Modelling the Potential Effects of the Hungarian Red Mud Disaster on Soil Properties

In this experiment, the effects of the Hungarian red mud disaster were studied in a soil column experiment focusing on element solubility. The effect of flooding with the highly alkaline red mud suspension and the effect of the percolation of precipitation water through the 10 cm thick red mud layer were modelled separately. Both scenarios affected the soil pH up to a depth of 80 cm. An increase in the total element concentration was only observed for Na and Mo, probably due to the leaching of red mud particles measuring 0.05-0.02 and < 0.002 mm in the column. At the same time, the water-soluble concentrations of the potentially toxic elements As, Co, Cr, Cu, Ni, Pb, and Zn rose, at least in the top soil layer, but the concentration values remained below the limit values laid down by quality standards. Over a longer period of time, the main environmental risk raised by the disaster is the secondary salinization of the area.