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M. Hartig - One of the best experts on this subject based on the ideXlab platform.

  • Zur ixodiziden Wirksamkeit von Clenpyrin, Chlordimeform und Chlormethiuron gegen PE‐resistente Boophilus microplus‐Stämme
    Zentralblatt fur Veterinarmedizin. Reihe B. Journal of veterinary medicine. Series B, 2010
    Co-Authors: R. Gothe, M. Hartig
    Abstract:

    Zusammenfassung Durch in vitro Untersuchungen mit weiblichen Zecken der PE-resistenten Stamme Biarra, Mackay und Mt. Alford sowie dem sensitiven Standard Yeerongpilly wurden die Reaktionslagen fur die Cholinesterase nicht hemmenden Akarizide Clenpyrin, Chlordimeform und Chlormethiuron durch Festlegung der Quotienten aus Konzentrationen, die die Vermehrungskapazitat der PE-resistenten Stamme und des Bezugsstandards Yeerongpilly um 50% einschrankt, in verschiedenen Expositionsbereichen quantitativ bestinimt. Dabei konnte eindeutig nachgewiesen werden, das die PE-resistenten Stamme Biarra, Mackay und Mt. Alford bisher noch keine Resistenz gegenuber Clenpyrin, Chlordimeform und Chlormethiuron entwickelt haben. Eine zeitliche Verzogerung der Eiablage sowie der Embryonalentwicklung konnte bei allen Stammen nur unter der Einwirkung von Chlordimeform und Chlormethiuron festgestellt werden. Summary On the ixodicidal activity of Clenpyrin, Chlordimeform and Chlormethiuron against OP-resistant Boophilus microplus strains By in vitro investigations with female Boophilus microplus ticks of organophosphorus-resistant strains Biarra, Mackay and Mt. Alford as well as the sensitive strain Yeerongpilly, the degree of resistance against the cholinesterase non-blocking acaricides Clenpyrin, Chlordimeform and Chlormethiuron was quantitated by determination of the quotient from concentrations reducing the capacity of reproduction by 50% in different ranges of exposure. The results of the present experimental study show clearly that the organophosphorus resistant strains Biarra, Mackay and Mt. Alford had not developed any resistance against Clenpyrin, Chlordimeform and Chlormethiuron. A temporary retardation in oviposition as well as in embryonic developments in all strains could only be observed after treatment with Chlordimeform and Chlormethiuron. Resume A propos de l'action ixodicide de “Clenpyrin”, “Chlordimeform” et “Chlormethiuron” sur des souches de Boophilus microplus PE-resistantes On a determine in vitro et quantitativement dans differentes situations d'exposition les reactions a des acaricides non inhibiteurs de la cholinesterase (Clenpyrine, Chlordimeform et Chlormethiuran) chez des tiques femelles des souches resistantes Biana, Mackay, Mt. Alford et de la souche sensible Standard Yeerongpilly, en etablissant le quotient des concentrations qui limitaient a 50% la capacite de reproduction des souches PE-resistantes et du standard Yeerongpilly. On a pu demontrer de facon certaine que les souches PE-resistantes Biana, Mackay et Mt. Alford n'avaient developpe aucune resistance a Clenpyrine, Chlordimeform et Chlormethiuron. Seule l'action de Chlordimeform et Chlormethiuron provoqua un ralentissement temporaire de la ponte et du developpement embryonnaire. Resumen La potencia ixodicida de clenpirina, clordimeformo y clormetiuron frente a estirpes de Boophilus microplus resistentes a los esteres del acido fosforico (PE) Mediante estudios in vitro con garrapatas hembras de las estirpes resistentes a esteres del acido fosforico (PE) Biarra, Mackay y Mt. Alford, asi como con el estandar sensitivo Yeerongpilly, se valoraron cuantitativamente en varios ambitos de exposicion los grados de reaccion de los acaricidas, que no inhiben la colinesterasa, clenpirina, clordimeformo y clormetiuron, estable-ciendo los cocientes de concentraciones que reducen la capacidad de reproduccion de las estirpes resistentes a los PE y del estandar de referencia Yeerongpilly en un 50%. Asi se pudo probar, sin lugar a dudas, que las estirpes Biarra, Mackay y Mt. Alford, resistentes a los PE, no han desarrollado por ahora ninguna resistencia contra clenpirina, clordimeformo y clormetiuron. Se pudo comprobar en todas las estirpes una dilacion temporal en la oviposicion y en el desarrollo embrionario bajo la accion de clordimeformo y clormetiuron.

