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Blachnio M, Kusmierek K, Swiatkowski A, Derylo-Marczewska A. Adsorption of Phenoxyacetic Herbicides from Water on Carbonaceous and Non-Carbonaceous Adsorbents. Molecules 2023; 28:5404. [PMID: 37513275 PMCID: PMC10385827 DOI: 10.3390/molecules28145404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/07/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
The increasing consumption of phenoxyacetic acid-derived herbicides is becoming a major public health and environmental concern, posing a serious challenge to existing conventional water treatment systems. Among the various physicochemical and biological purification processes, adsorption is considered one of the most efficient and popular techniques due to its high removal efficiency, ease of operation, and cost effectiveness. This review article provides extensive literature information on the adsorption of phenoxyacetic herbicides by various adsorbents. The purpose of this article is to organize the scattered information on the currently used adsorbents for herbicide removal from the water, such as activated carbons, carbon and silica adsorbents, metal oxides, and numerous natural and industrial waste materials known as low-cost adsorbents. The adsorption capacity of these adsorbents was compared for the two most popular phenoxyacetic herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA). The application of various kinetic models and adsorption isotherms in describing the removal of these herbicides by the adsorbents was also presented and discussed. At the beginning of this review paper, the most important information on phenoxyacetic herbicides has been collected, including their classification, physicochemical properties, and occurrence in the environment.
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Affiliation(s)
- Magdalena Blachnio
- Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Krzysztof Kusmierek
- Institute of Chemistry, Military University of Technology, Gen. S. Kaliskiego St. 2, 00-908 Warszawa, Poland
| | - Andrzej Swiatkowski
- Institute of Chemistry, Military University of Technology, Gen. S. Kaliskiego St. 2, 00-908 Warszawa, Poland
| | - Anna Derylo-Marczewska
- Faculty of Chemistry, Maria Curie-Sklodowska University, M. Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
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Mierzejewska E, Tołoczko W, Urbaniak M. The effects of syringic acid on the properties of MCPA-contaminated soil and the growth of two cucurbit species. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2021; 24:205-214. [PMID: 34126809 DOI: 10.1080/15226514.2021.1932727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The aim of this study was to determine the influence of syringic acid (SA), a plant secondary metabolite (PSM), on the properties of soil contaminated with 2-methyl-4-chlorophenoxyacetic acid (MCPA) and the condition of two cucurbit species zucchini (C. pepo L. 'Atena Polka') and cucumber (C. sativus 'Cezar') grown on that soil. It was found that amendment with MCPA and MCPA + SA modified the soil physico-chemical properties. Content of N and K was significantly higher for variants amended with SA and/or MCPA, while P content was lower in variant amended with SA. The cucurbits demonstrated varied efficiencies in mitigating the phytotoxicity of the MCPA-treated soil. For soil amended with MCPA + SA, samples remediated with cucumber were characterized as slightly toxic or toxic (45.2%-81.5%), while those planted with zucchini were nontoxic or slightly toxic (-40.6%-47.8%). Development of cucumber seedlings was fully inhibited by MCPA, regardless of SA application, zucchini demonstrated enhanced growth in soil treated with MCPA + SA and no statistically significant differences between morphological parameters of MCPA + SA-treated zucchini in comparison to control plants were observed. The obtained findings suggest that the application of SA is a promising way to mitigate the toxic influence of MCPA in the soil, depending on the cultivated plant species. Novelty statement: The study meets the criteria of novelty and innovativeness. Most importantly, the study is focused on: phytotoxicity studies to inform about the limitations of phytotechnology based on PSMs. Additionally, this manuscript provides an interdisciplinary description of the effects of MCPA and naturally occurring PSM- SA on cucurbits and soil parameters. Such studies, which combine the interactions between cucurbits, their secondary metabolite (SA) and their role in mitigation of phytotoxicity in MCPA-contaminated soil, has not been performed before.
