River water chemical analysis seawater

Collectively, the programs mentioned above represent the "state of the art" in the calculation of the equilibrium distribution of species in aqueous systems. As a means of examining the consistency of these programs, two test cases (a dilute river water and an average seawater analysis) were compiled and mailed to more than fifty researchers who have been active in the field of chemical modeling. These test cases may overlook many of the features of specific programs, but they provide a common basis by which most of the programs can be... 

Ba, Sr, and B. Consistency between programs was evaluated by comparing the log of the molal concentrations of free ions and complexes for two test solutions a hypothetical seawater analysis and a hypothetical river water analysis. Comparison of the free major ion concentrations in the river water test case shows excellent agreement for the major species. In the seawater test case there is less agreement and for both test cases the minor species commonly show orders of magnitude differences in concentrations. These differences primarily reflect differences in the thermodynamic data base of each chemical model although other factors such as activity coefficient calculations, redox assumptions, temperature corrections, alkalinity corrections and the number of complexes used all have an affect on the output. 

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