Soil Sorption of Acidic Pesticides

Spadotto, C. A.; Hornsby, Arthur G.

doi:10.2134/jeq2003.9490

Cited by 48 publications

(24 citation statements)

References 30 publications

(43 reference statements)

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“…This presumably results from the fact that SCP Ϫ is more water soluble than the neutral SCP species (SCP 0 ) and the electrostatic repulsion of SCP Ϫ from increasingly negatively charged soil surfaces. Similar pH effects have been observed for various organic acids sorbing to soils and sediments [11,13,16,21,29].…”

Section: Influence Of Phsupporting

confidence: 75%

“…This can be explained by the relatively complex structures of these compounds, which often contain more than one functional group and frequently are ionizable. The pH and ionic strength have been demonstrated to affect the sorption of ionizable chemicals to soil and sediment [11][12][13][14][15][16], octanol [17], membranes [18], and proteins [19]. Changing the pH leads to protonation or deprotonation of ionizable compounds, thereby changing the physicochemical properties and, subsequently, the sorption of a compound.…”

Section: Introductionmentioning

confidence: 99%

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The effect of pH and ionic strength on the sorption of sulfachloropyridazine, tylosin, and oxytetracycline to soil

Laak

Gebbink

Tolls

2006

Enviro Toxic and Chemistry

213

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Antimicrobial agents are the most heavily used pharmaceuticals in intensive husbandry. Their usual discharge pathway is application to agricultural land as constituents of animal manure, which is used as fertilizer. Many of these compounds undergo pH-dependent speciation and, therefore, might occur as charged species in the soil environment. Hence, pH and ionic strength of the soil suspension can affect the sorption behavior of these compounds to soil. Consequently, the soil sorption of three antimicrobial agents--sulfachloropyridazine (SCP), tylosin (TYL), and oxytetracycline (OTC)--was investigated. Their respective sorption coefficients in two agricultural soils ranged from 1.5 to 1,800 L/kg. Sorption coefficients were greater under acidic conditions. Addition of an electrolyte to the solution led to decreased sorption of TYL and OTC by a factor of 3 to 20, but it did not influence the sorption of SCP. This behavior was analyzed by accounting for the pH-dependent speciation of TYL and OTC and considering the presence of OTC-calcium complexes. It appears that the decreased sorption of TYL and OTC with increasing ionic strength results from competition of the electrolyte cations with the positively charged TYL species and the positively charged OTC complexes. A model linking sorbate speciation with species-specific sorption coefficients can describe the pH dependence of the apparent sorption coefficients. This modeling approach is proposed for implementation in the assessment of sorption of ionizable compounds.

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Section: Influence Of Phsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

The effect of pH and ionic strength on the sorption of sulfachloropyridazine, tylosin, and oxytetracycline to soil

Laak

Gebbink

Tolls

2006

Enviro Toxic and Chemistry

213

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“…A review of studies on modeling of the pH-dependent adsorption of organic acids that were carried out for more than 25 yr by many authors was not the aim of the present study. Details concerning this subject can be found elsewhere [28,44,50,[88][89][90]. This topic merits a brief discussion, however, because the finding that adsorption of 2,4-D, MCPA, dichlorprop, and mecoprop in soils is significantly inversely correlated with their log D values may have significant effects on advances in the prediction of adsorption of these compounds in soils.…”

Section: Aspects Of Modeling the Adsorption Of 24-d Mcpa Dichlorprmentioning

confidence: 99%

“…The increase in the Ca 2þ concentration causes a slight increase in the adsorption of anions of phenoxyalkanoic acid herbicides on organic matter, kaolinite, and quartz through a Ca-bridging mechanism [50,75]. Despite this, an increase of pH in the plough layer of arable soil, which is the result of liming [167], decreases the adsorption of phenoxyalkanoic acid herbicides [20,38,88] because the affinity of organic matter for the anionic form is at least 10 times less than that for the neutral forms of these compounds [27,44,50]. A study by McGhee and Burns [109] indicated that liming slightly inhibited the degradation rate of 2,4-D and MCPA in soils.…”

Section: Influence Of Liming and Fertilizers On Leachingmentioning

confidence: 99%

Adsorption and degradation of phenoxyalkanoic acid herbicides in soils: A review

Paszko

Muszyński

Materska

et al. 2016

Enviro Toxic and Chemistry

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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. Environ Toxicol Chem 2016;35:271-286. # 2015 SETAC

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“…A large number of experimental investigations has addressed the sorption and/or desorption of phenoxyalkanoic acid herbicides in soils, and on individual soil components or various inorganic sorbents (see Hermosin & Cornejo, 1993;Benoit et al, 1996;Haberhauer et al, 2000;Spadotto & Hornsby, 2003). It was observed that some electrolytes in solutions have an important impact on the sorption behaviour of phenoxyacetic acids on clay minerals.…”

Section: Introductionmentioning

confidence: 99%

Formation of 2,4–D complexes on montmorillonites – an ab initio molecular dynamics study

Tunega

Gerzabek

Haberhauer

et al. 2006

European J Soil Science

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Sorption of the anionic form of the pesticide 2,4-D (2,4-dichlorophenoxyacetic acid) on the surface of the clay mineral montmorillonite was investigated using a short-time ab initio molecular dynamics (MD) simulation at room temperature. Three different situations were modelled: sorption on a dry surface, on a hydrated surface and an intercalation between montmorillonite layers. In all three cases, the calcium cation compensates the excess negative charge of the montmorillonite layer and the negative charge of the 2,4-D anion. It was found that in all models with direct contact of the Ca 2þ cation with the montmorillonite layer, the most stable position of Ca 2þ is above the ditrigonal hole of the mineral layer. While in the case of a dry surface very stable bidentate binding is created between the 2,4-D anion and the Ca 2þ cation, the formation of the monodentate complexes is preferred in all models that include water molecules. Hydrogen bonds formed between water molecules and the 2,4-D anion make a considerable contribution to the formation of the monodentate complexes. Tetrahedral substitutions in the montmorillonite layer have a significant effect on the formation of the complexes of any type. However, the MD simulations did not support the role of Ca 2þ as a cation bridge in the adsorption mechanism. Calculations showed that hydrated 2,4-DÁÁÁCa 2þ complexes are thermodynamically more stable than complexes in which the Ca 2þ cation acts as a bridge to the surface. On the other hand, it is possible that phyllosilicates with a greater concentration of isomorphic substitutions (e.g. mica) will be able to form stable surface complexes with a cation bridge mechanism.

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Soil Sorption of Acidic Pesticides

Cited by 48 publications

References 30 publications

The effect of pH and ionic strength on the sorption of sulfachloropyridazine, tylosin, and oxytetracycline to soil

The effect of pH and ionic strength on the sorption of sulfachloropyridazine, tylosin, and oxytetracycline to soil

Adsorption and degradation of phenoxyalkanoic acid herbicides in soils: A review

Formation of 2,4–D complexes on montmorillonites – an ab initio molecular dynamics study

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