『Abstract
This study presents a combined geochemical and mineralogical
survey of urban surface soils. Many studies on urban soils are
restricted to purely chemical surveys in order to investigate
soil pollution caused by anthropogenic activities such as traffic,
heating, industrial processing, waste disposal and many more.
In environmental studies, chemical elements are often distinguished
as lithogenic and anthropogenic elements. As a novel contribution
to those studies, the authors combined the analysis of a broad
set of chemical elements with the analysis of the main mineralogical
phases. The semi-quantification of mineralogical phases supported
the assignment of groups of chemical elements to lithogenic or
anthropogenic origin. Minerals are important sinks for toxic elements.
Thus, knowledge about their distribution in soils is crucial for
the assessment of the environmental hazards due to pollution of
urban soils. In Pforzheim, surface soils (0-5 cm depth) from various
land use types (forest, agriculture, urban green space, settlement
areas of various site densities) overlying different geological
units (clastic and chemical sediments) were investigated. Urban
surface soils of Pforzheim reflect to a considerable degree the
mineral and chemical composition of parent rocks. Irrespective
of the parent rocks, elevated concentrations of heavy metals (Zn,
Cu, Pb, Sn, Ag) were found in soils throughout the whole inner
urban settlement area of Pforzheim indicating pollution. These
pollutions will tend to accumulate in inner urban surface soils
according to the available adsorption capacity, which is normally
higher in soils overlying limestone than in soils overlying sandstone.
However, inner urban surface soils overlying sandstone show elevated
concentrations of carbonates, phyllo-silicates and Fe and elevated
pH values compared with forest soils overlying sandstone. Thus,
in comparison to forest soils overlying sandstones, inner urban
soils overlying sandstone affected by pollution concurrently posses
elevated concentrations of mineral phases typically providing
relatively high adsorption capacities for heavy metals.』
1. Introduction
2. Area of investigation
3. Methodology
3.1. Sampling and sample preparation
3.2. Analyses
4. Results
5. Discussion
5.1. Spatial distribution of trace metal pollution of Pforzheim
surface soils
5.2. The urban vs. geogenic impact on the mineral and geochemical
composition of surface soils
5.2.1. The mineral and geochemical composition of the ground
mass of Pforzheim surface soils
5.2.2. Residual phases and weathering products
5.3. Soil density and soil fraction of coarse grains
6. Summary and conclusions
Acknowledgements
References