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Affiliation(s)
- Elżbieta Mierzejewska
- UNESCO Chair on Ecohydrology and Applied Ecology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
| | - Wojciech Tołoczko
- Department of Physical Geography, Faculty of Geography, University of Lodz, Lodz, Poland
| | - Magdalena Urbaniak
- UNESCO Chair on Ecohydrology and Applied Ecology, Faculty of Biology and Environmental Protection, University of Lodz, Lodz, Poland
- European Regional Centre for Ecohydrology of the Polish Academy of Sciences, Lodz, Poland
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology in Prague, Prague, Czech Republic
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Wu D, Yun Y, Jiang L, Wu C. Influence of dissolved organic matter on sorption and desorption of MCPA in ferralsol. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 616-617:1449-1456. [PMID: 29070453 DOI: 10.1016/j.scitotenv.2017.10.169] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 10/16/2017] [Accepted: 10/16/2017] [Indexed: 05/09/2023]
Abstract
MCPA (4-chloro-2-methylphenoxyacetic acid) is an acidic herbicide, widely used in paddy fields. The presence of dissolved organic matter (DOM) modifies the sorption-desorption of herbicides in soils. In this study, effects of DOM on sorption- desorption of MCPA were tested using three typical ferralsol soil types from China: rhodic ferralsol, haplic ferralsol and paddy soil. DOM preparations were extracted from the paddy soil (DOMP), from a compost mixture of cassava stems with chicken manure (DOMC), and from rice straw (DOMR). Sorption-desorption of MCPA in the tested soil types was shown to follow pseudo first-order kinetics, and the calculated isotherm data fitted well with a Freundlich equilibrium model in the range of the studied concentrations. MCPA was weakly sorbed by the soils, producing low Freundlich coefficient values (Kf) (0.854 to 4.237). The presence of DOM reduced the Kf whereby DOMC had the strongest and DOMR the weakest effect. Presence of DOM also promoted MCPA desorption from the soils, again with DOMC having the strongest effect and DOMR the weakest. DOM coating changed the soil particle surface, as demonstrated by electron microscopy, and DOM also directly interacted with MCPA, as shown by Fourier-transform infrared spectroscopy. The experimental data were interpreted to suggest a competing sorption of DOM to ferralsol and an increased solubility of MCPA in the presence of DOM. The results indicate that the environmental risk of MCPA leaching to groundwater and surface flow is increased by presence of DOM, for instance as a result of organic fertilizer use.
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Affiliation(s)
- Dongming Wu
- Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, PR China
| | - Yonghuan Yun
- Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, PR China
| | - Lei Jiang
- Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, PR China; Danzhou Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture, Danzhou 571737, PR China
| | - Chunyuan Wu
- Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, PR China; Danzhou Scientific Observing and Experimental Station of Agro-Environment, Ministry of Agriculture, Danzhou 571737, PR China.
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Paradelo R, Conde-Cid M, Martin Abad E, Nóvoa-Muñoz JC, Fernández-Calviño D, Arias-Estévez M. Retention and transport of mecoprop on acid sandy-loam soils. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 148:82-88. [PMID: 29031878 DOI: 10.1016/j.ecoenv.2017.10.007] [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: 05/19/2017] [Revised: 09/27/2017] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Abstract
Interaction with soil components is one of the key processes governing the fate of agrochemicals in the environment. In this work, we studied the adsorption / desorption and transport of mecoprop (methylchlorophenoxypropionic acid or MCPP) in four acid sandy-loam soils with different organic matter contents. Kinetics of adsorption and adsorption/desorption at equilibrium were studied in batch experiments, whereas transport was studied in laboratory columns. Adsorption and desorption were found to be linear or nearly-linear. The kinetics of mecoprop adsorption were relatively fast in all cases (less than 24h). Adsorption and desorption were adequately described by the linear and Freundlich models, with KF values that ranged from 0.7 to 8.8Ln µmol1-nkg-1 and KD values from 0.3 to 3.6Lkg-1. The results of the transport experiments showed that the retention of mecoprop by soil was very low (less than 6.2%). The retention of mecoprop by the soils in all experiments increased with organic matter content. Overall, it was observed that mecoprop was weakly adsorbed by the soils, what would result in a high risk of leaching of this compound in the environment.
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Affiliation(s)
- R Paradelo
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Universidade de Vigo, Spain.
| | - M Conde-Cid
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Universidade de Vigo, Spain
| | - E Martin Abad
- Institut des Sciences et Industries du Vivant et de l'Environnement (AgroParisTech), 16 rue Claude-Bernard, 75005 Paris, France
| | - J C Nóvoa-Muñoz
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Universidade de Vigo, Spain
| | - D Fernández-Calviño
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Universidade de Vigo, Spain
| | - M Arias-Estévez
- Área de Edafoloxía e Química Agrícola, Departamento de Bioloxía Vexetal e Ciencia do Solo, Universidade de Vigo, Spain
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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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Santiago CC, Fernández MA, Torres Sánchez RM. Adsorption and characterization of MCPA on DDTMA- and raw-montmorillonite: Surface sites involved. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2016; 51:245-253. [PMID: 26786275 DOI: 10.1080/03601234.2015.1120618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The 4-chloro-2-methylphenoxy acid (MCPA) is an herbicide widely used in agriculture, which generates a great concern about contamination of surface water and serious consequences for human health and the environment. In this work, the adsorption of MCPA on an Argentine montmorillonite (MMT) and its organo-montmorillonite product (OMMT) with different dodecyl trimethyl ammonium loading was investigated. MCPA adsorption on OMMT increases at least 3 times, with respect to the amount determined for MMT. X-ray diffraction and zeta potential analyses indicated the inner (interlayer) and outer surface participate as adsorption sites. Changes in surface electric charge and also interlayer expansion suggest that dimethyl amine (MCPA counterion) was also surface-adsorbed. The larger aggregates of OMMT, without and with MCPA, obtained compared to those of MMT samples, generate an improvement in the coagulation efficiency. This property, particularly after MCPA retention, allows an easier separation of the solids from the solution and enables a simple technological process application.
