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Shrestha P, Junker T, Fenner K, Hahn S, Honti M, Bakkour R, Diaz C, Hennecke D. Simulation Studies to Explore Biodegradation in Water-Sediment Systems: From OECD 308 to OECD 309. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6856-64. [PMID: 27337495 DOI: 10.1021/acs.est.6b01095] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Studies according to OECD 308 and OECD 309 are performed to simulate the biodegradation of chemicals in water-sediment systems in support of persistence assessment and exposure modeling. However, several shortcomings of OECD 308 have been identified that hamper data evaluation and interpretation, and its relation to OECD 309 is still unclear. The present study systematically compares OECD 308 and OECD 309 and two variants thereof to derive recommendations on how to experimentally address any shortcomings and improve data for persistence and risk assessment. To this end, four (14)C-labeled compounds with different biodegradation and sorption behavior were tested across standard OECD 308 and 309 test systems and two modified versions thereof. The well-degradable compounds showed slow equilibration and the least mineralization in OECD 308, whereas the modified systems provided the highest degree of mineralization. Different lines of evidence suggest that this was due to increased oxygenation of the sediment in the modified systems. Particularly for rapidly degrading compounds, non-extractable residue formation was in line with degradation and did not follow the sediment-water ratio. For the two more slowly degrading compounds, sorption in OECD 309 (standard and modified) increased with time beyond levels proposed by equilibrium partitioning, which could be attributed to the grinding of the sediment through the stirring of the sediment suspension. Overall, the large differences in degradation observed across the four test systems suggest that refined specifications in test guidelines are required to reduce variability in test outcomes. At the same time, the amount of sediment and its degree of oxygenation emerged as drivers across all test systems. This suggests that a unified description of the systems was possible and would pave the way toward a more consistent consideration of degradation in the water-sediment systems across different exposure situations and regulatory frameworks.
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Affiliation(s)
- Prasit Shrestha
- Fraunhofer IME-AE , Auf dem Aberg 1, 57392 Schmallenberg, Germany
| | - Thomas Junker
- ECT Oekotoxikologie GmbH , Böttgerstrasse 2-14, 65439 Flörsheim am Main, Germany
| | - Kathrin Fenner
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Stefan Hahn
- Fraunhofer ITEM , Nikolai-Fuchs-Strasse 1, 30625 Hannover, Germany
| | - Mark Honti
- MTA-BME Water Research Group, Hungarian Academy of Sciences , Mügyetem rkp. 3, 1111 Budapest, Hungary
| | - Rani Bakkour
- Eawag, Swiss Federal Institute of Aquatic Science and Technology , Überlandstrasse 133, 8600 Dübendorf, Switzerland
| | - Cecilia Diaz
- Fraunhofer IME-AE , Auf dem Aberg 1, 57392 Schmallenberg, Germany
| | - Dieter Hennecke
- Fraunhofer IME-AE , Auf dem Aberg 1, 57392 Schmallenberg, Germany
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52
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Poßberg C, Schmidt B, Nowak K, Telscher M, Lagojda A, Schaeffer A. Quantitative Identification of Biogenic Nonextractable Pesticide Residues in Soil by (14)C-Analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:6415-6422. [PMID: 27192605 DOI: 10.1021/acs.est.6b00689] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Quantification of nonextractable residues (NER) of pesticides in soil is feasible by use of radioactively labeled compounds, but structural information on these long-term stabilized residues is usually lacking. Microorganisms incorporate parts of the radiolabeled ((14)C-) carbon from contaminants into microbial biomass, which after cell death enters soil organic matter, thus forming biogenic nonextractable residues (bioNER). The formation of bioNER is not yet determinable in environmental fate studies due to a lack of methodology. This paper focuses on the development of a feasible analytical method to quantify proteinaceous carbon, since proteins make up the largest mass portion of bacterial cells. The test substance (14)C-bromoxynil after 56 days forms more than 70% of NER in soil. For further characterization of NER the amino acids were extracted, purified, and separated by two-dimensional thin-layer chromatography (TLC). Visualization of the (14)C-amino acids was performed by bioimaging, unambiguous identification by GC-MS and LC-MS/MS. Our analysis revealed that after 56 days of incubation about 14.5% of the (14)C-label of bromoxynil was incorporated in amino acids. Extrapolating this content based on the amount of proteins in the biomass (55%), in total about 26% of the NER is accounted for by bioNER and thus is not environmentally relevant.
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Affiliation(s)
- Claudia Poßberg
- RWTH Aachen University , Institute for Environmental Research (Biology 5), Worringer Weg 1, 52074 Aachen, Germany
| | - Burkhard Schmidt
- RWTH Aachen University , Institute for Environmental Research (Biology 5), Worringer Weg 1, 52074 Aachen, Germany
| | - Karolina Nowak
- RWTH Aachen University , Institute for Environmental Research (Biology 5), Worringer Weg 1, 52074 Aachen, Germany
- Helmholtz-Centre for Environmental Research - UFZ , Department of Environmental Biotechnology, 04318 Leipzig, Germany
| | - Markus Telscher
- Bayer CropScience AG, Alfred-Nobel-Str. 50, 40789 Monheim am Rhein, Germany
| | - Andreas Lagojda
- Bayer CropScience AG, Alfred-Nobel-Str. 50, 40789 Monheim am Rhein, Germany
| | - Andreas Schaeffer
- RWTH Aachen University , Institute for Environmental Research (Biology 5), Worringer Weg 1, 52074 Aachen, Germany
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing 210093, P. R. China
- College of Resources and Environmental Science, Chongqing University , Chongqing 400030, P. R. China
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Cassigneul A, Benoit P, Bergheaud V, Dumeny V, Etiévant V, Goubard Y, Maylin A, Justes E, Alletto L. Fate of glyphosate and degradates in cover crop residues and underlying soil: A laboratory study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 545-546:582-90. [PMID: 26760277 DOI: 10.1016/j.scitotenv.2015.12.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 12/11/2015] [Accepted: 12/11/2015] [Indexed: 06/05/2023]
Abstract
The increasing use of cover crops (CC) may lead to an increase in glyphosate application for their destruction. Sorption and degradation of (14)C-glyphosate on and within 4 decaying CC-amended soils were compared to its fate in a bare soil. (14)C-Glyphosate and its metabolites distribution between mineralized, water-soluble, NH4OH-soluble and non-extractable fractions was determined at 5 dates during a 20 °C/84-d period. The presence of CC extends (14)C-glyphosate degradation half-life from 7 to 28 days depending on the CC. (14)C-Glyphosate dissipation occurred mainly through mineralization in soils and through mineralization and bound residue formation in decaying CC. Differences in sorption and degradation levels were attributed to differences in composition and availability to microorganisms. CC- and soil-specific dissipation patterns were established with the help of explicit relationships between extractability and microbial activity.
