In this work, the determination of moving averages is proposed as a method for quantifying metal, arsenic, and sulfate discharges into a water course undergoing acid mine drainage processes which flows into a public water supply dam in the Iberian Pyrite Belt. The analysis of the results obtained by applying moving averages shows that the highest metal and sulfate concentrations occur in October, coinciding with the first rainfall and the sponging of mine dumps, with November and December being the months when the highest contributions to the Andevalo Dam take place. The discharge of acid mine waters with its corresponding metal load into the Andevalo Dam means, for a single hydrological year, more than 6,000 t of sulfates, almost 600 t of iron, and 1 t of As, of special relevance for the hydrochemical quality of the stored waters. When they arrive at the dam, these metals precipitate, since the water pH is near 7, and remain latent in the bottom sediment as long as the chemical makeup of the dam water does not change.
The Iberian Pyrite Belt (SW Spain) is a highly relevant source of Acid Mine Drainage contamination on a global scale. Although the Tinto and Odiel Rivers, which cross the Iberian Pyrite Belt, have been widely studied by various authors, an issue is still pending: the study of the metal load distribution undergone by each of these rivers and, hence, the establishment of cause-effect relationships between the transported load in the final sections of both rivers, upstream of the tidal influence limits, and the characteristics of the input in each of the basins. To solve this, a water sampling campaign was conducted on both rivers on a daily basis from mid September 2007 to the end of May 2008, where pH, conductivity, redox potential, As, Cd, Fe, Cu, Zn, Mn and sulfate were analyzed. The results were treated with the PreFurGe tool, which is based on Fuzzy Logic. This showed that the order of abundance for the parameters analyzed for the Odiel River is SO 4 >Zn>Mn>Fe>Cu>Cd>As, whereas for the Tinto River it is SO 4 >Fe>Cu>Zn>Mn>Cd>As. This last pattern coincides with the order of abundance of elements in Pyrite. In the Tinto River, the metal with the highest rate is Fe, which presents mean values of 361.1 mg/L, whereas in the Odiel River iron mean concentration is 5.34 mg/L. This difference is due to higher precipitation of oxyhydroxysulfates of iron in the Odiel River as a result of the higher intensity of neutralization processes.
<p>La conexión entre las matemáticas y la realidad que nos rodea se ejecuta por medio de actividades de la resolución de problemas contextualizados en nuestro entorno de vida. No hay que olvidar que la Matemática ha evolucionado a través de la historia a partir del planteamiento y el abordaje de problemas; estos dos procesos, que podemos resumir como resolución de problemas, han impulsado su enorme crecimiento y, lo que es más importante, caracterizan la labor del matemático como tal. Ante una situación problemática real, un resultado numérico no tiene sentido desligado del contexto, es necesario darle sentido teniendo en cuenta las condiciones impuestas por la situación. Pero numerosas investigaciones ponen de manifiesto que los estudiantes se limitan a obtener un resultado numérico que dan como solución sin considerar el contexto (Greer, 1993; Silver, 1992). La modelización matemática se entiende como el proceso por el cual se interpreta matemáticamente situaciones para tomar algún tipo de decisión lo que implica centrarse en elementos de la situación, sus relaciones, patrones y características, teniendo como producto un modelo en algún nivel de sofisticación con relación al propósito. Siguiendo a Schoenfeld presentaremos algunos ejemplos concretos de situaciones (problemas) desarrolladas con alumnos/as de Secundaria, que bien pueden extrapolarse a alumnos/as de niveles superiores donde se expondrán las diferentes fases y heurísticos por las que debemos pasar cuando nos enfrentamos a un problema. También abordaremos algunas consideraciones teóricas en torno al Aprendizaje Basado en Problemas (ABP) como uno de los métodos de enseñanza-aprendizaje que ha tomado más arraigo en las instituciones de educación superior en los últimos años.</p>
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