MINTEQA2 is a geochemical equilibrium speciation model for dilute aqueous systems. The model can be used to calculate the mass distribution between the dissolved, adsorbed, and multiple solid phases under a variety of conditions including a gas phase with constant partial pressure. Seven adsorption models are available in MINTEQA2. Input data consist of total dissolved concentrations for the components of interest, and optionally, parameters such as pH, pe, or the partial pressure of one or more gases. A measured value of pH and/or pe may be specified as equilibrium values, or MINTEQA2 can calculate equilibrium values. Also, a mineral may be specified as at equilibrium with the solution and either 1) subject to dissolution if conditions warrant, or 2) not subject to complete dissolution. MINTEQA2 has an extensive thermodynamic database that is adequate for solving a broad range of problems without need for additional user-supplied equilibrium constants. The standard database can also be easily modified by the user if necessary.

MINTEQA2 is complemented by an interactive preprocessor PRODEFA2, which prepares input data files for MINTEQA2. The program produces tabular and graphical output. Public domain MINTEQA2 is a DOS-based program, distributed on DOS-formatted disks containing source code and executable image. The user's manual includes installation instructions and the program documentation.

SYSTEM REQUIREMENTS

Intel 80i86 based computer, 640 Kb RAM, DOS 3.0 or higher; math coprocessor optional.

Authors: J.D. Allison, D.S. Brown, and K.J. Novo-Gradac (U.S. EPA).