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Affiliation(s)
- A Cassigneul
- Université de Toulouse - École d'ingénieurs de Purpan, UMR 1248 AGIR - 75, Voie du TOEC BP 57 611, 31 076, Toulouse cedex 3, France; INRA, UMR 1402 ECOSYS, 78850 Thiverval-Grignon, France
| | - P Benoit
- INRA, UMR 1402 ECOSYS, 78850 Thiverval-Grignon, France
| | - V Bergheaud
- INRA, UMR 1402 ECOSYS, 78850 Thiverval-Grignon, France
| | - V Dumeny
- INRA, UMR 1402 ECOSYS, 78850 Thiverval-Grignon, France
| | - V Etiévant
- INRA, UMR 1402 ECOSYS, 78850 Thiverval-Grignon, France
| | - Y Goubard
- AgroParisTech, UMR 1402 ECOSYS, 78850 Thiverval-Grignon, France
| | - A Maylin
- Université de Toulouse - École d'ingénieurs de Purpan, UMR 1248 AGIR - 75, Voie du TOEC BP 57 611, 31 076, Toulouse cedex 3, France
| | - E Justes
- INRA, UMR 1248 AGIR Auzeville - BP 52 627, 31 326, Castanet-Tolosan cedex, France
| | - L Alletto
- Université de Toulouse - École d'ingénieurs de Purpan, UMR 1248 AGIR - 75, Voie du TOEC BP 57 611, 31 076, Toulouse cedex 3, France
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54
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Saleh O, Pagel H, Enowashu E, Devers M, Martin-Laurent F, Streck T, Kandeler E, Poll C. Evidence for the importance of litter as a co-substrate for MCPA dissipation in an agricultural soil. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:4164-4175. [PMID: 25943518 DOI: 10.1007/s11356-015-4633-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/28/2015] [Indexed: 06/04/2023]
Abstract
Environmental controls of 2-methyl-4-chlorophenoxyacetic acid (MCPA) degradation are poorly understood. We investigated whether microbial MCPA degraders are stimulated by (maize) litter and whether this process depends on concentrations of MCPA and litter. In a microcosm experiment, different amounts of litter (0, 10 and 20 g kg(-1)) were added to soils exposed to three levels of the herbicide (0, 5 and 30 mg kg(-1)). The treated soils were incubated at 20 °C for 6 weeks, and samples were taken after 1, 3 and 6 weeks of incubation. In soils with 5 mg kg(-1) MCPA, about 50 % of the MCPA was dissipated within 1 week of the incubation. Almost complete dissipation of the herbicide had occurred by the end of the incubation with no differences between the three litter amendments. At the higher concentration (30 mg kg(-1)), MCPA endured longer in the soil, with only 31 % of the initial amount being removed at the end of the experiment in the absence of litter. Litter addition greatly increased the dissipation rate with 70 and 80 % of the herbicide being dissipated in the 10 and 20 g kg(-1) litter treatments, respectively. Signs of toxic effects of MCPA on soil bacteria were observed from related phospholipid fatty acid (PLFA) analyses, while fungi showed higher tolerance to the increased MCPA levels. The abundance of bacterial tfdA genes in soil increased with the co-occurrence of litter and high MCPA concentration, indicating the importance of substrate availability in fostering MCPA-degrading bacteria and thereby improving the potential for removal of MCPA in the environment.
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Affiliation(s)
- Omar Saleh
- Institute of Soil Science and Land Evaluation, Soil Biology, University of Hohenheim, Emil-Wolff-Str. 27, D-70593, Stuttgart, Germany
- Department of Biology and Biochemistry, Birzeit University, P.O. Box 14, Birzeit, West Bank, Palestine
| | - Holger Pagel
- Institute of Soil Science and Land Evaluation, Biogeophysics, University of Hohenheim, Emil-Wolff-Str. 27, D-70593, Stuttgart, Germany
| | - Esther Enowashu
- Institute of Soil Science and Land Evaluation, Soil Biology, University of Hohenheim, Emil-Wolff-Str. 27, D-70593, Stuttgart, Germany
| | - Marion Devers
- INRA, UMR 1347 Agroécologie, 17 Rue Sully, BP 8 6510, F-21065, Dijon, Cedex, France
| | | | - Thilo Streck
- Institute of Soil Science and Land Evaluation, Biogeophysics, University of Hohenheim, Emil-Wolff-Str. 27, D-70593, Stuttgart, Germany
| | - Ellen Kandeler
- Institute of Soil Science and Land Evaluation, Soil Biology, University of Hohenheim, Emil-Wolff-Str. 27, D-70593, Stuttgart, Germany
| | - Christian Poll
- Institute of Soil Science and Land Evaluation, Soil Biology, University of Hohenheim, Emil-Wolff-Str. 27, D-70593, Stuttgart, Germany.
