboratoire de Physico-et Toxico-Chimie de l'environnement (LPTC), Université de Bordeaux, Bâtiment A12, 351 Cours de la Libération, 33405 Talence, France
| | - Mehmet A Oturan
- Laboratoire Géomatériaux et Environnement, Université Paris-Est, EA 4508, UPEM , 5 Boulevard Descartes, Marne-la-Vallée 77454 Cedex 2, France
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Arora B, Mohanty BP, McGuire JT. An integrated Markov chain Monte Carlo algorithm for upscaling hydrological and geochemical parameters from column to field scale. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 512-513:428-443. [PMID: 25644839 DOI: 10.1016/j.scitotenv.2015.01.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 01/13/2015] [Accepted: 01/18/2015] [Indexed: 06/04/2023]
Abstract
Predicting and controlling the concentrations of redox-sensitive elements are primary concerns for environmental remediation of contaminated sites. These predictions are complicated by dynamic flow processes as hydrologic variability is a governing control on conservative and reactive chemical concentrations. Subsurface heterogeneity in the form of layers and lenses further complicates the flow dynamics of the system impacting chemical concentrations including redox-sensitive elements. In response to these complexities, this study investigates the role of heterogeneity and hydrologic processes in an effective parameter upscaling scheme from the column to the landfill scale. We used a Markov chain Monte Carlo (MCMC) algorithm to derive upscaling coefficients for hydrological and geochemical parameters, which were tested for variations across heterogeneous systems (layers and lenses) and interaction of flow processes based on the output uncertainty of dominant biogeochemical concentrations at the Norman Landfill site, a closed municipal landfill with prevalent organic and trace metal contamination. The results from MCMC analysis indicated that geochemical upscaling coefficients based on effective concentration ratios incorporating local heterogeneity across layered and lensed systems produced better estimates of redox-sensitive biogeochemistry at the field scale. MCMC analysis also suggested that inclusion of hydrological parameters in the upscaling scheme reduced the output uncertainty of effective mean geochemical concentrations by orders of magnitude at the Norman Landfill site. This was further confirmed by posterior density plots of the scaling coefficients that revealed unimodal characteristics when only geochemical processes were involved, but produced multimodal distributions when hydrological parameters were included. The multimodality again suggests the effect of heterogeneity and lithologic variability on the distribution of redox-sensitive elements at the Norman Landfill site.
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Affiliation(s)
- Bhavna Arora
- Water Management & Hydrologic Science Program, Texas A&M University, USA; Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Binayak P Mohanty
- Water Management & Hydrologic Science Program, Texas A&M University, USA
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Sizirici B, Tansel B. Parametric fate and transport profiling for selective groundwater monitoring at closed landfills: a case study. WASTE MANAGEMENT (NEW YORK, N.Y.) 2015; 38:263-70. [PMID: 25596670 DOI: 10.1016/j.wasman.2014.12.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 12/11/2014] [Accepted: 12/23/2014] [Indexed: 05/22/2023]
Abstract
Monitoring contaminant concentrations in groundwater near closed municipal solid waste landfills requires long term monitoring program which can require significant investment for monitoring efforts. The groundwater monitoring data from a closed landfill in Florida was analyzed to reduce the monitoring efforts. The available groundwater monitoring data (collected over 20 years) were analyzed (i.e., type, concentration and detection level) to identify the trends in concentrations of contaminants and spatial mobility characteristics of groundwater (i.e., groundwater direction, retardation characteristics of contaminants, groundwater well depth, subsoil characteristics), to identify critical monitoring locations. Among the 7 groundwater monitoring well clusters (totaling 22 wells) in landfill, the data from two monitoring well clusters (totaling 7 wells) located along direction of groundwater flow showed similarities (the highest concentrations and same contaminants). These wells were used to assess the transport characteristics of the contaminants. Some parameters (e.g., iron, sodium, ammonia as N, chlorobenzene, 1,4-dichlorobenzene) showed decreasing trends in the groundwater due to soil absorption and retardation. Metals were retarded by ion exchange and their concentration increased by depth indicating soil reached breakthrough over time. Soil depth did not have a significant effect on the concentrations of volatile organic contaminants. Based on the analyses, selective groundwater monitoring modifications were developed for effective monitoring to acquire data from the most critical locations which may be impacted by leachate mobility. The adjustments in the sampling strategy reduced the amount of data collected by as much as 97.7% (i.e., total number of parameters monitored). Effective groundwater sampling strategies can save time, effort and monitoring costs while improving the quality of sample handling and data analyses for better utilization of post closure monitoring funds.
