contaminants, such as PAHs in different grain size fractions.
Because of their different compositions and origins, PAHs associated
with particles may show different distribution characteristics.
However, a finding of uniform PAH profiles among
different size fractions can be taken as evidence for a common
source or, alternatively, for the presence of dynamic exchange
and equilibration processes within the sediment/soil matrix
(Ahrens and Depree, 2004). In addition, different sized particles
in sediment/soil may show different bioavailability
(Talley et al., 2002). It is especially important for the sediment/
soil dwelling animals, such as earthworms, which selectively
feed on small particles (Shipitalo and Protz, 1989;
Zhang and Schrader, 1993).
Previous studies at the Mosel River identified large
amounts of black particles in soils at different sites. Linked
to this, particles had elevated PAH concentrations (Pies
et al., 2006). The aim of this study was to identify, in detail,
the dominant geosorbents in the floodplain soils of the Mosel
River. Therefore we chose one typical site identified from the
previous studies (close to the town of Leiwen) for a detailed
investigation. Soils were separated into several fractions according
to the grain size and density. The purposes of this
study were: (1) to identify these black particles; (2) to characterize
the distribution of PAHs in the soil and (3) to elucidate
the dominant geosorbents for the PAHs.