In the early morning of April 25, 1998, the dam of the pond burst with toxic discharges from the Aznalcóllar mine (Seville) and only the work of the tractors of the rice farmers, who built an emergency wall, prevented the arrival in Doñana of four cubic hectometres of acid water and another two of sludge loaded with heavy metals.

The rupture of the pond belonging to the Boliden Apirsa company released acidic waters and toxic sludge containing arsenic, cadmium, mercury and other heavy metals onto the Agrio and Guadiamar rivers, causing their riverbeds to overflow and flooding the surrounding lands. along an extension of 62 kilometers.

In total, 4,634 hectares of agricultural and pasture areas in Aznalcóllar, Olivares, Sanlúcar la Mayor, Benacazón, Huévar, Aznalcázar, Villamanrique de la Condesa, Isla Mayor and La Puebla del Río were affected. All this while Seville celebrated its April Fair.

The sludge sedimented in the first 40 kilometers of the channel with a thickness that exceeded three meters in the vicinity of the pond and reached several centimeters at the entrance to the marshes. The acid waters reached the lower section of Entremuros and were retained at the gates of the Doñana National Park.

The collected ones were deposited in the Aznalcóllar pit. In the first six months, 80 percent of the spilled sludge was collected, but the spillage had penetrated some large diameter wells located in the aquifer that were pumped and to which lime was added. to neutralize the acidity. On the day of the spill, the fish were jumping out of water whose pH was similar to that of a car battery.

At that time, the central government was in the hands of the PP and the Junta de Andalucía in those of the PSOE. The first moments involved an open confrontation between the two administrations and until three years later mining in the area did not stop and the affected area, which was dedicated to agricultural work, was expropriated.

Despite the confrontation, the Urgent Measures Plan was created, activated by a Mixed Coordination Commission, in which both administrations were involved, in order to provide a solution to the two main fronts: removing the sludge and cleaning up the volume of water toxin retained in containment dikes.

A treatment plant was built on the dams through which the Guadalquivir Hydrographic Confederation (CHG) removed heavy metals from the water and controlled the pH. After normalizing the state of the water, they were discharged into the Guadalquivir Estuary, and during the following weeks a control of the quality of the water, both surface and underground, was carried out, as well as a monitoring of the air quality and the state of the beings. alive.

The Commission also launched two initiatives to revitalize the area: ‘Doñana 2005’, from the Ministry of the Environment, and ‘El Corredor Verde del Guadiamar’, from the Junta de Andalucía, which was declared a Protected Landscape and attached to the Network of Protected Natural Areas of Andalusia in April 2003. It was not until 2001 that researchers located the turning point at which the animal populations in the environment began to recover.

On the 25th anniversary of the ecological disaster, which could have been even worse, the trial to determine the responsibility for the spill has not yet been held. It is set for a little less than three months – it starts on July 4 – and the Swedish Boliden Apirsa has managed to get away, for now. of any type of responsibility, both criminal and civil.

The Andalusian Government figures the money allocated to the recovery of the Guadiamar between 1998 and 2003 at 89.8 million euros, whose work focused on two large areas: 1,800 hectares of the Entremuros marshes, within the Doñana natural area, affected by floodwaters acid, and the 3,000 hectares of the fluvial plain.

During the investigation, the Swedish multinational assures that the economic impact suffered by the company due to that spill was 115 million and that a total of 80 million have already been allocated to the “voluntary” removal of the sludge, something that caused it to enter a tender of creditors as a result of the expenses caused by the spill.

For its part, the Board, as plaintiff, bases its claim on Article 81 of the Mining Law, which holds the operator responsible for damages caused by their work by infringing the requirements established to protect the environment, and considers that Boliden did not complete the cleaning of the area, something that the Swedish multinational rejects, considering that the application of this article is a “legal construction”.

The balance of this ecological disaster is seven million cubic meters of mud removed; 30 tons of dead animals; contaminated aquifers; world record for heavy metal concentration in waterfowl; economic losses valued at around 120 million euros, and according to a study by the Universities of Granada and Almería, 7% of the affected land still has high levels of heavy metals such as arsenic or lead.

The legislation also evolved as a result of the Aznalcóllar disaster with the Environmental Responsibility Law of 2007, which regulates responsibility, basically under the principle that “those who pollute pay”.

Aznalcóllar served to develop a general application standard on soil contamination in the EU that did not exist until now and there were no emergency plans or security procedures.

And in the middle of the judicial labyrinth, the municipality of Aznalcóllar asks for a solution that allows the reopening of the mine, which could employ a thousand people.

The Board began the procedures in 2015 due to the interest of several companies to take over the exploitation, but one of the companies that had entered into the competition appealed the award of the project, denouncing various irregularities, which led to the initiation of another judicial process.

Organizations such as Ecologistas en Acción, Greenpeace, SEO/BirdLife or WWF consider the reopening of the mine unfeasible and seek a transition that allows a balance between the environmental and the economic reactivation of the region.

However, from the Junta de Andalucía, now in the hands of the PP, considers that the reopening will increase the important weight of the Andalusian mining sector.