Recently, it has been recognized that coal ashes and scrubber sludges contain a variety of materials, which, if released in soluble form from a disposal area, could be damaging to the quality of surface and subsurface water. The Resource Conservation and Recovery Act of 1976 (RCRA) places these wastes in a special category. There will be stringent controls placed upon their disposal in the future unless it can be shown that hazardous materials, such as heavy metals, will not leach from disposal areas. Fixation is one potential means of limiting the release of materials.

Two toxicant extraction procedures and agitation with unbuffered deionized water were compared on the basis of heavy metal concentrations of the leachate when these treatments were applied to a fixed (crushed and uncrushed) and unfixed dry additive scrubber waste.

Comparison of the methods indicates that the buffering capacity of a waste, as well as its physical structure, determines the magnitude of heavy metals release. It was found that while fixation may reduce the permeability and surface area-to-volume ratio of a waste, the pH-solubility phenomenon is a controlling factor in some cases for the concentration of metals in simulated leachates.