Brazilian mine disaster releases dangerous metals

The collapse in November of a mining dam in the Brazilian state of Minas Gerais, which resulted in the inundation of a whole town under a sea of mud contaminated with toxic iron ore waste and silica, was one of the country's worst environmental disasters.

Luisa Massarani

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Both the mine operator (a joint venture between mining giants BHP Billiton and Vale) and the Brazilian authorities have come under fire from UN rapporteurs for their negligence in failing to take measures to avert the accident.

THE environmental disaster that has followed the collapse of a dam at a Brazilian mine on 5 November has caused unprecedented damage in that country and will have irreversible negative effects on human health and the environment, according to experts.

The accident buried the small historic town of Bento Rodrigues, a subdistrict of Mariana, under mud. At least 11 people have died and more than 600 were displaced. In addition, the water supply of more than 250,000 people in the area was interrupted as it was contaminated with heavy metals.

Tonnes of mud made up of iron ore waste and silica, originally estimated to be about 25,000 Olympic swimming pools in volume, have spread over 800 km and reached one of the largest Brazilian rivers, the Rio Doce. The contaminated mud, in which the Minas Gerais Institute of Water Management has found toxic substances like mercury, arsenic, chromium and manganese at levels exceeding drinking water limits, has reached the coast of the state of Espirito Santo. It could potentially impact the wider marine ecosystem.

The risks go beyond the particular chemical elements found in this mud. Dam water was also contaminated with harmful bacteria.

Many are blaming the disaster on Samarco, which is the Brazilian mining company in charge of the dams. The company is a joint venture between the mining giants Vale of Brazil and BHP Billiton of Australia.

More dams at risk

Although it was initially announced that two dams had collapsed in the mine, representatives of the National Department of Mining Production surveyed that area by air and have confirmed that only the Fundao dam collapsed. They warned, however, that Samarco's Santarem dam has been 'overrun' and remains at risk of collapse, as does the company's Germano dam.

'As there was never an environmental incident of this magnitude, it is impossible to calculate the real impact right now,' says Klemens Laschefski, a researcher at the Federal University of Minas Gerais.

'The changes in the flow of the river in respect to the currents and the new geochemical conditions in the sediments will bring profound ecosystem changes, which will also influence the species, including with the possibility of disappearance of endemic species,' Laschefski warns. In addition, he says water plants in the area are endangered because the mud that now covers them will eventually harden like cement, due to its high iron content.

Aloysio da Silva Ferrao Filho, a researcher at the Oswaldo Cruz Foundation, agrees that the situation is dire. 'The entire ecosystem is under threat and the impacts can even reach the marine food chain, possibly even the Abrolhos coral reefs, which are quite sensitive to sedimentation of inorganic material,' he told Chemistry World.

Ferrao says these effects can last for decades. He says the high concentrations of heavy metals in the water samples from the Rio Doce could lead to the bioaccumulation of metals in the food chain, and possibly reach toxic levels in some organisms.

Biodiversity lost

'The biodiversity of the river is completely lost,' Ferrao states. 'Several species, including endemic ones, must be extinct.' Although some recovery must be expected through restocking from other tributaries, he says it is impossible to estimate how long such reclamation would take.

Several investigations are underway to determine the causes of the disaster, including one by federal and state prosecutors, and others by the Brazilian Institute for the Environment and an independent group of researchers.

Samarco states that several small seismic tremors that occurred in the area could have caused the dam damage, but some experts point to negligence on the part of the company and the government bodies responsible for overseeing the mine.

For example, Laschefski states that the risks of rupture of the Fundao dam, and the lack of a contingency plan for such a scenario, were well documented back in 2013. Nevertheless, he says that Samarco has not taken measures to address such threats, and actually increased its waste production.

On 11 November, the CEOs of Vale and BHP Billiton jointly pledged to support Samarco in creating an emergency fund to rebuild damaged infrastructure and provide relief for those affected by the disaster. In fact, Samarco representatives signed an agreement with state and federal prosecutors on 16 November to pay at least $250 million to cover emergency measures.

On 13 November, a judge in Mariana granted an injunction freezing $75 million in Samarco's bank account to provide for reparations to local victims of the accident. The previous day, Brazilian President Dilma Rousseff had confirmed a $62.5 million fine for the mining company, announcing that other fines could be forthcoming.                    

This article is reproduced from the website of Chemistry World (www.rsc.org/chemistryworld), the print and online magazine of the Royal Society of Chemistry.

'This is not the time for defensive posturing' - UN rights experts TWO United Nations independent experts on environment and toxic waste on 25 November called on the government of Brazil and relevant businesses to take immediate action to protect the environment and health of communities at risk of exposure to toxic chemicals in the wake of the catastrophic collapse of a tailing dam on 5 November. 'This is not the time for defensive posturing,' said the UN Special Rapporteur on human rights and the environment, John Knox, and the Special Rapporteur on human rights and hazardous substances and wastes, Baskut Tuncak. 'It is not acceptable that it has taken three weeks for information about the toxic risks of the mining disaster to surface.' 'The steps taken by the Brazilian government, Vale and BHP Billiton to prevent harm were clearly insufficient. The Government and companies should be doing everything within their power to prevent further harm, including exposure to heavy metals and other toxic chemicals,' they stressed. New evidence shows the collapse of a tailing dam belonging to a joint venture of Vale and BHP Billiton (Samarco Mining SA) released 50 million tons of iron ore waste containing high levels of toxic heavy metals and other toxic chemicals in the Doce River. Hospitals in Mariana and Belo Horizonte, the capital city of Minas Gerais State, have received several patients. 'The scale of the environmental damage is the equivalent of 20,000 Olympic swimming pools of toxic mud waste contaminating the soil, rivers and water system of an area covering over 850 kilometres,' Knox warned. The expert noted that the Doce River, one of Brazil's great watersheds, 'is now considered by scientists to be dead and the toxic sludge is slowly working its way downstream towards the Abrolhos National Marine Park where it threatens protected forest and habitat. Sadly the mud has already entered the sea at Regencia beach, a sanctuary for endangered turtles and a rich source of nutrients that the local fishing community relies upon.' 'The Brazilian authorities should assess whether Brazil's laws for mining are consistent with international human rights standards, including the right to information,' said Tuncak, who recently presented a special report on the right to information in the context of hazardous substances to the UN Human Rights Council. 'Under international human rights standards, the State has an obligation to generate, assess, update and disseminate information about the impact to the environment [of] hazardous substances and waste, and businesses have a responsibility to respect human rights, including conducting human rights due diligence,' the expert stressed. The Special Rapporteurs stated that 'this disaster serves as yet another tragic example of the failure of businesses to adequately conduct human rights due diligence to prevent human rights abuses.' 'There may never be an effective remedy for victims whose loved ones and livelihoods may now lie beneath the remains of [the] tidal wave of toxic tailing waste, nor for the environment which has suffered irreparable harm,' they said. 'Prevention of harm must be at the centre of the approach of business whose activities involve hazardous substances and wastes.' - Office of the UN High Commissioner for Human Rights

*Third World Resurgence No. 303/304, November/December 2015, pp 4-5