Versions 3.8.2 of all PHREEQC programs have been released

[dlparkhurst]

--Installation files and (or) source code are at https://github.com/usgs-coupled.  Installation files for each program are available for the latest Release (right-hand side) of each program's Git page (https://github.com/usgs-coupled/phreeqci/releases, for example). The files are labeled Assets at the bottom of each Release.

--Latest Python version of PhreeqcRM is available through pip or conda:

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pip install phreeqcrm
or

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conda install -c conda-forge phreeqcrm


--Latest R version of phreeqc is available from CRAN.

--Mac version of PHREEQC 3.8.0 (soon to be 3.8.2) is available at https://visions-of-quality.com/macphreeqc/ or https://sourceforge.net/projects/macphreeqc/

Here are the major enhancements in the new versions:

1. PHREEQC:
A new viscosity calculation and improved calculation of specific conductance have been implemented in phreeqc.dat, Amm.dat, and pitzer.dat.

We have added the latest version of the database Thermoddem to the distributions of PHREEQC programs.

A new database has been added Kinec_v3.dat (replaces Kinec.v2.dat) from Oelkers and coworkers in the llnl.dat style that implements RATES definitions for a wide range of minerals.

A new database phreeqc_rate.dat includes rate parameters from Hermanska and and others (2023) and Palandri and Kharaka (2004). An example from Sverdrup and others (2019) is also included. New keywords have been implemented to to define tables of rate parameters RATE_PARAMETERS_HERMANSKA, RATE_PARAMETERS_PK, and RATE_PARAMETERS_SVD and new Basic functions calculate rates (mol/m^2/s) from the tables of parameters--RATE_HERMANSKA, RATE_PK, and RATE_SVD. Comments within the database explain the use of the new rate capabilities. You must write your own RATES definitions, adding any desired surface area and affinity factors.

MEAN_GAMMAS is a new keyword that defines the stoichiometries of salts for calculation of mean activity coefficients. MEANG is a Basic function that calculates the mean activity coefficient for a salt. Phreeqc.dat, Amm.dat, and pitzer.dat now contain definitions for most salts appropriate to the database.

Several new Basic functions have been added including EQUIV_FRAC, F_VISC, GET$, MCD_JCONC, MCD_JTOT, MEANG, PHASE_EQUATION$, PUT$, RATE_HERMANSKA, RATE_PK, RATE_SVD, SET_DIFFC, SPECIES_EQUATION$, VISCOS, and VISCOS_0.

The units conversion from /L and /kgs to /kgw has been improved when using the "calc" option of -density in SOLUTION definitions for the databases phreeqc.dat, Amm.dat, and pitzer.dat.

2. BMIPhreeqcRM: BMI (Basic Model Interface) has been implemented for PhreeqcRM. BMIPhreeqcRM is intended to be a reaction module that is coupled with multicomponent-transport models. The motivation of implementing BMI was to be able to link PhreeqcRM with Modflow 6. BMIPhreeqcRM includes all of the methods of PhreeqcRM (including some new PhreeqcRM methods to simplify initializing a reactive-transport model and to facilitate getting and setting element and species concentrations). BMIPhreeqcRM adds all of the methods that are specified by the BMI standards, although some methods are not applicable and do not return useful information.

BMI uses the methods Initialize, Update (time step), and Finalize to couple models. Additional features are the ability to determine variables that can be input and output, units of variables, retrieval of variables with the method GetValue, and setting of variables with the method SetValue. As suggested by the BMI standard, BMIPhreeqcRM can be initialized with a YAML file.

The BMIPhreeqcRM method AddOutputVars combined with the method GetValue provides a means of retrieving almost all values calculated by PHREEQC. GetValue returns an array of values corresponding to each cell in the transport model. For example,

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AddOutputVars("EquilibriumPhases", "true");
allows

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GetValue(equilibrium_phases_moles_Calcite", calcite_moles)
to return the number of moles of calcite in each cell in the array calcite_moles. By default, most variables are available except for activities and molalities of species. The complete list of output variables is obtained with the method GetOutputVars.

BMIPhreeqcRM is available in C++, Fortran, Python, and C. (The C version has all of the capabilities of BMIPhreeqcRM, but the methods are slightly different from the BMI C standard).