ESPOCH Congresses: The Ecuadorian Journal of S.T.E.A.M.
ISSN: 2789-5009
Leading Ecuadorian research in science, technology, engineering, arts, and mathematics.
Application of Sustainable Remediation Techniques for Heavy Metal Reduction in Polluted Rivers in Mining Zones: Study Area Ponce Enriquez
Published date: Nov 09 2023
Journal Title: ESPOCH Congresses: The Ecuadorian Journal of S.T.E.A.M.
Issue title: Volume 3 Issue 1
Pages: 248–268
Authors:
Abstract:
Mining activity in Ecuador is primarily artisanal and small-scale. Rivers near the mining county of Camilo Ponce Enriquez have been severely affected by this type of mining. A field study was conducted encompassing 29 sites on the rivers Siete, Fermin, and Pagua during sampling campaigns that took place in both dry (December) and wet seasons (February). Physiochemical parameters and heavy metal concentrations were measured to enable environmental characterization of the rivers. Results revealed that most of the sampled sites had bad water quality and exceeded the environmental limits of heavy metal concentrations set by the Ecuadorian government. A parallel pilot investigation was performed for reducing the heavy metal concentrations in water ecosystems polluted by mining activities using bioremediation techniques. The bioremediation technique applied in the study used bacteria from a wastewater digestor and sugarcane bagasse as a carbon source to support the bacterial community. Sulfide was measured to monitor bacterial activity in experimental bioreactors containing local acid mine drainage (AMD). The results obtained were encouraging, as a significant decrease in heavy metal concentration was observed to nearly the level of Ecuadorian environmental regulations for Al, Cd, Cu, Fe, Pb, and Zn concentrations in freshwater in a set of bioreactors.
Keywords: acid drainage, artisanal mining, bioremediation, heavy metals, pollution.
Resumen
La actividad minera en el Ecuador es principalmente artesanal y de pequeña escala. Los ríos cercanos al área minera de Camilo Ponce Enríquez se han visto severamente afectados por este tipo de minería. Se realizó un estudio de campo en 29 sitios sobre los ríos Siete, Fermín y Pagua durante campañas de muestreo que se realizaron tanto en la época seca (diciembre) como en época húmeda (febrero). Se midieron parámetros fisicoquímicos y concentraciones de metales pesados para permitir la caracterización ambiental de los ríos. Los resultados revelaron que la mayoría de los sitios muestreados tienen agua de mala calidad y excedieron los límites ambientales de concentración de metales pesados establecidos por el gobierno ecuatoriano. También se realizó una investigación piloto paralela destinada a reducir las concentraciones de metales pesados en ecosistemas acuáticos contaminados por actividades mineras utilizando técnicas de biorremediación. La técnica de biorremediación aplicada en el estudio utilizó bacterias de un digestor de aguas residuales y bagazo de caña de azúcar como fuente de carbono para apoyar a la comunidad bacteriana. Se midió el sulfuro para controlar la actividad bacteriana en biorreactores experimentales que contenían drenaje ácido minero (AMD) local. Los resultados obtenidos son alentadores ya que en un conjunto de biorreactores se observó una disminución significativa de las concentraciones de algunos metales pesados alcanzando casi en su mayoría el nivel permisible según las regulaciones ambientales ecuatorianas para las concentraciones de Al, Cd, Cu, Fe, Pb y Zn en agua dulce.
Palabras Clave: drenajes ácidos, minería artesanal, biorremediación, metales pesados, contaminación.
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