Abstract

This report discusses the various factors (Capacity controlling parameters) which determine the extent of storage of chemicals and the results of a workshop which dealt with prediction and modelling of Chemical Time Bombs (CTBs) related to heavy metal contamination. Combinations of inputs like acidification with deposition of metals from the atmosphere may cause an effect which is worse than each of them on their own. Important are those cases where the capacity of the soil/sediment to retain chemicals changes. Examples are changes in hydrology, changing land use and civil engineering works. Qualitatively we can predict under these circumstances thath the pH will change, organic matter content will changes etc. Also many models are available to predict the effect of single or a few parameters in heavy metals behaviour, but few if not any to predict the combined effects. For these dynamic changes we selected changes in hydrology and changes in land use as topics for the dicussion in the workshop. The last part of the workshops was devoted to constructing research proposals to fill in gaps in our knowledge.