Computer models for analysis, visualising and decision support in environmental research have become increasingly popular. The Stockhome project, where the urban metabolism of heavy metals in Stockholm was studied, resulted in a database with historical data of the use of goods containing cadmium (Cd), chromium (Cr),copper (Cu), lead (Pb), mercury (Hg), nickel (Ni) and zinc (Zn). A spreadsheet model was developed to study flows and stocks of the metal consumption process and emissions. The model indicates uncertainties of the data, societal aspects such as field of use and rights of disposition of the goods. By considering goods as the drivers of the emissions, the model would be well suited for policy support.