RIO DE JANEIRO, April 6 (Reuters) - Alumina do Norte do Brasil, or Alunorte, on Thursday sued prosecutors in the Brazilian state of Para, pushing for a new water quality study to assess a spill by the company there.
Alunorte, a unit of Norway's Norsk Hydro, operates the world's biggest alumina refinery in Barcarena in the state. Local residents and Brazilian authorities accused the company of causing a toxic leak in February that polluted the water supply.
The company has admitted to dumping untreated rainwater from the refinery but has pushed back against accusations of serious contamination.
The authorities asked the government-backed Evandro Chagas Institute, a public health research organization, to conduct a study of the water supply in response to the complaints. The study determined that Alunorte had contaminated the nearby waters with heavy metals.
Alunorte, which has questioned the validity of the institute's scientific work, sued state prosecutors on Thursday in the hopes that the court would require them to hire another consultancy to conduct a fresh study.
A new study should "develop a sampling plan according to established legal standards and the necessary scientific rigor," Hydro Legal Director Hans Martin Heikvam told Reuters on Thursday.
The spat over the study caused talks between prosecutors and the company to break down earlier this week, Heikvam said.
"We are now asking the court to continue discussions with the prosecution on a correct factual basis," Heikvam said.
The Para state prosecutors office said they had not been informed of any legal action by Alunorte, but said that negotiations had indeed broken down in part due to the study.
The company's criticism of the study "does not demonstrate that the data is wrong and disregards the fact that the company itself has admitted to routinely dumping effluents without any treatment," said the prosecutors office.
Alumina is a compound extracted from bauxite ore that is then smelted to form aluminium. (Reporting by Marta Nogueira; Writing by Alexandra Alper; Editing by Christian Schmollinger)