[en] Saltstone is the waste treatment and disposal concept for low-level defense waste at the Savannah River Plant. The waste is a sodium salt solution which has about 230 μCiL in addition to the hazardous characteristics of corrosivity and metal toxicity (Cr⁺⁶ > 100 ppM). Two EPA test procedures are routinely used at SRP to evaluate metal toxicity of wastes and wasteforms. 1) the Extraction Procedure (EP); and 2) the Toxicity Characterization Leaching Procedure (TCLP). The EP test is required by SCDHEC and EPA. The TCLP is used to evaluate the effect of increased surface area on metal leaching from the various SRP wasteforms. EP and TCLP test results are presented for two types of wasteforms, a cement-based saltstone and for a slag-based saltstone. The slag saltstone chemically stabilizes and also physically entraps the chromium. For waste solutions with low to intermediate metal concentrations (up to 5000 ppM), the TCLP extracts typically have lower metal values than the EP extracts. This is attributed to the faster neutralization of the acetic acid by the crushed TCLP sample. Crushing increases surface area and consequently releases more alkalinity from the wasteform matrix and the wasteform pore solution. Metal concentrations in the EP and TCLP extracts are proportional to the concentrations of metals in the pore solution for both the cement or slag-based wasteforms. The pore solution concentrations for cement wasteforms are directly related to the soluble metal concentration in the waste. The metal concentration in the slag wasteform pore solutions are significantly lower than the waste because these metals are reduced lower valences and precipitated as insoluble solid phases. 3 refs., 3 figs., 5 tabs