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INTRODUCTION
Database Files: Elements, Aqueous Species, Exchange Species, Surface Species, and Pure Phases
PHREEQC uses a database file to define the set of elements and element redox states, ion exchangers, surface complexers, and pure phases that are used in calculations. The database file contains all of the stoichiometry and thermodynamic data for aqueous species, exchange species, surface species, and pure phases. These data are defined through the following keyword data blocks: SOLUTION_MASTER_SPECIES, SOLUTION_SPECIES, EXCHANGE_MASTER_SPECIES, EXCHANGE_SPECIES, SURFACE_MASTER_SPECIES, SURFACE_SPECIES, and PHASES. Custom database files can be written using these keywords. In addition, database files can be modified at run time through the use of these keywords in the input file.
Three database files are distributed with PHREEQC and PhreeqcI, phreeqc.dat, wateq4f.dat, and minteq.dat. The file phreeqc.dat is derived from the database file for the geochemical program phreeqe (Parkhurst and others, 1980), but the data are consistent with wateq4f.dat for the minerals and species that are common to both. The file phreeqc.dat contains data for the elements Al, B, Ba, Br, C, Ca, Cd, Cl, Cu, F, Fe, K, Li, Mg, Mn, N, Na, P, Pb, S, Sr, Si, and Zn. The file wateq4f.dat is derived from the database file for WATEQ4F (Ball and Nordstrom, 1991) and contains all of the elements from phreeqc.dat plus As, Cs, I, Ni, Rb, Se, and U. In addition, wateq4f.dat has data for organic ligands labeled Fulvate and Humate. The file minteq.dat is translated from the data files of MINTEQA2 (Allison and others, 1990).
PhreeqcI--A GUI for the Geochemical Program PHREEQC - 10 OCT 97
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