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55
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Mukherjee S, Tappe W, Weihermueller L, Hofmann D, Köppchen S, Laabs V, Schroeder T, Vereecken H, Burauel P. Dissipation of bentazone, pyrimethanil and boscalid in biochar and digestate based soil mixtures for biopurification systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 544:192-202. [PMID: 26657365 DOI: 10.1016/j.scitotenv.2015.11.111] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/09/2015] [Accepted: 11/23/2015] [Indexed: 06/05/2023]
Abstract
Biopurification systems, such as biofilters, are biotechnological tools to prevent point sources of pesticide pollution stemming from on-farm operations. For the purification processes pesticide sorption and mineralization and/or dissipation are essential and both largely depend on the type of filling materials and the pesticide in use. In this paper the mineralization and dissipation of three contrasting (14)C-labeled pesticides (bentazone, boscalid, and pyrimethanil) were investigated in laboratory incubation experiments using sandy soil, biochar produced from Pine woodchips, and/or digestate obtained from anaerobic digestion process using maize silage, chicken manure, beef and pig urine as feedstock. The results indicate that the addition of digestate increased pesticide mineralization, whereby the mineralization was not proportional to the digestate loads in the mixture, indicating a saturation effect in the turnover rate of pesticides. This effect was in correlation with the amount of water extractable DOC, obtained from the digestate based mixtures. Mixing biochar into the soil generally reduced total mineralization and led to larger sorption/sequestration of the pesticides, resulting in faster decrease of the extractable fraction. Also the addition of biochar to the soil/digestate mixtures reduced mineralization compared to the digestate alone mixture but mineralization rates were still higher as for the biochar/soil alone. In consequence, the addition of biochar to the soil generally decreased pesticide dissipation times and larger amounts of biochar led to high amounts of non-extractable residues of pesticide in the substrates. Among the mixtures tested, a mixture of digestate (5%) and biochar (5%) gave optimal results with respect to mineralization and simultaneous sorption for all three pesticides.
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Affiliation(s)
- Santanu Mukherjee
- Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
| | - Wolfgang Tappe
- Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Lutz Weihermueller
- Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Diana Hofmann
- Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Stephan Köppchen
- Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Volker Laabs
- BASF SE, Crop Protection, 67117, Limburgerhof, Germany
| | - Tom Schroeder
- BASF SE, Crop Protection, 67117, Limburgerhof, Germany
| | - Harry Vereecken
- Institute of Bio- and Geosciences (IBG-3), Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Peter Burauel
- Sustainable Campus, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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56
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Paszko T, Muszyński P, Materska M, Bojanowska M, Kostecka M, Jackowska I. Adsorption and degradation of phenoxyalkanoic acid herbicides in soils: A review. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2016; 35:271-86. [PMID: 26292078 DOI: 10.1002/etc.3212] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/04/2015] [Accepted: 08/14/2015] [Indexed: 05/23/2023]
Abstract
The primary aim of the present review on phenoxyalkanoic acid herbicides-2-(2,4-dichlorophenoxy) acetic acid (2,4-D), 2-(4-chloro-2-methylphenoxy) acetic acid (MCPA), (2R)-2-(2,4-dichlorophenoxy) propanoic acid (dichlorprop-P), (2R)-2-(4-chloro-2-methylphenoxy) propanoic acid (mecoprop-P), 4-(2,4-dichlorophenoxy) butanoic acid (2,4-DB), and 4-(4-chloro-2-methylphenoxy) butanoic acid (MCPB)-was to compare the extent of their adsorption in soils and degradation rates to assess their potential for groundwater contamination. The authors found that adsorption decreased in the sequence of 2,4-DB > 2,4-D > MCPA > dichlorprop-P > mecoprop-P. Herbicides are predominantly adsorbed as anions-on organic matter and through a water-bridging mechanism with adsorbed Fe cations-and their neutral forms are adsorbed mainly on organic matter. Adsorption of anions of 2,4-D, MCPA, dichlorprop-P, and mecoprop-P is inversely correlated with their lipophilicity values, and modeling of adsorption of the compounds based on this relationship is possible. The predominant dissipation mechanism of herbicides in soils is bacterial degradation. The contribution of other mechanisms, such as degradation by fungi, photodegradation, or volatilization from soils, is much smaller. The rate of bacterial degradation decreased in the following order: 2,4-D > MCPA > mecoprop-P > dichlorprop-P. It was found that 2,4-D and MCPA have the lowest potential for leaching into groundwater and that mecoprop-P and dichlorprop-P have slightly higher potential. Because of limited data on adsorption and degradation of 2,4-DB and MCPB, estimation of their leaching potential was not possible.
