U.S. Geological Survey
Water-Resources Investigations Report 95-4227, 1995, 143 p.
This is the user's guide to PHREEQC, a computer program written in the C programming language that performs a wide variety of aqueous geochemical calculations. PHREEQC is based on an ion-association aqueous model and has capabilities for (1) speciation and saturation-index calculations, (2) reaction-path and advective-transport calculations involving specified irreversible reactions, mixing of solutions, mineral and gas equilibria, surface-complexation reactions, and ion-exchange reactions, and (3) inverse modeling, which finds sets of mineral and gas mole transfers that account for composition differences between waters, within specified compositional uncertainties.
TABLE OF CONTENTS