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Affiliation(s)
- Banu Sizirici
- Civil, Infrastructure and Environmental Engineering Department, Khalifa University, Abu Dhabi, United Arab Emirates
| | - Berrin Tansel
- Civil and Environmental Engineering Department, Florida International University, Miami, FL, USA
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Masoner JR, Kolpin DW, Furlong ET, Cozzarelli IM, Gray JL, Schwab EA. Contaminants of emerging concern in fresh leachate from landfills in the conterminous United States. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:2335-54. [PMID: 25111596 DOI: 10.1039/c4em00124a] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
To better understand the composition of contaminants of emerging concern (CECs) in landfill leachate, fresh leachate from 19 landfills was sampled across the United States during 2011. The sampled network included 12 municipal and 7 private landfills with varying landfill waste compositions, geographic and climatic settings, ages of waste, waste loads, and leachate production. A total of 129 out of 202 CECs were detected during this study, including 62 prescription pharmaceuticals, 23 industrial chemicals, 18 nonprescription pharmaceuticals, 16 household chemicals, 6 steroid hormones, and 4 plant/animal sterols. CECs were detected in every leachate sample, with the total number of detected CECs in samples ranging from 6 to 82 (median = 31). Bisphenol A (BPA), cotinine, and N,N-diethyltoluamide (DEET) were the most frequently detected CECs, being found in 95% of the leachate samples, followed by lidocaine (89%) and camphor (84%). Other frequently detected CECs included benzophenone, naphthalene, and amphetamine, each detected in 79% of the leachate samples. CEC concentrations spanned six orders of magnitude, ranging from ng L(-1) to mg L(-1). Industrial and household chemicals were measured in the greatest concentrations, composing more than 82% of the total measured CEC concentrations. Maximum concentrations for three household and industrial chemicals, para-cresol (7 020 000 ng L(-1)), BPA (6 380 000 ng L(-1)), and phenol (1 550 000 ng L(-1)), were the largest measured, with these CECs composing 70% of the total measured CEC concentrations. Nonprescription pharmaceuticals represented 12%, plant/animal sterols 4%, prescription pharmaceuticals 1%, and steroid hormones <1% of the total measured CEC concentrations. Leachate from landfills in areas receiving greater amounts of precipitation had greater frequencies of CEC detections and concentrations in leachate than landfills receiving less precipitation.
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Affiliation(s)
- Jason R Masoner
- U.S. Geological Survey, 202 NW 66th Bldg. 7, Oklahoma City, OK 73116, USA.
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Milosevic N, Qiu S, Elsner M, Einsiedl F, Maier MP, Bensch HKV, Albrechtsen HJ, Bjerg PL. Combined isotope and enantiomer analysis to assess the fate of phenoxy acids in a heterogeneous geologic setting at an old landfill. WATER RESEARCH 2013; 47:637-649. [PMID: 23168311 DOI: 10.1016/j.watres.2012.10.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/20/2012] [Accepted: 10/14/2012] [Indexed: 06/01/2023]
Abstract
Phenoxy acid herbicides and their potential metabolites represent industrial or agricultural waste that impacts groundwater and surface waters through leaching from old landfills throughout the world. Fate assessment of dichlorprop and its putative metabolite 4-CPP (2-(4-chlorophenoxy)propionic acid) is frequently obstructed by inconclusive evidence from redox conditions, heterogeneous geologic settings (e.g. clay till) and ambiguous parent-daughter relationships (i.e. 4-CPP may be daughter product or impurity of dichlorprop). For the first time, a combination of four methods was tested to assess transformation of phenoxy acids at a contaminated landfill (Risby site): analysis of (i) parent and daughter compound concentrations, (ii) enantiomer ratios (iii) compound-specific isotope analysis and (iv) enantiomer-specific isotope analysis. Additionally, water isotopes and chloride were used as conservative tracers to delineate two distinct groundwater flow paths in the clay till. Metabolite concentrations and isotope ratios of chlorinated ethenes demonstrated dechlorination activity in the area with highest leachate concentrations (hotspot) indicating favorable conditions also for dechlorination of dichlorprop to 4-CPP and further to phenoxypropionic acid. Combined evidence from concentrations, enantiomer ratios and isotope ratios of dichlorprop and 4-CPP confirmed their dechlorination in the hotspot and gave evidence for further degradation of 4-CPP downgradient of the hotspot. A combination of 4-CPP enantiomer and isotope analysis indicated different enantioselectivity and isotope fractionation, i.e. different modes of 4-CPP degradation, at different locations. This combined information was beyond the reach of any of the methods applied alone demonstrating the power of the new combined approach.
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Affiliation(s)
- N Milosevic
- Department of Environmental Engineering, Technical University of Denmark, Miljoevej, Building 113, DK-2800 Kgs. Lyngby, Denmark.
