River running through Brumadinho shows high level of heavy metals

Other river basis are under risk by contamination in the Paraopeba

Published in 06/03/2019 - 18:15 By Camila Boehm - São Paulo

The level of copper in the Paraopeba river is up to 600 times the amount allowed in rivers used for human consumption, irrigation for food production, fishing, and leisure activities. This is yet another consequence of the rupture of Vale’s mining dam in Brumadinho, in the southeastern state of Minas Gerais.

The acceptable limit for copper is 0.009 milligrams a liter (mg/l), but the rate soared from 2.5 to 5.4 mg/l in the 22 samples collected in an expedition along 305 km of the Paraopeba for a Fundação SOS Mata Atlântica report, released in São Paulo Wednesday (Feb. 27).

The document concludes that the Paraopeba river lost its status as an important public source of supply and multiple water uses as a result of the 14 tons of mining waste dragged to the bottom of the river following the collapse of the Córrego do Feijão dam complex, controlled by mining giant Vale.

In the report, 112 hectares of native forests are said to have been devastated by the flood of waste that followed the breach. Of these, 55 hectares were part of well preserved areas.

“The metals we found [in the Paraopeba] were iron, copper, manganese—metals that are not harmful to human health in small amounts. The difference between the dose and the remedy is the dose. They become toxic due to the amount we find in the water, way above what’s set by law,” said biologist Marta Marcondes, professor and coordinator at the Laboratory for Environmental Analysis at the Municipal University of São Caetano do Sul (USCS).

Also detected was chromium level 42 times higher than acceptable under the law (0.05 mg/l). In this dosage, chromium may even cause mutagenic effects and death.

Life in the river

Throughout the stretch covered by the expedition, indicators gauged in the water—including oxygen and turbidity levels—also revealed water not suitable for life. Of the 22 criteria considered, ten showed poor results, and 12 were reported as very poor.

The high turbidity rate—the amount of material in the water that makes it difficult for light to enter—the excess of decomposing nutrients and the high temperatures registered in the water, among other factors scrutinized, led to low dissolved oxygen rates, not in compliance with the standards for class 2 rivers (used for supply, irrigation, and fishing), fixed at 5 mg/l. In one of the criteria analyzed, oxygen reached 1.3 mg/l, lower than required for life under water.

“Water is unfit for use, and the Minas Gerais state decree must be observed—no one should use the river water, because it’s risky,” warned Malu Ribeiro, specialist in water resources with the Fundação SOS Mata Atlântica.

Other sources of pollution that had their effect aggravated after the collapse include bacteria from decomposing matter, untreated or semi-treated sewage, and even pesticides.

“The river was already receiving such pollutants, but it had a greater dilution capacity, so it was able to clean the river from these contaminating substances. When the waste came flooding in, the first thing this mud did was block the river, so it lowered the water level and concentrated pollutants it already had and brought new ones,” Ribeiro said. She mentioned sewage from households, stables, and farms.

Captação de água no Paraopeba
The Paraopeba is among the 15 main rivers forming the São Francisco basin. It accounted for 43 percent of public supply in the metropolitan region of Belo Horizonte, comprising 15 municipalities, including Brumadinho - Copasa


Deadlines must be carefully set for the restoration of the river Paraopeba, Ribeiro argued. “First, we have to wait for victims to be located, which is still underway, so the soil in the Brumadinho region is still being moved for the bodies to be found. Meanwhile, the waste is being spread across the environment, and whenever it rains and waste is dragged along, it heads for the river. So it’s still impossible to plan any changes to the river bed,” she declared.

After this early stage, this waste should be removed and taken to a land-filled site. Monitoring the river, Ribeiro said, is crucial to keeping track of water conditions and predicting when Paraopeba will be able to have fish re-introduced and serve the local community again.

The specialist noted that the river Doce is still not recovered and that coast and sea water is still affected three years after the rupture of the dam in Mariana, also in Minas Gerais. “The recovery of riparian forests, springs, and tributaries flowing into Paraopeba in good quality are crucial to developing a river capable of regenerating,” Ribeiro pointed out.

“More than ever, the efforts to restore the São Francisco river need to get off the paper, and now that includes the restoration of the Paraopeba. The Paraopeba is the river forming the São Francisco. If it reaches the Três Marias reservoir sick, it’s as if poison was dripping into the São Francisco river every day,” she added.

The Paraopeba is among the 15 main rivers forming the São Francisco basin. It accounted for 43 percent of public supply in the metropolitan region of Belo Horizonte, comprising 15 municipalities, including Brumadinho.

The São Francisco river starts in Minas Gerais, in Brazil’s Southeast, and runs 2,830 km as far as Alagoas state, in the Northeast, where it pours into the Atlantic ocean. At least 530 Brazilian municipalities rely on the water from the river and the energy generated by the hydroelectric plants on it. Três Marias is the first on this line of power plants and is also located in Minas Gerais.

Translation: Fabrício Ferreira -  Edition: Kleber Sampaio / Nira Foster

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