Interaction of Btpyridylium Herbicides With Organo‐clay Complex

Khan, Shahamat U.

doi:10.1111/j.1365-2389.1973.tb00761.x

Cited by 23 publications

(6 citation statements)

References 11 publications

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“…We determined the simple correlations between the Kf and Downloaded by [York University Libraries] at 18:27 19 November 2014 Kd OM-ODTMA /Kfd OM ratio, suggest that this pesticide is adsorbed by clay-humus complexes formed in the soil. Different authors have reported that when these complexes are present in soils containing montmorillonite, they enhance the sorbent power of the clay and that of the OM (Khan, 1973;Sánchez-Camazano and Sánchez-Martín, 1990).…”

Section: Resultsmentioning

confidence: 98%

Comparison of Pesticide Sorption by Physicochemically Modified Soils with Natural Soils as a Function of Soil Properties and Pesticide Hydrophobicity

Rodríguez‐Cruz

Sánchez-Martín

Andrades

et al. 2006

Soil and Sediment Contamination: An International Journal

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The objectives of this paper were to determine the efficiency of physicochemically modified soils with a surfactant in the sorption of pesticides, the stability against washing of the pesticides sorbed, and the effective sorption capacity of surfactant adsorbed by soils as a function of pesticide hydrophobicity and soil characteristics. Five soils of different characteristics and five pesticides (penconazole, linuron, alachlor, atrazine and metalaxyl) with different Kow values were selected and octadecyltrimethylammonium bromide (ODTMA) was chosen as model of cationic surfactants. Sorption-desorption isotherms were obtained and constants Kf and Kfd for natural soils (from Freundlich equation) and K and Kd for ODTMA-soils (from linear equation) were determined. Sorption on ODTMA-soils was higher than on natural soils. K increased 27-165 times for penconazole, 22-77 times for linuron, 7-14 times for alachlor, 9-23 times for atrazine, and 21-333 times for metalaxyl in relation to Kf. Sorption coefficients normalized to 100% of total organic matter (TOM) from organo soils K OM (K 100/%TOM), were always higher than those from natural soils Kf OM (Kf 100/%OM), indicating that the organic matter (OM) derived from the ODTMA (OM ODTMA ) had a greater sorption capacity than the OM of the natural soil. K OM values were also higher than the Kow (octanol/water distribution coefficient) value for each pesticide. The similarity of the high K OM values for the sorption of each pesticide by the five soils and the linearity of isotherms point to a partitioning of the pesticides between surfactant and water. The use in this work of different soils and various pesticides, unusual in this type of investigation, allowed us to obtain equations to know the sorbed amount of a given pesticide by the surfactant-modified soils as a function of the OM content derived from the cation and the Kow of the pesticide. The results obtained are of interest when it becomes necessary to increase the sorption capacity of soils with low OM contents with a view to delaying pesticide mobility in soils from pollution point sources (high concentration in small area), and preventing the pollution of waters.

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Section: Resultsmentioning

confidence: 98%

Comparison of Pesticide Sorption by Physicochemically Modified Soils with Natural Soils as a Function of Soil Properties and Pesticide Hydrophobicity

Rodríguez‐Cruz

Sánchez-Martín

Andrades

et al. 2006

Soil and Sediment Contamination: An International Journal

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“…Reduced mobility and biocidal activity due to bonding to humic substances are often described (5)(6)(7)(8). It is in some cases supported by various experimental results, that parent molecules or metabolites are bound to the humic matrix either by covalent bonding (9)(10)(11)(12)(13)(14)(15)(16)51), ionic bonding (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28), charge transfer complexes (29)(30)(31)(32)(33), ligand exchange (34,35), hydrogen bonding (23,31,(36)(37)(38)(39)(40), van der Waals forces (22,(41)(42)(43)(44), hydrophobic sorption (45)(46)(47)(48)(49)…”

Section: Comission On Pesticide Chemistrymentioning

confidence: 88%

Soil-Bound Residues

Burauel

Wais

Führ

1998

ACS Symposium Series

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“…Such an association may facilitate adsorption of pesticides by inorganic constituents (Khan, 1973). Therefore, it is the combined inorganic-organic colloid interaction that needs to be evaluated in determining the full magnitude of pesticide adsorption capacity by colloids (Saltzman et al, 1972).…”

Section: Introductionmentioning

confidence: 99%

Colloid-facilitated transport of metolachlor through intact soil columns

Seta¹,

Karathanasis²

1996

J. of Env. Sc. & Hlth., Part B

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This study evaluated the role of water dispersible colloids with diverse physicochemical and mineralogical characteristics in facilitating the transport of metolachlor through macropores of intact soil columns. The soil columns represented upper solum horizons of an Alfisol in the Bluegrass region of Kentucky. Three different colloid suspensions tagged with metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-l-methylethyl)acetamide] were introduced at a constant flux into undisturbed soil columns. The eluents were 949 950 SETA AND KARATHANASIS collected and analyzed periodically for colloid and metolachlor concentrations. Colloid recovery in the eluents ranged from 54 to 90 %. The presence of colloids enhanced the transport of metolachlor by 22 to 70 % depending on the colloid type and mobility. Colloids with higher pH, organic carbon, cation exchange capacity (CEC), total exchangeable bases (TEB), surface area (SA), and electrophoretic mobility (EM), showed better mobility, greater affinity for interaction with the herbicide and, thus, greater potential to co-transport metolachlor. In contrast, increased level of kaolinite, Fe, and Al inhibited metolachlor adsorption and transport. In spite of the increased transportability of metolachlor by the presence of soil colloids, the colloid bound herbicide portion accounted for a very small part of the observed increase. This suggests that surface site exclusion mechanisms and preferential sorption induced by the presence of colloids are more important than ion exchange phenomena in promoting herbicide mobility in subsurface environments.

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Interaction of Btpyridylium Herbicides With Organo‐clay Complex

Cited by 23 publications

References 11 publications

Comparison of Pesticide Sorption by Physicochemically Modified Soils with Natural Soils as a Function of Soil Properties and Pesticide Hydrophobicity

Comparison of Pesticide Sorption by Physicochemically Modified Soils with Natural Soils as a Function of Soil Properties and Pesticide Hydrophobicity

Soil-Bound Residues

Colloid-facilitated transport of metolachlor through intact soil columns

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