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Amos RT, Bekins BA, Cozzarelli IM, Voytek MA, Kirshtein JD, Jones EJP, Blowes DW. Evidence for iron-mediated anaerobic methane oxidation in a crude oil-contaminated aquifer. GEOBIOLOGY 2012; 10:506-517. [PMID: 22925422 DOI: 10.1111/j.1472-4669.2012.00341.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 07/12/2012] [Indexed: 05/28/2023]
Abstract
In a methanogenic crude oil contaminated aquifer near Bemidji, Minnesota, the decrease in dissolved CH(4) concentrations along the groundwater flow path, along with the positive shift in δ(13) C(CH) (4) and negative shift in δ(13) C(DIC) , is indicative of microbially mediated CH(4) oxidation. Calculations of electron acceptor transport across the water table, through diffusion, recharge, and the entrapment and release of gas bubbles, suggest that these processes can account for at most 15% of the observed total reduced carbon oxidation, including CH(4) . In the anaerobic plume, the characteristic Fe(III)-reducing genus Geobacter was the most abundant of the microbial groups tested, and depletion of labile sediment iron is observed over time, confirming that reduced carbon oxidation coupled to iron reduction is an important process. Electron mass balance calculations suggest that organic carbon sources in the aquifer, BTEX and non-volatile dissolved organic carbon, are insufficient to account for the loss in sediment Fe(III), implying that CH(4) oxidation may also be related to Fe(III) reduction. The results support a hypothesis of Fe(III)-mediated CH(4) oxidation in the contaminated aquifer.
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Affiliation(s)
- R T Amos
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, ON, Canada.
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Lu Z, He Z, Parisi VA, Kang S, Deng Y, Van Nostrand JD, Masoner JR, Cozzarelli IM, Suflita JM, Zhou J. GeoChip-based analysis of microbial functional gene diversity in a landfill leachate-contaminated aquifer. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:5824-5833. [PMID: 22533634 DOI: 10.1021/es300478j] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The functional gene diversity and structure of microbial communities in a shallow landfill leachate-contaminated aquifer were assessed using a comprehensive functional gene array (GeoChip 3.0). Water samples were obtained from eight wells at the same aquifer depth immediately below a municipal landfill or along the predominant downgradient groundwater flowpath. Functional gene richness and diversity immediately below the landfill and the closest well were considerably lower than those in downgradient wells. Mantel tests and canonical correspondence analysis (CCA) suggested that various geochemical parameters had a significant impact on the subsurface microbial community structure. That is, leachate from the unlined landfill impacted the diversity, composition, structure, and functional potential of groundwater microbial communities as a function of groundwater pH, and concentrations of sulfate, ammonia, and dissolved organic carbon (DOC). Historical geochemical records indicate that all sampled wells chronically received leachate, and the increase in microbial diversity as a function of distance from the landfill is consistent with mitigation of the impact of leachate on the groundwater system by natural attenuation mechanisms.
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Affiliation(s)
- Zhenmei Lu
- College of Life Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
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15
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Cozzarelli IM, Böhlke JK, Masoner J, Breit GN, Lorah MM, Tuttle MLW, Jaeschke JB. Biogeochemical evolution of a landfill leachate plume, Norman, Oklahoma. GROUND WATER 2011; 49:663-87. [PMID: 21314684 DOI: 10.1111/j.1745-6584.2010.00792.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Leachate from municipal landfills can create groundwater contaminant plumes that may last for decades to centuries. The fate of reactive contaminants in leachate-affected aquifers depends on the sustainability of biogeochemical processes affecting contaminant transport. Temporal variations in the configuration of redox zones downgradient from the Norman Landfill were studied for more than a decade. The leachate plume contained elevated concentrations of nonvolatile dissolved organic carbon (NVDOC) (up to 300 mg/L), methane (16 mg/L), ammonium (650 mg/L as N), iron (23 mg/L), chloride (1030 mg/L), and bicarbonate (4270 mg/L). Chemical and isotopic investigations along a 2D plume transect revealed consumption of solid and aqueous electron acceptors in the aquifer, depleting the natural attenuation capacity. Despite the relative recalcitrance of NVDOC to biodegradation, the center of the plume was depleted in sulfate, which reduces the long-term oxidation capacity of the leachate-affected aquifer. Ammonium and methane were attenuated in the aquifer relative to chloride by different processes: ammonium transport was retarded mainly by physical interaction with aquifer solids, whereas the methane plume was truncated largely by oxidation. Studies near plume boundaries revealed temporal variability in constituent concentrations related in part to hydrologic changes at various time scales. The upper boundary of the plume was a particularly active location where redox reactions responded to recharge events and seasonal water-table fluctuations. Accurately describing the biogeochemical processes that affect the transport of contaminants in this landfill-leachate-affected aquifer required understanding the aquifer's geologic and hydrodynamic framework.
