MINTEQ

E-mail minteq.productinfo mineralstech.com Web site www.mineralstech.com/body minteq... 

Visual Minteq origin Jon Petter Gustafsson Land and Water Resources Engineering Brinellvagen 28 100 44 Stockholm Royal Institute of Technology, KTH Sweden... 

MINTEQA2 http //www.epa.gov/ceampubl/mmedia/minteq/index.htm MINTEQA2 is an equilibrium speciation model that can be used to calculate the equilibrium composition of dilute aqueous solutions in the laboratory or in natural aqueous systems. The model is useful for calculating the equilibrium mass distribution among dissolved species, adsorbed species, and multiple solid phases under a variety of conditions including a gas phase with constant partial pressures. 

Felmy, A. R. Girvin, D. C. and Jenne, E. A. "MINTEQ - A Computer Program for Calculating Aqueous Geochemical Equilibria" Battelle, Pacific Northwest Laboratories Richland, Washington (in preparation). 

Matrix extrapolation undertaken by this model means that the model calculates the free metal ion concentration as the toxic species, given a total metal concentration and site-specific conditions in terms of water hardness, DOC, salinity, and so on. As an example, according to the MINTEQ model, a type of water with a hardness of 10 mg/L CaC03, a DOC content of 10 mg/L, a total Zn concentration of 10 mg/L, and a variable pH gives a distribution of Zn species as given in Table 2.5. 

Illustration of the distribution of chemical species in an example output of the MINTEQ speciation program... 

De Groot et al. (1998) also gave regression parameters for calculating the total metal concentration in pore water from the total concentration in the soil. If site-specific physicochemical pore water characteristics are also available, the predicted total metal concentration in pore water can be extrapolated to the bioavailable ion concentration in pore water by site-specific application of the MINTEQ model. 

Allison J, Brown DS, Novo-Gradac K. US Environmental Protection Agency, Environmental Research Laboratory. 1991. MINTEQA2/PROEFA2 a geochemical assessment model for environmental systems, http //www.epa.gov/ceampubl/mmedia/minteq/ index.htm (accessed July 28, 2005). 

D. J. Monagle, III, Sr. VP/Managing Dir.-Specialty Minerals Paper PCC Douglas W. Mayger, VP/Managing Dir.-Specialty Minerals Performance William Wilkins, Sr. VP/Managing Dir.-Minteq International, Inc. 

The data sets WATEQ4F.dat, MINTEQ.dat, PHREEQC.dat and LLNL.dat are automatically installed with the program PHREEQC and can be chosen from the menu item Calculations/File under Database File. The internal structure of these thermodynamic data sets has already been explained in great detail in chapter... 

EDTA cannot be found in the previously used data set WATEQ4F.dat. It is only defined in the data set MINTEQ.dat. Therefore, use this one. The key word for the addition of EDTA is the same as for the exercise in chapter 3.1.1.9.]... 

The thermodynamic equilibrium models, including surface complexation models, require the solution of a complex mathematical equation system. For this reason, many computer programs (e.g., CHEAQC, CHEMEQL, CHESS, EQ3/6, F1TEQL, Geochemist s Workbench, H ARPHRQ, JESS, MINTEQ and its versions, NETPATH, PHREEQC, PHRQPITZ, WHAM, etc.) have been developed to calculate the concentration and activity of chemical species, estimate the type and amount of minerals formed or dissolved, and the type and amount of sorbed complexes. 

These programs are able to model the geological systems soil/rock-aqueous solution systems that is the concentration and distribution of the thermodynamically stable species can be determined based on the total concentrations of the components and the parameters just mentioned. In addition, the programs can also be used to estimate thermodynamic equilibrium constants and/or surface parameters from the concentrations of the species determined through experiments. Thermodynamic equilibrium constants can be found in tables (Pourbaix 1966) or databases (e.g., Common Thermodynamic Database Project, CHESS, MINTEQ, Visual MINTEQ, NEA Thermodynamical Data Base Project (TDB), JESS, Thermo-Calc Databases). Some programs (e.g., NETPATH, PHREEQC) also consider the flowing parameters. 

Brown, D.S. and Allison, J.D. (1987). MINTEQAl Equilibrium Metal Speciation Model A user s manual. Athens, Georgia, USEPA Environmental Research Laboratory, Office of Research and Development... 

A computer code is obviously not a model. A computer code that incorporates a geochemical model is one of several possible tools for interpreting water-rock interactions in low-temperature geochemistry. The computer codes in common use and examples of their application will be the main focus of this chapter. It is unfortunate that one commonly finds, in the literature, reference to the MINTEQ model or the PHREEQE model or the EQ3/6 model when these are not models but computer codes. Some of the models used by these codes are the same so that a different code name does not necessarily mean a different model is being used. 

Felmy A. R., Girvin D. C., and Jenne E. A. (1984) MINTEQ— A Computer Program for Calculating Aqueous Geochemical Equilibria. US Environ. Prot. Agency (EPA-600/3-84-032). 

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