The reported investigation was focused on the leaching behaviour of typical large-tonal waste (two spoil-heap materials, two malten sands and a flue -gas refining residue). Beside the characterization of the solid material (via X-ray fluorescence analysis and extraction with aqua regia) and the determination of the leachability by water also a four-step extraction sequence was applied to determine the binding forms of heavy metals in the solid matrix and thus to identify their release potential. The influence of long-term pH changes on the mobility of heavy metals and of arsenic was simulated in agitation test at pH = 4 and pH = 11 over 24 hours. The acid and base neutralization capacities, respectively resulting from such pH_stat tests, provide in addition to the leached fraction of constituents a more realistic assessment of waste material in view of an environment-protecting reuse or disposal.