April 5, 2012 by Adam Peters

The Centre for Ecology and Hydrology have recently released an updated version of the Windermere Humic Aqueous Model (WHAM). WHAM is a chemical speciation model for predicting the speciation of metals in aqueous systems containing naturally occurring organic ligands. Previous versions of WHAM have been critical in the development of Biotic Ligand Models (BLMs) for predicting the toxicity of trace metals to aquatic organisms. The BLMs for copper and zinc both used WHAM (Model V), and the BLMs for nickel and manganese both used WHAM6.

WHAM7 includes several developments from the previous versions, including a more extensive range of metals for which binding to organic matter can be calculated, allows the precipitation of some important metal hydroxides to be simulated, and can also be used as a toxicity model.

Whilst there are some alternatives, such as Visual MINTEQ, I’ve always found WHAM6 to be easier to use for similar problems. My initial impression of WHAM7 is that it is probably going to be even easier to use than WHAM6, and for a wider variety of metals than has been possible previously.

More information about WHAM7 can be found on the CEH website WHAM7.