Geochemical Investigations in the Urban Areas of Berlin

Abstract

The present s ta te o f knowledge of u rban geochemistry of Berlin can be characterized, in general, by a completed geochemical inventory. Industrial emission of toxic substances, which have been generated in different industr ial processes by various companies, have led to a variable and high accumulation of toxic materials in the soils of Berlin. A b o u t 4000 soil samples were taken in suburban and poorly contaminated areas from the depth of 0.0-0.2 m and analysed for 11 major and 42 trace elements; TOC, pH and electrical conductivity were also determined. In the topsoils of the city-centre of Berlin and locations of chemical industry organic pollutants, such as hydrocarbons , aromat ics , l ight ha logenated compounds were analysed too. In the surroundings of Berlin about 60 soil profiles were also described and collected to a minimum depth of 150 cm. About 200 soil samples of different urban land uses were leached with IM MgCI2, IM Na-Acetat, 0.04M NO2OHCI and 30% H202 for the determinat ion of metal mobilization and availability. In the densely populated and the industrial areas the sampling density was 40 samples on a 1 km 2. The field observation comprised the informations concerning: geographical and g~ological conditions, land form, urbanizations, mode of land use and vegetation, soil type and horizon, potential sources of contamination. For purposes of evaluation and interpretation of environmental geochemical data we use both mono-element and multi-clement maps (ClusterQ-analysis), or maps of geochemical associations (component-analysis) and geochemical maps of stress capacity for trace elements. These maps are of great importance for the estimation of environmental conditions and the state of load. They are a basis for reasonal ecological decisions in the conflict situation between urban land use planning and the health of men, animals and plants. The element distribution in topsoils shows a clear dependence on the type of urban land use and type of production process and industrial complexes. The distribution and concentrations of the elements AI, K, Na, Rb, Zr, Nb and Ti can be related predominantly to natural geoor pedogenie origin, that means to the composition of the substratum. According to the temporary evaluation the industrial areas are characterized by contaminations of the subsurface soil with Cu-Zn-Pb-Hg-SnNi. The geochemical background of industrial and commercial areas, in relation to the total geogenic background, is characterized by high-contrast