Understand the environmental damage of the accident in Mariana, one of the biggest environmental disasters in the country.

The rupture of the tailings dam of the mining company Samarco on November 5, 201, in the municipality of Mariana, Minas Gerais, was undoubtedly one of the greatest environmental disasters in the history of our country. The impacts resulting from the release of the mud have affected several ecosystems , which are likely to take tens of years to recover.

→ What happened in Mariana?

In November 2015, one of Samarco’s tailings dams, the Fundão dam, broke and caused the release of a large amount of mud. This mud, capable of filling more than 20 thousand Olympic swimming pools, left a great trail of destruction.

Upon being released, the mud caused the destruction of several houses and also the death of people who lived in nearby areas and of some employees of the mining company. The most affected district was Bento Rodrigues, which was practically covered by mud.

→ Does the released mud cause damage to health?

According to mining company Samarco, the sludge released in the accident is non-toxic and contains only water, sand and iron oxide. Although, apparently, it does not cause damage to human health, this mud, when reaching rivers, makes the water unfit for consumption, besides, of course, causing several material losses.

→ If the mud is not toxic, how did it affect the environment?

The large amount of sludge released in the accident is not toxic, but it has triggered a series of environmental imbalances. The first was the coverage of the region by tailings. Since this material is low in organic matter, probably no plant species will be able to grow on the site. In addition, the mud can cause changes in the soil, making it difficult for the species that did not die with the accident to remain. It is also worth noting that, when it dries, the mud will become hard, making it difficult for plants to grow and restore the ecosystem.

The mud also reached the rivers of the region, causing the death of the species that lived there. The fish , which served as food and even as a source of income, gradually died due to the decrease in oxygen and the obstruction of their gills, structures responsible for the breathing of these animals.

It is worth noting that it is not just the fish that died as a result of the mud. In many regions of the river, it is possible to see that the entire aquatic ecosystem has been destroyed. The Doce River, one of those affected, will probably take ten years to recover from all the damage caused by the rupture of the dams.

Death was not only perceived within rivers, as a large amount of riparian forest (vegetation on the banks of rivers) has been completely destroyed in some areas. Many plant species were uprooted by the force of the mud, and others, completely buried.

Samarco’s mud can also cause the silting up of rivers, decrease in depth in some areas, diversions of water courses and even burial of springs. It is also expected that, when it reaches the sea through the Doce River, the mud will contaminate aquatic environments and also cause damage to marine life.

→ How can environmental accidents be avoided?

For accidents like what happened in Mariana to be avoided, it is very important that detailed analyzes of the environmental impacts that a project can cause are made. It is important to assess all environmental factors before, during and after the construction of a work.

It is also necessary to analyze what measures can be taken by a company if an environmental damage of this proportion occurs. In addition, inspection must be done cautiously and all irregularities must be corrected quickly and effectively.


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