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16
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Zhou C, Wang R, Zhang Y. Fertilizer efficiency and environmental risk of irrigating Impatiens with composting leachate in decentralized solid waste management. WASTE MANAGEMENT (NEW YORK, N.Y.) 2010; 30:1000-1005. [PMID: 20194007 DOI: 10.1016/j.wasman.2010.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Revised: 01/27/2010] [Accepted: 02/01/2010] [Indexed: 05/28/2023]
Abstract
The reduction and reuse of composting leachate is an issue of importance in the field of decentralized solid waste management. In this study, composting leachate from source-separated food waste was treated and subsequently used as liquid fertilizer to irrigate Impatiens (Impatiens balsamina). The leachate was altered by adjusting storage time and dilution, and through addition of microbial inocula. For each test case, the effects of irrigation were monitored by analyzing the Impatiens extension degree, numbers of leaves and flowers, dry weight, and photosynthetic pigment content to assess fertilizer efficiency. The main results obtained revealed that the addition of microbial inocula and lengthening of storage times may lower COD concentrations, adjust pH value and maintain a comparatively high level of nutrient contents. By adding microbial inocula, a COD concentration of 9.6% and BOD(5) concentration of 6.7% were obtained for non-treated leachate with the same storage time. COD concentrations in leachate decreased to 69.4% after 36weeks storage. Moreover, composting leachate promoted growth of Impatiens. The dry weight biomass of Impatiens irrigated using treated diluted leachate was 1.15-2.94 times that obtained for Impatiens irrigated using tap water. Lastly, following the irrigation of Impatiens over a short period, soil did not accumulate VOCs and heavy metals to levels exceeding relative standards. Further research on heavy metal and salinity accumulation in plants should be undertaken to meet the needs of large-scale applications.
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Affiliation(s)
- Chuanbin Zhou
- State Key Laboratory of Urban and Region Ecology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing 100085, China
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17
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Sartori F, Wade TL, Sericano JL, Mohanty BP, Smith KA. Polycyclic aromatic hydrocarbons in soil of the Canadian river floodplain in Oklahoma. JOURNAL OF ENVIRONMENTAL QUALITY 2010; 39:568-579. [PMID: 20176830 DOI: 10.2134/jeq2009.0270] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The accumulation of polycyclic aromatic hydrocarbons (PAH) in soil, plants, and water may impart negative effects on ecosystem and human health. We quantified the concentration and distribution of 41 PAH (n = 32), organic C, total N, and S (n = 140) and investigated PAH sources using a chronosequence of floodplain soils under a natural vegetation succession. Soil samples were collected between 0- and 260-cm depth in bare land (the control), wetland, forest, and grassland areas near a closed municipal landfill and an active asphalt plant (the contaminant sources) in the north bank of the Canadian River near Norman, OK. Principal component, cluster, and correlation analyses were used to investigate the spatial distribution of PAH, in combination with diagnostic ratios to distinguish pyrogenic vs. petrogenic PAH suites. Total PAH concentration (SigmaPAH) had a mean of 1300 ng g(-1), minimum of 16 ng g(-1), and maximum of 12,000 ng g(-1). At 0- to 20-cm depth, SigmaPAH was 3500 +/- 1600 ng g(-1) (mean +/- 1 SE) near the contaminant sources. The most common compounds were nonalkylated, high molecular weight PAH of pyrogenic origin, i.e., fluoranthene (17%), pyrene (14%), phenanthrene (9%), benzo(b)fluoranthene (7%), chrysene (6%), and benzo(a)anthracene (5%). SigmaPAH in the control (130 +/- 23 ng g(-1)) was comparable to reported concentrations for the rural Great Plains. Perylene had a unique distribution pattern suggesting biological inputs. The main PAH contamination mechanisms were likely atmospheric deposition due to asphalt production at the 0- to 20-cm depth and past landfill operations at deeper depths.
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Affiliation(s)
- Fabio Sartori
- Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843, USA.
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18
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Bombach P, Richnow HH, Kästner M, Fischer A. Current approaches for the assessment of in situ biodegradation. Appl Microbiol Biotechnol 2010; 86:839-52. [PMID: 20174793 DOI: 10.1007/s00253-010-2461-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 01/19/2010] [Accepted: 01/19/2010] [Indexed: 10/19/2022]
Abstract
Considering the high costs and technical difficulties associated with conventional remediation strategies, in situ biodegradation has become a promising approach for cleaning up contaminated aquifers. To verify if in situ biodegradation of organic contaminants is taking place at a contaminated site and to determine if these processes are efficient enough to replace conventional cleanup technologies, a comprehensive characterization of site-specific biodegradation processes is essential. In recent years, several strategies including geochemical analyses, microbial and molecular methods, tracer tests, metabolite analysis, compound-specific isotope analysis, and in situ microcosms have been developed to investigate the relevance of biodegradation processes for cleaning up contaminated aquifers. In this review, we outline current approaches for the assessment of in situ biodegradation and discuss their potential and limitations. We also discuss the benefits of research strategies combining complementary methods to gain a more comprehensive understanding of the complex hydrogeological and microbial interactions governing contaminant biodegradation in the field.
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Affiliation(s)
- Petra Bombach
- Department of Isotope Biogeochemistry, UFZ-Helmholtz Centre for Environmental Research, Leipzig, Germany.
