Farming to be affected by sludge from collapsed dam, survey shows

The soil in the regions affected by the sludge that leaked after a Samarco dam burst in Mariana, Minas Gerais, does not provide the appropriate conditions for agricultural development. The conclusion was drawn by the Brazilian Corporation of Agricultural Research, or EMBRAPA, in a survey commissioned by the state government.

The research began on November 18 and included samples from 10 sites in regions reached by the mud in Minas Gerais.

Even though the presence of heavy metals in the samples was not seen to have reached toxic levels, the report shows that the soil's fertility has been compromised. Problems resulting from the sudden appearance of a layer of sediment near the surface were also observed.

According to laboratory examinations, the sediment does not show the conditions necessary for the germination of seeds or the development of roots.

EMBRAPA's study reveals a reduction in the levels of potassium, magnesium, and calcium in the soil—all of which fundamental to farming-related activities. The pH, which shows how acid the soil is, was also seen to have changed. The soil is now likely to become compact due to stronger presence of rock and fine sand fragments, with low levels of clay.

To solve the problem, the Company for Technical Assistance and Rural Extension of Minas Gerais State, Emater-MG, recommends intense reforestation action in all of the areas affected by the sludge, which should show results in a few years.

In a partnership with the city government, Emater-MG has devised a plan of action including visits to farmers affected. Questionnaires are being used in order to ascertain the losses sustained by the field workers, which are under the responsibility of Samarco and the t venture's owners, mining companies Vale and BHP Billiton.

Translated by Fabrício Ferreira