A torrent of mud unleashed by a dam burst at an iron ore mine in southeastern Brazil is contaminating the Atlantic Ocean.

Brazilian officials say thousands of hectares of land and water has been contaminated by the "country's worst environmental catastrophe ever", what's worse is that Brazil's Environment Minister Izabella Teixeira has predicted that it may take up to 30 years to get rid of the toxic sludge from the Doce basin.

On Nov. 5 about 60 million cubic metres of iron ore waste which could fill 25,000 Olympic-size swimming pools, engulfed Bento Rodrigues and Paracatu and contaminated the river, which is the primary source of clean water and food in the region.

The deadly stain of red mud, water and debris from the Nov. 5 burst at the Samarco mine in the Minas Gerais state all but erased a hamlet there, killing eight people, with another four bodies still unidentified and 21 missing.The mud flowed downstream into the Rio Doce ('Sweet [Water] River'), where it devastated wildlife and compromised the drinking water source for hundreds of thousands of people.The stain flowed through the neighboring Espirito Santo state, reaching the Atlantic over the weekend.

A report Monday in O Estado de S. Paulo daily said the mud had reached a sensitive nature reserve frequented by endangered turtles.

Brazil's government said previously on Nov 11 that it may fine mining giants BHP Billiton Ltd and Vale SA for the "environmental catastrophe" caused by ruptured dams at an iron ore mine jointly owned by the companies in a southeastern state.The government is increasingly concerned over the rising death toll and contaminated mud flowing through two states as a result of the disaster. It is studying the mine's permits and will ensure the owners pay for cleanup costs, Environment Minister Izabella Teixeira said in Brasília, the capital."If federal fines are applicable, we will apply them," Teixeira told reporters. "There will be punishment, and under Brazilian law the environment has to be repaired."The warning came as the chief executives of Australia-based BHP, the world's largest mining company, and Brazil's Vale, the world's biggest iron ore miner, took responsibility for the disaster.After surveying the devastated area together, BHP CEO Andrew Mackenzie and Vale CEO Murilo Ferreira told a news conference their companies would meet all their obligations as joint owners of the mine, which is formally run by Samarco Mineração SA."We are 100 percent committed to do everything we can do to support Samarco and make this right," Mackenzie said. "We are deeply sorry for everyone who has or will suffer for this terrible tragedy."The apologies, however, are not doing much to calm nerves. More than 500 people remain displaced because of destroyed homes, and recovery crews are slogging through nearly 100 km (62 miles) of mud-caked floodplain in a search for more victims.Fernando Pimentel, the governor of Minas Gerais, said on Wednesday the companies were not doing enough to address the problems caused by the disaster, including the interruption of water service for hundreds of thousands of residents downstream.Water from the dams that burst contained mining residue known as tailings."Samarco, to blame for all of this, will have to make a greater effort," Pimentel told reporters in Governador Valadares, a city of 300,000 residents that is now having its water trucked in.Known for her harsh reprimands of opponents and subordinates, President Dilma Rousseff told the CEOs that she expected Vale and BHP to cover all environmental and reconstruction costs as well as pay compensation to displaced families.

The conversation was "tough", a presidential press aide told Reuters. To reinforce her message, Rousseff asked her chief of staff, Jaques Wagner, to meet with the companies' executives.Neither the companies nor Brazilian officials have determined a cause for the ruptures, though Samarco acknowledged that workers, 13 of whom were washed away by the torrent, were engaged in an expansion of the first dam when it burst. The work was necessary because of increased output at the mine.A state prosecutor on Wednesday said investigators are probing reports that Vale contributed to higher water volumes behind the dam by sending waste from one of its nearby mines to Samarco's tailings pond. When a reporter asked about the reports at the news conference, the executives did not answer.The disaster has become a public relations, regulatory and financial nightmare for the companies. Politicians, environmentalists and residents are calling for tougher rules on the mining industry, which employs hundreds of thousands of people and is a major source of export revenue.A person familiar with the insurance framework around the mine said on Tuesday that the disaster could trigger $600 million in insurance claims.The mine employs about 1,800 workers, most of whom are now on paid leave as operations have been halted.