October 6, 2010

expert reaction to the spillage of aluminium mining waste in Hungary

An accident at an aluminium plant in Hungary led to the spillage of thousands of cubic meters of toxic red sludge.

Prof Paul L Younger, Director of the Newcastle Institute for Research on Sustainability, Newcastle University, said:

“The dramatic spill of red mud in Hungary is but the latest in a long list of similar spills around the world, in which watery suspensions of solids left behind after mineral processing escape from large surface reservoirs in which they are stowed. It is particularly disappointing that the collapse of a red mud reservoir of this sort has taken place in a European country fully four years after the European Union enacted its Directive on the management of waste from the extractive industries, which was supposed to put a stop to these sorts of incidents.

“Similar spills in Spain (in 1998) and Romania (2000) spurred development of the Directive, but if it was working effectively the Hungarian red mud outburst would never have happened. Red mud itself is not a particularly toxic substance, expect that it is very alkaline, which means it has a tendency to be aggressive towards skin and other natural tissues. So the red mud spill is definitely bad news for fish, and you certainly wouldn’t want to bathe in it; for instance, most kitchen cleaners are strong alkalis, and you have to be careful not to get them on your hands or in your eyes.”

Simon Rickaby, Chair of the IMarEST Pollution and Salvage Special Interest Group, and Managing Director of Braemar Howells Ltd., said:

“”In situations such as this spending 10 minutes thinking can save 6 hours of wasted effort. At the moment, the numbers of people who are known to have died are small and this has happened quite quickly, which would indicate that they may not have died as a result of the chemicals within the spill; their cause of death will, however, need to be confirmed. If birds and other local wildlife nearby are not affected then this would also suggest that the chemicals involved are not airborne.

“Before any cleanup operation can begin, the first priority will be to contain the spill in whatever way possible and to prevent it from leaking into the local water course; any ground seepage will also need to be determined. The second priority will be to analyse the spill in as much detail as possible from as many locations as possible – sampling from a large area will help ensure that worst case scenario estimates can be figured out.”

Dr Martin Preston, Marine Chemist at the University of Liverpool, said:

“Red mud is a by-product of the Bayer process in which aluminium oxide is extracted from bauxite ore using high temperatures and sodium hydroxide. About 1-2 tonnes of red mud are produced per tonne of aluminium. It consists largely of the non- alkali soluble components of bauxite with iron oxides being amongst the most important (hence the red colour).

“Red mud may contain radioactive elements largely from the 232 Thorium decay series with a contribution from the 238 Uranium decay series. The radioactivity is more concentrated by a factor of 3 or so in the red mud than in the original ore. However red mud is not normally treated as a radioactive waste.

“There are no widespread uses of red mud. Normal practice is to try and reduce its high pH and then allow it to dry out in lagoons. It is then covered in soil and the land remediated. There are reports of red mud being used in ceramics, building materials and the cement and pigment industries but on nothing like the scale of production. Basically red mud is a true waste with virtually no redeemable qualities.

“If the red mud residues get into the water courses the potential damage will come from two main sources:
1),the high pH of the waste which has the potential to make waterways too alkaline to support life, and
2),the clogging, smothering nature of the waste which has a large proportion of small particles in it.
These have the potential to interfere with animal and plant life in general and particularly fish where fine grained particles can damage gills and inhibit respiration.”