  • zur ixodiziden wirksamkeit von clenpyrin Chlordimeform und chlormethiuron gegen pe resistente boophilus microplus stamme
    Journal of Veterinary Medicine Series B-infectious Diseases and Veterinary Public Health, 2010
    Co-Authors: R. Gothe, M. Hartig
    Abstract:

    Zusammenfassung Durch in vitro Untersuchungen mit weiblichen Zecken der PE-resistenten Stamme Biarra, Mackay und Mt. Alford sowie dem sensitiven Standard Yeerongpilly wurden die Reaktionslagen fur die Cholinesterase nicht hemmenden Akarizide Clenpyrin, Chlordimeform und Chlormethiuron durch Festlegung der Quotienten aus Konzentrationen, die die Vermehrungskapazitat der PE-resistenten Stamme und des Bezugsstandards Yeerongpilly um 50% einschrankt, in verschiedenen Expositionsbereichen quantitativ bestinimt. Dabei konnte eindeutig nachgewiesen werden, das die PE-resistenten Stamme Biarra, Mackay und Mt. Alford bisher noch keine Resistenz gegenuber Clenpyrin, Chlordimeform und Chlormethiuron entwickelt haben. Eine zeitliche Verzogerung der Eiablage sowie der Embryonalentwicklung konnte bei allen Stammen nur unter der Einwirkung von Chlordimeform und Chlormethiuron festgestellt werden. Summary On the ixodicidal activity of Clenpyrin, Chlordimeform and Chlormethiuron against OP-resistant Boophilus microplus strains By in vitro investigations with female Boophilus microplus ticks of organophosphorus-resistant strains Biarra, Mackay and Mt. Alford as well as the sensitive strain Yeerongpilly, the degree of resistance against the cholinesterase non-blocking acaricides Clenpyrin, Chlordimeform and Chlormethiuron was quantitated by determination of the quotient from concentrations reducing the capacity of reproduction by 50% in different ranges of exposure. The results of the present experimental study show clearly that the organophosphorus resistant strains Biarra, Mackay and Mt. Alford had not developed any resistance against Clenpyrin, Chlordimeform and Chlormethiuron. A temporary retardation in oviposition as well as in embryonic developments in all strains could only be observed after treatment with Chlordimeform and Chlormethiuron. Resume A propos de l'action ixodicide de “Clenpyrin”, “Chlordimeform” et “Chlormethiuron” sur des souches de Boophilus microplus PE-resistantes On a determine in vitro et quantitativement dans differentes situations d'exposition les reactions a des acaricides non inhibiteurs de la cholinesterase (Clenpyrine, Chlordimeform et Chlormethiuran) chez des tiques femelles des souches resistantes Biana, Mackay, Mt. Alford et de la souche sensible Standard Yeerongpilly, en etablissant le quotient des concentrations qui limitaient a 50% la capacite de reproduction des souches PE-resistantes et du standard Yeerongpilly. On a pu demontrer de facon certaine que les souches PE-resistantes Biana, Mackay et Mt. Alford n'avaient developpe aucune resistance a Clenpyrine, Chlordimeform et Chlormethiuron. Seule l'action de Chlordimeform et Chlormethiuron provoqua un ralentissement temporaire de la ponte et du developpement embryonnaire. Resumen La potencia ixodicida de clenpirina, clordimeformo y clormetiuron frente a estirpes de Boophilus microplus resistentes a los esteres del acido fosforico (PE) Mediante estudios in vitro con garrapatas hembras de las estirpes resistentes a esteres del acido fosforico (PE) Biarra, Mackay y Mt. Alford, asi como con el estandar sensitivo Yeerongpilly, se valoraron cuantitativamente en varios ambitos de exposicion los grados de reaccion de los acaricidas, que no inhiben la colinesterasa, clenpirina, clordimeformo y clormetiuron, estable-ciendo los cocientes de concentraciones que reducen la capacidad de reproduccion de las estirpes resistentes a los PE y del estandar de referencia Yeerongpilly en un 50%. Asi se pudo probar, sin lugar a dudas, que las estirpes Biarra, Mackay y Mt. Alford, resistentes a los PE, no han desarrollado por ahora ninguna resistencia contra clenpirina, clordimeformo y clormetiuron. Se pudo comprobar en todas las estirpes una dilacion temporal en la oviposicion y en el desarrollo embrionario bajo la accion de clordimeformo y clormetiuron.

