Since the Samarco tailings dams collapsed on 05 November 2015, over fifty million cubic metres of toxic sludge have swept down the valley and into the Rio Doce, through the Brazilian state of Espírito Santo and out to sea at the Rio Doce estuary at Regência in Linhares district.
Brazil’s Worst-ever Environmental Disaster
Climate News Network say that the sludge has contaminated the water supply of a dozen towns along its course and left behind a desolate landscape of dead fish and wildlife, uprooted trees, and a thick layer of solidified mud. Some media reports are calling it the “death of the Rio Doce”.
Scientists said this was Brazil’s worst-ever environmental disaster.
“The loss of habitat is enormous, and the damage to the ecosystem is irreversible”, said Marcus Vinicius Polignano, an environmental health lecturer at UFMG, the Federal University of Minas Gerais.
“Besides iron ore and other metals, the mud, which invaded houses and fields, brought sewage, pesticides and dead animals, which accelerate the production of algae and bacteria.“
Governor of of Espírito Santo, Paul Hartung, has requested the support of the Brazilian navy to monitor the mouth of the Rio Doce and collect water samples, in order to monitor the level of contamination of the sea.
Brazil’s Minister of the Environment, Helen Teixeira, said there is little risk of the mud reaching the Abrolhos Archipelago, a group of 5 small islands with coral reefs off the southern coast of Bahia state, about 250 km from Linhares. The extensive reefs of the island group are an area of rich marine fauna. The uninhabited islets are a breeding ground for pelagic birds. The minister said that the preliminary data suggests that the mud will disperse around six kilometres out to sea.
There are some fears that the current drought in Brazil has meant that levels of the Rio Doce are still too low to carry away all the toxic mud. Scientists fear the Doce’s low volume means a lot of the mud will end up as silt on the riverbed, instead of being carried downstream and dispersed into the ocean. In August the river fell so low it did not reach the sea, but ended up trickling into a sandbank; in some places it was only 3 cm deep.