Posted on behalf of Quirin Schiermeier

Soils and water affected by Hungary’s toxic sludge disaster region are less contaminated than was first feared, according to data released by the Hungarian Academy of Sciences.

On 4 October, about 1,000 hectares of land around the villages of Kolontár and Devecser was flooded by a million tonnes of red mud released from a nearby aluminium oxide factory. A working group from the Academy has now collected and analysed 16 soil and water samples in the disaster region.

Concentrations of heavy metals, including cadmium, chromium, mercury, nickel, lead and zinc, were below the values allowed in sewage used as fertilizer in agriculture, says János Szépvölgyi, director of the Academy’s Institute of Materials and Environmental Chemistry in Budapest.

However, arsenic concentration in 8 samples did exceed the limit Hungary allows in sewage. The highest arsenic concentration was 130 micrograms per kilogram – almost twice the allowed limit. But, says Szépvölgyi, the risk is very low that drinking water will be contaminated

Environmentalists are not so sure. Greenpeace warned last week that more than 50 tonnes of arsenic may have been released as a result of the spill. Soil samples taken by its campaigners contained no less than 110 milligrams – not micrograms – of arsenic per kilogram dry mass.

“Their measured values may be correct,” says Szépvölgyi. “But their sampling was apparently not representative, and the interpretation that all the arsenic released will end up in drinking water is just not valid.”

Hungarian scientists will continue to monitor toxicity in the disaster area, he says.