R. Gothe - One of the best experts on this subject based on the ideXlab platform.

  • Zur ixodiziden Wirksamkeit von Clenpyrin, Chlordimeform und Chlormethiuron gegen PE‐resistente Boophilus microplus‐Stämme
    Zentralblatt fur Veterinarmedizin. Reihe B. Journal of veterinary medicine. Series B, 2010
    Co-Authors: R. Gothe, M. Hartig
    Abstract:

    Zusammenfassung Durch in vitro Untersuchungen mit weiblichen Zecken der PE-resistenten Stamme Biarra, Mackay und Mt. Alford sowie dem sensitiven Standard Yeerongpilly wurden die Reaktionslagen fur die Cholinesterase nicht hemmenden Akarizide Clenpyrin, Chlordimeform und Chlormethiuron durch Festlegung der Quotienten aus Konzentrationen, die die Vermehrungskapazitat der PE-resistenten Stamme und des Bezugsstandards Yeerongpilly um 50% einschrankt, in verschiedenen Expositionsbereichen quantitativ bestinimt. Dabei konnte eindeutig nachgewiesen werden, das die PE-resistenten Stamme Biarra, Mackay und Mt. Alford bisher noch keine Resistenz gegenuber Clenpyrin, Chlordimeform und Chlormethiuron entwickelt haben. Eine zeitliche Verzogerung der Eiablage sowie der Embryonalentwicklung konnte bei allen Stammen nur unter der Einwirkung von Chlordimeform und Chlormethiuron festgestellt werden. Summary On the ixodicidal activity of Clenpyrin, Chlordimeform and Chlormethiuron against OP-resistant Boophilus microplus strains By in vitro investigations with female Boophilus microplus ticks of organophosphorus-resistant strains Biarra, Mackay and Mt. Alford as well as the sensitive strain Yeerongpilly, the degree of resistance against the cholinesterase non-blocking acaricides Clenpyrin, Chlordimeform and Chlormethiuron was quantitated by determination of the quotient from concentrations reducing the capacity of reproduction by 50% in different ranges of exposure. The results of the present experimental study show clearly that the organophosphorus resistant strains Biarra, Mackay and Mt. Alford had not developed any resistance against Clenpyrin, Chlordimeform and Chlormethiuron. A temporary retardation in oviposition as well as in embryonic developments in all strains could only be observed after treatment with Chlordimeform and Chlormethiuron. Resume A propos de l'action ixodicide de “Clenpyrin”, “Chlordimeform” et “Chlormethiuron” sur des souches de Boophilus microplus PE-resistantes On a determine in vitro et quantitativement dans differentes situations d'exposition les reactions a des acaricides non inhibiteurs de la cholinesterase (Clenpyrine, Chlordimeform et Chlormethiuran) chez des tiques femelles des souches resistantes Biana, Mackay, Mt. Alford et de la souche sensible Standard Yeerongpilly, en etablissant le quotient des concentrations qui limitaient a 50% la capacite de reproduction des souches PE-resistantes et du standard Yeerongpilly. On a pu demontrer de facon certaine que les souches PE-resistantes Biana, Mackay et Mt. Alford n'avaient developpe aucune resistance a Clenpyrine, Chlordimeform et Chlormethiuron. Seule l'action de Chlordimeform et Chlormethiuron provoqua un ralentissement temporaire de la ponte et du developpement embryonnaire. Resumen La potencia ixodicida de clenpirina, clordimeformo y clormetiuron frente a estirpes de Boophilus microplus resistentes a los esteres del acido fosforico (PE) Mediante estudios in vitro con garrapatas hembras de las estirpes resistentes a esteres del acido fosforico (PE) Biarra, Mackay y Mt. Alford, asi como con el estandar sensitivo Yeerongpilly, se valoraron cuantitativamente en varios ambitos de exposicion los grados de reaccion de los acaricidas, que no inhiben la colinesterasa, clenpirina, clordimeformo y clormetiuron, estable-ciendo los cocientes de concentraciones que reducen la capacidad de reproduccion de las estirpes resistentes a los PE y del estandar de referencia Yeerongpilly en un 50%. Asi se pudo probar, sin lugar a dudas, que las estirpes Biarra, Mackay y Mt. Alford, resistentes a los PE, no han desarrollado por ahora ninguna resistencia contra clenpirina, clordimeformo y clormetiuron. Se pudo comprobar en todas las estirpes una dilacion temporal en la oviposicion y en el desarrollo embrionario bajo la accion de clordimeformo y clormetiuron.

