The river

Rio Tinto is one of those places on Earth that make you think that you have landed in another planet.

The name “Rio Tinto” means in Spanish Red River. The reason of the river’s colour is because of the weathering of heavy metals that the river finds during his course and the reaction with bacteria like Acidithiobacillus ferrooxidans. There is a high presence of Sulfuric Acid and this produces an extremely acid river, with pH between 1.7 and 2.5. Even so, there are some communities of microorganisms that live from the oxidation and don’t require the solar light to survive.

Those discoveries have inspired NASA and ESA to investigate this environment and try there the equipment for the next Mars missions.

The  mine

Due to the richness of minerals in that area, it has been exploited during the last 5.000 years, until today. From there were extracted: copper, gold, silver, zinc, lead, pyrite and sulfur.

The mining activity has caused a big and evident impact to this environment. The scraps that remain after the cleaning and treatment of the minerals are very dangerous and very complicated to manage. The waste was stocked in big holding dam that finally broke.

One of the holding dams near Rio Tinto broke on 25th April 1998, releasing a big amount of mine tailings and producing one of the biggest ecological disasters in the history of Spain: Doñana disaster or Aznalcollar Disaster.

Polluted waters and toxic sludge invaded the river and reached to the natural park of Doñana. It was severe contamination due to metals such as arsenic, cobalt, chromium, copper, mercury, manganese, nickel, lead, tin, uranium and zinc; that abounded in discharges.