Lessons in toxic waste must be learnt from Brazilian mudslide

Written by: Richard Hurdle | Published:
Richard Hurdle

On 1 February 2019, a dam storing Iron ore mining tailings collapsed in southeast Brazil.

The sludge rapidly slid towards the town of Brumadinho and eventually covered an area the size of 300 football pitches and engulfed nearby houses, buildings, vehicles and roads.

The human cost is clear, with at least 121 killed and 232 missing, presumed dead, but there is also concern for how to deal with the 12 million cubic metres of contaminated mud that was released.

Authorities fear the metal-laced slurry released by the collapse could eventually pollute the Sao Francisco River, the second-longest in Brazil, which hosts various species of fish and has many towns located on its banks.

Immediate effect

Tests carried out by Brazil's national water agency ANA in the Paraopeba tributary, muddied along 200 kilometres (120 miles) by the dam burst, show that the presence of heavy metals in the water have spiked to unhealthy levels.

An immediate concern is the damaging effect the sludge will undoubtably have on the drinking supply and local wildlife.

The waste sediments will strip oxygen from the water, kill fish, and in turn, create serious issues for the local community. The chances of local residents, plants, surviving fish and other wildlife being exposed to toxic accumulations of substances such as Cadmium, Arsenic or Mercury from the drinking supply, irrigation of crops, or food chain is highly likely.

Vale, the mining company responsible for the dam, has announced plans to deal with the debris. These include building barriers to contain the mud in the area around the dam, dredging a section of the nearby river and constructing barriers to sift out the fine residue.

Learning from the past

This latest spill echoes a similar incident which took place in 2015 when an iron ore tailings dam in Mariana, Minas Gerais, Brazil, suffered a catastrophic failure, resulting in flooding that destroyed the village of Bento Rodrigues and killed 19 people.

The aftermath of this disaster is still felt today, four years on, with an ongoing investigation; and the resulting waste expected to take decades to dilute to anywhere near normal levels.

Ultimately, Brazil needs to learn from the efforts made by UK authorities following a catastrophic release of 45m litres of acidic water from the Wheal Jane mine into the Carnon River in Cornwall.

Subsequent action was taken by UK authorities to prevent further incidents at the site, which included the creation of round-the-clock pumps to neutralise the acidity of the contaminated water, coupled with placing the remaining sludge into clay-lined impermeable lagoons away from the clean water, protecting the wildlife and members of the local community as a result.

Looking to the future

The efforts made prove that measures can be put in place to stop incidents like this happening both here in the UK and internationally. The Vale dam was being monitored but there was an obvious absence of accountability, and emergency planning which is required by European legislation

The Brumadinho dam had passed safety inspections. Five people involved in the inspections have been arrested as part of an investigation to find out whether the process was fraudulent.

Good practice must also be observed to make sure toxic sludge is contained and doesn’t continue to contaminate areas in the future. Filtration plants will need to be built to provide an alternative water supply for affected locals, although this will be a costly operation to set up that the Brazilian government may not have the budget for.

In the most recent Brazilian mudslide case, responsibility falls to the mining company to alter their methods by looking at successful stories such as the Wheal Jane mine in Cornwall.

However, there are serious concerns that other companies are using the same tactics to mine and this will eventually lead to similar incidents recurring in the not so distant future, potentially causing further detrimental impact to the Brazilian environment.

Richard Hurdle is managing director of Chloros Environmental


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