Regionalized concentrations and fingerprints of polycyclic aromatic hydrocarbons (PAHs) in German forest soils

- Highest PAH concentrations were found relatively close to potential emitters.
- PAH fingerprints show regional-specific distribution patterns.
- Enrichment factors between mineral soils and humic layers depend on humus type.
- Regional sources dominate contents and patterns more than long-range transport.

Samples of 474 forest stands in Germany were analysed for concentrations of polycyclic aromatic hydrocarbons (PAHs) in three sampling depths. Enhanced concentrations were mainly found at spots relatively close to densely industrialized and urbanized regions and at some topographically elevated areas. Average enrichment factors between mineral soil and humic layer depend on humus type i.e. decrease from mull via moder to mor. Based on their compound-patterns, the observed samples could be assigned to three main clusters. For some parts of our study area a uniform assignment of samples to clusters over larger regions could be identified. For instance, samples taken at vicinity to brown-coal strip-mining districts are characterized by high relative abundances of low-molecular-weight PAHs. These results suggest that PAHs are more likely originated from local and regional emitters rather than from long-range transport and that specific source-regions can be identified based on PAH fingerprints.