26/11/2015
The results of analyses commissioned by Samarco after the accident with SGS Geosol Laboratorios, a company specialized in environmental and geochemical analyses of soils, confirm that the tailings from the Fundão dam do not represent any hazard to people. The samples were collected on November 8th, at points close to Bento Rodrigues, Monsenhor Horta, Pedras, Barretos and Barra Longa, in Minas Gerais, and analyzed pursuant to Brazilian standard ABNT NBR 10004:2004. These sites were chosen for the collection of the samples due to their close proximity to the accident, thus making them more representative of the material that was contained in the dam.
The tests simulate several situations, such as handling of the tailings by any person without special precautions, exposure to rain for several years and contact with running water, such as torrents. The material was also analyzed to measure its level of acidity, neutrality or alkalinity (pH), its corrosiveness and the possibility of generating a violent reaction such as an explosion. In addition, the material was tested for the presence of the following substances: aluminum, arsenic, barium, cadmium, lead, cyanide, chloride, copper, chrome, iron, fluorides, manganese, mercury, nitrate, silver, selenium, sodium, sulfate, zinc, phenols, coagulants and flocculants.
After the analyses of all these parameters, the tailings found in Bento Rodrigues, Monsenhor Horta, Pedras, Barretos and Barra Long were classified as non hazardous. This means that the material analyzed does not present any risk to human health, as it does not contain elements which may contaminate water, even with exposure to continued rainfall.
The results further show that the tailings collected in Bento Rodrigues contain iron and manganese at levels above the reference values of said standard, but still below the levels considered hazardous. However, in the samples collected close to Monsenhor Horta, Pedras, Barretos and Barra Longa, the presence of manganese was detected outside established parameters, yet still below hazardous levels. As in the general region of Mariana and Ouro Preto the soil is rich in both these two elements, these results were to be expected. It is important to point out that the standard ABNT 10004:2004 uses reference values based on the reality of Brazil as a whole, including regions which have soils poor in iron and manganese.
