The failure of the tailings dam of the mining company Samarco on November 5, 201, in the municipality of Mariana, Minas Gerais, was, without a doubt, one of the greatest environmental disasters in our country's history. The impacts arising from the release of the sludge affected several ecosystems, which will probably take tens of years to recover.
→ What happened in Mariana?
In November 2015, one of Samarco's tailings dams, the Fundão dam, ruptured and caused the release of a large amount of sludge. This mud, capable of filling more than 20,000 Olympic swimming pools, left a huge trail of destruction.
When released, the mud caused the destruction of several houses and also the death of people living in nearby areas and some employees of the mining company. The most affected district was Bento Rodrigues, which was practically covered by mud.
→ Does the released mud harm health?
According to mining company Samarco, the mud released in the accident is not toxic and contains only water, sand and iron oxide. Despite apparently not causing harm 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 non-toxic, how has it affected the environment?
The large amount of mud released in the accident is not toxic, but it has triggered a series of environmental imbalances. The first one was the coverage of the region by tailings. As this material is poor in organic matter, probably no plant species will be able to develop on the site. In addition, the mud can cause changes in the soil, making it difficult for species that did not die from the accident to remain. It is also worth noting that, when it dries, the mud will harden, making it difficult for vegetables to grow and the ecosystem to reestablish.
The mud also reached the rivers in the region, causing the death of the species that lived there. You fish, which were used for food and even as a source of income, gradually died due to decreased oxygen and obstruction of their gills, structures responsible for breathing these animals.
It is worth noting that it is not just the fish that have 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 collapse of the dams.
Death was not only perceived within the rivers, as a large amount of riparian forest (vegetation that is on the banks of rivers) was completely destroyed in some areas. Many plant species were uprooted by the force of the mud, and others were completely buried.
Samarco's mud can also cause the siltation of rivers, reduction of depth in some areas, diversion of water courses and even the burial of springs. It is also expected that, upon reaching the sea via the Doce River, the mud will contaminate aquatic environments and also cause damage to marine life.
→ How can environmental accidents be avoided?
In order for accidents like the one that happened in Mariana to be avoided, it is very important to carry out detailed analyzes of the environmental impacts that an undertaking can cause. It is important to assess all environmental factors before, during and after construction 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 carried out cautiously and all irregularities must be corrected quickly and effectively.
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