Examinando por Autor "Posada-Posada, M. I. (Martha Isabel)"

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  • Miniatura
    PublicaciónAcceso abierto
    Efectos del mercurio sobre algunas plantas acuáticas tropicales
    (2014-05-08) Posada-Posada, M. I. (Martha Isabel); Arroyave-Maya, M. P. (Maria del Pilar)
    This paper describes the effects of mercury on some aquatic plants of the tropics and their habitats. Additionally, a protocol for toxicity tests in duckweed (Lemna minor) is recommended, and the results of preliminary tests with salts of mercury under laboratory conditions are given. It was found that mercury is in different toxicity and bioavailability forms depending on the factors that facilitate the solubilization of this element in the water. Many plants act as bioindicators because they withhold the metal selectively, while others are bioaccumulators since they tolerate and accumulate them in their structures producing biomagnification through the food web. The preliminary tests carried out in Lemna minor suggest that the appropriate concentrations for the toxicity tests are between 0,01 mg/L and 10,0 mg/L for Hg.
  • Miniatura
    PublicaciónAcceso abierto
    Influencia de la vegetación en los niveles de ruido urbano
    (2013-11-26) Posada-Posada, M. I. (Martha Isabel); Arroyave-Maya, M. P. (Maria del Pilar); Fernández-Ossa, C. E. (Carlos Eduardo)
    The objective of the study was to assess the capacity of vegetation to reduce the noise in the Aburrá valley. The methodology comprised two phases: the first was the revision of secondary information related to the role of vegetation and to obtain the conceptual bases for further experimental development. The second phase was the measurement of noise levels 10 m from the sound source (high traffic road) in urban public green zones with different plant coverage (tree, shrub, and a mixture of trees and shrubs) and without vegetation. Results showed no significant differences between the sites with and without vegetation, allowing us to infer that under conditions of the study, characterized by having few individuals of trees and shrubs dispersed, the vegetation does not play a significant role in reducing noise. Therefore, for its control in urban areas measures other than the planting of trees must be taken, or wider, longer, denser, and higher live barriers should be established.