Niveles de contaminación por metales pesados en el acuífero aluvial del Agrio en el entorno minero de Aznalcóllar (Sevilla) durante el periodo 2012-2018

Abstract

In year 1998, the rupture of the Aznalcóllar (Seville) mine-tailing dam caused an avenue of pyritic mud and acid water in the Agrio River that caused the degradation of the fluvial ecosystem. After the cleaning activities, sealing of the tailing dam and other recovery measures, the quality of the Agrio River water has improved considerably. However, the results of the hydrochemical studies that have been carried out in the area, published between 2005 and 2010, have detected contamination to the Agrio and Guadiamar rivers from the dam. In the present work, measurements of the piezometric level, pH, temperature and electrical conductivity of groundwater have been made from 2012 to 2018 in piezometers of the area near the mine and also in the Agrio River, as well as a sampling campaign of dissolved metals in groundwater and surface water in February 2018. The results indicate that, although pollution levels have been decreasing since 1998, there is still contamination to the Agrio.