  • zur ixodiziden wirksamkeit von clenpyrin Chlordimeform und chlormethiuron gegen pe resistente boophilus microplus stamme
    Journal of Veterinary Medicine Series B-infectious Diseases and Veterinary Public Health, 2010
    Co-Authors: R. Gothe, M. Hartig
    Abstract:

    Zusammenfassung Durch in vitro Untersuchungen mit weiblichen Zecken der PE-resistenten Stamme Biarra, Mackay und Mt. Alford sowie dem sensitiven Standard Yeerongpilly wurden die Reaktionslagen fur die Cholinesterase nicht hemmenden Akarizide Clenpyrin, Chlordimeform und Chlormethiuron durch Festlegung der Quotienten aus Konzentrationen, die die Vermehrungskapazitat der PE-resistenten Stamme und des Bezugsstandards Yeerongpilly um 50% einschrankt, in verschiedenen Expositionsbereichen quantitativ bestinimt. Dabei konnte eindeutig nachgewiesen werden, das die PE-resistenten Stamme Biarra, Mackay und Mt. Alford bisher noch keine Resistenz gegenuber Clenpyrin, Chlordimeform und Chlormethiuron entwickelt haben. Eine zeitliche Verzogerung der Eiablage sowie der Embryonalentwicklung konnte bei allen Stammen nur unter der Einwirkung von Chlordimeform und Chlormethiuron festgestellt werden. Summary On the ixodicidal activity of Clenpyrin, Chlordimeform and Chlormethiuron against OP-resistant Boophilus microplus strains By in vitro investigations with female Boophilus microplus ticks of organophosphorus-resistant strains Biarra, Mackay and Mt. Alford as well as the sensitive strain Yeerongpilly, the degree of resistance against the cholinesterase non-blocking acaricides Clenpyrin, Chlordimeform and Chlormethiuron was quantitated by determination of the quotient from concentrations reducing the capacity of reproduction by 50% in different ranges of exposure. The results of the present experimental study show clearly that the organophosphorus resistant strains Biarra, Mackay and Mt. Alford had not developed any resistance against Clenpyrin, Chlordimeform and Chlormethiuron. A temporary retardation in oviposition as well as in embryonic developments in all strains could only be observed after treatment with Chlordimeform and Chlormethiuron. Resume A propos de l'action ixodicide de “Clenpyrin”, “Chlordimeform” et “Chlormethiuron” sur des souches de Boophilus microplus PE-resistantes On a determine in vitro et quantitativement dans differentes situations d'exposition les reactions a des acaricides non inhibiteurs de la cholinesterase (Clenpyrine, Chlordimeform et Chlormethiuran) chez des tiques femelles des souches resistantes Biana, Mackay, Mt. Alford et de la souche sensible Standard Yeerongpilly, en etablissant le quotient des concentrations qui limitaient a 50% la capacite de reproduction des souches PE-resistantes et du standard Yeerongpilly. On a pu demontrer de facon certaine que les souches PE-resistantes Biana, Mackay et Mt. Alford n'avaient developpe aucune resistance a Clenpyrine, Chlordimeform et Chlormethiuron. Seule l'action de Chlordimeform et Chlormethiuron provoqua un ralentissement temporaire de la ponte et du developpement embryonnaire. Resumen La potencia ixodicida de clenpirina, clordimeformo y clormetiuron frente a estirpes de Boophilus microplus resistentes a los esteres del acido fosforico (PE) Mediante estudios in vitro con garrapatas hembras de las estirpes resistentes a esteres del acido fosforico (PE) Biarra, Mackay y Mt. Alford, asi como con el estandar sensitivo Yeerongpilly, se valoraron cuantitativamente en varios ambitos de exposicion los grados de reaccion de los acaricidas, que no inhiben la colinesterasa, clenpirina, clordimeformo y clormetiuron, estable-ciendo los cocientes de concentraciones que reducen la capacidad de reproduccion de las estirpes resistentes a los PE y del estandar de referencia Yeerongpilly en un 50%. Asi se pudo probar, sin lugar a dudas, que las estirpes Biarra, Mackay y Mt. Alford, resistentes a los PE, no han desarrollado por ahora ninguna resistencia contra clenpirina, clordimeformo y clormetiuron. Se pudo comprobar en todas las estirpes una dilacion temporal en la oviposicion y en el desarrollo embrionario bajo la accion de clordimeformo y clormetiuron.

