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UP: Fachverband Umweltphysik

UP 8: Measurement Techniques

UP 8.4: Vortrag

Donnerstag, 17. März 2011, 15:00–15:15, HSZ 204

Sulfur Release from Building Rubble in Urban Soils — •Mareike Brettholle¹, Beate Mekiffer², Charlotte Gleber¹, Julia Sedlmair¹, Gerd Wessolek², and Jürgen Thieme³ — ¹Universität Göttingen, Institut für Röntgenphysik, Friedrich-Hund-Platz 1, 37077 Göttingen — ²TU Berlin, Institut für Ökologie, Am Salzufer 11, 10587 Berlin — ³Brookhaven National Laboratory, NSLS-II Project, Upton, NY 11973, USA

Sulfur accumulation and cycling are central to many biological processes and soil formation. Anthropogenic impact may locally alter the sulfur cycle dramatically. In Berlin, huge amounts of sulfur containing war debris, mainly in terms of building rubble, arose in WWII. This debris was disposed mainly within the city in various dumps. Nowadays, the sulfate content of near-surface groundwater aquifers is continuously rising and has reached the fourfold of the federal limits for drinking water in some areas. This is understood to originate in the lixiviation of war debris within these urban soils. Lately, sulfur K-edge XANES has become a common tool for sulfur speciation in soils. It allows for the identification of functional groups as well as specific binding forms, due to the dependence of the white-line energy of the electronic oxidation state of the sulfur atom. X-ray microscopy on the other hand allows for resolving structures at a wide range of length scales down to a few nanometers. A combination of both methods, elemental mapping and spectromicroscopy, was applied to image the elemental composition of debris loaded soils and particularly to identify its sulfur release by chemical speciation of the occurring sulfur compounds.