A Method for Determining the Reactivity of Hazardous Wastes That Generate Toxic Gases

An analytical system for measuring the evolution of hydrocyanic acid (HCN) and hydrogen sulfide (H₂S) from waste materials has been evaluated. The procedure involves acidifying the sample in an aqueous diluent and then drawing a current of air through the vapor space and onto a Draeger stain tube specific for each analyte. Estimates of method precision, analyte recovery, and interferences of one analyte on the other were carried out. A round-robin interlaboratory study was conducted on a variety of HCN- and H₂S-bearing wastes. The results of this study indicated that the presence of interferences and the poor method precision made this test method inappropriate for measuring HCN in wastes. On the other hand, study data suggested that, with some refinements, this procedure is a potentially useful technique for measuring H₂S in waste materials.