Thomas Raab, Brandenburg Technical University (Germany)
Kerstin Hürkamp, Technical University (Germany)
Jörg Völkel, Technical University (Germany)
Oliver Bens, GeoForschungsZentrum (Germany)
Reinhard Hüttl, GeoForschungsZentrum (Germany)
Metal contamination is a prominent and worldwide phenomenon of soil pollution, mainly considered as a consequence of intensive human activities since the onset of the Industrial Age. The exploitation of natural resources by surface and underground mining is one of the main anthropogenic impacts on soil landscapes since thousands of years. For example, metal contamination of soils in Central Europe can be seen to date back to the Metal Ages at least. However, in the context of the establishment of future-oriented soil conservation strategies these historic and prehistoric soil pollutions are often misinterpreted or even ignored. The absence of documentary evidence as well as socio-economic and landscape changes after the end of the active mining present major problems for the detection of historic and prehistoric soil contamination. In addition to this and in contrast to industrial post-mining landscapes, contamination of soils in historic and prehistoric mining areas may have a more regional or local disparity because of differing technical and economical processes.
We present a study from Freihung (Upper Palatinate, Bavaria, Germany), where lead was mined from the 15th to the 20th century. Small-scale lead contaminations in alluvial soils of more than 20 000 mg/kg are detected on a landscape level by the innovative technique of field portable X-ray fluorescence (FPXRF) analysis. The lead concentrations are compared with contents of iron, sulphur, nitrogen, and carbon of the investigated soils. We evaluate soil contamination data in consideration of floodplain renaturation concepts concluding that a new anthropogenic intensification of fluvial dynamics could re-activate the stored lead from the alluvial soils. With respect to rehabilitation activities knowledge on historic and prehistoric soil contamination serves as a basis for modern concepts of sustainable land use in post-industrialised landscapes.