The soils in the study area Zemianske Kostolany were polluted with fly ash material after dam failure of the coal-ash pond (1965). Fly ash represents possible source of potentially toxic elements, because meteoric water or groundwater may percolate through and interact with the ash materials in soils, producing leachates that contain elevated levels of trace elements, in our case, arsenic. The main objective of this study was to assess the potential of arsenic release into the environment. Amount of released arsenic from ash soils was performed by using single-step extraction with distilled water. The results show that more arsenic was released from contaminated subsoils. In a depth> 40 cm total released amounts of arsenic vary between 21.9-71.97 mg. kg^ sup-1^. Acid ammonium oxalate was used to determination of amorphous inorganic Fe and Al in the ash soils. Positive correlations were confirmed between arsenic concentrations and total iron and aluminium contents. It indicates that oxyhydroxides of iron and aluminium may control the distribution of arsenic in soils