Analysing the effects two decades after a mining spill

There has been an important fall in the total concentrations and evolution of the metal fraction towards their more innocuous forms, so the environmental risk is much reduced. The samples were taken in the same locations and by the same research group twenty years later. Sediments were analysed from six locations on the River Guadiamar and its main tributaries, from the area of the Aznalcóllar mine to the gates of Doñana national Park.