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19
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Cozzarelli IM, Bekins BA, Eganhouse RP, Warren E, Essaid HI. In situ measurements of volatile aromatic hydrocarbon biodegradation rates in groundwater. JOURNAL OF CONTAMINANT HYDROLOGY 2010; 111:48-64. [PMID: 20060615 DOI: 10.1016/j.jconhyd.2009.12.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 12/04/2009] [Accepted: 12/07/2009] [Indexed: 05/28/2023]
Abstract
Benzene and alkylbenzene biodegradation rates and patterns were measured using an in situ microcosm in a crude-oil contaminated aquifer near Bemidji, Minnesota. Benzene-D6, toluene, ethylbenzene, o-, m- and p-xylenes and four pairs of C(3)- and C(4)-benzenes were added to an in situ microcosm and studied over a 3-year period. The microcosm allowed for a mass-balance approach and quantification of hydrocarbon biodegradation rates within a well-defined iron-reducing zone of the anoxic plume. Among the BTEX compounds, the apparent order of persistence is ethylbenzene > benzene > m,p-xylenes > o-xylene >or= toluene. Threshold concentrations were observed for several compounds in the in situ microcosm, below which degradation was not observed, even after hundreds of days. In addition, long lag times were observed before the onset of degradation of benzene or ethylbenzene. The isomer-specific degradation patterns were compared to observations from a multi-year study conducted using data collected from monitoring wells along a flowpath in the contaminant plume. The data were fit with both first-order and Michaelis-Menten models. First-order kinetics provided a good fit for hydrocarbons with starting concentrations below 1mg/L and Michaelis-Menten kinetics were a better fit when starting concentrations were above 1mg/L, as was the case for benzene. The biodegradation rate data from this study were also compared to rates from other investigations reported in the literature.
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Affiliation(s)
- Isabelle M Cozzarelli
- U.S. Geological Survey, 431 National Center, 12201 Sunrise Valley Drive, Reston, VA 20192, USA.
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20
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Buszka PM, Yeskis DJ, Kolpin DW, Furlong ET, Zaugg SD, Meyer MT. Waste-indicator and pharmaceutical compounds in landfill-leachate-affected ground water near Elkhart, Indiana, 2000-2002. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2009; 82:653-9. [PMID: 19290448 DOI: 10.1007/s00128-009-9702-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 02/26/2009] [Indexed: 05/25/2023]
Abstract
Four wells downgradient from a landfill near Elkhart, Indiana were sampled during 2000-2002 to evaluate the presence of waste-indicator and pharmaceutical compounds in landfill-leachate-affected ground water. Compounds detected in leachate-affected ground water included detergent metabolites (p-nonylphenol, nonylphenol monoethoxylate, nonylphenol diethoxylate, and octylphenol monoethoxylate), plasticizers (ethanol-2-butoxy-phosphate and diethylphthalate), a plastic monomer (bisphenol A), disinfectants (1,4-dichlorobenzene and triclosan), an antioxidant (5-methyl-1H-benzotriazole), three fire-retardant compounds (tributylphosphate and tri(2-chloroethyl)phosphate, and tri(dichlorisopropyl)phosphate), and several pharmaceuticals and metabolites (acetaminophen, caffeine, cotinine, 1,7-dimethylxanthine, fluoxetine, and ibuprofen). Acetaminophen, caffeine, and cotinine detections confirm prior indications of pharmaceutical and nicotinate disposal in the landfill.
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Affiliation(s)
- P M Buszka
- US Geological Survey, 5957 Lakeside Blvd, Indianapolis, IN 46278, USA.
