The River Danube was apparently absorbing Hungary's toxic red sludge spill with little immediate harm, officials reported today.
The spill, triggered when a reservoir burst, dumped 158 million to 184 million gallons of sludge onto three villages - slightly less in a few hours than the 200 million gallons the blown-out BP oil well gushed into the Gulf of Mexico over several months, the government said.
The death toll rose to five when an 81-year-old man died this morning from injuries sustained in the flooding
"The consequences do not seem to be that dramatic," said Philip Weller, who heads the International Commission for the Protection of the Danube when asked about harm to the waterways ecosystem up to now.
But Greenpeace said samples taken from the sludge showed high concentrations of toxic substances.
Greenpeace told reporters in Vienna that the samples taken a day after the spill showed "surprisingly high" levels - 110 milligrams of arsenic and 1.3 milligrams of mercury per kilogram of dry matter.
The results, which also show 660 milligrams of chrome per kilogram, are based on analyses carried out in laboratories in Vienna and in the Hungarian capital, Budapest.
That translates, very roughly, into 50 tons of arsenic, 300 tons of chrome and 500 kilograms, or a half ton, of mercury set free by the spill, Greenpeace officials said.
Greenpeace officials said the detected arsenic concentration is twice the amount normally found in so-called red mud. Analysis of water in a canal near the spill also found arsenic levels 25 times the limit for drinking water.
Hungary's state secretary for the environment, Zoltan Illes, said the henna-coloured sludge covering a 16-square-mile swathe of countryside has "a high content of heavy metals," some of which can cause cancer. He warned of possible environmental hazards, particularly to groundwater systems.
With rain giving way to dry, warmer weather over the past two days, the caustic mud is increasingly turning to airborne dust, which can cause respiratory problems, Illes said.
Government emergency services officials today urged residents near the toxic flood area to wear face masks.
The warnings conflicted with the view of the Hungarian Academy of Sciences which said that while the material remained hazardous, its heavy metal concentrations were not considered dangerous for the environment.
"The academy can say whatever it wants," fumed Barbara Szalai Szita, who lives in Devecser, one of the hardest-hit villages. "All I know is that if I spend 30 minutes outside I get a foul taste in my mouth and my tongue feels strange."
The red sludge entered the Danube on Thursday and was moving downstream today toward Hungary's immediate neighbours, Croatia, Serbia and Romania, amid fears that it will kill the river's fish and plant life.
Monitors were taking samples every few hours to measure damage.
While Hungarian creeks and rivers near the collapsed reservoir have been devastated by the red sludge, the Danube, Europe's second largest river, appeared to be absorbing the blow due to its huge volume of water.
The pH level of the water where the slurry entered the Danube was 9 - well below the 13.5 measured in local waterways hit on Monday by the toxic torrent, said Hungarian rescue agency spokesman Tibor Dobson.
He said such amounts posed no damage to the environment.
A neutral pH level for water is 7, with normal readings ranging from 6.5 to 8.5.
Emergency crews, meanwhile, drained a second industrial reservoir at the alumina plan in Ajka, western Hungary, to prevent a new disaster.
Dobson said 3.5 million cubic feet of fluid from a storage pond close to the burst reservoir was being gradually released into a local river already declared dead in the wake of Monday's environmental catastrophe. Gypsum was being dropped into the Marcal River from helicopters to neutralise the alkaline effect of the fluid, he said.
At monitoring stations in Croatia, Serbia and Romania, officials were taking river samples every few hours.
The long-term effects on the agricultural region will be devastating, however. Some 2,000 acres of topsoil will have to be dug up and replaced because the highly alkaline sludge had killed off all the nutrients and organisms needed to keep the soil healthy, according to Illes.
It is still not known what caused a section of the reservoir to collapse, unleashing a torrent of sludge. Three people are still missing. More than 150 were treated for burns and other injuries, and 10 were still in serious condition.