Abstract
Inverse analytical techniques were used to model solute distributions and determine transport parameters for two flow systems in the Yakima Basalt subgroup at the Hanford Site in Washington state. Previous studies of these flow systems used chloride as a tracer to determine the transverse dispersivities of several of the Hanford flow systems. This study analyzes three reactive solute distributions, two of which are coincident, to determine aquifer and solute reactions parameters. In addition to modeling the transport of two solutes, a chemical speciation model, MINTEQA2, was used to determine saturation indices for the sample waters in an effort to verify observed secondary mineralization. Boron and potassium were the two solute distributions modeled in this study. The analytical model results accurately reproduce the observed field conditions, comply with the assumptions of the conceptual model, and match the results of the previous chloride study. The parameters determined by the analytical model include the source size and dimension, transverse dispersivity, and reaction rate/solute velocity ratio. The reaction rate term is used to describe the first order reactions experienced by boron and potassium. This term is believed to represent the affect of both precipitation and non-equilibrium sorption reactions. Due to the nature of the problem, this ratio cannot be separated for its individual terms. However, the relative rates of reaction for the solutes are determined.
Adamski, Mark Robert (1993). Modeling the reactive inorganic solute distributions in the groundwater flow systems of the Hanford Site using inverse analytical modeling techniques. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1993 -THESIS -A219.