The establishment of EVISA is funded by the EU through
the Fifth Framework Programme (G7RT- CT- 2002- 05112).
Supporters of EVISA includes:
WHAM (Windermere Humic-Aqueous Model) is designed to
calculate equilibrium chemical speciation in surface and ground waters, sediments and
soils. The model is especially suitable for problems where the chemical speciation is
dominated by organic matter (humic substances). WHAM combines Humic Ion-Binding Model V
with a simple inorganic speciation code for aqueous solutions. Precipitation of aluminium
and iron oxides, cation-exchange on an idealized clay mineral, and adsorption-desorption
reactions of fulvic acid are also taken into account. The importance of ion accumulation
in the diffuse layers surrounding the humic molecules is emphasized. Model calculations
are performed with a BASIC computer code running on a Personal Computer.