A 600-years pollution history reconstruction using Lake Sediments from Bad Waldsee, southern Germany

Annual lake sediments are excellent high-resolution archives for reconstructing historical pollution. Usually, pollution reconstructions date back to the beginning of industrialization in the early 19^th century. Here, we present a long-term record form Lake Stadtsee located in the city of Bad Waldsee. Using historical written documents, the history of pollution can be linked to the economic activities in the city. In an absolutely dated sediment core we explored the concentration and composition patterns of Polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals together with macro charcoal record at 1 cm steps.

First findings indicate that PAHs were primarily derived from pyrogenic, rather than petrogenic sources throughout the entire time interval. These most probably correspond to urban fire or domestic heating. The general trend observed by using PAH diagnostic ratios, is that the sources have shifted from low temperature pre-industrial combustion processes towards high temperature combustion processes in more recent times. Macro charcoal analysis revealed two main phases of biomass burning, which were separated by a fire free interval for more than 200 years. The first phase in the late Medieval period (653−533 cal BP), shows high proportions of burned grass and monocot leaves, whereas in the second phase in the early Modern Times (313 cal BP until today) wood was the main fire fuel. The molecular ratio pattern of specific methylated-phenanthrene isomers also indicates a change of fuel sources. Heavy metal analyses are currently being conducted. We expect chemical signatures of historical town main crafts (tanneries, smithies, textile bleaching).