UPDATE 2-Mud from Brazil dam burst is toxic, UN says
* Residue contained toxic heavy metals and chemicals -UN
* UN statement contradicts claims by Samarco, BHP
* Fish choking to death on heavy volume of sediment -BHP (Adds BHP comments)
RIO DE JANEIRO, Nov 25 (Reuters) - Mud from a dam that burst at an iron ore mine in Brazil earlier this month, killing 12 people and polluting an important river, is toxic, the United Nations' human rights agency said on Wednesday.
The statement contradicts claims by Samarco, the mine operator at the site of the rupture, and Samarco's co-owner, BHP Billiton , that the water and mineral waste contained by the dam are not toxic.
Citing "new evidence," the UN's Office of the High Commissioner for Human Rights said in a statement the residue "contained high levels of toxic heavy metals and other toxic chemicals".
The agency did not identify the studies that were the basis for the evidence or say who conducted them, and a spokesman in Geneva was not immediately available for comment.
The owners of Samarco, Brazil's Vale SA and Australia's BHP, said they are taking every measure possible to provide emergency assistance to those affected by the dam break and to reduce the social and economic impacts of the disaster.
Samarco said in a statement that both pre- and post-disaster tests show the mud released in the dam burst, made up mostly of water, iron oxides and silica or quartz, presents no danger to human health and does not contain water contaminants. Continuación...