Tibor Dobson, a spokesman for Hungarian disaster crews, said there were no reports of fish death in the Raba and Mosoni-Danube rivers affected by the spill earlier, but all fish had died in the smaller Marcal River, which was hit first.
Crews were working to reduce the alkalinity of the spill, which poured from the containment reservoir of an alumina plant on Monday and tore through local villages, killing four people and injuring over 150. Three people were still reported missing.
The spill’s alkaline content when it reached the Raba and Mosoni-Danube was still around pH 9 — above the normal, harmless level of between 6 and 8, Dobson said.
Gabor Figeczky, Hungarian branch director of the WWF environmental group who visited the scene along with experts, said the impact on the river Marcal was worse than expected and it was hoped the alkalinity would drop once it reached the Raba, a bigger river. But it was still between pH 9 and 10, he said.
Figeczky told Reuters that since the Danube was a much larger river, the alkalinity should dilute. He said pH levels should normally be between 7 and 8, ideally closer to 7.
“Based on our current estimates, it (pollution) will remain contained in Hungary, and we also trust that it will reach Budapest with acceptable pH values,” he added.
Downstream from the disaster site, the Danube flows through or touches on Croatian, Serbian, Bulgarian, Romanian, Moldovan and Ukrainian territory en route to the Black Sea.
Hungary declared a state of emergency in three counties on Tuesday after the sludge — waste from bauxite refining that has a strong caustic effect — hit Kolontar, Devecser and other villages 160 km (100 miles) west of Budapest.
Prime Minister Viktor Orban visited Kolontar on Thursday and said there was no point in even removing the rubble from part of the village as it was impossible to live there again.
“It is difficult to find the words. Had this happened at night, everybody would be dead,” Orban told reporters.
He said the disaster could not have had natural causes.
“This is an unprecedented ecological catastrophe in Hungary. Human error is more than likely. The wall (of the reservoir) did not disintegrate in a minute. This should have been detected.”
MAL Zrt, owner of the Ajkai Timfoldgyar alumina plant and burst reservoir, said on Tuesday there had been no sign of the impending disaster, adding that the last inspection of the reservoir on Monday had shown nothing wrong.
Disaster crews, military and local villagers were clearing away the rubble and searching for the three missing people.
Many people suffered from burns and eye ailments caused by the caustic effect and corrosive elements in the mud. The flood, estimated at about 700,000 cubic meters (24 million cubic feet), swept cars off roads and damaged bridges and houses.
On Tuesday the government suspended production at the plant and police were investigating what may have caused the disaster.
MAL reiterated on Thursday that it would like to restart production at its alumina plant at the weekend with a new sludge containment pond.
Lajos Tolnay, chairman of MAL, told business daily Vilaggazdasag that if the company were to stop operation, 3,000 jobs would be lost at the firm and at business partners.
He said the plant could safely resume operations.
But many people in Kolontar said they would not move back to their houses as they did not feel secure.
“I hung in the sludge for 45 minutes... It had a strong current that almost swept me away but I managed to hang on to a strong piece of wood of the pigsty,” said Etelka Stump.
“But I could hardly breathe because that air, that smell, that froth really hit me. I know what it’s like because I worked in the bauxite factory for 17 years.”