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Affiliation(s)
- Tadeusz Paszko
- Department of Chemistry, University of Life Sciences, Lublin, Poland
| | - Paweł Muszyński
- Department of Chemistry, University of Life Sciences, Lublin, Poland
| | | | - Monika Bojanowska
- Department of Chemistry, University of Life Sciences, Lublin, Poland
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57
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Aleksandrova ON, Kholodov VA, Perminova IV. Using spin labels to study molecular processes in soils: Covalent binding of aromatic amines to humic acids of soils. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2015. [DOI: 10.1134/s0036024415080038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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58
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Degradation of 13C-labeled pyrene in soil-compost mixtures and fertilized soil. Appl Microbiol Biotechnol 2015. [DOI: 10.1007/s00253-015-6822-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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59
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Im J, Prevatte CW, Lee HG, Campagna SR, Löffler FE. 4-methylphenol produced in freshwater sediment microcosms is not a bisphenol A metabolite. CHEMOSPHERE 2014; 117:521-526. [PMID: 25268077 DOI: 10.1016/j.chemosphere.2014.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 08/31/2014] [Accepted: 09/02/2014] [Indexed: 06/03/2023]
Abstract
4-Methylphenol (4-MP), a putative bisphenol A (BPA) degradation intermediate, was detected at concentrations reaching 2.1 mg L(-1) in anoxic microcosms containing 10 mg L(-1) BPA and 5 g of freshwater sediment material collected from four geographically distinct locations and amended with nitrate, nitrite, ferric iron, or bicarbonate as electron acceptors. 4-MP accumulation was transient, and 4-MP degradation was observed under all redox conditions tested. 4-MP was not detected in microcosms not amended with BPA. Unexpectedly, incubations with (13)C-labeled BPA failed to produce (13)C-labeled 4-MP suggesting that 4-MP was not derived from BPA. The detection of 4-MP in live microcosms amended with lactate, but not containing BPA corroborated that BPA was not the source of 4-MP. These findings demonstrate that the transient formation of 4-MP as a possible BPA degradation intermediate must be interpreted cautiously, as microbial activity in streambed microcosms may generate 4-MP from sediment-associated organic material.
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Affiliation(s)
- Jeongdae Im
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States; Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN 37996, United States
| | - Carson W Prevatte
- Department of Chemistry, The University of Tennessee, Knoxville, TN 37996, United States
| | - Hong Geun Lee
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Shawn R Campagna
- Department of Chemistry, The University of Tennessee, Knoxville, TN 37996, United States
| | - Frank E Löffler
- Department of Microbiology, University of Tennessee, Knoxville, TN 37996, United States; Center for Environmental Biotechnology, University of Tennessee, Knoxville, TN 37996, United States; Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996, United States; University of Tennessee and Oak Ridge National Laboratory (UT-ORNL) Joint Institute for Biological Sciences (JIBS) and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
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60
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Ogbonnaya OU, Adebisi OO, Semple KT. The impact of biochar on the bioaccessibility of (14)C-phenanthrene in aged soil. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2014; 16:2635-2643. [PMID: 25277257 DOI: 10.1039/c4em00396a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Biochar is a carbon rich product from the incomplete combustion of biomass and it has been shown to reduce bioavailability of organic contaminants through adsorption. This study investigated the influence of 0%, 1%, 5% and 10% of two different particle sized wood biochars (≤2 mm and 3-7 mm) on the bioaccessibility of (14)C-phenanthrene (10 mg kg(-1)) in aged soil. The extent of (14)C-phenanthrene mineralisation by phenanthrene-degrading Pseudomonas sp. inoculum was monitored over a 14 day period in respirometric assays and compared to hydroxypropyl-β-cyclodextrin (HPCD) aqueous extraction. Notably, biochar amendments showed significant reduction in extents of mineralisation and HPCD extraction. Linear correlations between HPCD extractability and the total amount mineralised revealed good correlations, with 2 mm biochar showing a best fit (r(2) = 0.97, slope = 1.11, intercept = 1.72). Biochar reduced HPCD extractability and bioaccessibility of (14)C-phenanthrene to microorganisms in a similar manner. Biochar can aid risk reduction to phenanthrene exposure to biota in soil and HPCD can serve as a useful tool to assess the extent of exposure in biochar-amended soils.
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Affiliation(s)
- O U Ogbonnaya
- EcoSystems Environmental Management Services Ltd, 8 Rasheed Alaba Williams Street, Off Admiralty Way, Lekki Peninsula, Lagos, Nigeria.
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61
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Pajares A, Bregliani M, Massad W, Natera J, Challier C, Boiero L, Montenegro M, García NA. On the natural fate of maleic hydrazide. Kinetic aspects of the photochemical and microbiological degradation of the herbicide. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 135:48-54. [DOI: 10.1016/j.jphotobiol.2014.04.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 03/05/2014] [Accepted: 04/07/2014] [Indexed: 11/28/2022]
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Hedegaard MJ, Albrechtsen HJ. Microbial pesticide removal in rapid sand filters for drinking water treatment--potential and kinetics. WATER RESEARCH 2014; 48:71-81. [PMID: 24112625 DOI: 10.1016/j.watres.2013.09.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 09/06/2013] [Accepted: 09/07/2013] [Indexed: 06/02/2023]
Abstract
Filter sand samples, taken from aerobic rapid sand filters used for treating groundwater at three Danish waterworks, were investigated for their pesticide removal potential and to assess the kinetics of the removal process. Microcosms were set up with filter sand, treated water, and the pesticides or metabolites mecoprop (MCPP), bentazone, glyphosate and p-nitrophenol were applied in initial concentrations of 0.03-2.4 μg/L. In all the investigated waterworks the concentration of pesticides in the water decreased - MCPP decreased to 42-85%, bentazone to 15-35%, glyphosate to 7-14% and p-nitrophenol 1-3% - from the initial concentration over a period of 6-13 days. Mineralisation of three out of four investigated pesticides was observed at Sjælsø waterworks Plant II - up to 43% of the initial glyphosate was mineralised within six days. At Sjælsø waterworks Plant II the removal kinetics of bentazone revealed that less than 30 min was needed to remove 50% of the bentazone at all the tested initial concentrations (0.1-2.4 μg/L). Increased oxygen availability led to greater and faster removal of bentazone in the microcosms. After 1 h, bentazone removal (an initial bentazone concentration of 0.1 μg/L) increased from 0.21%/g filter sand to 0.75%/g filter sand, when oxygen availability was increased from 0.28 mg O2/g filter sand to 1.09 mg O2/g filter sand. Bentazone was initially cleaved in the removal process. A metabolite, which contained the carbonyl group, was removed rapidly from the water phase and slowly mineralised after 24 h, while a metabolite which contained the benzene-ring was still present in the water phase. However, the microbial removal of this metabolite was initiated over seven days.