Celia Maqueda - One of the best experts on this subject based on the ideXlab platform.

  • adsorption desorption of Chlordimeform on montmorillonite effect of clay aggregation and competitive adsorption with cadmium
    Environmental Science & Technology, 1999
    Co-Authors: Tomas Undabeytia, Esmeralda Morillo, Shlomo Nir, Tamara Polubesova, Giora Rytwo, Celia Maqueda
    Abstract:

    Effect of the aggregation state of montmorillonite clays of types SAz-1 and SWy-1 on the adsorption of the monovalent organic cation Chlordimeform was studied. The shapes of the adsorption isotherms were related to the degree of dispersion of the clay, changing from S- to L-type by decreasing clay concentration. Unlike monovalent organic cations denoted dyes, Chlordimeform adsorption did not exceed the cationic exchange capacity of the clay (CEC). At larger Ca2+/Na+ charge ratio (≈0.5), Chlordimeform exhibited low apparent affinity for adsorbing to the SAz-1 clay, due to steric inhibition of its penetration between closely opposed clay platelets. The apparent affinity increased dramatically at smaller Ca2+/Na+ charge ratios (<0.06) for Ca2+-montmorillonite, or by switching to Na+-montmorillonite. The desorption process of Chlordimeform shows an apparent hysteresis in Ca2+-montmorillonite. An adsorption model which combines electrostatic equations with specific binding in a closed system is able to account...

  • Adsorption-desorption of Chlordimeform on montmorillonite : Effect of clay aggregation and competitive adsorption with cadmium
    Environmental Science & Technology, 1999
    Co-Authors: Tomas Undabeytia, Esmeralda Morillo, Shlomo Nir, Tamara Polubesova, Giora Rytwo, Celia Maqueda
    Abstract:

    Effect of the aggregation state of montmorillonite clays of types SAz-1 and SWy-1 on the adsorption of the monovalent organic cation Chlordimeform was studied. The shapes of the adsorption isotherms were related to the degree of dispersion of the clay, changing from S- to L-type by decreasing clay concentration. Unlike monovalent organic cations denoted dyes, Chlordimeform adsorption did not exceed the cationic exchange capacity of the clay (CEC). At larger Ca2+/Na+ charge ratio (≈0.5), Chlordimeform exhibited low apparent affinity for adsorbing to the SAz-1 clay, due to steric inhibition of its penetration between closely opposed clay platelets. The apparent affinity increased dramatically at smaller Ca2+/Na+ charge ratios (

  • Clay Minerals (1996) 31,485M-90 ADSORPT ION OF Co AND ZN ON MONTMORILLONITE IN THE PRESENCE OF A CAT IONIC PEST IC IDE
    1996
    Co-Authors: Esmeralda Morillo, Celia Maqueda
    Abstract:

