Radiological investigation of the effects of red mud disaster. 
On 4 October 2010, the gate of a red mud waste dump of a Hungarian alumina factory was damaged and ∼800.000 m(3) of alkaline red mud flooded the vicinity of the dumps.  Red mud samples were collected from the contaminated area and they were investigated from the radiological point of view.  The activity concentrations were as follows: (232)Th: 264 (194-337) Bq kg(-1), (238)U: 265 (197-332) Bq kg(-1), (226)Ra: 180 (143-237) Bq kg(-1), (40)K: 283 (228-360) Bq kg(-1).  As a function of the moisture content (0-28 %), the obtained radon emanation coefficients were relatively high (7.6-20 %) and, consequently, the radon exhalation also increased.