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Affiliation(s)
- Mathilde J Hedegaard
- DTU Environment, Technical University of Denmark, Building 113, DK-2800 Kgs. Lyngby, Denmark.
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Marchal G, Smith KEC, Rein A, Winding A, Wollensen de Jonge L, Trapp S, Karlson UG. Impact of activated carbon, biochar and compost on the desorption and mineralization of phenanthrene in soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 181:200-210. [PMID: 23871817 DOI: 10.1016/j.envpol.2013.06.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 06/16/2013] [Accepted: 06/17/2013] [Indexed: 06/02/2023]
Abstract
Sorption of PAHs to carbonaceous soil amendments reduces their dissolved concentrations, limiting toxicity but also potentially biodegradation. Therefore, the maximum abiotic desorption of freshly sorbed phenanthrene (≤5 mg kg(-1)) was measured in three soils amended with activated carbon (AC), biochar or compost. Total amounts of phenanthrene desorbed were similar between the different soils, but the amendment type had a large influence. Complete desorption was observed in the unamended and compost amended soils, but this reduced for biochar (41% desorbed) and AC (8% desorbed). Cumulative amounts mineralized were 28% for the unamended control, 19% for compost, 13% for biochar and 4% for AC. Therefore, the effects of the amendments in soil in reducing desorption were also reflected in the extents of mineralization. Modeling was used to analyze key processes, indicating that for the AC and charcoal treatments bacterial activity did not limit mineralization, but rather desorption into the dissolved phase.
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Affiliation(s)
- Geoffrey Marchal
- Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
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Liu J, Wang Y, Jiang B, Wang L, Chen J, Guo H, Ji R. Degradation, metabolism, and bound-residue formation and release of Tetrabromobisphenol A in soil during sequential anoxic-oxic incubation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8348-8354. [PMID: 23834753 DOI: 10.1021/es4014322] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Tetrabromobisphenol A (TBBPA) is one of the most commonly used flame retardants and has become an environmental contaminant worldwide. We studied the fate of (14)C-labeled TBBPA in soil under static anoxic (195 days) and sequential anoxic (125 days)-oxic (70 days) conditions. During anoxic incubation, TBBPA dissipated with a half-life of 36 days, yielding four debromination metabolites: bisphenol A (BPA) and mono-, di-, and tribrominated BPA. At the end of anoxic incubation, all four brominated BPAs completely disappeared, leaving BPA (54% of initial TBBPA) as the sole detectable organic metabolite. TBBPA dissipation was accompanied by trace mineralization (<1.3%) and substantial bound-residue formation (35%), probably owing to chemical binding to soil organic matter. Subsequent oxic incubation was effective in degrading accumulated BPA (half-life 11 days) through mineralization (6%) and bound-residue formation (62%). However, 42% of the anoxically formed bound residues was released as TBBPA and lower brominated BPAs, which were then persistent during oxic incubation. Our results provide the first evidence for release of bound residues during alteration of the redox environment and indicate that sequential anoxic-oxic incubation approaches-considered effective in remediation of environments containing halogenated xenobiotics-do not completely remove xenobiotics from environmental matrices.
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Affiliation(s)
- Jie Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Xianlin Avenue 163, 210023 Nanjing, China
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Johnsen AR, Binning PJ, Aamand J, Badawi N, Rosenbom AE. The gompertz function can coherently describe microbial mineralization of growth-sustaining pesticides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:8508-14. [PMID: 23796023 DOI: 10.1021/es400861v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Mineralization of (14)C-labeled tracers is a common way of studying the environmental fate of xenobiotics, but it can be difficult to extract relevant kinetic parameters from such experiments since complex kinetic functions or several kinetic functions may be needed to adequately describe large data sets. In this study, we suggest using a two-parameter, sigmoid Gompertz function for parametrizing mineralization curves. The function was applied to a data set of 252 normalized mineralization curves that represented the potential for degradation of the herbicide MCPA in three horizons of an agricultural soil. The Gompertz function fitted most of the normalized curves, and trends in the data set could be visualized by a scatter plot of the two Gompertz parameters (rate constant and time delay). For agricultural topsoil, we also tested the effect of the MCPA concentration on the mineralization kinetics. Reduced initial concentrations lead to shortened lag-phases, probably due to reduced need for bacterial growth. The effect of substrate concentration could be predicted by simply changing the time delay of the Gompertz curves. This delay could to some extent also simulate concentration effects for 2,4-D mineralization in agricultural soil and aquifer sediment and 2,6-dichlorobenzamide mineralization in single-species, mineral medium.
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Affiliation(s)
- Anders R Johnsen
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS) , Øster Voldgade 10, DK-1350 Copenhagen K, Denmark.