    ABSTRACT: The adsorption of Cd and Zn on a standard montmorillonite (SAZ-1) in the presence of the cationic pesticide Chlordimeform, both in solution (simultaneous adsorption) and when the pesticide is previously adsorbed on the clay (successive adsorption) has been studied. The adsorption of Zn decreases when the Chlordimeform concentration increases in both simultaneous and successive adsorptions, following the sequence: Chlordimeform-free solutions> successive> simultaneous. In the adsorption of Cd the sequence is different: successive> Chlordimeform-free solutions> simultaneous, indicating that a small amount of pesticide adsorbed favours Cd adsorption. In all cases, the apparent affinity of the metal for adsorption on montmorillonite, on the basis of distribution coefficients, Ko, is higher for lower metal surface coverage, and decreases largely with the amount of the metal adsorbed. This indicates the existence of high affinity sites on the clay, probably those of variable charge edge regions. The contribution of edge and interlamellar positions to adsorption of Zn and Cd on SAZ-1 has been studied. The persistence of agrochemicals and heavy metals in soils depends mainly on the adsorption

  • Simultaneous adsorption of Chlordimeform and zinc on montmorillonite
    Science of The Total Environment, 1992
    Co-Authors: Esmeralda Morillo, Celia Maqueda
    Abstract:

    Abstract The competitive adsorption of the cationic pesticide Chlordimeform and the heavy metal zinc on montmorillonite was studied. For different concentrations of Zn used, Chlordimeform decreases (in relation to Zn-free treatments) when the pesticide is adsorbed simultaneously with the metal, but increases when Zn is adsorbed previously to Chlordimeform. When comparing the K D values Chlordimeform is shown to have a higher affinity for montmorillonite when there is a previous adsorption of Zn than with the simultaneous adsorption of Zn and the pesticide. The adsorption of Zn decreases when Chlordimeform concentration increases, in both cases, when the metal is adsorbed simultaneously with the pesticide and when Chlordimeform has been previously adsorbed to Zn.

Esmeralda Morillo - One of the best experts on this subject based on the ideXlab platform.

  • adsorption desorption of Chlordimeform on montmorillonite effect of clay aggregation and competitive adsorption with cadmium
    Environmental Science & Technology, 1999
    Co-Authors: Tomas Undabeytia, Esmeralda Morillo, Shlomo Nir, Tamara Polubesova, Giora Rytwo, Celia Maqueda
    Abstract:

    Effect of the aggregation state of montmorillonite clays of types SAz-1 and SWy-1 on the adsorption of the monovalent organic cation Chlordimeform was studied. The shapes of the adsorption isotherms were related to the degree of dispersion of the clay, changing from S- to L-type by decreasing clay concentration. Unlike monovalent organic cations denoted dyes, Chlordimeform adsorption did not exceed the cationic exchange capacity of the clay (CEC). At larger Ca2+/Na+ charge ratio (≈0.5), Chlordimeform exhibited low apparent affinity for adsorbing to the SAz-1 clay, due to steric inhibition of its penetration between closely opposed clay platelets. The apparent affinity increased dramatically at smaller Ca2+/Na+ charge ratios (<0.06) for Ca2+-montmorillonite, or by switching to Na+-montmorillonite. The desorption process of Chlordimeform shows an apparent hysteresis in Ca2+-montmorillonite. An adsorption model which combines electrostatic equations with specific binding in a closed system is able to account...