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21
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Lorah MM, Cozzarelli IM, Böhlke JK. Biogeochemistry at a wetland sediment-alluvial aquifer interface in a landfill leachate plume. JOURNAL OF CONTAMINANT HYDROLOGY 2009; 105:99-117. [PMID: 19136178 DOI: 10.1016/j.jconhyd.2008.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 10/29/2008] [Accepted: 11/03/2008] [Indexed: 05/27/2023]
Abstract
The biogeochemistry at the interface between sediments in a seasonally ponded wetland (slough) and an alluvial aquifer contaminated with landfill leachate was investigated to evaluate factors that can effect natural attenuation of landfill leachate contaminants in areas of groundwater/surface-water interaction. The biogeochemistry at the wetland-alluvial aquifer interface differed greatly between dry and wet conditions. During dry conditions (low water table), vertically upward discharge was focused at the center of the slough from the fringe of a landfill-derived ammonium plume in the underlying aquifer, resulting in transport of relatively low concentrations of ammonium to the slough sediments with dilution and dispersion as the primary attenuation mechanism. In contrast, during wet conditions (high water table), leachate-contaminated groundwater discharged upward near the upgradient slough bank, where ammonium concentrations in the aquifer where high. Relatively high concentrations of ammonium and other leachate constituents also were transported laterally through the slough porewater to the downgradient bank in wet conditions. Concentrations of the leachate-associated constituents chloride, ammonium, non-volatile dissolved organic carbon, alkalinity, and ferrous iron more than doubled in the slough porewater on the upgradient bank during wet conditions. Chloride, non-volatile dissolved organic carbon (DOC), and bicarbonate acted conservatively during lateral transport in the aquifer and slough porewater, whereas ammonium and potassium were strongly attenuated. Nitrogen isotope variations in ammonium and the distribution of ammonium compared to other cations indicated that sorption was the primary attenuation mechanism for ammonium during lateral transport in the aquifer and the slough porewater. Ammonium attenuation was less efficient, however, in the slough porewater than in the aquifer and possibly occurred by a different sorption mechanism. A stoichiometrically balanced increase in magnesium concentration with decreasing ammonium and potassium concentrations indicated that cation exchange was the sorption mechanism in the slough porewater. Only a partial mass balance could be determined for cations exchanged for ammonium and potassium in the aquifer, indicating that some irreversible sorption may be occurring. Although wetlands commonly are expected to decrease fluxes of contaminants in riparian environments, enhanced attenuation of the leachate contaminants in the slough sediment porewater compared to the aquifer was not observed in this study. The lack of enhanced attenuation can be attributed to the fact that the anoxic plume, comprised largely of recalcitrant DOC and reduced inorganic constituents, interacted with anoxic slough sediments and porewaters, rather than encountering a change in redox conditions that could cause transformation reactions. Nevertheless, the attenuation processes in the narrow zone of groundwater/surface-water interaction were effective in reducing ammonium concentrations by a factor of about 3 during lateral transport across the slough and by a factor of 2 to 10 before release to the surface water. Slough porewater geochemistry also indicated that the slough could be a source of sulfate in dry conditions, potentially providing a terminal electron acceptor for natural attenuation of organic compounds in the leachate plume.
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Affiliation(s)
- Michelle M Lorah
- U.S. Geological Survey, 5522 Research Park Drive, Baltimore, MD 21228, USA.
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22
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Weiss JV, Cozzarelli IM. Biodegradation in contaminated aquifers: incorporating microbial/molecular methods. GROUND WATER 2008; 46:305-322. [PMID: 18194318 DOI: 10.1111/j.1745-6584.2007.00409.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In order to evaluate natural attenuation in contaminated aquifers, there has been a recent recognition that a multidisciplinary approach, incorporating microbial and molecular methods, is required. Observed decreases in contaminant mass and identified footprints of biogeochemical reactions are often used as evidence of intrinsic bioremediation, but characterizing the structure and function of the microbial populations at contaminated sites is needed. In this paper, we review the experimental approaches and microbial methods that are available as tools to evaluate the controls on microbially mediated degradation processes in contaminated aquifers. We discuss the emerging technologies used in biogeochemical studies and present a synthesis of recent studies that serve as models of integrating microbiological approaches with more traditional geochemical and hydrogeologic approaches in order to address important biogeochemical questions about contaminant fate.
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Affiliation(s)
- Johanna V Weiss
- Biotechnology Program, Northern Virginia Community College, Manassas, VA 20109, USA
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23
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Scholl MA, Cozzarelli IM, Christenson SC. Recharge processes drive sulfate reduction in an alluvial aquifer contaminated with landfill leachate. JOURNAL OF CONTAMINANT HYDROLOGY 2006; 86:239-61. [PMID: 16677736 DOI: 10.1016/j.jconhyd.2006.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 12/23/2005] [Accepted: 03/16/2006] [Indexed: 05/09/2023]
Abstract
Natural attenuation of contaminants in groundwater depends on an adequate supply of electron acceptors to stimulate biodegradation. In an alluvial aquifer contaminated with leachate from an unlined municipal landfill, the mechanism of recharge infiltration was investigated as a source of electron acceptors. Water samples were collected monthly at closely spaced intervals in the top 2 m of the saturated zone from a leachate-contaminated well and an uncontaminated well, and analyzed for delta(18)O, delta(2)H, non-volatile dissolved organic carbon (NVDOC), SO(4)(2-), NO(3)(-) and Cl(-). Monthly recharge amounts were quantified using the offset of the delta(18)O or delta(2)H from the local meteoric water line as a parameter to distinguish water types, as evaporation and methanogenesis caused isotopic enrichment in waters from different sources. Presence of dissolved SO(4)(2-) in the top 1 to 2 m of the saturated zone was associated with recharge; SO(4)(2-) averaged 2.2 mM, with maximum concentrations of 15 mM. Nitrate was observed near the water table at the contaminated site at concentrations up to 4.6 mM. Temporal monitoring of delta(2)H and SO(4)(2-) showed that vertical transport of recharge carried SO(4)(2-) to depths up to 1.75 m below the water table, supplying an additional electron acceptor to the predominantly methanogenic leachate plume. Measurements of delta(34)S in SO(4)(2-) indicated both SO(4)(2-) reduction and sulfide oxidation were occurring in the aquifer. Depth-integrated net SO(4)(2-) reduction rates, calculated using the natural Cl(-) gradient as a conservative tracer, ranged from 7.5x10(-3) to 0.61 mM.d(-1) (over various depth intervals from 0.45 to 1.75 m). Sulfate reduction occurred at both the contaminated and uncontaminated sites; however, median SO(4)(2-) reduction rates were higher at the contaminated site. Although estimated SO(4)(2-) reduction rates are relatively high, significant decreases in NVDOC were not observed at the contaminated site. Organic compounds more labile than the leachate NVDOC may be present in the root zone, and SO(4)(2-) reduction may be coupled to methane oxidation. The results show that sulfur (and possibly nitrogen) redox processes within the top 2 m of the aquifer are directly related to recharge timing and seasonal water level changes in the aquifer. The results suggest that SO(4)(2-) reduction associated with the infiltration of recharge may be a significant factor affecting natural attenuation of contaminants in alluvial aquifers.
