[en] This report presents a test plan for the experimental determination of the solubilities of several solid compounds of lead, tin, strontium, and selenium that were identified in the literature review as having the potential to limit the concentration of these elements in brines. The objectives of this study are to obtain accurate experimental solubilities of potentially critical compounds of the four elements given above under a wide variety of anticipated repository conditions; to determine the need for a new evaluation of the values of various parameters, such as stability constants and activity coefficients, that are required for an accurate description of the aqueous state of these elements under the anticipated conditions; and to provide a series of measurements with which to compare theoretical predictions for model validation purposes. The indicated priorities are based primarily on the relative expected solubilities of the substances involved and secondarily on the nature of the available information. The literature survey document should be consulted for a detailed discussion of the methodology that led to the selection of these substances. 9 refs., 10 tabs