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Affiliation(s)
- Cintia C Santiago
- a Technology Center of Mineral Resources and Ceramics , M. B. Gonnet , Argentina
| | - Mariela A Fernández
- a Technology Center of Mineral Resources and Ceramics , M. B. Gonnet , Argentina
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Paszko T. Modeling of pH-dependent adsorption and leaching of MCPA in profiles of Polish mineral soils. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 494-495:229-240. [PMID: 25051325 DOI: 10.1016/j.scitotenv.2014.06.129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2014] [Revised: 06/28/2014] [Accepted: 06/28/2014] [Indexed: 06/03/2023]
Abstract
This study aimed to determine the leaching potential of MCPA and the contribution of major soil components to its retention in 27 profiles of common Polish arable soils. Results of experiments and modeling of the pH-dependent adsorption indicated that the adsorption of the neutral and anionic forms of MCPA on soil organic matter are the predominant adsorption mechanisms, even in soil horizons with very low organic matter contents. The third most important mechanism was the adsorption of MCPA anions, most likely through the water bridging mechanism on sorption sites created by exchangeable Fe cations adsorbed in soil. It was found that in acidic soils with very low organic matter contents, the neutral form of MCPA was also adsorbed on the quartz and silica sorption sites of silt and sand. The value of r(2) was 78% when it was assumed that MCPA was adsorbed only on organic matter and 93% when all indicated mechanisms of adsorption on mineral soil components were included in the model fitted to data from all soil profiles. Simulations using FOCUS PELMO indicated that in two profiles, the 80th percentiles of the average yearly concentrations of MCPA in the leachate exceeded the European Union (EU) contamination limit of 0.1 μgL(-1). It was shown that when an assumption was made in the model of pH-dependent adsorption that MCPA was adsorbed only on organic matter, the leaching potential of MCPA was overestimated in the examined soils. Much better predictions were obtained when adsorption on mineral soil components was also included in the model.
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Affiliation(s)
- Tadeusz Paszko
- Department of Chemistry, University of Life Sciences, Akademicka 13, 20-950 Lublin, Poland.
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Piwowarczyk AA, Holden NM. Phenoxyalkanoic acid herbicide sorption and the effect of co-application in a Haplic Cambisol with contrasting management. CHEMOSPHERE 2013; 90:535-541. [PMID: 22959720 DOI: 10.1016/j.chemosphere.2012.08.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/25/2012] [Accepted: 08/07/2012] [Indexed: 06/01/2023]
Abstract
The adsorption and desorption behaviour of two phenoxyalkanoic acid herbicides (MCPA and mecoprop-p) in a Haplic Cambisol with tillage and grassland management was examined using a batch equilibrium method. Additionally, the effect on adsorption of the simultaneous presence of the two herbicides was also studied. The sorption equilibrium was reached within 24h for adsorption and desorption in both soils. The experimental sorption data for MCPA and mecoprop-p fitted the Freundlich and the linear adsorption isotherms very well (R(2)>0.99). The Freundlich exponent values of the adsorption isotherm ranged from 0.91 to 0.98 indicating a non-linear and a linear adsorption of the two chemicals studied. Generally, mecoprop-p showed lower adsorption than MCPA, although the adsorption of both phenoxyalkanoic acid herbicides was low. The adsorption process was not fully reversed during one washing cycle, as the K(f) values for desorption were greater than corresponding K(f) values for adsorption. The Freundlich exponent (1/n) of the MCPA adsorption isotherm was affected by the simultaneous presence of both herbicides and tended more towards non-linearity, whilst the mecoprop-p adsorption exponent remained unaltered. The Freundlich and the linear adsorption coefficients calculated in the mix study were not that different from the adsorption coefficients calculated in the single compound study, and therefore single compound adsorption data can be used when modelling the fate of simultaneously applied phenoxyalkanoic acid herbicides. The study also indicated that both herbicides were poorly sorbed by the soils studied, and therefore may pose a risk of surface and/or groundwater pollution in Ireland.