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66
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Dallinger A, Horn MA. Agricultural soil and drilosphere as reservoirs of new and unusual assimilators of 2,4-dichlorophenol carbon. Environ Microbiol 2013; 16:84-100. [DOI: 10.1111/1462-2920.12209] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 07/08/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Anja Dallinger
- Department of Ecological Microbiology; University of Bayreuth; Dr.-Hans-Frisch-Straße 1-3 Bayreuth 95440 Germany
| | - Marcus A. Horn
- Department of Ecological Microbiology; University of Bayreuth; Dr.-Hans-Frisch-Straße 1-3 Bayreuth 95440 Germany
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Riefer P, Klausmeyer T, Adams A, Schmidt B, Schäffer A, Schwarzbauer J. Incorporation mechanisms of a branched nonylphenol isomer in soil-derived organo-clay complexes during a 180-day experiment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:7155-7162. [PMID: 23713749 DOI: 10.1021/es304579s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The incorporation process of a defined (13)C- and (14)C-labeled nonylphenol isomer (4-(3,5-dimethylhept-3-yl)phenol) into soil-derived organo-clay complexes was investigated. Isolated organo-clay complexes were separated into humic subfractions. Noninvasive ((13)C-CP/MAS NMR) and invasive methods (sequential chemical degradation, pyrolysis) were applied to obtain detailed information about the mode of incorporation, chemical structure, and change of the incorporation character of nonextractable residues in course of incubation. (13)C-CP/MAS NMR measurements of humic acids revealed an increasing incorporation of phenolic compounds during the experimental time which was referred to residues of the introduced (13)C-labeled NP isomer. Detailed investigations by means of sequential chemical degradation indicated a predominant incorporation of nonextractable NP isomer residues via reversible ester (amide) bonds. In course of time, the amount of releasable compounds decreased, pointing to altering processes which affected the mode of incorporation. BBr3-treatment, RuO4 oxidation, and thermochemolysis released only low portions of nonextractable radioactivity giving evidence of strongly incorporated residues. With the comprehensive application of complementary methods (e.g., humic matter fractionation, (13)C-CP/MAS NMR, sequential chemical degradation) it was possible to provide a comparatively detailed insight into the incorporation behavior of the applied NP isomer.
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Affiliation(s)
- Patrick Riefer
- Institute of Geology and Geochemistry of Petroleum and Coal, RWTH Aachen University, Aachen, Germany
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68
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Nowak KM, Girardi C, Miltner A, Gehre M, Schäffer A, Kästner M. Contribution of microorganisms to non-extractable residue formation during biodegradation of ibuprofen in soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 445-446:377-384. [PMID: 23361042 DOI: 10.1016/j.scitotenv.2012.12.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 12/05/2012] [Accepted: 12/05/2012] [Indexed: 06/01/2023]
Abstract
Non-extractable residues (NER) formed during biodegradation of organic contaminants in soil are considered to be mainly composed of parent compounds or their primary metabolites with hazardous potential. However, in the case of biodegradable organic compounds, the soil NER may also contain microbial biomass components, for example fatty acids (FA) and amino acids (AA). After cell death, these biomolecules are subsequently incorporated into non-living soil organic matter (SOM) and are stabilised ultimately forming hardly extractable residues of biogenic origin. We investigated biodegradation of (13)C(6)-ibuprofen, in particular the metabolic incorporation of the (13)C-label into FA and AA and their fate in soil over 90 days. (13)C-FA and (13)C-AA amounts in the living microbial biomass fraction initially increased, then decreased over time and were continuously incorporated into the non-living SOM pool. The (13)C-FA in the non-living SOM remained stable from day 59 whereas the contents of (13)C-AA slightly increased until the end. After 90 days, nearly all NER were biogenic as they were made up almost completely by natural biomass compounds. The presented data demonstrated that the potential environmental risks related to the ibuprofen-derived NER are overestimated.
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Affiliation(s)
- Karolina M Nowak
- UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstrasse 15, 04318 Leipzig, Germany.
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69
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Girardi C, Nowak KM, Carranza-Diaz O, Lewkow B, Miltner A, Gehre M, Schäffer A, Kästner M. Microbial degradation of the pharmaceutical ibuprofen and the herbicide 2,4-D in water and soil - use and limits of data obtained from aqueous systems for predicting their fate in soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 444:32-42. [PMID: 23262323 DOI: 10.1016/j.scitotenv.2012.11.051] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 11/13/2012] [Accepted: 11/13/2012] [Indexed: 06/01/2023]
Abstract
The persistence of chemicals is a key parameter for their environmental risk assessment. Extrapolating their biodegradability potential in aqueous systems to soil systems would improve the environmental impact assessment. This study compares the fate of (14/13)C-labelled 2,4-D (2,4-dichlorophenoxyacetic acid) and ibuprofen in OECD tests 301 (ready biodegradability in aqueous systems) and 307 (soil). 85% of 2,4-D and 68% of ibuprofen were mineralised in aqueous systems, indicating ready biodegradability, but only 57% and 45% in soil. Parent compounds and metabolites decreased to <2% of the spiked amounts in both systems. In soil, 36% of 2,4-D and 30% of ibuprofen were bound in non-extractable residues (NER). NER formation in the abiotic controls was half as high as in the biotic treatments. However, mineralisation, biodegradation and abiotic residue formation are competing processes. Assuming the same extent of abiotic NER formation in abiotic and biotic systems may therefore overestimate the abiotic contribution in the biotic systems. Mineralisation was described by a logistic model for the aquatic systems and by a two-pool first order degradation model for the soil systems. This agrees with the different abundance of microorganisms in the two systems, but precludes direct comparison of the fitted parameters. Nevertheless, the maximum mineralisable amounts determined by the models were similar in both systems, although the maximum mineralisation rate was about 3.5 times higher in the aqueous systems than in the soil system for both compounds; these parameters may thus be extrapolated from aqueous to soil systems. However, the maximum mineralisable amount is calculated by extrapolation to infinite times and includes intermediately formed biomass derived from the labelled carbon. The amount of labelled carbon within microbial biomass residues is higher in the soil system, resulting in lower degradation rates. Further evaluation of these relationships requires comparison data on more chemicals and from different soils.
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Affiliation(s)
- Cristobal Girardi
- UFZ - Helmholtz Centre for Environmental Research, Department of Environmental Biotechnology, Permoserstraße 15, 04318 Leipzig, Germany.
