From 1940 till 1963 the Swiss Army disposed ca. 3000t munitions in Lake Thun. The most abundant organic explosives in these munitions deposits are 2,4,6-trinitrotoluene (500t), nitrocellulose (200t), nitroglycerine (50t) and nitropenta (20t). Smaller amounts of hexogen and tetryl (5t each) are also present. In order to investigate the occurrence of these compounds and of their metabolites in lake water GC-MS and LC-MS/MS based analytical methods were developed. These methods allowed for detection limits in the order of some ng/L. Water samples from various depths thus far showed no detectable concentrations of any of the investigated compounds. In addition, incubation experiments were carried out to investigate the degradation of the organic explosives in lake water and in water containing suspended sediment. The rate constants, adsorption coefficients and product yields obtained were implemented in a water-sediment model. This model was used to predict the dispersion of the organic explosives as well as of their metabolites from sediment covered munitions in the sediment and their entry to the water column.

Vortragssprache: englisch