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Affiliation(s)
- Agnieszka A Piwowarczyk
- UCD School of Biosystems Engineering, University College Dublin, Belfield, Dublin 4, Ireland.
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Waldner G, Friesl-Hanl W, Haberhauer G, Gerzabek MH. Differences in sorption behavior of the herbicide 4-chloro-2-methylphenoxyacetic acid on artificial soils as a function of soil pre-aging. JOURNAL OF SOILS AND SEDIMENTS 2012; 12:1292-1298. [PMID: 26074728 PMCID: PMC4461184 DOI: 10.1007/s11368-012-0550-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 06/08/2012] [Indexed: 06/03/2023]
Abstract
PURPOSE The sorption behavior of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) to three different artificial soil mixtures was investigated. Artificial soils serve as model systems for improving understanding of sorption phenomena. MATERIALS AND METHODS The soils consisted of quartz, ferrihydrite, illite, montmorillonite, and charcoal. In a previous study, several selected mixtures had been inoculated with organic matter, and microbial aging (incubation) had been performed for different periods of time (3, 12, and 18 months) before conducting the sorption experiments. The effect of this pre-incubation time on the sorption behavior was determined. Interaction of MCPA with soil surfaces was monitored by aqueous phase sorption experiments, using high-performance liquid chromatography/ultraviolet and in selected cases Fourier-transformed infrared spectroscopy. RESULTS AND DISCUSSION The sorption behavior showed large differences between differently aged soils; Freundlich and linear sorption model fits (with sorption constants Kf , 1/n exponents, and Kd values, respectively) were given for pH = 3 and the unbuffered pH of ∼7. The largest extent of sorption from diluted solutions was found on the surfaces with a pre-incubation time of 3 months. Sorption increased at acidic pH values. CONCLUSIONS Regarding the influence of aging of artificial soils, the following conclusions were drawn: young artificial soils exhibit stronger sorption at lower concentrations, with a larger Kf value than aged soils. A correlation with organic carbon content was not confirmed. Thus, the sorption characteristics of the soils are more influenced by the aging of the organic carbon than by the organic carbon content itself.
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Affiliation(s)
- Georg Waldner
- Health and Environment Department, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria
| | - Wolfgang Friesl-Hanl
- Health and Environment Department, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Strasse 24, 3430 Tulln, Austria
| | - Georg Haberhauer
- Institute of Soil Research, University of Natural Resources and Life Sciences, Peter-Jordan-Strasse 82, 1190 Vienna, Austria
| | - Martin H. Gerzabek
- Institute of Soil Research, University of Natural Resources and Life Sciences, Peter-Jordan-Strasse 82, 1190 Vienna, Austria
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Hiller E, Tatarková V, Šimonovičová A, Bartal' M. Sorption, desorption, and degradation of (4-chloro-2-methylphenoxy)acetic acid in representative soils of the Danubian Lowland, Slovakia. CHEMOSPHERE 2012; 87:437-444. [PMID: 22206646 DOI: 10.1016/j.chemosphere.2011.12.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 12/07/2011] [Accepted: 12/08/2011] [Indexed: 05/31/2023]
Abstract
Herbicide leaching through soil into groundwater greatly depends upon sorption-desorption and degradation phenomena. Batch adsorption, desorption and degradation experiments were performed with acidic herbicide MCPA and three soil types collected from their respective soil horizons. MCPA was found to be weakly sorbed by the soils with Freundlich coefficient values ranging from 0.37 to 1.03 mg(1-1/)(n) kg(-1) L(1/)(n). It was shown that MCPA sorption positively correlated with soil organic carbon content, humic and fulvic acid carbon contents, and negatively with soil pH. The importance of soil organic matter in MCPA sorption by soils was also confirmed by performing sorption experiments after soil organic matter removal. MCPA sorption in these treated soils decreased by 37-100% compared to the original soils. A relatively large part of the sorbed MCPA was released from soils into aqueous solution after four successive desorption steps, although some hysteresis occurred during desorption of MCPA from all soils. Both sorption and desorption were depth-dependent, the A soil horizons exhibited higher retention capacity of the herbicide than B or C soil horizons. Generally, MCPA sorption decreased in the presence of phosphate and low molecular weight organic acids. Degradation of MCPA was faster in the A soil horizons than the corresponding B or C soil horizons with half-life values ranging from 4.9 to 9.6 d in topsoils and from 11.6 to 23.4 d in subsoils.
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Affiliation(s)
- Edgar Hiller
- Department of Geochemistry, Comenius University in Bratislava, Mlynska dolina, 842 15 Bratislava, Slovakia.
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