Wildlife still largely absent from red sludge area: WWF

"Wildlife and fishlife were totally devastated or displaced from the area, and six months later, the banks of rivers Marcal and Torna are still red," WWF said in a statement.

Ten people were killed last October when the retaining walls of a reservoir at the alumina plant in Ajka in western Hungary burst, sending 1.1 million cubic metres (38.8 million cubic feet) of poisonous, stinking red-coloured mud across an area of 40 square kilometres (15 square miles).

The sludge wiped out almost all waterlife in rivers and streams in the immediate vicinity and even spread to the Danube.

Work was continuing to remove the toxic sediment from river banks in the area, according to the mayor of one of the hardest-hit villages, Devecser.

The authorities initially declared a statement of emergency in the area for a period of six months. But that has now been extended while the clean-up work and repair to the dam walls continues, the authorities said.

(c) 2011 AFP