A procedure to identify natural arsenic sources, applied in an affected area in North Rhine-Westphalia, Germany

Journal article

The aim of the study was to identify the geogenic source for elevated arsenic (As) concentrations recently discovered in soils of the Heubach plain, North Rhine-Westphalia, Germany. Therefore, a catalogue of conditions that an As source has to fulfil in order to be considered as geogenic was formulated, including the source's linkage to the sink, its mineralogy, As total content, As mobilization potential, groundwater redox conditions and As output. Accordingly, mineralogical, geo- and hydrochemical investigations were carried out, including X-ray diffractometry, microscopy, ICP-OES and AAS analysis and a sequential extraction procedure. Paleo bog iron ores (PBIOs) of Tertiary age, occurring within unconsolidated sands (Haltern-layers, Santonian-Lower Campanian), and glauconitic marlstones (Dülmen-layers, Lower Campanian) were examined. Results indicate that output from the PBIOs is responsible for the elevated As levels. Accounting their diverse mineralogy, five types of PBIOs were defined. Type-dependent, they at least partly fulfil all of the formulated requirements. The relations and behaviour of As sources and sinks in space and time could be clarified for the area of interest. The approach presented in this paper may offer a tool for identifying natural As sources worldwide. © 2008 Springer-Verlag Berlin Heidelberg.

Authors: Banning, A; Coldewey, W; Göbel, P

• Journal: Environmental Geology
• Volume: 57
• Issue: 4
• Pages: 775-787
• Publication date: 2009-04-01
• DOI: 10.1007/s00254-008-1355-4
• EISSN: 1866-6299
• ISSN: 0943-0105
• Language: English
• Keywords: Arsenic source; Redox conditions; Bog iron ore; Haltern-layers; Mobilization potential; Germany