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Affiliation(s)
- Martha A Scholl
- U.S. Geological Survey, 431 National Center, Reston, VA 20192, USA.
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24
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Bekins BA, Cozzarelli IM, Curtis GP. A simple method for calculating growth rates of petroleum hydrocarbon plumes. GROUND WATER 2005; 43:817-26. [PMID: 16324003 DOI: 10.1111/j.1745-6584.2005.00093.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Consumption of aquifer Fe(III) during biodegradation of ground water contaminants may result in expansion of a contaminant plume, changing the outlook for monitored natural attenuation. Data from two research sites contaminated with petroleum hydrocarbons show that toluene and xylenes degrade under methanogenic conditions, but the benzene and ethylbenzene plumes grow as aquifer Fe(III) supplies are depleted. By considering a one-dimensional reaction front in a constant unidirectional flow field, it is possible to derive a simple expression for the growth rate of a benzene plume. The method balances the mass flux of benzene with the Fe(III) content of the aquifer, assuming that the biodegradation reaction is instantaneous. The resulting expression shows that the benzene front migration is retarded relative to the ground water velocity by a factor that depends on the concentrations of hydrocarbon and bioavailable Fe(III). The method provides good agreement with benzene plumes at a crude oil study site in Minnesota and a gasoline site in South Carolina. Compared to the South Carolina site, the Minnesota site has 25% higher benzene flux but eight times the Fe(III), leading to about one-sixth the expansion rate. Although it was developed for benzene, toluene, ethylbenzene, and xylenes, the growth-rate estimation method may have applications to contaminant plumes from other persistent contaminant sources.
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25
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Chen L, Nanny MA, Knappe DRU, Wagner TB, Ratasuk N. Chemical characterization and sorption capacity measurements of degraded newsprint from a landfill. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:3542-3550. [PMID: 15296303 DOI: 10.1021/es0305914] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Newsprint samples collected from 12-16 ft (top layer (TNP)), 20-24 ft (middle layer (MNP)), and 32-36 ft (bottom layer (BNP)) below the surface of the Norman Landfill (NLF) were characterized by infrared (IR) spectroscopy, cross-polarization, magic-angle spinning 13C nuclear magnetic resonance (CP-MAS 13C NMR) spectroscopy, and tetramethylammonium hydroxide (TMAH) thermochemolysis gas chromatography/mass spectrometry (GC/MS). The extent of NLF newsprint degradation was evaluated by comparing the chemical composition of NLF newsprint to that of fresh newsprint (FNP) and newsprint degraded in the laboratory under methanogenic conditions (DNP). The O-alkyl/alkyl, cellulose/lignin, and lignin/resin acid ratios showed that BNP was the most degraded, and that all three NLF newsprint samples were more degraded than DNP. 13C NMR and TMAH thermochemolysis data demonstrated selective enrichment of lignin over cellulose, and TMAH thermochemolysis further exhibited selective enrichment of resin acids over lignin. In addition, the crystallinity of cellulose in NLF newsprint samples was significantly lower relative to that of FNP and DNP as shown by 13C NMR spectra. The yield of lignin monomers from TMAH thermochemolysis suggested that hydroxyl groups were removed from the propyl side chain of lignin during the anaerobic decomposition of newsprint in the NLF. Moreover, the vanillyl acid/aldehyde ratio, which successfully describes aerobic lignin degradation, was not a good indicator of the anaerobic degradation of lignin on the basis of the TMAH data. The toluene sorption capacity increased as the degree of newsprint degradation increased or as the O-alkyl/alkyl ratio of newsprint decreased. The results of this study further verified that the sorbent O-alkyl/ alkyl ratio is useful for predicting sorption capacities of natural organic materials for hydrophobic organic contaminants.
