The Bento Rodrigues Dam in Brazil collapsed on November 5, 2015...The dam had been used to store water and mineral waste from a nearby iron-ore mine. It had no alarm system and no good emergency plan or designated evacuation routes. According to the villagers, nobody was warned about the breach. “If the dam had collapsed at night, everyone would have died,” said Duarte Júnior, the mayor of the city that includes Bento Rodrigues.The dam was operated by Samarco, a joint venture between two multinational mining companies: Brazil’s Vale and the Anglo-Australian BHP Billiton. More than a month after the dam collapsed, it is unclear how long it will take for the ecosystem — and the economy — to recover. And two more dams in the area are at risk of collapsing.
After flooding the village, the wave of approximately 2.2 billion cubic feet of mud and mineral residue, enough to fill about 25,000 Olympic-size swimming pools, made its way to the Doce River. The river, which passes through 228 municipalities, is crucial to the region’s economic life. The mineral-waste sludge has devastated the area. Several companies had to suspend operations. Local fishermen are among the most severely affected. The water supply for Governador Valadares, a city of 300,000 people, had to be cut off for a week.
The companies involved insist that the muck poses no threat to human health. But two United Nations environmental experts declared that the mud contained “high levels of toxic heavy metals and other toxic chemicals.” A report from the Institute for Water Management, a government agency in the state of Minas Gerais, found that the water’s arsenic levels were 10 times above the legal limit. Other samples collected at different points along the river contained high levels of mercury, iron, aluminum and manganese.
According to Ibama, Brazil’s environmental protection agency, the Doce River is home to 80 fish species, of which 11 are endangered and 12 are found nowhere else in the world…. The mud’s brown route across Brazil’s waterways is visible in NASA satellite images. Sixteen days after the dam broke, the tide reached the Atlantic Ocean, more than 400 miles downstream. It also spread into the Comboios Biological Reserve on the coast, a spawning area for loggerhead sea turtles and critically endangered leatherback sea turtles. “The steps taken by the Brazilian government, Vale and BHP Billiton to prevent harm were clearly insufficient,” the United Nations environmental experts said in a statement, adding that it was unacceptable that it took three weeks for information about the water’s toxicity to surface. “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 said.
The exact cause of the breach has not yet been determined. Samarco’s chief executive officer suggested that a seismic tremor near the mine may have caused it, but public prosecutors suspect negligence by the company. Brazil’s press is criticizing the federal government in Brasília for failing to monitor the dam. The National Department of Mineral Production employed only four people in the whole state of Minas Gerais to inspect 735 dams.
Excerpt from Vanessa Barbara, Brazil’s Toxic Sludge, NY Times, Dec. 17, 2015