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Niedrée B, Vereecken H, Burauel P. Radiation-induced impacts on the degradation of 2,4-D and the microbial population in soil microcosms. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 115:168-174. [PMID: 22975652 DOI: 10.1016/j.jenvrad.2012.08.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 08/07/2012] [Accepted: 08/12/2012] [Indexed: 06/01/2023]
Abstract
In a soil microcosm experiment, the influence of low-level (137)Cs and (90)Sr contamination on the degradation of (14)C-ring-labeled 2,4-dichlorophenoxyacetic acid (2,4-D) was studied. Two differently treated soils (one native soil and one soil sterilized and reinoculated with a biotic soil aliquot) were artificially contaminated with various concentrations of (137)Cs and (90)Sr as nitrate salts. The cumulative doses increased up to 4 Gy for 30 days of incubation in soil microcosms. Changes in microbial community structure were observed with help of the denaturing gradient gel electrophoresis (DGGE). A radiation-induced impact appeared only in the microcosms treated with 30 times the maximum contamination appearing in the exclusion zone around reactor 4 in Chernobyl. In contrast to the less contaminated soils, the mineralization of 2,4-D was delayed for 4 days before it recovered. Slight shifts in the microbial communities could be traced to radiation effects. However, other parameters had a major impact on mineralization and community structure. Thus the sterilization and reinoculation and, of course, application of the 2,4-D were predominantly reflected in the (14)CO(2) emissions and the DGGE gel patterns.
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Affiliation(s)
- Bastian Niedrée
- Agrosphere Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
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71
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Zhou W, Shan J, Jiang B, Wang L, Feng J, Guo H, Ji R. Inhibitory effects of carbon nanotubes on the degradation of 14C-2,4-dichlorophenol in soil. CHEMOSPHERE 2013; 90:527-534. [PMID: 22963879 DOI: 10.1016/j.chemosphere.2012.08.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 07/19/2012] [Accepted: 08/07/2012] [Indexed: 06/01/2023]
Abstract
Concerns on the potential risks of engineered nanoparticles to the environment are increasing; however, little is known about the effects of carbon nanotubes (CNTs) on the environmental fate of hydrophobic organic pollutants in soil. We incubated radioactive labeled 2,4-dichlorophenol ((14)C-2,4-DCP) in a soil in the presence of various concentrations (0, 2, 20, and 2000 mg kg(-1) dry soil) of single-walled (SWCNTs) and multi-walled (MWCNTs) carbon nanotubes, and determined the mineralization, degradation, and residue distribution of 2,4-DCP in the soil. CNTs were added to the soil either after the spiking of (14)C-2,4-DCP or together with (14)C-2,4-DCP as a mixture. CNTs at the concentration of 2000 mg kg(-1) significantly (P<0.05) inhibited the mineralization of (14)C-2,4-DCP and induced a 2.3- to 3.9-fold increase in the amounts of the non-degraded (14)C-2,4-DCP in the soil after 90 d of incubation. Pre-adsorption of (14)C-2,4-DCP on CNTs showed stronger inhibitory effects on the degradation of (14)C-2,4-DCP, already significant with CNTs at 20 mg kg(-1). In general, SWCNTs had a higher effect on the degradation and residue distribution of 2,4-DCP in the soil than MWCNTs. The inhibitory effects are supposed to be owing to limited activities of soil endogenous microorganisms, potential toxicities of CNTs to the microorganisms, and reduced bioavailability of 2,4-DCP in the presence of CNTs, even though a desorption hysteresis of 2,4-DCP on CNTs was not observed. Our results indicate that CNTs have more significant impacts on the environmental fate of the hydrophobic pollutants entering soil together with CNTs via strong sorption than the pollutants already present in soil.
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Affiliation(s)
- Wenqiang Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163 Xianlin Avenue, Nanjing 210046, China
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72
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Loos M, Krauss M, Fenner K. Pesticide nonextractable residue formation in soil: insights from inverse modeling of degradation time series. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:9830-9837. [PMID: 22891938 DOI: 10.1021/es300505r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Formation of soil nonextractable residues (NER) is central to the fate and persistence of pesticides. To investigate pools and extent of NER formation, an established inverse modeling approach for pesticide soil degradation time series was evaluated with a Monte Carlo Markov Chain (MCMC) sampling procedure. It was found that only half of 73 pesticide degradation time series from a homogeneous soil source allowed for well-behaved identification of kinetic parameters with a four-pool model containing a parent compound, a metabolite, a volatile, and a NER pool. A subsequent simulation indeed confirmed distinct parameter combinations of low identifiability. Taking the resulting uncertainties into account, several conclusions regarding NER formation and its impact on persistence assessment could nonetheless be drawn. First, rate constants for transformation of parent compounds to metabolites were correlated to those for transformation of parent compounds to NER, leading to degradation half-lives (DegT50) typically not being larger than disappearance half-lives (DT50) by more than a factor of 2. Second, estimated rate constants were used to evaluate NER formation over time. This showed that NER formation, particularly through the metabolite pool, may be grossly underestimated when using standard incubation periods. It further showed that amounts and uncertainties in (i) total NER, (ii) NER formed from the parent pool, and (iii) NER formed from the metabolite pool vary considerably among data sets at t→∞, with no clear dominance between (ii) and (iii). However, compounds containing aromatic amine moieties were found to form significantly more total NER when extrapolating to t→∞ than the other compounds studied. Overall, our study stresses the general need for assessing uncertainties, identifiability issues, and resulting biases when using inverse modeling of degradation time series for evaluating persistence and NER formation.