  • Adsorption-desorption of Chlordimeform on montmorillonite : Effect of clay aggregation and competitive adsorption with cadmium
    Environmental Science & Technology, 1999
    Co-Authors: Tomas Undabeytia, Esmeralda Morillo, Shlomo Nir, Tamara Polubesova, Giora Rytwo, Celia Maqueda
    Abstract:

    Effect of the aggregation state of montmorillonite clays of types SAz-1 and SWy-1 on the adsorption of the monovalent organic cation Chlordimeform was studied. The shapes of the adsorption isotherms were related to the degree of dispersion of the clay, changing from S- to L-type by decreasing clay concentration. Unlike monovalent organic cations denoted dyes, Chlordimeform adsorption did not exceed the cationic exchange capacity of the clay (CEC). At larger Ca2+/Na+ charge ratio (≈0.5), Chlordimeform exhibited low apparent affinity for adsorbing to the SAz-1 clay, due to steric inhibition of its penetration between closely opposed clay platelets. The apparent affinity increased dramatically at smaller Ca2+/Na+ charge ratios (

  • Clay Minerals (1996) 31,485M-90 ADSORPT ION OF Co AND ZN ON MONTMORILLONITE IN THE PRESENCE OF A CAT IONIC PEST IC IDE
    1996
    Co-Authors: Esmeralda Morillo, Celia Maqueda
    Abstract:

    ABSTRACT: The adsorption of Cd and Zn on a standard montmorillonite (SAZ-1) in the presence of the cationic pesticide Chlordimeform, both in solution (simultaneous adsorption) and when the pesticide is previously adsorbed on the clay (successive adsorption) has been studied. The adsorption of Zn decreases when the Chlordimeform concentration increases in both simultaneous and successive adsorptions, following the sequence: Chlordimeform-free solutions> successive> simultaneous. In the adsorption of Cd the sequence is different: successive> Chlordimeform-free solutions> simultaneous, indicating that a small amount of pesticide adsorbed favours Cd adsorption. In all cases, the apparent affinity of the metal for adsorption on montmorillonite, on the basis of distribution coefficients, Ko, is higher for lower metal surface coverage, and decreases largely with the amount of the metal adsorbed. This indicates the existence of high affinity sites on the clay, probably those of variable charge edge regions. The contribution of edge and interlamellar positions to adsorption of Zn and Cd on SAZ-1 has been studied. The persistence of agrochemicals and heavy metals in soils depends mainly on the adsorption

  • Simultaneous adsorption of Chlordimeform and zinc on montmorillonite
    Science of The Total Environment, 1992
    Co-Authors: Esmeralda Morillo, Celia Maqueda
    Abstract:

    Abstract The competitive adsorption of the cationic pesticide Chlordimeform and the heavy metal zinc on montmorillonite was studied. For different concentrations of Zn used, Chlordimeform decreases (in relation to Zn-free treatments) when the pesticide is adsorbed simultaneously with the metal, but increases when Zn is adsorbed previously to Chlordimeform. When comparing the K D values Chlordimeform is shown to have a higher affinity for montmorillonite when there is a previous adsorption of Zn than with the simultaneous adsorption of Zn and the pesticide. The adsorption of Zn decreases when Chlordimeform concentration increases, in both cases, when the metal is adsorbed simultaneously with the pesticide and when Chlordimeform has been previously adsorbed to Zn.

Maqueda Porras Celia - One of the best experts on this subject based on the ideXlab platform.

  • Simultaneous adsorption of Chlordimeform and zinc on montmorillonite
    'Elsevier BV', 2013
    Co-Authors: Morillo González Esmeralda, Maqueda Porras Celia
    Abstract:

    The competitive adsorption of the cationic pesticide Chlordimeform and the heavy metal zinc on montmorillonite was studied. For different concentrations of Zn used, Chlordimeform decreases (in relation to Zn-free treatments) when the pesticide is adsorbed simultaneously with the metal, but increases when Zn is adsorbed previously to Chlordimeform. When comparing the KD values Chlordimeform is shown to have a higher affinity for montmorillonite when there is a previous adsorption of Zn than with the simultaneous adsorption of Zn and the pesticide. The adsorption of Zn decreases when Chlordimeform concentration increases, in both cases, when the metal is adsorbed simultaneously with the pesticide and when Chlordimeform has been previously adsorbed to Zn.Peer Reviewe

  • Adsorption of Chlordimeform by humic substances from different soils
    'Ovid Technologies (Wolters Kluwer Health)', 2013
    Co-Authors: Maqueda Porras Celia, Pérez Rodríguez, José Luis, Morillo González Esmeralda, Justo Ángel
    Abstract:

    We studied the interaction of the cationic pesticide Chlordimeform with humic and fulvic acids from different soils. The mechanism of Chlordimeform adsorption is essentially a cation exchange reaction. Adsorption is influenced by the origin of the humic substances because of the different content in functional groups. Fulvic acids adsorb in lower proportion than humic acids from the same soil, despite the higher content in functional groups.Peer Reviewe

  • Mutual influence of Cu and a cationic herbicide on their adsorption-desorption processes on two selected soils
    'Springer Science and Business Media LLC', 2012
    Co-Authors: Undabeytia López Tomás, Morillo González Esmeralda, Ramos, Blas Antonio, Maqueda Porras Celia
    Abstract:

    Adsorption of Cu and the cationic herbicide Chlordimeform was carried out on two acidic soils (S-48 and LM). Chlordimeform adsorption occurred by cationic exchange and was higher on LM soil due to its higher CEC, partly associated to the presence of vermiculite. Cu adsorption was also higher on LM soil and was related to its higher iron and manganese oxides content. The presence of the herbicide in solution always decreased Cu adsorption on S-48 soil, but on LM soil the amount of Cu adsorbed only decreased at the highest concentrations used. This together with the lower amounts of Cu desorbed from LM soil after five successive desorptions in comparison to S-48 soil, indicates that Cu was being mostly adsorbed on oxides which exhibit a very high affinity for the heavy metal. The maximal amount of Cu desorbed on both soils only reached up to 13% of the amount adsorbed. Chlordimeform adsorption decreased in the presence of Cu as a result of its competition for the adsorption sites on both soils. Cu competition on LM soil was not so strong as on S-48 soil due to the higher adsorption of the heavy metal on oxides, for which the herbicide's affinity is not so high. The lower the amounts of Chlordimeform adsorbed on both soils the higher its desorption percentage. This was attributed to steric impediment of Chlordimeform molecule itself for the desorption from lamellar silicates.The authors acknowledge the Comisión Interministerial de Ciencia y Tecnología (CICYT) for financial support (Project N. AMB97-0692). Dr. Undabeytia acknow- ledges the Spanish Government for a research contract (Project N. AMB98-0888).Peer Reviewe

  • Simultaneous adsorption of cadmium and a cationic pesticide on montmorillonite
    'Informa UK Limited', 2012
    Co-Authors: Undabeytia López Tomás, Morillo González Esmeralda, Maqueda Porras Celia
    Abstract:

    The competitive adsorption of the cationic pesticide Chlordimeform and the heavy metal cadmium on montmorillonite was studied. For the different pesticide concentrations used, cadmium adsorption decreases with increasing Chlordimeform concentration, indicating a high competition between both cations for interlamellar positions. In contrast, pesticide adsorption increases in the presence of Cd2+ in relation to Cd‐free treatments. This adsorption is independent of metal concentration used, and therefore adsorption isotherms are practically the same in all cases where cadmium is present.Peer Reviewe

  • Interaction of pesticides with the soluble fraction of natural and artificial humic substances
    'Informa UK Limited', 2012
    Co-Authors: Maqueda Porras Celia, Morillo González Esmeralda, Undabeytia López Tomás
    Abstract:

    The adsorption of two cationic pesticides on the soluble part of natural and artificial humic substances, and their mechanisms of interaction, have been studied using the equilibrium dialysis method. Paraquat and Chlordimeform in diverse concentrations have been used. A natural fulvic acid extracted from a spodosol soil, a commercial humic acid and polymaleic acid were used as comparison. Chlordimeform adsorption data from this work are higher than those obtained in a previous paper without dissolving the humic substances. Paraquat isotherms always present values lower than Chlordimeform ones. Natural fulvic acid adsorbs more than the commercial humic substance for both pesticides. The results show that acidified soluble fraction of the commercial HA is more similar to natural FA than polymaleic acid. However the latter is generally used as a model for fulvic acid. The interaction mechanisms between these humic substances and cationic pesticides were principally cation-exchange processes, but H-bonding and charge transfer mechanisms are also possible, as shown by IR study.Peer Reviewe