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Affiliation(s)
- Lixia Chen
- School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, Oklahoma, USA
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26
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Baun A, Reitzel LA, Ledin A, Christensen TH, Bjerg PL. Natural attenuation of xenobiotic organic compounds in a landfill leachate plume (Vejen, Denmark). JOURNAL OF CONTAMINANT HYDROLOGY 2003; 65:269-91. [PMID: 12935953 DOI: 10.1016/s0169-7722(03)00004-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Demonstration of natural attenuation of xenobiotic organic compounds (XOCs) in landfill leachate plumes is a difficult task and still an emerging discipline within groundwater remediation. One of the early studies was made at the Vejen Landfill in Denmark in the late 1980s, which suggested that natural attenuation of XOCs took place under strongly anaerobic conditions within the first 150 m of the leachate plume. This paper reports on a revisit to the same plume 10 years later. Within the strongly anaerobic part of the plume, 49 groundwater samples were characterized with respect to redox-sensitive species and XOCs. The analytical procedures have been developed further and more compounds and lower detection limits were observed this time. In addition, the samples were screened for degradation intermediates and for toxicity. The plume showed fairly stationary features over the 10-year period except that the XOC level as well as the level of chloride and nonvolatile organic carbon (NVOC) in the plume had decreased somewhat. Most of the compounds studied were subject to degradation in addition to dilution. Exceptions were benzene, the herbicide Mecoprop (MCPP), and NVOC. In the early study, NVOC seemed to degrade in the first part of the plume, but this was no longer the case. Benzyl succinic acid (BSA) was for the first time identified in a leachate plume as a direct indicator, and as the only intermediate of toluene degradation. Toxicity measurements on solid phase-extracted (SPE) samples revealed that toxic compounds not analytically identified were still present in the plume, suggesting that toxicity measurements could be helpful in assessing natural attenuation in leachate plumes.
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Affiliation(s)
- Anders Baun
- Environment Resources DTU, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
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27
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Grossman EL, Cifuentes LA, Cozzarelli IM. Anaerobic methane oxidation in a landfill-leachate plume. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2002; 36:2436-2442. [PMID: 12075801 DOI: 10.1021/es015695y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The alluvial aquifer adjacent to Norman Landfill, OK, provides an excellent natural laboratory for the study of anaerobic processes impacting landfill-leachate contaminated aquifers. We collected groundwaters from a transect of seven multilevel wells ranging in depth from 1.3 to 11 m that were oriented parallel to the flow path. The center of the leachate plume was characterized by (1) high alkalinity and elevated concentrations of total dissolved organic carbon, reduced iron, and methane, and (2) negligible oxygen, nitrate, and sulfate concentrations. Methane concentrations and stable carbon isotope (delta13C) values suggest anaerobic methane oxidation was occurring within the plume and at its margins. Methane delta13C values increased from about -54 per thousand near the source to > -10 per thousand downgradient and at the plume margins. The isotopic fractionation associated with this methane oxidation was -13.6+/-1.0 per thousand. Methane 13C enrichment indicated that 80-90% of the original landfill methane was oxidized over the 210-m transect. First-order rate constants ranged from 0.06 to 0.23 per year, and oxidation rates ranged from 18 to 230 microM/y. Overall, hydrochemical data suggest that a sulfate reducer-methanogen consortium may mediate this methane oxidation. These results demonstrate that natural attenuation through anaerobic methane oxidation can be an important sink for landfill methane in aquifer systems.
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Affiliation(s)
- Ethan L Grossman
- Department of Geology & Geophysics, Texas A & M University, College Station 77843, USA.
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28
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Nanny MA, Ratasuk N. Characterization and comparison of hydrophobic neutral and hydrophobic acid dissolved organic carbon isolated from three municipal landfill leachates. WATER RESEARCH 2002; 36:1572-1584. [PMID: 11996346 DOI: 10.1016/s0043-1354(01)00359-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The acid-precipitated (AP) and acid-soluble (AS) fractions of the combined hydrophobic neutral and hydrophobic acid dissolved organic carbon (DOC) were isolated from leachate collected from three municipal landfills of different age and redox conditions. The AP and the AS combined hydrophobic neutral and hydrophobic acid DOC comprised 6-15% and 51-66%, respectively, of the leachate nonpurgable organic carbon. Elemental analysis, infra-red spectroscopy, 13C CP-MAS nuclear magnetic resonance spectroscopy and dipolar dephasing experiments, and thermochemolysis gas chromatography/mass spectrometry results showed that the AP and AS fractions of hydrophobic neutral and hydrophobic acid DOC are highly aliphatic, with linear and branching moieties, and less oxidized than most terrestrial and aquatic humic substances. Very little, if any, polysaccharide or cellulose, lignin, or cutin components comprise these fractions. It is hypothesized that a majority of the organic carbon in these fractions originates highly branched, cyclic aliphatic organic compounds.
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Affiliation(s)
- Mark A Nanny
- School of Civil Engineering and Environmental Science, University of Oklahoma, Norman 73019, USA.
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