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Affiliation(s)
- Martin Loos
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
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73
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Lapworth DJ, Baran N, Stuart ME, Ward RS. Emerging organic contaminants in groundwater: A review of sources, fate and occurrence. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2012; 163:287-303. [PMID: 22306910 DOI: 10.1016/j.envpol.2011.12.034] [Citation(s) in RCA: 790] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 11/21/2011] [Accepted: 12/15/2011] [Indexed: 05/19/2023]
Abstract
Emerging organic contaminants (EOCs) detected in groundwater may have adverse effects on human health and aquatic ecosystems. This paper reviews the existing occurrence data in groundwater for a range of EOCs including pharmaceutical, personal care, 'life-style' and selected industrial compounds. The main sources and pathways for organic EOCs in groundwater are reviewed, with occurrence data for EOCs in groundwater included from both targeted studies and broad reconnaissance surveys. Nanogram-microgram per litre concentrations are present in groundwater for a large range of EOCs as well as metabolites and transformation products and under certain conditions may pose a threat to freshwater bodies for decades due to relatively long groundwater residence times. In the coming decades, more of these EOCs are likely to have drinking water standards, environmental quality standards and/or groundwater threshold values defined, and therefore a better understanding of the spatial and temporal variation remains a priority.
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Affiliation(s)
- D J Lapworth
- British Geological Survey, Mclean Building, Wallingford, Oxfordshire OX10 8BB, UK.
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74
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Fang G, Si Y, Tian C, Zhang G, Zhou D. Degradation of 2,4-D in soils by Fe₃O₄ nanoparticles combined with stimulating indigenous microbes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2012; 19:784-793. [PMID: 21948126 DOI: 10.1007/s11356-011-0597-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 08/25/2011] [Indexed: 05/31/2023]
Abstract
PURPOSE Degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) in soils by Fe₃O₄ nanoparticles combined with soil indigenous microbes was investigated, and the effects of Fe₃O₄ nanoparticles on soil microbial populations and enzyme activities were also studied. METHODS The soils contaminated with 2,4-D were treated with Fe₃O₄ nanoparticles. The microbial populations and enzyme activities were analyzed by dilution plate method and chemical assay, respectively, and the concentration of 2,4-D in soil was determined by high-performance liquid chromatography (HPLC). RESULTS The results indicated that Fe₃O₄ nanoparticles combined with soil indigenous microbes led to a higher degradation efficiency of 2,4-D than the treatments with Fe₃O₄ nanoparticles or indigenous microbes alone. The degradation of 2,4-D in soils followed the pseudo first-order kinetic. The half-lives of 2,4-D degradation (DT₅₀) of the combined treatments were 0.9, 1.9 and 3.1 days in a Red soil, Vertisol and Alfisol, respectively, which implied that the DT₅₀ of the combination treatments were significantly shorter than that of the treatments Fe₃O₄ nanoparticles or indigenous microbes alone. The effects of Fe₃O₄ nanoparticles on soil microbial populations and enzyme activities were also investigated and compared with the α-Fe₂O₃ nanoparticles. The results suggested that the α-Fe₂O₃ nanoparticles had only comparatively small effects on degradation of 2,4-D in soils, while the Fe₃O₄ nanoparticles not only degraded 2,4-D in soils but also increased the soil microbial populations and enzyme activities; the maximum increase in enzyme activities were 67.8% (amylase), 53.8% (acid phosphatase), 26.5% (catalase) and 38.0% (urease), compared with the untreated soil. Moreover, the introduction of Fe₃O₄ nanoparticles at the different dosage resulted in a variable degradation efficiency of 2,4-D in soil. CONCLUSION The method of combining Fe₃O₄ nanoparticles with indigenous soil microbes may offer great benefits for the application of nanotechnology in remediation of herbicide contaminated soil.
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Affiliation(s)
- Guodong Fang
- School of Resources and Environment, Anhui Agricultural University, Hefei 230036, China
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75
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Wilson LD, Mohamed MH, Berhaut CL. Sorption of Aromatic Compounds with Copolymer Sorbent Materials Containing β-Cyclodextrin. MATERIALS 2011; 4:1528-1542. [PMID: 28824156 PMCID: PMC5448859 DOI: 10.3390/ma4091528] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 08/05/2011] [Accepted: 08/17/2011] [Indexed: 11/23/2022]
Abstract
Urethane copolymer sorbent materials that incorporate β-cyclodextrin (CD) have been prepared and their sorption properties with chlorinated aromatic compounds (i.e., pentachlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxy acetic acid) have been evaluated. The sorption properties of granular activated carbon (GAC) were similarly compared in aqueous solution at variable pH conditions. The sorbents displayed variable BET surface areas as follows: MDI-X copolymers (< 101 m2/g), CDI-X copolymers (< 101 m2/g), and granular activated carbon (GAC ~103 m2/g). The sorption capacities for the copolymers sorbents are listed in descending order, as follows: GAC > CDI-3 copolymer ≈ MDI-3 copolymer. The sorption capacity for the aromatic adsorbates with each sorbent are listed in descending order, as follows: 2,4-dichlorophenol > 2,4-dichlorophenoxy acetic acid > pentachlorophenol. In general, the differences in the sorption properties of the copolymer sorbents with the chlorinated organics were related to the following factors: (i) surface area of the sorbent; (ii) CD content and accessibility; and (iii) and the chemical nature of the sorbent material.
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Affiliation(s)
- Lee D Wilson
- Department of Chemistry, 110 Science Place (Rm. 156), University of Saskatchewan, Saskatoon, SK S7N 5C9, Canada.
| | - Mohamed H Mohamed
- Aquatic Ecosystems Protection Research Division, Water Science and Technology Directorate, 11 Innovation Boulevard, Saskatoon, SK S7N 3H5, Canada.
| | - Christopher L Berhaut
- École Nationale Superieure de Chimie de Montpellier, 8 Rue de l'Ecole Normale, Montpellier 34296 CEDEX 5, France.
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